How Does a Piston Flow Meter Work?

What is a piston flow meter?

A piston flow meter is a positive displacement flowmeter, which is mainly used to measure liquid flow. The piston flow meter is composed of a shell, piston mechanism, and other parts. The measured fluid fills a space with a certain volume, and these volume increments are counted and accumulated. It has the advantages of simple structure, reliable work, high accuracy, large range ratio, and little influence on viscosity. It is mostly used for measuring non-corrosive liquids, such as heavy oil or other oils, on small-diameter pipelines.

piston flow meter

Piston flow meter technology

Piston-type flowmeters are commonly used for flow measurement of fuel dispensers. Its structure includes a housing, an upper cover, a lower cover, a piston, a crankshaft, and a distribution valve. The inner cavity of the housing is equipped with four-piston cylinders that cooperate with the piston dynamic seal. The four-piston cylinders are evenly distributed in the circumferential direction on the vertical plane of the crankshaft rotation centerline.

The piston is connected to the crankshaft by a connecting rod. The piston rodless cavity is connected to the inlet and outlet on the upper cover through the distribution valve. A side cover is installed on the casing outside the piston cylinder. The upper cover is equipped with an output shaft that rotates synchronously with the crankshaft. By right Count the number of revolutions of the output shaft to achieve flow measurement.

  • The main disadvantages are:
  • The outer circular surface of the output shaft of the existing piston flowmeter and the upper cover adopts O-ring dynamic sealing cooperation.
  • The high-speed rotation of the output shaft is likely to cause wear to the sealing ring, resulting in a decrease in sealing performance and even leakage.
  • In addition, there are errors in the machining dimensions of the inner cavity of the piston-cylinder of each product. Lead to the measurement error of the piston flowmeter.

Read more General-purpose Flow Totalizer for Data collection and calculation

Features and applications of Piston flow meter

The piston flow meter has a simple structure, reliable work, and a large measuring range.
The measurement accuracy is high and is not affected by viscosity. It can be changed remotely and other advantages.

However, the main components of the measurement part are not corrosion-resistant. Therefore, it can only measure non-corrosive media, such as heavy oil and other petroleum products.

Extended reading: Cylinder Gear flow meter for micro flow measurement.

Piston flow meter working principle

A piston flow meter is a positive displacement flow meter, which is based on the fact that the piston and the metering chamber have been kept in a tangential sealed state. And there is a fixed eccentric distance metering element piston.

Under the action of the pressure difference, a rotational torque is generated on the piston, which makes the piston perform an eccentric rotation movement.

The number of revolutions of the piston is proportional to the flow rate of the fluid. The piston revolution ratio is recorded by the counting mechanism. Then the total flow of fluid can be measured.

The inlet and outlet of the Piston flow meter are separated by a partition. When the measured fluid enters the metering chamber from the inlet, a pressure difference is formed at the inlet and outlet, forcing the piston to rotate counterclockwise as shown in the figure.

The continuous flow of fluid forces the piston to rotate as shown in the figure, forming two and a half-crescent cavities. The piston is forced to rotate under the action of the pressure difference as shown in the figure. V2 fluid is discharged from the outlet. Rotate under the action of pressure difference. V1 fluid is discharged from the outlet, and the fluid bursting out every revolution of the piston is equal to the sum of V1+V2.

Tool: Volumetric Flow Rate & Pipe Diameter to Flow Speed Calculator

Piston flowmeter output signal, such as 4-20mA. The flow signal can be connected to a paperless recorder. Carry out multi-channel flow signal monitoring. What Is A Paperless Recorder?

Piston flowmeter VS gear type flowmeter

Gear flow meters are a type of positive displacement flow meters, used for precise continuous or intermittent measurement of the flow or instantaneous flow of liquid in the pipeline. It is especially suitable for the flow measurement of heavy oil, polyvinyl alcohol, resin, and other high viscosity media.

Piston type flowmeter is an online installation, mechanical flow switch, used for liquid or gas medium. Very small pressure loss, good repeatability, anti-fouling ability, mechanical part, and electronic part are completely isolated, suitable for small flow economy type.

If the flow rate you want to measure is not large, the piston type is better.
If you want to measure a large flow rate, just use a gear type.
If the gas flow is measured, only the piston type can be used

Extended reading: Positive displacement flow meter working principle.

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A Piston Flow Meter is an innovative device that accurately measures fluid flow in pipelines. Sino-Inst, a well-established manufacturer and supplier of Piston Flow Meters, boasts a wealth of experience in the field.

With our top-notch product line, Sino-Inst is the perfect partner for all your flow measurement needs. If you’re in the market for a reliable and efficient Piston Flow Meter, look no further! Contact Sino-Inst today and let them show you what they can do.

And that’s not all, Sino-Inst also offers a range of other flow meters, including turbine flow meters, magnetic flow meters, and more. Let Sino-Inst help you find the perfect flow meter solution for your specific application!

Powder Silo/Bin Level Measurement and Control System

The Silo/Bin level measurement and control system solves the problem of frequent dumping accidents in the powder silo of the mixing station during the feeding process. It avoids the problems of dust flying, waste of cement, and environmental pollution. It reduces the equipment damage caused by the collapse of the dust removal hood of the mixing station Other issues and prevents the safety issues of the workers present.

The importance of Silo/Bin level monitoring

In the production process of the mixing station, the material in the powder silo is replenished in time by means of pneumatic conveying. Most of the dust collectors on the top of the powder silo of the mixing station lack normal maintenance. During the replenishment of the tank body, the pressure of the powder silo is too high, causing “roof fall”. Cement overflows from the dust collector or safety valve. Or “lift the top”, the separation of the top cover of the powder silo from the body of the powder silo occurs.

The intelligent safety system of the powder silo passes through the intelligent detection equipment installed on the silo. achieve:

  • Predict the amount of storage in the warehouse and control the amount of feed;
  • Three-level protection to prevent the occurrence of “top falling” and “lifting top” accidents;
  • Prevent the wrong storage of cement, fly ash, and mineral powder, and prevent construction quality accidents;
  • Cloud platform monitoring platform, real-time monitoring of the status parameters of the powder silo;

Extended Reading: What is level transmitter working principle?

Silo/Bin material level measurement system

System Features

  • Instead of “manual hammering”, the remaining amount of materials in the warehouse can be controlled at any time to provide a basis for procurement and inventory;
  • The resistance rotary switch is intelligently controlled, and the signal is incorporated into the material level measurement system, which greatly extends its service life;
  • Real-time alarm on the feeding surface when feeding, to prevent the occurrence of “roof fall” accidents;
  • The application of product intelligent diagnosis algorithm solves the difficulties of heavy hammer level gauges in the industry that it is too faulty and difficult to maintain;
  • The control system adopts a distributed network system, wireless transmission, stable and reliable, and fast wiring;
  • Reserved information interface to meet the needs of remote control and ERP management system;
  • Distributed control system layout, display the working status of the entire system and equipment parameters on the touch screen;

Extended reading: PID Controller Working Principle

Important components of the system

  1. High-altitude material level detector

Installed on the top of each silo, it is the main measuring equipment of the material level measuring system. It can more accurately monitor the amount of storage in the warehouse in real time, and has the characteristics of resistance to heavy dust and long service life.

  1. High-performance anti-rotation level switch

The anti-rotation material level switch is installed vertically downward to detect whether the motor is working. Through the safety feeding valve to start and stop the rotation resistance, the service life is extended to 3-5 years; with the central control touch screen alarm and the ground terminal alarm, it can effectively prevent the occurrence of “top falling” accidents.

  1. Central control system

It adopts a 15-inch touch LCD screen, an embedded operating system, and is equipped with the material level measurement system software independently developed by the company. The equipment adopts 485 communication interface, which has the characteristics of fast transmission rate, high signal strength, and low failure rate.

  1. Ground display terminal

One set is equipped at the bottom of each silo, which is used for sound and light alarm when the material level triggers the anti-rotation switch alarm (synchronized with the weighing room alarm), real-time display of material weight and percentage, promptly reminding the operator to take measures to avoid accidents.

  1. Safety feeding valve

The safety feeding valve is installed at the feeding port of the powder silo, which can effectively prevent the wrong silo from loading, reduce management costs, ensure the quality of concrete, and prevent production accidents.

  1. Remote display

Remote monitoring shows whether the current silo can be loaded, and guides the vehicle to load the corresponding silo.

Featured Silo Level Sensors

Extended reading: Magnetostrictive Hydraulic Cylinder Position Sensor

Advantages of Radar Silo Level Sensors

High frequency radar Silo Level Sensor is currently the mainstream product for measuring solid level in the world. When measuring solid material level, compared with low frequency radar, high frequency radar has the following advantages:

1) High-frequency radar level gauges (mainly 26GHz and 24GHz) have the advantages of high energy, small beam angle and high precision. However, low-frequency radars have low energy and scattered energy, so all launch angles are large and the directivity is poor. When the diameter of the horn antenna of the low-frequency pulse radar is Φ246, the beam angle is only 15°).

2) The wavelength of 26GHz radar is 11mm, and the wavelength of 6GHz radar is 50mm. When the radar measures the bulk material level, the radar wave reflection mainly comes from the diffuse reflection of the material surface. The intensity of diffuse reflection is proportional to the size of the material and inversely proportional to the wavelength. That is to say, for the same material, the shorter the wavelength is, the easier it is to be reflected, so the echo signal is better during radar measurement. The diameter of most bulk materials is far less than 50mm, which is why 26GHz radar is currently the best choice for bulk material level measurement.

3) Due to the harsh environment on site, dirt, water vapor, etc. will accumulate on the radar antenna over time. The 26GHz radar antenna is small, adding a radome can greatly improve the impact of dirt and water vapor. The 6GHz radar antenna is large, and it is very difficult to add a radome. The overall instrument is large and difficult to clean.

4) When the low-frequency radar (6GHz) measures solids, the measurement range will not exceed 30m. It cannot meet all level measurements of cement lines above 2500T/d scale. The general measurement range of high-frequency radar can reach 70 meters, or even 100 meters. It can fully meet all silos of cement production lines of all scales at present.

5) Because the high-frequency radar level gauge has good directivity and small launch angle. Strong anti-interference ability and so on. It is determined that it is very suitable for the measurement of silos with large aspect ratios. Especially such as calcium carbide furnace material level, converter silo and other material level measurement. Neither of these situations can be measured with low frequency radar.

6) Low frequency radar compared to high frequency radar. Due to its low frequency, the energy is scattered and the energy is not concentrated enough. Therefore, the ability to fight against dust is far inferior to high-frequency radar.

Extended reading: How to Choose the Right Diesel Fuel Level Sensor?

Safe feeding system for powder silo

The remote display of the weighing room shows the warehouse number and the material is allowed to be loaded. The driver holds the card to the ground display terminal and swipes the card if the warehouse allows loading. When the card number is the same as the warehouse number. Only then can the feeding valve be automatically opened.

After the card is valid, the access control baffle is automatically fully opened within 15 seconds. After swiping the card again, the access control shutter will automatically be fully closed within 15 seconds.

The powder safety feeding valve system comes with a closed door detection. Real-time detection of closed door status.

The feeding valve cannot be opened without swiping the card or reading the correct ID information

After loading, the driver needs to swipe his card to close the access control. Then go to the weighing room to hand in the card, otherwise the system prompts that the access control is open. The weighing house will not weigh the vehicle.

At present, the loading port of the cement silo of most mixing plants adopts simple mechanical locking methods. In actual production, it is easy to cause the wrong material to enter the silo, and the loading is not closed and locked. The intelligent material level system for powder silo developed by our company. It has the advantages of easy installation and maintenance, accurate measurement, high safety in use, and no need to stop production during installation. It is currently the preferred solution for real-time measurement of the powder silo level on the market.

Extended reading: 5 Industrial Propane Tank Level Indicators

Solid flow meter | For bulk solids-powder-soybean-cement 

In fact, in addition to monitoring the material level of the bin, we can also know the material level of Silo/Bin by monitoring the flow of solid particles or powder.

What is a solid flow meter?

The solid flow meter is suitable for the measurement of solid mass flow in a wide range of metal-enclosed pipelines from kg/h to t/h. The system is suitable for online monitoring of the flow of solids such as powder, dust, pellets, granules, etc., which are pneumatically conveyed or in free fall (1nm-20mm). Solid flow meters are also called solid powder flow meters, intelligent electrostatic powder flow meters, solid dust flow meters, coal powder flow meters, mineral powder flow meters, lime flow meters, cement flow meters, flour flow meters, petroleum coke powder flow meters.

Read more about: Solid Flow Meter Parameters

More Featured Level Measurement Solutions

FAQ

Simply put, silo levels measurement is divided into contact and non-contact measurement. Technical measures are taken to detect the accumulation height and surface position of granular materials in coal storage bins (raw coal bins, buffer bins, product bins, etc.) in the coal preparation plant. The equipment for detecting the grain position is called the level gauge.

Extended reading: GWR Solid Level Sensor-for Cement silo-Ash powder measure

The point level sensor can indicate whether the fluid level is higher or lower than a specific point. Usually the point level switch is used as a warning indicator. When the liquid level is too high or too low, an alarm is triggered and the liquid level is kept between two points.

Point level sensors have a wide range of types and are suitable for many applications and materials. The float level sensor is a common point level sensor. The float level switch is composed of a fixed rod and afloat; the float has a built-in permanent magnet that moves freely along the fixed rod as the liquid level rises and falls. The magnetic field of the permanent magnet acts on the reed switch. The closer it is to the reed switch, the stronger the force will be. After the threshold, the reed switch is closed. The float level sensor has a sturdy and durable structure and the measurement deviation is less than 1%.

When every possible intermediate level of a tank or container needs to be measured, a continuous level sensor is required, also known as continuous level measurement. This means that the sensor will provide feedback regardless of the liquid level.
For applications that require continuous level measurement such as fuel tanks and storage tanks, the continuous level sensor can indicate the fluid level in a given container that is within the range.

The radar level sensor is a radar level gauge based on the principle of time domain reflection (TDR). The electromagnetic pulse of the radar level gauge propagates along the steel cable or probe at the speed of light. When encountering the surface of the measured medium. Part of the pulse of the radar level gauge is reflected to form an echo and returns to the pulse transmitter along the same path. The distance between the transmitting device and the surface of the measured medium is proportional to the propagation time of the pulse between them. The height of the liquid level is calculated.

Read more: Non-Contacting Radar Level Measurement


Sino-Inst offers more than 40 powder silo/silo level measurement and control systems. About 50% of them are level gauges and 50% are silo level sensors. Suitable for highest and lowest level product detection, they can be installed in flat bottom silos and hopper silos to prevent silos from overflowing or emptying.

There are various powder silo/silo level measurement and control systems for you to choose, such as free samples, paid samples.

Sino-Inst is a globally recognized powder silo/silo level measurement and control system instrumentation supplier and manufacturer, located in China.

Sino-Inst offers a wide range of high-quality silo level sensors designed for various environments at competitive prices. Helps operators accurately monitor and measure liquid level and flow in silos. A range of non-contact solutions means that the operator does not have to come into direct contact with any substance. It also means that the process is not interrupted.

Sino-Inst’s entire team is well trained, so we can ensure that each customer’s needs are met. If you need any help with your product requirements, whether it is a silo level sensor, level sensors, or other equipment, please give us a call.

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Bidirectional Flow Measurement

What is bidirectional flow?

Bidirectional flow refers to forward and directional flow. Bi-directional flow lines are not common in most process plants. The measurement of unidirectional flow is easy to understand and is applicable to all types of flow technologies. However, most flow technologies cannot accurately measure two-way flow.
They always cause difficulties for process and instrument designers. For two-way flow, the pipeline scheme uses the same pipeline to achieve the transport and/or control function of the opposite flow (forward or reverse flow) according to the process conditions and goals.

Can the flow meter perform bidirectional measurement?

If the flow direction of the medium in the pipeline is reversed. Does the flow meter need to be installed with a flow meter for forwarding use and a flow meter for reverse use accordingly? Is there a flow meter for normal measurement that does not consider the flow direction?

  1. If you just look at the flow rate, you can. For example, an electromagnetic flowmeter. It doesn’t matter if you measure in the whole direction or in the reverse direction. Change the reverse measurement to allow in the prerequisite electromagnetic flowmeter settings.
  2. It’s hard to say if you still need a cumulative amount. How do you convert the cumulative amount you measured forward and the cumulative amount you measured backward? Whether to subtract or add depends on your actual situation.

Extended reading: Insertion Ultrasonic Water Flow Meter – Designed for Agricultural Irrigation, Garden Management

How does the ultrasonic flowmeter realize bidirectional flow measurement?

The principle of the ultrasonic flowmeter is to calculate the fluid flow rate using the difference in sound velocity. And multiply the fluid velocity by the area to calculate the volume flow.

Usually, there is an incident angle between the probe of the ultrasonic flowmeter, that is, the transducer and the meter body. From 60 degrees to 45 degrees. Ultrasonic waves propagate between a pair of probes if there is no fluid, that is, at zero flow. The travel time back and forth is the same. It is equivalent to a zero flow rate.

Extended reading: Ultrasonic Flow Meters Types & Technical Guide

Once there is fluid, the speed of the ultrasonic flowmeter back and forth between a pair of probes is different. Regardless of the direction of fluid flow, there will be a difference in sound velocity. If one direction is set as the normal flow direction, then the normal sound velocity should be a positive number. If the sound velocity difference is negative, the flow is in the opposite direction. That is reverse measurement. The measurement accuracy of the two directions is the same.

Extended Reading: Inline Ultrasonic Flow Meter

Can a vortex flowmeter measure bidirectional flow?

You cannot measure bidirectional flow with just one vortex flowmeter. But in some applications, you can use two for this.

The vortex flowmeter has a bluff body in front of the sensor, which is used to generate the vortex in the flow. As far as I know, no flowmeter has two bluff bodies to measure bidirectional flow.

If you have a two-way steam application. Then you can install two vortex flowmeters in the same line, as long as you respect the inlet and outlet operation of both. However, depending on the size of the line, this setting may become expensive.

Read more General-purpose Flow Totalizer for Data collection and calculation

Bidirectional orifice flowmeter

The bidirectional orifice flowmeter is a differential pressure flowmeter. Mainly used for flow measurement of liquid and gas. According to the characteristics of the orifice flowmeter, it has the advantage of high temperature and high pressure. Therefore, the orifice flowmeter is widely used in the field of high temperature and high-pressure measurement. The orifice flowmeter has high accuracy and good stability and is unanimously recognized by users.

What kind of measurement conditions will use an orifice flowmeter to measure? It can be used according to the requirements of the site, such as typical boiler steam, the general temperature can be close to about 500 degrees, and general flow meters cannot be used. However, the orifice flowmeter can effectively solve this high-temperature working condition, and the only disadvantage is its high cost of use.

Extended reading: 2 inch Water Flow Meter

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Sino-Inst offers over 50 flow meters for flow measurement. About 50% of these are differential pressure flow meters, 40% are the liquid flow sensor, and 20% are Ultrasonic Level Transmitter and mass flow meters.

A wide variety of flow meters options are available to you, such as free samples, paid samples.

Sino-Instrument is a globally recognized supplier and manufacturer of flow measurement instrumentation, located in China.

What does SCADA stands for?

What does SCADA stand for?

SCADA is the abbreviation of Supervisory Control And Data Acquisition. Namely data acquisition and monitoring control system. SCADA system is also called monitoring configuration software, which is widely used in enterprise equipment management of equipment automatic operation.

What is a SCADA system?

SCADA is a data acquisition and monitoring control system. The scada system is a computer-based production process control and scheduling automation system. It can monitor and control the operating equipment on site. Because each application field has different requirements for scada, the development of scada system in different application fields is not exactly the same.

The scada system is the most widely used in the power system, and the technology development is also the most mature. It is one of the most important subsystems of the energy management system (EMS system). It has the advantages of complete information, improved efficiency, correct control of system operation status, accelerated decision-making, and can help quickly diagnose system fault status. Now it has become an indispensable power dispatcher. Missing tools.

The scada system plays an irreplaceable role in improving the reliability, safety and economic benefits of power grid operation, realizing the automation and modernization of power dispatching, and improving the efficiency and level of dispatching.

How does SCADA work?

The SCADA system deploys multiple software and hardware elements, allowing industrial organizations to: monitor, collect and process data.

Connect and control machines and equipment such as valves, pumps, motors, etc. through HMI (Human Machine Interface) software.

Log the event to a log file.

In the basic SCADA architecture, sensor or manual input information is sent to PLC (Programmable Logic Controller) or RTU (Remote Terminal Unit), and then sent to a computer with SCADA software.

SCADA software analyzes and displays data to help operators and other workers reduce waste and improve the efficiency of the manufacturing process.

An effective SCADA system can greatly save time and money. Many case studies have been published, highlighting the benefits and savings of using modern SCADA software solutions such as ignition.

What is SCADA used for?

The SCADA system has a wide range of applications, and it can be used in the fields of data acquisition, monitoring and control and process control in electric power, metallurgy, petroleum, chemical, gas, railway and other industries. Its functions mainly focus on four aspects: real-time collection of production data, process monitoring of production equipment, abnormal alarms of production equipment, data analysis, data reports and dashboard display. Its characteristics mainly reflect the following aspects.

  1. It supports more than 5000 communication protocols and meets the communication requirements of 99.99% of controllers and instruments on the market. Get through the automated hardware system and the information transmission of the information software system.
  2. Isolate office network IP and industrial equipment IP in hardware to avoid IP conflicts.
  3. Intuitive display of production dynamics, direct or indirect control of on-site equipment, to meet the needs of visual management.
  4. Perform statistical analysis of data and display it through the dashboard.

The SCADA system is centered on the data collected in the production process. It is related to the distribution of people, machines, materials, methods, environments, testing, and R&D. It is based on the data generated during the operation of production equipment. It is also a big Most companies are most concerned about.

Secondly, the SCADA system is aimed at the application needs of the above-mentioned manufacturing enterprises. At the same time, it will give play to its own unique advantages to bring improvements and benefits to the enterprise.

  1. Help companies collect all kinds of data in the production process in real time. Instead of manual operations, it also avoids certain losses caused by personnel errors. Not only improves work efficiency, but also enables real-time monitoring of production All abnormal data in the process provides another layer of guarantee for the quality of the product.
  2. The SCADA system provides the production data of each device, which makes the production situation intuitive and clear, and facilitates the analysis of the production situation by the management personnel of the enterprise, and at the same time helps the enterprise optimize the production, making the production plan more scientific and reasonable.
  3. Realize the digital and intelligent improvement of the management process of products, production schedule, production efficiency, quality information, equipment operation, etc., and optimize the digital management and control capabilities of the production process.
  4. During the company’s external publicity and visit, the company’s image and professionalism will be improved by explaining the application and advantages of the system for the company.

Extended reading: PID Controller Working Principle

The difference between SCADA, DCS and PLC

SCADA and DCS are a concept, and PLC is a product, the three are not comparable:

  1. PLC is a product, which can form SCADA, DCS;
  2. DCS is developed from process control, and PLC is developed from relay-logic control system;
  3. PLC is equipment, DCS and SCADA are systems.

In a narrow sense, DCS is mainly used for process automation. PLC is mainly used for factory automation (production line). SCADA is mainly used for wide-area needs. Such as oil fields, which stretch for thousands of miles of pipelines.

If they are unified from the perspective of computers and networks, the main reason for the differences lies in the application requirements. DCS often requires advanced control algorithms.

For example, in the oil refining industry, PLC requires high processing speed. Because it is often used in interlocking, even fail-safe systems. SCADA also has some special requirements. Such as vibration monitoring, flow calculation, peak and valley adjustment, and so on.

Therefore, you can simply think:

  • SCADA is the dispatch management layer
  • DCS is the plant management
  • PLC is the field device layer

Sino-Inst offers over controllers for Industrial data recording and analysis.

It is widely used in hydropower, tap water, petroleum, chemical, machinery, hydraulic and other industries to measure, display and control the pressure of fluid media on site.

A wide variety of controllers are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of controllers, located in China.

What is Modbus Protocol?

What is meant by Modbus protocol?

Modbus Protocol is a serial communication protocol, which was published by Modicon company (now Schneider Electric) in 1979 for the use of programmable logic controller (PLC) communication. Modbus has become the industry standard (De facto) of communication protocols in the industrial field and is now a common connection method between industrial electronic devices.

Modbus Protocol Features

The main reasons why Modbus is more widely used than other communication protocols are:

  • Published publicly and without copyright requirements
  • Easy to deploy and maintain
  • For suppliers, there are not many restrictions on modifying mobile local bits or bytes

Modbus allows multiple (approximately 240) devices to be connected on the same network to communicate. For example, a device that measures temperature and humidity and sends the results to a computer. In the data acquisition and monitoring control system (SCADA), Modbus is usually used to connect the monitoring computer and the remote terminal control system (RTU).

How does a Modbus work?

Modbus is a master/slave communication mode with a single master station. There can only be one master station on the Modbus network, and the master station has no address on the Modbus network. The address range of the slave station is 0-247, where 0 is the broadcast address. The actual address range of the slave station is 1-247. Modbus communication standard protocol can be transmitted through various transmission methods, such as RS232C, RS485, optical fiber, radio, etc.

Modbus has two serial transmission modes, ASCII and RTU. They define different ways of how data is packaged and decoded. Devices that support Modbus protocol generally support the RTU format. Both communication parties must support one of the above modes at the same time.

The above is the official definition, let’s use ordinary words to explain:

This is actually the communication protocol, and any protocol is similar. There are only two communication formats and communication specifications.

If you want, you can also define a communication specification yourself. Use PLC or VB language to process according to this specification defined by yourself. If the reliability exceeds Modbus, then your communication specification is the most popular!

The difference and connection between RS 485 and MODBUS

I often see RS485 and MODBUS written together, and Sino-Inst will talk to you about the difference and connection between RS485 and MODBUS.

RS485 is a physical interface, which is simply hardware.

MODBUS is an international standard communication protocol used to exchange data between devices of different manufacturers (usually for industrial purposes); the so-called protocol can also be understood as the “language” someone said above, or simply software.

Under normal circumstances, two devices transmit data through the MODBUS protocol: RS232C was first used as the hardware interface, (that is, the serial communication port (serial port) on an ordinary computer). There is also RS422, and there is also commonly used RS485. This interface The transmission distance is long, and it is often used in general industrial scenes.

The MODBUS protocol is divided into three modes: MODBUS RTU, MODBUS ASCII and the later developed MODBUS TCP.

The physical hardware interfaces used by the first two (MODBUS RTU, MODBUS ASCII) are serial (Serial) communication ports (RS232, RS422, RS485).

And MODBUS TCP is to conform to the development trend of the world today. Anything can be connected by Ethernet or Internet to transmit data.

The hardware interface of MODBUS TCP mode is the Ethernet (Ethernet) port, which is the network port generally used on our computer.

We categorize industrial networks into three categories: RS485 network, HART network and fieldbus network.

HART network

HART is a transitional bus standard proposed by Emerson. It mainly superimposes a digital signal on top of a 4-20 mA current signal.

The physical layer uses BELL202 frequency shift keying technology. In order to realize the functions of some smart meters. But this agreement is not a truly open standard, and you have to join his foundation to get the agreement. Part of the cost of joining the foundation.

The technology is mainly monopolized by several large foreign companies, and in the past two years, some domestic companies have started to do it again. But it has not yet reached the level of foreign companies.

Nowadays, a large part of smart meters are equipped with HART round cards and all have HART communication function.

But from the domestic point of view, this part of the function has not been really used, at most it is only used to set the parameters of the handheld communicator. The HART intelligent instrument has not played its due function, and it has not been connected to the Internet for equipment monitoring.

In the long run, due to the low communication rate of HART, the networking is difficult and other reasons. The procurement volume of HART instruments will experience a downward trend.

However, because HART instruments have a history of more than ten years, the number of instruments installed is very large. For some system integrators, there is still a lot of room for use.

Fieldbus network

Fieldbus technology is one of the hotspots of technology development in the field of automation today. Known as the computer local area network in the field of automation. Its appearance marks the beginning of a new era of automation control technology.

Fieldbus is a digital, serial, multi-station communication network that connects the instruments installed in the control site and the control equipment installed in the control room. The key symbol is the ability to support bidirectional, multi-node, bus-style all-digital communication.

In recent years, fieldbus technology has become a hot spot in the development of automation and instrumentation in the world. The appearance of the fieldbus network is a revolutionary change in the traditional control system structure. It is the automatic control system that is moving in the direction of intelligence, digitization, informationization, networking, and decentralization. Form a new type of network integrated fully distributed control system-Fieldbus Control System FCS (Fieldbus Control System).

However, various standards of current fieldbus exist in parallel and have their own areas of survival. There has not yet been a truly unified standard. The key is that we cannot see when a unified standard will be formed, and the technology is not mature enough.

In addition, the types of fieldbus instruments are still relatively small, and the room for selection is small, and the price is relatively high. From the perspective of end users, most of them are still on the sidelines. I want to wait until the technology is mature and consider it, but now there are few implementations.

RS485 network

RS485/MODBUS is a popular way of network layout. Its characteristic is simple and convenient to implement. And now there are many instruments that support RS485, especially in the oil industry.

RS485/MODBUS is simply dominating the world. Current instrument vendors have also switched to support RS485/MODBUS. The reason is simple, like the original HART instrument, it is very difficult and expensive to buy a conversion port. The RS485 conversion interface is much cheaper and has a wide variety.

At least in the low-end market, RS485/MODBUS will still be the most important networking method, and it will not change in the past two to three years.

Features of 4-20mA current loop and RS485 communication (Modbus RTU protocol) data acquisition

4-20mA current loop data acquisition characteristics

Use pressure, temperature transmitter and current acquisition module (RTU) or acquisition card on site for data acquisition and then communicate and transmit with the industrial computer. The data acquisition system using 4-20mA current loop instrument has the following characteristics:

  1. The construction is complicated, data cables need to be buried in advance, the number of cables is large, and the construction period is long
  2. The computer terminal needs a current acquisition card or a data acquisition module
  3. Complicated replacement and maintenance operations, troublesome expansion
  4. 4-20mA current loop data acquisition accuracy is low, and the error comes from 4-20mA output instrument and acquisition card (or data acquisition module)

RS485 communication (Modbus protocol) data acquisition characteristics

Use smart meters, transmitters, actuators, etc. with RS485 communication to directly communicate with the serial port of the industrial computer. The use of RS485 communication digital sensor meter network system has the following characteristics:

  1. The construction complexity is reduced, data cables need to be buried in advance, the number of cables is small, and the construction period is reduced
  2. The computer terminal only needs an isolated RS485/RS232 converter
  3. Easy to replace and maintain, and easy to expand
  4. High acquisition accuracy, eliminating the error of RTU, the system error only comes from the transmitter itself
  5. RS485 communication has good transmission stability and less network maintenance
  6. The cost of use is greatly reduced|
  7. The maximum communication distance of RS485 is 1200 meters

RS485 communication transmission of electromagnetic flowmeter Modbus protocol

The RS485 communication data transmission interface of the electromagnetic flowmeter is half-duplex. The standard rate is greater than 250kHz. The communication direction conversion time is 3.5us. Usually 16-way load can be connected. It can also be expanded to 32 channels. Standard shielded twisted pair cable is 1000m. Use master-slave multi-machine communication. When multiple electromagnetic flowmeters are interconnected. It can save signal lines and facilitate high-speed transmission.

RS-485 communication has good anti-noise interference. Long transmission distance and multi-station capability. Will not affect the synchronization of on-site and remote data due to PLC failure.

However, the electromagnetic flowmeter must have a 485 interface and support the MODBUS RTU protocol.

In order to maintain stability, it is better to use electromagnetic flowmeters of the same manufacturer and the same brand when communicating with multiple flowmeters.

RS485 is a kind of industrial data bus. The electromagnetic flowmeter has RS485 serial communication so that digital communication replaces the transmission of PLC analog signals and ordinary switch signals. The PLC simulation calculation is reduced, and the accurate data collection and transmission are realized.

RS485 precession vortex flowmeter

Precession vortex flowmeter is a new type of gas flowmeter. It can be used for the measurement of natural gas, propane, air, nitrogen and other gases.

The converter can output frequency pulse, 4 ~ 20mA analog signal, and has RS485 interface, can be directly connected to the computer network, transmission distance up to 1.2km;

Precession Vortex Gas Flowmeter, like vortex flowmeter, is a velocity flowmeter. The cost performance of the intelligent precession vortex flowmeter is higher than vortex flowmeter. The intelligent precession vortex flowmeter can only measure gas. Precession Vortex Gas Flowmeter can be made into an integrated temperature and pressure compensation. And can measure various gases. Such as compressed air, oxygen, biogas, natural gas, coal gas, etc.

Read more about Everything You Need To Know About Electronic Flow Meters

Guide: Magnetic Flowmeter Installation

Magnetic flowmeters are mainly used to measure the flow of conductive media with good fluidity. Magnetic flowmeters are divided into insertion type and pipeline type. Pipeline electromagnetic flowmeter and insertion electromagnetic flowmeter has the same requirements for installation. There are also different places. Generally speaking, there are requirements for the external environment and installation methods.

A magnetic Flow Meter is a flow meter that measures the flow of conductive fluids. Abbreviated as EMF, also called Electromagnetic flowmeters. It is a kind of Volumetric flow meter. A magnetic flow meter measures the velocity of conductive liquids moving through a pipe or conduit. In the wastewater treatment industry, a Magnetic Flow Meter is the best flow meter choice.

Electromagnetic flowmeters have been used for more than 50 years and have been widely used worldwide. The fields involve water/sewage, chemical, pharmaceutical, paper, food, and other industries.

  • Water / Wastewater Industry
  • Food and Beverage
  • Metals
  • Brewing, Distilling, and Wine makening
  • HVAC
  • Chemical
  • Pulp and Paper
  • Pharmaceutical
  • Mining, Mineral Processing

Extended reading: How to Select the Right Agriculture Flow Meter

Magnetic flowmeters use the principle of Faraday’s Law of Electromagnetic Induction to measure the flow rate of liquid in a pipe. In the magnetic flowmeter pipe parts, a magnetic field is generated and channeled into the liquid flowing through the pipe. 

Faraday’s Law states that the voltage generated is proportional to the movement of the flowing liquid. A conductor moving through a magnetic field produces an electric signal within the conductor. And the singal is proportional to the velocity of the water moving through the field. 

As fluid flows through the magnetic field, conductive particles in the fluid create changes. This variation is used to measure and calculate the velocity of water flow through the pipe. When the fluid moves faster, more voltage is generated. The electronic transmitter processes the voltage signal to determine the liquid flow.

To learn more about Magnetic Flow Meters, this video by Emerson gives a good explanation.
Video source: https://www.youtube.com/watch?reload=9&v=lRSjYjg9WRo

Read more about Everything You Need To Know About Electronic Flow Meters

The premise of using an electromagnetic flowmeter is that the liquid to be measured must be conductive and cannot be lower than the threshold (ie, the lower limit). If the conductivity is lower than the threshold value, measurement errors will occur until it cannot be used. The threshold value of general-purpose electromagnetic flowmeters is between 10-4~(5×10-6)S/cm, depending on the model. The general conductivity threshold is 5×10-6S/cm=5μS/cm. the

The conductivity of industrial water and its aqueous solution is greater than 10-4S/cm. The conductivity of acid, alkali and salt solution is between 10-4 and 10-1S/cm. There is no problem in use, and the low-grade distilled water is 10-5S/cm cm is also not a problem.

Petroleum products and organic solvents cannot be used if their conductivity is too low.

Some pure liquids or aqueous solutions have low conductivity and are considered unusable. However, in the actual work of electromagnetic flowmeters, there will be instances where they can be used because they contain impurities, which are beneficial to increase the conductivity.

For the aqueous solution, the conductivity in the data is measured in the laboratory with pure water. The actual aqueous solution may be mixed with industrial water. The conductivity will be higher than that found. It is also conducive to flow measurement.

Step 1: Magnetic Flowmeter Installation environment requirements

In order to make the electromagnetic flowmeter work stable and reliable, the following requirements should be paid attention to when choosing the installation location:

  1. Try to avoid ferromagnetic objects and equipment with strong electromagnetic fields (large motors, large transformers, etc.). In order to prevent the magnetic field from affecting the working magnetic field and flow signal of the sensor.
  2. Install in a dry and ventilated place as much as possible. Avoid sun and rain. The ambient temperature should be -20 ~ +60 ℃. The relative humidity is less than 85%.
  3. There should be ample space around the flowmeter. Easy to install and maintain.

Extended reading: Ultrasonic Insertion Flow Meter for Lined/Large Pipes

Step 2: Magnetic Flowmeter Installation Location selection

The electromagnetic flowmeter can be installed on a horizontal pipe or a vertical pipe.

  1. Choose a straight pipe section filled with liquid, such as the vertical section of the pipeline (flow direction from bottom to top is appropriate) or a liquid-filled horizontal pipe (the lowest point in the entire pipeline is appropriate). The position must ensure that the pipeline is always filled with the measured fluid . In the process of installation and measurement, there must be no partial full pipe.
  2. Select the place where the fluid flow pulse is small. That is, it should be far away from pumps, valves, elbows and other local resistance parts.
  3. When measuring two-phase (solid, liquid or gas, liquid) fluids, choose a place that is not easy to cause phase separation.
  4. Avoid negative pressure at the measurement site.
  5. The diameter or circumference of the side pipe is easy to measure, and the ovality should be small.
  6. Straight pipe length: The length of the straight pipe on the upstream side of the sensor installation pipeline should be greater than or equal to 10D, and the downstream side should be no less than 5D.
  7. There are two methods for inserting the insertion point of the plug-in electromagnetic flow sensor: one is to insert it on the central axis of the pipe under test, and the other is to insert it at 0.25D where the inner wall of the pipe is the pipe.
  8. Vertical installation: when the sensor is inserted into the pipe, the angle between the vertical diameter of the pipe section and the pipe section should be less than 5°, which is suitable for measuring clean media with small pipe vibration.
  9. Tilt installation: the angle between the axis of the sensor and the axis of the pipeline being measured is 45°. It is suitable for liquid flow measurement with large pipe diameter and other impurities in the measuring medium. This installation method has low water resistance and is not suitable for entanglement.

Step 3: Mounting flange for Magnetic Flowmeter Installation

A. Select the installation location and select the front and rear straight pipe sections of appropriate length. Cut the pipe section where the flowmeter is installed;
B. Weld a flange on each of the front and rear straight pipe sections. After adding gaskets at both ends of the sensor, connect the sensor to the flange with stud bolts (note that the direction of the arrow on the meter body should be consistent with the direction of fluid flow);
C. Weld the front and rear straight pipe sections of the sensor to the original pipe.

Note:

  1. When welding, ensure that the flange end face is perpendicular to the centerline of the pipeline;
  2. The place where the mounting hole pitch is larger is the meter rod mounting position. And the direction of the mounting holes of the two flanges should be the same;
  3. After the flange is welded, the pipeline should be cleaned up and there should be no welding slag and other sundries.

Extended reading: Magnetic Large Dia. Pipe Flow Meter

Step 4: Converter installation and connection cables

Power and signal wiring. Please refer to the product manual accompanying the goods.

The converter of the split electromagnetic flowmeter should be installed near the sensor where it is convenient for reading and maintenance. It can also be installed in the instrument room, and its environmental conditions can be much better than the sensor.

The distance between the converter and the sensor is limited by the conductivity of the measured medium and the signal of the signal cable. That is, the distributed capacitance of the cable, the cross-section of the wire, and the number of shielding layers. Use the information cable provided with the instrument by the manufacturer.

For liquids with lower conductivity and longer transmission distances, three-layer shielded cables are also specified.

The general instrument “Instruction Manual” gives the corresponding transmission distance range for liquids with different conductivity.

When a single-layer shielded cable is used for industrial water or acid-base liquids, the transmission distance is usually 100m.

In order to avoid signal interference, the signal cable must be worn separately in a well-grounded steel protection tube. Never put the signal cable and the power cord in the same steel pipe.

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Special Magnetic Flowmeter Installation situation

For pipelines that do not allow flow interruption in the process, a bypass pipe should be installed and cleaned when the flow meter is installed. As shown in the figure, this device ensures continuous operation of the equipment system when the flow meter is withdrawn from use.

The inner diameter measured by the flowmeter should be consistent with the inner diameter of the pipe. If the inner diameter cannot be the same, the inner diameter of the pipe should be greater than the inner diameter of the flowmeter. And install a tapered tube or expansion tube with a cone angle not greater than 15 between them, as shown in the figure.

When the flowmeter is installed inclined or vertically, the flow direction should be from top to bottom, as shown in the figure.

All Magnetic Flowmeter Installations. It cannot be described in detail here. If you encounter problems with the Magnetic Flowmeter Installation. Please contact our engineers in time. We will guide the Magnetic Flowmeter Installation for you.

Featured Magnetic Flowmeters for Sale

Frequently
Asked
Questions

Generally speaking, there will be an indication of the fluid flow direction on the main body of various flowmeters. When we install the flowmeter, just follow the instructions to install it.

Generally speaking, there are two principles for the installation direction of the flowmeter.

  1. Make sure to measure full of fluid. Because absolutely most of the flowmeters need to be in a full pipe state to ensure the measurement effect.
  2. Install according to the instructions of the flowmeter.

Electromagnetic flowmeters can be installed vertically. However, vertical installation needs to pay attention to the following aspects, whether it is installed at the water inlet or the water outlet. Standard installed in the middle of the vertical position where the water flows upwards. This installation complies with gravity.

If it is installed downstream, it will not be a full pipe, and the water flow from bottom to top is always full. This facilitates accurate measurement of the flow meter. The straight pipe section is required to be 10D in front and 5D in back to ensure the use and accuracy requirements of the electromagnetic flowmeter.

Electromagnetic flowmeter vertical installation requirements:

  1. Installed at the inlet of the pipeline (that is, upstream), so that the pipeline is always full.
  2. The electromagnetic flowmeter should be installed in the lower part of the horizontal pipeline, vertically upward. Avoid installing at high places and vertically downward positions in the pipeline.
  3. Requirements for straight pipe section: inlet/outlet straight pipe section: inlet ≥ 10×DN; water outlet ≥ 5×DN
  4. In order to facilitate the detection of the flowmeter, a bypass channel is set in the measuring pipeline.
  5. Grounding point requirements: In order to make the instrument work reliably, improve the measurement accuracy, and not be disturbed by strong external electromagnetic fields, the sensor should be well grounded, and the grounding resistance should be less than 10 ohms.

Generally speaking, there is no other cost to install a flow meter.
However, the actual situation needs to be determined according to the user’s pipeline situation.

The pump outlet flow meter should be installed after the pump outlet valve. But before regulating the valve. In this way, the regulating valve will not affect the measurement of the flowmeter.

The flowmeter is not allowed to be installed in front of the pump, because there will be negative pressure in front of the pump, which will affect the accuracy of the electromagnetic flowmeter. Therefore, the electromagnetic flowmeter must be installed behind the pump.

The installation distance depends on the length and width of your pipeline, and the flowmeter has certain requirements for the straight pipe sections before and after it. At least the straight pipe section in front of the flowmeter is 10 times the diameter of the flowmeter. The straight pipe section behind the flowmeter is 5 times the diameter of the flowmeter. The farther away from the straight pipe, the better.

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Sino-Inst offer over 50 Magnetic Flow Meters, with Best Price.

A wide variety of Magnetic Flow Meters options are available to you, such as free samples, paid samples.

About 13% of these are magnetic flow meter, 14% are Insertion Magnetic Flow Meter, 25% are Venturi flow meter, 13% are ultrasonic flow meter, and others are Liquid Turbine Flow Meters.

Electromagnetic flowmeters can be divided into insertion electromagnetic flowmeters and pipeline electromagnetic flowmeters. The Magnetic Flowmeter Installation methods of insertion electromagnetic flowmeters and pipeline electromagnetic flowmeters have the same place, but there are also differences.

First of all, what we need is that the shielded wire of the electromagnetic flowmeter cannot be routed together with the cable, because this will cause interference. Under normal circumstances, the parameters of the inner head of the electromagnetic flowmeter are set in advance, so no other adjustments are required.

Magnetic Flowmeter Installation should avoid places where the temperature rises and falls too much, and places where there are magnetic fields and strong vibration sources.

Sino-Inst is Magnetic Flow Meters supplier, located in China. Magnetic Flow Meters products are most popular in North America, Mid East, and Eastern Europe. The United States, and India, which export 99%, 1%, and 1% of Magnetic Flow Meters respectively.

For how to install the electromagnetic flowmeter, the details of Magnetic Flowmeter Installation, if you have any questions and ideas, please feel free to contact us.

Solvent flow meters

The solvent flow meter is a flow meter that can measure solvent volume or mass flow. In the industrial production process, it is very important to accurately measure the amount of solvent. Solvents are divided into organic solvents and inorganic solvents according to their chemical composition. Solvents are commonly used raw materials in various industries such as coatings, paints, and dyes.

Solvent refers to a substance that can dissolve other solids, liquids, gases, and other solutes. The most common solvent in our daily lives is water. Generally, the solvent has a low boiling point and is easy to volatilize, and the solvent cannot produce a chemical reaction to the solute. Solvents are generally colorless and transparent liquids with unique odors.

Solvents play a very important role in adhesives.

Organic solvents are a large class of organic compounds that are widely used in life and production. They have a small molecular weight and are liquid at room temperature. Organic solvents include many types of substances, such as paraffin, alkenes, alcohols, aldehydes, amines, esters, ethers, ketones, aromatic hydrocarbons, hydrogenated hydrocarbons, terpene olefins, halogenated hydrocarbons, heterocyclic compounds, nitrogen-containing compounds, and sulfur-containing compounds, etc. Etc. Most of them are toxic to the human body.

Solvents are generally found in paints, adhesives, lacquers, and cleaners. Commonly used organic solvents include DMF, cyclohexanone, acetonitrile, acetic acid, methyl acetate, ethyl acetate, isopropanol, vinyl acetate, cyclohexane, n-hexane, n-heptane, etc.

Organic solvents are a class of organic compounds that can dissolve some water-insoluble substances (such as grease, wax, resin, rubber, dyes, etc.). Its characteristic is that it is liquid at room temperature and pressure. It has greater volatility. In dissolution During the process, the properties of the solute and solvent are unchanged.

There are many types of organic solvents, which can be divided into 10 categories according to their chemical structure:

①Aromatic hydrocarbons: benzene, toluene, xylene, etc.;
②Aliphatic hydrocarbons: pentane, hexane, octane, etc.;
③ Alicyclic hydrocarbons: cyclohexane, cyclohexanone, toluene cyclohexanone, etc.;
④ Halogenated hydrocarbons: chlorobenzene, dichlorobenzene, dichloromethane, etc.;
⑤Alcohols: methanol, ethanol, isopropanol, etc.;
⑥Ethers: ether, propylene oxide, etc.;
⑦Esters: methyl acetate, ethyl acetate, propyl acetate, etc.;
⑧ Ketones: acetone, methyl butanone, methyl isobutyl ketone, etc.;
⑨Diol derivatives: ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, etc.;
⑩Others: acetonitrile, pyridine, phenol, etc.

Read More about: Chemical Flow Meter Guide

Solvent flow meter – Oval Gear

An Oval Gear flowmeter as a mechanical flow meter is a common type of Volumetric Flow Meter. It can measure the volume flow of high viscosity and corrosive Solvent fluids.

  • High measurement accuracy;
  • The installation pipeline conditions have no influence on the measurement accuracy;
  • Can be used for high-viscosity liquids;
  • Wide range;
  • The direct-reading meter can directly obtain the cumulative and total amount without external energy.
  • Clear and clear, easy to operate.

Extended reading: Mechanical flow meter types

Solvent flow meter – Turbine

Turbine flow meters are velocity flow meters, also called impeller flow meters. Can be used to measure the instantaneous flow and cumulative flow of Solvent liquids.

Turbine flowmeters are widely used in flow measurement: petroleum, organic liquids, inorganic liquids, liquefied gas, natural gas, coal gas and cryogenic fluids. Turbine flowmeter signals can be divided into pulse signals or current signals (4-20mA). It is suitable for use with secondary display, PLC, DCS and other computer control systems.

Turbine Flow Meter reference price: USD 200-1700/pc.

Extended reading: non contact flow meter

Solvent flow meter – Electromagnetic

Magnetic Flow Meter is a flow meter that measures the flow of conductive Solvent fluids. Abbreviated as EMF, also called Electromagnetic flowmeters. It is a kind of Volumetric flow meter. A magnetic flow meter measures the velocity of conductive liquids moving through a pipe or conduit. In the wastewater treatment industry, Magnetic Flow Meter is the best flow meter choice.

  • Measures liquids or liquid slurries that have a minimum conductivity of 5 µS/cm.
  • Sanitary type, PTFE anticorrosive materials are optional.
  • Clamps, flanges, insertion installation are optional.
  • Battery powered optional.
  • Low cost.
  • DN 6 to DN2000
  • High precision: 0.5%, 0.2% optional

Extended reading: How to Select the Right Agriculture Flow Meter

Solvent flow meter – Gear

Gear flow meter is a micro digital positive displacement flow meter. Can measure very small flow rates and quantify small volumes of liquid. High and low-temperature resistance (-196℃-200℃).

The Gear flow meter for Microflow is made of stainless steel and is used for precise continuous or intermittent measurement of the flow or instantaneous flow of liquid. It is especially suitable for the flow measurement of heavy oil, polyvinyl alcohol, grease, and other high-viscosity media. It can measure the viscosity of Fluid up to 10000Pa.s.

Generally speaking, we can choose a suitable flow meter according to the different characteristics of chemical solvents. For example, high-viscosity solvents are recommended to use gear flow meters. For example, for corrosive solvents, electromagnetic flowmeters can be used. If you need to reduce costs, you can choose a turbine flowmeter.

Of course, it needs to be based on our actual measurement conditions, such as the temperature of the medium, the temperature of the pipeline, the pressure, and so on. Select the appropriate flow meter to achieve accurate measurement.

Extended reading: Cylinder Gear flow meter for micro flow measurement.

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Sino-Inst, Manufacuturer for Solvent flow meters.

Sino-Inst’s Solvent flow meters, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, US, and other countries.

RTD vs Thermocouple

RTD vs Thermocouple- What is the difference? What are they used for?

Both RTDs and thermocouples are sensors used to measure heat such as Fahrenheit and Kelvin. Both thermocouple and thermal resistance belong to contact temperature measurement in temperature measurement. Although its role is to measure the temperature of the object the same. But their working principles and characteristics are different. Thermocouple is the most widely used temperature device in temperature measurement. Thermal resistance does not require compensation wires and is cheaper than thermocouples.

As two major contact temperature sensors: thermocouple and thermal resistance. Their names differ by only one word and both can be used as sensors for measuring object temperature.

The choice of thermocouple or thermal resistance should be judged according to the measured object environment. Many people are not sure what to choose. Therefore, it is necessary to fully understand the difference between thermal resistance and thermocouple temperature sensor when choosing a temperature sensor.

RTDs stands for ‘Resistance Temperature Detectors’

Thermal resistance: no compensation wire is needed, the price is cheaper

The principle of temperature measurement of thermal resistance: based on the characteristics of the resistance of conductors or semiconductors that change with temperature.

Thermal resistance is one of the most commonly used temperature detectors in medium and low-temperature areas. The thermal resistance temperature measurement is based on the characteristic that the resistance value of the metal conductor increases with the increase in temperature for temperature measurement.

The advantage of thermal resistance: It can also transmit electrical signals remotely. High sensitivity and strong stability. Interchangeability and accuracy are better. However, power supply excitation is required. The temperature change cannot be measured instantaneously.

Disadvantages of thermal resistance: Although thermal resistance is widely used in industry. But because of his temperature measurement range, his application has been limited.

Industrial thermal resistance generally uses Pt100, Pt10, Cu50, Cu100, the temperature range of platinum thermal resistance is generally minus 200-800 degrees Celsius, and copper thermal resistance is minus 40 to 140 degrees Celsius.

Thermal resistors are mostly made of pure metal materials. At present, platinum and copper are the most widely used. In addition, materials such as nickel, manganese, and rhodium have now been used to make thermal resistors.

Thermal resistance does not require compensation wires and is cheaper than thermocouples.

Thermocouple: can transmit 4-20mA electrical signal far away

Thermocouple temperature measurement principle:

The principle of thermocouple temperature measurement is based on the thermoelectric effect. Connect two different conductors or semiconductors into a closed loop. When the temperature at the two junctions is different. The thermoelectric potential will be generated in the loop. This phenomenon is called the thermoelectric effect, also known as the Seebeck effect.

The thermoelectric potential generated in the closed-loop is composed of two kinds of electric potential. Thermoelectric potential and contact potential.

Thermoelectric potential refers to the electric potential generated by the temperature difference between the two ends of the same conductor.

Different conductors have different electron densities, so they generate different electric potentials.

The contact potential, as the name implies, refers to when two different conductors are in contact. Because their electron densities are different, a certain amount of electron diffusion occurs. The electric potential formed when they reach a certain equilibrium. The magnitude of the contact potential depends on the material properties of the two different conductors and the temperature of their contact points.

The advantages of thermocouples:
Wide temperature measurement range. The performance is relatively stable. At the same time, the structure is simple. The dynamic response is good. It can transmit 4-20mA electrical signals remotely. It is convenient for automatic control and centralized control.

Thermocouples currently used internationally have a standard specification. Internationally, thermocouples are divided into eight different divisions, namely B, R, S, K, N, E, J, and T. The lowest temperature can be measured at minus 270 degrees Celsius and the highest can reach 1800 degrees Celsius.

Among them, B, R, and S belong to the platinum series of thermocouples. Because platinum is a precious metal. So they are also called precious metal thermocouples and the remaining ones are called cheap metal thermocouples.

There are two types of thermocouples, common type, and armored type.

Ordinary thermocouples are generally composed of hot electrodes, insulating tubes, protective sleeves, and junction boxes. The armored thermocouple is a combination of thermocouple wire, insulating material, and a metal protective sleeve. A solid combination is formed by stretching.

But the electrical signal of the thermocouple needs a special wire to transmit, this kind of wire is called compensation wire.

Different thermocouples require different compensating wires, and their main function is to connect with the thermocouple to keep the reference end of the thermocouple away from the power supply so that the temperature of the reference end is stable.

Compensation wires are divided into two types: compensation type and extension type. The chemical composition of the extension wire is the same as that of the thermocouple being compensated. However, in practice, the extended wire is not made of the same metal as the thermocouple. Generally, a wire with the same electron density as the thermocouple is used instead.

The connection between the compensation wire and the thermocouple is generally very clear. The positive pole of the thermocouple is connected to the red wire of the compensation lead, and the negative pole is connected to the remaining color. Most of the general compensation wires are made of copper-nickel alloy.

Extended reading:  Tri Clamp Sanitary Thermometers

  1. Thermocouple English Thermocouple, abbreviated as TC, works on the principle of outputting a linear millivolt signal as the temperature changes. The instrument amplifies the signal and converts it into a temperature signal.
  2. Thermal resistance English Resistance abbreviation RTD working principle is: the resistance value changes linearly with temperature changes.
  3. The temperature transmitter can convert the thermocouple mV voltage signal or the resistance value signal of the thermal resistance into a 4-20mA standard signal for automation system control.
  4. Generally speaking, thermal resistance is cheaper than thermocouple.

Extended reading: RTD vs. Thermocouple: What’s the Difference, and Which Should You Use?

Here, we list some temperature measurement ranges of thermal resistance and thermocouple sensors, and the thermoelectric potential and thermal resistance values of 100°C.

Thermocouple

  • Platinum Guy 10-Platinum (Type S) (0-1300℃), T=100℃, E(100,0)=0.646mV.
  • Platinum Guy 13-Platinum (R type) (0-1300℃), T=100℃, E(100,0)=0.647mV.
  • Zhenming-Zhensi (K type) (0-1200℃) T=100℃E(100,0)=4.096mV.
  • Zhenming-Constantan (Type E) (-200-760℃), T=100℃, E(100,0)=6.319mV

Thermal resistance

  • Platinum thermal resistance (pt100) (-200-850℃), T=100℃, R=138.50Q
  • Copper thermal resistance, (Cu50) (-50-150℃), T=100℃, R=71.4Q.

RTD vs Thermocouple difference

A thermocouple is a sensor that measures temperature. It is a temperature sensor like a thermal resistance. But the main difference between thermocouple and thermal resistance lies in:

  1. The nature of the signal.

The thermal resistance itself is a resistance, and the change of temperature causes the resistance to produce a positive or negative resistance change; while a thermocouple produces a change in the induced voltage, which changes with the change of temperature.

  1. The temperature ranges detected by the two sensors are different.

The thermal resistance generally detects the temperature range of 0-150 degrees. The highest measurement range can reach about 600 degrees (of course, negative temperature can be detected).

The thermocouple can detect a temperature range of 0-1000 degrees (or even higher). Therefore, the former is low temperature detection, and the latter is high temperature detection.

  1. Different materials

From the material point of view, thermal resistance is a metal material. Metal materials with temperature-sensitive changes, thermocouples are bimetallic materials. Both two different metals.

Due to the change in temperature, a potential difference is generated at the two ends of two different metal wires.

  1. PLC modules are different

The thermal resistance corresponding to PLC and the input module of thermocouple are also different, this sentence is no problem. But generally PLC is directly connected to 4-20ma signal, and thermal resistance and thermocouple are generally equipped with transmitter before they are connected to PLC. If you connect to DCS, you don’t need to use a transmitter! The thermal resistance is the RTD signal, and the thermocouple is the TC signal!

  1. PLC also has thermal resistance module and thermocouple module, which can directly input thermal resistance and thermocouple signals.

6. Different prices

Thermocouples are available in J, T, N, K, S and other models. Some are more expensive than resistors, and some are cheaper than resistors. However, if the compensation wire is included, the comprehensive cost of the thermocouple is higher. Thermal resistance is a resistance signal, and thermocouple is a voltage signal.

  1. Different measurement principles

The principle of thermal resistance temperature measurement is based on the property of the resistance of the conductor (or semiconductor) that changes with temperature. The measurement range is minus 00 to 500 degrees. Commonly used are platinum resistance (Pt100, Pt10), copper resistance Cu50 (minus 50-150 degrees).

The principle of thermocouple temperature measurement is based on the thermoelectric effect to measure temperature. Commonly used are platinum rhodium-platinum (graduation number S, measuring range 0~1300 degrees), nickel chromium-nickel silicon (graduation number K, measuring range 0~900 degrees), nickel chromium-constantan (graduation number E, measuring range 0 to 600 degrees), platinum rhodium 30-platinum rhodium 6 (grading number B, measuring range 0 to 1600 degrees).

RTD vs Thermocouple, how to choose?

The selection of thermocouple should be based on comprehensive considerations such as the use temperature range, the required accuracy, the use atmosphere, the performance of the measurement object, the response time and the economic benefits.

  1. Selection of measurement accuracy and temperature measurement range
  • When the operating temperature is 1300~1800℃ and the accuracy is relatively high, the B-type thermocouple is generally used;
  • The accuracy is not high, and the atmosphere allows the use of tungsten rhenium thermocouples.
  • Tungsten rhenium thermocouple is generally used above 1800℃;
  • The operating temperature is 1000~1300℃, the accuracy is required and the high accuracy is available. S-type thermocouple and N-type thermocouple are available;
  • Generally use K-type thermocouple and N-type thermocouple below 1000℃;
  • Generally use E-type thermocouple below 400℃;
  • T-type thermocouples are generally used for measurement at 250°C and negative temperature. T-type thermocouples are stable and have high accuracy at low temperatures.
  1. The choice of atmosphere

S-type, B-type, and K-type thermocouples are suitable for use in strong oxidizing and weak reducing atmospheres. J-type and T-type thermocouples are suitable for weak oxidizing and reducing atmospheres. If a protective tube with better airtightness is used, the requirements for the atmosphere are not too strict.

  1. Choice of durability and thermal response

Thermocouples with larger wire diameters have better durability, but their response is slower. For thermocouples with large heat capacity, the response is slow. When measuring a temperature with a large gradient, in the case of temperature control, the temperature control is poor. It requires a fast response time and a certain degree of durability, so it is more appropriate to choose an armored couple.

  1. The nature and state of the measuring object to choose the thermocouple

The temperature measurement of moving objects, vibrating objects, and high-pressure vessels requires high mechanical strength. A chemically polluted atmosphere requires a protective tube. In the case of electrical interference, higher insulation is required.

Selection process: model-index number-explosion-proof grade-precision grade-installation and fixed form-protective tube material-length or insertion depth.

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Grease Flow Meters

What is a Grease Flow Meter?

Grease Flow meters are meters dedicated to measuring the volume or mass flow of industrial grease fluids.

The most common Grease Flow meters are elliptical gear flow meters, also called positive displacement flowmeters. There are turbine flow meters, gear flow meters, and so on. Industrial grease can be measured online. Including hydraulic oil, steam turbine oil, refrigeration oil, heat treatment oil and heat transfer oil, etc. In addition, there are greases with lubricating oil as base oil and thickening agent.

Industrial Grease Flow meters are different from grease guns or grease meters. Industrial Grease Flow meters need to deal with more complex conditions. The pipe diameter can range from DN10 to DN200, or even larger. So how to choose the applicable Industrial Grease Flow meters? Let’s analyze it together.

Characteristics of industrial grease

What are the types of industrial grease?

Industrial greases mainly include hydraulic oil, gear oil, turbine oil, compressor oil, refrigeration oil, transformer oil, vacuum pump oil, bearing oil, metal processing oil (liquid), anti-rust grease, cylinder oil, heat treatment oil, and heat transfer oil.

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In addition, there are greases with lubricating oil as base oil and thickening agent. The users of industrial lubricants are companies from all walks of life, and they use many varieties and large amounts.

The basic performance and main selection principle of industrial grease is viscosity. GB/T3141-94 is the ISO viscosity classification of industrial liquid lubricants, which is equivalent to the international standard ISO3448-1992 “Industrial Liquid Lubricants-ISO Viscosity Classification”.

So, when we choose an industrial grease flow meter, we first need to consider the viscosity of the grease. Then consider the flow range and temperature. And other special requirements of users.

Our commonly used industrial grease flow meters are oval gear flow meters, turbine flow meters, and gear flow meters. There is also a mass flow meter. Next, let’s discuss separately.

Grease Flow Meters-Oval Gear

Oval gear flowmeter is a volumetric meter for continuous or intermittent measurement and control of liquid flow in a pipeline.

Oval gear flowmeter, also known as positive displacement flowmeter. A positive displacement flowmeter as a mechanical flow meter is a common type of Volumetric Flow Meter. It can measure the volume flow of high viscosity and corrosive fluids.

  • Volumetric Flow Meters
  • High measurement accuracy;
  • The installation pipeline conditions have no influence on the measurement accuracy;
  • Can be used for high-viscosity liquids;
  • Wide range;
  • The direct-reading meter can directly obtain the cumulative and total amount without external energy.
  • Clear and clear, easy to operate.

Therefore, we recommend that when the grease viscosity is high, you can first consider using an oval gear flowmeter.
Viscosity: 0.6—2mPa.s—200mPa.s—1000mPa.s-2000mPa.s.
Temperature: -20~+200℃

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Grease Flow Meters-Turbine

Turbine flow meters are velocity flow meters, also called impeller flow meters. Can be used to measure the instantaneous flow and cumulative flow of liquids and gases.

Turbine flowmeters are widely used in flow measurement: petroleum, organic liquids, inorganic liquids, liquefied gas, natural gas, coal gas, and cryogenic fluids. Turbine flowmeter signals can be divided into pulse signals or current signals (4-20mA). It is suitable for use with secondary display, PLC, DCS, and other computer control systems.

Therefore, when measuring low-viscosity oils, such as diesel, edible oil, etc., we recommend that turbine flowmeters be considered first.

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Grease Flow Meters-Gear

Gear flow meter is a micro digital positive displacement flow meter. Can measure very small flow rates and quantify small volumes of liquid. High and low-temperature resistance (-196℃-200℃).

The Gear flow meter for Microflow is made of stainless steel and is used for precise continuous or intermittent measurement of the flow or instantaneous flow of liquid. It is especially suitable for the flow measurement of heavy oil, polyvinyl alcohol, grease, and other high-viscosity media. It can measure the viscosity of Fluid up to 10000Pa.s.

  • High pressure resistance (1.0-45MPa)
  • High and low temperature resistance (-196℃-200℃)
  • Can measure various viscous media
  • High precision and repeatability
  • Pulse output/analog output optional
  • Wide range ratio (1:100)
  • Wide measuring range
  • Strong anti-corrosion and anti-fouling ability (acid and alkali)

Therefore, it is recommended to use Gear flow meters, when you need to measure grease in the following situations:High viscosity, low flow rate;Ultra-high temperatureUltra-low temperature;Small caliber;high pressure.

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Grease Flow Meters-Mass

Mass flow meter directly measures the mass flow of the medium passing through the flow meter. It can also measure the density, temperature, and viscosity of the medium

Mass flow meter is a flow measuring instrument that measures the mass flow in the pipeline. The volume of a fluid is a function of fluid temperature and pressure and is a dependent variable. The quality of a fluid is a quantity that does not change with time, space temperature, and pressure. More about: What Is Mass Flow Rate?

The mass flow meter has high accuracy. But the price is expensive. Therefore, when you need high-precision measurement, you can choose to use a mass flow meter.

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Tool: Volumetric Flow Rate & Pipe Diameter to Flow Speed Calculator

Find the most appropriate industrial grease flow meter from Sino-Inst for a variety of engineering and industrial purposes. Suitable for various fluids with different pressures and volumes. The choice of these depends on whether the volumetric or mass flow rate is to be measured. Grease flow meters offered on the site have wide minimum and maximum pressure ranges, which is considered to be a desirable quality as they can be used for a wider variety of fluids. These grease flow meters are highly accurate.

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What is Flow Meter K-factor? And how to calculate?

What is the K-factor in a flow meter?

K-factor is a coefficient calculated by calibrating and comparing with other measuring devices that meet the accuracy requirements. The Flow Meter K-factor will be confirmed before it is put into use.

This coefficient is a fixed value. It is the actual coefficient obtained by the flowmeter manufacturer after verifying each instrument. Nothing to do with the initial design

The flow coefficient of the flowmeter refers to the proportional relationship between the measured flow and the flow of the standard device under certain conditions. The Flow Meter K-factor is given by the manufacturer when it is calibrated.

The K value is easily immobile. Therefore, as a manufacturer, we generally set a password for the flowmeter.

Flow meter k-factors

Liquid Turbine Flow Meter is a speed-type flow meter based on the principle of torque balance.

The fluid flows through the sensor housing. Because the blades of the impeller have a certain angle with the flow direction. The impulse of the fluid makes the blades have a rotational torque. After the friction torque and fluid resistance are overcome, the blades rotate. The speed is stable after the torque is balanced.

Under certain conditions, the speed is proportional to the flow rate.

Due to the magnetic permeability of the blade, it is in the magnetic field of the signal detector (composed of permanent magnets and coils). The rotating blade cuts the magnetic lines of force. The magnetic flux of the coil is periodically changed. Electrical pulse signals are induced at both ends of the coil.

This signal is amplified and reshaped by an amplifier. A continuous rectangular pulse wave with a certain amplitude is formed. It can be transmitted to the display instrument remotely. The instantaneous flow or total amount of the fluid is displayed.

Within a certain flow range, the pulse frequency f is proportional to the instantaneous flow Q of the fluid flowing through the sensor. The flow equation is:

Where:
f——Pulse frequency [Hz]
k——The meter coefficient of the sensor [1/m3], which is given by the calibration sheet.
Q——The instantaneous flow of fluid (under working condition) [m3/h]
3600-conversion factor in seconds

The meter coefficient of each sensor is filled in the verification certificate by the manufacturer. The k value is set in the matching display instrument. The instantaneous flow and cumulative total can be displayed.

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Vortex flowmeter is a speed-type flowmeter produced according to Karman’s vortex principle,
which can be used for the measurement and measurement of conventional gas, steam and
liquid.

Vortex flow sensor has high precision and wide range ratio, no moving parts in use, which can
improve mechanical stability and reduce maintenance. Vortex flowmeter is almost not affected by the temperature, pressure, and composition of medium when measuring the volume of working conditions.

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Therefore, it is convenient to calibrate the instrument, so the vortex street flow sensor is widely used in production and life.

When a trigonal column vortex generator is set in the fluid, regular vortices are generated alternately on both sides of the vortex generator, which is called Carmen vortex.

The vortex columns are arranged asymmetrically downstream of the vortex generator. Vortex flowmeter is produced according to this principle.

Vortexes are generated by generating bodies and the number of vortexes is detected by high-sensitivity sensors. In a certain range, the number of vortexes generated is proportional to the flow rate.

In vortex flowmeter, the relationship between flow rate and the number of vortexes generated
can be expressed by the following formula:

Q:Operating volume flow of the measured medium. The unit is m3/h。
F:Frequency of the number of vortices produced by the generating body. The unit is Hz.
K:Refers to the calculated or calibrated flow coefficient. It represents how many frequency signals per cube. the coefficient is usually obtained by calibration.

The formula of standard table method calibration coefficient K:

The formula can also be used for flow correction.

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K coefficient of gear flow transmitter (flow coefficient) defines the number of impulses per L within the unit flow precisely.

The following formula is used:

Q=f×60/K

Q=Instantaneous flow L/min
F=Frequency of output impulse(HZ)
K= Coefficient of gear flow meter(impulse/min)

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K-Factors calculation

1.What is a K-factor?

Simply stated a K-factor is a dividing factor. The term is usually encountered when dealing with pulse signals although analog K-factors are sometimes used.

2. Pulse Signal K-factors

All pulse output type flow meters when they are dispatched by their manufacturer will have a calibration certificate. The calibration certificate will show that the meter has been calibrated over its flow range and noted on the certificate will be the average K-factor for the meter.

This K-factor will be given in terms of the number of pulses produced by the meter for a given volumetric flow. (e.g.) 200 pulses per U.S. gallon, 150 pulses per liter, etc.

This K-factor is the value that is entered into a batch meter or indicator/totalizer in order to give a readout in engineering units.

Example 1

If the display on a rate meter is required in U.S. gallons per second, and the K-factor of the flow meter is 210 pulses per U.S. gallon, then the K-factor entered into the rate meter would be 210.

If a totalizer associated with the same flow meter was to be set up so as to totalize in U.S. gallons the totalizer K-factor would be 210.

If the totalizer was to be set to totalize in tenths of a gallon the K-factor would be 210/10 = 21

Example 2

If the display on a rate meter is required in U.S. gallons per minute, and the K-factor of the flowmeter is 210 pulses per U.S. gallon, then the K-factor entered into the rate meter would be: 210/60 = 3.5

3.K-factors for Analog Input Signals

When batching, indication or totalization has to be carried out using an analog input signal a KEP product first converts the 4 to 20 mA signal into a 0 to 10000 Hz. signal. The K-factor is then calculated by relating the engineering unit equivalent of 20 mA to the 10000 Hz. signal.

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Example 3

A vortex meter outputs 20 mA when the flow is 2000 U.S. gallons per minute, we wish to display the rate in gallons per minute.
The rate K-factor is = 10000/2000 = 5

The value of the totalizer K-factor will depend on whether the flow rate was given in units per second, a minute, or hour and whether it is desired to totalize in whole units, tenths, hundredths, etc.

If the flow rate was given in units per second the totalizer K-factor (for whole units) is obtained by multiplying the rate K-factor by 1.

If the flow rate was given in units per minute the totalizer K-factor (for whole units) is obtained by multiplying the rate K-factor by 60.

If the flow rate was given in units per hour the totalizer K-factor (for whole units) is obtained by multiplying the rate K-factor by 3600.

The totalizer K-factor in example 3 will be = 5 x 60 = 300 in order to totalize in gallons.

If we wished to totalize in tenths of a gallon the K-factor would be 5 x 60/10 = 30

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Example 4

An electromagnetic flow meter outputs 20 mA when the flow is 20 liters per second, we wish to display the flow rate in liters per second and totalize in M³.
The rate K-factor is 10000/20 = 500
The totalizer K-factor will be 500 x 1/0.001 = 500000

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4.Multi-Point K-factors

Some flow applications dictate that multiple K-factors are used. Two applications that require multiple K-factors are:

  • flow meters with nonlinear outputs
  • wide turndown flow applications

KEP meters have an option available that allows the user to input from 3 to 16 K-factors. This multi-point K-factor option is available for both pulse and analog inputs.

5.Multi-Point K-factors for Pulse inputs

The first step is to calculate K-factors to cover each flow range. This is done by taking the information on the flow meter manufacturer’s calibration sheet and calculating the K-factors as per section 2. An alternative to using the manufacturers’ data is to conduct tests on-site against a calibrated standard.

The second step is to relate an incoming frequency range from the flow meter to a given calculated K-factor.

The final step is to program these values into the KEP instrument.

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Example 5

A turbine flow meter has the following calibration data.

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6.Multi Point K-factors for Analog Inputs

The procedure for analog inputs is essentially the same as for pulse inputs.

The first step is to calculate K-factors to cover each flow range. This is done by taking the information on the flow meter manufacturer’s calibration sheet and calculating the K-factors as per section 3. An alternative to using the manufacturer’s data is to conduct tests on site against a calibrated standard.

The second step is to relate an incoming flow value from the flow meter to a given calculated K-factor.

The final step is to program these values into the KEP instrument.

Example 6

A vortex flowmeter has the following calibration data.

Base K-factor 10000/100 = 100

Note that the point after the final one should have a flow value entered that is very much higher than the true maximum flow rate of the meter. Note also that as the last two K-factors are the same any flow above 100 gpm will be modified by a K-factor of 104. The setup is now complete.

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Sino-Inst offers over 50 flow meter for flow measurement. About 50% of these are differential pressure flow meters, 40% is the liquid flow sensor, and 20% are Ultrasonic flow Transmitter and mass flow meter.

A wide variety of flow meters options are available to you, such as free samples, paid samples.

Sino-Instrument is a globally recognized supplier and manufacturer of flow measurement instrumentation, located in China.