Inline water flow meters

Inline water flow meters-ultrasonic

Inline water flow meters are instruments that can be installed directly on water flow pipes to display flow. In principle, there are mechanical, ultrasonic, electromagnetic, and so on. Used in residential water pipes or industrial water pipes.

An inline flow meter is a flow meter with the function of displaying flow rate on-site. The sensor of the flow meter is installed on the fluid pipe. Digital display or pointer shows the flow rate on the spot.

In-line flowmeters could be digital and mechanical flow meters. Common in-line flowmeters include turbine flowmeters, electromagnetic flowmeters, and ultrasonic flowmeters. With stainless steel material, analog, and 4-20mA output, in-line flow meters can measure and control inline flow.

Read more: Choose the most suitable Inline flow meter

Featured inline water flow meters

Strap on flow meter X3

 External clamp-on flow sensor. Easy to install. Suitable for measuring pipe diameter Φ9.53~Φ90.

Ultrasonic Water Meter for Residential Water

DN15-DN40, RS485. LORA/ NB-IoT, WIFI, Output MBUS, MODBUS, ASCII, CJ188 are optional.

Sandwich-type Insertion Ultrasonic Water Flow Meter

DN50-DN150. New type. The thickness is only 50mm.

Dual Channel Ultrasonic Water Meter

Can be battery-powered and wireless. For residential water, urban water, industrial water management.

In-Line Ultrasonic Flow Meter

DN15-DN6000, InLine Ultrasonic Flow Meter Reference price: USD 470.00/pc

Insertion Magnetic Flow Meter

 Suitable for large diameter DN300-3000. Insertion magnetic flowmeter can be installed without stopping the flow.

Liquid Turbine Flow Meter

DN4~DN200. Liquid Turbine Flow Meter reference price: DN100. USD 600-700/pc.

Turbine Sanitary flow meter

DN4-50mm. Sanitary Turbine Flow Meter reference price: DN100. USD 300-700/pc.

Magnetic Water Flow Meter

DN15~DN3000, Conductive liquids such as drinking water, sewage, wastewater, seawater, ammonia, cement slurry, etc.

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Residential inline water flow meter

The residential inline water flow meter is an essential thing in modern residents’ homes. The residential inline water flow meter is used to measure household water consumption. It is also the basis for the water company’s charges.

Domestic inline water meters are provided and installed by the water supply company.

The price of the water meter is determined according to the function of the water meter. At present, the water meters on the market are divided into mechanical water meters, IC card water meters, remote water meters, photoelectric direct reading water meters, NB-IoT Internet of things water meters, etc. The prices are different for different levels.

Generally speaking, the price of mechanical water meters is relatively cheap. The price of smart water meters is more expensive. At present, the relatively new type is the NB-IoT remote transmission water meter, which is convenient for meter reading, mobile phone operation, no wiring, and wireless transmission of signals.

Read more about: How does a residential water meter work?

  1. Divided according to the functions used, the smart IC card water meter is more commonly used now. That is to say, this smart water meter has an IC card inserted into the water meter. You can query the water consumption at home and the water bill.
    • And one of its biggest features is that it can pay water charges in advance. It can also solve the trouble of water company charges. Before, it was necessary for staff to go door-to-door to read the meter. With this smart IC card, it can be inquired remotely.
  2. Now a remote water meter has been developed. According to its literal meaning, it can also be understood that this kind of water meter is also very intelligent. There is no need to go to the house to read the meter. The staff can understand the water consumption of each customer in the office. It also brings a great deal to the water supply company. Convenience. Solved the problem of a nuisance to the people.
  3. Intelligent valve-controlled water meter. One of the bright spots of this type of water meter is that you need to pay money before you can use it. It is very useful for users who are in arrears of water bills. It is also tailored for these users. And it can be controlled remotely and is very intelligent.
  4. According to the nature of the water meter, it can be divided into rotor wet water meter or dry water meter, or speed water meter, volume water meter, and so on.

Extended reading: Flow Totalizer F3000X for Data collection and calculation

Extended reading:
What is the K-factor in a flow meter?
Cryogenic Flow Meters|Liquid Nitrogen-Liquid Oxygen-LNG fluids

Industrial inline water flow meter

Industrial inline water flow meters are more complicated than residential water meters. Because residential water is mainly used to measure tap water. Industrially, it is necessary to measure water, including raw water, wastewater, condensed water, and various aqueous solutions.

Extended reading: 2 inch Water Flow Meter

You can refer to the following to select the appropriate Industrial inline water flow meter.

Industrial Magmeters

What is a Magmeter? Magmeter is a volumetric flow meter that measures the flow of…

Hot Water Flow Meters

Hot Water Flow Meters Improve Heating-Boiler System Hot water flow meters refer to flow meters…

Mechanical water flow meter

A mechanical water flow meter relies on the kinetic energy of the water flow to drive the metering mechanism to work. The water flowing through the water pipe impacts the water meter impeller and then drives the gear to rotate, without electricity.

The mechanical water flow meter is currently used less, mainly due to the following reasons:

There are many vulnerable parts, and the existence of the movable part impeller is easy to cause fouling of itself and the measuring cavity. Even blockage, especially when the water quality is poor. Therefore, the reliability and stability of the work are relatively low;

The movable part of the impeller shaft core is easy to wear after a long time or high flow rate operation. Especially when the water quality is corrosive. Therefore, the durability of work is low, and the service life is relatively short;

The presence of the impeller in the measurement chamber will produce a large pressure loss. Reduce the transmission capacity of the heating pipe network. In particular, it brings difficulties to the transformation of the old pipe network;

The accuracy of flow measurement is relatively low. There are also certain requirements for the flow rate of the fluid. Can not effectively measure when the flow rate is low.

Read more about Sanitary Flow Meters-316SS, Tri clamp-Pulse- for Brewery

Digital flow meter

Compared with a Mechanical inline water flow meter, a Digital flow meter makes it easier for users to obtain flow information.

Digital flow meter generally has a digital display. The traffic can be displayed locally. Including instantaneous flow and cumulative flow. It can even display information such as pressure and temperature.

Digital flow meter generally also supports remote data transmission. Digital flow meter outputs pulse, 4-20mA, and other signals. Support HART, RS485, and other protocols. Even wireless remote transmission.

Read more about Digital Flow Meters


The flowmeter is produced according to the user’s measurement parameters. Therefore, the price of the flowmeter is different for different measurements.

Important factors when selecting flow metering devices are

  • accuracy
  • cost
  • legal constraints
  • flow rate range
  • head loss
  • operating requirements
  • maintenance
  • lifetime

These factors are more or less related to each other. For example – the cost of flow meters increases with accuracy and lifetime quality.

Extended reading: Featured Cheap flow meters for Sale

The general measurement is to use an electromagnetic flowmeter.

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.

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.

Read more about Digital Water Flow Meters

Flowmeter usually refers to industrial flow meters. Water meter usually refers to the residential water meter.

Industrial VS residential digital water flow meter

1. From a functional point of view. Industrial digital water flow meter mainly measures instantaneous flow. It is a real-time state. It can understand the usage of each site. And can output pulses, 4~20mA, etc. The residential digital water flow meter is mainly a cumulative function, generally cannot see the instantaneous flow.

Extended reading: Ultrasonic water meter working principle

2. From the cost point of view. The manufacturing cost of the Residential Digital Water Flow Meter is relatively low. The cost of an Industrial Digital Water Flow Meter is generally relatively high.

3. In terms of quality. Relatively speaking, the Residential digital water flow meter has poor accuracy. It cannot withstand high pressure and high temperature, and cannot output linear signals. It cannot participate in the automation control of modern industry. The industrial digital water flow meter can do the above.

4. From the point of view of usage. Residential digital water flow meter only measures water and is not used to measure gas. And some liquid media water meters cannot be used. Industrial digital water flow meter liquids (water, oil, turbid liquids, etc.) can be measured.

Of course, Residential digital water flow meters can realize various functions such as prepayment. Remote data transmission. Remote valve control. Step water pricing, etc. It is a must-use metering product for residential homes.

Extended Reading: Inline Ultrasonic Flow Meter

Extended reading: Industrial Magmeters

Sino-Inst offers over 30 Inline water flow meters products. About 50% of these are magnetic flow meters. 40% are water meters (like the ultrasonic flow meter), and 40% are water treatment (like the Annubar flow meter ).

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

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

The top supplying country is China (Mainland), which supply 100% of the Inline water flow meters respectively.

Sino-Inst sells through a mature distribution network that reaches all 50 states and 30 countries worldwide. Inline water flow meters products are most popular in Domestic Market, Southeast Asia, and Mid East.

You can ensure product safety by selecting from certified suppliers, with ISO9001, ISO14001 certification.

Furnace thermocouple Topics

How does a furnace thermocouple work?

In industrial furnaces, armored thermocouples are often used as Furnace thermocouples. The thermocouple body has a metal sheath, which can directly measure the temperature of the medium. Or it can be placed in a protective tube as a temperature measurement core element. It has the advantages of bending, high-pressure resistance, fast thermal response time, sturdiness, and durability.

Armored thermocouples are usually used in conjunction with display instruments, paperless recorders and regulators. It can measure the temperature of liquid, vapor and gaseous media and solid surfaces in the range of 0-1600°C during various production processes.

Place the thermocouple core wire and inorganic mineral insulating material in a metal sleeve. The stretched solid assembly that can be wound becomes an MI Cable.

The armored thermocouple cable made of thermocouple wire as the core is welded to form the measuring end and assembled with the relevant junction box. The thermocouple is called the armored thermocouple. Furnace thermocouples can be manufactured into insulated, grounded, and exposed-end types as required.

Furnace thermocouple-Solution for coal chemical gasifier

The gasifier is the most representative device of the coal chemical industry. Sino-Inst is based on the special conditions of the TEXACO gasifier and the Shell gasifier. It shares the special structure and material selection of the gasifier thermocouple and other professional knowledge. Help users solve special problems The problem of temperature measurement in the occasion.

Accurate measurement and strict control of temperature are the key factors to ensure the normal operation of the process. It will directly affect whether the process is carried out under ideal conditions. It will even affect the service life, safety production and environmental protection of the overall equipment.

The temperature measurement conditions of TEXACO gasifiers and Shell gasifiers in the coal chemical industry are extremely specific due to the gasifier body structure, internal medium, reaction process, and operating conditions. Therefore, the choice of the corresponding Furnace thermocouple also highlights its special importance and complexity.

The author relies on many years of rich experience. The representative and typical working conditions of TEXACO gasifier and Shell gasifier. As well as the selection principles and precautions of the corresponding thermocouples, which I will discuss with you. It aims to provide reference guidance and suggestions for coal chemical users.

1.TEXACO gasifier

① Operating conditions of TEXACO gasifier

Representative sites of TEXACO gasifiers include Ningxia Coal Group’s 250kt/a methanol plant, Shenhua Baotou and Inner Mongolia Jiutai Energy’s coal-to-olefin project.

The above site adopts the TEXACO rapid cooling process and the whole waste boiler process, which is the most advanced energy-saving process in the world.

TEXACO gasifier has special working conditions such as high temperature, high pressure, coexistence of oxidizing and reducing atmospheres, strong scouring, and sudden changes in temperature and pressure.

The operating temperature of the combustion chamber is 1350-1500℃, and the operating pressure is 2.5-8.7 MPa.

The flame gas contains CO, H2, CO2, H2O, CH4, Ar, N2 and H2S and other components.

The melting point of coal ash is 1310-1370°C.

The shell of the combustion chamber and the lining refractory bricks are likely to shear each other due to the different coefficients of thermal expansion.

The most important thing is that the scouring and abrasion in the gasifier is extremely serious, so the measuring point of the thermometer must be located 15-25mm away from the inner wall of the furnace wall.

However, it is difficult to ensure uniformity in the furnace wall during the masonry process. Coupled with the existence of scouring and wear in the furnace. The furnace wall will be inevitably thinned gradually during the production process.

②The performance requirements of TEXACO gasifier for Furnace thermocouple:

Due to the special working conditions of the above-mentioned TEXACO furnace, the temperature sensor must be able to withstand a high temperature of 1600°C and a high pressure of 8.7MPa.

It can resist the double corrosion of oxidizing and reducing gas at the same time.

It has an adjustable insertion length and a follow-up structure. When the inner lining changes in thickness and torsion and shear, corresponding structural changes can be made.

③Temperature measurement solution for TEXACO gasifier

In response to these requirements, the Furnace thermocouple is designed with special materials and structure. It satisfies the harsh requirements of the gasifier operating conditions for the temperature sensor. It is a kind of thermocouple special for gasifiers with adjustable anti-vibration, erosion resistance, anti-oxidation, and multi-stage leakage resistance.

First of all, the main structure of the Furnace thermocouple adopts the design concept of adjustable anti-vibration.

When the thickness of the gasifier wall lining changes, the Furnace thermocouple can be adjusted within the range of ±120mm through the shrinkable threaded sleeve. In order to achieve the measurement, the element is always maintained in the best position.

When the furnace shell and the inner lining are sheared, the universal rotating ball can be used to make the probe rotate with the inclination. And under the action of the limit guide tube and the correction damping spring.

Keep the probe always in the correct position in the center of the wall bushing. It prevents the thermocouple of the gasification furnace from being broken when the furnace wall is deformed.

Multi-stage leak-proof structure design. When the thermowell is damaged, it can prevent convection between the inside of the furnace and the outside through the sleeve. Safety hazards caused by high temperature conduction or even leakage in the furnace. Reflect safety awareness and environmental protection concepts.

Secondly, the Furnace thermocouple protection tube material adopts imported silicon carbide material made by pressureless sintering of sub-micron silicon carbide powder. The material has the dual characteristics of ceramic and metal and can be used reliably even at high temperatures exceeding 1750°C.

Its thermal conductivity is equivalent to stainless steel, 5 times that of alumina. Hardness is one of the high-performance materials second only to diamond. Ultra-fine crystals smaller than 10μm have been tested by helium gas leak detection.

The porosity is almost 0, which can effectively prevent H2 and CO from damaging the Furnace thermocouple wire through the pores on the tube wall. Ultra-high hardness and density make it have ideal wear resistance and long-term resistance to material erosion. It can work in oxidizing and reducing atmospheres and corrosive environments of strong acids and alkalis even at ultra-high temperatures.

2.Shell gasifier

At present, more than ten sets of Shell gasifiers have been introduced in China. Representative sites are Henan Kaixiang Methanol Project, Yunwei Group’s synthetic ammonia and Guangxi Liuhua coal gasification plants.

①Shell gasifier operating conditions characteristics

Conditions to ensure the normal operation of Shell gasifiers:

Neither can cause damage to the over-temperature of the vaporizer. It is necessary to consume the lowest amount of oxygen as much as possible. To achieve complete carbon conversion, temperature control is essential.

However, the structural characteristics of the Shell gasifier determines that the temperature of the gasifier cannot be directly measured. It can only be controlled by indirect methods.

An “annular space” is formed between the inner membrane wall of the gasification furnace and the outer shell. Hot syngas cannot escape into the “annular space”, causing the shell to overheat. Calculating the temperature in the furnace by measuring the temperature of the water wall in the “annular space” is the characteristic of Shell gasification furnace temperature measurement.

The temperature in the “annular space” is collected at multiple points, and each temperature measurement point is the key to understanding whether the gasifier is operating normally. If there is any abnormality, find and analyze the cause immediately. And deal with it in time, otherwise it will cause major damage to the gasifier.

②Shell gasifier performance requirements for Furnace thermocouples

Because the pulverized coal of Shell gasifier is 4MPa. It is combusted with O2 and steam in a gasifier at around 1500°C. And when it was sent to the coal burner, it was already under a pressure of 2MPa. Therefore, the thermometer is required to have a pressure resistance of not less than 2MPa. It also has emergency measures in case of overpressure, and can withstand a high temperature of 1500°C.

Because the Shell gasifier is composite equipment that integrates dynamic and static equipment, as well as combustion, reaction, heat exchange, and quenching processes. Therefore, it is required that the thermocouple used must be easy to install and remove, and easy to replace. Because of its complex structure and many control points, a multi-point thermocouple must be used.

③Shell gasifier temperature measurement solution

The design solution of the special Furnace thermocouple for the multi-point core-pulling and leak-proof Shell gasifier has solved the on-site requirements.

a. Multi-point thermocouples of different lengths (up to 6m) are used to measure the temperature of different control points in one fell swoop, using 3-point or 4-point thermocouples.

b. According to the characteristics of on-site installation, 4in (1in=25.4mm) No. 600 flange mounting parts are used. This part and the temperature measurement body are separable structures. The flange installation and fixing can be completed first. Then the temperature measurement body Installation with flange.

This solution allows the bulky flange to be installed at one time. In daily maintenance, only the main part needs to be replaced, which is convenient and quick. Closely combined with this structure is the independent replaceability of the core elements. Each measuring element is a detachable individual. If any one fails, it can be taken out and replaced separately. The maintenance cost and the quantity and expense of spare parts are reduced.

c. Due to the large amount of HCl in the medium in the furnace. Incoloy and Inconel alloys are often used in equipment manufacturing. In order to maintain a high resistance to high temperature and corrosion, the selection of Furnace thermocouple protection tube materials must all use Inconel600 alloy. Keep temperature measurement components , The material consistency of the mounting flange and the sealing sleeve.

d. The thermometer must have a multi-stage leak-proof sealing structure design. That is, each element must have a double-stage leak-proof device. When any temperature measuring element is damaged, due to the existence of leak-proof, the “annular space” The high temperature and high pressure airflow will not leak. It also guarantees the safety and environmental protection on-site requirements.

3.Furnace thermocouple installation instructions

①After the gasifier is shut down, consider the decompression effect of refractory materials and pressure vessels and the problems of thermal expansion and contraction. The pressure relief and replacement process of the gasifier is carried out slowly, and the furnace pressure should be basically reduced to atmospheric pressure and completely replaced.

After that, while the molten slag has not completely solidified, the gasifier thermocouple is drawn out of the furnace.

If the slag is solidified, the thermocouple ceramic sleeve cannot be pulled out, only the metal part at the back can be pulled out. The ceramic sleeve is usually driven into the furnace with a special tool.

②When installing a new gasifier thermocouple, put the assembled gasifier thermocouple on a special bracket. The bracket is placed on the wheeled trolley so that the gasifier thermocouple is exactly aligned with the gasifier thermocouple.

The equipment takes over in the middle. Slowly push the gasifier thermocouple into the furnace, about 10mm every 5 minutes. Protect the thermocouple from thermal shock.

Related Products:

Sino-Inst, Manufacuturer for Temperature Transmitters, like: Armoured thermocouple, assembly thermocouple, explosion-proof thermocouple, etc.

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

Guidebook: Bimetallic Stemmed Thermometer

A bimetallic stemmed thermometer is a simple but effective tool used in a variety of industries, including food, HVAC, medical, and automotive. It’s easy to use, requires no external power source, and is highly durable. In this guidebook, we’ll explain how a bimetallic stemmed thermometer works, its advantages and disadvantages, how to use it, and its various applications. So, whether you’re a professional or just curious about thermometers, you’ll find everything you need to know right here. Let’s get started!

What is a bimetallic stemmed thermometer?

Bimetallic stemmed thermometer is an instrument that uses two different metals to measure temperature. Combine two metals with different coefficients of linear expansion and fix one end. When the temperature changes, the two metals thermally expand differently. Drive the pointer to deflect to indicate the temperature. This is the bimetallic thermometer. It can directly measure the temperature of liquid, steam, and gaseous media in the range of -80℃~+500℃ in various production processes.

Benefits of Bimetallic stemmed thermometer

(1) The thermoelectric potential is not disturbed. The thermoelectric potential of the bimetal thermometer is not disturbed by other factors. It has strong adaptability to different measurement environments. 

(2) The structure is diverse and can meet different measurement requirements. It can be used as electric contact bimetal thermometer, explosion-proof electric contact bimetal thermometer, bimetal thermometer with remote transmission, etc.

(3) The temperature response speed is fast, and there is strong sensitivity. At the same time, temperature changes are intuitive and can be displayed and recorded on site.

(4) Small size, convenient application, and strong temperature measurement reliability. Nominal diameter of dial: 60,100 (4 inch), 150 optional;

(5) It has a long service life, can be used in the temperature detection of chemical production for a long time, and has stable physical and chemical properties.

(6) Stable anti-corrosion performance. The application of bimetallic thermometers in chemical production often needs to be used in liquid and gas environments. It has a good anti-corrosion ability to protect pipes. It will not be affected by measurement conditions and cause corrosion problems that affect measurement quality.

(7) Strong pressure bearing. It has good pressure-bearing capacity, can be measured in different pressure levels, and has strong adaptability to measurement conditions.

(8) The conductivity is high. The temperature coefficient of resistance is small, and the thermoelectric potential has a linear relationship with the temperature, and the linearity is good.

A bimetallic stemmed thermometer works by using two different metals that are joined together. When the temperature changes, the two metals expand at different rates, causing them to bend or twist. This movement is then translated into a temperature reading on the dial. It’s like when you’re trying to open a jar that’s been in the fridge – you run it under hot water to expand the lid and make it easier to open. The bimetallic thermometer works in the same way, using the different expansion rates of the two metals to measure temperature accurately. It’s a simple but effective method that has been used for many years.

Here are some benefits of using a bimetallic stemmed thermometer that you might find helpful:

Highly Accurate: A bimetallic stemmed thermometer is one of the most accurate ways to measure temperature.
Durable: These thermometers are made to last.
No External Power Source Required: You don’t need to plug a bimetallic stemmed thermometer into an electrical outlet or replace batteries.
Versatile: You can use a bimetallic stemmed thermometer in many different situations.

In summary, a bimetallic stemmed thermometer is a simple, reliable, and accurate tool that is versatile and durable. It’s a great option for anyone who needs to measure temperature regularly.

How to Calibrate a Bimetallic Thermometer

Method 1: Ice water

1. Fill the container with ice cubes, and then top up with cold distilled water to form a watery slurry.

2. Insert the thermometer probe into the container, making sure not to touch the side.

3. The temperature should be 32°F (0°C) after 30 seconds. If not, the thermometer needs to be recalibrated. Record the difference and offset the thermometer as needed.

Method 2: boiling water

1. Boil a clean container of distilled water.

2. Once the water boils, insert the thermometer probe. Make sure again that the probe does not touch the side or bottom of the pot.

3. The temperature should be 212°F (100°C). Record the difference and offset the thermometer as needed. Note that the boiling point of water varies with altitude. Use this handy water boiling point calculator to find the temperature that suits your altitude.

The bimetal thermometer is an on-site detection instrument for measuring low and medium temperatures. It can directly measure the temperature of liquid, steam and gas medium in the range of -80℃~500℃ in various production processes.

The electric contact bimetal thermometer is used in the production site for temperature control and alarm.

Directly measure the temperature of liquid, steam and gaseous media in the range of -80℃~500℃ in various production processes.

The explosion-proof bimetal thermometer can directly measure the presence of hydrocarbons and other explosives at the scene. Directly measure the temperature of liquid, steam and gaseous media in the range of -80℃~500℃ in various production processes.

The remote bimetal thermometer can directly read the field temperature. And can transmit the temperature signal to the remote control system.

Extended reading:  Tri Clamp Sanitary Thermometers

Temperature range Accuracy class Graduation value ℃ Minimum insertion depth Lmin (mm)
Φ6 Φ8 Φ10
-40℃~80℃ 1.5 2 45 55 60
0℃~50℃ 1.5 1 110 130 140
0℃~100℃ 1.5 2 55 65 70
0℃~150℃ 1.5 2 40 45 50
0℃~200℃ 1.5 5 30 35 40
0℃~300℃ 1.5 5 50 60 60
0℃~400℃ 1.5 10 40 50 50
0℃~500℃ 1.5 10 35 40 40
0℃~600℃ 1.5 10 30 35 35
customizable 1 * * * *

Related Products:

Sino-Inst, Manufacturer for Bimetallic stemmed thermometers, like Digital Thermometer/Transmitter, Digital Thermometer/Transmitter, explosion-proof thermocouple, etc.

Sino-Inst’s Bimetallic stemmed thermometers, made in China, Having good Quality, With better price. Our Temperature measurement instruments are widely used in China, India, Pakistan, the US, and other countries.

Oil-water Interface Level Measurement Guide

Interface level measurement is very important for oil and gas, chemical tanks. At the same time, Interface level measurement is also a measurement and control challenge.

In today’s increasingly modernized oilfield production, automated crude oil processing has become a guarantee for the quality of refined oil. The performance of the oil-water interface fundamentally affects several key issues in crude oil processing: the water content of crude oil, energy consumption, sewage discharge indicators, etc.

Here we mainly compare the working principle, usage and common failures of several oil-water interface instruments commonly used in North China Oilfield. Hope to help you find a suitable solution when measuring oil-water interface.

Interface level measurement technologies

According to the different measurement principles of the interface instrument, the interface instrument can be roughly divided into: magnetic radio frequency admittance type, short wave absorption type, capacitive type, servo type and so on.

Among them, the magnetic interface instrument is divided into: reed tube type magnetron interface instrument, magnetostrictive interface instrument and other forms.

Interface level measurement using Magnetostrictive interface instrument

A rigid tube or flexible tube leads from the top to the bottom of the tank, and the float with magnetic steel moves up and down along the wave guide with the liquid surface.

During the measurement, the current pulse excites a stress pulse on the waveguide in the tube where the magnetic float is located. Propagate along the waveguide to the measuring part in the top electronic box at the speed of sound. Is converted into electrical pulses.

The position of the liquid level can be determined based on the propagation time of the stress pulse.

If there is a second float, choose the relative density appropriately. Make it float on the oil-water interface. Then the position of the oil-water interface can be measured at the same time.

Interface level measurement using Reed switch level sensor

The reed tube type magnetic control interface instrument is also called the magnetic float ball level gauge.

This type of interface instrument was used earlier in the oil field, and now there are more problems.

The measurement principle is extremely simple. Attach a circuit board consisting of a reed switch and resistors. The length is determined by the height of the measured medium.

Put it into a stainless steel tube, as the magnetic float sleeved outside the steel tube moves with the liquid surface, the magnetic force will attract the corresponding dry reed tube. The resistance value of the output terminal of the circuit board also changes accordingly.

According to the density of the measured crude oil. Appropriately match magnetic floats with different relative densities. The liquid level and interface can be measured.

Know more about: Continuous Float Level Sensor & Switches

Interface level measurement using Shortwave

The meter is based on the theory of medium absorption of short waves. Electric energy is radiated into the oil-water medium in the form of an emulsion in the form of electromagnetic waves. The content of the two media is detected based on the difference in the electric energy absorbed by the oil and water.

The dielectric constant of oil is about 2.3, while that of water is about 80. There is a great difference between the two.

The oil-water interface is detected by measuring the oil-water content.

Extended reading: Radar Oil Tank Level Sensor

Interface level measurement using Capacitive

Capacitive interface meter uses the difference in electrical conductivity between oil and water media to make the capacitance and the height of the water have a linear relationship. To achieve the purpose of monitoring the oil-water interface.

Nowadays, radio frequency admittance type is used to replace the traditional capacitive interface instrument.

Capacitive Level Sensors can be used for point level detection and continuous level measurement, particularly in liquids. The measuring principle is based on the change of the capacitance in a capacitor. The electrically conductive tank wall and a probe inside of the tank form a capacitor, The capacity changes of which are used to determine the level. This animation shows the measuring principle in conductive liquids and non-conductive liquids. The Capacitive Level Sensor can convert the changes of various levels and the height of the liquid level into standard current signals. Level Sensors can also support wireless transmission, RS485 digital communication transmission, etc.

Interface level measurement using Servo Level Meter

Servo Level Meter is a high-precision measuring instrument that measures the level of liquid level with microelectronic technology and servo motor drive technology.

Servo Level Meter can carry out routine and accurate measurement and signal transmission of liquid level, interface level and density of the measured medium. It also has functions such as temperature transmission. It can meet the requirements of storage tank inventory management, loss control cost saving and safe operation.

Servo Level Meter is explosion-proof design and has strong expandability. It can be widely used in a variety of flammable and explosive places. It is an ideal choice for liquid level measurement in storage tanks in the fields of petroleum and petrochemical, electric power, medicine, and food.

Single Servo Level Meter: It can realize real-time oil tank level, boundary level measurement display and remote transmission display.

Servo Level Meter is equipped with a multi-point thermometer: it can realize the temperature measurement of the oil tank’s liquid level, boundary level, and different point heights on site.

Servo Level Meter is equipped with a multi-point thermometer and a tank side display: it can measure and display the liquid level, boundary level and temperature of the oil tank at different heights on site.

Explore Oil and Gas Flow Meters

Interface level measurement using DP transmitter

Differential pressure (DP) transmitters are used to measure the interface of two fluids with different specific gravities. This measurement can be made with or without a distal seal. It is important that the height must be large enough to create a reasonable DP between the two specific gravity limits.

Suppose the measuring H distance is 1.2m, the density of oil is 0.7, and the density of water is 1.0. The pressure guiding pipe on the high and low pressure side is filled with water as a sealing liquid. Find the range of the differential pressure transmitter.


Differential pressure at the lowest water level: P=(ρoil×g×H)-(ρwater×g×H)


Differential pressure at the highest water level: P=(ρwater×g×H)-(ρwater×g×H)


The range of the transmitter is: -3.528Kpa to 0 Kpa

Quick calculation of range: (ρ water-ρ oil)×g×H=3.528Kpa

Note: This algorithm is only used for working conditions with obvious oil and water layers. It is undesirable if oil and water are miscible to form an emulsified quality.

Read more about: 7 Level Senors for Tank Level Measurement

In oil field production, oil-water separation is an extremely important link in crude oil processing. After the crude oil enters the joint station, it has to go through treatment processes such as sedimentation and power-off. Oil-water interface control is the key to the separation effect.

Nowadays, oilfields generally use special oil-water interface meters to monitor the process. To achieve the purpose of automatic control.

At present, there are many types of oil-water interface instruments. The performance difference is relatively large. Based on the actual situation of the North China Oilfield, the use of the interface instrument is specifically analyzed.

First, give a general introduction to the basic process flow of oilfield production. After the crude oil is extracted, it is sent to the oil production metering station for measurement, and then enters the joint station.

At the joint station, after metering and heating, the crude oil is sent to the primary settling tank. The crude oil in the primary sedimentation tank is kept at about 60°C all year round.

After sedimentation and separation, it is sent to the intermediate tank. After dehydration pump dehydration. After secondary heating, it enters the secondary settling tank.

The crude oil in the secondary settling tank is kept at about 80℃ all year round. The separated crude oil enters the electric dehydrator for final treatment. After reaching the moisture content standard (0.5%). Finally, it is sent to the refined oil storage tank.

In the whole process, it is necessary to measure the oil-water interface. The accurate monitoring of the oil-water interface is critical to the recovery of water content of oil products and the cost of treatment.

Extended reading: Magnetostrictive Hydraulic Cylinder Position Sensor


Capacitive level sensor is based on the change of capacitance to perform liquid/level measurement. The level gauge electrode and the container form two electrodes of a capacitor. The capacitance value varies with the container.
The level of the material medium changes and changes, and is converted to the corresponding level output signal.
A basic requirement for measuring liquid/level with a capacitance level meter is: the relative medium of the measured medium.
The electrical constant (the ratio of the dielectric constant of the measured medium to the air) should not change during the measurement.
Extended reading: Amazing Solutions for Continuous Liquid Level Measurement

There are 7 main types of level transmitters that Sino-Instrument offers. Each type of transmitter works in a different way, and makes it useful for different types of processes.

Capacitance Level Transmitters
Hydrostatic Level Transmitters
Magnetic Level Transmitters
Radar Fill Level Transmitters
Ultrasonic Level Transmitter
Guided Microwave Level Transmitters
Liquid Level Transmitters
Extended reading: Oil Level Measurement Solutions for the Oil & Gas Industry

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Extended reading: Water Tank Level Controller

Sino-Inst offers over 10 Solutions for Oil-water Interface Level Measurement. About 50% of these are interface liquid level meters, 40% is the level switches.

A wide variety of Solutions for Oil-water Interface Level Measurement options are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of Solutions for Liquid Level Measurement instrumentation, located in China.

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