Category Archives: Pressure

Pressure Transducers and Transmitters Manfacturer, China

A pressure transducer also called a pressure transmitter,

is a transducer that converts pressure into an analog electrical signal.

Pressure transmitters are used to measure the pressure,

or level of industrial liquids and gases.

The output is transmitted to a control system.

Accurate and stable process measurements ensure the safe,

reliable, and profitable operation of your plant.

Sino-Instrument is pressure transmitters manufacturer in China.

We offer all types of pressure transmitters.

Like Direct Mounted, flange-mounted, single flange,

double flange, Remote Diaphragm Seals, High Static, Digital Remote.

Most of our pressure transmitters are used in oil, liquids,

DP transmitter, flow measurement, level measurement, density,

and other process variables.

Pressure transducers are generally available with three types of electrical output;

millivolt, amplified voltage, and 4-20mA.

4-20 mA Output Pressure Transducers

These types of transducers are also known as pressure transmitters,

work with HART communicators.

Since a 4-20mA signal is least affected by electrical noise,

and resistance in the signal wires,

these transducers are best used when the signal must be transmitted long distances.

It is not uncommon to use these transducers in applications where the lead wire must be 1000 feet or more.

Choose the right pressure transducer for your application:

SMT3151 TGP Gauge Pressure Transmitter

Posted on March 2, 2026 by KimGuo11

What is a gauge pressure transmitter? A gauge pressure transmitter is a pressure-measuring instrument specifically designed to measure pressure values relative to atmospheric pressure. The gauge pressure sensor’s back cavity is directly connected to the atmosphere. Its biggest advantage is that it is unaffected by changes in external atmospheric pressure when measuring gauge pressure, but its environmental resistance is relatively weak.

The SMT3151 TGP Gauge Pressure Transmitter offers stable performance, can be configured for manifold installation, supports local digital display, and provides signal outputs such as 4-20mA, RS485, and HART. It is the preferred gauge pressure transmitter for industrial pressure monitoring!

Sino-Inst offers a variety of Gauge pressure transmitters for industrial pressure measurement. If you have any questions, please contact our sales engineers.

More Pressure Transmitters

Benefits of Gauge Pressure Transmitter

High accuracy: The pressure transmitter can perform high-accuracy measurements within the measurement range of 0~60MPa.
Excellent overpressure performance: Can withstand 2 times the pressure range.
Intelligent static pressure compensation and temperature compensation protect the transmitter from the influence of temperature, static pressure and overpressure, reducing errors.
LCD digital display with backlight
Built-in three-button quick operation and local adjustment function
Various anti-corrosion materials are available
Multi-faceted self-diagnosis function
Optional signals 0-10V, 4-20mA, RS485, HART protocol, etc.

Read more about: Common Units Of Pressure

Specifications of Gauge Pressure Transmitter

Use object:	Liquid, gas or steam
Measuring range	0-3.5～35kPa 0-10～100kPa 0-35～350kPa 0-0.1～1.0MPa 0-0.35～3.5MPa 0-1.0～10MPa 0-2.1～21MPa 0- 4.1～41Mpa 0- 6.0～60MPa
Output signal:	4-20mAdc. Output, superimposed HART protocol digital signal (two-wire system)
Power source:	External power supply 24V dc. Power supply range 12V ~ 45V
Installation in dangerous places	Flameproof ExdIIBT5Gb; (explosion-proof certificate no. :CE16.1163) Intrinsically safe ExiaIICT4/T5/T6Ga; （explosion-proof certificate no. : CE15.2354X）
Accuracy:	±0.1%, ±0.075%
Stability:	±0.2%/12 months of the maximum range
Temperature effect：	Including zero and range for maximum temperature error of ±0.2% / 20 ℃
Power supply impact:	Less than 0.005% / V of the output range.
Vibration effect:	In any axial direction, the frequency is 200Hz, and the error is ±0.05% / g of the maximum range.
Electronic circuit board work in:	– 40 ~ 85 ℃;
Sensitive components work in :	– 40 ~ 85 ℃;
Storage temperature :	– 40 ~ 85 ℃;
With digital display:	– 25 ~ 75 ℃ (run); – 40 ~ 85 ℃ (no damage);
Relative humidity:	0 ~ 95%
Overpressure limit:	2~5 times the maximum range
Volume change:	Less than 0.16 cm3
Damping:	The time constant is adjustable from 0.1 to 32.0s.
Startup time:	3s, no preheating required.

Extended reading: How to calibrate HART pressure transmitters

Gauge pressure transmitter working principle

SMT3151 TGP-Gauge Pressure Transmitter / Transducer is a diffusion silicon pressure transmitter. The working principle of the diffused silicon pressure sensor is based on the piezoresistive effect.

Using the principle of piezoresistive effect, the pressure of the measured medium directly acts on the diaphragm of the sensor (stainless steel or ceramic).

Make the diaphragm produce a slight displacement proportional to the pressure of the medium. To change the resistance value of the sensor. Use electronic circuits to detect this change. And convert and output a standard measurement signal corresponding to this pressure.

More about : Pressure transmitter Working Principle.

Industrial Applications of Gauge Pressure Transmitter

Gauge pressure transmitter is the most commonly used detection instrument in industrial process control, which is widely used in various automatic control systems. Such as aerospace, military industry, petrochemical, chemical industry, oil well, electricity, shipbuilding, building materials, pipelines and many other industries.

It is generally used to measure pressure or absolute pressure in environments where the medium temperature is not too high, the corrosiveness is not strong, the viscosity is not high, and it is not easy to crystallize.

If low temperature, high temperature, corrosive medium measurement is required. Please contact our engineers for customization!

Mechanical and plant engineering
Chemical industry
Medical technology
Food and beverage
Oil and gas industry
Packaging and paper industry
Pharmaceutical industry

Explosion Proof Pressure Transmitter for Hazardous locations

Difference between absolute, gauge, and differential pressure

Comparison of absolute, gauge and differential pressure

Absolute pressure

Absolute pressure is referred to as the vacuum of free space (zero pressure). In practice, absolute piezoresistive pressure sensors, measure the pressure relative to a high vacuum reference, sealed behind its sensing diaphragm.

The vacuum has to be negligible compared to the pressure to be measured. Sino-Instrument’s absolute pressure sensors, offer ranges from 1 bar or even 700 mbar as well as barometric pressure ranges.

Gauge pressure

Gauge pressure is measured relative to the ambient atmospheric. The average atmospheric at sea level is 1013.25 mbar. Changes of the atmospheric, due to weather conditions, or altitude influences the output of a gauge pressure sensor.

A gauge pressure higher than ambient pressure is referred to as positive pressure. If the measured pressure is below atmospheric, it is called negative or vacuum gauge pressure. In general, a vacuum is a volume of space that is essentially empty of matter.

According to its quality vacuum is divided into different ranges such as an e.g. low, high and ultra high vacuum.

Differential pressure

Differential pressure is the difference between any two process pressures p1 and p2. Differential pressure sensors must offer two separate pressure ports, with a tube or thread. Sino-Instrument’s amplified pressure sensors, are able to measure positive and negative pressure differences. i.e. p1>p2 and p1<p2.

These sensors are called bidirectional differential pressure sensors, with ranges of e.g. -1…+1.0 bar or -2.5…+2.5 mbar. In contrast, unidirectional differential pressure sensor only operate in the positive range (p1>p2). E.g. from 0…1.0 bar or 0…2.5 mbar. And the higher has to be applied to the pressure port defined as “high pressure”.

Gauge Pressure VS Absolute Pressure

Gauge pressure refers to pipeline pressure. It refers to the pressure measured with pressure gauges, vacuum gauges, U-shaped tubes and other instruments, also called relative pressure). “Gauge pressure” starts from atmospheric pressure.
The pressure directly acting on the surface of the container or object is called “absolute pressure”. The absolute pressure value starts with absolute vacuum.
Absolute pressure actually refers to the gauge pressure plus the local atmospheric pressure (generally a standard atmospheric pressure can be 101.3Kpa).

Absolute pressure = gauge pressure + one atmosphere
If the unit is MPa, absolute pressure = gauge pressure + 0.1MPa

Transmitters can convert physical signals into electrical signals.
For example, our pressure transmitter can convert pressure signals into 4-20mA. Liquid level transmitter can convert liquid level signals into 4-20mA.

Gauges are generally mechanical. There is no output of electrical signals. For example, pressure gauges and liquid level gauges. The measurement results can be measured and read intuitively.

When selecting a pressure transmitter, the concept of pressure type is involved: absolute pressure, gauge pressure, negative pressure and differential pressure.

Absolute pressure transmitter measures the absolute pressure of the medium in the equipment. Its reference pressure is an absolute value of 0. It has nothing to do with atmospheric pressure. Therefore, there will be a vacuum sealed cavity on the low-pressure side of the pressure core.

Gauge pressure transmitter measures the pressure based on atmospheric pressure. One side of the pressure transmitter is connected to the atmosphere, and the other side is connected to the measured pressure, so the reference pressure side is open to the atmosphere. It is generally used to measure the liquid level of pipelines and non-pressure tanks.

If you pay close attention to the outer shell of some gauge pressure transmitters, it is not difficult to find some small holes on it. These vents are reserved to keep the reference side connected to the atmosphere.

More Featured Pressure Transmitters and Pressure Measurement Solutions

**SI-512H High Temperature Pressure Sensor**

**SI-706 Combined Pressure and Temperature Sensor-Dual function**

We at Sino-Inst manufacture and supply various types of gauge pressure transmitters for various industries. Customized production is available based on your measurement requirements, including pressure range, temperature, accuracy, signal output, mounting thread, material, etc.

If you need to purchase a gauge pressure transmitter or have any technical questions, please feel free to contact us.

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KimGuo11

Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.

Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.

drurylandetheatre.com

Industrial Pressure Transmitters

Posted on February 1, 2026 by KimGuo11

Industrial pressure transmitters for the process pressure measure, monitor and control application.

Industrial pressure transmitters are sensors with electrical transmission output for remote indication of pressure. Process transmitters differentiate themselves from pressure sensors through their increased range of functionality.

They feature integrated displays, offer high measuring accuracies and freely scalable measuring ranges. Communication is via digital signals, and waterproof and explosion-proof certifications are available. Through connection to diaphragm seals, they are suitable for the harshest operating conditions. Ideal for OEMs, process applications, water processing, and industrial pressure applications.

Sino-Inst offers a variety of pressure senors for industrial pressure measurement. If you have any questions, please contact our sales engineers.

Featured Industrial Pressure Transmitters

**Diffused silicon Gauge Pressure Transmitter**
A gauge pressure (GP) transmitter compares a process pressure against local ambient air pressure. Gauge pressure transmitters have ports to sample the ambient air pressure in real-time.

**Capacitive Gauge Pressure Transmitter**
Gauge pressure (GP) transmitters compare process pressure with local ambient air pressure. Gauge pressure transmitters have ports for real-time sampling of ambient air pressure.

**Explosion-proof Pressure Transmitter**
Explosion-proof Pressure transmitter, or explosion-proof pressure transducer, with the explosion-proof enclosure.
For applications in hazardous areas.

**Diaphragm Seal Pressure Transmitter**
When the process medium should not come into contact with the pressured parts of the measuring instrument. Diaphragm sealed pressure transmitters are used for pressure measurement.

**Hygienic / Sanitary Pressure Transmitter**
Also called Hygienic pressure Transmitters, or tri clamp pressure transmitter. Sanitary pressure Transmitters is used to food &beverage or pharmaceutical application.

**High-Temperature Pressure Transmitter**
**High-temperature pressure transmitters** with a 4-20mA output.
which has a temperature capability of over 850 °C and is not pyroelectric.

**Absolute Pressure Transmitter**
Absolute pressure transmitter with 4-20mA output for measuring pressure with absolute type reference. Absolute pressure (AP) transmitter is a measure of the ideal (complete) vacuum pressure.

**Hydrostatic pressure transmitter**
Hydrostatic pressure transmitter is used for fluid hydrostatic pressure measurement. With working static pressure up to 32Mpa, for liquid, gas or steam .

**Remote Diaphragm Seal Pressure Transmitter**
Remote seal pressure transmitter, with capillary and diaphragm seal, remote mount. Diaphragm seal systems protect pressure transmitters from hot, viscous, contaminated or corrosive media.

Sino-Inst also provides repair services for Industrial pressure transmitters. Such as WIKA, Rosemount, and other brands of pressure transmitters.

What is a smart pressure transmitter?

Digital smart pressure transmitter is pressure sensor with a 12-bit or higher microprocessor. Smart pressure transmitters are high performance microprocessor-based transmitters with flexibility. Pressure calibration and output, automatic compensation.

Smart pressure transmitter also called intelligent pressure transmitter.

The intelligent Industrial pressure transmitters consist of two parts: a smart sensor and a smart electronic board.

The smart sensor part includes: a capacitive sensor. A measuring diaphragm detection circuit. A temperature sensor, and a temperature compensation circuit.

The smart electronic board includes: a microcomputer controller. And the peripheral circuit, complete the pressure signal to 4 ~ 20mA dc conversion.

Smart Industrial pressure transmitter is used to measure the pressure of liquid, gas or steam. And then convert the pressure signal into 4 ～ 20mA DC signal output. The intelligent pressure transmitter produced by Sino-Inst can communicate with the HART communicator. It is widely used in weakly corrosive liquids in industrial pipelines, Gas and steam measurement and control systems.

Industrial pressure transmitters Working Principle

Principle and Application of Diffusion Silicon Pressure Transmitter

The pressure of the measured medium directly acts on the diaphragm of the sensor (stainless steel or ceramic). Causing the diaphragm to generate a micro-displacement proportional to the pressure of the medium. The resistance value of the sensor changes. The electronic circuit detects this change and converts and outputs a standard measurement signal corresponding to this pressure.

Principle of capacitive pressure transmitter

Capacitive pressure transmitter is mainly composed of capacitance sensor and circuit board. The sensor implements pressure-capacitance conversion. The circuit board converts the capacitance to a two-wire 4-20mA.

When the process pressure is applied to the isolation diaphragm from both sides (or one side) of the measuring chamber, it is transferred to the central diaphragm of the chamber through the silicone oil filling liquid. The central diaphragm is a diaphragm with tensioned edges.

Under the action of pressure, a corresponding displacement is generated. This displacement creates a change in differential capacitance!

And through the adjustment, oscillation and amplification of the electronic circuit board! Converted into 4-20mA signal output! The output current is directly proportional to the process pressure!

How Does a Pressure Transmitter Work?

Types of Pressure Transmitters

Depending on the type of pressure to be measured:

Pressure transmitter types include gauge pressure, absolute pressure, and differential pressure. Gauge pressure refers to the pressure that is less than or greater than atmospheric pressure based on the atmosphere. Absolute pressure refers to the absolute zero pressure as the reference and is higher than the absolute pressure. Differential pressure refers to the difference between two pressures.

According to the working principle of the Industrial pressure transmitters:

Strain Gauge Pressure Transducers
Capacitance Pressure Transducers
Potentiometric Pressure Transducers
Resonant Wire Pressure Transducers

Electrical Output of Pressure Transducers

Pressure transmitters are generally available with three types of electrical output. Millivolt, amplified voltage and 4-20mA. Below is a summary of the outputs and when they are best used.

Extended Reading: 4-20ma pressure transducer wiring diagram

Millivolt Output Pressure Transducers

A sensor with a millivolt output is usually the most economical pressure sensor. The output of a millivolt sensor is nominally about 30mV. The actual output is proportional to the input power or excitation of the pressure sensor. If the stimulus fluctuates, the output will change.

Because of this dependence on the level of excitation, a regulated power supply is recommended for millivolt sensors. Because the output signal is so low, the transducer should not be placed in an electrically noisy environment. The distance between the transducer and the reading instrument should also be kept relatively short.

Voltage Output Pressure Transducers

Voltage output transducers include integral signal conditioning, which provides higher output than millivolt transducers. The output is usually 0-5Vdc or 0-10Vdc. Although model-specific, the output of the transducer is usually not a direct function of the stimulus. This means that as long as the regulated power supply falls within the specified power range, it is usually sufficient. Because of their higher output levels, these sensors are not as susceptible to electrical noise as millivolt sensors and can therefore be used in more industrial environments.

4-20 mA Output Pressure Transducers

These types of sensors are also called pressure transmitters. Because 4-20mA signals are least affected by electrical noise and resistance in the signal line, these sensors are best used when signals must be transmitted over long distances. These sensors are typically used in applications where the lead must be 1000 feet or more.

Industrial Applications of Pressure Transmitters

Pressure transmitters are mainly used in the following areas:

Petroleum, petrochemical, chemical. Matching with throttling devices to provide accurate flow measurement and control. Measures pressure and level in pipes and tanks.
Electricity, city gas. And other companies and businesses require high stability and high precision measurement and other places.
Pulp and papermaking are used in places that require chemical-resistant liquids and corrosion-resistant liquids.
Steel, non-ferrous metals, and ceramics are used in furnace pressure measurement and other places that require high stability and high precision measurement. They are also used in places that require stable measurement under strict control (temperature, humidity, etc.).
Machinery and shipbuilding, used to strictly control the place where high precision is required for stable measurement.

Hydrostatic pressure for level measurement:

SMT3151TR Hydrostatic level transmitter-Rod Type

Pressure Transmitters VS Pressure Sensors VS Pressure Transducers

A pressure sensor is a device or device that can sense a pressure signal and convert the pressure signal into a usable output electrical signal according to a certain rule.

A pressure sensor usually consists of a pressure-sensitive element and a signal processing unit. According to different test pressure types, pressure sensors can be divided into gauge pressure sensors, differential pressure sensors and absolute pressure sensors. A pressure sensor is the core part of pressure transmitter.

In a pressure transducer, a thin-film or piezo-resistive pressure sensor is mounted on a process connection. The transducer converts pressure into an analog electronic output signal, typically as a millivolt per volt output. These signals are not linearized or temperature compensated.

A pressure transmitter has additional circuitry that linearizes, compensates, and amplifies the signal from a transducer. The different signal types are typically voltage signals (eg, 0 to 5 or 0 to 10 volts), milliamp (eg, 4 to 20 milliamp), or digital. The instrument then can transmit the signal to a remote receiver.

If you still don’t know how to choose the right pressure transmitter. Please feel free to contact our sales engineers. We will provide you with the best pressure measurement and control solution.

Guidelines for Troubleshooting Pressure Transmitters

Transmitter output signal is unstable or output is zero
High or low mA reading
The input pressure does not respond or the transmitter does not return to zero after the pressure is released.
The degree of pressure variable is low or high

When this happens, you should consider: Is the pressure source itself stable? The degree of anti-interference ability of the instrument or pressure sensor. Is the sensor wiring normal? The sensor itself is vibrating and the cause of the failure. Is the polarity of the power supply reversed?

Check the degree of pressure variable; make 4-20mA output adjustment.

Check the transmitter’s power supply voltage, calibration equipment and set values (4mA and 20mA points). Check whether the pressure interface is leaking or blocked. Check the wiring mode and power supply. If normal, check if the sensor has zero output. Or Perform a simple pressurization to see if the output changes. If there is a change, the sensor is not damaged.

Check if pressure transmission is blocked; check calibration equipment and adjust sensors; check vehicle damping and electromotive force interference.

Frequently
Asked
Questions

Help Center

1. Do a 4-20mA trimming first to calibrate the D / A converter inside the transmitter. Since it does not involve sensing components, no external pressure signal source is required.

2. Do a full fine-tuning again to make the 4-20mA, digital reading coincide with the pressure signal actually applied. So a pressure signal source is needed.

3. Finally, do the re-ranging, and adjust the analog output 4-20mA to match the external pressure signal source. Its role is exactly the same as that of the zero (Z) and range (R) switches on the transmitter housing.
The communicator can change the range of the intelligent pressure transmitter. And can adjust the zero point and the range without inputting a pressure source. However, this method cannot be called calibration and can only be called “setting the range”. True calibration requires a standard pressure source input to the transmitter.

Adjusting the range (LRV, URV) without using a standard is not calibration. And ignoring the input part (input transmitter pressure) for output adjustment (transmitter conversion circuit) is not a correct calibration. Furthermore, the relationship between the pressure and differential pressure detection components, the A / D conversion circuit, and the current output is not equal. The purpose of calibration is to find the changing relationship between the three.
Emphasize one point:
Only when the input and output (input transmitter pressure, A / D conversion circuit, loop current output circuit) are debugged together, can it be called a true calibration.

First of all, the parameters that must be seen when purchasing a pressure transmitter are:
Pressure range. Range. Measurement medium. Installation method-threaded flange clamps, etc. Installation dimensions. Temperature. Whether with display. Whether with HART protocol. Output type. Current output or voltage output. Explosion-proof level, protection level. Accessories. Mounting bracket.
The above parameters will affect the price of the pressure transmitter.
Sino-Inst, as the manufacturer of pressure transmitter, offer you with the best price.

The input of the pressure transmitter is a pressure signal. The function of the pressure transmitter is to convert the pressure signal input from the outside into a current or voltage signal.

A pressure transmitter is a device that converts pressure into pneumatic or electric signals for control and remote transmission.

It can convert physical pressure parameters such as gas and liquid sensed by the load cell sensor into standard electrical signals (such as 4~20mADC, etc.). Measurement, indication and process adjustment are carried out by supplying secondary instruments such as indicating alarms, recorders and regulators.

Related Products

**High Frequency Dynamic Pressure Sensor**

**Extended Diaphragm Seal DP Level Transmitter**

**Remote Seal Differential Pressure Transmitter**

**Differential pressure(DP) level transmitter**

**Flange Mounted Differential Pressure Transmitter**

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Sino-Inst offers over 20 industrial pressure transmitters.
A wide variety of industrial pressure transmitters options are available to you. Such as free samples, paid samples.
Sino-Inst is a globally recognized manufacturer of industrial pressure transmitters, located in China.
Sino-Inst sells through a mature distribution network that reaches all 30 countries worldwide.
Industrial pressure transmitters products are most popular in Europe, Southeast Asia, and Mid East. You can ensure product safety by selecting from certified suppliers. With ISO9001, ISO14001 certification.

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KimGuo11

drurylandetheatre.com

Diaphragm Seal Pressure Transmitters

Posted on February 1, 2026 by KimGuo11

Diaphragm Seal Pressure Transmitters work with Diaphragm Seals for those harsh working conditions. The purpose of the diaphragm seal is to isolate the pressure sensor from the process medium.

The diaphragm seal makes measuring pressure safer and more reliable. It is ideal for protecting pressure process transmitters even under harsh working conditions. The diaphragm seal can isolate the pressure sensor from the process medium. No matter absolute pressure or differential pressure measurement. Mounting with capillary and flange, Diaphragm Seal pressure transmitter can measure pressure, liquid level and flow.When the environment is extremely hot or cold, or when the process connection is difficult to connect to the measuring instrument. When the measured medium is corrosive, sticky, sticky or easily cured. Or when the process is not chemically compatible with the instrument material. It is recommended to use a diaphragm seal.

Sino-Inst offers a variety of Diaphragm Seal Pressure Transmitters for industrial pressure measurement. If you have any questions, please contact our sales engineers.

Featured Diaphragm Seal Pressure Transmitters

Remote Diaphragm Seal Pressure Transmitter

What is a diaphragm seal?

Diaphragm seals, also known as chemical seals or remote seals, are used for pressure measurements when the process medium should not come into contact with the pressurised parts of the measuring instrument.

A diaphragm seal has two primary tasks:

Separation of the measuring instrument from the process medium
Transfer of the pressure to the measuring instrument

Advantages of diaphragm seals

Diaphragm seals offer the advantage that the “contact surface” between pressure medium and diaphragm is relatively large. Thus ensuring accurate pressure measurement, especially for very low pressures (< 600 mbar). Furthermore, they can be easily dismounted, e.g. for cleaning or calibration purposes.

Rosemount 1199

Rosemount 1199 remote transmission diaphragm system provides the world’s most extensive product variety and specifications to meet the requirements of various measurements and applications.

There are the following types of remote transmission differential pressure / level transmitters:
1) PFW flat type remote transmission device
2) RTW thread installation type remote transmission device
3) EFW inserted barrel remote transmission device
4) RFW flange mounted remote transmission device
5) SCW hygienic remote transmission device

The 1199 remote diaphragm can be assembled to Sino-Inst differential, gauge, and absolute pressure transmitters and liquid level transmitters.

We can learn more about Rosemount 1199 remote diaphragm.

How do diaphragm seals work?

Basically, diaphragm seals are used in all pressure measurement processes to avoid direct contact between the measuring instrument and the medium during this process.

In addition, if the measuring point cannot be installed or read because the measuring point is located in a hard-to-reach location, a diaphragm seal can also be used.

In both cases, the applied pressure is transferred to the measuring instrument through the system fill fluid in the diaphragm seal housing.

The diaphragm of the seal can be made of different materials, such as stainless steel, Hastelloy, Monel or tantalum. In addition, coatings with ECTFE, PFA or gold can also be used.

We can provide the best diaphragm seal design, materials, system fill fluid and accessories for each application. The combined configuration of the pressure measuring instrument and the diaphragm seal is mainly determined by the special application conditions of the diaphragm sealing system.

Differential Pressure Transmitter Installation Guide

Diaphragm type pressure transmitter working principle

Diaphragm pressure transmitter is an automated instrument that measures fluid pressure in the industrial field.

It is mainly composed of pressure measuring probe, capillary tube, filling liquid and pressure transmission head.
One end of the pressure measuring probe is provided with an elastic metal diaphragm
When the pressure acts directly on the surface of the measuring diaphragm, the diaphragm will have a slight deformation.
The high-precision circuit on the measuring diaphragm transforms this tiny deformation into a highly linear voltage signal proportional to the pressure and also proportional to the excitation voltage.
Then use a special chip to convert this voltage signal into an industry standard 4-2OmA current signal or 1-5V voltage signal.
Because the measuring diaphragm adopts standard integrated circuit, which contains linear and temperature compensation circuits, it can achieve high precision and high stability.
The transmission circuit adopts a special two-wire system chip, which can ensure the output of a two-wire 4-20mA current signal, which is convenient for field wiring.

When to use diaphragm seal ?

The diaphragm seal pressure transmitter is suitable for the following working conditions:

The high temperature medium needs to be isolated from the transmitter.
The measuring medium has a corrosive effect on the sensitive components of the transmitter.
Suspended liquid or high viscosity medium.
The measured medium solidifies or crystallizes due to changes in the environment or process temperature.
Replacing the measured medium requires strict purification of the measuring head.
The measuring head must be kept clean and hygienic.
Liquid level measurement of sealed pressure vessel.

Difference between bourdon tube and diaphragm pressure gauge:

SI-D100 Diaphragm Pressure Gauge

Frequently
Asked
Questions

Help Center

The remote seal is used to prevent the medium in the pipeline from directly entering the pressure sensor assembly in the pressure transmitter. It is connected to the transmitter by a capillary filled with fluid. As a result, they’re often used in refining, petrochemical, and chemical plants.

Diaphragm pressure gauge consists of a diaphragm isolator and a universal pressure gauge to form a system pressure gauge. The spring tube is evacuated by special equipment. And fill people with irrigation fluid. Seal it with a diaphragm. When the pressure P of the measured medium acts on the diaphragm, it deforms. The working fluid filled in the compression system makes the working fluid form a △ P equivalent to P, with the help of work. The conduction of the liquid causes a corresponding elastic deformation-displacement at the free end of the elastic element (spring tube) in the pressure meter. According to the working principle of the pressure instrument matched with it, the measured pressure value is displayed.

Diaphragm pressure gauges consist of a system of diaphragms and universal pressure gauges. Diaphragm pressure gauges and equipment are mainly connected with threaded connections, flange connections and sanitary clamps. Diaphragm pressure gauges are suitable for measuring the pressure of medium with strong corrosion, high temperature, high viscosity, easy to crystallize, easy to solidify, and solid floats, as well as occasions where the measurement medium must be avoided from entering the general-purpose pressure meter and to prevent the accumulation of sediment and easy to clean.

The characteristics of the filling fluid determine the performance of the sealing system to a large extent, both in response time and temperature to the heat dissipation conditions.
The initial consideration in choosing a sealed diaphragm to fill fluid is the media compatibility of the process.
Glycerin, silicone oil and halogenated carbon are the most commonly used sealed diaphragm filling fluids.
In general there are three ways to fill a diaphragm seal:
1. Filling a diaphragm seal after assembly of the seal to the instrument
2. Filling a diaphragm seal before assembly of the seal to the instrument
3. Filling a diaphragm seal with a capillary between the seal and the instrument

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Sino-Inst is a manufacturer of Diaphragm Seal Pressure Transmitters.

Sino-Inst offers over 20 Diaphragm Seal Pressure Transmitters at best price. About 50% of these are Pressure level Transducer, 40% are Differential Pressure transmitters, and 40% are Diaphragm Seal Pressure transmitters.
A wide variety of Diaphragm Seal Pressure Transmitters options are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of Diaphragm Seal Pressure Transmitters, located in China. Sino-Inst sells through a mature distribution network that reaches all 50 states and 30 countries worldwide. Diaphragm Seal Pressure Transmitters 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.

Request a Quote

Please enable JavaScript in your browser to submit the form

KimGuo11

drurylandetheatre.com

Diaphragm Seal Pressure Transmitter － Flush Flanged

Posted on January 28, 2026 by KimGuo11

The flush flanged diaphragm seal pressure transmitter uses a diaphragm directly welded to the mounting flange, working in conjunction with an inline pressure transmitter to protect against the effects of high and low temperatures, corrosive, clogging, or erosive processes.

Get a Quote

Sino-Inst offers a variety of Diaphragm Seal DP/Pressure Transmitters for industrial pressure measurement. If you have any questions, please contact our sales engineers.

Features
Specifications
Applications

Features of Diaphragm Seal Pressure Transmitter

Flange installation; flange size and standards can be customized.
Diaphragm isolation technology.
Two-wire system, 4-20mA analog output, HART protocol digital communication.
Intelligent LCD display with backlight.
Large diaphragm, fully welded seal, long-term reliability and durability.
Corrosion-resistant diaphragm options available (tantalum, HaC, 316L, 316L PTFE sprayed).
Especially suitable for high-temperature viscous liquids.
HART communication function available.

Specifications of Diaphragm Seal Pressure Transmitter

Measuring medium:	Liquid or gas (compatible with contact material)
Pressure range:	-100kPa～0～10MPa (see range selection table for details)
Pressure method:	Gas pressure, absolute pressure
Medium temperature:	-40～130℃, other high temperatures can be customized up to 60℃
Connection time:	20ms
Accuracy class:	±0.5%FS
Indicator accuracy:	0.05%FS LCD (with backlight) display
Temperature compensation:	-20～80℃
Stability performance:	±0.2%FS/year
Temperature drift:	±0.02%FS/℃ (within temperature compensation range)
Explosion-proof type:	Explosion-proof type ExdbⅡCT6Gb; Explosion-proof dust type ExtbIIICT80℃Db; Intrinsically safe type ExiaⅡCT6Ga (4～20mA/4～20mA HART output only); Dust intrinsically safe type ExiaD20T80℃ (4～20mA/4～20mA HART output only);
Protection class:	IP66;

Applications

The Flush Flanged Diaphragm Seal Pressure Transmitter uses a standard flange as its interface, allowing for on-site flange installation. Because the pressure-bearing diaphragm is exposed and directly senses the pressure, it is easy to clean and meets harsh operating conditions such as moisture resistance, waterproofing, and explosion protection.

This series of products is widely used in industrial process control, petroleum, chemical, and metallurgical industries, as well as in applications involving viscous media containing particles.

High/low temperature fluids;
Highly corrosive/high viscosity fluids;
The fluids which may cause clogging of impulse piping in the low temperature;
Toxic fluids;
The fluids containing suspended solids which are deposited in the impulse piping and may cause clogging.

Extended reading: Featured Diaphragm Seal Pressure Transmitters

Diaphragm flange material selection

The biggest advantage of the Diaphragm Seal Pressure Transmitter is the availability of various diaphragm materials. Commonly used diaphragm materials include SUS316L stainless steel, tantalum, Hastelloy, Monel alloy, pure titanium, and F4 alloy.

Choosing the right material means considering both its corrosion resistance and cost-effectiveness. For example, tantalum and Hastelloy diaphragms offer excellent corrosion resistance but are expensive, making them suitable only for highly corrosive environments; other inexpensive materials are not suitable.

The table below introduces several commonly used corrosion-resistant materials suitable for corrosive media for your reference.

Corrosive medium	Tin bronze (QSn6.5-0.4)	SUS316	Pure tantalum (Ta)	Monel (Ni70Cu30)	Hastelloy (HC)	Polytetrafluoroethylene (F4)
Sulfuric acid (H2SO4)	V	△	○	V	V	V
Nitric acid (HNO3)	╳	V	○	╳	V	V
Hydrochloric acid (HCI)	△	╳	○	╳	V	V
Phosphoric acid (H3PO4)	V	V	○	V	V	V
Acetic acid (CH3COOH)	V	V	○	V	○	V
Caustic soda (NaOH)	△	○	△	○	○	V
Soda ash (Na2CO3)	○	○	○	○	V	V
Baking soda (NaHCO3)	V	○	○	○	○	V
Chlorine (CI)	Dry: V	Dry: V	○	Dry: V	V	V
	Wet: ╳	Wet: ╳	Wet: ╳
Bromine (Br2)	Dry: △	Dry: ╳	○	Dry: ○	○	V
	Wet: ╳	Wet: △	Wet: ╳
Ammonia (NH3)	╳	V	╳	╳	○	V
Seawater (30% NaCI)	V	V	○	○	○	V

Explanation of symbols: ○ ——best; △ ——conditional use; V——can be used;

Extended reading: Common Pressure Sensor Applications

What is a diaphragm seal pressure transmitter?

The diaphragm seal pressure transmitter is a flange-type pressure transmitter. This type of pressure transmitter assembles diaphragm seals to field transmitters for the purpose of measuring pressure, pressure or level.

What is a diaphragm seal?

Diaphragm Seals, also known as Chemical Seals or Gauge Isolators, are used to isolate pressure instrumentation, like pressure gauges, pressure transmitters, pressure switches, level transmitters, and more, from process media that is hot, corrosive, clogging, or otherwise damaging to the pressure instrument.

A diaphragm seal has two primary tasks:

Separation of the measuring instrument from the process medium
Transfer of the pressure to the measuring instrument

What is a remote seal?

Extended reading: SI-703 Flush Diaphragm Pressure Sensor

FAQ

A pressure level transmitter is a device that works on the principle that static pressure is proportional to liquid level height. It is essentially a device that combines the functions of a pressure sensor and a level gauge.

The transmitter uses an advanced isolated diffused silicon sensitive element or a ceramic capacitor pressure sensitive sensor. The measured static pressure of the liquid is converted into an electrical signal.

This process is temperature compensated and linearly corrected, and the final output is a standard electrical signal, common forms are 4~20mA or 1~5VDC, etc.

Extended reading: Flat Pressure Sensor for High Viscosity Fluids

The pressure gauge is an instrument that uses elastic elements as sensitive elements to measure and indicate pressure higher than the ambient pressure. It is used in almost all industrial processes and scientific research fields.

Pressure transmitter is a device that converts pressure into pneumatic or electric signals for control and remote transmission.

The differences between pressure transmitter and pressure gauge are:

The accuracy of the standard instrument required for pressure transmitter calibration is much higher than the accuracy of the standard instrument required for pressure gauge.
The pressure gauge only needs to calibrate a pair of input and output relationships. The pressure transmitter may need to calibrate the relationship between input and communication data.
Pressure gauge calibration must have corresponding metrological qualifications. Pressure transmitters are generally not required except for production and new construction.
The pressure gauge has poor accuracy and no output. It cannot be operated with a hand operator. Generally, 5 points are calibrated. The back and forth difference is different. The intelligent pressure transmitter generally only needs to calibrate the zero point and full scale.
The output of the pressure gauge is a scale indication, and its own display capability. The pressure transmitter is a current output and must be connected to an ammeter display of the corresponding accuracy level.

Extended reading: extrusion melt pressure transducer

A diaphragm seal system consists of a pressure instrument, a fill liquid, and a diaphragm seal, either direct-mount or capillary.

Diaphragm seals are used to seal and protect instruments from process media. The flexibility of the seal lies in the fact that the diaphragm securely seals the contents and penetrates the instrument to accurately measure pressure.

Diaphragm seals are often used in conjunction with pressure transmitters. This combination can be used in extremely harsh environmental conditions.

The fact that they can isolate instruments from any kind of toxic and reactive chemicals makes them particularly useful devices.

Diaphragm-sealed pressure transmitters are used when the medium is corrosive or will corrode the internal parts of the transmitter (for example, ammonia will corrode the copper in the transmitter).

Extended reading: High accuracy pressure transducers

Sino-Inst is Flush Flanged Diaphragm Seal Pressure Transmitters manufacturer in China. We offer all types of Pressure Level Transmitters. Like Direct Mounted, flange-mounted, single flange, double flange, Remote Diaphragm Seals, High Static, Digital Remote.

Most of our Diaphragm Seal Pressure Transmitters are used in oil, liquids, DP transmitters, flow measurement, level measurement (like the ultrasonic level measurement), density, and other process variables.

You can ensure product safety by selecting from a certified supplier with ISO9001, ISO14001 certification. We will share more about instrument calibration, like the flow transmitter calibration.

Request a Quote

Please enable JavaScript in your browser to submit the form

KimGuo11

drurylandetheatre.com

Flange Mounted Differential Pressure Transmitter

Posted on January 26, 2026 by KimGuo11

The Flange Mounted Differential Pressure Transmitter is based on an intelligent differential pressure transmitter and features a flush-mounted or extended flange. It is suitable for measuring the level, differential pressure, and density of liquids that are prone to crystallization or sedimentation. Equivalent to model EJA210E.

Can be directly installed on tanks or pipelines. It is used for measuring high-temperature, easily solidifying or crystallizing, suspended solids-containing, highly viscous, highly corrosive, or other media that require hygienic conditions and cannot be contaminated.

Sino-Inst offers a variety of flange-mounted DP transmitters for industrial pressure measurement. If you have any questions, please contact our sales engineers.

More DP Transmitters

Sino-Inst Flange Mounted Differential Pressure Transmitter uses advanced microprocessing technology and digital communication technology. It outputs a 4~20 mA DC signal corresponding to the measured differential pressure. It can also be configured with the HART protocol.

Flange Mounted Differential Pressure Transmitter Features:

Used to measure the differential pressure of corrosive and non-corrosive gases, steam and liquids;
Using a stainless steel diaphragm;
Applicable to various hazardous places;
Output linear DC current proportional to the differential pressure value;
Provide various isolation diaphragms to meet special applications, such as liquid level measurement, corrosive media;
High measurement accuracy, 0.1%FS, 0.5%FS;
Extensible measurement range;
Aluminum and stainless steel housing;
With intrinsically safe explosion-proof and isolated explosion-proof capabilities. Can be used in various hazardous places.

Extended reading: Smart Differential Pressure Transmitter

Specification of Flange Mounted Differential Pressure Transmitter

Model	Transmitter type
SMT3151LT	Flange Mounted Differential Pressure Transmitter
Code	Scale range
4	0-4.0～40kPa(0-400～4000mmH2O)
5	0-20～200kPa(0-2～20mH2O)
6	0-70～700kPa(0-7～70mH2O)
7	0-210～2100kPa(0-21～mH2O)
Code	Output form
E	Linear output 4-20mAdc
SF	Linear output 4-20mAdc +HART signal
F	MODBUS-485 signal
Code	Flange standard (high pressure side flange)
A	ANSI American Standard (HG20615)
D	DIN European Standard (HG20592)
Code	Process connection size
ANSI American Standard (HG20615)	DIN European Standard (HG20592)
25	1”	DN25
40	1.5”	DN40
50	2”	DN50
80	3”	DN80
0	4”	DN100
Code	Process connection pressure rating
ANSI American Standard (HG20615)	DIN European Standard (HG20592)
A	150LB	PN16/25
B	300LB	PN40
C	600LB	PN64
D	900LB	PN100
Code	High pressure side diaphragm
A	316 stainless steel
B	Hastelloy C
C	Monel
D	Tantalum
E	Titanium
F	Special Requirements
Code	High pressure side insert tube length	High pressure side insert cylinder material
A	0 mm	None
B	50 mm	316L Stainless steel
C	150 mm	316L Stainless steel
D	200 mm	316L Stainless steel
Code	High pressure side filling fluid
D	General silicone oil （-40~104℃）
F	High temperature silicone oil （-40~304℃）
S	Inert liquid （-40~204℃）
Low pressure side structural material	Flange (joint)	Exhaust/drain valve	Isolation diaphragm	Sensor filling fluid
22	316 Stainless steel	316 Stainless steel	316 Stainless steel	Silicone oil
23	316 Stainless steel	316 Stainless steel	Hastelloy C	Silicone oil
24	316 Stainless steel	316 Stainless steel	Monel	Silicone oil
25	316 Stainless steel	316 Stainless steel	Tantalum	Silicone oil
33	Hastelloy C	Hastelloy C	Hastelloy C	Silicone oil
35	Hastelloy C	Hastelloy C	Tantalum	Silicone oil
44	Monel	Monel	Monel	Silicone oil
S2	A remote transmission device (with a remote transmission device on the low-voltage side)
Code	Shell material	Conduit inlet dimensions
A	Low copper aluminum alloy polyurethane coating	M20×1.5
B	Low copper aluminum alloy polyurethane coating	1/2-14 NPT
C	Stainless steel	M20×1.5
D	Stainless steel	1/2-14 NPT
Code	Optional parts
M1	0～100% Linear indicator head
M4	LCD multi – power digital display head
D1	Side discharge valve at the top (only for the low pressure side of the low pressure side without remote transmission)
D2	Side discharge valve at the top (only for the low pressure side of the low pressure side without remote transmission)
Da	Flameproof ExdIIBT5Gb;(explosion-proof certificate no. : CE16.1163)
Fa	Intrinsically safe ExiaIICT4 / T5 / T6Ga;(explosion-proof certificate no. : CE15.2354X)
CX	With corresponding 316 flushing ring

Extended Reading:

Applications

The Flange Mounted Differential Pressure Transmitter can accurately measure the liquid level and density of various containers. There are two types of flat flange and insert flange. It is suitable for high-viscosity medium or suspended liquid measurement.

Viscous medium at high temperature;
Easily crystallized medium;
Precipitation medium with solid particles or suspended matter;
Strongly corrosive or highly toxic medium;
It can eliminate the leakage of the pressure guiding pipe and pollute the surrounding environment. It can avoid the instability of the measurement signal when the isolation liquid is used. The tedious work of frequently supplementing the isolation liquid is required;
Continuously and accurately measure the interface and density;
The remote transmission device can avoid the mixing of different instantaneous media so that the measurement results truly reflect the actual situation of process changes;
Places with high sanitation requirements;
Such as in the production of food, beverage, and pharmaceutical industries. Not only the transmitter contacting the media parts meet hygienic standards, but also should be easy to wash. To prevent cross-contamination of different batches of media.

Pressure level transmitter is good for level measurement. Most of the time, we use submersible hydrostatic level sensor for the level measurement. When you can not use the probe of hydrostatic level sensor, you can try with this pressure level transmitter. Pressure level transmitter, is one type of DP level measure instrument, with the diaphragm.

More

The SMT3151LT differential pressure level transmitter is a new type of differential pressure transmitter manufactured using advanced technology and equipment. Equipped with dual remote seals, it can be used for continuous measurement of liquid level, flow rate, and differential pressure. It offers particular advantages in applications involving sealed storage tanks.

More

Flange Mounted Differential Pressure Transmitter Working principle

1. Headcover; 2. Head; 3. Metal bulkhead; 4. Shell; 5. Nameplate label; 6. Explosion-proof joint; 7. Terminal block; 8. Head cover; 9. Drain valve; 10. Bolt; 11. Clamp; 12. Sensor seal; 13. Sensor; 14. Nut; 15. Welded pipe joint assembly

Differential pressure transmitters utilize the pressure difference generated by the liquid’s own gravity to measure the liquid level in a container.

Flange-mounted differential pressure transmitters are directly installed on pre-existing flanges at the bottom of pipes or containers, contacting the liquid through an isolation diaphragm.

When the diaphragm is subjected to pressure, it undergoes slight deformation. The displacement of the diaphragm changes with the differential pressure. This change is precisely converted by an amplification circuit into a 4-20mA DC two-wire current, voltage, or digital HART output signal, thus achieving pressure measurement and transmission.

The high-pressure side measuring tube is always filled with the medium, maintaining constant pressure. The low-pressure side measuring tube forms a communicating vessel with the container, and its pressure changes linearly with the liquid level in the container.

Let △P be the differential pressure signal received by the transmitter, P0 be the internal pressure of the container, P+ be the pressure on the positive pressure side of the transmitter, and P- be the pressure on the negative pressure side of the transmitter. Let ρ be the density of the liquid in the container, g be the acceleration due to gravity, h1 be the height from the process zero point to the upper pressure tap of the container, h2 be the process liquid level in the container, and h be the height from the transmitter to the process liquid level zero point.

Then:
P+ = P0 + ρgh1 + ρgh
P- = P0 + ρgh2 + ρgh
△P = P+ – P- = ρgh1 – ρgh2

When the liquid level changes from h2=0 to h2=h1, the differential pressure measured by the transmitter changes from its maximum value to △P=0. By configuring the transmitter, the output current changes from 4mA to 20mA.

Single flange vs Double flanges differential pressure level transmitter

In principle: all are differential pressure transmitters + flange guide pressure;
In terms of structure: the single flange liquid zd position transmitter has only one flange diaphragm box connected to the high pressure side, and the low pressure side to the atmosphere. The double flange liquid level transmitter is high and low pressure side through oil-filled capillary It is connected with two flanged membrane return boxes. There is also a capillary. The single flange transmitter is installed below, and a capillary is drawn from the low pressure side of the single flange transmitter to the upper flange membrane box.
In terms of engineering applications: all can only measure the liquid level of fixed density. The single-flange transmitter can only be used for the liquid level of atmospheric equipment that can be imagined with the atmosphere. The double-flange transmitter can be suitable. Answer: Use closed equipment kettle to measure liquid level;
From the economical point of view, the double flange is definitely more expensive than the single flange. After all, there is one more flange capsule and capillary.

**Piezoresistive Differential Pressure Transmitter**
Piezoresistive Differential Pressure Transmitter utilizes the piezoresistive effect of semiconductor silicon materials. Realize accurate measurement of differential pressure.

**Smart Differential Pressure Transmitter**
Smart Differential Pressure Transmitter measures industrial differential pressure. Can Works with diaphragm seals, capillary, HART. Outputs standard signals (such as 4 ~ 20mA, 0 ~ 5V).

SMT3151DP Smart Differential Pressure Transmitter

Posted on January 26, 2026 by KimGuo11

The SMT3151DP Smart Differential Pressure Transmitter utilizes a single-crystal silicon sensor with German MEMS technology, offering higher measurement accuracy. It outputs standard signals (e.g., 4-20mA, 0-5V) and can also be configured with RS485 Modbus RTU or HART protocols.

The single-crystal silicon sensor core features a dual-beam suspension design, significantly improving accuracy and resistance to unilateral and bilateral overload. A built-in intelligent signal processing module achieves perfect integration of static pressure and temperature compensation. This enhances measurement accuracy and long-term stability across a wide range of static pressure and temperature variations.

Sino-Inst offers a variety of smart differential pressure sensors for industrial pressure measurement. If you have any questions, please contact our sales engineers.

More DP Transmitters

Features
Specifications
Datasheet
Order Guide

Features

Blue and white custom housing smart differential pressure transmitter

Output signal 4-20mA output+RS485/HART communication;
0.075%FS high accuracy, millisecond-level ultra-fast response;
Built-in three-button quick operation for on-site adjustment;
Self-diagnosis capability;
Range coverage is 0-0.1KPa~41.0MPa;
Good stability, high precision, adjustable damping, strong resistance to one-way overload.
Explosion-proof housing structure.
LCD display;
IP67 protection rating;
Intelligent static pressure compensation and temperature compensation protect the transmitter from the effects of temperature, static pressure, and overpressure, controlling the overall measurement error at the site within the specified parameters;
High static pressure resistance, up to 40MPa;

Extended reading: How to calibrate HART pressure transmitters

Technical Specifications

Measurement Range	1KPa, 4KPa, 40KPa, 100KPa, 400KPa, 4MPa, 40MPa
Single-Side Overpressure	16MPa
Dual-Side Static Pressure	16MPa 25MPa 40MPa
Measurement Accuracy	±0.075%, ±0.1%, ±0.5% (including linearity, hysteresis, and repeatability from zero)
Measured Medium	Gas, Liquid, Steam
Output Signal	4~20mA DC+RS485/HART protocol
Power Supply	General 10.5~45VDC, intrinsically safe explosion-proof 10.5-26VDC
Power Line Spacing	15cm and above (avoid parallel wiring)
Saturation Current	Upper limit 20.8mA, lower limit 3.8mA
Alarm Current	Upper limit 22.8mA, lower limit 3.6mA (mode adjustable)
Adjustment Function	Zero and full-scale points can be adjusted locally via the three buttons on the top of the casing or remotely via configuration software
Zero Shift	Can be shifted within the range of -20% to +20% of the maximum range
Output Method	Linear output Square root output (can be remotely adjusted via configuration software)
Operating Temperature	-40~85℃
Measured Medium Temperature:	-40℃~120℃ (High temperature customizable)
Diaphragm Material	316L stainless steel/Hastelloy alloy/Tantalum diaphragm/Gold-plated diaphragm
Position Effect	Approximately 200Pa between horizontal and vertical positions
Response Time	10ms
Static Pressure Effect	< 0.05%FS/10MPa
Overpressure Effect	< 0.05%FS/10MPa
Stability	≤0.03%FS/year
Power Supply Effect	< 0.005%FS/V
Explosion-Proof Rating:	Exd Ⅱ CT6 Gb, Exia Ⅱ CT6 Ga
Enclosure Protection Rating:	IP67

SMART Differential Pressure Transmitter Datasheet

SM3151DP-Differential-Pressure-Transmitter Download

Order Guide

Use object: liquid, gas, or steam

Model	Transmitter type
DP	Pressure transmitter
HP	Absolute pressure transmitter
Code	Scale range
2	0-0.10～3.5kPa(0-10～350mmH2O)
3	0-0.8～8.0kPa(0-80～800mmH2O)
4	0-4.0～40kPa(0-400～4000mmH2O)
5	0-20～200kPa(0-2000～20000mmH2O)
6	0-70～700kPa(0-0.7～7kgf/cm2)
7	0-210～2100kPa(0-2.1～21kgf/cm2)
8	0-700～7000kPa(0-7.0～70kgf/cm2)
9	0-2.1～21MPa(0-21～210kgf/cm2)
0	0-4.1～41MPa(0-41～4100kgf/cm2)
Code	Output form
E	Linear output 4-20mAdc
SF	Linear/square root output 4-20mAdc +HART signal,，Full function buttons on site
F	MODBUS-485 signal

Structural materials	Flange connector	Exhaust/Drain valve	Isolation diaphragm	Filling liquid
22	316 Stainless steel	316 Stainless steel	316 Stainless steel	Silicone oil
23	316 Stainless steel	316 Stainless steel	Hastelloy C	Silicone oil
24	316 Stainless steel	316 Stainless steel	Monel	Silicone oil
25	316 Stainless steel	316 Stainless steel	Tantalum	Silicone oil
33	Hastelloy C	Hastelloy C	Hastelloy C	Silicone oil
35	Hastelloy C	Hastelloy C	Tantalum	Silicone oil
44	Monel	Monel	Monel	Silicone oil
Code	Shell material	Conduit inlet dimensions
A	Low copper aluminum alloy polyurethane coating	M20×1.5
B	Low copper aluminum alloy polyurethane coating	1/2-14 NPT
C	Stainless steel	M20×1.5
D	Stainless steel	1/2-14 NPT

Code	Pressure connection
L1	1/4NPT-18 Internal thread（excluding waist joint standard）
L2	1/2NPT-14 Internal thread
L3	M20×1.5 External thread
Code	Optional parts
M4	LCD multi – power digital display head
B1	Pipe bending bracket
B2	Plate bending bracket
B3	Pipe mounting bracket
C02	M20×1.5 nut and Φ 14 pressure short tube
C12	1/2NPT-14 external thread and Φ14 pressure short tube
C22	1/4NPT-18 external thread and Φ14 pressure short tube
C32	1/4NPT-18 to M20×1.5 external thread
C42	1/2NPT-14 to M20×1.5 external thread
C43	1/2NPT-14 to 1/4NPT-18 internal thread
C44	1/2NPT-14 to 1/2NPT-14 external thread
C45	1/2NPT-14 to G1/2 external thread
D1	The side discharge valve is on the upper part
D2	The side discharge valve is on the upper part
X1	Oil ban
Da	Flameproof ExdIIBT5Gb;(explosion-proof certificate no. : CE16.1163)
Fa	Intrinsically safe ExiaIICT4/T5/T6Ga;(explosion-proof certificate no. : CE15.2354X)

Working principle of SMART differential pressure transmitter

The intelligent differential pressure transmitter uses a single-crystal silicon piezoresistive sensor as its core component. When pressure is applied to the sensor, the resistance of the single-crystal silicon changes, which is converted into an electrical signal by the circuit, and then digitally processed to output a standard signal (such as 4-20mA or a digital signal).

Its intelligent feature lies in its built-in microprocessor, which can perform temperature compensation, linear correction, and fault diagnosis, ensuring high measurement accuracy and stability.

The SMT3151DP intelligent differential pressure transmitter integrates differential pressure measurement, display, and signal output functions. This intelligent differential pressure transmitter is used to measure the level, density, flow rate, and pressure of liquids, gases, or vapors.

Smart Differential Pressure Transmitter Applications

SMT3151DP smart differential pressure transmitter is suitable for applications like:

Flow measurement;
- The differential pressure transmitter is combined with the throttling device (like the orifice plate). To convert the flow rate according to the differential pressure value, generated before and after the throttling device.
Level monitoring;
- Measuring the height of the liquid by the pressure difference, generated by the gravity of the liquid itself.
Steam measurement;
Filter or pump differential pressure;
For Monitoring Hydronic HVAC Systems.
Critical process monitoring.

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Generally used in liquid, gas or steam differential pressure, flow measurement. The medium temperature is not too high, corrosion is not strong, viscosity is not high, not easy to crystallize and other environments.

If the working static pressure exceeds 16MPa, a high static differential pressure transmitter should be selected.

FAQ

Help Center

Smart transmitters work on the function of microprocessors for signal transmission.

Smart pressure transmitter consists of two parts: smart sensor and smart electronic board.

The intelligent sensor part includes: capacitive sensor, measuring diaphragm detection circuit, temperature sensor and temperature compensation circuit.

The part of the intelligent electronic board includes: a microcomputer controller and peripheral circuits. It completes the conversion of the pressure signal to 4-20mA dc.

Extended Reading: Digital Pressure Sensor-RS485

Depending on the type of pressure to be measured:

According to the working principle of the pressure transmitter:

Strain Gauge Pressure Transducers
Capacitance Pressure Transducers
Potentiometric Pressure Transducers
Resonant Wire Pressure Transducers

Extended reading: Silicon Pressure Sensor

Simply put, a differential pressure transmitter is a device that measures two opposing pressures in a pipe or vessel. Differential Pressure (DP) transmitters measure the difference between two pressures. They use a reference point called the low-side pressure and compare it to the high-side pressure. Ports in the instrument are marked high-side and low-side. The DP reading can be either negative or positive depending on whether the low-side or high-side is the larger value. A DP transmitter can be used as a gauge pressure transmitter if the low-side is left open to the atmosphere.

Extended reading: Featured Diaphragm Seal Pressure Transmitters

The most common and useful industrial pressure measuring instrument is the differential pressure transmitter. This equipment will sense the difference in pressure between two ports and produce an output signal with reference to a calibrated pressure range.

The differential pressure transmitter can be used in combination with other accessories and can be used to measure liquid level and flow.

Differential pressure transmitters and pressure transmitters have many similarities. It can be mixed and used most of the time. As long as it is within the range of the differential pressure transmitter, it can measure not only positive pressure but also negative pressure. When measuring positive pressure, the negative port is open to atmosphere, and when measuring negative pressure, the positive port is open to atmosphere.

Differential pressure transmitters can also measure flow, pipeline pressure difference, tank liquid level, bubble water level, dust, or medium that is easy to crystallize and viscous and fluidity is not good.

DP Level Transmitter for Tank Level Measurement

Posted on January 16, 2026 by KimGuo11

The DP level transmitter works on the principle that the hydrostatic pressure difference of a liquid is directly proportional to the liquid level height. It calculates the liquid level by measuring the pressure difference of the medium inside the container and outputs a standard electrical signal. The dual-flange capillary structure provides mechanical and thermal isolation, allowing it to handle complex corrosive and high-temperature media in various industrial processes and tank level monitoring applications.

Sino-Inst offers a variety of DP Level Transmitters for industrial pressure measurement. Connection with diaphragm seals. If you have any questions, please contact our sales engineers.

More DP Transmitters

Features

Exd II CT6 Gb/ Exia II CT6 Ga, suitable for direct use in hazardous areas and outdoors;
All sensor components are made of 316L stainless steel;
316 stainless steel diaphragm, convenient installation with movable flange;
6 diaphragm materials available: 316L diaphragm, HC276 diaphragm, tantalum diaphragm, 316L fully coated diaphragm, gold-plated diaphragm, PTFE diaphragm, etc., customizable;
High-precision configuration, optional 0.1%FS, 0.075%FS;
Extremely high anti-interference and stability;
275-point temperature, pressure, and current compensation;
LED LCD display, 0-100% percentage display, and real-time liquid level value display;
Output: 4-20mA + HART/RS485;
Nitrogen pressurized base, superior sealing performance, nitrogen pressurization prevents leakage.

Specifications of DP level transmitter

Measuring Medium:	Gases, Vapors, Liquids
Measuring Range	-100kPa…0~6kPa…7MPa
Accuracy:	±0.075%, ±0.1%, ±0.2% (including linearity, hysteresis, and repeatability from zero point)
Stability:	±0.2%/year
Power Supply:	10–36V DC (24V DC recommended)
Reference Accuracy for Range Adjustment:	If TD > 10 (TD = Maximum range / Adjustable range), then: ±(0.075 × TD)%
Ambient Temperature:	-40℃ ~ 85℃
Measuring Medium Temperature:	-40℃ ~ 400℃ (higher/lower temperatures can be customized)
Storage Temperature:	-40℃ ~ 85℃
Display:	LCD, OLED
Display Module Temperature:	-20℃ ~ 70℃ (LCD), -40℃ ~ 80℃ (OLED)
Measuring Diaphragm:	316L, Hastelloy C, Tantalum, Titanium, Nickel, Monel, Duplex Stainless Steel, PFA, Gold Plating
Process Connection:	Stainless steel 316L, 304
Filling Fluid:	Silicone oil, fluorinated oil, etc.
Transmitter Housing:	Aluminum alloy material, epoxy resin coating on the surface
Housing Seal:	Nitrile rubber
Nameplate:	Stainless steel 304
Enclosure Protection Rating:	IP67
Explosion Protection Rating:	Exd Ⅱ CT6 Gb, Exia Ⅱ CT6 Ga
Measuring Range Limits	Within the upper and lower limits of the range, it can be set arbitrarily, as long as the calibrated range ≥ the set range. It is recommended to choose a range with the lowest possible range ratio to optimize performance.
Influence of Mounting Position	Changes in installation position will cause zero point influence, which can be corrected by zero adjustment; there is no range influence.
Output	Two-wire 4-20mA, compliant with NAMUR NE43 standard, superimposed digital signal (Hart protocol)
Output Signal Limits	Imin (minimum): 3.9mA Imax (maximum) = 21.0mA
Alarm Current	Low alarm mode (minimum): 3.9mA High alarm mode (maximum): 21mA (user pre-settable)
Default Alarm Current Setting	High alarm mode
Fault Warning	If the sensor or circuit fails, the automatic diagnostic function automatically outputs 22.0mA
Response Time	Amplifier component damping constant is 0.1s; sensor time constant is 0.1–1.6s, depending on the range and range ratio. Additional adjustable time constant: 0–100s
Warm-up Time	<15s

There are 5 types of remote transmission devices for remote differential pressure transmitters:

Flat type
Thread mounting type
Flange mounting type
Extended Diaphragm Seal
Wet legs/Dry legs

SM3151LT liquid level pressure-differential pressure transmitter Download

Applications of DP level transmitters

The differential pressure liquid level transmitter can prevent the measured medium from directly contacting the sensor diaphragm of the transmitter. It is suitable for the following situations:

When the measured medium has a corrosive effect on the transmitter connector and sensitive components;
When the high temperature measured medium needs to be isolated from the transmitter;
When there are solid suspended solids or high viscosity in the measured medium, it is easy to block the transmitter connector and the pressure chamber;
When the measured medium is easily cured or crystallized by the pressure tube;
When changing the measured medium needs to be rinsed and not to be mixed;
Hygienic conditions must be maintained to prevent pollution. .
Changing the measured medium requires strict purification of the measuring head
Suspended liquid or high viscosity medium
Measurement of sealed pressure vessel.

DP level transmitter working principle

The differential pressure level transmitter is an instrument that uses the pressure generated by the liquid column to measure the height of the liquid level. When the liquid level changes, the pressure received by the diaphragm at the high-pressure side flange will change accordingly. The differential pressure value calculated by the transmitter will also change accordingly. There is a linear relationship between them.

Normally, the high-pressure side (H side) and the low-pressure side (L side) cannot be installed reversely. Generally, the H side is installed at the lower part of the equipment, and the L side is installed at the higher part of the equipment. Before installation, the flange surface of the equipment should be cleaned and the gasket should not be placed off-center to prevent the diaphragm from being punctured or deformed, causing distortion of the transmitter.

SMT 3151 Differential Pressure Level Measurement

Differential pressure transmitter level measurement calculation

When using a Differential pressure (DP) level transmitter to measure the liquid level as shown in the figure below.

The measured liquid density in the figure is ρ.
The working medium density in the capillary of the double flange differential pressure transmitter is ρ0.
The measuring range of the measured liquid level is H.
The center distance of the sampling tube of the measured liquid level is h.

It can be seen from the figure that the maximum measurement range of the liquid level △ P = P + — P- = H × ρ × g – h × ρ0 × g.

It can be seen from the formula that the dual-flange differential pressure transmitter should perform negative migration. The migration amount S is h × ρ0 × g. And the installation position of the double flange differential pressure transmitter has no effect on the migration amount and the measurement result.

The dual-flange differential pressure transmitter requires negative migration.

When the measured liquid level is 0, the pressure difference between the positive and negative measurement chambers of the remote differential pressure transmitter is the largest. The output current of the double flange differential pressure transmitter is 4mA.

As the measured liquid level rises, the pressure difference between the positive and negative measurement chambers of the transmitter gradually decreases.

When the measured liquid level rises to the highest Hmax. The pressure difference between the positive and negative measurement chambers of the transmitter is the smallest. The output current of the double flange differential pressure transmitter is 20mA.

DP level transmitter calibration

The differential pressure liquid level transmitter has been calibrated in the range, accuracy, linearity and other parameters according to customer requirements at the factory. And mark the range, accuracy, etc. on the nameplate of the differential pressure liquid level transmitter. As long as the density and other parameters of the measured medium meet the requirements of the nameplate, generally no adjustment is required.

If the customer needs to adjust the range or zero position, please adjust according to the following methods. Assuming that the range of the differential pressure liquid level transmitter is 0 ~ 10 meters:

Unscrew the protective cover of the differential pressure liquid level transmitter. It can be adjusted by connecting an external standard 24VDC power supply and ammeter (requires accuracy of 0.2% or above).
When there is no liquid in the differential pressure liquid level transmitter. Adjust the zero potentiometers. Make it output a current of 4mA.
Pressurize the differential pressure liquid level transmitter to full scale (10 meters). Adjust the full-scale resistor. Make it output a current of 20mA.
Repeat the above steps two or three times until the signal is normal.
Please input 25%, 50%, and 75% signals to check the error of the differential pressure liquid level transmitter.
For non-aqueous media. Differential pressure level transmitters are calibrated with water. It should be converted according to the pressure generated by the actual density of the medium. For example, when the medium density is 1.3, the 1.3m water level should be used to calibrate the 1m range.
After adjustment, tighten the protective cover.
The verification cycle of the differential pressure liquid level transmitter is once a year.
HART intelligent differential pressure liquid level transmitter of Sino-Inst instrument can be selected. It is convenient to adjust the range of the differential pressure liquid level transmitter.

Extended reading: How to calibrate HART pressure transmitters

More Featured DP Transmitters

**Smart Differential Pressure Transmitter**

Pressure Sensor | Designed for Shield boring machine-Earth compactor-Grouting machine

Posted on October 14, 2023 by KimGuo11

Shield boring machine Pressure Sensor The measuring end adopts a specially treated strong thick metal diaphragm. Adopting the principle of mechanical transmission, the hard sand and small rock particles in the measured medium sense the pressure through the isolation diaphragm without damaging the internal sensitive components. The pressure sensor has a compact structure, corrosion resistance, vibration resistance, hard sand impact resistance, and wide range temperature compensation. Suitable for pressure measurement of mud, wet soil and other media.

RFQ

Features of Shield boring machine Pressure Sensor

Using diaphragm isolation technology;
Integrated chip, wide voltage power supply;
High protection, compact structure and easy installation;
Cut-off frequency design, strong anti-interference ability, and lightning protection;
Current limiting, voltage limiting, reverse connection protection (current limiting output);
Resistant to vibration, frequent high-pressure impact, solid sand impact, and wear resistance;

Technical Parameters

Measuring medium:	Mud, wet soil, etc. (compatible with contact materials)
Pressure range:	0～0.6MPa (10, 16, 25, 40, 60, 100bar can be customized)
Pressure method:	Gauge
Accuracy level:	0.5%FS
Medium temperature:	-40～85℃
Connection time:	20ms
Stable performance:	±0.1% FS/year
Temperature compensation:	-10～70℃
Temperature drift:	±0.01%FS/℃ (within temperature compensation range) ±0.05%FS/℃ (outside temperature compensation range)
Protection level:	IP65
Durable performance:	1X10⁶ times (number of cycles from the lower limit of the measuring range to the upper limit of the measuring range)
Overall weight:	≈850g
Resolution:	Analog output 0.01%FS, digital output 0.05%FS
output signal:	4-20mA (two-wire system), 0-5/1-5/0-10VDC (three-wire system)
Supply voltage:	24VDC(10-30VDC)

Professional Applications

Specialized Pressure Transmitter for Heavy-Duty Machinery

When you’re dealing with machinery that faces rugged environments and intense pressure conditions, such as injection machines, tunnel boring machines (TBM), brick-making machines, and earth pressure machines, you need equipment that won’t buckle under the pressure – both literally and metaphorically. Enter our specialized pressure transmitter.

Injection Machines (Grouting Machines):

In the world of grouting machines or injection machines, consistency and precision are paramount. Given the intensity of the operations, the special thick metal diaphragm of our pressure transmitter stands out as an exemplary component. Not only does it efficiently sense the pressure of hard sand particles and small rock granules in the grout, but its unique mechanical transmission principle ensures that the sensitive internal elements remain undamaged. This guarantees precision and reduces maintenance downtimes.

Tunnel Boring Machines (Shield Machines or TBMs):

Tunnel construction is a challenging feat. With TBMs, where the machinery encounters diverse geological structures and varying pressure conditions, our pressure sensor plays a pivotal role. Its ability to withstand vibrations, corrosive environments, and the aggressive impact of hard sand granules ensures continuous, real-time pressure data. This translates to safer operations and optimal machine performance in various earth compositions.

Brick-making Machines:

Consistency is the hallmark of quality in brick-making. The compact structure and wide-ranging temperature compensation of our pressure transmitter ensure that it consistently delivers accurate pressure measurements. This aids in producing bricks of uniform quality and strength, regardless of the raw materials or environmental conditions.

Earth Pressure Machines:

Earth pressure machines handle varying types of soils, each with its own set of challenges. Our sensor’s robust design, capable of enduring the corrosive nature of some soils and the abrasive nature of others, proves invaluable. The quick and accurate pressure readings it provides enable operators to adjust machine parameters for optimal performance, ensuring efficient operations and reducing wear and tear on machinery.

SI-51 Miniature Pressure Sensor/Transducer

Posted on January 13, 2023 by KimGuo11

Miniature Pressure Sensor is also called Miniature Pressure Transducer. The miniature pressure sensor is a miniature solid-state silicon force sensor integrated with MEMS technology. One-piece miniature stainless steel package. Make it have excellent dynamic performance. Small size, streamlined, strong, compact shape structure.

RFQ Pressure Sensors

Features of Miniature Pressure Sensor

Product size Φ3, Φ5, M6, M8, M10. Can be specially designed according to specific working conditions;
Small size, streamlined appearance;
split structure. Optional standard voltage, current, digital signal output. Meet the requirements of various working conditions;
High dynamic frequency response, steep rising edge;
Wide measuring range. Any range between -100Kpa~0-10KPa…60MPa;

Specifications of SI-51 Miniature Pressure Sensor

Measuring range	-100KPa-0-10KPa…1MPa…60MPa
Measuring medium	Gases or liquids compatible with 316 stainless steel
Static accuracy	±0.1%FS ±0.25%FS ±0.5%FS
Dimensions	Φ3、Φ5、M6、M8、M10 (customizable)
Natural frequency	10KHz~1MHz
Product structure	Transmitter: split type
Signal output/power supply	4-20mA 0-5V 0-10V 1-5V	12-36VDC (Typical 24VDC)
	mV signal	Constant voltage source/constant current source
	Digital signal output RS485	5VDC/5-16VDC/24VDC
Operating temperature	-40～85℃
Compensation temperature	-10～60℃
Storage temperature	-40～100℃
Long term stability	Typical: ±0.1%FS/year Maximum: ±0.2%FS/year
Zero temperature drift	Typical: ±0.02%FS/℃ Maximum: ±0.05%FS/℃
Sensitivity temperature drift	Typical: ±0.02%FS/℃ Maximum: ±0.05%FS/℃
Overload capability	2 times full scale pressure or maximum 110MPa (take the minimum value)
Effective measurement life	﹥106 pressure cycles (P:10-90%FS)
Vibration resistance	20g （IEC 60068-2-6）
Impact resistance	20g，11mS
Resolution	Greater than 10-5 (usually limited acquisition and display equipment, theoretically infinitely small)
Load Resistance	≤(U-12)/0.02 Ω (current output) >100KΩ (voltage output)
Insulation resistance	200MΩ，100VDC
Electrical connections	Connector or direct cable 2m2m
Interface and housing material	304/316L stainless steel
Shell protection	IP65 (plug type) IP67 (cable type)
Explosion-proof	Ex iaⅡ CT5 (Intrinsically safe)
Seal ring	Fluorine Rubber
Sensor diaphragm	Stainless steel 316L
Product weight	The sensor is about 20-30 grams, and the transmitter is about 300 grams

Extended reading: NB-IoT Wireless Pressure Transmitter Networking Solution

Miniature Pressure Sensor/Transducer Applications

Water turbine and underwater weapon test
Fluid mechanics and hydraulic tests
Aircraft and Engine Tests
Aerodynamic studies
Biomedical Science
wind tunnel test
manufacturing
Equipment matching

More Featured Pressure Sensors & Transducers

**SI-390 Industrial Pressure Transmitter**

**SI-350 Sanitary Pressure Transmitter**

**SI-703 Flush diaphragm pressure sensor**

**Capacitive Gauge Pressure Transmitter**

Stainless Steel Level Sensor-Pressure Guided Submersible Level Transmitter

Posted on September 26, 2022 by KimGuo11

Stainless Steel Level Sensor-Pressure Guided Submersible Level Transmitter (gas pressure type. ) The sensor part and the signal processing circuit are inside the junction box. It is used for high temperature, corrosive liquid, sewage, etc. The gas in the gas collecting cylinder is injected into the liquid Contact with the medium. The pressure is transmitted to the sensor through the air pipe. The direct contact between the sensor and the measured medium is avoided. It is suitable for occasions such as high temperature and strong corrosiveness. It effectively solves the problem of high temperature corrosive liquid and sewage level measurement. It is especially suitable for the measurement of high temperature, corrosive liquid and sewage.

RFQ

Features of Stainless Steel Level Sensor

With high temperature resistance, all parts in contact with the medium are made of stainless steel;
Adopt sensor, circuit full protection design, stable and reliable performance;
The pressure-inducing structure ensures long product life and high precision;
High temperature resistance, anti-clogging, anti-corrosion, anti-condensation, anti-sewage;
Solid structure, no moving parts, maintenance-free after installation and use;
High-temperature liquid, sewage, etc. can be measured with high precision. Not affected by media foaming and deposition;
Easy installation, simple structure, economical and durable;
With power overload current limiting protection;
No material fatigue wear, insensitive to vibration and impact, and widely used;

Technical Parameters

1. Range:	0-100m (liquid level height/depth);
2. Output signal:	4-20mA (two-wire system), 0-20mA, 0-5V, 1-5V, RS485;
3. Load capacity:	800<ERR>
4.Insulation resistance:	greater than 2000M2 (100VDC);
5. Power supply:	24VDC (9~36DCV);
6. Accuracy class:	0.5%FS;
7. Long-term stability:	≤0.2%FS/year;
Temperature compensation:	0-80℃
9. Medium temperature:	0~400℃;
10. Ambient temperature:	normal temperature (0~60℃);
Ambient humidity:	≤90%RH
12. Protection class:	IP68
13. Main structural material:	Pressure tube material stainless steel 1Cr18Ni9Ti;The junction box is metal cast aluminum,Gas cylinder material: 304 stainless steel (medium 37mm*200mm);Airway material: 304 stainless steel (medium 4mm); (can be bent at will)304/316 stainless steel pipe optional

Extended reading: Non contact level measurement

Stainless Steel Level Sensor-Pressure Guided Submersible Level Transmitter Working Principle

The Pressure Guided Submersible Level Transmitter selects the pressure transmitter as the pressure measurement component. The liquid level pressure signal is collected by the gas collecting cylinder and transmitted to the pressure transmitter to convert the pressure signal into the liquid level signal output.

The relationship between pressure transmitter and liquid level is: P=0.0098ρH+Pc

where:
P pressure MPa;
ρ liquid density (g/cm3);
H liquid level depth (m);
Pc liquid surface pressure (normal pressure is 0)

Extended Reading: How many types of level transmitters are there?

Applications

Stainless Steel Level Sensor-Pressure Guided Submersible Level Transmitter is a good choice for diesel testing.
Its biggest advantage is simple installation and low cost. Professional commissioning and installation, setup, etc. are not required. Just put the stainless steel probe into the tank and the solid gauge head.

In the petrochemical industry, large oil tanks require a large range of high-precision liquid level sensors to monitor oil level. At present, there are many methods for measuring oil tank liquid levels:

Servo level sensor
Radar level sensor
Hydrostatic liquid level transmitter
Magnetostrictive liquid level sensor

Extended reading: Oil Level Measurement Solutions for the Oil & Gas Industry

Extended reading: Magnetostrictive Level Transmitter Working Principle

One of the more important factors to consider when choosing a submersible level meter in the wastewater treatment industry is chemical compatibility and material selection. From potable water to highly corrosive acids, submersible level
Meters are necessary to measure nearly countless liquid chemicals.

Long service life;
High-precision measurement is possible from water, oil to viscous paste;
A wide range of temperature compensation is not affected by the foaming, deposition, and electrical properties of the measured medium.

Extended Reading: Low Cost Float Level Sensor for Tank Liquid Volume Monitoring

If you want to measure the liquid level of high temperature media, in addition to the available magnetic flap, the economical choice is the submersible high temperature Stainless Steel Level Sensor.

Since the medium is high temperature, the measurement method should avoid direct contact between the probe sensor and the medium. The probe sensor can only withstand a temperature of 60 degrees. For this reason, the submersible high temperature Stainless Steel Level Sensor is structurally designed to have the probe sensor above the medium and not in contact with the medium at all. . So no matter how high the medium temperature is, the submersible high temperature Stainless Steel Level Sensor can be used freely.

When installing, just find a hole larger than Φ37mm in the liquid level tank and put it directly. The submersible high temperature Stainless Steel Level Sensor is also equipped with a display for ease of use. Reasonable prices will make every customer satisfied.

Extended reading: Flat Pressure Sensor for High Viscosity Fluids

More than just liquid level, monitor your tank volume more effectively!

Our liquid level sensors can output liquid level signals, such as 4-20mA signal, 0-10V signal, RS485 and so on.

However, the liquid level transmitter alone cannot calculate the liquid volume of tanks of different sizes. It’s too complicated. A separate recorder is required to calculate it.

Therefore, the digital display volume meter can collect, display and convert the liquid level of various regular and irregular tanks in the industrial field into the corresponding tank volume. It is suitable for monitoring, controlling and collecting various process parameters.

Read more about: Capacitive Level Measurement System

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Asked
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