Diaphragm Seal Pressure Transmitters

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.

Diaphragm Seal Pressure Transmitters

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

Flush diaphragm pressure sensor
Sanitary Pressure Transmitter
Diaphragm Seal Pressure Transmitter
Remote Diaphragm Seal Pressure Transmitter
Flange Mounted Differential Pressure Transmitter
Extended Diaphragm Seal DP Level Transmitter
Remote Seal Differential Pressure Transmitter
Differential pressure(DP) level 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:

  1. Separation of the measuring instrument from the process medium
  2. Transfer of the pressure to the measuring instrument

You may like: Diaphragm pressure gauge

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.

You may like: How does a pressure transmitter work?

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.

Read more about: What is industrial pressure transmitter?

When to use diaphragm seal ?

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

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

Difference between bourdon tube and diaphragm pressure gauge:


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

Related Blogs

What is Static Water Pressure?

What Is Static Water Pressure? Definition of Static Water Pressure: Static Water Pressure refers to the pressure on water when it is stationary or moving in a straight line at…

Static Pressure/Hydrostatic Pressure Transmitter

The Hydrostatic Pressure Transmitter measures the hydrostatic pressure exerted by a hydrostatic head. Use these hydrostatic pressure transmitters to measure the liquid level in storage tanks, processing vessels, collection tanks,…

The Myth of Ceramic Pressure Sensor

What is a ceramic pressure sensor? Ceramic pressure sensors are sensor diaphragms made of ceramic alumina (Al2O3). Ceramic is a material with high elasticity, corrosion resistance, wear resistance, impact, and…

What does intrinsically safe mean?

Intrinsically safe type is an explosion-proof type of electrical equipment. When purchasing electrical equipment, do you often hear about intrinsic safety? For example, when ordering pressure transmitters or flow meters…

What does SCADA stands for?

What does SCADA stand for? SCADA is the abbreviation of Supervisory Control And Data Acquisition. Namely data acquisition and monitoring control system. SCADA system is also called monitoring configuration software,…

How to convert a 4-20mA to 0-10V /1-5V signal?

4-20mA to 0-10v voltage, this is I/V conversion. That is current-voltage conversion, usually used for long-distance signal transmission in the industry. How to convert a 4-20mA to 0-10V /1-5V signal?…

What is a pressure sensor?

What is a pressure sensor? A pressure sensor is a device that senses a pressure signal and converts the pressure signal into a usable output electrical signal according to certain…

What is a PID controller?

What is a PID controller? A PID controller is an instrument used in industrial control applications to regulate temperature, flow, pressure, speed, and other process variables. PID is the abbreviation…

High Frequency Dynamic Pressure Sensor

Dynamic pressure sensor, the transmitter is a high frequency sensor. Sino-Inst offers a variety of  Dynamic Pressure Sensors for pressure measurement. If you have any questions, please contact our sales…

Differential Pressure Transmitter Installation Guide

Differential pressure transmitter installation guide helps you solve the installation problem of DP Transmitters. Sino-Inst offers a variety of  differential pressure transmitters for pressure/level/flow measurement. If you have any questions,…

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
This entry was posted in Pressure, Diaphragm Seal by KimGuo11. Bookmark the permalink.

About 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.