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Diaphragm Pressure Gauge

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  • Accuracy: (add to instrument accuracy) ± 0.5% 
  • Working Temperature: -45-+150℃ 
  • Diaphragm material: Hastelloy B, Hastelloy C, Tantalum,Titanium, Monel 316L PTEE coated Wetted material:321, 304, 316L(or+PTFE) 
  • Connection: Thread M20*1.5,1/2”NPT other on request 
  • Filling liquid: As different media, optional fluorocarbon oil, -60-+120℃, Food oil, -20-+200℃
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Diaphragm pressure gauges introduction

Diaphragm pressure gauge, also known as a membrane pressure gauge, is a device that utilizes the deflection of a flexible thin membrane called the ‘diaphragm’ to measure the pressure of the fluid in a system. The membrane isolates the inner-working components of the pressure gauge from the media, preventing any contamination. This property makes the diaphragm pressure gauge suitable to use with corrosive or contaminated liquid or gaseous media.

This pressure gauge is utilized for low-pressure measurement and is used in applications such as measuring atmospheric pressure or monitoring pressure in a gas canister.


Diaphragm pressure gauges feature

  • Gauge Material: The housing material of the gauge and especially the parts coming in contact with the media should be chemically compatible. Since the diaphragm pressure gauge is mostly used with corrosive as well as highly viscous media, stainless steel is the preferred choice of material. Other common housing material includes aluminum and copper. See our Chemical Compatibility Chart for more detail on material compatibility.

  • Pressure ranges: A diaphragm pressure gauge is an ideal choice for low-pressure measurement applications. For general applications, the pressure gauge must be able to withstand the maximum and minimum pressure ranges. The maximum pressure should not be greater than 75% of the full-scale range and 65% for the pulsating range.

  • Temperature range: The temperature requirement of the application should be within the temperature limits that the pressure gauge can withstand. Typical diaphragm pressure gauges can withstand the temperature range of -20°C to 100°C (-4°F to 212°F), but look at the specifications.

  • Diaphragm size: In the selection of diaphragm size, the general rule of thumb is, lower the pressure, the larger the diaphragm size, and vice versa. During pressure measurement, the diaphragm should be big enough to displace a sufficient amount of fluid volume. For low-pressure measurement, larger volume displacement is required which requires a larger diaphragm to create sufficient displacement. Similarly, for high-pressure measurement, low volume displacement is usually enough, which can be fulfilled by a smaller diaphragm.

  • Fluid media: Unlike other vicious media, crystallizing and contaminated media may clog the narrow pressure entry point or even at the pressure chamber. To avoid such risk, a diaphragm pressure gauge with an open connection flange can be used to eliminate clog problems.

  • Pressure unit: The pressure measure unit for the diaphragm pressure gauge is bar or psi. The pressure may usually range from -1 to 400 bar.


Diaphragm pressure gauges specification

Diaphragm pressure gauges have a simple working mechanism,  It consists of a thin circular membrane of a metal sheet called a diaphragm which can be either flat or corrugated. When the pressure is applied, the deflection in the diaphragm should be linear. A flat diaphragm can ensure linearity only for small deflections. So, for industrial application, a corrugated diaphragm is preferred. The diaphragm can either be welded or clamped between the pair of flanges. The welded diaphragm is usually preferred in sanitary applications to prevent any potential for leakage.


The diaphragm separates the environment within the gauge where one side can be exposed to the atmosphere and the other side can be enclosed. This media separation ensures that the internal gauge components are protected when working with corrosive or viscous fluids.


As the pressure is applied to the system via the inlet , it causes the diaphragm to deflect. This deflection is translated into the movement of the pointer via the link  and gears, ultimately displaying the accurate measurement of the change in the pressure. The pressure is usually specified in bar or psi (pound per square) and there are different accuracy classes to indicate the maximum deviation. Read our technical article to learn more about pressure gauges and how they work. 

diaphragm pressure gauge

-Manuals

Diaphragm pressure gauge

-Data sheet


Diaphragm pressure gauges application

Diaphragm pressure gauges have been successfully used by numerous industries for both absolute and differential pressure measurement applications. The ability to separate media and avoid contamination makes it suitable to use in applications where purity is desired. It is also suitable for industries that require dealing with corrosive fluids. Some industries with applicability for diaphragm pressure gauge may include:


  • Food and beverage

  • Pharmaceutical

  • Petrochemical

  • Mining

Pressure gauges are used in a wide variety of applications besides the above. There are pressure gauges which are intended for use in vacuums, on air compressors, in hydraulic applications, and even for swimming pool filters. 


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