The stainless steel flange diaphragm pressure gauge consists of two main parts: a diaphragm isolation device and a pressure gauge. This diaphragm pressure gauge is widely used in industries such as petroleum, chemical, pharmaceutical, food, paper, etc. to measure the pressure of liquid media with strong corrosiveness, high viscosity, easy crystallization, and containing solid particles.

Structure principle of diaphragm pressure gauge

The stainless steel flange diaphragm pressure gauge consists of various universal pressure instruments and diaphragm isolators of different structures, forming a closed system filled with sealing fluid. When the pressure of the measured medium acts on the diaphragm, the diaphragm deforms and compresses the sealing liquid in the closed system. Due to the inherent properties of the sealing fluid, the elastic elements in the pressure instrument undergo corresponding elastic deformation and displacement, and the pressure value is displayed by the indicator device. When the stiffness of the diaphragm is small enough, the pressure indicated by the pressure gauge is close to the pressure value of the measured medium.

Selection Table for Diaphragm Pressure Gauge

Accuracy: ± 1.6%, ± 2.5%.

Diaphragm material: OCr18Ni12MO2 (316), Hastelloy C (H276c), Monel alloy (Cu30Ni70), Tantalum alloy (Ta), Fluoroplastic (F4).

Isolator material: acid resistant stainless steel, molybdenum containing stainless steel, fluoroplastic.

Sealing gasket material: Fluoroplastic.

Sealing fluid: silicone oil, vegetable oil

Execution standard: JB/T8624-97

Main technical indicators of diaphragm pressure gauge

Temperature characteristics of diaphragm pressure gauge

Due to the sealing liquid filling the system of the diaphragm pressure gauge as a pressure transmission and medium, the temperature effect of the diaphragm gauge is related to the expansion coefficient of the sealing liquid, the stiffness of the diaphragm, and the temperature of the compressed part. The impact on low range pressure instruments is particularly evident. The temperature error of the general pressure part is not greater than 0.1%/℃, so the temperature effect of the diaphragm gauge is generally the sum of the temperature effect of the general pressure instrument and the temperature effect of the pressure part of the diaphragm isolator.

● Level difference of diaphragm pressure gauge

Especially for diaphragm gauges with flexible connecting tubes, due to the fact that the diaphragm pressure receiving part is not installed on the same horizontal plane as the universal pressure gauge, there will be a liquid level difference and an impact quantity △ P. This is especially important when measuring accurately.

Corrosion resistance of diaphragm pressure gauge

The diaphragm pressure gauge and corrosion resistance can be ensured by selecting appropriate materials for the diaphragm, flange, and sealing gasket in contact with the measuring medium.

Flange material: Stainless steel 0Cr17Ni12Mo2 (316); Stainless steel lined with fluoroplastic (316+F4).

Sealing gasket material: rubber; Fluororubber; Silicone rubber and fluoroplastics.

● Selection of diaphragm fluid

To ensure the reliability and safety of diaphragm pressure gauges, suitable sealing liquids should be selected according to different applications.