How to Use the Diaphragm Pressure Gauge?

Diaphragm pressure consists of a diaphragm isolator and a general-purpose pressure gauge to form a system of diaphragm gauges.

1. Application of diaphragm pressure gauge

Diaphragm pressure gauges are mainly used to measure the pressure of fluid media in the production process of petrochemical, soda making, chemical fiber, dyeing, pharmaceutical, food, sanitation systems and soda making industries.

Diaphragm pressure gauges are suitable for measuring the pressure of corrosive, high viscosity, easy to crystallize, easy to solidify, high temperature liquid, gas or granular solid media, and must avoid the measurement medium directly entering the diaphragm pressure gauge and prevent sediment accumulation and easy Cleaning occasions. Diaphragm pressure gauges are mainly used in petroleum, chemical, chemical fiber, dyeing, pharmaceutical, alkali food and other industrial sectors.

Due to different uses, diaphragm pressure gauges have various structures and connection forms, such as open flanges, I-shaped flanges, angled flanges, hose connections, clamp connections, etc.

2. What problems should be paid attention to when using the diaphragm pressure gauge?

Since the diaphragm pressure gauge system is filled with sealing fluid as the pressure transmission medium, the temperature influence of the diaphragm pressure gauge is related to the linear expansion coefficient of the sealing liquid, the stiffness of the diaphragm and the temperature of the pressurized part. When the temperature of the instrument deviates from the specified value (such as 20±5°C), the impact on the low-range pressure gauge is obvious.

Generally, the temperature error of the pressure part is specified to be no more than 1.0%/℃, so the temperature influence value of the diaphragm pressure gauge is the sum of the temperature influence value of the ordinary pressure gauge and the temperature influence value of the pressure part of the diaphragm isolator, this should be paid attention to in use.

Attention should also be paid to the influence of liquid level and static pressure on diaphragm pressure gauges during use. Diaphragm pressure gauges with flexible connecting pipes will produce liquid column differences and affect measurement results when the pressure-receiving part of the diaphragm is not at the same height as the installation position of ordinary pressure gauges, more attention should be paid when measuring.

The main purpose of the diaphragm pressure gauge is to prevent corrosion, so it can be guaranteed by selecting the appropriate diaphragm material and the materials of the diaphragm, flange and sealing gasket that are in contact with the measurement medium.

Commonly used diaphragm materials are: OCr17Nil2Mo2 (316); OCr17Nil4Mo2 (316L); Monel (Cu30Ni70); Hastelloy (H276C); Tantalum (Ta) and fluoroplastic (F4).

Flange materials are: stainless steel 0Cr18Ni9 (304), OCr17Nil2Mo2 (316); stainless steel lined with fluorine plastic (316+F4).

Gasket materials are: nitrile rubber; fluororubber; silicone rubber and fluoroplastics. The appropriate sealing liquid should be selected according to different purposes to ensure the reliability and safety of the diaphragm pressure gauge.