Characteristics and selection of diaphragm pressure gauges

Time: 2024-10-10
Equipment Configuration:diaphragm pressure gauges

Diaphragm pressure gauges are composed of various general-purpose pressure instruments and diaphragm isolators of different structures to form a closed system filled with sealing liquid.

Project Overview

Structural principle:

Diaphragm pressure gauges are composed of various general-purpose pressure instruments and diaphragm isolators of different structures to form a closed system filled with sealing liquid. When the pressure of the measured medium acts on the diaphragm, the diaphragm deforms and compresses the sealing fluid in the closed system. Due to the inherent properties of the sealing fluid, the elastic element in the pressure instrument produces corresponding elastic deformation-displacement, and the pressure value is displayed by the indicating device. When the stiffness of the diaphragm is small enough, the pressure indicated by the pressure instrument is close to the pressure value of the measured medium.

Main technical indicators:

○Temperature characteristics of the diaphragm meter

Since the system of the diaphragm meter is filled with sealing liquid as the medium for pressure transmission, the diaphragm The temperature influence of the table is related to the expansion coefficient of the sealing liquid, the stiffness of the diaphragm and the temperature of the pressure-bearing part. The impact is particularly obvious for low-range pressure instruments. Generally, the temperature error of the pressure-receiving part is not greater than 1.0%/℃, so the temperature influence of the diaphragm meter is generally the sum of the temperature influence of the general pressure instrument and the temperature influence of the pressure-receiving part of the diaphragm isolator.

○The liquid level difference of the diaphragm gauge

Especially for the diaphragm gauge with a flexible connecting pipe, since the pressure-receiving part of the diaphragm and the installation position of the universal pressure gauge are not on the same level, there will be The influence of liquid level difference △P. More care should be taken when measuring accurately.

○Corrosion resistance of the diaphragm meter

The corrosion resistance of the diaphragm meter can be ensured by appropriately selecting the materials of the diaphragm, flange and sealing gasket of the parts in contact with the measurement medium.

Diaphragm material: 0Cr17Ni12Mo2 (316); Monel alloy (Cu30Ni70); Hastelloy (H276C); Tantalum (Ta) and fluoroplastic (F4).

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

Sealing gasket material: nitrile rubber; fluorine rubber; silicone rubber and fluorine plastic.

○Selection of diaphragm fluid

To ensure the reliability and safety of the diaphragm meter, appropriate sealing fluid should be selected according to different uses.

Diaphragm device flange dimensions:

1. Open flanges

can be manufactured according to the flange standard dimensions provided or specified by the user

2. I-shaped raised face flange [code MG] upper limit of measuring range: ≤4MPa

3. Threaded joint type [ML] upper limit of measuring range: ≤60MPa

4. Bolt type diaphragm isolator [code MZ] Measuring range: 1~25MPa Diaphragm and diaphragm seat material: 0Cr17Ni12Mo2 (316)

5. Clamp type diaphragm isolator [code MC]

6. Nut type diaphragm isolator [code MN]

7. Rectangular flange type diaphragm isolator [code MH]

Related Cases

The magnetic inductive flowmeter industry, these are successful cases with comparable and reference value.

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