Diaphragm seals, mechanical pointer gauges and pressure transmitters for liquid pressure measurement

Abstract

The invention discloses a diaphragm sealing device for measuring liquid pressure, a mechanical finger pressure gauge and a pressure transmitter. The diaphragm sealing device for measuring the liquid pressure comprises a capillary pipe filled with filling liquid, wherein a diaphragm slice is arranged at one end port of the capillary pipe for closing the end port; the capillary pipe is fixed on a liquid storage tank through a flange short pipe; one end, provided with the diaphragm slice, of the capillary pipe penetrates deep into liquid in the liquid storage tank; the other end of the capillary pipe is connected with a measuring instrument; the inner diameter of the capillary pipe is 0.1-0.5 mm, and the outer diameter of the capillary pipe is 13-18 mm. The diaphragm sealing device for measuring the liquid pressure is directly in contact with a measured medium, so that a medium dead area formed by the flange short pipe of a measuring hole of the storage tank and a temperature gradient area on the wall of the tank are avoided, and the measuring values can be accurately obtained. Furthermore, as the filling liquid has low heat expansion coefficient, the measuring system error is relatively small along with the temperature variation.

Description

technical field [0001] The invention relates to a diaphragm sealing device for liquid pressure measurement, in particular to a diaphragm sealing device for pressure measurement suitable for sublimation and crystallization liquids, a mechanical pointer pressure gauge and a pressure transmitter. Background technique [0002] Diaphragm pressure gauge is a commonly used mechanical pressure measuring instrument, which uses a diaphragm as a pressure sensor, and the diaphragm is circular with ring-shaped corrugations. The diaphragm is usually sandwiched between two flanges, and one side is in contact with the medium. Under the action of the medium pressure, the diaphragm will produce elastic deformation. The deformation reflects the pressure of the medium and is indicated by the pointer. [0003] However, the above-mentioned diaphragm pressure gauge will be affected by many factors when working, such as temperature. Since the diaphragm for sensing pressure is located in the medium ...

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Problems solved by technology

[0003] However, the above-mentioned diaphragm pressure gauge will be affected by many factors when working, such as temperature. Since the diaphragm for sensing pressure is located in the medium "dead zone" of the flange short tube, the medium in contact with the diaphragm will be affected by the flange tube. The resulting temperature change produces a change in density, and thus generates static pressure, thereby changing the temperature characteristics of the pressure gauge

In addition, when the liquid to be measured is a liquid that is easy to sublimate and crystallize, it is easy to block the short flange tube, making the pressure gauge unable to work normally

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