How to choose a suitable diaphragm pressure gauge.
Pressure gauges are mainly divided into two types, one is mechanical, the other is electronic. Now let me talk about mechanical pressure gauges. Mechanical pressure gauges are divided into Bourdon tube pressure gauges, diaphragm pressure gauges, differential pressure gauges, diaphragm pressure gauges and so on.
In our real work, we generally need to confirm the following parameters:
Dial diameter.
The dial diameter is the diameter of the shell of the pressure gauge that we can default to. The most commonly used diameters are 50mm, 63mm, 100mm and 150mm (I am listed by European standards. China and some other countries will be a little different).
Second, shell material.
Generally speaking, the shell of the pressure gauge will be made of ABS (engineering plastic), carbon steel, 304stainless steel and copper alloy. We have to choose the shell material of the pressure gauge according to the specific environment.
ABS and 304stainless steel are usually used.
Third, connection mode.
The connection mode of the pressure gauge can be divided into axial (back connection) and radial (bottom connection), but in reality, customers can choose some options according to the specific situation, if it is panel installation, axial can choose front flange or rear with fixed bracket, radial can choose front flange or rear fixed edge, and so on.
Diaphragm pressure gauge.
Fourth, measuring medium.
Generally speaking, there are only two (standard) liquid contact materials for pressure gauges, namely, copper alloy and 304 stainless steel. If the medium you measure is not suitable for these two kinds or corrosion, then you can choose the pressure gauge to be used together with the chemical seal (the function of the chemical seal is to effectively prevent the measuring medium from coming into contact with the measuring element without affecting the pressure measurement of the pressure measuring element, so as to protect the measuring element.
Also play a role in prolonging the life of the measuring element).
5. Liquid filling.
In some environments where mechanical vibration is relatively large, we find that many pressure gauges are filled with liquids. In fact, the main function of these liquids is to increase resistance and effectively prevent the continuous vibration of the hands of the pressure gauges, so that we can accurately read the pressure values.
It is commonly used in the vicinity of the pump or in the environment with severe vibration.
VI. Medium temperature.
Generally speaking, the measuring medium temperature of copper alloy measuring elements is + 80 degrees and that of stainless steel is + 200 degrees; but if the pressure gauge you choose is a liquid-filled and shockproof pressure gauge, the medium temperature at this time can only reach + 100 degrees; if the temperature is too high, but to be shockproof, the method we adopt is condensation bending.
7. Measuring range.
Because the pressure gauge is through the deformation of the measuring element, through the magnifying mechanism to drive the rotation of the pointer, so as to display the pressure value, we should also pay attention to when selecting the measuring range, the general measured pressure is the range of the pressure gauge 3GUB4 or 2Universe 3 is ideal, if the selection is large, the change of the pointer is small, the pressure value read out is not accurate, if the selection is small, the pressure gauge will be damaged due to overload.
Connection size.
Now, due to the different thread standards in different countries, the main ones commonly used are M (Metric), G (, Imperial), NPT (, American), R (, Japan and South Korea, etc.) and so on.
