A shock-resistant pressure gauge refers to a mechanical pointer pressure gauge filled with liquid in the case, or a mechanical pointer (or rotary dial) pressure gauge with a damper filled in the case. It is widely used in machinery, petroleum, chemical industry, metallurgy, mining, electric power and other departments to measure the medium pressure in places with severe environmental vibrations that can withstand the pulsation, impact and sudden unloading of the medium.
1. Selection of pressure gauge type
First, clarify the functions that the selected pressure gauge needs to have. Usually, the pressure gauge after filling with damping fluid is called a shock-resistant pressure gauge. For example, an ammonia pressure gauge after adding damping fluid becomes a seismic ammonia pressure gauge; an electric contact pressure gauge after adding damping fluid is called a seismic-resistant electric contact pressure gauge; and a precision pressure gauge after adding damping fluid is called a seismic-resistant precision pressure gauge. Therefore, an appropriate basic pressure gauge must be selected according to the actual situation.
2. Determination of measuring range
Be sure to know the pressure range of the working medium and its pressure change state. When selecting the measurement range of a seismic pressure gauge, you can refer to the "Automation Instrument Selection and Design Specifications" (HG/T 20507-2014) issued by the Ministry of Industry and Information Technology. The selection of the measuring range of the pressure measuring instrument should meet the following requirements: 1) When measuring stable pressure, the maximum working pressure should not exceed 2/3 of the upper measurement limit. 2) When measuring pulsating medium pressure (such as outlet pressure of pumps, compressors and fans), the normal operating pressure value should be between 1/3 and 1/2 of the instrument range.
3. Selection of accuracy level
According to the maximum absolute error allowed by process production and the selected instrument range, the maximum reference error allowed by the instrument is calculated, and the accuracy of the instrument is determined within the accuracy level specified by the state. Generally speaking, the more precise the instrument selected, the more accurate and reliable the measurement results will be. However, it cannot be considered that the higher the accuracy of the selected instrument, the better, because the more precise the instrument is, the more expensive it is and the more troublesome it is to operate and maintain.
4. Selection of damping fluid
Usually, there are two types of damping fluids: silicone oil and glycerin. The operating environment temperature of silicone oil shock-resistant pressure gauge is 5~55℃, and the operating environment temperature of silicone oil shock-resistant pressure gauge is -25~55℃. When selecting damping fluid, you need to consider the ambient temperature. In autumn and winter, the low temperature has a greater impact on the viscosity of the damping fluid. Especially in northern areas, you should carefully select the appropriate damping fluid.
