A shock resistant pressure gauge refers to a mechanical pointer type pressure gauge with a filled liquid inside the case, or a mechanical pointer (or rotary dial) type pressure gauge with a filled liquid and a damper inside the case. Widely used in mechanical, petroleum, chemical, metallurgical, mining, power and other departments, it measures the pressure of the medium that can withstand the pulsation, impact and sudden unloading of the medium in places with severe environmental vibration.
1. Selection of pressure gauge types
Firstly, clarify the functions that the selected pressure gauge needs to possess. Usually, pressure gauges filled with damping fluid are called shock resistant pressure gauges. For example, after adding damping fluid to an ammonia pressure gauge, it is called a shock resistant ammonia pressure gauge. After adding damping fluid to an electric contact pressure gauge, it is called a shock resistant electric contact pressure gauge. After adding damping fluid to a precision pressure gauge, it is called a shock resistant precision pressure gauge. So it is necessary to choose a suitable basic pressure gauge according to the actual situation.
2. Determination of measurement range
Be sure to be clear about the pressure range and pressure change status of the working medium. When selecting the measurement range of a shock resistant pressure gauge, reference can be made to the published "Design Specification for Selection of Automation Instruments" (HG/T 20507-2014). The selection of measuring range for pressure measuring instruments should meet the following requirements: 1) When measuring stable pressure, the working pressure should not exceed 2/3 of the upper limit of the measurement. 2) When measuring pulsating medium pressure (such as outlet pressure of pumps, compressors, fans, etc.), the normal operating pressure value should be within 1/3 to 1/2 of the instrument range.
3. Selection of accuracy level
Determine the accuracy of the instrument based on the allowable errors in the production process and the selected instrument range, calculate the allowable reference error of the instrument, and determine the accuracy level of the instrument in accordance with the national regulations. Generally speaking, the more precise the instrument selected, the more accurate and reliable the measurement results will be. But it cannot be assumed that the higher the accuracy of the selected instrument, the better, because more precise instruments are generally more expensive, and the operation and maintenance are more complicated.
4. Selection of damping fluid
Usually, there are two types of damping fluids: silicone oil and glycerin. The operating temperature range for silicone oil shock resistant pressure gauges is 5-55 ℃, while the operating temperature range for silicone oil shock resistant pressure gauges is -25 ℃ -55 ℃. When selecting damping fluid, it is necessary to consider the ambient temperature. In autumn and winter, low temperature has a significant impact on the viscosity of damping fluid, especially in northern regions where appropriate damping fluid should be carefully selected.