Pressure gauges are common measuring instruments and ar […]
Pressure gauges are common measuring instruments and are widely used in various production fields. How to choose the pressure gauge should be based on the use requirements, on the premise of meeting the technological requirements, comprehensive consideration should be based on the principle of economy and practicality, so as to reasonably select the accuracy level, range, type and model.
One, the determination of the accuracy level of the pressure gauge
According to the principle of precision pressure gauge, the accuracy grades are 0.1, 0.16, 0.25, 0.4 grades; the accuracy grades of general pressure gauges are 1.0, 1.6, 2.5, and 4.0 grades.
The method of selecting the accuracy level of the pressure gauge: The accuracy level should be determined according to the requirements of the production process, economy and practicality, testing methods, etc., according to the allowable error required by the minimum value of the measured pressure. According to the pressure measurement requirements of the process and production process, and according to economic principles, reasonable selection of pressure gauge types, pressure gauge models, pressure gauge ranges, pressure gauge accuracy grades, etc. should be selected from the following three conveniences when selecting pressure gauges. .
(1) Selection of pressure gauge type: The selection of pressure gauge type should mainly be considered from two aspects that can meet the requirements of process production and price. For example, is it necessary to indicate on-site or remote transmission, automatic recording or alarm; whether the physical and chemical properties of the measured medium (such as corrosiveness, temperature, viscosity, degree of dirt, flammability, etc.) are suitable for measuring pressure gauges There are special requirements; whether the on-site environmental conditions (such as high temperature, electromagnetic field, vibration, etc. on-site installation conditions) have special requirements for the type of pressure gauge, etc.
(2) Determination of the measuring range of the pressure gauge: The measuring range of the pressure gauge refers to the range from the lower limit to the upper limit of the scale of the pressure gauge, which indicates that the pressure gauge can measure the measured parameter according to the specified accuracy. For example, when measuring pressure, in order to avoid the overload of the sensing element of the spring tube pressure gauge from being broken, the upper limit of the pressure gauge should be higher than the maximum pressure value possible in process production. In addition, in order to make the pressure gauge work reliably, it is necessary to consider leaving enough room when selecting the pressure gauge. According to regulations, when the measured pressure is relatively stable, its maximum value should not exceed 2/3 of the range of the pressure gauge; when measuring high pressure and fluctuating pressure, the maximum working pressure should not exceed 3/5 of the range . How to connect the three wires of the potentiometer remote pressure gauge
3) Selection of the accuracy grade of the pressure gauge: The accuracy grade of the pressure gauge is determined according to the maximum absolute error allowed in the process production. Generally speaking, the higher the accuracy level of the pressure gauge, the more expensive it is, and the higher the operation and maintenance requirements are. Therefore, the pressure gauge with lower accuracy, simple structure, cheap and durable should be selected as far as possible under the premise of meeting the requirements.