Wika pressure gauge use precautions introduction

In order to ensure that the elastic element of the pressure gauge can work reliably within the safe range of elastic deformation, the selection of the pressure gauge range should not only be based on the magnitude of the measured pressure, but also the speed of the measured pressure change, and the range must be sufficient. room.
       1. The accuracy level of the wika pressure gauge reflects the accuracy of the indication value and the actual value in the comparison between the inspection table and the precision meter. It is equal to the percentage of the absolute value of the large basic error and the upper limit of the measurement, which is determined by the magnitude of the error generated in the calibration.
       2. China's general industrial pressure gauges are divided into four accuracy grades, which are in line with the allowable error of the pressure gauges in the JJG52-1999 "spring tube type general pressure gauge, pressure vacuum gauge and vacuum gauge" verification procedures. The four accuracy levels are: Level 1, Level 1.6, Level 2.5, Level 4. The allowable error (calculated as a percentage of the upper measurement limit) is ±1%, ±1.6%, ±2.5%, ±4%, respectively.
       3. China's new digital pressure gauge verification procedures were promulgated and implemented in 2005, in line with JJG875-2005 “Digital Pressure Gauge Calibration Regulations”. The pressure accuracy is specified as ±0.01%, ±0.02%, ±0.05%, ±0.1%, ±0.2%, ±0.5%, ±1.0%, ±1.6%, respectively.
       4. Reasonable selection of the accuracy level of the wika pressure gauge should be based on the requirements of production process, economical utility, testing methods, etc., and the accuracy level should be selected according to the allowable error required by the measured pressure* small value.
       Choose the method of wika pressure gauge range:
       High pressure gauge stainless steel wika pressure gauge
       1. In order to ensure that the elastic element of the pressure gauge can work reliably within the safe range of elastic deformation, the selection of the pressure gauge range should not only be based on the magnitude of the measured pressure, but also the speed of the measured pressure change. There is plenty of room. When using a pressure gauge to measure stable pressure, * large working pressure should not exceed 2/3 of the range;
       2. Use a pressure gauge to measure the pulsation pressure. * The large working pressure should not exceed 1/2 of the range;
       3, when using the wika pressure gauge to measure high pressure, * large working pressure should not exceed 3/5 of the range. In order to ensure measurement accuracy, * small working pressure should not be less than 1/3 of the range. According to this principle, after calculating a value according to the measured maximum pressure, a measurement range slightly larger than the value is selected from the pressure gauge product catalog.
       4, should be selected according to the working pressure of the boiler, the limit value of the range scale should be 1.5 ~ 3.0 times the working pressure, * good is 2 times. In industrial boilers, the actual situation is that the working pressure of the boiler is always lower than the rated pressure on the nameplate, both industrial steam boilers and hot water heating boilers. For example, a 4t/h steam boiler with a rated pressure of 1 MPa, if the manufacturer is equipped with a pressure gauge 1.5 times, should be equipped with a 1.6 MPa range pressure gauge. If the user needs to run the process under the pressure of 0.5MPa due to the production process, the process can meet the process requirements. At this time, the running range, the pointer of the pressure gauge refers to the position less than one third of the range, and the angle of the pointer is very small. The selected pressure gauge has a too large range.
       The same is true for hot water boilers. For example, the rated pressure of heating boilers is 0.7 MPa, and the pressure gauge should be 1 MPa or 1.6 MPa. If equipped with a pressure gauge of 1 MPa, it is afraid to overload the pressure gauge during the hydraulic pressure test, so the range is 1.6. MPa pressure gauge. In actual operation, as long as 0.2MPa can meet the heating requirements, the pointer of the pressure gauge refers to one-eighth of the range, which makes it difficult to believe the accuracy and sensitivity of the pressure gauge.
       5. In order to solve the above problems, two kinds of pressure gauges should be used, that is, when the hydraulic pressure test is used, a pressure gauge equipped by the boiler factory according to the rated pressure is used;
       6. Install the wika pressure gauge at 2 times the actual working pressure during daily operation. If the working pressure is 0.2MPa, it is equipped with a pressure gauge of 0.4MPa range. This way the pointer is in the middle of the dial and is vertically up. The seat valve pressure of the safety valve is also adjusted according to the working pressure, and the pressure gauge still has sufficient margin to cope with the overpressure indication.