Selection of Range

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 size of the measured pressure, but also the speed of the measured pressure change. The range must be reserved Enough room. When using a pressure gauge to measure stable pressure, the maximum working pressure should not exceed 2/3 of the range;
2. Use a pressure gauge to measure the pulsating pressure, and the maximum working pressure should not exceed 1/2 of the range;
3. When using a pressure gauge to measure high pressure, the maximum working pressure should not exceed 3/5 of the range. In order to ensure measurement accuracy, the minimum working pressure should not be lower than 1/3 of the range. According to this principle, after calculating a value based on the measured maximum pressure, select a measurement range slightly larger than the value from the pressure gauge product catalog.
4. The selection should be based on the working pressure of the boiler, and the limit value of the range scale should be 1.5 to 3.0 times the working pressure, preferably 2 times. In industrial boilers, the actual situation is that the actual working pressure of the boiler is always lower than the rated pressure on the nameplate. This is true for industrial steam boilers and hot water heating boilers. For example, a 4t/h steam boiler has a rated pressure of 1MPa. If the manufacturer is equipped with a pressure gauge at 1.5 times, it should be equipped with a 1.6MPa range pressure gauge. If the user needs the production process, the actual operation can meet the process requirements under the pressure of 0.5MPa. At this time, when the range is running, the pointer of the pressure gauge points to a position less than one-third of the range, and the angle of the pointer is very high. small. That is, the selected pressure gauge range is too large.
The same is true for hot water boilers. For example, the heating boiler has a rated pressure of 0.7 MPa, and the equipped pressure gauge should be 1 MPa or 1.6 MPa. If a 1 MPa pressure gauge is equipped, the pressure gauge may be overloaded during the hydraulic test, so the range is 1. 6MPa pressure gauge. In actual operation, as long as 0.2MPa can meet the heating requirements, the pointer of the pressure gauge points to the position of one-eighth of the range, and it is difficult to make people 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, the pressure gauge equipped by the boiler factory according to the rated pressure during the hydraulic test;
6. Equipped with a pressure gauge at twice the actual working pressure during daily operation. If the working pressure is 0.2MPa, a pressure gauge with a range of 0.4MPa is used. In this way, the pointer is in the middle of the dial, vertically upward. The seating pressure of the safety valve is also adjusted according to the working pressure, and the pressure gauge still has enough margin to cope with the overpressure indication.
Send feedback
History
Saved
Community