Hits:Updated:2019-11-27 15:11:23【Print】
1. In order to ensure that the elastic elements 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 measured pressure, but also the speed of the pressure change. 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. 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. 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. It should be selected according to the working pressure of the boiler. 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 working pressure of the boiler in actual operation is always lower than the rated pressure on the nameplate. This is true of industrial steam boilers and hot water heating boilers. For example, a 4t / h steam boiler has a rated pressure of 1 MPa. If the manufacturer is equipped with a pressure gauge at 1.5 times, it should be equipped with a 1.6 MPa range pressure gauge. If the user can meet the process requirements under the actual operation of 0.5MPa pressure due to the production process requirements, at this time running the range, the pointer of the pressure gauge refers to a position less than one-third of the range, and the angle of the pointer is very small. That is, the range of the selected pressure gauge is too large.
The same is true for hot water boilers. For example, the rated pressure of a heating boiler is 0.7 MPa, and a pressure gauge equipped with it should be 1 MPa or 1.6 MPa. 1.6MPa pressure gauge. In actual operation, as long as 0.2 MPa can meet the heating requirements, the pointer of the pressure gauge points to one-eighth of the range, it is difficult to convince people of 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 gauges provided by the boiler plant according to the rated pressure during the hydraulic test;
6. Equip with a pressure gauge at twice the actual working pressure in 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, pointing up vertically. The seating 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.
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