In the process of using a high vacuum butterfly valve, it will be often affected by temperature. And the following is the simple analysis:
1. Influenced by high temperature
After the relaxation of flange, bolts and gasket, the prestress of the bolts and the carrying capacity of flange connection will de decreased and all these can lead to the leakage problem. When temperature increases, especially under the condition of PN1.6 and 2.5 MPa, you should pay attention to the leakage problem in flange connection process.
2. Influenced by low temperature
If the temperature is 29 below, then the toughness and impact resistance of some material will be decreased obviously. In this case, the pressure is not allowed to be larger than the corresponding pressure in the same temperature.
3. Influenced by thermal expansion of the media
In some cases, the sealing design of double sealing seat can withstand the differential pressure simultaneously from adjacent pipes which acted on the two directions of valve bonnet. When the valve bonnet is full of medium, then the temperature will be increased and the pressure of the valve
bonnet will be rose, too. For example, when using the isolation valve to test the high temperature system by cold water pressure, if you do not fully open the isolation valve to discharge the medium, then the stranded medium may be heated when the system is running. User should ask the manufacturers to provide the installation measures and operating specification to ensure the pressure of a high vacuum butterfly valve
will not exceed the allowable pressure in the standard corresponding temperature.