What are the requirements for installing check valves at the inlet and outlet of a compressor?
Thread Content
I saw a PID diagram from abroad; check valves are installed at both the inlet and outlet of the compressor. I’m not quite sure what the purpose of these is. I’d like to ask everyone for their insights.
A check valve is a one-way flow valve designed to prevent gas from flowing back during shutdowns or abnormal stops, which could otherwise cause equipment damage. It is also required by the process specifications.
Check valves are installed at both the inlet and outlet of the compressor; I’m not quite sure what the purpose of that is
Exports are easy to understand; could you send a picture for me to take a look?
Generally, the total pressure of a compressor is greater than 3 kilograms of pressure; this is to prevent gas from flowing back and damaging the equipment components in the event of a shutdown or emergency stop
The issues mentioned on the first floor are a bit too general; it would be better to share a simplified version of the PID diagram you saw so that everyone can take a look before discussing it. This approach will make things more intuitive and targeted. Here are a few situations for the original poster’s reference: 1. A liquid ring compressor uses a liquid as the working fluid, usually water. When the compressor stops operating, the outlet pressure is high, which causes the working fluid to flow back to the inlet. If no check valve is installed at the inlet, the working fluid can easily flow back into the system; therefore, it is essential to install a check valve at the inlet ； 2. A check valve at the outlet should also be installed, to prevent backflow of gas from the high-pressure side from affecting the liquid ring pump during shutdown. Moreover, since the outlet pressure of conventional liquid ring compressors (single-stage, single-acting) is not high, it is generally around 0. 1–0. 2 MPa G; it’s not necessary to use it, as it will not have any adverse effect on the liquid ring compressor. However, for double-acting and two-stage types, the high pressure can generally reach around 1 MPa or even higher; it is advisable to install a check valve at the outlet as well. 3. For multi-stage reciprocating compressors where there are other process units connected between the stages, check valves should be installed at the corresponding outlets to prevent backflow of the medium during shutdown. The same is true for centrifugal compressors.