God, can you explain to me in detail why?
Check valve in the valve in front. To prevent water from flowing back.
Pump outlet, check valve, gate valve.Gate valve plays a regulatory role, is the main pipe. Such a sequence can ensure that the water flow during power failure does not cause damage to the gate valve.
The exit of the general pump is the first soft connection (shock absorber), followed by the check valve, and then the partition valve (such as butterfly valve, gate valve, cut-off valve, etc.), this is not the final answer.The question is interesting, and no corresponding information has been found in the relevant standards. We have also discussed the related issues, but differences of opinion is relatively large, the advantages of 1, first installed check valve installed after the valve or butterfly valve, check valve, can be protected, especially in a parallel pump, when the pump does not start, another pump starts when the impact force is gate valve or butterfly valve bear, disadvantages: gate valve or check valve who will protect? There have been a case of butterfly valve is broken. 2, first installed gate valve or butterfly valve installed after the check valve, advantages: can protect the butterfly valve or gate valve, the impact on the check valve to bear. Disadvantages: check valve who will protect, check valve by pressure difference switch, if the high pressure high pressure pipe, pump, if the flow is not stable, so check valve will repeatedly switch, will affect the check valve life. Personal opinion: check valve, check valve performance now have changed, many are using the slow closing check valve, so the impact force is two aspects to bear, because exports are not fully open the valve or butterfly valve, so you can put in check after the gate valve or butterfly valve valve. If not the slow closing check valve installed in the valve or the best after the butterfly.
