Features of different types check valve.
check valve(back pressure valve, swing valve, one-way valve): a valve that closes by fluid pressure to prevent return flow (Also called nonreturn valve),A check valve is a mechanical valve that only permits water flow in one direction. There must install check valve where don't allow fluid flow back such as compressor or pump outlet.

For low pressure medium and nominal diameter <DN50mm, select Butterfly swing check valve, vertical lift check valve or diaphragm check valve.
If 1200mm>DN>200mm, select butterfly check valve or diaphragm.
If require pipe small water hammer or no water hammer, better select slow-close type swing check valve and low-close butterfly check valve.
 

1.   H71H, H71Y, H71F wafer connection lift (elevated) check valve

Short structure, light weight, with spring loaded, quick close, can reduce water hammer.