Check valve selection 1) check valve is generally suitable for cleaning media, should not be used for containing solid particles and a larger viscosity medium. 2) For aetv One-way valve below DN50mm, butterfly check valves, vertical lifting check valves and diaphragm check valves are recommended; for low and medium pressures with DN greater than 200mm and less than 1200mm Check valve, should choose no wear ball valve; For DN greater than 50mm, less than 2000mm low pressure check valve, should choose butterfly check valve and diaphragm check valve. 3) Diaphragm check valve is suitable for easy to produce water hammer on the pipeline, the diaphragm can be well eliminated when the media counter-current water hammer, but by the temperature and pressure limits, generally used in low pressure at room temperature pipe. 4) For the requirements of water hammer stroke when the impact is relatively small or no water hit the pipe, should use the slow closing swing check valve and slow closing butterfly check valve.