On/off water hammer effect eliminating device for water pump

The invention discloses an on/off water hammer effect eliminating device for a water pump, and relates to the field of high-lift water supply and drainage. The end B of a water pump water drainage main pipe is connected with the water pump; the end A of the water pump water drainage main pipe is connected with a water supply and drainage system outlet; a water drainage main pipe check valve is mounted on the water pump water drainage main pipe; a bypass pipe is connected downstream the water drainage main pipe check valve; an overhaul gate valve I is mounted on the bypass pipe; a pressure-relief branch pipe is connected to the middle of the bypass pipe; a pressure-relief branch pipe check valve and a pressure-relief valve are mounted on the pressure-relief branch pipe in sequence; the end C of the pressure-relief branch pipe is connected with a floor drain, a sump pit or other drainage measures; an overhaul gate valve II is mounted on the bypass pipe and behind the pressure-relief branch pipe; the tail end of