The gate valve usually is at the off-position, the water pump starts when the gate valve opens slowly, when water pumpengine off, the gate valve shuts down slowly first.
闸阀平时是处于关闭状态,水泵启动时闸阀慢慢打开,水泵停机时,闸阀先慢慢关闭。
3
He thereby transformed an inefficient pump of limited use into a steam engine of a thousand uses.