Working mechanism of hand pump

 Working of hand water pump

 It works on the principle that liquid flows from higher pressure region to lower pressure region. 

 1 st step: UPSTROKE During this step the handle goes down but piston goes up. Vacuum is created below piston valve so low pressure is created there hence water from ground pushes the foot valve up and comes in cylinder. 

2 nd step: DOWNSTROKE During this step the handle goes up but piston goes down. Water is compressed by piston so pressure increases and water pushes the piston valve rising above it. 

3 rd step: UPSTROKE Finally with upstroke water is pushed out from the outlet nozzle.