why a positive displacement pump is called a self priming

Centrifugal pump can not pull the liquid but it posh the liquid.
priming means filling the pump casing with liquid and their why removing air from the casing intially before starting the centrifugal pump which cannot create low pressure by rotating air, 8f filled inside the casing and hence centrifugal pump cannot handle air but positive displacement pump have the ability to handle liquid with a certain volumein entrained air.Thus they can pull the liquid and don’t required any priming and hence  called self priming pump as the pumps operation itself will create vacuum book by displacing air Or liquid Which ever is there inside the pump casing


Please enter your comment!
Please enter your name here