This disclosure relates to a highly durable positive displacement pump
capable of dry-priming and pumping of a liquid containing abrasive
non-soluble material. The pump assembly comprises an internally
pressurized diaphragm assembly secured to a pump bowl and a pump bowl
tube. A suction inlet and discharge outlet are located at opposite ends of
the pump bowl tube, the inlet and outlet are each configured to receive a
valve that limits flow of the liquid to a single direction. The internally
pressurized diaphragm assembly comprises an upper diaphragm positioned
atop a lower diaphragm wherein a cavity is formed between the diaphragms
that is pressurized thereby reducing fatigue failure inducing stresses.
Reciprocating axial movement of the internally pressurized diaphragm
assembly, produced by a drive means, suctions the liquid in through the
suction inlet and then discharges the liquid through the discharge outlet.
