Air driven pumps and components therefor

Abstract

An air driven double diaphragm pump including two opposed pump chambers with an air motor having air chambers therebetween. The pump chambers and air chambers form pumping cavities divided by diaphragms. Each pump chamber includes an inlet ball valve and outlet ball valve. An inlet manifold is positioned below the pump chambers and an outlet manifold above. Tie-rods extend both across the pump from one pump chamber to the other with nuts to place the assembly in compression. Tie-rods also extend from the outlet manifold through the pump chambers, to the inlet manifold and to feet mounted therebelow. Two plates, one to either side of the air motor extend to grooves in the inlet and outlet manifold and also extend to grooves in the pump chambers so as to close of the side of the pump structure. With the plates, an outlet manifold is provided from which air may be exhausted remotely. The ball valves include small diametrical clearance and a limitation on lift for added performance. The ball valves also include seats which are sealed with the components of the pump through the use of O-rings and surfaces polished to 10R.sub.A. Belleville washers relieve thermal stresses on the tie-rods. Integrally molded diaphragms include an annular sheet about a hub. A semi-circular corrugation about the periphery provides for attachment to the pump while a cylindrical flange mates with a boss on the respective pump chamber. A stud is molded as an insert into the diaphragm. The pullout failure rate of the stud is empirically established by appropriate sizes of circumferential ribs and hub thickness to be higher than the rupture rate for the annular sheet.