Air operated pump and motor

In an air operated pump and motor unit for transferring liquid from beneath a liquid surface to a point above the liquid surface, wherein said pump and motor unit comprise a rotor head assembly, an impeller head assembly, and a spacer tube unit disposed between said assemblies and affixed and its upper and lower ends respectively to said rotor and impeller assemblies, and wherein said impeller head assembly includes means defining a pumping chamber with at least one liquid inlet and at least one liquid outlet, a liquid discharge line extending from said liquid chamber outlet to a liquid discharge outlet, and a liquid impeller assembly disposed within said pumping chamber and including a plurality of blades each carried by an impeller hub, said rotor head assembly comprises a rotor housing having an inner end face, a radially inwardly directed cylindrical sidewall portion and a cover assembly closing off the top of said rotor housing and having an axially inner surface spaced from and in facing relation to said inner end face of said housing, said sidewall and end facer thereby defining an air chamber for said rotor element, said rotor housing also including means defining at least one high pressure inlet in said sidewall portion and a rotor element disposed within said chamber and mounted for rotation about a drive shaft axis, said rotor element having a hub affixed at its center to a drive shaft extending from said rotor hub and being joined to said impeller hub, the improvement comprising said rotor element also having a blade carrier unit of generally annular form and having a plurality of radially extending blade units disposed on the side of said annular blade carrier facing said housing inner end face, and a spider unit extending between and joining said rotor hub and said blade carrier and also providing plurality of passages for axial airflow therethrough, said rotor hub and said spider lying adjacent said housing inner end face, with said carrier having portions lying adjacent said cover assembly axially inner surface, said rotor assembly thereby subdividing said rotor chamber into upstream and downstream chambers communicating with each other through said passages in said spider, with said rotor housing also including means defining at least one high pressure inlet in said sidewall portion, said cover assembly including an inner cover unit and an outer cover unit spaced closing axially apart from each other to define therebetween a radially extending diffuser passage, said inner cover unit further including a plurality of passages extending axially between said downstream chamber and said diffuser passage, whereby air passes in use from said air inlet to said upstream chamber, and then to said downstream chamber through said axial spider passages, and thereafter through said cover passages to and through said diffuser passages.