| 摘要 |
Apparatus and method of improving the performance of a pump for pumping fireproofing material and the like viscous materials is disclosed wherein the pump is the type which includes a compression chamber (44) having an inlet (48) and an outlet (50). A piston cylinder (19) is disposed in fluid communication with the compression chamber and, a piston assembly (A, D, G) is carried in the piston cylinder driven in reciprocating suction and compression strokes. The piston assembly includes an extended piston (B,E) carried on a push rod (18) having a piston face (42, 61) terminating adjacent an inlet ball limit pin (52), having a reduced pin length of 5/16 inch, at the end of the compression stroke. The piston is further provided in a form having downwardly angled contoured surface (38,60) extending from a cylindrical surface (40, 62) to the piston face wherein the contoured surface is formed in a manner that clearance exists between the piston and an inlet ball valve (48a) at the end of the compression stroke so that the full extent of the piston may be had into the compression chamber. The piston assembly further includes a piston cup (26) constructed from a polymeric material having a cylindrical base (26a) with an outer diameter less than an inner diameter of the piston cylinder (19). A cylindrical wall (26) extends from the cylindrical base having an outer diameter greater than the outer diameter of the cylindrical base for sealingly engaging the piston cylinder wall.
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