High pressure source for viscous liquids, especially those containing suspended abrasive particles

摘要

1, 098, 070. Reciprocating pumps. H.G. FISCHER & CO. Inc. Oct. 8, 1965 [Oct.9, 1964], No.42709/65. Heading F1A. Pumping apparatus for liquids with suspended solid particles, e.g. for supplying paint to spray guns, comprises one or more pistons 78, Fig. 3 each formed with an annular groove for carrying a quantity of the solid particles to form a seal between the piston and its associated cylinder wall. The pistons control inlet ports 76 in the cylinders 72 to draw liquid from a casing in which the pumps are mounted, Figs. 1 and 12 (not shown). The pumps deliver via ball valves 87 to a spray gun through a line incorporating an adjustable pressure relief valve, which discharges into the casing, Fig. 6 (not shown), a filter and a pressure gauge. The pumps are driven by an electric motor 12 or I. C. engine through an eccentric 21, a strap 36 and a connecting rod 38 with a yoke coupled by link 54 to piston rod 60. A transverse beam 125 on rod 60 carries paddles for stirring the liquid in the casing. The pump pistons and cylinders may be of tungsten carbide, nitrided steel or ceramic-clad metal with surfaces finished by lapping or honing to a smoothness of about 10 micro-inches. The pump assembly may be mounted in a reservoir on a trolley, Fig. 1, or on wall brackets with a suction line leading to a separate reservoir, Fig. 12 (not shown).