GB1498224A - Apparatus for accumulating liquid pulses and for developing an elevated liquid pressure for subsequent release to the exterior - Google Patents

Abstract

1498224 Reciprocating pumps GRACO Inc 5 June 1975 [29 Aug 1974] 24270/75 Heading F1A [Also in Divisions B2 and F1] A paint sprayer comprises a motor 10 operated by a trigger 16, a piston 25 reciprocated by the motor through gears 11 and 12 and eccentric shaft 18, a paint container 30 from which the piston draws paint through suction tube 31, a first chamber 32 into which the pulses of paint are admitted by a non-return ball-valve, and a second chamber 33 connected to the first chamber and being formed in a resilient first member 28 against which rests a second member 50 having an outlet passage therein closable by a valve (55), Fig. 2 (not shown), so that pulses of paint from the container build up the hydraulic pressure in the second chamber forcing the second member forward against the resilient member and when the pressure is sufficient the resilient member deforms to lift the second member from the valve and allow a pulsed high-pressure flow through the outlet passage. In modifications, Figs. 5A and 5B (not shown), the movement of the second member may be additionally or alternatively facilitated by spring washers being positioned adjacent or in place of the resilient member. In use the resilient member is reciprocated at 2,000 to 3,000 strokes per minute by a <SP>1</SP>/ 3 horsepower electric motor operating at 12,000 r.p.m. and the valve (55) will either remain open or, open and close at the same rate as the piston reciprocates to produce a high-pressure pulsed spray which appear continuous. With an outlet having an area of 0À013 sq. in. a peak hydraulic pressure of 2,000 to 2,500 p.s.i. is produced using water-base latex paint. A drainage passage 38 is provided from the cylinder in which the piston reciprocates.