GB1080584A - Improvements in or relating to fluid spraying apparatus - Google Patents

Abstract

1,080,584. Polishing. JOHN HAWLEY & CO. (WALSALL) Ltd. March 28, 1966 [March 30, 1965], No. 13323/65. Heading B3D. [Also Divisions B2 and F2] Fluid spraying apparatus comprises a spray head and a fluid control valve controlling the admission of the fluid to the spray head, the fluid control valve comprising a body having an inlet for the fluid and an outlet for the fluid communicating with the spray head, a valve seat within the body and a valve member cooperating with the valve seat to control the flow of the fluid from the outlet, the valve member being in the form of a flexible diaphragm of elastomeric material, there being a valve actuating member operable to deflect the diaphragm from a position in which it is clear of the valve seat into a position in which it makes sealing engagement with the valve seat. Polishing compound comprising abrasive particles in suspension in a liquid is supplied, e.g. by a pump, through a valve 18 to a spray head 11, 14; compressed air is supplied to the spray head through an inlet 13. A fine dispersion of compound is formed by the atomizing effect of the air and droplets are carried on to the working face of a polishing wheel with sufficient force to penetrate the air stream surrounding the wheel. The valve 18 has a body part 19 the wall of which has an opening 24. A transverse web 26 has its upper surface 27 machined concave to form a seat for a diaphragm 30. The diaphragm 30 is coupled by a member 32 to the rod 33 of a piston 41 working in a cylinder 35 formed in a housing part 20 of the valve 18. The end face 45 of the coupling member 32 is convex of such curvature that when the coupling member is in closure position the peripheral edge region 46 of the coupling member presses the diaphragm into engagement with the upper edge of the opening 24, the central region 48 of the coupling member pressing the diaphragm into engagement with the seat on the web 26. The valve 18 is normally held closed by springs 49, 50. Operation may be controlled by a 3-way solenoid operated valve (55, Fig. 4) actuated by electrical impulses, e.g. from a timing device (56). When the valve (55) is in ON position, compressed air from line (64) passes (i) through a pressure regulator (61) to the air inlet 13 of the spray head, and (ii) into the cylinder 35 below the piston 41; the pressure is such that, together with the internal stresses in the diaphragm 30, it exactly counterbalances the force of the springs 49, 50 so that the polishing compound lifts the diaphragm 30 off its seat and flows to the spray head. When the valve (55) is in OFF position, compressed air from line (64) is stopped in the valve (55), and the cylinder 35 is connected to exhaust so that the springs 49, 50 close the valve 18. Instead of the 3-way valve (55), a 4-way valve (67, Fig. 5) with ports (70, 71b) blocked off may be used. In a modification (Fig. 2) the valve closing springs 49, 50 are omitted; a branch line (76, Fig. 4) from the air supply line (64) communicates with the cylinder 35 above the piston 41. In a further modification (Fig. 3) the valve closing springs 49, 50 are again omitted; there is no air connection to the cylinder 35 below the piston 41; the cylinder 35 above the piston 41 is connected by a line (77, Fig. 5) to the valve (67). When valve (67) is in OFF position air is supplied through line (77), closing the valve 18. When valve (67) is in ON position, air is supplied to the inlet 13 of the spray head and the line (77) is connected to exhaust whereby the liquid polishing compound opens the valve 18 and flows to the spray head. In the above modifications, polishing compound must not be supplied under pressure to the valve 18 if compressed air is not being supplied to the control system.