US3476052A - High pressure pump for sprayer - Google Patents

Description

4, 1969 J. WAGNER HIGH PRESSURE PUMP FOR SPRAYER 2 Sheets-Sheet 1 Filed July 9, 1968 FIG I FIG 2 Q 1 gm/J Ev.

INVENTOR JOSEF WAGNER BY JMWJrM ATTORNEY Nov. 4, 1969 J. WAGNER HIGH PRESSURE PUMP FOR SPRAYER Filed July 9, 1968 2 Sheets-Sheet 2 FIG 7 INVENTOR JOSEF WAGNER 191L214, ATTORNEY FIG 5 United States Patent 3,476,052 HIGH PRESSURE PUMP FOR SPRAYER Josef Wagner, 507 Postfach, 799 Friedrichshafen 12, Germany Continuation-impart of application Ser. No. 647,139,

June 19, 1967. This application July 9, 1968, Ser.

Int. Cl. F04!) 49/00, 1 9/ 22; F04d 15/02 US. Cl. 103-41 Claims ABSTRACT OF THE DISCLOSURE A high pressure pump for a sprayer having a positively driven piston operating a suction valve, said operation forming a pressure chamber, an outlet from said pressure chamber, a regulating valve operatively connected to said pressure chamber, a suction bore inlet, a throttle valve operatively connected to said suction bore inlet, and a leakoff conduit in communication with said suction bore inlet.

would also build up as a crust at points which were not,

easily accessible for cleaning.

Parent application Ser. No. 647,139, corrected some of the problems found in prior art pumps. It has been found through empirical observation that a pump piston is better served when positively driven in two directions in place of being driven in one direction against the tension of a spring, and the spring react to move the piston in an opposite direction.

In this manner, partially dried or very high viscosity paint cannot hinder the reciprocating motion of the piston. In the parent application the by-pass valve is on the pressure side of the piston. Constant re-circulation of paint leads to the heating up of the paint. To overcome this disadvantage, a throttle valve is placed on the suction side of the piston.

Accordingly, it is an object of the present invention to provide a construction wherein the pump piston is positively driven in two directions.

Another object of the present invention is to provide a piston pump with a by-pass valve on the suction side of the piston.

Still another object of the present invention is to provide means, whereby, the by-pass valve does not close completely, so that a very small amount of liquid will constantly re-circulate within the pump. In this manner, the pump piston is prevented from operating in a completely dry condition.

Other objects of the present invention will become apparent in part and be pointed out in part in the following specification and claims.

Referring to the drawings in which similar characters of reference refer to like parts:

FIGURE 1 is a front elevational view of the pump portion of a sprayer;

FIGURE 2 is a left side elevational view of FIGURE 1;

FIGURE 3 is a bottom plan view of FIGURE 1;

FIGURE 4 is a fragmentary perspective view, partly in section of the pump housing;

FIGURE 5 is a horizontal cross-sectional view, taken on line 55 of FIGURE 2;

FIGURE 6 is a horizontal cross-sectional view, taken on line 6-6 of FIGURE 3;

FIGURE 7 is a horizontal cross-sectional view, taken on line 77 of FIGURE 3, in a plane at right angles to the plane of FIGURE 6;

FIGURE 8 is a view, similar to FIGURE 6, showing the piston in vacuum or fluid intake position.

In proceeding with this invention, reference is made to all of the figures of the drawing.

With special reference to FIGURES 4, 5, 6, 7 and 8, a block of material constitutes a pump housing 11 provided with a piston bore 12. Piston bore 12 may be provided with a tungsten carbide bushing 26 and fastened therein, by means of a drive fit, and a tungsten carbide piston cyllnder 27 having an inlet orifice 28, a beveled valve seat 29, and also fastened in piston bore 12 by means of a drive fit. When bushing 26 and cylinder 27 are provided as liners in p1st0n bore 12, a duct 30 is provided between bushing 26 and cylinder 27. A nap ring 3 may be provided in the wall of piston bore 12 as a stop for cylinder 27 A suction inlet bore 21, an inlet chamber 20, a leak-01f conduit 18 and a return conduit 23 are provided in pump housing 11. Inlet chamber 20 connects suction inlet bore 21 with inlet orifice 28. Return conduit 23 connects leak-off conduit 18 with inlet chamber 20, so that a fluid flow path is provided between duct 30 and inlet orifice 28, through inlet chamber 20. Inlet orifice 28 connects piston bore 12 with inlet chamber 20 and suction inlet bore 21.

A piston 31 provided with a cam yoke, C shaped, follower 32 is slidably mounted in bushing 26 and piston cylinder 27.

A support cap 33 provided with a neck 34, shoulder 35 (FIGURE 6) and an axial bore-36 is fastened to block one end of piston bore 12. A suction valve stem 37 provided with valve head 38 having a beveled face is slidably mounted in axial bore 36 by means of stem 37. A coil spring 39 surrounds neck 34 and is interposed between shoulder 35 and head 38. Coil spring 39 resiliently urges beveled face against valve seat 29. A pressure chamber P is formed in piston bore 12 between valve seat 29 and shoulder 35. A pressure regulating conduit 16 provides an outlet from pressure chamber P. A by-pass conduit 17 provides an outlet from pressure regulating conduit 16. A high pressure outlet (FIGURES 4 and 5) provides a fluid flow path from pressure chamber P to a fitting 81, rotatively mounted in pump housing 11, to which a spray gun (not shown) may be attached.

A threaded bore 40 having a base 41 is provided in pump housing 11. A bushing 42 is rotatively mounted in threaded bore 40. A throttle valve, generally indicated by reference numeral 43, consists of a flat parallel sided wing 44, a tit 45 extending from wing 44 on one end, a stem 46 projecting from the opposite end of Wing 44, and a collar 48. Tit 45 rotatively engages a bore in pump housing 11 provided for that purpose. Stern 46 is rotatively mounted in bushing 42. Friction washers 47, 47A are placed on opposite sides of collar 48, so that the end of bushing 42 frictionally engages washers 47, 47A and collar 46 with base 41.

A. pressure regulating valve, generally indicated by reference numeral 50, (see FIGURE 5) comprises a bushing 51 provided with a needle valve seat 52 and fastened in pump housing 11 at the juncture of pressure regulating conduit 16 and pressure chamber P.

A cover guard 60 is fastened to pump housing 11 by means of a bushing 61 rotatively mounted in threads 62 provided in pump housing 11. Bushing 61 has a shoulder 63 which engages cover guard 60 so it fastens guard 60 in position.

A sleeve 65 provided with an axial orifice 66 and an enlarged head 67 is rotatively connected to bushing 61 by means of threads 68. A knob 69 may be fastened to head 67 by means of a drive fit.

The pressure regulating by-pass valve 50, also comprises a flat parallel sided wing 70 and a shank 71 forming a shoulder 72. Wing 70 is rotatively mounted in axial orifice 66 with a coil spring 73 located in axial orifice 66 and interposed between shoulder 72 and the base 74 of orifice 66. A needle valve 75 is fastened in the end of wing 70 and is adapted to engage needle valve seat 52 under the resilient force of coil spring 73.

A pressure gauge fitting connection 13 is provided in pump housing 11, with a bypass conduit 14 connecting pressure chamber P, with fitting connection 13. A pressure gauge 15 may be attached to fitting connection 13.

A fitting 24 having a conduit 25 is rotatively mounted in pump housing 11, with conduit 25 forming a continuation of suction bore 21, so as to be attached to a supply of fluid.

In operation, a cam (not shown), rotates, so as to reciprocate cam follower 32. This would be an up and down motion, the direction of arrows A in FIGURE 7. Piston 31 is therefore, positively driven, in reciprocating motion.

Reference is made to FIGURE 6. Arrow B indicates the direction (upward) of piston 31 in the fluid intake stroke. FIGURE 8 shows the piston 31 at the top of the intake stroke, and about to move into the (downward) fluid exhaust stroke.

This FIGURE 8 shows a vacuum chamber V formed between the end of piston 31 and the top of suction valve head 38. The vacuum causes fluid to flow through suction inlet bore 21 passed wing 44 of throttle valve 43 into inlet chamber and through inlet orfice 28 into vacuum chamber V. As the piston moves (downward) in the fluid exhaust stroke, valve head 38 moves away from valve seat 29 against the tension of spring 39 and the fluid, now under pressure created by the downstroke of the piston, flows into pressure chamber P. On the downstroke, the bottom of piston 31 forces the fluid in three directions, simultaneously. First, the fluid will act against valve head 38 so as to move the beveled face of valve head 38 away from valve seat 29. The fluid will flow from pressure chamber P through high pressure outlet 80 to a tool such as a sprayer.

Secondly the fluid will flow through the clearance provided around the outside diameter of piston 31 and the inside of piston cylinder 27 and into duct 30 Where the fluid flow will continue into leak-ofl? conduit 18, return conduit 23 and into inlet chamber 20, so as to mix with the fluid supply in inlet chamber 20.

Thirdly, the fluid will tend to back out through inlet orifice 28. This orifice 28 is of a size to be too small in comparison to the volume of vacuum chamber V to make the flow through orifice 28, inconsequential. There will also be some back pressure in inlet chamber 20.

In the present invention let it be supposed that a paint spray gun is attached to fitting 81 and that the nozzle chosen for the spray gun has a very small orifice. The stroke of piston 31 is constant. The volume of paint pumped is therefore constant. Therefore, back pressure developes in high presure outlet 80 because the volume of paint pumped from pressure chamber P exceeds the volume of paint which can be discharged from the noz- Zle. To take care of this contingency, applicant places a manually operated throttle valve 43, in the suction bore 21. This throttle valve 43 controls the volume of fluid permitted to pass through suction inlet bore 21 and is regulated in accordance with the volume of discharge choosen, by way of the spray gun nozzle. This throttle control 43 controls the volume of fluid passing through the pump and controls the volume of fluid within the pump and thereby reduce the hazard of recirculating excess fluid (paint) which heats up when recirculated.

Paints with hammer finishes which become damaged if recirculated, may be pumped by the instant structure.

If the spray gun is shut-oif or if the volume of paint is not fully discharged from pressure chamber P, the needle valve 75 of regulating by-pass valve 50 will be actuated, so as to bleed the excess volume of fluid from pressure chamber P.

Regulating valve 50 is also an adjustment for the volume of fluid which will pass from pressure chamber P to high pressure outlet 80. The rotation of knob 69 increases or decreases the compression on spring 73. Needle valve 75 is normally engaged with needle valve seat 52 under the degree of pressure exerted upon needle valve 75. When the fluid pressure in pressure chamber P exceeds the force of spring 73, needle valve 75 will move away from valve seat 52 to thereby permit the fluid in pressure chamber P to by-pass needle valve 75 and flow into by-pass conduit 17 and back into the fluid container.

It will therefore, be understood, that the fluid to be pumped will determine if the regulating by-pass valve 50 is a needed structure in combination with throttle valve 43 or if either the regulating by-pass valve 50 or the throttle valve 43, will be used separately or jointly.

Having shown and described a preferred embodiment of the present invention by way of example, it should be realized that structural changes could be made and other examples given without departing from either the spirit or scope of this invention.

What I claim is:

1. A high pressure pump for a sprayer consisting of a pump housing having a piston bore, a piston cylinder provided with an inlet orifice, means fastening said piston cylinder in said piston bore, a bushing, means fastening said bushing in said piston bore in spaced relation to said piston cylinder to provide a duct therebetween, a suction inlet bore, an inlet chamber providing a flow path between said inlet orifice and said suction bore, a leak-off conduit in communication with said duct, a return conduit between said leak-ofi conduit and said inlet chamber, a suction valve, means fastening said suction valve in said piston bore, a pressure chamber located in said piston bore with said suction valve controlling the flow of fluid into said pressure chamber, a high pressure outlet in communication with said pressure chamber, a piston slidably mounted in said piston cylinder and in said bushing, movement of said piston away from said suction valve creates a vacuum chamber in said piston bore, whereby fluid flows from said suction inlet bore through said inlet chamber and inlet orifice into said vacuum chamber, and reciprocation of said piston actuates said suction valve, to force fluid from said vacuum chamber past said suction valve and into said pressure chamber to said high pressure outlet, a throttle valve, and means fastening said throttle valve in said pump housing and in the flow path of said suction inlet bore, thereby to control the volume of fluid flowing into said vacuum chamber.

2. A high pressure pump for a sprayer, as claimed in claim 1, in which said pump housing is provided with a pressure regulating conduit in communication with said pressure chamber, a by-pass conduit in communication with said pressure regulating conduit, providing a fluid flow path from said pressure regulating conduit through said pump housing, and a regulating valve, means fastening said regulating valve in said pressure regulating conduit to thereby control the fluid pressure in said pressure regulating conduit to thereby control the fluid pressure in said pressure chamber.

3. A high pressure pump for a sprayer as claimed in claim 1, in which said piston cylinder and said bushing are fabricated from tungsten carbide material.

4. A high pressure pump for a sprayer consisting of a pump housing having a piston bore, a suction inlet bore, means providing a fluid flow path between said suction inlet bore and said piston bore, including an inlet orlfice, a throttle valve, means fastening said throttle valve in said pump housing in the flow path of said suction inlet bore, a pressure chamber in said piston bore, a high pressure outlet in said pump housing in communication with said pressure chamber, a suction valve located in said piston bore, means fastening said suction valve to said pump housing to control fluid flow into said pressure chamber, and a piston slidably mounted in said piston bore whereby actuation of said piston in one direction creates a vacuum chamber in said piston bore whereby, fluid flows from said suction inlet bore, passed said throttle valve and inlet orifice into said vacuum chamber, and actuation of said piston in an opposite direction actuates said suction valve to pressure actuate fluid past said suction valve into said pressure chamber whereby fluid may flow through said high pressure outlet, a duct provided in said piston bore, and means in said pump housing for providing a conduit from said duct to said suction inlet bore, to provide for fluid located between said piston and piston bore to be recirculated, said pump housing further including a pressure regulating conduit having an outlet in communication with said pressure chamber, a regulating by-pass valve in said regulating conduit which by-pass valve regulates the pressure within said pressure chamber. 5. A high pressure pump for a sprayer as claimed in claim 4, in which said regulating by-pass valve comprises an adjustable needle valve located at the juncture of said pressure chamber and said pressure regulating conduit.

References Cited UNITED STATES PATENTS DONLEY J. STOCKING, Primary Examiner WARREN J. KRAUSS, Assistant Examiner U.S. Cl. X.R. 103-153, 221

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