US 3022742 A
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Description (OCR text may contain errors)
Feb. 27, 1962 R. LE BARON BOWEN, JR 3,022,742
PISTON PUMP Filed March 30, 1960 FIG.4 FIG-5 me. 6 H
INVENTOR. RICHARD LEBARON BOWEN,JR
ATTOR N EYS 3,022,742 PISTON PUMP Richard Le Baron Bowen, In, 35 Fessenden Road, Barringten, RI. Filed Mar. 3t), 1960, Ser. No. 18,677 2 Claims. ((31. 103-153) This invention relates to piston pumps, and more particularly to those of the metering type for handling fluids of a viscous nature, such as heavy oils, grease, slurries, pastes, plastic material, and the like.
Previously piston pumps which have been used for metering purposes have been provided with a suction along the bore and a discharge at one end thereof. It will be apparent that upon discharge a force is being exerted substantially longitudinally of the piston and material will tend to seep down alongside of the piston which no only makes the piston hard to reciprocate but also wears the piston whereupon a seal is quickly lost.
It is therefore an object of the present invention to provide a piston for a pump which will overcome some of the aforementioned disadvantages.
A more specific object of the invention is to provide a piston for a pump of general type mentioned wherein a recess is provided longitudinally of the piston at one side thereof remote from the suction opening so that a force will be exerted by the piston against the suction opening.
Also it is an object of the present invention to provide a piston pump with a suction opening along the bore and a discharge opening also along the bore spaced circumferentially about the bore with the axes thereof in the same plane normal to the axis of the bore together with a piston having a recess cut longitudinally therein adjacent the discharge opening.
With these and other objects in view the invention consists of certain novel features of construction as will be more fully described and particularly pointed out in the appended claims.
Referring to the drawings wherein like reference characters refer to like parts:
FIGURE 1 shows a top view partially in section of the preferred embodiment of the pump;
FIGURE 2 shows a side elevation of the pump of FIGURE 1;
FIGURE 3 shows a section of FIGURE 1 taken along lines 33;
FIGURE 4 shows a top view partly in section of an alternate construction of the piston of FIGURE 1;
FIGURE 5 shows an end view of the piston of FIG- URE 4;
FIGURE 6 shows a top view partly in section of another alternate form of the piston of FIGURE 1;
FIGURE 7 shows an end view of the piston of FIG- URE 6;
FIGURE 8 shows a section taken in the same location as FIGURE 3 of an alternate configuration of the pump body shown in FIGURE 1.
In FIGURE 1 there is shown a pump having a body, generally indicated by reference character 11, formed with a suction opening 12 and a discharge opening 13. Surrounding the discharge opening 13 and fastened to the body 11 is a housing 14 formed with a bore 15. Within this bore there is a ball check valve 16 and a spring 17, the spring urging the ball valve 16 against a seat 18 formed by the end of the discharge opening 13. Valve 16 is guided by means of vanes 19 formed within the bore of housing 14. Pump body 11 is provided with a bore 20 in which is fitted a piston 21, having one end thereof fastened to connecting rod 22 which is in turn connected to crank arm 23 fixed to the end of power shaft 24 turned by power means not shown, such as an electric States Fatent 3,922,742 Patented Feb. 27, 1952 the cut-otf point 31 in the suction opening. This structure forms a piston with a blunt end 32 that is preferable to using an inclined face. For instance, if the end of the piston comes to a sharp point, and if abrasive materials are handled, the leading edge wears very easily so that with time the rate of discharge will tend to decrease due to the wear. The present piston thus provides the maximum resistance to wear in contact with the wall of the bore 20. It should be further noticed that the shape of the piston 21 is such that the force exerted by the pressure of the fluid in forcing the end of the piston against the wall of the bore 20 surrounding the suction opening can be controlled, as shown in FIGURE 3. The force exerted is a function of the width P of the recess 30. As this width P is decreased the force is likewise decreased. FIGURE 3 also shows that we can control the length of this radial seal around the suction opening as indicated by angle A between the suction and discharge opening by varying the width P of the recess 30. As angle A increases the length of the seal increases and becomes A/X1rd, where d=diameter of piston.
FIGURE 4 shows an alternate arrangement of a piston for FIGURE 1. Here the width P of the recess in piston 41) has been decreased so that it is the same as the width 36 of the discharge Opening 13 at the bore 20 in FIGURE 3. However, in order to give the fluid a maximum area between the piston 40 and bore 20 to flow out through the discharge, slot 41 has been cut into piston 40. FIG- URE 6 shows still another alternative arrangement of a piston for FIGURE 1. Piston 42 now has the Width P of the recess reduced to a very minimum, but to give the material area in which to flow, a counterbore 43 has been provided in piston 42, and fluid flows through slot 44 cut through the Wall of the piston. It is evident that piston 42 provides the maximum circumferential length of sealing on both top and bottom between suction 12 and discharge opening 13, since the angle A in FIGURE 3 is at a maximum. Further, the force exerted on piston 42 tending to push it against the wall of bore 20 will be reduced in proportion to the width P of slot 44 if the width 36 of discharge opening 13 in FIGURE 3 is likewise reduced to the same dimension.
FIGURE 8 shows an alternate arrangement utilizing the principles of the invention where the suction and discharge openings are located circumferentially about the bore but not diametrically opposite the suction opening. In this embodiment the discharge is located at a right angle to the suction opening and lends itself to installations requiring other than in-line piping. From a practical standpoint, this orientation is a limiting case as the discharge can be visualized as being radially located anywhere between the showings of FIGURES 3 and 8. In this alternate arrangement pistons 21, or 40 or 42 can be utilized.
It will accordingly be apparent that there is disclosed herein an arrangement of a pump wherein sealing of the piston to the wall of the bore in which it reciprocates is enhanced together with an arrangement of suction and discharge openings which result in simple installations.
1. In a pump comprising a body having a bore therein, said bore having a uniform diameter throughout its length, a suction opening along said bore, a discharge opening along said bore, said suction and said discharge sesame openings being spaced circumferentially about the bore with the axes thereof in the same plane normal to the axis of said bore, a check valve positioned at said discharge opening, a piston of uniform diameter fitted for reciprocation in said bore having a sealing surface to close the suction opening and a longitudinal recess in said piston, said recess opening through the wall of said piston and extending from the free end thereof toward the other end a distance sufiicient to be in alignment with the discharge opening throughout its reciprocation, the surface area of said recess being greater than the cross sectional area of the suction opening whereby fluid pressure upon said surface area of said recess opposite the discharge Opening will exert a force in a direction normal to the axis of said piston and force the sealing surface of said piston against the end of said suction opening to tightly seal the same.
2. A pump as in claim 1 wherein said recess comprises a counterbore in said piston and a longitudinal opening through the wall of the piston facing in the direction of the discharge opening.
References Qiterl in the tile of this patent UNITED STATES PATENTS 2,685,987 Kaiser Aug. 10, 1954