US2689533A - Liquid pump - Google Patents

Description

Sept. 21, 1954 G. R. ERICSON LIQUID PUMP Filed Feb. 7, 1951 Ilia. 4

, FEE

INVENTOR charge nozzle I51.

Patented Sept. 21, 1954 UNITED STATES PATENT OFFICE LIQUID PUIVIP George R. Ericson, Kirkwood, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo., a corporation ofDelaware I ApplicationFebruary 7, 1951, Serial No. 209,798

this. type having. automatic yet simple and inexpensive means. for opening. the annular passage between the; piston and cylinder wall during the intake movements of the pump and for sealingly closing this passage during discharge movements. A further object'is to provide inapumplof this type. sealing. means for thepurpose indicated above which will conform to the mostminute irregularities invthe cylinder wall so-asto form a. liquid tight seal, and. which willbe freely movablewith respect tothe cylinder wall.

Further objects and advantages it will. appear from the specification andaccompanying drawings, inwhich-z.

Fig. Lisa sectional view of apumpappliedto a carburetor; i

. Fighiis afragmentary-side view of l the pump, partially sectionalized, showing the piston as it appearsduring. the discharge strokeg.

Fig. Sisa. fragmentary side view ofthe pump,-

partially sectionalized showing: the appears during theintake stroke; Fig 4, is a fragmentary side. view. of a modified form; of. my pump, partially sectionalized, show.- ing the. piston.- as it appears during the-discharge stroke; and. e l

Fig. isafragmentary. side view. of the modification, partially sectionalized, showing the pistonas it-appears during the intake stroke.

Referring. nowto the drawing, the-numeral [0 generally indicates a reciprocating pump com-- prising a cylinder H, piston I 2, outlet passages ll, having outlet checkvelve l4, therein, and dis- In the embodiment. shown, cylinder I lisslightly flared atits upper open end and forms partot the wall structure of a carburetor, generally indicated atl'll Carburetor l1 comprises a mixture conduit I8: flanged at its lower end or outlet for attachment to the intake manifold of an internal combustion engine and having: an air inlet I 9' at its upper end; a choke: valve 20; therein. for regulating the admis- 6 Claims. (Cl. 103178) piston as it I sion of air, stacked venturis 22, and a throttle valve 23 for regulating the discharge therefrom. Carburetor I! is also provided with a conventional constant level fuel chamber-24 in which the fuel level is controlled by float 25. Air at atmospheric pressure is admitted to chamber 24' through air vents 26. Fuel is supplied to the mixture conduit from chamber 24 by metering valve 21,. passage 28;

and. discharge nozzle 29, and by idle port 30 and associated passageways 30a. Additional fuelfor acceleration is provided by pump: l 0, locatedwithinthe constantlevel fuel chamber 24; cylinder I I of pump ID isopen at its upper end, its upper edge. being somewhat below the level of fuel in chamber 24, so as to be at all times submerged. Piston I2 is provided with a stem 31 connected at its upper end bylink 32 with lever 33 which is 'fulorumed at one end as at; in boss 35 on the fuel chamber cover. A link 31 connects the free ends of lever 33 andcrank 38 mounted on the throttleshaft, so that opening and closing movements of the throttle cause respectively downward and upward movements of piston I 2.

diameter than cylinder I It and-isformed'with an upper annular shoulder 44' of just slightly less diameter than the cylinder, so thatit forms with head element a substantially solid undersized piston having a. relatively deep annular groove 45 in its peripheral surface. Piston head-Misin form an inverted cup andhas formed in its upper surface a plurality of equally spaced radial oustwardly sloping slots 41, the purpose of which willbe seen below. An annulus 48, of circular cross-section; is mounted inannular groove 45. The outer diameter of annulus 48 is slightly greater than the inner diameter of pump cylinder ll, so as to be at all times in sealing engagement with the latter. The cross-section diameter of the annulus isslightly less than the height anddepth of groove 45 in" order to permit vertical movement of the annulus between the upper and lower edges of groove 45. This also permits liquid to flow from above collar 40, through the annular space between the periphery of shoulder 44 and the cylinder wall, and around the inner surface of annulus 48. when annulus 48 is in its lowermost position relative to piston 12, as shown in Fig. 3. It should be noted that, although an annulus of circular cross-section is shown in the drawings and described above, the annulus 48 may be of square, rectangular, or other crosssection. A coil spring 49 seated in the lower end of cylinder II normally urges piston I2 upwardly so that as throttle valve 23 closes, piston I2 is moved upwardly in submerged cylinder II, outlet check valve I4 seats, and a partial vacuum is created in that portion of cylinder below piston I2; due to the pressure differential on opposite sides of piston I2 and to frictional resistance between annulus 48 and the cylinder wall, annulus 48 seats on the lower edge of groove 45, and as the liquid above piston I2 is displaced by the piston, it flows around the periphery of shoulder 44, above andrinside of annulus 48, through slots 47, around the periphery of head 4| and into the portion of pump cylinder I below piston I2. As throttle valve 23 is moved toward open position, piston I2 is moved downwardly. The difference in fluid pressures on the upper and lower surfaces of annulus 48, and the slight frictional resistance between annulus 48 and the wall of cylinder H causes annulus 48 to sealingly seat against shoulder 44, thus obstructing the passage of fuel past piston I2. Thus, during downward movement, the escape of fluid past piston I2 is prevented and pump piston I2 forces the fuel below it through passage I3, outlet check valve I4, and discharge nozzle I5 into mixture conduit I8.

In order that it may accommodate itself readily to irregularities in the cylinder wall, and at the same time be easily slidable therein, annulus 48 is preferably made of a tough yet deformable gasoline resistant material having a low coeflicient of friction such as Teflon, a tetra'fluoroethylene resin made by E. I. du Pont de Nemours & Company. Teflon is deformable under pressure, but is of low resiliency, so that when forced through the slightly flared open end of pump cylinder II, a Teflon annulus readily conforms to the contour of the cylinder wall, to provide a sealing fit. Relatively free movement of the annulus with respect to the cylinder wall is facilitated by the low friction coeflicient of Teflon" (.09.12 on polished steel) and by the fact that due to its low resiliency, Teflon once conformed to surface irregularities of the cylinder tends to retain its conformation between successive movements of the piston.

Annulus 48 may also be formed of gasolineresistant synthetic rubber.

A modified form of my invention is shown in Figs. 1 and 5 in which the piston comprises shouldered collar 48 and head 58 mounted on the narrowed lower end portion 42 of stem 3|, and secured in abutting relation to each other and to the shouldered portion of stem 3| by a split ring or other securing means. The upper portion of head 58 is of frustro-conical shape sloping downwardly and outwardly so that it cooperates with collar 48 to form a substantially solid piston with an annular groove 5| in its peripheral wall. Groove 5| thus has a horizontal upper surface, a vertical inner surface and a downwardly and outwardly sloping lower surface 52. An annulus 48, as described above, is mounted in groove 5|. To retain annulus 48 in sealing engagement with shoulder 44 and to permit the passage of fuel between annulus 48 and lower surface 52 of groove 5|, an annular frustroconical wave spring 53, having substantially the same slope as surface 52 is interposed between annulus 48 and lower surface 52 of groove 5|. Frustro-conical wave springs are particularly suitable horizontal as well as vertical components so that they not only urge annulus 48 into sealing engagement with shoulder 44, but they also urge the annulus intosealing engagement with cylinder Wall II; even when compressed, wave spring 53 acts as a spacer between annulus 48 and sloping surface 52 to permit the flow of fluid therebetween, thus eliminating the need for slots in head element 58. During upward, or intake movements of the piston due to frictional resistance between annulus 48 and cylinder wall II and to the pressure differential applied to the upper surface of annulus 48, spring 53 is compressed as shown in Fig. 5. Thus, the fuel displaced by the upward movement of the piston is permitted to flow around the periphery of shoulder 44 between annulus 48 and the upper and vertical wall portion of groove 5|, between the corrugated surfaces of wave spring 53 and respectively, annulus 48 and sloping surface 52 and through the annular space between head 58 and cylinder wall into the portion of cylinder below the piston. On the downward, or discharge stroke, spring 53 expands, urging annulus 48 upwardly into sealing engagement with shoulder 44 and, if a resilient, flexible annulus is used, outwardly into more positive sealing engagement with the wall surface of cylinder II.

It is to be understood that pumps constructed according to this disclosure are adapted to a wide range of uses and are not limited to the embodiment disclosed herein; consequently, the exclusive use of all modifications of the invention as, come within the scope of theappended claims is contemplated.

What is claimed is: r

1. In a pump, a cylinder having aninlet end communicating with a supply of liquid and an outlet port in its opposite end, an undersize piston in said cylinder having an annular groove inits periphery, an imperforate annulus mounted for axial movement in said groove, said annulus being of larger internal diameter than the external diameter of any portion of the inner wall at the bottom of said groove in sealing engagement with the wall of said cylinder, fluid passage means connecting the inner portion of said groove and the space formed between the periphery of said piston and said cylinder wall, said fluid passage means being adjacent the portion of said annulus nearest the outlet end of said cylinder, and means for imparting reciprocating motion to said piston to engage said annulus with the edge of said groove adjacent the inlet end of said cylinder to close said fluid passage on the working stroke of said pump and to disengage said annulus on. reverse movement to open said passage.

2. In a pump, a cylinder having an inlet end communicating with a supply of liquid and an outlet port in its opposite end, an undersize piston in said cylinder having an annular groove in its periphery, an imperforate annulus mounted for axial movement in said groove, said annulus being of larger internal diameter than the external diameter of any portion of the inner wall at the bottom of said groove in sealing engagement with the wall of said cylinder, a plurality of radialslots in the edge of said groove nearest the outlet end of said cylinder to permit the emission of liquid from said groove, and means for imparting reciprocating motion to said piston to engage said annulus with the edge of said groove adjacent the inlet end of said cylinder to close said fluid passage on the working stroke of said pump and to disengage said annulus on reverse movement to open said passage.

3. In a pump, a cylinder havin an inlet end communicating with a supply of liquid and an outlet port in its opposite end, an undersize piston in said cylinder having an annular groove in its periphery, an imperforate annulus mounted for axial movement in said groove, said annulus being of larger internal diameter than the external diameter of any portion of the inner wall at the bottom of said groove in sealing engagement with the wall of said cylinder, a frusto-conical wave spring means on said piston lightly urging said annulus outwardly of said annular groove and into sealing engagement with the edge of said groove nearest the inlet end of said cylinder, fluid passage means connecting the inner portion of said groove and the space formed between the periphery of said piston and said cylinder wall, said means connecting the inner portion and piston periphery being adjacent the edge of said groove nearest the outlet end of said cylinder, and means for imparting reciprocating motion to said piston to engage said annulus with the edge of said groove adjacent the inlet end of said cylinder to close said fluid passage on the working stroke of said pump and to disengage said annulus on reverse movement to open said passage.

4. In a pump, a cylinder having an inlet end communicating with a supply of liquid and an outlet port in its opposite end, an undersize piston in said cylinder having an annular groove in its periphery, an annulus of tough, deformable material of low resiliency and with a low eoeflicient of friction on smooth metal surfaces being loosely mounted in said groove and slidable in said cylinder, said annulus being force-fitted into said cylinder to sealingly conform to irregularities in the wall structure thereof, a frustro-conical wave spring means on said piston lightly urging said annulus outwardly of said annular groove and into sealing engagement with the edge of said groove nearest the inlet end of said cylinder, means formed by said spring adjacent the edge of said groove nearest the outlet end of said cylinder for permitting the passage of liquid from the inner portion of said groove to the periphery of said piston, and means for imparting reciprocating motion to said piston to engage said annulus with the edge of said groove adjacent the inlet end of said cylinder to close said fluid passage on the working stroke of said pump and to disengage said annulus on reverse movementto open said passage.

5. In a pump, a cylinder having an inlet end communicating with a supply of liquid and an outlet port in its opposite end, an undersize piston in said cylinder having an annular groove in its periphery, an annulus loosely mounted in said groove, said annulus being constantly in sealing engagement with the wall of said cylinder, an annular frustro-conical radially corrugated wave spring interposed between said annulus and the edge of said groove nearest the outlet end of said cylinder to urge said annulus outwardly of said annular groove and into sealing engagement with the opposite edge of said groove, the spaces between the corrugations of said spring being adapted to permit the passage of liquid from the inner portion of said groove to the periphery of said piston, and means for imparting reciprocating motion to said piston to engage said annulus with the edge of said groove adjacent the inlet end of said cylinder to close said fluid passage on the working stroke of said pump and to disengage said annulus on reverse movement to open said passage.

6. In a pump, a cylinder having an inlet end communicating with a supply of liquid and an outlet port in its opposite end, an undersize piston in said cylinder having an annular groove in its periphery, an annulus of tough, deformable material of low resiliency and with a low coeflicient of friction on smooth metal surfaces being loosely mounted in said groove and slidable in said cylinder, said annulus being force-fitted into said cylinder to sealing'ly conform to irregularities in the wall structure thereof, an annular frustroconical radially corrugated wave spring interposed between said annulus and the edge of said groove nearest the outlet end of said cylinder to urge said annulus outwardly of said annular groove and into sealing engagement with the opposite edge of said groove, the spaces between the corrugations of said spring being adapted to permit the passage of liquid from the inner portion of said groove to the periphery of said piston, and means for imparting reciprocating motion to said piston to engage said annulus with the edge of said groove adjacent the inlet end of said cylinder to close said fluid passage on the: working stroke of said pump and to disengage said annulus on reverse movement toopen said passage.

References Cited in the file of this patent UNITED STATES PATENTS

Images