US2857219A - Pump - Google Patents

Description

Oct. 21, 1958 c. J. GRIFFITH ET AL PUMP 2 Sheets-Sheet 1 Filed Oct. 15, 1954 51 H LI,

lNVENTORS CLIFFORD J. GRIFFTH JAMES P. CARR ATTORNEY Pm f S Oct. 21 1958 c. J. GRIFFITH ET AL PUMP 2 Sheets-Sheet 2 Filed Oct. 13,1954

INVENTORS OLlFFORD J. GRIFFITH JAMES P. CARR -.9

BY y, www- ATTORNEY PUMP This invention "relatesto improvements inwpumps and "more particularly to improved means for controlling "the flow of fluid through areciprocatingpump.

In pumps used for circulating certain types of chemical *solutions, such as insecticides, it is 'very "important "that "none ofthe liquid bepermitted'to directly contact the moving parts of the pur'np or be'=permitted' to reach the *oil in the cra'nkcase, since many "'such'chemical "solutions will attack the connecting rod bearings and crankshaffbearin'gsof the pump causing considerable-damage. It is,accordingly, an objectof the pre'sent'inventio'n to provide a pump having novel means for preventing the liquid being pumpedfromi gaining access to the moving :p'arts of the' pump mechanism.

Another object is to provide an'improvedand simplified valve. arrangement "for a reciprocating pump.

' Another'object of the present invention is' to provide a novel; piston'for a reciprocating pump.

' Another=object "is to provide a" reciprocating pump that= is"-simple in construction and' efficient in "operation.

Other and further objects and advantages of thepresent invention will become apparent from the following description 'taken in=connection with 'the accompanying drawings; which: I

Figure "1 is a perspective view ofa. pump co'nstr-ucted in accordance with the teaching ofthe present invention.

Figure 2 is a central vertical sectional view taken 'on line 2-2 of Fig. 1.

Figure 3 -is' an enlarged elevation. taken along line 3-3 of Fig. 1, inlet and discharge conduits for the valve structure being shown.

Figiire lis an enlarged sectional'view taken on line of Fig. 3.

-Fig'ure '5 is an enlarged fragmentary sectional view "tak'enalong'line 5-5 of Fig. 4.

*"InfiFigs. l and 2 the reference numeral indicates lgenerally a hollowpump housing'having opposed side walls "'12 and opposed end walls '13. -"6f thehousing are integrally formed and have upper, in- "'wardl slanted portions 14 connectedat their top ends by an integrally. formed top wall 15whi'ch has two've'iti- All four walls cal bores "16 (Figure 2) formed therein. A-cross-head zllis r'nounted in each bore forwerti'cal reciprocation therein by means of a wrist pin 21, a connecting rod 22 and a crankshaft 23. The crankshaft is journaled for rotation in bearing assemblies 24 in spaced apertures 25 formed in the lower ends of the housing walls 12.

Each crosshead has an upwardly extending rod slidably journaled in a guide sleeve 31 which is rigidly secured in the upper end of the bore 16. A piston assembly 35 is mounted on the upper end of each crosshead rod and is arranged for sliding movement in a cylinder 36 provided by the internal surface of a sleeve 37. Each sleeve is disposed at its upper end in a recess 40 in a pumping head 41 and, at its lower end, in a recess 43 in a mounting plate 44 which is supported on and secured to the upper surface of a Wall 45 which is integrally rates Patent lQQ Q2 formed-on the housing and extends aroundthe uppenportion of the pump housing in spaced relation therewith.

It will be-seen that, when the crankshaft=is rotated by a power mechanism i not :shown) 'the .rpiston assemblies 5 "35 will be reciprocated in the cylinders. .It 'isito :be noted -thatthe pistons are *180out 'of phase so that, While one piston 'is on the suction stroke, the other pistonis-in-the discharge stroke. t

The pumping head- 41" is secured on'the upper end of 10 the'pump'housing by"bolts 48 (Figs! Z- and- IJ tha't'eX- tend through suitable openings 'in thepumping head and are threaded into tapped openings'in" the mounting plate '44. Thepumping head 41 has *two'flow passages 50 and 50a (Figs. 3 -and 4.) each of-which extends between 5 one of thepurnp'cylinders 36 and a cylindrical chamber 52. Each cylindrical chamber'52 is in-fiow communicationwith-an inlet ch'amberr60 through a port' 'fil and with a dischargechamberw63 through-a-port 64. 'Both of the inlet=-chambers-'60 (Fig. 3) are incommunication with 20 a common inlet conduit'66 through an internally'threaded passage 67 which receives one en'd of the. conduit. Simi- 1 larly, both' discharge'chambers fifi communicate with a "common discharge conduit-68 through an :opening: 69 in which thecon'duit 68318 threaded.

25 A featurerof the present invention isthe -novel valve arrangement for controlling the flow-of liquidfronr'each inlet chamber tc the associated edischarge chamber 63. Each 'valve assembly-comprises? an annular. inlet valve seat '7 0 (Fig. r4) arranged to fit: snugly in a-=reces's 30 '71-in the "pumping head *41. -E=The 'v'alve seathas *an is disposed in sealing engagement "between the-walls of the groove 73-and the wall of-t'he recess 71. x Resting on top ofthe seat 70 is a cylindrical: cage "78 whib'h '-hasapluralityof Vertical slots 79*throughwhich fluid may-pass. 'A solid-valve disk- 81'isvpositioned over-=the central opening "of the annular valve seat '70 to:close *thepassage formed therein. A-coil spring '83'is seatedlat its lower end "in-a recess formed in the "valve rdisk fll and bears at its upper end against an annular di'scharge valve seat- 85 which is "snugly disposed in "thetport 64 formed in the pur'rlpinghead. An -O ring88"is-'disposed in an annularigroove inth'e-discharge valve seat 85in sealing engagement between the outer surface of ithe 45 valve seat -'85and'-the inner surface 'of the port-'64. A solid valve disk 90 ispositioned over the central opening of'the annular'valve seat 8540 close the'passage'formed therein. A coil spring 91 :is 'seated at its 'lower 'erid in 'a recess formed in the valve disk. 90 and bears atriits upperfen'd against a cylindricalcover 92 which is 'disposed in a cylindrical passage 93 provided inthe "pumping head. A discharge cage 95 "rests :on top ofthe discharge valve-seat 85 with its'lowe'r tend extending "into: the :port -64 in the pumping head-41. 'The"cage 95'has a? plurality 55 -of-slots 96' through which :liquid may pass. ."A'res'ili'ent 'O-ring 97- is disposed in an annular. ggroove in the cover r92 in I sealing engagement :between i :the" cover and 'zthe pumping head. A bar 99 (Fig. 3) extends across the top of the pump housing and bears against both valve 60 covers 92 to hold the valve assembly in place. The bar 99 is locked in position by a capscrew 100 which extends through the bar and is threadedly received in the pumping head 41.

Referring to Fig. 4 it will be seen that when the pis- 65 ton 35 moves downwardly in its suction stroke, the inlet valve disk 81 is lifted off the seat 70 permitting liquid to enter the cage 78 and pass through the slots 79 of the cage 78 into the flow passage 50 and then into the cylinder 36. When the piston moves upwardly on a discharge 70 stroke, the valve disk 81 is forced down onto its seat 70, while the discharge valve disk 90 is forced ofi its seat 85 permitting the liquid to be forced through the slotted discharge cage 95 and out the discharge conduit 68.

Another feature in the present invention resides in the provision of means for effectively preventing the liquid being pumped from coming in contact with the moving parts of the pump. As seen in Fig. each piston 35 comprises a cup-shaped yieldable packing ring 103 which fits snugly inside the pumping cylinder 36. The packing element is sealed on the cross head rod 30 by means of a sharp circular projection, or ridge, 104 formed integrally with a Washer or pressure applying member 105. An O-ring 106 which is seated in a recess 107 in a back-up washer 108 seals the lower end of the packing element 103 to the rod'30. A capscrew 110 is threaded into a tapped opening in the upper end ofthe cross head rod and bears'against the washer 105 to press the sharp circular projection 104 into the yieldable upper surface of the packing ring to form an effective seal and to expand the O-ring 106 into tight sealing engagement with the cross head rod 30, thus preventing-the leakage of fluid downwardly along the surface of the'rod.

When leakage occurs around the outer circumferential edge of the packing element 103 due to wear, the downwardly moving liquid is deflected outwardly by a shield or hood 115 (Fig. 2) which has an upper cylindrical portion 116 disposed around the reciprocating rod 30 and locked between the back-up washer 108 (Fig. 5) and a shoulder 118 formed on the rod 30. A lower enlarged cylindrical portion 119 (Fig. 2) of the shield 115 extends, even in the uppermost position of the piston, to a point below the upper end of the bore 16 in which the cross head 20 reciprocates. The result is that liquid leaking past the cup will run down over the hood and be directed to the outside of the casing. With this arrangement it is not possible for such liquid to contact the cross head rod 30. 1 I I From the foregoing description it will b'e'evident that there is provided in the present invention a simple, effective valve arrangement for controlling the flow of liquid through a pump, and a positive gripping means'for preventing leakage of liquid at the point of connection of the piston with the piston rod. Further, the novel piston rod. hood provides an effective means for deflecting liquid away from the rod.

It will be understood that modifications and variations of the embodiment of the invention disclosed herein may be resorted to without departing from the scope of the novel concepts of the invention.

Having thus described our invention what we claim as new and desire to protect by Letters Patent is:

1. In a pump having a cylindrical pumping chamber, a piston comprising a rigid rod having a shoulder thereon, a rigid washer disposed around said rod above and adjacent to said shoulder, a packing ring of yieldable material disposed around said rod in abutting'contact with said washer and having a cylindrical surface in sliding contact with the wall of the cylindrical pumping chamber, a compressible seal ring disposed between said rigid washer and said packing ring and having an inner surface disposed around said rod, an apertured pressure-applying member disposed around said rod adjacent said packing ring, a ridge on said pressure member encircling said rod and in contact with said yieldable packing ring, and pressure-applying means for pressing said ridge into sealing engagement with said packing ring, said packing ring being arranged to transmit the pressure of said pressure-applying means to said seal ring to compress said seal ring and move said inner portion into sealing engagement with said rod.

2. In a pump having a cylindrical pumping chamber, a piston comprising a rigid rod having an outer peripheral shoulder, avrigid annular washer disposed around said rod above and adjacent to said shoulder, said washer having an annular recess in one face of the washer and adjacent said rod, a compressible seal ring disposed around said rod in said recess, a packing ring of yieldable material disposed around said rod in abutting contact with said washer and having a cylindrical surface in sliding contact with the wall of the cylindrical pumping chamber, and means for applying pressure to said packing ring to compress said seal ring and move it into sealing engagement with said rod and the walls of said recess.

3. In a pump for pumping liquids, means defining a cylindrical pumping chamber, a piston comprising a rod, a rigid washer of substantially the diameter of said chamber disposed around said rod and having a flat supportnig surface, a packing ring of yieldable. material disposed around said rod above and in abutting contact with said flat supporting surface and having a cylindrical surface in sliding contact with the wall of the chamber, an apertured pressure-applying member disposed around said rod above and adjacent to said packing ring, a ridge on said pressure-applying member encircling said rod and in contact with said yieldable packing ring, means for pressing said ridge into sealing engagement with said packing ring for preventing the passage of liquid inward toward said rod, and a shield disposed around said rod below and in abutting contact with said washer for deflecting liquid leaking past said piston away from said rod, said shield having a small diameter portion arranged to enter said cylindrical pumping chamber in spaced relation to the walls thereof and a large diameter portion disposed below the small diameter portion, said shield portions preventing access of the pumped liquid to the moving parts of the pump.

References Cited in the file of this patent UNITED STATES PATENTS 1,388,254 Hansen Aug. 23, 1921 1,413,568 Bjornstad Apr. 25, 1922 1,632,948 Cardenas June 21, 1927 1,825,483 Sprague Sept. 29, 1931 1,865,000 Goldberg June 28, .1932 1,881,951 Rayfield Oct. 11, 1932 1,976,464 Shallenberg Oct. 9, 1934 2,049,570 Schoene Aug. 4, 1936 2,081,224 Coberly May 25, 1937 2,325,672 Grofi Aug; 3, 1943- 2,365,237 Allen Dec. 19, 1944 2,623,798 Skinner Dec. 30, 1952

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