US 2702008 A
Description (OCR text may contain errors)
Feb. 15, 1955 J. M. STOCKARD 2,702,008
PUMPING APPARATUS Filed June 9, 1952 INVENTOR.
JOHN M. STOCKARD Q4 42 675%.. J. c. an
ATTORNEYS 2,702,008 Patented Feb. 15, 1955 2,102,00s PUMPING APPARATUS John M. Stockard,.Washington, n. -c., assignor to the UnitedStates of America as represented by the Seeretary of the Navy Application June 9, 1952, Serial No. 292,600 q 61 Claims. (Cl. 103-168) (Granted under Title35, U. s. Code 1952 see. 266) The invention described herein maybe manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
This invention relates to improvements in liquid pumps of general utility.
One'of the objects of the invention is to provide a positive displacement reciprocating multi-piston type liquid pump, the pistons of which are mechanically actuated through their discharge strokes and hydraulically actuated through their return or suction strokes.
Another object is-to provide a pump piston and cylinder construction which minimizes requirements for certain close tolerances in the manufacture thereof.
Another object is to minimize the number of working parts which are exposed to the liquid being pumped.
Further objects 'are to provide a simplified construction which is economical: of manufacture and has quantitative accuracy of discharge rate.
Still further objects and many 'of the attendant advantages of this invention will be readily appreciated as the same because better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Fig. 1 is a top plan of one embodiment of the invention, portions being broken away;
Fig. 2 is an enlarged section taken on line 2-2, Fig. l, the conduit system being shown diagrammatically;
Fig. 2A is a section like Fig. 2 with the various parts shown in dilferent positions of operation.
Fig. 3 is a fragmentary section, similar to Fig. 2, of another embodiment of the invention; and
Fig. 4 is a longitudinal cross section through a check valve and conduit which may be employed in the construction of any of the preceeding figures.
Referring in detail to the drawing, the first embodiment of the invention previously referred to comprises, in general, a frame of any suitable form to which is aflixed a first pair of opposed cylinders 11, 12 and a second similar pair of-cylinders 11a, 12a. A shaft 13 is journaled in bearings 14, 15, 16, affixed to frame 10, the shaft having a pair of eccentrics 17, 17a thereon disposed in 180 phase relationship. Eccentrics 17, 17a are provided, respectively, with encircling anti-friction bearings 18, 18a, which may be of the ball or roller type.
Cylinder 11 is provided with a bore 19 containing a piston or plunger 20 and a larger bore 21 containing a piston 22. Cylinder 12 is similarly proved with a bore 23 containing a piston 24 and a bore 25 containing a piston 26. Cylinders 11a, 12a are provided with similar pistons 20a, 22a and 24a, 26a, respectively. The large and small pistons in each of the cylinders are preferably separate elements which abut at adjacent ends within the larger bore.
A conduit 27 having a check valve 28 therein hydraulically connects bore 25 and bore 19. A conduit 29 having a check valve 30 therein connects bore 25 and inlet conduit 31. A conduit 32 having a check valve 33 therein connects inlet conduit 31 and bore 21. A conduit 34 having a check valve 35 therein connects bore 23 and discharge conduit 36. A conduit 37 having a check valve 38 therein connects bore 23 and bore 21. A conduit 39 having a check valve 40 therein connects bore 19 and discharge conduit 36. The check valves just described may be of any suitably type, such as valve V, shown in Fig. 4, having a ball 41, urged on seat 42 by spring 43.
In the operation to now be described it will be assumed that the system has been primed with liquid and shaft 13 is rotating clockwise, as shown in Fig. 2, wherein pistons 26 and 24 are being movedto the right by eccentric 17 and bearing 18. The pressure of the liquid in bore 23 is transmitted to valve 38 through conduit 37,
' maintaining valve 38 closed. This pressure also maintains valve 35 open and the liquid from bore 23 flows through conduit 34 to discharge conduit 36. The pressure of the liquid in bore 25 maintains valve 30 closed and valve 28 open, the liquid flowing through conduit 27 to bore 19, where it forces piston 20 to the right, the right end of piston 20 forcing piston 2210 the right and maintaining the right end of the latter in contact with bearing 18. Surplus liquid, not-required toeffect the operation just described, flows through conduit 39,
maintaining valve 40 open, and thence to discharge conduit 36. Piston 22 is now on its suction stroke, valve 38 is closed as previously described, valve 33 is open, and liquid flows from inlet conduit 31 to bore 21 through conduit 32.
It will now be assumed that the eccentric has rotated to the position shown in Fig. 2A wherein pistons 22 and 20 are being moved to the left by eccentric 17 and bearing 18. The pressure of the liquid in bore 19 is trans mitted to valve 28, through conduit 27, maintaining valve 28 closed. This pressure also maintains valve 40 open and the liquid from bore 19 flows through conduit 39 to discharge conduit 36. The pressure of the liquid in bore 21 maintains valve 33 closed and valve 38 open, the liquid flowing through conduit 37 to bore 23, where it forces piston 24 to the left, the left end of piston 24 forcing piston 26 to the left and maintaining the left end of the latter in contact with bearing 18. Surplus liquid, not required to effect the operation just described, flows through conduit 34, maintaining valve 35 open, and thence to discharge conduit 36. Piston 26 is now on its suction stroke, valve 28 is closed, as previously described, valve 30 is open, and liquid flows from inlet conduit 31 to bore 25 through conduit 29.
Conduits 37a, 39a, as shown in Fig. 1, correspond, respectively, to conduits 37, 39. Conduits 27a, 34a correspond, respectively, to conduits 27, '34. The conduit and valve system for cylinders 11a,12a is the same as for cylinders 11, .12 and it will be apparent that the operation will be the same except that the two sets of cylinders are operating at phase relationship. The inlet and outlet conduits for the two sets of cylinders may be common, respectively, to both sets of cylinders or they may be separate so that two different liquids may be pumped. The relative diameters of the pistons may be varied as desired but it will be apparent that the cross sectional area of the annulus around piston 24 in bore 25, for example, should be at least equal to the cross sectional area of piston 20 so that piston 26 will supply sufficient liquid to fill bore 19 and maintain piston 22 in contact with bearing 18. Preferably, however, the annulus referred to will be greater in area than the cross sectional area of piston 20, the surplus liquid discharging through conduit 39, as previously described. It will be apparent, also, that the relationship of crosssectional areas of pistons 22 and 24 will be as just described so that piston 26 will remain in contact with hearing 26 on its return or suction stroke.
In the form of the invention shown in Fig. 3 cylinders 111, 112 correspond, respectively, to cylinders 11, 12, and cylinders 111a, 112a correspond, respectively, to cylinders 11a, 12a, all of the pistons contained therein being disposed angularly in the same plane and operated by a single eccentric, rather than by separate eccentrics as previously described. It will be understood that the conduit and valve system in this arrangement of cylinders is the same as employed in the first embodiment of the invention.
It will now be apparent that any number of sets of cylinders may be employed in the arrangement shown in Fig. l by merely adding more eccentrics to shaft 13. Similarly, a plurality of parallel bank of cylinders may be employed with the construction shown in Fig. 3.
As previously referred to, the pistons in each cylinder are se arate elements. This construction has the advantage at close tolerance for axial alignment of the large and small bores is unnecessary, thus efiectiug-economy of manufacture. Also, since the pistons do not require any stepped surfaces they may be ground from stock slightly greater in diameter than theirfinished sizes, thus efiectmg a saving of considerable material over an integral piston construction. As will be apparent, also, that the machining operations for separate pistons is also simplified over an integral stepped construction. It is to be understood, however, that the operation of the invention does not depend upon the separate piston construction described, this being principally to etfect economy of manufacture, and if so desired, the large and small pistons may, within the purview of the invention, be formed integrally or joined integrally in any manner apparent to those skilled in the art.
It will also be apparent that the anti-friction hearing may be omitted and the eccentric bear directly on the ends of the larger pistons. Also, the cam means, shown in the form of a circular eccentric, may be of any other desired cam shape and a plurality of cam lobes may be employed to effect a plurality of piston cycles of operation per revolution of the rotating shaft, rather than only one cycle, as illustrated.
Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
1. Liquid pumping apparatus comprising; first pumping means including first and second bores disposed in tandem relationship, the first bore being of greater diameter than the second bore, a first reciprocable plunger slidably disposed in the first bore, a second reciprocable plunger slidably disposed in the second bore, the plungers being arranged to provide 'a first expansible annular chamber/ in the first bore around a portion of the second plunge'r,
the ends of which are defined by an end of the-first plunger disposed within the first bore and a wall at an end of the first bore, and a second expansible chamber in the second bore defined by an end of the second plunger disposed within the second bore and a wall at one end of the second bore, cam means operatively engaging the other end of the first plunger for moving both plungers in a direction to reduce the volumes of said chambers, second pumping means operatively engaging the cam means having bores and plungers forming first and second chambers similar to the chambers of the first pumping 0 means, conduit means communicating the first chamber of the first pumping means with the second chamber of the second pumping means when the chambers of the first pumping means are decreasing in volume, whereby liquid discharged from the first chamber of the first pumping means hydraulically forces the plungers of the second pumping means to increase the volumes of the chambers of the second pumping means, conduit means communicating the first chamber of the second pumping means with the second chamber of the first pumping means when the chambers of the second pumping means are decreasing in volume, whereby liquid discharged from the first chamber of the second pumping means hydraulically forces the plungers of the first pumping means to increase the volumes of the chambers of the first pumping means, conduit means for discharging liquid from the second chambers of both pumping means when such chambers are decreasing in volume, and conduit means connecting the first chambers of both pumping means with a source of liquid when such chambers are increasing in volume.
2. Apparatus in accordance with. claim 1 wherein the plungers of each pumping means are separate elements with adjacent ends in abutting relationship, whereby the first plunger may move the second plunger during one direction of movement but may not move the second plunger during its opposite direction of movement.
3. Apparatus in accordance with claim 1 wherein the first chamber of the first pumping means is larger in cross section than the second chamber of the second pumping means, and the first chamber of the second pumping means is larger in cross section than the second chamber of the first pumping means.
4. Apparatus in accordance with claim 1 wherein said cam means includes a rotatable eccentric.
5. Apparatus in accordance with claim 4 wherein the periphery of the eccentric is provided with an antifriction bearing, the latter engaging an end of the first plunger of each pumping means.
'6. Apparatus in accordance with claim 1 wherein the longitudinal axes of the plungers of both pumping means are disposed substantially along a single axis.
References Cited in the file of this patent UNITED STATES PATENTS 1,850,083 Noltein Mar. 22, 1932 2,337,510 Trevaskis Dec. 21, 1943 FOREIGN PATENTS 23,418 Sweden Nov. 9, 1907 256,603 Germany July 24, 1912 745,626 France Feb. 21, 1933 922,415 France Feb. 3, 1947