US2271570A - Pump - Google Patents

Description

Feb. 3, 1942. s PARD'EE rum? Filed July 51, 1940 2 Sheets-Sheet 1 Feb. 3, 1942. H. s. PARDEE PUMP Filed July 31, 1940 2 Sheets-Sheet 2 Patented 1 .1.3. 1942' ,UNITED STATESFPATENT OFFICE Applica i o z 1Ei :STl;, S e ri:l 1 V: 348,G42

20 Claims.

This invention relates to pumps, and with regard to certain more specific features, to highpressure, hydraulic pumps.

Among the several objects of the invention may be noted the provision-of a reliable highpressure, hydraulic pump, particularly (though not necessarily exclusively) for low-volume operations, which hasthe simplicity of a rotary pump but does not require its complications such as a vacuum or suction shaft seal; the provision of a pump of this class which is designed particularly for high velocities with high mechanical and volumetric efliciency and which will handle dirty pumpage if necessary; and the provision of apparatus of this class which is simple and compact. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is illustrated one of various possible embodiments of the invention,

Fig. 1 is a side elevation;

4 Fig. 2 is a right-end elevation of Fig. 1;

Fig. 3 is a vertical section taken on line 3-3 of Fig. 1;

Fig. 4 is a vertical section taken on'line 4--4 of Fig. 1 but enlarged;

- Fig. 5 is a longitudinal section taken on line 55 of Fig. 4;

Fig. 6 is a perspective view of a pump plunger and its separated driving slipper; and,

Fig. 7 is a perspective view-of a plunger returnspring, on a reduced scale.

.Similar reference characters indicate corresponding parts throughout the several views of the drawings.

Referring now more particularly to Fig. 1, there is shown at numeral I a pump casing or body which, by means of studs I (see also Fig. 5), is attached to the adaptor 3 of a motor casing 5. The adaptor 3 of the motor casing 5 is held by means of studs 9.

The adaptor 3 of the motor casing 5 forms the support for a bearing II, in which rotates the drive shaft I 3 for the present pump. The

driv shaft 13 may be operated from any suitable source, such as by a shaft of an electric motor, aeroplane engine, or the like, depending upon the application to which the present pump is put. Application to pressure-control systems is an exemplary use of the vention.

The bearing II is sealed as shown at l5. At I1 is shown an enclosing head which is bolted present into the body I to form, with the seal IS, a sealed enclosure for the driving parts. The seal here referred to is not the avoided seal specified in the above objects. The latter is the vacuum shaft seal necessary in rotary vane and centrifugal machines which are subject to the suction pressure. The pressure carried within I, 3 and I1 is normally atmospheric. Splash lubrication is used, as will appear.

The driving parts include a circular eccentric I 9 keyed to an extension 2'! on said shaft I3. Borne on the eccentric l9 by means of needle bearings 23 is a cylindric sleeve 25. The needle bearings are held from endwise escape by washer plates 29.

Bearing on the outer periphery of the sleeve are four crescent-shaped slippers 21. One slipper is as shown in Fig. 6 and comprises an outer cylindrical bearing 29 and endwise walls or flanges 3| with comer recesses 32 and chamfers at 34. The circular bearing 29 is for the purpose of fitting the circularly formed end 33 the plunger 35, to serve as lateral holding guides. The bottom of each slipper is curved as shown at 31, the radius of curvature being equal to the radius of the sleeve 25.

In operation, there is some sliding motion forward and. backward during each revolution, between the slipper 21 and the sleeve .25, due to the varying angular distances caused by the different eccentric positions.

Each plunger 35 slides in a sleeve 39. The sleeves are pressed into suitable openings in the body I, as shown in Figs. 4 and 5.

. Each sleeve 39 is open at its outer end and is machined flat with an optical fiat at 4|. Each sleeve is also open at its inner end to permit of extending the respective plunger to its slipper 21. Each sleeve is also provided with inlets 43 within a recess 45. This recess 45 registers with The recess 41 communicates with and formspart' of the suction chamber 49 which is cored into the-body l in an inner peripheral form. This suction chamber 49 is in communication with the suction inlet shown to the right at 5| (Fig. 4). As indicated, the upper edges of the inlets 43 in the sleeves 39 are straight (see numeral 53).

Normally seating on each machined optical tions between said plungers.

flat d! is a valve cup 55 which is normally biased to its seat by means of a spring 55. The inner ends of the cups 55 are also optical flats. Each spring 5! reacts from an enclosing cap 59 which is threaded into the opening through which the respective sleeve 39 is applied for force-fitting into the respective more or less radial opening M.

The outer peripheral exhaust or outlet chamber 63 of the pump is cored out circularly around, and spaced from, the inlet passage t9 and is in communication with the open ends of the sleeves 39 when the valves 55 are lifted.

The stroke of each plunger 35 in each sleeve 39 is such that the end 62 thereof moves from a point within the outer edge of the openings 43, to direct contact (if'necessary) with the bottom of the valve 55. As a plunger contacts its valve 55 (when this occurs)", there is an additional slight movement of the order of about .005, or just enough to take up all clearance, and to give the pump a slight negative clearance. This is for the purpose of assuring that all of the conyielding force which will accommodate itself to the small change in distance between the holes in opposite plungers.

As will beseen by examination of Fig. 4, the center lines of opposite sleeves 39 and plungers 35 are not co-axial, although parallel, and are offset on opposite sides of the center of shaft 2|.

The oifset is in a direction so that the driving 'thrust through the center of the eccentric will on an average more nearly be directed along the center line of each plunger 35 upon the compression stroke, than on the suction stroke. This means that the respective slipper 21 is least angled with respect to its plunger 35 upon the tents of each sleeve 39 will be emptied upon each compression stroke, including any air or gas which might otherwise re-expand upon the suction stroke. All fluid pumped into and through the outlet chamber 63 is ultimately forced to the pump outlet shown at numeral 65. Ordinarily, the liquid forced out by the plunger 35, unseats the valve cup 55 but should a slug of air or the like he encountered this is positively completely forced out by the contact of the plunger 35 with the valve cup. No re expansion of any air in a clearance space is possible because there is no clearance space.

Each sleeve 39 is slotted, as indicated at 61'. At a position adjacent the respective slot 61, each plunger 35 carries an opening 63 which is drilled at a slight angle with respect to the axis of the plunger. This is for the purpose of receiving and holding a hook end H of an arcuate or bowed spring 12 (see Fig. 7).

Each spring 1'2 has its hook-shaped 'ends H placed in openings 69 of oppositely located plungers 35. It is clear from Fig. 5 that the effective lengths of the hooks of one pair of springs l2are greater than the effective lengths of the hooks of the other pair, so that the arcuate portions of these springs may lie in difierent planes. Each spring 12 is so formed that in placing it as above described, the hooks ll need to be spread somewhat so as to cause the oppositely located plungers to be drawn toward one another. Hence they bear upon their respective slippers 21, which in' turn bear upon the sleeve 25. Thus each slipper is pressure-confined. The springs 12 are in moderate tension at the closest relationship between opposite plungers. The bow of each spring lies radially outside the orbit of the sleeve 25.

An advantage of having the spring connector 12 carried between oppositely located moving plungers 35 is that the spring connectors thus move back and forth with the plungers, while at the same time they'respond to any relative mo- Since oppositely located plungers are always moving in parallel directions at nearly the same rates, their relative motion is slight, this means that the spring deflections for maintaining the slight differences in position clue to relative motions are small and much less than the stroke of each plunger. Thus the force holding each plunger and slipper biased compression stroke, and most angled upon the relatively light suction stroke when drawn back by the respective spring 5! (compare oppositely located slippers in Fig. 4). By least. angled here is meant the least angle with respect to a condition of symmetry between slipper and plunger.

Operation is as follows:

Rotation of the eccentric l9 causes oscillation of the sleeve 25. This oscillation of sleeve 25 does not necessarily mean that it rotates with respect to the frame of the machine. When any plunger is in a position nearest the center, its inner end is closer to the inner end of an adjacent plunger and likewise when the plunger is furthest out the angular distance between the inner end of this plunger and the inner ends of its adjacent plunger is a maximum. Thus the slippers constantly move toward and away from each other, sliding on the periphery of the sleeve. The slipper provides a surface contact instead of a line contact between the plunger and sleeve. This makes possible film lubrication and minimizes wear and frictional losses.

As the sleeve 25 oscillates, the slippers 21' are reciprocated along lines parallel to radial lines and at the same time they are oscillated with respect to the plungers 35', which are reciprocated Upon its suction stroke each plunger is drawn back by the driving movement of the opposite plunger (through.

the spring 12 acting as a drag link). This draws in fluid from the chamber 49 and upon a compression stroke forces fluid out past the respective valve into the outlet chamber 63 and to the .outlet 65. i

Each plunger 35 is sprung down against its slipper 21, and each slipper 21 is sprung down against its sleeve 25 by means of the action of the respective spring 12 engaging the opposite plunger. This is in addition to the drag above mentioned. It may be-remarked that the opposite openings 69 do not retain a constant separated distance during the cyclic action of the eccentric [9. The variation, due to the geometry of the apparatus, is compensated for by the resiliency of the respective spring 12 which spans the respective pair of openings 69. It will be understood, although the pump shown is a fourcylinder arrangement, that other multiples pref erably even) may be used.

Although the eccentric I9 is located in a sealed chamber and runs in lubricant which may be supplied through a cup 15 and removed for replenishment from a cup 11; nevertheless, nohighpressure packing is employed. The lower ends of the plungers 35 require no packing because of the lap fits.

A favorable field of usefulness for the device is in small capacities at high pressures. A pump made according to the disclosure herein has operated at 6000 R, P. M. with little loss of volumetric efllciency. Another has operated at 3500 R. P. M. at a liquid pressure of 4000 pounds per 4 square inch with a volumetric efficiency of practically 100% and a mechanical efllciency of about, 92%. Another operates at 5000 R. P. M. at 3000 pounds per square inch.

In view of the above, it will be seen that \the several objects of the invention are achieved and other advantageous results attained.v

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim: e

1. A pump comprising a cylinder, a reciprocating plunger in the cylinder, rotary eccentric means, a rotary sleeve on the eccentric means and a slipper between the plunger and the sleeve on the eccentric'means, said slipper having a contact surface with the plunger constituting a partial cylinder, and another contact surface with the sleeve constituting another partial cyllinder. v

2. A pump comprising opposite cylinders, reciprocating plungers in the cylinders, rotary eccentric means between the cylinders, a rotary sleeve on the eccentric means, slippers between the respective plungers and the sleeve on the eccentric means, each slipper having a contact surface with its respective plunger. constituting a partial cylinder, and another contact surface with the sleeve which constitutes another partial cylinder, and spring means carried by the plungers and biasing them toward one'another while moving with them.

3. A pump comprising a cylinder, 9. reciprocating plunger in the cylinder, an eccentric, a sleeve in which the eccentric rotates, and a slipper between the plunger and the sleeve, said slipper having an arcuate contact surface with the plunger, and another arcuate contact surface with the sleeve. v

4. A pump comprising a cylinder, a reciprocating plunger in the cylinder, an eccentric, a sleeve n the eccentric, and a slipper between the plunger and the sleeve, said slipper having an arcuate contact surface with the plunger, and another arcuate contact surface with the sleeve, the axial center line of the plunger being offset withrespect to the center of rotation of said eccentric in a direction such that the line of thrust is at a minimum average angle with respect to the plunger upon a compression stroke.

5. A pump comprising rotary eccentric means, plungers located on opposite sides of the eccen'- tric means, said eccentric means reciprocating the plungers, spring means reacting between the plungers and moving with them to bia said plungers against the eccentric, said spring means comprising an arched spring carried between plungers and clearing the eccentric in the plane of its movements. and sleeves in which the plungers reciprocate, said sleeves having guide slots cooperating with the springto maintain said spring in a predetermined plane.

6. A pump comprising rotary eccentric means,

plungers which are not co-axial located on opposite sides of the eccentric means, spring means reacting between the plungers normally to force them against the eccentric means, and

slippers rotary with respect to the plungers and forming bearings. therefor, said slippers having arcuate bearing surfaces on the eccentric means. 7. A pump comprising rotary eccentric means, plungers which are not co-axial located on opposite sides of the eccentric means, spring means reacting between the plungers normally to force them toward and against the eccentric means, and slippers rotary with respect to the plungers and forming bearings therefor, said slippers having arcuate bearing surfaces on the eccentric means, said spring-biasing means comprising an arched wire having attachments to the plungers.

8. A pump comprising eccentric means, a reciprocating plunger, and a crescent-shaped slipper between the eccentric means and the plunger having a concave arcuate surface contacting the eccentric means and a convex arcuate surface contacting the plunger. 9. A pump comprising eccentric means, a reciprocating plunger, and a crescent-shaped slipper between the eccentric means and the plunger having a concave arcuate surface contacting the eccentric means and a convex arcuate surface contacting the plunger, the rotary axis of the eccentric means being outside the pressure axis of said plunger.

10. A pump comprising eccentric means, a

the suction chamber and having inlets communieating therewith, said cylinders having outlets in the outlet chamber, check valves biased to seat over the outlets, radial plungers having ends moving from radial positions within the inlet to force fluid from the outlets, said body portion having an open center, and said cylinders having outlets in said center, operating means within said open center, said operating means comprising an eccentric, a sleeve around said eccentric and having a bearing thereon, plungers in said cylinders, slippers between the sleeve and the plungers, said slippers'having oscillating contact with the plungers and a to-and-fro relative angular movement, and spring-biasing means between opposite plungers and movable therewith and shaped to clear the eccentric driving means. 12. A pump comprising at least two opposed cylinders, a reciprocating plunger in each cylinder, eccentric actuating means interposed between saidplungers and reacting in thrust against the plungers to force them through their displacement strokes, the plungers being approximately radial with respect to the operating periphery of the eccentric means and substan tially in its plane of rotation, yielding connecting-means between said plungers comprising an arched spring which clears the eccentric means in all positions of the latter, said connecting means being mounted under suificient initial stress to ensure that each plunger will be drawn through its suction stroke by the other plunger without substantial lost motion between the plunger so drawn and said eccentric means.

.13. A pump comprising a pair of cylinders, said cylinders having lateral inlet ports formed in their walls, reciprocating plungers respective- 1y inthe cylinders controlling said inlet ports, eccentric means interposed between said plungers and serving to actuate them alternately in thrust on their discharge strokes, the plungers being approximately radial with respect to the operating periphery of the eccentric means and substantially in its plane of rotation, the parts being so dimensioned that the plungers open the inlet ports at the innermost end of their'strokes,

and a yielding connection between said opposed plungers comprising an arched spring which clears the eccentric means in all positions of the latter, said connection being of sufficient strength and mounted under sufficient initial stress to cause each plunger to draw the other through its suction stroke without substantial lost motion between the plunger so drawn and said eccentric means.

14. In a pump, the combination of a rotary shaft carrying an eccentric, asleeve rotatably mounted on said eccentric, a pair of opposed cylinders, said cylinders having slots in their proximate ends, a plunger working in each cylinder, each plunger having a spring seat which aligns with the slot in its cylinder, and a cylindrical slipper-seat in the end of the plunger, slippers, one for each plunger, each having a convex cylindrical journal surface which works in the slipper-seat of the corresponding plnn-ger' and a concave cylindrical bearing surface which engages said sleeve, means limiting movement of each slipper transverse to its plunger and paral lel with the axis of the sleeve, and an arcuate spring having hooked end portions which project from the plane of such are and extend through the slots in respective'cylinders into engagement with the springv seats of respective plungers, said spring being sufiiciently stressed in tension to maintain the plungers, slippers and sleeve in coactive thrust engagement.

15. The combination defined in claim 14 in -which thespring is so bowed that it lies radially '17. The combination defined in claim 14 in which inlet ports are formed in the cylinder yielding, while such inlet port is closed off bythe plunger.

'18. In a pump, the combination of a rotary shaft carrying an eccentric, a sleeve rotatably mounted on said eccentric, a pair of approximately radially opposed cylinders mounted with their axes parallel but offset in opposite directions from the axis of said shaft, said cylinders having slots at their proximate ends, a plunger working in each cylinder, each' plunger having a spring seat which aligns with the slot in its cylinder, and a cylindrical slipper-seat in the end of the plunger, slippers, one for each plunger, each having a convex cylindrical journal surface which works in the slipper-seat of the cor responding plunger and a concave cylindrical bearing surface which engages said sleeve, means limiting movement of each slipper transverse to its plunger and parallel with the axis of the sleeve, and an arcuate spring having hooked end portions which project from the plane of such are and extend through the slots in respective cylinders into engagement with the spring seats of respective plungers, the spring being sufflciently stressed in tension to maintain the plungers,

slippers and sleeve in coactive thrust engagement.

19. In a pump comprising a frame forming a housing, a supporting bearing in one side of said housing, an eccentric having a rotary mounting in said bearing and overhanging within the housing, radial cylinders in the housing, plungers in the cylinders, removable means at the ends of said cylinders permitting radial removal of the plungers through the cylinders, bearing means between the plungers and the eccentric, and spring means vyieldingly connecting opposite plungers to force them toward one another and the eccentric, said spring means being located on the overhung side of the eccentric opposite its rotary bearing, and a removable cover on said housing opposite the overhanging eccentric, whereby upon removing the cover said springs are exposed for disassembly without disturbing the eccentric, and whereby said plungers and bearing means may be removed without disturbing said eccentric.

20. In a pump, a housing, a supporting hearing in one side of said housing, an eccentric having a'rotary mounting in said bearing and overhanging within the housing, radial cylinders in the housing substantially in the plane of the cocentric, plungers in the cylinders, removable heads at the ends of said cylinders permitting radial removal of the plungers through the cylinders', pressure-confined bearing means between the plungers and the eccentric, and spring means yieldingly connecting opposite plungers to force them toward one another and the eccentric to effect said confinement, said spring means being located on the overhung side of the eccentric opposite its rotary bearing, said bearing means being separable from the plungers and the eccentric simply by removing the plungers and being held in place by said spring, and a removable cover on said housing opposite the overhanging eccentric, whereby upon removing the cover said springs and said plungers and bearing means may be removed without disturbing said eccentric.

HARVEY S, PARDEE.

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