US2861520A - Differential piston pump - Google Patents

Description

NOV- R. J. LlNnsEY 2,861,520

DIFFERENTIAL FIsToN PUMP Filed July 19, 1954 L W 79g gg 30 Y INVENTM ,2 51.1 78 M fha/HQ gru DIFFEREN'HAL PISTON PUMP Robert .1. Lindsey, Cincinnati, Ohio, assignor to American Iteel Foundries, Chicago, Ill., a corporation of New ersey Application July 19, 1954, Serial No. 444,005

4 Claims. (Cl. 10S-153) This invention relates to a fluid pump and more particularly to a reciprocating plunging type pump especially adapted to generate high working pressures.

Conventional pumps heretofore employed in the art have presented a problem when it is desired to develop high working pressures. lf the working area of the fluid contacting piston is relatively large, an extremely expensive drive or power source is required to develop the power necessary to reach the desired working pressure. This additionally entails increased size and strength of connecting mechanism such as crank arms and bearing areas in order to adequately carry the required load, which also adds additional expense to the units and renders said units undesirable from a size standpoint. The alternative to these undesirable features usually practiced in the art, is to materially reduce the piston or plunger area by designing it to be a long slender rod whereby high working pressures may be developed on a relatively small fluid working area, thereby avoiding the increases in size and power mentioned above. It has been found, however, that this alternative is not without operating diiiiculties, the most .prominent being that the rod or plunger employed frequently fails from buckling due to the relatively high column or compressive loads.

Accordingly, it is a primary object of the invention to provide a pump of the type described wherein the mentioned difficulties are solved.

It is another object of the invention to provide a pump of the type described which employs a differential piston plunger to alleviate the mentioned problems.

It is the specific object of the invention to provide a pump of the type discussed wherein the piston rod or plunger is provided with a guide tail or rod whereby the plunger presents a relatively small working area, thus developing high working pressures, while the rod itself is relatively heavy in section thus eliminating the prior art tendency to buckle under axial loading.

These and other objects of the invention will become apparent from an examination of the following specification and the associated drawing, wherein:

The ligure is a vertical sectional view through a typical pump arrangement embodying the invention.

Describing the invention in detail and directing attention to the gure associated herewith, it will be seen that the pump arrangement comprises a base 2, said base 2 having a lower section 4 and upper section 6. The upper section 6 may be considered as the working section of the pump and is provided with a working chamber indicated by the numeral 8. On opposite sides of the section 6, the pump presents an intake port 10 and an exhaust port 12, respectively. A iiuid passage 14 is provided in the section 6 and establishes communication between the intake port 10 and the chamber 8. An additional uid passage 16 is provided to establish communication between the chamber 8 and the exhaust port 12.

The section 6 is additionally crossed drilled at 18 ICC and 20, respectively, said crossed drilled holes extending into the passages 14 and 16, respectively. The hole 18 is provided with an vinsert Y22 which may be secured to the section 6 by conventional cap screws 24, said insert 22 providing a seat for a one-way check valve 26 which is disposed in passage 14 intermediate the chamber 8 and intake port 10. The hole 20 is also provided with an insert 28, said insert being conventionally secured to the section 6 by cap screws 30. The insert 28 provides a seat for another one-way check valve 32, said check' valve 32 being located in the passage 16 intermediate the chamber 8 and exhaust port 12. It will be noted that the check valve 26 accommodates fluid flow from the intake port 10 tothe chamber 8 and prevents a reversal of said liuid flow, while the check Valve 32 accommodates fluid ow from the chamber 8 to the exhaust port 12 and prevents a reversal of fluid flow.

Section 6 is additionally provided with a crossed drilled aperture 36, said aperture being located centrally of the section and vertically aligned with the chamber 8. A guide bushing 38 is disposed in the drilled hole 36 at the lower end thereof and conventional packing glands 40 are disposed in the hole 37 immediately above the bushing 38. An insert 42 is provided to closey the upper end of the hole 36 and to retain the packing 40 and bushing 38 iixedly in position. The bushing 38, packing 40, and insert 42 are provided with centrally aligned holes which complementally receive a segment of an operating piston or plunger 44, the lower end of said plunger extending into the chamber 8. The plunger 44 can be seen to comprise a relatively large segment 46 and a smaller segment or tail rod 48 connected to the lower end of the segment 46 at a point disposed with the chamber 8. The Atail rod 48 extends downwardly Whereat it is received within a guide bushing 50, packing glands 52, and insert 54, the bushing, packing glands, and insert being ixedly disposed in an aperture in section 6 of the base 2. Thus it will be noted that the piston rod 44,is guided for linear movement within the base 2 at a pair of spaced points.

The upper end of the piston 44 is operatively connected to a linearly movable head 56, said head 56 being received within a'guiding frame 58 provided in the pump. The head 56 is pivotally connected to the lower end of a connecting rod 60 by means of a piston pin 62. The upper end of the rod 60 is conventionally split to form a lower section and cap which engage a throw 64 of a crank 66 as will be well understood by those skilled in the art. The crank arm 66 is, of course, operatively connected to a power source (not shown) whereby the throw 64 is eccentrically rotated about the center or rotational axis of the crank 66, thus imparting linear reciprocal movement to the head 56 and to the connected piston 44. Conventional lubricating devices 68 and 70 are provided to properly grease operating surfaces of the frame 58.

Directing attention to the piston 44 and particularly the segments 46 and 48, it will be seen that a working area 71 is provided on the end of the segment 46, said Working area being determined by the difference in cross sectional areas or sizes of the respective segments 46 and 48. The working area of the piston could reasonably be denominated a differential pressure area. It will be noted that through this construction, the working area 71 is considerably smaller than the cross section area of the relatively large section 46, thus providing a smaller working area whereby relatively high working pressures may be developed in the chamber 8 by the piston 44 while the piston and especially the segment 46, which is subjected to the operating load in compression,

is of relatively large cross section area and 'therebybetter able to withstand the axial loads applied thereto.

In operation, the throw 64 is rotated in the direction of the arrow d ue to rotation of the crank 66.' This in turn causes the head S6 to reciprocate vertically within the guiding means 5,8, and this reciprocating action is transmitted to the connected piston 44. The reciprocating action of the piston 44 on its upper stroke draws fluid from the intake port 10 past the check valve 26 and into the chamber 8, the check valve 32 preventing fluid ow in the passage 16 in the direction of' chamber 8. On the downward stroke of thepiston 44, the differential piston area 71 operatively works on the fluid in chamber 8 thereby increasing the pressure of said uid to the desired level and forcing the uid through passage 16 and outwardly through the exhaust port 12 past the one-way check valve 32. Theaction is repeated through each complete cycle of the piston 44 whereby a continuous volume of high pressure fluid is delivered tothe exhaust port.

Thus it will be seen that I have provided a reciprocating type pump arrangement capable of delivering high working pressures and one not subject to failure through buckling tendencies of similar pumps heretofore employed in the art. Additionally, the arrangement does not require extremely large or powerful power sources to deliver the desired working pressures.

I claim:

1. vA reciprocating high pressure plunger type pump comprising in combination, a base, a guide frame mounted in said base, a head slidably received in said guide frame, power means operatively connected to the head to reciprocate the head in said guide trame, a working chamber in said base, said chamber having an inlet and an exhaust port, a plunger secured to and movable with said head, said plunger having a body portion and a tail portion of smaller diameter than said body portion, the juncture of said portions, being disposed in said chamber to form a high pressure working area therein, guide means and packing glands in the base above said chamber slidably receiving said body portion, and guide means and packing glands in the base below said chamber slidably receiving said tail portion.

2. A reciprocating high pressure plunger type pump according to claim l, and including one-way check valves in respective ports accommodating flow of fluid through said chamber in a common direction.

3. In a reciprocating high pressure plunger type pump, a base, a guide frame mounted in said base, a head slidably received in said guide frame, power means operatively connected to the head lto reciprocate the head in said guide frame, a working chamber in said base, a plunger secured to and movable with said head, said plunger having a body portion and a tail portion of smaller diameter than said body portion thereby defining a high pressure working area, guide means and packing glands carried by said base and slidably receiving said body portion and other guide means and packing glands `carried by said base and slidably receiving said tail portion.

4. A reciprocating plunger type pump operable to develop high working pressures, said pump comprising a base, a chamber in the base, an intake port in said base, a check valve operatively connecting said chamber and said port and accommodating flow of fluid only from the port to the chamber, an exhaust port in said base, a check valve Yopaeratrfsly connecting said chamber and said exhaust port and accommodating how of fluid only from the chamber to the exhaust port, a guide frame carried in said base, a reciprocating head slidably received in said guide frame, power means operatively connected to said head, a plunger operatively secured to said head and guidably received in an aperture in the base, said plunger extending into the chamber, an end on the plunger, said end being disposed in the chamber, a tail rod xedly connected to the plunger centrally of the end, said rod being smaller than the end of said plunger, said rod being guidably received in another aperture in the base, and packing glands carried by the base and operatively associated with said plunger and said rod to prevent the llow of high` pressure uid past Vsaid plunger and said rod, respectively.

References Cited in the file ot" this patent UNITED STATES PATENTS 364,258 Keating June 7, 1887 1,724,156 Winton Aug. 13, 1929 2,733,664-l saa1frank Feb. 7, 1956 l FOREIGN PATENTS 117,212 switzerland oct. 16, 192s" 506,210 Belgium Oct. 3l, 1951

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