US2491607A - Alternating piston pump or prime mover - Google Patents

Description

Dec. 20, 1949 J. DOMMISSE ET AL ALTERNATING PISTON PUMP 0R PRIME MOVER Filed March 22, 1946 INVENT RS Jan Dommnssc and EH: ROdQFICK MGJL'HQSon Then HCt00'h? 1 Patented Dec. 20, 1949 ALTERNATING PISTON PUMP OR PRIME MOVER Jan Dommisse and Eric Roderick Matheson, Johannesburg, Transvaal, Union of South Africa Application March 22, 1946, Serial No. 656,290

8 Claims. (01. 103-129) This invention relates to a rotary device or engine which is suitable for use as a pump or prime mover.

One object of this invention is to provide such device which combines the advantage of positive action of the same kind as is obtained with reciprocating engines, with the advantages arising from the use of purely rotary movement.

Another object is to provide a rotary device or engine of simple and sturdy construction.

A further object of this invention is to provide a rotary device or engine which can be easily and quickly assembled and dismantled.

A further object of this invention is to provide such device or engine which can operate over long periods without appreciable diminution of capacity due to wear, and in which those rotary parts which are mainly exposed to wear can be easily replaced.

A further object of this invention is to provide a pump of simple and sturdy construction and high efficiency, which needs little or no supervision and is thus particularly suitable for use as a borehole or deep well pump.

In one aspect of this invention, a rotary device suitable for use as a pump or prime mover, comprises two co-axial cylinders, at least two pistons arranged for rotation in the annular space between said cylinders and about the axis of said cylinders, and shaped to divide the annular space between said cylinders into compartments; and means for so rotating said pistons as to vary, during each complete revolution, the space of each such compartment from a maximum to. a minimum and: back again to a maximum. When "this device is to be used as a pump, means are provided for introducing fluid into each of said chambers when the volume of said chamber is being increased to its maximum, and for releasing fluid therefrom while the volume of the respectiv chamber is being decreased to its minimum. J-

In one form of this invention a device suitable for use as a .pump or prime'mover comprises a cylinder, a plurality of. pistons within said cylinder and constrained forimovement along a' path which is co-axial with, said cylinder, adriving member the axis of which is parallel with the axis of said cylinder and offset from said cylinder axis, and movable linksconnecting each of said pistons to said driving member whereby continuousrotation of said driving member at constant angular speedbrings aboutrotation of said pistons combined witha relativemovement of said pistons towardsand away from one another. 65

In this specification and the claims attached thereto the term piston is intended to include vanes, blades, and other equivalent means.

In a preferred form, a device according to this invention comprises a materially tubular casing providing an inlet and an outlet; a cylinder within said casing, said cylinder being closed at its one end by a plate which is formed with a hole that provides the sole communication between the inside of the cylinder and said casing inlet; a bearing, at the other end of the cylinder, for a driving means, said bearing being eccentric with respect to said cylinder; driving means seated in said bearing and adapted to be connected to a driving shaft; an inner cylinder within and co-axial with the first said cylinder; at least two pistons which divide the annular space between said two fcylinders into compartments and which are arranged for orbital movement about said inner cylinder; connecting means between each of said pistons and said driving means; and an outlet port in the wall of the first said cylinder connected to said casing outlet. Preferably the casing is integral with said cylinder, the axis of said casing being parallel to the axis of said cylinder but ofiset from said cylinder axis, said casin extending at both its ends beyond the open ends of said cylinder and being formed with recesses which are co-axial with said casing and which provide seats for said plate, at the one end of said cylinder, and for said hearing at the other endof said cylinder; said bearin and said plate being held on said seats by screw-caps which are screwed into the ends of said casing and which provide respectively the inlet means and the outlet means-of said casing.

The driving means may comprise two members which are constrained for rotation with one another but which have axially a limited freedom of movement with respect to one another; one of'said members being adapted to 'be connected to a driving shaft whilst the other member has attached thereto the aforesaid connecting means.

Said connecting imeans preferably comprises a pin on the piston which is parallel with the axis of said cylinders, a pin extending from the driving means and parallel with the first said pin, and a link pivotally connected to each of said pins.

The pistons are formed to make close contact with the inside of the one cylinder as well as with the outside of the inner cylinder, whilst being freely rotatablefabout said inner cylinder. For ,this, purpose, each piston preferably com.

prises an outer member formed with an arcuate surface of the same diameter as that of the inside of said first cylinder, an inner member formed with an arcuate surface of the same diameter as that of the outside of said inner cylinder, the two arcuate surfaces being concentric with one another, a radial member connecting said outer member to said inner member, and resilient sealing means extending in the axial direction along materially the whole length of the inner arcuate surfaces and secured in recesses provided in said surfaces. Preferably, one or more grooves may be provided extending in the axial direction along materially the whole length of the outer arcuate surfaces.

Pistons of the kind specified in the last preceding paragraph are comprised in and form part of this invention.

An example of this invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a sectional elevation of a deep-well pump on line 1-1 of Fig. 2.

Fig. 2 is a section, on line II--II of Fig. 1.

Fig. 3 is a plan of the pump with its upper cap removed and partly sectioned on line IIIIII of Fig. 1.

With reference to the figures, I indicates the tubular pump casing which has a cylinder 2 formed integral therewith. The casing is of generally cylindrical form and has its axis (see Fig. 2) parallel with, but offset from the axis 0 of said cylinder 2. The casing I is threaded at 3 to receive an inlet cap 4 which latter is threaded at 5 for connection with a suction pipe or a strainer, or with a footvalve and strainer or the like. The casing I is further threaded at 6 to receive an outlet cap 'I which has its outlet end 8 threaded at 9 for connection with the rising main conveying the water delivered by the pump to the surface.

The cylinder 2 is closed at its inlet end by a plate II) the spigoted end I I of which fits into said inlet end and which provides the inlet port I2; and is closed at its other end by a bearing IS the spigoted end I4 of which fits into said other end of the cylinder 2. At its side the cylinder 2 is formed with an outlet port I5 which is connected by ports I6 and IT with the pump outlet 8.

The plate It and the bearing I3 are seated in recesses I8 and I9 in the casing which are concentric with the casing but eccentric with respect to said cylinder 2; and are securely held in position by said inlet cap 4 and outlet cap 1 respectively. 20, 2|, 22 and 23 are packing rings arranged to provide fluid tight joints at the ends of the casing I and cylinder 2.

Housed in the bearing I3 are the driving member 24 and the transmitting member 25 which are constrained to rotate together as by pins 26 which latter are fixed into bosses 21 of member 24 on the one hand, and slidably project into suitably shaped recesses 28 in the flanged part 29 of the second member 25 on the other hand; and which leave the members 24 and 25 free for axial movement relatively to one another...

The transmitting member 25 is adapted to be connected to a driving shaft 36,. and has for this purpose its end 3|, which projects out of the bearing, recessed and screw-threaded at 32 to receivethe screw-threaded end 33 of said shaft. The driving shaft is secured to the member 25 as by a lock-nut 34; and a shield 35 is arranged on said projecting end 3I ofv member 25 andis secured thereto as by said lock-nut 34. 'Said shield 35 loosely encloses the boss 36 of the beariii) ing I3.

ing I3 and prevents entry into the bearing-of sediment, such as may settle out from the water column in the rising main while the pump is at rest.

The transmitting member 25 is free to move axially between a position in which the upper face at of its flanged portion 29 bears against the surface 38 of the bearing I3, and a second position, in which the shield 35 bears against the boss 36 of the bearing I3. The respective parts are so dimensioned that the transmitting member 25 has sufficient freedom of axial movement to compensate for expansion and contraction in the drive shafting and thus relieves driving member 24 from strain caused by expansion or contraction in said shafting.

The driving member 24 has is lower face resting on the pistons 39, 40, 4| flush with the spigotted-face I 4 of the bearing I3 and has its upper face located by the inner surface 38 of the bear- Said driving member is provided with three equally spaced bosses 42 in each of which is secured a driving pin 43 which extends into the cylinder 2 and is connectedto one of said pistons.

Located in the cylinder 2 is the inner cylindrical member 44 which reaches from the plate ID to the driving member 24 and is fitted with renewable top and bottom caps 45 and 46. Said inner cylindrical member 44 is free for relative rota, -tional movement with respect to said cylinder 2, plate I6, and driving member 24, and is held substantially co-axial with said cylinder 2 by said pistons but is at the same time free to move radially to the extent of the clearances between the cylindrical member 44 and the pistons and between the pistons and the cylinder 2 Whilst, in turn, restraining said pistons for orbital movement along a path which is concentric with said cylinder 2.

The pistons 39, 46 and M are spaced about the inner cylindrical member 44 and are arranged for relative sliding movement with respect to cylinder 2, inner cylindrical member 44, plate ill and bearing I3. The clearances between the pistons and said plate In and bearing I3 are made small in order to reduce slippage of fluid past the pistons. For the same purpose, the outer faces 41 of the pistons are made in cross-section of arcuate shape of the same diameter as that of the inner wall 48 of the cylinder .2, and are provided with grooves 49 extending, in the axial direction, along the whole height of the pistons. In operation, centrifugal force in conjunction with the forces transmitted by the links 58 tends to maintain the outer faces of the pistons in close contact with the cylinder wall 48 and thus reduces slippage between them. Similarly, the inner face 50- of each piston is formed suitably to reduce slippage between itself and the, inner cylindrical member 44. In the example, each such face is, in cross-section, of arcuate shape of the same diameter as that of the outside of said inner cylindrical member 44. Further, by virtue 'of the freely movable cylin .drical member 44, fluid pressure in the chambers subject to the outlet pressure of the pump causes the cylindrical member 44 to bear against the pistons enclosing the chambers subject to the inlet pressure of the pump, said pistons in turn bearing against the cylinder 2-; thus, an effective seal is maintained between the chambers under high fluid pressure and the chambers under low fluid pressure which will compensate for such radial wear as may result from'normal operation.

'In' addition; each "inner piston face is formed with a groove in which is secured a packing strip In the example, each piston comprises an outer portion 52 which provides the outer face 41, an inner portion 53 which is peripherally substantially shorter than said outer portion 52 and which provides theinner face 50, and an intermediate portion 54 which connects said two portions 52 and 53 to one another. Said three portions 52, 53 and 54 will be in most cases integral with one another, and are so illustrated in the drawings.

Each piston is further provided with two bosses 55, 55 in which is secured a piston pin 56 which is held immovable with respect to the piston as by a grub screw (not shown) which engages a recess 51 in the pin. A Each piston pin is connected to its corresponding driving pin by a link 58 which is arranged for pivotal movement with respect to both its piston pin and itsdriving pin.

In use, the pump assembly is suspended in the borehole from the rising main which is screwed into the top cap 1. The motive power is pro- ,vided on thesurface of the borehole by a suitable prime mover and is transmitted by drive shafting, preferably located inside the rising main, to the driving shaft of the pump assembly. The rotary movement of the driving shaft 30 is transmitted by the transmission member 25 to the driving member 24. Rotation of said driving member 24 causes the driving pins 43 to move in a circular path about the casing axis 0. The rotary movement of the driving pins is transmitted through the links 58 to the pistons 39,

40 and-4i and causes the latter to rotate in their orbital path about the cylinder axis 0 As a result of the eccentricity of the path'of the drivin pins with respect to the orbit of the pistons, rotary movement of said driving pins at constant angular velocity causes the pistons to accelerate during one part of each orbital movement and to decelerate during another part of said movement, each piston being accelerated relative to the next preceding piston during one part of the orbital movement and decelerated relative thereto during another part of said movement.

When the leading piston is being accelerated relative to the trailing piston the chamber defined between the oo-acting surfaces of the two pistons expands and increases its volume. When, on the other hand, the leading piston is being decelerated relative to the trailing piston, the distance between the co-acting surfaces of the two pistons e decreases, and the chamber defined between said surfaces contracts and decreases in volume accordingly.

Durin each complete orbital movement of the pistons each of the three chambers 59, 60, 6| decreases from a maximum to a minimum and increases again to said maximum.

In Figure 2, the chamber BI is shown to be at a minimum, whilst the chamber 60 is about to increase to its maximum.

The arrangement is such that each chamber is in communication with the inlet port 12 during that part of the cycle during which said chamber is increasing to its maximum, and that said chamber opens to the outlet port during that part of the cycle during which the volume of the chamber is being decreased to a minimum. In the example, the trailing piston closes the suction port 12 when the chamber volume approaches a maximum, and immediately afterwards the lead- 6 ing piston uncovers the outlet port 15. The chamher is now in direct communication with the casing outlet 8, through the outlet port 15, andthe apertures I6 and I1. While the chamber. is so connected to the casing outlet, the volume of the chamber is decreased from a maximum to a minimum, and a corresponding portion of the water, previously sucked into the chamber from inlet port I2, is forced out of the chamber by the contracting movement of the latter. When the chamber volume approaches a minimum, the trailing piston covers the outlet port I5 whilst immediately afterwards, the leading piston uncovers the suction port l2, whereupon the cycle of operation begins anew.

We claim:

1. A rotary piston machine suitable for use as'a pump or prime mover, comprising a materially tubular casing providing an inlet and an outlet; 2. cylinder within said. casing, said cylinder being closed at its one end by a plate which is formed with a hole that provides the sole com: munication between the inside of the cylinder and said casing inlet; a bearing, at the other end of the'cylinder, for a driving means, said bearing being eccentric with respect to said cylinder; driving means seated in said bearing and adapted to be connected to a driving shaft; a freely floating cylindrical member within said cylinder; at least two pistons which are arranged to hold said cylindrical member materially co-axially with said cylinder and which divide the annular space between said cylinder and said cylindrical member into compartments and which are, in turn, constrained by said cylindrical member for a movement co-axial with said cylinder; con necting means between each of said pistons and said driving means; and an outlet port in the wall of said cylinder connected to said casing outlet.

2. The machine claimed in claim 1, in which the driving means comprises a first member which is adapted to be connected to a driving shaft and a second member to which said connecting means are attached; said first member having a limited amount of freedom of axial movement relatively to said second member but being constrained for rotary movement co-axlal with said second member.

3. The machine claimed in claim 1, in which the casing is integral with said cylinder, the axis of said casing being parallel to the axis of said cylinder but offset from said cylinder axis, said casing extending at both its ends beyond the open ends of said cylinder and being formed with recesses which are co-axial with said casing and which provide seats for said plate, at the one end of said cylinder, and for said bearing at the other end of said cylinder.

4. The machine claimed in claim 1, in which the casing is integral with said cylinder, the axis of said casing being parallel to the axis of said cylinder but offset from said cylinder axis, said casing extending at both its ends beyond the open ends of said cylinder and being formed with're cesses which are co-axial with said casing and which provide seats for said plate, at the one end of said cylinder, and for said bearing at the other end of said cylinder; said bearing and said plate being held on said seats by screw-caps which are screwed into the ends of said casing and which provide respectively the outlet means and the inlet means of said casing.

5. The pump claimed in claim 1 in which the driving means comprises a first member which is connected to a driving shaft and a second member to which means are attached which connect said second member to the pump pistons; said first member being axially movable with respect to said second member, but being constrained for rotary movement co-axial with said second member; and a shield which is interposed between said first member and said driving shaft; said shield being arranged to protect the bearing of said first member against sediment and to limit unidirectionally the freedom of axial movement of said first member, relatively to said second member.

6. A pump comprising a cylinder; a cylindrical member within said cylinder and suitable to be held materially co-axially with said cylinder, said cylindrical member being freely movable radially with respect to said cylinder; at least two pistons arranged for rotation in the annular space between said cylinder and said cylindrical member, said pistons being formed suitably to hold said cylindrical member materially co-axialiy with said cylinder and being shaped to divide said annular space into compartments; a plurality of resilient sealing means in the face of each piston adjoining said cylinder, each such means extending in the axial direction along materially the whole length of the piston; and means for so rotating the pistons as to vary, during each complete revolution, the space of each compartment from a maximum to a minimum and back again to a maximum.

7. A rotary piston pump, comprising a materially tubular casing providing an inlet and an outlet, said inlet and said outlet being arranged at opposite ends of said casing and being materially co-axial with the latter; a cylinder within said casing, said cylinder being closed at its one end by a plate which is formed with a hole that provides the sole communication between the inside of the cylinder and said casing inlet; a bearing at the other end of the cylinder for a driving means, said bearing being eccentric with respect to said cylinder; at least two rotary pistons within said cylinder; driving means seated in said bearing and arranged to accelerate each piston positively during one part of each complete orbital movement of such piston and to accelcrate said piston negatively during another part of said movement, said driving means comprising a first member which is connected to a driving shaft and a second member to which means are attached which connect said second member to the pistons, said first member being axially movable with respect to said second member but being constrained for rotary movement co-axial with said second member, and a shield interposed between said first member and said driving shaft, said shield being arranged to protect the bearing of said first member against sediment and to limit unidirectionally the freedom of axial movement of said first member relative to said second member, a passage extending between said casing and the outside wall of said cylinder and materially parallel with the latter; and an outlet port in the wall of said cylinder, said outletport being connected to said casing outlet by said passage.

8. A rotary piston pump, according to claim 7, in which the first member of the driving means is axially movable with respect to the second'member but constrained for rotary movement coaxial with such second member by pins which are secured to one of said members and which project into recesses in the other member.

JAN DOMMISSE. ERIC RODERICK MATHESON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 664,938 Fong Jan. 1, 1901 665,390 Brown Jan. 1, 1901 727,171 Mayer May 5, 1903 2,095,987 Kratzer Oct. 19, 1937 2,394,337 Sobek Feb. 5, 1946 FOREIGN PATENTS Number Country Date 1,732 Great Britain Apr. 21, 1881 159,250 Great Britain Feb. 22, 1921 27,126 France Jan. 9, 1924 358,081 Great Britain g Oct. 28, 1931

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