US3043235A - Reciprocating pump - Google Patents

Description

y 2 R. s. c. SMITH RECIPROCATING PUMP Filed Sept. 18, 1959 hmmmamm V I INVENT R m; S. c.

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ATTORNE Y United States Patent 3,943,235 REQEPROCA'HNG PUD/l1 Robert Sidney Claridge Eirnith, Chislehurst, Kent, England, assignor to John Selby Hillyer, Kent, England Filed Sept. 18, 1959, Ser. No. 848,867 8 Claims. (til. 103-492) The present invention relates to reciprocating pumps of the kind adapted to deliver fluid in both directions of relative axial movement of the inner and outer members with respect to one another.

It is an object of the present invention to provide practical means of constructing a pumping element so as to enable an appreciably small effective annular area to be presented against the fluid under delivery in each direction of axial movement of the inner and outer mating members with respect to each other.

It is also an object of the invention to provide a pump which will deliver fluid under substantially high Working pressures in each direction of relative axial movement of the inner and outer members with respect to each other without requiring more than small operating forces.

It is a further object of the invention to provide a pumping element in which substantially the whole of the internal delivery space can be swept clear of fluid in each direction at the termination of each full axial movement between the inner and outer members.

It is yet a further object of the invention to provide improved means of supporting the internal members of such pumps against excessive side or radially applied loads reacting at right angles to the pumping element.

A preferred constructional embodiment of this invention, as applied to a small hand pump, will now be described by way of example with reference to the accompanying drawing wln'ch is a view partly in longitudinal cross-section and partly in side elevation of such a hand pump.

The pump illustrated in the drawing has an inner assembly comprising two lengths of brass tube 11, 12 of slightly different external diameters which are coaxially interconnected by a junction piece 13, 14. The part 13 of the junction piece, which has a plain cylindrical outer surface of slightly smaller external diameter than the brass tube 12, is inserted a short distance into the bore of the tube 11 and is secured therein by soldering. The other part 14 of the junction piece is externally screw-threaded, screwed into the tube 12 and secured by a lock nut 15. The part 13 of the junction piece provides an annular gap between the cylindrical surfaces of the tube portions 11 and '12. A central axial bore 16 extends through the part14 of the junction piece and through the part 13 thereof as far as the position where the part 13 enters the tube 11. At this position, it has a closed end 17. Immediately adjacent the end of the tube 11 in which the part 13 is soldered, radial bores 18 are drilled in the part 13 so as to interconnect the closed end of the bore 16 with the outside of the part 13.

At the end remote fro-m the tube 12, the tube 111 is provided with a short extension piece 19 carrying a handle (not shown) at its outer end and formed with a flange 21 on the end thereof adjoining the tube 11.

The end of the tube 12 remote from the tube 11 is externally screw-threaded at 22 to receive a stop nut 23 and an associated lock nut 24. The screw-threaded part 22 may also serve for the attachment of a spraying nozzl (not shown).

The inner assembly comprising the tubes 11, 12 .is housed within an outer assembly comprising a brass tube 25 which is slightly shorter than either the tube 11 or the tube 12 and has an internal diameter slightly greater than the external diameter of either of these last-mentioned 3,43,235 Patented Jul in, race ice washers 37, 38, a neck ring 39 and a gland ring 41 is accommodated within the housing 27. The O-rings 3-1 and 36 co-operate respectively 'with the outer surfaces of the brass tubes 11 and 12.

A radial inlet port 42 is drilled in the housing 27 immediately adjacent the corresponding end of the tube 25. Brazed to the housing 27 so that it'coaxially surrounds the outer end of the port 42 is an internally screw-threaded socket 43, into which is screwed a valve housing 44 having an extension 45 for'connection to a flexible hose (not shown). Within the valve housing 44 is arranged a nonreturn valve consisting of a ball 45 which is urged towards a seating 47 by a spring 48. An axial bore 49 drilled through the extension 45 opens through the middle of the seating 47.

A baffle, in the form of a tubular member 51 of nylon formed with a circumferential groove to accommodate a sealing ring 52 cooperating with the bore ofthe brass tube 25, surrounds the part 13 of the junction piece 13, 14 and is capable of limited axial movement within the gap between end surfaces of the tube 11 and the lock 'nut 15. An appreciable annular clearance is provided between the external cylindrical surface of the part 13 and the internal surface of the member 51. At the end nearer the tube 11 the member 51 has its inner edge charnfered as at 53. Radial grooves 54 are also form edin the member 51 at this end to prevent it from seating against .the

end of the tube 11. The other end 55 of the member 51 is adapted to co-operate with the end 56 of the lock nut 15, so that, when the member 51 is pressed against the lock back, i.e. to the left as seen in FIG. 1, the baffle member 51 is displaced so that its surface 55 seals against the surface 5 6 on the lock nut 15 with the result that fluid is drawn in through the bore 4? and past the valve 46 into the chamber 57. Then, on reversal of the direction of movement of the inner assembly, the valve 46 closes and the battle member 51 is displaced to disengage the surfaces 55, 56

so that fluid is transferred from the chamber 57 to the chamber 58 between the surfaces 55, 56, through the annular clearance between the bafile member 51 and the part 13 and through the radial grooves 54. Since the volume of the chamber 57 is reduced more rapidly than that of the chamber 58 is increased, fluid will also be discharged through the bores 18 into the bore 16. On further reversal, the surfaces 55, 56 are once again sealed together and, while fluid is drawn into the chamber 57 past the valve 46, fluid is also transferred from the chamber 58 into the bore 16 via the radial grooves 54 and the radial bores 18. It will be observed that while suction occurs in only one direction of movement, i.e. when the inner assembly is moved to the left in the drawing, delivery through the bore 16 occurs during both directions of movement.

The length of stroke of the pump is limited at one end by the nut 23 abutting against the gland nut 29 and at the other end by the flange 21 abutting against the gland nut 28. The positions of the nut 23 and the flange 21 relative to the baffle member 51 are such that the chambers 57 and 58 are almost completely emptied during alternate strokes of the pump.

The sizes of the respective working surfaces may be so arranged that, while the quantity delivered may be substana the two members.

aocaass tially equal in both directions of motion of the inner assembly with respect to the oute r assembly, it may, also be kept suificiently low to enable very high pressures to be developed at the delivery connection, i.e. in the part 22, Without itbeing necessary to exert more than relatively small forces to operate the pump. Thus, for example, the

internal diameter offthe tube 25 may be 1.001 inch, the external diameter of the tube 11 1.080 inch and that of the tube .999 inch. a T

Van'ousmodifications may be made in the pump described above without exceeding the scope of the present inventionas defined in the appended claims. Thus, for

example, two Working surfaces of diiferent diameter may be provided on the outer member and a working surface of uniform diameter on the inner member. In this case the bafiie may -be located in an interruption between the working surfaces of the outer member and arranged to seal against the working surface of the inner memberyand the sealing means may be carried by the inner member and arranged to seal against the working surfaces-of the outer member. Furthermore, the non-return valve for the transfer of fluid from the annular space of larger radial thickness to that'of smaller radial thickness, instead of being constituted by an end surface of the baflie whichis engaged with and disengaged from a seatingaccordingto the axial position of the baflie, may be constituted by a separate non-return valve incorporatedin the baflie. Yet;

further alternatively the baflie maybe constructed so as to j prevent the flow of fluid pastthe baffle in either direction in which case a non-return valve is provided to act in vconjunction with the baflie but may be located eitherof The 'fluidinlet and outlet connections may be located according to convenience either both' in the first member or both in the second member or alternativelywith the tively with the inlet in the second member and theoutlet connection in the first member irrespective in each case I of the relative disposition of the two members as to whetherthe first be within the second or the second be the first, provided always that the inlet connect 4 a p connection connectedfor the discharge of fluid from the annular space of smaller radial thickness; a

2. .A reciprocating pump asjclaimed in claim 1, wherein the baffle is retained in a position between the working surfaces of said other member.

3. A reciprocating pump as claimed in claim l, wherein the working surface'of said one member is of shorter length than the working surfaces of said other member.

4. A reciprocating pump as claimed in claim 1, and further comprising bearings for slidably supporting said other member, said bearings being combined with the sealing means carried by said one member. I

5. A reciprocating pump comprising two elongated members arranged for relative sliding movement one within the other, one of said members having a cylindrical working surface of uniform diameter and the other of said members having two coaxial Working surfaces of different diameters. to one another and to the working surface of baflie located between the two Working surfaces of said other member and forming a seal against the working surface of said one member, said baflie being free to move axiallyv through a limited distance, a non-return inlet valve connected for the supply of fluid to the annular space of larger radial thickness, a non-return delivery valve arranged to permit transfer of fluid past said baffle in the direction from the annular" space of larger radial thickness to that of smaller radial thickness, said non-return delivery valve comprising an end surface of said baffle facing the annular. space of larger radial thickness and a seating surface carried "by said other member and arranged, when the baflle is in its end position near the annular space of larger radial thickness, to be engaged by the said end surface of the battle and thereby'to seal this last i mentioned space from the space of smaller radial thickwith the annular chamber bounded by thesurfaces'having the greater diametral dimensional difference and the outlet connect with the annular chamber bounded by the surfaces having the smaller diametral dimensional difference.

According to the invention the pump may beprovided ,4 with a non-return valve at the fluid inlet, This valve may be located either in the first orsecond member irrespective of their relative dispositions.

- In the caseof power operated pumps a plurality of elearrangements.

I claim:

1. A reciprocating pump comprising two elongated members arranged for relative sliding movement one within the. other, one of said members having a cylindrical 'working surface of uniform diameter and the other of said ments may be employed to provide either radial or axial v smaller radial thickness respectively are formed between 7 the working surfaces of said one member and said other member, sealing means secured to said one member at opposite ends of its working surface and co-operating respectively with, the two working surfaces of said other member to sealthe outer ends of said annular spaces, a baflie located between the two working surfaces of said other member and forming a seal against the working surface of said one member, a non-return inlet valve connected for the supply of fluid to the annular space of larger radial thickness, valve means form-ing a non-return delivery valve arranged to permit transfer of fluid past said baffle in the direction from the 'annular space of largerradial thickness to that of smaller radial thickness, and an outlet ness, and an outlet connection connected for the discharge 7 of fluid from the annular space of smaller radial thickness.

6. A reciprocating pump comprising an outer clongated tubular member having an internal cylindrical working surface of uniform diameter, an inner elongated member having'twoexternal cylindrical working surfaces arranged coaxially on dilferentlinear portions thereof, the diameters of said two external Working surfaces being fractionally different from one another and the larger of them being fractionally smaller than the diameter of .the working surface of the outer tubular member so' that annular spaces of larger and smaller radial thickness respectively are formed between the working surfaces of said inner and outer members, sealing .means secured to said outer tubular'member at opposite ends of its working surface and co-operating fer of fluid past said *baflle from the annular space of the outlet connection emerges from the pump at the end of the inner member remote from the working surface of larger diameter and includes a passage for-med axially through the inner member to a point. beyond said baffle 5 and is connected to the annular space of smaller radial thickness.

8. A reciprocating pump as claimed in claim 6, Wherein the inner member comprises two tubes on which its two working surfaces are provided, a junction piece interconnecting said two tubes in end-to-end relationship and providing an annular 'gap between them, the baflie being arranged so that it loosely surrounds the junction piece within said gap and is capable of limited axial movement, so that, in its end position nearer the smaller of the two tubes, its end face engages a valve seating sur- 6 face on the smaller tube to seal the space of larger radial thickness from the space of smaller radial thickness and so that in its other end position fluid can pass from the space of larger radial thickness and through the clearance between the baffle and the junction piece to the space of smaller radial thickness.

References Cited in the file of this patent UNITED STATES PATENTS Wise s July 6, 1954

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