GB2160933A

GB2160933A - Fluid pumping apparatus

Info

Publication number: GB2160933A
Application number: GB08514086A
Authority: GB
Inventors: David Macmillan
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-06-09
Filing date: 1985-06-04
Publication date: 1986-01-02
Also published as: GB8514086D0; GB8414788D0

Abstract

A fluid pumping apparatus for immersion in the fluid to be pumped has a piston arrangement (7) reciprocated within the housing (1) by means of an hydraulic ram (40), the piston arrangement including piston valve units (10, 11) which allow fluid to pass into pumping spaces defined between a stationary partition (6) and each respective valve unit when each space is expanding. On contraction of said spaces fluid is delivered to a common outlet connected through one-way valves to each side of the partition. Each valve unit includes a valve seating member (14) which is allowed to undergo limited displacement along the operational direction of movement or a region (24) thereof can undergo such displacement relative to the remainder (23) of the piston arrangement (7). <IMAGE>

Description

SPECIFICATION Fluid pumping apparatus The present invention relates to fluid pumping apparatus and, in particular to pumping apparatus for pumping slurries such as, for example, animal waste.

It is a common practice to feed animal waste from animal houses into a waste pit from which it is subsequently removed by transfer to a tanker or other suitable vehicle for subsequent use as manure for spreading on land. Because of the highly fluid characteristics of such animal wastes it is the usual practice to effect the transfer of the waste from the pit to the tanker by means of a slurry pumping pump.

It is an object of the present invention to provide a slurry or like fluid pump which is of a relatively simple and robust construction, and which is readily operable from the power take-off of a tractor or the like having power take-off facilities.

STATEMENTS OF INVENTION Broadly, according to the invention there is provided a fluid pump apparatus including a piston arrangement for reciprocation lengthwise of a pump housing to effect a pumping action, wherein the piston arrangement includes a first fluid sealing means of which at least a predetermined region thereof is allowed to undergo, with respect to the remainder of the piston arrangment, a limited amount of displacement to allow admission of fluid to be pumped.

Preferably, the pumping apparatus is double acting and the piston arrangement incorporates first and second valve units with each such unit including a sealing means which is allowed to undergo said limited displacement.

Preferably, each valve unit incorporates; a plate member adapted for connection to means for reciprocating the plate member with respect to the housing; an annular sealing element having a generally L-shaped cross section providing a first part for co-operation with at least the marginal or peripheral regions of the associated plate member and a second part for effecting sealing co-operation with the wall of the pump housing; and means for retaining the sealing element in a predetermined position relative to the plate member whilst allowing movement of the sealing element relative to the remainder of the valve unit during pumping operation.

Preferably, the retaining means includes a plurality of retaining elements spaced around the plate member and arranged to provide a portion radially directed of the plate member and off-set therefrom for engagement with the sealing element first part on the face thereof remote from the plate member whilst allowing relative movement between the sealing element and the plate member.

Conveniently, the plate member is provided on the the face thereof remote from the sealing element with second radially directed elements which are such as to prevent the sealing element from undesired bodily movement towards the remote side of the plate member.

In a further arrangement the plate member includes an elongate central portion and two outer portions which are pivotally connected to the central portion, and wherein the sealing member has a first part secured to the peripheral regions of the three pivotally connected portions and a second part inclined to the first part for co-opertion with the wall of the pump housing, whereby in operation the outer portions are enabled to pivot with respect to the inner portion either to allow admission of fluid to be pumped into the housing or to retain the admitted fluid within the housing to enable the pumping thereof to fluid discharge means, therebeing stop means for limiting the extent of pivoting in either direction.

Conveniently, the sealing means can be produced by splitting a wheel tyre along the central plane thereof into two sections whereby for each such section the wall structure of the tyre provides that part that cooperates with the housing wall.

For a better understanding of the invention and to show how to carry the same into effect reference will now be made to the accompanying drawings in which: Figure 1 is a schematic view of a first embodiment of pumping apparatus incorporating the features of the invention; Figure 2 is a part sectional plan view of the pumping apparatus of figure 1 and illustrating two forms of a valve unit for the pumping apparatus; Figure 3 is a part side view of the pumping apparatus as shown in Figures 1 and 2 only one form of valve unit being shown; Figure 4 is a sectional view to an enlarged scale of a detail of one of the valve units of Figure 3; Figure 5 is a face view to an enlarged scale of the second form of the valve unit; Figure 6 is a side elevation of the valve unit of Figure 5; Figure 7 is a plan elevation of the valve unit of Figures 5 and 6; and Figure 8 is a schematic sectional view of a second embodiment of the pumping apparatus of the invention.

The embodiment of the invention shown in Figures 1 to 4 includes a cylindrical housing 1 whose main dimensions can be 1020 millimetres in length and 500 millimetres in diameter. The housing 1 is supported from two side rails 2 by way of brackets 3 located one adjacent to each end of a rail. The rails are, in turn, mounted upon support legs 4 such that the lowermost regions of the housing are spaced away from the ground. The rails 2 are of a hollow construction and are open at their ends 5 for the reasons to be discussed hereinafter. A dividing wall 6 separates the interior of the housing into two sections 1A and 1 B, the wall being perpendicular to the longitudinal axis of the housing.

A piston valve arrangement 7 is mounted to be operationally slidable with in the housing 1. The arrangement 7 includes a shaft 8 which is journalled in a bearing 9 at the centre of the wall 6, a first valve unit 10 and a second valve unit 11, the units being mounted from the shaft 8, whereby the valve units are operationally displaced relative to the housing by axial reciprocation of the shaft 8.

In practice, the valve units 10 and 11 are of a similar construction. However, for convenience of illustration and description the Figure 2 illustrates two different constructions for the valve units 10 and 11. The valve unit 10 as shown in Figures 2,3 and 4 will be considered first, and the valve unit of Figures 2,5,6 and 7 will be considered thereafter. The valve unit 10 includes a circular plate 1 3 secured to the shaft 8, and having an outside diameter of 432 millimetres and a wall thickness of 5 millimetres. With a housing of the dimensions above given the length of the shaft can be 610 millimetres and its diameter 35 millimetres.A cup type sealing means 14 is carried by the plate 13; the seal including a flange part 1 5 which extends in face-to-face relationship with the plate 1 3 and a sealing part 1 6 which is intended to co-operate with the internal face 1 7 of the housing 1, and which extends lengthwise of the housing 1.

The valve 10 also includes a plurality of hook members 1 9 which serve to hold the otherwise loosely mounted cup seal 14 in operational co-operation with the associated plate 1 3. Furthermore, the plate 1 3 is provided with a plurality of radially directed spokes 20 on the face thereof remote from the cup seal associated therewith. The spokes can be conveniently welded in place. The spokes 20 are equiangularly spaced around the plate 1 3. The function of the spokes is to prevent the seal 14 from becoming trapped between the housing surface 1 7 and the plate 1 3 and also to prevent foriegn bodies from becoming trapped between the housing surface and the plate 13.

The shaping of the hook members 1 9 is such as to allow limited displacement between the plate and associated cup seal so that it is maintained in a position in which it is capable of operation as will be discussed hereinafter.

In practice, when a cup seal 14 is closely adjacent to its plate 1 3 it is in its sealing position, and when it is spaced away from its plate 1 3 the seal is in the position in which fluid can enter into the interior of the pump housing, the extent of displacement being set by the hooks 19.

In the second form of the valve unit 11 the associated circular plate 22 comprises three sections or portions, an elongate central portion 23, and two generally D-shaped outer portions 24, which are pivotally connected to the central portion. The central portion 23 is essentially a diametrical strip with parallel linear side edges 25 and part circular end edges 26. The D-shaped outer portions 24 have linear edges 27 and part circular outer edges 28. The outer portions are connected to the edges 25 of the central portion 22 by hinge arrangements 29 in such manner that the part circular edges 26 and 28 of the inner and outer portions combine to provide a complete circle. The central portion 23 is rigidly connected to the shaft 8. An annular cup like seal 30 is secured to the circular peripheral regions 26,28 of the three portions 23 and 24.The outer peripheral part 31 of the seal 30 is intended slidingly to co-operate with the internal surface 1 7 of the housing. The seal 30 can be formed from a half tyre as has been previously mentioned. The seal 30 bridges the join between the central and outer portions and serves to provide stiffnesss to the hinges 29. The D-shaped outer portions 24 in conjunction with the length of seal 30 attached thereto form flap type inlet valves for the pumping apparatus.

A stop flange or the like 31 is provided for limiting the extent of inward movement of the outer portions 24 which allows admission of fluid to be pumped. Additional stop means 32 are provided to prevent the pressures developed during pumping operation from over pivoting the outer portions 24 in either direction of the operational movements of the outer portions.

If it is thought necesary to provide support for the valve assembly 7 to avoid damaging the seals 14,30 a support framework can be provided. The figure 2 schematically illustates a support frame 33 which is arranged for slidable engagement with the above mentioned side rails 2. The frame 33 includes an end transverse rail 34, two outer rails 35 which slidably engage with the rails 2 by entering the adjacent open ends 5 thereof, and two inner rails 36 which connect the rail 34 to the associated plate 1 3 of a valve unit 10 or to the central portion 22 of a valve unit 11. The rails 36 are equidistantly spaced relative to the vertical axial plane of the longitudinal axis of the housing and also have longitudinal axes lying in the housing axial plane.

As can be seen the other ends of the rails 2 extend beyond the end of the housing to be bridged by a cross piece 38 at the extreme ends thereof and by an intermediate rail 39.

The rails serve to mount a hydraulic ram unit 40. The unit 40 is of the double acting type with the cylinder 41 thereof mounted between the rails 38 and 39 and with the rod 42 thereof coupled to the plate 1 3 or plate portion 22 of the valve unitlO or 11. In practice, the associated plate or plate portion is firmly secured to the shaft 8 and the combination with the ram unit rod 42. If desired,the connection of the shaft to the associated valve unit can incorporate a frame arrangement (not shown) which is at least in part supported by the rails 38,39 and 2.The purpose of this latter mentioned frame and the mounting frame 33 is to facilitate the support of the piston valve arrangement 7 and the associated ram 40 to take the weight of the valve units 10 and 11 and the associated ram unit 40 thereby to avoid crushing the seals 14,30 whilst at the same time effectively assisting in guiding the valve arrangement 7 throughout its operational movements.

The ram unit 40 is arranged to receive its operating power or fluid from a supply such as the power take-off of a tractor or a pump unit (not shown).

The pumped fluid outlet arrangements (Figure 3) for the pumping apparatus are provided at the top of the housing 1. The fluid outlet arrangement 45 includes an elongate aperture 46 located at the top of the housing 2, the aperture bridging the dividing wall 6 and a tubular sleeve 47 of rectangular cross section which is upstanding from the housing such that the bottom of the housing surrounds the periphery of the aperture 46. The top of the sleeve is capped by a plate 48 having a central opening 49. A fluid delivery pipe 50 projects upwardly from the plate 48, this pipe 50 enabling the connection of flexible hose or conduit for feeding the pumped material to a required location. The hose or conduit is not shown.

An inwardly directed flange or ledge 51 is located within the sleeve 47, the ledge 51 serving to support and sealingly engage with the peripheral region of a flap valve means 52 formed of rubber or other suitably resilient material. A central strip 53 of the flap valve 52 is connected to a support bar 54 bridging the aperture 46 immediately above the dividing wall 6. The support bar 54 is so shaped in relation to the dividing wall 6 that fluid cannot flow between the bar and the housing wall surface 17.

With the above mentioned mounting for the flap valve means 52 the latter is effectively constituted by two separate flap valves 55 and 56 and respectively associated with the housing sections 1A and 1 B. Also with this form of mounting the two flap valves 55 and 56 normally rest upon the flange 51 and are lifted away when the fluid pressure within the housing 1, during operation of the pump, increases above a value related to the characteristics of the material of the flap valves.

The above discussed pumping apparatus operates as follows:- The complete pumping apparatus is immersed in the fluid to be pumped. For example, the apparatus is immersed in a farmyard waste slurry pit, after having coupled the ram unit 40 to a suitable operating fluid supply and after having connected a delivery conduit to the pipe 50. For convenience, it will be presumed that the valve units involved are of the first form and that at the start of an operating cycle the valve unit 11 is about to be moved towards the dividing wall 6, that is the swept volume 57 of the valve unit 11 is at its maximum value. In addition, as will become apparant hereinafter the cup seal 1 4 will be positioned such that the sealing face thereof will be spaced from the plate 13.At the same time the valve unit 10 will be located at its closest setting relative to the wall 6 whereby the associated swept volume 58 will be at its minimum value, and the flange part 1 5 thereof will be closely adjacent to the associated plate 1 3.

On commencing movement of the valve unit 11 from the above mentioned initial setting it will be understood that the charge of fluid necessary to fill the swept volume 57 will have been able to enter the volume 57 by way of the cup seal 14 since the latter is not in its sealing position. On moving the valve unit 11 towards the wall 6 the presence of the fluid in the swept volume 57 will cause the cup seal 14 to move towards the plate 1 3 and after contact has been made between the flange part 1 5 and the plate 1 3 further movement of the plate 1 3 towards the wall 6 will commence to increase the pressure of the fluid within the swept volume 57 and thus press the sealing section of the seal 14 against the internal face 1 7 of the housing.

Once this condition has been attained further movement of the plate 1 3 towards the wall 6 will force the fluid from the swept volume 57 to open the flap valve 54 and to sweep the fluid into the delivery pipe 50. The presence of this liquid within the pipe 50 will hold the flap valve 55 closed.

During the movement of the valve unit 11 towards the wall 6 the valve unit 10 is simultaneously being moved away from the wall 6, thereby increasing the volume of the above mentioned swept volume 58. This outward movement of the valve unit 10 causes the cup seal 14 to move away from the contact with the associated plate 1 3 thereby releasing the sealing effect between this cup seal 14 and the housing wall 17. As a result fluid to be pumped is able to enter into the swept volume 58 to be progressively fill the latter as the valve unit 10 moves to its outmost position. At the end of this outward movement the valve arrangement 7 changes its direction of movement relative to the housing so that the fluid content of the swept volume 58 is discharged by way of the flap valve 55 and the other swept volume 56 is refilled as discussed.It will be noted that during this reverse movement the cup valve seal 14 of the unit 10 moves towards its associated plate 1 3 to effect the sealing action, and that the cup valve seal 14 of the unit 11 is displaced away from the associated plate 1 3 to break the sealing effect and to allow flow of fluid into the swept volume 57 to recharge the latter.

In other words through out the operation of the pump apparatus each cup valve seal 14 is alternately moved towards and away from its associated plate 1 3. Conveniently, the cup seals 14 are produced by splitting a vehicle tyre diametrically along the central diametrical plane into two halves such that each half provides a cup seal 14. With this arrangement the tread structure of the half tyre forms the seal part 1 6 that co-operates with the housing 1, and the tyre wall forms the flange section 1 5 which engages with the associated plate 13.

The pumping action produced by the second form of valve unit is generally similar to that of the first form except that the movement of the piston causes the flap valves formed by the pivotal mounting of the outer plate portions 24 to be pivoted towards the stop 32 to open the valve unit to allow admission of the fluid and to pivot back to the in-line position (shown in the Figures) in which fluid is retained within the housing to be forced out through the outlet conduit 50 by the pumping action. It wll be understood that when the outer portions 24 are in their in-line position with the central portion 23 the sealing part bears against the housing wall 1 7 and that during the compression period the seal is urged into contact with the surface 1 7.

Referring now to the embodiment of Figure 8 as will be noted the principle difference between the embodiment of Figure 8 and that of the previous Figures is that the single cylindrical housing of the previous Figures has been replaced by two axially spaced apart cylindrical housings 60. The housings 60 have associated therewith the valve units 10 and 11 which have constructions similar to those previously described so that further description will not be necessary. The valve units are operationally connected to the ram rods 61 and 62 of a double ended ram unit 63 whose housing or main body 64 effectively connects the housings 60 in the required end-to-end axial alignment.

The two housings are also interconnected by a pumped fluid or other material delivery pipe 65. Flap valves 66 and 67 are provided in the pipe to control the flow of pumped fluid or material from the housings 60. The delivery pipe 65 connects with a common outlet 68 having a function similar to the pipe 50 of the previously discussed embodiment. Hydraulic control connections for the ram unit 63 are schematically shown at 69.

In practice, the structure and the interconnection of the ram unit 63 with the housings 60 is such that the resulting assembly maintains the required axial alignment of the housings. If thought necessary additional strengthening frame members can be provided.

The operation of the pumping apparatus of Figure 8 is essentially the same as the mode of operation of the first embodiment so that a detailed discussion of the mode of operation of the Figure 8 embodiment is not thought necessary.

Claims

1. A fluid pump apparatus including a piston arrangement for reciprocation lengthwise of a pump housing to effect a pumping action, wherein the piston arrangement includes a first fluid sealing means of which at least a predetermined region thereof is allowed to undergo, with respect to the remainder of the piston arrangement, a limited amount of displacement to allow admission of fluid to be pumped.

2. A fluid pump apparatus as claimed in claim 1, wherein the pump is double acting, and wherein the piston arrangement incorporates first and second piston valve units arranged for axially movement of the housing and with each such unit including a sealing means which is allowed to undergo said limited displacement.

3. A fluid pump apparatus as claimed in claim 2, wherein the housing is common to both said piston valve units and is divided by an internal wall into two chambers, and wherein a valve unit is provided in each said chamber, and wherein means are provided for interconnecting the piston units so that that they are displaceable in unison relative to the housing.

4. A fluid pump apparatus as claimed in claim 2, wherein the housing comprises two separate housing sections which are so interconnected as to be axially aligned with each other, and wherein each housing section provides a chamber in which is located a piston unit, said piston units being interconnected so that they are displaceable in unison.

5. A fluid pump as claimed in claim 3 or 4, wherein the two piston valve units are interconnected by a connecting rod which is arranged to be displaceable axially of the housing by a ram arrangement.

6. A fluid pump apparatus as claimed in claim 1,2,3,4 or 5, wherein the or each piston valve unit incorporates a plate member adapted for connection to means for reciprocating the plate member with respect to the housing; an annular sealing element having a generally L-shaped cross section providing a first part for co-operation with at least the marginal or peripheral regions of the associated plate member and a second part for effecting sealing co-operation with the wall of the pump housing; and means for retaining the sealing element in a predetermined position relative to the plate member whilst allowing movement of the sealing element relative to the remainder of the valve unit during pumping operation.

7. A pump apparatus as claimed in claim 6, wherein the retaining means includes a plurality of retaining elements spaced around the plate member and arranged to provide a portion radially directed of the plate member and off-set therefrom for engagement with the sealing element first part on the face thereof remote from the plate member whilst allowing relative movement between the sealing element and the plate member.

8. A pump apparatus as claimed in claim 7, wherein the plate member is provided on the face thereof remote from the sealing element with second radially directed elements which are such as to prevent the sealing element from undesired bodily movement towards the remote side of the plate member.

9. A pump apparatus as claimed in claim 1,2,3,4 or 5, wherein each piston valve unit incorporates a plate member including an elongate central portion and two outer portions which are pivotally connected to the central portion, and wherein the sealing member has a first part secured to the peripheral regions of the three pivotally connected portions and a second part inclined to the first part for co-operation with the pump housing, whereby in operation the outer portions are enabled to pivot with respect to the central portion either to allow admission of fluid to be pumped into the associated housing or to retain the admitted fluid within the housing to enable the pumping therof to fluid discharge means; therebeing stop means for limiting the extent of pivoting in either direction.

10. A pump apparatus as claimed in claim 4,5 or 6, and including flap type valves for controlling the discharge of fluid from the apparatus, the arrangement being such that the pumping pressures automatically control the operation of the flap type valves.

11. A pump apparatus as claimed in any one of the preceding claims, wherein the housing is supported in such manner that the lowermost part thereof is above the ground level on immersion of the pump into a fluid to be pumped.

12. A pump apparatus as claimed in any one of the preceding claims, wherein the sealing means is produced by splitting a vehicle wheel tyre along the central plane thereof into two sections, and wherein each such section forms a sealing structure in which the tread structure of the tyre provides that part of the seal which is to co-operate with the housing.

13. A pump appartus constructed and arranged to operate substantially as herein before described with reference to Figures 1,2,3 and 4, Figures 2,5,6 and 7 or Figure 8 of the accompanying drawings.