GB2167501A - Pump having simplified access to the pump chamber for maintenance and cleaning - Google Patents

Abstract

The pump comprises a chassis 12, and a housing 14 attached to the chassis by four bolts 16 and an arm 44 pivotally connected to the chassis at 18. A pumping chamber 20 is formed between a diaphragm 22 and the housing 14 and a reciprocating drive from an engine 24 is applied to the diaphragm 22. When the bolts 16 are undone, the pump 10 may be rocked onto a leg 46 to move the housing 14 and the chassis 12 to the open position shown, in which the diaphragm 22 and the interior of the pumping chamber 20 are accessible. The chassis rocks about an axis 23 spaced from pivot 18. In a second embodiment two pumps, driven in antiphase are combined, with independent chassis. The diaphragm may be replaced by a piston/cylinder or a bucket arrangement. <IMAGE>

Description

SPECIFICATION Pump having simplified access to the pump chamber for maintenance and cleaning The present invention relates to pumps and is concerned especially, but not exclusively, with diaphragm pumps of the type commonly used in the construction industry, in which the pump, including a diesel engine providing power, are mounted on a common, wheeled chassis, so that the pump may be easily moved from place to place.

This type of pump is often used to pump water that contains a high proportion of solid material, such as silt, pond weed and stones. Some of the solids may collect in the pump chamber and interfere with the movement of the pumping member.

This reduces the efficiency of the pump and can cause damage to the drive mechanism of the pump.

In orderto prevent the pump chamber becoming blocked, regular cleaning is desirable. Known designs of diaphragm pump make regular cleaning difficult. The pump chamber housing is mounted on a chassis adjacent the diesel engine, with the diaphragm lying horizontally at the top of the pump chamber. Drive is applied to the diaphragm from above through a drive mechanism which may include an eccentric cam or a crank on a shaft driven by the diesel engine. The pump chamber is therefore sandwiched between the chassis and the drive mechanism. In order to obtain access to the pump chamber for cleaning or for replacing the diaphragm, at least the drive mechanism must be dismantled. This is a difficult operation which must be carried out by a trained mechanic in a workshop.

The pump must be taken away from the site and so there is a strong temptation not to carry out maintenance on the pump while it is working, with the result that the pump chamber continues to silt up until the pump is eventually damaged.

There is a need for a pump whose pump chamber and pumping member are more easily accessible.

The present invention provides a pump comprising a chassis carrying a pumping member and means operable to drive the pumping member, and a housing pivotally attached to the chassis so that the chassis and housing can be pivoted with respect to each other about a substantially horizontal pivot axis to move between a closed position in which a pumping chamber is formed between the housing and the pumping member, and an open position in which the pumping member and the interior of the pumping chamber are accessible, and means for releasably securing the chassis and housing in the closed position, the chassis being mounted to rock about a rocking axis substantially parallel to the pivot axis, so that, when the releasable securing means are released, the chassis can be rocked about its rocking axis to open and close the pumping chamber.

Large pumps, such as piston pumps for concrete, are known having housing which may be opened by pivoting the housing about a vertical axis. The use of substantially horizontal axes in the present invention allows the weight of the components of the pump to be utilised to advantage, as will be described.

According to a second aspect of the invention there is provided a pump comprising a chassis carrying a pumping member and means operable to drive the pumping member, and a housing pivotally attached to the chassis so that the chassis and housing can be pivoted with respect to each other about a pivot axis to move between a closed position in which a pumping chamber is formed between the housing and the pumping member, and an open position in which the pumping member and the interior of the pumping chamber are accessible, and means for releasably securing the chassis and housing in the closed position, the chassis being mounted to rock about a rocking axis spaced from the pivot axis, so that when the releasable securing means are released, the chassis can be rocked about its rocking axis to open and close the pumping chamber.

Further preferred features of a pump according to the invention are given below in the subsidiary claims, to which reference should now be made.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is an elevation, partly in section, of a pump according to the invention, shown with the housing and the chassis in their closed position; Figure 2 is a view like Figure 1, with the housing and the chassis in their open position; and Figure 3 is a plan view of an alternative embodiment, having two pumping chambers.

Referring to Figure 1, the pump 10 comprises a chassis 12, and a housing 14 mounted on the chassis 12 by releasable means 16, and a pivotal connection 18. When the releasable means are unfastened, the pivotal connection 18 allows the chassis 12 and housing 14 to pivot with respect to each other between a closed position (shown in Figure 1) in which a pumping chamber 20 is formed between the housing 14 and a pumping member, shown as a diaphragm 22, and an open position (shown in Figure 2) in which the diaphragm 22 and the interior of the pumping chamber are accessible. The pivot axis of the connection 18 is substantially horizontal and the chassis 12 is mounted on wheels 21 so that, when the releasable means 16 are released, the chassis can be rocked about the axis 23 of the wheels 21, to open and close the pumping chamber 20.

Drive means 24 including a diesel engine 26 are mounted on the chassis 12 and are operable to drive the pumping member 22. A reciprocating movement is applied to the diaphragm 22 through a wormgear (not shown), stub cranks 28 on either side of the wormgear and a U-shaped connecting rod 30 connected at its upper ends to the cranks 28 and to the diaphragm 22 at its lower end.

The connecting rod 30 extends through an aperture 31 in the chassis 12. In the closed position shown in Figure 1, the periphery of the diaphragm 22 is pinched, to form a fluid-tight seal, between the rim of the housing 14 and the rim of the aperture 31.

When the diaphragm 22 is moved upwardly, it draws liquid into the pumping chamber 20 through an inlet port 32 and a one-way inlet valve 34. When the diaphragm descends, it drives liquid from the chamber 20 through a one-way outlet valve 36 and an outlet port 38. Air columns 39, only one of which is shown, communicate with respective ports 32, 38 to smooth shocks caused by the changed in the direction of movement of the diaphragm 22.

The pump 10 is supported on a pair of wheels 21 (only one of which is shown in Figures 1 and 2) mounted on the chassis 12 and having a common rotation axis 23. When the pump 10 is resting on the ground with the housing and the chassis in their closed position (Figure 1), its weight is distributed between the wheels 21 and a foot 42 formed in the outer surface of the housing 14. That is, the wheels are positioned on the chassis 12 so that the centre of gravity of the chassis and the apparatus carried by the chassis is to the left (as seen in Figures 1 and 2) of the axis 23 of the wheels 21. In this position the chassis rests on the housing and the weight of the chassis and the apparatus by the chassis tends to retain the chassis and housing in the closed position shown.

The housing 14 is mounted on the chassis 12 by four bolts 16, only two of which are shown in Figures 1 and 2, and two arms 44, only one of which is shown. The arms 44 are attached to the housing 14 at one end and are pivotally mounted to the chassis 12 by the pivotal connection 18 at their other end, so as to have a common pivot axis. This axis is on the opposite side of the axis 23 to the housing 14. The pivotal mounting 18 comprises a cross shaft mounted on to the arms 44 and located by cross pins, and journalled in bores in the chassis 12.

A ground-engaging leg 46 is mounted on the chassis 12 on the same side of the axis 23 as the axis of the mounting 18. When the pump is resting on the wheels 21 and the foot 42, the leg 46 is off the ground. However, when the bolts 16 are undone, the pump may be rocked on the wheels, about the axis 23, to move the pump into the open position shown in Figure 2. In this position the weight of the pump is distributed between the wheels 21 and the leg 46.

The wheel position and the length of the leg 46 may be chosen so that, in the position shown in Figure 2, the centre of gravity of the chassis and the apparatus carried by the chassis is between the axis 23 and the axis of the connection 18. The weight of the chassis and the apparatus it carries thus tends to retain the pump in the open position shown.

In the open position, the housing 14 remains resting on the ground, and the diaphragm 22 and the interior of the pumping chamber 20 are accessible. A workman may use a tool or put his arm between the housing 14 and the chassis 12withoutdanger because the pump is stable in this position. Silt may be cleaned from the pumping chamber 20 and the diaphragm 22 may be replaced by releasing the nut 48 which holds it to the connecting rod 30.

When cleaning and maintenance are complete, the pump is simply rocked back to the closed position of Figure 1 by depressing the handle 47. The housing 14 and the chassis 12 correctly align themselves automatically, because of the connection 18 between them.

The separation of the housing 14 and the connection 18 provides adequate access to the pumping chamber in the open position without a large angle being required between the housing and the chassis.

This in turn avoids the bolts 16, which rotate while entering and leaving their sockets, becoming jammed in the sockets as the pumping chamber is opened or closed. Once the pump has been closed and the bolts 16 have been tightened, the pump is again ready to be used. The diesel engine 26 and the drive transmission between the engine 26 and the pumping member 22 have centres of gravity on opposite sides of the axis about which the chassis rocks, so that they each act as counter-weights for the other during rocking. This makes opening and closing the pump less strenuous tasks.

The wheels 21 are mounted on a sub-chassis, the position of which may be adjusted in the forwards and backwards direction, so that the axis 21 may be moved with respect to the centre of gravity of the chassis and apparatus it carries, in order to obtain the relative positions described above. In this way, alternative apparatus, in particular alternative diesel engines 26 of different sizes and weights, can be accommodated without losing the mechanical advantages described. It may be desired at some time to replace the diesel engine by an alternative power source, for instance an electric motor. The adjustable mounting enables the sub-chassis to be moved to compensate for any change in the centre of gravity resulting from the change of engine.

The sub-chassis is a bracket mounted on the chassis by means of bolts extending through apertures in the bracket and elongate slots in the chasses. The slots allow the sub-chassis to be moved with respect to the chassis and nuts can be tightened on the bolts to hold the chassis and sub-chassis in a chosen relative position. The subchassis also carries a lifting bar 58 to which lifting gear may be attached. The bar 58 is offset from the axis 23 so that it may be aligned with the centre of gravity of the pump, while the axis is offset.

The inlet and outlet valves 34,36 are flap valves formed by identical flaps 34, 36 mounted on a valve plate 52 over the apertures 50 in the plate 52, and on opposite sides of the plate 52. Small rigid plates or bars 56 may be used to limit the range of movement of the flaps 34,36. The plate 52 is bolted to the housing 14. The apertures 50 communicate with the inlet and outlet ports 32,38 through a partitioned housing 54, on which the air columns are mounted.

Access to the pumping chamber 20 and to the diaphragm 22 may be further facilitated, when the housing and chassis are in the open position of Figure 2, by removing the housing 54 (and the air columns 39) and the plate 52.

Manufacturing and maintenance costs of the valve assembly are reduced as compared with those of the valve assemblies of known pumps which are separate valves in individual mountings. Bolts (not shown) mounting the plate 52 to the housing 14 allow the whole valve assembly to be replaced quickly and easily, as a single unit.

An alternative embodiment of the pump 10 is shown in Figure 3, in which integers equivalent to integers shown in Figures 1 and 2 are indicated by the same numerals.

The pump 10 of Figure 3 has two pumping chambers side by side, formed between respective diaphragms 22 and respective housings 14. The edges of the diaphragms are pinched between rims on the housings and the chassis. The housings are independently mounted on the chassis 12 by pivotal connections 18 and bolts 16, so that they may be opened either separately or together, in the manner described above with reference to Figures 1 and 2.

Each stub crank 28 drives a respective diaphragm 22.

Inlet and outlet valves to each chamber are provided by respective assemblies comprising a valve plate 52 identical to the plates shown in Figures 1 and 2, and carrying flap valve members (not shown). The chambers communicate with inlet and outlet ports of the pumps through a partitioned manifold 54.

Preferably, the diaphragms of the double chamber pump shown in Figure 3 are driven in anti-phase, so that liquid is drawn into and expelled from the pump more smoothly than in the single chamber pump described above.

Although the pumps described above use diaphragms with fixed edges as their pumping members, alternative pumping members could be used, for instance pistons. Diaphragms having free-edges which act as non-return valves between a pumping chamber below the diaphragm and a delivery chamber above the diaphragm could also be used. In pumps of this type, liquid is driven from the pumping chamber to the delivery chamber when the diaphragm descends, and is both drawn into the pumping chamber through the inlet port and expelled from the delivery chamber through the outlet port when the diaphragm rises. It is the lower pumping chamber which is most likely to silt up, and accordingly the present invention is also applicable to this type of diaphragm pump.

Claims (25)

1. A pump comprising a chassis carrying a pumping member and means operable to drive the pumping member, and a housing pivotally attached to the chassis so that the chassis and housing can be pivoted with respect to each other about a substantially horizontal pivot axis to move between a closed position in which a pumping chamber is formed between the housing and the pumping member, and an open position in which the pumping member and the interior of the pumping chamber are accessible, and means for releasably securing the chassis and housing in the closed position, the chassis being mounted to rock about a rocking axis substantially parallel to the pivot axis, so that, when the releasable securing means are released, the chassis can be rocked about its rocking axis to open and close the pumping chamber.

2. A pump according to claim 1 in which the pivot axis is spaced from the rocking axis.

3. A pump according to claim 2 in which the rocking axis lies between the pumping chamber and the pivot axis.

4. A pump according to claim 2 or 3 in which the housing is pivoted to the chassis by means of an intermediate member which spaces the housing horizontally from the pivot axis.

5. A pump according to any preceding claim, wherein the rocking axis is so located that, in use, the centre of gravity of the chassis and the means carried out by the chassis moves from one side of the rocking axis to the other when the pumping chamber is opened or closed, so that the weight of the chassis and the means carried by the chassis tends to retain the chassis and housing in the open and closed positions when they are in the respective positions.

6. A pump according to any preceding claim in which means are provided for permitting movement of the rocking axis relative to the chassis so that the horizontal position of the rocking axis relative to the centre of gravity of the chassis and the means mounted on the chassis can be adjusted.

7. A pump according to claim 6 in which the rocking axis is provided on a sub-chassis which is adjustably mounted on the chassis.

8. A pump according to claim 7, in which the sub-chassis is mounted on the chassis by means of a slide mechanism comprising meansforfixing the sub-chassis and chassis in relative positions to which they have been slid.

9. A pump according to claim 8, wherein the slide mechanism comprises a member located in an aperture in the chassis or sub-chassis and in an elongate slot in the sub-chassis respectively.

10. A pump according to claim 9, wherein the said member of the slide mechanism is the bolt of a nut and bolt assembly, the shank of the bolt being located in the aperture and the slot and the nut and bolt assembly being capable of being tightened to prevent movement of the shank along the slot.

11. A pump according to any preceding claim, in which the rocking axis is the common axis of a pair of ground engaging wheels.

12. A pump according to any preceding claim, wherein the drive means comprises a power unit and a drive transmission connected between the power unit and the pumping member, the centres of gravity of the power unit and the drive transmission being located on opposite sides of the rocking axis so that the power unit and the transmission act as counter-weights for one another.

13. A pump according to claim 12, wherein the power unit is interchangeable with a power unit of different weight.

14. A pump according to any preceding claim, wherein, in the closed position, part of the weight of the chassis and the means carried by the chassis is supported by the housing which, in turn, is sup ported on the ground.

15. A pump according to any preceding claim, wherein the pumping member is a flexible di aphragm.

16. A pump according to claim 15, wherein, in the closed position, the edge of the diaphragm is pinched between a rim on the chassis and a rim on the housing, to form a fluid-tight seal.

17. A pump according to any preceding claim, comprising inlet and outlet ports which communi cate with the pumping chamber through apertures in a valve-supporting member, and valves mounted on the valve-supporting member for controlling flow through the apertures.

18. A pump according to claim 17, wherein the valve-supporting member forms part of the wall or walls of the pumping chamber, and is removable, at least in the open position, to facilitate access to the pumping chamber.

19. A pump according to any preceding claim, in which the chassis carries a further pumping member driven by the drive means and a further housing attached to the chassis for pivoting about the pivot axis, the chassis and the further housing being pivotable with respect to each other between a closed position in which a further pumping chamber is formed between the further housing and the further pumping member, and an open position in which the further pumping member and the interior of the further pumping chamber are accessible, and the chassis and the further housing being releasably securable in the closed position, whereby, when one or both releasable means are released the chassis may be rocked about its rocking axis to open and close the pumping chambers separately or together.

20. A pump according to claim 19, having an inlet and an outlet port each communicating with the pumping chamber and the further pumping chamber.

21. A pump comprising a chassis carrying a pumping member and means operable to drive the pumping member, and a housing pivotally attached to the chassis so that the chassis and housing can be pivoted with respect to each other about a pivot axis to move between a closed position in which a pumping chamber is formed between the housing and the pumping member, and an open position in which the pumping member and the interior of the pumping chamber are accessible, and means for releasably securing the chassis and housing in the closed position, the chassis being mounted to rock about a rocking axis spaced from the pivot axis, so that when the releasable securing means are released, the chassis can be rocked about its rocking axis to open and close the pumping chamber.

22. A pump according to claim 21,wherein the rocking axis and the pivot axis are parallel.

23. A pump according to claim 22, wherein the pivot axis and the pumping chamber are positioned on respective sides of the rocking axis.

24. A pump substantially as described above with reference to Figures 1 and 2 of the accompanying drawings.

25. A pump substantially as described above with reference to Figure 3 of the accompanying drawings.