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Title:
IMPROVEMENTS IN AND RELATING TO PUMPS
Document Type and Number:
WIPO Patent Application WO/2004/005723
Kind Code:
A2
Abstract:
The invention provides a pump apparatus comprising a housing having pump means located therein; attachment means for releasably attaching the apparatus operably to drive means for driving the pump means; wherein said attachment means are adapted to attach to a powered garden implement. The invention further provides a pump impeller assembly, having blades located between two discs, the blades optionally being of an aerofoil section, suitable for use in such a pump apparatus.

Inventors:
MANNING JOHN PATRICK (GB)
Application Number:
PCT/GB2003/002838
Publication Date:
January 15, 2004
Filing Date:
July 02, 2003
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
MANNING JOHN PATRICK (GB)
MITCHELL HARRY DAVID (GB)
International Classes:
F04B17/05; F04D13/02; (IPC1-7): F04D13/02; F04B17/05
Foreign References:
US4286675A1981-09-01
US5148992A1992-09-22
US3616867A1971-11-02
US6494674B12002-12-17
US3402668A1968-09-24
EP1186782A12002-03-13
Attorney, Agent or Firm:
I.P.21 LIMITED (Norwich Research Park, Colney, Norwich NR4 7UT, GB)
Download PDF:
Claims:
CLAIMS
1. A pump apparatus comprising: a housing having pump means located therein; attachment means for releasably attaching the apparatus operably to drive means for driving the pump means; wherein said attachment means are adapted to attach to a powered garden implement.
2. A pump apparatus according to claim 1 wherein the garden implement is a strimmer.
3. A pump apparatus according to any preceding claim wherein the attachment means comprises a collar arranged to engage a casing.
4. A pump apparatus according to any preceding claim wherein the housing comprises a generally open face, said generally open face allowing, in use, the pump means to be at least partially immersed in a liquid to be pumped.
5. A pump apparatus according to the previous claim wherein the housing additionally comprises a guard member, releasably attachable to the housing.
6. A pump impeller assembly comprising: a first disc, adapted to operably connect to a rotating drive; a second disc, perforated to allow passage of a fluid, and located generally parallel to the first disc and separated therefrom; and a plurality of blades, connected to at least the first disc, and located between the first and second discs, extending inwardly from adjacent the periphery of the discs towards the centre, defining a plurality of tapering cavities therebetween.
7. A pump impeller assembly according to the previous claim wherein at least one of the blades is aligned along a nonradial chord of the first disc.
8. A pump impeller assembly according to any of claims 6 to 7 wherein the perforation of the second disc comprises a single hole in the centre of the disc.
9. A pump impeller assembly according to any of claims 6 to 8 wherein the leading face of at least one of the blades is convex.
10. A pump impeller assembly according to any of claims 6 to 9 wherein at least one of the blades comprises an aerofoil section.
11. A pump impeller assembly according to any of claims 6 to 10 wherein the cavity facing face of at least one of the discs is convex.
12. A pump impeller assembly according to any of claims 6 to 11 wherein at least one of the blades comprises sealing means to enhance a seal between the outer extents of the blade (s) and a surrounding housing.
13. A pump impeller assembly according to any of claims 6 to 12 wherein the sealing means comprises moveable vanes located within cavities defined in the vanes.
14. A pump apparatus substantially as described herein with reference to and as illustrated by any appropriate combination of the accompanying drawings.
15. A pump impeller assembly substantially as described herein with reference to and as illustrated by any appropriate combination of the accompanying drawings.
Description:
IMPROVEMENTS IN AND RELATING TO PUMPS Field of the Invention The present invention relates to pumps and a pump attachment for use with devices and an assembly comprising a device and a pump attachment.

Background to the Invention Standing water in gardens etc. can cause problems to the surrounding area and, especially, if the water congregates adjacent to a building. Such water also increases the risk of flood occurring as the height of the standing water increases. At present, standing water can be manually brushed towards drainage area in order to try and dispose the water. However, this method is not efficient and is not effective when used on particular surfaces. In addition, this method relies on the presence of a drainage area nearby.

Alternatively, a pump, such as a bilge pump may be secured in an area where water is expected to congregate, for example in the bottom of a boat. Accordingly, such pumps cannot be used in a number of areas where flooding may occur, for example several pools may form on a paved area and for which a bilge pump would not be suitable.

Furthermore, existing systems exhibit a range of other shortcomings for dealing with shallow standing water. Most pumps are not self-priming and require a significant depth of water to be able to operate. Many are able, therefore, to pump water and other fluids which are present to a considerable depth, but become inoperable when the fluid is shallow.

It is an aim of the present invention to overcome at least one problem associated with the prior art whether referred to herein or otherwise.

Summary of the Invention The present invention provides a solution to overcoming the problems of pumping water and other fluids, by providing pump apparatus that may be detachably mounted to an external drive source such as a powered garden implement (eg. a strimmer, hedge trimmer, lawn mower or lawn edger). There is also provided as an aspect of the invention a pump impeller assembly providing pumping means suitable for use in such an apparatus.

In its broadest aspect, the invention provides a pump apparatus comprising: a housing having pump means located therein ; attachment means for releasably attaching the apparatus operably to drive means for driving the pump means; wherein said attachment means are adapted to attach to a powered garden implement. Preferably, the garden implement is a strimmer.

Preferably also, the attachment means comprises a collar arranged to engage a casing.

In any embodiment of the invention, the housing comprises a generally open face, said generally open face allowing, in use, the pump means to be at least partially immersed in a liquid to be pumped.

Preferably also, the housing additionally comprises a guard member, releasably attachable to the housing.

The invention also provides, as a second aspect, a pump impeller assembly comprising: a first disc, adapted to operably connect to a rotating drive; a second disc, perforated to allow passage of a fluid, and located generally parallel to the first disc and separated therefrom ; and a plurality of blades, connected to at least the first disc, and located between the first and second discs, extending inwardly from adjacent the periphery of the discs towards the centre, defining a plurality of tapering cavities therebetween.

Preferably, at least one of the blades of the pump impeller assembly is aligned along a non-radial chord of the first disc.

Preferably also, the perforation of the second disc of the pump impeller assembly comprises a single hole in the centre of the disc.

Preferably also, the leading face of at least one of the blades of the pump impeller assembly is convex.

Preferably also, at least one of the blades of the pump impeller assembly comprises an aerofoil section.

Preferably also, the cavity-facing face of at least one of the discs of the pump impeller assembly is convex.

Preferably also, at least one of the blades of the pump impeller assembly comprises sealing means to enhance a seal between the outer extents of the blade (s) and a surrounding housing.

Preferably also, the sealing means of the pump impeller assembly comprises moveable vanes located within cavities defined in the vanes.

The scope of the invention encompasses a pump apparatus substantially as described herein with reference to and as illustrated by any appropriate combination of the accompanying drawings.

The scope of the second aspect of the invention encompasses a pump impeller assembly substantially as described herein with reference to and as illustrated by any appropriate combination of the accompanying drawings.

Furthermore, according to an aspect of the present invention there is provided pump apparatus for pumping a liquid comprising a housing having pump means located therein, the apparatus comprising attachment means for attaching the apparatus to a drive unit for driving the pump means.

Preferably the attachment means releasably attaches the apparatus to the drive unit.

The drive unit may be provided by a garden implement. Preferably the drive unit is provided by a garden strimmer. Accordingly, the attachment means is arranged to attach the apparatus to the base of the garden strimmer once the strimming device has been removed from the drive unit.

The attachment means may comprise a collar which is arranged to engage a casing and preferably a substantially cylindrical casing. The casing may house a drive shaft. The attachment means may comprise an annular member which is arranged to urge the collar inwardly in order to reduce the aperture in the collar.

Preferably the collar comprises a first section and second section. The collar may comprise a first arcuate section and a second arcuate section. The first and second section may comprise substantially'L'shaped members. The first and second arcuate sections may be urged together, in use, in order to attach the pump apparatus to the drive unit.

Preferably the housing has an outlet defined therein in order for liquid to flow from inside the housing to outside the housing. The outlet may enable a conduit to be secured thereto in order for the liquid to flow along a predetermined pathway to an area spaced from the pump apparatus.

The housing may have a generally open lower face in order for the pump means to be at least partially immersed in the liquid.

The pump means may comprise an impeller. Preferably the impeller comprises a disc shaped member having a plurality of blades mounted thereon. Preferably, adjacent blades define an outwardly tapered area there between and may define a truncated triangular area there between. Preferably the or each blade is aligned on a chord of the disc shaped member. Each blade may have a curved or convex leading surface. The impeller may comprise an impeller casing. The impeller casing may define a cavity in which the blades are arranged to rotate. The cavity may comprise an annular tapered region which tapers outwardly away from the centre.

Each blade may comprise sealing means to enhance a seal between the outer extents of the blade and the surrounding housing. The sealing means may comprise vanes which are located within cavities defined in the blades. The sealing means may comprise a resilient material. The vanes may be movably and preferably radially movably in the cavities in the blades. Preferably as the impeller rotates the resulting force causes the vanes to move radially outwardly to enhance a seal between the blade and the surrounding housing.

Preferably as the impeller rotates, a region of low pressure is created in a central area of the impeller. Preferably, the area of low pressure creates a suction force to suck the liquid in to the impeller.

The apparatus may comprise a guard member. The guard member may comprise a disc shaped member. The disc shaped member may have a plurality of slots defined therein.

Preferably the guard member is releasably attached to the housing.

According to a further aspect of the present invention there is provided an assembly comprising a pump attachment and a drive unit, the pump attachment being in accordance with the first aspect of the present invention.

The drive unit may comprise a garden implement. Preferably the drive unit comprises a garden strimmer.

The drive unit may comprise a cylindrical casing. Preferably the pump attachment comprises attachment means which is arranged, in use, to secure the pump attachment to a part of the cylindrical housing of the drive unit.

According to another aspect of the present invention there is provided a method of pumping a liquid comprising attaching apparatus according to the first aspect of the present invention to a drive unit.

The method may comprise locating a part of the pump apparatus in a liquid. Preferably the method comprises at least partially immersing the housing of the pump apparatus in a liquid.

The method may comprise securing a conduit to the housing of the pump apparatus.

The method may comprise attaching the pump apparatus to a housing of the drive unit.

The method may comprise urging a first and second member together in order to engage a part of the drive unit.

According to another aspect of the present invention there is provided a kit comprising pump apparatus according to a first aspect of the present invention and a plurality of attachment means.

Brief Description of the Drawings The present invention will now be descried, by way of example only, with reference to the drawings that follow, in which: Figure 1 is an exploded cross-section of an embodiment of the present invention.

Figure 2 is an exploded cross-section of an embodiment of the present invention.

Figure 3a is a cross-section of an embodiment of the present invention.

Figure 3b is a cross-section through X-X of Figure 3a.

Figure 4 is a cross-section of an impeller of an embodiment of the present invention.

Figure 5 is a cross-section of an impeller of an embodiment of the present invention.

Figure 6 is a top view of an impeller of an embodiment of the present invention.

Figure 7 is an underneath view of an impeller of an embodiment of the present invention.

Figure 8 is a cross-section of a housing of an embodiment of the present invention.

Figure 9 is a cross-section of a housing of an embodiment of the present invention.

Figure 10 is a bottom view of a housing of an embodiment of the present invention housing a guard member secured thereto.

Figure 11 is a bottom view of a guard member of an embodiment of the present invention.

Figure 12 is a side view of a guard member of an embodiment of the present invention.

Figure 13 is a top view of part of an attachment collar of an embodiment of the present invention.

Figure 14 is a cross-section of part of an attachment collar of an embodiment of the present invention.

Figure 15 is a cross-section of another embodiment of an impeller.

Figure 16 is cross-section of another embodiment of an impeller located within a housing.

Figure 17 is a side cross-section of part of another embodiment of an impeller.

Figure 18 is a cross-section of an embodiment of an impeller having aerofoil-shaped blades.

Figure 19 is a cross-section of an embodiment of an impeller assembly showing convex discs.

Figure 20 is a cross-section of an embodiment of a pump impeller assembly having convex discs and a guard member.

Description of the Preferred Embodiments As shown in Figure 1, Figure 2 and Figures 3a and 3b the pumping apparatus 10 comprises a pump attachment 12 which is arranged to be secured to a conventional device and especially a garden implement, for example a strimmer 14. In particular, the pump attachment 12 is designed to replace the existing implement head. Alternatively, the pump attachment 12 may be attached to a different device comprising a rotating drive shaft. The strimmer 14 comprises a motor within a housing 16 which is arranged to rotate a drive shaft 18. The drive shaft is housed in a casing 28. The pumping apparatus is designed to be enclosed without having any exposed parts of exposed electrics and is designed to be manually held and, therefore portable, rather than located within a specific piece of equipment.

The drive shaft may be driven by an internal combustion engine or an electric motor or preferably by an air or pneumatic motor. Preferably, the motor does not require a plug socket which may restrict or limit the portability of the pumping apparatus. Furthermore, non-electric motors are preferred in order to reduce the risk of an electric shock.

The pump attachment 12 comprises attachment means in order to attach the pump attachment to the trimmer 14 once the conventional strimmer attachment is removed. The pump attachment 12 includes a housing 20. Within the housing, fluid flow means in the form of an impeller 22 is mounted. A guard member 23 is mounted on to the base of the housing.

In use, the pump attachment 12 is partially immersed in the liquid to be dispersed. Once powered, the drive shaft 18 is cased to rotate which, thereby, causes the impeller 22 to rotate. At least a part of a blade 50 of the impeller is immersed in the liquid and rotates.

The impeller 22 causes the liquid to flow generally radially within the housing 20.

The housing 20 has an outlet 24 provided on its periphery. Accordingly, as the fluid circulates it is caused to low out of the housing through the outlet 24. A conduit 25 is secured to the external section of the outlet 24 and extends from the housing 20 to an area spaced from the fluid to be dispersed. Accordingly, the fluid is caused to flow out of the housing 20 through the outlet 24 and through the conduit 25 to a selected area for the fluid to be dispersed to. Such a selected area may include drainage means and may be a drain.

The housing 20 preferably comprises a corrosion resistant material and may be a casting or a moulding.

The pump attachment 12 is secured to the strimmer 14 by firstly securing an annular collar 26 around the cylindrical casing 28 of the strimmer 14, as shown in Figure 2. The collar 26 comprises two arcuate (preferably semicircular) sections which define an aperture there between to engage with the periphery of the casing 28. Once the collar 26 is in position, the housing 20 is positioned over the end of the strimmer 14 such that a sleeve portion 30 of the housing 20 locates over the collar 26. A securement collar 31 is then tightened over the sleeve portion 30 of the housing 20 which urges the two arcuate sections of the collar 26 together and reduces the aperture defined therebetween. This thereby causes the pump attachment 12 to be attached to the casing 28. In an alternative embodiment the securement means or collar 31 may be integral with the housing 20.

The annular collar 26 preferably comprises a corrosion resistant material and may comprise a deformable or resilient material. The deformable or resilient annular collar 26 is arranged to take the form of the contact face of the implement and thereby improves the engagement between the implement and the annular collar 26.

The impeller 22 comprises a disc 48 having blades 50 mounted thereon, as shown in Figures 4 to 7. The disc 48 has a central aperture 52 in order for the drive shaft to project

therethrough. The drive shaft is secured to the impeller such that rotation of the drive shaft enables rotation of the impeller. The drive shaft may be secured to the impeller by way of a threaded hole in the impeller and a matching thread on the drive shaft.

Alternatively, the drive shaft may comprise a splined or a tapered shaft which is arranged to secure the drive shaft to the impeller.

The impeller may comprise six blades 50. Alternatively, a different number of blades 50 may be used. The blades 50 are mounted on a planar surface of the disc 48 and extend inwardly from the periphery of the disc 48. The blades 50 do not extend towards the central aperture but are angled in order to induce fluid flow when rotating. The blades also have a tapered inner edge 54 which tapers outwardly from the surface of the disc.

The impeller 22 is arranged to rotate in the direction of the arrow 53 as shown in Figure 4.

Accordingly, the blades direct the liquid outwardly and induce radial fluid flow against the inside of the housing 20.

The impeller 22 includes a casing 56 as shown in Figure 6 and Figure 7. The lower face 58 of the casing is annular and thereby enables fluid to flow into the casing 56.

The casing 56 of the impeller 22 has an opening 57 defined on its lower face in order for liquid to enter into the casing. Once powered the impeller causes the liquid to circulate in the casing and as the liquid flows through the outlet 24 in an area of lower pressure or a vacuum, is more liquid to flow through the opening 57 and into the casing 56 of the impeller 22.

As shown in Figure 4, adjacent blades 50 of the impeller define an outwardly tapered area therebetween. The adjacent blades 50 include a leading blade 82 and a trailing blade 80 as defined in the pair by the direction of rotation 53. The blades 80, 82 defined a relatively small entry channel for the liquid to enter into the tapered area, and a relatively large exit channel for the liquid to flow out from between adjacent blades. This effectively creates a region of low pressure in the centre of the impeller such that a suction force is created in order for further liquid to be sucked into the impeller through the opening 57. This suction force causes the apparatus to be urged towards the surface from which the liquid is being removed.

The tapered area is of a truncated triangle shape or is essentially triangular in shape, if the trailing blade 80 were to be extended in order to coincide with the lead blade 82, as shown in Figure 4. In addition, the inner face of the trailing blade 80 may be aligned with the innermost edge 84 of the leading blade 82.

The triangular area is a scalene triangle wherein the angle 86 is defined at the innermost edge of the leading blade 82 may be of the order of 50° to 70° and preferably in the region of 60°. The angle 88 between the inner surface of the trailing blade 80 and the imaginary line 83 joining the outermost edges of the blades 80, 82 may be of the order of 40° to 60° and preferably in the region of 50°. Finally, the angle 90 between the imaginary line 83 joining the two outermost edges of the blades 80, 82 and the inner surface of the leading blade 82 may be of the order 70° to 90° and preferably is in the region of 80°.

This scalene triangle shape is more effective than a conventional equilateral triangle shape. The shape encourages liquid to enter the area and is then ejected outwardly of the area between the adjacent blades 80,82. The blades do not lie on a radius of the disc 48 of the impeller 22 but are arranged on a part of a chord of the disc 48. The triangular shape is not, therefore, a sector of the disc as with conventional impellers. The blades may have straight leading and trailing surfaces or the blades may comprise curved surfaces (not shown).

The housing 20 has a lower castellated edge 60, as shown in Figures 8 to 10. The outlet 24 extends tangentially out from the housing 20. The housing 20 has a shaped inner surface area 62 in order to direct the fluid to flow out of the housing 20 and through the conduit 26. The housing 20 may have a guard member secured thereto which has a lower face having slots 72 defined therein. The slots 72 may prevent relatively large objects from entering the housing 20.

The pump attachment 12 may comprise a guard member 23 to prevent the ingress of debris into the housing, as shown in Figure 11 and Figure 12. The guard member 23 may comprise a generally disc member 70 having a plurality of openings or slots 72 defined therein.

The collar 26 comprises two semi circular sections, as shown in Figure 13. Each section may comprise a resilient material in order to enhance the grip between the collar and the casing of the strimmer. The resilient material may comprise rubber. In addition, the inner surface 27 of the sections may be ribbed in order to aid the grip between the collar and the casing. The sections have a flange 29 which is arranged to abut the upper edge of the housing of the pump attachment, in use.

The inner surfaces 27 of the collar 26 comprise a resilient material in order to enable the pump attachment 12 to be attached to casings 28 not being perfectly circular. The resilient material may deform to enable the pump attachment to be attached to different shaped casings, for example hexagonal. The shape of the casing 28 may be dependent upon the implement to which the pump attachment 12 is to be attached or the model of the implement, for example different models of garden strimmers may have different shaped casings. This enables the pump attachment 12 to be used with a variety of implements.

However, if the pump attachment is to be attached to casings 28 having significantly different cross-sections for which the resilient material cannot deform sufficiently to ensure a suitable seal, the apparatus 10 may comprise different collars 26 defining different shaped apertures. For example, the apparatus may have two substantially'L' shaped members to attach to a casing having a quadrilateral cross-section. The apparatus may, therefore, be a kit including a single pump attachment with a plurality of different collars to enable the attachment to be attached to a variety of models of implements as well as to different implements.

The collar 26 comprises two sections since this enables the collar to be easily located around the casing 28. The drive shaft 18 may have a relatively large nut or other attachment at its lower end which may be bigger than the casing 28 and, therefore, the nut may not be able to be pushed through an aperture in a collar comprising a single member.

Accordingly, since the collar is in two sections this problem is overcome.

Initially, the housing may be secured to the garden implement followed by the impeller.

Finally, the guard member 23 is secured using a simple press fit so as to be quickly removed for cleaning and dismantling of the pump.

As shown in Figure 15, Figure 16 and Figure 17, an alternative impeller comprises blades 50 wherein the blades 50 each have a curved leading face 100. This face 100 in conjunction with the trailing face 102 (which may be straight) of the adjacent blades forms both an expanding wedge from the centre hub and a constricting area at the outer leading face of the blade. Furthermore, the cross-section of the cavity 108 of the impeller casing 107 is wedge shaped as shown in Figure 17. The shaped blades 50 and/or shaped cavity 108 produce a higher suction force at the input of the pumping apparatus.

In addition, the blades 50 of the impeller 22 each comprise a cavity 104. Within each cavity 104 is a vane 106 which is radially movable relative to the blade 50. In use, once rotating, the vanes 106 are forced outwardly by the centrifugal force and co-operate with the inner surface of the housing 20. This creates and encourages a seal to form which thereby increase the suction force and the force ejecting the liquid.

The result of the shaped blades and/or shaped cavities and/or vanes enables the pumping apparatus to self prime which previous centrifugal pumps cannot achieve.

Figure 18 illustrates a cross-section of an embodiment of the invention. In this embodiment a number of blades 200 are provided having a leading surface of a generally convex or aerofoil section. (In this illustration the impeller assembly would rotate anti- clockwise). Choice of a suitable aerofoil section for blades depends upon the rotational speed of the intended drive means. Generally, a high rotational speed would be best matched to a relatively flat aerofoil section. Conversely, a slower rotational speed would be best served by a thicker aerofoil section. In implementing an embodiment of this invention comprising aerofoil-shaped blades, the skilled man is referred to the field of aeronautical engineering for suitable designs of aerofoil sections. For example,'Theory of Wing Sections: Including a Summary of Airfoil Data', Abbott, I. H. and von Doenhoff, A. E. , Dover Publications, 1980, ISBN 0486605868 and'The Elements of Aerofoil and<BR> Air Screw Theory' (Cambridge Science Classics) ', Glauert, H. , Cambridge University Press, 1983, ISBN 052127494X.

In this embodiment, the blades are further provided with cavities 201 to accommodate sealing means (not shown) to enhance the seal between the outer extents of the blades 200 and the surrounding housing (not illustrated). Also shown in this illustration is a first plate 202 or disc to which the blades are attached. In this embodiment the leading faces of the blades 200 are aligned generally along a chord of the disc 202, illustrated by the line 203. Further illustrated is the location of a single perforation 204 provided on a second disc of the invention.

Figure 19 illustrates a cross-section through a pump impeller assembly according to the present invention. In this embodiment, the first disc 202 is adapted to operably connect to a rotating drive by the provision of a central hole 208. The inner, i. e. cavity-facing, face of the first disc 202 is generally convex 205. Similarly, the second disc 209 has a convex inner (i. e. cavity facing) surface 206. This second disc 209 has a perforation comprising a single central hole, the edge of which is shown at 204. Also illustrated in this embodiment is the position of an impeller blade 207 extending from adjacent the periphery of the disc 202 towards the centre of the pump impeller assembly.

Figure 20 shows an embodiment of the invention with the pump impeller assembly, generally 210, located within a housing 211. The housing 211 is provided with a guard member 212, releasably attached to the housing 211, and comprising a plurality of perforations 213.

The invention is defined by the claims that follow in which"powered garden implement" is intended to cover those items of powered equipment designed for, or marketed specifically for, garden work. Therefore, by way of example only, items such as hedge trimmers, strimmers (rotatory trimmers), lawn mowers and lawn edgers fall into the category of powered garden implements. By contrast however, and by way of example only, items such as cement mixers and electric drills, whilst being able to be used in gardens, would not fall into the scope of"powered garden implements". Other items, such as powered"jet washers", marketed for use in gardens for cleaning patios and other surfaces would, however, fall into the scope of"powered garden implements".