WO2005059360A1

WO2005059360A1 - Piston pump

Info

Publication number: WO2005059360A1
Application number: PCT/AU2004/001759
Authority: WO
Inventors: Craig Allan Howard
Original assignee: Bencrai Pty Ltd
Priority date: 2003-12-17
Filing date: 2004-12-15
Publication date: 2005-06-30

Abstract

A pump (2) comprises a cylinder (4), a piston (10), a piston rod (12), a handle (14), a sleeve (16), and at least one opening (24) in the cylinder (4). The cylinder (4) has a free end (6) and a drive end (8). The piston (10) is housed for axial movement within the cylinder (4). The piston rod (12) is associated with the piston (10) and extends out of the cylinder drive end (8). The handle (14) is connected to the piston rod (12), and drives, via the piston rod (12), the piston (10) back and forth within the cylinder (4). The sleeve (16) has a clearance (18) around the cylinder (4) and extends axially between an open end (20) and a closed end (22), with the sleeve closed end (22) mounting the sleeve (16) to the cylinder (4) at or near the cylinder (4) drive end (8). The sleeve open end (20) is axially spaced apart from the closed end (22) towards the cylinder (4) free end (6). The at least one opening (24) in the cylinder (4) communicates the cylinder interior with the sleeve clearance (18).

Description

PISTON PUMP Field of the Invention The present invention relates to pumps and in particular to piston pump plungers. The invention has been developed primarily for use in dislodging toilet and drain blockages and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use. For example, it may also be used in applications such as a bilge pump, fuel transfer pump or in other pumping operations.

Background of the Invention Prior art pump plungers utilise a simple hand-held two-way piston pump to pump water back and forth in a blocked drain and thereby dislodge any blockage. A typical pump comprises a hand-held cylinder housing a piston, which is hand-driven via a piston rod and handle extending out of the cylinder from the piston, hi use, the water is sucked into the cylinder by drawing the handle away from the cylinder and then expelled therefrom by driving the handle back towards the cylinder. However, water often tends to seep between the piston and the cylinder, resulting in drain water accumulating on the piston rod side of the piston. This results in the water leaking out of the cylinder at the handle end, resulting in the user getting drain water over their hands, which is unpleasant. Moreover, the drain water is often very unhygienic and represents an infection risk. It is the object of the present invention to substantially overcome or ameliorate one or more of the disadvantages of the prior art, or to provide a useful alternative.

Summary of the Invention Accordingly, the present invention provides a pump comprising: a cylinder having free end and a drive end; a piston housed for axial movement within the cylinder; a piston rod associated with the piston, the piston rod extending out of the cylinder drive end; a handle connected to the piston rod, and being adapted for driving, via the piston rod, the piston back and forth within the cylinder; a sleeve having a clearance around the cylinder and extending axially between an open end and a closed end, the sleeve closed end mounting the sleeve to the cylinder at or near the cylinder drive end, the sleeve open end being axially spaced apart from the closed end towards the cylinder free end; and at least one opening in the cylinder communicating the cylinder interior with the sleeve clearance. In one arrangement, the sleeve extends approximately the width of an average human hand from the closed end to the open end. hi another arrangement, the sleeve extends at least 60% of the length of the cylinder. In a further arrangement, the sleeve is at least 295mm in length. The sleeve may comprise a first sleeve section mounted to the cylinder and a second sleeve section telescopically received in the first sleeve section. In one arrangement, the first sleeve section is at least 75mm in length and the second sleeve section extends at least 220mm from the first sleeve section. The sleeve clearance is preferably annular. The clearance preferably extends around the entire periphery of the cylinder. In one arrangement, the bore of the cylinder is approximately 50mm and the stroke is approximately 400mm. In another arrangement, the cylinder comprises a narrow section adjacent the drive end adapted to receive the piston rod and a broad section adjacent the free end adapted to house the piston. Preferably, the narrow section has an outer diameter of approximately 40mm and the broad section has a bore of approximately 80mm. In a preferred arrangement, the pump further comprises a seal attachment adapted to substantially seal a drain opening in communication with the interior of the cylinder. In one arrangement, the seal attachment is an outwardly tapering annular flange adapted to be pressed around a drain opening. hi another arrangement, the seal attacl ment comprises an extension pipe adapted at one end, to be connected to the cylinder free end and having, at the other end, an inwardly tapering seal substantially having the shape of a hollow truncated pyramid and being adapted to press fit into a drain opening. In a further arrangement, the seal attachment comprises an extension pipe adapted at one end, to be connected to the cylinder free end and having, at the other end, an annular seal extending radially from the extension pipe. In another arrangement, the pump may further comprise a T-piece attachment comprising a straight extension pipe adapted to be attached to the cylinder free end and a side outlet communicating with the extension pipe. In this arrangement, the pump may be used as a bilge pump or fuel transfer pump. In another arrangement, the pump may be used to pump water to a portable shower device. In another arrangement, the T-piece attachment may incorporate a filter for filtering a fluid. Brief Description of the Drawings Preferred embodiments of the invention will now be described, by way of examples only, with reference to the accompanying drawings in which: Fig. 1 is a side view of a first embodiment of a pump according to the invention; Fig. 2 is a cross sectional side view of the pump of Fig. 1; Fig. 3 is a partial cross sectional side view of the pump of Fig. 1; Figs. 4A-D are side views of the pump of Fig. 1, together with various attachments; Fig. 5 is a side view of the attachment shown in Fig. 4 A; Fig. 6 A is a central sectional view of the seal of the attachment of Fig. 5; Fig. 6B is a top plan view of the seal of Fig. 6 A; Fig. 7 is a side view of the attachment shown in Fig. 4B; Fig. 8 is a side view of the attachment shown in Fig. 4C; Figs. 9A-D are sectional views of the pump of Fig. 1, in different applications using different attachments; Fig. 10 is a side view of a second embodiment of a pump incorporating the attachment of Fig.7 and a filtration system; and Fig. 11 is a side view of the pump of Fig. 10 incorporating a filter.

Description of the Preferred Embodiments Figs. 1 to 3 show a first embodiment of a pump 2 according to the present invention. The pump 2 comprises a cylinder 4, having a free end 6 and a drive end 8, a piston 10 housed for axial movement in the cylinder 4, a piston rod 12 associated with the piston 10 and a handle 14 on the piston rod 12. The piston rod 12 extends from the piston 10, out of the drive end 8 of the cylinder 4 and terminates at the handle 14. The pump 2 further comprises a sleeve 16 mounted around the cylinder 4. The sleeve 16 has an annular clearance 18 around the cylinder 4 and extends axially between an open end 20 and a closed end 22. The sleeve closed end 22 mounts the sleeve 16 to the cylinder 4 near the cylinder drive end 8 and the sleeve open end 20 is axially spaced apart from the closed end 22 towards the cylinder free end 6. A number of openings 24 are provided in the wall of the cylinder 4 adjacent the closed end 22 of the sleeve 16, the openings 24 communicating the interior of the cylinder 4 with the sleeve clearance 18. The bore of the cylinder is approximately 50mm and the stroke of the piston 10 is approximately 400mm. In use, the pump 2 is held in two hands with one hand gripping the sleeve 16 and the other hand gripping the handle 14. Pulling the handle 14 away from the cylinder drive end 8 drives the piston 10 towards the cylinder drive end 8. This action sucks fluid into the cylinder 4 through the cylinder free end 6. Driving the handle 14 back towards the cylinder drive end 8 drives the piston 10 back towards the cylinder free end 6 expelling the fluid in the cylinder 4. During this operation, if any fluid in the cylinder 4 seeps between the piston 10 and the cylinder 4, it accumulates on the piston rod 12 side of the piston 10. Accordingly, as the piston 10 is drawn towards the cylinder drive end 8, the level of accumulated fluid 26 reaches the openings 24 and the fluid 26 drains from the cylinder 4 via the openings 24, into the clearance 18 and ultimately, out of the sleeve open end 20. Advantageously, the accumulated fluid 26 is able to drain from the cylinder 4 at a level below the portion of the user's hand and thus, without contacting the user's hands. This reduces the risk of the accumulated fluid 26 leaking from the cylinder 4 via the drive end 8 and contacting the user's hands. Figs. 4 to 7 show the pump 2 being used in different applications by attaching various attachments to the cylinder free end 6. Figs. 4A, 6A, 6B and 9B depict the first embodiment of the pump 2 with an elongate toilet attachment 28 comprising an exitension cylinder 30 and a seal 32. As shown in Fig. 9B, the seal 32 has the shape of a hollow truncated pyramid and is adapted to be pressed into a drain opening such as the drainage outlet of a toilet pan and substantially seal the drainage outlet in fluid communication with the interior of the cylinder 4. Figs. 4B and 7 depict pump 2 with a T-piece attachment 34 comprising an extension pipe 38 having a side outlet 40. In this application, fluid is pumped up through the extension pipe 38 and exits via the side outlet 40. Check valves (not shown) are provided in the T-piece at the extension pipe 38 and the side outlet 40. h the draw stroke, the valves are adapted to open the extension pipe 38 and close the side outlet 40, allowing fluid to be drawn into the cylinder 4 from the extension pipe 38. In the drive stroke, the valves are adapted to open the side oxitlet 40 and close the extension pipe 38, allowing fluid to be driven out through the side outlet 40. This embodiment is typically used as a bilge pump or fuel transfer pump. Figs. 4C, 8 and 9D depict the pump 2 with a pipe seal attachment 42 for clearing gullies. The attachment 42 comprises an extension pipe 48 and an annular seal 50, consisting of a rubber disc with a central bore. The size of the disc may vary depending on the application, however a typical size would be a diameter of 100mm or 150mm. In use, the extension cylinder 48 can be passed into a drain pipe beyond a drain junction to ensure substantially direct and exclusive communication between the blocked drain section and the interior of the cylinder 4. Figs. 4D, 9A and 9C depict pump 2 with a drain or sink seal attachment 44. As shown in Figs. 9A and 9C, when in use, the seal 44 is placed over the drain or sink opening forming a substantially sealed communication between the drain pipe and the interior of the cylinder 4. In a further application, the pump 2 with the T-piece attachment 34 is secured by a bracket over a bucket with the extension pipe 38 extending into the water. The side outlet 40 is connected to a portable shower reservoir such as an inflatable rubber bladder. Operation of the pump 2 transfers water from the bucket into the shower reservoir for subsequent use. Figs. 10 and 11 depict a second enibodiment of the pump 2', in which the cylinder 4' of the pump 2' comprises a narrow section 50 adapted to receive the piston rod 12' adjacent the drive end 8' and a broad section 52 adjacent the free end 6' for housing the piston 10'. This embodiment of the pump 2' enables a piston 10' of larger diameter than the first embodiment of the pump 2 to be housed in the broad section 52 while providing a narrow section 50 for gripping by the user. This provides a greater volume per stroke for the pump 2' compared to that of the first embodiment of the pump 2, whilst still allowing operation by a user with regular sized hands. A typical bore size for the broad section 52 is 80mm diameter, however, various bore sizes would be possible. The stroke is typically 300-400mm. This embodiment is particularly useful in applications where a large volume of fluid is required to be pumped. One application for pump 2' is in pumping and filtering water. As depicted in Fig. 10, the pump 2' includes the T-piece attachment 34 with the side outlet 40 connected to an auxiliary filtration system 56. The filtration system 56 comprises a primary tank 58 for receiving fluid from the side outlet 40 and a secondary tank 60 in fluid communication with the primary tanlc 58 via a filter 62. Fluid is first filtered in the primary tank 58 by a coarse filter 64 and then drains by gravity feed from the primary tank 58, through the filter 62, into the secondary tank 60. As the intake of the filter 62 is above the bottom surface of the primary tanlc 58, sludge can be drained from the bottom of the primary tanlc 58 via valve 66. Filtered fluid is drained from the secondary tank 60 via tap 68. Alternatively, the filter 62 can be directly incorporated into the T-piece attachment 34, as depicted in Fig. 11. The filter 62 may be incorporated into the extension pipe 38, so that fluid is filtered as it is drawn through the extension pipe 38. Alternatively, the filter 62 may be attached to the side outlet 40 (depicted in phantom), so that fluid is filtered as it is discharged from the side outlet 40. These applications are particularly useful, for example, in pumping river water for drinking purposes. Table of displacement per 50mm of piston stroke for different size cylinder bores from 30mm to 150mm.

Length of piston stroke in 50mm increments

30mm 35mm 40mm 45mm 50mm 55mm 60mm 65 mm 80mm 100mm 150mm

(Displacement values shown in cubic centimeters)

The above table compares the work rate of pumps made with different size bores and different stroke lengths and shows the volume of water that would be displaced by a piston stroke (of the given length at the top of the table) in a pump with an internal bore (of the given diameter at the side of table). As water does not compress, and assuming that a good seal has been achieved at the point of connection of the pump to the plumbing system, the amount of water that is displaced by the piston stroke is the same amount of displacement caused at the point of a blockage in the pipe. The table also shows an approximate translation from the displacement caused by the stroke of the piston to how much displacement is caused in a pipe of a different diameter at the point of a blockage. For example, a pump with a bore of 50mm and a stroke of 30mm would cause a displacement of 589 cubic centimeters of water with each stroke which would cause between 50mm and 100mm of displacement of the entire pipe bore at the point of a blockage in a sewer pipe with a diameter of 100mm. The pressure that is applied to the blockage is directly proportional to the pressure applied by the user, and varies to some extent with every different user. Accordingly, the amount of displacement would become the main concern governing the design of pump with a particular performance in mind. Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in other forms.

Claims

Claims:

1. A pump comprising: a cylinder having free end and a drive end; a piston housed for axial movement within the cylinder; a piston rod associated with the piston, the piston rod extending out of the cylinder drive end; a handle connected to the piston rod, and being adapted for driving, via the piston rod, the piston back and forth within the cylinder; a sleeve having a clearance around the cylinder and extending axially between an open end and a closed end, the sleeve closed end mounting the sleeve to the cylinder at or near the cylinder drive end, the sleeve open end being axially spaced apart from the closed end towards the cylinder free end; and at least one opening in the cylinder communicating the cylinder interior with the sleeve clearance.

2. The pump as claimed in claim 1, wherein the sleeve extends approximately the width of an average human hand from the closed end to the open end.

3. The pump as claimed in claim 1, wherein the sleeve extends at least 60% of the length of the cylinder from the closed end to the open end.

4. The pump as claimed in claim 1, wherein the sleeve is at least 295mm in length from the closed end to the open end.

5. The pump as claimed in any one of the preceding claims, wherein the sleeve comprises a first sleeve section mounted to the cylinder and a second sleeve section telescopically received in the first sleeve section.

6. The pump as claimed in claim 5, wherein the first sleeve section is at least 75mm in length and the second sleeve section extends at least 220mm from the first sleeve section.

7. The pump as claimed in any one of the preceding claims, wherein the sleeve clearance is annular.

8. The pump as claimed in any one of the preceding claims, wherein the clearance extends around the entire periphery of the cylinder.

9. The pump as claimed in any one of the preceding claims,, wherein the bore of the cylinder is approximately 50mm and the stroke is approximately 400mm.

10. The pump as claimed in any one of the preceding claims, wherein the cylinder comprises a narrow section adjacent the drive end adapted to receive the piston rod and a broad section adjacent the free end adapted to house the piston.

11. The pump as claimed in claim 10, wherein the narrow section has an outer diameter of approximately 40mm and the broad section has a bore of approximately 80mm.

12. The pump as claimed in any one of the preceding claims, wherein the pump further comprises a seal attacliment adapted to substantially seal a drain opening in communication with the interior of the cylinder.

13. The pump as claimed in claim 12, wherein the seal attachment is an outwardly tapering annular flange adapted to be pressed around the drain opening.

14. The pump as claimed in claim 12, wherein the seal attachment comprises an extension pipe adapted at one end, to be connected to the cylinder free end, and having, at the other end, an inwardly tapering seal substantially having the shape of a hollow truncated pyramid and being adapted to press fit into the drain opening.

15. The pump as claimed in claim 12, wherein the seal attachment comprises an extension pipe adapted at one end, to be connected to the cylinder free end, and having, at the other end, an annular seal extending radially from the exitension pipe.

16. The pump as claimed in any one of claims 1 to 11, Λvherein the pump further comprises a T-piece attachment comprising a straight extension pipe adapted to be attached to the cylinder free end and a side outlet communicating with the extension pipe.

17. The pump as claimed in claim 16, wherein the T-piece attachment incorporates a filter for filtering a fluid.

18. A pump substantially as described herein with reference to: Figs. 1 to 3; any one of Figs. 4A to 9D; Fig. 10; or Fig. 11 of the accompanying drawings.