AU2002240729B2 - Displacement pump and ancillary equipment - Google Patents

Description

WO 02/081917 PCT/AU02/00375 Displacement Pump and Ancillary Equipment FIELD OF THE INVENTION The present invention relates to displacement pumps and, in particular, to displacement pumps which are able to be utilised for the pumping of slurries, preferably, but not exclusively in the long distance transportation of minerals by pipeline. The present invention also relates to ancillary equipment such as dampers and valves.

BACKGROUND ART In the pumping of slurries, various of types of pumps are known and Australian Patent No. 719,094 (WO 99/08761) disclosed various types of pump which are able to be used. Of these, the displacement pump offers many advantages in that it is able to be connected in line, the pump chamber can be arranged to be offset so as to be naturally scavenging, and the use of the diaphragm enables a very large displacement to be achieved. However, in a conventional diaphragm pump, the diaphragm in addition to being flexible is also elastic and is normally stretched during the pumping action. This has the disadvantage in that the material tends to rupture during use. Also, in general, the tougher the material the less likely it is to rupture but the more difficult it is to elastically deform from its original state. Thus there is an inherent conflict in finding a material suitable for use as the pump diaphragm. Furthermore, in order to achieve high throughput rates, it is necessary to apply a substantial force to the diaphragm in order to move it. But, in general, such high forces and elastically deformable diaphragms are not compatible.

OBJECT OF THE INVENTION The object of the present invention is to provide a displacement pump and ancillary equipment which, by virtue of its construction, is better suited to the operational demands placed on the equipment than the above described prior art.

WO 02/081917 PCT/AU02/00375 SUMMARY OF THE INVENTION In accordance with a first aspect of the present invention there is disclosed a displacement pump comprising a frusto-conical backstop having an opening at its apex, a concentric and opposed frusto-conical wall leading into a valve chamber having a inlet valve and an outlet valve, a flexible membrane extending across and being sealingly sandwiched between the rim of said backstop and the rim of said wall, and a reciprocation means connected to the backstop side of said membrane to alternatively move said membrane towards and away from said valve chamber, characterised in that said membrane is substantially conical having a peripheral region butting said backstop, is both radically and circumferentially reinforced with a plurality of reinforcing cables, and is at least partially inverted being rolled over about a generally annular region concentric with said wall and backstop, the diameter of said annular region increasing and decreasing with said alternating movement whereby said membrane changes its configuration without changing its size.

In accordance with a second aspect of the present invention there is disclosed a displacement pump comprising a cap, an inverted frusto-conical wall opposed to said cap and leading into a valve chamber having an inlet valve and an outlet valve, and a flexible membrane extending across, and being sealingly sandwiched between, the rim of said cap and the rim of said wall, characterised in that a volume changeable medium is located between said cap and membrane and is actuatable to alternatively move said membrane towards and away from said valve chamber, and said membrane is substantially conical, and is at least partially inverted being rolled over about a generally annular region concentric with said wall, the diameter of said annular region increasing and decreasing with said medium actuation whereby said membrane changes its configuration without changing its size.

In accordance with a third aspect of the present invention there is disclosed damper for use with slurry pipelines and the like, said damper comprising a generally conical cap, a concentric and opposed frusto-conical wall leading into an opening WO 02/081917 PCT/AU02/00375 forming an inlet and an outlet for said damper, a flexible membrane extending across, and being sealingly sandwiched between, the rim of said cap and the rim of said wall, characterised in that said membrane is substantially conical having a peripheral region abutting said cap, and is at least partially inverted being rolled over about a generally annular region concentric with said wall and cap, the diameter of said annular region increasing and decreasing in response to changing pressure at said opening whereby said membrane changes its configuration in response to said pressure changes without changing its size.

In accordance with a fourth aspect of the present invention there is disclosed a valve suitable for slurry pumping, slurry pipelines, and the like, said valve comprising a pair of in line valve seats each inclined to the direction of slurry movement and communicating with a valve chamber, a flap located on the downstream side of each said valve seat and mounted for pivotal movement relative to said valve seat about a fixed axis of rotation to open and close said seat, characterised in that said pivotal mounting comprises a pair of spaced apart flexible cables whereby said flap can twist about a twist axis substantially normal to said axis of rotation and located intermediate said spaced apart cables, and said flap can move towards and away from said valve seat into and out of a plane substantially parallel to said valve seat.

BRIEF DESCRIPTION OF THE DRAWINGS The embodiments of the present invention will now be described with reference to the drawings in which: Fig. 1 is a longitudinal cross-sectional view of the displacement pump of the first embodiment illustrating the suction stroke, Fig. 2 is a view similar to Fig. 1 but illustrating the compression stroke, Fig. 3 is a view similar to Figs. 1 and 2 but illustrating a second embodiment of the displacement pump of the present invention, Fig. 4 is a plan view of a valve flap used in the embodiments of Figs. 1 and 2, Fig. 5 is a side elevational view of the preferred arrangement of valve seat and valve flap, the valve being in the closed position, WO 02/081917 PCT/AU02/00375 Fig. 6 is a view similar to Fig. 5 but showing the valve seat in the open condition, Fig. 7 is a view similar to Fig. 1 but illustrating a damper of the preferred embodiment at an instant of high pressure in the pipeline, Fig. 8 is a view similar to Fig. 7 but illustrating the arrangement at an instant of low pressure in the pipeline, Fig. 9 is an enlarged view similar to Figs. 1, 2, 3, 7 and 8 but illustrating the extreme positions able to be adopted by the membrane, Fig. 10 is a vertical cross-sectional view taken of a mandrel showing the construction technique required to fabricate the membrane, Fig. 11 is a plan view of the mandrel of Fig. 10 showing the sequence of laying the reinforcing cables, Fig. 12 is a plan view showing the initial securing of the cable to the first pin, Fig. 13 is a similar view to Fig. 12 showing the termination of the first and last strands of cable, Fig. 14 is a vertical and radial cross sectional view showing the circumferential reinforcement of the membrane, Fig. 15 is a vertical cross-sectional view through the central hub of the membrane during laying of the cables, and Fig. 16 is a view similar to Fig. 14 but taken at 900 thereto.

DETAILED DESCRIPTION As seen in Fig. 1, the displacement pump 1 of the preferred embodiment has an inlet 2 and an outlet 3 which define a direction of flow. Inclined to the direction of flow, and preferably so inclined by 45, is an inlet valve seat 4 and an outlet valve seat Mounted above the seats 4, 5 are corresponding valve flaps 6, 7.

Between the two valve seats 4, 5 is an opening 9 which leads into a frusto-conical wall 10 which has a rim 11. Concentric with the wall 10 but opposed thereto is a frustoconical backstop 12 which as a similar rim 13. The cone angle of both the wall 10 and backstop 12 is preferably 45' Sandwiched between the rims 11, 13 is a flexible diaphragm 15 which is able to be reciprocated by any convenient means such as an WO 02/081917 PCT/AU02/00375 electric motor 17 and linkage 18. The wall 10 is supported by a tube 19 which is able to be mounted in-line with a slurry pipeline (not illustrated).

During the suction stroke illustrated in Fig. 1, the membrane of diaphragm moves away from the opening 9 thereby reducing pressure within the tube 19, As a consequence, the outlet valve flap 7 closes and the inlet valve 6 opens so that fluid (either a liquid or a gas) enters the inlet 2 and passes into the opening 9. During the compression stroke illustrated in Fig. 2, the membrane 15 is moved towards the opening 9 thereby closing the inlet flap 6 and opening the outlet flap 7 to eject fluid from the tube 19.

A second embodiment of a pump 20 is illustrated in Fig. 3. Like components in Fig. 3 are numbered in the same manner as like components in Figs. 1 and 2. The main difference with the embodiment of the pump 20 in Fig. 3 is that the frusto-conical backstop 12 is replaced by a hemispherical cap 22 and the region between the cap 22 and the diaphragm 15 is filled with a medium 24 the volume of which is changeable so as to either draw the diaphragm 15 upwardly or drive the diaphragm 15 downwardly. Such a medium 24 is preferably a polymer gel. Such gels are known in the medical field where attempts have been made to fabricate artificial muscles therefrom. Applying a positive or negative voltage to the gel causes the gel to expand or contract or changes in volume in the order of up to one thousand fold have been reported. The preferred material selected from the group consisting of ionic polymer gels, dielectric elastomers, and products known as HYDROGEL or NAFION-117.

It will be seen from a comparison of Figs. 1 and 2 with Fig. 3 that the essential difference in the embodiments is the driving mechanism for the pump. The pump of both embodiments operates the same way as far as pumping the fluid past the inlet and outlet valves. In Fig. 3 the diaphragm 15 is illustrated in each of its extreme positions.

Details of the flap valve used in both embodiments of Figs. 1-3 are illustrated in more detail in Figs. 4-6. As seen in Fig. 4, the flap 6, 7 is preferably formed from polyurethane moulded over a stainless steel mesh 26. The flaps 6, 7 are pivoted by WO 02/081917 PCT/AU02/00375 means of a single cable 27 fabricated from twisted stainless steel filaments and arranged in a U-shaped configuration having two arms 28, 29 and a central bight 30. The bight defines a pivot axis 31 about which the flaps 6, 7 can pivot as indicated by arrows in Figs.

and 6. In addition, the two arms 28, 29 permit the flap 6, 7 to twist about a twist axis 32. Furthermore, as indicated in Fig. 5, the flaps 6, 7 can move into and out of a position in a plane parallel to the valve seat. This movement is illustrated in phantom in Fig. The consequence of the arrangements illustrated in Figs. 4-6 is that the valve formed therefrom is able to pass through it particles having a maximum dimension substantially equal to the internal diameter to the inlet 2 and outlet 3 (ie essentially the internal diameter of the pipeline). In the event that when the valve is closing, a particle is trapped between the flap 6, 7 and the valve seat 4, 5, then the valve only partially closes during that particular stroke. However, on the next stroke of the pump, the valve will almost certainly clear because of the large displacement volume of the pump. In this connection it is desirable to adjust the buoyancy of the flap 6, 7 so as to be of a density which is approximately equal to the liquid being pumped. If desired, for example, the inlet flap 6 can be made slightly buoyant whilst the outlet flap 7 can be made slightly more dense so that the inlet valve is normally open and the outlet valve is normally closed in the absence of any operation of the pump or vice versa if that is preferred depending upon the application.

Turning now to Figs. 7 and 8, a damper 40 is illustrated which is supported above a tube 49 and has a frusto-conical wall 10 with rim 11 as before. Rather than a frustoconical backstop at 12, the damper 40 has a conical cap 42 with rim 13. If desired, a pressure gauge 43 can be mounted in the conical cap 42. The diaphragm 15 is essentially as before and preferably carries a small water load 44 to bias the diaphragm downwardly.

The diaphragm 15 moves so that pressure on each side of the diaphragm 15 is equal. As indicated in Fig. 7, with fluctuating pressure in the pipeline (and hence in the WO 02/081917 PCT/AU02/00375 tube 49) fluid is drawn into the space below the diaphragm 15 or ejected therefrom and thus damps any pressure fluctuations appearing in the tube 49.

The preferred form of fabrication of the diaphragm or membrane 15 will now be described with reference to Figs. 9-16. The diaphragm 15 preferably takes the form of a hub 50 which is interconnected to the periphery of the diaphragm 15 by means of radial cables 51 which are interwoven with circumferential cables 52 and embedded in an elastomer 53 such as vulcanised rubber, polyurethane or the like. The cables are preferably formed from stainless steel but aramid fibres such as KEVLAR (Registered Trade Mark) or other filaments such as from the motor tyre fabrication arts, can also be used.

The hub 50 is provided with a central stalk 55 to which the linkage 18 (Figs. 1 and 2) is connected. The stalk 55 is provided with an inner dome 56 and an outer dome 57.

In order to fabricate the diaphragm 15, the hub 50, initially without its outer dome 57, is centrally located within a conical mandrel 59 as seen in Fig. 10. The mandrel 59 is provided with 36 pegs 60 extending around its outer periphery. As seen in Fig. 15, the inner dome 56 is initially provided with two pins 61.

As seen in Figs. 11-13, the leading end of the radial cable 51 is made fast temporarily around the first peg 160 and thereafter led around pin 61 and over the inner dome 56 and then passed around peg 260. From there the cable 51 is again passed around the pin 61 and over the inner dome 56 to be passed around peg 360, and so on.

The final leg of the cable 51 is passed around the peg opposite 160, over the top of the cables lying against the inner dome 56 and back to peg 160 where the two free ends are made fast by means of a copper ferrule 63 (Fig. 13). Thereafter, the circumferential cables 52 can be individually woven through the radial cables 51 as indicated schematically in Fig. 11 and in more detail in Fig. 14.

The tension in the radial cables 51 can be adjusted by means of a ring 64 (Fig. and then the outer dome 57 can be placed over the pins 61 and welded thereto. If desired, WO 02/081917 PCT/AU02/00375 the outer dome can be internally grooved to receive the last portion of the cable 51 and can also be crimped to the inner dome 56. Finally, the ring 64 is removed and the protruding portions of the two pins ground flush with the outer dome 57. Next the cables 51, 52 and hub 50 are encased in elastomeric material and cured if necessary so as to complete the fabrication of the diaphragm. Removal of the pegs 60 enables the diaphragm to be removed from the mandrel 59.

The above described procedure results in a conical diaphragm or membrane which has a central hub 50 and a periphery which is able to be sealingly held between the rims 11, 13 of Figs. 1-3. As best seen in Fig. 9, although as fabricated the diaphragm is conical, the centre hub 50 is pushed downwardly so as to invert the central portion of the diaphragm. As indicated in phantom in Fig. 9, the boundary between the inverted central cone and the upright exterior partial cone is defined by an annular region 66 the diameter of which increases and decreases according to the movement of the diaphragm In the embodiment of Fig. 3 and the damper of Figs. 7 and 8, the pressure applied to opposite sides of the diaphragm 15 is nearly equal. Therefore it is not essential that the diaphragm 15 in these applications be reinforced. However, in the embodiment of Figs. 1 and 2, atmospheric pressure is applied to one side of the diaphragm 15 whilst the other has the pipeline pressure applied thereto. The rolling action of the annular ring 66 ensures that the forces applied to the diaphragm 15 are adequately resisted by the cables 51, 52. For example, the reinforcing layer of cables within the diaphragm 15 need not be restricted to a single layer, instead multiple layers can be used if desired.

The foregoing describes only some embodiments of the present invention and modifications of those skilled in the art, can be made thereto without departing from the scope of the present invention.

The term "comprising" (and its grammatical variations) as used herein is used in the inclusive sense of "including" or "having" and not in the exclusive sense of "consisting only of'.

Claims (24)

1. A displacement pump comprising a frusto-conical backstop having an opening at its apex, a concentric and opposed frusto-conical wall leading into a valve chamber having a inlet valve and an outlet valve, a flexible membrane extending across and being sealingly sandwiched between the rim of said backstop and the rim of said wall, and a reciprocation means connected to the backstop side of said membrane to alternatively move said membrane towards and away from said valve chamber, characterised in that said membrane is substantially conical having a peripheral region butting said backstop, is both radically and circumferentially reinforced with a plurality of reinforcing cables, and is at least partially inverted being rolled over about a generally annular region concentric with said wall and backstop, the diameter of said annular region increasing and decreasing with said alternating movement whereby said membrane changes its configuration without changing its size.

2. The pump as claimed in claim 1 wherein said reinforcing cables extend radially from a central hub and extend circumferentially by being woven between said radial reinforcing cables.

3. The pump as claimed in claims 1 or 2 wherein said membrane is fabricated from an elastomer with said reinforcing cables embedded therein.

4. The pump as claimed in any one of claims 1-3 wherein an opening between said frusto-conical wall and said valve chamber is offset relative to the longitudinal axis of said frusto-conical wall to thereby provide a scavenging action for said valve chamber. A displacement pump comprising a cap, an inverted frusto-conical wall opposed to said cap and leading into a valve chamber having an inlet valve and an outlet valve, and a flexible membrane extending across, and being sealingly sandwiched between, the rim of said cap and the rim of said wall, characterised in that a volume changeable medium is located between said cap and membrane and is actuatable to alternatively move said membrane towards and away from said valve chamber, and said membrane is substantially conical, and is at least partially inverted being rolled over about a generally annular region concentric with said wall, the diameter of said annular region increasing and decreasing with said medium actuation whereby said membrane changes its configuration without changing its size.

WO 02/081917 PCT/AU02/00375

6. The pump as claimed in claim 5 wherein said medium comprises a polymer which is electrically actuated.

7. The pump as claimed in claim 5 or 6 wherein said medium is selected from the group consisting of ionic polymer gels, dielectric elastomers, HYDROGEL and NAFION-117.

8. The pump as claimed in any one of claims 5-7 wherein said membrane is formed from an unreinforced elastomer.

9. The pump as claimed in any one of claims 5-7 wherein said membrane is formed from a reinforced elastomer.

A damper for use with slurry pipelines and the like, said damper comprising a generally conical cap, a concentric and opposed frusto-conical wall leading into an opening forming an inlet and an outlet for said damper, a flexible membrane extending across, and being sealingly sandwiched between, the rim of said cap and the rim of said wall, characterised in that said membrane is substantially conical having a peripheral region abutting said cap, and is at least partially inverted being rolled over about a generally annular region concentric with said wall and cap, the diameter of said annular region increasing and decreasing in response to changing pressure at said opening whereby said membrane changes its configuration in response to said pressure changes without changing its size.

11. The damper as claimed in claim 10 wherein said membrane is formed from a reinforced elastomer.

12. The damper as claimed in claim 10 wherein said membrane is formed from an unreinforced elastomer.

13. The damper as claimed in any one of claims 10-12 wherein a liquid ballast is introduced into the space between said cap and membrane.

14. The damper as claimed in claim 13 wherein said liquid ballast lies on said membrane.

The damper as claimed in any one of claims 10-14 wherein said conical cap and said frusto-conical wall each have approximately the same cone angle.

16. The damper as claimed in claim 15 wherein said cone angle is approximately

17. A valve suitable for slurry pumping, slurry pipelines, and the like, said valve comprising a pair of in line valve seats each inclined to the direction of slurry movement and communicating with a valve chamber, a flap located on the downstream side of each said valve seat and mounted for pivotal movement relative to said valve seat about a fixed axis of rotation to open and close said seat, characterised in that said pivotal mounting comprises a pair of spaced apart flexible cables whereby said flap can twist about a twist axis substantially normal to said axis of rotation and located intermediate said spaced apart cables, and said flap can move towards and away from said valve seat into and out of a plane substantially parallel to said valve seat.

18. The valve as claimed in claim 17 wherein said pair of cables comprise opposite ends of the same cable.

19. The valve as claimed in claim 17 or 18 wherein each flap is moulded from polyurethane reinforced with stainless steel mesh.

The valve as claimed in any one of claims 17-19 wherein the density of the or each flap is approximately that of the density of the liquid passing through said valve.

21. The valve as claimed in any one of claims 17-20 and having a displacement pump mechanism located between said pair of valve seats which form the inlet and outlet respectively of said displacement pump.

22. A displacement pump substantially as herein described with reference to Figs. 1 and 2, or Fig. 3 of the drawings.

23. A damper for use with slurry pipelines and the like, said damper being substantially as herein described with reference to Figs. 7 and 8 of the drawings.

24. A valve suitable for slurry pumping, slurry pipelines, and the like, said valve being substantially as herein described with reference to Figs. 4-6 of the drawings. A method of fabricating a substantially conical reinforced membrane, said method being substantially as herein described with reference to Figs. 9-16 of the drawings. Dated this 9 th day of September 2003 PUMPING SYSTEMS TECHNOLOGIES PTY LIMITED By: FRASER OLD SOHN