WO1997029285A1

WO1997029285A1 - Peristaltic pump mechanism

Info

Publication number: WO1997029285A1
Application number: PCT/AU1997/000069
Authority: WO
Inventors: Allan Richard Jones
Original assignee: Allan R Jones Technologies Pty. Limited
Priority date: 1996-02-09
Filing date: 1997-02-10
Publication date: 1997-08-14

Abstract

A peristaltic pumping mechanism (50) comprises a flexible fluid pumping element (55) arranged in a partially circular path and being sandwiched between two discs (51) and coupled to the respective discs (51). Motion is imparted to both discs (51) to reduce and increase the spacing between adjacent points on the circumference of the discs (51) and thereby impart a circular rolling contact to the pumping element (55) producing a peristaltic pumping action. In a second embodiment the pumping element (55) is sandwiched between a movable helically shaped disc and a complementary shaped pumping bed.

Description

PERISTALTIC PUMP MECHANISM TECHNICAL FIELD The present invention relates to peristaltic pumps and more particularly to a mechanical pump mechanism akin to that disclosed in my published International patent application W095/11383. the contents of which are incorporated herein by reference.

BACKGROUND ART The arrangements shown by Figs 4-9 of the aforementioned International patent application employ the circular rolling contact of a pumping disc which imparts a rolling contact or peristaltic pumping action to a pumping tube or element placed on a circular path under the rotary action of a central armature or other means acting on the circular perimeter of the discs. That cyclic circular rolling contact sequentially compresses or closes and then opens the pumping element against a pump bed or between pairs of discs around a circular path to impart a peristaltic pumping action to the pumping element and is hereinafter referred to as a peristaltic pumping action of the kind described.

DISCLOSURE OF INVENTION In a first aspect of the present invention the functionality of the aforementioned mechanical pumping arrangement is retained but in that there are two discs adapted to interact with each other and comprising a pumping element sandwiched therebetween.

In accordance with the first aspect of the present invention there is provided a pumping mechanism for providing a peristaltic pumping action of the kind described comprising a flexible fluid transmitting pumping element arranged in a substantially planar at least partially circular path, said pumping element having an inlet at one end and an outlet at its opposite end and being sandwiched between two discs and coupled to the respective discs around curved paths so as to move in sympathy with the relative motion of the discs by moving to reduce the fluid transmitting cross-sectional area of the pumping element as adjacent points on the discs move toward each other and to increase the fluid transmitting cross-sectional area of the pumping element as those adjacent points move away from each other, and wherein motion is imparted to both discs to reduce and increase the spacing between adjacent points on the circumference of the discs such that when a pair of adjacent points are at their closest the diametrally opposed adjacent points of the two discs are maximally separated and further wherein the spacing between the discs progressively varies circumferentially of the discs to impart a peristaltic pumping action to the pumping element.

Preferably, the motion imparted to the discs in pumps of this aspect of the invention is achieved by a rotatable armature passing through the centre of the discs wherein the armature comprises a set of at least one radially projecting arm in contact with each disc but could be two diametrally opposed axially displaced radially projecting arms in contact with each disc or most preferably a set of three circumferentially spaced apart radially projecting arms in contact with each disc in a similar manner to that as shown in Figs. 4-9 of W095/11383. For each set of arms of a three arm set. two arms have axes in a common radial plane of the armature with the other arm being axially displaced relative to the two arms. Each disc then being mounted to the armature by having the two arms on one side of the disc and the other arm on the other side of the disc.

The pumping element can take a form as shown in Figs. 4-9 of my above referenced published International patent application or as clamped together separate circular flat sheets of flexible material with a substantially rigidly formed inlet and outlet openings which are not acted upon by the relative motion between the discs due to shaped surfaces or detents on the discs adjacent the inlet and outlet openings. Preshaped or planar pumping elements should be suitable for use with the invention.

In another embodiment the armature incorporates an eccentric camming surface which assists opening of the pumping element during separation of the discs. The cam surface being oriented on the armature to provide a complementary opening action to the pumping element relative to the opening action achieved by the radially projecting arms as described above.

In a still further embodiment the discs are closed by compressing rollers acting against the outer edge of respective discs in an opposed manner while the discs are able to swivel toward and away from each other at their perimeters by being centrally mounted on swivel bearings on a common central axis.

Another embodiment provides a positive closing and opening action to the discs by having the discs mounted on swivel bearings as well as compressing rollers as mentioned above but in this case there are also included rollers acting on the inner or opposed disc faces to separate the discs. Those inner face rollers being diametrally opposed to the compressing rollers. In this and the preceding embodiment the motion of the discs is achieved by mechanical action around their perimeters rather than via rotation of a central armature.

In the present invention the functionality of the aforementioned known mechanical pumping arrangements are retained but in this second aspect of the invention there is at least one disc acting on a pumping element where the part of that disc acting on the element takes the form of at least a portion of a helical spiral. In the case of a single disc pump of this aspect of the invention the disc acts against the pumping element by squeezing the element between the disc and a fixed pump bed and where the pump bed may be shaped as a complementary spiral surface.

In embodiments where there are, say, two spiral formed discs arranged to interact in the manner of the discs as provided for in the first aspect of the invention, then each of those discs is only required to oscillate to a part of the extent of a spiral disc that moves against a fixed pumping bed to achieve the same pumping effect.

In both aspects of the present invention it is possible to arrange multiple disc pumps in side by side relation wherein each disc functions to interact with pumping elements on each side of the disc. The end discs of the stack can interact with fixed pumping beds.

Preferably, the motion imparted to the discs in pumps of the second aspect of the invention is achieved by a rotatable armature passing through the centre of the discs in the manner shown in the above referenced applications or by means of rollers or rotating drums.

BRIEF DESCRIPTION OF THE DRAWINGS With preferred embodiments, pumps of this invention allow for a 360° pumping cycle in conjunction with the provision of an inlet and outlet at the same tangent to the pumping disc.

Embodiments of both aspects of the present invention will now be described by way of example with reference to the accompanying drawings, in which :-

Fig. 1 shows an exploded perspective view of a first embodiment of a peristaltic pump arrangement in accord with the first aspect of the present invention; Fig. 2 is a cross-sectional view of the embodiment of Fig. 1 in its assembled form in one orientation;

Fig. 3 is the same view as Fig. 2 but with the discs in the opposite orientation; Fig. 4 is a schematic sectional view of a second embodiment;

Fig. 5 is a schematic sectional view of a third embodiment; Fig. 6 is an exploded view of the components of a double spiral disc arrangement in accord with an embodiment of the second aspect of the present invention; Fig. 7 is a cross-sectional view of the embodiment of Fig. 6 within a container or casing;

Fig. 8 is a plan view of Fig 7;

Fig. 9(a) is a cross-sectional view at the perimeter of the pump of Fig. 6 where the inlet and outlet pass each other; Fig. 9(b) is the same view as Fig. 9(a) but where the inlet and outlet are compressed by the discs;

Fig. 10 is a perspective view of the essential components of a single spiral pumping disc pump in spaced apart relation;

Fig. 11 is an exploded perspective view of a further embodiment in accord with the second aspect of the present invention;

Fig. 12 is a perspective view of a still further embodiment of the second aspect of the invention being similar to the embodiment of Fig. 6;

Fig. 13 is an exploded prospective view of yet another embodiment of the second aspect of the invention; Fig. 14 is an exploded perspective view of major components of a modification of the embodiment of Fig. 13;

Figs. 15(a) and (b) are cross-sectional views of the embodiment of Fig.13 with the pumping disc oriented at opposite phases during a pumping operation; and Fig. 16 is a schematic plan view showing the layout of discreet pumping chambers in accord with the embodiments of Figs. 13 and 14.

BEST MODES The pump 10 of the first embodiment as shown in Figs. 1-3 of the drawings comprises an outer casing having two halves 11 which contain in the assembled condition two movable discs 12 held by armature 13 between respective sets of radially projecting conical rollers 13 and 14. Each set comprises a pair of rollers 13 which have their axes in a common transverse plane of armature 15 and a third roller 14 axially offset on the armature and with its axis in a different transverse plane.

The two rollers 13 contact a common face of disc 12 while roller 14 contacts the other face of its respective disc 12.

Pumping element 16 is sandwiched between the discs 12 and coupled to those discs via upstanding projections 17 as is more clearly shown in Figs. 2 and 3.

Pumping element 16 is formed from two toroidal planar sheets of flexible material which are clamped together at their outer perimeter between flanges 18 of the two casing halves 11. The internal perimeter of the planar pumping element 16 being clamped together between rings 19.

The centre of armature 15 incorporates a camming surface 20. The function of camming surface 20 can be clearly seen in Figs. 2 and 3 where it is oriented to assist opening of the pumping element 16 by pushing rings 19 laterally of the armature during opening separation of discs 12 as shown to the left of Fig. 2 and to the right of Fig. 3 as viewed in those drawings.

The peristaltic pumping action of the embodiment of Figs. 1-3 is achieved by rotation of armature 15 which in conjunction with contact between roller sets 13, 14 and respective discs 12 imparts a peristaltic pumping action to pumping element 16.

Inlet 21 and outlet 22 are not acted upon by the motion of discs 12 and are accommodated in complementary recesses 23 provided in flanges 18 of the casing halves 11 and detents 24 in discs 12. In a further embodiment (not shown), the casing 11 is formed so as to be flexed axially of the armature 15 while containing water so as to form a water box. In this embodiment the flexure of the casing halves 11 in conjunction with the contained water is adapted to provide an hydraulic assist to the opening of the pumping element 16 during operation of the pump 10 in a manner that is understood in the art.

In the embodiment of Fig. 4 a pump 30 comprises two movable discs 31 mounted on several bearings 32 supported on central shaft 33.

Tubular pumping element 34 is positioned around the perimeters of discs 31 and sandwiched between those discs. The peristaltic action applied to element 34 is achieved by rotation of rollers 35 on gear wheels 36 driven by pinions 37 via drive shaft 38. Gear wheels 36 being rotatably mounted on shaft 33.

Rollers 35 are located in opposed relation to each other as shown in

Fig. 4 to move the perimeters of discs 31 toward each other and compress element 34. Side thrust applied to gear wheels 36 by the resistance of element 34 to being compressed as shown is countered via a load bearing rolling contact between each roller 35 and a circular path on the inner face of a pump casing 39 which shown only in part at the bottom right hand corner of Fig. 4. As can be seen from the sketch of Fig. 4 rotation of drive shaft 38 and pinions 37 drives gear wheels 36 in unison so that rollers 35 move around adjacent locations of opposed discs 31 to compress element 34 in circular fashion as discs 31 swivel on bearings 32. No rotation of discs 31 occurs while they move toward and away from each other under the action of rollers 35 to impart a peristaltic pumping action to element 34.

In the pump 40 of the embodiment of Fig. 5 a pair of discs 41 are mounted on swivel bearings 42 in similar manner to the arrangement of the embodiment of Fig. 4.

In this embodiment a circular compression and expansion of element 43 between discs 41 is achieved by rotation of two drum halves 44 by rotation of the central shaft 45.

Rotation of central shaft 45 also effects rotation of crown wheel 46 and the pinion gear 47 to impart a substantially non-slip rolling contact between rollers 48, 49 and respective discs 41. Figs. 6-9 depict a double acting spiral disc arrangement which contrasts with a single disc form of pump as depicted in a prior art form in

Figs 4-8 of W095/11383.

In Figs. 6-9, the form of peristaltic pump 50 comprises spaced apart spiral discs 51 each with a planar centre section 52 which interacts with the rollers 53 mounted on armature 54.

The interaction between armature 54, rollers 53 and planar sections

52 is depicted in Fig 2 and that mode of operation is clearly described in the above referenced earlier filed applications and need not be further discussed as those disclosures have been incorporated herein. The helical spiral form of discs 51 is such that the pumping tube or element 55 of any suitable shape is oriented so that the inlet and outlet to the pump occurs in overlapping relation at the adjacent free ends of each spiral 51 which fit in complementary relation to each other with pumping element 55 sandwiched therebetween. Pumping element on tube 55 may be freely disposed between discs 51 or fixed to those discs after the manner shown in Figs. 1-3. There is a radial displacement between the outer extremities of the free ends of each spiral 51 to facilitate the radial displacement between the inlet and outlet sides of element 55. That displaced arrangement is best seen in the plan view of Fig 3.

Radially projecting tabs 56 with through bores 57 are adapted to fit over fixed posts to retain the relative relation between two spiral discs 51 during peristaltic pumping action under the motion applied by rollers 53 during rotation of armature 54 so as to prevent rotation of the discs.

As shown in Figs. 6 and 8, the pumping element 55 in a double acting spiral disc pump is worked for 360° of rotation. This contrasts with most prior art peristaltic pumps which are only able to function throughout, say,

260° of rotation at their most efficient.

It can be seen from Figs. 6 and 8 that the inlet and outlet of the pumping element 55 can be placed side by side in overlapping relation and in the same plane. The combination of the 360° of disc pumping action and side by side layout of the inlet and outlet enables a compact peristaltic pump to be provided and one in which the replacement of the pumping element can be readily facilitated.

Fig. 10 shows the relevant components of a single spiral disc pump 80 having a single spiral pumping disc 81 fitted above a stationary pumping bed 82. In this case the pumping bed 82 and the disc 81 incorporate cutaway sections 84, 85 where the inlet and outlet of pumping element or tube 83 overlap. Those cutaways 84 and 85 on bed 82 and disc 81, respectively, are such that the entry and exit of tube 83 into the pump can be provided with ease. Even though the embodiment shown in Figs 6-9 of the drawings concern a double spiral disc arrangement with both discs being moved via an armature, it will be appreciated that another embodiment comprises a further disc or discs stacked together in similar relation above and/or below the layout shown in Fig 6 with additional armatures 54 and rollers 53 as appropriate. It will also be appreciated that the motion applied to discs 51 could be provided by arrangements similar to those shown in Figs 4 and 5.

While the second aspect of the present invention can be worked in the arrangements depicted in the drawings another embodiment (not shown) provides that a pump of this invention be fitted within a water box. That water box can be provided with a cam which acts against a wall of the box. By appropriate timing of the cam action to move the wall of the box with the contained pump it will be possible to assist the opening of a crushed tube or pumping element 55 or 83 at positions along the tube behind the pumping disc. Such a suction induced restoring force to the pumping element or tube

55, 83 may be employed in place of or in conjunction with fixedly connecting the pumping tube or element to respective adjacent pumping discs or between a pumping disc and fixed pumping bed as shown in the examples in the aforementioned International patent application and in accord with the first aspect of the present invention.

In Fig.9(a) the section shown is at the perimeter of discs 51 in the direction of section IV-IV of Fig. 6 with the inlet and the outlet of the tube 55 in their open position while in Fig. 9(b) the tube 55 at inlet and outlet is undergoing crushing forces from discs 51. The embodiment of Fig. 11 employs a single movable helical disc 90 which operates against an elliptically cross-sectioned tube or pumping membrane 91 positioned on a fixed helical/spiral pumping bed 92 to achieve a peristaltic pumping action.

Inlet and/or outlet 93 project from housing parts 94 with clamping pieces 95 gripping membrane 91 at each end.

Oscillation of disc 90 under the action of rotating armature 96 and tapered rollers 97, where two rollers above disc 90 and one below function to impart oscillation to disc 90.

Fig. 12 is a twin disc version of the embodiment of Fig. 11 which functions in a similar manner to the embodiment of Fig. 6, and wherein like parts are similarly numbered to those of the embodiment of Fig. 11.

In the embodiments of Figs. 11 and 12, the membrane 91 is firmly attached to disc 90 and bed 92 (Fig. 11) or to both discs 90 (Fig. 12). In small scale pumps of these forms, it may be possible to employ a membrane which is unattached while being resilient enough to return to its original shape once the compressive pumping force is removed. Each of the embodiments of Figs. 13-16 employs a positive (pressure closure) and negative (suction opening) hydraulically controlled multi- chambered arrangement which acts by sequentially compressing and restoring the shape of pumping tube 100. Like parts as between Figs. 13 and 14 are similarly numbered as are like parts between Figs. 11 and 13.

As seen from Fig. 15 a helical disc 90 oscillates around multiple chambers 101 with each chamber 101 containing an associated part of membrane 100 and a piston 102. Each piston 102 works on its associated contained volume of hydraulic fluid which fills that chamber. As piston 102 rises and falls, membrane 100 closes and opens as a result of the positive and negative pressure applied by each piston 102 through the hydraulic fluid.

For each of the embodiments of Figs. 13-16 the sequential opening and closing of each membrane section 100 within each chamber 101 is achieved under the action of oscillating disc 90 which are positively connected to each piston 102 as shown, for example, in Figs. 15(a) and (b).

In the embodiments of Figs 13-16 it has been found that 10 to 12 chambers are required to achieve a relatively smooth pumping action. In the embodiment of Fig. 14 ten chambers are shown which are operated upon via an outer planar control ring 103 accommodating two disc working rollers 104 while the underside disc 105 is mounted with a single working roller 104. A swivel bearing 106 mounts disc 90 to the central shaft 107. That operating mechanism being used in place of armature 96 as employed in the embodiment of Fig.13.

In the embodiments of Figs 13-16, separate chambers 101 forming a spiral configuration may contain tubular of elliptical membranes or a common diaphragm. When the chambers 101 are operated upon by the spiral geometry of disc 90 a peristaltic pumping action is applied to the membrane or diaphragm.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A pumping mechanism for providing a peristaltic pumping action of the kind described comprising a flexible fluid transmitting pumping element arranged in a substantially planar at least partially circular path, said pumping element having an inlet at one end and an outlet at its opposite end and being sandwiched between two discs and coupled to the respective discs around curved paths so as to move in sympathy with the relative motion of the discs by moving to reduce the fluid transmitting cross-sectional area of the pumping element as adjacent points on the discs move toward each other and to increase the fluid transmitting cross-sectional area of the pumping element as those adjacent points move away from each other, and wherein motion is imparted to both discs to reduce and increase the spacing between adjacent points on the circumference of the discs such that when a pair of adjacent points are at their closest the diametrally opposed adjacent points of the two discs are maximally separated and further wherein the spacing between the discs progressively varies circumferentially of the discs to impart a peristaltic pumping action to the pumping element.

2. A pumping mechanism as claimed in claim 1 comprising a freely rotatable armature passing through openings in the centres of the discs wherein the armature comprises a set of at least one radially projecting arm in contact with each disc to impart relative motion to the discs.

3. A mechanism as claimed in claim 2 wherein there are at least two diametrally opposed radially projecting arms in contact with each disc.

4. A pumping mechanism as claimed in claim 2 or 3 wherein the armature comprises an eccentric camming surface which is adapted to assist opening of the pumping element during separation of the discs.

5. A pumping mechanism as claimed in claim 1 comprising compressing roller means adapted to act against the respective discs in an opposed manner and wherein the discs are mounted on swivel bearings on a common central axis.

6. A mechanism as claimed in claim 5 comprising further roller means acting on the inner faces of the opposed discs to control separation of the discs.

7. A pumping mechanism for providing a peristaltic pumping action of the kind described comprising a flexible fluid transmitting pumping element arranged in a substantially planar at least partially circular path, said pumping element having an inlet at one end and an outlet at is opposite end and being sandwiched between at least one disc and a pumping bed, said element being coupled to the respective disc and bed around curved paths so as to move in sympathy with the relative motion between the disc and bed by moving to reduce the fluid transmitting cross-sectional area of the pumping element as adjacent points on the disc and bed move toward each other and to increase the fluid transmitting cross-sectional area of the pumping element as those adjacent points move away from each other, and wherein motion is imparted to the disc to reduce and increase the spacing between adjacent points at the circumference of the disc and the bed such that when a pair of adjacent points are at their closest the diametrally opposed adjacent points of the disc and bed are maximally separated such that the spacing between the disc and bed progressively varies circumferentially of the disc and bed, to impart a peristaltic pumping action to the pumping element, and further wherein the disc and bed are shaped as complementary spiral surfaces.

8. A pumping mechanism as claimed in claim 7 wherein the bed is formed as a further disc and the discs are both movable.

9. A pumping mechanism as claimed in claim 7 or 8 wherein the motion of the disc or discs is provided via a rotatable armature having a set of radially projecting arms for each disc wherein the disc motion occurs via contact between respective arms and the or each disc as the armature is rotated.

10. A pumping mechanism as claimed in claim 7 wherein the bed is formed as a plurality of chambers containing hydraulic fluid acted upon via compression means moved under the action of the disc to compress and expand the pumping element.