US3427986A - Fluid pump with controlled variable flow - Google Patents

Description

eb. 18, 1969 E. r2. comma.

FLUID PUMP WITH CONTROLLED VARIABLE FLOW l of 3 Sheet Filed June 27, 1957 INVENTOR Per.. 1s, 1969 E. n. CRNEIL 3,427,986

FLUID PUMP WITH CONTROLLED VARIABLE FLOW Filed June 27, 1967 sheet 2 of s I INVENTOR Feb. 18, 1969 E. R. coRNEn.

FLUID PUMP WITH CONTROLLED VARIABLE FLOW med .June 27, 1967 Sheet INVENTOR United States Patent O Claims ABSTRACT OF THE DISCLOSURE Fluid pump in which reciprocating, or oscillating members distort a tube, progressively along a length of the tube to produce a fluid flow. The members are reciprocated about a first centre by a cam or similar action, and constrained by a linkage also to reciprocate about a second centre. By varying the position of the second centre, relative to a line through the .irst centre and a point of attachment of the linkage to a member, the displacement of the member, and the degree of distortion of the tube, between fully closed and fully opened, can be controllably varied and thus the flow rate varied, with constant speed.

BACKGROUND OF TH-E INVENTION Field of the invention The present invention relates to fluid pumps of the type in which a flexible tube is progressively distorted to produce a pumping action and is concerned with providing a volumetric iiow control, independent of speed of operation.

Description of the prior art Various forms of pump have been proposed, in which a iiexible tube is distorted to produce the pumping action. Hitherto, the rate of flow has been controlled by varying the frequency of the cycle and this necessitates variable speed drives. With electric and other constant speed power units, some form of variable speed gear has to be interposed between the pump and the power unit. Also, for very small flows, a small bore tube is required, as the iiow rate is also dependent on the tube bore diameter. To provide a wide range of ilow rates, a variety of tubes with diiering bores, and wall thicknesses, are required. To date, no pumps of the distortable tube type are available to provide a controlled variable flow at a constant Speed from a given iiexible tube member.

SUM-MARY The present invention provides a pump, of the liexible tube type, in which the tube is distorted by reciprocating members, in which the extent of reciprocation of the members is controllably variable. The invention also provides, in a modification thereof, means for adjusting the datum of the reciprocating members, to accommodate tubes of differing wall thicknesses.

BRIEF DESORIPTION OF THE DRAWINGS The invention will be understood by the following description of certain embodiments, by way of example, in conjunction with the accompanying drawings, in which:

FIGURE 1 is an external side view of one for-m of apparatus,

FIGURE 2 is a cross-section, on the line 2 2 of FIG-URE 4, with the mechanism at a minimum flow rate position,

FIG-URE 3 is a cross-section similar to that of FfIG- URE 2, but with the mechanism .at a position approaching that for maximum iiow rate, t

FIGURE 4 is a sectional view on the line 4-4 of FIGURE 2,

FIGURE 5 is a cross-section on the line 5-'5 of FIG- 3,427,986 Patented Feb. 18, 1969 'UfR-E 2, through one oscillating member and associated linkage,

FIGURE 6 is a cross-section on the line 6-6 of FIG- IUfRE 3, but with the oscillating members and associated cams and linkages omitted for clarity, illustrating an additional feature of the invention, and

FIGURE 7 is a plan View illustrating the distortion of al tube.

DESCRIPTION OF TI-I-E PREFERRED EMBODIMENTS Considering FIGURES l to 4, the pump comprises a casing, or housing, 10 open at one side and which is closed by acover plate 11 secured byscrews 12. Acamshaft 13 is journalled at one end 1-4 in anend wall 15 of thehousing 10, and journalled at theother end 16 in thecover plate 11. The cam shaft has a series: ofuniform cams 17 thereon and an extension 18 for driving by some suitable power source, not shown. Thecams 17 are arranged sequentially along thecam shaft 13, normally with equal relative angular displacement.

Mounted on each of thecams 17 is a reciprocating, or oscillating,member 20. Eachmember 20 engages its related cam by ayoke 21 formed at one end of the member. A series ofrotatable supports 22 are journalled in a bearing mounting 23 in onewall 24 of thehousing 10. ASupport 22 is provided for eachmember 20, the mernber slidably retained in aslot 25 in the support.

Thecams 17, on rotation of the cam-shaft 13, cause reciprocation, or oscillation, of themembers 20, each about the axis of rotation of itsrelated support 22. The cams do not directly cause movement of themembers 20 in a direction parallel to their longitudinal axis, although theyokes 21 permit such movement of themembers 20.

Aboss 26 is formed on one side of theyoke 21 on eachmember 20. Thebosses 26 provide pivotal attachment points for one end of links, or levers, 27. The other end of eachlink 27 is pivotally journalled on ashaft 30. Theshaft 30 extends parallel to the axis of rotation of thesupports 22 and also to an axis passing through the points of attachment of thelinks 27 to themembers 20. Theshaft 30 is supported in the housin-g 10 by two parallel, spaced apart, levers in the form of seg-ments 31. The segments are each pivotally mounted at anapex 32 and theshaft 30` is attached at one end o-f thearcuate surface 33 of each segment by screws 3-4. The :arcuate surfaces 33 of the segments are formed to provide arcuate rack lgears which mesh with agear pinion 35 extending across the housing, the gear being rotatably supported inbearings 36 and 37 in theend wall 15 and thecover 11. One end of thegear 35 is extended as ashaft 38 for attachment of acontrol dial 39.

It will be seen that rotation of thegear 35, by thecontrol dial 39, will rotate the segments about their pivotal mountings at theirapices 32. Movement of the segments will vary the position of theshaft 30 relative to the axis of rotation of thesupports 22 and the axis through the pivotal attachment points of thelinks 27 to themembers 20.

In operation, cam-shaft 13 is rotated, rotating thecams 17. Rotation of the cams reciprocates, or oscillates,members 20 about the rotational axis of thesupports 22. Considering themember 20` andlink 27, as shown in EIG- U'RE 2, as themember 20 oscillates about the rotational axis ofsupport 22, thelink 27 also oscillates about the axis ofshaft 30. The relative position of the link and member, in FIGURE 2, is the one `giving substantially minimum ilow. The axis ofshaft 30 is in line with the axis ofsupport 22 and the axis of the point of attachment of thelink 27 with theboss 26. In such a position very little movement of themember 20 along its longitudinal axis occurs.

To produce movement of themembers 20, along their longitudinal axes, thegear 35 is rotated by thedial 39. 'I'his -moves the axis of theshaft 30 out of alignment with the axis of thesupports 22 and the points of attachment of the links to the bosses. One such position ofshaft 30 is shown in FIGURE 3, the shaft approaching the maximum out of line displacement, 1f now the movements of a member andlink 27 is considered, it will be seen that ascamshaft 13 rotates,cam 17 will oscillatemember 20 about the rotational ax-is of thesupport 22.Link 27 will be oscillated aboutshaft 30. However, with shaft displaced out of line with the axis ofsupport 22 and axis of the attachment of thelink 27 withboss 26, two components of movement will be imposed on theboss 26, one normal to a line connecting the rotational axes ofcamshaft 13 and support 22 and the other along that line. Thus themember 20 will be reciprocated along its length. The position ofmember 20 on 180 rotation of the cam 17 -is shown in phantom at 42.

Eachsupport 22 is provided with aflat surface 43 and eachmember 20 is provided with alateral extension 44 at its end remote from theyoke 21. Eachextension 44 has a at surface which faces toward theflat surface 43 on therelated support 22. Reciprocation of amember 20 along its length varies the gap between the opposedflat surfaces 43 and 45.

A flexible tube 50, FIGURES l and 7, is positioned between theflat surfaces 43, 45, and reciprocation of themembers 20 distorts the tube. With thecams 17 equally angularly displaced on the camshaft 13 a regular wave will travel along the tube progressively distorting the tube to provide a pumping action.

With the position ofshaft 30 in FIGURE 2 giving the minimum 4movement of themember 20 along its longitudinal axis, this represents the minimum pum-ping action and minimum flow. The position of theshaft 30 as shown in FIGURE 3 is nearly at the maximum displacement and giving nearly maximum movement ofmember 20 along its longitudinal axis, with corresponding nearly maximum pumping action and flow. Variation of the positioning of theshaft 30, intermediate the two positions shown in FIGURES 2 and 3, will give variation in pumping action and flow. This variation of the position ofshaft 30 is obtained by rotation of thecontrol dial 39. Suitable indents 47, formed in the periphery of thedial 39, and cooperating with a spring-loadedpin 48, or some similar device, provide a convenient way of varying the pumping action, and ow rate by predetermined steps.

Although only the movement of onemember 20 and associatedlink 27 has been described in detail, the movements of allmembers 20 and associatedlinks 27 are the same. To provide reasonable bearing surfaces for themembers 20, each yoke is flanged at 51. Thelinks 27 are positioned between themembers 20, in the spaces provided by theflanges 51. FIGURE 5 illustrates the position of onemember 20` and itslink 27.

Thus, considering FIGURES 1 to 5, it will be seen that rotation of thecamshaft 13 will cause a travelling wave to move along the tube 50, progressively distorting it and then allowing it to return to its undistorted shape. By manipulation of thecontrol dial 39, the amplitude of the wave can be controllably varied from substantially zero to a maximum. At the zero condition the tube is distorted into a closed condition and remains so distorted. Movement of the control dial 39 a small amount will result in `some small amount of reciprocation ofmembers 20, the tube being completely occluded at one spot only at any given point of rotation, the rest of the tube being slightly open. At the maximum condition, the tube will be completely occluded at the one position, which can be considered as the trough of the wave, and will be increasingly opened up to a position which can `be considered as corresponding to the peak of the wave, giving maximum flow. Normally, in the maximum condition, the tube will be completely open, i.e., undistorted at the 4- position considered as the peak of the wave However, this is not a necessity, and there may always be some distortion of the tube 50'. No variation in speed of rotation of thecamshaft 13 is required for this Variation in flow.

It is desirable that some adjustment be available to permit initial adjustment of the gap -between the opposedflat surfaces 43 and 45. The thickness of the wall of tube 50 is likely to vary from tube to tube. It is necessary to completely occlude the tube for maximum pumping activity but at the same time it is desirable to avoid overcompressing the tube to avoid damage.

An additional, optional, feature of the apparatus is the provision of means for adjusting the gap betweensurfaces 43 and 45, independently of thecams 17,members 20 and links 27. As stated above, thesegments 31 are pivotally mounted at theirapices 32. As seen more clearly in FIGURE 6, thesegments 31 are pivotally mounted byrivets 55 on anadjustable yoke member 56. The yoke member is pivotally mounted, at the ends oflegs 57, at the position at which thegear 35 is supported in theend wall 15 and theend cover 11. Conveniently, the ends of thelegs 57 form thebearings 36 and 37 which support thegear 35. By this arrangement, theyoke member 56 can rotationally oscillate about the axis throughbearings 36 and 37. This also means that the position of attachment of thesegments 31 to theyoke member 56 can also rotationally oscillate about the axis throughbearings 36 and 37.

Movement of the yoke will alter the angular position of the segments relative to themembers 20 and links 27. Further, as the segments are also pivotally connected to theshaft 30, to which all thelinks 27 are pivotally connected, the geometry of the relationship betweenmembers 20,links 27,segments 31 andgear 35 will vary with alterat-ion of the angular relationship of the segments.

From a mid-position, theyoke member 56 can be rotated clockwise or anticlockwise. Movement of theyoke member 56 is obtained by acontrol screw 58 rotatably secured in aboss 59 formed on thehousing 10 by ascrew 60. The control screw has a threaded portion 61 at its inner end which engages with a threaded hole in theyoke member 56. The arrangement is seen clearly in FIGURE 2, theyoke member 56 being at one extreme position of adjustment.

If thecontrol screw 58 is rotated to cause the threaded portion 61 to moveyoke 56 anticlockwise as seen in FIGURE 2, then thesegments 31 will also be rotated anticlockwise about an axis through thebearings 36 and 37, and through thegear 35. This movement of the segments will moveshaft 30 anticlockwise about the axis throughbearings 36 and 37. This movement of theshaft 30 will cause thelinks 27 to move slightly to the right, as seen in FIGURE 2, and will also cause themembers 20 to slide slightly to the right, increasing the distance betweensurfaces 43 and 45. Thus thecontrol screw 58 will enable thedatum gap betweenfsurfaces 43 and 45 to be varied. This variation is made without any substantial variation in the operational strokes of themembers 20, which is governed by thegear 35 and thesegments 31.

From the above it will be seen that the invention provides for a variable flow rate, independent of Speed. Also, if desired, adjustment can readily be provided to adapt for differing thickness of tube wall and similar variations.

I claim:

1. A pump for fluids, comprising; a housing; a series of members mounted in said housing for reciprocal and oscillatory rotative movement in a series of parallel planes; support means supporting said members towards one end for reciprocation and for oscillatory rotation about a rst axis, normal to said planes; a first surface on each of the members, extending transverse to said plane; a series of second surfaces, one opposed to each said first surfaces to cooperate therewith; means adjacent the other ends of said members for sequentially oscillating said members about said rst axis; a series of links extending parallel to said planes, a link to each member; each link pivotally attached at one end to a related member adjacent said other end of said member, said links pivotable relative to the members about a second axis parallel to said first axis; means pivotally connecting the links at their rother ends for pivoting movement about a third axis, positioned between said first and second axes and parallel thereto; and means for varying the position of said third axis relative to a plane parallel to and passing through said rst and second axes and thus varying the pivotal position of said other ends of said links; whereby oscillation of said other ends of said members pivots said links about said third axis to impart a reciprocal movement to said members, the extent of said reciprocal movement increasing with increase in displacement of said third axis; reciprocation of said members varying the distance between said iirst and second surfaces for distortion of a exible tube positioned therebetween to produce a pumping action.

2. Apparatus as claimed in claim 1 wherein the means pivotally connecting the links at their other ends comprises a shaft, the longitudinal axis of the shaft comprising said third axis.

3. Apparatus as claimed in claim 2, wherein said means for varying the position of said third axis comprises at least one lever, said shaft mounted at one end of the lever, the other end of said lever pivotally mounted in said housing for rotative movement in a plane parallel to the planes of movement of said members, and means for moving said lever about said axis.

4. Apparatus as claimed in claim 2, said means for varying the position of said third axis comprising; a pair of segmental levers pivotally mounted at their apices in said housing, movable in planes parallel to said planes of movement of said members, said shaft mounted at an end of the segmental levers remote from said apices, a peripheral arcuate surface at said end of each segmental lever; an arcuate rack ygear formed on each of said arcuate surfaces; a pinion gear pivotally mounted in said housing, having an axis of rotation normal to the planes of movement of said segmental levers, said gear meshing with said arcuate rack gears; and means for controllably rotating said gear.

5. Apparatus as claimed in claim 1, wherein the support means supporting said members comprises a series of support members rotatably mounted in a wall of said housing, a support member for each of said members, said second surfaces comprising surfaces on said support members, one surface on each support member.

6. Apparatus as claimed in claim 1,. wherein said means for sequentially oscillating said members comprises; a cam shaft; and a series of cams on said shaft, sequentially angularly displaced, a cam for each said member.

7. Apparatus as claimed inclaim 4, wherein the means for controllably rotating said gear comprises a control dial, rotatable to any one of a series of predetermined positions, and a spring loaded pin adapted for engagement with said dial.

8. Apparatus as claimed inclaim 4, wherein said segmental levers are pivotally mounted at their apices in an adjustable member, said adjustable member supported in said housing for pivotal movement about the axis of rotation of said pinion gear, and including means for pivoting said segmental levers about the axis of said pinion gear, whereby the position of the pivotal axis of said segmental levers and the datum position of the third axis relative to the first and second axes can be varied.

9. Apparatus as claimed in claim 8 wherein said adjustable member comprises a yoke member having parallel spaced apart legs, said yoke memberl including bearings at the ends of the legs for pivotal mounting of the yoke member in said housing, said bearings also providing the pivotal mounting for said pinion gear.

10. Apparatus as claimed in claim 9 wherein the means for pivoting said segmental levers comprises a control screw retained in said housing, said screw including a threaded portion engaging in a cooperating threaded hole in said yoke member.

References Cited UNITED STATES PATENTS 1,922,196 8/1933 Butler 103-148 2,105,200 1/1938 Phelps 103-149 2,877,714 3/1959 Sorg etal 103--149 2,922,379 1/1960 Schultz 103-148 3,083,647 4/1963 Muller 103-148 3,128,716 4/1964 Stallman et al 103--149 DONLEY' I. STOCKING, Primary Examiner. WILBUR J. GOODLIN, Assistant Examiner.

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