US2899905A - becher - Google Patents

Description

Aug. 18, 1959 J. J. BEcHl-:R 2,899,905

' ROLLER PUMP Filed Sept. l1; 1956 2 Sheets-Sheet 1 Aug. 1s, 1959 J. J. BECHER ROLLER PUMP Filed Sept. 1l, 1956 2 sheets-sheet 2 I 2 72 Uefa 2?@71 2,899,905 Patented Aug. 18, 1959 United States tent Office RoLLER PUMP James J. Becher, Chicago,`lll., assigno', by direct and mesne assignments, to Roll-Flex Industries, Ine., a corporation of Illinois Application September 11, 19'56, Serial No. 609,119 110 Claims. (ci. 10s-149) This application is` a continuation-impart of my prior application Serial No. 504,197, filed April 27, 1955; the disclosure of which, to the extent that it is not inconsistent herewith, is specifically incorporated by reference, and relates to improvements in a sanitary leak-proof pump of the type in which the material being pumped is progressively forced through a system of collapsible tubing.

The pump of the invention is of the general class4 characterized by a cylindrical pump casing that supports a rotatable drive shaft in operable engagement with one or more planetary rollers that progressively compress a loop of collapsible tubing disposed in the region of the outer cylindrical wall of the casing. Thus the rollers force the material to be pumped forwardly through the tubing and set up a suction effect in their wake.

In the past, pumps of this general character have had relatively short effective lifetimes. Not only has there been an abnormally pronounced tendency for the parts to wear to the point where they require replacement, but even very short periods of use have seen significant decreases in the pump capacity due to the tendency of the collapsible tubing to take a set from the continuous compression to which it is subjected.

It is the principal object of the present invention to provide a roller pump; that has a minimum of wear; that uniformly distributes such wear as does occur;` that maintains its original capacity substantially unimpaired throughout its useful life; that presentsv a uniform load characteristic to its driving motor; that is efficient in operation and economical to manufacture; and that provides a readily disengageable coupling and uncoupling arrangement for a motor drive shaft.

Briefly, the present invention contemplates a roller pumpthat includes an annular sleeve of resilient deformable material` for transmitting compressive forces from the planetary roller tothe collapsible tubing and this sleeve not only minimizes tubing wear due to its cushioning` effect but it also distributes such wear uniformly. As a further feature the invention utilizes a compression force that acts laterally upon the annular loop' of collapsible tubingand performs a desirable shaping vaction to maintain the cross section of the tubing substantially circular throughout` its useful life andl thereby preserve the original effective' capacity of the pump. Av further improvement in capacity as' well as a further increase in the useful life ofthe pump'is effected'by adding ar suitable lubricant tothe pumping chamber.

The pump ofthe invention is self priming: and'this fact makes it admirablyv adapted for use as a` fuel pump since it is not'- subject to vapor lock.

Other objects and` advantages of the invention will' be# come apparent .duringfthe-cours'e ofthefollowing description.

In' the accompanying drawings forming' a part of`this specification and in'- which likenumerals are to designate like parts throughout the same;-

employed n Fig. 1 is a perspective view of the improved roller pump of the invention with ythe casing members dismantled; y

Fig. 2' is a front sectional View taken in the vertical 'plane of lthe pumping chamber;

Fig. 3 is a plan sectional view taken on the line 3 3 of Fig. 2; l v

Fig. 4 is a front sectional View corresponding generally to Fig. 2 and illustrating a -modified roller arrangement;

Fifg. 5 is an enlarged plan view of the roller arrange# nient of Fig. 4; A

Fig; 6 is an elevational view illustrating the pump of the invention coupled to a driving motor through a novel coupling arrangement; and t v Fig. 7 is a sectional view of the coupling arrangement; Referring now to Figs. l, 2, and 3 :of the drawings, it may be seen that the pump includes a `divided casing consisting of a pump body 11 and an end cover 12 that seals the open end of the pump body and defines therewith a cylindrical pumping chamber 13. p y

The pump body is of a generally hollow cylindrical shape and includes an integral side wall 14 that carries an integral,` openended, cylindrical tubular extension 15 coaxial with the pumping chamber to receive a rotatable drive shaft 16. The end cover is generally circular and includes an annular outer wall 17, adapted for abutting engagement with the exposed annularsurface`18 ofthe pump body, and an inner circular wall 19 with the two walls being connected by a tubular stub 20 that also receives the drive shaft. i I

The parts of the pump casing are secured together by a plurality of screws 21 and for this purpose arev each provided with a plurality of tapped securing lugs 22 suitably spaced about their periphery. y

The pump body is also provided with an integral boss 2.3` formed with a forked passageway having an inner passage 24 extending between the pumping chamber 13 arid the pair of diverging outer passages 25. y

an intermediate portion the drive shaft is formed with aseries of serrations 27 that extend parallel to the axis of the drive-shaft and annular shoulders 28 are pressed onto the shaft and positioned at opposite ends of this serrated portion. The shoulders 2S are spaced apart slightly less than the width of the pumping lchamber' and they serve to center the shaft with respect to the pumping chamber. The shaft is journaled in the tubular extensions 15 and 20 with its serrated portion in frictional driving contact with a planetary roller element 29.

A collapsible tube 30 adapted to conduct the material beingv pumped is disposed within the pumping chamber and formed into a single loop that completely surrounds the'drive shaft. The loop is arranged in contact with the outer circumferential wall provided by the pump body and this wall is preferably provided with a smooth finish to minimize wear on the tube. It will be noted that the tube liesin a single plane inthe pumping chamber and its ends are" brought together in abutting relationship, as indicated at 31, and then are brought through the common passage I 24. Thusat no point do the ends of the tube overlap and thisl arrangement offers a` uniform load to the driving mofor. The ends of the tubing 30 are preferably connected tonyl'on tube fittings 32 suitably mounted in the diverging outer passage 25 but if desired the tubing itself may be b'roiig'ht directly through these passages.

An important new feature of the presentl invention r`e`sides`in the provision'of a resilient flexible endless sleeve 33 that is telescoped between the loop of tubing 30 and the'roller-dn've shaft arrangement for reducing the wear oritlie tubing and for improving the overall performance of tliepump. l'n the embodiment of Figs. l`-' 3, asingle roller 29 of cylindrical fomihaving a length slightly less" than the spacing between the shoulders 28 is employed with the roller being disposed in the generally annular space between the drive shaft 16 and the sleeve 33. The roller is preferably of a plastic material such as nylon and is assembled into the prunpfor frictional surface contact with the serrated portion 27 of the drive shaft. The roller may originally be smooth surfaced as preliminary operation of the pump soon causes the shaft to knurl the roller and create an effective driving engagement therebetween.

The tubing is collapsible and as the drive shaft rotates to move the planetary roller along an annular path and progressively knead or compress the tubing, the material being pumped is forced through the tubing forwardly of the roller and a suction effect is set up in its wake to draw additional material into the tube. The output of the pump is best characterized by the term peristaltic as the pump develops a pumping action that closely follows that of a human heart and even more closely simulates the systems of lower forms of animal life.

The collapsible tubing may be of any suitable resilient and flexible material that is readily compressed and that tends' to restore itself to its original configuration. For

result that the sidewalls of the pumping chamber exert a slight compressive action on the sleeve and limit its tendency to rotate relative to the pump casing and hence to the loop of collapsible tubing. Not only does the sleeve increase the life of the tubing by eliminating direct contact with the knurled roller, but, due to its inherent resiliency, it also tends to cushion the effect of the kneading action of the roller.

Of further importance to the present pump arrangement, is the fact that the sleeve permits the use of a single roller without such use creating any possibility of slipping of the roller as it passes underneath the abutting ends of the looped tubing indicated at 31. This abutting arrangement of the tubing offers the advantage of progeneral use, a vinyl tubing is preferred for its high degree of flexibility. For high temperature applications, a silicone tubing has proven most effective while neoprene is preferred when the material to be pumped is a hydrocarbon. One of the inherent advantages of the pump of the invention is its sanitary construction and in hospital applications or in food handling operations where this feature is of prime importance gum rubber tubing is preferred. Irrespective of which of the above materials or any similar synthetic resilient compounds which are employed 'for the collapsible tubing, one may also form the tubing with suitable cloth or nylon braid and this reinforced construction allows the pump to handle higher pressures and offers increased resistance to wear.

While the materials employed for the collapsible tubing are generally characterized as resilient and cause this tubing to tend to automatically return to its original circular cross sectional shape after the roller has passed by, the tubing has nevertheless exhibited a tendency ultimately to take on a permanent set in a semi-depressed condition and this results in a decrease in the effective capacity of the pump. The potential decrease in capacity is avoided according to the present invention by employing a compression spring 35 that performs a desirable reshaping function on the tubing. The spring is annular andis of approximately .the same diameter as the loop of collapsible tubing so that the spring engages flush against the tubing. Preferably the side wall of the pump body is formed with an annular groove 36 that constitutes a seat for the compression spring and fixes it in place within the pumping chamber.

The spring portion in contact with the collapsible tubing must be smooth surfaced to avoid damaging the tubing 30, and while this smooth surface may be provided in many ways, it is preferably formed by coating the free end of the spring with a suitable plastic.

As shown in Fig. 3, as the nylon roller 29 compresses the collapsible tubing, the walls of the tubing are displaced laterally to shorten the compression spring at this point. However, 180 degrees from this point the compression spring becomes fully extended and acts upon the collapsible tubing to restore it to its original circular cross section. The re-shaping spring, in maintaining the original shape of the spring, offers the advantage that pump operation is uniform for both directions of rotation of the drive shaft and, in addition, the relation between the pump response and the speed of the drive shaft is maintained substantially linear.

The sleeve or tube guard 33 may be of any suitable flexible and resilient material such as a vinyl compound and this sleeve is fabricated to have a width that is slightly greater than the width of the pumping chamber with the viding substantially constant resistance to the roller throughout its path of movement but there is nevertheless `a tendency for the roller to slip as it passes this point. The presence of the sleeve, however, entirely overcomes this tendency. The sleeve diameter is such that the entire periphery of the sleeve is in substantially continuous contact with the collapsible tubing while the radial thick-v ness of the sleeve provides effective driving engagement between the drive shaft and planetary roller without, however,'locking the parts together.

The pump body and end cover `are preferably of aluminum and their extensions carry oil impregnated bronze bushings 38 that cooperate with the drive shaft to provide extremely quiet operation. Preferably the abutting faces of ythe pump body and end cover are provided `with smooth finished surfaces which when brought together form a tightly sealed pumping chamber which has become important in view of the fact that it has proven desirableto utilize a silicone grease or similar material for lubricating the parts in the pumping chamber. vThe presence of the silicone grease greatly increases the life of the collapsible tubing and actually augments the capacity of the pump, presumably because the grease causes a certain expansion of the pumping parts which permits them to develop greater compression. In addition, the

-silicone grease allows the tube guard 33 to rotate very desirable since it distributes the wear to which the tubel guard and the collapsible tubing are subjected and in a large measure is responsible for the long effective life of the present pump. As mentioned previously, the side walls of the pumping chamber exert a slight compression on the tube guard and desirably limit its counter rotation.

With a single roller, as shown in Figs. 1 to 3, the pump tends to momentarily lose its compression each time the roller passes underneath the abutting ends of the tubing and while this is of no consequence in most applications, there are applications where it is important to maintainA continuous compression. In such instances the modified embodiment of Figs. 4 and 5 may be employed. This embodiment is identical with the arrangement of Fig. 3 with the exception that a double roller assembly, designated generally at 40 (see Fig. 5), is substituted for the single planetary roller. The double roller assembly includes a pair of cylini drical rollers 41 which may be of nylon. The rollers are connected by a pair of links 42 of the general type` commonly employed on bicycle chains and the opposite ends of the links are suitably snapped lover headed pins 43 disposed in suitable bores in each of the rollers with the roller beingrotatable relative to the pins. Again the rollers are preferably smooth surfaced at the time of Vinitial assembly kand after a minimum amount of preliminary operation, the knurled portion 27 of the drive shaft develops a corresponding knurl on the rollers to establish a positive driving relationship therebetween. The operation of the embodiment of Fig. 4 is generally similar to that of the preferred embodiment with the sonorit :exception that the collapsible tubing is maintained compressed at at least one point at all times.

A further feature of the pump construction of the present invention relates to the manner for coupling and uncoupling it With the motor drive shaft. This structure is brought out in Figs. 6 and 7 wherein a driving motor of any suitable type is designated generally as 50 and includes a driving shaft 51 adapted for connection to the pump drive shaft 16. As shown, the pump shaft vis formed with a radial bore 52 that receives the motor drive shaft 51 in telescoping relationship. Preferably, one area of the circumference of the motor shaft is flattened, as indicated at 53, for engagement with a setscrew 54 that is carried ina tapped radial bore 55 formed in a coupling collar 56 telescoped over the overlapping portions of the shafts 16 and 51. The setscrew projects through a radial bore 57 in the pump shaft 16 to engage the attened area S3 of the motor shaft and effect a firm driving engagement between the two shafts. It should be apparent that the coupling and uncoupling operation is highly simplified by this arrangement, it being necessary merely to back off the setscrew 54 and withdraw the shafts axially. The simplicity of this arrangement has attracted considerable attention in the trade.

Preferably, the pump is mounted directly on the motor framework 'and for this purpose the base 60 of the pump is bolted to a suitable supporting and locking plate or arm 61 which projects into a suitable opening in a bracket 62 that extends upwardly from the motors supporting framework 63. The ann 61 abuts against the bracket 62 and holds the pump casing stationary while the shaft is rotated. Preferably the arm 61 is provided with a resilient sleeve 64 at its free end and this sleeve cushions the interactions between the motor bracket 62 and the pump arm 61. As a result the pumpbody is connected to the motor entirely through resiliently connected members.

It should be understood that the description of the preferred form of the invention is for the purpose of complying with section 112, title 35 of the U.S. Code and that the appended claims should be construed as broadly as the prior art will permit.

I claim:

l. In a pump, casing means including spaced side walls and an outer circumferential wall extending therebetween and defining a cylindrical pumping chamber, a rotatable drive shaft mo-unted in said casing means in coaxial relationship with said chamber, collapsible tubing in said casing means surrounding said shaft and having its ends extending through said casing means, resilient means in said chamber reacting between said tubing and one of said side walls to urge said tubing against the other side wall, and compression means disposed between said shaft and said tubing in driving engagement with said shaft and movable along an annular path in response to rotation of said shaft to compress successive portio-ns of said tubing against said outer circumferential Wall.

2. In a pump, casing means including spaced side walls and an outer circumferential wall extending therebetween and defining a cylindrical pumping chamber, a rotatable drive shaft mounted in said casing means in coaxial relationship with said chamber, collapsible tubing in said casing means surrounding said shaft and having its ends extending through said casing means, resilient means in said chamber reacting between said tubing and one o-f said side walls to urge said tubing against the other side wall, and roller means disposed between said shaft and said tubing in driving engagement with said shaft and movable along an annular path in response to rotation of said shaft, said roller being of such radial dimension as to compress successive portions of said tubing against said outer circumferential wall.

3. In a pump, casing means including spaced side walls and an outer circumferential 'wall extending therebetween and defining a cylindrical pumping chamber, a rotatable drive shaft mounted in said casing means in coaxial relationship with said chamber, collapsible tubing in said casing means surounding said shaft and having its ends extending through said casing means, annular spring means in said chamber seated in an annular groove in one of said side walls to urge said tubing against the other side wall, and compression means disposed between said shaft and said tubing in driving engagement with said shaft and movable along an annular path in response to rotation of said shaft to compress successive portions of said tubing against said outer circumferential lwall.

4. In a pump, casing means including spaced side Walls and an outer circumferential lwall extending therebetween to define a cylindrical pumping chamber, a rotatable drive shaft mounted in said casing means in coaxial relationship with said chamber, collapsible tubing in said casing means surrounding said shaft and having its ends extending through said casing means, a continuous sleeve positioned between said shaft and said tubing, resilient means in said chamber compressing said tub-ing in a direction generally parallel to the lengthwise direction of the shaft, and compression means in driving engagement with said shaft and disposed between said shaft and said sleeve in abutting engagement with said sleeve and movable along an annular path in response to rotation of said shaft to urge the engaged portion of Said sleeve outwardly and compress successive portions of said tubing against said wall.

5. In a pump, casing means including spaced side Walls and an outer circumferential wall extending therebetween to define a cylindrical pumping chamber, a rotatable drive shaft mounted in said casing means in coaxial relationship with said chamber, collapsible tubing in said casing means surounding said shaft and having its ends extending through said casing means, a continuous sleeve positioned between said shaft and said tubing, annular spring means in said chamber compressing said tub-ing in a direction generally parallel to the lengthwise direction of the shaft, and roller means disposed between said shaft and said sleeve in driving engagement with said shaft, said roller means being of such radial dimension as to force said sleeve outwardly in the region of contact therewith and compress said tubing against the outer circumferential wall of said casing such that rotation of said shaft drives said roller means along an annular path and momentarily compresses successive portions of said tubing.

6. In a pump, casing means including spaced side walls and an outer circumferential wall extending therebetween to define a cylindrical pumping chamber, a rotatable drive shaft mounted -in said casing means in coaxial relationship with said chamber, collapsible tubing in said casing means surrounding said shaft and having its ends extending through said casing means, a continuous sleeve of resilient deformable material positioned between said shaft and said tubing, annular spring means in said chamber compressing said tubing in a direction generally parallel to the lengthwise direction of the shaft, and roller means disposed between said shaft and said sleeve in driving engagement with said shaft, said roller means being of such radial dimension as to force said sleeve outwardly in the region of contact therewith and cornpress lsaid tubing against the outer circumferential wall of said casing such that rotation of said shaft drives said roller means along an annular path and momentarily compresses successive portions of said tubing.

7. In a pump, casing means including spaced side walls and an outer circumferential wall extending therebetween to define a cylindrical pump chamber, a rotatable drive shaft mounted in said casing means in coaxial relationship with said chamber, collapsible tubing in said casing means surrounding said shaft and having its ends extending through said casing means, a continuous sleeve positioned between said shaft and said tubing, annular spring means in said chamber seated in an annular groove `in one of said side walls to urge said tubing against the other side wall, and roller means disposed between said shaft and said sleeve in driving engagement with said shaft, said roller means being of such radial dimension as to force said sleeve outwardly in the region of Contact therewith and compress said tubing against said outer circumferential wall of said casing such that rotation of said shaft drives said roller means along an annular path and momentarily compresses successive portions of said tubing.

8. In a pump, a pair of casing members rigidly secured together and providing spaced side walls and an outer circumferential wall extending therebetween and defining a cylindrical pumping chamber, said members having oppositely projecting aligned tubular extensions concentric with said chamber to provide bearing sleeves, a rotatable drive shaft journaled in said sleeves with one of said tubular extensions having an open outer end accommodating said drive shaft and the other tubular extension having a closed outer end substantially isolating the pumping chamber, collapsible tubing in said chamber surrounding said shaft and having its ends extending through said circumferential wall, resilient means in said chamber reacting between said tubing and one of said side walls to urge said tubing against the other side wall, and roller means disposed between said shaft and said tubing in driving engagement with said shaft and being movable along an annular path in response to rotation of said shaft, said roller being of such radial dimension as to compress successive portions of said tubing against said outer circumferential wall.

9. In a pump, casing means including an outer circumferential wall defining a cylindrical pumping cham ber, a rotatable drive shaft journaled in said casing means in coaxial relationship with said chamber, a length of ,collapsible tubing formed into a single loop surrounding said shaft in said pumping chamber and arranged in a common plane substantially normal to the axis of said shaft, the end portions of said loop within said chamber extending radially outwardly in abutting relationship through a common passage in the outer circumferential wall of said casing means, a continuous sleeve positioned between said shaft and said tubing, and roller means disposed between said shaft and said sleeve in driving engagement with said shaft, said roller means comprising a pair of cylindrical rollers, and a yoke connecting said rollers in spaced parallel relationship, with the radial dimension, of the rollers being sufficient to force said sleeve outwardly in the region of contact therewith and compress said tubing against the outer circumferential Wall such that rotation of said shaft drives said rollers along an annular path and each roller momentarily compresses successive portions of said tubing, and with the spacing of said rollers being sufficient to bridge the point at which said collapsible tubing is in abutting engagement.

10. In a pump, casing means including Van outer circumferential wall defining a cylindrical pumping chamber, a rotatable drive shaft journaled in said casing means in coaxial relationship with said chamber, a length of collapsible tubing formed into a single loop surrounding said shaft in said pumping chamber and arranged in a common plane substantially normal to the axis of said shaft, the end portions of said loop within said chamber extending radially outwardly in abutting relationship through a common passage in the o'uter circumferential wall of said casing means, and roller means disposed between said shaft and said tubing in driving engagement with said shaft, said roller means including a pair of cylindrical rollers, and a yoke connecting said rollers in spaced parallel relationship, with the radial dimension of the rollers being sufficient to force said tubing outwardly at the regions thereof adjacent the rollers and compress said tubing against the outer circumferential wall such that rotation of said shaft drives said rollers along an annular path and each roller momentarily compresses successive portions of said tubing, and with the spacing of said rollers being sufficient to bridge the point at which said collapsible tubing is in abutting engagement.

References Cited in the file of this patent UNITED STATES PATENTS France May 19, 1875

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