US2877714A - Variable displacement tubing pump - Google Patents

Description

March 17, 1959 l.. v. soRG ErAL 2,877,714

VARIBLE DISPLACEMENT TUBING run/1P Filed oct. so, 1957 4 sheets-shet 1 March 17, '1959 L. v. soRG Er'AL v y2,877,714

' VARIABLE DISPLGEMENT TUBING P UMP Filed oct. z 0, 1957 f 4 sheets-sneer 4 @aver/:757m

United States Patent VARIABLE DISPLACEMENT TUBING PUMP Leonard V. Sorg, Kansas City, and John C. Lamkin,

Independence, Mo., assignors to Standard Oil Company, Chicago, Ill., a corporation of Indiana Application October 30, 1957, Serial No. 693,316

7 Claims. (Cl. 10S-149) This invention relates to pumps and more particularly to peristaltic pumps adapted to transfer a plurality of streams.

Pumps employing flexible tubes have beenproposed heretofore and in the previously known forms of such pumps, a flexible tube is progressively compressed by a series of fingers. Variations in rates of flow are obtained by providing tubing of different size or by a variable speed motor and gear system which changes the speed of the movement of the fingers. Such means for varying pumping rate are both expensive and inconvenient.

It is, therefore a primary object of our invention to provide a peristaltic pump which is readily adjustable and which is adaptable for a plurality of separate streams. An additional object is to provide a pump which is adapted for continuous duty and wherein the output of such pump can be adjusted without interrupting the operation of the pump. A further object of the invention is to provide a pump of this type which has a long operating life. A more specific object of the invention is to provide a peristaltic pump wherein a plurality of streams is pumped through a plurality of tubes, the flow rate through each of said tubes being independent of each other tube. These and other objects of the invention will appear hereinafter as the description thereof proceeds.

Briefly, our invention comprises an apparatus -for simultaneously pumping several streams in individual tubes with a single constant speed drive. The variability in the pumping rate is obtained by controlling the extent to which the tubing may expand upon the release of the fingers and by the number of fingers involvedinvthe pumping action over a given length of the tubing. The capacity of each tubing is adjusted by a controlled positioning of the contact plate associated with each finger, the contactplate being positioned by appropriate springs and set screws. The number of fingers involved in the pumping action on the other hand can be determined by limiting the number of adjacent backing plates which can cooperate with the pumping fingers.

Further details of construction and advantages of our invention will be described in connection with a preferred embodiment thereof illustrated in the accompanying drawings wherein:

Figure l is a top plan view;

Figures 2 and 3 are front elevations with parts removed to illustrate the drive mechanism;

Figure 4 is a side view of the apparatus in Figures l to 3;

Figure 5 is a `front View with an end plate designed to accommodate six tubes;

Figures 6 and 7 illustrate how the pumping capacity lcan be varied by positioning the recoil plate when using a large pumping tube; and

Figures 8 and 9 schematically illustrate the adjustment of the backing plate to control pumping rate.

For a constant speed drive the flow rate of our pump is dependent only upon the volume of fluid trapped within the tube 10 as the fingers 11A--11L move forward f 2,877,714' Patentedv Mar. 1 7, 1959 progressively. By our invention the volume of trapped liquid can be varied within broad limits in two ways.

The pump operates by moving the series of fingers 11A-IIL against the elastic tube 10 which is held in place by the adjustable plates 12. These plates serve to locate the tube of selected size in proper position with respect to the fingers 11A-IIL. Each plate 12, 12a and 12b is supported by a pair of adjustable threaded rods 13. These rods pass through the casing 14 of the apparatus and have one end pivoted by a ball-type joint 15 to the backing plates 12, 12a and 12b allowing horizontal and vertical tilting of each plate. The springs 16 hold the plates 12, 12a and 12b against the tubes 10.

The fingers 11A-IIL are operated from a cam 17 mounted on a shaft 18 driven by pulley 30 and are pivoted on bearing shaft 19. As the cam shaft 18 is rotated, the associated cams 17 cause the fingers 11A11L to oscillate about the bearing shaft 19. As the fingers 11A-IIL move forward, i. e. toward the backing plates 12, 12a and 12b, they squeeze the rubber tube 10 against the plates 12, 12a or 12b. The forward and backward position and the horizontal and vertical angle of each plate is controlled by tightening or loosening the nuts 20 on the four rods 13 supporting each plate 12, 12a or 12b.

Some control can be obtained by slanting the plates 12, 12a and 12b so that the number of figures involved in the pumping action is reduced. Figure 2 shows the positioning of the plates 12, 12a and 12b for maximum throughput and Figure 3 shows the positioning of the plates 12, 12a and 12b for a lesser throughput.

Figures 6 and 7 show how the `capacity of the pump can be varied with a tube 10 which is large enough to occupy the entire space within which the fingers 11A--11L operate. The volume of the tube embraced by the fingers is dependent upon the extent to which the tube 10 is permitted to resume its original shape when the center fingers 11F and 11G reach the point of most backward travel.

Figure 6 represents a positioning of the tube 10 in which the plates 12, 12aI or 12b are disposed so that When any finger is at its most withdrawn position with respect to a backing plate 12, the tube 10 does not open completely.

Figure 7 represents the setting of the plates 12, 12a and 12b which is used if a maximum fiow through tube 10 is desired. Here it will be noted that the maximum I. D. of the portion of the tube embraced by the fingers is equivalent to the normal I. D. of the tube whereas in Figure 6 the I. D. at 22 is substantially less than the full capacity of the tube 10. Accordingly,` in Figure 7, the volume 23 entrapped between the outer pair of fingers 11A and 11L is the maximum obtainable.

From Figures 6 and 7 it will be apparent that by adjusting the backing plate 12, the capacity of the pump is varied and controlled. This control is possible on each of the plurality of tubes 10 of Figures 2 and 3 and the adjustment is independent of each of the individual tubes 10 in the pump.

Figures 8 and 9 illustrate a system for positioning the tube 10 to obtain variable flow rates wherein the outside diameter of the tube 10 is such that it does not occupy completely the space between the lingers 11 and the volume entrapped in the tube 10 is dependent upon which pair of fingers will act to close the tube at two points thereby trapping the liquid therebetween. In Figure S, representing the maximum flow rate, the backing plate 12 is positioned so that the tube 10 is simultaneously closed by the most remote fingers 11A and 11L in the array. On the other hand, in Figure 9, the section is illustrated wherein something less than the total span of fingers closes space portions of the tube simultaneously to entrap the uid volume 25 being pumped. In Figure 9, the backing plate 12 is slanted by adjusting the rods 13 so that fingers 11A and ,11L close the tube 10. This is accomplished by allowing one side of the plate 12 to travel with the tube 10 as the finger 11 moves.

The plate 12 is anchored on the other side by tightening the corresponding adjusting nut 20 so that the tube 10 will close when a finger 11] has reached its forward position. The nuts adjusting the first side of the plate are loosened so that the spring 16 displaces the plate 12 to the position shown which allows the tube 10 to be closed before the end finger 11L in the array reaches its maximum forward position. forwardly with the tube 10 closed as shown in Figure 9.

Referring to Figure 9, the adjusting rod 13, being provided with the ball-type joint 15 shown in Figures 8 and 9, allows the plate 12 to be slanted at an angle in relation to the rod 13. The plates 12, 12a and 12b are drilled and ground to hold a small spherical bearing 26 which is held in place by a washer 27 to provide a universal joint. The springs 16 override the rods 13. Ball joints are provided at the corners of all backing plates 12, 12a and 12b.

Figure shows an end plate 28 with three tubes 10 although a plurality of six tubes may be operated Within the pump. Erosive action of the end plate 28 upon the ow tube is prevented by providing the grommets 29 in the end plate 28. Removal -of the end plate 28 reveals the apparatus as shown in Figures 2 and 3 havin-g the individually controllable backing plates 12, 12a and 12b. A set of four studs or rods 13 attached by universal joints at the backing plate 12 and the associated springs 16 is the means whereby the distance between the fingers 11 and the backing plates 12, 12a and 12b may be varied. The positions of the backing plates 12, 12a and 12b are adjustable by means of nuts 20 upon the threaded studs or rods 13. Each Iof the three backing plates 12 and 21 is individually and separately variable which permits the control of the separate fiows of the plural streams in the tubes 10.

From the above it will be apparent that we have attained the objects of our invention by providing an apparatus in which the flow in any particular stream can be adjusted during operation of the pump without affecting any Aof the other streams. This can be done Without modifying the drive mechanism and without varying the size of the tube used.

Although we have described our invention with ref ence to preferred embodiments thereof, it should be understood that these are by way of illustration only. Accordingly, other modifications and techniques are contemplated and can be made by those skilled in the art without departing from the spirit and scope of the invention.

What we claim is:

l. Pumping means comprising a housing having a pair of spaced walls, a shaft supported in said housing, an

The end linger 11L then completes its travel l array of pumping fingers journalled on the said shaft to provide a common pivotal axis therefor, each of said fingers extending upwardly between said walls, a bifurcated yoke on the lower ends of said lingers, a second shaft journalled in the said housing, a series of cams fixed to the said second shaft, each cam engaging one of said yokes, individual tube-supporting plates mounted in the housing between said walls, said fingers being successively oscillatable about the first shaft in response to rotation of said cam shaft to swing said fingers towards said tubesupporting plates, resilient means adjustably supporting said plates, and a plurality of fiexible tubes extending through said housing between said array of fingers and said tube-supporting plates, said tube-supporting plates being individually adjustable to vary the pumping rate of each tube independently of each other tube.

2. Pumping means as defined in claim l, the spacing of said plates from said array of fingers being slightly less than the internal diameter of a tube passing through said housing.

3. A peristaltic pump comprising in combination a pump housing, an array of elastic tubes extending through said housing, an array of tube-compressing fingers in said housing, a first shaft to which said fingers are journalled intermediate their ends, a second shaft, parallel to the first, a plurality of cams on said second shaft, said cams engaging cam follower means on the ends of said fingers, whereby rotation of said cams actuates said lingers successively against said tubes, and stop plate means backing said array of elastic tubes, said stop plate means being individually and independently supported in opposition to the action of said ngers whereby the pumping capacity of each tube is independently adjustable by the position of the stop plate means.

4. The pump of claim 3 wherein the stop plate means are adjustable from end to end thereby to control the maximum span of fingers in said array.

5. The pump of claim 3 wherein the capacity of the pump is adjusted by the positioning of the individual stop plate means associated with the corresponding tube so as to limit the full expansion of the tube.

6. The pump of claim 3 wherein said elastic tubes are all of the same internal flow capacity.

7. The pump of claim 3 wherein said housing includes spaced end plates, said end plates being provided with a plurality of pairs of aligned tube-receiving and positioning ports, one pair for each of said elastic tubes.

References Cited in the file of this patent UNITED STATES PATENTS

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