US2551605A - Displacement pump - Google Patents

Description

May 8, 1951 D. T. JAMES ET AL 2,551,605

DISPLACEMENT PUMP Filed Dec. 3l, 1948 3 Sheets-Sheet l /m/fA/raes May 11951 D. T. JAMES ET AL 2,551,605

DISPLACEMENT PUMP Filed Dec. .'51, 1948 3 Sheets-Sheet 2 May 8 1951 D. T. JAMES ET Al. 2,5514605 DISPLACEMENT PUMP Filed DSC. 31, 1948 3 SheetS-Slleel'I 3 Patented May 8, 1951 DISPLACEMENT PUMP David T. James, Middletown, and Arthur J. Rawson, Rocky Springs, Md.

Application December 31, 1948, Serial No. `68,708

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 5 Claims.

This invention relates to pumps, particularly t an improved positive displacement pump in which an eccentric member compresses :an elastic tube to expel the contents of the tube.

The invention described herein may be manufactured and used by or for the Government, for governmental purposes, without the payment to us of any royalty thereon.

Prior pumps of this type had several disadvantages. The compressing member set up severe strains and distortions in the tube member. Disintegration of the tube was hastened by frictional or abrasive action, with resultant excessive maintenance and replacement costs.

The primary object of the present invention is to improve the construction, assembly, and operation of a pump oi the type described herein. Another object is to provide such a pump in which standard rubber tubing can be employed. A further object is to provide such a pump that is capable of delivering an exact measured quantity of fluid, as required by the automatic inoculating apparatus described in the co-pending application of John C. Wagner and David T. James, led December 16, 1948, Serial Number 65,542.

Other equally important objects will more plainly appear from the detailed specication and drawings herein presented in exemplication but not in limitation of the present invention. Like reference characters represent like parts of a preferred embodiment of the present invention, shown in the accompanying drawings which illustrate diagrammatically in:

Figure l; an isometric view of the assembled pump mechanism with portions shown broken away, for clarity.

Figure 2; an isometric View of the pump core showing the tube arrangement and the inlet and outlet path for the iluid.

Figure 3; a vertical longitudinal cross-sectional view taken on the plane 2, 2, 2, 2 of Figure l.

Figure 4; a vertical transverse cross-sectional view taken on the plane 3, 3, 3, 3 of Figure 1.

As shown in Figure 2, elastic tubing 22 leads from container 2l and enters core 23 through inlet aperture 36, then out of slot 2 and around core 23 for more than one turn, and then into slot 25 and out of outlet aperture 26.

As shown in Figure 3, lcore 23 is joined to iixed shaft I by suitable attaching means such as bolt or screw 28.

As shown in Figure 4, outer ring I2 is rotated on shaft I5 by means of driving pinion 3| and driven gear 32 which is fixed to ring I2.

External ring or driven shell I2 contains an eccentric pocket 3i). Internal ring II is adjustably mounted in pocket 30. Internal ring II' contains an eccentric pocket 40. Roller bearing I9 is mounted in pocket 40, and compressor ring 29 is mounted for free rotation in iloating concentric contact with the internal circumference of bearing I0, and free floating eccentric contact with the outwardly disposed external wall of tube 22, and is arranged to progressively collapse tube 22 inwardly against core 23, when in Vopera.- tion, as shown in Figures l and 3.

The iamount of eccentricity aiorded by pocket 40 is controlled by the rotational adjustment of ring II in pocket 3D. This adjustment is made by first loosening screw I4 and thus releasing lock nut i3. This permits the relative adjustment to be made by turning ring I I by hand. Thereafter ring lI is clamped into its new adjusted position by tightening screw I4 and thus pulling lock nut I3 back into its locking position in its housing formed by groove I6 in ring I I, and by groove I1 in ring I2, as shown in Figures 3 and 4.

This permits adjustment to suit varying thicknesses of tubing. It also permits adjustment to a concentric position so that the assembly of core 23 and tubing 22 in the pump 20 can thereby be greatly facilitated.

Within the limits of the range from concentricity to maximum eccentricity, it is apparent that an infinite number of adjustments may be made. This affords accurate adjustment for tubes of various internal diameters and thereby provides means for accurately metering the amount of fluid delivered by one or more, or by fractional, revolutions of pump 20. This arrangement is particularly valuable when used in conjunction with the revolution controlV mechanism described in co-pending application of David T. James, filed December 31, 1948, Serial Number 68,707, which matured into Patent N0. 2,537,673 dated January 9, 1951.

In operation, power may be applied to drive pinion 3|. This rotates driven gear 32, and external ring I2, around fixed shaft I5, and core 23 which is joined to shaft I5.

Internal ring I'I is locked to external ring I2 as explained herein, and rotates with roller bearing I0, ring I2 and gear 32, around core 23, in the direction shown by the arrows in Figure 1. As ring 29 is free to rotate within roller bearing I0, it applies practically frictionless pressure inwardly on tube 22, as there is no relative sliding or slipping movement between tube 22 and ring 29. Any tendency to slide or slip is overcome by the action of roller bearing I0 on ring 29. It is im-l portant to note at this point that the inward pressure of ring 29 on tube 22 compresses tube 22, which also reduces internal friction and wear on tube 22, as compared to prior pumps that apply outward pressure which acts to stretch the tubing and thereby increases the rate of wear thereon.

From the foregoing it becomes apparent that standard rubber or other elastic tubing may be employed, because the stationary core 23 holds the tubing in place without anchoring along one or more elements of the tubing, as shown in prior U. S. Patent No. 2,414,355, to Boris Bogoslowsky, issued January 14, 1947. Anchoring of Vam'pt'ype will inescapably cause longitudinal shear which critically increases wear.

The present invention permits normal collapsing only, which also removes another cause of wear in prior pumps.

It is also apparent that core 23 may readily be removed from, or inserted in, pump 2) by means of the attaching bolt or screw 28. This permits rapid changing of tubing 22 to tubing of a different Iinternal diameter when it is desired to change the capacity of pump 2D. With a Vpredetermined internal diameter of tube 22 and a predetermined effective length of tube 22, the volume of uid delivered per revolution of pump 2l!- is easily determined.

With the direction of rotation as indicated by the arrows in Figures 2 and 4, iiuid may be pumped from container 2| through tube 22 at inlet aperture 36 and at outlet aperture 26 where the fluid is ejected at the delivery end 21 of tube 22, as shown in Figure 1. A reversal of rotation reverses the direction of flow just described.

While a preferred embodiment of the present invention has been illustrated in the lforegoing specification, it is not intended to be limited thereto but it is contemplated that it includes vall modifications and embodiments within the spirit and scope of the appended claims.

We claim:

l1. A pump comprising: a cylindrical core removably xed to a stationary shaft; a length of elastic tubing wrapping around the cylindrical surface of said core; inlet and outlet means for said tubing; a source of uid in communication with said inlet means; an external driven ring mounted for rotation about said core; means or driving said driven ring; a rst eccentrically i disposed cylindrical pocket in said externalring; 'an internal ring mounted in said first pocket and attached to said external ring for rotation about said core; means for rotatively adjusting said internal ring in said first pocket; a second eccen'- trically disposed cylindrical pocket in said internal ring; a roller bearing mounted in said second pocket and attached to said internal ring for rotation about said core; a freely rotatable compressor ring mounted for iioating concentric contact with the internal circumference of said roller bearing and for floating eccentric contact with the outwardly disposed external wall of said length of tube; said core and said tube being positioned in cooperating relationship with said compressor ring wheieby in operation said compressor ring will progressively collapse said length of tube inwardly against said core.

2. In combination in a pump of the class described: a xed cylindrical core; a length of elastic tubing entirely encircling said core; and movable compressor means encircling said core and adapted to be moved eccentrically thereon for progressively collapsing said tubing inwardly against said core.

3. In combination in a pump of the class described: a fixed cylindrical core; a length of elastic tubing around said core; inlet and outlet means for said tubing; a source of fluid in communication with said Yinlet means; an external eccentric member and an internal eccentric member arranged for rotation about said core; a ring arranged for freely iioating concentric contact with said internal member and for freely floating eccentric contact with said length of tubing, whereby said ring will progressively collapsesaidlength of tubing inwardly against said core, in operation, and thereby expel said fluid through said outlet means.

4. The combination of claim 3 that includes: means for readily removing and replacing said core, whereby said tubing may be replaced with tubing of a diierent diameter; means for rotatively adjusting the position of said internal member with respect `to the position of said external member, whereby said ring will be in floating eccentric contact with tubing of said different diameter.

5. The combination of claim 3 that includes: an annular friction reducing member positioned between said ring and said internal member.

DAVID T. JAMES. ARTHUR J. RAWSON.

REFERENCES CITED The following references are oi' record in the file of lthis patent:

UNITED STATES APATENTS Number Name Date 2,015,574 Webb Sept. 24, 1935 2,414,355 Bogoslowsky Jan. 14, 1947 2,537,673 James Jan. 9, 1951

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