MXPA99003971A - Improved accuracy peristaltic pump - Google Patents

Abstract

A liquid delivery device which controls the flow of liquid from a liquid reservoir includes a resilient tubing having a wall with a substantially cylindrical cross section defining a flow lumen. The flow lumen is in fluid communication with the reservoir. A compression member selectively compresses a lengthwise segment of the cylindrical wall to collapse the flow lumen and releases the lengthwise segment to open the flow lumen. An elastomeric sleeve envelopes greater than half an outer diameter of the cylindrical cross section of the resilient tubing along at least a portion of the lengthwise segment of the cylindrical wall. The elastomeric sleeve biases the lengthwise segment of the resilient tube to restore it to its substantially cylindrical cross section when the compression member releases the lengthwise segment.

Description

BACKGROUND OF THE INVENTION Technical Field The present invention relates to liquid delivery devices for controlling the flow of liquid from a liquid reservoir, and more particularly to a peristaltic pump of improved accuracy.

Background of the Technique Peristaltic pumps are particularly suitable for use in accurately measuring and instilling fluids, such as medications in the bodies of hospital patients, Heminway, U.S. Patent No. 4,893,991, describes a linear type of peristaltic pump. Natwick, U.S. Patent No. 5,055,001, describes a peristaltic pump valve / plunger type. Galea, U.S. Patent No. 3,999,891, describes a rotary type peristaltic pump.

Each of these peristaltic pumps operates to push liquid through an elastic pipe, which is typically made of a flexible plastic material, such as polyvinyl chloride or the like, the pipe is repeatedly compressed and expanded along a length of defined section of the pipe Ref. 029991 Either you expand or "come back" simply because of your internal c. A known problem with this type of pump is that the portions of tubing, which compress and expand intermittently tend to fatigue over time. As a result, the pipe is less able to return * to its original cross-section when it is released, the volume of the pipe decreases along the critical segment of the pump and therefore the accuracy of the pump decreases. The Patent .S. No. 4,893,991, indicates that such pumps have been found to exhibit nothing less than a 10% drop in the flow rate over a 24-hour period.

The prior art has recognized this deficiency in peristaltic pumps and has tried at least three ways to solve the problem. First, Heminway, U.S. Patent No. 4,893,991, attempts to improve the accuracy of the pump by preventing the portion of elastic tubing, which is subjected to compression and expansion assuming a cylindrical configuration in the expansion. That is, the pistons which compress and expand the pipe are designed to keep the pipe segment in an oval cross section, even in full expansion. A major problem with the solution enunciated in Heminway is that it requires very precise * tolerances with the pistons in the retracted position, so that the pipe is expanded to A cross section is used to e in order for it to operate at exact proportions and volumes.

In addition, because the pipe is not able to assume its full circular cross section, and therefore its maximum volume, Heminway unduly limits the proportion of liquid that can be pumped.

Natwick, U.S. Patent Ho. 5, 055, 001, proposes an even more complicated solution to improve the accuracy of peristaltic pumps. Natwick proposes that the range of diametral compression of the tube be from approximately 15% with the piston retracted to approximately 85% with. In the extended stroke, Natwick demonstrates that since the pipeline does not need to be restored to a completely uncompressed condition, changes in the elasticity of the flexible pipe due to continuous use and repeated compression have much less effect on the volumetric capacity of the pump. In addition, because the plunger does not fully compress the pumping portion of the pipe, the pipe is subjected to less fatigue. Natwick also teaches providing mechanical pipe forms placed on each side of the plunger, which extend to reform the pumping portion of the pipe, since the plunger retracts and the pipe fills with fluid. Heminway in that it limits the volume of the pipe used for pumping and therefore limits pump performance. In addition, the shapes of the pipe are complex mechanical structures, which create an additional path for the potential failure of the pump. In addition, the mechanical forms taught at Natwick require a number of potentially expensive parts and complicate the assembly of the pump.

Mannes, U.S. Patent No. 4,585,442, describes an intravenous infusion rate controller, which operates in an elastic pipe, which rests on a channel between a pair of elastic bands. The elastic bands act on opposite sides of the outer diameter of the pipe in a compressed state to assist in the restoration of the pipe to its original cross-section in the expansion. In this way, the elastic bands inhibit the tendency of the tube to "flatten" and return to only an oval cross section, which reduces the accuracy of the ratio controller. Unluckily, the elastic bands act on only two discrete points in trying to restore the pipe to its original shape. In addition, the space between the elastic bands must be maintained to more precise tolerances to prevent the elastic bands compressing the pipe in an oval cross section if the bands are too close or fail to restore the tube to its circular cross section if the bands are too far from each other.

The present invention relates to overcoming one or more of the problems discussed above.

B pVE DESCRIPTION D T, A INVENTION A first aspect of the invention is a liquid supply device, which controls the flow of liquid from a liquid reservoir. The liquid delivery device includes an elastic tubing having a wall with a substantially cylindrical cross-section defining a flow lumen. The flow lumen is in fluid communication with the reservoir. A compression member selectively compresses a longitudinal segment of the cylindrical wall to crush the flow lumen and release the longitudinal segment to open the flow lumen. An elastomeric sleeve covers more than half the outer diameter of the cylindrical cross section of the elastic pipe along at least a portion of the longitudinal segment of the cylindrical wall. The elastomeric sleeve biases the longitudinal segment of the elastic tube to restore it to its substantially cylindrical cross section when the compression member releases the longitudinal segment.

The elastomeric sleeve, in the relaxed state, has an internal diameter smaller than an outer diameter of the elastic pipe. The sleeve also has an opening substantially linear longitudinal along less than half the cross section of the sleeve, so that a portion of the elastic pipe can be received longitudinally inside the elastomeric sleeve with more than half the diameter of the cross section of the covered pipe by the cuff. Since the longitudinal segment of the elastic tube is crushed, the opening of the elastomeric sleeve is expanded to release the longitudinal segment of the tube. The liquid delivery device further preferably includes an integral handle along the length of the elastomeric sleeve and a clamp for holding the handle to fix the position of the elastomeric sleeve relative to the compression member.

A second aspect of the invention is a peristaltic pump for supplying a liquid flow from a reservoir through an extended elastic line. The elastic tubing has a wall with a substantially cylindrical cross-section defining a flow lumen, the flow lumen being in fluid communication with the reservoir. The peristaltic pump comprises an extended elastomeric sleeve which, in a relaxed state, has an internal diameter less than an external diameter of the elastic tubing. The elastomeric sleeve has a substantially linear longitudinal opening along less than half the cross section of the sleeve, As a result, a portion of the pipe may be longitudinally inserted into the elastomer sleeve with more than half the diameter of the cross section of the pipe covered by the sleeve. A plurality of spaced oscillating pistons are arranged substantially linearly along the elastomeric sleeve. The oscillating pistons extend and retract in relation to the elastomeric sleeve. An anvil is placed on the opposite side of each of the plurality of plungers, adjacent to the opening of the elastomeric sleeve and spacing of the pistons so that, with the elastic tubing received in the elastomeric sleeve, the oscillating pistons crush the flow lumen against the anvil with the extended pistons and do not crush the flow lumen. with the retracted pistons. Since the pistons retract to no longer crush the flow lumen, the elastomeric sleeve biases the elastic tubing received therein to its substantially cylindrical cross-section. Since the section of the elastic pipe is crushed, the opening of the elastomeric sleeve expands to release the elastic pipe and the elastic pipe is in direct contact with the anvil. The elastomeric sleeve preferably includes an integral handle along its length and the peristaltic pump preferably includes a clamp for holding the handle to fix the position of the elastomeric sleeve relative to the pistons. JE1 elastic tube can be kept in one position in re ac n a m only by the elastomeric sleeve.

In a preferred embodiment, the elastomeric sleeve, in cross section, is an extended semicircle with a longitudinal handle extending along each end of the extended semicircle and the peristaltic pump includes clamps for holding the handles to fix the position of the elastomeric handle in relation to the emboli.

A third aspect of the present invention is an elastomeric sleeve for use in a liquid delivery device. The liquid supply device controls the flow of liquid from a liquid reservoir through an elastic line by a compression member in a selective manner that compresses and releases a longitudinal segment of the line to crush and restore a lumen of the line. The elastomeric sleeve consists of an extended side wall which, in a relaxed state, has an internal diameter slightly smaller than an outer diameter of the elastic pipe and a substantially linear longitudinal opening of a width less than half the cross section of the wall side. A longitudinal handle extends from the side wall. The side wall and the handle are formed integrally from a single piece of elastomer.

The cuff is used to present the majority of the wall of the elastic pipe to a uniform compression, which serves to bias and restore the pipe to its substantially circular cross section. In this way, the segment of the pipeline subjected to compression and expansion. pumps liquid at a constant rate for extended periods of time. In addition, the sleeve holds the tubing securely in a desired position relative to the compression member or plunger and the anvil facilitates loading of the tubing in the pump device and keeps the tubing safe during pumping. The opening extended in the sleeve expands during compression of the segment of the pipe, so that the pipe directly connects the anvil, which causes compression of the pipe between the rigid anvil and the plunger. This decreases the amount of energy needed to crush the lumen (as opposed to having to compress the complete elastomeric sleeve between the plunger and the anvil), thereby improving pump efficiency. In addition, the sleeve is easily manufactured by cheap materials and is easy to place.

Brief Description of OH t) u oa FIG. 1 is a perspective view of a peristaltic pump housing including an elastomeric sleeve according to the present invention; Fig. 2 is a cross-sectional view taken along line 2-2 of Fig. 1 with the door closure of the pump case and a plunger-in a retracted position; Fig. 3 is the same as in Fig. 2, only that the plunger is shown in an extended position; Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 1 showing the elastomeric sleeve and elastic tubing operatively associated with the linear peristaltic pump apparatus; Fig. 5 is an alternative embodiment of Fig. 4 showing a valve / plunger of a periettal pump replacing the linear periettal pump of Fig. 4 and with an alternative embodiment of the elastomeric sleeve; Fig. 6 is a cross-sectional view taken along line 6-6 of Fig. 5; Y a g. it is a line in cross section or along line 7-7 of Fig. 5.

Detailed Description of the Preferred Modality A peristaltic pump of improved accuracy 10 is shown in a perspective view in Fig. 1. Most of the features not important to the understanding of this invention, such as controls, locking mechanisms and the like have been omitted by the reason for clarity. The improved accuracy peristaltic pump 10 includes a box base 12 and a box door 14 joined by a hinge 16. An anvil 17 is attached to an inner surface of the box door 14 and extends longitudinally of the door 14. The door 14 further includes a pair of annular apertures 18, 20 on its side walls of the upper part and lower part. While the specific embodiment described herein is of a peristaltic type pump, the elatomeric sleeve can also provide its numerous advantages in other flow control devices, such as the intravenous infusion rate controller described in Mannes, U.S. Pat. No. 4,585,442, the description of which is incorporated by reference.

An elastomeric sleeve 22 is attached to a part 24 within the box base 12 and extends the length of the box base 12. The elastomeric sleeve 22 is positioned in relation to the anvil 17, so that with the door 14 closed , the surface of the anvil 17 is aligned with an extended opening 26 of the elastomeric sleeve 22. As seen in Figures 1 and 2, the elastomeric sleeve 22 consists of a substantially cylindrical side wall 30 with the longitudinal opening 26 separated from the side wall. . A pair of handles 32, 34 extend longitudinally along the elastomeric sleeve 22 and project tangentially adjacent the longitudinal opening 26. Referring to Figure 2, "the elastomeric sleeve in cross section is an extended semicircle with each handle 32, 34 extending tangentially along each extreme of the semicircle: the elastomeric sleeve 22, which includes the handles 32, 34, is formed integrally from a single piece of a suitable, elastic, deformable elastomer, such as rubber, preferably a vulcanization silicon at room temperature (RTV).

The elastomeric sleeve 22 is dimensioned in such a way that the internal diameter of the cylindrical side wall is slightly smaller than the external diameter of the elastic pipe 28. Furthermore, the width of the extended opening 26 is smaller than a half of the cross section of the elastomeric sleeve 22. e is in a manner, since, as shown in Figure 1, the elastic pipe 28 is held in place. As best shown in Figure 2, the elastomeric sleeve 22 biases the elastic pipe 28 to restore it 5 to a substantially circular cross-sectional shape, wherein the flow lumen 42 is not limited and the plunger 40 is limited. Referring to Figure 2 and as shown with respect to the handle 34 in Figure 1, the handles 32, 34 are secured by extended clamps 44. As seen in Fig. 2, the plunger 40 is driven by a cam 46 mounted eccentrically to a drive shaft 48, the cam resides in a collar 50 attached to the plunger 40. In Figure 2, the plunger is in a retracted position. The plunger 40 is illustrated in its position fully extended in Figure 3. Here the plunger 40 is shown to have completely collapsed the lumen 42 of the elastic pipe 28. In addition, the plunger 40 causes the extended opening 26 to expand and release the pipe 28. From this In this manner, the pipe 28 is compressed directly against the anvil 17 as it disengages from the elatomeric sleeve 22.

In Figure 4, the door 14 is closed and the elastic pipe 28 and the sleeve 22 are in a working position in relation to the anvil 17 and the pistons 40. The pistons 40 extend and retract consecutively in relation to the pipe 28 m ngu or om r for u to rav s of lumen 42 as indicated by arrow 52. The operation of a linear peristaltic pump as illustrated in Figure 4 is described in detail in Heminway, U.S. Pat. No. 4,893,991, the description of which is incorporated herein by reference. The mechanism of the plunger illustrated in Figure 4 differs from that illustrated in Figures 2 and 3 in that instead of having eccentric cams 54 mounted within a collar 50 * to direct the plunger between its extended and retracted position, the springs 56 bias the pistons towards a retracted position and the eccentric cams 54 extend the plungers 40 as they revolve around the propeller shaft 42.

Fig. 5 illustrates another embodiment of the elastomeric sleeve 22 in conjunction with a perietáltica type valve / plunger pump. The elatomeric sleeve 22t does not include the extended handles 32, 34, but is in any case different identical to the elastomeric sleeve 22 described above with respect to Figures 1-4. In this mode, the pipeline elastic resides within the elastomeric sleeve 22 ', and is held in place by a length of the elastomeric sleeve 22 ', which is not subject to compression, as illustrated in Figure 6. When made to compree, I play as described above with respect to Figure 3, the sleeve elastomeric 22 'disengages the elastic pipe 28 so that You can buy rec rec e with the anvil. Because of the absence of the longitudinal handles 32, 34, the sleeve 22 'must be secured to the box in some different way. For example, the ends of the sleeve can be fixed to the box. Also, although not illustrated in Figure 5, the elastomeric sleeve 22 'does not need to extend continuously between the plunger 56 and the valves 58. The elastomeric sleeve needs only to extend along a portion of the compressed pipe a sufficient distance to restore the portion of the pipe back to the substantially cylindrical cross-section.

The improved accuracy peristaltic pump shows an elastomeric sleeve, which covers more than half the outer diameter of an elastic pipe to bias the pipe to a substantially cylindrical cross-section in a relaxed state. By providing substantially uniform compression near the periphery of the elastic pipe, the elastic pipe is repeatedly restored securely to the substantially cylindrical shape. Therefore, the elastomeric sleeve ensures the continuous accuracy of a liquid delivery device, such as a peristaltic pump that controls the fluid flow by compression and repeated release of an elastic line. The elastic elasto sleeve also secures the elastic tubing, which both aid in retention plunger and the anvil and also provides a convenient way for securing the tube, be properly loaded in the pump housing prior to a liquid supply operation. Since the sleeve releases the pipe during the extension of the plunger, the pipe is compressed directly against the anvil 17, minimizing energy consumption by the pump. In addition, these numerous advantages are provided by an elastomeric sleeve that is economically manufactured by a variety of elastomers and placed in a pump for minimal cost.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which the member refers.

Having described the invention as above, the content of the following is claimed as property.

Claims (12)

1. A liquid supply device "for controlling the flow of liquid from a liquid reservoir, characterized in that the liquid supply die comprises: an elastic pipe having a wall with a substantially cylindrical cross-section defining a flow lumen, the flow lumen being in fluid communication with the reservoir; a compression member selectively compresses a longitudinal segment of the cylindrical wall to crush the flow lumen and release the longitudinal portion to open the flow lumen; Y an elastomeric sleeve covering more than half the external diameter of the cross section of the elastic pipe along at least a portion of the longitudinal segment of the cylindrical wall, the elastomeric sleeve biases the longitudinal segment of the elastic tube to its cross section substantially cylindrical when the compression member releases the longitudinal segment.

2. The liquid supply device according to claim 1, characterized in that the elastomeric sleeve, in relaxed state, has an internal diameter smaller than an external diameter of the elastic pipe, the elastomeric sleeve furthermore has a substantially linear longitudinal opening of a width along less than half of the cross-section of the sleeve, so that a portion of the elastic pipe may be received longitudinally within the elastomeric sleeve with more than half the diameter of the cross section of the pipe covered by the sleeve .

3. The liquid supply device according to claim 2, characterized in that the longitudinal opening is of a sufficient width that, • as the longitudinal segment of the elastic pipe collapses, the longitudinal opening expands to release the longitudinal segment of the elastic pipe.

4. The liquid supply device according to claim 1, characterized in that it further comprises an integral handle along the length of the elastomeric sleeve and means for holding the handle to fix the cuff position and astom r in re ac n a m em e r compression.

5. A peristaltic pump for supplying a liquid flow from a reservoir through an extended elastic tubing having a wall with a subetanially cylindrical cross-section defining a flow lumen, the flow lumen is in fluid communication with the reservoir, characterized because the peristaltic pump comprises: an extended elastomeric sleeve wh in a relaxed state, has an inner diameter smaller than an outer diameter of the extended elastic pipe, the elastomeric sleeve has a substantially linear longitudinal opening of a width less than half the cross section of the sleeve, so that a portion of the elastic pipe can be received longitudinally within the elastomeric sleeve with more than half the diameter of the cross section of the pipe covered by the sleeve; a plurality of spaced oscillating plungers arranged substantially linearly along the elastomeric sleeve, the oscillating plungers extend and retract in relation to the elastomeric handle; a plurality of plungers adjacent to the linear opening of the elastomeric sleeve and spacing of the plungers so that, with the elastic tubing received in the elastomeric sleeve, the oscillating plungers crush the flow lumen against the anvil with the plungers extended and do not crush the lumen of flow with retracted emboli. therefore, since the pistons retract to no longer crush the flow lumen, the elastomeric sleeve biases the elastic tubing received therein to its substantially cylindrical cross-section.

6. The peristaltic pump according to claim 5, characterized in that the longitudinal opening is of sufficient width that, since the longitudinal segment of the elastic pipe is crushed, the longitudinal opening expands to release the elastic pipe and the elastic pipe is in direct contact with the anvil.

7. The peristaltic pump according to claim S, characterized in that it comprises an integral handle along the length of the elatomeric sleeve and He listened to me for his handle to assemble the elaeomeric sleeve in relation to the pistons.

8. The peristaltic pump according to claim 7, characterized in that the elastic pipe is held in a position in relation to the pistons and the anvil substantially only by the elastomeric sleeve.

9. The peristaltic pump according to claim 5, characterized in that the elastomeric sleeve, in transverse section, is an extended semicircle with a longitudinal handle that extends tangentially along each end of the extended semicircle, the peristaltic pump further comprises means to hold the handles to fix the elastomeric sleeve pore in relation to the pistons.

10. An elaeomeric sleeve for use in a liquid delivery device, which controls the flow of liquid from a liquid reservoir through an elastic line through a compression member that selectively compresses and releases a longitudinal segment of the line for crush and restore , elastomeric sleeve comprises: an extended side wall which, in a relaxed state, has an internal diameter slightly smaller than an outer diameter of the elastic pipe and a substantially linear longitudinal opening of a width less than half the cross section of the side wall; Y a longitudinal handle extending from the side wall.

11. The elastomeric sleeve according to claim 10, characterized in that the side wall and the handle are formed integrally from a single piece of elastomer.

12. The elastomeric sleeve according to claim 10, characterized in that it further comprises a pair of longitudinal handles, each extending tangentially from the side wall along one side of the longitudinal opening. A liquid supply device which controls the liquid flow of a liquid reservoir includes an elastic tubing having a wall with a substantially cylindrical transverse section defining a flow lumen. The flow lumen is in fluid communication with the reservoir. A compression member selectively "compresses a longitudinal segment of the cylindrical wall to crush the flow lumen and releases the longitudinal segment to open the flow lumen." An elastomeric sleeve covers more than half the external diameter of the cylindrical cross section. of the elastic tubing along at least a portion of the longitudinal segment of the cylindrical wall The elastomeric sleeve biases the longitudinal segment of the elastic tube to restore it to its cylindrical transverse section substantially when the compression member releases the longitudinal segment.