Peristaltic pump

Abstract

Provided herein is a peristaltic pump comprising: a rotatable drive plate; a closed-loop channel; a fluid inlet at a first location along the channel; a fluid inlet at a first location along the channel, a fluid outlet at a second location along the channel spaced apart from the first location wherein a first portion of the channel extends between the fluid inlet and the fluid outlet, a first portion of the channel extends between the fluid outlet and the fluid inlet, and a second portion of the channel, separate from the first portion of the channel, extends between the fluid outlet and the fluid inlet; a flexible membrane extending between the fluid inlet and the fluid outlet and fluidly connecting the fluid inlet and the fluid outlet, the flexible membrane defining a closed fluid path between the fluid inlet and the fluid outlet along the first portion of the channel; and a first rolling body, the first rolling body is limited between the channel and the driving plate, so that rotation of the driving plate causes the first rolling body to traverse the channel, the first rolling body causes downward deflection of the flexible film when passing along the flexible film, and the second rolling body causes downward deflection of the flexible film when passing along the driving plate. The fluid outlet is disposed within the closed fluid path to contract the closed fluid path when fluid within the closed fluid path is displaced from the fluid inlet to the fluid outlet. Advantageously, the present invention provides a planar peristaltic pump having a drive plate covering the fluid path, allowing assembly from top to bottom by components assembled along a single vertical axis.

Description

Background of the Invention Technical Field

[0001] The invention relates to a peristaltic pump. Background Art

[0002] Peristaltic pumps are well known in the art. These peristaltic pumps are particularly useful in applications involving contact with the pumped liquid. Peristaltic pumps apply moving pressure along the outside of the catheter, never contacting the liquid being transported. Peristalsis is achieved by transporting a certain volume of liquid in sequence. As a result, a pumping action is generated by the suction force generated at the inlet, sucking in the liquid to be pumped.

[0003] A typical peristaltic pump has a rotating rotor or disk with a plurality of circumferentially spaced rollers. A liquid conduit is arranged to extend around the circumference of the rotating rotor or disk. As the rotor or disk rotates, the rollers move along the conduit in a press-engagement manner through a "wiping" action, actively displacing the liquid trapped in front of each roller. The rollers transport the liquid from the inlet of the pump to the outlet of the pump. The rollers disengage from the conduit at the outlet and rotate from the outlet to the inlet to start a new pumping cycle.

[0004] Peristaltic pumps are widely used in medical applications, for example, where sterility of the pumped liquid must be maintained. In addition, peristaltic pumps can be used for small volumes and are mechanically simple. Even with all these advantages, size constraints and ease of manufacturing may limit their usefulness. Summary of the invention

[0005] A peristaltic pump is provided herein, comprising: a rotatable drive plate; a closed-loop channel; a fluid inlet located at a first position along the channel; a fluid outlet located at a second position along the channel spaced apart from the first position, wherein a first portion of the channel extends between the fluid inlet and the fluid outlet, and a second portion of the channel, separated from the first portion of the channel, extends between the fluid outlet and the fluid inlet; a flexible membrane extending between and fluidically connecting the fluid inlet and the fluid outlet, the flexible membrane defining a closed fluid path between the fluid inlet and the fluid outlet along the first portion of the channel; and a first roller, the first roller being restrainedly disposed between the channel and the drive plate so that rotation of the drive plate causes the first roller to traverse the channel, the first roller causing downward deflection of the flexible membrane as it passes along the flexible membrane to contract the closed fluid path when displacing fluid within the closed fluid path from the fluid inlet to the fluid outlet. Advantageously, the present invention provides a planar peristaltic pump having a drive plate covering the fluid path, thereby allowing top-down assembly with components assembled along a single vertical axis.

[0006] References to liquids and fluids are interchangeable herein and the present invention is intended to work with incompressible fluids or liquids.

[0007] These and other features of the present invention will be better understood through a study of the following description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A peristaltic pump formed in accordance with the present invention is shown.

[0009] Figure 2 Shows Figure 1 A peristaltic pump with the shroud removed.

[0010] Figure 3 Shows Figure 2 An assembly with the motor removed.

[0011] Figure 4 Shows Figure 3 An assembly where the drive plate is removed and the optional cage is used.

[0012] Figure 5 Shows Figure 3 Assembly with the drive plate removed and the optional cage not used.

[0013] Figure 6 A channel with a membrane that can be used in the present invention is shown.

[0014] Figure 7 Shown without membrane Figure 6 channel.

[0015] Figure 8 The invention shows a substrate formed in the vicinity of the motor support. Figure 6 channels and membranes.

[0016] Fig. 9 yes Figure 6 Top plan view of the channel and membrane.

[0017] Figure 10-13 The transition section is shown Figure 6 channels and membranes.

[0018] Fig.14 and Fig.15 is a partial cross-sectional view of a peristaltic pump according to the present invention.

[0019] Fig.16 is a cross-sectional view of a channel and membrane arrangement that may be used in the present invention.

[0020] Fig.17 Is has Fig.16Perspective cross-sectional view of the substrate of the channel and membrane arrangement.

[0021] Figure 18-Figure 20 The function of a peristaltic pump formed according to the present invention is schematically illustrated. DETAILED DESCRIPTION

[0022] Referring to the drawings, a peristaltic pump is shown and indicated by reference numeral 10. The peristaltic pump 10 generally includes a rotatable drive plate 12, a closed-loop channel 14, a flexible membrane 16, and at least one roller 18. The flexible membrane 16 fluidly connects a fluid inlet 20 located at a first position along the channel 14 with a fluid outlet 22 located at a second position along the channel 14 spaced from the first position to define a closed fluid path 24 between the fluid inlet 20 and the fluid outlet 22. The at least one roller 18 is captively disposed between the channel 14 and the drive plate 12 such that rotation of the drive plate 12 causes the at least one roller 18 to traverse the channel 14, the at least one roller 18 deflecting the flexible membrane 16 downwardly as it passes along it to contract the closed fluid path 24 while displacing fluid within the closed fluid path 24 from the fluid inlet 20 to the fluid outlet 22.

[0023] The drive plate 12 is annular with a central opening 13 in which the drive shaft 26 is received. Fig.14 As shown, the peristaltic pump 10 may include a motor 28 coupled to a drive shaft 26 to rotate the drive plate 12 about an axis of rotation R. The motor 28 may be mounted on top of a motor support 30 on a base plate 32, the motor support being located near the drive plate 12. In this manner, the motor 28 may extend cantilevered to the drive shaft 26. The drive shaft 26 may be coupled to the drive plate 12 in any known manner to transmit rotational force thereto, including having one or more keys received in corresponding apertures in the drive plate 12, or vice versa, or a combination thereof. By using a key / aperture arrangement, the motor 28 is easily assembled to or removed from the drive plate 12, wherein the drive shaft 26 is inserted or withdrawn from the central opening 13 of the drive plate 12.

[0024] The motor support 30 may include a bracket 34 for receiving the motor 28. In addition, a shroud 36 may be provided for shrouding the motor 28 on top of the motor support 30. The shroud 36 may be provided with a plurality of retaining apertures 38 formed to snap-engage retaining detents 40 located on the motor support 30. To provide additional securement, at least one barrier 42 may be provided on the base plate 32, including on a side of the drive plate 12 opposite the motor support 30, having retaining detents 40 that may snap-engage with the retaining apertures 38 of the shroud 36.

[0025] like Figure 3 As shown, with the motor 28 removed, the drive plate 12 is exposed. Figure 14-15 As shown, the drive plate 12 has a first surface 44 facing the channel 14. Preferably, the channel 14 is a closed loop substantially located in a single plane P, wherein the first surface 44 is substantially parallel thereto. At least one recess 45 is formed in the first surface 44, and at least one roller 18 is seated in the recess. One recess 45 is provided for each roller 18. Figure 14-15 As shown, with at least one roller 18 disposed in the channel 14, the mutual engagement of the at least one roller 18 and the drive plate 12 causes the at least one roller 18 to traverse the channel 14 as the drive plate 12 rotates. With the roller 18 seated in the recess 45, interference is created between the drive plate 12 and the roller 18, wherein rotation of the drive plate 12 causes movement of the roller 18.

[0026] The channel 14 is formed below the drive plate 12 so that the drive plate 12 covers the channel 14. The channel 14 is preferably annular in shape. The first surface 44 of the drive plate 12 preferably has a sufficient diameter to overlap a diametrically opposed portion of the channel 14. This optimally ensures good contact between the at least one roller 18 and the drive plate 12 during traversal of the entire length of the channel 14. In the case where the channel 14 is annular, the at least one recess 45 can rotate around the axis of rotation R at a fixed radius aligned with the channel 14.

[0027] In addition, the drive plate 12 is positioned to exert downward pressure on the at least one roller 18. When the at least one roller 18 moves along the flexible membrane 16, the at least one roller 18 compresses the flexible membrane with the downward pressure. The compression of the flexible membrane 16 causes a constriction of the closed fluid path 24, which is used to trap the liquid to enable it to be positively displaced. The constriction is defined below the contact point of the at least one roller 18 with the flexible membrane 16, wherein the constriction moves along the flexible membrane 16 as the at least one roller 18 moves.

[0028] The channel 14 may also be formed in the substrate 32. Figure 7 As shown, the fluid inlet 20 and the fluid outlet 22 can extend through the substrate 32, be defined by the substrate 32 and / or be a tube extending through the substrate 32. The channel 14 includes two parts: a first part 14A, extending from the fluid inlet 20 to the fluid outlet 22; and a second part 14B, extending from the fluid outlet 22 to the fluid inlet 20. The second part 14B is separated from the first part 14A. The first part 14A and the second part 14B can together cover the entire length of the channel 14.

[0029] The channel 14 includes a side wall 46 that is shaped to support at least one roller 18 for rolling or sliding motion there along. Figure 14-15As shown, in the case where the at least one roller 18 is spherical, the side wall 46 can be arcuate to match the radius of the at least one roller 18. The at least one roller 18 can also be formed into other shapes, such as barrel, cone or block. The side wall 46 can be formed to match the contour of the at least one roller 18, thereby allowing rolling or sliding motion along it.

[0030] The flexible membrane 16 fluidly connects the fluid inlet 20 with the fluid outlet 22 to define a closed fluid path 24 between the fluid inlet 20 and the fluid outlet 22. The fluid inlet 20 and the fluid outlet 22 define an opening communicating with the closed fluid path 24, which is covered by the flexible membrane 16. Figure 6 The liquid introduced through the fluid inlet 20 can be transported to the fluid outlet 22 through the closed fluid path 24 continuously covered by the flexible membrane 16 so as not to contact with the at least one roller 18 .

[0031] The flexible membrane 16 can be formed of an elastomeric or polymeric material, such as silicone (e.g., room temperature vulcanized (RTV) silicone) or polyurethane. Preferably, the flexible membrane 16 is provided with sufficient elasticity and compression memory for contracting the closed fluid path 24, and for substantially restoring its original profile for reopening the closed fluid path 24 after compression. The elastomeric material can be selected based on hardness to achieve the desired function. It has been found that a membrane with a 70 Shore A hardness can be used with the present invention. Pump size, flow rate, and pressure requirements may also affect the selection of hardness.

[0032] The flexible membrane 16 is secured to a portion along the first portion 14A of the channel 14. The flexible membrane 16 may extend between the side walls 46 to define the bottom of the first portion 14A of the channel 14. In the case where the channel 14 is formed in the substrate 32, the flexible membrane 16 may be secured to the substrate 32 along the first portion 14A of the channel 14. The flexible membrane 16 may define the closed fluid path 24 together with adjacent portions of the substrate 32. The substrate 32 may be provided as a single plate, or may be formed of a plurality of joined layers. Fig.16 As shown, in the case of multiple layers, the top layer 32A can be arranged to be located on top of and joined to the lower layer 32B. The lower channel 48 can be undercut in the top layer 32A, following the contour of the channel 14. The lower layer 32B can have a raised ridge 50 formed to extend into the lower channel 48, wherein a groove 52 is formed along the ridge 52. The groove 52 can define the closed fluid path 24 with the flexible membrane 16. The flexible membrane 16 can be domed over the groove 52 to define the closed fluid path 24.

[0033] The top layer 32A and the lower layer 32B can be manufactured separately. For assembly, the flexible membrane 16 can be arranged along the ridge 50, wherein the top layer 32A is mounted to the lower layer 32B. With the ridge 50 received in the lower channel 48, the edge portion 54 of the flexible membrane 16 is captured between the top layer 32A and the lower layer 32B to fix the flexible membrane 16 relative to the channel 14. A retaining ridge 56 can be provided on the top layer 32A, which is formed to press into the edge portion 54 of the flexible membrane 16 to enhance its retention. The top layer 32A and the lower layer 32B can be formed of a polymer material (e.g., a thermoplastic) and joined using any known technique (such as bonding, fusing, etc.).

[0034] Where substrate 32 is a single plate, slot 52 may be formed as a depression extending below sidewall 46 of first portion 14A of channel 14. Flexible membrane 16 may be secured to sidewall 46 (at its lower edge) using any technique such as bonding, fusing, etc.

[0035] like Fig.16 As shown, preferably, a relief 58 is defined around the flexible membrane 16 to define a gap between the flexible membrane 16 and the substrate 32, into which the flexible membrane 16 can flow under compression. The relief 58 can be defined by shaping the contour of the flexible membrane 16, for example by having an inwardly curved portion 58A along the side wall 46, and / or by avoiding full face-to-face contact between the edge portion 54 and the top layer 32A to define the gap 58B.

[0036] The second portion 14B of the channel 14 is formed outside the closed fluid path 24. The channel 14 may have a solid base 60 extending between the side walls 46. The solid base 60 may be formed to match the shape of the corresponding at least one roller 18, thereby continuously extending the contour of the side wall 46. The solid base 60 may be formed in the base plate 32. The second portion 14B serves as a return device to allow the at least one roller 18 to return from the fluid outlet 22 to the fluid inlet 20 to continuously repeat the pumping action.

[0037] There may be a height difference between the first portion 14A and the second portion 14B of the channel 14, in particular due to the thickness of the flexible membrane 16. Preferably, a transition portion 62 is provided at the intersection of the first portion 14A and the second portion 14B to act as a ramp, thereby allowing a gradual transition between the first portion 14A and the second portion 14B. Figure 11-13 As shown, in the case where the second portion 14B is lower than the first portion 14A, the transition portion 62 is ramp-shaped to gradually join the first portion 14A and the second portion 14B, wherein the transition portion 62 has the same profile as the channel 14 .

[0038] When ready for use, the drive plate 12 can be assembled so as not to apply pressure to the at least one roller 18 during storage. Prolonged compression in one or more different points on the flexible membrane 16 can inadvertently cause permanent deformation. If spring mounts 64 and springs 68 are utilized, they can also be assembled when ready for use.

[0039] Additionally, to compensate for any height differences between the first portion 14A and the second portion 14B, and / or to optimally generate a consistent downward pressure on the at least one roller 18, the drive plate 12 may be provided with a spring mount 64 surrounding the central opening 13, which may be secured to the drive shaft 26, such as Figure 14-15 As shown. The drive plate 12 may also be formed with a spring channel 66 formed around the central opening 13. A spring 68 (e.g., a coil spring) is disposed in the spring channel 66 to be pressure-engaged with the spring mount 64. Preferably, the spring 68 is disposed in the spring channel 66 in a compressed manner to prestress the drive plate 12 downward toward the at least one roller 18. This arrangement allows the drive plate 12 to press-engage the at least one roller 18 in the event of a height variation between the first portion 14A and the second portion 14B of the channel 14, and ensures that pressure is consistently applied to the at least one roller 18 to optimally ensure proper compression of the flexible membrane 16. The downward extension of the base plate 12 caused by the biasing force of the spring 68 is limited by contact with the at least one roller 18.

[0040] To provide additional stability, an annular cage 70 may optionally be disposed between the drive plate 12 and the channel 14 around the central opening 13. The cage 70 includes a lower surface 72 facing the channel 14 and an upper surface 74 facing away from the channel 14. At least one seat 76 is formed in the lower surface 72 for receiving the at least one roller 18. An opening 78 may be formed in the upper surface 74 in alignment with the at least one seat 76 to allow a portion of the at least one roller 18 to protrude from the upper surface 74, wherein the at least one roller 18 is seated in the at least one seat 76. The portion of the at least one roller 18 protruding from the opening 78 may be received in the recess 45. The at least one roller 18 also protrudes from the lower surface 72 to be received in the channel 14. A seat 76 and a corresponding opening 78 are provided for each roller 18 and recess 45.

[0041] The holder 70 is rotatable independently of the drive plate 12. More specifically, as discussed above, the drive plate 12 is coupled to the drive shaft 26 to rotate therewith. The holder 70 is not fixed to the drive plate 12, the channel 14, the at least one roller 18, or the drive shaft 26. This allows the holder 70 to rotate while the at least one roller 18 is driven. In addition, the holder 70 can be adjusted using the at least one roller 18 in response to any height changes between the first portion 14A and the second portion 14B of the channel 14. The drive plate 12 moves the at least one roller 18 along the channel 14 without any influence from the holder 70. The at least one roller 18 is captured between the drive plate 12 and the channel 14 independently of the holder 70.

[0042] As will be appreciated by those skilled in the art, any number of rollers 18 may be utilized. As shown, the present invention may utilize three rollers 18. Preferably, in the case of multiple rollers 18, the rollers 18 are evenly spaced around the channel 14, e.g., with recesses 45 evenly spaced around the first surface 44 of the drive plate 12. The even spacing provides more even pumping and more evenly distributed support for the drive plate 12 (thereby avoiding eccentric loading).

[0043] Figure 18-Figure 20 The operation of the peristaltic pump 10 is shown using three rollers 18, which are designated A, B, and C. Fig.18 In the position shown, and considering a clockwise rotation, roller A enters the first portion 14A of channel 14 to pass through inlet 20 at the start of a pumping cycle. As roller A enters the first portion 14A, a pumping cycle is initiated, wherein roller A causes compression of flexible membrane 16 to contract and close fluid path 24, as shown in FIG. Fig.16 14A, and a volume of liquid is trapped between rollers A and C. Rollers A, B, and C each cause a contraction of the closed fluid path 24 while moving along the flexible membrane 16 to transport liquid from the fluid inlet 20 to the fluid outlet 22. Roller C is located in the middle along the first portion 14A, and transports the liquid trapped between rollers C and B toward the fluid outlet 22. The movement of roller C from the fluid inlet 20, along with the contraction of the closed fluid path 24, causes suction to be generated at the fluid inlet 20 to draw liquid from the fluid inlet 20 into the closed fluid path 24. The liquid drawn in by the movement of roller C will be trapped between rollers A and C with further clockwise rotation. Roller B is shown as crossing the fluid outlet 22, so that the liquid that has been trapped between rollers B and A is discharged through the fluid outlet 22. Roller B enters the second portion 14B of the channel 14 to return to the fluid inlet 20. In this position, roller B prevents the liquid trapped between rollers C and B from draining away.

[0044] Fig.19The rollers A, B, and C are shown Fig.18 Here, roller A is now completely within first portion 14A, continuously causing constriction of closed fluid path 24 while conveying liquid trapped between rollers B and A toward fluid outlet 22. Roller A also creates suction at fluid inlet 20 to draw liquid into closed fluid path 24. Roller C continues to traverse first portion 14A toward outlet 22, also continuously causing constriction of closed fluid path 24. Fig.19 In the position shown in FIG. 1 , with roller B passing through fluid outlet 22, the closed fluid path 24 between roller C and fluid outlet 22 is unobstructed, thereby allowing liquid to be discharged through fluid outlet 22 under the moving force of roller C. As the guide roller enters the second portion 14B, discharge through fluid outlet 22 is allowed. Fig.19 In the position shown, as roller C approaches further toward fluid outlet 22, roller C will continue to push liquid through fluid outlet 22. Roller B is located midway along second portion 14B, returning to fluid inlet 20.

[0045] Fig. 20 The rollers A, B, and C are shown Fig.18 Here, roller A is at Fig.18 The roller C occupies the position of roller B in Fig.18 The roller A occupies the position of roller C in Fig.18 Roller B begins a new pumping cycle in which the closed fluid path contracts as liquid is trapped between rollers B and A. Roller A continues to transport the liquid trapped between rollers A and C toward the fluid outlet 22. Roller C completes its pumping cycle, causing the entire amount of trapped liquid to be discharged through the fluid outlet. Roller C enters the second portion 14B on its way back to the fluid inlet 20, while causing a blockage of the fluid outlet 22 for the liquid trapped between rollers A and C.

[0046] As will be appreciated by those skilled in the art, a variety of liquids, including liquid medications, solutions, or bodily fluids, may be delivered by the peristaltic pump 10. The peristaltic pump 10 is well suited for small and micro volume applications.

[0047] A variation of the peristaltic pump 10 is possible in which, for example, the flexible membrane 16 is provided in the form of a tube. This allows the flexible membrane 16 to be arranged along the channel 14 to define a closed fluid path 24.

Claims

1. A peristaltic pump, comprising: A rotatable drive plate; Closed-loop channel; a fluid inlet located at a first position along the passage; a fluid outlet located at a second location along the channel spaced apart from the first location, wherein a first portion of the channel extends between the fluid inlet and the fluid outlet, and a second portion of the channel separate from the first portion of the channel extends between the fluid outlet and the fluid inlet; a flexible membrane extending between and fluidly connecting the fluid inlet and the fluid outlet, the flexible membrane defining a closed fluid path between the fluid inlet and the fluid outlet along the first portion of the channel; and, a first roller, the first roller being captively disposed between the channel and the drive plate such that rotation of the drive plate causes the first roller to traverse the channel, the first roller causing downward deflection of the flexible membrane as it passes along the flexible membrane to constrict the closed fluid path while displacing fluid within the closed fluid path from the fluid inlet to the fluid outlet.

2. The peristaltic pump according to claim 1, wherein: The second portion of the channel does not overlap any portion of the closed fluid path.

3. The peristaltic pump according to claim 1, wherein: The drive plate includes a first surface facing the channel.

4. The peristaltic pump according to claim 3, wherein: At least one recess is formed in the first surface, the first roller being seated in the recess.

5. The peristaltic pump according to claim 3, wherein: The first surface has a sufficient diameter to overlap a diametrically opposed portion of the passageway.

6. The peristaltic pump according to claim 1, wherein: The first roller is spherical.

7. The peristaltic pump according to claim 1, wherein: The first roller is barrel-shaped.

8. The peristaltic pump according to claim 1, wherein: The first rolling body is block-shaped.

9. The peristaltic pump according to claim 1, wherein: The first roller is conical.

10. The peristaltic pump of claim 1, further comprising a second roller captively disposed between the channel and the drive plate such that rotation of the drive plate causes the second roller to traverse the channel.

11. The peristaltic pump of claim 1 , further comprising a motor for rotating the drive plate.

12. The peristaltic pump according to claim 1, wherein: The flexible membrane is secured to a portion along the channel.

13. The peristaltic pump according to claim 1, wherein: The channel is generally disposed in a first plane, and wherein the drive plate includes a first surface generally parallel to the first plane.

14. The peristaltic pump according to claim 1, wherein: The flexible membrane together with an adjacent portion of the substrate defines the closed fluid path.

15. The peristaltic pump according to claim 1 further comprises an annular retainer having a lower surface facing the channel and an upper surface facing away from the channel, a first seat being formed in the lower surface for receiving the first roller, and a first opening being formed in the upper surface to align with the first seat to allow a portion of the first roller to protrude from the upper surface when the first roller is seated in the first seat.

16. The peristaltic pump according to claim 15, wherein: The driving plate includes a first surface facing the upper surface, and a first recess is formed in the first surface to receive a portion of the first roller protruding from the upper surface.

17. The peristaltic pump according to claim 16, wherein: The retainer is rotatable independently of the drive plate.

18. The peristaltic pump according to claim 1, wherein: A plurality of rollers are configured to be captively disposed between the channel and the drive plate such that rotation of the drive plate causes the plurality of rollers to traverse the channel, the plurality of rollers being evenly spaced about the channel.

19. The peristaltic pump according to claim 1, wherein: The flexible membrane defines a tube.

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