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EP-4118336-B1 - PERISTALTIC PUMP

EP4118336B1EP 4118336 B1EP4118336 B1EP 4118336B1EP-4118336-B1

Inventors

  • STEWART, ALASTAIR
  • GAO, Xumei

Dates

Publication Date
20260506
Application Date
20210311

Claims (14)

  1. A rotor (10) for a peristaltic pump, the rotor (10) comprising a body (12) for rotation about an axis, the body (12) having a first side and a second side, the body supporting a plurality of spaced first rollers (14A) extending from the body on the first side, the first rollers (14A) positioned at a first common radius from the axis, the body further supporting a plurality of spaced second rollers (14B) extending from the body (12) on the second side, the second rollers (14B) positioned at a second common radius from the axis, characterized in that the first rollers (14A) are arranged to contact the second rollers (14B) within the body (12).
  2. The rotor (10) of Claim 1, wherein: the spacing between the plurality of first rollers (14A) is substantially the same as that between the plurality of second rollers (14B); the first common radius is substantially equal to the second common radius; the position of the plurality of first rollers (14A) is phase shifted with respect to that of the plurality of second rollers (14B); and each of the plurality of first rollers (14A) is arranged to contact two of the plurality of second rollers (14B), and each of the plurality of second rollers (14B) is arranged to contact two of the plurality of first rollers (14A).
  3. The rotor (10) of Claim 2, wherein the rotor body (12) has a generally planar form and is provided with recesses in the first and second side to receive the first and second rollers (14B) respectively, the recesses meeting within the body (12) to allow contact between the first and second rollers (14A, 14B).
  4. The rotor of any preceding claim, including a further plurality of spaced first rollers (14A) extending from the body (12) on the first side, the further plurality of spaced first rollers (14A) positioned at a third common radius from the axis different from said first common radius, additionally including a further plurality of spaced second rollers (14B) extending from the body (12) on the second side, the further plurality of spaced second rollers (14B) positioned at a fourth common radius from the axis different from said second common radius.
  5. The rotor of Claim 4, wherein: the spacing between the further plurality of first rollers (14A) is substantially the same as that between the further plurality of second rollers (14B); the third common radius is substantially equal to the fourth common radius; the position of the further plurality of first rollers (14A) is phase shifted with respect to that of the further plurality of second rollers (14B); and each of the further plurality of first rollers (14A) is arranged to contact two of the further plurality of second rollers (14B), and each of the further plurality of second rollers (14B) is arranged to contact two of the further plurality of first rollers (14A).
  6. A peristaltic pumping unit comprising the rotor (10) of any preceding claim assembled with a first stator (20A) and a second stator (20B), the first stator (20A) having one or more compressible fluid channels (22, 22', 24, 24') arranged to be compressed by said first rollers (14A) and the second stator (20B) having one or more compressible fluid channels (22, 22', 24, 24') arranged to be compressed by said second rollers (14B).
  7. The pumping unit of Claim 6, wherein the rotor body (12) has a generally planar form and the first and second stators (20A, 20B) each has a planar surface on or in which the one or more compressible fluid channels (22, 22', 24, 24') are provided, wherein the rotor body (12) is sandwiched between the first and second stators (20A, 20B) to provide substantially the same compression on the one or more fluid channels (22, 22', 24, 24') of the first stator (20A) as that on the one or more fluid channels (22, 22', 24, 24') of the second stator (20B).
  8. The pumping unit of Claim 7, including an adjuster mechanism to tune the separation between the first and second stators (20A, 20B) in order to adjust the compression on the one or more fluid channels (22, 22', 24, 24').
  9. The pumping unit of any one of Claims 6 to 8, wherein the first stator (20A) includes multiple fluid channels (22, 22', 24, 24'), each of which includes an arcuate portion at or substantially at said first common radius from the axis.
  10. The pumping unit of Claim 9, wherein the arcuate portion is of a length greater than the spacing between the spaced first rollers (14A), such that the arcuate portion is simultaneously compressed by at least two rollers of said plurality of first rollers (14A).
  11. The pumping unit of any one of Claims 6 to 8, wherein the first stator (20A) is at least partly formed by a compressible material forming a substantially planar surface and compressible arcuate portions of multiple fluid channels at different radii, each fluid channel arranged to be compressed by a different plurality of rollers to drive flow in that fluid channel, including one or more recesses in the compressible material shaped and positioned to relieve compression of a particular fluid channel by passage of rollers not in the plurality of rollers arranged to drive fluid flow in that particular fluid channel.
  12. A peristaltic pumping assembly, comprising a plurality of pumping units in accordance with any one of Claims 6 to 11, stacked to align the axis of each rotor (11), including a drive shaft configured to engage and rotate each rotor (10).
  13. A stator for a peristaltic pump, having a body (12) with a planar surface and two or more fluid channels, characterized in that each fluid channel has a compressible arcuate portion on or in the planar surface of the stator, the arcuate portions arranged to be compressed by a plurality of rollers (14A, 14B) mounted on a rotor (10), one of each of the arcuate portions connecting to further portions of the fluid channel extending in a direction away from the planar surface such that one or more of the fluid channels take a three dimensional path within the body of the stator.
  14. A peristaltic pumping unit comprising the stator of Claim 13 assembled with a rotor (10), the rotor supporting or driving a plurality of rollers (14A, 14B), the rollers (14A, 14B) positioned to compress the arcuate portions of said two or more compressible fluid channels.

Description

Field of the invention The present invention relates to a peristaltic pump, in particular a multiplex planar peristaltic pump. The invention also concerns a rotor and a stator for such a pump. Background of the invention A peristaltic pump (also sometimes referred to as a roller pump) is a type of positive displacement pump used for pumping fluids, the fluid contained within a flexible tube mounted in a pump casing or stator. In a typical peristaltic pump, a rotor carries a number of circumferential rollers mounted on bearings, each of which is arranged to compress the flexible tube. As the rotor rotates, a part of the tube is compressed by a roller, thus occluding the tube and forcing the fluid to move through the tube in the direction of movement of the roller. The tube is fabricated from a resilient material and thus reassumes its normal calibre after the compression by the roller ceases. This process of peristalsis mimics many biological systems (such as the action of oesophagus or the gastrointestinal tract). A body of fluid (or bolus) trapped between two successive rollers is thus transported at ambient pressure toward the pump outlet. Typically, peristaltic pumps are employed in the pumping of clean or sterile fluids, as there is no contact between the pump mechanism and the content of the tube. Such pumps are often used in medical applications, such as to pump IV fluids through infusion devices, in haemodialysis systems, or in heart-lung machines to circulate blood during bypass surgery. Peristaltic pumps are also used to pump aggressive fluids and chemicals, including very viscous fluids and high solids slurries, where isolation of the material from the environment is important. Peristaltic pumps may run continuously, or they may be indexed through partial revolutions to deliver smaller amounts of fluid. Aside from the benefits mentioned above, peristaltic pumps offer the advantages of low maintenance, few moving parts, prevention of backflow and siphon, and accurate dosing (as a fixed amount of fluid is pumped per rotation of the rotor). This latter characteristic (the ability to provide a flow rate directly proportional to the driving peristaltic motion) means that the pump can faithfully produce a predefined flow rate without the need for feedback-control by costly flow sensors. Further, as an in-line pump, a peristaltic pump affords the ability to change fluid medium without disrupting flow (unlike pressure driven pumping solutions such as syringe systems or pneumatic pumps). This means that various operations can be performed on the content of a receiving reservoir in real time, e.g. medium top-up, drug addition, gas equilibration, etc. Peristaltic pumps have also been adopted in biological and biochemical analytical workflows for various purposes including transferring of fluids, washing and perfusion. One key application of peristaltic pump is in in-vitro perfusion of biological samples. A number of commercial peristaltic pumps are available on the market. The target flow rate range is usually in the range of (at the minimum) mL/min, primarily useful in tissue-scale/organ-scale continuous perfusion or transient flushing/rinsing of smaller samples. Such pumps use flexible tubing as the fluid carrier, which tends to degrade with time due to abrasion. An alternative to the conventional circumferential roller peristaltic pump is the planar peristaltic pump. This takes the form of a thrust ball bearing assembly, consisting of a rotor disc carrying a ring of stainless steel balls, as illustrated in Figure 1. The rotor 1 is rotated at a particular angular velocity, and the balls are carried in a planar cage disc 3 which provides the required support and spacing. A soft substrate surface layer 2 on rotor 1 provides the friction required to rotate the balls 4, which are arranged to compress and roll on a silicon rubber substrate in which a fluid channel 6 is embedded. Stationary support disc or stator 7 underlies fluid channel 6 and substrate 5. The separation between rotor 1 and stator 7 is arranged such that the compression force exerted by balls 4 occludes fluid channel 6. As roller 1 rotates, all of the balls 4 are rolled in unison, resulting in the fluid trapped in the channel between two adjacent balls 4 being pushed forward. As will be understood, if the velocity of rotor 1 is v, cage disc 3 rotates at v/2, and the only sliding friction in the mechanism is that sustained between balls 4 and cage disc 3. Examples of concepts around the planar peristaltic pump include the disclosure of US patent application no. 2014/0356849 (Vanderbilt University), US patent application no. 2018/0058438 (Novartis AG), US patent application no. 2018/0209552 (Vanderbilt University), European patent application no. 1,662,142 (Debiotech S.A.), US patent application no. 2018/0149152 (Takasago Electric, Inc) and international patent publication WO 2012/048261 (Vanderbilt University). Planar peristaltic pumps allow sma