CN117597513A

CN117597513A - Discharge electrical device, method and system

Info

Publication number: CN117597513A
Application number: CN202280046839.1A
Authority: CN
Inventors: J·詹姆斯; D·迪奥内
Original assignee: NxStage Medical Inc
Current assignee: NxStage Medical Inc
Priority date: 2021-06-30
Filing date: 2022-06-09
Publication date: 2024-02-23
Also published as: EP4363723A1; CA3223175A1; WO2023278116A1; AU2022302967A1; US20230003209A1

Abstract

A peristaltic pump for reducing current flow through a pumping segment, comprising: a center rotor mounted on a center rotation axis; a shoe having a curved surface facing the central rotor; a plurality of rollers mounted along the circumference of the central rotor; and a pumping segment positioned between the curved surface and the central rotor. Each of the plurality of rollers is a member of a roller set, each roller set comprising at least two rollers, the rollers in a particular roller set being physically closer to each other than to the rollers in the other roller sets, and the at least two rollers clamping a portion of the pumped pipe section against the curved surface through a complete rotation of the central rotor.

Description

Discharge electrical device, method and system

Cross Reference to Related Applications

The present application claims priority from U.S. provisional application No.63/216,725 filed on 6/30 of 2021, the entire contents of which are incorporated herein by reference.

Background

In modern medicine, it is very common to use electrically powered medical devices or equipment that are connected to the patient. In addition to the benefits these devices are intended to provide to the patient, they may also present a potential hazard to shock the patient. The current flowing through the patient (referred to as leakage current) may create electrical shocks, for example, problems such as ventricular defibrillation in the patient's heart, and if the patient is in contact with another power source, the medical device may induce ventricular defibrillation in the patient at ground potential or in a patient lying on the ground. It is desirable to design medical devices to reduce leakage current. In particular, it is desirable to provide a pump that reduces or completely blocks leakage current through the pump.

Disclosure of Invention

In some embodiments, leakage current paths may be formed in fluid lines, such as drain lines. Typically, a pump, such as a peristaltic pump, is used to pump fluid through the fluid line. Peristaltic pumps comprise a rotor around which a plurality of rollers are arranged, and which come into contact with a flexible tube and press it against a portion called a pump shoe. Peristaltic pumps according to embodiments of the present disclosure reduce or completely block and prevent leakage current from flowing through a tube serving as a pumping segment by ensuring that conductive fluid in the pumping segment is forced out of certain areas and thereby interrupting the conductive path through the pumping segment.

Drawings

The accompanying drawings, which are incorporated herein and constitute a part of this specification, illustrate exemplary embodiments of the disclosure and, together with the general description given above and the detailed description given below, serve to explain features of embodiments of the disclosed subject matter. The figures are not necessarily drawn to scale. Where applicable, some features may not be shown to aid in describing the underlying features.

Fig. 1A and 1B illustrate peristaltic pumps according to embodiments of the present disclosure.

Fig. 1C illustrates various dimensions of peristaltic pumps according to embodiments of the disclosed subject matter.

Fig. 2A and 2B illustrate peristaltic pumps according to further embodiments of the disclosed subject matter.

Fig. 3A and 3B illustrate peristaltic pumps with pump shoes according to embodiments of the disclosed subject matter.

Figures 4A-4C illustrate peristaltic pumps having pump shoes and pressure cones according to embodiments of the disclosed subject matter.

Fig. 5 shows a peristaltic pump with a larger pump shoe in accordance with an embodiment of the disclosed subject matter.

Fig. 6 shows a process flow for controlling a peristaltic pump according to an embodiment of the disclosed subject matter.

Detailed Description

Embodiments will be described in detail below with reference to the drawings, wherein like reference numerals denote like elements.

Referring now to fig. 1A, a peristaltic pump 100 is shown. In a typical peristaltic pump, the rotor 120 carries a plurality of circumferential rollers (101, 102, 103, 104) which may be bearing mounted, each of which is arranged to compress a flexible tube 130. As the rotor rotates, a portion of the tube is compressed by the roller, thereby blocking the tube and forcing fluid to move through the tube in the direction of movement of the roller. The tube is made of an elastic material so that the normal cross-sectional profile of the tube will resume after compression of the roller has ceased. This peristaltic process mimics many biological systems (such as the action of the esophagus or gastrointestinal tract). Thus, at ambient pressure, the body of fluid (or mass) trapped between two consecutive rollers is transported towards the pump outlet.

Peristaltic pump 100 includes a rotor 120, rotor 120 mounted on a center point or axis 121 and rotatable about center point or axis 121 and positioned proximate a pump shoe 125. As shown by the double-sided arrows in fig. 1A, the rotor 120 and the shoe 125 may move relative to each other such that the gap between the rotor 120 and the shoe 125 may increase or decrease. The shoe 125, the rotor 120, or both may be mounted on a shaft or rod 114, the shaft or rod 114 being inserted into a spring 116 or other biasing mechanism, the spring 116 or other biasing mechanism urging the rotor and shoe toward one another, as shown in fig. 1A. It should be appreciated that in addition to the shoes 125 being biased, a biasing mechanism (such as a spring, electromagnet, linear motor or hydraulic piston, and other mechanisms capable of exerting a force or torque on the axis 121) may also be utilized to bias the central axis 121 of the rotor 120, or to bias the central axis 121 of the rotor 120 instead of the shoes 125.

The central rotor 120 includes a plurality of pumping rollers mounted around its outer circumference. In the embodiment of fig. 1A, separate pumping rollers 101, 102, 103 and 104 are shown, but fewer or more rollers may be present as described in other embodiments of the present disclosure. In one embodiment, rollers 101, 102, 103, and 104 are spaced apart at equal angular intervals around the circumference of rotor 120. Each roller is mounted on its own axis, which allows the roller to rotate. In one embodiment, each of the plurality of axes of the rollers is positioned on the outer circumference of the rotor 120. In other embodiments, the central axis is positioned closer to the center point 121 such that the central axis is not positioned on the outer circumference. Fig. 1A shows the entire circumference of each roller to aid understanding, but it should be understood that typically the entire circumference of the roller or rollers will not be visible as it will be covered by a portion of the rotor 120. Thus, fig. 1A may be considered a schematic view or a partial cross-sectional view showing a roller without obstructions.

Rotor 120 rotates in a clockwise direction in fig. 1A, as indicated by the dashed arrow, to cause the peristaltic pump to pump fluid through the pumping tube segment. A length of flexible hollow tubing is positioned in the space between the rotor 120 and the shoe 125. The portion of the hollow tube is referred to as the pumping tube 130 or pumping tube segment 130. When the pumping segment 130 is so positioned, as the central rotor 120 rotates, the respective pumping rollers 101, 102, 103 and 104 press against the pumping segment 130 at pinch point 135, as shown. As shown in fig. 1A, when the rotor 120 is in the particular angular position shown, there are two pinch points 135 created by the rollers 102 and 103. At each pinch point, the wall of the pumping tube collapses so that all fluid is forced out of the tube at that location. The pinch point migrates along the curved surface 145 of the shoe 125, causing fluid in front of the pinch point to move in the direction of rotation of the rotor 120.

Capital letter a indicates the angular spacing of the rotors along central rotor 120. In the example of fig. 1A, the angular spacing is 90 degrees because the four rollers shown in fig. 1A are equally spaced around the outer circumference of the central rotor 120. As described above, there may be more or less than four rollers. In an embodiment, the angular spacing is 120 degrees.

The pumping segment 130 may be filled with a fluid that is capable of conducting electricity along the length of the pumping segment. In one embodiment, the pumping tube segment is fluidly connected to or is part of a drain line of a peristaltic dialysis system. In this case, the dialysate will sometimes flow through the pumping segment 130. In an embodiment, the pumping segment is fluidly connected in series with an exhaust line in the peritoneal dialysis system, thereby delivering spent dialysate from the patient (peritoneal cavity) to the exhaust system. The exhaust system may be at ground potential. This creates a risk of leakage current flowing through the dialysate and pumping segment 130 to ground.

The continuous blockage of the pumping segment 130 prevents current from flowing through the pumping segment 130. To reduce the chance of leakage current flowing through the drain line, pinch point 135 is maintained throughout to maintain a region of no conductive fluid in pumping segment 130. This is shown in fig. 1B.

Referring to fig. 1B, the central rotor 120 has rotated approximately 45 ° and it can be seen that in this case the pumping roller 102 remains pressed against the pumping tube segment 130 at the pinch point 135, while the pumping roller 103 is no longer in contact with the pumping tube segment 130. In this case, only a single pinch point 135 is created for at least a portion of the peristaltic pumping cycle. To ensure that no conductive fluid is present at pinch point 135, the spacing between central rotor 120 and shoe 125 may be adjusted so that the roller applies sufficient force to pumping segment 130 whenever the roller is in contact with the pumping segment. In addition, the pumping tube segment dimensions and material hardness, roller diameter and width, length and curvature of surface 145 are selected to ensure complete occlusion occurs at pinch point 135.

In some cases, it may be desirable to ensure that at least two pinch points 135 are always created due to degradation of the material of the pumping segment 130, wear of the rollers, and/or wear of the shoes. This is because there is a possibility that a single pinch point may not be sufficient to force all of the conductive fluid completely out of the pinch point, thus leaving a possibility that some current may pass through the pumping segment 130. Ensuring that there are always two pinch points reduces the likelihood of leakage current flowing through the pumping segment.

Turning to fig. 1C, a peristaltic pump 100 as shown in fig. 1B is shown. The angular spacing of the rollers is the same as that shown in fig. 1A. Further, the curvilinear length of surface 145 of boot 125 is represented by capital letter L. The length L is the length measured around the surface curvature. In addition, as shown by the greek letter α, the curved surface of the shoe 125 has a range of angles. It will be appreciated that there is a correlation between the angular range α and the length L. When the curved portion of the curved surface is a part of a circle, the length L may be determined as a part of the circumference of the circle. Even when the curved surface does not have a circular curvature, but is elliptical or some other ellipsoid, the angular range α is related to the angular distribution of the roller along the rotor 120. In an embodiment, the angular range α is large enough to ensure that both rollers are positioned radially against the curved surface at all times, such that two pinch points 135 are provided when the pumping tube segment is inserted into the space between the rotor 120 and the shoe 125. In an embodiment, when the angular spacing of the rollers is a degrees (fig. 1A), the angular range α is greater than or equal to 2×a degrees, which ensures that there will always be two pinch points 135 during 360 degrees of rotation of the rotor 120. Thus, when a small angular range α is desired (due to other design constraints), providing more rollers (and thus reducing a) may be used to ensure two pinch points 135. Conversely, when the number of rollers is constrained, the angular extent α of the shoe curved surface may be selected to ensure at least two pinch points 135.

In an embodiment, peristaltic pump 100 reduces or eliminates current flow in pumping tube segment 130 by coupling a rotor having a roller separated from an adjacent roller by an angle a with a pump shoe having an angular extent α greater than or equal to 2 x a degrees.

Referring to fig. 2A, an embodiment of a peristaltic pump 200 is shown that ensures that at least two pinch points (but possibly more) are always created. For greater clarity, the pumping segment 130 is omitted from fig. 2A, but it should be understood that the pumping segment 130 is installed in substantially the same manner as the pumping segment 130 of fig. 1A.

Peristaltic pump 200 includes a central rotor 220, the central rotor 220 having a plurality of rollers disposed about an outer circumference thereof. The plurality of rollers are grouped into roller sets. In one embodiment, as shown in FIG. 2A, there are four roller sets. Each of the four roller sets has two rollers. Rollers 201 and 202 are members of the first roller set; rollers 203 and 204 are members of the second roller set; rollers 205 and 206 are members of a third roller set; rollers 207 and 208 are members of the fourth roller set.

While four roller sets are shown in fig. 2A, it should be understood that there may be more or fewer roller sets and that there may be more than two rollers in each roller set. The specific number of sets of rollers and the specific number of rollers in each set is determined by the size of the rotor 220 and the length of the surface 145 of the shoe 125. In an embodiment, the number of roller sets, the number of rollers per roller set, and the length of surface 145 are selected such that there are two or more pinch points 135 all the way along pumping tube segment 130. When referring to the length of the surface 145 of the pump shoe 125, it is along the length L of the curved surface 145 that mates with the mentioned pumping tube segment.

As shown in fig. 2A, the spacing of all the rollers along the circumference of the rotor 220 is not uniform, but rather the rollers in the set of rollers are closer to the other rollers in the set. For example, in one embodiment, there are four roller sets, each separated from an adjacent roller set by 90 degrees (similar to the arrangement in fig. 1A). More specifically, the middle of each roller set is at 90 degrees to the middle of an adjacent roller set, even though the individual rollers in one set may be less than 90 degrees from the rollers in the other set.

In an embodiment, there are four roller sets on the rotor 220, and each roller set includes two rollers that are closer to each other than they are to the rollers in the other roller sets. In such an embodiment, at least 2 rollers included in one or more roller sets clamp the respective portions of the pumping tube segment 130 against the curved surface through a complete rotation of the rotor 220. In other embodiments, there are four roller sets, and each roller set includes three rollers. In further embodiments, there are three roller sets, and each roller set includes two rollers, three rollers, or four rollers.

When there are more than two pinch points 135 at all times, it can be ensured that no current can flow through the pumping segment 130 even if the conductive fluid is pumped through the pumping segment 130. In one embodiment, there are three rollers in each roller set, as shown in FIG. 2B.

Referring now to fig. 2B, peristaltic pump 290 is shown. Pump 290 includes a rotor 320 having a plurality of roller sets thereon. A roll set 321 is shown comprising individual rolls 301, 302 and 303. The pump shown in the embodiment of fig. 2B includes four roller sets, but there may be fewer or more roller sets. In one embodiment, rotor 320 includes four roller sets and each roller set includes three rollers. More specifically, rollers 304, 305, and 306 are members of one roller set; rollers 307, 308, and 309 are members of another roller set; and rollers 310, 311, and 312 are members of yet another set of rollers. Advantageously, this arrangement ensures that there are at least 3 points of contact (pinch points 135) on the pumping segment 130 (not shown in fig. 2B for clarity) at all times. For example, in the embodiment of fig. 2B, at least 3 rollers included in one or more roller sets clamp a respective portion of the pumping tube segment 130 against a curved surface through a complete rotation of the rotor 320.

Fig. 3A shows a peristaltic pump 300 comprising a rotor 120 with rollers 101, 102, 103 and 104. As shown, peristaltic pump 300 in the illustrated embodiment includes a modified boot 325. The modified shoe 325 has a curved surface 345 facing the rotor 120. Similar to the pump 100 of fig. 1A, the modified shoe 325 may be biased by a spring 116 along a biasing rod 114 or other urging mechanism. The curved surface 345 of the modified boot 325 includes a protrusion 335. The protrusion 335 is a portion of the curved surface 345 where the curvature is discontinuous and has the effect of creating a pressure spike as any roller rolls over the protrusion. By providing a protrusion such as 335 along the curved surface 345, occlusion of the tube 130 (not shown for greater clarity) is increased. By providing pressure spikes at specific locations, the likelihood of any conductive fluid remaining in the occluded portion of the tubing 130 is reduced, thus reducing the likelihood of leakage current flowing through the pumping segment 130.

As shown in fig. 3B, the pump shoe 326 may include more than one tab 335. In one embodiment, there are two protrusions 335 along curved surface 346. In other embodiments, there are three protrusions 335 (not shown) and they are spaced apart in equal distribution along curved surface 346. In embodiments, the rotor comprises three rollers, four rollers, five rollers, six rollers, seven rollers, or eight rollers. It should be appreciated that pump shoes 325 and 326 having one or more protrusions 335 may be used with any of the rotors described in this disclosure.

Fig. 4A shows one embodiment of a pump shoe 427 having a plunger 420 protruding through an opening 450 in a curved surface 447. The plunger 420 may be a curved plunger as shown mounted on a movable platform, such as a rod biased by a spring 416. In embodiments, the spring may be omitted or replaced with a hydraulically actuated plunger capable of moving the front tip or edge of the plunger 420 into and out of the surface 447. The view shown in fig. 4A may be considered a cross-sectional view of the top of the plunger 420 protruding through the opening 450 in the surface 447. The tip may have a conical cross section as shown. It is contemplated that the pump shoe 427 and all other pump shoes disclosed herein may be used with any of the pump rotors described in this disclosure. For example, the pump rotor 120 may be used with pump shoes 427. In one embodiment, the conical tip of the plunger 420 protrudes from the middle of the curved surface 447 of the pump shoe 427.

In other embodiments, as shown in fig. 4B, the plunger 420 is positioned not in the middle of the curved surface 448 of the shoe 428, but rather closer to one end of the surface. Opening 450 is not explicitly shown, but it should be understood that the plunger extends out of the opening much like in fig. 4A. This arrangement can increase pumping efficiency (volume per rotor revolution).

In still other embodiments, multiple plungers 420 may be used, as shown in fig. 4C. Two plungers 420 are positioned toward both ends of the curved surface 449 of the pump shoe 429. It should be appreciated that the plunger 420 creates increased pressure at the pinch point formed between the roller and the plunger, thereby reducing the likelihood that the conductive fluid will be retained at the pinch point inside the pumping segment 130. Thus, current cannot flow through the pumping segment 130.

Referring now to fig. 5, peristaltic pump 500 includes a central rotor 520 that is not necessarily circular in shape. In an embodiment, the central rotor may have a generally triangular shape or a star shape. The central rotor shape shown and described herein may be used with any other peristaltic pump described in this disclosure, and the term rotor need not necessarily have a circular shape. The rotor 520 has three rollers 501, 502 and 503. The rotor 520 is positioned against the pump shoe 525, the pump shoe 525 having a curved surface 545, the curved surface 545 having a length indicated by dashed line 546. The length of the curved surface 545 of the boot 525 is greater than the lengths of the other curved surfaces shown in the other figures. Thus, by extending the length of the curved surface of the pump shoe, the goal of ensuring that both rollers are always in contact with the pumping tube segment 130 (not shown in fig. 5 for greater clarity) can be maintained with fewer than four rollers on the rotor.

In an embodiment, a peristaltic pump includes a rotor having three rollers mounted on an outer circumference of the rotor and a pump shoe having a curved surface that presses against the rollers and the curved surface has a length sufficient to ensure that at least two rollers are in contact with the curved surface at all times during operation of the pump.

Fig. 6 illustrates a process for reducing or preventing leakage current in pumping segment 130 using a peristaltic pump according to any of the disclosed embodiments. In addition to or in lieu of the features described above that reduce or eliminate leakage current in the pumping segment, the peristaltic pump may be operated according to the process shown in fig. 6 to further reduce or eliminate leakage current. At S610, the pump rotor is rotated forward (in the normal direction) to cause fluid to be pumped through the pumping tube segment. A current sensor (not shown) is provided to detect the current flowing through the pumping segment 130 when the pump is running. If the current sensor detects a current above a predetermined threshold (such as 50 μA) at S620, the process continues at S630. On the other hand, if no current is detected, the pump rotor operates normally.

At S630, the peristaltic pump is controlled to block the flow of current. According to an embodiment, the peristaltic pump rotor continues to rotate forward until the two rollers come into contact with the pumping tube segment and press against the pump shoe, ensuring that there are two pinch points.

In other embodiments, when current is detected, the pump rotor reverses and rotates in the opposite direction until the rollers come to rest in a position that creates two pinch points.

In other embodiments, the peristaltic pump rotor stops and the pressure between the roller in contact with the pumping tube segment and the pump shoe increases. In an embodiment, the rotor may be rotated forward or backward until one roller stops at a position that maximizes the pressure on the pumping tube segment. For example, the position may be substantially horizontal in fig. 5 such that roller 502 will press into the middle of surface 545. In this case, if pump shoe 525 is mounted on a pressure biasing mechanism similar to that shown in FIG. 1A, the pressure from the mechanism acts directly on roller 502, thereby maximizing the pressure on the pumping segment at that location, and thus minimizing the likelihood of conductive fluid being present at that location of the pumping segment.

In an embodiment, such an increase in pressure may be achieved by increasing the spring tension of a biasing spring (e.g., spring 116 described above). In other embodiments, pressure may be increased with a pressure mechanism such as those described above that presses the rotor and/or pump shoe against each other with a pressure that is greater than the normal operating pressure. Thus, the pinch point maintained in this state is at a pressure greater than the normal operating pressure, thereby reducing the likelihood of fluid being present in the pumping segment at the pinch point.

In further embodiments, S630 includes stopping rotation of the rotor that was initially rotating in the forward direction, rotating the rotor in the reverse direction for a number of degrees of rotation (e.g., 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees), and then rotating again in the forward direction. The action squeezes out fluid that may be at the pinch point by a squeezing action without increasing the pressure at the pinch point. Of course, this operation may be combined with other disclosed embodiments. For example, the forward and backward oscillations of the rotor may be performed by a roller on one of the pump shoe protrusions 335 to further enhance the squeezing effect and squeeze fluid out of the pumping tube segment 130 at the pinch point.

Medical systems, such as those used for kidney replacement therapy, may include dialysis systems (hemodialysis, peritoneal dialysis, etc.). In such systems, it is desirable to eliminate or reduce the current flowing in the various fluid lines (hollow tubes carrying fluid, typically conductive fluid). Peristaltic pumps according to the disclosed embodiments reduce or eliminate such current. One general aspect includes a peristaltic pump that reduces current flow through a pumping segment, and may include: a center rotor mounted on a center rotation axis; a shoe having a curved surface facing the central rotor; a plurality of rollers mounted along the circumference of the central rotor; and a pumped pipe section positioned between the curved surface and the central rotor, wherein each roller of the plurality of rollers is a member of a roller set, each roller set may include at least two rollers, the rollers of a particular roller set being physically closer to each other than they are to the rollers of other roller sets; and at least two rollers clamp a portion of the pumping segment against the curved surface through a complete rotation of the central rotor.

Embodiments of the first aspect may include one or more of the following features. The physical position of the roller is determined by the center of the roller. Each roller set may include three rollers.

Another general aspect of the present disclosure includes a peristaltic pump that reduces current flow through a pumping tube segment and may include: a center rotor mounted on a center rotation axis; a shoe having a curved surface facing the central rotor and having a length of the curved surface measured along the curved surface in a circumferential direction; and a plurality of rollers mounted along the circumference of the central rotor, wherein a pumping tube is positioned between the central rotor and the shoe, pinch points on the pumping tube are defined between any roller bearing against the shoe radially away from the central axis of rotation, and during 360 degrees of rotation of the central rotor, the number of rollers and the length of the curved surface are such as to always provide at least two pinch points on the pumping tube segment.

Implementations of the aspect may include one or more of the following features. The at least two pinch points are three pinch points. The plurality of rollers are uniformly distributed around the circumference of the central rotor at an angular spacing of a degrees, the angular extent of the curved surface being greater than or equal to twice a.

Another general aspect includes a peristaltic pump that reduces current flow through a pumping segment, and may include: a center rotor mounted on a center rotation axis; a shoe having a curved surface facing the central rotor and having a length of the curved surface measured along the curved surface in a circumferential direction; and a plurality of rollers mounted along the circumference of the central rotor, wherein a pumping tube is positioned between the central rotor and the shoe, a pinch point on the pumping tube is defined between any roller bearing against the shoe radially away from the central axis of rotation, and the curved surface of the shoe may include one or more protrusions towards the central rotor such that the pressure on the pumping tube segment between the roller and the protrusions is greater than the pressure on the pumping tube segment at any other location.

Implementations of the aspect may include one or more of the following features. The curved surface may include two protrusions that increase the pressure on the pumping tube segment at two different locations. The peristaltic pump may include a biasing mechanism that applies a force to the shoe in a direction toward the central rotor. The biasing mechanism may include a spring disposed on the lever. The biasing mechanism may include a motor that receives a control signal that adjusts the force applied by the motor to the boot. The central rotor may be pivotally mounted on the axis of rotation and the biasing mechanism may apply a force on the axis of rotation in a direction toward the shoe to press the central rotor against the curved surface of the shoe. The one or more protrusions may include a movable plunger extending out of the curved surface of the boot. The peristaltic pump may include an opening in the curved surface through which the plunger extends out of the curved surface. The plunger may be urged toward the central rotor by a biasing mechanism. The biasing mechanism may comprise a passive spring. The biasing mechanism may include a motor that is controlled by an electrical signal and applies a force having a magnitude based on the electrical signal. The boot may include two plungers extending from the curved surface at two different locations.

Another general aspect includes a method of pumping a conductive fluid while reducing current flowing through the conductive fluid, the method may include: providing a fluid pump; pumping a conductive fluid with the fluid pump; detecting the presence of an electrical current in the conductive fluid during pumping; measuring the magnitude of the detected current; comparing the magnitude of the measured current with a predetermined threshold; and in response to the threshold being exceeded, improving pumping of the fluid pump to reduce current flow through the conductive fluid.

Implementations of the aspect may include one or more of the following features. The fluid pump may include a peristaltic pump having: a central rotor; a plurality of rollers attached to the central rotor; a pump shoe having a curved surface disposed adjacent the central rotor; and a pumping segment positioned between the central rotor and the curved surface. Pumping the electrically conductive fluid may include rotating the central rotor in a first direction. Improving pumping of the fluid pump may include stopping the fluid pump in a state where there are at least two rollers pressing against the pumping pipe section and the pumping pipe section against the pump shoe. Improving pumping of the fluid pump may include rotating the rotor forward or backward until the at least one roller is positioned directly against the projection on the curved surface of the pump shoe. Improving pumping of the fluid pump may include increasing the pressure between the roller and the pump shoe. Increasing the pressure may include using a biasing mechanism to increase a force on a central axis of the rotor in a direction toward the pump shoe. Increasing the pressure may include using a biasing mechanism to increase a force on the pump shoe in a direction toward a central axis of the rotor. Increasing the pressure may include increasing a force on the central axis of the rotor in a direction toward the pump shoe using a first biasing mechanism and increasing a force on the pump shoe in a direction toward the central axis of the rotor using a second biasing mechanism. The fluid pump may include a peristaltic pump having: a central rotor; a plurality of roller sets, each roller set comprising two or more rollers attached to the central rotor; a shoe having a curved surface disposed adjacent the central rotor; and a pumping tube segment positioned between the central rotor and the curved surface, wherein the rollers in the same set of rollers are physically closer to each other than to the rollers in the other sets of rollers, and wherein at least two rollers included in one or more sets of rollers clamp a respective portion of the pumping tube segment against the curved surface through a complete rotation of the central rotor.

According to a first further embodiment, there is provided a peristaltic pump for reducing current through a pumping tube segment, the peristaltic pump comprising: a center rotor mounted on a center rotation axis; a shoe having a curved surface facing the central rotor; a plurality of rollers mounted along the circumference of the central rotor; and a pumping segment positioned between the curved surface and the central rotor, wherein each roller of the plurality of rollers is a member of a roller set, each roller set comprising at least two rollers, the rollers of a particular roller set being physically closer to each other than to the rollers of the other roller sets, and at least two rollers clamping a portion of the pumping segment against the curved surface through a complete rotation of the central rotor.

According to a second further embodiment, there is provided the peristaltic pump of the first further embodiment or any other of the preceding embodiments, wherein the physical position of the roller is determined by the center of the roller. According to a third further embodiment, there is provided the peristaltic pump of the first further embodiment or any other of the preceding embodiments, wherein each roller set comprises three rollers.

According to a fourth further embodiment, there is provided a peristaltic pump for reducing current through a pumping segment, the peristaltic pump comprising: a center rotor mounted on a center rotation axis; a shoe having a curved surface facing the central rotor and having a length of the curved surface measured along the curved surface in a circumferential direction; and a plurality of rollers mounted along the circumference of the central rotor, wherein a pumping tube is positioned between the central rotor and the shoe, pinch points on the pumping tube are defined between any roller bearing against the shoe radially away from the central axis of rotation, and during 360 degrees of rotation of the central rotor, the number of rollers and the length of the curved surface are such as to always provide at least two pinch points on the pumping tube segment.

According to a fifth further embodiment, there is provided the peristaltic pump of the fourth further embodiment or any other of the preceding embodiments, wherein the at least two pinch points are three pinch points. According to a sixth further embodiment, there is provided the peristaltic pump of the fourth further embodiment or any other of the preceding embodiments, wherein the plurality of rollers are evenly distributed around the circumference of the central rotor at an angular spacing of a degrees, the angular extent of the curved surface being greater than or equal to twice a.

According to a seventh further embodiment, there is provided a peristaltic pump for reducing current through a pumping segment, the peristaltic pump comprising: a center rotor mounted on a center rotation axis; a shoe having a curved surface facing the central rotor and having a length of the curved surface measured along the curved surface in a circumferential direction; and a plurality of rollers mounted along the circumference of the central rotor, wherein a pumping tube is positioned between the central rotor and the shoe, a pinch point on the pumping tube is defined between any roller bearing against the shoe radially away from the central axis of rotation, and the curved surface of the shoe includes one or more protrusions toward the central rotor such that the pressure on the pumping tube segment between the roller and the protrusions is greater than the pressure on the pumping tube segment at any other location.

According to an eighth further embodiment, there is provided the peristaltic pump of the seventh further embodiment or any other of the preceding embodiments, wherein the curved surface comprises two protrusions increasing the pressure on the pumping tube segment at two different positions. According to a ninth further embodiment, there is provided the peristaltic pump of the seventh further embodiment or any other of the preceding embodiments, further comprising a biasing mechanism that applies a force to the shoe in a direction towards the central rotor. According to a tenth further embodiment, there is provided the peristaltic pump of the ninth further embodiment or any other of the preceding embodiments, wherein the biasing mechanism comprises a spring disposed on the rod. According to an eleventh further embodiment, there is provided the peristaltic pump of the ninth further embodiment or any other of the preceding embodiments, wherein the biasing mechanism comprises a motor receiving a control signal regulating a force applied by the motor to the shoe. According to a twelfth further embodiment, there is provided the peristaltic pump of the seventh further embodiment or any other of the preceding embodiments, wherein the central rotor is pivotally mounted on the axis of rotation and the biasing mechanism applies a force on the axis of rotation in a direction towards the shoe to press the central rotor against the curved surface of the shoe. According to a thirteenth additional embodiment, there is provided the peristaltic pump of the seventh additional embodiment or any other of the preceding embodiments, wherein the one or more protrusions comprise a movable plunger extending out of the curved surface of the boot. According to a thirteenth additional embodiment, there is provided the peristaltic pump of the thirteenth additional embodiment or any other of the preceding embodiments, further comprising: an opening in the curved surface through which the plunger extends out of the curved surface. According to a fifteenth further embodiment, there is provided the peristaltic pump of the thirteenth further embodiment or any other of the preceding embodiments, wherein the plunger is urged toward the central rotor by a biasing mechanism. According to a sixteenth further embodiment, there is provided the peristaltic pump of the fifteenth further embodiment or any other of the preceding embodiments, wherein the biasing mechanism comprises a passive spring. According to a seventeenth additional embodiment, there is provided the peristaltic pump of the thirteenth additional embodiment or any other of the preceding embodiments, wherein the biasing mechanism includes a motor controlled by an electrical signal and exerting a force having a magnitude based on the electrical signal. According to an eighteenth further embodiment, there is provided the peristaltic pump of the thirteenth further embodiment or any other of the preceding embodiments, wherein the boot comprises two plungers extending from the curved surface at two different positions.

According to a nineteenth further embodiment, there is provided a method of pumping a conductive fluid while reducing current flowing through the conductive fluid, the method comprising: providing a fluid pump; pumping a conductive fluid with the fluid pump; detecting the presence of an electrical current in the conductive fluid during pumping; measuring the magnitude of the detected current; comparing the magnitude of the measured current with a predetermined threshold; and in response to the threshold being exceeded, improving pumping of the fluid pump to reduce current flow through the conductive fluid.

According to a twenty-first further embodiment, there is provided the method of the twenty-first further embodiment, wherein the fluid pump comprises a peristaltic pump having: a central rotor; a plurality of rollers attached to the central rotor; a pump shoe having a curved surface disposed adjacent the central rotor; and a pumping segment positioned between the central rotor and the curved surface. According to a twenty-first further embodiment, there is provided the twenty-further embodiment or the method of any other of the preceding embodiments, wherein pumping the electrically conductive fluid comprises rotating the central rotor in a first direction. According to a twenty-second further embodiment, there is provided the method of the nineteenth further embodiment or any other preceding embodiment, wherein improving pumping of the fluid pump comprises stopping the fluid pump in a state in which there are at least two rollers pressing against the pumping tube segment and the pumping tube segment against the pump shoe. According to a twenty-third embodiment, there is provided the method of the nineteenth embodiment or any other preceding embodiment, wherein improving pumping of the fluid pump comprises rotating the rotor forward or backward until the at least one roller is positioned directly against a protrusion on a curved surface of the pump shoe. According to a twenty-fourth additional embodiment, there is provided the nineteenth additional embodiment or the method of any other of the preceding embodiments, wherein improving pumping of the fluid pump comprises increasing pressure between the roller and the pump shoe. According to a twenty-fifth additional embodiment, there is provided the method of the twenty-fourth additional embodiment or any other of the preceding embodiments, wherein increasing the pressure comprises using a biasing mechanism to increase a force on the central axis of the rotor in a direction towards the pump shoe. According to a twenty-sixth additional embodiment, there is provided the twenty-fourth additional embodiment or the method of any other of the preceding embodiments, wherein increasing the pressure comprises using a biasing mechanism to increase a force on the pump shoe in a direction towards a central axis of the rotor. According to a twenty-seventh additional embodiment, there is provided the method of the twenty-fourth additional embodiment or any other of the preceding embodiments, wherein increasing the pressure comprises increasing a force on the central axis of the rotor in a direction towards the pump shoe using a first biasing mechanism and increasing a force on the pump shoe in a direction towards the central axis of the rotor using a second biasing mechanism. According to a twenty-eighth additional embodiment, there is provided the method of the nineteenth additional embodiment or any other of the preceding embodiments, wherein improving pumping of the fluid pump comprises rotating the rotor forward and backward to squeeze fluid out of the contact pinch point. According to a twenty-ninth further embodiment, there is provided the method of the nineteenth further embodiment or any other preceding embodiment, wherein: the fluid pump includes a peristaltic pump having: a central rotor; a plurality of roller sets, each roller set comprising two or more rollers attached to the central rotor; a shoe having a curved surface disposed adjacent the central rotor; and a pumping segment positioned between the central rotor and the curved surface, the rollers in the same set of rollers being physically closer to each other than they are to the rollers in the other sets of rollers, at least two rollers included in one or more sets of rollers sandwiching respective portions of the pumping segment against the curved surface through a complete rotation of the central rotor.

Features of the disclosed embodiments can be combined, rearranged, omitted, etc., to create additional embodiments within the scope of the disclosed subject matter. Furthermore, certain features may sometimes be used to advantage without a corresponding use of the other features. It is therefore apparent that there has been provided in accordance with the present disclosure a fluid pump and method for pumping a fluid that reduces or eliminates the current flowing in the fluid pumped by the fluid pump. The present disclosure is capable of many alternatives, modifications, and variations. While specific embodiments have been shown and described in detail to illustrate the application of the principles of the present disclosure, it will be understood that the disclosed subject matter may be otherwise embodied without departing from such principles. Accordingly, the applicant intends to cover all such alternatives, modifications, equivalents and variations as fall within the spirit and scope of the present disclosure.

Claims

1. A peristaltic pump for reducing current flow through a pumping segment, comprising:

a center rotor mounted on a center rotation axis;

a shoe having a curved surface facing the central rotor;

a plurality of rollers mounted along the circumference of the central rotor; and

a pumping segment positioned between the curved surface and the central rotor, wherein,

Each of the plurality of rollers is a member of a roller set,

each roll set comprises at least two rolls,

the rollers in a particular set of rollers are physically closer to each other than to the rollers in the other sets of rollers, an

At least two rollers clamp a portion of the pumping segment against the curved surface through a complete rotation of the central rotor.

2. The peristaltic pump of claim 1 wherein the physical location of a roller is determined by the center of the roller.

3. Peristaltic pump according to claim 1, wherein,

each roll set comprises three rolls.

4. A peristaltic pump for reducing current flow through a pumping segment, comprising:

a center rotor mounted on a center rotation axis;

a shoe having a curved surface facing the central rotor and having a length of the curved surface measured along the curved surface in a circumferential direction; and

a plurality of rollers mounted along the circumference of the central rotor, wherein,

a pumping tube is positioned between the central rotor and the shoe,

the pinch point on the pumping tube is defined between any roller pressing against the shoe radially away from the central axis of rotation and the shoe, and

During 360 degrees of rotation of the central rotor, the number of rollers and the length of the curved surface are such that at least two pinch points are provided on the pumping tube segment at all times.

5. The peristaltic pump of claim 4 wherein,

the at least two pinch points are three pinch points.

6. The peristaltic pump of claim 4 wherein,

the plurality of rollers are uniformly distributed around the circumference of the central rotor at an angular spacing of A degrees, an

The angular extent of the curved surface is greater than or equal to twice a.

7. A peristaltic pump for reducing current flow through a pumping segment, comprising:

a center rotor mounted on a center rotation axis;

a pumping tube is positioned between the central rotor and the shoe,

the curved surface of the shoe comprises one or more protrusions towards the central rotor such that the pressure acting on the pumping pipe section between the roller and the protrusions is greater than the pressure acting on the pumping pipe section at any other location.

8. Peristaltic pump according to claim 7, wherein,

the curved surface includes two protrusions that increase the pressure on the pumping tube segment at two different locations.

9. The peristaltic pump of claim 7 wherein the peristaltic pump further comprises:

a biasing mechanism that applies a force to the shoe in a direction toward the central rotor.

10. Peristaltic pump according to claim 9, wherein,

the biasing mechanism includes a spring disposed on the lever.

11. Peristaltic pump according to claim 9, wherein,

the biasing mechanism includes a motor that receives a control signal that adjusts the force applied by the motor to the shoe.

12. Peristaltic pump according to claim 7, wherein,

the central rotor is pivotally mounted on the axis of rotation, and

the biasing mechanism applies a force on the axis of rotation in a direction toward the shoe to press the central rotor against the curved surface of the shoe.

13. Peristaltic pump according to claim 7, wherein,

the one or more protrusions include a movable plunger extending out of a curved surface of the boot.

14. The peristaltic pump of claim 13 wherein the peristaltic pump further comprises:

An opening in the curved surface through which the plunger extends out of the curved surface.

15. Peristaltic pump according to claim 13, wherein,

the plunger is urged toward the central rotor by a biasing mechanism.

16. Peristaltic pump according to claim 15, wherein,

the biasing mechanism includes a passive spring.

17. Peristaltic pump according to claim 15, wherein,

the biasing mechanism includes a motor controlled by an electrical signal and applying a force having a magnitude based on the electrical signal.

18. Peristaltic pump according to claim 13, wherein,

the boot includes two plungers extending from a curved surface at two different locations.

19. A method of pumping a conductive fluid while reducing current flowing through the conductive fluid, wherein the method comprises:

providing a fluid pump;

pumping the conductive fluid with the fluid pump;

detecting the presence of an electrical current in the conductive fluid during pumping;

measuring the magnitude of the detected current;

comparing the magnitude of the measured current with a predetermined threshold; and

in response to the threshold being exceeded, pumping of the fluid pump is improved to reduce current flow through the conductive fluid.

20. The method of claim 19, wherein the fluid pump comprises a peristaltic pump having: a central rotor; a plurality of rollers attached to the central rotor; a pump shoe having a curved surface disposed adjacent the central rotor; and a pumping segment positioned between the central rotor and the curved surface.

21. The method of claim 20, wherein,

pumping the conductive fluid includes rotating the central rotor in a first direction.

22. The method according to any one of claims 19-21, wherein,

improving pumping of the fluid pump includes stopping the fluid pump with at least two rollers pressing against the pumping tube segment and with the pumping tube segment against the pump shoe.

23. The method according to any one of claims 19-21, wherein,

improving pumping of the fluid pump includes rotating the rotor forward or backward until at least one roller is positioned directly against a projection on a curved surface of the pump shoe.

24. The method according to any one of claims 19-21, wherein,

improving pumping of the fluid pump includes increasing the pressure between the roller and the pump shoe.

25. The method of claim 24, wherein,

increasing the pressure includes using a biasing mechanism to increase a force on the central axis of the rotor in a direction toward the pump shoe.

26. The method of claim 24, wherein,

increasing the pressure includes using a biasing mechanism to increase a force on the pump shoe in a direction toward a central axis of the rotor.

27. The method of claim 24, wherein,

Increasing the pressure includes using a first biasing mechanism to increase a force on the central axis of the rotor in a direction toward the pump shoe and using a second biasing mechanism to increase a force on the pump shoe in a direction toward the central axis of the rotor.

28. The method according to any one of claims 19-21, wherein,

improving pumping of the fluid pump includes rotating the rotor forward and backward to squeeze fluid out of the contact pinch point.

29. The method of claim 19, wherein,

the fluid pump includes a peristaltic pump having: a central rotor; a plurality of roller sets, each roller set comprising two or more rollers attached to the central rotor; a shoe having a curved surface disposed adjacent the central rotor; and a pumping segment positioned between the central rotor and the curved surface,

the rollers in the same set being physically closer to each other than to the rollers in the other sets, an

At least two rollers included in one or more roller sets clamp respective portions of the pumped pipe section against the curved surface through a complete rotation of the central rotor.