A peristaltic pump

Abstract

A peristaltic pump, comprising: a housing having a fluid inlet and a fluid outlet, a hose located in the housing for guiding fluid from the fluid inlet to the fluid outlet, a bidirectional motor, a drive shaft operatively connected to the motor and configured to be rotated by the motor, and a rotor connected to the drive shaft. The rotor is switchable between a first and a second connected position relative to the drive shaft. When the drive shaft is rotated by the motor in a first direction, the rotor is or becomes positioned in said first connected position, causing the rotor to repeatedly provide pressure on the hose in a peristaltic pumping action as the drive shaft continues to rotate in the first direction. When the drive shaft is rotated by the motor in a second direction which is opposite to the first direction, the rotor is or becomes positioned relative to the drive shaft in said second connected position, in which rotor pressure on the hose is reduced or eliminated.

Description

[0001] A peristaltic pump

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a peristaltic pump. The present disclosure also relates to a pump system comprising such a peristaltic pump.

[0004] BACKGROUND ART

[0005] Peristaltic pumps are widely used in food, cosmetic, pharmaceutical and many other industries for pumping a fluid from one location to another. Some peristaltic pumps have a rotor to which rollers are attached to its external circumference. The rollers compress a flexible hose as they repeatedly rotate by the hose. The part of the hose under compression becomes closed, thereby forcing the fluid in the hose to move through the hose. In some implementations, it may be desirable to remove the pressure on the hose to enable cleaning inside the hose. To enable cleaning operations on the inside of the hose, the pumping action is temporarily interrupted and the pressure on the hose is removed to allow for free flow through the hose during the cleaning process. However, with existing solutions, the mechanisms involved are complex and consist of many parts, making them expensive and difficult to assemble / disassemble and to service. There is thus still room for improvement.

[0006] SUMMARY OF THE INVENTION

[0007] An object of the present disclosure is to present a peristaltic pump which overcomes the above mentioned drawback, in particular an object is to provide a peristaltic pump which is made of relatively few parts and which can easily be set in a mode which allows for cleaning the hose. These and other objects, which will become apparent in the following discussion, are achieved by a peristaltic pump as defined in the accompanying claim 1. Some non-limiting exemplary embodiments are presented in the dependent claims and herein below.

[0008] The general inventive concept is based on the realization by the inventor that by designing a rotor / drive shaft combination which can have two different connected positions, it is possible to conveniently switch between a first connected position in which the rotor can press the hose for operating the peristaltic pump in a pumping mode, and a second connected position in which the rotor is displaced to allow for a cleaning mode of the pump. In particular, the inventor has realized that by using a bidirectional motor, the two different connected positions may be made selectable based on the rotational direction of the motor. Thus, rotating the motor in one direction can set the pump in a pumping mode, whereas rotating the motor in the opposite direction can set the pump in a cleaning mode. This will be discussed in more details in the following.

[0009] According to a first aspect of this disclosure, there is provided a peristaltic pump, comprising:

[0010] - a housing having a fluid inlet and a fluid outlet,

[0011] - a hose located in the housing for guiding fluid from the fluid inlet to the fluid outlet,

[0012] - a bidirectional motor,

[0013] - a drive shaft operatively connected to the motor and configured to be rotated by the motor,

[0014] - a rotor connected to the drive shaft, wherein the rotor is switchable between a first and a second connected position relative to the drive shaft, wherein,

[0015] - when the drive shaft is rotated by the motor in a first direction, the rotor is or becomes positioned in said first connected position, causing the rotor to repeatedly provide pressure on the hose in a peristaltic pumping action as the drive shaft continues to rotate in the first direction, and

[0016] - when the drive shaft is rotated by the motor in a second direction which is opposite to the first direction, the rotor is or becomes positioned relative to the drive shaft in said second connected position, in which rotor pressure on the hose is reduced or eliminated.

[0017] Thus, by controlling the rotational direction of the motor it is possible to select whether the peristaltic pump should be set in its pumping mode or cleaning mode. When the motor rotates the drive shaft in a first direction, the rotor (if not already in the first connected position) will become positioned in the first connected position, and as the drive shaft continues to rotate in the first direction the rotor will also rotate in the first direction and therefore be allowed to put pressure repeatedly on the hose to achieve the peristaltic pumping pressure. The rotor will repeatedly follow a closed geometrical trajectory and may, for example, for each full lap of the closed trajectory press the hose along an arc of the closed trajectory. This is then repeated lap after lap, whereby this sweeping pressing action along the arc of the trajectory achieves the pumping action. Conversely, when the motor rotates the drive shaft in the opposite direction, i.e. in the second direction, the rotor (if not already in the second connected position) will become positioned in the second connected position. In this second position any pressure of the rotor on the hose is reduced or eliminated. Any pressure reduction should be designed such that a satisfactory cleaning can be achieved through the hose. The requirements may depend on the particular implementation and industry in which the pump is used. For example, it may, be desirable to avoid creases inside the hose or other geometrical deformations that, for a particular implementation, may be considered as undesirable when flushing with a cleaning fluid. Once the rotor has reached the second position, the motor may suitably be temporarily stopped during any cleaning action, and then be restarted to drive the drive shaft in the first direction when pumping action is again desired. However, it may also be conceivable to allow the motor to continue to rotate the drive shaft in the second direction for a while after the rotor has become connected in the second connected position. Also in such case, any rotor pressure on the hose, if not completely eliminated, is such that it is adequately reduced, to allow for an efficient cleaning action. For instance, upon continued rotation in the second direction, the trajectory of the rotor may suitably be located in a contactless manner with respect to the hose.

[0018] The rotor may suitably be a single rotor connected to the drive shaft. Hereby, the number of parts of the pump can be kept low, and still provide a good pumping action, with the additional benefit of allowing the pump to be set in a cleaning mode in a simple, yet elegant, manner, by switching the connected position between the rotor and the drive shaft.

[0019] The first and the second connected positions provide different relative orientations between the rotor and the drive shaft. For example, if the rotor is connected to the drive shaft in the first connected position, then any random point on the circumference of the rotor and any random point on the drive shaft, may be connected by drawing a first imaginary straight line in space. If the rotor is then connected to the drive shaft in the second connected position, then you would need to draw a second and differently oriented imaginary straight line in space to connect the same random points.

[0020] According to at least one exemplary embodiment, the drive shaft has an axis of rotation representing a first geometrical axis, wherein the drive shaft is configured to cause the rotor to rotate relative to the drive shaft around a second geometrical axis which is offset from the first geometrical axis. By providing such an offset between said first and second geometrical axes, different trajectories of the rotor may be achieved depending on the relative orientation between the rotor and the drive shaft, i.e. depending on the connection between the two components being the first or the second connected position. The second geometrical axis may suitably be the centre axis of the rotor. Thus, the centre axis of the rotor may be offset from the axis of rotation of the drive shaft. The second geometrical axis may, in at least some exemplary embodiments, extend in parallel with the first geometrical axis. This may provide improved control of the pump.

[0021] According to at least one exemplary embodiment,

[0022] - when the rotor is positioned in said second connected position relative to the drive shaft, and the motor rotates the drive shaft in the first direction, the drive shaft turns relative to the rotor about the second geometrical axis towards said first connected position, and - when the rotor is positioned in said first connected position relative to the drive shaft and the motor rotates the drive shaft in the second direction, the drive shaft turn relative to the rotor about the second geometrical axis towards said second connected position.

[0023] In other words, when switching position, an initial relative movement is allowed between the drive shaft and the rotor. Thus, when the motor reverses the direction of rotation for the drive shaft (compared to the previous direction of rotation), a simple switching from one of the connected positions to the other connected position can be achieved, by allowing an initial relative rotation between the drive shaft and the rotor. Once the new connected position has been reached, the drive shaft may bring along the rotor in the rotating motion of the drive shaft. Such initial relative movement could be achieved in various ways, including using a controllable clutch or coupling mechanism. However, a more simple, yet efficient, example will be discussed later in this disclosure.

[0024] According to at least one exemplary embodiment, the drive shaft comprises a main pin defining said second geometrical axis, wherein the rotor comprises a hole for receiving the main pin, wherein the hole is off-centre from a central geometrical axis of the rotor. By having the hole off-centre, the trajectory of the rotor will become different depending on if the rotor is in the first or second connected position relative to the drive shaft. Providing a main pin on the drive shaft and a receiving hole in the rotor is a simple and convenient way to allow a relative temporary rotation between the rotor and the drive shaft as a switching between the first and second connected position (or vice versa) is performed. Nevertheless, it would be conceivable to instead have a pin extending from the rotor into a receiving hole in the drive shaft. Thus, generally speaking, in at least some exemplary embodiments, one of the drive shaft and the rotor may comprise a main pin defining said second geometrical axis, wherein the other one of the drive shaft and the rotor may comprise a hole for receiving the main pin, wherein the hole or the main pin (whichever one is comprised in the rotor) is located off-centre from a central geometrical axis of the rotor.

[0025] According to at least one exemplary embodiment, the housing has a cylindrical inner wall along which the hose extends in the circumferential direction, wherein when the drive shaft rotates the in the first direction the rotor is or becomes located eccentrically with respect to the cylindrical inner wall, whereas when the drive shaft rotates in the second direction the rotor is or becomes located concentrically with respect to the cylindrical inner wall. By allowing a change between an eccentric and a concentric location relative to the cylindrical inner wall, a clear distinction can be made between a pumping mode and a cleaning mode. In the eccentric location, the rotor will be allowed to provide a repeating pumping pressure onto the hose, whereas in the concentric location, it will be more distanced form the hose such that no or very little pressure is provided by the rotor to the hose. According to at least one exemplary embodiment, one of the rotor and the drive shaft is provided with a guiding part, and wherein the other one of the rotor and the drive shaft is provided with a guided part, wherein the guiding part defines a path along which the guided part is movable to cause the rotor to be switched between said first and second connected position. By providing such a guiding motion between the rotor and the drive shaft an efficient and convenient switching back and forth between the first and second connected positions may be achieved.

[0026] According to at least one exemplary embodiment, the guiding part is in the form of a curved slot and the guided part is in the form of a blocking pin inserted in the curved slot, wherein said first connected position is reached when the blocking pin arrives at a first end of the curved slot and said second connected position is reached when the blocking pin arrives at a second end of the curved slot. By providing a pin which is movable with a slot, a distinct end position is definable, as the pin reaches the respective ends of the slot. A curvature of the slot allows for an efficient way to move the centre of the rotor, for example so that the rotor can be centralized with respect to the housing when the pump is in cleaning mode, and to be off- centre when the pump is in pumping mode. It should be understood that instead of a pin being guided by a curved slot, there may be other conceivable solutions for creating a curved guided path. For instance, in some exemplary embodiments, the guiding part may be in the form of a curved rail, and the guided part may include a bracket engaging the rail and being slidable along the rail. Thus, generally speaking, in at least some exemplary embodiments the guiding part forms a curved path which the guided part is configured to follow. The curved path may suitably form a C-shape.

[0027] According to at least one exemplary embodiment, the rotor is provided with the curved slot and the drive shaft is provided with the blocking pin. This may be advantageous from a manufacturing point of view. For example, since the rotor may normally have a larger diameter than the drive shaft, there may be more material available on the rotor in which to provide a curved slot. However, in principle, it would be conceivable in at least some exemplary embodiments to provide a curved slot in the drive shaft instead.

[0028] According to at least one exemplary embodiment, the rotor is caused to rotate when the blocking pin pushes either one of the first and second ends of the curved slot, wherein pushing of the first end causes the rotor to rotate so as to provide said peristaltic pumping action, whereas pushing of the second end causes the rotor to become distanced from the hose to allow the rotor to rotate freely from the hose. This is beneficial as the switching between the connected positions and the continued action can be done in one motion. For instance, assuming that the rotor is presently in the second connected position relative to the drive shaft and therefore the blocking pin is at said second end of the curved slot (i.e. the pump may be in a cleaning mode). Then it is determined that the pump should now be operated in the pumping mode. The motor will therefore turn the drive shaft in the first direction moving the blocking pin from the second end to first end of the curved slot. As the motor continues to turn the drive shaft, the blocking pin will start pushing the rotor at the first end of the curved slot, and thereby bring along the rotor in the rotary motion of the drive shaft. Since the rotor is now being pushed at the first end of the curved slot instead of at the second end, the relative location of the rotor within the housing has now been shifted so that the rotor is now closer to the hose and can provide the desired peristaltic pumping action.

[0029] According to at least one exemplary embodiment, the peristaltic pump further comprises a fixed sliding plate provided annularly around the drive shaft, wherein the rotor is spring-biased against the fixed sliding plate to provide friction between the rotor and the fixed sliding plate. Thus, the drive shaft can conveniently be turned relative to the rotor when switching from one of the connected positions to the other one. The rotor may be kept in substantially fixed orientation due to the friction between the rotor and the fixed sliding plate even though the drive shaft is turned to change to the other connected position. Thus, in the example of a pinslot guiding arrangement, the pin will be allowed to move in the slot while the rotor is maintained in position by the friction between the rotor and the fixed sliding plate.

[0030] According to at least one exemplary embodiment,

[0031] - when the rotor is in said first connected position and the drive shaft rotates in the first direction, the rotation of the drive shaft causes the rotor to slide rotatingly along the fixed sliding plate,

[0032] - when the rotor is in said first connected position and the drive shaft rotates in the second direction, the friction between the rotor and the fixed sliding plate enables the drive shaft to rotate relative to the rotor so that said second connected position is reached.

[0033] By allowing the driving force of the drive shaft to be larger than the frictional force between the rotor and the sliding plate, the rotor will overcome the friction and follow the rotation of the drive shaft. For instance, in the case of a pin-slot example, the pin will push the first end of the slot with a sufficient force to cause the rotor to slide along the sliding plate. Conversely, if the the drive shaft has arrived at the second end of the slot, and the drive shaft is continued to be rotated in the second direction, the rotor will overcome the friction force and be pushed to the second connected position relative to the drive shaft (which may for example be a cleaning mode of the pump). According to at least one exemplary embodiment, the motor is configured to receive control signals from a control unit, based on which the rotational direction of the motor is determined. The control unit may in some exemplary embodiments be manually operated, wherein an operator may determine when to set the pump in a pumping mode and when to set it in a cleaning mode. In some exemplary embodiments, the control unit may automatically switch between the different modes of the pump, e.g. based on a pre-program cycle, based on input from sensors, etc. The control unit may include one or more computer servers or other computerized arrangements. The control unit may include a microprocessor, microcontroller, programmable digital signal processor or another programmable device. The control unit may also, or instead, include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. Where it includes a programmable device such as the microprocessor, microcontroller or programmable digital signal processor mentioned above, the processor may further include computer executable code that controls operation of the programmable device.

[0034] According to a second aspect of the present disclosure, there is provided a pump system comprising a peristaltic pump according to the first aspect, including any exemplary embodiment thereof, and a control unit, wherein the control unit is configured to send control signals to the motor for controlling the rotational direction of the motor. The advantages of the pump system of the second aspect are largely analogous to the advantages of the peristaltic pump of the first aspect, including any exemplary embodiments thereof.

[0035] According to at least one exemplary embodiment of the pump system, the control unit is configured to repeatedly execute a work cycle for the peristaltic pump, the work cycle comprising:

[0036] - a pumping mode, in which the control unit controls the motor to rotate the drive shaft in the first direction so as to cause said peristaltic pumping action; and

[0037] - a cleaning mode, in which the control unit controls the motor to rotate the drive shaft in the second direction so as to distance the rotor from the hose to allow for a cleaning fluid flow through the hose.

[0038] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the unit, device, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the unit, device, component, means, step, etc., unless explicitly stated otherwise. Further features of, and advantages of, the present invention will become apparent when studying the appended claims and the following description. The skilled person realizes that different features of the present general inventive concept may be combined to create exemplary embodiments other than those described in the following, without departing from the scope of the present general inventive concept.

[0039] BRIEF DESCRIPTION OF THE DRAWINGS

[0040] FIG. 1 is an exploded view of a peristaltic pump according to at least one exemplary embodiment of this disclosure.

[0041] FIG. 2 is another exploded view of the peristaltic pump of FIG. 1.

[0042] FIG. 3 is a cross-sectional view of the peristaltic pump of FIGS. 1 and 2.

[0043] FIG. 4 illustrates the peristaltic pump when the rotor is in a first connected position relative to the drive shaft.

[0044] FIG. 5 corresponds to FIG. 4, however, in a partly cut-away view.

[0045] FIG. 6 illustrates the peristaltic pump when the rotor is in a second connected position relative to the drive shaft.

[0046] FIG. 7 is a very schematic representation of a pump system according to at least one exemplary embodiment of this disclosure.

[0047] FIGS. 8-10 correspond to the views of FIGS. 1-3, respectively, however, showing at least one other exemplary embodiment.

[0048] DETAILED DESCRIPTION

[0049] FIG. 1 and FIG. 2 each show a respective exploded view of a peristaltic pump 1 according to at least one exemplary embodiments of this disclosure, however, from different angles / perspectives. FIG. 3 is a cross-sectional view of the peristaltic pump 1 of FIGS. 1 and 2.

[0050] With reference to FIGS. 1-3, the peristaltic pump comprises a housing 2. The housing 2 has a fluid inlet 4 for receiving any fluid to be pumped, such as liquids, emulsions, suspensions, etc. The housing 2 also has a fluid outlet 6 from which the pump 1 expels the fluid.

[0051] The peristaltic pump 1 comprises a hose 8 located in the housing 2. The hose 8 is provided to guide fluid from the fluid inlet 4 to the fluid outlet 6. The fluid inlet 4 and the fluid outlet 6 are here illustrated as facing away from each other, in opposite directions. The hose 8 makes a 360° turn within the housing 2 as it extends from the fluid inlet 4, then along an inner cylindrical wall 10 of the housing 2, and then to the fluid outlet 6. Furthermore, in order to be able to make a full 360° turn, the hose 8 may make a slightly spiral path. Thus, the fluid inlet 4 and the fluid outlet 6 may suitably be provided in different parallel geometrical planes along a centre axis X of the housing 2.

[0052] The peristaltic pump 1 further comprises a bidirectional motor 12 and a drive shaft 14 which is operatively connected to the motor 12 and which is configured to be rotated by the motor 12. The drive shaft 14 may suitably be centred with respected to the cylindrical inner wall 10 of the housing 2, and the axis of rotation of the drive shaft 14 may thus suitably coincide with the centre axis X of the housing 2. The drive shaft 14 may include a motor engaging portion 16, which defines said axis of rotation X.

[0053] The peristaltic pump 1 further comprises a rotor 18 connected to the drive shaft 18. The rotor 18 may be in the form of a substantially cylindrical block. Although various different ways of connecting the rotor 18 to the drive shaft 14 are conceivable, in the present exemplary embodiment, the rotor 18 is connected to the drive shaft 14 by receiving two pins 20, 22 of the drive shaft 14, a main pin 20 and a blocking pin 22. As best seen in FIG. 3, the main pin 20 as well as the blocking pin 22 are slightly displaced from the axis of rotation X of the drive shaft 14. As best seen in FIG. 1 , the rotor 18 may comprise a hole 24 for receiving the main pin 20. The hole 24 is off-centre with respect to a central geometrical axis of the rotor 18. Thus, the rotor 18 has a decentralized hole 24 for receiving the main pin 20 of the drive shaft 14. The rotor 18 also comprises a curved slot 26 for receiving the blocking pin 22. The curved slot 26 has the function of a guiding part, and the blocking pin 22 has the function of a guided part. As best seen in FIG. 1 , the curved slot 26 has a first end 28 and a second end 30, which thus limit the motion of the blocking pin 22 within the curved slot 26. In FIG. 3, the blocking pin 22 is at the first end 28 of the curved slot 26. Although a pin-slot combination is illustrated in the drawing figures, it should be understood that in line with what has been discussed elsewhere in this disclosure, other guiding configurations are also conceivable. As can be understood from the drawings, the drive shaft 14 has a central body 32, from which the motor engaging portion 16 projects in one direction (towards the motor 12), and from which the main pin 20 and the blocking pin 22 extend in an opposite direction (away from the motor 12).

[0054] The peristaltic pump 1 further comprises a fixed sliding plate 34 provided annularly around the drive shaft 14. The rotor 18 is spring-biased against the fixed sliding plate 34 to provide friction between the rotor 18 and the fixed sliding plate 34. Any suitably spring 36 may be used (indicated in FIG. 1). In the illustrated example, the spring 36 is held in place by means of a washer 38 and a screw or bolt 40.

[0055] The operation of the peristaltic pump 1 will now be discussed. The peristaltic pump 1 may be set in a pumping mode and in a cleaning mode. In the pumping mode the rotor 18 is connected to the drive shaft 14 in a first connected position, which is illustrated in FIGS. 4 and 5. In the cleaning mode the rotor 18 is connected to the drive shaft 14 in a second connected position, which is illustrated in FIG. 6.

[0056] The rotor 18 is switchable between these two connected positions, by simply selecting a direction of rotation of the drive shaft 14. When the drive shaft 14 is rotated by the motor 12 in a first direction, the rotor 18 is or becomes positioned in said first connected position (FIG. 4). The first direction is illustrated by the double arrow in FIGS. 4 and 5. As can be seen in these two figures, the rotor 18 has become located eccentrically with respect to the cylindrical wall 10. When the drive shaft 14 is rotated by the motor 12 in a second direction (the second direction is illustrated by the double arrow in FIG. 6) which is opposite to the first direction, the rotor 18 is or becomes positioned relative to the drive shaft 14 in said second connected position (FIG. 6). As can be seen in FIG. 6, the rotor 18 may now become located concentrically with respect to the cylindrical inner wall 10.

[0057] As can be seen in FIGS. 4 and 5, when the rotor 18 is in said first connected position, it is positioned off-centre with respect to the cylindrical inner wall 10 of the housing 2. Therefore, when rotor 18 is rotated by the drive shaft 14, the rotor 18 will repeatedly provide pressure on the hose 8 in a peristaltic pumping action as the drive shaft 14 continues to rotate in the first direction. Thus, for each full rotation of the drive shaft 14 the rotor 18 will approach the hose 8 and pressingly pass along a portion of the hose 8 before it leaves the hose 8 and then returns to again approach the hose 8, etc. FIG. 3 shows similarly to FIGS. 4 and 5 how a lower portion of the hose 8 is currently in a compressed state due to the pressure provide by the rotor 18.

[0058] In the second connected position, however, the rotor 18 is positioned relative to the drive shaft 14 such that the pressure of the rotor 18 on the hose 8 is reduced or eliminated. For example, as illustrated in FIG. 6, the rotor 18 may in the second connected position be centred with respect to the cylindrical inner wall 10 of the housing 2, such that even though the drive shaft 14 keeps rotating the rotor 18 in the second direction, the rotor 18 will remain centred without touching or at least without any substantial effect on the hose 8. Thus, in this position, the hose 8 may suitably be cleaned by flushing any suitably cleaning medium through the hose 8, without the rotor disturbing the cleaning procedure. When the blocking pin 22 pushes the first end 28 of the curved slot 26, the rotor 18 is caused to rotated in the first direction (pumping mode). The rotation of the drive shaft 14 and it bringing along the rotor 18 in the first direction, causes the rotor 18 to slide rotatingly along the fixed sliding plate 34 (the pushing force of the blocking pin 22 overcomes the frictional force between the rotor 18 and the fixed sliding plate 34). Conversely, when the blocking pin 22 instead pushes the second end 30 of the curved slot 26, the rotor 18 is caused to rotate in the second direction (cleaning mode). Thus, when the motor 12 has rotated the drive shaft 14 in the first direction for operating the pump 1 in the pumping mode, and then switches to the second direction, the drive shaft 14 will initially rotate relative to the rotor 18 due to the friction between the rotor 18 and the fixed sliding plate 34. During that relative rotation, the blocking pin 22 will travel along the curved slot 26 from the first end 28 to the second end 30. When the blocking pin 22 comes into contact with the second end 30, the blocking pin 22 will push the rotor 18 and bring along the rotor 18 in the rotational motion of the drive shaft 14. The rotor 18 will thus become positioned in the second connected position (cleaning mode) shown in FIG. 6.

[0059] The selection of operating modes for the pump 1 may be achieved automatically or by manual input. Thus, switching between a pumping mode (e.g. FIG. 4) and a cleaning mode (FIG. 6) may be achieved by a person interacting with a user interface of the peristaltic pump 1 or a user interface of any control unit operatively connected to the peristaltic pump 1. In other examples, a control unit may be pre-programmed to switch between the different modes. This may be at pre-programmed time-intervals, or based on input from a sensor, or input from another processing device, etc. The control unit, regardless of it being manually or automatically controlled, may form part of a pump system, such as the schematically illustrated pump system 50 of FIG. 7.

[0060] FIG. 7 is a very schematic representation of a pump system 50 according to at least one exemplary embodiment of this disclosure. The pump system 50 comprises a peristaltic pump 1 of this disclosure, including any exemplary embodiment thereof. The pump system 50 also comprises a control unit 52. The control unit 52 is configured to send control signals 54 to the motor of the peristaltic pump 1 for controlling the rotational direction of the motor 12. In at least some exemplary embodiments, the control unit 52 may be configured to repeatedly execute a work cycle for the peristaltic pump 1. Such a work cycle may comprise a pumping mode and a cleaning mode. These two modes may thus be repeated one after the other to perform several work cycles. In the pumping mode, the control unit 52 controls the motor 12 to rotate the drive shaft 14 in the first direction so as to cause a peristaltic pumping action. In the cleaning mode, the control unit 52 controls the motor 12 to rotate the drive shaft 14 in the second direction so as to distance the rotor 18 from the hose 8 to allow for a cleaning fluid flow through the hose 8. FIGS. 8-10 correspond to the views of FIGS. 1-3, respectively, however, showing at least one other exemplary embodiment of a peristaltic pump 100. Similarly to the embodiment in FIGS. 1-3, the embodiment in FIGS. 8-10 has a guiding part in the form of a curved slot 126, and a guided part in the form of a blocking pin 122. However, the locations of these two components of the guide arrangement have been switched. In the embodiment of FIGS. 8-10 the curved slot 126 is provided in the drive shaft 114, whereas the blocking pin 122 extends from the rotor 118.

[0061] From the above, it can be understood that in a general sense, which is valid for both the embodiment of FIGS. 1-3 and the embodiment of FIGS. 8-10 (and also valid for other exemplary embodiments), one of the rotor 18, 118 and the drive shaft 14, 114 may be provided with a guiding part, and the other one of the rotor 18, 118 and the drive shaft 14, 114 may be provided with a guided part. In either case, the guiding part may define a path along which the guided part is movable to cause the rotor 18, 118 to be switched between the first and the second connected positions.

[0062] Turning back to the exemplary embodiment of FIGS. 1-3 (although the following is also applicable to the embodiment in FIGS 8-10, and to other exemplary embodiments as well), the axis of rotation X of the drive shaft 14 may be considered to represent a first geometrical axis. The drive shaft 14 is configured to cause the rotor 18 to rotate relative to the drive shaft 14 around a second geometrical axis which is offset from the first geometrical axis. That second geometrical axis is defined by the main pin 20. This offset between the first and the second geometrical axes allows for the rotor being selectively positioned eccentrically as in FIGS. 4 and 5, or concentrically as in FIG. 6. As can be seen in the embodiment of FIGS. 1-3, the motor engaging portion 16 of the drive shaft 14 and the main pin 20 extend along two separate geometrical axes. In particular, these two geometrical axes (first and second geometrical axes) may extend in parallel with each other. When the rotor 18 is positioned in the second connected position relative to the drive shaft 14 (such as in FIG. 6) and the motor 12 has been rotating the drive shaft 14 in the second direction (indicated by the dashed double arrow in FIG. 6), and then the motor 12 switches to rotate the drive shaft 14 in the first direction (indicated by the double arrow in FIGS. 4 and 5) the drive shaft 14 will turn relative to the rotor 18 about the second geometrical axis towards the first connected position (such as in FIGS. 4 and 5). Conversely, when the rotor 18 is positioned in the first connected position relative to the drive shaft 14 and the motor 12 rotates the drive shaft in the second direction, the drive shaft 14 turns relative to the rotor 18 about the second geometrical axis towards the second connected position.

Claims

CLAIMS1. A peristaltic pump, comprising:- a housing having a fluid inlet and a fluid outlet,- a hose located in the housing for guiding fluid from the fluid inlet to the fluid outlet,- a bidirectional motor,- a drive shaft operatively connected to the motor and configured to be rotated by the motor,- a rotor connected to the drive shaft, wherein the rotor is switchable between a first and a second connected position relative to the drive shaft, wherein,- when the drive shaft is rotated by the motor in a first direction, the rotor is or becomes positioned in said first connected position, causing the rotor to repeatedly provide pressure on the hose in a peristaltic pumping action as the drive shaft continues to rotate in the first direction, and- when the drive shaft is rotated by the motor in a second direction which is opposite to the first direction, the rotor is or becomes positioned relative to the drive shaft in said second connected position, in which rotor pressure on the hose is reduced or eliminated.

2. The peristaltic pump according to claim 1, wherein the drive shaft has an axis of rotation representing a first geometrical axis, wherein the drive shaft is configured to cause the rotor to rotate relative to the drive shaft around a second geometrical axis which is offset from the first geometrical axis.

3. The peristaltic pump according to claim 2, wherein- when the rotor is positioned in said second connected position relative to the drive shaft, and the motor rotates the drive shaft in the first direction, the drive shaft turns relative to the rotor about the second geometrical axis towards said first connected position, and- when the rotor is positioned in said first connected position relative to the drive shaft and the motor rotates the drive shaft in the second direction, the drive shaft turnrelative to the rotor about the second geometrical axis towards said second connected position.

4. The peristaltic pump according to any one of claims 2-3, wherein the second geometrical axis extends in parallel with the first geometrical axis.

5. The peristaltic pump according to any one of claims 2-4, wherein the drive shaft comprises a main pin defining said second geometrical axis, wherein the rotor comprises a hole for receiving the main pin, wherein the hole is off-centre from a central geometrical axis of the rotor.

6. The peristaltic pump according to any one of claims 1-5, wherein the housing has a cylindrical inner wall along which the hose extends in the circumferential direction, wherein when the drive shaft rotates the in the first direction the rotor is or becomes located eccentrically with respect to the cylindrical inner wall, whereas when the drive shaft rotates in the second direction the rotor is or becomes located concentrically with respect to the cylindrical inner wall.

7. The peristaltic pump according to any one of claims 1-6, wherein one of the rotor and the drive shaft is provided with a guiding part, and wherein the other one of the rotor and the drive shaft is provided with a guided part, wherein the guiding part defines a path along which the guided part is movable to cause the rotor to be switched between said first and second connected position.

8. The peristaltic pump according to claim 7, wherein the guiding part is in the form of a curved slot and the guided part is in the form of a blocking pin inserted in the curved slot, wherein said first connected position is reached when the blocking pin arrives at a first end of the curved slot and said second connected position is reached when the blocking pin arrives at a second end of the curved slot.

9. The peristaltic pump according to claim 8, wherein the rotor is provided with the curved slot and the drive shaft is provided with the blocking pin.

10. The peristaltic pump according to claim 9, wherein the rotor is caused to rotate when the blocking pin pushes either one of the first and second ends of the curved slot, wherein pushing of the first end causes the rotor to rotate so as to provide saidperistaltic pumping action, whereas pushing of the second end causes the rotor to become distanced from the hose to allow the rotor to rotate freely from the hose.

11. The peristaltic pump according to any one of claims 1-10, further comprising a fixed sliding plate provided annularly around the drive shaft, wherein the rotor is spring- biased against the fixed sliding plate to provide friction between the rotor and the fixed sliding plate.

12. The peristaltic pump according to claim 11, wherein- when the rotor is in said first connected position and the drive shaft rotates in the first direction, the rotation of the drive shaft causes the rotor to slide rotatingly along the fixed sliding plate,- when the rotor is in said first connected position and the drive shaft rotates in the second direction, the friction between the rotor and the fixed sliding plate enables the drive shaft to rotate relative to the rotor so that said second connected position is reached.

13. The peristaltic pump according to claim 12, wherein the motor is configured to receive control signals from a control unit, based on which the rotational direction of the motor is determined.

14. A pump system comprising a peristaltic pump according to any one of claims 1-13 and a control unit, wherein the control unit is configured to send control signals to the motor for controlling the rotational direction of the motor.

15. The pump system according to claim 14, wherein the control unit is configured to repeatedly execute a work cycle for the peristaltic pump, the work cycle comprising:- a pumping mode, in which the control unit controls the motor to rotate the drive shaft in the first direction so as to cause said peristaltic pumping action; and- a cleaning mode, in which the control unit controls the motor to rotate the drive shaft in the second direction so as to distance the rotor from the hose to allow for a cleaning fluid flow through the hose.

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