Patent Description:
The invention also relates to a method to switch the peristaltic pump from an operative configuration to a released configuration and vice versa.

Furthermore, the invention also relates to a method to balance fluid pressures in the fluid line, upstream and downstream the peristaltic pump of the present invention.

Peristaltic pumps are commonly used to promote fluid flow in a fluid line: in particular peristaltic pumps are used in medical field because of safety reasons as these pumps allow to prevent the fluid from contacting external parts other than the line, thereby improving sterilization.

In common peristaltic pumps, rollers or shoes compress the flexible line as they rotate, creating a negative pressure behind that recalls the fluid, and a positive pressure forward causing the fluid to advance. Common peristaltic pumps comprise a rotor carrying the rollers and a stator carrying a pump race partially surrounding the rotor and defining a gap in between: the flexible line is operatively arranged within this gap so that the line is compressed, in an operative condition, between a roller and the external pump race. Rotation of the rotor determines advancing of the roller with respect to the race over the line, causing the fluid in the line to advance.

During operations, it may be requested to periodically remove and reinstall the fluid line between the race and the rollers. Removal and reinstallation procedures imply to squeeze and forcibly manipulate the fluid line, as the latter is compressed or has to be compressed between the rollers and the surrounding race, thereby stressing repetitively the fluid line: manipulation may lead to premature damage of the fluid line causing the need of replacing it and negatively affecting the safety level of the pump system. Notably, a damage occurring to a blood line, such as a crack on the line, during an extracorporeal blood treatment, may lead to extremely dangerous consequences for the patient, such as massive blood loss or allowing bacteria to enter the blood stream.

Furthermore, as the fluid line is compressed between the rollers and the track, installation and removal procedures may result to be challenging, thereby requiring the intervention of a professional person, i.e. a nurse or a doctor, and extending the time required to accomplish the task.

SCOPE OF THE INVENTION <CIT> discloses a peristaltic pump in accordance with the preamble of claim <NUM>. The scope of this invention is therefore to at least partially solve one or more of the drawbacks and/or limitations of the prior art solutions.

A first scope is to provide a peristaltic pump able to substantially reduce or completely remove the risk of damaging the fluid line during periodical installation and removal procedures.

A further scope is to provide a peristaltic pump able to ease periodical installation and removal procedures of a fluid line without requiring massive manipulation.

A further scope is to provide a peristaltic pump combining manufacturing costs low and high reliability with the preceding features.

These scopes and more, which will appear more from the following description, are substantially achieved by a peristaltic pump in accordance with one or more of the following claims.

Some embodiments and some aspects of the invention will be described below with reference to the attached drawings, provided for illustrative purposes only, wherein:.

In this detailed description, corresponding parts illustrated in the various figures are indicated with the same numerical references. The figures may illustrate the invention by means of non-scale representations; therefore, parts and components illustrated in the figures relating to the object of the invention may relate exclusively to schematic representations.

The terms upstream and downstream refer to a direction or trajectory of advancement of a fluid configured to flow within the fluid line during standard usage of the peristaltic pump. In particular the fluid is configured to flow from an upstream tract to a downstream tract of the fluid line: the pump is interposed between the downstream and the upstream tract of the fluid line. The upstream tract is commonly known as the supply line, while the downstream tract is commonly known as the delivery line.

Reference number <NUM> is directed to a peristaltic pump as shown in <FIG>. The working principle of a peristaltic pump is well known to a skilled person: thus, the features described here after and associated to the main components of a common peristaltic pump have to be read as exemplary, as the skilled person is able to provide further modification non relating to the key concept of the present invention, which necessarily involves the presence of a releasing system <NUM> configured to ease installation and removal procedures of a fluid line.

The peristaltic pump of the present invention may be used for several purposes in a broad range of technical fields. In particular, the peristaltic pump of the present invention is directed to the medical field, in particular to dialysis field, wherein the fluid line may transport blood, dialysis fluid, replacement fluid, infusion fluid or the like. Normally, peristaltic pump in medical field are configured to provide a fluid rate for blood within a range between <NUM>/min and <NUM>/min, more in particular between <NUM>/min and <NUM>/min. Note that usually blood flow rate is paired with a dialysate flow of about double the blood flow rate (e.g. <NUM>/min to <NUM>/min - <NUM>/min to <NUM>/min).

Peristaltic pump <NUM> is configured to receive a fluid line <NUM> having a diameter comprised between <NUM> and <NUM>: the fluid line may be made by plastic or silicone material. The main components of the peristaltic pump <NUM> are the stator <NUM>, which defines the static body of the pump, and the rotor <NUM> which is rotatable about a rotor axis RA: the stator <NUM> carries the rotor <NUM>. An exemplary peristaltic pump <NUM> with a tube line installed is shown in <FIG>.

The stator <NUM> comprises a base wall 2a and a pump race <NUM> emerging in height from the base wall 2a, defining an internal volume <NUM>: in particular the pump race <NUM> emerges substantially normally with respect to the base wall 2a. The pump race <NUM> may have a height comprised between <NUM> and <NUM>. The base wall may have a substantially flat shape or slightly conic, while the pump race <NUM> may have a semicircular shape, i.e. "C" or "U" shape, concentric to the rotor axis RA defining an internal wall configured to receive in abutment the fluid line: the fluid line, when arranged in the stator <NUM>, defines a loop as in <FIG>. The internal wall of the pump race <NUM> defines an operative arc wherein the rotor <NUM> is configured to operatively cooperate with the fluid line to promote fluid flow within the fluid line. The internal volume <NUM> of the stator <NUM> is laterally confined by this internal wall of the pump race <NUM> and confined on the bottom by the base wall 2a of the stator <NUM>.

The pump race <NUM> also has a lateral aperture 3a, as shown in <FIG>, configured to allow an inlet tract of the fluid line <NUM> to enter in the inner volume of the pump, and an exit tract of the fluid line to exit the pump. The lateral aperture defines a non-operative arc wherein the fluid line does not cooperate with the rotor: The non-operative arc may have an angular dimension comprised between <NUM>° and <NUM>°, more in particular between <NUM>° and <NUM>°, more in particular between <NUM>° and <NUM>°.

The stator <NUM> also has a through aperture <NUM> defining an aperture axis AA coincident with the rotor axis RA: the through aperture <NUM> is configured to bear a rotor axle 10b of the rotor <NUM>, as shown in the exploded view of <FIG>.

The stator <NUM> may be made by plastic or metallic material.

The rotor <NUM> of the present peristaltic pump <NUM> is surrounded at least partially by the pump race <NUM> and configured to rotate about the rotor axis RA. The rotor <NUM> is arranged at least partially in the internal volume <NUM> of the stator and may include a rotor axle 10b, carried by the stator and arranged in the through aperture <NUM> of the stator, and a rotor plate 10a coupled or coupleable to the rotor axle. The rotor <NUM> includes at least one contrasting element <NUM>, carried by the rotor plate 10a, configured to abut against the fluid line <NUM> and also rotatable about the rotor axis RA. The at least one contrasting element <NUM> is movable towards and away with respect to the rotor axis RA and the pump race <NUM> between a released position shown in <FIG>, <FIG> and <FIG>, wherein the at least one contrasting element <NUM> is away from the pump race <NUM>, and an operative position shown in <FIG>, <FIG> wherein the at least one contrasting element <NUM> is approached to the pump race <NUM> and configured to abut against the fluid line <NUM>. Notably, in the released position, the contrasting element <NUM> is at a distance from the pump race <NUM> higher than a corresponding distance in the operative position. In particular the contrasting element <NUM>, when arranged in the released position, defines a distance with respect to the inner wall of the pump race <NUM> comprised between <NUM> and two times an external diameter of the fluid line, more in particular between one and <NUM> times an external diameter of the fluid line. More in detail, this distance is comprised between <NUM> and <NUM>. In other terms, a contrasting element <NUM>, when arranged in the released position, is configured to reduce or completely remove a compression force on the fluid line <NUM> when the latter is installed on the pump <NUM>.

On the other hand, the contrasting element <NUM>, when arranged in the operative position, defines a distance with respect to the inner wall of the pump race <NUM> comprised between <NUM> and <NUM>, in order to compress the fluid line <NUM> against the pump race.

In an embodiment, the peristaltic pump <NUM> comprises two or more contrasting elements <NUM>: in particular the contrasting elements <NUM> may be in a number comprised between two and ten, more in particular between two and six according to design requirements.

Each contrasting element <NUM> may include at least one roller or shoe <NUM> configured to contact and squeeze the fluid line <NUM> against the pump race <NUM>, as shown in <FIG> show an embodiment of the pump using rollers <NUM> in order to reduce tangential stresses on the fluid line.

Each contrasting element <NUM> comprises a lever arm <NUM> extending in length between a hinged end 13a and a free end 13b, wherein the hinged end 13a is hinged to the rotor plate 10a, and the free end 13b carries the roller or shoe <NUM>. The lever arm <NUM> is rotatable about the hinged end 13a about a hinge axis HA and with respect to the rotor plate 10a: a rotation of the lever arm <NUM> about the hinge axis HA determines the passage of the respective contrasting element <NUM> between the operative position and the released position and vice versa.

In an embodiment wherein the pump comprises two contrasting elements <NUM>, the two contrasting elements <NUM> are arranged diametrically opposite each other, namely defining a <NUM>° angle in between. In a further embodiment wherein the pump comprises three or more contrasting elements <NUM>, the contrasting elements <NUM> may be angularly spaced each other in a substantially evenly manner, in particular wherein the three or more contrasting elements are equally spaced each other.

The lever arm <NUM> has an extended body and may have an abutment protrusion <NUM> emerging from the extended body: the abutment protrusion <NUM> is interposed between the extended body and the base wall 2a of the stator <NUM>. The abutment protrusion <NUM> may emerge from the extended body of the lever arm <NUM> towards the base wall 2a of the stator <NUM>, so that the abutment protrusion <NUM> is the closest portion of the lever arm <NUM> to the base wall 2a of the stator <NUM>. In other terms, the abutment protrusion <NUM> reduces a distance between the lever arm <NUM> and the base wall 2a of the stator <NUM>: the distance between the abutment protrusion <NUM> and the base wall 2a may be comprised between <NUM>,<NUM> and <NUM> or more mm.

In an embodiment, only one contrasting element <NUM> of the two or more contrasting elements comprises the abutment protrusion <NUM> interposed between the extended body and the base wall 2a of the stator <NUM> and engageable by a releasing member <NUM> described here after. In a further embodiment, two contrasting elements <NUM> of the two or more contrasting elements comprise respective abutment protrusions <NUM> interposed between the extended body and the base wall 2a of the stator <NUM> and engageable by the releasing member <NUM>. In a still further embodiment, all the contrasting elements <NUM> of the two or three or more contrasting elements comprise respective abutment protrusions <NUM> interposed between the extended body and the base wall 2a of the stator <NUM> and engageable by the releasing member <NUM>.

The peristaltic pump further comprises a thrusting element <NUM> configured to act, at least when the contrasting elements are in the operative position, in thrust on the contrasting elements <NUM> in an outwardly direction, wherein the outwardly direction is directed towards the pump race <NUM> and away from the rotor axis RA. In the embodiment shown in the attached figures, the thrusting element <NUM> is configured to act in thrust on the contrasting elements <NUM> both when the contrasting elements are in the operative position and when the contrasting elements are in the released position.

As shown in the embodiment, the pump <NUM> may comprise one thrusting element <NUM> active on two or three or more contrasting elements simultaneously. Alternatively, the pump <NUM> may comprise one thrusting element <NUM> for each contrasting elements on which the thrusting element <NUM> is active.

The thrusting element <NUM> may comprise an elastic element <NUM>, i.e. a spring, a rubber-like element, a compressive spring or a traction spring, acting on the contrasting elements <NUM> as shown in <FIG>. In particular one elastic element <NUM> may be provided for each contrasting element. The elastic element <NUM> is configured to move the contrasting element <NUM> in the outwardly direction allowing, and in particular causing, movement of the contrasting elements <NUM> from the released position to the operative position. Notably the elastic element <NUM>, although it provides a thrust on the contrasting elements <NUM> directed towards the pump race causing the movement of the contrasting elements <NUM> from the released position to the operative position, also allows the movement of the contrasting elements <NUM> from the operative position to the released position.

Notably, the elastic element is configured to exert, when the pump <NUM> is in the operative configuration, a force on the contrasting elements <NUM> such that the latter is able to adequately compress, in particular deform, the fluid line <NUM> to promote fluid flow. Furthermore, the elastic element is also configured to deform itself to allow the at least one contrasting element <NUM> to move in the opposite direction, namely from the operative position to the released position.

The elastic element may be a compression spring: in this case the compression spring acts on the lever arm <NUM> at a thrusting seat <NUM>, wherein this thrusting seat <NUM> may be interposed between the hinged end 13a and the free end 13b of the lever arm <NUM>, defining a third class lever wherein the compression spring defines the applied force and the fluid line defines the resistance force applied on the free end 13b of the contrasting element <NUM> through a roller. In this third class lever, the thrusting seat <NUM> is positioned at a distance with respect to the hinge axis HA of the lever arm <NUM> lower than a corresponding distance between free end 13b carrying the roller <NUM> and the hinge axis HA.

Alternatively, the free end 13b carrying the roller <NUM> may be interposed between the hinged end 13a and the thrusting seat <NUM>, defining a second class lever wherein the compression spring defines the applied force and the fluid line defines the resistance force applied on the free end 13b of the contrasting element <NUM> through a roller. In this second class lever, the thrusting seat <NUM> is positioned at a distance with respect to the hinge axis HA of the lever arm <NUM> higher than a corresponding distance between free end 13b carrying the roller <NUM> and the hinge axis HA.

Alternatively, the elastic element may be a traction spring acting on a pulling portion of the lever arm <NUM>, so that the hinged end 13a is interposed between the pulling portion and the free end 13b carrying the roller, defining a first class lever.

Thus, according to an embodiment wherein the pump comprises the elastic element <NUM>, namely a spring or a rubber-like element, the elastic element is the member in charge of providing a thrusting force, through the contrasting elements <NUM>, on the fluid line <NUM>: this provides a flexible coupling between the rollers <NUM> and the fluid line, being the elastic element able to eventually compensate variations in the line thickness, stiffness or presence of impurities. Furthermore, the spring rate or the rubber-like element stiffness is set in order to be able to compress the fluid line <NUM> adequately and determine a fluid flow.

According to a further embodiment, the elastic element may be replaced by a thrusting cam <NUM> movable by rotation between a thrusting position and a non-thrusting position. In the thrusting position the thrusting cam <NUM> abuts against the contrasting elements <NUM> causing the contrasting elements <NUM> to move in the operative position, while in the non-thrusting position the thrusting cam <NUM> allows the contrasting element <NUM> to move in the released position. In addition, the thrusting cam <NUM>, when arranged in the thrusting position, prevents, in particular does not allow, the contrasting elements <NUM> to move from the operative position to the released position. Notably, in the operative configuration of the pump <NUM>, the thrusting cam <NUM> is arranged in the thrusting position, while in the released configuration the thrusting cam <NUM> is arranged in the non-thrusting position.

The peristaltic pump of the present invention also comprises a releasing system <NUM> comprising a releasing member <NUM> borne by the stator <NUM> and movable between an active position and a rest position with respect to the stator <NUM>. In particular the releasing member <NUM> is engaged to the stator <NUM> keeping at least one degree of freedom with respect to the stator <NUM> to shift between the active position and the rest position, i.e. rotation about an own axis or a translation movement. The releasing member <NUM> of the releasing system <NUM> is configured, upon movement from the rest position to the active position, to shift the contrasting elements or one of the contrasting elements from the operative position to the released position.

Notably, the releasing member <NUM> is coupled to the stator <NUM> and decoupled from the rotor <NUM>. This means that the releasing member <NUM> does not rotate with the rotor <NUM> about the rotor axis RA. According to a specific embodiment, the releasing member <NUM> has only one degree of freedom with respect to the stator <NUM>, namely either rotation or translation.

In particular, during a working condition of the peristaltic pump <NUM>, namely while the rotor <NUM> rotates about the rotor axis RA, the releasing member <NUM> is fixed with respect to the stator.

The released position of the contrasting element <NUM> makes installation and removal procedures of fluid line easier, as the fluid line is not compressed between the pump race <NUM> and the rollers <NUM>, and also safer, as the fluid line may be removed or installed without forcing it. Furthermore, during time periods wherein the fluid line <NUM> is installed and the peristaltic pump <NUM> is not working, the releasing system <NUM> allows to arrange the constraining element <NUM> in the released position in order not to stress or damage the fluid line at the contact point. In addition, as also described after in the present description, releasing the contrasting elements <NUM> allows to re-establish fluid pressure balance between a delivery tract of the fluid line and a supply tract of the fluid line: in other words, this allows to re-establish fluid pressure balance upstream and downstream the peristaltic pump <NUM>.

According to the present invention, the releasing member <NUM> is spatially shifted with respect to the rotor axis RA and borne by the stator <NUM>: in particular the releasing member <NUM> emerges in height from the base wall 2a of the stator between the rotor axis RA and the pump race <NUM> within the internal volume <NUM> of the stator <NUM>. This feature combination provides benefits to the releasing system of the pump, as the manufacturing process is easier and cheap, and because the releasing member <NUM> does not affect the rotation of the rotor during a standard working condition of the peristaltic pump. Indeed, in standard working condition, the releasing member <NUM> is completely decoupled from the rotor movement, thereby improving safety and reliability of the pump.

The peristaltic pump <NUM> is configurable at least in an operative configuration and a released configuration. In the operative configuration, the releasing member <NUM> is arranged in the rest position to allow the at least one contrasting element <NUM> to be arranged in the operative position, and the contrasting element <NUM> is thrusted by the thrusting element <NUM> in the outwardly direction towards the pump race <NUM>. On the contrary, in the released configuration, the releasing member <NUM> is arranged in the active position engaging the contrasting element <NUM> and moving the contrasting element <NUM> in the released position away from the pump race <NUM>. Thus, in the operative configuration, the contrasting elements <NUM> are able to compress the fluid line to cause fluid flow upon rotation of the rotor <NUM>, while in the released configuration the contrasting element <NUM> is moved away from the pump race, and thus from the fluid line, to allow removal or installation of the fluid line. Notably, in the operative configuration the rotor <NUM> is configured to rotate about the rotor axis RA to determine a fluid flow: on the contrary, in the released configuration, rotation of the rotor <NUM> is prevented, in particular the rotation of the rotor is blocked so that the contrasting elements <NUM> are fixed in position.

In an embodiment not shown in the attached figures, the releasing member <NUM> may be a translating member movable by translation, i.e. the releasing member may be a lever movable between the active and the rest position, wherein in the active position the lever abuts against one or more of the contrasting elements <NUM> to move the latter in the released position. The lever may be moved manually by an operator or automatically by an actuator, for example an electric actuator controlled by a control unit <NUM>.

In a further embodiment, the releasing member <NUM> is a releasing cam <NUM> rotatable about a cam axis CA: in <FIG> the lever arms <NUM>, the rotor plate 10a and the rollers <NUM> have been hidden to show in detail the releasing cam <NUM>.

The cam axis CA is spatially shifted with respect to the rotor axis RA: in particular the cam axis CA of the releasing cam <NUM> is fixed with respect to the stator <NUM> and the releasing cam <NUM> is configured to rotate about the cam axis relative to the stator <NUM>. The cam axis CA may be substantially parallel to the rotor axis RA. A distance between the cam axis CA and the rotor axis RA may be comprised between <NUM> and <NUM>. Anyhow, the distance between the cam axis CA and the rotor axis RA is lower than a distance between the rotor axis RA and the internal wall of the pump race.

Upon rotation of the releasing cam <NUM>, the pump <NUM> may be configured in the operative configuration or in the released configuration. In more detail, when the pump <NUM> is in the operative configuration, the releasing cam <NUM> is rotated in the rest position to allow the at least one contrasting element <NUM> to move in the operative position: the contrasting element <NUM> is thrusted by the thrusting element <NUM> in the outwardly direction. On the contrary, when the pump <NUM> is in the released configuration, the releasing cam <NUM> is rotated in the active position, wherein the releasing cam <NUM> engages the contrasting element <NUM> and moves the contrasting element <NUM> in the released position away from the pump race <NUM>.

The releasing cam <NUM> includes a bearing axle 32a rotatable about the cam axis CA, and a cam-shaped top element 32b fixed at an end of to the bearing axle 32a, as shown in <FIG> and <FIG>. The top element 32b and the bearing axle 32a define the releasing cam <NUM> as a single body. Furthermore, the base wall 2a of the stator <NUM> comprises a through hole <NUM> carrying the bearing axle 32a of the releasing cam <NUM> as shown in the exploded view of <FIG>.

The cam-shaped top element 32b of the releasing cam <NUM> emerges in height from said base wall 2a of the stator <NUM> (see <FIG>) into the internal volume <NUM> of the stator defining a cam-shaped lateral abutment wall 32c. This height may be comprised between <NUM> and <NUM>. The cam-shaped lateral abutment wall 32c defines the thickness of the cam-shaped top element 32b that emerges from to the base wall 2a of the stator, so that the cam-shaped top element 32b is able to cooperate with one or more of the contrasting elements <NUM>. In more detail, when the releasing cam <NUM> is in the active position, the cam-shaped lateral abutment wall 32c abuts against the at least one contrasting element <NUM> of the rotor <NUM>, in particular against the abutment portion <NUM> of the lever arm <NUM> of the at least one contrasting element <NUM>, to define the released configuration of the peristaltic pump. On the contrary, when the releasing cam <NUM> is in the rest position, the cam-shaped lateral abutment wall 32c allows the at least one contrasting element <NUM> to move in the operative position to define the operative configuration of the peristaltic pump.

The releasing member <NUM> is interposed between the rotor axis RA and the pump race <NUM> with respect to a radial direction normal to the rotor axis RA. In particular the releasing cam <NUM>, and more in particular the cam axis CA of the releasing cam <NUM>, is interposed between the rotor axis RA and the pump race <NUM> with respect to a radial direction normal to the rotor axis RA. In addition, the releasing member <NUM> may be closer to the pump race <NUM> than to the rotor axis RA.

According to an embodiment, when the peristaltic pump <NUM> comprises two contrasting elements <NUM>, the releasing member <NUM>, namely the releasing cam <NUM> or the lever, is configured to engage only one contrasting element at a time of the two or more contrasting elements <NUM>. In other words, the releasing member <NUM> is configured to act on one single contrasting element <NUM> at a time, in particular on the contrasting element <NUM> positioned in the operative arc of the stator <NUM>. The other contrasting element <NUM> is not engaged by the releasing member and positioned in the non-operative tract of the stator <NUM>, as the two contrasting elements are diametrically opposite each other.

Alternatively, the peristaltic pump <NUM> may comprise three or more contrasting elements <NUM>: in this case the releasing member <NUM> is configured to engage either one contrasting element at a time of the three contrasting elements <NUM>, or two contrasting elements at a time of the three contrasting elements <NUM>.

As a general rule, the releasing member <NUM> may be configured to act only on the contrasting elements <NUM> which are positioned in the operative arc of the stator <NUM>: indeed, the other contrasting element positioned in the non-operative arc of the stator does not cooperate with the fluid line, making a retraction of these contrasting elements not necessary. In other terms, given at least one first contrasting element positioned in the operative angular arch, this at least one first contrasting element is engageable by the releasing member <NUM>. On the contrary, given at least one second contrasting element positioned in the non-operative angular arch, the at least one second contrasting element is not engageable by the releasing member <NUM>. Thus, the releasing member <NUM>, when passing from the rest position to the active position, is configured to engage the at least one first contrasting element to move the latter in the released position: on the contrary, the releasing member <NUM>, when passing from the rest position to the active position, is configured not to engage the at least one second contrasting element.

In an embodiment according to the preceding description, when switching between the operative configuration and the released configuration, the rotor <NUM> is arranged in a predefined angular unlocking position: the predefined angular unlocking position is defined as a position wherein at least one of the contrasting elements <NUM> is engageable by the releasing member <NUM> to switch from the operative position to the released position and vice versa. More specifically, when the rotor is in the predefined angular unlocking position, only one contrasting element <NUM> between the two or more contrasting elements <NUM> is engageable by the releasing member <NUM>.

Notably, when the rotor is in the predefined angular unlocking position, the releasing member <NUM> is configured to engage all the contrasting elements <NUM> positioned in the operative arc to move them between the released position and the operative position, while the contrasting elements in the non-operative arc may be not engageable by the releasing member <NUM>.

In the predefined angular unlocking position, the cam-shaped lateral abutment wall 32c of the releasing cam <NUM> faces the abutment protrusion <NUM> of the lever arm <NUM> of one respective contrasting element <NUM>. In particular, the releasing cam <NUM>, when the rotor is in the predefined angular unlocking position, is interposed between the abutment protrusion <NUM> of the lever arm <NUM> and the pump race <NUM> with respect to a radial direction, in particular with respect to a direction normal to the rotor axis RA.

The peristaltic pump <NUM> may also comprise a drive motor, such as an electric motor, connected to the rotor <NUM> and configured to cause rotation of the rotor about the rotor axis RA and promote fluid flow within the fluid line <NUM>. Furthermore, a position sensor <NUM> may be provided and configured to emit a signal representative of an angular position of the rotor <NUM> with respect to the stator <NUM>. In particular the position sensor <NUM> of the rotor is a Hall sensor configured to detect the position of a roller or shoe <NUM> or a passage of a roller or shoe while the rotor <NUM> rotates.

In addition, an actuator, i.e. an electric actuator or motor, may be provided and connected to the releasing member <NUM> and configured to move the releasing member between the active position and the rest position. In particular, in case the releasing cam <NUM> is provided, the actuator is configured to rotate the releasing cam <NUM> between the active position and the rest position. Furthermore, a position sensor <NUM> may be provided and configured to emit a signal representative of the active position or the rest position of the releasing member <NUM>.

The peristaltic pump may comprise a control unit <NUM> connected to at least one between the drive member <NUM>, the position sensor <NUM> of the rotor <NUM>, the actuator of the releasing member <NUM> and the position sensor of the releasing member <NUM>.

When the control unit is connected at least to the drive member <NUM> and the position sensor <NUM> of the rotor <NUM>, the control unit <NUM> is configured to receive the signal emitted by the position sensor <NUM> of the rotor <NUM>, and to determine an angular position of the rotor with respect to the stator <NUM>.

Analogously, when the control unit is connected at least to the actuator of the releasing member <NUM> and the corresponding position sensor <NUM> of the releasing member <NUM>, the control unit <NUM> is configured to receive the signal emitted by the position sensor of the releasing member <NUM>, and selectively determine whether the releasing member is in the active position or in the rest position.

The control unit may be configured to switch the peristaltic pump <NUM> from the operative configuration to the released configuration by performing at least the following steps:.

and wherein the control unit <NUM> is configured to switch the peristaltic pump <NUM> from the released configuration to the operative configuration by performing at least the following steps:.

The control unit may be also configured to perform a substituting procedure to replace a fluid line <NUM> in the peristaltic pump <NUM> by switching the pump from the operative configuration to the released configuration, removing the old fluid line, installing a new fluid line, and subsequently switching the pump from the released configuration to the operative configuration. In particular the substituting procedure comprises at least the steps of:.

The control unit <NUM> may also be configured to perform a releasing procedure and an installing procedure, wherein the releasing procedure is configured to remove the fluid line from the peristaltic pump <NUM>, and the installing procedure is configured to install the fluid line in the peristaltic pump <NUM>. Combination of the releasing procedure with the installing procedure results in the substituting procedure.

The releasing procedure comprises at least the steps of:.

The setting procedure comprises at least the steps of:.

Notably, the step of arresting or rotating the rotor <NUM>, in the setting, releasing and/or substituting procedure, may comprise the step of commanding the drive motor <NUM> to position the rotor <NUM> at the predefined angular unlocking position.

As already mentioned in description, the peristaltic pump of the present invention may allow to balance fluid pressures downstream and upstream the peristaltic pump <NUM> or periodically lower a differential pressure between downstream and upstream sections of the fluid line with respect to the peristaltic pump <NUM>.

A contrasting element <NUM> in the operative position abuts against the fluid line at a contact point causing the fluid line to be compressed, thereby limiting or inhibiting fluid communication across the contact point between fluid located upstream the pump and fluid located downstream the pump. Shifting the contrasting element <NUM> from its operative position to released position allows the fluid line <NUM> to re-expand at contact point, causing the fluid located upstream the pump <NUM> to be in fluid communication with the fluid located downstream the pump <NUM>, thereby eventually rebalancing a differential pressure.

The control unit <NUM> is configured to perform a pressure balancing procedure to re-balance fluid pressures across the pump, wherein the pressure balancing procedure comprises switching the pump from the operative configuration to the released configuration. In particular the balancing procedure may comprise the steps of:.

Furthermore, the control unit <NUM> may be configured to:.

According to an embodiment, the balancing procedure is performed during an extracorporeal blood treatment, in particular wherein the fluid in the fluid line <NUM> is blood.

As already mentioned in the description, a prolonged compression of one roller <NUM> on the fluid line during a period of inactivity of the pump <NUM>, namely during a period wherein the rotor <NUM> does not rotate, may lead to damage the fluid line at the contact point with the roller. For example, a prolonged compression may lead to plastic deformation of the fluid line.

In order to avoid this issue, the pump <NUM> of the present invention allows to retract the roller during inactivity periods of the pump <NUM>, so that no compression or a reduced compression is applied on the fluid line by the roller. On this regard, the control unit <NUM> is configured to perform a inactivity procedure to prevent damage to the fluid line <NUM> during prolonged inactivity periods of the pump <NUM>. The inactivity procedure comprises switching the pump from the operative configuration to the released configuration. In particular the inactivity procedure comprises the steps of:.

During the prolonged inactivity periods of the pump <NUM>, the fluid line <NUM> is mounted on the pump <NUM> interposed between the contrasting elements <NUM> and the pump race <NUM>.

The inactivity procedure may be triggered by an operator through a user interface, such as a graphical user interface or a button, operatively connected to the control unit <NUM>. Alternatively, the control unit may be configured to:.

The threshold period may be received as input by a user by a user interface or may be a predefined value. The inactivity time period threshold may be comprised between <NUM> minutes and <NUM> hour, in particular between <NUM> minutes and <NUM> minutes.

The control unit may be also configured to perform safety procedures aimed to prevent damages to the pump and increase reliability of the pump. According to this aim, the control unit <NUM> may be configured to:.

The step of preventing rotation of the drive motor <NUM> may be performed by the control unit by preventing the drive motor <NUM> to be supplied by an electrical current.

As a general, a rotation of the rotor <NUM>, when the pump <NUM> is in the released configuration, is prevented, in particular blocked. On the other hand, when the pump <NUM> is in the operative configuration, a rotation of the rotor <NUM> is allowed.

The present disclosure is also directed to methods performed by the peristatic pump <NUM> according to the preceding description and to the attached claims.

A method <NUM>, shown in the flow chart of <FIG>, is provided to switch the peristaltic pump <NUM> from the operative configuration to the released configuration and vice versa. The method to switch the peristaltic pump <NUM> from the operative configuration to the released configuration comprises:.

The method to switch the peristaltic pump <NUM> from the released configuration to the operative configuration comprises at least:.

Notably, the step of switching the pump from the operative configuration to the released configuration causes balancing of fluid pressures across the pump, in particular wherein a fluid differential pressure between upstream and downstream tracts of the fluid line during an operative configuration is balanced. In particular the differential pressure is reduced or reset to zero when the pump is arranged in the released configuration as the fluid upstream the pump is in fluid communication with the fluid downstream the pump.

The method may also comprise an inactivity procedure to prevent damages to a fluid line <NUM> installed on the pump <NUM> during a prolonged period of inactivity of the pump <NUM>: the inactivity procedure comprises a step of switching the pump <NUM> from the operative configuration to the released configuration or keeping the pump in the released configuration. This allows to remove compression provided by the roller <NUM> on the fluid line when the contrasting element <NUM> is in the operative position, namely when the roller squeezes the fluid line.

Furthermore, the inactivity procedure may comprise:.

The inactivity time period threshold may be comprised between <NUM> minutes and <NUM> hour, in particular between <NUM> minutes and <NUM> minutes.

A method for removing a fluid line <NUM> in a peristaltic pump <NUM> may also be provided, wherein this method comprises a releasing procedure to switch the peristaltic pump <NUM> from the operative configuration to the released configuration, the releasing procedure comprising at least the following steps:.

A method for installing a fluid line <NUM> in a peristaltic pump <NUM> is provided, the setting procedure comprising at least the following steps:.

A method for replacing a flud line <NUM> is a peristaltic pump <NUM> may be also provided, wherein the method comprises a substituting procedure including the steps of:.

A method for preventing damage to a fluid line <NUM> during prolonged inactivity periods of a peristaltic pump <NUM> may be provided, wherein this method comprises an inactivity procedure including at least the steps of:.

wherein, during said prolonged inactivity periods of the pump <NUM>, the fluid line <NUM> is mounted on the pump <NUM>, in particular wherein the fluid line <NUM> is interposed between at least one of the contrasting element <NUM> and the pump race <NUM>.

A method for balancing fluid pressures across a peristaltic pump <NUM> may be also provide, wherein the method comprises a pressure balancing procedure including at least the steps of:.

Claim 1:
Peristaltic pump (<NUM>) configured to receive a fluid line (<NUM>), said peristaltic pump comprising:
- a stator (<NUM>) comprising a pump race (<NUM>);
- a rotor (<NUM>) surrounded at least partially by the pump race (<NUM>) and configured to rotate about a rotor axis (RA), said rotor (<NUM>) comprising:
o at least one contrasting element (<NUM>) configured to abut against the fluid line (<NUM>), the at least one contrasting element (<NUM>) being movable towards and away with respect to the rotor axis (RA) and the pump race (<NUM>) between:
▪ a released position wherein the at least one contrasting element (<NUM>) is away from the pump race (<NUM>), and
▪ an operative position wherein the at least one contrasting element (<NUM>) is approached to the pump race (<NUM>) and configured to abut against the fluid line (<NUM>), in the released position the at least one contrasting element (<NUM>) being at a distance from the pump race (<NUM>) higher than in the operative position,
o a thrusting element (<NUM>) configured to act, at least in the operative position, in thrust on said contrasting element (<NUM>) in an outwardly direction towards the pump race (<NUM>); and
- a releasing system (<NUM>) comprising a releasing member (<NUM>) movable between an active position and a rest position;
wherein the peristaltic pump (<NUM>) is configurable in at least:
- an operative configuration wherein the releasing member (<NUM>) is moved in the rest position to allow the at least one contrasting element (<NUM>) to move in the operative position, the contrasting element (<NUM>) being thrusted by the thrusting element (<NUM>) in the outwardly direction; and
- a released configuration wherein the releasing member (<NUM>) is moved in the active position, said releasing member (<NUM>) engaging the contrasting element (<NUM>) and moving the contrasting element (<NUM>) in the released position away from the pump race (<NUM>);
characterized in that the releasing member (<NUM>) is borne by the stator (<NUM>) and is spatially shifted with respect to the rotor axis (RA).