Peristaltic pump and blood treatment device

Abstract

The invention relates to a peristaltic pump and a device for blood treatment. The peristaltic pump comprises a lower pump pipe, the lower pump pipe is arranged between an inlet and an outlet, and a pressure roller is applied to the lower pump pipe; a stator provided with an internal chamber delimited by a respective wall against which the portion of the lower pump pipe is pressed; a pressure roller that cyclically moves along a trajectory; the means for motorizing the pressure roller element comprise a base or rotor which rotates about an axis and which is integral with the pressure roller in its own rotation, the pressure roller being free to rotate about its axis. The inner wall of the stator spreads along a conical surface, and the conical surface is provided with a first opening and an axis coinciding with the rotation axis of the rotor; the engagement surface of the pressure roller is a tapered surface different from and smaller than the opening; the axis of the shaft of the pressurizer does not coincide with the axis of rotation of the rotor, and the pressure roller is integral with the rotor but is inclined with respect to said axis.

Description

Technical Field

[0001] The invention relates to a peristaltic pump and a blood processing device.

[0002] As described more fully below, the peristaltic pump of the present invention is connected to a removable, preferably disposable kit (or assembly) that is an integral part of the pump and houses the lower pump tubing and any additional components for control and eventual disposal of the pumped liquid.

[0003] The invention is applicable in the medical field, in particular in the treatment of blood in extracorporeal circulation, in which the following aspects are of relevant importance: reduction of trauma (hemolysis), possibility of rapid circuit replacement, assurance of sterility, reduction of risks associated with possible human errors, and simplicity and safety of execution.

[0004] This will not prevent their use from being extended to other equally important areas such as food processing, pharmaceutical and chemical industries. Background Art

[0005] A common peristaltic pump is usually composed of an outer cylindrical stator and an inner cylindrical rotor coaxial with the stator. The rotor usually includes two or more slideways or rollers and is driven by a motor connected thereto.

[0006] The motor rotates the internal rotor, which drives the rollers (or slides) in circular motion, which define a cylindrical track. A section of tube or "down-pump tube" (in fact, this is the technical term for the elastic tube section that is subject to the peristaltic action of the pump) is manually placed in the space between the inner surface of the stator, which serves as a reaction plane, and the circumferential surface defined by the pressure elements (slides or rollers) that rotate integrally with the rotor and are arranged along the outer surface of the rotor.

[0007] In a peristaltic pump of known type, the space for accommodating the lower pump tube is designed to be equal to the sum of the wall thicknesses of the tube to be compressed (depending on the type of fluid or tube to be pumped, more or less small variations can be chosen). The rollers compress the tube by gradually pressing it against the stator during the rotational movement of the rollers. By changing the internal volume of the compressed tube, the compressed tube generates a flow. In the tube section arranged upstream of the compression performed by the rotor (i.e. on the part that has been affected by the compression of the pressure roller), the tube regains its original shape due to its elastic memory by sucking in the pumped fluid. The cyclic, unidirectional repetition of this action enables pumping.

[0008] Peristaltic pumps of known type are not always able to offer the high quality standards mentioned above, i.e. with regard to reduction of trauma, possibility of rapid circuit replacement, reduction of manual intervention for replacing the lower pump tubing, guarantee of sterility, reduction of risks associated with possible human errors, and simplicity and safety of implementation.

[0009] WO / 2018 / 146541 provides a preliminary solution to the problems of the known technology, which document relates to a type of pump comprising a stator and a single pressurizer element, wherein the stator supports a tube portion for the pumped fluid to flow through, and the pressurizer element is capable of exerting pressure on the tube to cause cyclic contraction of the tube to facilitate movement of the fluid within the tube.

[0010] The pump described in WO / 2018 / 146541 is provided with a single pressurizer element equipped with a motorized device for rotating about its axis, the motorized device being designed to cause the pressurizer to follow a circular trajectory when in contact with the tube, thereby causing varying degrees of tube damage along the trajectory followed by the pressurizer element. Summary of the invention

[0011] The present invention aims to further improve the characteristics of pumps for medical use, generally for processing blood, and in a specific application case for pumping venous blood drawn from a tube through components suitable for CO2 removal, including an oxygenator, by defining the device covered by the invention.

[0012] Advantageously, the pump that is the subject of the present application is incorporated into an apparatus that also comprises other components such as a pressure gauge for controlling the (suction, prefilter and return) pressures, a safety shut-off device (or "clamp") for intervention in the event of an alarm, a bubble sensor and an oxygenator (or other component that performs the necessary functions for the desired treatment).

[0013] Therefore, one of the objects of the present invention is to provide very high standards of processing safety (i.e. in relation to the patient and operator involved) and essentially no damage (hemolysis) to the treated blood caused by the action of the single frustoconical pressurizer and the structural and functional characteristics of the pump and device in question.

[0014] In addition to the advantages associated with the substantial absence of blood damage, among the additional advantages of the present invention, there may be cited the remarkable simplicity of assembly of its constituent parts (i.e., the removable disposable holder containing the lower pump tube is assembled by connecting it directly to the pressurizer, without the need for auxiliary mechanisms for translational movements for correct positioning).

[0015] This results in greater simplicity and safety of use; moreover, even at a structural level, the realization of the pump is simplified thanks to the innovative construction of the rotor and stator (truncated cone), which brings advantages related to the characteristics of the special flow generated by the truncated cone pressurizer on the lower pump tube, which is arranged on a spiral path with variable diameter.

[0016] This flow is particularly suitable for reducing hemolysis caused by shear stress (shear stress).Another advantage relates to the possibility of a reduction in the number of moulds for moulding the stator and a corresponding simplification of the design and a reduction in costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The advantages and features of the invention will become more apparent from the following description made with reference to the accompanying drawings, provided by way of example and not limitation, in which:

[0018] Figure 1 is a schematic perspective view of an example of an embodiment of a device formed by a pump of the invention associated with a device for removing CO 2 from the blood mounted on a removable kit containing a stator and with accessory elements.

[0019] Figure 2 yes Figure 1 Top view of the example shown.

[0020] Figure 3 is based on a plane parallel to the plane presented by the upper device Figure 1 Top view of the example shown.

[0021] Figure 4 yes Figure 1 A perspective schematic diagram of the example shown, in which portions of the support stator, lower pump tube and other components of the removable and preferably disposable assembly have been removed.

[0022] Figure 5 , Figure 6 and Figure 7 It is used to support the stator, the lower pump tube and other preferably disposable component parts. Figure 5 It is a three-dimensional picture. Figure 6 It is a top view. Figure 7 It is a bottom view.

[0023] Figure 8 and Fig. 9 are side and top views, respectively, showing possible examples of how the lower pump tube may be arranged inside the stator;

[0024] Fig.10 is along Figure 3 Cross-sectional view of line XX.

[0025] Fig.11 and Fig.12 Are of different proportions Fig.10 A magnified detail of

[0026] Fig.13 is a schematic diagram of the arrangement of the pressurizer and the stator of the pump of the invention, particularly with regard to the dimensions and positioning of the two elements. DETAILED DESCRIPTION

[0027] In this specification, the following definitions will be used to identify components.

[0028] The term "lower pump tube" refers to a portion of the tube or tube section passing through the pump, on which a thrust suitable for determining its movement is exerted.

[0029] "Presser" refers to an element that is in direct contact with the lower pump tube (having a truncated structure in the present solution), which is placed and constructed to compress the lower pump tube to generate blood flow in the lower pump tube, and may also be referred to as a pressurizing element or pressurizer element.

[0030] "Rotor" refers to a rotating base supporting a shaft, the shaft being inclined relative to the axis of the rotor itself, about which the pressurizer rotates, and which causes the pressurizer to define a truncated orbit as the rotor rotates about its own vertical axis.

[0031] "Stator" refers to an element having a conical chamber, which is appropriately connected to the pressurizer to form a pump and forms an integral part of the pump by providing a reaction surface against which the pressurizer compresses the lower pump tube to generate blood flow according to the peristaltic principle.

[0032] "stator base" is a support integral with the stator, which allows its correct alignment with the pump and its accessories (in a preferred implementation, this assembly consisting of stator and stator base is made of injection moulding of a rigid transparent plastic material (e.g. polycarbonate or rigid polyvinyl chloride), to which the necessary tubing for connecting components and the patient is correctly connected; for uses other than medical, it is contemplated that it may be implemented in reusable materials);

[0033] The "Pump Base" is the flat surface to which the pump is attached, and contains the elements that properly align the stator base with the pump. These elements, "Stator Base", "Stator" and "Lower Pump Tube" are parts of a removable and preferably disposable assembly to which the oxygenator and tubing (which in turn connects to the catheter and patient) are attached.

[0034] Referring to the accompanying drawings, the peristaltic pump 100 of the embodiment of the present invention includes a stator 1, which supports a lower pump tube or tube portion 2 (also referred to as a portion of a tube, a lower tube pump or a lower pump), the lower pump tube 2 is used to flow through the pumped fluid; a pressurizer 3 (also referred to as a pressurizing element), the pressurizer 3 is suitable for applying pressure on the lower pump tube 2 to cause the lower pump tube 2 to cyclically contract, for moving the fluid therein; and a base 8 (also referred to as a pump base), the base 8 supports the pump, the base 8 is provided with locking components 20A, 20B, and the locking components 20A, 20B are used to limit the body indicated by the reference numeral 6 and integrated with its own base. Specifically, the main components of the peristaltic pump 100 include: a base unit 101 and a stator unit 102. As mentioned above, when the use of the pump is preferably, for example, as a blood treatment device, the stator unit 102 can be advantageously disposable.

[0035] In the non-limiting example shown in the figures, the blood treatment apparatus or blood treatment device 200 comprises a peristaltic pump 100 and an oxygenator 103 of disposable type associated with a stator unit 102. In other possible embodiments of the present invention, the blood treatment apparatus 200 may comprise a peristaltic pump 100 and other devices than an oxygenator.

[0036] In the preferred embodiment shown in the drawings, the two components 101 and 102 are joined by forming a recess which stabilizes the two components, as described below.

[0037] The stator 1 comprises a hollow body defining therein a substantially frustoconical chamber and provided with an internal groove 17 extending at least 360° and accommodating the lower pump tube 2 to keep it properly positioned and exposed inside the stator 1 itself.

[0038] Specifically, in the configuration shown in the drawings but not limited to the drawings, the inner truncated conical chamber of the stator 1 comprises a conical surface having an opening A1 equal to 60° in cross section. An inner groove 17 for accommodating the lower pump tube 2 is formed on the conical surface.

[0039] The pressurizer 3 of the peristaltic pump 100 has a substantially frustoconical configuration and, in the non-limiting configuration shown in the attached drawings, has an opening A3 equal to 45°. The pressurizer 3 is mounted on a shaft 30, via a bearing 31, which, in the example shown, is inclined by 7.5° relative to the axis of rotation of the rotor 90, so as to obtain the correct direction of the force compressing the lower pump tube 2, said force being perpendicular to the surface of the pressurizer 3 and to the stator 1 at the point of contact with the lower pump tube 2. This perpendicularity ensures that the position of the lower pump tube is properly maintained inside the stator, by eliminating the component of force that tends to dislocate the lower pump tube 2, jeopardizing normal operation.

[0040] Specifically, the inclination angle of the shaft 30A of the pressurizer 3 relative to the rotation axis 90 of the rotor 9 is equal to half of the difference between the opening angle of the truncated cone defined by the stator and the opening angle of the truncated cone defining the pressurizer; in the example shown, the inclination angle is equal to half of the difference between the value of A1 and the value of A3, that is, (60°-45°) / 2=7.5°.

[0041] In other words, the conical surface defining the pressurizer 3 is that of a right cone whose vertex A belongs simultaneously to the axis 90 of the truncated cone inside the stator, to the axis 90 of the rotor and to the axis 30A of the truncated cone of the pressurizer itself. Thus, the ratio between the diameters of any section obtained from the truncated cone of the pressurizer and from the truncated cone of the stator, perpendicular to its own axis, is constant when both sections pass through the same point of contact between the pressurizer and the stator.

[0042] In this way, at each contact point, the linear velocity of the rolling of the pressurizer on the compression surface of the lower pump tube 2 will always be the same, thereby avoiding an axial component that would cause the lower pump tube 2 to disengage from its correct position.

[0043] Fig.13 The “geometry” of the pump in question is described, showing the axis 90 of the stator 1 and the rotor 9 , the axis 30A of the pressurizer 3 and the point A defined by the intersection of the axes 90 , 30A and the extension of the apex of the truncated cone defining the pressurizer 3 and the stator 1 .

[0044] In other words, Fig.13 , the apex of the cones describing the stator and the pressurizer starts from the same point A, which is at the same time the origin of the respective axes 90, 30A. In the above configuration, the stator 1 and the pressurizer 3 are represented by respective sections perpendicular to their respective axes; reference numeral B corresponds to the small base of the stator 1, reference numeral C corresponds to the small base of the pressurizer 3, reference numeral D corresponds to the large base of the stator 1, reference numeral E corresponds to the large base of the pressurizer 3, and reference numerals P1 and P2 represent the two points of engagement between the pressurizer 3 and the stator 1.

[0045] By experiment, it is possible to demonstrate that, for any mutual positioning between the pressurizer 3 and the stator 1 along the track defined by the pressurizer 3, the following relationship exists:

[0046] B:C=D:E

[0047] In fact, the above relationship is valid at any junction along the track.

[0048] The pressurizer 3 is an idler and is drawn into the track of the pressurizer 3 defining the frustoconical surface by the rotation of the rotor 9 , which is connected to the drive 106 of the peristaltic pump 100 , as described below.

[0049] According to the present invention, the peristaltic pump 100 therefore comprises the following components in its most general configuration:

[0050] a tube section or lower pump tube 2 between the inlet 22 and the outlet 23, for passing the fluid to be pumped and exerting a pressure on the tube section or lower pump tube 2 suitable for generating a direct flow of the fluid from the inlet to the outlet;

[0051] - a stator 1 provided with an internal chamber defined by respective inner walls 17 against which the tube portion 2 is pressed;

[0052] - means 17 for holding the tube section 2 in the correct position relative to the stator 1, the means 17 for holding the tube section 2 in the correct position being constituted by the inner wall 17 of the stator 1 housing the tube section 2;

[0053] - a pressurizer 3 which moves cyclically along a trajectory in order to join the tube section or the lower pump tube 2 by exerting pressure on the tube section or the lower pump tube 2 via corresponding joining surfaces.

[0054] - Motorized means of the pressurizer (pressurizer element) 3, comprising a motorized base or rotor 9, which rotates about an axis 90 and is integral with the pressurizer 3 in rotation, the pressurizer rotating freely about its axis 30A relative to the motorized base or rotor 9.

[0055] Advantageously, the peristaltic pump 100 is characterized by:

[0056] The inner wall 17 of the stator 1 develops along a conical surface having a first opening A1 and an axis coinciding with the axis of rotation 90 of the rotor 9, the inner wall 17 forming an internal recess for receiving the tube portion 2;

[0057] - the engagement surface of the pressurizer 3 is a tapered opening surface A3 which is different from and smaller than the opening A1;

[0058] The pressurizer 3 is supported by a shaft 30 having the same axis 30A as the pressurizer 3 , the axis 30A not coinciding with the axis of rotation 90 of the shaft and of the rotor 9 integral therewith, but nevertheless passing through the point A.

[0059] The angle of inclination of the axis 30A relative to 90° is equal to half the difference between the angle A1 of the opening of the inner cone of the stator and the angle A3 of the opening of the cone of the pressurizer.

[0060] As shown in the figure, the pressurizer 3 is preferably provided with a cylindrical appendage 16 formed by an inclined cylindrical body, that is, presenting an axis that does not coincide with the axis 30A of the pressurizer 3 but coincides with the axis 90 of the rotor 9; the stator 1 is correspondingly provided with an internal chamber 15, which is constructed and arranged to accommodate the cylindrical appendage 16 so as to allow the cylindrical appendage 16 to rotate within the internal chamber 15 (due to the presence of anti-friction elements in the illustrated ball bearings).

[0061] Thus, it has been found particularly effective and advantageous in the experiments carried out, that the construction of the body of the pressurizer 3 is determined by the association of a single body on a truncated cone (constituting the lower part of the pressurizer 3) topped by a cylinder forming an upper appendix 16, the cylinder 16 being provided with ball bearings or other means of reducing friction relative to the internal chamber 15 in which it is inserted.

[0062] In fact, the shaft 30 of the pressurizer 3 is surmounted by an appendage integral with the shaft 30 itself, angled so as to be perpendicular to the axis 90. The appendage has a cylindrical projection with a circular base coaxial with the axis 90, on which it is mounted a bearing 16 or other antifriction element capable of allowing it to rotate in the internal chamber 15 of the stator.

[0063] This arrangement makes it possible to unload the forces caused by the pressure action of the pressurizer on the lower pump pipe, which forces could otherwise cause the stator to vibrate undesirably by 90° about its axis.

[0064] The rotor 9 is keyed to a shaft 91 mounted to the output of the motor 106; the connection of the motor to its driven shaft 91 is schematically shown in the drawing.

[0065] The rotor 9 is placed inside the base 8 and is rotatable relative to the base 8 , unlike the stator 1 which is, on the contrary, integral with the base 8 when the peristaltic pump 100 is in the configuration of use.

[0066] In addition, the rotor 9 includes a lower part 9B and an upper part 9A, wherein the lower part 9B is directly keyed to the shaft 91 and receives movement from the shaft 91, and the upper part 9A has an inclined upper surface and the upper part 9A vertically lifts the inner core 33 of the pressurizer 3 from the inclined upper surface, which will be described later.

[0067] In practice, the inclination of the core 33 defining the axis of rotation 30A of the pressurizer 3 relative to the bottom surface of the horizontal rotor 9 determines the frustoconical trajectory followed by the pressurizer and the correct inclination required for the pressurizer to roll without crawling on the surface of the lower pump 2.

[0068] The two parts 9A and 9B of the rotor 9 are made integral with each other by screws 93. In the drawings, the rotor may be identified as a whole by 9, or by 9A and 9B to distinguish the upper part and the lower part thereof.

[0069] The base 8 is connected to a fixed flange 80 arranged below and traversed by a shaft 91. The fixed flange 80 is connected to the base 8 by a series of screws 81 passing through a hollow cylindrical crown 82 inside which is housed the lower portion 9B of the rotor 9, the intervention of a bearing 92 making the rotor 9 rotatable relative to the base 8 and its fixed flange 80.

[0070] The fixed flange 80 has a central cylindrical portion 80A which is penetrated by the central portion of the lower part 9B of the rotor integral with the shaft 91. A lip seal 109 is provided between the central portion of the lower part 9B and the cylindrical central portion 80A to ensure sealing.

[0071] In other words, the means or means for motorizing the pressurizer 3 may consist of a motorized base or rotor 9 integral with the pressurizer shaft on which the pressurizer is free to rotate about its axis 30A relative to said motorized base or rotor 9 .

[0072] In particular, with reference to the example shown in the drawings, the rotor 9 is provided with a lower connecting portion 9B which is keyed to the shaft 91 of the gear motor 106. The lower portion 9B of the rotor is integrally attached to the upper portion 9A of the rotor 9 by means of one or more retaining pins 93.

[0073] A friction reducing device or means is provided around the rotor 9, which may include, for example, ball bearings 92; there are one or more seals 109 around the shaft 91, which allow the shaft 91 to rotate relative to the crankcase defined by the central cylindrical portion 80A, and the seals are essentially airtight.

[0074] The latter happens because the appropriate low air pressure is set.

[0075] In other words, the housing is defined as comprising a fixed flange 80 having a planar development and covered by a hollow cylindrical portion 80A, in which the lower portion 9B of the rotor 9 is contained. The base 8 of the pump is integrally attached to the cylindrical portion 80A of the housing, the base 8 of the pump being provided with a plate 7 at the top, which plate 7 can be made of an elastic material, for example. In particular, the plate 7 is inserted into a frame 20A, which is part of a locking and alignment device or means 20 of the base 8. The clamping and alignment device 20 comprises a plate 20B, which defines the stator base 1 and is provided with a second frame 21 complementary to the first frame 20A.

[0076] Referring again to the figures, the axis of the upper appendix 16 of the pressurizer is coaxial with the axis 90 of the rotor 9 and the stator 1 .

[0077] Furthermore, as described above, the pressurizer 3 includes a shaft 30 connected to and integral with the rotor 9 and disposed inside, having an outer frustoconical body 32 defining the aforementioned engagement surface of the pressurizer. The bearing 31 is disposed between the inner shaft 30 and the frustoconical body 32 and is designed to allow the frustoconical body 32 to rotate idly relative to the shaft 30.

[0078] Specifically, the shaft 30 of the pressurizer 3 is a hollow cylinder coaxial with the inner core 33 (which is integral with the rotor as described above) and is interposed between the inner core 33 and the bearing 31 via an outer bushing 34 .

[0079] In the shaft 30, between the inner core 33 and the outer bushing 34, there are elastic connections (elastic connection means or means) 35, 36, 37, which are configured to allow radial play between the two parts. In fact, the inner core 33 is provided with two feed-through seats 38; in the inner surface of the outer bushing 34, two interference pins 35 are stably housed, which in turn slide freely through the feed-through seats 38. These pins allow a moderate radial sliding of the shaft 30, while preventing the shaft 30 from rotating relative to the inner core 33; this movement makes it possible to compensate for the inevitable tolerances in the dimensions of the lower pump tube.

[0080] Coaxial with these pins but attached from the opposite side is a spring 37 which supports at its free end an associated thrust element 36 which comes out of a seat 38 to engage the inner surface of the bushing 34 from the opposite side of the interference pin attachment 35 .

[0081] In this way, a small radial displacement is allowed between the central core 33 connected directly to the rotor and the outer bushing 34 connected via the bearing 31 to the frustoconical body 32 defining the engagement surface with the lower pump 2 .

[0082] In operation of the peristaltic pump 100, as previously described, the pressurizer 3 is guided in rotation by the rotor 9, which supports the pressurizer by defining a truncated track that causes the lower pump to engage with the outer surface of the truncated housing 32. During the rotation of the pressurizer 3, the cylindrical appendix 16 of the pressurizer 3, which is provided with a bearing, rotates in the internal chamber 15 of the stator 1.

[0083] The particular treatment determined by the rotation about the axis 30A of the pressurizer 3 and the rotation of the attachment 16 about the axis 90 contributes to an optimal interaction between the engagement surface 32 of the pressurizer 3 and the lower pump 2 .

[0084] Among the advantageous features of the present invention, the following can be cited:

[0085] The inner wall of the stator 1 forms an angle between 15° and 60° with the axis 90 of the stator. Fig.10 , Fig.11 , Fig.12 The middle is 30°,

[0086] - The outer wall of the truncated cone body of the pressurizer 3 forms an angle with the axis 30A of the pressurizer 3, which is equal to half the difference between the opening of the hollow truncated cone inside the stator 1 and the opening angle A3 of the truncated cone formed by the pressurizer 3, so that during the rotation of the rotor 9 about the axis 90, the orbit defined by the pressurizer 3 is concentric and equidistant with the inner wall of the stator 1 (the wall defining the hollow conical cavity) and maintains the same linear speed relationship with it at every point.

[0087] Therefore, the peristaltic pump 100 includes a base unit 101 and a stator unit 102, wherein the base unit 101 includes at least a pressurizer 3 and a rotor 5, and the stator unit 102 includes at least a stator 1, a lower pump tube 2, a base 8 arranged around the rotor 5 but not integral with the rotor 5 during rotation, and a plate 7 of a material suitable for defining a pneumatic seal, and a device or means for determining a lower pressure that associates the base 8 and the stator unit 102 as a seal, resulting in a stable association between the base unit 101 and the stator unit 102.

[0088] The above-mentioned means or means for facilitating the correct positioning of the lower pump tube or tube portion 2 to the stator 1 may include an internal groove formed by the inner wall 17 of the stator 1, which develops according to a conical helix, the pitch 17A of which is proportional to the value 18 of the width of the tube portion 2 when closed. In fact, in the preferred disposable configuration of the stator unit 102, the lower pump or lower pump tube 2 is already assembled to the stator 1 and other disposable components, which greatly simplifies the blood treatment operation from the point of view of safety and efficiency.

[0089] In this way, it is possible to provide a device or apparatus 200 for venous blood treatment, the device 200 comprising a peristaltic pump 100 as described above and a disposable kit or assembly comprising an oxygenator 103. The lower pump tube 2 has an inlet 22 and an outlet 23, the oxygenator 103 has an inlet 24 and an outlet 25; the outlet 23 of the lower pump tube 2 is connected to the inlet 24 of the oxygenator 103 via a connection formed on the lower side of the stator base, while the inlet 22 of the lower pump tube 2 is connected to the connector 104 via a connection formed on the lower side of the stator base; similarly, the outlet 25 of the oxygenator 103 is connected to the connector 105 via a connection formed on the lower side of the stator base. From these connectors branch off the usual tubing (not shown), for connection to the patient, for the input 104 of blood to be treated and for the return 105 of treated blood, respectively.

[0090] As is known, the oxygenator 103 is a device designed to perform a gas exchange between air and the patient, similar to what occurs inside the lungs, in this particular embodiment, with the goal of CO2 removal, albeit with the presence of an oxidizing component. Advantageously, in the case of an oxygenator, the peristaltic pump 100 is provided with motorization means 106 suitable for determining a flow rate between 50 ml / min and 2000 ml / min. Although it is preferred to limit the flow rate to around 500 ml / min in order to reduce the invasiveness and side effects of the treatment.

[0091] As mentioned above, the contact between the base 20B of the stator 1 and the base 8 of the pump is carried out in such a way as to define a pneumatic seal by contact with a plate 7 made of elastic silicone material, which acts as a seal between the stator base 6 and the pump base 8. Means or means (not shown) are provided for determining a lower pressure or vacuum to associate the pump base 8, the stator base 6 and the stator itself 1 with the seal.

[0092] The means for generating a vacuum may comprise a pump capable of reducing the pressure in the chamber defined by the stator 1 and its base 20B resting on the plate 7 .

[0093] Such a vacuum pump is commercially available (e.g. a diaphragm pump), is not described in detail here or shown in the drawings, but may be of a similar type to that described in European patent EP 2 575 926 B1. The vacuum generated by the pump allows pressure from the outside to be obtained over the entire surface of the stator base 20B and of the stator itself 1, thus ensuring correct clamping of the stator on the machine base.

[0094] This pressure is sufficient to counteract the thrust of the pump on the lower pump tube. The vacuum within the frusto-conical chamber housing the lower pump tube is still effective and helps the tube itself to quickly return to its original shape due to the pressure applied by the inflator, thereby improving the efficiency and consistency of the pumping effect over time.

[0095] In operation, experimental verification has shown that, when the stator 1 is correctly mounted on the base 8, the pump attachment 16 fits into the internal chamber 15 and allows the forces transmitted by the pressurizer against the lower pump tube 2 and thus against the stator itself to be effectively released during the pressurization process. This solution avoids undesirable vibrations of the stator 1, which could impair the effectiveness of the pumping action and the life of the stator itself.

[0096] Experimentally, it has been found that said configuration allows an optimization of the interaction between the lower pump tube 2 housed in the inner wall 17 of the stator 1 and the pressurizer 3 .

[0097] From what has been described so far, the advantages of the present invention are evident, which are determined by its specific features which will be described again below.

[0098] The pressurizer 3 consists of a frustoconical element resulting from the rotation of a line inclined 22.5° from the cone axis in the non-binding example in the attached drawings; smaller and larger holes are acceptable.

[0099] The pressurizer 3 is mounted on an axis 30 integral with the rotor 9. In particular, as described above, the shaft 30 is mounted on a core 33 integral with the rotor 9. This axis 30 is inclined in the example by 15° relative to the axis 5 of rotation of the rotor, but this value is not limiting and different inclinations are possible; in any case, the inclination of the axis 30 should be equal to half the difference between the angle at the vertex of the cone defining the opening of the stator where the lower pump tube is located and the angle at the vertex of the cone defining the opening of the pressurizer, this angle of the pressurizer will necessarily be smaller than that of the stator. The surface of the pressurizer 3 running around the axis 5 of the rotor defines a truncated conical surface having an axis coinciding with the axis 5 of rotation of the rotor.

[0100] The stator 1 has a frustoconical chamber having the same inclination as the surface defined by the pressurizer 3 running around and coaxial with the axis 90 of the rotor, in the example an inclination of 30°.

[0101] The stator has suitable measures (grooves 17) inside said chamber, which are designed to keep the lower pump tube 2 in the correct position while it is subjected to the compression generated by the pressurizer 3 during its orbit. Figure 1 In Figure 1 The lower pump tube 2 in the section to the left of the rotor axis is in a "closed" or compressed configuration, and the section to the right of the rotor axis is in an "open" or uncompressed configuration.

[0102] The measure for forming the groove 17 is characterized by a helical, in particular conical, development, the pitch 30 of which is proportional to the length of the blocked lower pump line section 2 .

[0103] The groove 17 follows the internal contour of the truncated chamber to allow the pressurizer 3 to fully compress the tube until it causes a complete blockage of at least 300° of the track itself.

[0104] With the same pitch but different radii, the profile will gradually move away from the axis of the stator cone to allow the inlet and outlet sections of the lower pump 2 to gradually come into contact with the tube, thereby allowing a gradual transition from a fully open tube state to a fully closed tube state (and vice versa in the outlet section); this solution is intended to minimize the traumatic effects of the pressurizer 3 on the solid components of the blood, such as red blood cells, platelets, etc., and greatly reduce hemolytic damage.

[0105] In the examples shown, see in particular Figure 8 and Fig. 9 , the angles of the inlet and outlet sections of the tube (in Fig. 9 ) covers an arc of 90 degrees, although this value may be appropriately larger or smaller for a total extension of the lower pump tube of greater than 360 degrees (540 degrees in the example shown).

[0106] Experimentally, it has been determined that the preferred construction condition is that the axes of the rotor 9 and the conical chamber of the stator 1 coincide and that the axis 30A of rotation of the pressurizer 3 mounted on the stator support 1 passes through a point A belonging to the extension of the aforementioned common axis.

[0107] This ensures that the direction of the vector of the compressive force generated by the pressurizer 3 on the tube 2 and on the stator 1 is at every point perpendicular to the tangent to the stator surface 1 at that point, so as to avoid different force components on the tube itself, which would tend to displace the tube from its default position.

[0108] On the pressurizer 3 there is suitably present an extension concentric with the axis of rotation of the rotor, situated at the distal end of the retainer of the pressurizer, which helps to unload from the rotor itself the forces necessary for the pump under compression exerted by the pressurizer on the stator, by being inserted into a compatible hole present on the stator and also concentric with the axis of rotation of the rotor. This reduces the stresses that the stator must withstand, by allowing a lighter structure. The remaining forces will be borne by the attachment of the stator to its own base, and transmitted from it to suitable guides on the stator 102 and on the base of the pump 101.

[0109] The assembly of the stator 1 and its base 20B defines in practice a disposable kit or assembly and may be provided from a suitable disposable plastic material (transparent polyvinyl chloride or polycarbonate, to name a few) to allow control of the operation and integrity of the lower pump tube 2.

[0110] The locking in place of the aforementioned disposable set 102 can advantageously be achieved with the aid of a partial atmospheric vacuum. In addition to the possibility of firmly coupling the pump and its base to the above-mentioned assembly, the partial vacuum has the advantages of facilitating the filling of the tube upstream of the action of the pump, requiring a lower pump tube 2 with a smaller wall thickness (because the force allowing the tube to recover its rest shape does not depend solely on its elastic memory, but also on the advantages of the atmospheric vacuum outside it), and the advantages of a higher flow rate with the same outer diameter of the lower pump tube and the same rotation speed, and the advantages of a more stable performance of the pump over time.

[0111] Another fundamental advantage of implementing the present conical peristaltic pump 100 is that it can be easily connected to its own disposable kit 101, 102 without the need to operate or use translation and fixing mechanical devices or means; it is sufficient to place the kit 102 on the pump base 101, bring the kit 102 closer in the direction of the axis 90, align the kit 102 along the locking parts 20A and 20B, and the action of the vacuum will provide the correct positioning of the kit and hold it in this position.

[0112] A further advantage is that by rotating the rotor 9 in the appropriate direction, i.e. pressing the tube 2 in the direction of increasing radius towards the spiral, wherein the tube 2 is pushed by the device housing (indicated by the internal groove formed on the wall 17), the volume of the pumped blood is shifted towards the larger tube volume (given by the increasing radius of curvature at the same covered angle).

[0113] This behavior eliminates overpressure within the tubing itself, which could cause hemolytic "shear stress" injuries, thereby taking advantage of the atraumatic behavior of the pump itself.

[0114] The device 200, peristaltic pump 100, oxygenator 103 and all circuits and connected parts will be appropriately equipped with elements such as pressure gauges to monitor pressures (suction, pre-filter and return); safety shut-off devices (or "clamps") that intervene in the event of an alarm; bubble sensors (not shown), etc.

[0115] In general, as is apparent from the description of the examples shown above, the present invention consists of a peristaltic pump comprising: a tube portion or lower pump 2 between an inlet and an outlet for passing the pumped fluid, a pressure being applied to the tube portion 2, the pressure being suitable for producing a fluid flow from the inlet towards the outlet; a stator 1, the stator 1 being provided with an internal chamber defined or delimited by corresponding walls, against which the tube portion is pressed; a device or means 17 for attaching the tube portion 2 to the stator 1; a pressurizer 3, the pressurizer 3 being cyclically moved along a trajectory to engage the lower pump tube 2 by applying pressure on the tube portion 2 by means of corresponding engaging surfaces; a device or means for motorizing the pressurizer 3, comprising a motorized base or rotor 9, the base or rotor 9 rotating about an axis 90, and the base or rotor being integral with the pressurizer 3 in its own rotation, the pressurizer 3 being free to rotate about its axis 30 relative to the motorized base or rotor 9.

[0116] The peristaltic pump 100 is characterized by the following facts: the inner wall of the stator 1 develops along a conical surface, which has a first hole A1 and an axis coinciding with the rotation axis 90 of the rotor 9; the engaging surface of the pressurizer 3 is a conical surface having a second hole A3, which is different from the first hole A1 and is lower than the first hole A1; the pressurizer 3 is supported by a shaft 30, which has the same axis 30A as the pressurizer 3, and the axis 30A does not coincide with the rotation axis 90 of the rotor 9, but is inclined relative to the axis 90, and the pressurizer 3 is integral with the rotor 9.

[0117] It is also apparent from the above description that the pump according to the invention may have one or more of the following features, which may even be combined or coupled with each other:

[0118] The axis 30A of the pressurizer 3 is inclined relative to the axis 90 of the rotor 9 by an angle equal to half the difference between the first opening angle A1 of the stator and the second opening angle A3 of the pressurizer.

[0119] The axis of rotation 90 of the rotor 9 , the contour of the conical surface of the inner wall of the stator 90 , the axis of the pressurizer 30A and the contour of the conical surface to which the pressurizer itself 30A belongs intersect at a common point A.

[0120] - The upper distal end of the pressurizer 3 (i.e. the upper side of the truncated cone 32 forming the pressurizer 3) is firmly connected with a cylindrical appendix 16, which forms the upper part of the pressurizer 3 and is inclined so as to define a cylindrical protrusion 16 coaxial with the axis 90 of the rotor 9.

[0121] The stator 1 is provided with an internal cavity 15 suitable and arranged to house a cylindrical appendix 16 , allowing the cylindrical appendix 16 to rotate inside the internal cavity 15 .

[0122] -The peristaltic pump 100 includes a base unit 101 and a stator unit 102, wherein the base unit 101 includes at least a pressurizer 3 and a rotor 5, and the stator unit 102 includes at least a stator 1, a lower pump tube 2, a base 8 arranged around a rotor 9, the base 8 is not integral with the rotor during rotation, a plate 7 made of a material suitable for defining a pneumatic seal, and a device or means for determining a lower pressure to associate the base 8 and the stator unit 102 as a seal, thereby bringing about a stable association between the base unit 101 and the stator unit 102.

[0123] The pressurizer 30 comprises an internal shaft 30 provided with an inner core 33 connected to the rotor 9 and an outer frustoconical body 32 defining the pressurizer engagement surface, wherein a bearing 31 is provided between the internal shaft 30 and the frustoconical body 32, the bearing 31 enabling the frustoconical body 32 to rotate idly relative to the internal shaft 30 and the inner core 33.

[0124] The internal shaft 30 comprises an inner core 33 integral with the rotor 9 and an outer bushing 34 connected by a bearing 32 and provided with elastic connections 35 , 36 , 37 between them configured to allow radial play between the two parts.

[0125] Furthermore, in general, the present invention also relates to an apparatus or device 200 for venovenous blood treatment, comprising a peristaltic pump 100 according to any of the preceding claims and a disposable kit or assembly comprising an oxygenator 103, wherein the lower pump tube 2 is provided with an inlet 22 and an outlet 23, and the oxygenator 103 is provided with an inlet 24 and an outlet 25, the outlet 23 of the lower pump tube 2 being connected to the inlet 24 of the oxygenator 103, the inlet 22 of the lower pump tube 2 and the outlet 25 of the oxygenator 103 being provided with means or means for connection to a patient to be treated by connection to connection means 104, 105, the connection means 104, 105 being provided for inputting blood to be treated and returning treated blood, respectively.

[0126] Furthermore, in the device 200, the peristaltic pump 100 is equipped with a drive device 106 suitable for determining a flow rate between 50 ml / min and 2000 ml / min.

[0127] The described matter is understood by reference to the matter shown in the accompanying drawings which constitute an implementation form of the invention.

[0128] Furthermore, the details of implementation may still vary equally in shape, size, arrangement of elements, nature of the materials used, without, however, departing from the idea of ​​the solution adopted or the scope of the inventive concept and therefore remaining within the scope of protection conferred by the appended claims.

Claims

1. A peristaltic pump, comprising: a pipe section or lower pump pipe (2) between the inlet and the outlet, the lower pump pipe (2) being used for the fluid to be pumped to flow through, a pressure being exerted on the lower pump pipe (2), the pressure being suitable for generating a direct flow of the fluid from the inlet to the outlet; A stator (1), the stator (1) being provided with an internal chamber defined by corresponding walls, the lower pump tube (2) being pressed against the corresponding walls; means (17) for fixing the lower pump tube (2) to the stator (1); A pressurizer (3) which moves cyclically along a trajectory to engage with the lower pump tube (2) by applying pressure on the lower pump tube (2) through corresponding engagement surfaces; Means for motorizing the pressurizer (3), said means comprising a motorized base or rotor (9) which rotates about an axis (90), said base or rotor being integral with the pressurizer (3) during rotation, said pressurizer being free to rotate relative to said base or rotor (9) about its axis (30A); Features: The inner wall of the stator (1) extends along a conical surface having a first opening angle (A1) and an axis coinciding with the rotation axis (90) of the rotor (9); The engaging surface of the pressurizer (3) is a conical surface having a second opening angle (A3), and the second opening angle (A3) is different from and smaller than the first opening angle (A1); The pressurizer (3) is supported by a shaft (30), and the axis (30A) of the shaft (30) of the pressurizer (3) does not coincide with the rotation axis (90) of the rotor (9) and is inclined relative to the rotation axis (90) of the rotor (9) which is integral with the shaft.

2. The peristaltic pump according to claim 1, characterized in that: The angle at which the axis (30A) of the pressurizer (3) is inclined relative to the rotation axis (90) of the rotor (9) is equal to half of the difference between the first opening angle (A1) of the stator and the second opening angle (A3) of the pressurizer, and the rotation axis (90) of the rotor (9), the contour line of the conical surface of the inner wall of the stator (90), the axis (30A) of the pressurizer and the contour line of the conical surface of the pressurizer intersect at a common point (A).

3. The peristaltic pump according to claim 1 or 2, characterized in that: A cylindrical appendage (16) is integrally fixed to the upper distal end of the inner shaft (33), the cylindrical appendage being inclined so that the cylindrical appendage has a cylindrical protrusion (16) coaxial with the axis (90) in a plane opposite to the plane in which the cylindrical appendage is fixed to the inner shaft and perpendicular to the axis (90) of the rotor (9), and the stator (1) is provided with an internal chamber (15), which is shaped and arranged to accommodate the cylindrical appendage (16) to allow the cylindrical appendage (16) to rotate within the internal chamber (15).

4. Peristaltic pump according to one of the preceding claims, characterized in that The peristaltic pump (100) comprises a base unit (101) and a stator unit (102), wherein the base unit (101) comprises at least the pressurizer (3) and the rotor (5), and the stator unit (102) comprises at least the stator (1), the lower pump tube (2) and a base (8), wherein the base (8) is arranged around the rotor (9) and is not integral with the rotor (5) when rotating, and the base is provided with a plate (7) made of a material suitable for defining a pneumatic seal, which is used to determine a low pressure to sealably associate the base (8) and the stator unit (102), thereby forming a stable association between the base unit (101) and the stator unit (102).

5. Peristaltic pump according to one of the preceding claims, characterized in that The pressurizer (30) comprises an inner shaft (30) provided with an inner core (33) connected to the rotor (9) and an outer frustoconical body (32), the outer frustoconical body defining the engagement surface of the pressurizer (3), a bearing (31) being provided between the inner shaft (30) and the frustoconical body (32), the bearing (31) being adapted to allow the frustoconical body (32) to rotate freely relative to the inner shaft (30) and the inner core (33).

6. The peristaltic pump according to claim 5, characterized in that: The inner shaft (30) comprises an inner core (33) and an outer sleeve (34), wherein the inner core (33) and the outer sleeve (34) are connected via a bearing (31), the inner core (33) is integral with the rotor (9), and an elastic connector (35, 36, 37) is provided between the inner core (33) and the outer sleeve (34), wherein the elastic connector is configured to allow a radial gap between the two components.

7. An apparatus (200) for venovenous blood treatment, characterized in that A disposable kit comprising a peristaltic pump (100) according to any one of claims 1 to 6 and an oxygenator (103), wherein the lower pump tube (2) is provided with an inlet (22) and an outlet (23), the oxygenator (103) is provided with an inlet (24) and an outlet (25), the outlet (23) of the lower pump tube (2) is connected to the inlet (24) of the oxygenator (103), the inlet (22) of the lower pump tube (2) and the outlet (25) of the oxygenator (103) are provided with connection devices (104, 105) for connecting to a patient, and the connection devices (104, 105) are respectively used for the entry of blood to be treated and the return of treated blood.

8. The device (200) for venovenous blood treatment according to claim 7, characterized in that The peristaltic pump (100) is provided with a drive device (106) suitable for determining a flow rate between 50 ml / min and 2000 ml / min.

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