DEVICE FOR EXTRACORPOREAL TREATMENT OF BLOOD

Description

Field of invention

[0001] The invention relates to a drive device for a peristaltic pump of a medical device. State of the art

[0002] There are several possible causes for a person to suffer from kidney failure where the temporary / permanent and partial / total cessation of function forces the person to use extracorporeal devices that totally or partially replace their own kidneys. Dialysis is a blood purification technique. It allows a patient suffering from such a disease to eliminate impurities such as urea and excess water from the body that would normally be eliminated by normally functioning kidneys.

[0003] It is possible to distinguish two types of renal failure related to the duration of the disease and requiring care that can be significantly different: chronic renal failure and acute renal failure. Chronic renal failure requires the patient to undergo lifelong treatment at a certain frequency. For this, the patient can undergo this treatment in a medical center or at home using a peritoneal dialysis or hemodialysis machine. Acute renal failure is a temporary illness where the patient needs a machine to temporarily replace the functions of his kidneys. In this case, the patient undergoes continuous renal replacement therapy. Peritoneal dialysis and continuous renal replacement therapy are very different, as are the techniques and / or devices used: Peritoneal dialysis uses the patient's peritoneum, which is the natural membrane that surrounds the walls of the abdomen and the organs located in the abdomen (liver, intestines, etc.). The peritoneal membrane has a very large surface area and contains many blood vessels. It therefore acts as a natural filter. Many patents disclose systems for performing peritoneal dialysis, some of which use cassettes (EP 1 648 536 A2, EP 0 471 000 B1, EP 1 195 171 B1, EP 1 648 536 B1) for injecting and withdrawing fluid into the patient's peritoneum. Continuous Renal Replacement Therapy (CRRT) is a process that involves continuously extracting blood from the patient, treating it through a filter, usually a dialyzer, and then reinjecting the treated blood into the patient. Two main principles are used using the filter: ∘ Diffusion allows solute molecules to pass through a semi-permeable membrane along a concentration gradient. Solutes move from the most concentrated medium (the blood) to the least concentrated medium (the dialysate) to be distributed evenly on both sides of the filter membrane. ∘ Convection allows the simultaneous transfer of water and its solute content across the semi-permeable membrane, thanks to the transmembrane hydrostatic pressure gradient.Thus, the solutes move from the environment where the pressure is highest (blood compartment) to the environment where the pressure is lowest (dialysate compartment). There are different techniques of continuous extra-renal purification using one or both principles: slow continuous ultrafiltration (SCUF: Slow Continuous Ultra-Filtration), continuous venovenous hemofiltration (CWH: Continuous Ceno-Venous Hemofiltration), continuous venovenous hemodialysis (CVVHD: Continuous Veno-Venous Hemodialysis), continuous venovenous hemodiafiltration (CWHDF: Continuous Veno-Venous Hemofiltration), plasma exchange (TPE: Therapeutic Plasma Exchange) and hemoperfusion (also called Blood Detoxification). To date, no device is capable of offering all of these treatments without the intervention of experienced healthcare personnel. Furthermore, these techniques are mainly used in intensive care settings.Unfortunately, these techniques use bulky equipment that can interfere with other patient care. In addition, these devices are complex, have many consumables, and require significant changes to perform the various techniques mentioned above. This requires that staff receive specialized training.

[0004] An example of the prior art is known, for example, from document US6036459. Description of the invention

[0005] The invention is defined by the features of independent claim 1. The dependent claims relate to particular embodiments. The passages below provide additional context to better understand the invention. Only the invention as claimed is protected. General Description of Disclosure

[0006] The disclosure relates to multiple improvements for medical devices, means and / or methods used for medical devices.

[0007] This application claims priority from application number PCT / IB2012 / 055972, filed on October 29, 2012 in the name of Debiotech.

[0008] A first aspect of the disclosure relates to a single cassette for performing one or all of the different continuous extra-renal purification techniques: slow continuous ultrafiltration (SCUF), continuous venovenous hemofiltration (CWH), continuous venovenous hemodialysis (CVVHD), continuous venovenous hemodiafiltration (CVVHDF), plasma exchange (TPE) and hemoperfusion. In one embodiment, the device can also be used in the context of peritoneal dialysis where certain elements and / or features might not be used or might be used for other functionalities such as sampling or others. In one embodiment, the cassette is partially or fully integrated into the dialysis device or some of these elements are part of said device (for example the pumping system, the sensors, the filter, etc.).) or are physically separated from the cassette (for example the filter, supply means, reservoirs, sensors, heating means, etc.) or are optional. Preferably, said cassette and the dialysis device are both separate. The cassette is disposable while the device is reusable. This means that the cassette can be replaced for each treatment (single use, replacement of the cassette after each use) and that the device can be used several times with different cassettes. Said cassettes are designed to cooperate physically and / or mechanically with the device and / or vice versa.In addition, the use of a single cassette makes it possible to simplify the use of said device, reduce operator errors thanks to this simplification, automate the treatment without the intervention of nursing staff, limit the number of cassette types, simplify programming, allow the use of the device in the patient and / or limit the space occupied by the device.

[0009] According to a second aspect of the disclosure, the device may comprise only 3 main pumps to carry out at least one or all of the techniques cited in the state of the art (SCUF, CW, CWH, CWHDF, TPE and hemoperfusion).

[0010] According to one embodiment, the device comprises a blood filtration means, at least one liquid supply means, two patient pipes - an outlet pipe taking the blood to be treated and an inlet pipe reinjecting the treated blood into said patient - (or a single pipe in the case of peritoneal dialysis or a pipe with two separate lumens), a filtrate recovery means, three fluid pumps, a cassette composed of channels and valves so as to direct the fluids, and a controller which controls the pumps, the opening and closing of said valves according to the desired treatment.

[0011] Said casette comprises at least one distribution chamber comprising a single inlet channel, at least two outlet channels and at least two connection chambers comprising at least two inlet channels and one outlet channel. Preferably, said distribution chamber comprises one inlet channel and three outlet channels controlled by the controller (automatically, programmed and / or controlled) in order to allow a fluid to be injected into the blood filtration means, into the blood before the blood filtration means (pre-dilution) and / or after the blood filtration means (post-dilution). Thanks to this distribution chamber, the device can carry out any dialysis treatment without the caregiver (or other specialist) being present to configure the specific connections of each treatment.

[0012] Said treatment system further comprises at least three fluid paths. The first fluid path connects said blood filtration means to the filtrate recovery means. It comprises a series of channels and a dedicated pump. The second fluid path is dedicated to blood circulation. It comprises at least two connection chambers, a series of channels, said blood filtration means, said patient hoses and a dedicated pump. The third fluid path comprises a liquid supply means, at least one dedicated pump, a series of channels, a distribution chamber and, optionally, a heating means. Said distribution chamber comprises at least three separate outlet channels: a first outlet channel supplying the second fluid path upstream of the filtration means (to carry out a pre-dilution of the blood before being filtered by the filtration means), a second outlet channel supplying the second fluid path downstream of the filtration means (to carry out a post-dilution of the blood after having been filtered by the filtration means), and a third outlet channel supplying said filtration means.

[0013] In one embodiment, the two connection chambers and the distribution chamber are supplied with positive pressure by two pumps placed upstream of said chambers.

[0014] Said first connection chamber makes it possible to connect the second fluid path to the third fluid path upstream of the filter (pre-dilution technique). It comprises an inlet channel coming from the second fluid path, an inlet channel coming from the third fluid path and an outlet channel allowing the blood to flow towards the filter. Said inlet channel coming from the third fluid path may comprise a valve controlled by said controller, a flow restrictor and / or a pump.

[0015] Said second connection chamber makes it possible to connect the second fluid path to the third fluid path downstream of the filter (post-dilution technique). It comprises an inlet channel coming from the second fluid path following its flow through the filter, an inlet channel coming from the third fluid path and an outlet channel towards the patient.

[0016] According to certain embodiments, the invention may further comprise: A supply means for injecting an anticoagulant into the second fluid path either directly into the patient outlet pipe or furthest upstream in the cassette using a connection chamber which allows the anticoagulant to be mixed with the blood (fluid of the second fluid path), and / or A supply means for injecting a product inhibiting the anticoagulant into the second fluid path either directly into the patient inlet pipe or furthest downstream in the cassette using a connection chamber which allows said product to be mixed with the blood (fluid of the second fluid path).

[0017] A third aspect of the disclosure relates to the structure of the cassette, when a fluid path (coming for example from a liquid supply means) connects to another fluid path, the cassette preferably comprises a connection chamber allowing the intersection of said two fluid paths. This connection chamber can thus allow mixing of the fluids coming from said fluid paths. In addition, at least one of said inlet channels of said connection chamber can comprise a valve, so that the controller can select the determined fluid(s) which will flow into the connection chamber according to the desired, programmed or controlled treatment.

[0018] According to a fourth aspect of the disclosure, a heating means is located in the third fluid path between the main dialysate pump and the distribution chamber. Said heating means is preferably a flexible bag supplied with positive pressure by said pump. In one embodiment, a second pump is located between the distribution chamber and a connection chamber. Preferably, the distribution chamber is connected to a first and second connection chamber. The first connection chamber allows for pre-dilution of the fluid flowing in the second fluid path (i.e. dilution of the blood before the filtering means) while the second connection chamber allows for post-dilution of the fluid of said second fluid path (i.e. dilution of the blood after the filtering means).The first pump is a precision pump and it makes it possible to know precisely the quantity of fluid that will be mixed in the blood in pre and post dilution. The second pump is located downstream of one of the two connection chambers, the other and / or the two connection chambers can include a valve. This second pump is a distribution pump making it possible to distribute a determined quantity of fluid between the first and the second connection chamber. This type of system can include one or more other connection chambers. Preferably, the system includes a pressure sensor and the heating means can serve as a temporary storage means.

[0019] To optimize the operation of the treatment system, the invention also discloses the following elements which can be used with or without the cassette described above: A means and method for calibrating the pumps of the first and third fluid path, A pressure sensor remote from the fluid path, An energy-saving linear actuator, A drive device used for peristaltic pumps, A means of damping pressure peaks. Means and method of calibrating pumps and / or sensors of the first and third fluid path :

[0020] Some continuous extra-renal purification techniques require precise knowledge of the quantity of volume injected and withdrawn respectively from the third and first fluid paths. Usually, the devices comprise two scales, one scale dedicated to the dialysate and another dedicated to the filtrate. The present invention may comprise the same scale system, however these scales are very sensitive and bulky (because they must be able to contain all the fluids). Other devices have cavities whose volume capacity is precisely known. These cavities are located directly on the first and third fluid paths (an intermediate wall being used to avoid mixing the two fluids) and they are successively filled and then emptied of the fluids from said fluid paths. When the cavity fills with dialysate, the cavity empties of the filtrate previously contained in said cavity and / or vice versa.These devices may contain several of these cavities. However, unlike the device of the present invention, these devices do not allow continuous operation; they operate by a succession of steps of filling and emptying the fluids contained in said cavities.

[0021] According to a fifth aspect of the disclosure, the treatment system has a means of calibrating said pumps in order to accurately know said volumes. The system comprises: ∘ At least two volumetric measurement means (sensor, mass flow system, volumetric pump, peristaltic pump, scale, etc.), one of which measures the quantity of liquid flowing through the third fluid path and one of which measures the quantity of liquid flowing through the first fluid path; ∘ a means of sampling the first and third fluid paths; ∘ a common means of measuring the volumes sampled.

[0022] Said common measuring means measures the quantity of fluid taken by the sampling means and makes it possible to compare the volumes taken and to calibrate said pumps and / or said volume measuring means.

[0023] In one embodiment, said pumps are considered as said volume measuring means because each actuation corresponds to a given volume.

[0024] In another embodiment, the volume sensors are separate from the pumps and continuously measure the volumes propelled by said pumps. In the event of a drift in the pumped volumes, the controller can correct the actuation of said pumps to correct the volumes or the volume differential.

[0025] A sixth aspect of the disclosure relates to a method for calibrating pumps used to propel fluids from the first and third fluid paths and / or sensors placed in said fluid paths. The method further allows for calibrating said pumps before and / or during execution of the treatment. Pressure sensor remote from the fluid path :

[0026] A seventh aspect of the disclosure relates to a means for measuring the pressure of a fluid. In one embodiment, the treatment system comprises at least one pressure sensor in at least one of said fluid paths. The present document discloses a fluid distribution system (preferably a cassette) which makes it possible to sample and / or deliver a fluid FI1 and to measure the pressure of said fluid FI1. The system comprises a rigid body composed of at least one fluid path through which said fluid FI1 flows, of at least one channel distinct from said fluid path. Said channel makes it possible to connect said fluid path to a measurement zone. The system may comprise at least one opening covered by a flexible membrane forming said measurement zone. The membrane is shaped to receive a pressure sensor.

[0027] A fluid FI2 different from the fluid FI1 is contained in said measuring zone. The fluid FI2 at least partially fills the measuring zone and / or said channel. Said fluid FI2 makes it possible to transmit the pressure of the fluid FI1 to said membrane.

[0028] The purpose of this channel is that the fluid FI1 cannot come into contact with said membrane or that the fluid FI1 at least partially wets said membrane. Thus, the channel can be shaped so that said fluid FI1 limits, slows down and / or controls the flow of the fluid FI1 through said channel. It has a shape and a length allowing this function and / or can comprise a means of containing the fluid FI1 (such as a membrane, a hydrophilic, hydrophobic filter, etc.). Preferably, the measurement zone is filled with both fluids FI1 and FI2 and / or the fluids FI1 and FI2 are in contact with the membrane. Energy-saving linear actuator :

[0029] In one embodiment, the processing system comprises at least one energy-efficient linear actuator. The present document discloses an innovative principle for controlling a linear actuator consuming a low amount of energy and for controlling the position of a valve. This actuator can be included in a system as described above but also in any device using a linear actuator. In particular, the actuator must offer two basic positions, namely closed valve (where the piston is in a first position) and open valve (where the piston is in a second position). The piston can also have a third position corresponding to a state where the actuator piston is disengaged from the valve foot.

[0030] To ensure the function of a linear actuator, two different techniques are usually used: the electromagnet or the brushless motor mounted with a worm screw and a nut. The main disadvantage of these two techniques is that they consume energy to maintain a position. The present invention discloses a linear actuator comprising at least two stationary positions with low energy consumption and a rapid return to a safety position. Furthermore, the actuator, disclosed by the present document, consumes no or a very low amount of energy to maintain its different positions.

[0031] The eighth aspect of the disclosure thus relates to a linear actuator comprising a rotary electric motor, a piston and means which are interposed between the electric motor and the piston transforming the rotational movement of the motor into a linear displacement of the piston. Said interposed means comprise at least one peripheral ramp arranged inside said piston, at least one guide means allowing the piston to guide the translational movement and at least one support means fixed directly or indirectly to the rotor of said electric motor. Said support means is shaped so as to cooperate with said peripheral ramp. In one embodiment, said actuator further comprises at least one compression means which exerts a force against the piston in the direction of the distal end of the piston. The ramp comprises at least one threshold making it possible to obtain at least one stationary position without consuming energy.At least one threshold is positioned at the top of said ramp. In a preferred embodiment, this threshold is followed by a passage allowing the piston to free itself from the constraints exerted by the support means.

[0032] According to a ninth aspect of the disclosure, the actuator makes it possible to guarantee a given occlusion pressure when the valve is in the closed position. The position of the valve without contribution from the actuator is preferably a closed position. To guarantee good occlusion, the actuator has a compression means to ensure sufficient pressure to occlude the valve against its seat when the piston is in the first position. Said compression means makes it possible to obtain a third position (when the piston is not engaged with the valve) where the piston is further away from the actuator support. The transition from the third position to the first position is carried out when the piston engages with the valve. In other words, when the cassette is placed in the device.Thus, the compression means forces the piston to exert an initial force against the valve which transmits this force against the valve seat ensuring occlusion of the fluid path when the piston is in the first position. In one embodiment, said compression means may be on the actuator support or in said piston. In other words, when said actuator piston is engaged with the valve foot, i.e. in the first position, a compression means provides pre-stressing to ensure good occlusion. Said compression means may be mounted in the actuator or on the actuator support, said compression means makes it possible to obtain a third position where the actuator piston is further from the actuator support than in the first and second positions. The occlusion pressure depends on the design of the valve and the sizing of the compression means. Drive device used for peristaltic pumps :

[0033] The invention relates to a drive device used for a pump. When using said treatment system, the cassette is inserted into a cycler which includes sensors, linear actuators (to open and close the valves) and means for driving the rollers of the peristaltic pump. In order to ensure proper operation of the system, it is important that all the elements are correctly aligned (sensor, actuator, actuating means, etc.). However, a difference between the theoretical center point of the pump head and the actual center point may exist. This difference creates problems of alignment of the actuators and sensors respectively on the valves and the measurement zones of the cassette. Thus, guiding means make it possible to overcome this alignment problem for the sensors and actuators but transfer the difference to the pumping system.Thus, more or less significant constraints can be exerted on the pump elements, which can affect the precision of the peristaltic pump. This phenomenon is all the more significant when there are many pumps.

[0034] In order to relax manufacturing tolerances and ensure the precision of peristaltic pumps, the invention discloses a pump drive device comprising a floating shaft driven by a drive means fixed to a rotor. The floating shaft comprises an integral base / cover assembly which forms a cavity inside which said drive means is at least partially circumscribed. Furthermore, said drive means comprises a rigid body shaped to cooperate with the walls of said cavity in order to allow restricted freedom of the floating shaft relative to the axis of said rotor. The floating shaft makes it possible to offset the axis of the pumping system in order to minimize or even eliminate any stresses exerted by the pump shaft on the theoretical pumping axis of the cassette. Means of damping pressure peaks :

[0035] An eleventh aspect of the disclosure relates to a means of damping pressure peaks.

[0036] The quantity of a pumped fluid can be influenced by the constituent elements of the system. These elements can be the pumping mechanism, the valve mechanism, the means of supplying liquid (tubes, reservoirs, etc.). In particular, the pumping mechanism of a peristaltic pump can cause pressure variations. Thus, a pressure wave is created and propagates in the fluid path(s) each time the rollers come into contact with the flexible tube. This propagation is attenuated or reinforced by several factors such as: the type of liquid, the length of the fluid path, the restrictions, the type of materials of the system, the quantity of liquid delivered by the pumping mechanism, the type of pump, the characteristics of its components (flexible tube, etc.), the pressure downstream of the pump, etc.

[0037] One of the improvements of the invention makes it possible to reduce the amplitude of pressure peaks as well as their influence on the pumped quantity. This reduction is achieved by adding to the fluid path a means designed to absorb pressure peaks.

[0038] Another advantage of this peak reduction is also to obtain a more constant pressure which increases patient comfort. In this embodiment, peak damping can be carried out downstream of the pump during an injection to the patient and upstream when the pump withdraws fluid from the patient (in particular during peritoneal dialysis).

[0039] This damping means may be a cavity filled with a compressible fluid such as air. This damping means may be a flexible element that is deformed by pressure peaks and returns to an equilibrium state. This flexible element may be, for example, a polymer membrane in the wall of the fluid path. List of figures

[0040] The invention will be better understood below by means of a few illustrated examples. It goes without saying that the invention is not limited to these embodiments. Figure 1 schematizes the blood processing system Figure 2 schematizes the use of the cassette applying a slow continuous ultrafiltration treatment Figure 3 schematizes the use of the cassette applying a continuous veno-venous hemofiltration treatment Figure 4 schematizes the use of the cassette applying continuous veno-venous hemodialysis treatment Figure 5schematizes the use of the cassette applying a continuous veno-venous hemodiafiltration treatment Figure 6 schematizes the use of the cassette applying plasma exchange treatment Figure 7 schematizes the use of the cassette applying a hemoperfusion treatment Figure 8 schematizes the system with several means of liquid supply Figure 9 schematizes the system with a recirculation of the second fluid path and rejection Figure 10 schematizes the system with the reference sensor Figure 11 shows the rigid body of the cassette including a fluid path and its channel for pressure measurement Figure 12 shows the body of the cassette and the membrane which covers the measuring area Figures 13 and 13' schematize the location of the remote sensor of a fluid path Figure 14 shows an exploded view of the linear actuator Figure 15 shows a sectional view where the valve is coupled to the nipple / piston Figure 16 shows two detailed views of the piston Figure 17 shows two partially cutaway views of the piston in third position, valve (not shown) uncoupled Figure 18 shows two partially cutaway views of the piston in first position, valve coupled (not shown) Figure 19 shows two partially cutaway views of the piston moving from the first to the second position, valve coupled (not shown) Figure 20 shows the piston in second position, valve coupled (not shown) Figure 21 shows the piston in second position which instantly moves to first position, valve coupled (not shown) Figure 17', 18', 19' , 20' and 21' illustrate the cooperation between the ramp and the support means driven by the motor (not shown) Figure 22 shows an exploded view of the peristaltic pump drive device according to the invention Figure 23 shows a sectional view of the drive device of the peristaltic pump according to the invention Figure 24shows on a graph pressure spikes caused by a pump Figure 25 and 26 show two different designs of the damping means Figure 27 schematizes a minimal embodiment of the blood processing system Figure 28 And 29 schematize more complex embodiments of the blood processing system Figure 31 schematizes the use of the additional pump for fluid distribution Figure 32 and 32' illustrates the use of a linear actuator Figure 33 represents 3 graphs used by an actuator control system Numerical references used in figures

[0041] 1Patient 2Cassette 2'Cassette including pumps 3Blood filtration means 4Heating means 5Outlet tube from the patient 6Inlet tube towards the patient 7Safety element 8Blood inlet into the filter 9Dialysate inlet into the filter 10Filtrate outlet from the filter 11Blood outlet from the filter 12Filter membrane 13Flow adjustment means 14Blood processing system 15Third fluid path volume sensor 16Reference volume sensor 17First fluid path volume sensor 100Fluid distribution system 101Measuring area 102Channel 103Fluid path 104Membrane 105Rigid cassette body 106Opening 107Pressure sensor 108Hydrophobic filter 200Linear actuator 201DC motor with reducer 202Rigid casing 203Groove in the rigid casing 204Sensor 205Compression means 206Magnet 207Piston 208Motor shaft 209Transverse shaft 210Piston to nipple connection element 211Nipple 212Valve213Valve seat 214Ramp 215Threshold at the top of the ramp 216Guide means 217Distal end of the piston 218Proximal end of the piston 219Passage 220Direction 1 221Direction 2 300Drive device 301Floating axis 302Cover 303Drive means 304Body of the drive means 305Longitudinal axis 306Perpendicular axis 307Fixing screw 308Hard elements 309 and 309'inner walls of the cavity 310Rotor / motor 311Base 312Cooperating element 313Cavity 313'Second cavity 320Roller 321Roller axis 322Rigid part 323Flexible part 401Pressure curve 402Mean pressure curve 403Flexible membrane 404Fluid path wall 405Compressible fluid (e.g. gas) 406Fluid 500Patient 5011st chamber 5022nd chamber 5033rd chamber 5044th chamber 5055th chamber 5066th chamber 5071st pump 5082nd pump 5093rd pump 5104th pump (optional) 5115th pump (optional) 5126th pump (optional) 513Filter 5141st fluid supply means 5152ndfluid supply means 5163rd fluid supply means 517Fluid recovery means 518Pressure sensor 519Closing means (e.g. valve) 520Flow restriction or closing means 521Sensor 522Heating means 600Patient 601Casette 602Dialysis machine / box 603Fluid supply means 604Fluid recovery means 605Processor 606Sensors 607Actuators (Pump, valve,...) 608Screen 609Acquisition and / or other means, e.g. energy supply means 610Memory 700Fluid distribution system 701Main fluid path 702Precision pump 703Flexible bag (e.g. bag flexible heating) 704 and 704'Secondary fluid path 705Valve 706Pressure sensor 707Additional pump 708Processor 800Control system 801Moving part of the actuator 802Sensor element 1 803Sensor element 2 804Fixed part of the actuator 805Control element (processor and / or other element) C1Firstdistribution chamber C1.1Additional connection chamber C1.2Additional distribution chamber C2First connection chamber C3Second connection chamber C4Third connection chamber C5Fourth connection chamber C6Fifth connection chamber C7Second distribution chamber C8Sixth connection chamber C9Seventh connection chamber F1First liquid supply means F2Second liquid supply means F3Third liquid supply means F4Filtrate recovery means F5Blood recovery or sampling means FI1Fluid 1 FI2Fluid 2 FI3Fluid 3 P1Pump of the second fluid path (Blood) P2Main pump of the third fluid path (Dialysate or substitution) P2Additional pump of the third fluid path P3Pump of the first fluid path (Filtrate) P4Pump of the second liquid supply means P5Pump of the third means of liquid supply V1Blood inlet channel into thethird connecting chamber V1'Inlet channel of the second liquid supply means in the third connecting chamber V1"Inlet channel for blood in the third connecting chamber from the second connecting chamber V2Outlet channel for blood in the third connecting chamber V3Inlet channel for blood in the first connecting chamber V4Outlet channel for blood in the first connecting chamber V5Inlet channel for dialysate or substitute product (pre-dilution) in the first connecting chamber V5'Outlet channel for dialysate or substitute product (pre-dilution) from the additional distribution chamber (C1.2) to the first connecting chamber V6Outlet channel for dialysate or substitute product (pre-dilution) from the first distribution chamber to the first connecting chamber V6'Outlet channel for dialysate or substitute product from the first distribution chamber to theadditional distribution chamber (C1.2) V7Outlet channel for dialysate or substitute product from the first distribution chamber to the filter V7'Outlet channel for dialysate or substitute product from the first distribution chamber to the additional connection chamber (C1.1) V7"Outlet channel for dialysate or substitute product from the additional connection chamber (C1.1) to the filter V7‴Outlet channel for dialysate or substitute product from the additional distribution chamber (C1.2) to the additional connection chamber (C1.1) V8Outlet channel for dialysate or substitute product (post-dilution) from the first distribution chamber to the second connection chamber V9Inlet channel for dialysate or substitute product in the first distribution chamber V10Outlet channel for blood to the patient V10'Outlet channel for blood to the third connection chamber V10"Outlet channel for blood to a means ofrecovery V11Blood inlet channel into the second connecting chamber from the filter V12Dialysate or substitution product inlet channel (post-dilution) from the first distribution chamber V12'Inlet channel of the third liquid supply means into the second connecting chamber V13Dialysate or substitution product outlet channel V14 and V14'Dialysate or substitution product inlet channel of the first supply means V15Filtrate outlet channel from the second distribution chamber towards the sixth connecting chamber V16Filtrate outlet channel from the second distribution chamber towards the seventh connecting chamber V17Inlet channel into the seventh connecting chamber from the reference volume sensor V18Outlet channel of the volume to be measured V19Inlet channel into the sixth connecting chamber of the volume to be measured (dialysate) V20Inlet channel into the sixthconnecting chamber of the volume to be measured (filtrate) Detailed Description of Disclosure

[0042] In this document, the detailed description of the disclosure includes embodiments of devices, systems and methods presented for illustrative purposes. It is understood that other embodiments are conceivable and may be made without departing from the scope of the invention. The detailed description which follows, therefore, should not be construed in a limiting sense.

[0043] Unless otherwise indicated, the scientific and technical terms used in this document have meanings commonly used by those skilled in the art. The definitions provided in this document are mentioned to facilitate the understanding of frequently used terms and are not intended to limit the scope of the invention.

[0044] Directional indications used in the description and claims, such as "top", "bottom", "left", "right", "upper", "lower", and other directions or orientations are mentioned for the purpose of providing clarity with reference to the figures. These indications are not intended to limit the scope of the invention.

[0045] The verbs “have”, “understand”, “include” or equivalent are used in this document in a broad sense and generally mean “includes, but is not limited to”.

[0046] The term "or" is generally used in a broad sense including "and / or" unless the context clearly indicates otherwise.

[0047] In the present disclosure, a channel may be defined as a hollow, elongated flow conduit for passing a liquid and / or gas from one location to another. It may take the form of a flexible pipe, tubing, or a cavity within a cassette. Some channels have valves that may be preferentially actuated by a linear actuator controlled by a controller to close or open the channel. Without actuation, said valves are preferentially closed. A chamber may be a cavity or channel with multiple inlets and / or outlets, or may take the form of a simple intersection of two channels. Each chamber has an inlet called an inlet channel and an outlet called an outlet channel. Principle of disclosure regarding a blood processing system

[0048] The embodiment shown schematically in the figure 27is a simplified embodiment. The treatment system comprises three pumps (507, 508, 509), three fluid paths and a filtration means or filter (513). The first fluid path runs from the filtration means (513), to the reservoir (517) also called fluid recovery means. The fluid that flows through the first fluid path is called the filtrate. The second fluid path runs from the patient through the filter (513) and returns to the patient (500). The fluid that flows through the second fluid path is the patient's blood. The third fluid path is supplied by a fluid generally called dialysate (but the invention is not limited to this fluid) which flows from the first fluid supply means also called dialysate reservoir (514).The dialysate first flows into the third fluid path and then flows into one or more secondary fluid paths (in diluted or transformed form). The dialysate (or other fluid in the third fluid path) can: . mix with blood: ∘ before the filter (513) to perform a pre-dilution, and / or, after the filter (513) to perform a post-dilution, and / or feed the filter (513).

[0049] To enable these different solutions and therefore perform any dialysis treatment technique, the system requires three chambers (501, 502, 503). The second chamber (502), also called the distribution chamber, is used to direct the dialysate to the filter (513), the first chamber (501) to perform a pre-dilution and / or the second chamber (502) to perform a post-dilution. The first and third chambers (501, 503) may also be called the connection chamber. The first and third chambers (501, 503) are used to mix the dialysate with the blood, in other words, The first and third chambers (501, 503) allow the fluid from the third fluid path to flow into the second fluid path. The channels that connect the chambers to each other or to the filter may include valves (519) and / or a flow restriction or closure means (520).

[0050] There figure 28schematizes a more complex system by adding new optional elements. These could be, for example: of a new supply means (515) which may contain for example an anticoagulant. This fluid may be contained in a reservoir (515) and propelled by a pump (510) or by weightlessness. This supply means may be a syringe, and / or of another supply means (516) which may contain for example an agent inhibiting the anticoagulant. This fluid may be contained in a reservoir (516) and propelled by a pump (512) or by weightlessness. This supply means may be a syringe, and / or A new channel making it possible to connect the third chamber (503) (the one normally used for post-dilution) - or to another chamber (located downstream of the third chamber) - to the first chamber (501) (the one normally used for pre-dilution) - or to another chamber (504) (located upstream of the first chamber) -, this new channel preferably comprises a valve controlled by a controller.It allows the fluid contained in the second fluid path to circulate in a loop so as not to stagnate in the channels, and / or Another channel making it possible to connect the third chamber (503) to the fluid recovery means (517). This channel preferably comprises a valve. It can allow for example the priming of the system or to throw away part of the fluid flowing in the second fluid path, and / or A heating means (522).

[0051] Another embodiment is disclosed by the figure 29. This embodiment may comprise at least one pressure sensor (518) - located in or close to the chambers (504, 501, 502, 503), the filter (513) and / or the supply means (515, 516, 514) - and / or an additional pump (511) (in place of the flow restrictor (520)) in the third fluid path between the distribution chamber (502) and the connection chamber (501). The system may further comprise a calibration system which may comprise a sensor common to the first and third fluid paths. This calibration system comprises two additional channels which allow the fluids contained in the first and third fluid paths to flow towards a sixth chamber (506). This sixth chamber (506) comprises in or connected to it a sensor allowing the calibration of elements (sensors and / or pump) of the first and third chamber so that it is calibrated identically.

[0052] There figure 30discloses a treatment system as described above. This system further comprises a cassette (601) for performing the fluid distribution functions. This cassette (601) is connected to reservoirs (603, 604) and cooperates with a device (602). The device (602) called a dialysis machine may be reusable while the cassette (601) may be disposable. The device (602) may comprise a processor (605), at least one sensor (606) adapted to cooperate with the cassette (601), at least one actuator (607) (for example pump or control means) adapted to cooperate with the cassette (601), a screen (608), at least one acquisition and / or other means such as a battery (609) and / or a memory (610). Methods of producing cassettes according to the operating principle described above

[0053] According to the figure 1the disclosure discloses a system (14) for performing a treatment of a patient's blood and which comprises a blood filtration means (3), at least one liquid supply means (F1), two patient pipes, an outlet pipe (5) withdrawing the blood to be treated and an inlet pipe (6) reinjecting the treated blood to said patient, a filtrate recovery means (F4), at least three fluid pumps (P1, P2, P3), a cassette (2, 2') composed of channels and valves so as to direct the fluids. Said cassette (2, 2') comprises at least one distribution chamber (C1, C1.2, C7) comprising a single inlet channel and at least two outlet channels. Said treatment system (14) comprises a controller which controls the opening and closing of said valves depending on the desired treatment.

[0054] Said treatment system (14) further comprising a first fluid path, connecting said blood filtration means (3) to the filtrate recovery means (F4), composed of a series of channels and a dedicated pump (P3); a second fluid path dedicated to the circulation of blood, comprising a series of channels, said blood filtration means (3), said patient pipes (5, 6) and a dedicated pump (P1); a third fluid path composed of a liquid supply means (F1), at least one dedicated pump (P2), a series of channels, a heating means (4) and at least one distribution chamber (C1, C1.2).

[0055] Advantageously, said distribution chamber (C1) comprises at least three (distinct) outlet channels connected directly or indirectly: to the second fluid path upstream of said blood filtration means (3), to the second fluid path downstream of said blood filtration means (3), to said blood filtration means (3)

[0056] Said cassette may further comprise at least one flow control means adapted to control the quantity of liquid of the third fluid path which flows into at least one of said outlet channels of said distribution chamber (C1). In addition, said at least one flow control means is controlled by said controller which may comprise the processor (605).

[0057] Said cassette (2') can also contain the pumps and / or other elements.

[0058] The treatment system further comprises, in the third fluid path, a flow adjustment means (13, P2') located between said distribution chamber (C1) and said first connection chamber (C2).

[0059] In one embodiment, the third fluid path comprises an additional pump (P2') in the third fluid path, located between the distribution chamber (C1) and said first connection chamber (C2). Said additional pump (P2') plays the total or partial role of flow adjustment means. The purpose of the flow adjustment means is to control the flow of the fluid passing from the distribution chamber (C1) to the connection chamber (C2). The adjustment means thus makes it possible to distribute the quantity of fluid in the connection chamber (C2) and at least one other connection chamber or the blood filtration means (3).

[0060] In one embodiment, one or more flow adjustment means (also called flow restrictor) may be placed between any chamber or element (e.g. blood filtration means (3)). A flow adjustment means (13) may be a pump, a proportional valve and / or a set of channels with dedicated valves and different diameters,... An additional safety valve may be added upstream or downstream of the flow adjustment means (13 - 520). A flow adjustment means allows a flow of 0% to 100% of the fluid at a given time or during a given duration through said flow means. In other words, the flow of a fluid from at least one liquid supply means may be distributed in the different channels according to the needs of the treatment.

[0061] In one embodiment, the treatment system (14) comprises a second liquid supply means (F2 - 515) located on the patient outlet pipe (5) or in the cassette (2, 2' - 601). Said second supply means may contain an anticoagulant such as citrate, heparin, danaparoid sodium or the like.

[0062] In one embodiment, said system (14) comprises a third liquid supply means (F3 - 516) located on the patient inlet pipe (6) or in the cassette (2, 2' - 601). Said liquid supply means may contain calcium or an anticoagulant inhibiting agent.

[0063] On the patient inlet pipe (6) and / or in the cassette (2, 2' - 601), the system comprises at least one safety element (7) for detecting air bubbles in the second fluid path and / or stopping the circulation of blood and / or a means for capturing said air bubbles. Location of the heating means and / or use of two pumps in the third fluid path:

[0064] According to the operating principle disclosed by the figure 31, to be effective, the fluid distribution system (whether for a cassette as described in the present document or for another distribution system) may comprise a precision pump (702), a fluid supply means, a flexible bag (703) and an additional distribution pump (707). The system further comprises a main fluid path (701) which divides into at least two secondary and distinct fluid paths (704, 704'). The precision pump (702) and the flexible bag (703) are positioned in the main fluid path (701), the flexible bag being positioned downstream of said pump. Thus all the pumped fluid is known precisely and can be at least partially stored at least temporarily in the flexible bag. The additional pump (707) is positioned in one of the secondary fluid paths (704). Preferably, the other secondary fluid path (704') comprises a valve (705).In one embodiment, at least one fluid path comprises a pressure sensor (706) positioned downstream of the precision pump (702). Preferably, said pressure sensor (706) is positioned in the secondary fluid path (704) which comprises the additional pump (707) and upstream of the additional pump. Preferably the flexible bag (703) is a heating means.

[0065] Since certain continuous extra-renal purification techniques require heating the dialysate and / or substitution liquid during its injection, said heating means (4) can be located at different points in the third fluid path. In one embodiment, the cassette has a heating means (4) inside the distribution chamber (C1) or upstream of the latter.

[0066] In an embodiment according to the principle described above, the heating means (4) is a flexible pocket, located between the main pump (P2) of said third fluid path and said distribution chamber (C1) which makes it possible to create a constant positive pressure in said pocket (4). The heating pocket is continuously supplied by the pump (P2) which makes it possible, among other things, to guarantee good control of the heating of the liquid of the third fluid path. Said pocket (4) is then directly connected to the inlet channel (V9) of the distribution chamber (C1).

[0067] With this configuration, all the injected liquid passes through a single pump (P2). The pre-dilution pump (P2') (also called the additional pump) only distributes the liquid before and / or after the filter. Thus, only one precision pump is required. Pump (P2) is the precision pump and allows the quantity of fluid pumped to be known. The additional pump simply allows the distribution between the pre-dilution (before the filter) and the post-dilution (after the filter). The pumps are used as follows: If only post-dilution is programmed: the pre-dilution pump (P2') is stopped and all the liquid will be injected after the filter (3). The post-dilution valve (V8) is open. Preferably, the pre-dilution valve (V5) is closed. If only pre-dilution is programmed: the post-dilution pump (P2) delivers the substitution volume. The post-dilution valve (V8) prevents the liquid from passing after the filter. The pre-dilution pump (P2') also regulates the fluid to prevent the pressure in the heating means (4) from becoming negative. If pre- and post-dilution are programmed: the main pump (P2) delivers all the required substitution volume (pre and post). The post-dilution valve (V8) is open. The pre-dilution pump (P2') draws off part of the liquid to inject it before the filter (3).If an accuracy error exists in the pre- and post-injection distribution, its severity is limited because the volume is injected into the patient anyway. Use of the cassette according to the different treatments :

[0068] Slow continuous ultrafiltration (SCUF): There figure 2 represents the use of the cassette applying a slow continuous ultrafiltration treatment. This technique is used to eliminate a liquid overload thanks to the convection principle. Thus, the controller opens only valve V1 of the second fluid path and closes valves V5, V7 and V8 of the third fluid path. Pumps P1 and P3 operate while P2 and P2' do not operate. Continuous venovenous hemofiltration (CVVH): There figure 3represents the use of the cassette applying a continuous veno-venous hemofiltration treatment. This technique is used to obtain the removal of dissolved substances thanks to the convection principle. A substitution solution is injected into the circuit before (pre-dilution) and / or after (post-dilution) the filtration means (3). Thus, the controller opens valves V1 of the second fluid path and V5 and / or V8 of the third fluid path and valve V7 is closed. Pumps P1, P2 (optionally P2') and P3 operate. Continuous veno-venous hemodialysis (CVVHD): There figure 4represents the use of the cassette applying continuous veno-venous hemodialysis treatment. This technique is used to obtain the removal of dissolved substances (small molecules: urea, creatine, K, etc.) and obtain a water balance by diffusion principle. The dialysate is injected into the filtration means (3). Thus, the controller opens valves V1 of the second fluid path and V7 of the third fluid path and valves V5 and V8 remain closed. Pumps P1, P2 and P3 operate. Continuous veno-venous hemodiafiltration (CWHDF): There Figure 5represents the use of the cassette applying a continuous veno-venous hemodiafiltration treatment. This technique is used to obtain the removal of dissolved substances (small or medium molecules) thanks to the principles of diffusion and convection. The dialysate and / or a substitution solution are injected into the filtration means (3) and into the blood after the filtration means (3). Thus, the controller opens the valve V1 of the second fluid path as well as the valves V7 and V8 of the third fluid path. The valve V5 remains closed. The pumps P1, P2 and P3 operate. In this embodiment, the outlet channels V7 and V8 are proportional valves or other means of controlling the flow passing through these valves. In another embodiment set forth in figure 5', the cassette comprises an additional distribution chamber (C1.2) and an additional connection chamber (C1.1). Said additional distribution chamber (C1.2) is directly supplied by the additional pump (P2'). Said additional distribution chamber (C1.2) makes it possible to distribute the dialysate or substitution product either to the first connection chamber (C2) for pre-dilution or to said additional connection chamber (C1.1). Said additional connection chamber (C1.1) is also supplied with dialysate or substitution product by the first distribution chamber (C1) thanks to the outlet channel with a dedicated valve (V7'). Said additional connection chamber (C1.1) also has an outlet channel (V7") which connects to the filter (3).The advantage of such an arrangement is to increase the precision of the quantities injected into the filter and into the second connection chamber for post-dilution or into the filter and into the first connection chamber for pre-dilution. Thus, the additional pump (P2') makes it possible to precisely distribute the quantities of fluid to be distributed. In this embodiment, for a continuous veno-venous hemodiafiltration treatment, the valves V1, V8 and V7" are open. Plasma exchanges (TPE): There figure 6represents the use of the cassette applying a plasma exchange treatment. This technique allows plasma exchanges by membrane filtration. A substitute solution is injected to replace the extracted plasma. Thus, the controller opens valve V1 of the second fluid path as well as valve V8 of the third fluid path. Valves V5 and V7 remain closed. Pumps P1, P2 and P3 operate. Preferably F2 and F3 deliver their fluid into the second fluid path. Hemoperfusion: There figure 7represents the use of the cassette applying hemoperfusion treatment. This technique is used to remove toxic substances from a patient's blood, where the filtration medium contains an absorbent substance. A substitute solution is injected to replace the extracted plasma. Thus, the controller opens valve V1 of the second fluid path as well as valve V8 of the third fluid path. Valves V5 and V7 remain closed. Pumps P1 and P2 operate, pump P3 does not. Preferably, F2 and F3 deliver their fluid into the second fluid path. System with multiple means of liquid supply

[0069] When a fluid path (for example coming from an additional liquid supply means) connects to another fluid path, the cassette preferably comprises a connection chamber allowing the intersection of said two fluid paths.

[0070] In one embodiment described in the figure 8 , the cassette includes: A third connecting chamber (C4) comprising an inlet channel (V1'), a dedicated valve inlet channel (V1) and an outlet channel (V2). This connecting chamber introduces a fluid contained in a second liquid supply means (F2) into the blood fluid path (second fluid path), preferably said second liquid supply means (F2) contains an anticoagulant agent, and / or A third inlet channel (V12') into the second connecting chamber (C3).The third inlet channel (V12') makes it possible to inject a fluid contained in a third liquid supply means (F3) into the blood fluid path (second fluid path), preferably said third liquid supply means (F3) contains an agent inhibiting the anticoagulant, and / or A fourth connection chamber (C5) comprising at least two inlet channels (V14, V14') with a dedicated valve making it possible to have at least two different or similar fluids in the third fluid path, for example dialysate in one bag and a substitution product in another. Uninterrupted circulation, emptying and priming of the second and / or third fluid path :

[0071] In one embodiment described in the figure 9 , the second connection chamber (C3) comprises: An inlet channel (V11) of the second fluid path connected to the filtration means (3) An inlet channel (V12) of the third fluid path connected to the distribution chamber (C1) Three dedicated valve outlet channels (V10, V10', V10"), the first being connected to the patient inlet pipes (6), the second being connected to an inlet channel of the second connection chamber (C4) and the third being connected either to a recovery means (F5), or directly or indirectly to the filtrate recovery means (C6).

[0072] This embodiment allows for example: In the event of a problem, the controller can close valve V10 to avoid, for example, injecting an air bubble or other element into the patient that could endanger the patient's life. In this case, the blood remaining in the cassette and the filter risks clotting. It is therefore imperative that the blood does not stagnate in the cassette or in the filter. Thus, P1 continues to operate, drawing blood from the second connection chamber in order to circulate blood in a loop between the first and second connection chambers and the filter. V10' and / or V1 "are open while V1, V10 and V10" are closed. to take blood samples using valve V10", to initiate treatment by removing air from the system, to rinse the second fluid path with the fluid from the third fluid path, to eliminate all or part of the fluid contained in the second and / or third fluid path. Means and method of calibrating pumps and / or sensors of the first and third fluid path :

[0073] Some continuous extrarenal purification techniques require precise knowledge of the amount of volume injected and withdrawn via the third and first fluid paths, respectively. The treatment system preferably includes peristaltic pumps. This type of pump may experience some inaccuracy. Thus, depending on the figure 10 , to know precisely the quantity of volume added and removed, the distribution system includes at least two volume sensors allowing the volumes of the third and first fluid paths to be measured.

[0074] The first sensor (15) is included in the third fluid path between the distribution chamber (C1) and the main pump (P2) and measures the injected volume from the first liquid supply means (F1, F1'). Preferably, the sensor (15) is located after the heating means (4). The second sensor (17) is placed in the first fluid path downstream of the pump and before any other chamber. Said second sensor (17) measures the volume of the removed filtrate. To avoid any risk of contamination, the two sensors are preferably located in the cassette.

[0075] In a preferred embodiment, the processing system comprises: a third volume sensor (16) for comparing the volumes measured by the two previous volume sensors (15, 17), said sensor is also called a reference sensor, a means for sampling fluids from the first and third fluid path. Said sampling means comprises a sixth connection chamber (C8) having an outlet channel directly connected to said third sensor (16) and two inlet channels (V19, V20) connected respectively to: ∘ a dedicated valve outlet channel (V21) located in the first distribution chamber, ∘ a dedicated valve outlet channel (V15) located in the second distribution chamber optionally, a seventh connection chamber (C9) allowing the reference sensors (16) to reject the measured liquids into the filtrate recovery means (F4).

[0076] To avoid any risk of contamination, said third sensor can preferably be located in the cassette.

[0077] The method includes the following steps: calibration of the injected volume: ∘ opening of the valve (V21) and closing of the other valves, ∘ actuation of the main pump (P2) of the third fluid path, ∘ measurement of the volume pumped by said pump (P2) via said first sensor (15) of said third fluid path, ∘ measurement of said pumped volume via the reference sensor (16), ∘ comparison of the two measurements, ∘ calibration of the first sensor (15) and / or of the pump (P2). calibration of the removed volume: ∘ opening of the valve (V15) and closing of the other valves, ∘ actuation of the pump (P3) of the filtrate of the first fluid path, ∘ measurement of the volume pumped by said pump (P3) via said second sensor (17) of said first fluid path, ∘ measurement of said pumped volume via the reference sensor (16), ∘ comparison of the two measurements, ∘ calibration of the first sensor (15) and / or of the pump (P2).

[0078] These steps can be performed during priming and / or during processing.

[0079] The first and second sensors (15, 17) are adjusted to a common sensor called the reference sensor (16) for optimum relative accuracy. Said sensors, even if inaccurate, are sufficiently effective since they are comparatively (relatively) accurate with respect to the reference sensor (16).

[0080] Said reference sensor (16) may be a scale, a volumetric pump, a mass flow sensor or any sensor making it possible to measure or deduce a volume.

[0081] Preferably, said first and second sensors (15, 17) continuously measure the liquids passing respectively in the third and first fluid path. Thanks to the continuous measurement of the volumes, compensation for any drift is possible. Pressure sensor remote from the fluid path :

[0082] According to the figures 11, 12 and 13, the present invention discloses a fluid delivery system (100) (preferably a cassette as described above) which makes it possible to withdraw and / or deliver a fluid FI1 from and / or to the patient and to measure the pressure of said fluid FI1. The system comprises a rigid body (105) composed of at least one fluid path (103) through which said fluid FI1 flows and at least one channel (102). Said channel (102) is distinct from the fluid path (103) and makes it possible to connect said fluid path to a measurement zone (101). The system further comprises at least one opening (106) covered by a flexible membrane (104) forming said measurement zone. The membrane is shaped to receive a pressure sensor (107).

[0083] A fluid FI2 different from the fluid FI1 is contained in said measuring zone (101). The fluid FI2 extends at least partially into said channel (102). Said fluid FI2 makes it possible to transmit by contact the pressure of the fluid FI1 to said membrane (104). Said channel (102) is a flow restrictor shaped so that said fluid FI1 cannot come into contact with said membrane. The length and / or the shape of said pressure transmission channel (102) depends on the expansion capacity of said fluid FI2 and / or the pressure range to be measured. Preferably, the channel (102) comprises at least one section sufficiently narrow to retain the fluid FI1 so that said fluid does not enter said measuring zone (101).

[0084] In one embodiment, the channel (102) comprises a hydrophobic filter (108) or a membrane.

[0085] In one embodiment, a membrane (104) / fluid (FI3) / sensor cell (107) interface is created to avoid friction of the membrane (104) on said cell which could create disturbances on the measurement. A liquid (FI1) / fluid (FI2) / membrane (104) interface is created to prevent the membrane (104) from being wetted by the liquid (FI1). The transmission of the pressures of FI1 is ensured by the fluids FI2 and FI3, arranged on each side of the membrane (104). FI2 and FI3 preferably have the same physical properties. Preferably, FI2 and FI3 is air. Said membrane (104) can deform with equivalent stresses on each side of these faces and this to compensate for variations in the volume of air, trapped between the membrane (104) and the sensor (107), due to the temperature.

[0086] In another embodiment, the fluid FI1 is aqueous in nature while FI2 is lipid in nature, FI3 being able to be lipid or aqueous in nature.

[0087] In another embodiment, the figure 13'discloses a fluid distribution system (100) that allows the flow of a fluid FI1 and to measure the pressure of said fluid FI1. The system comprises a rigid body (105) composed of at least one fluid path (103) through which said fluid FI1 flows and at least one channel (102). Said channel (102) is distinct from the fluid path (103) but communicates so that the fluid FI1 can flow in the channel (102). Thus, the channel (102) makes it possible to connect said fluid path to a measurement zone (101). The system further comprises at least one opening (106) covered by a flexible membrane (104) forming said measurement zone. Said opening (106) can be of equal or different size than the size of the channel (102). Furthermore, the membrane is shaped to receive a pressure sensor (107). A fluid FI2 different from the fluid FI1 is contained in said measuring zone (101).The fluid FI2 is contained at least in part in the measuring zone and / or in the channel (102).

[0088] In an embodiment still illustrated by the figure 13' , the quantity and / or the volume of the fluid FI2 is constant or can decrease over time so that the fluid FI1 progresses more or less quickly in the channel (102) and / or the measurement zone (101).

[0089] In one embodiment, the measuring area (101) and / or the channel (102) at least partially contain the fluid FI2 and the fluid FI1. The fluid FI1 may partially wet or be in contact with the membrane (104). The length and / or shape of said pressure transmission channel (102) depends on the expansion capacity of said fluid FI2 and / or the pressure range to be measured.

[0090] The channel (102) may be shaped so as to limit and / or slow down the progression of the fluid FI1, for example during use of said system. The fluid distribution system (100) may be adapted so as to ensure that the membrane (104) and / or the measuring zone (101) are not completely wetted by or in contact with the fluid FI1 during use of said system. Energy-saving linear actuator :

[0091] The disclosure discloses a linear actuator (200) using a motor (for example a direct current motor (also called DC motor) or other type of motor known to those skilled in the art) (201) coupled to interposed means making it possible to transform the rotation of the motor axis into a linear movement. Preferably, the motor may also comprise a torque reducer.

[0092] In particular, the means interposed include: at least one peripheral ramp (214) arranged inside a piston (207), at least one support means (209) fixed directly or indirectly to the rotor (208) of said electric motor (201), said support means (209) being shaped so as to cooperate with said peripheral ramp (214), at least one guide means (203, 216) allowing the piston (207) to guide the translational movement.

[0093] Said ramp (214) comprises at least one threshold, of which a threshold (215) is located at the top of said ramp (214). In one embodiment, at least one threshold may be shaped so as to cooperate with the support means. For example, the threshold may be perfectly flat, horizontal with respect to the vertical movement of the piston. The threshold may also have a specific shape to ensure good support of the support means in order to guarantee the maintenance of the position, for example, the right embodiment of the figure 18'. Furthermore, the threshold (215) located at the top of said ramp (214) can be followed by a passage (219) allowing the piston (207) to free itself from the constraints exerted by said support means (209).

[0094] The piston may comprise one or more ramps and / or one or more passages. At least one ramp may have an inclination between 0 and 90°. In one embodiment, said inclination may be between 0 and 45°, preferably between 10 and 30°.

[0095] Said piston (207) comprises at least two stationary positions: a first position where the piston (207) is located at a distance (d2) equal to A. In this position, the support means (209) is at the start of the ramp. a second position where the piston (207) is located at a distance (d2) equal to B. In this position, the support means (209) cooperates with a threshold allowing the piston to remain in this position.

[0096] The system has several advantages: No need to power the motor to keep the valve open (3rd stable state). The actuator will not heat up when it maintains a position. Low operating noise. Long stroke.

[0097] In a preferred embodiment as shown in the figure 16 , the piston (207) has at least one ramp (214) (preferably two or more) and the support means may be a transverse axis adapted to cooperate at least temporarily with said at least one ramp.

[0098] Also, when the piston comprises two ramps positioned symmetrically with respect to the center of the rotor axis, for a complete revolution of the rotor, the piston can be twice in the second position and first position. The piston can comprise a passage (219) allowing a rapid transition from the second position to the first position, said passage can extend below the first position. This allows: to obtain two piston positions (first and third position) without actuating the actuator, facilitate assembly, prevent the rotor (or motor) from rotating when the piston is in the third position, making it impossible to change position when the cassette is not loaded in the device.

[0099] According to one embodiment, the ramp is followed by at least one passage, preferably after a threshold.

[0100] In one embodiment, said actuator further comprises at least one compression means (205) which exert a force against the piston (207). The support means and the ramp cooperate in order to move the piston along the same axis as the force exerted by the compression means but in the opposite direction.

[0101] In one embodiment, said compression means tends to push the piston (relative to the actuator) (i.e., in the direction (220) of the distal end of the piston (217)) while the support means and the ramp force the piston to move closer to the actuator. In this case, A > B. In another embodiment, said compression means tends to move the piston closer to the actuator while the support means and the ramp force the piston to move away from the actuator. In this case, A < B.

[0102] In one embodiment, the actuator is intended to drive an element of a device as described in this document. This may be, for example, a valve of the cassette. The remainder of the description describes this embodiment, but it goes without saying that the invention is not limited to this embodiment.

[0103] Thus, said piston (207) comprises at least two positions: a first position where the nipple (211) of the piston (207) is coupled to the valve (212) (illustration in figure 15) of a cassette as previously described. The piston (207) not being constrained by the support means (209), maintains the valve (212) in the closed position against the valve seat (213). Here, d2 is equal to A. a second position where the stud (211) of the piston (207) is coupled to the valve (212). The piston (207) is constrained by the support means (209), moving the piston / stud assembly in the direction (221) of the motor (201). When said support means (209) reaches the threshold (215) located at the top of the ramp, the piston (207) is in the second position and the valve (212) in the open position. Here, d2 is equal to B.

[0104] In one embodiment, the piston has a third position, where the nipple (211) of the piston (207) is decoupled from the valve (212). A compression means (205) exerts a force against the piston, moving said piston to a third position further from the engine than the first and second positions. This may be the same compression means described above or a separate compression means. Here, d2 is equal to C. In this embodiment C > A > B. The advantage of this third position is to guarantee sufficient occlusion pressure when the piston is coupled to the valve in the first position. In other words, when the piston is coupled to the valve, the piston exerts a force against the valve in order to ensure the closure of the valve when the piston is in the first position.

[0105] In one embodiment, the actuator comprises a fixing element to its support comprising a compression means exerting a force towards the distal end of the piston and having the same function described above.

[0106] Said compression means (205) may be a spring, an elastic blade, an elastic or a shape memory material. Said compression means (205) may exert a force of 0 to 6N, preferably between 5 and 6N.

[0107] The actuator (200) is designed to not consume energy when maintaining a stationary position. The support means (209) is designed to slide or roll on the ramp to reach a position. When the support means (209) stops on a threshold, said threshold is shaped so that the assembly is in equilibrium. The threshold (215) at the top of the ramp (214) is directly followed by a passage (219) allowing the piston to quickly move from a second position to a first position while consuming a minimum of energy. Said passage allows moving from one position to the other with a small amount of energy. In other words, the energy consumed by the actuator to move from the first position to the second position is greater than the energy consumed by the actuator to move from the second position to the first position. The passage (219) may be a ramp having a high slope and / or in the opposite direction to the slope of the ramp.Thus, the support means travels a shorter distance to move from the second position to the first than vice versa.

[0108] Optionally, the piston (207) includes several thresholds in order to have intermediate rest positions.

[0109] In one embodiment, the motor comprises a torque reducer between the motor and the rotor of the interposed means. Said torque reducer can be designed so that the motor can rotate the rotor but the rotor cannot rotate the motor. In other words, the torque reducer can, thanks to its design, prevent or limit or brake any movement of the rotor which is not caused by the motor.

[0110] In one embodiment, the torque reducer may be designed so that the actuator can maintain any position when the motor is stopped (powered or not). Thus, the actuator may include a limited number of thresholds as described above but an unlimited number of positions that can be maintained by the torque reducer without the actuator being powered. Such an actuator may be adapted to cooperate with a proportional valve of a fluid distribution cassette. Thus, thanks to this design, the actuator can allow the flow of a fluid proportionally to the need for the treatment.

[0111] In one embodiment, the piston (207) does not include any threshold but only positions that can be maintained using the torque reducer as described previously. This piston thus includes at least one ramp and optionally a passage. The torque reducer allows the actuator to maintain a given position allowing the opening from 0% to 100% of a valve (for example a proportional valve).

[0112] In one embodiment, the piston comprises at least one lower ramp and one upper ramp. Said ramps are adapted so that at least one support means (209) can move between said ramps. Said ramps can at least partly be parallel to each other.

[0113] In a preferred embodiment, at least one actuator is included in an actuation system that comprises a controller and at least one power supply means. Said system is designed to move at least one piston from a second position to a first position and vice versa while consuming a small amount of energy. Said power supply means may be an external power supply and / or an energy storage means. Said energy storage means may be used by the system when said external power supply is no longer operative or insufficient. Thus, in the event of a power failure, the valve will switch from the open state to the closed state thanks to the use of said energy storage means which may be a supercapacitor or a battery.

[0114] According to an embodiment disclosed by the figure 14 , the actuator (200) can be composed of: of a motor (201) of a rigid casing (202), inside which is arranged: ∘ a sensor (204) fixed to the motor with said casing (202), ∘ a compression means (205), ∘ a piston (207) in which is fixed an element (206) adapted to cooperate with said sensor (204), ∘ a support means (209) fixed directly or indirectly to the rotor (208) of the motor (201), ∘ an element (210) fixed on the distal end (217) of the piston makes it possible to fix a nipple (211) which will be coupled to a valve.

[0115] The piston (207) and the rigid casing (202) comprise guide means (203, 216) in order to prevent the piston from rotating with the rotor (208) of the engine.

[0116] THE figures 17, 18, 19 , 20 and 21 show the piston in different positions (the valve and nipple are not shown in these figures): ∘ Figure 17, the valve is not coupled to the nipple. The piston (207) is in third position with the compression means (205) relaxed. The support means (209) is in the passage (219) and does not exert any force against the ramp (214). ∘ Figure 18 , the valve is coupled to the nipple. The piston (207) is in the first position, the compression means (205) exerts pressure against the piston (207) in order to guarantee the closed position of the valve. Preferably, the support means (209) and the ramp (214) do not exert any constraint. The figure 18' allows two distinct embodiments of the threshold (215) at the top of the ramp to be highlighted. Thus, according to one embodiment, said threshold can have a different shape, it can be flat or more or less shaped for greater cooperation with the support means (209) when the latter is located near and / or on the threshold (215). ∘ Figure 19, the valve is coupled to the nipple. The rotor (208) is in motion to allow the piston (207) to move from the first position to the second position. The support means (209) runs on the ramp (214) and forces the piston (207) to move closer to the motor (opening of the valve) and compresses the compression means (205). ∘ Figure 20 , the valve is coupled to the nipple. The piston (207) is in the second position, the support means (209) stops on the threshold (215) at the top of the ramp. The compression means (205) is compressed. The valve is open. The position is stable without contribution from the motor (201). In one embodiment, the actuator comprises a sensor designed to know the relative position of the piston (207). The embodiment exposed through the figure 20discloses a Hall effect sensor (204) cooperating with a magnet (206) housed in the piston. The sensor (204) may be a linear displacement sensor comprising a rod or an encoder or any elements (206) being adapted to cooperate with said sensor (204). In addition, thanks to the processor connected to the sensor (204), it is possible to know or control the position of said piston (207). ∘ Figure 21 , the valve is coupled to the nipple. The rotor (208) is in motion, causing the support means (209) to pass into the passage (219). The piston instantly moves from the second position to the first position thanks to the compression means (205) which pushes the piston (207) towards the distal end of the piston (217). The valve closes. Actuator control and monitoring system

[0117] In one embodiment disclosed by the figures 32, 32' and 33, a control system (800) comprises a linear actuator comprising a movable part (801) and a fixed part (804) as well as control and command elements (802, 803, 805). The control and command elements are adapted to know the position of the movable part (801) relative to the fixed part (804) and to control the linear actuator.

[0118] There figure 32 exposes the actuator in a position A and the figure 32'exposes the actuator in a position B. The control element (805) controls the actuator whose fixed part (804) may comprise the drive means (for example a motor). The movable part (801) may be adapted to cooperate with, for example, a valve of a fluid distribution system. Thus, position A could correspond to the closed position of the valve to be controlled and position B could correspond to the open position of said valve, however the invention is not limited to the control of opening and closing of a valve of a fluid distribution system and the number of positions may be limited or unlimited.

[0119] Elements 1 (802) and 2 (803) of the sensor are designed to cooperate and determine at least one position. It can be a capacitive or inductive displacement sensor (LVDT, ...), an electromagnetic sensor (Hall effect sensor), an ultrasonic, infrared, optical, laser, mechanical or microwave sensor (non-limiting list). In our example and to facilitate understanding, we will use a Hall effect sensor. Thus, element 1 (802) is a permanent magnet (in this case, it is not connected to the processor) (805) and element 2 (803) is a Hall effect sensor connected to the processor. The permanent magnet creates an electromagnetic field whose intensity the sensor (803) measures. In particular, the sensor (803) makes it possible to detect the variation of the magnetic field induced by the permanent magnet (802) when it moves.

[0120] Preferably, the permanent magnet (802) is rigidly fixed in a permanent manner to the movable part (801) of the actuator and the sensor (803) is rigidly fixed in a permanent manner to the fixed part (8004) of the actuator (or vice versa). Thus, when the movable part moves the permanent magnet (802) moves closer to or further away from the sensor (803) which thus measures a variation in the intensity of the magnetic field of the permanent magnet (802). Ideally, the magnet and the sensor are aligned.

[0121] The measurement data from the sensor (802) are transmitted to the processor to process the signal. Normally, all control systems must be qualified in order to determine in advance the intensity corresponding to each position. In other words, generally, the sensor detects predetermined value thresholds corresponding to respective positions determined in advance. However, this qualification work (for example calibration which must be carried out on all actuators) is long and expensive. In order to avoid this qualification work, the invention discloses the use of a processor which performs signal processing to determine at least one position of the actuator. Thus, the invention makes it possible, for example, to avoid performing calibration.

[0122] The top graph of the figure 33allows us to highlight that the absolute value (the intensity of the electromagnetic field of the magnet measured by the sensor) can be very different from one actuator to another. Indeed, the sensors of actuators 1 and 2 do not record the same intensity (in absolute value) even though their position is identical. Thus, it would be difficult and unreliable, if not impossible, to determine the position of these actuators based on a single threshold value.

[0123] The control system (800) comprises a processor (805) which uses a mathematical model taking into account the derivative of the absolute value. In this document, the absolute value is the value measured by the sensor (803), it corresponds to the intensity of the magnetic field. The curve of the absolute value is represented by the upper graph of the figure 33. The derivative of the absolute value is the slope of the curve drawn by the absolute value. In other words, the derivative allows us to know the slope of the variation of the magnetic field when the magnet moves relative to the sensor. This derivative is represented by the curve of the graph in the middle of the figure 33 . Thus, this derivative makes it possible to know the direction of movement of the mobile part (801) of the actuator relative to its fixed part (804).

[0124] The control system thus comprises a processor using a mathematical model that takes into account the derivative of the signal. Thanks to this mathematical model, it is possible to know when the actuator has reached a position or a threshold as described in the chapter disclosing the linear actuator. Indeed, when the actuator moves its movable part (801) the first derivative is greater than or less than 0 but when the actuator does not move its movable part (801), its first derivative is substantially equal to 0. In our example and preferably, when the magnet (802) moves away from the sensor (803) the first derivative is negative and conversely when the magnet moves closer, the first derivative is positive.

[0125] The system may further include a mathematical model to determine when the moving part is moving and when it is stationary. This second mathematical model takes into account the second derivative of the absolute value. Using this second mathematical model, the system knows when the moving part changes its behavior (moving or stationary).

[0126] In one embodiment, the control system comprises an actuator comprising at least one ramp and at least one threshold (e.g., a linear actuator as described herein), a processor adapted to control the actuator and to process the signal according to at least one mathematical model.

[0127] A first mathematical model takes into account the first derivative of the absolute value measured by the sensor (803). The processor can use this first mathematical model to know in which direction the moving part (801) is moving. When the first derivative is close to 0, the control system knows that the actuator has reached a threshold.

[0128] A second mathematical model takes into account the second derivative of the absolute value measured by the sensor (803). The processor can use the second mathematical model to know when a threshold is reached and / or when the moving part is stationary or moving. The lower graph of the figure 33represents the signal resulting from the second mathematical model. When the signal is equal to the value f, this means that the actuator maintains a position or is on a threshold. When the signal is equal to the value d, it means that the mobile part (801) is moving. Thus, thanks to this second mathematical model, the system does not need the absolute value. When the control system powers the actuator to move its mobile part (801), the second mathematical model makes it possible to know when the actuator has reached a position. In other words, when the actuator continues its actuation (for example, it rotates the support means (209)) but the mobile part no longer moves, thanks to the first and / or second derivative, the processor is able to know that the support means has reached a threshold.So, when the processor orders the actuator to change position, a mathematical model allows the processor to know when the threshold is reached and thus orders the actuator to stop.

[0129] Thus, said control system is adapted to determine at least one position reached by the movable part (801) of the actuator independently of the characteristics of the sensor used. Said control system is adapted to control the stopping of the actuator at at least one position reached by the movable part (801) of the actuator independently of the characteristics of the sensor used.

[0130] In one embodiment, the control system comprises an actuator comprising at least two distinct positions. The actuator comprises at least one threshold defining a position and at least one ramp for changing position. The actuator is driven by a motor designed to rotate preferentially in a single direction so that it passes from one position to another sequentially and in a pre-established order. Preferably, the actuator is adapted to return to its starting position by performing at least one partial revolution. Furthermore, the processor comprises a mathematical model which takes into account the second derivative of the absolute value measured by said sensor. Said processor comprises a memory which contains the sequence of positions so that said system does not need to know the first derivative of the absolute value to know the position of the actuator.The actuator only needs to make one revolution to know its precise position, for example, when starting the system. Drive device used for peristaltic pumps :

[0131] In one embodiment, the treatment system may include a drive device used for peristaltic pumps. Said drive device disclosed herein may also be used by various peristaltic pumps and / or fluid delivery systems comprising a peristaltic pump.

[0132] The invention discloses a means of correcting tolerance errors of the shaft driving peristaltic pumps. Said invention, presented in Figure 22 and 23, is a drive device (300) which comprises a floating shaft (301) driven by a drive means (303) fixed to a rotor (310) of an electric motor (not shown). Said floating shaft (301) comprises a base (311) / cover (302) integral assembly enclosing a cavity inside which said drive means (303) is at least partially circumscribed. Said drive means (303) comprises a rigid body shaped so as to cooperate with the walls (309, 309') of said cavity (313) in order to allow restricted freedom of the floating shaft (301) relative to the axis of said rotor (310). A screw (307) can make it possible to fix the drive means (303) to said rotor (310).

[0133] The cavity comprises at least one cooperation element (312) which allows said drive means (303) to transmit a rotational movement to said floating axis. Preferably, said cooperation element (312) is an opening bounded by two hard elements (308) and through which an axis (306) is housed perpendicularly. The space between the two hard elements (308) is reasonably greater than the diameter of the axis (306).

[0134] The hard elements (308) and / or the shaft (306) may be made from hard metals such as cobalt, tungsten, vanadium, chromium, manganese, nickel, titanium, germanium, gallium, bismuth, iridium, lithium, magnesium, molybdenum, strontium, rubidium, or palladium. In one embodiment, the hard elements (308) have a greater hardness than the shaft (306). The hard elements (308) and / or the shaft (306) may be treated to increase their hardness, for example, zirconium oxide or one of its alloys.

[0135] In one embodiment, the body (304) of said drive means (303) may be of perfectly round or partially flattened spherical shape. In another embodiment, said body (304) forms a roller comprising three faces. Two of the three faces oppose each other and are connected to each other via the third face which is curved. According to the XZ plane, said roller forms a circle formed by said curved face. The connection between at least one of the two opposing faces with the curved face may be rounded according to the XY plane. The opposing faces may be substantially flat and / or substantially parallel to each other.

[0136] In one embodiment, the cavity (313) comprises smooth walls (309, 309'). Preferably, the upper wall (309) and / or the lower wall (309') of said cavity (313) are at least partially conical in shape. The surfaces of the upper (309) and lower (309') walls may be flat or curved.

[0137] In an embodiment, along the XY plane, the cone of the smooth wall (309) is defined at an angle between 0 and 90°, preferably between 5 and 30°. The cone of the opposite smooth wall (309') is defined at an angle between -0 and -90°, preferably between -5 and -30°. The angles of the two partial cones may be equal or different.

[0138] The smooth walls (309, 309') are adapted to cooperate with the ends of the body (304) so ​​that the floating axis (301) can move along at least three axes X, Y or Z and / or undergo pitching movements. For example, along the Y axis, the floating axis (301) can undergo a pitching movement of + / - 10°, preferably less than + / - 5°.

[0139] In one embodiment, the drive means (303) comprises a longitudinal axis (305) and the floating axis (301) comprises a second cavity (313') which extends along the floating axis. The longitudinal axis (305) fits within the second cavity (313') to restrict pitching movements of the floating axis (301).

[0140] Generally and preferably, the dimensions of the elements forming the drive means (303, 306, 305) are reasonably smaller than the elements forming the interior of the floating axis (301, 302, 313, 312).

[0141] In one embodiment, the drive system (300) comprises a drive shaft formed from a single piece which extends along the Y axis and which is adapted to drive at least one roller (320) of a peristaltic pump system. Said roller is adapted to crush a flexible tube (not shown) against a wall (not shown). According to the figures 22 and 23 , the drive shaft is represented by the floating shaft (301). In other words, the drive shaft may be the floating shaft and / or merged with a part of the drive system. Depending on the figures 22 and 23 , the drive shaft may be cylindrical in shape and include a beveled free end (here the term free end is opposed to the opposite end which is linked directly or indirectly to the motor). The cylinder of the drive shaft forms a circle along an XZ plane.

[0142] In one embodiment, said drive shaft is formed from a single piece composed of at least two different cylinders defined by the same axis (in other words the center of the cylinder) but having different diameters. Thus, along the XZ plane, the drive shaft can form at least two parallel circles but of different sizes. Furthermore, the drive shaft can comprise three cylinders, only one of which is of different diameter. The cylinder defined by the smallest diameter can be arranged between the two cylinders of equal diameter. Said larger diameter cylinders can have treated surfaces so as to improve cooperation with the rollers of the peristaltic pump.

[0143] This construction of the three-cylinder drive shaft is particularly suitable and advantageous for the use of an H-shaped roller, such as the roller (320) of the figure 23. The roller is included in a peristaltic pump system and crushes a flexible hose. The crushing function is preferably performed by a rigid part (322) of the roller (320). Said roller (320) is a cylinder forming a circle on the XZ plane and comprises an axis (321) at the center of this cylinder which extends along the Y axis, a rigid part (322) and at least one flexible part (323) which is deformable. The flexible part is adapted to cooperate with the drive axis.

[0144] Preferably, the larger diameter cylinders come into contact with the flexible parts (323) of the roller (320) and drive the roller (320). When the drive shaft is in contact with at least one flexible part, said flexible part (323) can deform in order to improve cooperation between these two elements and / or to adjust the tolerance errors of each of the elements. Preferably, the roller comprises a rigid part (322) in its center and two flexible parts (323) at the ends along the Y axis.

[0145] A fluid distribution system comprising a floating shaft (301), a three-cylinder drive shaft and / or a roller with rigid and flexible parts makes it possible to substantially improve the roller / drive shaft cooperation and to correct the tolerance errors of the various elements of the system. Means of damping pressure peaks :

[0146] In one embodiment, the treatment system comprises at least one means for damping pressure peaks.

[0147] There figure 24 shows the pressure signal measured near the inlet of a peristaltic pump. On the first curve (401), it is possible to observe the oscillation of the pressure while the second curve (402) represents the average value of this pressure. The objective of the damper is to reduce the amplitude of the oscillations of the first curve (401).

[0148] Such a damping means may be installed in one or more fluid paths of a distribution system as described above. Preferably, this damping means is integrated into a cassette.

[0149] Whether in peritoneal dialysis or continuous extra-renal purification therapy, each treatment has one or more possible configurations. However, the phenomenon of pressure peaks can be amplified or attenuated by various elements that vary according to said configurations. As a reminder, one of the objectives of the invention is to allow simple use of the system. Reproducibility is therefore an important element because the operator (generally the nurse) must be able to ensure the proper functioning of the system without having to take into account the characteristics of the different elements.

[0150] The delivery system as disclosed in this document is a cassette through which fluids flow in three fluid paths. Preferably, these fluids are propelled by peristaltic pumps. Reproducibility, precision and patient comfort are important elements. Thus, preferably, at least one damping means is integrated into said cassette. To be as effective as possible, said damping means must be placed as close as possible to the pumping system.

[0151] In an embodiment shown schematically in figure 25, the fluid path comprises walls (404) delimiting said path. These walls may be the rigid walls of the cassette. A section of the fluid path is covered with a flexible membrane (403) which then replaces said wall (404). Thanks to the elasticity of said flexible membrane (403), the pressure peaks are substantially attenuated, absorbed by the deformation of the membrane (403). The absorption of these peaks is a function of the size and elastic characteristics of the membrane.

[0152] In another embodiment shown schematically in figure 26, the fluid path also includes walls delimiting said path but a section is replaced by a cavity filled with a compressible fluid such as air. This air may have been trapped (approximately 1mL) during the priming of the system. Thus, the volume of air is more or less compressed during pumping, absorbing the energy of the pressure peaks. This embodiment is particularly efficient because it requires little energy for its operation and said fluid absorbs pressure peaks very quickly. Preferably, the cavity or the inlet of the cavity is designed to prevent the compressible fluid from escaping completely. In other words, the cavity is designed to prevent the flowing fluid from replacing the compressible fluid.

[0153] Preferably, said damping means is placed upstream of the pumping mechanism.

Claims

1. Drive device for a peristaltic pump of a medical device, comprising: - a drive means (303) fixed to a rotor (310) of a motor, and - a floating shaft (301) having an axis of rotation driven by the drive means (303); wherein the floating shaft (301) comprises an integral assembly of base (311) and cover (302), forming a cavity (313) within which the drive means (303) is at least partially circumscribed, wherein said drive means (303) comprises a rigid body (304) shaped in such a way as to cooperate with internal walls (309, 309') of said cavity (313) in order to permit a limited freedom of the axis of rotation of the floating shaft (301) with respect to the axis of said rotor (310) so as to relax the manufacturing tolerances of the peristaltic pump.

2. Device according to Claim 1, wherein said cavity (313) comprises at least one cooperation element (312) configured to allow the drive means (303) to exert a rotational movement on said floating shaft (301).

3. Device according to Claim 2, wherein the drive means (303) comprises a transverse shaft (306) configured to engage the cooperation element (312) in such a way as to apply a rotational movement to the floating shaft (310).

4. Device according to Claim 2, wherein the cooperation element (312) is made of a composition comprising an element from the following list: cobalt, tungsten, vanadium, chromium, manganese, nickel, titanium, germanium, gallium, bismuth, iridium, lithium, magnesium, molybdenum, strontium, rubidium and palladium.

5. Device according to Claim 3, wherein the transverse shaft (306) is made of a composition comprising an element from the following list: cobalt, tungsten, vanadium, chromium, manganese, nickel, titanium, germanium, gallium, bismuth, iridium, lithium, magnesium, molybdenum, strontium, rubidium and palladium.

6. Device according to any one of the preceding claims, wherein the body of said drive means (303) comprises smooth rounded edges and the cavity (313) comprises smooth walls.

7. Device according to any one of the preceding claims, wherein the internal walls of said cavity are of conical shape.

8. Device according to any one of the preceding claims, wherein the drive means (303) comprises a longitudinal shaft (305), and the floating shaft (301) comprises a second cavity (313') which extends along the floating shaft (301).

9. Device according to Claim 8, wherein the longitudinal shaft (305) is configured to fit within the second cavity (313') in order to limit the lateral movements of the floating shaft (301).

10. Device according to any one of the preceding claims, wherein the dimensions of the elements forming the drive means (303) are at least smaller than the inner elements of the floating shaft (301).

11. Device according to any one of the preceding claims, wherein the internal walls (309, 309') of the cavity (313) are configured to cooperate with walls of the drive means (303) in order to allow the floating shaft (301) to move linearly with respect to the drive means (303).

12. Device according to any one of the preceding claims, wherein the internal walls (309, 309') of the cavity (313) are configured to cooperate with walls of the drive means (303) in order to allow the axis of rotation of the floating shaft (301) to undergo pitching movements with respect to the motor axis of between + / - 10° or + / - 5°.

13. Medical pump system, comprising: - a peristaltic pump; and - a drive device according to Claim 1, configured to cooperate with the peristaltic pump.

14. Device according to Claim 13, wherein the peristaltic pump comprises at least one roller and a flexible tube.