IMPROVED PUMPING DEVICE

Description

[0001] The present invention relates to the field of syringe pumps, in particular precision pumps intended for dosing small volumes: See US2019 / 234399 A1, which discloses a system according to the state of the art.

[0002] Accurate dosing, especially for medications, can be vital. However, pumps can lose their accuracy as they age. Leaks can develop, for example, in the syringe plunger seals or where the syringe connects to a fluid supply or outlet pipe. Play can develop or worsen between various pump components. Blockages or obstructions can also prevent the pump from operating properly.

[0003] The aim of the invention is to propose a pump equipped with means for monitoring its operation, and guaranteeing more precise dosing than in the pumps of the prior art.

[0004] According to a first object of the invention, a system for actuating a piston of a syringe in a syringe pump, the piston being provided with a connector, comprises: an engine; transmission means; and, a pusher; the transmission means being provided to transmit an action from the motor to the pusher and the pusher being provided to move the piston in translation along a syringe axis, the pusher comprising: a socket for the connector; a fixing segment provided to be fixed to the transmission means; a beam which connects the socket to the fixing segment, transversely to the syringe axis; and, a sensor for measuring a bending of the beam around an axis perpendicular to the syringe axis.

[0005] The motor is preferably a rotary motor, a shaft of which forms a screw, the transmission means comprising a nut screwed onto the screw and a bracket linked in translation with this nut, the fixing segment of the pusher being fixed to the bracket. The motor is advantageously a stepper motor.

[0006] The sensor can be a strain gauge glued to one face of the beam.

[0007] Advantageously, the socket and the connector form a linear-annular connection between them. The connector may comprise a sphere formed at one end of an axial rod of the piston and the socket may comprise a cylindrical groove and a slot, the groove being provided to house the sphere therein, extending along an axis substantially perpendicular to the syringe axis and having a diameter substantially equal to a diameter of the sphere, and the slot being provided for the passage with play of the rod when the sphere is in the groove. The groove may comprise an axial opening for introducing the connector therein.

[0008] According to a second object of the invention, a precision pump comprises a system according to the first object of the invention. It preferably comprises gripping means for removably mounting a syringe according to the second object of the invention.

[0009] Such a pump advantageously comprises at least one sensor from among a current sensor for the motor, an ambient air pressure sensor, an ambient temperature sensor, a vibration sensor, an infrared sensor, an ultrasonic sensor and a humidity sensor. It may also comprise remote control means and means for transmitting data recorded by the flexion sensor and, where appropriate, one or more other sensors to the remote control means.

[0010] According to a third object of the invention, a method for monitoring wear of a syringe in a pump according to the third object of the invention uses data recorded by the bending sensor and, where appropriate, one or more other sensors. Preferably, this method comprises a prior learning step.

[0011] Several embodiments of the invention will be described below, by way of non-limiting examples, with reference to the appended drawings in which: [ Fig. 1 ] is a schematic perspective view, three-quarter front left, of a syringe pump according to the invention; [ Fig. 2 ] is a schematic view in longitudinal section and elevation of the pump of the figure 1 ; [ Fig. 3 ] is a schematic longitudinal elevation view of the front part of the pump of the figure 1 , in the vicinity of the syringe; [ Fig. 4 ] is a schematic perspective view, three-quarter front right, of a plunger for the syringe of the figure 3 ; [ Fig. 5 ] is a schematic view, in elevation and from the front, of a detail of the means of actuation of the syringe; and, [ Fig. 6 ] is a schematic perspective view, three-quarter front right, similar to that of the figure 4 , illustrating another embodiment of a pusher usable in the pump of the figure 1 .

[0012] There figure 1 represents a precision pump 1 according to the invention. This pump comprises and uses a syringe 2. It further comprises: a frame 3; a valve 4; means 6 for actuating the syringe; a valve motor 7 for actuating the valve 4; and, electronic control means 8.

[0013] The actuating means 6 of the syringe comprise a syringe motor 10, transmission means 11 and a pusher 12.

[0014] The syringe is substantially of revolution around a syringe axis X2. In the example illustrated, the syringe axis is vertical. As particularly illustrated in the figure 3 , the syringe 2 comprises a cylinder 13, a piston 14 movable through an axial opening 15 of the cylinder, and an axial fluidic socket 16. The fluidic socket 16 is a male socket, formed outside the cylinder, opposite the opening 15 in a bottom 17 of the cylinder. The syringe further comprises an axial channel 18 which allows circulation of a fluid between a chamber 19 of the cylinder and the outside of the syringe, through the bottom 17 and the fluidic socket 16. The chamber 19 is defined between the cylinder and the piston; its internal volume varies depending on the position of the piston in the cylinder.

[0015] In the illustrated example, the piston 14 comprises a head 21, mounted to slide in a sealed manner in the cylinder 13, a rod 22 which extends axially from the head to the outside of the cylinder, and a connector 23 formed at one end of the rod opposite the head 21. The head comprises an annular seal 21A, to provide a seal between the piston 14 and the cylinder 13. In the illustrated example, the connector 23 has the shape of a sphere 23 mounted on a portion 22B of reduced section of the rod 22. The rod and its portion of reduced section each have a circular section, around the syringe axis X2. The portion of reduced section has a constant diameter denoted D22B. The sphere 23 has a diameter denoted D23.

[0016] Valve 4 is a rotary valve about a valve axis X4. It is actuated by valve motor 7. It has three ports 46-48. In the illustrated example, the three ports are female fluid ports. A first female fluid port 46 is designed to connect with the male fluid port 16 of the syringe. It also includes a second female fluid port 47 and a third female fluid port 48, each for connecting a tube. For example, one tube can be connected to a reservoir to pump the fluid, and another tube to dispense a desired volume of the pumped fluid. Rotating the valve connects the first port 46 to either the second port 47 or the third port 48.

[0017] The chassis 3 is made by injection, from aluminum. It has the shape of an “L”. It comprises a base 25 in the form of a substantially rectangular plate and elongated from front to rear. It also comprises a substantially vertical upright 26 which extends upwards from a front end of the base 25.

[0018] The syringe motor 10 is attached to a rear end of the base 24. It comprises a vertically arranged shaft 28 forming a screw. The transmission means 11 include a drive nut 29 and a boom 31. The nut 29 meshes with the screw 28. The boom extends from rear to front; it meshes with the nut 29 at its rear end 31A and with a linear guide 32 at its front end 31B. The guide 32 is attached to the upright 26 of the frame 3. The nut drives the boom 31 vertically, and the guide 32 maintains the boom's vertical translation.

[0019] A linear encoder is fixed to the frame 3, and a graduated ruler is fixed to the bracket 31, opposite the linear encoder. The movement of the graduated ruler is read by a linear encoder. The linear encoder-ruler pair makes it possible to verify with great precision that a movement is taking place and makes it possible to determine a substantially absolute position of the piston relative to the frame.

[0020] The pusher 12 is fixed to the front end 31B of the stem 31. As particularly illustrated in the figure 4 , the pusher 12 has the shape of an “L”, the upright of which is referenced 34 and the base of which is referenced 37. The upright 34 of the “L” serves as a segment for fixing the pusher to the bracket; it is pressed against a vertical front face of the front end 31B of the bracket 31; the upright 34 is fixed there by screwing. The base 37 extends substantially horizontally, towards the front, from a lower end of the upright 34. The base 37 of the pusher comprises a socket 36 and a beam 38 which horizontally connects the socket to a lower end of the upright 34 of the pusher 12.

[0021] The socket 36 of the pusher 12 comprises a cylindrical channel 41 around a substantially horizontal socket axis X41. The channel is open over its entire section through a front face of the socket. It is also open in an upper face of the socket, a slot connecting the channel with this upper face. The channel 41 has a diameter D41 substantially equal to the diameter D23 of the sphere 23, so that the sphere forms a linear-annular connection with the channel and can slide therein, along the socket axis X41. The slot 42 has a width L42 greater than the diameter D22B of the reduced section 22B of the rod 22 of the syringe 6, so that a clearance is provided on either side of the part 22B of the rod, so as to allow tilting of the rod around the socket axis X41.

[0022] Syringe 2 is removable, meaning that one syringe can be replaced by another. To install a syringe, the male fluid port 16 and the first female fluid port 46 should be aligned, the connector 23, here the sphere 23, should be inserted into the port 36 so that the X2 axis of the syringe is approximately vertical, and then the fluid ports 16 and 46 should be screwed together.

[0023] The pusher allows, by the action of the channel on the sphere, to push from the bottom upwards, and to pull from the top downwards, the piston 14. The freedom of movement of the sphere 23 in the channel 41 guarantees that the action of the pusher on the rod is directed along the axis X2 of the syringe.

[0024] The beam 38 comprises a substantially horizontal lower surface 38A. A strain gauge 44 is fixed to the lower face 38A. This gauge is intended to measure bending stresses around a horizontal axis transverse to the beam. The stresses thus measured are essentially dependent on the forces exerted by the syringe 2 on the pusher 12.

[0025] When the pusher 12 moves and moves with it the piston 14 of the syringe 2, forces are generated on the pusher. These forces come from the friction forces of the seal 21A of the piston and the pressure of the fluid in the chamber 19 of the syringe. The gauge 44 makes it possible in particular to evaluate the friction forces of the seal and the wear of the seal.

[0026] Weakening zones 39 are formed in the upper part of the beam 38. They make it possible to increase the sensitivity of the gauge 44. They are arranged so as to maintain sufficient stiffness in the beam 38 to guarantee satisfactory precision of the movement of the piston 14, and therefore of the dosage. In the example illustrated, the weakening zones consist of two half-cylinders 39, transverse to the beam, open upwards in an upper face of the beam. A current thickness of the beam, measured between the lower face and the bottom of the weakening zones 39, is noted E38. It is this thickness which determines the range of forces that the gauge 44 is capable of measuring.

[0027] There figure 6 illustrates a second embodiment for the pusher 12. It differs from the first embodiment, illustrated in figure 4, in that the section of the beam 38, transversely to the grip axis X41 is substantially constant and rectangular. In this configuration, if it allows uniform stresses to be had in the beam, for the same current thickness E8 of the beam, the bending displacement of the beam is greater than the same displacement, in the case of the first embodiment.

[0028] In this second embodiment, the gauge 44 can be fixed on an upper face 38B of the beam 38, instead of being arranged on the lower face 38A. Also, two gauges can be used, one on the lower face 38A, the other on the upper face 38B.

[0029] Measuring the seal friction forces in real time makes it possible to monitor the evolution of seal wear over time and helps prevent leaks and anticipate the replacement of the seal, or that of the syringe as a whole.

[0030] In the case where a system according to the invention is used to perform a dosage, as part of a diagnosis, the risks of errors are reduced, which is beneficial for the patient concerned.

[0031] Monitoring the seal wear is crucial as it helps prevent leaks and the resulting dosing errors. When the pump is a medication pump connected to an IV line, this reduces the risks to the patient receiving the infusion.

[0032] Measuring this wear also allows for planning syringe replacement and ensuring it is done at the right time—neither too early nor too late. Replacement is thus based on a physical measurement.

[0033] In addition, the pump 1 comprises control means for each of the motors

[0034] Any pressure variation generated in the chamber is transformed into force and is measured by the strain gauge.

[0035] With a single sensor, here gauge 44, we can measure both wear and pressure.

[0036] The motor 10 which actuates the pusher 12 and the motor 7 which actuates the valve 4 are stepper motors. The control means 8 comprise control means for the motors 7, 10 comprising, for each motor 7, 10, a current sensor. Each current sensor makes it possible to perform the following functions: Control of motor heating, which results from the current flowing in the motor; Control of motor torque, in particular of the syringe motor 10, since there is a link between current and torque; Prediction of motor wear, a link existing between the current consumed and the wear of the pump. Remote monitoring is advantageously implemented. An application comprising an algorithm, based on artificial intelligence, can advantageously be provided to assist with remote monitoring.

[0037] The pump also includes a sensor that allows monitoring its overall electrical consumption, which, in addition to controlling overall consumption, allows predicting an overall or remaining lifespan for the pump 1.

[0038] The pump may advantageously include other sensors, notably selected from an ambient air pressure sensor, an ambient temperature sensor, a vibration sensor, an infrared sensor, an ultrasonic sensor and / or a humidity sensor.

[0039] There is a link between air pressure and the pump's dosing function. Indeed, the dosing function is a relationship between the pressure variation generated by the piston movement and the atmospheric pressure present at the end of the hose (or sampling needle). Therefore, the ambient air pressure sensor, that is, the one in the location where the pump is located, allows the volume generated by the dosing function to be corrected.

[0040] There is also a link between volume and temperature. Thanks to the ambient temperature sensor, the dosing function is corrected or adjusted according to the ambient temperature. This temperature sensor also ensures that the product operates within the specified temperature range.

[0041] Pump 1 includes several mechanical movements that generate vibrations. The vibration sensor allows monitoring of vibration levels in order to predict and anticipate mechanical failures and malfunctions.

[0042] The ultrasonic sensor aims to measure sound generated by mechanical movements, also in order to predict and / or anticipate mechanical failures and malfunctions.

[0043] An infrared sensor is advantageously directed towards each of the motors 7, 10. It allows the actual temperature of the motor to be measured without contact. Since the pump 1 is generally installed in a confined environment, for example inside an analysis machine, precise control of the temperatures of the motors and of the heating in general is advantageous.

[0044] The humidity sensor measures the ambient humidity. It ensures that the pump is operating within a specified humidity range. In addition, if the pump leaks, the humidity level increases, and the humidity sensor can detect such a leak.

[0045] The control means 8 of the pump 1 advantageously comprise means of connection to a remote control device and / or for example to a “cloud”. These connection means may comprise a cellular, Bluetooth and / or Wi-Fi connection. These connection means make it possible to send data or measurements collected by the sensors to the remote control means, in real time or delayed.

[0046] The pump control means 8 are advantageously designed to receive incoming information. This incoming information may be specific configurations or a software update.

[0047] Sending sensor data to the cloud for analysis in real time or in delayed time allows us to provide the user with important services such as: a prediction of wear and anticipation of syringe replacement; a prediction of a need for maintenance; a prediction of failure; a prediction of end of life; and / or, a provision of alarms and information when the use of the product goes outside the specifications, for example outside a specific temperature or humidity range, in order to ensure that the dosage results are in line with a user's expectations.

[0048] A syringe pump according to the invention has the following characteristics: the linear movement of the piston 14 is achieved by a mechanical connection between a screw 28 and a nut 29 whereas the pumps of the prior art use a belt. The screw / nut connection provides the following improvements: mechanical simplicity which reduces the number of parts; reduction of total mechanical clearances, which improves the precision of the pump; space saving, due to a reduced number of parts; higher speeds and accelerations are possible; simplified manufacturing because it does not require adjustment of the tension of a belt; and, a longer service life than the service life of a belt. the linear movement of the piston 14 is further ensured by the linear guide 32 in order to withstand the forces; the pusher 12 has the function of pushing and pulling the piston 14 of the syringe 2 in order to perform the dosing function.

[0049] A single pump according to the invention may be designed to accept several syringe sizes, for example syringes capable of holding 100µl, 250µl, 500µl, 1000µl, 2.5ml, 5ml, 12.5µl, 25ml or 50ml. Such a pump may be designed to accurately dose volumes between approximately 0.1µl and 50ml.

[0050] Of course, the invention is not limited to the examples just described. On the contrary, the invention is defined by the claims which follow.

[0051] It will indeed appear to those skilled in the art that various modifications can be made to the embodiments described above, in light of the teaching which has just been disclosed to them.

[0052] In particular, the syringe axis may not be vertical. The pump may also include several syringes, driven by the same pusher or not.

[0053] Additionally, instead of being made of aluminum, the frame can also be made of a plastic material.

Claims

1. System (6) for actuating a piston (14) of a syringe (2) in a syringe pump (1), the piston being provided with a connector (23), comprising : - a motor (10); - transmission means (11); and - a pusher (12); the transmission means being designed to transmit an action of the motor to the pusher and the pusher being designed to move the piston in translation along a syringe axis (X2), said pusher comprising: - a socket (36) for said connector (23); - an attachment segment (34) designed to be attached to said transmission means; - a beam (38) that connects the socket (36) to the attachment segment, transversely to the syringe axis (X2); characterized in that it comprises - a sensor (44) for measuring a bending of said beam (44) about an axis perpendicular to the syringe axis (X2).

2. System according to claim 1, characterized in that the motor (10) is a rotary motor comprising a shaft forming a screw (28) and wherein the transmission means comprise a nut (29) screwed onto the screw (28) and a bracket (31) translationally connected with said nut, the attachment segment (34) of the pusher (12) being attached to said bracket (31).

3. System according to one of claims 1 and 2, characterized in that the motor (10) is a stepping motor.

4. System according to one of claims 1 to 3, characterized in that the sensor (44) is a strain gauge glued to a face (38A) of the beam (38).

5. System according to one of claims 1 to 4, characterized in that the socket (36) and the connector (23) form a linear-annular connection between them.

6. System according to claim 5, characterized in that the connector comprises a sphere (23) formed at one end of an axial rod (22B) of the piston (14) and in that the socket (36) comprises a cylindrical groove (41) and a slot (42), said groove (41) being designed to house said sphere therein, extending along an axis (X41) substantially perpendicular to the syringe axis (X2) and having a diameter (D41) substantially equal to a diameter (D23) of said sphere, and said slot (42) being provided for the passage with clearance of said rod (22B) when the sphere is in said groove.

7. System according to claim 6, characterized in that the groove comprises an axial opening for introducing the connector therein.

8. Precision pump (1), characterized in that it comprises a system according to one of claims 1 to 7.

9. Pump according to claim 8, characterized in that it comprises socket means (36, 46) for removably mounting a syringe therein.

10. Pump according to one of claims 8 and 9, characterized in that it further comprises at least one sensor from a current sensor for the motor (10), a sensor for the pressure of the ambient air, an ambient temperature sensor, a vibration sensor, an infrared sensor, an ultrasound sensor and a moisture sensor.

11. Pump according to one of claims 11 to 13, characterized in that it further comprises remote-control means and means for transmitting data read by the bending sensor (44) and, where applicable, one or more other sensors to said remote-control means.

12. Method for monitoring wear on a syringe in a pump according to one of claims 8 to 11, characterized in that the method uses data read by the bending sensor (44) and, where applicable, one or more other sensors.

13. Method according to claim 12, characterized in that it further comprises a prior learning step.