Active plunger

Abstract

Injection device (1) for injecting a medical fluid comprising: - A syringe (14) comprising a body (2) extending in a longitudinal direction (X) defining an inner space (15) and a plunger (3) configurated to separate said inner space (15) of said body (2) from an outer space (16) of said syringe (2), said plunger (3) configured for travelling back and forth within the inner space (15) along the longitudinal direction (X) comprising an evacuation path (10) and a first fixation mean (21), said evacuation path (10) comprises an internal chamber (45), said plunger (3) comprises a mobile selector (6) comprising at least a lower portion (11) and an upper portion (12), said lower portion (11) comprising a sealing surface (33), said mobile selector (6) configured to switch between a closed position in which said sealing surface (33) overlap said evacuation path (10) and an open position in which said mobile selector (6) liberate said evacuation path (10), - An injector (9) comprising a fluid detection system (8) and at least a motorized injector ram (4), said motorized injector ram (4) comprising a command stem (5), and a second fixation mean (22) configured to fix said first fixation mean (21), said fluid detection system (8) configured to trigger the command stem (5) when a fluid is detected, - A closing system (7) configured to allow said mobile selector (6) to switch from an open position to a closed position.

Description

[0001] Description

[0002] Title of the invention: Active plunger

[0003] Technical domain

[0004] [1] The present invention generally relates to an injection device for injecting a medical fluid, more particularly, to an injection device in the field of medical devices allowing the injection of liquids into the human body. More specifically, the invention relates to an injection device for injecting a medical liquid into a medical tubing from a medical liquid container.

[0005] Prior Art

[0006] [2] Injection devices are commonly used for injecting into a medical tubing a medical liquid from a medical liquid container. For example, the injection of medical liquid such as iodinated contrast agent is required in 70% of CT scan diagnosis cases. This injection, in about 70% of cases, is performed using an automated contrast agent injection device. Most often, such injection devices include a consumable, typically a syringe required to inject the contrast media to the patient thanks to an injector.

[0007] [3] An injector comprises at least a motorized injector ram and fixations means for contrast media containers. This injector can be manipulated thanks to a user interface from which instructions are given, such as pressure and flowrate...

[0008] [4] When the injection system is set up for injecting medical liquid into a patient, it is important to ensure that no gas is present in the tubing before injection. Injecting a gas such as air into a blood vessel of a patient may result in a gas embolism. Such occurrence may lead in the worst case to patient death, i.e. a blood vessel blockage caused by one or more bubbles of air or other gas in the circulatory system. When the consumable is put in place, the syringes and tubes are filled with air. It is therefore necessary to evacuate the gas present in the syringes and tubes before injection. Due to internal volume of syringes (typically between 100 and 200mL) and the length of the tubes, a large quantity of gas may necessitate to be evacuated from the injection system prior to injecting the patient.

[0009] [5] During injection, it may happen that gas is present in the injection device. For example, vaporization of the medical liquid may create gas. Also, some bubbles generated during the initial filling of the injection system may be blocked in the tubing or against the walls of the injection device and may not be evacuated during the initial purge. As a result, during injection, the injection device is positioned with the medical tubing interface downwards, so that any gas present in the injection device will be trapped in the injection device away from the medical tubing interface and will be the last to be injected into the common line.

[0010] [6] This approach suffers from several drawbacks. Firstly, the injection device must be moved alternatively between two opposite positions: with the medical tubing interface upwards (filling and purge) and downwards (injection). Secondly, this purge takes a significant time, and the presence of gas in the injection system must be monitored by an operator during the purge. The operator must also assess the quality of the purge and whether the purge is completed or not. As with every human interaction, reliance on an operator may lead to errors. Thirdly, the gas is pushed along the common line by medical liquid which also exits the injection system. This approach thereby involves wasting medical liquid and requires collecting the wasted medical liquid at the output of the injection system, with possible handling error.

[0011] [7] Injection devices are known from the prior art that include an automatic purge function relying on several pieces to function. Relying on so many pieces mathematically increase the risk that a piece is defective and thus that a malfunction occurs. In particular, a typical system that relies on a float that has a floating part and an obturating part.

[0012] [8] A float, by definition, must float to ensure its function relying on Archimede’s force. This requires a certain minimal float volume so that said obturating part reaches an evacuation path and closes it. However, the applicant found that this alternative is problematic for syringes of small diameter, such as those used in IRM operations. For example, given an internal diameter of around 20mm, it will be difficult to introduce this kind of float in such small diameter. For instance, in IRM operations, small diameter syringes can’t sustain such system. Indeed, such small syringes can’t sustain the minimal volume required to ensure the floating ability.

[0013] [9] Such device relies as well on the float without any insurance that a fluid has been detected, therefore, this type of injection device requires in any case a visual control from the user.

[0014]

[0010] Another issue is that such device relies on a strict respect of the verticality of the device so that obturating part of said float face correctly closes the evacuation path. Therefore, a user is very limited in the position of use of such device.

[0015]

[0011] It also has been determined that this type of injection device present several non-reusable parts. Therefore, said non-reusable parts generates costs and plastic waste. A calculation shows that if used at least 12 times a day during 250 days for 8 years, a total of at least 24000 non-reusable parts are thrown. 8 years correspond to the injector’s lifetime.

[0012] Finally, this type of injection device may need a permanent air mattress on top of the float to function correctly and prevent liquid to reach the air evacuation interface. However, the air as a gas has a compressible property, which is not the case with liquids, which may create an approximation on the volume to be injected. Such approximation may involve a failure in precision of fluid volume injected to the patient.

[0016]

[0013] Therefore, there is a need to reduce the disposable part to reduce costs and plastic waste for ecological reasons. There is also a need to provide a system with more precision usable in more complex situations and that may be used for all types of syringes whether bigger models such as for CT-scan operations or smaller models such as for IRM or Cath-lab operations.

[0017]

[0014] Therefore, there is a need to develop an injection device capable to solve aforementioned issues. In particular, an injection device is needed that may purge or evacuate the gas in various conditions. Other needs are that the injection device may be available in various sizes and that plastic waste is reduced.

[0018] Summary of the invention

[0019]

[0015] The invention makes it possible to resolve the problems mentioned above.

[0020]

[0016] In particular, the invention proposes a solution of an injection device, available in all sizes, capable to automatically purge air in various conditions and reduce drastically plastic waste.

[0021]

[0017] According to an embodiment, the invention is about injection device for injecting a medical fluid comprising:

[0022] A syringe comprising a body extending in a longitudinal direction X and a plunger, said body and said plunger defining an inner space, the syringe further comprising an evacuation path connected to the inner space and extending through the plunger, said evacuation path comprises an internal chamber, said plunger configured to travel back and forth within the body along the longitudinal direction X comprising a first fixation mean and a mobile selector, said mobile selector comprising at least a lower portion and an upper portion, said lower portion comprising a sealing surface, said mobile selector configured to switch between a closed position in which said sealing surface overlap said evacuation path and an open position in which said mobile selector liberates said evacuation path,

[0023] An injector comprising a fluid detection system and at least a motorized injector ram, said motorized injector ram comprising a command stem, and a second fixation mean configured to be fixed with said first fixation mean, said fluid detection system configured to detect a fluid in the internal chamber of said plunger and configured to trigger the command stem to push the mobile selector away when a fluid is detected, A closing system configured to allow said mobile selector to switch from said open position to said closed position.

[0024]

[0018] Thanks to these characteristics, in a closed position or in an initial position, the command stem is away from the mobile selector and the evacuation path remains closed by the surface sealing of the mobile selector which overlap said evacuation path. In this position, no fluid can go through said evacuation path. After initiating the injection device, when the fluid detection system detects air presence, said fluid detection system will transmit a triggering signal to the command stem, said command stem will push the mobile selector away from the evacuation path, therefore liberating said evacuation path and allowing the beginning of the purge. Indeed, thanks to an air density lower than liquid density, any air or gas that is trapped in the inner space will move upward and be first to be evacuated through the evacuation path.

[0019] Once the air or gas is evacuated through the purge, to avoid that said purge also evacuates the medical liquid, the fluid detection system can detect when a critical level is reached by a liquid at least in the internal chamber and to trigger the command stem to stop pushing on the mobile selector and to retrieve the initial position, in which the command stem is away from the mobile selector. This will enable the closing system to replace said mobile selector in the initial position.

[0025]

[0020] Thanks to these characteristics, the fluid detection system is comprised within the injector ram. Said motorized injector ram is not a disposable part and is always reused after each operation until the end of the injector’s lifetime. Therefore, having the fluid detection system located on the motorized injector ram enables the invention to also reuse said fluid detection system, hence reducing plastic waste. Indeed, thanks to these characteristics, the disposable parts are limited to the syringe, in particular, the body, the plunger, and the mobile selector.

[0026]

[0021] Thanks to these characteristics, providing an injection device with an automatic purge ability is useful in a multi-patient usage. Indeed, a user saves time by not purging manually each syringe, thereby optimizing the workflow, and increasing the “patient throughput”.

[0027]

[0022] Thanks to these characteristics, in a closed position, the mobile selector is in an upper position, while in an open position the mobile selector is in a lower position. Therefore, during the injection, the fluid within the syringe generates a pressure on the mobile selector. This enables to reinforce the tightness of said mobile selector in a closed position.

[0028]

[0023] According to an embodiment, the body comprises a lower end, said lower end comprising a medical tubing interface for connecting to a medical tubing through which the medical liquid can penetrate the inner space from the medical liquid container and can exit said inner space to be injected into the medical tubing.

[0029]

[0024] According to an embodiment, said closing system can be a hook configured to fix the command stem and is configured to grip said upper portion of the mobile selector, said hook configured to pull said upper portion when the command stem is triggered into a closed position.

[0030]

[0025] According to an embodiment, said mobile selector can be provided with a shoulder, said hook configured to grip said shoulder in a closed position and to liberate said shoulder in an open position.

[0031]

[0026] Thanks to these characteristics, a hook, is fixed to the upper portion of the mobile selector and limit the mobility of said mobile selector to a bi-directional movement. When the command stem is used to push away said mobile selector, the hook will generate a recall tension. Once triggered by the fluid detection system, the command stem will stop pushing the mobile selector and retract itself in an initial position. Afterward, said recall tension ensures that said mobile selector is replaced in a closed position.

[0032]

[0027] According to an embodiment, said closing system can be a spring fixed on said lower portion of the mobile selector.

[0033]

[0028] Thanks to these characteristics, a spring is fixed to the lower portion of the mobile selector and limits the mobility of said mobile selector to a bi-directional movement. This ensures that the mobile selector always face the evacuation path.

[0034]

[0029] According to an embodiment, said spring may be a compression spring configured to compress in an open position.

[0035]

[0030] Thanks to these characteristics, a compression spring will create a recall tension when the mobile selector is pushed away from the evacuation path as said mobile selector will contract said compression spring.

[0036]

[0031] According to an embodiment, said spring may be a tension spring configured to stretch in an open position.

[0037]

[0032] Thanks to these characteristics, a tension spring is fixed to the upper part of the mobile selector and will generate a recall tension if stretched.

[0038]

[0033] According to an embodiment, said spring can be made in polyoxymethylene.

[0039]

[0034] Thanks to these characteristics, the polyoxymethylene (POM) is biocompatible in comparison to a metallic spring and therefore well suited to be used for a spring for medical use.

[0040]

[0035] According to an embodiment, said first fixation mean is a groove comprising a first radial groove surface and a second radial groove surface, said second fixation mean is a rib, said second fixation mean comprise a first radial groove surface configured to bear on said first radial rib surface when the motorized injector ram push on the plunger, and a second radial rib surface configured to bear on said second radial groove surface when the injector ram pulls the plunger.

[0041]

[0036] Thanks to these characteristics, said fixations mean enables that the plunger travel upwards or downwards by pushing or pulling said plunger longitudinally within the body of the syringe.

[0042]

[0037] According to an embodiment, said command stem can comprises a free terminal portion comprising a first bearing surface and said upper portion of said mobile selector comprises a second bearing surface, said first bearing surface configured to bear on said second bearing surface when the command stem is triggered into an open position.

[0038] According to an embodiment, said mobile selector can present a radial diameter strictly inferior to 10 mm.

[0043]

[0039] Thanks to these characteristics, a mobile selector presenting a radial diameter strictly inferior to 10 mm can be inserted in all types of syringes whether for Cath-Lab, MRI, or CT-scan operations.

[0044]

[0040] According to an embodiment, said mobile selector may present a radial diameter comprised between 1 and 9 mm.

[0045]

[0041] According to an embodiment, said motorized injector ram may comprise at least a distal end, said distal end configured to face the plunger and comprises said fluid detection system.

[0046]

[0042] According to an embodiment, said injector may comprise a processor configured to convert a detection signal to an activating signal triggering the motorized injector ram.

[0047]

[0043] According to an embodiment, said fluid detection system may detect a fluid in the internal chamber of said plunger.

[0048]

[0044] According to an embodiment, said fluid detection system may be a liquid and / or an air detection system.

[0049]

[0045] According to an embodiment, said fluid detection system may be selected between a light beam detector, a sound beam detector, a strain gauge, or an energy consumption detector.

[0050]

[0046] Thanks to these characteristics, a light beam detector can detect a variation of the environment whether it’s air or liquid. Specifically, a light beam detector can detect a diffraction of the light. A diffraction of the light will be triggered when there is a switch from air to liquid. Therefore, once a diffraction is detected said light beam detector will trigger a signal emission toward the command stem so it will stop said command stem from pushing. Once the command stem is stopped from pushing, this will allow the closing system to replace the mobile selector to a closed position.

[0051]

[0047] Thanks to these characteristics, a sound beam detector can detect a variation of the environment whether it’s air or liquid. Specifically, a sound beam detector can detect a diffraction of the sound. Once a diffraction is detected said sound beam detector will trigger a signal emission first toward the command stem so it will stop it from pushing, allowing the closing system to replace the mobile selector to a closed position.

[0052]

[0048] Thanks to these characteristics, a strain gauge can detect the newton force applied by the command stem. As soon as the plunger will contact a liquid, it will necessitate more strength to push the command stem on the mobile selector. This differential of force can be detected by the strain gauge. As soon as said differential of force is detected, said strain gauge will trigger a signal emission toward the command stem to stop said command stem from pushing.

[0053]

[0049] Thanks to these characteristics, the energy consumption detector measures the consumption of energy required to push with the command stem. Once a differential of consumption is detected, for instance when there is a change of nature of fluid from air to liquid, a signal is emitted to stop the command stem from pushing the mobile selector, allowing the closing system to reposition the mobile selector in a closed position.

[0054]

[0050] According to an embodiment, said fluid detection system may comprise a light beam transmitter and a light beam receiver, said light beam receiver configured to transmit a triggering signal to the command stem into a closed position when a liquid is detected or in an open position when air is detected.

[0055]

[0051] According to an embodiment, said fluid detection system may comprise a sound beam transmitter and a sound beam receiver, said sound beam receiver configured to transmit a triggering signal to the command stem into a closed position when a liquid is detected or in an open position when air is detected.

[0056]

[0052] Thanks to these characteristics, having a light and / or sound beam emitter and receiver enables to have a direct detection mode. This means that the system can “see” the liquid or the air and make a differentiation. These kinds of systems are more accurate because they rely on less variability, therefore they are much reliable and easier to be piloted.

[0057]

[0053] According to an embodiment, said plunger may comprise at least a sealing joint configured to lean on the body and configured for travelling back and forth within the inner space along the longitudinal direction (X).

[0058]

[0054] Thanks to these characteristics, the sealing joint enables that the plunger ensures that no fluid can go from the inner space to the outer space and reciprocally. The plunger remains movable with said sealing joint. Indeed, the sealing joint will also travel in a bi-directional way when the injector ram push or pulls the plunger without compromising the seal.

[0059]

[0055] According to an embodiment, the injection device wherein said sealing surface may be selected between a conical surface, frustoconical surface, toroidal surface, or a cylindrical surface. Summary of the figures:

[0060]

[0056] The invention will be better understood, and other aims, details, characteristics, and advantages of the invention will appear more clearly during the following description of several embodiments of the invention, given solely for illustrative and non-limiting purposes, with reference to the attached drawings.

[0061] Figure 1 is a longitudinal sectional view of an injection device according to a first embodiment of the invention in a closed position.

[0062] Figure 2 is a view similar to that of Figure 1, with the injection device in an open position.

[0063] Figure 3 is a longitudinal sectional view of an injection device according to a second embodiment of the invention.

[0064] Definition(s):

[0065]

[0057] Purge refers to the removal of trapped air from the syringe prior to injection. In the present invention, opening the evacuation path allows the air to escape. However, it is by pushing on the plunger that the air is forced out at least until said plunger comes into contact with an injection liquid. Once the liquid is reached and detected, the purge is considered complete, and the evacuation path is closed thanks to the replacement of the mobile selector to a closed position. The liquid can then be safely injected into the patient.

[0066]

[0058] Aspiration refers to the action of filling the syringe, this step is normally conducted before the purge.

[0067]

[0059] Injection refers to the action of injecting a medical liquid into a patient. Therefore, in a cycling view, there is first an aspiration, then a purge and finally an injection. Choice remains to the user to repeat said cycle.

[0068]

[0060] Body refers to the body or the barrel of a syringe. Said barrel is a hollow cylinder-shaped component.

[0069]

[0061] Inner space refers to the inner space of the body, thus, the inner space of a syringe. Said inner space can contain fluids such as medical liquid and / or air. The inner space is delimited by the body and the plunger. The inner space has a variable volume depending on the distance travelled by the plunger within said body.

[0070]

[0062] Outer space, in contradiction to the inner space, refers to all the space outside the syringe, such as the room’s space and doesn’t belong to the invention.

[0071]

[0063] A plunger according to our invention, refers to a cylindrical structure separating an inner space of the syringe from the outer space.

[0072]

[0064] By a hook we intend a mechanism fixed on a command stem, most likely (but not necessarily) on the lower part of said command stem, equipped with arms designed to engage with an upper portion of a mobile selector. Specifically, this mobile selector includes a shoulder or any portion that is accessible to the hook and that can be used as a gripping point. The arms of said hook are configured to grip this shoulder or portion. Conversely, if the hook is retractable, the arms may also be configured to release the shoulder or the portion to ease the insertion of said portion or shoulder, allowing for selective engagement and disengagement with the mobile selector.

[0073]

[0065] Command stem refers to a longitudinal tool able to bear and push on a bearing surface of the mobile selector to push it away. In an initial position, the command stem is away from the mobile selector, meaning there are no contact between the command stem and the mobile selector. Once triggered, said command stem can push on the mobile selector until given another order or signal to stop said pushing and retract itself to said initial position.

[0074]

[0066] Motorized injector ram refers to a precision mechanism designed for controlled drug delivery via injection. It operates autonomously and remotely ensuring accurate dosing. The injector may incorporate components such as a Maxon motor DCX12S, which provides power within a compact 12 mm diameter. It may also use state-of-the-art electronics and connectivity such as NFC, Bluetooth, and OLED screen for monitoring the injection process.

[0075]

[0067] Open position is defined as the state in which the evacuation path is free and unobstructed. In this position, the mobile selector does not block the evacuation path, allowing for unrestricted passage and purge initiation.

[0076]

[0068] Closed position is defined as the state in which the evacuation path is blocked by the mobile selector. In this position, the mobile selector has a sealing surface that obstructs or overlaps the evacuation path, preventing any flow through it. At the same time, in a closed position, the command stem is away from the mobile selector meaning that there are no contact between them.

[0077]

[0069] The alternative between a closed position and open position is relevant specifically to the purge.

[0078]

[0070] By axial surface we mean a surface which extends axially along a longitudinal axis X. The surface which extends axially may admit local discontinuities, said discontinuities being able to take the form of a bump or a hollow.

[0079]

[0071] By radial surface we mean a surface which extends radially from a longitudinal axis X. The surface which extends axially may admit local discontinuities, said discontinuities being able to take the form of a bump or a hollow.

[0080]

[0072] In the description and claims, the terms ‘exterior’ and ‘interior’ and the orientations ‘axial’ and ‘radial’ can be used to designate, according to the definitions given in the description, elements of the device. The longitudinal axis X determines the ‘axial’ orientation. The ‘radial’ orientation is directed orthogonally to the longitudinal axis X. The ‘circumferential’ orientation is directed orthogonally to the rotation axis X and orthogonal to the radial direction, that is, orthoradially. The terms ‘outer’ / ‘inner’, ‘exterior’ / ‘external’ or ‘interior’ / ‘internal’ can be used to define the orientation or relative position of a component with respect to another, in reference to the longitudinal axis X. Description of the embodiments and figures:

[0081]

[0073] Figure 1 shows an injection device 1 for injecting a medical fluid according to the invention. Said injection device 1 comprises a syringe 14, an injector 9 and a closing system 7.

[0082]

[0074] Said syringe 14 comprises a body 2 extending in a longitudinal direction X defining an inner space 15 and a plunger 3 configurated to separate said inner space 15 of said body 2 from an outer space 16 of said syringe 2. Said plunger 3 is configured for travelling back and forth within the inner space 15 along the longitudinal direction (X). The syringe 14 (including all its components) is a disposable part, meaning a user must throw it after each use. The body 2 present a cylindrical form and can contain liquids such as contrast agent medias.

[0083]

[0075] The plunger 3 also present a cylindrical form to fit within said body 2. The invention may admit other forms for the body 2 and the plunger 3. The plunger 3 remains movable upward or downward inside the body 2 while ensuring the separation between the inner space 15 and the outer space 16. Said plunger 3 comprises two sealing joints 40 to enhance the sealing, but one sealing joint 40 can be enough to insure a better sealing function. The plunger comprises an evacuation path 10 that enables a passage through said plunger 3, that can connect or disconnect the inner space from the outer space 16. Therefore, said sealing joint 40 makes sure that the only passage between the inner 15 and outer space 16 is through the evacuation path 10.

[0084]

[0076] The plunger 3 comprises an evacuation path 10. Said evacuation path comprises an internal chamber 45.

[0085]

[0077] The plunger 3 comprises a mobile selector 6. The mobile selector 6 comprises a lower portion 11 and an upper portion 12. Said lower potion 11 present a conical shape and comprise a sealing surface 33. Said sealing surface 33 is a frustoconical surface. Said mobile selector 6 is configured to switch between a closed position (Figure 1) in which said sealing surface 33 overlaps said evacuation path 10 and an open position (Figure 2) in which said mobile selector 3 liberates said evacuation path 10.

[0086]

[0078] Other types of surfaces for the sealing surface 33 are also admitted by the invention, such as conical surface, toroidal surface, or a cylindrical surface. Another variant of the invention admits that the sealing surface 33 comprise an elastomeric joint configured to close the evacuation path 10 in a closed position.

[0087]

[0079] The lower portion 11 and upper portion 12 are connected by a longitudinal shaft 42. However, the invention admits other variants in which there is no longitudinal shaft 42, and in which said portions 11, 12 are in one piece. Other variants admit that said portions 11, 12 and the longitudinal shaft 42 are in one single piece of same material.

[0088]

[0080] The injector 9 comprises a command stem 5 and a motorized injector ram 4. The injector 9 may also comprise an interface user (not shown) to control the flowrate or other parameters as such.

[0089]

[0081] The motorized injector ram 4 extends longitudinally along an axis X and comprises a distal end 48. Said distal end comprises a fluid detection system 8. Said fluid detection system is configured to detect a fluid in the internal chamber 45. The motorized injector ram 4 comprise a second fixation mean 22. Said second fixation mean 22 is a rib that comprises a first radial rib surface 23 and a second radial rib surface 24.

[0090]

[0082] Said motorized injector ram 4 hosts internally said command stem 5 which extends longitudinally. Said command stem 5 comprises a free terminal portion 30 and a first bearing surface 31. The upper portion 12 of said mobile selector 6 comprise a second bearing surface 32 facing said first bearing surface 31. Said first bearing surface 31 is configured to bear on said second bearing surface 32 when the command stem is activated. The first bearing surface 31 is configured to release said second bearing surface 32 when the command stem 5 is signaled by the fluid detection system 8 to stop from pushing and retracting to an initial position.

[0091]

[0083] The plunger 3 comprise a first fixation mean 21 in a mushroom shape that surrounds said longitudinal shaft 42 of the mobile selector 6. Said first fixation mean 21 is a groove that comprises a first radial groove surface 25 and a second groove surface 26.

[0092]

[0084] Said first radial rib surface 23 configured to bear on said first radial groove surface 25 when the motorized injector ram 4 push longitudinally on the plunger 3. Said second radial rib surface 24 configured to bear on said second radial groove surface 26 when the injector ram 4 pulls longitudinally the plunger 3.

[0093]

[0085] This mushroom shape fixation mean 21 is used to link the plunger 3 to the motorized injector ram 4, in particular, for aspiration purposes.

[0086] Thanks to these characteristics, said fixation means 21, 22 enable the motorized injector ram 4 to remain always fixed to the plunger 3. Indeed, said motorized injector ram 4 is blocked longitudinally because the rib of the first fixation mean 21 of the plunger 3 is trapped longitudinally inside said motorized injector ram’s groove.

[0094]

[0087] In figure 1, a gap remains between the second radial rib surface 24 and the second radial groove surface 26. This gap facilitates the installation of the syringe 14 into the injector 9. It is not required for the purge activity.

[0095]

[0088] The plunger 3 comprises a recess 49. Said recess 49 is configured to accommodate said distal end 48. As the fluid detection system 8 is in the extremity of said distal end 48, this enables to bring in this case the liquid detection system as close as possible to the internal chamber 45 and to detect in this area any fluid and specifically any liquid reach.

[0096]

[0089] In figure 1, said mobile selector present a radial diameter comprised between 1 and 9 mm and more specifically substantially equal to 5 mm.

[0097]

[0090] In an initial position, or closed position, the command stem 5 is not in contact with the upper portion 12 of the mobile selector 6. The command stem 5 is rather retracted within the motorized injector ram 4.

[0098]

[0091] Said fluid detection system 8 may be a liquid and / or an air detection system. Indeed, as soon as the fluid detection system 8 detects air, the purge is activated. An activated purge means that the command stem 5 starts pushing on the mobile selector 6 and liberate the evacuation path.

[0099]

[0092] If no air is detected or if liquid is detected the system either remains closed or is configured to replace the whole injection device 1 in a closed position. Indeed, the injection device 1 comprises a closing system 7 configured to allow said mobile selector 6 to switch from an open position to a closed position, said fluid detection system 8 configured to trigger the command stem 5 when a liquid is detected. By trigger, we intend that said fluid detection system 8 is configured to signal and stop command stem 5 from pushing and signal to retrieve said command stem 5 initial position.

[0100]

[0093] Said plunger 3 comprise an internal chamber 45 that connect the evacuation path 10 and the inner space 15. Said internal chamber 45 comprises an internal radial surface 46 facing the bottom of the lower portion 11. Specifically, said closing system 7 is a spring 19. A first extremity of said spring 19 rests on said internal radial surface 46 of the plunger 3. Therefore, said spring 19 may use said internal radial surface 46 as a support. The other opposed extremity of said spring 19 rests against the bottom of the lower portion 11. Other variation of the invention admits that the spring 19 is solidly fixed rather than resting on radial surface 46 and against the bottom of the lower portion 11.

[0101]

[0094] The invention admits a variation in which the spring 19 is rests upwardly against the bottom of the longitudinal shaft 42, therefore, said longitudinal shaft being much longer.

[0102]

[0095] Another variation consists in having the spring 19 resting on the bottom of a longitudinal shaft 42 through an intermediate support portion.

[0103]

[0096] The spring 19 fixed to the lower portion of the mobile selector enables to limit the mobility of said mobile selector to a bi-directional movement. This ensures that the mobile selector always face the evacuation path.

[0104]

[0097] Said spring in fig. 1 is a compression spring, in a closed position, said compression spring is in its initial position uncompressed. Indeed, a compression spring will create a recall tension when the mobile selector is pushed away (such as in fig. 2) from the evacuation path as said mobile selector will contract said compression spring.

[0105]

[0098] The invention admits another variation in which the spring is a tension spring configured to stretch in an open position. A tension spring is fixed to the upper part of the mobile selector and will generate a recall tension if stretched.

[0106]

[0099] The invention admits other variants in which said spring 19 rests against different kind of support and in which there is no internal chamber. In this case the fluid detection system 8 may be configured to detect a critical level in the inner space 15.

[0107]

[0100] Said spring 19 is made in polyoxymethylene (POM). Indeed, the polyoxymethylene (POM) is biocompatible in comparison to a metallic spring and therefore well suited to be used for a spring for medical use.

[0108]

[0101] In figure 1, the fluid detection system 8 is a light beam detector. Said light beam detector comprise a light beam transmitter 35 and a light beam receiver 36. said light beam receiver 36 is configured to transmit an activating signal to the closing system 7 when a liquid blocks the emission from said light beam transmitter 35.

[0109]

[0102] A light beam detector can detect a variation of the environment whether it’s air or liquid. Specifically, a light beam detector can detect a diffraction of the light. A diffraction of the light will be triggered when there is a switch from air to liquid. Therefore, once a diffraction is detected said light beam detector will trigger a signal emission toward the command stem so it will stop said command stem from pushing. Once the command stem is stopped from pushing, this will allow the closing system to replace the mobile selector to a closed position.

[0110]

[0103] Other variants of the fluid detection system are also admitted by the invention.

[0111]

[0104] A first variant consists of having a sound beam detector instead of a light beam detector. Said sound beam detector comprise a sound beam transmitter and a sound beam receiver, said sound beam receiver configured to transmit an activating signal to the closing system when a liquid deflects or diffract the emission from said sound beam transmitter.

[0112]

[0105] Thanks to these characteristics, said sound beam detector can detect a variation of the environment whether it’s air or liquid. Specifically, a sound beam detector can detect a diffraction of the sound. Once a diffraction is detected said sound beam detector will trigger a signal emission first toward the command stem so it will stop it from pushing, allowing the closing system to replace the mobile selector to a closed position.

[0113]

[0106] A second variant consist of having a strain gauge instead of the light beam detector. Said stain gauge can detect the newton force applied by the command stem. As soon as the plunger will contact a liquid, it will necessitate more strength to push the command stem on the mobile selector. This differential of force can be detected by the strain gauge. As soon as said differential of force is detected, said strain gauge will trigger a signal emission toward the command stem to stop said command stem from pushing.

[0114]

[0107] A third variant consist of having an energy consumption detector. The energy consumption detector differs from a strain gauge in that it is the consumption of energy required to push with the command stem that is measured. Once a differential of consumption is detected, for instance when there is a change of nature of fluid from air to liquid, a signal is emitted to stop the command stem from pushing the mobile selector, leaving the closing system reposition the mobile selector in a closed position.

[0115]

[0108] Fig. 2 illustrates the injection device 1 same as in fig 1 but in an open position. Therefore fig. 2 differs from fig. 1 in that the injection device 1 is in an open position and as follows:

[0116]

[0109] The mobile selector 6 is away from the evacuation path 10. More specifically, said mobile selector 6 is longitudinally away from said evacuation path 10. Indeed, the command stem 5 through its free terminal portion 30 and the first bearing surface 31 bears on the second bearing surface 32 of the upper portion 12 of said mobile selector 6.

[0117]

[0110] In this configuration the spring 19 is compressed thanks to the action of the command stem 5. Only when liquid is detected than the fluid detection system 8 will trigger the command stem to stop the pushing action and in a second time the retractation of said command stem 5. Automatically the compressed spring will retrieve its initial position by releasing the compression tension, therefore bringing the mobile selector into a closed position.

[0118]

[0111] Fig. 3 shows an alternative of an injection device. Therefore fig. 3 differs from fig. 1 in that the closing system 7 of said the injection device 1 comprises a hook 18 instead of a spring 19.

[0119]

[0112] The hook 18 is fixed to the command stem 5. Therefore, the command stem 5 moves, upwardly or downwardly, in synchronicity with the hook, in the same direction and for the same distance. Said hook 18 grips the upper portion 12 of the mobile selector 6. To this end, said hook 18 comprises arms that can grip said upper portion 12. Said upper portion 12 is inserted and hosted in said groove shape arms. Thanks to that gripping, said hook 18 can pull said upper portion 12 when the command stem 5 is triggered.

[0120]

[0113] Therefore, when the fluid detection system 8 detects presence of air, said command stem 5 start pushing on the upper portion 12 of the mobile selector 6 thanks to the first bearing surface 31 that bears on the second bearing surface 32.

[0121]

[0114] Once a liquid is detected by the fluid detection system 8, the command stem 5 is triggered into a closed position, meaning that the command stem will retract itself upwardly. However, as the hook is attached to the upper portion 12 of the mobile selector 6, the hook will inevitably pull said mobile selector 6 replacing the sealing surface 33 in a closed position and blocking therefore the evacuation path 10.

[0122]

[0115] Additional sealing joints are added to enhance the sealing ability of the sealing surface 33 but are not mandatory. Indeed, the invention admits a variant in which there are no additional sealing joints.

[0123]

[0116] The invention admits a variant in which said hook 18 is retractable and can selectively grip the upper portion 12 of the mobile selector 6. Therefore, the arms can also release the upper portion 12 or ease the insertion of said portion 12, allowing for selective engagement and disengagement with the mobile selector 6.

Claims

Claims1. Injection device (1) for injecting a medical fluid comprising:A syringe (14) comprising a body (2) extending in a longitudinal direction (X) and a plunger (3), said body (2) and said plunger (3) defining an inner space (15), the syringe (14) further comprising an evacuation path (10) connected to the inner space (15) and extending through the plunger (3), said evacuation path (10) comprises an internal chamber (45), said plunger (3) configured to travel back and forth within the body (2) along the longitudinal direction (X) comprising a first fixation mean (21) and a mobile selector (6), said mobile selector (6) comprising at least a lower portion (11) and an upper portion (12), said lower portion (11) comprising a sealing surface (33), said mobile selector (6) configured to switch between a closed position in which said sealing surface (33) overlap said evacuation path (10) and an open position in which said mobile selector (6) liberates said evacuation path (10),An injector (9) comprising a fluid detection system (8) and at least a motorized injector ram (4), said motorized injector ram (4) comprising a command stem (5), and a second fixation mean (22) configured to be fixed with said first fixation mean (21), said fluid detection system (8) configured to detect a fluid in the internal chamber (45) of said plunger (3) and configured to trigger the command stem (5) to push the mobile selector (6) away when a fluid is detected, A closing system (7) configured to allow said mobile selector (6) to switch from said open position to said closed position.

2. Injection device (1) according to claim 1, wherein said closing system (7) is a hook(18) configured to fix the command stem (5) and is configured to grip said upper portion (12) of the mobile selector (6), said hook (18) configured to pull said upper portion (12) when the command stem is triggered into a closed position.

3. Injection device (1) according to claim 1, wherein said closing system (7) is a spring(19) fixed on said lower portion (11) of the mobile selector (6).

4. Injection device (1) according to claim 3, wherein said spring (19) is a compression spring configured to compress in an open position.

5. Injection device (1) according to any of claims 3 or 4, wherein said spring (19) is made in polyoxymethylene.

6. Injection device (1) according to any of preceding claims, wherein said first fixation mean (21) is a groove comprising a first radial groove surface (25) and a second radial groove surface (26), said second fixation mean (22) is a rib, said second fixation mean (22) comprise a first radial groove surface (23) configured to bear on said first radial rib surface (25) when the motorized injector ram (4) push on the plunger (3), and a second radial rib surface (24) configured to bear on said second radial groove surface (26) when the injector ram pulls the plunger (3).

7. Injection device (1) according to any of preceding claims, wherein said command stem (5) comprises a free terminal portion comprising (30) a first bearing surface (31) and said upper portion (12) of said mobile selector (6) comprises a second bearing surface (32), said first bearing surface (31) configured to bear on said second bearing surface (32) when the command stem (5) is triggered.

8. Injection device (1) according to any of preceding claims, wherein said mobile selector (6) present a radial diameter strictly inferior to 10 mm.

9. Injection device (1) according to claim 8, wherein said mobile selector (6) present a radial diameter comprised between 1 and 9 mm.

10. Injection device (1) according to any of preceding claims, wherein said motorized injector ram (4) comprises at least a distal end (48), said distal end (48) configured to face the plunger (3) and comprises said fluid detection system (8).

11. Injection device (1) according to any of preceding claims, wherein said fluid detection system (8) is a liquid and / or an air detection system.

12. Injection device (1) according to any of preceding claims, wherein said fluid detection system (8) is selected between a light beam detector, a sound beam detector, a strain gauge, a force sensor, or an energy consumption detector.

13. Injection device (1) according to claim 12, wherein said fluid detection system (8) comprises a light beam transmitter (35) and a light beam receiver (36), said light beam receiver (36) configured to transmit a triggering signal to the command stem (5) into a closed position when a liquid is detected or in an open position when air is detected.

14. Injection device (1) according to any of preceding claims, wherein said plunger (3) comprises at least a sealing joint (40) configured to lean on the body (2) and configured for travelling back and forth within the inner space (15) along the longitudinal direction (X).

15. Injection device (1) according to any of preceding claims, wherein said sealing surface (33) is selected between a conical surface, frustoconical surface, toroidal surface, or a cylindrical surface.

Images