Medical infusion equipment with gas exhaust

Abstract

The injection device (1) for injecting a medicinal liquid includes a piston (6) disposed within an interior space (4) that defines an upper space (4b) and a lower space (4a), an exhaust path that traverses the piston (6) from the lower space (4a) to the upper space (4b) of the interior space, a selector (24) between a lower portion (17a) and an intermediate portion (17b) of the exhaust path that is configured to selectively allow gas to pass and prevent the medicinal liquid from passing through selectors (24, 50, 60), and a purge valve (22) between the intermediate portion (17b) of the exhaust path and an upper portion (17c) of the exhaust path that is configured to move between a passing configuration requiring excess pressure in the intermediate portion (17b) created by the piston (6) moving toward the lower end of the body (2) and a blocking configuration.

Description

[Technical field]

[0001] FIELD OF THEINVENTION The present invention relates generally to the injection of medical fluids, and more particularly to an injection device for injecting medical fluids from a medical fluid container into medical tubing. [Background technology]

[0002] Injection devices are commonly used to inject medical fluids from a medical fluid container into medical tubing. For example, the injection of medical fluids, such as iodine contrast media, is required in 70% of CT scan diagnostic cases. This injection is performed using an automatic contrast injector in approximately 70% of cases. Injection tubing is required to connect the automatic injector to the patient.

[0003] US Patent Application Publication No. 2012 / 0209111 discloses a bagged syringe for a fluid delivery system, including a cylindrical body, a cap and bag assembly, a plunger element disposed within the cylindrical body, and a mounting assembly for securing the cap and bag assembly to the cylindrical body. The cylindrical body has a distal end and a proximal end and defines a throughbore. The cap and bag assembly is adapted to connect to the distal end of the cylindrical body and includes a cap body and a bag. The cap body defines an internal cavity and a distal discharge conduit and is adapted to engage the distal end of the cylindrical body. A disk-shaped bag is disposed within the internal cavity and typically includes a central membrane portion. The plunger element is disposed within the throughbore of the cylindrical body and is vented to allow evacuation of a space within the cylindrical body between the cap and bag assembly and the plunger element.

[0004] US 2006 / 0249541 discloses a fluid dispensing device including a bottle for receiving a fluid, a discharge tube, and a pressurizing device connected between the bottle and the discharge tube for pressurizing the fluid and for forcing the fluid to flow through the discharge tube without gravity. The pressurizing device includes a container connected between the bottle and the discharge tube, a piston slidably received in the container, and a moving device for moving the piston in a reciprocating motion within the container. For example, a motor is connected to the piston by means of a crank for moving the piston in a reciprocating motion within the container.

[0005] U.S. Patent Application Publication No. 2005 / 0215850 discloses a syringe pump including a syringe including a plunger sliding within a body having an ejection port, a drive mechanism coupled to the syringe, the drive mechanism including a cylinder within which a piston mounted on a shaft slides, and a biasing device operative to apply a biasing force to the piston to drive it distally within the cylinder, and a safety stop that initially prevents the biasing device from moving the piston, the safety stop being removable to allow the biasing device to move the piston.

[0006] FIG. 1 shows an example of an infusion system 100 for injecting a medical fluid from a medical fluid container 104 into a common line 102. Those skilled in the art will recognize that the medical fluid container 104 can be any type of container specifically adapted to contain a medical fluid, such as, but not limited to, a vial, a bottle, a plastic container, and any type of container manufactured for containing a medical fluid. The infusion system includes a first connector 106 configured to be connected to the medical fluid container 104, an injector 108 to which an infusion device 110 with a medical tubing interface 112 is attached, a medical fluid supply line 114 configured to connect the first connector 106 to the medical tubing interface 112 to supply the medical fluid to the infusion device 110, and a common line 102 configured to be connected to the medical tubing interface 112 and the patient line 116 to inject the medical fluid into the patient line 116. More precisely, a first tubing valve 130 connects the liquid supply line 114 to the common line 102 and only allows passage to the common line 102 under vacuum pressure. The common line 102 includes a second tube valve 140 downstream of the first tube valve 130 to allow passage only towards the patient line 102. The infusion device 110 typically includes a body defining an interior space and a piston actuated by a plunger rod and configured to move within the interior space to pump fluid into or pump fluid out of the interior space.

[0007] In the illustrated example, two different types of medicinal fluids are to be injected into the patient, and as a result the injection system is configured to be connected to two medicinal fluid containers 104 using two different first connectors 106 and two different medicinal fluid supply lines 114. However, the injection system may also be configured to inject only one medicinal fluid. Since bi-injection simply involves repeating the features described, for the sake of brevity, the following description is made with reference to a configuration in which only one medicinal fluid is injected. Herein, "bi-injection" is understood to mean two-injections.

[0008] For economic and environmental reasons (less plastic use), multi-patient practices are steadily gaining market share. In the so-called multi-patient practice, the tubing for the injection system comprises two very different parts: a day set 120 and a patient set 122. The patient set 122 is changed for each patient. The patient set 122 is typically used to limit the risk of cross-contamination between successive patients, thus protecting the day set. Once installed and prepared, the day set 120 remains connected to the power injector for several patient cases, as long as the same medical fluid is injected. If the medical fluid to be injected needs to be changed, the day set 120 is changed. This day set 120 includes a medical fluid supply line 114 connected to the medical fluid container 104 and the common line 102. The patient set 122 includes a patient line 116, to which the medical fluid is supplied by the common line 102, connected to a catheter or needle for injecting the medical fluid into the patient.

[0009] When the injection system 100 is set to inject a medical solution into a patient, it is important to ensure that there is no gas in the tubing prior to injection. Injection of a gas, such as air, into the patient's blood vessels can result in gas embolism, i.e., a vascular blockage caused by one or more bubbles of air or other gas in the circulatory system. When the day set 120 or patient set 116 is in place, the tubing fills with air. Therefore, it is necessary to evacuate any gas present in the tubing prior to injection. Due to the length of the tubing, a large amount of gas will be evacuated from the injection system 100.

[0010] To purge the injection system 100 of any gas present before injection, the injection device 110 draws or pulls in the medical fluid from the medical fluid container 104, thereby filling the medical fluid supply line 114. The injection device 110 is now filled with a mixture of medical fluid and gas. The injection device 110 is then positioned with the medical tube interface 112 up so that the gas is collected at said medical tube interface 112. It should be noted that filling the injection device 110 creates turbulence in the medical fluid, which creates microbubbles in the medical fluid. Due to the high viscosity of the medical fluid (especially for contrast media), it may take several minutes for the microbubbles to reach the medical tube interface 112. Therefore, it is customary to wait at least 2 or 3 minutes with the medical tube interface 112 up. Then, by actuating the piston, the gas is evacuated from the injection device 110 through the still-up medical tube interface 112 into the common line 102. A chemical solution is then injected into the common line 102 to push the gas out of the common line 102, thereby purging the gas from the injection system 100.

[0011] During injection, gas may be present in the infusion set 110. For example, gas may be generated by vaporization of the medical fluid. Also, some gas bubbles generated during the initial filling of the infusion system 100 may be trapped in the tubing or on the walls of the infusion set 110 and may not be evacuated during the initial purge. As a result, during injection, the infusion set 110 is positioned with the medical tubing interface 112 facing down, so that gas present in the infusion set 100 is trapped within the infusion set 100 away from the medical tubing interface 112 and is not injected into the common line 102.

[0012] This approach has several drawbacks. First, the infusion device 110 must be moved between two opposing positions with the medical tube interface 112 either up or down. This requires that the injector 108 be rotatable. Second, this purging takes a significant amount of time, and the infusion system 100 must be monitored by an operator during the purging. The operator must also evaluate the quality of the purge and whether it is complete. As with any human interaction, dependency on the operator can lead to errors. Third, the gas is pushed along the common line 102 by the medical fluid also exiting the infusion system. This means that this approach involves waste of medical fluid, which must be collected at the outlet of the infusion system 100, which can lead to mishandling.

[0013] Also, even if gas is trapped in the injector 110, the gas still present in the injector 110 after purging may alter the operation of the injector. The dosage of the medical fluid is usually controlled through the path of the piston of the injector 110. Gas is compressible, thus causing imprecise changes in the amount of medical fluid in the injector. Also, the amount of gas trapped in the injector 110 must be small, otherwise there is a risk of it being injected into the common line 102.

[0014] Thus, what is needed is an injection system that can quickly vent gas whenever it is present within the injection apparatus without requiring any operator intervention. Summary of the Invention [Means for solving the problem]

[0015] An injection device for injecting a medicinal liquid from a medicinal liquid container into a medical tube, comprising: a body defining a longitudinally extending interior space between an upper end of the body and a lower end of the body, the lower end of the body including a medical tubing interface through which medical fluid can enter the interior space from a medical fluid container and exit the interior space for infusion into a medical tubing; a piston disposed within the interior volume and configured to move longitudinally within the interior volume, the piston defining an upper volume and a lower volume of the interior volume, the lower volume being configured to receive the medicinal liquid; an exhaust passage that traverses the piston in a longitudinal direction from a lower space to an upper space of the internal space; a selector disposed in the exhaust path between a lower portion of the exhaust path and an intermediate portion of the exhaust path, the lower portion of the exhaust path being connected to a lower space, the selector configured to selectively allow gas to pass through the selector and travel along the exhaust path from the lower portion to the intermediate portion of the exhaust path, and the selector configured to selectively prevent chemical liquid from passing through the selector and traveling along the exhaust path from a lower space to an upper space of the interior space; a purge valve disposed in the exhaust path between a middle portion of the exhaust path and an upper portion of the exhaust path and configured to move between a blocking configuration in which the purge valve closes the exhaust path and a passing configuration in which the purge valve keeps the exhaust path open, the passing configuration of the purge valve requiring excess pressure in the middle portion of the exhaust path caused by a piston moving toward a lower end of the body; An injection device is proposed, comprising:

[0016] The present invention allows gas to be evacuated from the injection device every time the piston moves to push medical fluid into the medical tubing, therefore purging is performed automatically without any operator intervention, ensuring that gas is not injected into the medical tubing.

[0017] Other preferred, but non-limiting, aspects of the present invention are as follows, either separately or in any technically feasible combination: the purge valve is configured to be in a shutoff configuration when the piston moves toward the upper end of the body; a lower portion of the exhaust path configured to receive both the chemical liquid and the gas, and an intermediate portion and an upper portion of the exhaust path configured to receive only the gas; the head space is configured to be maintained at a constant reference pressure, and the overpressure in the intermediate portion of the exhaust path corresponds to a gas pressure above the reference pressure; the piston includes a lower interface defining a lower space of the interior space, the lower interface including an exhaust passage inlet opening to a highest portion of the lower interface; The lower interface has a convex surface when viewed from the lower space of the internal space, and the inlet of the exhaust path opens at the center of the lower interface, or the lower interface has a concave surface when viewed from the lower space of the internal space, and the inlet of the exhaust path opens at the periphery of the lower interface; the selector is a float configured to float on the chemical solution and disposed within a cavity, the cavity including at least a passageway belonging to an exhaust path, the float configured to move within the cavity along a longitudinal direction between a blocking configuration in which the float blocks the passageway, thereby closing the exhaust path, and an open configuration in which the float is disposed away from the passageway, thereby opening the exhaust path; The float has at least one obstruction portion and a floating portion, the obstruction portion is configured to block the passage, and the floating portion has an enlarged portion relative to a maximum width portion of the obstruction portion; the float is configured to block the passageway at two distinct areas that contact the seat defining the passageway; the selector is a membrane extending across the exhaust path, said membrane being hydrophobic and configured to allow gas to pass therethrough and prevent the passage of chemicals therethrough; The membrane is disposed within a cavity and a support is disposed within the cavity against an upper side of the membrane to mechanically support the membrane, the support allowing gas to pass through the membrane and through the support.

[0018] The present invention also provides an injection system comprising: An injection device according to any of the embodiments; a first connector configured to be connected to a drug solution container; a medical fluid supply line configured to connect the first connector to the medical tubing interface for supplying the medical fluid to the infusion system; a common line configured to be connected to the medical tubing interface and the patient line for injecting a medical fluid into the patient line; The present invention relates to an injection system, including:

[0019] Preferably, the overpressure corresponds to a pressure in an intermediate portion of the exhaust path exceeding a reference pressure in the headspace by at least a first pressure threshold; the common line includes a threshold valve having a second pressure threshold; The first pressure threshold is lower than the second pressure threshold.

[0020] The present invention also provides a process for operating the injection device of any of the embodiments, the injection device being held with the top end of the body facing up and the bottom end of the body facing down, the process comprising: a filling step in which the piston moves longitudinally within the interior space toward the upper end of the body to force medical fluid and gas from the medical fluid container through the medical tubing interface into the interior space and the purge valve is in a shutoff configuration; a purge step in which the piston moves longitudinally within the interior space toward the lower end of the body, and while the selector holds the liquid drug within the lower space, gas is vented from the lower space of the interior space to the upper space through an exhaust path that crosses the piston, and the purge valve is in a pass-through configuration; The present invention relates to a process comprising the steps of:

[0021] Other aspects, objects and advantages of the present invention will become more apparent on reading the following detailed description of preferred embodiments of the invention, given by way of non-limiting example and made with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is an overall view of an injection system to which two liquid drug containers are connected. [Diagram 2] 13A-13C are cross-sectional views of the piston of an injection device according to a possible non-limiting embodiment in which the selector is a float during the filling step before purging. [Diagram 3] 13 is a cross-sectional view of a piston of an injection device according to a possible non-limiting embodiment in which the selector is a float during the start of a purge. [Figure 4] 13 is a cross-sectional view of the piston of an injection device according to a possible non-limiting embodiment in which the selector is a float at the end of the purge. FIG. [Diagram 5] 13 is a cross-sectional view of a piston of an injection device according to a possible non-limiting embodiment, during the injection step after purging, in which the selector is a float. FIG. [Figure 6] FIG. 1 is a cross-sectional view of a float that functions as a selector, according to a possible non-limiting embodiment. [Figure 7a] 13A-13C are cross-sectional views of a float of an injection device according to a possible non-limiting embodiment during a two-stage blockage of the exhaust path. [Figure 7b] 13A-13C are cross-sectional views of a float of an injection device according to a possible non-limiting embodiment during a two-stage blockage of the exhaust path. [Figure 7c] 13A-13C are cross-sectional views of a float of an injection device according to a possible non-limiting embodiment during a two-stage blockage of the exhaust path. [Figure 8] 13A-13C are cross-sectional views of the piston of an injection device according to a possible non-limiting embodiment, during a filling step before purging, in which the selector is a membrane. [Figure 9] 13A-13C are cross-sectional views of the piston of an injection device according to a possible non-limiting embodiment in which the selector is a membrane during the start of a purge. [Figure 10] 13A is a cross-sectional view of the piston of an injection device according to a possible non-limiting embodiment in which the selector is a membrane, at the end of the purge. FIG. [Figure 11] 13A-13C are cross-sectional views of the piston of an injection device according to a possible non-limiting embodiment, during the injection step after purging, in which the selector is a membrane. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The injection device of the present invention may be used in injection system 100, as previously described in connection with Figure 1. Other than injection device 1, injection system 100 will not be described further.

[0024] 2-5 and 8-11, the infusion device 110 includes a body 2 defining an interior space 4 extending longitudinally between an upper end of the body 2 and a lower end of the body 2, the lower end of the body having a medical tubing interface 112 through which a medical fluid can enter the interior space 4 from a medical fluid container 104 and can exit said interior space 4 to be infused into the common line 102. In contrast to previous infusion devices, the infusion device 110 according to the present invention is configured to remain in a position with the medical tubing interface 112 facing down. Spatial terms such as "lower", "upper", "below", "up", "higher", "highest" and the like should be understood as defining generally accepted relative positions with respect to the vertical direction, i.e. the direction of local earth gravity. This is because the gas and medical fluid are subjected to gravity, and the present invention utilizes gravity for proper gas evacuation. As a result, in use, the lower end of the body 2 is located below the upper end of the body 2. The body 2 is typically a hollow cylindrical body, also called a barrel, made of, for example, glass or plastic material.

[0025] The injection device 110 also includes a piston 6 arranged in the internal space 4 and configured to move in the internal space 4, i.e. between the upper end of the body 2 and the lower end of the body 2, along the longitudinal direction. The piston 6 delimits an upper space 4b and a lower space 4a of the internal space. The lower space 4a is configured to receive a medicinal liquid, whereas the upper space 4b is not intended to receive a liquid. The piston 6 provides a hermetic seal between the upper space 4b and the lower space 4a. For this purpose, the piston 6 is provided with at least one peripheral seal 8, 10, for example made of rubber, preferably two peripheral seals 8, 10 at different heights along the longitudinal direction. Each peripheral seal 8, 10 presses against the wall of the body 2 to ensure a tight seal. As in the illustrated example, the peripheral seals 8, 10 can be quad rings, but can also be O-rings, for example.

[0026] Due to the sealing provided by the piston 6, the pressure may be significantly different between the upper space 4b and the lower space 4a of the internal space 4. The pressure in the upper space 4b is kept at a reference pressure that is approximately constant and substantially independent of the movement of the piston 6. This reference pressure is typically atmospheric pressure, e.g. the pressure of the environment of the system. Preferably, the upper end of the body 2 is at least partially open so that the pressure in the upper space 4b corresponds to atmospheric pressure, regardless of the movement of the piston 6. Conversely, the pressure in the lower space 4a of the internal space 4 depends on the contents of said lower space 4a and the movement of the piston 6. In the following description, an overpressure is a pressure higher than the reference pressure, and a vacuum pressure is a pressure lower than the reference pressure.

[0027] The piston 6 is attached to the piston rod 12, for example by a protrusion 14 at the top of the piston 6 which is engaged in said piston rod 12. The piston rod 14 is driven by a syringe 108 to move the piston 6 along the longitudinal direction in the interior space 4. The piston 6 can be formed by several parts assembled together. In the illustrated example, the piston 6 has a lower part 6a, a middle part 6b and an upper part 6c. Connectors such as screws 16 may be used to assemble the parts of the piston.

[0028] The piston 6 has an exhaust path arranged therein. The path longitudinally crosses the piston 6 from the lower space 4a to the upper space 4b of the interior space 4. The exhaust path is intended to exhaust gas present in the lower space 4a into the upper space 4b. Typically, the exhaust path is not linear and can be open or closed at different points depending on the components of the piston 6, as will be explained below. More specifically, the exhaust path includes a lower portion 17a, a middle portion 17b, and an upper portion 17c. The lower portion 17a of the exhaust path is connected to the lower space 4a, whereas the upper portion 17c of the exhaust path is connected to the upper space 4c. The middle portion 17b is between the lower portion 17a and the upper portion.

[0029] The piston 6 includes a lower interface 18 that defines the boundary of the lower space 4a of the internal space 4, said lower interface 18 having an inlet 20 of the exhaust path. Preferably, the inlet 20 opens at the highest part of the lower interface 18 with respect to the lower interface 18 in order to properly exhaust all gas present in the lower space 4a of the internal space without gas being trapped in the lower space. Preferably, the lower interface 18 has a surface with an apex facing towards the upper end of the body, and the inlet 20 of the exhaust path opens at said apex. For example, the lower interface 18 has a convex surface when viewed from the lower space 4a of the internal space, and the inlet 20 of the exhaust path opens at the center of said lower interface 18, as in the example shown. For example, the surface of the lower interface 18 may correspond to the surface of an upwardly facing cone, a truncated cone or a pyramid. Alternatively, the lower interface 18 may have a concave surface when viewed from the lower space 4a of the internal space, and the inlet 20 of the exhaust path opens at the periphery of said lower interface 18. For example, the lower interface 18 may have a groove disposed about the periphery of the lower interface 18, and the exhaust path inlet 20 may open into the groove.

[0030] The piston 6 includes a purge valve 22 arranged in the exhaust path between the middle portion 17b of the exhaust path and the upper portion 17c of the exhaust path. The purge valve 22 is configured to move between a blocking configuration in which the purge valve 22 closes the exhaust path and a passing configuration in which the purge valve 22 keeps said exhaust path open. The passing configuration of the purge valve 22 requires an overpressure in the middle portion 17b of the exhaust path relative to a reference pressure in the upper space 4b, caused by the piston 6 moving towards the lower end of the body 2. Since the upper space 4b is at a reference pressure (e.g. atmospheric pressure), overpressure means a pressure above the reference pressure. More precisely, the overpressure required for the passing configuration of the purge valve 22 corresponds to a pressure in the middle portion 17b that exceeds the reference pressure in the upper space 4b and the upper portion 17c of the exhaust path by at least a first pressure threshold. The purge valve 22 is configured to be in the blocking configuration when the piston 6 moves towards the upper end of the body 2. This is because no overpressure with respect to the reference pressure in the head space 4b occurs in the intermediate portion 17a, but instead a vacuum pressure, ie a pressure lower than the reference pressure, occurs.

[0031] The piston 6 also includes a selector 24, 60 disposed in the exhaust path between the lower portion 17a of the exhaust path and the middle portion 17b of the exhaust path. The selector 24, 60 is configured to selectively allow gas to pass through said selector 24, 60 and to move along the exhaust path from the lower portion 17a to the middle portion 17b of the exhaust path. The selector 24, 60 is configured to selectively prevent the medicinal liquid from passing through said selector 24, 60 and to move along the exhaust path from the lower portion 17a to the middle portion 17b of the exhaust path, and thus from moving along the exhaust path from the lower space 4a to the upper space 4b of the interior space. As a result, the lower portion 17a of the exhaust path is a mixing portion configured to receive both the medicinal liquid and the gas, and the middle portion 17b and the upper portion 17c are gas portions configured to receive only the gas.

[0032] The purge valve 22 is disposed above the selectors 24, 60 in the longitudinal direction from the lower space 4a to the upper space 4b of the internal space. Therefore, the purge valve 22 is disposed in the gas portion of the exhaust path and does not come into contact with the liquid at all.

[0033] In the shutoff configuration, the purge valve 22 seals the exhaust hole 26 between the middle portion 17b and the top portion 17c of the exhaust path. In the through configuration, the purge valve 22 opens said exhaust hole 26. In the illustrated example, two exhaust holes 26 are seen between the middle portion 17b and the top portion 17c of the exhaust path. More or fewer exhaust holes 26 can be provided, as long as they can be sealed by the purge valve 22.

[0034] Preferably, as shown in the illustrated embodiment, the purge valve 22 is an umbrella valve having a diaphragm-shaped sealing disk 22a and a stem 22b. The stem 22b is engaged in a hole 28 arranged in the fixed part of the piston 6 and presents an enlarged lower part with a cross section larger than that of the hole 28, thereby fixing the purge valve 22. The diaphragm-shaped sealing disk 22a is arranged above at least one exhaust hole 26 that is part of the exhaust path and that delimits the upper part 17c of the exhaust path from the middle part 17c. The umbrella valve can be deformable (e.g. due to deformation of the stem) and / or can slidably move along the hole 28 arranged in the fixed part of the piston 6 to change its configuration. In the passing configuration, the sealing disk 22a is away from the exhaust hole 26 due to the higher gas pressure in the middle part 17b, thereby allowing gas to pass through said exhaust hole 26. In the blocking configuration, the sealing disk 22a is forced against the exhaust hole 26 due to the higher gas pressure in the upper portion 17c of the exhaust path, thereby sealing said exhaust hole 26 and closing the exhaust path. For example, the umbrella valve can be made of a rubber-type elastomer or of silicone.

[0035] The selector 24, 60 may be, for example, a float 24 configured to float on a drug solution or a hydrophobic membrane 60. A process for operating an injection device with a float 24 as a selector will now be described with reference to Figures 2 to 7, and then a process for operating an injection device with a membrane 60 as a selector will be described below with reference to Figures 8 to 11. With the exception of the selectors 24, 60, the features of the injection device 110 and the process features described below may be applied to any of the embodiments.

[0036] (The selector is a float.) 2 shows the injection device 110 before purging, e.g. during a filling step in which the injection device 110 is filled with drug solution and unwanted gas. During this filling step, the piston rod 12 is driven upwards, e.g. by the injector 108 acting on said piston rod 12, thereby moving the piston 6 longitudinally in the interior space 4 towards the upper end of the body 2, i.e. upwards. The lower space 4a expands, as a result of which the gas pressure in said lower space 4a falls below a reference gas pressure in the upper space 4b, e.g. atmospheric pressure.

[0037] Since the selector 24 allows gas to move from the lower portion 17a to the middle portion 17b of the exhaust path, the pressure drop in the lower space 4a is also seen in the lower portion 17a and the middle portion 17b of the exhaust path. However, since the purge valve 22 requires an overpressure in the middle portion 17b of the exhaust path to be in the passing configuration, the purge valve 22 is held in the blocking configuration. More precisely, the purge valve 22 is depressed to seal the exhaust hole 26, thereby closing the exhaust path in the blocking configuration.

[0038] The expansion of the lower space 4a combined with the closing of the exhaust path by the purge valve 22 effectively creates a vacuum pressure in the lower space 4a, i.e. a pressure lower than the reference pressure. The pressure in the lower space 4a drops until it reaches the opening pressure of the first tube valve 130, which is, for example, 0.2-0.5 bar lower than the reference pressure. The opening of the first tube valve 130 creates a suction of the drug solution to compensate for this vacuum pressure in the lower space 4a. The drug solution fills the lower space 4a through the filling line 114 connected to the drug solution container 104. Any gas present in the tube is also sucked into the lower space 4a.

[0039] Gradually, as the lower space 4a is filled with the drug solution and gas, the pressure in the lower space 4a rises and approaches atmospheric pressure. When the pressure in the lower space 4a reaches the closing pressure (substantially similar to the opening pressure) of the first tube valve 130, the first tube valve 130 closes and filling is stopped. At the end of the filling step, the lower space 4a is filled with an amount of gas 32 that exceeds the amount of drug solution 34. Because the pressure rise was stopped by the closing of the first tube valve 130 before the vacuum pressure was fully compensated, the gas pressure in the lower space 4a is still lower than the gas pressure in the upper space 4b. As a result, the purge valve 22 maintains the shutoff configuration.

[0040] As explained above, after filling the injection device 110, the gas in the lower space 4a must be evacuated during purging. This purging is performed by driving the piston 6 downwards, as shown in FIG. 3. The piston 6 moves longitudinally in the inner space 4 towards the lower end of the body 2. The lower space 4a contracts and the gas pressure rises in the lower space 4a until the pressure difference between the gas pressure in the intermediate part 17b, which is still in communication with the lower space 4a, and the reference gas pressure in the upper space 4b is higher than the opening pressure threshold of the purge valve 22, i.e. until the pressure difference reaches the first pressure threshold.

[0041] As described above, the purge valve 22 is configured to transition to the through configuration in response to an overpressure in the lower space 4a exceeding the reference pressure in the upper space 4b by at least an opening pressure threshold of the purge valve 22 (e.g., a pressure difference between the overpressure and the reference pressure of 20-100 mbar). Thus, the purge valve 22 transitions to the through configuration, thereby opening the exhaust path. In the illustrated example, the sealing disk 22a moves in a direction away from the exhaust hole 26, thereby unsealing said exhaust hole 26.

[0042] Gas is exhausted from the lower space 4a of the interior space 4 through an exhaust path that crosses the piston 6 and into the upper space 4b. More specifically, the gas enters the exhaust path through the inlet 20, then travels along the lower portion 17a of the exhaust path, then along the middle portion 17b of the exhaust path, through the exhaust hole 26, and finally along the upper portion 17c to reach the upper space. This is shown by the dotted arrows in Figure 3.

[0043] When the piston 6 moves downwards while the gas is being exhausted through the exhaust path, the piston reaches the amount of liquid medicine in the lower space 4a. More specifically, the lower interface 18 contacts the liquid medicine and the gas is pushed back towards the inlet 20 of the exhaust path because the inlet 20 opens at the highest part of the lower interface 18. Therefore, the gas is exhausted from the lower space 4a before the liquid medicine reaches the inlet 20 of the exhaust path. When all the gas is exhausted, the liquid medicine enters through the inlet 20 of the lower interface 18 of the piston 6 and fills the lower part 17a of the exhaust path.

[0044] As shown, the lower portion 17a of the exhaust path can include a cavity 36 in which the selector 24 is disposed, and the chemical solution begins to fill the cavity 36. The selector is a float 24 configured to float on the chemical solution, and the cavity 36 is configured to allow the float 24 to move up and down along a longitudinal direction within the cavity 36. The cavity 36 includes at least a passageway 38 that forms a boundary between the lower portion 17a and the middle portion 17b of the exhaust path. The passageway 38 is disposed at an upper portion of the cavity 36. The float 24 is configured to move along a longitudinal direction within the cavity 36 between a blocking configuration in which the float 24 blocks the passageway 38, thereby closing the exhaust path, and an open configuration in which the float 24 is disposed away from the passageway 36, thereby keeping the exhaust path open and unblocked.

[0045] More precisely, when cavity 36 fills with gas 32, float 24 remains at the bottom of cavity 36, keeping passageway 38 open and thus keeping the exhaust path unblocked. When the chemical solution reaches cavity 36, float 24 begins to float on the chemical solution and therefore moves upwards, carried by chemical solution 34 according to the upward buoyant force that the chemical solution exerts on the float (Archimedes' principle). Under this force, float 24 moves upwards until it reaches the top of cavity 36 and blocks passageway 38.

[0046] The passage 38 is defined by a periphery that faces the float 24 and forms a seat 40 for said float 24. The float closes the passage 38 by pressing against the seat. The seat 40 is made, for example, of metal or of plastic, such as thermoplastic polyurethane, polyoxymethylene, polycarbonate, polyvinyl chloride, etc. Advantageously, the seat 40 is made of a material having a modulus of elasticity higher than 2500 MPa (megapascals). Preferably, the seat 40 has a cross section that decreases in the direction of the intermediate portion 17b of the exhaust path, for example the shape of the seat 40 is at least partially a hollow truncated cone. A reinforcing element 42, such as a washer, can be provided on the seat 40 to reinforce it, especially when said seat is made of a highly deformable material.

[0047] As shown in the example of FIG. 6, the float 24 has at least an obstruction 24a configured to block the passage 38. Typically, the passage 38 has a circular cross section, and the obstruction 24a of the float 24 also has a circular cross section. For example, the obstruction 24a of the float 10 may have an at least partially ellipsoidal shape, or a spherical or pine-like conical shape. For example, the float 24 can simply be a ball. Preferably, the obstruction 24 of the float is coated with a deformable material for better sealing of the passage 38 when the float 24 is pressed against the seat 40.

[0048] Preferably, the float 24a has a floating part 24b with an enlarged portion relative to the widest portion of the obstruction part 24a, said floating part 24b supporting the obstruction part 24a. The float can be constructed in two parts as in FIG. 6, or it can be constructed in a single piece including the obstruction part 24a and the floating part 24b. The obstruction part 24a of the float 24 is, for example, a ball. The floating part 24b of the float 24 has a larger diameter than the largest diameter of the obstruction part 24a, i.e. the ball part, of the float. The larger diameter of the floating part 24b of the float 24 (perpendicular to the longitudinal direction) makes the float 24 more responsive to the small force exerted on it by the medical solution 34. This enhanced response allows the medical solution to push the float 24 up as soon as it reaches the float 24, thus ensuring that the medical solution cannot reach the passage 38 before it is blocked by the float 24.

[0049] When the chemical liquid 34 comes into contact with the float 24, for example with the floating part 24b of the float 24, the float 24 starts to float and therefore moves upwards until it reaches the seat 40. The shape of the float 24 and the shape of the seat 40 are adapted so that a continuous seal is formed when the float 24 presses against the seat 40. The passage 38 is now blocked and neither gas nor chemical liquid can pass through the blocked passage 38. A small amount of gas may be trapped in the cavity 36 between the blocked passage 38 and the surface of the chemical liquid 34, i.e. in the lower part of the exhaust path. This small amount of gas makes it possible to keep the seat dry and to prevent material deposition on the seat 40. The small amount may be, for example, an amount of less than 10 ml at atmospheric pressure. This small amount of air may be sufficient to dry the float 24. The density of the float 24 and the complementary shapes of the occlusion 24a and the seat 40 are selected to minimize the amount of trapped air while keeping the surface of the chemical solution away from the seat 40. For example, the cross section of the seat may decrease towards the intermediate portion 17b of the exhaust path.

[0050] Once the passage 38 is blocked, gas cannot escape the overpressure in the lower part 17a of the exhaust path and reach the middle part 17b. As a result, the pressure in the middle part 17b above the blocked passage 38 drops until the difference between the pressure in the middle part 17b, which is slightly higher than the reference pressure since the head space 4b is at said reference pressure, and the reference pressure reaches the closing pressure threshold of the purge valve 22. For example, the closing pressure threshold of the purge valve 22 can correspond to a positive pressure difference between the pressure in the middle part 17b and the reference pressure of 20 to 100 mbar. Preferably, the closing pressure threshold and the open-close threshold are substantially the same, but can also be different. As a result, the purge valve 22 is now closed in the shutoff configuration (FIG. 5). In this example, the sealing disk 22a covers the exhaust hole 26. The purge step is finished. A small amount of gas 32 with a residual overpressure (i.e. slightly higher than the reference pressure) is held in the middle part 17b. The residual overpressure is not high enough to force the purge valve 22 to open the exhaust 26. This residual overpressure ensures that air at atmospheric pressure coming from the headspace 4b cannot enter the intermediate portion 17b of the exhaust path, thus preventing non-sterile air from entering the sterile area where the medical fluid circulates.

[0051] The process may include a supplemental fill step that occurs after the purge step and before the injection step. The supplemental fill step allows the lower volume 4a to be filled with the exact prescribed amount of drug solution 34, which was not possible in the first fill step due to the amount of gas 32 that caused an inaccurate measurement of the amount (usually based on the advancement of the piston 36).

[0052] The process may include an injection step, in which the piston moves longitudinally in the internal space toward the lower end of the body, and the medical solution flows out of said lower space of the internal space to be injected into the medical tube. When the exhaust path is closed, the pressure in the lower space 4a increases when the piston 6 is pressed down. When the pressure in the lower space 4a reaches the opening pressure of the second tube valve 140, the second tube valve 140 opens, and the medical solution 34 flows out of the lower space 4a, travels through the common line 102, and can reach the patient line 116. Thus, the medical solution can be injected without gas. During injection, the float 24 comes into contact with the medical solution.

[0053] It should be noted that the opening pressure threshold (i.e. the first pressure threshold) of the purge valve 22 is lower than the opening pressure threshold (the second pressure threshold) of the second tube valve 140, so that when gas is exhausted, the purge valve 22 opens before the second tube valve 140 opens. However, during this injection step, the blocking of the passage 38 by the selector (float 24) means that pressure builds up in the lower space 4a but not in the isolated intermediate portion 17b of the exhaust path. The purge valve 22 is therefore held in a shutoff configuration.

[0054] As a variant illustrated in Figures 7a, 7b and 7c, the selector can be a float 50 with a two-stage blockage of the exhaust path. The float 50 is configured to block the passage 38 in two distinct areas in contact with the seat 40 that defines the passage 38. For this purpose, the float 50 includes a first blockage 50a and a second blockage 50b, which are arranged such that when the float 50 rises to block the passage 38, first the first blockage 50a cooperates with the first seat 40 to form a first seal, and then the second blockage 50b cooperates with the seat 40 to form a second seal.

[0055] Preferably, the first occlusion 50a faces the passage 38, whereas the second occlusion 50b has a sealing portion 52 arranged to cooperate with the seat 40 surrounding the first occlusion 50a (in a projection in a plane perpendicular to the longitudinal direction). As a result, when the float 50 rises, the second sealing portion surrounds the first sealing portion. In the illustrated example, the first occlusion 50a of the float 50 can be like the occlusions already described and can be a ball as shown. The second occlusion 50b of the float 50 can correspond to the floating portion 24b of the float previously described. The second occlusion 50b can be further enlarged with respect to the first occlusion 50a, but now also has at least one sealing portion 52 projecting upwards around the periphery of the upper part. Preferably, the highest point of sealing portion 52 is below the highest point of first occlusion portion 50a so that the first seal occurs before the second seal. As previously mentioned, it should be noted that float 50, although illustrated as a two piece float, could be a one piece float.

[0056] The seat 40 can be adapted to this type of float 50. The seat 40 can define two wall portions of the passage 38, corresponding to a first seat 40a and a second seat 40b. The second seat 40b surrounds the first seat 40a (in a projection in a plane perpendicular to the longitudinal direction). Preferably, the first seat 40a is deformable (e.g., with a hardness of 20 to 30 ShA (Shore A scale)) and allows the float 50 to continue to rise so that it can contact the second seat 40b after deformation of the first seat 40a.

[0057] In FIG. 7a, the float 50 is away from the seats 40a, 40b and does not block the passage 38. Gas can pass through the passage 38 to be vented into the upper space 4b. In FIG. 7b, the float 50 starts to float on the chemical liquid and therefore moves upwards towards the seats 40a, 40b. The first occlusion 50a of the float contacts the first seat 40a and creates a first seal, as explained above. The passage 38 is blocked by the first occlusion. As the piston 6 moves further downwards, the pressure in the cavity 36 of the lower part 17a of the exhaust path increases and the chemical liquid fills the cavity 36. The float 50 remains pressed against the first seat 40a, which is deformed by the force exerted by the float 50. The float 50 can therefore move upwards and the sealing part 52 of the second occlusion 50b contacts the second seat 40b. A second occlusion is performed as shown in FIG. 7c.

[0058] In this variation, a large amount of gas is trapped under the blocked passageway and the second seal ensures that the drug solution does not come into contact with the first occlusion 50a, which is kept dry and free of any contamination. The first occlusion 50a is kept clean and ensures that the first seal is in place.

[0059] (The selector is a membrane) Now, with reference to Figures 8 to 11, a process for operating the injection device 110 with the membrane 60 as a selector will be described. The membrane 60 extends across the exhaust path and defines the lower and middle parts 17a and 17b of the exhaust path. The membrane 60 is configured to be hydrophobic and to allow gas to pass while preventing the drug solution from passing. In this example, the membrane 60 is arranged in a cavity having a larger cross section than the inlet 20 of the exhaust path (orthogonal to the longitudinal direction). This is not necessary, and the inlet 20 can have a larger cross section than the cavity 36. However, a larger cavity accelerates purging, since it increases the surface of the membrane 60 through which gas can pass.

[0060] 8 shows the injection device 110 before purging, e.g. during a filling step in which the injection device 110 is filled with drug solution and unwanted gas. During this filling step, the piston rod 12 is driven upwards, e.g. by the injector 108 acting on said piston rod 12, thereby moving the piston 6 longitudinally in the interior space 4 towards the upper end of the body 2, i.e. upwards. The lower space 4a expands, as a result of which the gas pressure in said lower space 4a falls below the gas pressure in the upper space 4b, e.g. atmospheric pressure.

[0061] Since the membrane 60 allows gas to move from the lower portion 17a to the middle portion 17b of the exhaust path, the pressure drop in the lower space 4a is also seen in the lower portion 17a and the middle portion 17b of the exhaust path. However, since the purge valve 22 requires an overpressure in the middle portion 17b of the exhaust path to be in the passing configuration, the purge valve 22 is held in the blocking configuration. More precisely, the purge valve 22 is depressed to seal the exhaust hole 26, thereby closing the exhaust path.

[0062] The expansion of the lower space 4a combined with the closing of the exhaust path by the purge valve 22 effectively creates a vacuum pressure in the lower space 4a, i.e. a pressure lower than the reference pressure. The pressure drops until it reaches the opening pressure of the first tube valve 130, which is, for example, 0.2-0.5 bar lower than the reference pressure. The opening of the first tube valve 130 creates a suction of the drug solution to compensate for this vacuum pressure in the lower space 4a. The drug solution fills the lower space 4a through the filling line 114 connected to the drug solution container 104. The gas present in the tube is also sucked into the lower space 4a.

[0063] Gradually, as the lower space 4a is filled with a certain amount of the liquid medicine 34 and a certain amount of the gas 32, the pressure in the lower space 4a increases and approaches atmospheric pressure. When the pressure in the lower space 4a reaches the closing pressure of the first tube valve 130 (substantially similar to the opening pressure), the first tube valve 130 closes and the filling is stopped. At the end of the filling step, the lower space 4a is filled with an amount of the gas 32 that exceeds the amount of the liquid medicine 34. Because the pressure increase was stopped by the closing of the first tube valve 130 before the vacuum pressure was fully compensated, the gas pressure in the lower space 4a is still lower than the gas pressure in the upper space 4b. As a result, the purge valve 22 maintains the shut-off configuration.

[0064] As explained above, after filling the injection device 110, the gas in the lower space 4a must be evacuated during purging. This purging is performed by driving the piston 6 downwards, as shown in FIG. 9. The piston 6 moves longitudinally in the inner space 4 towards the lower end of the body 2. The lower space 4a contracts and the gas pressure rises in the lower space 4a until the pressure difference between the gas pressure in the middle part 17b, which is still in communication with the lower space 4a, and the gas pressure in the upper space 4b is higher than the opening pressure threshold of the purge valve 22, i.e. until the pressure difference reaches the first pressure threshold.

[0065] As described above, the purge valve 22 is configured to transition to the through configuration in response to an overpressure in the lower space 4a exceeding the reference pressure in the upper space 4b by at least an opening pressure threshold of the purge valve 22 (e.g., a pressure difference between the overpressure and the reference pressure of 20-100 mbar). Thus, the purge valve 22 transitions to the through configuration, thereby opening the exhaust path. In the illustrated example, the sealing disk 22a moves in a direction away from the exhaust hole 26, thereby unsealing said exhaust hole 26.

[0066] Gas is exhausted from the lower space 4a of the interior space 4 through an exhaust path that crosses the piston 6 to the upper space 4b. More specifically, the gas enters the exhaust path through the inlet 20, then travels along the lower portion 17a of the exhaust path, passes through the membrane 60, then travels along the middle portion 17b of the exhaust path, through the exhaust hole 26, and finally travels along the upper portion 17c to reach the upper space 4b. This is shown by the dotted arrows in Figure 9.

[0067] When the piston 6 moves downwards while the gas is being exhausted through the exhaust path, the piston reaches the amount of liquid medicine in the lower space 4a. More specifically, the lower interface 18 contacts the liquid medicine, and since the inlet 20 opens at the highest part of the lower interface 18, the gas is pushed back towards the inlet 20 of the exhaust path. Therefore, the gas is exhausted from the lower space 4a before the liquid medicine reaches the inlet 20 of the exhaust path. When all the gas is exhausted, the liquid medicine enters from the inlet 20 of the lower interface 18 of the piston 6 and fills the lower part 17a of the exhaust path.

[0068] As shown, the membrane 60 can be placed in the cavity 36, and the medicinal liquid begins to fill the cavity 36 while the gas leaks from the lower part of the cavity 36 belonging to the lower part 17a of the exhaust path and reaches the upper part of the cavity 36 belonging to the middle part 17b of the exhaust path. The membrane 60 is configured to allow the gas to pass while preventing the medicinal liquid from passing. The membrane 60 is a hydrophobic material and can be made of, for example, PET (polyethylene terephthalate), ABS (acrylonitrile butadiene styrene), PA (polyamide), or other plastic materials, or medical stainless steel. The membrane 60 can be coated with, for example, PTFE (polytetrafluoroethylene), ePTFE (expanded polytetrafluoroethylene), or other hydrophobic materials.

[0069] The membrane 60 may be characterized by the air permeability of the membrane 60 and the pore size of the membrane 60. In particular, the membrane 60 may have a pore size of 5 l / m or less at 120 Pa·s. 2This allows for very low air permeability, such as 0.1 / sec. Low air permeability allows for small pore sizes in the membrane. For example, the pore sizes of membrane 60 may range from about 0.01 to 0.25 microns. Optionally, membrane 60 may have small pores, such as 0.07 microns or less. For example, membrane 60 may have a tissue thickness of about 200 microns.

[0070] The membrane 60 prevents the chemical liquid from passing when it comes into contact with the membrane 60, and the chemical liquid is blocked at the bottom of the cavity 36 belonging to the lower part 17a of the exhaust path. Since gas can no longer reach from the lower part 17a into the middle part 17b, while still leaking from said middle part 17b of the exhaust path into the upper space 4b, the pressure in the middle part 17b of the exhaust path drops until the difference between the pressure in the middle part 17b, which is slightly higher than the said reference pressure, and the reference pressure reaches the closing pressure threshold of the purge valve 22, since the upper space 4b is at the reference pressure. For example, the closing pressure threshold of the purge valve 22 can correspond to a positive pressure difference between the pressure in the middle part 17b and the reference pressure of 20 to 100 mbar. Preferably, the closing pressure threshold and the open-close threshold are substantially the same, but can also be different. As a result, the purge valve 22 is now closed (FIG. 11) and the sealing disk 22a covers the exhaust hole 26. The purge is now finished.

[0071] The process may include a supplemental fill step that occurs after the purge step and before the injection step. The supplemental fill step allows the lower volume 4a to be filled with the exact prescribed amount of drug solution 34, which was not possible in the first fill step due to the amount of gas 32 that caused an inaccurate measurement of the amount (usually based on the advancement of the piston 36).

[0072] The process may include an injection step in which the piston moves longitudinally in the internal space toward the lower end of the body and the medical fluid flows out of said lower space of the internal space to be injected into the medical tube. If the exhaust path is closed, the pressure in the lower space 4a increases when the piston 6 is pressed down. When the pressure in the lower space 4a reaches the opening pressure of the second tube valve 140, the second tube valve 140 opens and the medical fluid 34 can flow out of the lower space 4a, travel through the common line 102, and reach the patient line 116. Thus, the medical fluid can be injected without gas. It should be noted that the opening pressure threshold (i.e., the first pressure threshold) of the purge valve 22 is lower than the opening pressure threshold (the second pressure threshold) of the second tube valve 140, so that the purge valve 22 opens before the second tube valve 140 opens when the gas is exhausted. Thus, the purge valve 22 is held in the shutoff configuration during the injection step.

[0073] During injection, the membrane 60 comes into contact with the liquid medicine and is subjected to the full injection pressure due to contact with the liquid medicine. The injection pressure may reach values ​​such as 24 bar for an injection rate of 10 cc / sec. The membrane 60 is selected to withstand such high pressures. To help the membrane 60 withstand the mechanical forces exerted by the liquid medicine, a support may be placed in the upper part of the cavity 36, i.e., in the middle part 17b of the exhaust path.

[0074] The support is held against the upper side of the membrane 60 so as to mechanically support the membrane 60. The support is permeable to gas (e.g. air) and of course allows gas to pass through the membrane 60 and through said support. The support may be made of semi-rigid or rigid foam. Optionally, the support may be a plastic perforated plate or a metal strip with micro-holes. For example, the support may be a foam, mesh or grid, preferably made of metal. However, the support may be of any kind, as long as it mechanically supports the membrane without preventing gas from passing through the middle part 17b of the exhaust path.

[0075] Although the present invention has been described with respect to certain preferred embodiments, it is clear that the invention is in no way limited to these embodiments and that the invention encompasses all technical equivalents of the described means and combinations thereof. In particular, it will be clear to a person skilled in the art that various changes and modifications can be made thereto without departing from the scope of the invention as defined in the appended claims.

Claims

1. An injection device for injecting a medicinal liquid from a medicinal liquid container into a medical tube, comprising: a body defining a longitudinally extending interior space between an upper end of the body and a lower end of the body, the lower end of the body including a medical tubing interface through which the medical fluid can enter the interior space from the medical fluid container and exit the interior space for injection into the medical tubing; a piston disposed within the interior space and configured to move along the longitudinal direction within the interior space, the piston defining an upper space and a lower space within the interior space, the lower space being configured to receive the medicinal liquid; an exhaust path that crosses the piston in the longitudinal direction from the lower space to the upper space of the internal space; a selector disposed within the exhaust path between a lower portion of the exhaust path and an intermediate portion of the exhaust path, the lower portion of the exhaust path being connected to the lower space, the selector configured to selectively allow gas to pass through the selector and travel along the exhaust path from the lower portion to the intermediate portion of the exhaust path, and the selector configured to selectively prevent the chemical solution from passing through the selector and traveling along the exhaust path from the lower space to an upper space of the interior space; a purge valve disposed in the exhaust path between the intermediate portion of the exhaust path and an upper portion of the exhaust path and configured to move between a blocking configuration in which the purge valve closes the exhaust path and a passing configuration in which the purge valve keeps the exhaust path open, the passing configuration of the purge valve requiring excess pressure in the intermediate portion of the exhaust path caused by the piston moving toward the lower end of the body. Injection device.

2. The injection device of claim 1 , wherein the purge valve is configured to be in the shutoff configuration when the piston moves toward the top end of the body.

3. 10. The injection device of claim 1, wherein the lower portion of the exhaust path is configured to receive both a chemical liquid and a gas, and the middle and upper portions of the exhaust path are configured to receive only a gas.

4. 2. The injection apparatus of claim 1, wherein the headspace is configured to be maintained at a constant base pressure, and the overpressure in the intermediate portion of the exhaust path corresponds to a gas pressure above the base pressure.

5. The injection device of claim 1 , wherein the piston includes a lower interface that bounds the lower volume of the interior volume, the lower interface including an inlet of the exhaust path that opens into a highest portion of the lower interface.

6. 6. The injection device of claim 5, wherein the lower interface has a convex surface when viewed from the lower space of the internal space, and the inlet of the exhaust path opens at a center of the lower interface, or the lower interface has a concave surface when viewed from the lower space of the internal space, and the inlet of the exhaust path opens at a periphery of the lower interface.

7. 2. The injection device of claim 1, wherein the selector is a float configured to float on the drug solution and disposed within a cavity, the cavity including at least a passageway belonging to the exhaust path, the float configured to move within the cavity along the longitudinal direction between a blocking configuration in which the float blocks the passageway, thereby closing the exhaust path, and an open configuration in which the float is disposed away from the passageway, thereby opening the exhaust path.

8. 8. The injection device of claim 7, wherein the float has at least one occlusion portion and a floating portion, the occlusion portion configured to block the passageway, and the floating portion having an enlarged portion relative to a maximum width portion of the occlusion portion.

9. 8. The injection device of claim 7, wherein the float is configured to block the passageway at two distinct areas that contact a seat that defines the passageway.

10. 10. The injection device of claim 1, wherein the selector is a membrane extending across the exhaust path, the membrane being hydrophobic and configured to allow the gas to pass therethrough and prevent the medical fluid from passing therethrough.

11. 11. The injection device of claim 10, wherein the membrane is disposed within a cavity and a support is disposed within the cavity on an upper side of the membrane to mechanically support the membrane, the support allowing the gas to pass through the membrane and through the support.

12. 1. An injection system comprising: An injection device according to claim 1; a first connector configured to be connected to a drug solution container; a medical fluid supply line configured to connect the first connector to the medical tubing interface to supply the medical fluid to the infusion system; a common line configured to be connected to the medical tube interface and the patient line for injecting the medical fluid into the patient line; Injection system.

13. the overpressure corresponds to a pressure in the intermediate portion of the exhaust path that exceeds a reference pressure in the headspace by at least a first pressure threshold; the common line includes a threshold valve having a second pressure threshold; the first pressure threshold is lower than the second pressure threshold; 13. The injection system of claim 12.

14. 13. A process for evacuating gas from an injection device according to claim 1, comprising the steps of: The injection device is held with the top end of the body up and the bottom end of the body down, the process comprising: a filling step in which the piston moves longitudinally within the interior space toward the upper end of the body to force the medical fluid and gas from the medical fluid container through the medical tubing interface and into the interior space, the purge valve being in the blocking configuration; a purging step in which the piston moves along the longitudinal direction within the interior space toward the lower end of the body, and the gas is vented from the lower space of the interior space to the upper space through the vent path that crosses the piston while the selector holds the chemical solution in the lower space, and the purge valve is in the through configuration; Including, Process.

Images