Electric syringe

Abstract

To provide an electric syringe that realizes stable driving of an electroosmotic flow pump.SOLUTION: An electric syringe comprises: a suction side flow passage part having a flow passage in which driving liquid is stored; and a driving mechanism part having a driving flow passage communicating with the flow passage of the suction side flow passage part. The driving mechanism part includes a pair of electrodes and a porous body sandwiched between the pair of electrodes, and functions as an electroosmotic flow pump. The electric syringe has a tubular relief pipe part whose one end part is connected to a portion between the suction side flow passage part in the driving mechanism part and the porous body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electric syringe for aspirating or discharging a liquid or gas. [Background technology]

[0002] There are electrically operated syringes used for drawing bodily fluids, blood, etc., or for injecting medicinal liquids, etc. into the body (see, for example, Patent Documents 1 and 2). The electrically operated syringe in Patent Document 1 is configured to inject medicinal liquids at a set speed by driving a motor. The electrically operated syringe in Patent Document 2 is configured to perform infusion by driving an electroosmotic flow pump. Patent Document 2 claims that the use of an electroosmotic flow pump makes it possible to miniaturize the device, reduce power consumption, and administer minute amounts of medicinal liquid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-156005 [Patent Document 2] Patent No. 6967797 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when an electroosmotic pump is used as the driving source for a motorized syringe, bubbles are generated in the drive liquid when the negative pressure in the flow path increases due to the operation of the pump. When the generated bubbles grow to a certain size, they can interfere with the operation of the electroosmotic pump, causing the flow of the drive liquid to stop. Therefore, there is a demand for a motorized syringe that can achieve smooth and stable operation of the electroosmotic pump. [Means for solving the problem]

[0005] An electric syringe according to one aspect of the present invention comprises: a suction-side flow path section having a flow path in which a driving liquid is stored; a drive mechanism section having a drive flow path that includes a pair of electrodes and a porous body sandwiched between the pair of electrodes and that communicates with the flow path; and a tubular relief pipe section having one end connected to a section of the drive mechanism section between the suction-side flow path section and the porous body. [Effects of the Invention]

[0006] The present invention has a tubular relief pipe section with one end connected to the section of the drive mechanism between the suction-side flow path section and the porous body, which guides bubbles in that section to the relief pipe section and prevents them from expanding or accumulating. This allows for stable operation of the electroosmotic pump, enabling smooth and uninterrupted suction or discharge of liquid or gas. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view showing an example of the configuration of an electric syringe according to a first embodiment of the present invention. FIG. [Figure 2] FIG. 10 is a perspective view showing a configuration example of a power syringe according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] Embodiment 1 An example of the configuration of the electric injector 100 according to the first embodiment will be described with reference to FIG. 1. As shown in FIG. 1, the electric injector 100 has a suction-side flow path section 10, a drive mechanism section 20, a discharge-side flow path section 30, and an escape tube section 50. The suction-side flow path section 10 is made of, for example, resin, and is a tubular member having a flow path 1c. A driving liquid is stored in the flow path 1c of the suction-side flow path section 10. The discharge-side flow path section 30 is made of, for example, resin, and is a tubular member having a flow path 3c.

[0009] The drive mechanism 20 has a main body 21 made of resin and a drive unit 22 partially or entirely contained within the main body 21. The drive unit 22 includes a pair of electrodes, 2a and 2b, and a porous body 23 sandwiched between the electrodes 2a and 2b. The electrodes 2a and 2b are conductive and contain, for example, a conductive material and rubber. At least a portion of the pair of electrodes (2a, 2b) is covered by the main body 21.

[0010] The porous body 23 is formed of, for example, porous ceramic. The porous body 23 is connected to the flow path of the suction-side flow path section 10 via the electrode 2a, and is permeated with the driving liquid. The porous body 23 is also connected to the flow path of the discharge-side flow path section 30 via the electrode 2b. The porous body 23 is covered by the main body section 21. The drive mechanism section 20 has a driving flow path 22c formed between the downstream end of the suction-side flow path section 10 and the upstream end of the discharge-side flow path section 30, which connects the flow path 1c and the flow path 3c.

[0011] In the drive mechanism 20, a drive liquid is permeated into a porous body 23, and a pair of electrodes (2a, 2b) are arranged at positions facing each other across the porous body 23. When a voltage is applied to both ends of the porous body permeated with the liquid, a phenomenon occurs in which the liquid in the porous body moves from one electrode side to the other electrode side. This phenomenon is called electroosmotic flow, and the liquid flow generated by this phenomenon is called electroosmotic flow. In other words, the drive mechanism 20 functions as an electroosmotic flow pump by applying a voltage to the pair of electrodes (2a, 2b). Although neither is shown, a positive terminal is provided on the electrode 2a, and a negative terminal is provided on the electrode 2b, and a voltage is applied to the pair of electrodes (2a, 2b) via these terminals. Any type of power source can be connected to each terminal.

[0012] In the example of FIG. 1, a needle 8 is attached to one end of the suction-side flow path section 10 via a connecting section 5. The needle 8 is composed of an injection needle 8a and a support section 8b. In the suction-side flow path section 10, the driving liquid flows downstream through the flow path 1c due to the action of the driving mechanism section 20 (see the suction direction in the figure). In the discharge-side flow path section 30, the driving liquid flows downstream through the flow path 3c due to the action of the driving mechanism section 20. The driving liquid may be any liquid that can be used in an electroosmotic pump, such as water or alcohol.

[0013] The relief pipe 50 is a tubular member made of, for example, resin and having a flow path 5c. One end of the relief pipe 50 is connected to a portion of the drive mechanism 20 between the suction-side flow path 10 and the porous body 23. The flow path 5c of the relief pipe 50 communicates with a portion of the drive flow path 22c upstream of the porous body 23. Hereinafter, the portion of the drive flow path 22c upstream of the porous body 23 will also be referred to as the suction flow path 2c. The relief pipe 50 is used to release bubbles generated upstream of the porous body 23.

[0014] More specifically, the drive mechanism 20 has an escape hole 20h that opens from the drive flow path 22c to the outside of the main body 21 in a portion between the suction-side flow path 10 and the porous body 23. The escape pipe 50 is attached to the escape hole 20h so that the flow path 5c communicates with the suction flow path 2c. The other end of the escape pipe 50 is open, and in the example of FIG. 1, a lid 5a with an air hole 5h is attached to the other end of the escape pipe 50.

[0015] The electric syringe 100 is used with the relief tube 50 facing upward (with the relief hole 20h facing upward). In this state, bubbles in the suction flow path 2c move toward the other end of the relief tube 50 due to buoyancy and escape to the outside through the air hole 5h. The white dashed arrow in Figure 1 indicates the direction in which the bubbles escape. As bubbles become larger, they become less likely to float, so it is advisable to shake the relief tube 50 while the bubbles are still as small as possible to promote the movement of the bubbles toward the other end.

[0016] 1, the outer periphery of each flow path and components contained in the main body 21 are indicated by dashed lines. However, only the outlines of the lid 5a, the connecting portion 5, and the needle 8 are shown. Each component of the electric syringe 100 may be made of a transparent material, a translucent material, or an opaque material.

[0017] As described above, the electric syringe 100 of the first embodiment includes the suction-side flow path 10 having the flow path 1c in which the drive liquid is stored, and the drive mechanism 20 having the drive flow path 22c, which includes a pair of electrodes (2a, 2b) and the porous body 23 sandwiched between them and communicates with the flow path 1c. The electric syringe 100 also includes the tubular relief pipe 50, one end of which is connected to a portion of the drive mechanism 20 between the suction-side flow path 10 and the porous body 23, and the flow path 5c of the relief pipe 50 communicates with the suction flow path 2c. Therefore, bubbles generated upstream of the porous body 23 are guided to the flow path 5c of the relief pipe 50, thereby preventing bubbles from accumulating in the suction flow path 2c. In other words, bubbles are generated when the pressure in the suction-side flow path 10 decreases due to the action of the drive mechanism 20. When the diameter of the bubbles reaches approximately the inner diameter of the suction-side flow path 10, the drive mechanism 20 becomes inoperable, and the flow of the drive liquid stops. In this regard, in the electric syringe 100, bubbles generated upstream of the porous body 23 are guided to the relief tube 50, and therefore the operation of the electroosmotic pump is not hindered. Therefore, the electroosmotic pump can be stably operated, and the suction or discharge of liquid or gas can be performed smoothly and without interruption.

[0018] Embodiment 2 An example of the configuration of the electric injector 200 according to the second embodiment will be described with reference to Fig. 2. The same components as those of the electric injector 100 according to the first embodiment described above will be designated by the same reference numerals or symbols, and their description will be omitted or simplified. In Fig. 2, dashed lines indicating the outer peripheries of the flow paths and the components contained in the main body 21 will be omitted.

[0019] 2, the electric injector 200 has a suction-side flow path section 10, a drive mechanism section 20, a discharge-side flow path section 30, a relief pipe section 150, a swing mechanism section 60, and a check valve 80. The suction-side flow path section 10 of the second embodiment is composed of a first flow path section 11 on the upstream side and a second flow path section 12 on the downstream side.

[0020] The relief pipe 150 is a tubular member made of, for example, resin and having a flow path 5c. FIG. 2 illustrates a relief pipe 150 that is U-shaped in side view. The relief pipe 150 is used to release bubbles generated upstream of the porous body 23. One end of the relief pipe 150 is attached to the relief hole 20h of the drive mechanism 20, and the other end is connected to the boundary between the first flow path 11 and the second flow path 12. In the example of FIG. 2, a T-shaped flow path branch member 55 connects the suction-side flow path 10 and the relief pipe 150, connecting the flow path 1c and the flow path 5c. Therefore, a flow of driving liquid is generated in the flow path 5c of the relief pipe 150 in the direction of the loop-shaped arrow in FIG. 2.

[0021] More specifically, the relief pipe 150 illustrated in FIG. 2 is configured with a first pipe 51 extending linearly from one end, a second pipe 52 connected to the first pipe 51 and extending substantially perpendicular to the first pipe 51, and a third pipe 53 connected to the second pipe 52 and extending substantially perpendicular to the second pipe 52. The relief pipe 150 is provided with an air vent 5h, which serves as an outlet for air (bubbles), on the outside of the connection between the first pipe 51 and the second pipe 52. The air vent 5h is also used to inject water into the relief pipe 150 during the preparation stage of the electric injector 100. Although not explicitly shown in FIG. 2, the size of the air vent 5h may be adjusted taking into consideration the ease of bubbles escaping, the ease of water injection, and the like.

[0022] The swing mechanism 60 includes a contact member 61 that is arranged to be able to contact the relief pipe 150 near the connection point with the drive mechanism 20, and a drive means 62 that operates the contact member 61. The contact member 61 is arranged to be able to contact the relief pipe 150. The drive means 62 includes, for example, an electromagnet that generates magnetic force when an electric current is passed through it, and a magnet, and is configured so that the contact member 61, which is linked to the magnet, operates by switching the state of electricity to the electromagnet (on / off switching). FIG. 2 illustrates a rod-shaped contact member 61. The swing mechanism 60 is configured so that the contact member 61 pushes against or moves away from the first pipe 51 by applying electricity to the drive means 62, and this operation promotes the movement of bubbles in the suction channel 2c to the relief pipe 150.

[0023] The check valve 80 is provided in the second flow path section 12 and restricts the liquid to flow only from the first flow path section 11 side to the drive mechanism section 20 side (only from the boundary between the first flow path section 11 and the second flow path section 12 to the drive mechanism section 20 side). In other words, the check valve 80 is attached to the second flow path section 12 so as to prevent liquid from flowing directly from the drive mechanism section 20 toward the suction-side flow path section 10 (without passing through the relief pipe section 150). The check valve 80 also serves to prevent liquid from flowing from flow path 1c of the suction-side flow path section 10 into flow path 5c of the relief pipe section 150. The check valve 80 also serves to guide bubbles in the suction flow path 2c to the relief pipe section 150.

[0024] As described above, electric syringe 200 of the second embodiment has tubular relief pipe 150, one end of which is connected to a portion of drive mechanism 20 between suction-side flow path 10 and porous body 23, and flow path 5c of relief pipe 150 communicates with suction flow path 2c. Therefore, bubbles generated upstream of porous body 23 are guided to relief pipe 50, which allows stable operation of the electroosmotic pump and smooth, uninterrupted suction or discharge of liquid or gas.

[0025] The other end of the relief tube 150 is connected to the suction-side flow path 10. Therefore, the flow in the suction direction created by the drive mechanism 20 also acts on the relief tube 150, making it possible to create a flow of bubbles from one end to the other end. In the case of the electric syringe 100 of the first embodiment, if the bubbles do not flow smoothly to the air vent 5h, it is necessary to stimulate the relief tube 50 artificially, for example by shaking the relief tube 50. In this regard, the electric syringe 200 has a swinging mechanism 60 that includes a contact member 61 that is arranged to be able to abut against the relief tube 150 and a drive means 62 that operates the contact member 61. Therefore, it is possible to create a flow of bubbles toward the air vent 5h without requiring any manual intervention. In addition, the suction-side flow path section 10 may be provided with a check valve 80 between the connection point with the relief tube section 150 and the connection point with the drive mechanism section 20, for restricting the flow of liquid in the direction toward the drive mechanism section 20. Other effects that can be achieved by the electric injector 200 are similar to those of the electric injector 100 of the first embodiment.

[0026] The above-described embodiments are merely examples of the electric syringe according to the present invention, and the technical scope of the present invention is not limited to these embodiments. For example, while Figs. 1 and 2 illustrate the electric syringes 100 and 200 used for sucking waste materials, body fluids, blood, etc. from the human body, the electric syringes 100 and 200 may also be used for discharging (administering) a medicinal solution or the like from the discharge-side flow path section 30. In this case, it is preferable to store the medicinal solution or the like in the discharge-side flow path section 30, and attach the needle section 8 to the downstream end of the discharge-side flow path section 30.

[0027] The swing mechanism 60 is not limited to the example shown in FIG. 2 , and various other mechanisms may be employed. For example, the swing mechanism 60 may be configured with a drive unit 62 including a motor and a contact member 61 that protrudes axially from a disk-shaped member attached perpendicular to the motor's rotation shaft. In this case, the contact member 61 is attached near the outer periphery of the disk-shaped member and configured to move toward or away from the first pipe 51 in response to the rotation of the motor. As described above, bubbles become less likely to float as they grow larger. Therefore, to break down (reducing) bubbles and promote their movement, a vibration imparting unit that imparts ultrasonic vibrations to the bubbles near the suction flow path 2c in the drive mechanism 20 may be provided. The vibration imparting unit may indirectly impart ultrasonic vibrations to the bubbles via the relief pipe 50, 150. However, the vibration imparting unit may be attached both to the drive mechanism 20 near the suction flow path 2c and to the relief pipe 50, 150.

[0028] The relief pipe portion 150 is not limited to being U-shaped in side view, and various other shapes may be employed. For example, the relief pipe portion 150 may be formed in a V-shape in side view. In this case, the relief pipe portion 150 may be formed so that the portion extending from the connection point with the drive mechanism portion 20 is approximately perpendicular to the suction-side flow path portion 10. The relief pipe portion 150 may be provided with an air vent 5h at the bent portion of the V-shape in side view. The relief pipe portion 150 may be provided with a cover portion 5a with an air vent 5h at the bent portion of the V-shape in side view. [Explanation of symbols]

[0029] 1c, 3c, 5c flow path, 2a, 2b electrode, 2c suction flow path, 5 connecting portion, 5a lid portion, 5h vent hole, 8 needle portion, 8a injection needle, 8b support portion, 10 suction side flow path portion, 11 first flow path portion, 12 second flow path portion, 20 drive mechanism portion, 20h relief hole, 21 main body portion, 22 drive portion, 22c drive flow path, 23 porous body, 30 discharge side flow path portion, 50 relief pipe portion, 51 first pipe portion, 52 second pipe portion, 53 third pipe portion, 55 flow path branching member, 60 swing mechanism portion, 61 abutment member, 62 drive means, 80 check valve, 100, 200 electric syringe, 150 relief pipe portion.

Claims

1. a suction-side flow path portion having a flow path in which the driving liquid is stored; a driving mechanism including a pair of electrodes and a porous body sandwiched between the pair of electrodes, the driving mechanism having a driving flow path communicating with the flow path; a tubular relief pipe portion having one end connected to a portion of the drive mechanism portion between the suction-side flow path portion and the porous body.

2. The relief pipe portion is The electric syringe according to claim 1, wherein the other end is connected to the suction-side channel portion.

3. The suction-side flow path portion The electric syringe according to claim 2, wherein a check valve is provided between a connection point with the relief tube and a connection point with the drive mechanism, the check valve restricting the flow of liquid in a direction toward the drive mechanism.

4. The electric syringe according to any one of claims 1 to 3, further comprising a swing mechanism including: an abutment member arranged to be able to abut against a portion of the escape tube near a connection point with the drive mechanism; and drive means for operating the abutment member.

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