JPH07206098A - Fluid feeder - Google Patents

Abstract

PURPOSE:To offer an easy-to-operate device of simple construction that can securely feed a large amount of fluid by producing pressure with a gas generated in an electrochemical cell and stored in a gas container, and by transmitting the pressure to the fluid in a fluid container through water in the gas container. CONSTITUTION:An electrochemical cell 1 comprises a solid polymer proton exchange membrane 4 used as an electroyte membrane, anode 5 with a platinum electrode joined to the top surface of the membrance 4, and cathode 6 with a platinum electrode joined to the bottom of the membrance 4. An airtight container 2 holds water. A fluid container 3 provided with a discharge opening stores fluid. The container 2 is connected to the container 3 with a passage 9 which separates the water from the fluid and through which pressure generated in the container 2 is transmitted to the container 3. Thus, a gas generated in the electrochemical cell l is stored in the container 2 and produces pressure, which is transmitted to the fluid in the containers 3 through the water in the container 2, thereby discharging the fluid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid supply device for supplying a fluid, particularly a liquid, in minute amounts and with high accuracy.

[0002]

2. Description of the Related Art In recent years, various infusion pumps have been used to inject a small amount of a liquid medicine into a human body with high accuracy.

Conventional infusion pumps are syringe pumps, peristaltic (rotor type), depending on the method.
There are four types of pumps: finger pumps and bellows pumps. Of these, all except the bellows pump use a motor such as a stepping motor, a rotary solenoid motor, or a DC motor as a drive source for pushing out the chemical liquid, and the control mechanism of the chemical liquid discharge amount is extremely complicated. Their weight and size are generally large and expensive.

Therefore, it is usually used at the bedside of a hospital and is not suitable for portable or disposable type. Also, the bellows pump is a system that uses the vaporization pressure of freon gas to push the bellows and discharges the chemical liquid by the pressure, but it is difficult to control the vaporization pressure of the freon gas, especially when a small amount of chemical liquid is applied for a long time. However, there is a problem in the precision of the injection.

On the other hand, an apparatus has been proposed (Japan Patent No. 1214001) which simultaneously performs a pump function and a gas flow rate control by utilizing an electrochemical cell which generates a gas by passing a direct current. An electrochemical infusion pump utilizing the principle has been proposed. This system pushes out a chemical solution or the like with a gas generated in proportion to the amount of electricity applied when a direct current is applied to the electrochemical cell part, and various methods have been proposed. H. J. R. In the proposal of Magget (US Pat. No. 4,522,698), hydrogen is supplied to the anode of an electrochemical cell in which a porous gas diffusion electrode is bonded to both sides of a water-containing ion exchange membrane functioning as an electrolyte, When a direct current is applied between the positive and negative electrodes, hydrogen becomes hydrogen ions at the anode, and the generated hydrogen ions reach the cathode side through the ion exchange membrane, where hydrogen is generated. is there. That is, the pressurized hydrogen generated at the cathode is used as a drive source for pushing the piston, diaphragm, bellows and the like. It is also possible to use oxygen as a reactant of this electrochemical cell instead of hydrogen, and if air is used as the oxygen source to be supplied to the cathode, the structure of the infusion pump will be quite simple.

Further, as an improved type of this electrochemical infusion pump, a method utilizing an electrolysis reaction of water has been proposed (JP-A-2-302264). This method is applied to an electrochemical cell in which a cathode is bonded to one side of an ion-exchange membrane and an anode is bonded to the other surface, or an electrochemical cell in which a cathode and an anode are bonded to each other so as to be insulated from each other. Water is included, and hydrogen or oxygen generated by electrolysis of water when a direct current is applied to both electrodes or a mixed gas of hydrogen and oxygen is used as a pressure source of an infusion pump.

[0007]

When a liquid is pushed out through a bellows or a diaphragm, hydrogen or oxygen may pass through depending on the material used for the bellows or the diaphragm and react with the chemical liquid to obtain an accurate infusion amount. Absent. On the other hand, in an electrochemical-type infusion pump, the amount of gas generated is proportional to the amount of electricity flowing according to Faraday's law, so the pressure and amount of gas generated are the amount of electricity (current It is possible to control the supply amount of the target liquid with high precision because the control can be performed extremely precisely by (x time).

However, in the conventional electrochemical type infusion pump, the electrochemical cell section and the storage section of the liquid to be supplied are directly connected by a pipe or the like. Usually, the inside of this pipe is filled with water, and the gas generated when a direct current is applied to the electrochemical cell pushes the water, transfers this force to the target liquid, and pushes out the liquid.

When the liquid supply amount per unit time and total amount is extremely small, the amount of gas generated is small,
There is no problem if gas accumulates in the electrochemical cell or pipe. However, the liquid supply amount per unit time exceeds 0.5 ml, or the total liquid supply amount is 1
In the case of a large volume that exceeds ml, it is considered that the generated gas may cover a part of the electrode portion of the electrochemical cell and the original purpose cannot be achieved.

Therefore, the present invention has been made in order to solve the above-mentioned problems of the electrochemical type infusion pump, and the purpose thereof is not limited to the supply of a chemical solution but a liquid or a gas. Supply a large volume of fluid including
Simple structure, low cost, easy operation during use, and small size
It is an object to provide a fluid supply device that can be made lightweight.

[0011]

A fluid supply device according to the present invention has an electrochemical cell part having electrodes on both sides of a solid electrolyte, a closed container containing water, a fluid storage port, and a discharge port. A fluid storage unit; and a passage that connects the container and the fluid storage unit, separates the water in the container from the fluid in the fluid storage unit, and transmits the pressure generated in the container to the fluid storage unit. The gas generating electrode of the electrochemical cell section is arranged so as to be always in contact with water, and the gas generated in the electrochemical cell section causes pressure to be stored in the container, and the pressure is generated in the container. Is transmitted to the fluid in the fluid storage unit via the water and the fluid in the fluid storage unit is discharged. In the case where the container is directly attached to the electrochemical cell part, the container and the fluid reservoir are communicated with each other by the first passage attached to the side or bottom of the container, and the container and the electrochemical cell are connected. Are connected by a second passage, the first passage connecting the container and the fluid reservoir is attached to either the side of the container, the bottom of the container or the second passage.

When the first passage is attached to the second passage, the cross-sectional area of the first passage should be smaller than that of the second passage, or the first passage should face downward. Is preferred. Furthermore, the first passage is provided with a fluid separation mechanism so that water is present in the container in advance. Then, when a direct current is applied to both electrodes of the electrochemical cell section, the gas generated from the electrode attached to the upper surface of the solid electrolyte is used as a pressure source.

The electrochemical cell part which can be used in the present invention generally uses a solid electrolyte, and when electrodes are joined to both sides of the membrane and a direct current is applied, a gas is generated in proportion to the amount of electricity applied. As for cells, various kinds of cells can be used, but more specifically, the following cells can be used. 1) Porous metal electrodes are bonded to both sides of the solid polymer cation exchange membrane, and both electrodes are in contact with water.Oxygen generated from the anode or hydrogen generated from the cathode, or a mixed gas of oxygen and hydrogen when electricity is applied. To use. 2) Porous metal electrodes are joined to both sides of the solid polymer cation exchange membrane, the anode is in contact with water, the cathode is in contact with air or oxygen, and the oxygen generated from the anode by electricity is used. 3) A porous metal electrode is bonded to one surface of the solid polymer cation exchange membrane, and this is used as an anode. Manganese dioxide is used as the cathode, and oxygen generated from the anode when electricity is applied is used. 4) A porous metal electrode is bonded to one side of the solid polymer anion exchange membrane, and this is used as an anode. Manganese dioxide, nickel oxyhydroxide, etc. are used for the cathode, and oxygen generated from the anode when electricity is applied is used. 5) Electrolyte water using an inorganic solid proton conductor such as phosphomolybdic acid, stannic acid, or antimonic acid as an electrolyte, and use hydrogen or oxygen generated at that time or a mixed gas of both.

[0014]

The operation of the fluid supply device according to the present invention will be described in the case of an oxygen transfer cell using a solid polymer cation exchange membrane as an electrolyte. In this case, the container, the container side of the first passage and the second passage are filled with water in advance. Further, the electrode attached to the lower surface of the solid polymer cation exchange membrane has a structure that is constantly exposed to air.
When a direct current is applied in such a direction that the electrode attached to the upper surface of the solid polymer cation exchange membrane becomes the anode, and the electrode attached to the lower surface becomes the cathode, water is decomposed at the anode to generate oxygen, protons and electrons. Passes through the solid polymer cation exchange membrane to reach the cathode, while the electrons pass through an external circuit to reach the cathode, where oxygen in the air reacts with protons and electrons to produce water.

In the present invention, oxygen generated from the anode is used as a pressure source, that is, the oxygen generated from the anode moves upward without staying close to the anode, and then the electrochemical cell section. Move towards the container attached to the top of the and collect at the top of the container. Therefore, since oxygen and water are constantly replaced in the portion near the anode, the solid polymer cation exchange membrane is always kept in contact with water, and at the same time, the gas generated in the first passage does not enter. Then, water corresponding to the volume of oxygen generated by energization enters the first passage, and pushes out and supplies the target fluid in the fluid storage section via the fluid separation mechanism.

When the electrochemical cell portion and the container are directly connected, the first passage is attached to the side surface or the bottom portion of the container so that the electrochemical cell portion and the container form the second passage. If so, the first passage can be attached to either the side of the container, the bottom of the container or the second passage to prevent gas from entering the first passage. Furthermore, when attaching the first passage to the second passage, by making the cross-sectional area of the first passage smaller than the cross-sectional area of the second passage, or by attaching the first passage in the downward direction, The effect of preventing gas from entering the first passage is further increased.

Although a chemical liquid is usually considered as a fluid to be supplied, the application of the fluid supply device of the present invention is not limited to the supply of a chemical liquid, and it can be used for supplying any liquid or gas. It goes without saying that you can do it.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fluid supply device according to the present invention will be described below with reference to preferred embodiments. Example 1 FIG. 1 shows a sectional structure of a fluid supply device using an oxygen transfer cell as an electrochemical cell according to the present invention. In the figure, 1 is an electrochemical cell, which is a disk shape with a diameter of 15 mm and a height of 5 mm, and 2 is a container,
It has a cylindrical shape with an inner diameter of 30 mm and a height of 30 mm, and 3 is a drug solution storage unit. The electrochemical cell 1 comprises a solid polymer proton exchange membrane 4 having a diameter of 12 mm used as a solid electrolyte membrane,
An anode 5 having a platinum electrode with a diameter of 8 mm joined to its upper surface,
It comprises a cathode 6 in which a platinum electrode of the same size is bonded to the lower surface of the exchange membrane 4. Reference numeral 7 is a lead wire, and 8 is a battery as a power source. Reference numeral 9 is a first passage that connects the container 2 and the drug solution storage unit 3 and has an outer diameter of 3 mm and an inner diameter of 2 mm, and is attached to the bottom of the container 2. 10 is water, 11 is oxygen generated from the anode, 12
Is oxygen accumulated in the upper part of the container 2. Reference numeral 13 is a hole provided so that the cathode is always in contact with air. Reference numeral 14 is a chemical liquid as a liquid to be supplied, and reference numeral 15 is a fluid separation mechanism for preventing the water 10 and the chemical liquid 14 from being mixed, and here, fluorine oil was used.

Reference numeral 16 is a chemical solution discharge port, and 17 is a stopper attached to the container. When a direct current of 5.5 mA was applied to the electrochemical cell, the chemical solution was supplied at a rate of 1 ml per hour. The current efficiency at this time was about 80%.

[Second Embodiment] FIG. 2 is a view showing a sectional structure of a fluid supply apparatus according to a second embodiment. The basic structure is the same as in Example 1, and the symbols 1 to 17 in FIG. 2 indicate the same as in FIG. 1, and the first passage 9 was attached to the side surface of the container. The relationship between the energization current and the supply rate of the chemical liquid was the same as in the case of Example 1.

[Third Embodiment] FIG. 3 is a diagram showing a sectional structure of a fluid supply apparatus according to a third embodiment. The basic structure is the same as in Example 1, and symbols 1 to 17 in FIG. 3 indicate the same as in FIG.
Are communicated with each other through the second passage 18 and the first passage 9
Was attached to the bottom of the container. The relationship between the energization current and the supply rate of the chemical liquid was the same as in the case of Example 1.

[Fourth Embodiment] FIG. 4 is a diagram showing a sectional structure of a fluid supply apparatus according to a fourth embodiment. The basic structure is the same as in Example 1, and the symbols 1 to 17 in FIG. 4 indicate the same as in FIG.
Are communicated with each other through the second passage 18 and the first passage 9
Attached to the second passage 18. The relationship between the energization current and the supply rate of the chemical liquid was the same as in the case of Example 1.

[Fifth Embodiment] FIG. 5 is a view showing a sectional structure of a fluid supply apparatus according to a fifth embodiment. The basic structure is the same as that of Example 1, and symbols 1 to 17 in FIG. 5 indicate the same as those in FIG.
Are communicated with each other through the second passage 18 and the first passage 9
Mounted in the second passage 18 in a downward direction. Further, a thin rubber bladder (bag) 19 was attached as a fluid separation mechanism for preventing the mixing of water and the chemical liquid. When the pressure of oxygen generated by the energization pushes water and the water in the first passage pushes the rubber bladder, the rubber bladder bulges toward the chemical liquid side and pushes out the chemical liquid. The relationship between the energization current and the supply rate of the chemical liquid was the same as in the case of Example 1.

Example 6 A water electrolysis cell is used as the electrochemical cell, and the structure is the same as that shown in FIG. Both the anode side and the cathode side are filled with water, and oxygen generated from the anode by energization is used as a pressurized gas, and at the same time hydrogen generated from the cathode is released to the outside from the hole 13. The relationship between the current supplied and the supply rate of the chemical solution is
It was the same as in the case of Example 1.

[0025]

In the fluid supply device according to the present invention, the pressurized gas is generated from the electrode attached to one side of the solid electrolyte membrane, and the upper part of the container having water inside is attached to the upper part of the electrochemical cell. Accumulate. At this time, gas and water are constantly replaced in the vicinity of the electrodes, and the solid electrolyte is always in contact with water, so that the solid electrolyte is in a state of being sufficiently absorbed and swollen. Further, since the solid electrolyte does not dry, the electric conductivity of the solid electrolyte is always constant, so that the internal resistance of the electrochemical cell is kept constant, and the characteristics of the electrochemical cell do not change during energization. Further, the first passage connecting the container and the fluid storage portion is attached to the side surface or the bottom portion of the container or the second passage so that the cross-sectional area of the first passage is smaller than that of the second passage. , Or by attaching the first passage to the second passage in a downward direction, when the gas generated from the electrode attached to the upper surface of the solid electrolyte membrane moves to the upper part of the container, Since it does not enter, it is possible to prevent the gas from reacting by mixing with the chemical liquid. In addition, by using the stopper attached to the container, it is possible to easily remove gas after use and replenish the consumed water. In addition, since the gas generated in response to the amount of electricity supplied to the electrochemical cell is almost exactly used for the pressurizing source, the amount of the chemical solution supplied per unit time is determined very accurately by the value of the current. be able to.

In the embodiment, the case of supplying the chemical liquid has been described, but the fluid supply device according to the present invention can be used not only for the chemical liquid but also for all kinds of liquids and gases. As for the shape of the passage and the second passage, in addition to the circular cross section described in the embodiments, any shape such as a square, a rectangle, or an ellipse can be used. Further, as the material of the fluid supply device of the present invention, various plastics, glasses, metals and the like can be used, but preferably, those which do not cause corrosion by water or fluid are preferable.

As described above, the fluid supply device according to the present invention is not only simple in structure and easy to operate in use, but also more fluid than the conventional bellows or diaphragm and the conventional electrochemical type fluid supply device. It has an advantage that a large volume of fluid can be reliably supplied. further,
There is no fear that the necessary current will not flow due to the decrease in the conductivity of the solid electrolyte, and the generated gas will not accumulate in the pipe and mix with the liquid to be supplied.
Therefore, the industrial value of this invention is extremely high.

[Brief description of drawings]

FIG. 1 is a diagram showing a cross-sectional structure of a fluid supply device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a cross-sectional structure of a fluid supply device according to a second embodiment of the present invention.

FIG. 3 is a view showing a sectional structure of a fluid supply device according to a third embodiment of the present invention.

FIG. 4 is a view showing a sectional structure of a fluid supply device according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a cross-sectional structure of a fluid supply device according to a fifth embodiment of the present invention.

[Explanation of symbols]

 1 Electrochemical Cell Section 2 Container 3 Chemical Solution Filling Section 9 First Passage 15 Fluorine Oil 18 Second Passage 19 Rubber Bladder

Claims (1)

[Claims] 1. An electrochemical cell part having electrodes attached to both sides of a solid electrolyte, a closed container containing water, a fluid storage part for storing a fluid and having a discharge port, and the container and the fluid storage part are connected. And a passage for separating the water in the container and the fluid in the fluid storage part and transmitting the pressure generated in the container to the fluid storage part, and the gas generating electrode of the electrochemical cell part is always It was placed so as to come into contact with water,
The gas generated in the electrochemical cell section is stored in a container to generate a pressure, the pressure is transmitted to the fluid in the fluid storage section through the water in the container, and the fluid in the fluid storage section is discharged. A fluid supply device characterized by the above.