JPH0727042A - Infusion pump - Google Patents

Abstract

PURPOSE:To provide an infusion pump with supply stop mechanism capable of forming the pump simple in a structure, inexpensive and easy to operate further with miniaturization and lightening weight. CONSTITUTION:An electrochemical cell part 1, liquid storage part 5 and a supply stop mechanism 4 arranged between both the parts 1, 5 are provided, and the supply stop mechanism 4, having a through hole 9 provided in a wall part of a passage 8 for connecting the electrochemical cell part 1 to the liquid storage part 5 and a mover 12 arranged in the inside of the passage, is provided with a device for closing/opening the through hole 9 and further for separating liquid in the electrochemical cell part from liquid to be infused. Liquid to be infused is extruded by gas generated in the electrochemical cell part 1, and also actuating the supply stop mechanism 4 when a prescribed amount of infusing liquid is ended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infusion pump for supplying a liquid, in particular, a liquid medicine in minute amounts and accurately.

[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 adopt a complicated control mechanism for the discharge amount of the chemical liquid. Due to its size and weight, it is generally too large, and because it is expensive, 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 to discharge the chemical solution, but it is difficult to control the vaporization pressure of the freon gas, especially when a minute amount of chemical solution is taken over a long period of time. When injecting, there is a problem in the injection accuracy.

On the other hand, in recent years, an electrochemical infusion pump has been proposed as a new system. 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. Proposal by Magget (US Patent Nos. 4,5
No. 22,698), hydrogen is supplied to the anode of an electrochemical cell in which porous gas diffusion electrodes are joined to both sides of a water-containing ion exchange membrane that functions as an electrolyte, and a direct current is applied between the positive and negative electrodes. At that time, hydrogen is converted to hydrogen ions at the anode, the generated hydrogen ions reach the cathode side through the ion exchange membrane, and hydrogen is generated there, which is an electrochemical reaction. 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. Become.

Further, as an improved version of this electrochemical infusion pump, a method of utilizing the electrolysis reaction of water (Japanese Patent Laid-Open No. HEI-2)
-302264) is such that a cathode is bonded to one surface 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 separately bonded on one surface so as to insulate each other is made to contain water. The pressure source of the infusion pump is 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.

[0007]

When a liquid is extruded through a bellows or a diaphragm, hydrogen or oxygen may pass through depending on the material used for the bellows or the diaphragm to react with the chemical liquid or an accurate infusion amount cannot be obtained. . When using the inner cylinder of the injection cylinder, due to the frictional resistance of the inner cylinder,
There is a drawback that a large pressure is required when the inner cylinder is first moved, and an accurate relationship cannot be obtained between the gas generation amount and the infusion amount.

On the other hand, in an electrochemical type infusion pump, the amount of gas generated is proportional to the amount of electricity supplied according to Faraday's law, so the pressure and amount of gas generated are the amount of electricity supplied to the electrochemical cell. Quantity (current x
It is characterized in that it can be controlled extremely precisely depending on the time) and therefore the target liquid supply amount can be accurately determined. However, in the electrochemical type infusion pump, an excellent method of stopping the supply after supplying the required amount of the target liquid has not been proposed yet. One of the most effective methods is to stop the energization of the electrochemical cell part.However, this method usually requires the use of a timer, which is a complicated and relatively large mechanism. Not suitable for small and inexpensive infusion pumps.

The present invention has been made to solve the above problems of the electrochemical type infusion pump,
Its purpose is simple structure, inexpensive, easy operation,
Another object of the present invention is to provide an infusion pump with a supply stop mechanism that can be reduced in size and weight.

[0010]

An electrochemical type infusion pump according to the present invention is characterized in that a supply stopping device is provided between an electrochemical cell section and a storage section for a liquid to be infused. The supply stopping mechanism is a through hole provided in a wall portion of a passage that connects the electrochemical cell portion and a storage portion of a liquid to be infused, and a moving body arranged inside the passage, A through-hole is provided for closing and opening the through-hole, and for separating the liquid in the electrochemical cell part from the liquid to be infused. The supply is easily stopped. The electrochemical cell portion that can be used in the present invention is generally any type of cell as long as it is a cell that generates a gas in proportion to the amount of electricity supplied when a direct current is applied. The following cells can be used as a practical method.

1) Porous metal electrodes are bonded to both sides of a 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 oxygen and hydrogen by the application of electricity. Use mixed gas.

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 oxygen generated from the anode by energization 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 a cathode, and oxygen generated from the anode by applying electricity is used.

4) A porous metal electrode is bonded to one surface of the solid polymer anion exchange membrane, and this is used as an anode. Manganese dioxide, nickel oxyhydroxide or the like is used for the cathode, and oxygen generated from the anode by electrification is used. To use.

5) Instead of using an ion exchange membrane as an electrolyte, water is electrolyzed using an acidic or alkaline electrolytic solution, and hydrogen or oxygen or a mixed gas of both generated at that time is used.

[0016]

The infusion pump using the electrochemical method according to the present invention will be described by taking as an example the case where the liquid to be infused is a chemical liquid. The infusion pump according to the present invention sequentially transfers the pressure of gas generated when a direct current is applied to the electrochemical cell section to the liquid in the electrochemical cell section, the moving body of the supply stopping mechanism, and the chemical solution, and It supplies liquid.

Next, the chemical solution supply stopping mechanism of the infusion pump according to the present invention will be described.

The chemical liquid supply stopping mechanism is installed in a passage connecting the electrochemical cell portion and the chemical liquid storage portion, and a through hole provided in the wall portion of the passage and the liquid of the electrochemical cell portion inside the passage and the chemical liquid And a movable body capable of freely moving in the passage to close and open the through hole.

In the infusion pump according to the present invention, the positional relationship between the moving body and the through-hole before the start of operation is such that the moving body closes the through-hole, is far from the drug solution storage section, and is located in the electrochemical cell section. It is in a close position. When the infusion pump starts operating and a direct current is applied to the electrochemical cell, gas is generated.When the liquid in the electrochemical cell is pushed by the pressure, the pressure is transmitted to the moving body, which is the electrochemical cell. The drug solution moves from a position close to the part toward the drug solution storage part, and at the same time, the drug solution is pushed out and supplied from a syringe or the like. If you continue to use the infusion pump, the moving body will move more and more toward the drug solution storage unit.
Finally, the moving body reaches a position where it does not block the through hole, the liquid in the electrochemical cell section leaks to the outside from the through hole, and after that, even if the gas continues to be energized, the pressure of the gas remains in the electrochemical cell section. It is used to push the liquid out of the through hole,
The moving body does not move anymore and stops at that position. Therefore, the supply of the chemical solution is stopped. The supply amount of the drug solution can be easily determined by the position of the moving body immediately before using the infusion pump.

Pure water is usually used as the liquid in the electrochemical cell section, and a chemical liquid is usually considered as the liquid to be infused, but the infusion pump of the present invention is used. It is needless to say that the present invention is not limited to the infusion of medicinal liquids and can be used for infusion of all liquids.

[0021]

EXAMPLES Next, the infusion pump of the present invention will be described using preferred examples.

FIG. 1 shows a sectional structure of an electrochemical infusion pump according to the present invention. In the figure, reference numeral 1 is an electrochemical cell part, in which a solid polymer cation exchange membrane having a diameter of 16 mm and a platinum having a diameter of 6 mm are used. It is composed of a cell portion 2 having electrodes joined thereto and a battery 3 as a power source. Reference numeral 4 is a supply stop mechanism, 5 is a drug solution storage unit, 6 is an injection needle, and 7 is a polypropylene thin tube connecting the drug solution storage unit and the injection needle.

Next, details of the supply stopping mechanism will be described.
FIG. 2 is a diagram showing a state of the supply stop mechanism before the supply of the chemical liquid is started. In FIG. 2, 8 is a passage for connecting the electrochemical cell portion and the chemical liquid storage portion, the outer diameter is 30 mm, the inner diameter is 20 mm.
It consists of a mm tube made of PTFE. It is assumed that the electrochemical cell unit is located in the X direction and the drug solution storage unit is located in the Y direction in the figure. 9 is a diameter of 2 m provided on the wall of the passage 8.
m through hole. 10 is a liquid of the electrochemical cell part, and water is used here. 11 is a liquid medicine. 1
Reference numeral 2 is a moving body that separates water, which is a liquid in the electrochemical cell part, and a chemical liquid, and has a diameter of 20 mm and a length of 40 mm.
It was made of hollow cylinders. Before starting the chemical supply, the moving body 1
The end A on the side of the electrochemical cell of 2 is placed 32 mm closer to the electrochemical cell than the end C on the side of the electrochemical cell of the through hole 9, and the end B on the side of the chemical solution of the moving body 12 is It is located 6 mm closer to the drug solution storage unit than the end D on the drug solution storage unit side. That is, the through hole 9 is completely blocked by the moving body 12.

FIG. 3 is a view showing the state of the supply stopping mechanism when a direct current of 0.2 mA is applied to the electrochemical cell section to supply the chemical liquid, and the pressure of the generated oxygen gas is electrochemical. The moving body 12 is transferred to the water 10 which is the liquid in the cell portion, moves in the direction of the arrow, pushes the chemical liquid 11, and the chemical liquid is supplied. At this time as well, since the through hole 9 is always blocked by the moving body 12, the moving body 12 moves to the side of the chemical solution storage portion by the volume of the generated gas, so that the chemical solution proportional to the amount of electricity supplied is supplied. . Then, the moving body 12 gradually moves to the drug solution storage unit side.

When the moving body 12 reaches the position shown in FIG. 4, the supply of the chemical solution is stopped. That is, the end A on the electrochemical cell side of the moving body 12 is located on the side of the chemical liquid storage part than the end C on the side of the electrochemical cell of the through hole 9, and the water 10 which is the liquid of the electrochemical cell part.
Leaks out of the passage 8 through the through hole 9.
In this state, even if a gas is generated in the electrochemical cell part, the pressure is transmitted to the water 10 which is the liquid in the electrochemical cell part, but is not transmitted to the moving body 12, and the moving body 12 moves further. The supply of the drug solution is stopped.

Therefore, the supply amount of the chemical solution is set to the moving body 12
The distance traveled from the position shown in FIG. 2 to the position shown in FIG.
Will be determined by the product of the cross-sectional areas of In this case, since the moving body 12 has moved 32 mm after energization for 24 hours, this means that 10 ml of the chemical solution was supplied in 24 hours. That is, by selecting the initial position of the moving body 12 with respect to the through hole 9 and the cross-sectional area of the passage 8,
The supply amount of the liquid to be infused can be set to an arbitrary value.

[0027]

The chemical liquid supply stopping mechanism of the infusion pump according to the present invention is installed in the passage connecting the electrochemical cell portion and the chemical liquid storage portion, and the through hole provided in the wall portion of the passage and the inside of the passage. It has a very simple structure, and it sets the supply amount of the drug solution by the simple method of locating the through hole and the moving body before using the infusion pump. . In addition, since the gas generated in response to the amount of electricity supplied to the electrochemical cell is almost exactly applied to the pressurizing source, the amount of chemical liquid supplied per unit time can be adjusted with great accuracy by the value of the current. You can decide.

In the embodiment, the case where a small amount of the chemical liquid is supplied for a long time has been described, but the infusion pump according to the present invention is not limited to the chemical liquid and can be applied to all kinds of liquids. In addition, the shape of the passage that connects the electrochemical cell portion and the chemical liquid storage portion, which is the supply stop mechanism, is not limited to the circular cross section described in the embodiment, but any shape such as a square or rectangular cross section or an elliptical cross section. Is available.

Thus, the infusion pump according to the present invention is
Infusion using conventional bellows, diaphragm or syringe, with the advantages of simple structure, easy operation during use, compactness and light weight, and portable or disposable type. The drawbacks of the pump can be eliminated, and its industrial value is extremely high.

[Brief description of drawings]

FIG. 1 is a view showing a cross-sectional structure of an electrochemical type infusion pump according to an embodiment of the present invention.

FIG. 2 shows an electrochemical infusion pump according to the present invention,
It is a figure showing the state of the supply stop mechanism before starting the supply of the chemical liquid.

FIG. 3 shows an electrochemical infusion pump according to the present invention,
It is a figure showing a state of a supply stop mechanism during supply of a chemical solution.

FIG. 4 shows an electrochemical infusion pump according to the present invention,
It is a figure showing the state of the supply stop mechanism when the supply of the chemical liquid is stopped.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrochemical cell part 4 Supply stop mechanism 5 Chemical liquid filling part 8 Passage 9 Through hole 12 Moving body

Claims (1)

[Claims] 1. An electrochemical cell section, a storage section for a liquid to be infused, and a supply stop mechanism arranged between the two, the supply stop mechanism including an electrochemical cell section and a liquid to be infused. A through hole provided in the wall of the passage communicating with the storage section;
A moving body disposed inside the passage, for closing and opening the through hole, and for separating the liquid in the electrochemical cell part and the liquid to be infused, An infusion pump characterized in that a liquid to be infused is pushed out by a gas generated by energizing the device.