JP2001245975A - Transfusion pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery-driven portable transfusion pump operable continuously for a long time. SOLUTION: When a high efficiency variable voltage circuit 21, which cannot adjust voltage precisely but can vary an output voltage with good energy conversion efficiency, and a high precision variable voltage circuit 22 regulating a voltage with a predetermined precision are combined together, an output voltage of a battery is fed to the high precision variable voltage circuit 22 after it is lowered to a voltage value slightly higher than a voltage value necessary for driving a direct current motor by means of the high efficiency variable voltage circuit 21, and an energy loss in the high precision variable voltage circuit 22 can be minimized. In addition, when a direct current motor rotation detector 17 and an injection state monitoring sensor 24 are intermittently operated, power consumption is lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infusion pump, and more particularly to a portable infusion pump for administering a drug such as a high-calorie infusion to a living body.

[0002]

2. Description of the Related Art Conventionally, it can be worn on a patient's body,
A battery-powered portable infusion pump has been proposed. Since these portable infusion pumps are required to be small and lightweight, batteries having a relatively small energy amount are employed.

According to these infusion pumps, a motor is used as an actuator for transporting a medicine.
In a portable infusion pump, a DC motor is employed in terms of energy conversion efficiency.

In a portable infusion pump employing a DC motor, the liquid injection speed is controlled by adjusting the rotation speed of the DC motor based on a desired injection speed. The rotation speed of the DC motor is controlled by adjusting the voltage value of a DC power supply that drives the DC motor. The rotation speed of the DC motor is proportional to the voltage value. The voltage value is increased to increase the rotation speed, and the voltage value is decreased to decrease the rotation speed.

[0005] Since the accuracy of the DC motor rotation speed depends on the accuracy of the voltage adjustment of the drive power supply, a precision voltage variable means capable of precisely adjusting the voltage value is employed. As the precision voltage varying means, a dropper type electronic circuit that adjusts the voltage by consuming power unnecessary for driving the DC motor by a transistor or the like is often adopted because of its simple configuration.
FIG. 5 shows a dropper type electronic circuit 100 as an example. The operational voltage of the DC motor 102 is adjusted by the operational amplifier 101 included in the dropper-type electronic circuit 100 so as to match the set voltage. The power source for driving the DC motor is a battery
Energy supplied from 104 and unnecessary for driving the DC motor is consumed by the transistor 103. An electronic governor type voltage adjusting means generally adopted as a DC motor control type is also a dropper type.

[0006] The desired infusion rate (ml / h) depends on the condition of the patient and the drug to be administered. The DC power source for driving the DC motor needs to have a voltage high enough to realize the maximum infusion rate of the portable infusion pump, and is usually supplied directly from a battery as shown in FIG.

There is also a portable infusion pump provided with a means for monitoring the rotation of the DC motor by mechanically attaching an optical or magnetic rotation detector to the DC motor. In such a portable infusion pump, the actual rotation speed of the DC motor is compared with a desired rotation speed for the purpose of correcting the rotation speed of the DC motor and improving infusion accuracy.

Further, in order to ensure safety, there is also a portable infusion pump provided with sensing means for monitoring the closing of the flow path, the injection state of a chemical such as empty liquid in the flow path, and the like.

[0009]

However, when a dropper method is used as a method for adjusting the DC motor drive voltage, energy loss occurs in the electronic circuit. The energy loss when the DC motor driving power is supplied from the battery shown in the example of FIG. 5 is “((battery voltage value) − (voltage value required for DC motor driving)) × (flows to DC motor). Current value) ". Since this value is a considerably large value, it is difficult to continuously operate the portable infusion pump for a long time.

Further, when a monitoring means for monitoring the rotation of the DC motor is provided to improve the flow rate accuracy, energy is consumed in this monitoring means, so that the continuous operation time is further shortened. Would.

[0011] The continuous operation time is shortened.
The same applies to a case where a monitoring means for monitoring the state of injection of a chemical solution or the like is provided.

[0012] Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and in a portable infusion pump operated by a battery, energy loss in a motor driving means, a motor rotation detecting means, and a sensing means. It is an object of the present invention to provide an infusion pump capable of continuously operating for a long time by reducing the number of infusion pumps.

[0013]

According to the present invention, there is provided a pump for transporting a fluid having a DC motor and a variable output voltage with high energy conversion efficiency. DC motor driving first voltage variable means, DC motor driving second voltage variable means capable of performing voltage adjustment with predetermined accuracy, the first voltage variable means, and the second voltage variable means. An infusion rate control means for generating a control signal for the means, and a battery connected to the input of the first voltage variable means, the output of which is connected to the second voltage variable means, and the infusion rate control means The first voltage variable means is controlled by the control signal from the controller, and adjusts the voltage value from the battery output voltage value to a predetermined voltage value slightly higher than the voltage value required for driving the DC motor. The second voltage variable means controls the voltage adjusted by the variable means by a control signal from the infusion infusion rate control means, and adjusts the voltage value to a voltage that determines the rotation speed of the DC motor. An infusion pump characterized in that the driving power is saved (low power consumption).

Further, rotation monitoring means for monitoring the rotation of the DC motor, rotation monitoring control means for intermittently operating the rotation monitoring means, and measuring the rotation speed of the DC motor based on an output signal of the rotation monitoring means. And a rotation speed control means for performing feedback control to the pump means in comparison with a desired rotation speed, thereby reducing the power consumption (reducing power consumption) of the DC motor drive and, at the same time, controlling the rotation monitor control means. Operating the rotation monitoring means intermittently,
An infusion pump characterized by controlling a desired DC motor rotation speed with a predetermined accuracy while maintaining low power consumption (power saving) by controlling the pump means by a rotation speed control unit.

Further, sensing means, sensor control means,
An infusion pump characterized by further comprising an infusion state determining means, controlling the rotation speed to a predetermined accuracy, and monitoring the infusion state of the chemical solution with low power consumption (power saving).

Further, there are further provided sensing means for monitoring the state of injection of the chemical solution, sensor control means for intermittently operating the sensing means, and injection state determination means for determining the state of injection of the chemical solution based on an output signal of the sensing means. An infusion characterized by providing power saving (low power consumption) of the DC motor drive and simultaneously lowering power consumption (power saving) by intermittently operating the sensing means by the sensor control means. It is a pump.

Furthermore, the apparatus further comprises a rotation monitoring means and a means for performing the rotation monitoring control means and the rotation speed control means, wherein the rotation speed is controlled with a predetermined accuracy and the injection state of the chemical solution is performed with low power consumption. Infusion pump.

Further, a pump means having a DC motor for transporting a fluid, a sensing means for monitoring a state of injection of a chemical solution, a sensor control means for intermittently operating the sensing means, and an output signal of the sensing means Injection state determination means for judging the injection state of the drug solution and monitoring the injection state of the drug solution while maintaining low power consumption (power saving) by intermittently operating the sensing means by the sensor control means. Infusion pump.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. First, FIG. 1 is an external perspective view showing a portable infusion pump 1 shown together with a state of being attached to a patient P. In this figure,
A portable infusion pump 1 is provided in the middle of a flexible tube 2 for transporting a medicine from a medicine supply source L to a living body.

FIG. 2 is a block diagram showing an embodiment of the portable infusion pump 1. Although the portable infusion pump of this embodiment is of a roller type, it may be a finger type peristaltic pump.

The flexible tube 2 is mounted so as to be sandwiched between the rotor 10 and the stator 11. When the rotor 10 rotates in the direction of arrow A, the position for pressing the flexible tube 2 advances, whereby the chemical solution is transported in the direction of arrow B.

In this embodiment, the rotary shaft 12 of the rotor 10 is mechanically connected to an output shaft 13 of a gear head 14 as conceptually indicated by a dotted line. Therefore, the DC motor 15 is supplied with electric power by the motor drive circuit 16 and rotates in the direction of arrow C. The transport speed (ml / h) of the drug to be transported, that is, the flow rate, is controlled by an MPU (Micro Processing Unit) as a central control means.
nit) 17 to set the rotation speed of the DC motor 15 to a desired value as appropriate.

The MPU 17 generates a reference voltage Vref signal as a reference for the motor rotation speed, generates a high-efficiency voltage variable circuit (first voltage variable means) 21, generates a control logic signal, and outputs a motor rotation detector (rotation monitoring means). ) Counts the output pulses of 18, and generates a power control signal for the motor rotation detector 18 and the sensor 24, and the like. The reference voltage Vref signal is a high-precision voltage variable circuit
(Second voltage variable means) 22. Reference voltage Vref
Is generated by, for example, a D / A converter circuit.
The high-efficiency voltage variable circuit 21 control logic signal is input to the high-efficiency voltage variable circuit 21 and used to set the output voltage of the high-efficiency voltage variable circuit 21.

Further, output of a control signal for displaying information of the portable infusion pump 1 such as a flow rate value set on the display 25, a problem in operation of the portable infusion pump 1, etc. Control signal output when outputting an alarm from the alarm output device 26, an injection speed setting device (injection speed setting means) 27
, And a start instruction or a stop instruction from the start / stop switch 28 is read. The infusion rate setting device 27 is operated by a medical worker so as to obtain an optimal infusion rate (ml / h) for the patient in consideration of the condition of the patient and the medicine to be administered. The start / stop switch 28
It is operated by the patient or medical staff when starting or ending the injection of the medicine.

The motor drive circuit 16 is a high-efficiency voltage variable circuit
21 and a high-precision voltage variable circuit 22. FIG. 3 shows an embodiment of the electronic circuit.

The high-efficiency voltage variable circuit 21 converts the voltage of the battery 23 to a predetermined voltage value slightly higher than a voltage value required for driving the DC motor 15 at a desired rotation speed. The voltage value is more preferably 0.2 V to 1.0 V higher than the voltage value required for driving at a desired rotation speed, and 0.2 V to 0.6 V higher to reduce energy loss. Thus, the high-efficiency voltage variable circuit 21 can save power (low power consumption) for starting the DC motor.

In the embodiment shown in FIG. 3, the switching step-down DC-DC converter LSI (IC1) is used. Since the IC1 operates so that the voltage of the pin 4 becomes a constant voltage, the voltage at the point D can be varied by turning on or off each of S1, S2, and S3.

As the high-precision voltage variable circuit 22, a normal drive circuit can be employed. In the embodiment shown in FIG. 3, a constant voltage circuit using an operational amplifier is used. An electronic governor circuit can be employed.

The motor rotation detector (rotation monitoring means) 18
The rotation speed of the rotating shaft 19 of the DC motor 15 is detected (measured), and the motor rotation detector DC motor 15 generates a number of output pulse signals proportional to the rotation speed. The output pulse signal is MPU17
It is used to count the number of pulses input within a certain period of time and measure the rotation speed of the DC motor 15. The measured rotation speed is compared with a desired rotation speed in the MPU 17, and Vref input to the high-precision voltage variable circuit 22 is changed according to the difference. FIG. 4 shows the motor drive circuit 16,
An embodiment of the rotation speed feedback control of the DC motor 15 by the motor rotation detector 18 and the MPU 17 is shown in a flowchart. In the embodiment, the time required for the rotor to make one rotation (second)
However, the control may be performed based on a time such as two rotations (predetermined plural rotations) or more, or 1/2 rotation.

By monitoring the output level of the motor rotation detector 18 at a frequency that is at least twice the maximum rotation speed of the DC motor 15, the rotation speed of the DC motor 15 can be measured. Therefore, power can be saved (low power consumption) by controlling the power of the motor rotation detector 18 by the MPU 17 and intermittently turning on the power of the motor rotation detector 18.

Incidentally, a method of measuring a time interval by applying an interrupt at the rising or falling of the output pulse may be adopted.

The output of the sensor 24 shown in FIG.
Is input to As the sensor (sensing means) 24, for example, a blockage sensor that monitors a blocked state of the flow path, a bubble sensor that detects bubbles mixed in the flow path, an empty liquid sensor that detects that the infusion of the medicine has been completed, and the like. Adopted. If the output of the sensor 24 is an analog signal, the A
Connected to / D converter input.

When it is determined from the output of the sensor 24 that the injection condition of the medicine is abnormal, the abnormal state is displayed on the display 25, and an alarm is output from the alarm output device 27. Similarly to the motor rotation detector 18, power can be saved by turning on the power of the sensor 24 only at the timing of measuring or determining the output level of the sensor 24.

[0034]

As described above, according to the present invention,
In a portable infusion pump in which infusion is performed using a DC motor, by using this method as a DC motor drive circuit, energy loss in the DC motor drive circuit can be reduced, and a longer continuous A portable infusion pump capable of infusion can be provided.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing the entire configuration of a portable infusion pump 1 shown together with a state of being attached to a patient P.

FIG. 2 is a block diagram showing a configuration of a portable infusion pump.

FIG. 3 is an electronic circuit diagram of a motor drive circuit.

FIG. 4 is a flowchart of a feedback control of the DC motor.

FIG. 5 is a DC motor drive electronic circuit according to the prior art.

[Explanation of symbols]

1 ... Portable infusion pump, 2 ... Flexible tube, 10 ... Rotor, 11 ...
Stator, 12 ... Rotor rotation shaft, 13 ... Gear head output shaft,
14 ... Gear head, 15 ... DC motor, 16 ... Motor drive circuit, 17 ... MPU (Micro Processing Unit), 18 ... Motor rotation detector, 19 ... DC motor output shaft, 20 ... Rotation shaft of motor rotation detector, 21 ... High efficiency voltage variable circuit, 22 high precision voltage variable circuit, 23 battery, 24 sensor, 25 display, 26 alarm output device, 27 flow rate setting device, 28 start /
Stop switch

Claims (6)

[Claims] 1. A pump means having a DC motor for transporting a fluid, a DC motor driving first voltage variable means capable of varying an output voltage with high energy conversion efficiency, and a voltage adjustment with a predetermined accuracy. DC motor driving second voltage variable means, infusion infusion speed control means for generating control signals for the first voltage variable means and the second voltage variable means, and an input to the first voltage variable means. A battery is connected, the output of which is connected to the second voltage variable means, the first voltage variable means is controlled by a control signal from the infusion rate control means, and the voltage value is calculated from the battery output voltage value. The voltage is adjusted to a predetermined voltage value slightly higher than the voltage value required for driving the DC motor, and the voltage adjusted by the first voltage variable means is transmitted to the control signal from the infusion rate control means. It said second voltage-variable means is controlled, infusion pump and adjusts the voltage value to the voltage which determines the rotational speed of the DC motor by. 2. A rotation monitoring means for monitoring the rotation of the DC motor, a rotation monitoring control means for intermittently operating the rotation monitoring means, and measuring a rotation speed of the DC motor based on an output signal of the rotation monitoring means. And a rotation speed control means for performing feedback control to the pump means in comparison with a desired rotation speed so as to save the power of the DC motor drive and at the same time to intermittently control the rotation monitoring means by the rotation monitor control means. The DC motor rotation speed is controlled with predetermined accuracy while maintaining low power consumption by controlling the pump means by the rotation speed control means. Infusion pump. 3. The apparatus according to claim 1, further comprising a sensing unit, a sensor control unit, and an injection state determining unit, wherein the rotation speed is controlled to a predetermined accuracy, and the injection state of the chemical solution is monitored with low power consumption. 3. The infusion pump according to at least one of ~ 2. 4. Sensing means for monitoring the state of injection of a chemical solution, sensor control means for intermittently operating the sensing means, and injection state determination means for determining the state of injection of a chemical solution based on an output signal of the sensing means. 2. The infusion pump according to claim 1, further comprising: a power supply for driving the DC motor, and a power supply is further performed by intermittently operating the sensing means by the sensor control means. 5. The apparatus according to claim 1, further comprising rotation monitoring means and means for performing rotation monitoring control means and rotation speed control means, wherein the rotation speed is controlled with a predetermined accuracy and the injection state of the liquid medicine is performed with low power consumption. The infusion pump according to any one of claims 1 and 4. 6. A pump means having a DC motor for transporting a fluid, a sensing means for monitoring a state of injection of a chemical solution, a sensor control means for intermittently operating the sensing means, and an output signal of the sensing means. An infusion pump characterized by monitoring an injection state of a chemical solution while maintaining low power consumption by intermittently operating a sensing unit by a sensor control unit and determining an injection state of a medical solution.