JPS6363B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an infusion pump used to continuously infuse a human body or the like for a predetermined period of time.

Today, in the medical field, various types of infusion pumps are used for administration of drug solutions, extracorporeal circulation, perfusion experiments on animals for various research purposes, and the like.
However, since most of these types of pumps have a constant flow rate, the idea of making the infusion pattern closer to the hemodynamics of the living body is that the Pulsatile is used for extracorporeal circulation in cardiac surgery and perfusion of medicinal solutions in organ preservation. There is a growing demand for pumps with a variety of infusion patterns.

Conventional infusion pumps with a pulsatile infusion pattern have been of the plunger type or diaphragm type, but these types of pumps have the disadvantage that the pump mechanism limits the infusion pattern and lacks versatility. There is.

The applicant has already developed a micro-liquid delivery system consisting of a pump section in which an elastic tube is wound around a rotating body having a plurality of concentrically arranged rollers, and a pulse motor for rotationally driving the rotating body. Developed a pump and filed a patent application (Japanese Unexamined Patent Publication No. 124306/1983). However, in this type of pump, the liquid feeding amount control signal is converted into a pulse train having a frequency proportional to the signal, and the obtained pulses are converted into the pulse train necessary for driving the pulse motor, thereby controlling the drive of the pulse motor. As a result of further research and improvement, the inventors have developed a system in which the rotation speed of the pulse motor is driven in a rotation mode consisting of adjustable acceleration, first constant speed, deceleration, and second constant speed. We have found that by setting this, it is possible to configure the pump to perform a pulsatile infusion pattern with an arbitrary steady flow.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a motor-driven infusion pump equipped with a motor drive control circuit that can operate the pump in any pulsatile infusion pattern.

The main object of the present invention is to provide a pump unit, a control circuit for instructing a motor to rotate in a rotation mode consisting of adjustable acceleration, first constant speed, deceleration, and second constant speed, and The control circuit includes a motor that rotates and controls the drive of the pump section, and the control circuit includes an oscillator that sets acceleration, first constant speed, and deceleration times, and a second constant speed that sets the cycle of the rotation mode. an oscillator that determines time; a state counter that commands the operation of each oscillator and also commands an addition or subtraction operation to an addition or subtraction counter; an addition/subtraction counter that adds or subtracts a signal from the oscillator according to the commands of the state counter; A comparator that inputs an adjustable bias amount that determines a reference infusion volume as a second constant rate as an initial value for addition/subtraction and detects a match between the output value of the addition/subtraction counter and the bias amount; A frequency correction circuit supplies a signal to the addition/subtraction counter to keep the acceleration time and deceleration time unchanged based on this bias amount, and a frequency correction circuit that generates a pulse that determines the start timing of each rotation mode, and OR
a plurality of monostable multivibrators input to the state counter via gates, a frequency converter for converting the contents of the addition/subtraction counter into a pulse signal having a frequency proportional to the output pulse of the frequency converter; It consists of a motor drive circuit that applies rotational speed to the motor, and is characterized in that it is configured to perform pump operation in a pulsatile infusion pattern.

In the above-mentioned infusion pump, the pump section can be constructed by winding an elastic tube around a rotating body having a plurality of rollers.

Further, it is preferable that the motor be configured to use a pulse motor to rotationally drive the rotating body of the pump section.

Next, embodiments of the infusion pump according to the present invention will be described in detail below with reference to the accompanying drawings.

The infusion pump according to the present invention basically includes a pump section, a motor for driving the pump section, and a control circuit for rotationally driving the motor. A tube type pump in which an elastic tube is wound around a rotating body having a plurality of rollers is preferably used as the pump part, and a pulse motor is used as the motor to drive the rotating body of the pump part. It is suitable if

Next, the control circuit of the infusion pump of the present invention configured as described above will be explained. In FIG. 1, reference numerals 10, 12, and 14 each indicate an oscillator that determines the rotation mode of the pulse motor 16, that is, the infusion pattern of the infusion pump, 10 is an oscillator for accelerated rotation control, and 12 is an oscillator for first constant speed rotation control. 14 is an oscillator for controlling deceleration rotation, and these oscillators control the rotational drive of the pulse motor by dividing it into three regions: accelerated rotation, first constant speed rotation, and deceleration rotation, and adjust the time for each region. This allows the rotation mode to be set arbitrarily. Note that reference numeral 18 is an oscillator that determines the period of the infusion pattern, and 20 is an oscillator that determines the maximum amount of infusion.

First, in the initial state, the frequency dividers 22 and 24
, flip-flop 26, and status counter 28
and addition/subtraction counter 30 have all been reset. Therefore, the output of flip-flop 26 will be at a low potential and oscillators 18 and 20 will not operate.
Further, the outputs Q ₁ to _{Q 4} of the state counter 28 are all at low potential, and the oscillators 10, 12, and 14 do not operate. Further, the output D of the addition/subtraction counter 30 also becomes a low potential, so that the pulse motor 16 is not driven and no pump operation is performed.

Next, when the start signal A is applied, the monostable multivibrator 32 is activated, and this output signal is
While setting the bias value C as an initial value in the addition/subtraction counter 30 via the OR gate 64,
The output signal of OR gate 64 is further
4 as a clock to the status counter 28, and increments the contents of the status counter 28 by one.
That is, in this case, the output of the state counter 28
Only _Q1 is set to high potential. Start signal A also sets flip-flop 26, which causes the output of flip-flop 26 to go high, activating oscillators 18 and 20.

The oscillator 10 starts operating due to the output Q ₁ of the status counter 28 becoming a high potential. At this time, the signal of the oscillator 10 is input to the addition/subtraction counter 30 via the OR gate 36 and the frequency converter 58, but the frequency converter 58 and the complementer 60 constitute a frequency correction circuit, and the signal of the oscillator 10
It acts to convert the signal frequency from C according to the bias value C.

Generally, acceleration time t ₁ and deceleration time t ₃ are defined by the following equations.

t ₁ = T ₁ ×N ... (1) t ₃ = T ₃ × N ... (2) However, T ₁ ... Output signal period of the oscillator 10 for acceleration rotation control T ₃ ... Output of the oscillator 14 for deceleration rotation control Signal period N...The number of counts from 0 to the maximum of the addition/subtraction counter 30 Therefore, the addition/subtraction counter 30 has a bias value C
Since the operation is performed by adding up to the maximum value and subtracting it from the maximum value to the bias value C, the acceleration/deceleration time at this time is t ₁ ′,
t ₃ ′ is calculated using the following formula.

t ₁ ′=T ₁ ×(N-C) ……(3) t ₃ ′=T ₃ ×(N-C) ……(4) The above equations (3) and (4) are replaced by the above equation (1), By substituting each of (2), the following equation is established.

t ₁ ′=t ₁ ×(N-C)/N ……(5) t ₃ ′=t ₃ ×(N-C)/N ……(6) As a result, acceleration/deceleration time t ₁ ′, t ₃ ' is the bias value C
It will change depending on. Therefore, in the frequency correction circuit, N of the bias value C is calculated by the complementer 60.
The frequency converter 58 multiplies the output frequency of the oscillator 10 or 14 by (N-C)/N. That is, by multiplying the periods T ₁ and T ₃ by N/(N-C) and causing the addition/subtraction counter 30 to count with this corrected signal, the bias value C is determined regardless of the bias value C as shown in the following equation. The acceleration/deceleration times t ₁ and t ₃ at zero can be maintained.

t ₁ ′=T ₁ ×N/(N-C)×(N-C) =T ₁ ×N=t ₁ ……(7) t ₃ ′=T ₃ ×N/(N-C)×(N -C) = T ₃ ×N = t ₃ (8) Note that when the bias value C is 0, the frequency correction circuit outputs the output signal of the oscillator 10 as it is. On the other hand, as the output _Q1 of the state counter 28 becomes high potential, the U/D input of the addition/subtraction counter 30 also becomes high potential, and the addition/subtraction counter 30
enters the addition mode, and performs an addition operation using the bias value C as an initial value according to the signal from the oscillator 10 corrected by the correction circuit, and continues until the content reaches the maximum. The output D of the addition/subtraction counter 30 is
The signal is input to a frequency converter 38, which converts the oscillation frequency of the infusion amount setting oscillator 20 into a pulse signal having a frequency proportional to the output D. Here, the output D of the addition/subtraction counter 30 is
As it increases with time, the output frequency of frequency converter 38 also increases with time. Therefore, the pulse signal that increases in this way is transmitted to the frequency smoother 40, the pulse motor driving logic circuit 42, and the amplifier circuit 44.
The pulse motor 16 is input to a pulse motor drive circuit composed of the following, and accelerates the pulse motor 16 to rotate. The above circuit operation is the accelerated rotation mode.

When the content of the addition/subtraction counter 30 reaches the maximum, the counter 30 generates a carry signal CA to output the monostable multivibrator 4 via the AND gate 66 only if the output _Q1 of the state counter 28 is at a high potential.
6, this monostable multivibrator 46
The output signal of is input as a clock to the state counter 28 through the OR gate 34, and the contents of the state counter 28 are incremented by one. That is, in this case, only the output _Q2 of the state counter 28 is set to a high potential. As a result, the oscillator 12 is activated. The output signal of the oscillator 12 is passed through the frequency divider 22 to the monostable multivibrator 4 after a certain period of time (time t ₂ to be described later).
8 and activates it, and this output signal is
A clock is input to the state counter 28 through the OR gate 34, and the contents of the state counter 28 are further incremented by one. This fixed period of time (time described later)
During t ₂ ), the addition/subtraction counter 30 does not operate and its contents remain at the maximum value, so the pulse signal input to the pulse motor drive circuit via the frequency converter 38 does not change. 1
The rotation of 6 does not change. The above circuit operation is the first constant speed rotation mode.

The state counter 28 receives the output signal from the frequency divider 22.
The status counter 28 advances by one.
Only the output _Q3 of is at high potential. This activates the oscillator 14, and the output signal of the oscillator 14 is OR
It is input as the clock to the addition/subtraction counter 30 via the gate 36 and the frequency converter 58. In this case, since the U/D input of the addition/subtraction counter is at a low potential, the addition/subtraction counter 30 changes to subtraction mode. That is, the addition/subtraction counter 30 subtracts from its maximum state to the bias value C using a signal obtained by correcting the signal from the oscillator 14. Therefore, the pulse signal input to the pulse motor drive circuit via the frequency converter 38 is input to the addition/subtraction counter 3.
0, and as a result the pulse motor 16 slows down over time. The above circuit operation is the deceleration rotation mode.

When the output of the addition/subtraction counter 30 matches the bias value C set in the comparator 62, the comparator 62
The monostable multivibrator 56 is activated only when the EQ (equal) output of is at a high potential and the output _Q3 of the status counter 28 is at a high potential via the AND gate 68.
is activated, and the contents of the status counter 28 are further incremented by one via the OR gate 34. That is, in this case, only the output _Q4 of the state counter 28 is set to a high potential. As a result, one cycle operation of the entire circuit (one cycle time t ₀ described later) is completed, the monostable multivibrator 50 is activated, and the output signal of this monostable multivibrator 50 is transmitted to the OR gate 5.
2 to reset the frequency divider 22, state counter 28 and addition/subtraction counter 30. Therefore, the start of the next cycle's operation mode is performed by a timer consisting of the period setting oscillator 18 and the frequency divider 24.

Therefore, in the present invention, the bias value C is input to the pulse motor drive circuit until the timer counts up, and the pulse motor 16
performs a constant rotation. This is the second constant speed rotation mode.

When the timer times up after a predetermined period of time has elapsed, the output from the frequency divider 24 activates the monostable multivibrator 54, and the output signal of the monostable multivibrator 54 is output to the OR gates 64 and 34.
The contents of the status counter 28 are incremented by one via .
That is, in this case, the output Q ₁ of the state counter 28
only is set to high potential. As the output Q ₁ of the status counter 28 becomes a high potential in this manner, the circuit operation of the pulse motor 16 resumes the aforementioned accelerated rotation mode.

Note that when the stop signal B is applied at any time during the circuit operation, the frequency dividers 22 and 24, the flip-flop 26, the status counter 28, and the addition/subtraction counter 30 are all reset, and the drive of the pulse motor 16 can be stopped. can.

FIG. 2 shows pump characteristics when driven by a pulse motor in each of the rotation modes of acceleration, first constant speed, deceleration, and second constant speed described above. As is clear from Figure 2,
The accelerated rotation mode by the operation of the accelerated rotation control oscillator 10 continues for t ₁ hour and reaches the maximum infusion amount Q _nax , and then the second constant speed rotation mode by the operation of the first constant speed rotation control oscillator 12 continues for t ₁ hour. After lasting an hour,
The deceleration rotation mode caused by the operation of the deceleration rotation control oscillator 14 continues for _t3 hours. Thereafter, the second constant speed rotation mode continues based on the bias value C until the time T ₀ of one cycle set by the cycle setting oscillator 18 ends. Therefore, the period setting oscillator 18
When the operation enters the second cycle, the rotation modes of acceleration, first constant speed, deceleration, and second constant speed are repeated.

As described above, in the present invention, by providing the frequency correction circuit consisting of the frequency converter 58 and the complementer 60, the output frequency of the oscillator 10 or the oscillator 14 is corrected, and the addition/subtraction counter is operated using this corrected signal. is counted, and the above formula
As shown in (7) and (8), it is possible to maintain the acceleration/deceleration times t ₁ and t ₃ when the bias value C is 0 regardless of the bias value C, and achieve proper infusion pump control. can.

The infusion pump according to the present invention rotates the pulse motor by setting an adjustable rotation mode consisting of acceleration, first constant speed, deceleration, and second constant speed. ) Pump operation can be easily achieved with a pulsatile infusion pattern. In addition, the pulse motor
1 consisting of acceleration, first constant speed, deceleration and second constant speed
By adjusting the respective operating times t ₁ , t ₂ , t ₃ and the period T ₀ for the cyclic operation, the pump operation can be performed with a programmable pulsatile infusion pattern. In this case, adjustment of the times t ₁ , t ₂ , t ₃ and the period T ₀ is easily achieved by making only the oscillation frequency of the oscillator 18 adjustable. Further, the maximum infusion amount Q _nax reached in the accelerated rotation mode can be similarly set adjustable by the maximum infusion amount setting oscillator 20.

As is clear from the above, the infusion injection pattern in the pump of the present invention is based on the outputs Q ₁ , Q ₂ , Q ₃ , and Q ₄ of the status counter 28, and the pulse motor is operated in an accelerated state, a constant speed state, and a decelerated state. However, the characteristics shown in FIG. 2 are obtained. Further, the rotation control of the pulse motor is performed by converting the contents of the addition/subtraction counter 30 into a frequency proportional to the contents using a frequency converter 38.
The rotation of the pulse motor is controlled via a frequency smoother 40, a pulse motor drive logic circuit 42, and an amplifier 44. At this time, the rotation speed of the motor increases when the addition/subtraction counter 30 is in the addition state, decreases when it is in the subtraction state, and rotates at a constant speed when it is in the stop state. Therefore, for example, in this example, the acceleration time t ₁ , the first constant velocity time t ₂ , the deceleration time t ₃ , the time of one cycle T ₀ and the maximum infusion area
If Q _nax is specifically set, t ₁ = 12 to 500 msec,
_t2 =10msec~1sec, _t3 =12~500msec, _T0 =0.6
~2sec, Q _nax =1ml~5l/min.

The pulse motor used in the pump of the present invention is configured to rotate at a fixed angle in response to one pulse input, and its rotational speed is such that, if used under load conditions below the allowable load torque, it will not suffer from load fluctuations as seen in DC motors. It is not affected and is precisely controlled by the number of input pulses. Therefore, by using this type of pulse motor as a pump drive motor, it is possible to digitally control the pump, allowing for complex and highly accurate flow rates that were not possible with pumps using conventional DC motors, AC motors, etc. control can be achieved.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a drive control circuit diagram of an infusion pump according to the present invention, and FIG. 2 is a characteristic curve diagram of the pump operated by the drive control circuit shown in FIG. 1. 10... Acceleration rotation control oscillator, 12... First
Oscillator for constant speed rotation control, 14... Oscillator for deceleration rotation control, 16... Pulse motor, 18... Oscillator for period setting, 20... Maximum infusion amount setting oscillator, 2
2, 24... Frequency divider, 26... Flip-flop, 28... Status counter, 30... Addition/subtraction counter, 32, 46, 48, 50, 54, 56...
Monostable multivibrator, 34, 36, 52,
64...OR gate, 38...Frequency converter, 4
0... Frequency smoother, 42... Pulse motor drive logic circuit, 44... Amplifier circuit, 58... Frequency converter, 60... Complementer, 62... Comparator, 6
6, 68...AND gate.

Claims (1)

[Scope of Claims] 1. A pump unit, a control circuit that instructs a motor to rotate in a rotation mode consisting of adjustable acceleration, first constant speed, deceleration, and second constant speed, and according to the commands of the control circuit. The control circuit includes a motor that rotates and controls the drive of the pump section, and the control circuit includes an oscillator that sets acceleration, first constant speed, and deceleration times, and a second constant speed that sets the cycle of the rotation mode. an oscillator that determines time; a state counter that commands the operation of each oscillator and also commands an addition or subtraction operation to an addition or subtraction counter; an addition/subtraction counter that adds or subtracts a signal from the oscillator according to the commands of the state counter; A comparator that inputs an adjustable bias amount that determines a reference infusion volume as a second constant rate as an initial value for addition/subtraction and detects a match between the output value of the addition/subtraction counter and the bias amount; A frequency correction circuit supplies a signal to the addition/subtraction counter to keep the acceleration time and deceleration time unchanged based on this bias amount, and a frequency correction circuit that generates a pulse that determines the start timing of each rotation mode, and OR
a plurality of monostable multivibrators input to the state counter via gates, a frequency converter for converting the contents of the addition/subtraction counter into a pulse signal having a frequency proportional to the output pulse of the frequency converter; An infusion pump that performs pump operation in a pulsatile infusion pattern, characterized by comprising a motor drive circuit that applies rotational speed to the motor. 2. The infusion pump according to claim 1, wherein the pump portion is formed by winding an elastic tube around a rotating body having a plurality of rollers. 3. The infusion pump according to claim 1 or 2, wherein the motor is a pulse motor and is configured to rotationally drive a rotating body of the pump section.