JP4594824B2 - Roller type pump device - Google Patents

Description

  The present invention relates to a roller-type pump device for feeding blood or a chemical solution by squeezing and moving a liquid in a tube by a movable member such as a roller.

A roller type pump device that feeds the liquid in the tube from upstream to downstream by squeezing the flexible tube with a pressing member such as a roller driven by a motor is used in, for example, an artificial dialyzer in the medical field. This is used when a relatively large amount of liquid is quantitatively transferred, such as when circulating blood.
The present inventors measure the amount of liquid feeding by counting the output of an encoder that indicates the amount of rotation of the motor, and control the rotation of the motor so that the amount of liquid feeding becomes the target flow rate value. Has proposed a roller-type pump device that performs flow rate control of the above (Patent Document 1).
JP 2000-80989 A

In the conventional roller-type pump device described above, a flexible tube filled with liquid and a squeezing member (roller) that squeezes and moves along the tube to flow the liquid in the tube from upstream to downstream. A motor for moving the pressing member, an operation unit for setting a set flow rate, an encoder for detecting a liquid feeding amount by the rotation amount of the motor, and rotation of the motor according to the set flow rate set by the operation unit The motor is controlled to a predetermined rotational speed by a control calculation unit that performs a predetermined operation by comparing the target value of the speed and the output of the encoder that detects the rotation amount of the motor.
However, since there is no means for correcting even if the rotational speed of the motor fluctuates due to pressure fluctuations or other disturbances and the integrated flow rate fluctuates, there has been a problem that a deviation occurs in the set liquid feeding time.

  Accordingly, an object of the present invention is to provide a roller type pump device capable of terminating the liquid feeding of the liquid feeding amount set for the set liquid feeding time.

In order to achieve the above object, the roller-type pump device of the present invention includes a squeezing member that squeezes and moves a flexible tube filled with liquid to flow the liquid in the tube from upstream to downstream, and A motor for moving the squeezing member, an operation unit for setting the liquid supply amount and the liquid supply time, a flow rate detection unit for detecting the liquid supply amount by the rotation amount of the motor, and the set liquid supply amount and liquid supply time The target value setting means for calculating the target value of the rotation amount of the motor based on the reference value, and comparing the target value with the detection output of the flow rate detection unit so that the rotation amount of the motor becomes the target value. The control arithmetic unit that outputs a control signal for controlling the motor, the integrated flow theoretical value obtained from the set liquid supply amount and the liquid supply time, and the integrated flow value measured from the output of the flow detection unit are compared. To complete the liquid delivery during the liquid delivery time. Is obtained by a target value correction means for performing a process for correcting the target value.
Further, the target value correcting means is configured to execute a process of correcting the target value every predetermined time.

According to the roller type pump device of the present invention, since the target value is corrected from the remaining liquid supply time and the remaining liquid supply time every predetermined time, the liquid amount set at the set liquid supply time can be sent out. it can.
Therefore, since the liquid supply is accurately completed within the set liquid supply time, the burden on the patient can be reduced.
In addition, since the liquid feeding time is accurate, a liquid pump operator (such as a nurse) can eliminate the dead time when looking around the end of the liquid feeding, and the work load can be reduced.

FIG. 1 is a block diagram showing a configuration of an embodiment of a roller type pump device of the present invention.
In this figure, reference numeral 1 denotes a set flow rate setting unit including an operation unit such as a key. The user operates the set flow rate setting unit 1 to set data such as a liquid supply amount, a liquid supply time, and an inner diameter of a tube to be used.
2 is a target value setting means for calculating a target rotational speed of the motor for obtaining a flow rate per predetermined time of the roller pump corresponding to the liquid feed amount and the liquid feed time set by the set flow rate setting unit 1; This is the target value (the target rotational speed of the motor). A control calculation unit 6 to be described later performs control so that the rotation amount of the motor becomes the target value 3. The target value 3 is corrected by target value correcting means 4 described later after the operation of the pump is started. Details of calculation of the target value by the target value setting means 2 will be described later.
Reference numeral 4 denotes a target value correcting means for correcting the target value 3 when a difference occurs by comparing the integrated flow rate from the start of operation to the integrated flow theoretical value every predetermined time after the start of operation of the pump. . That is, the flow rate detection amount detected by the flow rate detection unit 9 described later is integrated with the integrated flow rate theoretical value in which the liquid supply integrated amount per unit time within the liquid supply time is constant, and a predetermined time (for example, 5 If the accumulated flow when the predetermined time elapses every minute) differs from the theoretical value of the accumulated flow, the delivery will be completed within the set delivery time from the remaining delivery time and the remaining delivery time. Thus, the target value 3 is corrected. Details of the target value correction processing by the target value correcting means 4 will be described later.

Reference numeral 5 denotes a comparison unit that compares the target value 3 with a flow rate (specifically, the amount of rotation of the motor) detected by a flow rate detection unit 9 described later, and outputs a deviation.
Reference numeral 6 denotes a control calculation unit that outputs a control signal for controlling the rotational speed of the motor so that the deviation becomes as small as possible based on the deviation obtained by the comparison unit 5. Specifically, the control calculation unit 6 executes a PI (P (Proportional): proportional, I (Integral): integration) calculation, and determines the rotation speed of the motor that drives the roller pump based on the PI calculation result. A control signal for controlling is output. The rotation speed of the motor (DC brushless motor) that drives the roller pump is controlled by the pulse width of the PWM (pulse width modulation) signal, and the pulse width of the PWM signal is determined from the control calculation unit 6. An output (PWM output value) MV (n) is output. In this embodiment, the PWM output value MV (n) takes a value between 0 and 1100.
A control output unit 7 generates a PWM signal having a pulse width corresponding to the PWM output value MV (n) output from the control calculation unit 6 and supplies the PWM signal to the motor of the pump unit 8. In this embodiment, a PWM signal having a carrier frequency of 14 kHz is output as a drive signal to the motor.

8 is a roller-type pump part provided with the pressing member (roller) which flows the liquid in a tube from upstream to downstream by squeezing and moving the flexible tube filled with the liquid, from the said control output part 7 A motor (DC brushless motor) driven at a rotational speed proportional to the pulse width by the output PWM signal, a gear combined with the motor shaft of the motor, and an encoder (two-phase encoder) attached to the motor shaft ), An arm attached to the gear shaft (output shaft) of the gear, and two rollers (squeezing members) provided at both ends of the arm, and within the housing along the revolution radius of the roller The liquid in the tube is fed by squeezing and rotating the roller on the arranged flexible tube.
Reference numeral 9 denotes a flow rate detection unit that detects the flow rate of the liquid feeding by counting a pulse obtained by multiplying the output pulse from the encoder attached to the motor shaft of the motor by 4 for a predetermined time (in this embodiment, 10 ms). In this embodiment, the encoder is configured to output 500 pulses per rotation of the motor shaft, and the flow rate detection unit 9 is configured so that the output pulse from the encoder is multiplied by 4 every 10 ms. Is output as data indicating the flow rate of the liquid feeding.
In this way, the liquid feed amount is detected by the rotation amount of the motor, and PI control is performed so that the detected liquid feed amount becomes a target value calculated according to the set liquid feed amount and the liquid feed time. Yes. Then, the target value is corrected every predetermined time.

Next, the case where the following setting conditions are attached will be described in detail.
<Conditions>
・ Liquid feeding time 1 hour [h]
・ Liquid delivery volume: 12 liters [L]
・ Flow rate with respect to the rotation speed of the motor gear shaft 61 [mL / 10 rotation] (gear shaft)
・ Gear ratio 1/60
・ Encoder pulse 500 [P / R] (motor shaft)
・ Sampling period 10ms
Here, the “flow rate with respect to the rotation speed of the gear shaft of the motor” is data determined by the inner diameter of the tube to be used.

When the above conditions are set, the target value setting means 2 obtains the target value 3 described above from the following calculation formula.
First, since the flow rate detector 9 is configured to count encoder pulses by four times, the rotational speed signal is 500 × 4 = 2,000 [P / R] (2,000 per rotation of the motor shaft). Pulse) and 2,000 x gear ratio = 2,000 x 60 = 120,000 [P / R] (120,000 pulses per revolution of the gear shaft).
Further, at 1 [rpm] of the gear shaft (when the gear shaft makes one rotation per minute), 1020,000 sampling results in 120,000 / 6,000 = 20 [pulses]. That is, 20 pulses are counted in a sampling period of 10 ms.
Therefore, the number of revolutions per minute [rpm] = 4 times the number of encoder pulses (10 ms sampling) / 20. That is, the value obtained by dividing the number of pulses counted in the sampling period of 10 ms by 20 is the number of revolutions per minute of the gear shaft.

On the other hand, since the flow rate data is 61 [ml / 10 rotation], the flow rate per rotation of the gear shaft in the tube used here is 6.1 [mL]. Accordingly, the flow rate [mL / min] per minute is obtained by the following equation.
Flow rate [mL / min] = Number of revolutions x Flow rate data per revolution = (Number of encoder pulses multiplied by 4 (10 ms sampling) / 20) x 6.1
Moreover, the flow rate [L / h] per hour is expressed by the following equation.
Flow rate [L / h] = Flow rate [mL / min] x 60 / 1,000
= (Number of encoder pulses multiplied by 4 (10ms sampling) / 20) x 6.1 x 60 / 1,000
Therefore, the target value (number of pulses in a sampling period of 10 ms) when the set flow rate is 12 [L / h] is
Target value by target value setting means 2 (10ms sampling)
= Flow rate [L / h] x 20 x 1,000 / (6.1 x 60) (1)
= 12.00 × 20 × 1,000 / (6.1 × 60)
= 655.7
It is obtained.

In this way, in the case of the setting condition described above, the target value 3 is set to “655.7”.
As described above, the control calculation unit 6 performs the PI calculation based on the deviation obtained by comparing the target value 3 (“655.7”) with the output of the flow rate detection unit 9 by the comparison unit 5. Thus, the PWM output value MV (n) is obtained and the result is output to the control output unit 7. The motor (DC brushless motor) of the pump unit 8 is PWM-driven by the control output unit 7 (in this embodiment, the carrier frequency: 14 kHz, the clock count within one cycle of the PWM output: 1,100). PI control is performed so that the output becomes the target value 3 (“655.7”).
That is, feedback control is performed so that the number of pulses of the two-phase encoder provided in the motor of the pump unit 8 is 655.7 / 4.

Next, the target value correction process executed in the target value correction means 4 will be described. Although the time interval for executing the target value correction process can be arbitrarily set, here, it is assumed that the target value correction process is executed every 5 minutes.
Under the above-mentioned setting conditions, the integrated flow rate theoretical value when 5 minutes have elapsed from the start of operation (the integrated flow rate value when the liquid feed is performed according to the target value 3) is 12 × 5/60 = 1 [L].
On the other hand, if the average of the output of the flow rate detection unit 9 is “642.6” with respect to the target value “655.7” and the error is about −2%, the actual integrated flow rate value is
Actual integrated flow rate = 12 [L] x (5/60) x 0.98 (= 642.6 / 655.7) = 0.98 [L] (2)
It becomes. Therefore, the remaining liquid supply amount for the remaining 55 minutes is
55 minutes remaining liquid = 12-0.98 = 11.02 [L] (3)
And to complete the liquid delivery in one hour,
Flow rate for the remaining 55 minutes = (11.02 [L] / 55) x 60 = 12.022 [L / h] (4)
It is necessary to change the target value 3 so that
Therefore, from equation (1)
Target value (10 ms sampling) = Flow rate [L / h] x 20 x 1000 / (6.1 x 60) = 12.022 x 20 x 1000 / (6.1 x 60) = 656.9
Thus, the target value 3 is corrected to a new target value (flow rate correction) of “656.9”.
Furthermore, by performing the target value correction process similarly every 5 minutes, liquid feeding can be completed within the liquid feeding scheduled time.
In the above-described embodiment, the target value correcting unit is described as being executed every 5 minutes. However, this time may be a short time, for example, every 1 minute or every 10 seconds. Also good. Of course, the shorter the time, the smaller the correction amount.

FIG. 2 is a diagram illustrating the error between the integrated flow rate theoretical value and the actual integrated flow rate and its correction. In this figure, the horizontal axis represents time, and the vertical axis represents the amount of liquid delivered.
a is an accumulated flow theoretical value, and shows the case where the pump unit 8 is controlled without error between the target value 3 set by the target value setting means 2 and the flow rate detected by the flow rate detection unit 9. ing. The integrated flow rate theoretical value a is represented by a straight line having a liquid feed amount of 12 [L] in a liquid feed time of 60 minutes.
b indicates the integrated flow rate measured from the detection output of the flow rate detection unit 9. This figure shows that the accumulated flow theoretical value a after 5 minutes from the start of operation is 1 [L], but the accumulated flow b, which is the amount of liquid actually fed, has an error of about − The case where 2% is generated and becomes 0.98 [L] is shown.
c, the target value is corrected by the target value correction means 4 so that the liquid supply can be completed in the remaining 55 minutes when the accumulated flow rate error for 5 minutes after the start of operation is −2%. It is a straight line showing the corrected integrated flow rate when corrected.
That is, as described above, the remaining liquid supply amount for 55 minutes is 12−0.98 = 11.02 [L], and the flow rate for the remaining 55 minutes is 55 minutes to complete the liquid supply in one hour. Flow rate = (11.02 / 55) × 60 = 12.022 [L / h]. Therefore, from the equation (1),
Target value (10ms sampling) = Flow rate [L / h] x 20 x 1000 / (6.1 x 60) = 12.022 x 20 x 1000 / (6.1 x 60) = 656.9
Thus, by correcting the target value 3 to the new target value (flow rate correction) “656.9”, as shown in c, the liquid feeding can be completed in the remaining 55 minutes.

  In addition, about the integer of a target value, and the process below a decimal point, you may process using the means which the present inventors processed by the patent 3423633 (Unexamined-Japanese-Patent No. 2000-80989). That is, a period during which control is performed using the target value 3 as the integer part of the target value calculated by the target value setting means 2 and a period during which control is performed using the target value 3 as the integer part of the calculated target value + 1. Control may be performed by setting the period according to the value of the decimal part of the value.

FIG. 3 is a diagram showing a processing flow of target value correction in the roller pump device of the present invention.
When the process is started, it is first determined whether the pump unit 8 is in an operating state or in a stopped state (step S1). When the pump unit is stopped, the process is terminated.
When the pump unit 8 is in an operating state, a target value is set by the target value setting means 2 (step S2). For example, as mentioned above, the conditions are as follows: ・ Liquid feeding time 1 [h]
・ Liquid feed amount 12 [L]
・ Flow data for motor shaft speed 61 [mL / 10 rotation] (gear shaft)
・ Gear ratio 1/60
・ Encoder pulse 500 [P / R] (motor shaft)
・ Sampling period 10ms
As described above, the target value “655.7” is set as described above.

Next, the timer for setting the period for correcting the target value (in this embodiment, the target value is corrected every 5 minutes, so the timer for counting 5 minutes) is reset, The operation is started (step S3).
Then, it is determined whether or not the liquid feeding is finished (step S4). This determination is made by comparing the liquid supply amount set by the set flow rate setting unit 1 with the integrated flow rate calculated from the flow rate detected by the flow rate detection unit 9, and when they match, the liquid supply amount Is finished, the operation of the pump unit 8 is stopped (step S8).
When the liquid feeding is not completed, the process proceeds to step S5, and it is determined whether or not 5 minutes have elapsed since the target value correction by the target value correcting means 4 was performed. This is determined by whether or not the count value of the timer has reached 5 minutes. If five minutes have not elapsed, the process returns to step S4 and waits for five minutes to elapse.
When 5 minutes have elapsed, it is determined that it is time to perform the target value correction process (YES in step S5), and the process proceeds to step S6. In this step S6, the number of pulses from the flow rate detection section 9 for the current 5 minutes is converted into an integrated flow rate and added to the integrated flow rate value measured up to the previous target value correction, and the measured integration from the start of operation is added. Use flow rate.
Then, the process proceeds to step S7, where the integrated flow rate theoretical value in the elapsed time from the start of operation is compared with the actually measured integrated flow rate value, and the target value 3 is corrected as described above. As in the above example, when an error of about −2% has occurred after 5 minutes from the start of operation, the target value “6555.7” set in step S2 is set to “656.9”. It is corrected.
Steps S3 to S7 are repeated until the liquid feeding is completed.
It becomes possible to send the liquid supply amount set within the liquid supply time set in this way.

  In the above-described embodiment, the target value correction process is executed every predetermined time, but it is not always necessary to set a constant time interval. For example, the time interval for executing the target value correction process may be changed according to the elapsed time from the start of liquid feeding.

It is a block diagram which shows the structure of one Embodiment of the roller type pump apparatus of this invention. It is a figure for demonstrating the control measurement error of an integrated flow theoretical value, an integrated flow, and its correction | amendment. It is the figure which showed the processing flow of target value correction | amendment.

Explanation of symbols

  1: set flow rate setting unit, 2: target value setting unit, 3: target value, 4: target value correcting unit, 5: comparison unit, 6: control calculation unit, 7: control output unit, 8: pump unit, 9: Flow rate detector

Claims (2)

A squeezing member that squeezes and moves a flexible tube filled with liquid to flow the liquid in the tube from upstream to downstream; and
A motor for moving the pressing member;
An operation unit for setting the amount and time of liquid delivery;
A flow rate detector that detects the amount of liquid delivered by the amount of rotation of the motor;
Target value setting means for calculating a target value of the rotation amount of the motor based on the set liquid feeding amount and liquid feeding time;
A control calculation unit that compares the target value with the detection output of the flow rate detection unit and outputs a control signal for controlling the motor so that the rotation amount of the motor becomes the target value;
Comparing the theoretical flow rate value obtained from the set liquid delivery amount and the liquid delivery time with the integrated flow rate value measured from the output of the flow rate detector, and completing the liquid delivery during the liquid delivery time. A roller type pump device comprising: target value correcting means for performing processing for correcting the target value.   The roller type pump device according to claim 1, wherein the target value correcting unit executes a process of correcting the target value every predetermined time.

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