JP4647429B2 - Roller type pump device - Google Patents

Description

  The present invention relates to a roller-type pump device that feeds liquid by squeezing and moving a liquid in a tube by a squeezing 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.
For example, in Patent Document 1, the liquid supply amount is measured by counting the output of an encoder indicating the rotation amount of the motor, and the rotation of the motor is controlled so that the liquid supply amount becomes a target flow rate value. A roller-type pump device that performs high-precision flow rate control is described.
Patent Document 2 describes a roller type pump device that issues an alarm when the number of rotations of a roller is abnormal.
Furthermore, Patent Document 3 describes a roller pump drive circuit that continuously operates a roller pump with a relatively small constant discharge pressure even when a pipe connected to the roller pump is closed. ing.
Furthermore, Patent Document 4 describes a roller pump capable of automatically controlling adjustment of occlusion (closed degree: the degree to which the roller pump squeezes the tube).
JP 2000-80989 A JP-A-6-218049 JP-A-1-317449 JP 2003-113782 A

In the conventional roller-type pump device, the amount of liquid fed is measured by counting the output of the encoder that indicates the amount of rotation of the motor that drives the pressing member (roller), so that the tube is blocked for some reason. Thus, there is a problem in that it is impossible to detect a state in which the internal pressure of the tube rises abnormally and liquid feeding cannot be performed.
Further, in order to detect that the internal pressure of the tube has risen abnormally, it has been necessary to monitor the internal pressure of the tube using a blockage detection sensor or the like.
Furthermore, when the revolving radius of the roller in the occlusion adjustment (roller tightening adjustment) is inappropriate (tightly adjusted), the tube is caught and the roller is locked, and the motor cannot rotate. There was a problem that no abnormality could be detected.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a roller type pump device that can quickly detect that the tube is closed and the occlusion is improperly adjusted with a simple configuration.

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 a set flow rate, a flow rate detection unit for detecting the liquid feed amount by the rotation amount of the motor, and calculating a target value for the rotation amount of the motor based on the set flow rate A target value setting means that outputs a control signal for controlling the motor so that the rotation amount of the motor becomes the target value by comparing the target value with the detection output of the flow rate detection unit; , WARNING when the output of the control arithmetic unit is a predetermined ratio or more larger output to the output of the proper control calculation unit obtained from the set flow rate, as adjusted for occlusion or occlusion of the tube is inappropriate It is obtained by an alarm output judging means for outputting.
Further , the output of the appropriate control calculation unit is obtained by an approximate expression indicating the set flow rate and the output of the appropriate control calculation unit corresponding thereto.
Moreover, in which it means for stopping the roller pump device when the alarm output is provided.

According to the roller type pump device of the present invention, it is possible to quickly detect that the tube closing state or the occlusion adjustment is inappropriate by monitoring the output of the control calculation unit.
Therefore, an alarm can be output before the internal pressure in the tube abnormally increases, and at the same time, the roller type pump device is stopped, so that problems such as breakage of the tube can be avoided.
In addition, because the occlusion is improperly adjusted, it is possible to detect an abnormality before the tube is caught in the roller and locked, so that the abnormal state of the roller type pump device can be detected early. Recovery becomes easy, and the operation of the roller type pump device can be facilitated.

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 calculated target value (target rotational speed of the motor). The control calculation unit 5 described later performs control so that the rotation amount of the motor becomes the target value 3.
Reference numeral 4 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 5 denotes a control calculation unit that outputs a control signal for controlling the rotation speed of the motor so that the deviation becomes as small as possible based on the deviation obtained by the comparison unit 4. Specifically, the control calculation unit 5 performs 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 5. 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.

6 monitors the PWM output value MV (n) output from the control calculation unit 5 to determine whether the PWM output value MV (n) is an abnormal value, and determines that it is abnormal. It is an alarm output determination means for outputting an alarm output to a display unit or the like when stopped, and stopping the roller pump. Although the details will be described later, this alarm output determination means is a PWM output actually output from the control calculation unit 5 with respect to the output (proper output) of the control calculation unit 5 when the occlusion is properly adjusted. When the value MV (n) exceeds a predetermined ratio (for example, 10%) or more, it is determined that there is an abnormality. In addition, the alarm output determination means 6 is provided with a display unit for displaying the PWM output value MV (n) of the control calculation unit 5 and an alarm.
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 5 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, it is determined that an abnormality has occurred when it is detected that the PWM output value MV (n) output from the control calculation unit 5 that performs PI calculation exceeds an appropriate value by a predetermined ratio or more. .

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 5 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 4. 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.
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.

Next, alarm determination processing in the alarm output determination means 6 will be described.
Table 1 shows that a 10φ tube is mounted on a roller-type pump device, and the set flow rate is changed from 0.9 [L / h] to 20 [L / h] to properly adjust the tube occlusion for each set flow rate. In the case of “normal value” in the case of performing the above, “occlusion tight adjustment” in the case of tight adjustment of the occlusion, and “blocking of the sending side tube” in the case of closing the tube on the sending side. The lower limit peak value (PWM output value when one roller is squeezing the tube) of the output MV (n) (PWM output value) of the control calculation unit 5 is listed. This data is obtained by actually measuring each condition.

FIG. 2 shows the PWM output value MV (n) from the control calculation unit 5 with respect to the flow rate setting value in each of the cases of “normal value”, “occlusion tightness adjustment” and “sending tube closing” shown in Table 1. The lower limit peak value is graphed.
Thus, at each set flow rate, in the case of “occlusion tight adjustment” and “sending tube on the delivery side”, the PWM output value MV (n) may be larger than the “normal value” by a predetermined ratio or more. I understand.
Therefore, the alarm output determination means 6 detects the actual value detected by the flow rate detection unit 9 with respect to the normal value of the PWM output value MV (n) output from the control calculation unit 5 corresponding to the set flow rate. When the flow rate value is larger than a predetermined ratio (for example, 10%) or more, it is determined to be abnormal.

Here, in the alarm output determination means 6 of the present embodiment, the normal value of the PWM output value MV (n) corresponding to the set flow rate is obtained using the approximate expression corresponding to the graph shown in FIG. I am doing so.
In this embodiment, the approximate expression for obtaining the normal value is as follows for each range of the flow rate setting value.
0.9 [L / h] to 4 [L / h]: MV (n) = 17.308x + 19.192 (2)
4 [L / h] to 8 [L / h]: MV (n) = 13.4x + 33.7 (3)
8 [L / h] to 14 [L / h]: MV (n) = 13.1x + 35.9 (4)
14 [L / h] to 20 [L / h]: MV (n) = 13.05x + 34.9 (5)

  Thus, in the present embodiment, for each inner diameter of the flexible tube, the normal value, the occlusion tightness adjustment, and the output MV (n) of the control calculation unit 5 in each case of closing the delivery side tube are calculated. Based on the measurement, an approximate expression for obtaining a normal value is determined and stored for each inner diameter of the flexible tube. And the normal value in the condition is calculated | required using the approximate expression according to the setting condition by the said setting flow volume setting part 1. FIG.

FIG. 3 is a diagram for explaining how the PWM output value MV (n) output from the control arithmetic unit 5 changes in accordance with the revolution angle (arm angle) of the roller in the pump unit 8. 3 (a) shows a state where one roller is engaged with the tube, FIG. 3 (b) shows a state where two rollers are engaged with the tube, and FIG. 3 (c) shows a PWM with respect to the angle of the arm. A change in the output value MV (n) is shown.
In this figure, 11 is the gear shaft described above, 12 is an arm provided with two rollers at both ends, 13 and 14 are rollers, 15 is a flexible tube, and 16 is a housing. The arm 12 is rotated by the rotation of the gear shaft 11, and the rollers 13 and 14 attached to both ends of the arm 12 move around the gear shaft 11 while squeezing the tube 15. Here, the angle of the arm will be described assuming that the left-right direction on the paper surface is 0 °.
FIG. 3 (a) shows a case where the angle of the arm 12 is 0 ° (or 180 °). When one roller (13 or 14) is engaged with the tube 15 as described above, the control is performed. The PWM output value MV (n) output from the calculation unit 5 is the lower limit peak value. On the other hand, FIG. 3B shows a case where the angle of the arm is 90 ° (or 270 °), and when two rollers (13 and 14) are engaged with the tube 15 in this way, Since the resistance to rotation of the motor is maximized, the PWM output value MV (n) output from the control calculation unit 5 is the upper limit peak value.

  FIG. 3C is a diagram showing the relationship between the angle of the arm 12 and the PWM output value MV (n) output from the control calculation unit 5. As shown in this figure, when the angle at which one roller squeezes the tube (0 ° to 45 °, 135 ° to 225 °, 315 ° to 360 °), MV (n) indicates the lower limit peak value. When the two rollers squeeze the tube at 90 ° and 270 °, MV (n) shows the upper limit peak value. In the process of squeezing the tube with one to two rollers (a in the figure), the lower limit peak value is increased to the upper limit peak value, and the process of squeezing the tube with two to one roller (b in the figure). It changes so that it may fall from the upper limit peak value to the lower limit peak value.

A case where the set flow rate is set to 12 [L / h] will be described as an example.
When the set flow rate is 12 [L / h], the normal value of the lower limit peak value is obtained as “194” from the approximate expression (4) as follows.
MV (n) = 13.1x + 35.9 = 13.1 x 12 + 35.9 = 193.1 ≒ 194 (rounded up after the decimal point)
If the alarm area is set to 1.1 times the normal value as a predetermined ratio,
Alarm output value = 194 x 1.1 = 213.4 ≒ 214 (rounded up after the decimal point)
It becomes. That is, an area where the lower limit peak value is “214” is set as an alarm area. A one-dot chain line in the figure indicates an alarm region corresponding to the alarm output value.

Here, the time required for one rotation of the roller when the set flow rate is 12 [L / h] is
Time required for one rotation = 3,600 [seconds] ÷ (12,000 [ml] /6.1 [ml / time]) = 1.83 [seconds / time]
Thus, the time for the roller to make a half rotation (180 °) = 0.915 seconds.
The alarm output determination means 6 is normal if the value of MV (n) satisfies the condition “MV (n) ≦ 214 (alarm output value)” even once during 0.915 seconds when the roller makes a half rotation. Judge. On the other hand, if this is not the case, that is, if “all MV (n)> 214”, it is determined that there is an abnormality, and an alarm is output to the display unit etc., and at the same time, the roller pump device is stopped.
As a result, the alarm output determination means 6 is locked by wrapping the tube in the occlusion due to improper adjustment of the occlusion of the roller type pump device, or by closing the tube outlet for some reason. It is possible to prevent accidents such as ruptures.

In the above example, if the value of MV (n) satisfies the condition “MV (n) ≦ 214 (alarm output value)” at least once, it is determined to be normal, but it continues for a predetermined time (an integral multiple of 10 ms). Time) or a predetermined number of times (for example, about 10 times) may be determined as normal when a normal condition is satisfied.
In the above, the normal value of the control calculation unit output corresponding to the set flow rate is calculated by the approximate expression, but the present invention is not limited to this, and the normal value of the control calculation unit output corresponding to each set flow rate It is also possible to store a table storing the information and obtain the value by referring to the table.
Furthermore, in the above description, the alarm output value has been described as 1.1 times the normal value. However, the alarm output value is not particularly limited, and may be a value greater than the value or a smaller value.
For example, when a roller-type pump device is used as a blood pump, a high degree of blood damage may occur if occlusion adjustment is tight. In such a case, it is possible to avoid the severe blood damage by reducing the alarm output value and performing the second occlusion adjustment.
Furthermore, the alarm output value may be determined for each tube and each set flow rate based on the actual measurement data measured for each tube used, the occlusion tightness adjustment time, and the sending side tube closing time. . An alarm output value may be determined based on the actual measurement data for each tube and each set flow rate, and the alarm output value may be used.

Furthermore, according to the roller type pump device of the present invention, uniform occlusion adjustment without individual differences can be performed as follows.
In general, when adjusting the occlusion, there is a first occlusion adjustment in which a predetermined pressure is applied to the inlet of the tube so that there is no leakage on the outlet side of the tube, and a second occlusion adjustment for tightening to take a margin for leakage. Is done. At this time, the output MV (n) of the control calculation unit 5 at the time of the first occlusion adjustment is confirmed on the display unit of the alarm output determination means 6, and the output MV ( n) The second occlusion adjustment may be performed while confirming on the display unit so as to be a value larger than the predetermined value. In this way, by performing the occlusion adjustment while confirming the output MV (n) of the control calculation unit 5 on the display unit, uniform occlusion adjustment without individual differences is possible. At this time, the output MV (n) may display an average value of a plurality of times.

It is a block diagram which shows the structure of one Embodiment of the roller type pump apparatus of this invention. It is the figure which made the graph the lower limit peak value of flow volume setting value shown in Table 1, and output MV (n) of a control calculating part. It is a figure for demonstrating the determination in an alarm output determination means, (a) is the state in which the roller of two places is biting in a tube, (b) is the state in which the roller of one place is biting in a tube, (c). FIG. 6 is a diagram illustrating an example of an output MV (n) of a control calculation unit with respect to rotation of a roller.

Explanation of symbols

  1: set flow rate setting unit, 2: target value setting unit, 3: target value, 4: comparison unit, 5: control calculation unit, 6: alarm output determination unit, 7: control output unit, 8: pump unit, 9: Flow rate detector, 11: gear shaft, 12: arm, 13, 14: roller, 15: tube, 16: housing

Claims (3)

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 set flow rate;
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 flow rate;
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;
When the output of the control calculation unit is larger than a predetermined ratio with respect to the output of the appropriate control calculation unit obtained from the set flow rate, an alarm is output as inappropriate tube occlusion or occlusion adjustment A roller-type pump device, comprising: It said output of proper control arithmetic unit, the set flow rate and roller pump apparatus according to claim 1, characterized in that it is adapted to determine the approximate expression indicating the output of the proper control operation unit corresponding thereto. 3. The roller pump device according to claim 1, further comprising means for stopping the roller pump device when the alarm is output.

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