JPH0759851A - Transfusion pump - Google Patents

Abstract

PURPOSE:To effectively utilize the efficiency of motor torque with the min. required electric power consumption by providing the transfusion pump with a circuit for changing the voltage to be applied to a stepping motor for driving a tube pressing means in response with the pulse period or pulse changeover of this stepping motor. CONSTITUTION:Eccentric cams 31 rotate respectively and respective fingers 25 successively start advancing motion from the upper part while sliding in holding grooves 28 when a fulcrum shaft 29 is rotationally driven. The fingers 25 advancing to the advance limit press tubes 15 to close flow passages. The fingers 25 advancing to the advance limit move toward the retreat limit and the closing is released according to rotation of the fulcrum shaft 29. The liquid in the tubes 15 is transfused from the suction side toward the discharge side by repeating such operation. A transfusion flow rate per unit time is set in the vermiculation type pump section by controlling the frequency of the pulses applied to the stepping motor. The control means is provided with the circuit for changing the voltage to be applied to the stepping motor in response with the pulse period or pulse changeover of the stepping motor.

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infusion pump for infusing a liquid to be transported stored in a liquid storage container.
For example, it relates to an infusion pump for administering a nutrient solution or a drug solution stored in an infusion bag to a living body.

[0002]

2. Description of the Related Art For example, in the medical field, nutrient solutions,
2. Description of the Related Art In order to administer parenteral liquids such as drug solutions and saline solutions into living bodies, medical infusion systems for infusing these liquids are used. An example of this infusion system is shown in FIG. 11, and includes an infusion bag 54 for containing a nutrient solution and the like, and an infusion pump 51 for infusing the nutrient solution and the like. As disclosed in Japanese Patent Publication No. 61-55393, the infusion pump 51 is known as a peristaltic (peristaltic finger) infusion pump, and an infusion bag is provided on the front surface of the main body 51a. A tube mounting portion 53 is provided to which a flexible tube 55 connected to a fuselage or the like is mounted. The tube mounting portion 53 is provided with a pump portion 57 for compressing and infusing the liquid passing through the tube 55 by the peristaltic motion of the finger so as to sequentially move the position where the liquid feeding tube 53 is crushed. A door 52 facing 57 is attached so as to be openable and closable. A back plate 58 that presses the tube 55 along the direction toward the pump section 57 with a predetermined pressure is provided on the inner surface 52 a of the door facing the pump section 57 . A spring is attached between the back plate 58 and the door inner surface 52 a to apply an elastic force that presses the back plate 58 toward the pump portion 57 .

The pump portion 57 of the infusion pump 51 is driven by applying pulses to a stepping motor. By controlling the rotation speed of this motor, the flow rate per unit time (for example, one hour) can be controlled within a predetermined range. can be set with In addition, since the volume of fluid to be infused per rotation of the motor drive shaft is known in advance, by counting the number of revolutions of the motor drive shaft, the integrated volume of fluid to be infused after starting the infusion can be calculated. . Furthermore, the infusion pump 51 also has a function of setting the planned infusion volume.

[0004] Once the planned amount of infusion and the flow rate of the infusion are set, the infusion sensor 59 provided in the drip tube 60 connected to the lower portion 9 of the infusion bag 14 detects the infusion for a long period of time (about 24 hours). It is configured so that infusion can be performed automatically.

This type of infusion pump 51 incorporates an infusion volume monitoring device that indicates the completion of infusion. When the total infusion amount or the total infusion amount calculated by counting the number of drops of the drug solution matches the preset planned infusion amount, the infusion is indicated by turning on a lamp or emitting a buzzer sound. It is designed to indicate completion.

[0006]

However, there is a difference between pull-in and pull-out torque characteristics of a stepping motor. When a frequency is applied, a step-out phenomenon occurs. Even in motor drive in the pull-in region, when the motor starts to rotate, the starting torque is greater than the dynamic torque. In addition, unless the voltage applied to the motor is varied according to the pulse frequency applied to the motor, there are problems such as an increase in power consumption and noise. In addition, if a constant voltage is applied without matching the motor pulse, the motor output cannot be used efficiently, resulting in an increase in power consumption and noise.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of conventional infusion pumps, and provides an infusion pump which consumes the minimum necessary power and efficiently utilizes motor torque. for the purpose.

[0008]

DISCLOSURE OF THE INVENTION To achieve the above object, the present invention provides an infusion pump for infusing a liquid to be transported stored in a liquid storage container, wherein A tube pressing means for compressing and injecting liquid by sequentially moving the crushed position of the liquid feeding tube, a driving means including a stepping motor for driving the tube pressing means, and a means for controlling the driving means. The control means comprises a circuit for changing the voltage applied to the stepping motor in response to the pulse period or pulse switching of the stepping motor.

[0009] The liquid to be transported stored in the liquid storage container is
Infusion is performed at the set infusion flow rate. By providing a circuit that changes the voltage applied to the stepping motor in response to the pulse period or pulse switching of the stepping motor, the motor torque can be efficiently extracted with the minimum necessary power consumption. An infusion pump with low noise and low power consumption can be provided.

The infusion pump that can be used in the present invention is a roller pump that moves the pressure position of the tube by a roller to infuse liquid, and a peristaltic infusion pump that sequentially moves the pressure position by means of a plurality of arranged fingers. is.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An infusion pump according to an embodiment will now be described in detail with reference to the accompanying drawings.

FIG. 1 shows a peristaltic infusion pump 1 according to the present invention.
It is a front view of. Referring to FIG. 1, reference numeral 2 denotes a first display unit showing an LED or the like for notifying an abnormality of the peristaltic infusion pump 1. Air bubbles are present in a tube (not shown) attached to the peristaltic infusion pump 1. If detected, if occlusion of the tube attached to the peristaltic infusion pump 1 is detected,
If the flow rate of the liquid in the tube attached to the peristaltic infusion pump 1 is not within the predetermined set flow rate, the peristaltic infusion pump 1
If there is no liquid in the tube attached to the peristaltic infusion pump 1, the door 12 of the peristaltic infusion pump 1 is open or not completely closed. be. 3 is the integrated amount of infusion, infusion flow rate,
This is the second display section for digitally displaying the planned infusion volume and the like. The integrated volume is calculated from the flow rate per unit time based on a pre-stored table, and is displayed. 4 is a changeover switch for switching the display of the flow rate and the expected amount on the second display section 3, 5 is an integration clear key for clearing the integrated amount, and 6 is a key for setting the number of droplets. 7a is a rough adjustment key (10
digit), and 7b is a fine adjustment key (single digit) for setting the integrated amount of infusion, the flow rate of infusion, and the expected amount of infusion. is,
Each time the lower keys of 7a and 7b are pressed, each digit is -1.
0, -1. When a flow rate setting is entered using the keys 7a and 7b, a pulse having a pulse frequency corresponding to the set flow rate is applied to the motor drive circuit to control the rotational speed of the motor drive shaft. A power key 8 indicates that the power source is a battery, and blinks when the voltage drops below a predetermined value. 9 is a fast-forward key, and infusion is performed at a predetermined flow rate while this key is pressed. 1
0 is a key for starting and stopping the infusion, and also has an alarm buzzer silence key function. 11 is a knob for opening and closing the door 12, and 13 is a grip.

The medical infusion system shown in FIG. 2 is used for injecting a medical solution (infusion solution) into a living body or for automatic drip infusion. and a peristaltic infusion pump 1 .

The infusion bag 14 contains a nutrient solution, a drug solution,
A predetermined amount of parenteral liquid such as physiological saline (corresponding to the liquid to be transported) is filled, and is locked to the top of a stand (not shown). A drip tube 21 is provided at the lower end of the infusion bag 14 .
One end of the flexible tube 15 is connected via. The drip tube 21 is provided with a droplet detection sensor 20 for detecting dripping of the liquid medicine or the like falling from the infusion bag 14 . The droplet detection sensor 20 is composed of an optical sensor 22, and the optical sensor 22 is a light-emitting element (for example, an infrared L
ED) 22a and a light receiving element (for example, a phototransistor)
22b, and is provided so that the light from the light emitting element 22a is blocked by the dropped droplets. Infusion bag 1
4, the light from the light-emitting element 22a is blocked or passes by the dropped droplets,
The light receiving element 22b outputs, for example, an OFF signal when receiving light from the light emitting element 22a, and outputs an ON signal below a preset threshold value when the light is blocked by a droplet. By counting the on-signals, the number of drops of the liquid medicine or the like is detected. In addition, the drip tube 21 is 1 for 15 drops.
The number of droplets per unit volume (for example, 1 cc) is predetermined such as cc, 19 drops for 1 cc, and 60 drops for 1 cc. Therefore, by counting the number of drops of the liquid medicine, that is, the ON signal from the light receiving element 22b, and dividing the number by the number of drops per unit volume, the integrated infusion amount can be calculated. This integrated amount is displayed on the second display section.

[0015] If the dripping of the liquid medicine or the like is not sensed even after a predetermined time has passed, that is, if the ON signal from the light receiving element 22b is not detected within the predetermined time, it is assumed that the liquid medicine or the like stored in the infusion bag 14 has run out. can judge. The infusion pump 1 is provided with a tube attachment portion 17 to which a flexible tube 15 connected to an infusion bag 14 or the like is attached. The tube mounting portion 17 is provided with a peristaltic pump portion 17 for moving the liquid medicine passing through the tube 15, and the door 1 facing the peristaltic pump portion 17 is provided.
2 is attached so that it can be freely opened and closed. Further, as shown in FIG. 2 , a back plate 18 that presses the tube 15 along the direction toward the peristaltic pump section 17 is provided on the inner surface 12 a of the door facing the pump section 17 .
Between the back plate 18 and the door inner surface 12a,
A spring (not shown) is attached to apply an elastic force that presses the back plate 18 toward the pump portion 17 with a predetermined pressing force. In addition, this peristaltic pump section 17
is covered with a waterproof sheet member to prevent the liquid medicine from entering the peristaltic pump section 17 .

As shown in FIG. 3, the peristaltic pump section 17 has a plurality of (for example, six) fingers 25 which can move forward and backward relative to the attached tube 15, and each finger can be slidably moved. and a casing 26 for holding.
The casing 26 comprises a pair of casing structures 27 abutted against each other, and within the casing 26 are retaining grooves 28 for slidably retaining each finger 25 .
is formed like a shelf. A support shaft 29 is rotatably mounted in the casing 26 via a bearing 30, and a plurality of (for example, six) eccentric cams 31 are attached to the support shaft 29 to shift the phase by a predetermined angle. is fixed. The support shaft 29 has a D-shaped cross section in order to prevent positional deviation from occurring with a timing pulley 60, which will be described later, due to rotation. Finger 25 is
A cam hole 3 having a substantially plate-like shape and with which the eccentric cam 31 slides.
2 is formed. The portion of the support shaft 29 fitted to the eccentric cam 31 may have a normal circular section other than the D-shaped section. As shown in FIG. 4, one end of the support shaft 29 protruding from the casing 26 is connected to a rotation driving means including a timing pulley 60, a timing belt 61, a motor (not shown), and the like. When the motor is actuated to rotationally drive the support shaft 29, each of the eccentric cams 31 fixed to the support shaft 29 out of phase is in sliding contact with the inner peripheral surface of the cam hole 32 of the corresponding finger 25. Rotate. As a result of this camming action, each finger 25
While sliding in the holding groove 28 , the finger 25 starts moving forward sequentially from the upper part, and the finger 25 that has moved to the limit of forward movement presses the tube 15 between itself and the back plate 18 .
occlude the flow path of Further, the finger 25 that has moved to the forward limit moves toward the backward limit as the support shaft 29 rotates further, and the blockage is released. In this way, by repeating the operation of sequentially moving the finger 25 from the upper position to the forward limit, the point at which the tube 18 is closed, that is, the closing point 18a is sequentially moved downward along the longitudinal direction of the tube 18. The liquid in 18 is infused from the suction side to the discharge side. In order to prevent pulsation, the phase of the time at which the lowest finger 25 moves to the advance limit and the uppermost finger 25 starts to advance is advanced by a predetermined time using the encoder 47 . By doing so, there is no need to additionally provide a finger for correcting pulsation.

The stepping motor can control the rotation speed of the motor drive shaft by controlling the pulse frequency of pulses applied to the motor drive circuit.

Accordingly, the peristaltic pump section 17 controls the frequency of the pulses applied to the stepping motor, thereby setting the infusion flow rate per unit time within a predetermined range. A normal rotation method in the case of two-phase excitation in a stepping motor is shown using FIGS. 9 and 10. FIG.
In FIG. 10, a magnet 71 (magnetic lines of force are perpendicular to the drive shaft 70) is provided around the drive shaft 70, and _four exciting coils D0, D1, _D2 , and _{D3 are} driven around it. They are arranged on a circle with a shift of 90 degrees around the axis 70 . The excitation coils D ₀ and D ₂ (D ₁ and D ₃ ) are wound in opposite phases. FIG. 9 shows the pulse applied to each excitation coil at the top. in short,
Since the excitation coils D ₀ and D ₃ are excited at T1,
The magnet stops in the direction of , and since the excitation coils D ₀ and D ₁ are excited at T2, the magnet stops in the direction of , and the excitation coils D ₁ and D ₂ are excited at T3, so the magnet is At T4, the excitation coils D ₂ and D ₃ are excited, so the magnet stops in the direction of . By repeating this, the motor continues to rotate.

Further, the lower portion of FIG. 9 shows changes in phase switching of voltage pulses applied to the stepping motor.
A predetermined time (Ts) from the start of driving (start SWON) is
By setting a voltage (set voltage +α) higher than the set voltage required for rotation, the motor torque is increased, and after a predetermined time (Ts) has passed, the set voltage is held only when the pulse is switched. By changing to the set voltage _VT1 time before pulse switching and setting the voltage lower than the set voltage (set voltage - β) after _VT2 time after pulse switching, constant set voltage is not always added. , the current consumption at the set flow rate can be reduced.

4 and 5, a timing pulley 60 connected to a support shaft 29 is used as transported fluid amount integrating means 45 for integrating the amount of fluid infused by the infusion pump 1. As shown in FIGS.
and an optical sensor 48 . An outer peripheral flange of the timing pulley 60 serves as an encoder 47 in which one slit 47a is formed. As shown in FIG. 5, the optical sensor 48 comprises a light emitting element (for example, an infrared LED) 48a and a light receiving element (for example, a phototransistor) 48b. ing. By integrally forming the timing pulley 60 with the conventional encoder unit, which is provided separately from the pulley, the external dimensions of the infusion pump 1 can be reduced. Further, the center hole 60a of the pulley 60 into which the support shaft 29 is inserted is formed in a D shape.
By making it non-circular, positional deviation (slip) does not occur between the pulley 60 and the support shaft 29 , and the rotation speed of the support shaft 29 can be accurately detected by the encoder 47 .
It should be noted that the present invention does not interfere at all with a pump having an encoder as a separate component. Also, the shape of the encoder is not limited to these.

The drive of the motor is transmitted to the timing belt 61, the timing pulley 60 and the support shaft 29, and when the encoder 47 rotates together with the timing pulley 60, the light from the light emitting element 47a is blocked or passes through the slit 47a. The light receiving element 48b outputs an ON signal, for example, when receiving light from the light emitting element 48a, and outputs an OFF signal when the light is blocked. By counting the ON signals, how many times the support shaft 29 has rotated is detected.
Also, the infusion amount per rotation of the support shaft 29 is known in advance. Therefore, the rotation speed of the support shaft 29, that is, the light receiving element 48b
By counting the on-signals from and multiplying this by the amount of infusion per rotation of the support shaft 29, the integrated amount of infusion is calculated. As described above, since the integrated infusion amount can be calculated based on the number of drops detected by the droplet detection sensor 20, the transported liquid amount integration means 45 may be configured by the droplet detection sensor 20. FIG.

The second display 3 preferably consists of an LED display with seven segments. Also, LED
may be arranged in a row, and a predetermined display may be indicated by lighting, extinguishing, or blinking of the LEDs. This segment can also be used to display an error. In addition, a buzzer may be provided in the time display unit to indicate an infusion completion alarm or the like, and various alarms may be identified by making the buzzer sound intermittent or continuous. Also, the display unit 3
or a buzzer may be connected to a so-called nurse call system, and a predetermined display based on the calculation result may be shown to the nurse center as well.

The operation of the infusion pump 1 will now be described with reference to the flow charts shown in FIGS.

When the program starts, various variables are initialized, and in steps S1 and S2, the planned infusion volume Q and the infusion flow rate V are set using the planned infusion volume and infusion flow rate setting keys 7a and 7b. At the same time, the planned infusion amount Q and the infusion flow rate V are stored in the storage means 62 . Further, the set planned amount Q and the infusion flow rate V are displayed on the first display section 3, respectively. Inputs by double or triple pressing of keys other than simultaneous pressing of the switching key 4 and the fine adjustment key 7b are determined to be invalid. In addition, although it is possible to input the switching key during operation of the infusion, setting of the planned infusion amount Q and
The setting of the infusion flow rate V is prohibited from interrupt processing.

When the switch 10 is operated to instruct the start of the infusion, a buzzer sounds to indicate the start of the infusion, and step S2.
Then, the pulse frequency is calculated in step S3 according to the set infusion flow rate V, and the pulses calculated in step S4 are applied to the motor drive circuit to control the rotation speed of the motor drive shaft to obtain the desired infusion solution. Infusion is started at the flow rate.

The motor drive circuit is devised as follows.

At the start of rotation of the motor, in order to compensate for the torque reduction in the high speed range (X _p·p·s· or more) of the motor, the low speed range is maintained for a predetermined time (for example, about 0.2 seconds) after the start of the infusion. The motor is driven by , and the rotation is set at a high speed. Further, a voltage obtained by adding a predetermined amount to a predetermined voltage is applied to the motor drive circuit for a predetermined time after the start of the infusion.

In order to reduce noise and power consumption, an optimum voltage is applied to the motor drive circuit according to the set flow rate.

After reaching the set rotation, the voltage is applied and held for a certain period of time (V _T1 +V _T2 ) at the time of pulse switching, and the voltage of (set voltage -β) is applied after V _T2 has elapsed from the switching. As a result, it is possible to reduce power consumption and efficiently utilize the torque of the motor.

In step S5, a timer is started immediately after the motor rotates, and it is monitored whether the timer is up for a certain period of time (for example, 0.2 seconds). If the time is not up, the process goes to the next step S6, and if the time is up, the process goes to step S10.

In step S6, it is determined whether or not the number of revolutions of the motor is equal to or greater than a certain value (for example, X _{p·p·s )} . , X _p・p・s
If it is less than that, the process proceeds to step S9.

At step S7, since the engine is in the high speed rotation range,
The calculation is once again performed in the low-speed rotation range, and then the process proceeds to step S8.

At step S8, a voltage equal to the set voltage +α is applied to the motor.

At step S9, the motor rotation speed is changed to the set rotation speed, and the process proceeds to step S10.

At step S10, the voltage applied to the motor is changed to the set voltage.

Next, FIG. 7 shows a flow chart for changing the applied voltage after a predetermined time has passed since the start and the set flow rate has been reached. In step S11, the time up of the voltage change timer is monitored, and the time up (V _T2 after pulse switching)
If the time has elapsed), the process proceeds to step S12, sets the voltage change timer, and then proceeds to step S13, where the voltage of the set voltage -β is applied to the motor for a certain period of time (from 1/4 the time required for one rotation (V _T1 +V _T2 ) minus the time) is applied.

In step S14, if the timer in step S11 does not expire, the motor applied voltage is changed to the set voltage.

Therefore, the applied voltage is changed from "set voltage -β" to "set voltage" at V _T1 time before pulse switching, and the applied voltage is changed from "set voltage" to "set voltage - β" at V _T2 time after pulse switching. β”.

FIG. 8 is a flow chart for monitoring infusion volume. In step S15, the integrated infusion amount i is equal to the planned infusion amount Q
When it is determined that the infusion is completed, the infusion completion is set in step S16, and the infusion completion alarm is also indicated to the operator by lighting a lamp or emitting a buzzer sound in step S17.

[0040] When the liquid medicine stored in the liquid storage container (infusion bag) 14 runs out during the infusion operation, it is indicated in the empty liquid display section 2d of the first display section 2, and the infusion bag 1
The replacement work of 4 is requested to the operator. In addition, if the display units 2 to 3 and buzzers are connected to a nurse call system, various information and alarms associated with the infusion work can be collectively grasped at the nurse center. It eliminates the need to look around the situation in advance.

[0041]

INDUSTRIAL APPLICABILITY As described above, according to the peristaltic infusion pump of the present embodiment, the peristaltic infusion pump injects the liquid to be transported stored in the liquid storage container, and the set infusion flow rate is maintained. a plurality of fingers for squeezing and infusing the liquid to be transported by peristaltic motion so as to sequentially move the crushing position of the liquid feeding tube according to the movement; driving means including a stepping motor for driving the fingers; and control means for controlling the driving means, and the control means comprises a circuit for changing the voltage applied to the stepping motor in response to the pulse frequency of the stepping motor or pulse switching. , compensates for the torque shortage at the start of motor rotation, and after reaching the set rotation, the voltage is changed to a low voltage after a certain period of time from pulse switching, so power consumption is minimized and each motor pulse frequency Since the set voltage is variable, unnecessary power consumption is reduced, which has the effect of suppressing unnecessary motor vibration noise.

[Brief description of the drawing]

FIG. 1 is a front view of a peristaltic infusion pump according to the present invention; FIG.

[FIG. 2] FIG. 2 is a schematic configuration diagram showing an infusion system using a peristaltic infusion pump according to the present invention.

3 is a sectional view showing the pump section shown in FIG. 1; FIG.

< Figure 4 >It is the perspective view which shows the principal part of the pump section which is shown in Figure 1.

5 is a perspective view showing an example of the infusion amount integrating means 45 shown in FIG. 1. FIG.

< Figure 6 >It is the block diagram which shows the processing circuit of this execution example.

< Figure 7 >It is the flowchart in order to change the setting voltage.

< Figure 8 >It is the flowchart which detects the end of transfusion.

< Figure 9 >It is the figure which shows the relationship between the motor pulse and the motor voltage.

< Figure 10 >It is the figure which explains the rotation angle of the motor.

FIG. 11 is a diagram representing an infusion system;

[Description of symbols] 14, 54... Infusion bag (supply source) 8, 58... Droplet detection sensor 1, 51a... Infusion pump (infusion means) 45... Infusion amount integrating means 7a, 7b... Setting keys … CPU (control means)

Claims (1)

[Claims] What is claimed is: 1. An infusion pump for infusing a liquid to be transported stored in a liquid storage container, wherein the position of the liquid to be transported is sequentially moved according to a set infusion flow rate. It comprises: tube pressing means for compressing and injecting liquid; driving means including a stepping motor for driving the tube pressing means; and control means for controlling the driving means, wherein the control means comprises the stepping motor and a circuit for changing the voltage applied to the stepping motor in response to the pulse period or pulse switching of the infusion pump.