JPH0630993A - Device for detecting closure of liquid transfusing pump - Google Patents

Abstract

PURPOSE:To provide a closure detecting device for detecting the closure of a tube provided in a liquid transfusing pump or the like, which can accurately detect the closure of the tube corresponding to a temperature change even if the environmental temperature in the use of the liquid transfusing pump is changed. CONSTITUTION:A closure detecting device has an expansion detecting means 39 for detecting the expansion of a tube 18 accompanying the increase of the internal pressure in the tube due to the closure and a thermistor 38 for detecting the working environmental temperature of a liquid transfusing pump not shown. A microprocessor section not shown corrects automatically a closure detecting level according to the temperature change of the working environment, while judging the presence of the closure of the tube 18 on the basis of the closure detecting level and the expansion of the tube 18 detected by the expansion detecting means 39.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is incorporated in an infusion pump provided with a pump portion for moving a liquid passing through the flexible tube while sequentially pressing the flexible tube, and the tube is closed downstream of the pump portion. The present invention relates to an occlusion detection device for detecting an occlusion.

[0002]

2. Description of the Related Art Conventionally, various types of infusion pumps have been used when injecting a drug solution into a living body or performing automatic drip, but it is disclosed in Japanese Patent Publication No. 61-55,393. As described above, a peristaltic finger type infusion pump is known.

In this type of infusion pump 10, as shown in FIG. 7, a tube mounting portion 12 to which a flexible tube connected to an infusion bag or the like is attached is provided on the front surface of a main body 11. . The tube mounting portion 12 is provided with a pump portion 13 for moving the liquid passing through the tube, and a door 14 facing the pump portion 13 is attached via a hinge 15 so as to be openable and closable. Furthermore, the main body 1
An operation unit 16 for setting various operating conditions and a display unit 17 for displaying an operating state and the like are provided on the front surface of the unit 1. In addition, as shown in FIG.
A back plate 19 that presses the tube 18 along the direction toward the pump portion 13 is provided on the inner surface 14 a of the above which faces the pump portion 13. A spring 20 is attached between the back plate 19 and the inner surface 14a of the door to urge an elastic force that presses the back plate 19 toward the pump portion 13.

The pump portion 13 is, as shown in FIG.
A plurality of (for example, six) fingers 25 that can move back and forth with respect to the attached tube 18 and each of these fingers 2
And a casing 26 that slidably holds 5. The casing 26 is composed of a pair of casing structures 27 that are butted against each other.
A holding groove 28 that slidably holds each finger 25 is formed in a shelf shape. Further, 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 shift the phase at a predetermined angle on the support shaft 29. It is fixed. The finger 25 has a substantially plate-like shape and has a cam hole 32 with which the eccentric cam 31 slides. At one end of the support shaft 29 protruding from the casing 26, a stepping motor,
A rotation driving means (not shown) including a timing belt and the like is connected.

Then, the rotation drive means is operated to operate the support shaft 2
When 9 is rotationally driven, each of the eccentric cams 31 fixed to the support shaft 29 with a phase shifted, rotates while slidingly contacting the inner peripheral surface of the corresponding cam hole 32 of the finger 25. As a result of this cam action, each finger 25 is moved to the holding groove 2
While sliding inside 8, the fingers 25 that have started to move forward from the top and moved to the forward limit are
The tube 18 is pressed between and to close the flow path of the tube 18. In addition, the finger 25 that has moved to the forward limit,
As the support shaft 29 further rotates, the support shaft 29 moves toward the rearward travel limit, and the blockage is released. In this way, by repeating the operation of sequentially moving from the finger 25 located above to the forward limit, the point at which the tube 18 is closed, that is, the compression point 18a, is moved downward sequentially along the longitudinal direction of the tube 18, The liquid in 18 is infused from the suction side to the discharge side.

During the infusion as described above,
A part of the tube 18 on the downstream side of the pump portion 13 is bent, twisted, or a needle attached to the tip of the tube 18 is clogged, the flow path of the tube 18 is blocked, and the internal pressure of the tube 18 rises. There was something to do.
If the rise in the tube internal pressure is left as it is, the tube 18 may be damaged. Therefore, as shown in FIG.
The tube mounting portion 12 of the infusion pump 10 includes a pump portion 1
A blockage detection mechanism 35 for detecting blockage of the tube 18 on the downstream side of 3 is provided.

The blockage detecting mechanism 35 is configured to detect blockage of the tube 18 by detecting expansion of the tube 18 due to increase in internal pressure of the tube. For example, one using a link mechanism or a strain gauge is used. Those used are proposed.

Blockage detection mechanism 35 using a link mechanism
Causes a part of the link mechanism to come into contact with the outer surface of the tube 18 to increase the expansion amount of the tube 18 due to the rise in the tube internal pressure by the link mechanism, and to detect the displacement amount of the moving member provided in the link mechanism. Thus, it is configured to detect whether or not the tube 18 is closed.

Further, in the blockage detecting mechanism 35 using a strain gauge, the strain gauge is attached to a leaf spring or the like which comes into contact with the outer surface of the tube 18, and the output of the strain gauge at the start of operation and the strain during operation It is configured to detect whether or not the tube 18 is closed by detecting the output difference from the output of the gauge.

[0010]

By the way, the swelling amount of the tube 18 also changes as the temperature around the tube 18 changes even when a certain constant tube internal pressure is applied. General vinyl chloride tubes and silicone tubes tend to soften when the temperature rises and, conversely, harden when the temperature falls. Therefore, even if a constant tube internal pressure is applied, the tube 18 tends to expand when the temperature rises, and conversely, the tube 18 becomes difficult to expand when the temperature decreases.

However, in the conventional blockage detecting mechanism 35, the blockage detection level remains constant even if the temperature around the tube 18 changes, so that the blockage of the tube 18 can be accurately detected in response to the temperature change. I couldn't. That is, when the temperature around the tube 18 becomes higher than the design temperature when the blockage detection level is determined,
Since the tube 18 is likely to swell, there is a risk that it may be detected that the tube has been closed even though the internal pressure of the tube has not reached the predetermined closing detection pressure. On the contrary, when the temperature around the tube 18 becomes lower than the design temperature, the tube 18 becomes difficult to swell, so that the tube is blocked even though the tube internal pressure reaches the predetermined blockage detection pressure. There is a risk that it will be detected.

Therefore, it is an object of the present invention to provide a blockage detecting device capable of accurately detecting the blockage of a tube in response to the temperature change even if the temperature of the environment in which the infusion pump is used changes. To do.

[0013]

The present invention for achieving the above object is incorporated in an infusion pump having a pump portion for moving a liquid passing through a flexible tube while sequentially pressing the flexible tube, and A blockage detection device for detecting blockage of the tube on the downstream side of the pump section,
Expansion detection means for detecting expansion of the tube due to rise in tube internal pressure due to blockage, temperature detection means for detecting use environment temperature of the infusion pump, and closure based on the use environment temperature detected by the temperature detection means A blockage detection for an infusion pump, comprising a control unit that changes a detection level and compares the blockage detection level with the expansion of the tube detected by the expansion detection unit to determine blockage of the tube. It is a device.

[0014]

The control means changes the blockage detection level based on the operating environment temperature detected by the temperature detection means, and compares the changed blockage detection level with the expansion of the tube detected by the expansion detection means. , Determine if the tube is blocked. In this way, since the presence or absence of blockage is determined while changing the blockage detection level, even if the temperature of the environment in which the infusion pump is used changes, the blockage of the tube can be detected in response to this temperature change. Can be done accurately. For example, when the environmental temperature becomes high, the blockage detection level can be changed to a higher level to detect the blockage of the tube at a predetermined blockage detection pressure corresponding to the tube that is likely to expand. Further, when the environmental temperature becomes low, the blockage detection level is changed to a lower level, so that the blockage of the tube can be detected at a predetermined blockage detection pressure corresponding to the tube that is less likely to swell.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an example of use of an infusion pump incorporating the blockage detection device of the present invention, and FIGS. 2 (A) and 2 (B) are
FIG. 8 is a cross-sectional view of essential parts showing an operating state of the blockage detection device shown in FIG. 1, the same members as those shown in FIGS. 6 and 7 are designated by the same reference numerals, and the description thereof will be partially omitted. .

As shown in FIG. 1, in the medical field,
Infusion system 5 for infusing a parenteral liquid such as a nutrient solution, a medicinal solution, or a physiological saline solution to a patient 8 in order to administer the liquid.
Is used. The infusion system 5 includes an infusion bag 6 that stores a nutrient solution and the like, and an infusion pump 40 that injects the nutrient solution and the like. A flexible tube 18 is connected to the infusion bag 6 via a drip cylinder 7, and a tube mounting portion 12 to which the tube 18 is attached is provided on the front surface of the main body 11 of the infusion pump 40. This tube mounting part 1
2, the tube 1 on the downstream side of the pump unit 13
A blockage detection device 41 for detecting blockage 8 is provided.

The blockage detection device 41 of this embodiment has a configuration shown in FIG.
As shown in (A) and (B), expansion detection means 39 for detecting expansion of the tube 18 due to increase in tube internal pressure due to blockage is provided, and the expansion detection means 39 is provided when the tube 18 is blocked. It has a moving element 42 that moves as the tube 18 expands. Body 1
1 includes a tube mounting groove 43 in which the tube 18 is accommodated.
And a through hole 44 communicating with the tube mounting groove 43 is formed, and the mover 42 is movably inserted into the through hole 44. In addition, when the infusion bag 6 is replaced, a part of the liquid medicine may leak and travel along the outer surface of the tube 18 to reach the tube mounting groove 43. A diaphragm rubber 45 is attached to the tube mounting groove 43 in order to prevent it from penetrating into the main body 11 through a gap between the tube mounting groove 43 and the tube mounting groove 43. Therefore, the tip of the mover 42 is in contact with the outer surface of the tube 18 via the diaphragm rubber 45.
In order to hold the tube 18 in the tube mounting groove 43 with the moving element 42, a holding member 46 is provided on the inner surface 14a of the door. The holding member 46 is provided on the inner surface 14a of the door.
The first plate spring 47 screwed to the
It is configured by fixing the pressing plate 48 facing the No. 3.

The mover 42 has a cylindrical shape and is fixed to a second leaf spring 49 screwed to the main body 11. The second leaf spring 49 pushes the pressing plate 4 against the mover 42.
It exerts an elastic force in the direction toward 8. The strength of the elastic force of the second leaf spring 49 is larger than the elastic force of the material of the tube 18 itself, and hinders the smooth expansion of the tube 18 when the tube 18 is closed and the tube internal pressure rises. Not set to a size. The strength of the elastic force of the first leaf spring 47 of the holding member 46 is determined by the second leaf spring 4
The elastic force is larger than the elastic force of No. 9 and is set to a size such that the pressing plate 48 does not separate from the tube mounting groove 43 even if the tube 18 is closed and the tube 18 is expanded. Therefore, as shown in FIG.
Is held between the mover 42 and the pressing plate 48 in a state of being crushed to a predetermined dimension L which is equal to or smaller than the outer diameter dimension thereof. On the other hand, at the time when the tube 18 is closed, the tube 18 expands by the size ΔL in accordance with the increase in the tube internal pressure, and the mover 42 moves to the second position due to the expanded tube 18 as shown in FIG. The leaf spring 49 moves ΔL upward in the figure against the resilience of the leaf spring 49.

The structure for urging the elastic force to the mover 42 is not limited to the illustrated second plate spring 49, and may be, for example, a spring or the like. Further, the shapes and structures of the mover 42 and the holding member 46 are not limited to those shown in the figures, and can be changed as appropriate. Furthermore, the strength of the elastic force urged by the moving element 42 may be adjusted.

The expansion detecting means 39 of the blockage detecting device 41 is
Further, when the tube 18 is closed, the tube 18
Has a displacement amount detecting means 50 for detecting the amount of movement, that is, the amount of displacement of the moving element 42 that moves with the expansion.
The displacement amount detecting means 50 is composed of, for example, a magnetic sensor, and is a magnet 51 that moves together with the moving element 42.
And a magnetic element 52 that outputs a signal according to the change in the strength of the magnetic field due to the movement of the magnet 51. The magnet 51 is held by an adjusting screw 53 attached to a screw hole (not shown) formed in the second plate spring 49, and headed to the head of the adjusting screw 53 by a spring 54 provided between the magnet 51 and the second plate spring 49. Has been blasted in the direction. Therefore, by rotating the adjusting screw 53, the holding position of the magnet 51 can be adjusted in the vertical direction in the drawing. On the other hand, the magnetic element 52 is separated from the magnet 51 by a predetermined gap, and the main body 11 is separated via the bracket 55.
It is fixed to. The magnetic element 52 outputs a signal corresponding to a change in the strength of the magnetic field so as to draw a predetermined curve depending on the positional relationship with the magnet 51. However, in order to accurately detect the displacement amount of the magnet 51, When 51 moves from the initial position to the closed position, it is necessary to obtain a change in the output voltage from the magnetic element 52 in a linear range. Therefore, as described above, the holding position of the magnet 51 is adjustable so as to be within the linear range.

By the way, the infusion pump 40 is usually about 10 ° C.
Although it is used in a temperature range of about 40 ° C. to about 40 ° C., as shown in FIG. 3, even when a constant tube internal pressure Pi acts, the hardness of the tube 18 changes in the temperature range and the tube 18 bulges. The amount ΔL is different. Figure 3
As is clearer, the tube 18 softens and easily expands when the temperature rises, and the tube 1 decreases when the temperature decreases.
8 tends to harden and become difficult to swell.

Since the temperature greatly affects the amount of expansion of the tube 18 as described above, the blockage detecting device 41 of this embodiment has the temperature detecting means 38 for detecting the ambient temperature of the infusion pump 40. . This temperature detecting means 38
Is, for example, a thermistor, a thermocouple, or the like. As shown in FIG. 1 and FIG. 2, the thermistor 38 as a temperature detecting means has a portion capable of detecting the ambient temperature of the infusion pump 40, for example, the outer surface of the main body portion 11, preferably the tube mounting portion 12, and more preferably. Is attached to the inner surface 14 a of the door adjacent to the mover 42.

FIG. 4 shows changes in the bulging rate ΔL / Pi (ratio of the bulging amount ΔL and the tube internal pressure Pi) of the tube obtained from FIG. 3 with respect to temperature. As is clear from FIG. 4, the swelling rate ΔL / Pi approximates a linear function with respect to temperature and is given by the following equation (1). ΔL / Pi = Kn · t + a (1) Here, ΔL: tube swelling amount Pi: tube internal pressure Kn: proportional constant a: swelling rate at 0 ° C. t: temperature (° C.).

The holding position of the magnet 51 is adjusted by the adjusting screw 53.
The output voltage from the magnetic element 52 is adjusted in a linear range when the magnet 51 moves as the tube 18 bulges.

At this time, the bulge amount Δ of the tube 18
L is proportional to the change ΔVd in the detected voltage due to the change in the resistance of the magnetic element 52, which is given by the following equation (2). ΔVd / ΔL = Km (2) Here, Km is a proportional constant.

From equations (1) and (2), ΔVd = Km.ΔL = Km. (Kn.t + a) .Pi = a.Km. (1 + Kn / a.t) .Pi (3)

From the equation (3), if the tube internal pressure (closure detection pressure) to be detected is Pth, the corresponding detection voltage ΔVth is ΔVth = a · Km · (1 + Kn / a · t) · Pth. (4) Therefore, if the constants a, Km, and Kn are set in advance by experiments or the like, it is possible to detect the presence or absence of blockage of the tube 18 at a predetermined blockage detection pressure Pth even if the temperature changes.

FIG. 5 shows the tube 18 based on the signal from the magnetic sensor 50 and the signal from the thermistor 38.
FIG. 3 is a block diagram showing a processing circuit for determining whether the blockage has occurred.

The magnetic element 52 constitutes a bridge with resistors R1, R2 and R3, and a constant voltage is applied to the bridge from the constant voltage circuit 61. The movement of the magnet 51 changes the resistance of the magnetic element 52, and outputs a signal corresponding to this change to the differential amplifier 60. The differential amplifier 60 is
The signal from the magnetic element 52 is appropriately amplified and an output voltage having a correlation with the tube internal pressure is output to the A / D converter 62. The A / D converter 62 converts the detection signal from the differential amplifier 60 into a digital code and outputs it to the microprocessor section 63 as a control means. On the other hand, the thermistor 38 constitutes a bridge with the resistors R4, R5 and R6, and a constant voltage is applied to the bridge from the constant voltage circuit 64. The resistance of the thermistor 38 changes due to the temperature change, and a signal corresponding to this change is output to the differential amplifier 65. The differential amplifier 65 appropriately amplifies the signal from the thermistor 38 and outputs an output voltage having a correlation with temperature to the A / D converter 66. In the A / D converter 66,
Converts the signal from the differential amplifier 65 into a digital code,
Output to the microprocessor unit 63. A storage unit 67 is connected to the microprocessor unit 63, and the storage unit 67 is connected to the above formula (4).
The constant value and the blockage detection pressure Pth to be detected are stored. Then, the microprocessor unit 63 detects the ambient temperature based on the information from the thermistor 38, calculates ΔVth from the equation (4) based on this temperature, and calculates the signal from the A / D converter 62 ΔVth. When it exceeds the value, it is determined that the tube 18 is blocked. In this way, the calculated ΔVth functions as a blockage detection level for detecting blockage, that is, a threshold value.

Next, the operation of this embodiment will be described.

When the tube 18 is mounted on the tube mounting portion 12 and the infusion pump 40 is driven, the pump portion 13 sequentially repeats the operation of sequentially moving from the finger 25 located above to the forward limit, and thereby the tube 18 is moved. The closing point, that is, the compression closing point 18a, moves sequentially downward along the longitudinal direction of the tube 18, and the liquid in the tube 18 is infused from the suction side to the discharge side.

At the start of the operation, the blockage detecting device 41 is in the state shown in FIG.
Is held between the pressing plate 48 and the moving element 42 to which the elastic force of the second plate spring 49 is urged, in a state of being crushed to a predetermined dimension L that is equal to or less than the outer diameter dimension. Further, the moving element 42 and the magnet 51 do not move while the normal infusion is performed, and the output signal from the magnetic element 52 is constant.
Further, the microprocessor unit 63 detects the ambient temperature from the information from the thermistor 38 and calculates ΔVth from the equation (4) based on this temperature. While the normal infusion is being performed, the microprocessor unit 63
It is determined that the signal from the A / D converter 62 does not exceed the calculated ΔVth, and it is determined that the tube 18 is not blocked.

If the flow path of the tube 18 on the downstream side of the pump portion 13 is closed during the infusion,
The internal pressure of the tube 18 gradually rises. Then,
As shown in FIG. 2 (B), the tube 18 that has been crushed to the predetermined dimension L expands by the dimension ΔL in response to the increase in the tube internal pressure against the elastic force of the second leaf spring, The mover is also pushed upward by the same amount in the figure. At this time, since the tube 18 is in a previously crushed state at the time of starting the operation as the reference, the expansion amount of the tube 18 itself can be made relatively large, and accordingly, the movement of the mover 42 is increased. The displacement amount is also relatively large. When the mover 42 moves in this way, the magnet 51
Since the same amount is also moved, the output signal from the magnetic element 52 changes according to the change in the strength of the magnetic field due to the movement of the magnet 51. In the microprocessor unit 63, A
The signal from the / D converter 62 is constantly compared with the calculated ΔVth.

When the tube internal pressure exceeds the blockage detection pressure Pth, the signal from the A / D converter 62 calculates ΔVt.
It becomes larger than h, and the microprocessor unit 63 determines that the tube 18 is blocked. Since ΔVth obtained from the equation (4) is compared with the signal from the A / D converter 62, even if the operating environment temperature changes, ΔVth, that is, the threshold value is not automatically changed. This is corrected, and the blockage of the tube 18 is reliably detected at the predetermined blockage detection pressure Pth. When the blockage detection device 41 detects the blockage of the tube 18, the operation of the pump unit 13 is performed. It is forcibly stopped or an alarm is issued. As a result, the reliability of the infusion pump 40 is enhanced, the nurse can engage in other tasks with peace of mind, and the patient receiving the infusion can receive treatment with peace of mind.

As described above, according to the blockage detecting device 41 of this embodiment, the microprocessor unit 63 adjusts the temperature around the tube detected by the thermistor 38,
Since the blockage detection level is automatically corrected and the presence or absence of blockage is determined based on the corrected blockage detection level, even when the temperature of the environment in which the infusion pump 40 is used is different from the design temperature, It is possible to accurately detect the blockage of the tube 18 in response to the temperature change of the environment. That is, when the temperature around the tube 18 becomes high, the equation (4)
As is apparent from the above, since the threshold value is corrected to a higher value, it is possible to detect the blockage of the tube 18 with a predetermined blockage detection pressure Pth corresponding to the tube 18 that is likely to expand. On the contrary, when the temperature around the tube 18 becomes low, the threshold value is corrected to be low, so that the predetermined blockage detection pressure Pth corresponding to the tube 18 that is less likely to expand.
Can detect the blockage of the tube 18.

FIG. 6 is a block diagram showing another processing circuit for determining the blockage of the tube based on the signal from the magnetic sensor 50 and the signal from the thermistor 38.

Similar to the processing circuit described above, the magnetic element 52
Constitute a bridge and are driven by the constant voltage circuit 61. The differential amplifier 60 also appropriately amplifies the signal from the magnetic element 52 to obtain a detection signal 70. The differential amplifier 60 is adjusted so that the detection signal 70 when the tube 18 is attached to the infusion pump 40 becomes zero. The detection signal 70 from the differential amplifier 60 is output to the comparator 71. On the other hand, the thermistor 38 forms a combined resistance RC together with the correction resistance Rs. This combined resistance RC changes according to the following equation (5) depending on the temperature.

RC = RC0 (1−Kc · t) (5) where RC0 is the value of Rc at 0 ° C. Kc is a proportional constant.

The output Vc of the amplifier 72 connected to the thermistor 38 is given by the following equation (6).

Vc = -RF / RC * (-V) = RF / (RC0 (1-Kc * t)) * V = RF / RC0 (1 + Kc * t) * V (6) where (Kc * t) ) ² <1 where -V: reference voltage.

Therefore, as is clear from the comparison between the equations (4) and (6), the output Vc from the amplifier 72 becomes equal to ΔVth by selecting the values of RF / RC0, Kc and V. Become. Therefore, in the control means including the comparator 71 and the amplifier 72, the detected voltage 70 and the temperature-compensated Vc output from the amplifier 72 are compared with each other by the comparator 7.
The blockage of the tube 18 can be detected by comparing 1 and the detection signal 73 corresponding thereto is output.

Even if the processing circuit is constructed as described above, it has a temperature correction function as in the above-described embodiment, and therefore even when the environmental temperature in which the infusion pump 40 is used is different from the design temperature. The blockage of the tube 18 can be accurately detected according to the temperature change of the environment in which the infusion pump 40 is used.

Although the peristaltic finger type infusion pump 40 is shown, the blockage detection device 41 of the present invention can be incorporated into other types of infusion pumps. Further, the expansion detecting means 39 is not limited to that shown in the drawings, and any structure having a conventionally known link mechanism or a strain gauge may be used as long as the expansion of the tube 18 due to the increase in the tube internal pressure due to the blockage can be detected. It may be configured to have.

[0044]

The blockage detecting device for an infusion pump according to the present invention comprises an expansion detecting means for detecting the expansion of the tube due to an increase in the internal pressure of the tube due to the blockage, and a temperature detecting means for detecting the ambient temperature of the infusion pump. A blockage detection level is changed based on the operating environment temperature detected by the temperature detection means, and the blockage detection level is compared with the expansion of the tube detected by the expansion detection means to determine the blockage of the tube. Since it has a control means, even if the environmental temperature in which the infusion pump is used changes, the presence or absence of blockage will be determined while the blockage detection level is changed accordingly, and the temperature of tube blockage detection will be changed. There is an effect that it can be performed accurately corresponding to.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of use of an infusion pump in which the blockage detection device of the present invention is incorporated.

2 (A) and 2 (B) show the blockage detection device shown in FIG. 1, and FIG. 2 (A) is a cross-sectional view of essential parts showing an operating state at the start of operation. B) is a sectional view of an essential part showing an operating state when the tube is closed

FIG. 3 is a graph showing the relationship between the tube internal pressure and the tube bulge amount due to temperature changes.

FIG. 4 is a graph showing the relationship between temperature and the expansion coefficient of a tube.

FIG. 5 is a block diagram showing an embodiment of a processing circuit of the blockage detection device.

FIG. 6 is a block diagram showing another embodiment of the processing circuit of the blockage detection device.

FIG. 7 is a perspective view showing an external shape of a general infusion pump.

FIG. 8 is a cross-sectional view of essential parts showing a general pump part incorporated in an infusion pump.

[Explanation of symbols]

13 ... Pump part 18 ... Flexible tube 38 ... Thermistor (temperature detection means) 39 ... Expansion detection means 40 ... Infusion pump 63 ... Microprocessor part (control means) 71 ... Comparator (control means) 72 ... Amplifier (control means)

Claims (1)

[Claims] 1. An infusion pump (40) having a pump section (13) for moving a liquid passing through the flexible tube (18) while sequentially pressing the flexible tube (18). 13)
A blockage detection device for detecting blockage of the tube (18) on the downstream side of the tube (18) according to an increase in tube internal pressure due to blockage.
Expansion detection means (39) for detecting the expansion of the, the temperature detection means (38) for detecting the use environment temperature of the infusion pump (40), based on the use environment temperature detected by the temperature detection means (38) The blockage detection level is changed by a control means (63, which judges the blockage of the tube (18) by comparing the blockage detection level with the expansion of the tube (18) detected by the expansion detection means (39). (71, 72)), and a blockage detecting device for an infusion pump.