JPH0630994A - Device for detecting closure in liquid transfusing pump - Google Patents

Abstract

PURPOSE:To provide a closure detecting device capable of accurately detecting the closure of tubes accompanying the increase of the internal pressure in tubes corresponding to a plurality of kinds of respective tubes. CONSTITUTION:A closure detecting device has a movable piece 42 provided movably while abutting against the outer surface of a flexible tube 18 and a holding member 46 for holding the tube 18 between itself and the movable piece 42. In the beginning of running, the movable piece 42 urged by the elastic force of a second leaf spring 49 holds the tube between itself and the holding member 46 while crushing the tube to a predetermined dimension L. When the internal pressure in the tube is increased by the closure, the tube 18 is expanded to move the movable piece 42. A magnetic sensor 50 detects the displacement DELTAL of the movable piece 42 and a microprocessor not shown judges the presence of the closure of the tube 18 on the basis of a signal from the magnetic sensor 50.

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. 6, 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. Also, as shown in FIG. 7, the door 14
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 section 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.

As the conventional blockage detection mechanism 35, there have been proposed one using a link mechanism and one using a strain gauge.

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]

However, the blockage detecting mechanism 35 using the link mechanism is 0.1 mm in the radial direction.
Since the structure for detecting a blockage by increasing the minute expansion amount of the tube 18 that expands only to a certain extent, the link mechanism necessarily becomes large in size, so that the blockage detection mechanism 35 can be downsized and the infusion pump 10 can be downsized. There was a problem that it could not be achieved. Further, there is a problem that the detection of blockage of the tube 18 becomes unstable because it is easily affected by vibration and the like.

Further, even in the blockage detecting mechanism 35 using a strain gauge, since the leaf spring is in contact with the tube 18 which swells only about 0.1 mm in the radial direction, the strain gauge with the increase in the tube internal pressure is detected. If the minute output difference is not detected, the blockage of the tube 18 cannot be accurately detected.

By the way, there are many types of the tube 18 depending on the hardness of the forming material, the diameter dimension, the wall thickness dimension, etc. Therefore, even when a certain inner pressure of the tube is applied, The way in which the tube 18 swells varies greatly depending on the type of the tube 18.

As described above, when the types of the tubes 18 are different, for example, in the blockage detection mechanism 35 using a strain gauge, the initial output value of the strain gauge at the start of operation, which is the reference, varies. Therefore, the conventional blockage detection mechanism 35 cannot perform accurate blockage detection when the type of the tube 18 is different, and requires a dedicated infusion tube set having a predetermined type of tube,
It was a cost disadvantage.

For each type of tube 18, the displacement amount of the moving member when the tube is closed, the initial output value of the strain gauge, and the output difference may be obtained in advance so that it can be adapted to a plurality of types of tubes. Conceivable. However, since the conventional blockage detection mechanism 35 originally determines whether or not the tube 18 is blocked based on the extremely small expansion amount of the tube, it is practically difficult to support a plurality of types of tubes. there were.

The present inventor provides a blockage detecting device capable of accurately detecting blockage corresponding to each of a plurality of types of tubes. Therefore, if the expansion amount of the tube itself when the blockage is large, As a result of diligent research focusing on the point that each blockage can be accurately detected, a certain pressure should be applied to the tube at the start of the standard operation, and the tube should be held in a pre-crushed state with a predetermined size. For example, it was found that the expansion amount of the tube itself when the tube was closed was large, and the present invention was completed.

Therefore, an object of the present invention is to provide a blockage detecting device which can accurately detect blockage of a tube accompanied by an increase in tube internal pressure, corresponding to each of a plurality of types of tubes.

[0017]

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,
A moving member that comes into contact with the outer surface of the tube and is movably provided, a holding member that holds the tube between the moving member, and the tube that is predetermined between the moving member and the holding member. In a state of being crushed to a size, and with the elastic means for urging an elastic force to hold the movable member under a predetermined pressure, and with the expansion of the tube due to the increase in the tube internal pressure due to the blockage. A blockage for an infusion pump, comprising: a displacement amount detection means for detecting a displacement amount of the moving moving member; and a control means for determining a blockage of the tube based on a signal from the displacement amount detection means. It is a detection device.

[0018]

At the time of starting the operation as a reference, the flexible tube is applied with a constant pressure between the holding member and the moving member to which a predetermined elastic force is applied by the elastic means. It is held in a crushed state to a predetermined size. If the tube on the downstream side of the pump section is closed during the infusion, the internal pressure of the tube gradually rises,
When the pressure that initially presses the tube is reached, the mover moves as the tube expands. At this time, since the tube is crushed in advance, the amount of expansion of the tube itself becomes relatively large, and the amount of displacement of the mover also becomes relatively large. Then, the displacement amount detecting means detects the displacement amount of the moving member, and the control means determines whether or not the tube is blocked based on the signal from the displacement amount detecting means. In this way, since the moving amount of the moving member can be made large, the displacement amount detecting means can easily detect the amount of displacement of the moving member, and even if the types of attached tubes are different, the type of each tube is different. It is possible to detect the blockage of the tube corresponding to, and a dedicated tube becomes unnecessary.

[0019]

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 detecting device 41 of this embodiment is shown in FIG.
As shown in (A) and (B), when the tube 18 is closed, it has a moving element (corresponding to a moving member) 42 that moves as the tube 18 expands. A tube mounting groove 4 for accommodating a tube 18 is provided in the main body portion 11.
3 and a through hole 44 communicating with the tube mounting groove 43 are formed, and the mover 42 is movably inserted into the through hole 44. Further, when the infusion bag 6 is replaced, a part of the drug solution 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 the chemical solution from entering the main body portion 11 through the gap between the through hole 44 and the mover 42. Therefore, the tip of the mover 42 is in contact with the outer surface of the tube 18 via the diaphragm rubber 45. The tube 18 in the tube mounting groove 43 is moved to the mover 42.
The holding member 4 on the inner surface 14a of the door for holding
6 is provided. The holding member 46 is provided on the inner surface 1 of the door.
It is configured by fixing a pressing plate 48 facing the tube mounting groove 43 to a first plate spring 47 screwed to the screw 4a.

The mover 42 has a cylindrical shape and is fixed to a second plate spring 49 (corresponding to an elastic means) screwed to the main body 11. The second leaf spring 49 urges the mover 42 with an elastic force in the direction toward the pressing plate 48. 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. Further, the strength of the elastic force of the first plate spring 47 of the holding member 46 is larger than the elastic force of the second plate spring 49, and even if the tube 18 is closed and the tube 18 is expanded, it is pressed down. The size of the plate 48 is set so as not to be separated from the tube mounting groove 43. Therefore, at the time of start of operation, which is the reference for blockage detection, as shown in FIG. 2A, the tube 18 is crushed to a predetermined dimension L equal to or smaller than the outer diameter dimension thereof, Holding plate 48
Is held between. 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 elastic means for urging the elastic force to the mover 42 is not limited to the illustrated second leaf spring 49, but may be constituted by 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 elastic means 49
The strength of the elastic force urging the moving element 42 may be adjusted.

The blockage detecting device 41 further includes a tube 18
When the tube is closed, it 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 as the tube 18 expands. The displacement amount detecting means 50 is composed of, for example, a magnetic sensor, and the moving element 42 is provided.
It has a magnet 51 that moves together with it, and a magnetic element 52 that outputs a signal according to a 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 fixed to the main body 11 via the bracket 55 with a predetermined gap from the magnet 51.

FIG. 4 shows the relationship between the tube internal pressure and the movement amount of the magnet 51 in the two types of tubes 18. As shown in the figure, the amount of movement of the mover 42, that is, the amount of movement of the magnet 51 varies depending on the nature of the tube 18, especially the hardness, even if the diameter is the same. For example, due to blockage, the tube internal pressure rises and blockage detection pressure P
In the case of 1, the movement amount of the magnet 51 in the type A tube 18 is ΔL1, but in the type B tube 18 which is softer than the type A, the magnet 51 is further moved and the movement amount is ΔL2. Conversely, in the type A tube 18, when the movement amount of the magnet 51 becomes ΔL1, the tube internal pressure rises to the occlusion detection pressure P1,
It can be detected that blockage has occurred. Also, type B tube 1
In 8, the moving amount of the magnet 51 exceeds ΔL1 and ΔL1.
When it becomes 2, the tube internal pressure has risen to the blockage detection pressure P1, and it can be detected that blockage has occurred.

FIG. 5 shows the relationship between the position of the magnet 51 and the output voltage of the magnetic element 52. Magnetic element 52
Outputs a signal according to the change in the strength of the magnetic field so as to draw a curve as shown in the figure depending on the positional relationship with the magnet 51. In order to accurately detect the displacement amount of the magnet 51 corresponding to each of the plurality of types of tubes 18, even when the types of the tubes 18 are different when the magnet 51 moves from the initial position to the closed position, It is necessary to obtain the 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.

FIG. 3 is a block diagram showing a processing circuit for judging the blockage of the tube based on the signal from the magnetic sensor.

The magnetic element 52 has a bridge structure and outputs a signal according to a change in the strength of the magnetic field to the differential amplifier 60. The magnetic element 52 is driven by the constant voltage circuit 61. The differential amplifier 60 appropriately amplifies the signal from the magnetic element 52 and outputs an output voltage having a correlation with the tube internal pressure to the A / D converter 62. The A / D converter 62 converts the signal from the differential amplifier 60 into a digital code and outputs it to the microprocessor section 63 as a control means. Storage means 64 is connected to the microprocessor section 63. The blockage detection level, that is, the threshold value data corresponding to the amount of movement of the magnet 51 when the tube internal pressure rises to the blockage detection pressure P1 and the change in the output voltage from the magnetic element 52 according to this amount of movement, Is obtained in advance for each type of. The blockage detection level for each type of tube 18 is stored in advance in the storage means 64. Further, a tube identifying unit 65 that sets the type of the attached tube 18 is connected to the microprocessor unit 63. The tube identification section 65 is configured by a setting switch (not shown) provided on the main body section 11, a DIP switch, or the like.

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, whereby 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.
In addition, the microprocessor unit 63 includes the tube identification unit 6
The type of the attached tube 18 is identified based on the signal set in 5, and the blockage detection level corresponding to the type of the tube 18 is read from the storage means 64. Then, while the normal infusion is performed, the microprocessor unit 63 determines that the signal from the A / D converter 62 is lower than the threshold data, and determines that the tube 18 is not blocked. .

When 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 also moves by the same amount, so the output signal from the magnetic element 52 is
It 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, the A / D
The signal from the converter 62 is constantly compared based on the threshold data.

As shown in FIGS. 4 and 5, when the tube 18 of type A is mounted, when the tube internal pressure rises to the blockage detection pressure P1, the moving amount of the magnet 51 is ΔL.
The output voltage from the magnetic element 52 changes by ΔV1. When the signal from the A / D converter 62 corresponding to this change becomes larger than the threshold value data, the microprocessor unit 63 determines that the type A tube 18 is blocked. Further, when the type B tube 18 is attached, when the tube internal pressure rises to the blockage detection pressure P1, the moving amount of the magnet 51 becomes ΔL2, and the output voltage from the magnetic element 52 changes by ΔV2. When the signal from the A / D converter 62 corresponding to this change becomes larger than the threshold data, the microprocessor unit 63
Determines that the type B tube 18 is blocked.

Then, the block 18 is detected by the blockage detector 41.
When the blockage is detected, the operation of the pump unit 13 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 the present embodiment, the tube 18 is held in a state of being crushed in advance to the predetermined dimension L at the time of starting the operation as the reference, so that the tube 18 is held. Tube 18 when a blockage occurs in the tube
The expansion amount ΔL of itself can be large. Since the moving amount of the moving element 42 increases accordingly, the magnetic sensor 50 can easily detect the displacement amount of the moving element 42. Accordingly, even when the type of the attached tube 18 is different, it is possible to accurately and easily detect the blockage of the tube 18 corresponding to the type of the tube 18. Further, since a dedicated infusion tube set including the tubes 18 of a predetermined type is not required, running cost is reduced and the cost is improved. Moreover,
The blockage detection device 41 can be downsized, and by extension, the infusion pump 4
A miniaturization of 0 can also be achieved.

Although the peristaltic finger type infusion pump 40 is shown, the blockage detecting device 41 of the present invention can be incorporated into other types of infusion pumps. Further, the case where the magnetic sensors 51 and 52 are shown as the displacement amount detecting means 50 is shown, but the present invention is not limited to this, and various sensors can be applied because the expansion amount of the tube 18 can be relatively large. Is.

[0037]

The blockage detecting device for an infusion pump according to the present invention comprises a moving member which is in contact with the outer surface of the tube and is movably provided, and a holding member which holds the tube between the moving member and the moving member. An elastic means for urging an elastic force to hold the tube under a predetermined pressure between the moving member and the holding member and applying a predetermined pressure to the moving member; Since it has a displacement amount detecting means for detecting the displacement amount of the moving member that moves with the expansion of the tube due to the rise of the tube, and a control means for judging the blockage of the tube based on the signal from the displacement amount detecting means. The amount of expansion of the tube itself when the tube is clogged can be large, and the amount of movement of the moving member is also large. Therefore, the displacement amount detecting means can easily detect the amount of displacement of the moving member. Thereby, even if the type of attached tube is different, the blockage detection device can accurately and easily detect blockage of the tube corresponding to each type of tube. Since it does not require a dedicated tube, the cost is excellent.

[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 block diagram showing a main part of a processing circuit of the blockage detection device.

FIG. 4 is a graph conceptually showing the relationship between the tube internal pressure and the magnet movement amount.

FIG. 5 is a graph conceptually showing the relationship between the position of the magnet and the output voltage of the magnetic element.

FIG. 6 is a perspective view showing an external shape of a general infusion pump.

FIG. 7 is a sectional view of essential parts showing a general pump part incorporated in an infusion pump.

[Explanation of symbols]

13 ... Pump part 18 ... Flexible tube 4
0 ... Infusion pump 42 ... Mover (moving member) 46 ... Holding member 4
7 ... 1st leaf spring 48 ... Retaining plate 49 ... 2nd leaf spring (resilient means) 50 ... Magnetic sensor (displacement amount detection means) 51 ... Magnet 52 ... Magnetic element 63 ... Microprocessor part (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 moving member (42), which is movably provided while being in contact with the outer surface of the tube (18), and the moving member. A holding member (46) for holding the tube (18) between (42) and the tube (18) between the moving member (42) and the holding member (46) having a predetermined dimension (L). In the state where the tube (18) is crushed into the tube, elastic force is applied to the moving member (42) to hold it by applying a predetermined pressure, and the tube (18) is increased by increasing the internal pressure of the tube due to blockage. )
A displacement amount detecting means (50) for detecting the displacement amount (ΔL) of the moving member (42) that moves with the expansion of the tube, and the tube based on a signal from the displacement amount detecting means (50). A blockage detection device for an infusion pump, comprising: a control unit (63) for determining blockage of (18).