WO2005089847A1 - Bellows tube for respiration circuit - Google Patents

Abstract

A bellows tube (respiration tube) for respiration circuits capable of realizing low costs while retaining safety. Hot water is fed from the end of a first flow channel (50) into the interior thereof. The hot water fed in reaches the downstream end (the right-hand end in Fig. 2) of the first flow channel (50), where it enters a second flow channel (60), and returns to the original position. During this time, the hot water spirally moves between an inner tube (10) and an outer tube (20), thus heating the wall surface of the inner tube (10). This heating prevents a decrease in the expiration or inspiration temperature in the bellows tube interior. Further, energizing an electric wire (70) provides heating by which a decrease in the expiration or inspiration temperature in the bellows interior can also be prevented. Further, even if the electric wire (70) is overheated, part of the heat can be absorbed by the hot water in the flow channel. Furthermore, detection of the amount of hot water returned makes it possible to detect damage to the bellows tube.

Description

 Specification

 Flexible tube for breathing circuit

 Technical field

 The present invention relates to a flexible tube for a breathing circuit.

 Background art

 [0002] Fig. 1 shows an example of a conventional breathing circuit (artificial respirator). This breathing circuit also includes a pump device 1, a breathing tube 2, a mouthpiece (so-called Y-piece) 3, and a force. The respiratory tube 2 includes an inspiratory tube 2a and an expiratory tube 2b.

 [0003] According to this device, the intake air sent from the pump device 1 can be supplied to the subject via the intake pipe 2a and the mouthpiece 3. On the other hand, the exhaled breath from which the subject's power has also been sent out is collected by the pump device 1 via the mouse piece 3 and the exhalation tube 2b. Various serpentine tubes are used as the inhalation tube 2a or the expiration tube 2b.

 [0004] In this device, the intake air sent from the pump device 1 is usually adjusted to a temperature of 35 ° C and a humidity of 100%. The exhaled breath delivered from the subject is usually at a temperature of 37. C, humidity 100%. For this reason, when the breathing circuit is at room temperature, dew condensation occurs inside the inhalation tube 2a and the expiration tube 2b due to a decrease in the temperature of inspiration or expiration. Water generated by condensation should not enter the target. Therefore, conventionally, the water traps 4 are attached to the middle of the inhalation tube 2a and the middle of the expiration tube 2b, respectively. The water trap 4 has a flow path for discharging water in the pipe to the outside.

 However, in the conventional breathing circuit, the inside and the outside of the breathing tube 2 are connected via the water trap 4. Therefore, in the conventional breathing circuit, care must be taken to prevent contamination of the inspired air by outside air.

 [0006] In order to avoid this problem, for example, as described in Patent Document 1 below, a device for mounting a heater (heating wire) along a breathing tube 2 has been proposed. According to this device, the respiratory tube 2 is heated by Joule heat to prevent the temperature in the tube from lowering and to prevent dew condensation. In this way, the installation of a water trap can be omitted.

[0007] However, since such a technique uses a heating wire as a heating means, If an excessive current flows through the heating wire, the respiratory tract may be overheated and melted. Therefore, conventionally, it has been attempted to control the heating temperature using a sensor or a control device. If this control is inaccurate, the heating wire may be overheated, so this control must be performed accurately and reliably. For this reason, the conventional device has a disadvantage that it becomes expensive.

 Patent Document 1: JP-A-6-23051

 Disclosure of the invention

 Problems to be solved by the invention

[0008] The present invention has been made based on the above circumstances, and an object of the present invention is to provide a coiled pipe (breathing pipe) for a breathing circuit that can realize low cost while maintaining safety. . Means for solving the problem

[0009] A flexible tube according to the present invention includes an inner tube, an outer tube, a first rib, and a second rib. The inner tube is inserted inside the outer tube and extends in substantially the same direction as the outer tube. The first rib and the second rib are disposed between the inner pipe and the outer pipe, and are circulated to form two spirals. A first flow path and a second flow path are formed between the inner pipe and the outer pipe by the turned first and second ribs. The first flow path and the second flow path are connected so that the fluid flowing in one of them returns from the other.

 [0010] A heating wire may be arranged on the first rib or the second rib.

 [0011] The heating wire may include a first wire body and a second wire body. The first wire may be arranged on one of the first rib and the second rib, and the second wire may be arranged on the other. The first electric wire and the second electric wire may be electrically connected to each other near the end of the inner cylinder or the outer cylinder.

[0012] A heating wire is arranged on one of the first rib and the second rib, and a thermocouple is placed on the other.

 [0013] A thermocouple may be arranged on the first rib or the second rib.

 [0014] The electric wire may be arranged inside the first rib or the second rib.

[0015] The thermocouple may be arranged inside the first rib or the second rib. [0016] A breathing circuit according to the present invention includes any one of the above-described flexible tubes.

 The invention's effect

 According to the present invention, it is possible to provide a coil for a breathing circuit, which can realize low cost while maintaining safety.

 BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment)

 Hereinafter, a flexible tube for a breathing circuit according to a first embodiment of the present invention will be described with reference to FIGS. In the description of this embodiment, the configuration common to the above-described conventional breathing circuit will be simplified by using the same reference numerals.

[0019] The flexible tube of the present embodiment includes an inner tube 10, an outer tube 20, a first rib 30, a second rib 40, and a first flow path.

50, a second flow path 60, and an electric wire 70 are provided as main components. The material of the inner pipe 10, the outer pipe 20, the first rib 30, and the second rib 40 is, for example, polyethylene force.

 [0020] The inner tube 10 and the outer tube 20 are both formed in a cylindrical shape. The inner tube 10 has a smaller diameter than the outer tube 20 and is inserted inside the outer tube 20. In this state, the inner pipe 10 is substantially coaxial with the outer pipe 20. The inner pipe 10 extends in substantially the same direction as the outer pipe 20. A gap is formed between the inner pipe 10 and the outer pipe 20.

 [0021] The first rib 30 and the second rib 40 are arranged between the inner pipe 10 and the outer pipe 20, and are circulated so as to form two spirals. In FIG. 2, the first ribs 30 are indicated by white circles, the second ribs 40 are indicated by black circles, and their extended states are indicated by broken lines. In this embodiment, the first rib 30 and the second rib 40 are parallel. In other words, the interval between them is constant. The first rib 30 and the second rib 40 have a substantially circular cross section in this embodiment.

 [0022] The first rib 30 and the second rib 40 thus circulated form a first flow path 50 and a second flow path 60 between the inner pipe 10 and the outer pipe 20. Therefore, the first flow path 50 and the second flow path 60 also circulate between the inner pipe 10 and the outer pipe 20 so as to form two spirals.

[0023] The first flow path 50 and the second flow path 60 are communicated with each other such that the fluid flowing in one of them returns from the other. For example, as shown in FIG. 2, the end of the first flow path 50 (the right end in FIG. 2) The force is connected to the end of the second flow path 60 (the right end in FIG. 2), and is configured to return the sent fluid. Of course, the end faces of the inner cylinder 10 and the outer cylinder 20 (the right end faces in FIG. 2) are closed so that the hot water does not leak out.

 The electric wire 70 includes a first electric wire 71 and a second electric wire 72 (see FIGS. 3 and 4). Each of these electric wires 71 and 72 is made of a conductor (for example, a -chrome wire) that can be used for resistance heating. The first electric wire 71 is arranged inside the first rib 30 (almost at the axial center position) (see FIG. 3). Similarly, the second electric wire body 72 is disposed inside the second rib 40 (almost at the axial center position) (see FIG. 4). Thus, in the present embodiment, the electric wires 70 for heating are arranged on the respective ribs 30 and 40.

 The first electric wire 71 and the second electric wire 72 are electrically connected in the vicinity of the end of the inner cylinder 10. The specific means for that purpose is optional. For example, the first rib 30 and the second rib 40 are connected at the end of the inner cylinder 10 (the right end in FIG. 1), and the first The electric wire 71 and the second electric wire 72 can be connected.

 [0026] The flexible tube 1 configured as described above can be used as a breathing tube for a breathing circuit as in the related art. When using the flexible tube of the first embodiment, it is preferable to use the control unit 8 as shown in FIG. The control unit 8 includes a water supply unit 81 and a power transmission unit 82 in addition to the pump 1 shown in FIG.

 [0027] The water supply unit 81 is connected to the first flow path 50 and the second flow path 60, and sends hot water to one of them and recovers hot water returning to the other. Such a specific design of the water supply unit 81 is easy for those skilled in the art, and therefore, detailed description is omitted.

 [0028] The energizing section 82 is electrically connected to the first electric wire 71 and the second electric wire 72, and supplies current to these.

 (Operation of First Embodiment)

Next, an example of the operation of the flexible tube according to the present embodiment will be described. First, hot water is fed into the first channel 50 from the end thereof. The temperature of the hot water is preferably high enough to prevent dew condensation inside the flexible tube. It is considered that the temperature of the hot water is preferably equal to or higher than the body temperature (for example, 40 ° C. or higher). It is considered that the upper limit of the hot water temperature should be such that the subject does not get burned. For example, it is considered preferable to be 60 ° C or less. [0030] The warm water fed into the first flow path 50 reaches an end (the right end in FIG. 2) on the downstream side of the first flow path 50, and enters the second flow path 60, where the second flow Return to water supply section 81 via road 60. During that time, the hot water heats the wall surface of the inner pipe 10 while moving spirally between the inner pipe 10 and the outer pipe 20.

 [0031] In the flexible tube of the present embodiment, this heating can prevent a decrease in the temperature of expiration or inspiration inside the flexible tube. This makes it possible to prevent dew condensation in the flexible tube.

 [0032] Further, in the flexible tube of the present embodiment, the temperature of the sent out hot water decreases in the path and returns to the original state. At this time, the going hot water and the returning hot water are adjacent to each other, so that a temperature exchange occurs between the two. For this reason, in the flexible tube of the present embodiment, the temperature gradient can be made gentler as the entire flexible tube. If the temperature gradient is steep, it is necessary to manage the humidity by assuming the lowest temperature, and at high temperatures the humidity will be low, making actual control extremely difficult. In the present embodiment, by making the temperature gradient of the entire flexible tube gentle, it is easy to control the humidity in the flexible tube, and it is possible to more effectively prevent dew condensation.

 [0033] In the flexible tube of this embodiment, the electric wire 70 is energized. It is preferable that the energization be performed after the hot water has been supplied, but it is not limited to this. By energizing the wire 70, the wire 70 is heated by resistance and generates heat. In the present embodiment, it is possible to prevent the temperature of the expiration or the inspiration inside the flexible tube from lowering by this heat generation, and to prevent the dew condensation in the flexible tube.

 Further, in the present embodiment, since the first flow path 50 and the second flow path 60 are adjacent to the first rib 30 and the second rib 40, even if the electric wire 70 is overheated, Part of the heat can be absorbed by the hot water in the flow path.

 In the present embodiment, since the hot water is in contact with almost the entire surface of the first rib 30 and the second rib 40 in the present embodiment, the amount of heat absorbed by the hot water is considerably large. Therefore, this flexible tube has the advantage of further improving the safety in which the flexible tube 70 is not damaged even if the electric wire 70 is overheated.

Further, in the present embodiment, since the electric wire 70 is disposed inside the first and second ribs 30 and 40, there is an advantage that the safety is high also from this point that the electric wire 70 is not easily short-circuited. Worried. Further, in the present embodiment, since the hot water sent into the first flow path 50 returns from the second flow path 60, if the flexible tube is damaged, the hot water returning from the second flow path 60 The amount of is reduced. If the amount of warm water returned by the second flow path 60 is detected, it is possible to detect the presence or absence of breakage of the flexible tube.

 [0038] In the first embodiment, hot water is supplied from the first flow path 50. However, a method of supplying hot water from the second flow path 60 and returning the hot water through the first flow path 50 may be used.

 Further, in the first embodiment, two ribs are formed by using two ribs. However, three or more spirals are formed by using three or more ribs, and the flow paths formed in them are formed. The hot water may be supplied or recovered by using the water.

 (Second Embodiment)

 Next, a second embodiment of the flexible tube according to the present invention will be described with reference to FIG. In this embodiment, the first electric heating element 71 and the second electric heating element 72 of the electric wire 70 are arranged substantially parallel to only one of the first rib 30 or the second rib 40 (the first rib 30 in the illustrated example). Have been. Further, in this embodiment, no electric heater is arranged on the other rib (not shown).

 In the configuration of the second embodiment, the same advantages as in the first embodiment can be obtained. Other configurations and advantages are the same as those of the first embodiment, and a detailed description thereof will be omitted.

 (Third Embodiment)

 Next, a third embodiment of the flexible tube according to the present invention will be described with reference to FIG. In this embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different portions will be described.

 In the third embodiment, a thermocouple 80 is disposed on the other of the first rib 30 and the second rib 40 (the second rib 40 in the illustrated example). The thermocouple 80 is composed of two metal wires. The tip of the thermocouple 80 (the connection point between the two metal wires) is near the tip of the coil.

 According to the third embodiment, the temperature of the flexible tube (eg, the temperature at the distal end of the flexible tube) can be measured relatively accurately by the thermocouple 80. Thereby, there is an advantage that the overheating and the temperature drop of the flexible tube can be detected, and the safety can be further improved. Other configurations and advantages are the same as those of the second embodiment, and a description thereof will not be repeated.

[0045] The description of each of the above embodiments is merely an example, and shows a configuration essential to the present invention. Not something. The configuration of each unit is not limited to the above as long as the purpose of the present invention can be achieved.

 Industrial applicability

 According to the present invention, a flexible tube that can be used as a breathing tube for a breathing circuit (artificial respirator) can be provided.

 Brief Description of Drawings

FIG. 1 is an explanatory diagram of a conventional breathing circuit.

 FIG. 2 is a cross-sectional view of a main part along an axial direction of a flexible tube according to the first embodiment of the present invention.

 FIG. 3 is an enlarged view of a main part of FIG. 2.

 FIG. 4 is an enlarged view of a main part of FIG. 2.

 FIG. 5 is a block diagram showing an example of a control unit for using the flexible tube of FIG. 2.

 FIG. 6 is an explanatory diagram of a second embodiment of the present invention, and is a diagram of a portion corresponding to FIG. 3.

 FIG. 7 is an explanatory view of a third embodiment of the present invention, showing a portion corresponding to FIG. 4. Explanation of symbols

 [0048] 10 inner tube

 20 outer tube

 30 1st rib

 40 2nd rib

 50 1st flow path

 60 2nd flow path

 70 lines

 71 First wire body

 72 Second wire body

 80 thermocouple

 9 Control unit

 91 Water supply section

Claims

The scope of the claims  [1] including an inner tube, an outer tube, a first rib, and a second rib,  The inner tube is inserted inside the outer tube and extends in substantially the same direction as the outer tube;  The first rib and the second rib are disposed between the inner tube and the outer tube, and are circulated to form two spirals;  A first flow path and a second flow path are formed between the inner pipe and the outer pipe by the turned first rib and the second rib,  The first flow path and the second flow path are communicated so that the fluid flowing through one of them flows back from the other.  A serpentine tube characterized in that:  2. The flexible tube according to claim 1, wherein a heating wire is disposed on the first rib or the second rib. [3] The heating wire includes a first wire body and a second wire body,  The first electric wire body is arranged on one of the first rib and the second rib, and the second electric wire body is arranged on the other,  The first electric wire body and the second electric wire body are electrically connected in the vicinity of the end of the inner cylinder or the outer cylinder.  3. The flexible tube according to claim 2, wherein: 4. The flexible tube according to claim 1, wherein a heating wire is disposed on one of the first rib and the second rib, and a thermocouple is disposed on the other. [5] The thermocouple is arranged on the first rib or the second rib. The serpentine tube described in 1.  6. The flexible tube according to claim 2, wherein the electric wire is disposed inside the first rib or the second rib. 7. The flexible tube according to claim 5, wherein the thermocouple is disposed inside the first rib or the second rib. [8] A breathing circuit provided with the flexible tube according to any one of claims 11 to 7.