DE102007003454B4 - Heating system for a breathing tube - Google Patents

Abstract

Heating system for a breathing tube with
A breathing tube consisting of an inspiratory tube (5) and an expiratory tube (6),
• a leading heating wire (1) extending along the inspiratory tube (5) and a return heating wire (2) extending along the expiratory tube (6), both in a first temperature zone a first heating section (3) and in a second temperature zone Forming second heating section (4), wherein the ambient temperature in the first temperature zone is lower than in the second temperature zone,
A first temperature sensor (7) located at the end of the first heating section (3) in the inspiration tube (5) and / or a second temperature sensor (8) located at the end of the second heating section (4),
A first electrical connection (10) between the leading heating wire (1) and the return heating wire (2) at the end of the first heating path (3) in the form of a diode,
A second electrical connection (11) between the leading heating wire (1) and the return heating wire (2) at the end of the second heating ...

Description

The The invention relates to the ventilation technique, in particular the heating of Breathing gas hoses.

at Mechanical ventilation is the patient to be ventilated by means of a breathing tube pneumatically connected to the ventilator. The complete breathing tube again consists of an inspiratory tube and an expiratory tube on the patient side using a so-called Y-piece pneumatically connected to each other.

Around to avoid dehydration of the airways, the respiratory gas is usually by means of of an active respiratory gas humidifier moistened between heating control and the beginning of the inspiratory tube is arranged.

If no precautions are taken, but condenses a part of the water vapor contained in the breathing gas in the breathing tube. This leads to water retention and to a reduction in the effective humidity of the patient supplied Breathing gas.

• • durch je eine sich innerhalb des Inspirations- und Exspirationsschlauches erstreckende Heizdrahtschleife
• • durch Umwicklung von Inspirations- und Exspirationsschlauch mittels einer Heizdrahtwendel, wobei die Heizdrahtwendel des Inspirationsschlauches und die Heizdrahtwendel des Exspirationsschlauches gerätefern mittels eines elektrischen Drahtes verbunden werden,

For this reason, according to the prior art, at least the inspiratory tube, but advantageously also the expiratory tube, are electrically heated. Several variants are known for this heating:

• • each with a heating wire loop extending inside the inspiratory and expiratory tubing
• By wrapping inspiratory and expiratory tubing by means of a heating wire coil, wherein the heating wire coil of the inspiratory tube and the heating coil of the expiratory tube are connected remotely by means of an electric wire,

Together All variants, it is always one of the respirator or respiratory gas humidifier (hereinafter with control unit designated) in the direction of Y-piece afferent Heating wire and one of the Y-piece to the control unit leading back Heating wire gives. Both form together with the control unit one closed circuit.

The Regulation of the breathing gas temperature is carried out according to the prior art by means of one at the end of the breathing tube, preferably the inspiratory tube or on the Y-piece arranged temperature sensor, via a temperature control circuit the heating power regulates.

In DE102004023385 A1 describes a breathing tube heater in which the temperature sensor is located in the heated area of the breathing tube.

WO2006 / 094576 A1 describes the coupling of a hose heater with a data line

In DE 4102223 a hose heater with two temperature sensors is described in which the lower control temperature of one of the two temperature control sensors is used for the heating control.

at the ventilation of infants the peculiarity is that these are used in incubators or warm beds which are normally above ambient temperature is.

The leads to, that the breathing tube is within two temperature zones extends, a cooler outside of the incubator or warm bed and a warmer one within the incubator. It must be within the warmer temperature zone located part of the breathing tube a lower heat output supplied be as the one in the cooler Temperature zone (outside of the incubator). Otherwise, the breathing gas supplied to the patient would become to warm up. In addition, that also required for the temperature control Temperature sensor can be arranged immediately in front of the incubator input got to.

in addition that comes also for the the temperature control required temperature sensor immediately must be arranged in front of the incubator entrance. He would find himself within the incubator would due to the high incubator internal temperature of the Turn off the heating control loop and condensation would occur again of water vapor in the breathing tube.

Around all possible applications to be able to cover The heating of the breathing tube must consist of two independently exist existing heating sections, of which the device is outside of the incubator (first heating section) and the other devices within of the incubator (second heating section). You can because of opposite cool the incubator to ambient temperature assume that the first heating section a greater heat output has to raise as the second heating section and that there is the case where the first heating section is switched on, the second heating section however, it is off. This requires one of the second heating section independent Control of the first heating section.

In the case of the variant of an internal heating wire loop would have a short and a long Heizdrahtschleife be provided, the short for the first heating section, the long heating loop for the first and the second heating section together. This design has the disadvantage that the double heating loops require a higher contacting effort and that in addition the free flow cross-section in the hose is reduced.

in the Trap of the variant of an outside applied heating coil would have the heating coil of the first heating section be made double after the first heating section in the heating coil for the second Go over heating section to be able to. All this is very expensive and technologically difficult to control.

task the invention is to provide a heating system for a breathing tube, with only one leading and a returning one Heating wire within each heating section independent heating of the first heating section allowed by the second heating section.

A inventive solution this Task is specified in claim 1.

The Essence of the invention is that the Hin heating wire at the end of First heating section through a first electrical connection and on End of the second heating section through a second electrical connection with the repatriate Heating wire is connected, the resistance of the first electrical Connection is a diode.

If the resistance of the first electrical connection is low, the current flows from the controller via the afferent Heating wire until the end of the first heating section, from there over the First electrical connection and the return heating wire again until to the control unit back. there Only the first heating section is heated.

is However, the resistance of the first electrical connection high, the current flows over the entire afferent Heating wire, the second electrical connection and the return Heating wire back, which heats the entire breathing tube.

used you have a diode as the first electrical connection and a wire as a second electrical connection, one obtains a particularly simple one Solution. The control of the resistor is done by polarity switching the heating voltage, because depending on the polarity, the diode is conductive or blocked. If it is conductive, it will only be the first heating section heated, because the voltage drop over the diode is so low that by the second heating section no significant Electricity flows. If the heating voltage is reversed and the diode is locked, then both the first and the second heating section heated.

Temperature sensors, which provide a signal to the heater controller are preferred near the first electrical connection and / or near the second position electrical connection.

Hinführender Heating wire and return heating wire can as extending within the breathing tube Heizdrahtschleife or in the form of a heating wire coil connected to the hose accomplished be. The heating wire coils must not on the outer surface of the Be inflated. You can also by extrusion be introduced within the hose wall. In practice However, the outside has applied heating wire coil enforced.

It is also a mixed solution possible, at the leader Heating wire extends within the breathing tube and the Returning heating wire is designed as Heizdrahtwendel and vice versa.

in the Trap of the inside extending heating wire loop needed one heating loop each and a first electrical connection for the inspiration hose and the expiratory tube. Both heating loops are at the entrance electrically connected in parallel. When using a diode as the first electrical Connection becomes this immediately at the end of the first heating section between the two wires arranged, contacted with both and then with a water and temperature resistant Encased sealant, so that both wires have only a small spherical extension exhibit. As at the end of the first heating section preferably in the inspiratory tube space for A first temperature sensor is to be provided by design measures avoid that the hot wire may be the temperature sensor touched and this leads to a faulty temperature measurement. This can z. B. happen that the heating wire near the place of Temperature sensor made thicker so that the local resistance near the temperature sensor reduces and thus the local heating power at this point is reduced. One more way possibly also in combination to increase the heating wire thickness in it, the heating wire loop in place of the first temperature sensor constructively with the breathing tube over a spacer so too connect that to the returning heating wire the maximum possible Distance from the first temperature sensor to be introduced. In this intermediate piece can also be equal to the first electrical connection z. B. in shape a diode with integrated.

Such an intermediate piece can also as Ring are performed, which contains a bore into which the first temperature sensor can be inserted and which has two contacts on its outer wall perpendicular to the bore, via the first electrical connection, for. B. a diode are connected together. The heating wire is connected to the first contact and the return heating wire is electrically connected to the second contact.

It But it can also be ensured by other constructive measures that the one inside the hose extending Heizdrahtschleife big enough Distance from the temperature sensor has.

The same measures can also at the end of the second heating section relative to one to be introduced Second temperature sensor to be made. In the simplest case However, the Heizdrahtschleife ends at a distance of a few centimeters before the second temperature sensor and the second electrical connection is in this case by the piece of heating wire. made that in the transition from leading Heating wire to the returning Heating wire is at the end of the loop.

in the Trap on the inspiratory tube and expiratory tube applied Heizdrahtwendeln extend this close to End of both hoses, the leader Heating wire z. B. by the heating wire coil of the inspiratory tube and the return heating wire are formed by the heating wire coil of the expiratory tube. At the end of the first heating section and at the end of the second heating section get both heating wires two contacts each.

The belonging together Contacting both heating coils are at the end of the first heating section on the First electrical connection and at the end of the second heating section over the Second electrical connection connected together. In the simplest Traps become the first electrical connection through a diode and the second electrical connection is formed by a simple wire and the control of the resistance of the first electrical connection done by reversing the heating voltage.

Also in the case of Heizdrahtwendeln must by constructive measures ensured be that no adulteration the measurement signal of the first temperature sensor at the end of the first Heating path takes place. A technologically simple solution exists in it, both the inspiratory tube and the expiratory tube each in two partial tubes with their own Heizdrahtwendeln split and this constructive over a To connect sleeve together. In this sleeve is additionally the Contacting housed over the two Heizdrahtwendeln the same tube connected and to which the one connection of the first electrical connection connected. additionally contains it's an opening for the introduction of the first temperature sensor. The first electrical connection is located either in one of these sockets or in the connection line between the two.

These Muff can also run like this be that it includes inspiratory tube and expiratory tube, wherein the two above-described contacts and the first or Second electrical connection including the temperature sensor are integrated.

The wire sizes the heating wires for the First and second heating sections can be different but preferably they should be the same. You reach in the latter Trap that the specific heating power when heating only the first heating sections higher and thus the heating time shorter is when heating the entire breathing tube.

The First and second electrical connection can be with the back and forth Heating wire and with the breathing hoses constructive and electric on diverse Be connected. You can either integrated in the sleeve, they can also be as firm integrated unit directly in the connecting line between the two Airbags are located.

A another possibility However, this is the first or second electrical connection or both solvable together, in particular to be pluggable. In this case contain inspiratory tube and expiratory tube at the end of the respective heating sections one contact each for the leader and returning Heating wire. The first and the second electrical connection are as a plug constructively designed so that they also have two Contain contacts with the contacts of both hoses z. B. be connected by plugging. In a particularly favorable Execution of the Invention, these connectors still contain the associated temperature sensors. This solution can for both electrical connections are chosen.

The advantage of the invention is that with only two connections for the Heizspannungsversorgung and only one leading and a returning heating wire nevertheless independent control of the heating of the breathing tube is possible and thus the condensation of water vapor in the breathing tube can be safely prevented an embodiment using a diode as a first electrical connection explained become.

1 shows the breathing tube, consisting of inspiratory tube 5 and expiratory tube 6 on the Y-piece 13 pneumatically connected to each other.

inspiration tube 5 contains the leading heating wire 1 and expiratory tube 6 the returning heating wire 2 in the form of externally applied Heizdrahtwendeln. Both hoses are divided in two and on the sleeve shown in dashed lines 12 both pneumatically and electrically interconnected.

The first inspiratory heating section 14 belongs to the first heating section 3 and the second inspiratory heating section 15 belongs to the second heating section 4 , About the contact 16 are the first inspiratory heating system 14 , the second inspiratory heating section 15 as well as the first connection of the first electrical connection 10 connected with each other. Close to the contact 16 is in the inspiratory tube 5 an opening for introducing a first temperature sensor 7 , Shortly after the end of the second inspiratory heating section 15 there is an opening for the introduction of the second temperature sensor 8th ,

The first expiratory heating line 17 belongs to the first heating section 3 and the second expiratory heating section 18 belongs to the second heating section 4 , About the contact 19 are the first expiratory heating line 17 , the second expiratory heating section 18 and the second terminal of the first electrical connection 10 connected with each other.

The first electrical connection 10 is formed by a diode. It is at positive voltage to connection 20 (related to connection 21 ) conductive.

The end of the second inspiratory heating section 15 is about the contact 22 with the second electrical connection 11 and these in turn via the contact 23 with the end of the second expiratory heating section 18 connected. The second electrical connection 11 is only formed by a wire strand.

The control unit 9 has two control inputs for the signals of the temperature sensors 7 and 8th and two heating voltage outputs connected to the terminals 20 and 21 are connected.

The mode of action is as follows:
When the temperature at the first temperature sensor 7 lower than the setpoint temperature, the controller generates 9 a heating voltage at connection 20 with positive polarity, the diode of the first electrical connection 10 is the leading and only the first inspiratory heating section 14 and the first expiratory heating section 17 heated. Because of the diode voltage of only 0.6 V is the second heating line 4 supplied electrical power negligible.

When the temperature at the first temperature sensor 7 exceeds the setpoint temperature, the controller generates 9 a heating voltage at connection 20 with negative polarity, the diode blocks and the circuit closes across both inspiratory heating sections 14 and 15 , the second electrical connection 11 and both expiratory heating sections 17 and 18 ,

Will now also the setpoint temperature at the second temperature sensor 8th reached, the control unit switches 9 completely off.

The Control algorithms for providing the heating voltage in terms of value and polarity are known in the art.

1

Hinführender heating wire

2

rear Leading heating wire

3

First heating section

4

Second heating section

5

inspiration tube

6

expiratory

7

first temperature sensor

8th

second temperature sensor

9

control unit

10

First electrical connection

11

Second electrical connection

12

sleeve

13

Y-piece

14

First inspiratory heating section

15

Second inspiratory heating section

16

contact

17

First expiratory heating section

18

Second expiratory heating section

19

contact

20

connection

21

connection

22

contact

23

contact

Claims (4)

Heating system for a breathing tube with • a breathing tube consisting of an inspiratory tube ( 5 ) and expiratory tube ( 6 ), Along the inspiratory tube ( 5 ) extending lead wire ( 1 ) and one along the expiratory tube ( 6 ) he stretching return heating wire ( 2 ), each in a first temperature zone a first heating line ( 3 ) and in a second temperature zone, a second heating section ( 4 ), wherein the ambient temperature in the first temperature zone is lower than in the second temperature zone, • one at the end of the first heating zone ( 3 ) in the inspiratory tube ( 5 ) located first temperature sensor ( 7 ) and / or one at the end of the second heating section ( 4 ) located second temperature sensor ( 8th ), • a first electrical connection ( 10 ) between the heating wire ( 1 ) and the return heating wire ( 2 ) at the end of the first heating section ( 3 ) in the form of a diode, • a second electrical connection ( 11 ) between the heating wire ( 1 ) and the return heating wire ( 2 ) at the end of the second heating section ( 4 ) and • a control unit ( 9 ), which is designed such that the diode in dependence of the output signal of the first temperature sensor ( 7 ) and / or the second temperature sensor ( 8th ) is reversed in forward or reverse direction. Heating system for a breathing tube according to claim 1, characterized in that the second electrical connection ( 11 ) is formed by a wire. Heating system for a breathing tube according to claim 1, characterized in that the second electrical connection ( 11 ) is formed by a temperature-sensitive switch. Heating system for a breathing tube according to claims 1 to 5, characterized in that the first electrical connection ( 10 ) or the second electrical connection ( 11 ) or both are releasably connected together to the breathing tubes.