Device and method for tempering and humidifying gas, especially respiratory air

p0001BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a device for the temperature control and humidification of gas, in particular of breathing air, the device comprising a liquid reservoir and a humidification chamber having an inflow and an outflow for the gas and a movement device for moving the liquid through the gas . The invention also relates to a corresponding method.

p0002Such a device is to be used in particular for the ventilation of a patient. In the context of the invention described here, the term "breathing" also means any type of respiratory therapy and "patients" means both humans and animals.

p0003Such breathing of a patient is usually performed with the aid of an apparatus comprising a breathing tube, a respiratory flow generating device and a humidifier for the breathing gas. The breathing gas is supplied from a reservoir to the respiratory current generating device and also has a connection for the breathing tube.

p0004A breathing current generating device is essentially a functional unit which regulates the respiratory gas to be applied to a patient in pressure and / or volume flow, for example with valves or a bellows. However, this functional unit can also be part of a larger apparatus.

p0005The breathing gas will usually be air / oxygen mixtures, but it is also possible to administer specific other gas mixtures.

p0006The liquid, which is present in the liquid reservoir and with which the humidification of the gas or the air takes place, is usually water. Within the scope of the present invention, however, other liquids or mixtures of liquids are also conceivable, as well as those to which drugs have been added.

p0007Patients who are ventilated by devices are usually inserted into the air tube through which ventilation is performed. This tube sits at the end of a breathing tube, through which a respiratory-current generating device delivers respiratory gas to the patient. Additional ventilation hoses can end on the tube.

p0008The delivery of breathing gas via the respiratory current generating device is usually effected as a function of different parameters, which can be set on the respiratory flow generating device in a manner which is adapted to the needs and can then be automatically maintained by this device or can be varied as required. Depending on the device or the parameters set, the respiratory flow varies considerably over the course of the respiratory phase. In previously known ventilation systems, this leads to considerable problems:

p0009Through the tube in the air tube, the natural function of the nose, mouth and throat space is bypassed, which in normal breathing heats and breathes the breathing gas. In the case of respiratory therapy, such as, for example, the continuous overpressure therapy with facial mask (CPAP), the nasopharyngeal space is also traversed by the breathing gas, but in comparison to the natural self-breathing of a patient, Application of dry cold gases often have undesirable side effects. This includes irritation and inflammation as well as dehydration and clogging of the upper airways.

p0010In order to overcome this problem, the related gas, which comes from a reservoir such as a gas bottle or a compressed gas line, or is also taken from the environment as a reservoir by a blower, bellows or the like, and which is usually relatively dry, Artificially moistened and heated.

p0011As far as possible, the attempt is made to reach the natural conditions, ie to control the breathing gas to a temperature corresponding to the body temperature and to moisten it so that it is largely saturated. In particular, a relative humidity of approximately 95-100% is aimed at.

p0012This is particularly difficult with the above-described strongly fluctuating gas streams, as occur during spontaneous breathing or artificial respiration.

p0013A similar problem is also found in other medical fields in which a device according to the invention can be used, such as, for example, in laparoscopy. In this case, gas (often carbon dioxide) is introduced into the body, for example into the abdominal cavity, for the purpose of expanding body cavities. In this and similar applications, too, an irritation of mucous membranes which have hitherto frequently escaped, as well as their drying out and cooling down, can preferably be prevented by tempering and moistening, preferably to a substantial saturation of the related gas.

p0014It should be taken into account that fluctuating gas flows are also to be determined in this application, since the introduction or removal of instruments into or out of body openings necessitates a rapid adjustment of the gas flow in order to keep the pressure in a body cavity constant.

p0015In principle, various techniques and methods are known for heating and humidifying gas to a preset value in the above-mentioned applications. In the following, some methods and devices are described for this:<ul><li><u>Pass-over evaporator</u> (For example, <patcit id="pcit0001" dnum="DE3830314"><text>DE 38 30 314</text></patcit>) "</li></ul>

p0016In this known device, a gas to be tempered and moistened is passed over the surface of a heated water bath and is thereby tempered and moistened at the same time. The liquid surface cools as a result of the evaporation of the water and is only slowly exchanged by warmer, rising water.

p0017Due to the size limited by the application in a ventilation system, the exchange area between the liquid and the gas flowing over it is very small. The described cooling of the surface and the resultant slow transport of energy by warmer water to the surface also results in an emissive gas having smaller or larger temperature differences relative to the liquid, depending on the gas flow quantity. Therefore, in a device of this type, the temperature of the liquid is also adjusted to an average gas flow quantity and moves with conventional devices between approximately 40 ° C. and approximately 80 ° C. Highly fluctuating gas flows, as are normal in the ventilations according to the above, thus have either an excessively high or too low a temperature, and also an excessively high or too low humidity in the instantaneous value consideration. This can only be corrected by a drastic change in the water temperature which is theoretically possible.

Membrane evaporator

(E.g., DE 43 03 645 or similar to US 6068609)

p0018In a device of this type, gas is passed over the surface of a structural body protruding from tempered liquid. The structural body thereby sucks the required liquid, eg by means of capillary forces. Only the evaporated liquid is replaced by new ones. The disadvantage here is in particular that the resulting evaporation cooling and the only small energy boost by warmer water results in a similar problem to that of the pass-over evaporators discussed above so that ultimately a variable gas flow can neither be constantly moistened nor can be constantly controlled. It is only mentioned on the margins that the structural elements mentioned are often only conditionally stable and their autoclavability, which is desirable for medical use, is generally restricted.

Hollow fiber humidifier

(For example, DE 197 27 884)

p0019Semi-permeable hollow fibers (eg of PTFE) are arranged in bundles in such a way that a gas to be tempered and moistened flows, for example, through the lumens of the hollow fibers, on the outer sides of which the liquid required for the moistening is present. A disadvantage of these humidifiers is both the often limited durability as well as the limited mechanical and thermal loadability of the hollow fibers. In addition, there is not sufficient heat conductivity through the wall of the hollow fibers, so that the heat recovery is not sufficient to compensate for the evaporation temperatures. Thus, in particular in the case of relatively high gas flows, a desired heating of the gas is not to be ensured, which at the same time is accompanied by a deficient humidification of the gas. Here, too, the heating of the water can be corrected by heating the water, but the forced heating of the fibers does not lead to a constant humidification, since the energy output of the heating elements can hardly be adjusted in the speed of the gas flow change for technical reasons.

High temperature evaporator

(For example, DE 43 12 793 or US 2162 462)

p0020In such devices, small amounts of liquid are evaporated at temperatures of about 80 ° C. to about 130 ° C. and mixed with the flowing gas. This provides both the required energy for tempering the gas and the required moisture. A disadvantage of these devices is, in particular, the high technical outlay, which is additionally associated with an increased technical risk, in particular with regard to the risks of pressure and heat. Furthermore, the devices have the disadvantage that the regulation of the required evaporation quantity can only take place with a time delay. Thus, even with such a device, a constant temperature control and humidification can not be achieved with strongly fluctuating gas flow.

Bubbling humidifier

(For example DE 37 30 551 or US 3 987 133)

p0021In devices of this type, gas is bubbled through a tempered liquid, whereby it is moistened and tempered. The disadvantage of this method is, in particular, the process-induced high gas flow resistance, since at least one differential pressure corresponding to the entry depth of the gas in the liquid must always be overcome. This is especially disadvantageous in spontaneously breathing patients.

Ultrasonic nebulizer

(For example, DE 197 26 110)

p0022In such devices, liquid is excited to vibrations in the ultrasonic range, which results in the smallest droplets being able to be separated from the liquid and entrained by the gas stream. In this case, it is particularly disadvantageous that it is in no way a liquid which is present in a molecular form, but is much larger units (aerosols). As a result, various pathogens can be transported in an undesirable manner. Furthermore, this method also poses a risk that too much or too little moisture is emitted, especially in the case of intermittent or fluctuating gas flows.

Pressure atomizer

(E.g., DE 28 34 622)

p0023In the case of devices of this type, a liquid is evaporated, which leads to the formation of very small droplets and not, for example, of molecular water vapor. The disadvantages of these pressure atomizers thus correspond to the previously discussed ultrasonic nebulizer.

Artificial noses

( "Heat and moisture exchanger" (HME, eg DE 94 17 169), filter mats, etc.

p0024In the case of artificial noses, the gas is passed over a very humidified surface, which essentially achieves a moisture saturation of the gas stream. In artificial noses, heat and moisture are supplied via the exhaled air of a patient. In filter mats, eg from the climatic engineering, heat and moisture are supplied, for example, via a water bath. Filtering of the gas is carried out simultaneously via these filter mats.

p0025A disadvantage of these known devices is, in particular, that the evaporation cooling leads to a gas flow-dependent cooling so that humidification and temperature control can not be constant with a variable gas flow. Furthermore, the disadvantage of these devices is that the substances retained during the filtration process increase the flow resistance of the filter mats for the gas in the course of the period of use, which is particularly undesirable in the medical report. Also, due to the principle-based arrangement of the HMEs in the patient's and patient's area, the dead space is disadvantageously enlarged. This may cause a patient to breathe a large portion of the air that he has just exhaled before.

Booster systems

(E.g., DE 44 32 907)

p0026In these systems an attempt is made to compensate for the insufficient efficiency of artificial noses (HME) by means of the supply of liquid and heat. This requires a technically quite complex control. In addition, temperature and humidity can not be kept constant due to the system, even in the case of strongly fluctuating gas flow, since even a very good regulation can hardly compensate for the evaporation losses that occur due to time delays. The above-described disadvantageous dead space, as well as the disadvantageous size and the disadvantageous weight, are further enlarged in these systems by further elements not explained in detail here.

Combination of previously discussed methods

(DE 296 12 115).

p0027In this combined process, the gas is first superheated and moistened and then cooled to the target temperature in a subsequent second stage by means of constant temperature metal ribs or the like. Excess moisture in the gas is then condensed as condensate from the tempered metal ribs and returned to the humidifier. A disadvantage of this method is, above all, that the gas is first supplied with more energy in the form of moisture and temperature than is necessary for ventilation.

p0028Apart from the fact that this is energetically unfavorable, there is also the risk that a patient can be permanently damaged in the cooling stage in the event of a malfunction.

Air humidifier with rotating plate stack

(For example, DE 37 35 219)

p0029In such systems, plate piles rotate such that the plates immerse in water during a part of their circulation and are thereby wetted. The gas flows past these plate stacks by means of a fan and is thus to be cleaned and moistened by particles. In these devices, a non-volatile agent is to be added to the liquid to reduce the surface tension in order to actually achieve sufficient plate wetting. These and similar devices are provided, in particular, for residential air-conditioning and have no possibility of tempering the gas. In addition, the dimensioning and the rotational speed of the plates is in no way suitable to constantly humidify a variable gas flow or even to saturate it with a liquid.

p0030It must be summarized, therefore, that in the prior art there are no processes and systems for the temperature control and humidification of gases which would be suitable for application in the case of strongly fluctuating or intermittent gas flow. In the devices known hitherto, considerable fluctuations in the temperature and humidity of the emitted gas occur.

p0031A further disadvantage of the known devices is that they partly considerably degrade or even completely prevent the precision of measuring and regulating processes which are desired for ventilation. For example, there are methods and sensor systems for ventilation, which are as direct as possible a coupling of a respiratory flow generating device Or a sensor to a patient in order to administer to him the required breathing gas in a predetermined constant quality and quantity, and in particular also with precise volume flows.

p0032The humidifiers known today, which are arranged between a respiratory flow generating device and the patient, are disadvantageous in that an additional compressible volume of a considerable size is introduced into the breathing circuit.

p0033A further disadvantage of the known humidifiers is also the pressure gradient which prevails between their inlet and outlet in some conventional humidifiers: since the pressure of the respiratory gas supplied to the patient (breathing gas level) is only slightly higher than the ambient pressure (usually a maximum of approximately 0.1 bar ), This pressure gradient leads to the fact that the pressure prevailing at the patient does not lie precisely on the respiratory-current generating device itself. This has the danger of malfunctions and inaccuracies in the regulation as a consequence.

p0034It is therefore an object of the present invention to further develop devices as described above in such a way that the mentioned disadvantages are eliminated and, in particular, gas is to be constantly controlled to a preset value independently of flow fluctuations of the gas stream To a relative humidity of about 95-100%.

p0035This object is achieved according to the invention by providing a device for the temperature control and humidification of gas with a liquid reservoir as well as a humidifying chamber which has an inflow and a discharge for the gas as well as a movement device; Adapted to move the liquid through the gas, and a controlled heater adapted to heat the liquid.

p0036The invention has several advantages over the prior art:

p0037On the one hand, there is the possibility of having two elements through the moving device and the controlled heating, by means of which a regulation of the temperature control and humidification can be achieved.

p0038On the other hand, a relatively intensive temperature control and humidification can be achieved by means of these two elements, which are to be controlled independently of each other, so that the device can be designed to be relatively compact.

p0039Furthermore, such a device is robust and reliable in operation and can thus also be reliably used in continuous operation.

p0040No aerosols are produced, but the gas is saturated with vaporous liquid. It is also important that the control of the temperature control and humidification is easy to read via the moving device and the controlled heating.

p0041Advantageously, the humidification chamber is formed as a sprinkling chamber. In a sprinkling chamber, the liquid is moved through the gas. The temperature of the gas flowing therethrough can easily approach the temperature of the water, whereby the saturation of the gas flowing through with the evaporation of the liquid is simultaneously produced. The gas emerging from the sprinkling chamber is moisture-saturated, ie it has a relative humidity of approximately 95-100% and has a temperature close to the predetermined water temperature.

p0042Advantageously, a filling with a large surface is also provided in the sprinkling chamber. The filling is brought to the same temperature as the liquid by the liquid passing over it continuously. The filling can thus serve as a buffer in order to be able to provide energy in the short term for a greater demand for evaporation energy in the case of strongly fluctuating gas streams and thus strongly changing needs for evaporation energy.

p0043For this filling, for example, an aluminum knit or a stainless steel wool has also been shown to be particularly suitable, as well as a pack of metal balls, in particular steel balls. These materials have a high energy storage capacity combined with the ability to quickly release energy again.

p0044However, other open-pore structures for the filling material are also conceivable.

p0045It is essential that the filling is selected in such a way that the volume flow of the breathing gas is not substantially hindered by the flow of flow, and thus, even with a maximum volume flow, there is hardly any noticeable pressure difference between the inflow and the outflow of the gas.

p0046In a further preferred embodiment, such a filling can also be simply removed from the sprinkling chamber for the purpose of exchange or sterilization.

p0047Furthermore, it is essential that the movement device, in order to move the liquid through the gas, which is preferably a pump, which conducts temperature-controlled liquid in an amount through the gas and thus, if appropriate, via a filling in the sprinkling chamber, Which is so large that it can provide the energy both to raise the temperature of the gas flowing therethrough and to provide the required evaporation energy substantially. Thus, to achieve that at maximum flow through the sprinkler element the gas flowing through is heated to almost liquid temperature and with a drained saturated r relative humidity of almost 100%.

p0048It has proved to be advantageous to pressurize the humidification chamber in certain applications.

p0049This makes it possible to supply humidified air to a downstream respiratory-current generating device, and humidification does not have to take place between the respiratory-current generating device and the patient. This not only avoids dead space (compressible volume) in the region between the respiratory flow generating device and the patient but also an installation of the device in the breathing tube which runs between the respiratory flow generating device and the patient which could cause an additional undesired pressure gradient there.

p0050Moreover, humidification under excess pressure in the apparatus can humidify and store a substantially larger amount of gas than in a humidifier arranged in the region of lower pressure between the respiratory flow generator and the patient. This results in a positive-looking buffering of heated and moistened gas and thus compensation for short-term fluctuating volumetric flows can occur.

p0051Complex control is not required. This also means a considerable structural simplification which leads to cost savings.

p0052In order to adjust precisely the temperature to the required value from the respiratory current generating device to the patient, it is furthermore proposed to provide the respiratory tube itself with a corresponding heating element which is placed, for example, in the inner tube. However, it is also possible to incorporate the heating element in particular into the wall of the breathing hose. The integration of the heating element into the breathing tube has the advantage that the provided heating element is in direct contact with the breathing gas and can be adjusted directly to the desired final temperature, which makes it easier to always achieve an even temperature of the gas in the patient in the case of strongly fluctuating volumetric flows have.

p0053It should also be mentioned that in the case of a humidification chamber which is pressurized, the liquid and thus also the humidifying process is adjusted to a temperature which is selected in such a way that even after the subsequent expansion of the moisture-enriched and heated gas to respiratory or ambient pressure and A defined humidity is reached at a desired temperature (ventilation temperature). This is preferably also close to the saturation limit in respiratory cases.

p0054In principle, the temperature in the humidification chamber which is under pressure is both dependent on the pressure prevailing in the humidifier as well as on the temperature desired by the patient and on the relative humidity of a breathing gas desired by the patient. Depending on the application, the relative relative humidity may be less than 100%.

p0055It is also within the scope of the invention, in the case of fluctuating gas flows, to vary the overpressure correspondingly to fluctuations in order to offer a respiratory gas, which is constantly temperature-controlled and moisturized after the expansion, on the patient's side.

p0056For the liquid, which is not required for the humidification of the breathing gas itself, but serves merely for its heating and thus loses temperature in the sprinkling element, in a preferred embodiment it is provided to return to the liquid reservoir. From there, it can be fed back to the irrigation element again after heating via the regulated heating system.

p0057A filter is thereby integrated into a circuit formed in this way, by means of which it is ensured that both the circulating liquid and the breathing gas are kept substantially free of germs.

p0058In a preferred embodiment, the liquid reservoir, which also has the regulated heating for the liquid, is pressureless and is connected to the sprinkling element via a pump (as a movement device for the liquid). By regulating this pump, the quantity of the circulated liquid can be adapted to the corresponding demand. If a pressure reducer is also provided in the circulating circuit, an uninterrupted operation of the temperature control and moistening device can also be possible during a necessary refilling of liquid into the liquid reservoir, even in the case of an humidification chamber which is under an overpressure.

p0059Of course, the sprinkler humidifier described can also be used in the low-pressure range. The advantages outlined remain intact. However, it may be that, when integrated into a breathing apparatus, undesirable dead spaces result.

p0060An alternative embodiment comprises, as a movement device for the liquid, no pump, but a rotating body immersed in the liquid in the liquid reservoir. This is preferably a stack of mutually spaced plates which rotate about a horizontal axis and drag liquid from the liquid reservoir into the gas stream, where the liquid then evaporates and leads to a humidification of the gas. Such a device can be designed to be particularly compact and the rotation of the plate stack can be regulated particularly easily by means of an electric motor so that, even in the case of fluctuating gas streams, it is possible to react rapidly to different requirements for liquid for gas humidification.

p0061Otherwise, the device is characterized essentially by the fact that the observance of the target parameters can be achieved by an easy-to-implement monitoring of the liquid level in the liquid reservoir as well as the temperature and the pressure in the humidification chamber together with a measurement of the temperature and, if appropriate, relative humidity of a patient supplied to a patient Breathing gas.

p0062Further advantages and features of the invention will become apparent from the following description of exemplary embodiments. FIG<dl id="dl0001" compact="compact"><dt>FIG</dt><dd>The principle sketch of a device for tempering and humidifying gas for ventilating a patient with an overpressure humidification;</dd><dt>FIG</dt><dd>An alternative embodiment of a device for regulating and humidifying gas without a high-pressure region;</dd><dt>FIG</dt><dd>A further alternative embodiment with a movement device in the form of a plate stack.</dd></dl>

p0063<figref idrefs="f0001">FIG</figref> Shows an exemplary embodiment of a humidification device according to the invention, in this case with positioning in front of the respiratory current generating device.

p0064In the exemplary embodiment shown, breathing gas is taken from a reservoir 1, for example a compressed gas bottle or a compressed gas line. This usually very dry compressed gas is fed via a humidifier 2 to a respiratory current generating device 3. Here, the supplied breathing gas is relieved to a pressure (breathing gas level) which is required for a respiration or a breathing therapy and which can be somewhat above the ambient pressure. The Breathing gas is then passed to a patient 5 in a temperature-controlled manner via a heatable breathing tube 4 connected to the respiratory current generating device.

p0065The supply from the respiratory current generating device 3 to the patient 5 takes place with a very low compressible volume of the breathing system.

p0066It is important that the breathing gas supplied to the patient is precisely and constant a nominal moisture content Temperature, typically near the saturation limit, ie, almost 100% at a temperature of about 37 ° C. In addition, patient ventilation must be performed without interruption.

p0067For this purpose, heated liquid is fed to the humidifier 2 via a line 6, which in this exemplary embodiment is water of approximately 72 ° C., which reaches the annular chamber 7 in the humidifier 2. If, moreover, water is mentioned here, it should again be pointed out that the use of other suitable fluids is also possible, which can be selected by a person skilled in the art on the basis of his knowledge. It is also possible for the liquid or, in the embodiment described here, Can be added without mentioning separately in the following.

p0068From the annular chamber 7, the temperature-controlled water runs via a sieve bottom 8 into a sprinkling chamber 9, which contains a filling 10. In this exemplary embodiment, this filling consists of solid structural elements with a large surface area and large recesses.

p0069While the water flows out of the annular chamber 7 downwards over the large surface into the bottom chamber 11 of the humidifier 2, it heats and fills the filling 10. At the same time, breathing gas coming from the reservoir 1 flows through the filling 10 in the opposite direction And at the same time absorbs moisture, so that it can be conducted almost saturated via a collection chamber 12 to the respiratory flow generating device 3.

p0070At this point, it should also be pointed out that the volume flow of heated water supplied to the humidifier is considerably higher than the volume flow which would be required in the humidifier only for the saturation of the breathing gas stream with moisture. This ensures that the gas and liquid are not significantly cooled in the contact area of ​​the gas, which ensures the required temperature increase of the flow of breathing gas.

p0071In the example shown here, the above-described process takes place under pressure, ie the water and thus the breathing gas have a pressure of about 4.5 bar at a temperature of about 72 ° C.

p0072As a result of the relaxation of the breathing gas from about 4.5 bar at about 72 ° C. to slightly above ambient pressure and cooling to a temperature of about 37 ° C., the breathing gas maintains its relative humidity of almost 100%.

p0073Other temperature / pressure combinations are also possible in the humidifier, as long as it is ensured that, even after the pressure has been released to the breathing pressure level, the breathing gas has the target moisture corresponding to the predefined parameters at the set target temperature.

p0074As already explained, in the humidifier 2, the liquid, which is fed via the filling 10, is collected in the bottom chamber 11. From here, it flows, controlled by way of a valve 13, through a return line 14 into a storage container 15. A pressure reducer 16 is provided in the return line 14 so that the storage container 15 as such is unpressurized. In the exemplary embodiment illustrated here, the pressure reducer is designed as a throttle.

p0075In the storage tank 15, the water temperature in the present example is kept at 72 ° C. by means of a controlled heating 17, such temperature regulation being relatively easy to solve constructively. The water thus heated is pumped via an optional filter 18 from a pump 19 through the line 6 into the annular chamber 7 of the humidifier 2.

p0076The optional filter 18 ensures that the circulated water is free of particles and microorganisms, and thus also the breathing gas supplied to the respiratory-current generating device 3 can essentially be regarded as free of germs.

p0077By means of the pump 19 and the valve 13 or the pressure reducer 16, the reservoir 15 can be designed without pressure and can be refilled at any time.

p0078An alternative embodiment is shown <figref idrefs="f0002">FIG</figref>. In this case, the humidifier 2 is connected, as in the described methods according to the prior art, between the respiratory current generating device 3 and the patient 5.

p0079In order to keep the compressible volume and the size small, the device is designed for gas flow (0 to approx. 180 l / min) which is customary in ventilation technology and conforming to standard humidifying capacities.

p0080The humidifier 2 is supplied with a temperature-controlled liquid, which in this exemplary embodiment is again water of about 37 ° C., which reaches the distribution chamber 7 in the humidifier 2.

p0081From the distribution chamber 7, the temperature-controlled water runs via a sieve base 8 into a sprinkling chamber 9 which contains a filling 10. In this exemplary embodiment, this filling consists of solid structural elements with a large surface area and large recesses.

p0082In the sense of a simplification of the device, it is conceivable to dispense with the filling 10 and to let the liquid droplets emerging from the sieve bottom 8 simply fall through the sprinkling chamber 9. This may, however, be considered to be advantageous for cleaning and conditioning, but it must be taken into account that the volume of the sprinkling chamber and the circulated liquid quantity per time can be substantially increased under the same demands on the humidification capacity.

p0083While the water from the distribution chamber 7 trickles downwards over the large surface into the bottom chamber 11 of the humidifier 2, it heats and fills the filling 10. Simultaneously, breathing gas coming from the breathing-current generating device 3 flows in the direction of the filling through the filling 10. This breathing gas heats up And at the same time absorbs moisture, so that it can be guided to the patient 5 almost in a saturated manner with a relative humidity of approximately 95-100% via the collection chamber 12.

p0084In order to avoid condensation, a technically known, regulated-heated breathing tube 4 is preferably used. It is important here that no point of the wall in the region of the gas stream is colder than the saturation temperature of the gases in order to prevent condensation. Usually, the gas in this breathing tube 4 is further heated, for example to 40 ° C., in order to prevent condensation also on the last stretch to the patient, in particular the unheated tube.

p0085It should also be mentioned that, depending on the functional principle of the respective respiratory-current generating device 3, only a single breathing tube 4, or several, can be used, wherein the exhaled air of the patient may also be supplied to the respiratory-current generating device. In these cases, the above-mentioned comments on the necessity and / or the possibilities of the hose heating also refer to all further hoses and hose sections in which the condensation problem can exist.

p0086As already explained, in the humidifier 2, the liquid, which is fed via the filling 10, is collected in the bottom chamber 11, which acts as a liquid reservoir.

p0087In this case, the liquid is held at 37 ° C. by means of a regulated heating system 17 at a water temperature in the present example, such a temperature control being relatively easy to solve constructively. The water thus heated is pumped via an optional filter 18 from a pump 19 through the line 6 into the distribution chamber 7 of the humidifier 2.

p0088The optional filter 18 ensures that the recirculated water is free of particles and microorganisms and thus also the breathing gas supplied to the patient 5 can essentially be regarded as free from germs. Alternatively or additionally, the device may be provided with an antimicrobial surface.

p0089Via a valve 21, the liquid levels in the bottom chamber 11 can be regulated at a constant level via a liquid storage container 20, for example an infusion bottle. For this purpose, this valve can also be designed as a float valve. It is important here that the hydrostatic differential pressure between the liquid storage container 20 and the bottom chamber 11 is always greater than the highest-reaching respiratory pressure. For practical purposes it is advisable to position the storage container at a height of at least 1 m above the floor chamber.

p0090A further valve 22 serves as a bypass valve between the gas inlet and the gas outlet of the humidifier 2. This ensures that ventilation is not hindered if the differential pressure is too high, for example due to a defect in the humidifier, and thus serves patient safety.

p0091Water, which is integrated into the collecting zone 12, is separated from the water trap 23, and excess water carried in the air is separated and returned to the bottom chamber 11.

p0092For regulating the humidification process and for monitoring the function, the control and monitoring device 29 is connected to the humidifier 2 and the patient 5 via various sensors, control and regulating lines. The patient temperature is determined via the temperature sensor 24, which can be designed, for example, as a commercially available temperature probe. This can enter the humidification process as the target variable. Alternatively, this target temperature can also be predetermined by the communication with another device, eg a monitoring monitor. The liquid temperature is detected via a further temperature sensor 26 and then regulated with the heating element 17.

p0093The third temperature sensor 25 detects the temperature of the incoming gas. In the event of an excessive increase in the liquid level in the bottom chamber 11 as a result of a failure of the valve 21 or a failure of the pump 19, a control and monitoring device 29 can detect the excessively high liquid levels via the temperature change at this sensor 25. In this event, a bypass valve 22 opens, whereupon a significant temperature decrease is to be measured at a temperature sensor 27, which detects the temperature at the gas outlet. This safety mechanism can be checked by a selective shut-off of the pump 19 and the consequent increase in the liquid level.

p0094The control and monitoring device 29 is connected to the humidifier 2 via a transponder 28, which is permanently connected to the humidifier 2, in order to identify it and to monitor its lifetime.

p0095The power consumption of the pump 19 can also be monitored in the control and monitoring device 29. Since the power consumption is associated with the level of the liquid level in the bottom chamber 11, an excessively low liquid level, for example caused by an empty supply container 20 or a defective valve 21, or a defective liquid circulation, for example by clogging the screen bottom 8, be recognized.

p0096Alternatively, an arrangement according to FIG <figref idrefs="f0003">FIG</figref> conceivable:

p0097Here, the humidifier 2 is correspondingly located <figref idrefs="f0002">FIG</figref> Between the breathing-current generating device 3 and the patient 5. The liquid is located in a floor chamber 11 and is controlled to constant temperature via the heater 17.

p0098The liquid level in the bottom chamber 11 becomes correspondingly <figref idrefs="f0002">FIG</figref> Is maintained at a constant level by means of the supply container 20 and the valve 21.

p0099Solid structural elements of the exchange element 30 are cyclic, in particular by means of rotation, at least partially into the liquid, so that a sufficiently frequent exchange of the water takes place in the contact region. In this case, the amount of liquid entrained during immersion can be substantially influenced by the geometrical design of the structural elements, for example by radial ribs or the like. Furthermore, the energy transport can be increased by a high rotational speed.

p0100In the described embodiments, for example according to the <figref idrefs="f0001">FIGS</figref>, <figref idrefs="f0002">2</figref> and <figref idrefs="f0003">3</figref> As well as correct dimensioning, a strongly fluctuating and interrupted gas flow can essentially be brought to constant temperature and saturation without, for example, the risk of overheating of the gas after interruption or too low a humidity in the event of a sudden high gas flow.

p0101For the solution of the object according to the invention, it is necessary for this purpose to dimension the contact area of ​​liquid and gas in such a way that the desired material and energy exchange takes place almost completely even in the maximum peak current flow provided in the application Can This dimensioning can be tested by constantly guiding the maximum peak current flow through the device according to the invention. When the dimensioning is correct, the gas temperature, after passing through the humidification chamber, almost corresponds to the liquid temperature before it enters the humidification chamber.

p0102The entrainment of water droplets in the gas stream is prevented by appropriate measures (eg enlargement of the flow cross-section).

p0103The connection of heated hoses for further transport of the gas can effectively prevent condensation in the hose.

p0104If a relative humidity of less than 100% is desired, this can be achieved by means of the downstream circuit of a suitable heating element for the humidified gas. The gas in the humidifier according to the invention is brought to the temperature and saturation whose absolute content of moisture corresponds to the requirements. The gas leaving the humidifier is then brought to the actual target temperature and relative target moisture via a downstream gas heating or by mixing with dry gas. As a result, the generation of different gas temperatures and humidities can be achieved.

p0105The device according to the invention is suitable not only for ventilation technology, but also for all applications in which a variable gas stream of particles is to be cleaned and / or brought to a constant temperature and humidity. Examples include the insufflation of gases into body cavities (eg CO₂ The air-conditioning of rooms (eg buildings, vehicles, airplanes, etc.), either alone or in combination with air-conditioning systems, etc.