Method for operating a cold glue application device, and device for applying cold glue

Abstract

The invention relates to a method for operating a cold glue application device (10) that has application means which are connected to a glue reservoir (16) and by means of which cold glue can be applied onto a target material. The method has the steps of: - generating humid air (18,) by means of a humid air generating device (20) which comprises an ultrasonic evaporator (22) and - supplying the generated humid air (18) as inflow air (18') to the application means, said inflow air (18') thereby flowing into the application means externally, wherein the inflow temperature, namely the temperature of the inflow air (18'), is set by means of a temperature-control device. The invention is characterized in that the inflow temperature is set to a temperature value above the dew point temperature of the inflow air (18'). The invention additionally relates to a corresponding cold glue application device (10).

Description

Field of the invention

[0001] The invention relates to a method for operating a cold glue application device which has application means connected to a glue reservoir, in particular an application nozzle, by means of which cold glue can be applied to a target material, comprising the steps: Generation of moist air Moist air generation device and supplying the generated moist air as inflow air to the application means, which are thereby externally flowed by the inflow air, wherein by means of a tempering device an inflow temperature, namely the temperature of the inflow air, is set to a temperature value above the dew point temperature of the inflow air. State of the art

[0002] A generic method for operating a cold glue application device is known from US 2008 / 041428 A1.

[0003] The application of cold glue, i.e., aqueous dispersion adhesives, to various target materials is a frequently encountered task in industry. Purely exemplary application areas include the production of folding boxes, the processing of corrugated board, the manufacture of envelopes and mailing bags, etc. The use of paper, cardboard, or carton as the target material is widespread, but by no means limiting. Automated systems are common to achieve high production volumes.

[0004] The cold glue is often transferred without direct contact between the application device and the target material by means of one or more dosing valves, which project the cold glue at predetermined times and in precisely measured portions onto the target material positioned in a transfer area. Such dosing valves usually operate electromagnetically. Other drive concepts, such as pneumatic, piezoelectric or hydraulic concepts, are also known and can generally be used. The usual dosing valve is a pressurised intermediate vessel connected to a glue reservoir via lines, which is equipped with an application nozzle that acts into the transfer area and, in particular, projects glue into the transfer area. The glue reservoir can be, for example, a pressure vessel or a suction tank of an intermediate pump.The application nozzle typically has a conical exterior and a coaxial glue channel. This can be opened and closed in the metering valve by means of an axially movable valve body. When open, the pressure in the metering valve propels glue through the glue channel into the transfer area and, in particular, onto the target material. When closed, this is not possible. Dosing is achieved by precisely adjusting the pressure, opening size, and opening time, taking into account the properties, especially the viscosity, of the glue.

[0005] Other forms of application media are also known, such as application rollers, clichés or rams.

[0006] A central problem with automated cold glue application systems is contamination of the application nozzle or, in general, the application media and / or the surrounding area. Glue splashes, so-called satellites, which can arise in a variety of ways, e.g., due to centrifugal forces, rebound, droplet formation in dead volumes, etc., dry quickly and form adhesion points for further satellites, quickly forming "beards," "threads," and similar contamination structures that hinder correct glue application. For example, targeted glue portions from an application nozzle can be deflected by such contamination structures; it is also possible for such structures to lead to smearing of applied glue on the target material.

[0007] DE 10 2016 000 064 A1 attempts to avoid the contamination problem by structuring the surface of the application nozzle. Specifically, the outer surface of the application nozzle is to be provided with a so-called "lotus effect" to allow satellites to drain off before they dry. However, it seems unlikely that a general, universally applicable "lotus structure" suitable for a wide variety of cold glues with their different viscosity properties can be found.

[0008] EP 2 386 363 A2 discloses the creation of an electric field around the nozzle outlet, electrostatically deflecting the resulting satellites onto special collection structures. These collection structures, which, by design, must be located near the transfer area, become increasingly contaminated, thus merely delaying the problem described above.

[0009] EP 1 802 191 A2 discloses equipping the application nozzle with replaceable covers, so that in case of contamination, only the cover needs to be replaced and no cleaning of the nozzle itself is required. However, replacing the cover requires a production stop and is technically complicated in complex systems with a large number of closely spaced, delicate nozzles.

[0010] EP 0 568 365 B1 discloses positioning a cleaning nozzle directly next to each application nozzle. This nozzle sprays contaminated application nozzles with cleaning fluid during system downtimes, thus cleaning them. This approach is technically highly complex, disadvantageously space-intensive, and also limited to system downtimes.

[0011] From DE 10 2020 117 624 A1 it is known to flush the nozzle of a cold glue application device with saturated moist air in order to create an atmosphere in which drying of the glue is impossible.

[0012] US 2017 / 0 030 937 A1 discloses an ultrasonic evaporator as a suitable means for generating humid air.

[0013] EP 2 878 382 A1 discloses supplying a space upstream of the nozzle opening with warm, moist air, which condenses on the cooled nozzle tip. The condensate forming at the nozzle tip is intended to loosen dried glue or prevent it from drying out in the first place. This is disadvantageous in that the glue itself, which passes through the upstream moist air space during application, can absorb moisture and thus become diluted. Another disadvantage is that the formation of condensate at the nozzle tip can lead to water droplets falling onto the target material or even being carried along by the glue. Particularly in an already humid environment, the constant emission of warm, moist air can also lead to condensation on other system components, such as the inner and outer walls of hose lines and / or on the walls of the system installation room, which worsens the working conditions for the system operators or even makes it completely impossible.This requires considerable additional ventilation and drying effort, which is not always available, especially in countries with tropical or subtropical climates. Condensation in and on hose lines, especially air hose lines, can also lead to blockages and thus disruptions in operations. Nevertheless, the basic idea of ​​exposing the application nozzle to a humid air atmosphere to prevent the adhesive from drying must be considered a promising approach.

[0014] A similar approach is pursued in DE 101 18 631 A1.

[0015] The aforementioned, generic US 2008 / 0 041 428 A1 also discloses the flushing of a nozzle head with moist air. This particularly addresses the precise control of physical moist air parameters, such as temperature and humidity content, to prevent the dew point from being reached. However, the aforementioned publication is limited to purely functional information, without disclosing any possible design implementations.

[0016] EP 3 838 430 A1 discloses a paint mixing and dosing system whose vertical outlet pipe, which combines the outlet nozzles of different paint lines, is closed during system idle times by means of a cup sealingly attached to the bottom of the pipe outlet. To prevent the paint from drying on the outlet nozzles, the cup, which is equipped with a heating device, is filled with water, which evaporates during heating and creates a moisture-saturated atmosphere in the outlet pipe. To eliminate the need for a separate water connection, the system features a Peltier cooling trap that draws in ambient air, cools it, and pumps the resulting moisture, i.e., the condensate produced during cooling, into said cup. Task

[0017] It is the object of the present invention to provide constructive implementations for carrying out the generic method so that the formation of condensate on the application means and / or other system elements, such as the moist air supply device or walls of the system installation room, is reduced. Description of the invention

[0018] This object is achieved in conjunction with the features of the preamble of claim 1 in that the moist air generating device comprises an ultrasonic evaporator, namely an open water bath, which is set into high-frequency vibrations during operation by means of an ultrasonic generator, wherein water is knocked out of the surface layer of the water bath in very small drops and, due to the large surface area of ​​the drops relative to the volume, is evaporated very quickly in the supplied air, i.e. in the supply air, and the temperature control device has a water bath cooler, by means of which the water bath is cooled in such a way that a generation temperature, namely the temperature at which the moist air is generated, is set in such a way that the inflow air has the inflow temperature.

[0019] Alternatively, the object is achieved in conjunction with the features of the preamble of claim 2 in that the moist air generating device comprises an ultrasonic evaporator, namely an open water bath which, when in operation, is set into high-frequency vibrations by means of an ultrasonic generator, wherein water is knocked out of the surface layer of the water bath in very small drops and, due to the large surface area of ​​the drops relative to the volume, is evaporated very quickly in the supplied air, i.e. in the supply air, and the tempering device has a cold trap which the moist air passes through before it is fed to the application means and in which the moist air is cooled to a target temperature which is dimensioned such that the inflow air has the inflow temperature.

[0020] Alternatively, the object is achieved in conjunction with the features of the preamble of claim 3 in that the moist air generating device comprises an ultrasonic evaporator, namely an open water bath which, during operation, is set into high-frequency vibrations by means of an ultrasonic generator, wherein water is knocked out of the surface layer of the water bath in very small drops and, due to the large surface area of ​​the drops relative to the volume, is evaporated very quickly in the supplied air, i.e. in the supply air, and the temperature control device has a supply air cooler, by means of which the supply air is cooled in such a way that a generation temperature, namely the temperature at which the moist air is generated, is set in such a way that the inflow air has the inflow temperature.

[0021] Preferred embodiments are subject of the dependent claims.

[0022] As is generally known from the prior art, the humid air is generated by means of so-called ultrasonic evaporators. These are open water baths which, when operated, are set into high-frequency vibrations by an ultrasonic generator. Water is expelled from the surface layer of the water bath in very small droplets and, due to the large surface area of ​​the droplets relative to the volume, is evaporated very quickly in the supplied air, i.e. in the supply air. In this way, saturated humid air can be created, i.e. air with a relative humidity of approximately 100%. The invention now provides for the humid air to be made available at a well-defined temperature which is selected so that the water does not condense upon contact with the application means, in particular an application nozzle. The temperature of the inflow air, i.e.The air that comes into direct contact with the application media is strongly influenced by its temperature. In particular, if the flow speed is not too fast, almost complete equalization can be assumed. In this state, the actual temperature of the moist air must still be above its dew point temperature to avoid condensation; on the other hand, it should preferably be only slightly higher so that the application media are surrounded by moist air that is as saturated as possible, thus preventing the glue from drying out. In this case, it is also preferably provided that the moist air is tempered so that condensation does not occur at other critical points on the cold glue application device or its surroundings. In this case, the moist air supply device, other surfaces of the machine and / or the walls and / or floors of the room in which the device is installed are particularly of interest.These will be referred to collectively as peripheral areas in the following.

[0023] Different technical approaches are conceivable for realizing such tempered inflow air.

[0024] In a first method variant, according to claim 2, the temperature control device has a cold trap through which the moist air passes before it is fed to the application means and in which the moist air is cooled to a target temperature which is dimensioned such that the inflow air has the inflow temperature. In this embodiment, the moist air produced is the subject of the temperature control. Before the flow passes against the application means, in particular the application nozzle, the moist air already produced is cooled by means of the cold trap, which can be Peltier-operated, for example, to such an extent that the dew point properties of the inflow air, i.e. at the location of the application means, are met.This can mean that the moist air is cooled directly to the inflow temperature; however, it is also possible to select a different target temperature if temperature changes independent of the temperature control system are to be expected on the moist air's further path to the application materials, e.g., due to contact with piping elements of the feed system. These can be factored into the selection of the target temperature of the temperature control system on a case-by-case basis. During cooling, the moist air retains its properties as saturated moist air, i.e., its relative humidity of approximately 100%; however, the absolute water load, which the air contains in the form of water vapor, decreases with temperature.Therefore - this is the essence of a cold trap - moisture precipitates in liquid form from the cooled, moist air, and condensation forms, which can be stored in the cold trap and / or removed for further use in a manner explained below. Behind the cold trap, the application media, in particular the application nozzle, continue to be exposed to saturated, moist air. In such an atmosphere around the application media, in particular the application nozzle, the glue does not dry out. However, if the inflow temperature is below the nozzle temperature, as provided for in the invention, the condensation to be avoided in the invention does not occur on the application media, in particular the application nozzle.Especially in cases where the inflow temperature is only slightly below the temperature of the application media, especially the nozzle temperature of the application nozzle, the relative humidity remains at almost 100% even in the immediate vicinity of the application media, where the inflow air warms slightly due to contact with them (without absorbing additional water). This means that the drying-prevention effect is almost completely maintained, whereas the condensation on the application media, which is recognized as a disadvantage, is avoided.

[0025] Alternatively or in addition to the cold trap, according to claim 1, the temperature control device can comprise a water bath cooler, by means of which the water bath is cooled such that a generation temperature, namely the temperature at which the moist air is generated, is set such that the inflow air has the inflow temperature. In this variant, it is not the generated moist air that is cooled, but rather the water used to generate it. This variant has advantages in terms of cooling efficiency due to the high heat capacity and thermal conductivity of liquid water. Furthermore, reference can be made to what has been said in the context of the cold trap variant.

[0026] Alternatively or (preferably) additionally, the temperature control device can be provided with a supply air cooler, by means of which the supply air is cooled in such a way that a generation temperature, namely the temperature at which the moist air is generated, is set so that the inflow air has the inflow temperature. The temperature of the supply air should also be taken into account in designs with a water bath cooler.

[0027] Condensation on peripheral surfaces can be prevented in a similar way. To do this, the inflow temperature must be set to a temperature value below, in particular at least 2°C below, and most preferably at least 5°C below, the temperature of the peripheral surface of interest in the specific case. If the moist air emerging as inflow air for the application agents subsequently spreads throughout the room and hits a peripheral surface, condensation will not occur there if the aforementioned relative temperature conditions are met.

[0028] One peripheral area where condensation prevention is particularly important is the moist air supply system itself. This can be designed, for example, as a hose or pipe system. If water condenses inside, it can lead to blockage and thus prevent or at least reduce the overall moist air supply to the application media, especially the application nozzle.

[0029] It is conceivable that the inlet temperature is fixed, for example, based on empirical values. More complex, but more advantageous in terms of the precision of the result, is a continuous setting for the inlet temperature based on repeated temperature measurements and the temperature control device is controlled to adjust the inlet temperature accordingly. With such a design, even significant changes in the operating parameters, e.g. ambient temperature differences between day and night shifts, heating due to engine operation, individual climate preferences of the operating personnel, etc., can be easily accommodated. The system can always be operated with an optimal compromise between preventing glue drying, i.e. sufficiently high moisture saturation of the inlet air, on the one hand, and avoiding condensation, i.e.On the other hand, temperature control can be carried out below the temperature of those elements where condensation is to be prevented.

[0030] As already mentioned, the skilled person can select the reference temperature depending on the requirements of the individual case. This also applies, and in particular, to the tracking operating mode outlined above. This means that, in a preferred embodiment, the temperature measurements are used to determine a nozzle temperature of an application nozzle, an air temperature of the room air at the installation location of the cold glue application device, or a temperature of a peripheral surface. For example, a wall and / or floor temperature of room boundaries at the installation location of the cold glue application device and / or a temperature of peripheral machine parts can be determined. Peripheral machine parts here include parts of the cold glue application device itself that are not central elements of the invention that directly serve to guide moist air, but also parts of neighboring machines on which condensation could form.Purely as an example, conveyor chains for conveying the target material or similar can be mentioned.

[0031] As an alternative to measuring a base temperature, which serves as the basis for determining the reference temperature for setting the inflow temperature, such a base temperature can also be estimated and manually specified. It is also conceivable that it be taken from other sources and, if necessary, communicated electronically. Thus, it can be expedient if the independently set preset temperature for room air conditioning is communicated as a base temperature to the device according to the invention, whose control unit then determines the reference temperature for specifying the inflow temperature.

[0032] The condensate produced during the cooling of the moist air coming from the evaporator, i.e., during the reduction of its absolute moisture content in the cold trap, can be discharged as wastewater. Alternatively, it can be fed into an existing cooling water system. Preferably, the moisture precipitated in the cold trap, i.e., the condensate produced there, is returned to the water bath. The water can then be used to generate new moist air.

[0033] Particularly - but not only - in systems with this type of water recycling, it appears advantageous if the moist air and / or the water used to generate it is treated with antibacterial and / or fungicidal agents in the moist air generation device. In the context of the device according to the invention, this means that the moist air generation device is set up to treat the moist air and / or the water bath with antibacterial and / or fungicidal agents. For example, the moist air generation device can comprise a chemical dosing device that specifically adds antibacterial and / or fungicidal agents to the water bath. These are preferably substances that are evaporated together with the water, so that elements exposed to the resulting moist air are also protected against fungal and / or bacterial infestation. Such a safety measure is particularly recommended when operating the device according to the invention in a warm, humid environment, such as, for example, in a kitchen.in countries with subtropical or tropical climates.

[0034] The humid air supply system and the piping components used in its construction, such as hoses and / or pipes, are particularly susceptible to fungal and / or bacterial contamination. To enable early detection of such contamination, a further development of the invention provides for said piping components to be made of an optically transparent material. Early detection of contamination allows for timely cleaning or replacement of such components.

[0035] Further details and advantages of the invention will become apparent from the following specific description and drawings. Brief description of the drawings

[0036] It shows: Figure 1: a highly schematic representation of an embodiment of a cold glue application device according to the invention. Description of preferred embodiments

[0037] Figure 1shows, in a highly schematic representation, an embodiment of a cold glue application device 10 suitable for carrying out the method according to the invention. The component thereof serving for the actual glue application, the specific design of which is not relevant in the context of the present invention, is symbolically represented by the application nozzle 12, which is connected to a glue reservoir 16 via a glue line 14. By means of the application nozzle 12, cold glue can be applied from the glue reservoir 16 to a target material (not shown) in the transfer area (below the application nozzle 12).

[0038] To prevent the cold glue from drying on the application nozzle 12, moist inlet air 18' is blown around it. A moist air generating device 20 is used to generate the inlet air 18'. The moist air generating device 20 comprises an evaporator 22, which is designed as an ultrasonic evaporator. For this purpose, the evaporator 22 comprises a water bath 24, which is operatively connected to an ultrasonic transmitter 26. The ultrasonic transmitter 26 generates high-frequency vibrations in the water bath 24, which ensure that small water droplets are propelled into the evaporation chamber 28 located above the level of the water bath 24, where they are absorbed by supply air 32 transported via an intake pipe 30 and evaporated. The supply air 32 is thereby converted into moist air 18 which is completely or at least almost completely saturated with moisture, ie has a relative humidity of approximately 100%.In order to generate the moist air 18 at a temperature that is as close as possible to the target temperature that leads to the desired inflow temperature being reached in the area of ​​the application nozzle 12, in the embodiment shown, both the supply air 32 and the water bath 24 are cooled with appropriate coolants, namely with a supply air cooler 36' and a water bath cooler 36". In the embodiment shown, the moist air 18 generated is passed through a cold trap 34, in which it is cooled by means of a cooler 36, which can be designed, for example, as a Peltier element. The moisture that precipitates in the process, i.e., the condensate that accumulates, is collected in a collection tank 38. In the embodiment shown, the collection tank 38 is connected to the water bath 24 via a return line 40, so that the condensate that accumulates in the collection tank 38 can be fed back to the evaporator 22.The cooled, saturated moist air 18' is thus available at the outlet of the cold trap 34. This is then fed to the application nozzle 12 via a moist air supply device 35, which in the embodiment shown is designed as a hose, and the moist air, which here acts as inflow air 18', flows against the application nozzle.

[0039] The cold glue application device 10 shown further comprises a control device 42, which is connected to the cold trap 34 and the coolers 36', 36" via control lines 44 and is able to control their operation, in particular the extent of cooling there. Furthermore, a temperature measuring device is provided, which in the illustrated embodiment has a plurality of temperature sensors 46. In particular, temperature sensors 46 are provided for detecting the nozzle temperature of the application nozzle 12 and for detecting the moist air temperature at the outlet of the cold trap 34. The control device 42 is set up to adjust the moist air temperature at the outlet of the cold trap 34, ie essentially the inflow temperature at which the application nozzle 12 is flowed, to a predetermined temperature difference above the dew point temperature of the inflow air 18', which in turn is below a predetermined reference temperature, e.g.the nozzle temperature of the application nozzle 12 should be selected. The dew point temperature should be only slightly below the reference temperature, but with a "safety margin" that prevents system malfunctions, especially condensation formation at the application nozzle 12, even in the event of sudden changes in operating parameters. A temperature difference of 1.5 to 2°C has proven to be practical. This ensures, on the one hand, that the application nozzle 12 is surrounded by (almost) saturated, moist air, which prevents cold glue from drying out; on the other hand, the temperature difference prevents condensation from forming on the (warmer) application nozzle.By constantly measuring the nozzle temperature and adjusting the wet air temperature accordingly, this balance is maintained even during long periods of operation and idle time of the system, even if significant temperature fluctuations occur due to the time of day or operating conditions.

[0040] In the illustrated embodiment, additional temperature sensors 46 are provided, in particular one for monitoring the temperature in the evaporator 28, i.e., the moist air temperature at the inlet of the cold trap 34, and one on a wall 48, only symbolically indicated, which is intended to generally represent the peripheral surfaces previously mentioned in the general part of the description. The latter, in particular, allows the reference temperature to be selected such that any condensation is prevented or at least significantly reduced, not only on the application nozzle 12, but also on the surrounding room walls (including the floor) and machine surfaces.

[0041] As a special feature, the illustrated embodiment also has a chemical dosing device 50, from which the water bath 24 can be inoculated with antibacterial and / or fungicidal substances in order to prevent the spread of corresponding germs with the moist air.

[0042] Of course, the embodiments discussed in the specific description and shown in the figures represent only illustrative embodiments of the present invention. In light of the disclosure herein, a broad spectrum of possible variations is available to the skilled person. In particular, the choice of the reference temperature can be quite complex and involve several different measurement results, whereby it is always up to the skilled person in each individual case to demonstrate a suitable compromise between keeping the glue moist and avoiding condensation, taking into account the respective site characteristics. Cooling of the moist air can also be achieved without using all three coolers 36, 36', 36" shown. It is also possible to achieve the same result with just one or any combination of the coolers 36, 36', 36" - in particular, even without the cold trap 34 or exclusively using the cold trap 34. List of reference symbols

[0043] 10Cold glue application device 12Application nozzle 14Glue line 16Glue reservoir 18Moist air 18Inlet air 20Moist air generation device 22Evaporator 24Water bath 26Ultrasonic generator 28Evaporation chamber 30Intake pipe 32Inlet air 34Cold trap 35Moist air supply device 36Trap cooler 36Inlet air cooler 36Water bath cooler 38Collection tank 40Return line 42Control device 44Control line 46Temperature sensor 48Wall 50Chemical dosing device

Claims

1. A method of operating a cold glue applicator (10) having application means connected to a glue reservoir (16) by means of which application means cold glue can be applied to a target material, said method comprising the steps of: - generating moist air (18) by means of a moist air generating device (20), and - feeding the generated moist air (18) as inflow air (18') to the application means, which are thus flowed against externally by the inflow air (18'), wherein an inflow temperature, namely the temperature of the inflow air (18'), is set to a temperature value above the dew point temperature of the inflow air (18') by means of a temperature adjusting device, characterized in that the moist air generating device (20) comprises an ultrasonic evaporator (22), namely an open water bath (24) which is set into high-frequency oscillation during operation by means of an ultrasonic transducer, whereby water is propelled out of the surface layer of the water bath in very small droplets and is evaporated very quickly in the air supplied, i.e. in the supply air, due to the large surface area of the droplets relative to their volume, and the temperature adjusting device has a water bath cooler (36"), by means of which a water bath (24) is cooled in such a way that a generation temperature, namely the temperature at which the moist air (18) is generated, is set such that the inflow air (18') has the inflow temperature.

2. A method of operating a cold glue applicator (10) having application means connected to a glue reservoir (16) by means of which application means cold glue can be applied to a target material, said method comprising the steps of: - generating moist air (18) by means of a moist air generating device (20), and - feeding the generated moist air (18) as inflow air (18') to the application means, which are thus flowed against externally by the inflow air (18'), wherein an inflow temperature, namely the temperature of the inflow air (18'), is set to a temperature value above the dew point temperature of the inflow air (18') by means of a temperature adjusting device, characterized in that the moist air generating device (20) comprises an ultrasonic evaporator (22), namely an open water bath (24) which is set into high-frequency oscillation during operation by means of an ultrasonic transducer, whereby water is propelled out of the surface layer of the water bath in very small droplets and is evaporated very quickly in the air supplied, i.e. in the supply air, due to the large surface area of the droplets relative to their volume, and the temperature adjusting device has a cold trap (34) through which the moist air (18) passes before it is fed to the application means and in which the moist air (18) is cooled to a target temperature which is dimensioned such that the inflow air (18') has the inflow temperature.

3. A method of operating a cold glue applicator (10) having application means connected to a glue reservoir (16) by means of which application means cold glue can be applied to a target material, said method comprising the steps of: - generating moist air (18) by means of a moist air generating device (20), and - feeding the generated moist air (18) as inflow air (18') to the application means, which are thus flowed against externally by the inflow air (18'), wherein an inflow temperature, namely the temperature of the inflow air (18'), is set to a temperature value above the dew point temperature of the inflow air (18') by means of a temperature adjusting device, characterized in that the moist air generating device (20) comprises an ultrasonic evaporator (22), namely an open water bath (24) which is set into high-frequency oscillation during operation by means of an ultrasonic transducer, whereby water is propelled out of the surface layer of the water bath in very small droplets and is evaporated very quickly in the air supplied, i.e. in the supply air, due to the large surface area of the droplets relative to their volume, and the temperature adjusting device has a supply air cooler (36'), by means of which the supply air (32) is cooled in such a way that a generation temperature, namely the temperature at which the moist air (18) is generated, is set in such a way that the inflow air (18') has the inflow temperature.

4. Method according to one of the preceding claims, characterized in that a setting specification for the inflow temperature is continuously determined on the basis of repeated temperature measurements and the temperature adjusting device is actuated for a correspondingly tracking adjustment of the inflow temperature.

5. Method according to claim 4, characterized in that a nozzle temperature of an application nozzle (12), an air temperature of a room air at the installation site of the cold glue applicator (10), a wall temperature and / or floor temperature of room boundaries at the installation site of the cold glue applicator (10) and / or a temperature of peripheral machine parts are determined by means of the temperature measurements.

6. Method according to one of claims 1 to 3, characterized in that the inflow temperature is fixed.

7. Method according to claim 2 or one of claims 4 to 6, insofar as related back to claim 2, characterized in that moisture precipitating in the cold trap (34) is returned to the water bath.

8. Method according to claim 2 or one of claims 4 to 6, insofar as related back to claim 2, characterized in that the moisture precipitating in the cold trap (34) is discharged as waste water and / or as cooling water.

9. Method according to one of the preceding claims, characterized in that the moist air (18) and / or a water bath in the moist air generating device (20) is treated antibacterially and / or fungicidally.

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