AIR-FLOW APPARATUS

The present disclosure relates to an air-flow apparatus for treating air and drying an object, in particular a human hand, which is, for example, contaminated with germs.

The present application is supported by the Österreichische Forschungsförderungsgesellschaft mbH, FFG number 885038.

Conventional drying devices use blowers for hand drying, for example, which contribute to the distribution of germs into the room air and the environment of the dryer. Germs distributed in this way can then be further transmitted through the air or by smear infection.

Examples include conventional hand dryers that blow air at the highest possible velocity onto hands or other objects to be dried. For example, a conventional hand dryer comprises a housing, an opening in the housing for introducing objects to be dried, and a blower or positive pressure pump for generating a stream of air that is applied via a nozzle to the object to be dried, such as a hand.

A disadvantage of such methods is the use of the air-flow generated by a blower or positive pressure pump to blow the water droplets and aerosols still contaminated with germs off the hands to be dried, but at the same time distributing them in the room air and to all objects in the room.

With pathogens such as influenza viruses, COVID-19 pathogens or multi-resistant germs that can be transmitted via respiratory or smear infection, this type of hand drying can lead to a significantly higher risk of infection in the washroom due to accumulation of the germs. For this reason, hospitals have increasingly returned to using the classic method of hand drying with disposable paper towels.

From EP 2656762 A2 a combined blower and exhaust method is known which tries to address this problem of contamination of the ambient air at least partially. EP 2656762 A2 uses a fan with subsequent air cleaning at the bottom of a chamber that is open at the top, and returns the exhaust air to the area of the opening via pipes in the side walls. The air then exits through a nozzle at high velocity.

An object to be achieved is to provide an improved concept suitable for both air cleaning and object drying, which reduces or overcomes the disadvantages associated with conventional drying methods.

This object is achieved by the subject-matter of the independent patent claim. Further embodiments and embodiments can be found in the dependent claims.

The improved concept is based on the idea that an air-flow apparatus achieves a suction effect instead of blowing air by generating an air flow directed inwardly, i.e. into an interior space of a housing, by means of an underpressure or suction pump.

The inwardly directed air flow causes liquid particles, in particular liquid particles contaminated with germs, to be sucked into the interior and to be discharged in a protected manner via an outlet of the pump. A blowing of liquid particles contaminated with germs into the environment of the air-flow apparatus can thus be reliably prevented.

The improved concept is further based on the idea that, in addition to the suction pump, a flow arrangement with a controllable overpressure generation device is provided, which is connected to the interior space on its outlet side via at least one nozzle. This generates a second air flow directed into the interior space for drying the object. This makes it possible, for example, for the air-flow apparatus to be used, on the one hand, for purely drying an object, in which the first and second air flows prevent air contaminated with germs from escaping from the interior space. In addition, the air-flow apparatus can also be used for purely extracting air from the environment, in which case the overpressure generation device can remain deactivated. Thus, ambient air contaminated with germs can be purified.

In one embodiment of the improved concept, an air-flow apparatus is adapted to treat air and to dry an object, for example a human hand. In this case, the air-flow apparatus comprises a housing with an interior space, into which the object to be dried can be introduced via an opening of a partially opened lid of the housing, and with a bottom opposite the lid. A pump is connected on its inlet side to the interior space in such a way that, by means of a pumping action of the pump, a negative pressure is generated in the interior space and a first air flow directed from the opening into the interior space, for example exclusively into the interior space, is generated for drying the object. In this regard, the pump is configured to discharge, on its outlet side, an outlet air flow passing through the pump.

The air-flow apparatus further comprises a flow arrangement having a controllable overpressure generating device, an inflow pipe and at least one nozzle. The overpressure generating device is connected on its outlet side via the inflow pipe and the at least one nozzle to the interior space and is adapted to form an overpressure in the inflow pipe and to generate via the at least one nozzle a second air flow directed into the interior space for drying the object.

The pump is designed, for example, as a suction pump, in particular as a vacuum pump, and is connected to the interior, for example, on its inlet side via corresponding pressure lines. The pump is connected to the interior space via the base, for example, in order to maximize a suction effect with respect to the opening and thereby optimize the air flow.

For example, the opening of the lid is shaped such that a flow cross-sectional area formed in the opening between the object and the lid, for example an inner edge of the opening in the lid, is minimized. The opening of the lid is thus adapted as well as possible to the usual shape of the object to be dried, for example the human hand or hands. By reducing the flow cross-sectional area at the opening, the efficiency of the air flow is improved.

For example, in this case, the opening of the lid is shaped in such a way that the air flow in the area of the lid reaches a maximum velocity according to the principle of a nozzle at a given suction power of the pump.

The lid of the housing, in particular the opening in the lid, can have a fixed, unchanging shape. Thus, for example, the opening is suitable for different sizes and shapes of the objects to be dried, for example, hands.

In the case that the opening is chosen to be so small for increasing the flow velocity of the first air stream that contact between the object to be dried and the air-flow apparatus cannot be excluded, additional cleaning devices can be provided which are automatically activated by means of one or more sensors after removal of the object to be dried.

However, the opening can also be dimensioned in such a way that when the object to be dried is inserted and removed, the opening is sufficiently large to prevent unintentional contact with the lid or the interior space and thus prevent smear infections.

For example, a unit for removing and/or decontaminating the output air flow, such as the output air flow contaminated with germs, is attached to an outlet tube of the pump. In various embodiments, the overpressure generating device is formed by another pump. Alternatively, the overpressure generation device is formed by an electrically controllable valve, which is connected on the input side to an output of the unit for decontamination. In this case, the pressure generation is effected by the pump, which thus generates a negative pressure on the input side and a positive pressure on the output side via the air-flow apparatus.

In various embodiments, the air-flow apparatus further comprises a control element electrically connected to the pump and the overpressure generating device for controlling modes of operation of the air-flow apparatus. In this regard, the control element is adapted, in a drying mode, to activate the pump and the overpressure generating device to generate the first and second airflows. The control element is further adapted, in an air purification mode, to activate the pump and deactivate the overpressure generating device to generate the first airflow and not generate the second airflow.

Switching between the operating modes can be done manually. Alternatively or additionally, however, the operating modes may be selected by sensor control.

For example, the air-flow apparatus further comprises at least one detection sensor that is adapted to detect an object in the interior space. In this case, the control element is adapted to activate the drying mode when the object in the interior space is detected and to deactivate the drying mode when the object in the interior space is not detected or when detection of the object in the interior space has terminated. The deactivation can also be time-dependent, for example, so that the drying mode is only terminated a predetermined time after removal of the object from the interior space and corresponding detection of this state.

The at least one sensor may, for example, be implemented as a distance sensor, for example as a RADAR sensor or a high-frequency sensor or a LIDAR sensor or other optical sensor.

In various embodiments, the at least one sensor is configured to detect a type of object and/or a size of the object and/or a position of the object in the interior space. This information can also be used, in each case, to control the pump and/or to change the opening of the lid, to the extent that it is controllable.

In some embodiments, the air-flow apparatus further comprises at least one sensor for germ detection and/or measurement of the air quality or various parameters of the air quality, which is mounted on an outside of the housing or in an exterior space or outside the interior space, respectively, and is set up in each case to detect the germ load or air quality of air in the exterior space. The control element is adapted to activate the air cleaning mode if an exceeding of a predetermined threshold value of the germ load of the air in the exterior space is detected by means of the at least one sensor for germ detection or measurement of the air quality. The activation of the air cleaning mode can, for example, be made dependent on whether the drying of an object is currently being carried out, i.e. the drying mode is activated. For example, the air purification mode is only activated when the air-flow apparatus is in a standby mode in which neither the pump nor the overpressure generation device are activated.

Thus, the air-flow apparatus can be controlled in such a way that, for example, when the lid is open, e.g., when the lid is open to the maximum extent, it is basically operated in continuous mode as an air cleaner, and only switches to drying operation mode when one or more sensors detect hands to be cleaned or dried. By means of one or more sensors additionally installed in the outer casing of the apparatus or in the room for measuring the germ load of the breathing air or ambient air, the air cleaning mode of the apparatus can thereby be controlled in such a way that the pump is switched on only when a critical threshold value of the room air load is exceeded. In the case of sensors installed separately from the air-flow apparatus in the room for determining the germ load, radio modules are provided in the sensors and in the air-flow apparatus, respectively, for transmitting and receiving the sensor data. In case of detection of falling below the threshold value, the pump is deactivated.

Such sensors for measuring the germ load can either be biological sensors for measuring typical germs such as viruses or bacteria, or—similar to an air conditioning system—simple air quality sensors, which, for example, detect the CO2 content of used breathing air and assume a corresponding correlation with the germ load caused by humans, e.g. multi-gas sensors for Volatile Organic Compounds, VoC, or CO2 sensors. Other sensors for complete detection of indoor air quality, such as for radon, CO, NOx, relative humidity, formaldehyde, etc., may also be optionally integrated on or in the air-flow apparatus.

The air-flow apparatus may further include a display or screen for displaying the germ load and/or air quality data measured by the sensors, so that the air-flow apparatus also integrates, for example, the function of an air quality monitoring device for the outside space. Alternatively or additionally, the data obtained by the air-flow apparatus, in particular air quality data, can also be transmitted to other devices, such as smartphones or smartwatches, of the users of the air-flow apparatus.

In various embodiments, the air-flow apparatus comprises at least one pressure sensor in the interior space and/or on an exterior side of the housing and/or in an exterior space. In this regard, the control element is arranged to control the pump and/or the overpressure generating device based on pressure values recorded with the at least one pressure sensor. In addition, other sensors such as air flow sensors or humidity sensors may be mounted in the interior of the air-flow apparatus for pump control.

In various embodiments, a valve is attached to an outlet tube of the pump to prevent backflow of airflow, such as air-flow contaminated with moisture particles and germs. This can prevent particles contained in the air flow from flowing back into the pump and back over it into the interior of the air-flow apparatus, for example, when the pump is switched off.

In further embodiments, a unit for discharging and/or decontaminating the air flow, in particular the air flow contaminated with germs, is attached to such an outlet pipe of the pump. Such a unit prevents, for example, germs from re-entering a surrounding area of the air-flow apparatus and possibly infecting people there, as is possible with conventional drying devices. Alternatively or additionally, such a unit can also be attached to an inlet pipe of the pump, for example between the interior or the base and the pump.

Such a unit may be, for example, a simple drain pipe connected to a sewer or the like, a UV disinfection unit with or without connection to such a drain pipe, a container partially filled with disinfectant which is replaceable or connected to a drain pipe, a combination of several filter stages (particle filter, HEPA filter, UV filter, ion filter, . . . ) as used in typical air purification equipment, or another suitable disinfection equipment with waste water tank for collecting the humid air mixture, possibly contaminated, or with connection to a drain pipe.

In the event that the unit for decontamination of the air flow effectively kills the germs and filters the air accordingly, the discharge pipe can be omitted if the condensed liquid particles are also collected in a container connected to the filter unit. The air cleaned in this way can then be returned to the room via outlet openings. This is particularly advantageous if the ambient air is appropriately contaminated with germs and the air-flow apparatus is also provided with an additional continuous operation mode for purifying the ambient air.

In various embodiments, the air-flow apparatus further comprises at least one injector mounted above the lid for introducing disinfectant onto the lid and into the first air flow. In this regard, the control element is configured, for example, to activate the injector and the pump to generate the first air flow in a self-cleaning mode. In this way, germs located in the air flow can be treated immediately. At the same time, the object to be dried can also be disinfected. Furthermore, the air-flow apparatus itself can be cleaned in this way.

For example, the injector is mounted above the lid in such a way that the lid can be cleaned by the disinfectant either in-situ or by programming after the end of a drying process. Thus, for example, smear infections can be reduced or prevented if, for example, the object contaminated with germs touches the lid. In the embodiments described, several suction zones of the pump can be provided in the bottom and/or on side walls of the interior. This allows, for example, the air flow to be shaped in a more targeted manner.

In the various embodiments of the air-flow apparatus, the first air flow is preferably greater than the second air flow. In other words, the negative pressure in the interior space generated by the pump is accordingly greater in amount than a positive pressure in the interior space generated by the positive pressure generating device. This ensures that even when the positive pressure generation device is activated, air is safely extracted from the first and second air streams and no air contaminated with germs can escape through the opening of the lid.

If the overpressure generation device is formed by a further pump, the air-flow apparatus comprises, for example, a filter system for cleaning ambient air which is drawn in by the further pump via an inlet. In this way, it can be ensured that no air contaminated with germs is blown into the interior via the flow arrangement.

Alternatively, the further pump can be connected on the inlet side via a valve to an outlet of the unit for decontamination. This again ensures that the air transported by the additional pump is not contaminated with germs. For example, the unit for decontamination has an inlet for the supply of ambient air. This makes it possible to achieve improved control of the air flows. The supply of ambient air can be controlled, for example by an electrically controllable valve.

As already mentioned, in alternative embodiments the overpressure generating device can also be formed by an electrically controllable valve, which is connected on the input side to an output of the system for decontamination. In this case, the controllability is provided, for example, by the ability to open and close and/or regulate the air flow.

In the embodiments described, a plurality of suction zones of the pump may be provided in the floor and/or on side walls of the interior space. This allows, for example, the air flow to be shaped in a more targeted manner.

For example, the suction zones can be controlled independently to regulate the air flow for optimal positioning of the object to be dried. For example, an independently controllable valve is attached to at least one, in particular each, of the suction zones for this purpose. A combination of permanently open suction zones and controllable suction zones, for example with a valve, can advantageously be considered.

In various embodiments, the floor has one or more perforations through which the air flow from the interior space is directed to the pump. Such perforations in the floor also represent, in a sense, suction zones.

In various embodiments, the air-flow apparatus has one or more additional suction lines directed into the interior space and connected to the pump or vacuum pump, which are arranged near the partially opened lid and connect the pump to the interior space. In particular, suction zones of these suction lines are arranged near the partially opened lid. The at least one suction line opens, for example, near the partially opened lid into the interior space in such a way that an air flow parallel or substantially parallel to the lid is generated, which acts, for example, as an “air flow lid” or “air lid” for short. With this method, the mechanical lid can have a comparatively large opening to allow objects to be dried to be conveniently inserted or removed without touching the air-flow apparatus, while at the same time ensuring that at all times the escape of germs from the interior space is prevented as much as possible or even completely.

Instead of a single pump in each case, a plurality of pumps can also be used, which are connected in parallel with respect to different suction zones, for example. Instead of or in addition to the valves, the individual pumps can also be controlled separately.

The improved concept is explained in more detail below by means of embodiment examples with reference to the drawings. Here, similar elements or elements with the same functions are designated with the same reference signs. Therefore, a repeated explanation of individual elements is omitted where appropriate.

In the drawings:

FIGS. 1A to 1C show various views of one embodiment of an air-flow apparatus,

FIGS. 2A to 2C show various views of a further embodiment of an air-flow apparatus,

FIGS. 3A and 3B show various views of a further embodiment of an air-flow apparatus,

FIGS. 4A and 4B show different views of a further embodiment of an air-flow apparatus,

FIG. 5 shows an example of an embodiment of an air-flow apparatus,

FIGS. 6A and 6B show different views of a further embodiment of an air-flow apparatus,

FIGS. 7A and 7B show different views of a further embodiment of an air-flow apparatus,

FIGS. 8A to 8C show various views of further embodiments of an air-flow apparatus,

FIGS. 9 to 13 show various views of further embodiments of an air-flow apparatus,

FIGS. 14A and 14B show various views of a further embodiment of an air-flow apparatus,

FIG. 15 shows a view of a further embodiment of an air-flow apparatus, and

FIGS. 16A and 16B show various views of a further embodiment of an air-flow apparatus.

In the following, various embodiments of an air-flow apparatus are described which illuminate individual aspects of the invention. Although individual figures show only partial aspects of the invention as defined in the claims, these aspects may each be combined with other aspects unless this is expressly excluded.

FIG. 1A shows a sectional view of an exemplary embodiment of an air-flow apparatus. The air-flow apparatus comprises a housing 11 in which an interior space 11′ is formed and which has a lid 12 at its upper end, which lid 12 is partially open. Through the opening of the lid 12, an object 6 to be dried can be inserted, which in this example represents a human hand. The air-flow apparatus further comprises a pump 15, which is connected to the interior space 11′ on the inlet side. The pump 15 is designed, for example, as a vacuum pump or suction pump, so that during operation of the pump 15 an air flow 7 is generated which is directed from the opening in the lid 12 into the interior space 11′ for drying the object 6. A negative pressure is thus generated in the interior space 11′ by the pump 15.

A base 13 is provided in the interior 11′, which is opposite the lid 12 and contains perforations 14 through which the air stream 7 is directed as an outlet air stream 9 from the interior 11′ to the pump 15 via an or intake pipe an inlet pipe 15′. On its outlet side, the pump 15 is connected via an outlet pipe 15″ to a schematically shown unit 17 for collecting moisture particles 7′. The unit 17 can, for example, be connected to the pump via an optional valve 16 in order to prevent the outlet air flow 9 from flowing back into the pump. The liquid particles or moisture particles 7′ may be contaminated with germs during operation, which are extracted from the object 6 to be dried.

FIGS. 1B and 1C show the air-flow apparatus in a top view, whereby in FIG. 1B the opening in the lid 12 as well as the base 13 with the perforations 14 can be clearly seen. In FIG. 1C, the objects 6 to be dried are additionally shown in a cross-sectional view, for example in the area of the wrists. Here, a certain distance 6′ of the objects 6 to be dried to the edge of the opening of the lid 12 results. In the present embodiment example, this distance 6′ results in a flow cross-sectional area which essentially corresponds to the size of the opening of the lid 12.

With reference back to FIG. 1A, one or more sensors 21 may be provided in the interior space 11′, which are arranged, inter alia, to detect an object 6 in the interior space 11′. In addition, the air-flow apparatus may include a control element 23, for example on an electrical circuit board, which is electrically connected to the sensor or sensors 21 and to the pump 15. Thus, the control element 23 can, for example, activate or deactivate the pump depending on a detection of an object to be dried in the interior space 11′.

The at least one sensor 21 is, for example, a distance sensor, such as a high frequency RADAR sensor or LIDAR sensor or other optical sensor suitable for detection. A drying process can thus be started by automatically switching on the pump as soon as the insertion of the object or objects to be dried, for example hands, is detected by the at least one sensor 21.

As can be seen from FIG. 1A, the suction principle means that any liquid particles or moisture particles 7′ which may be contaminated with germs are removed from or kept away from the outer chamber 8 by the air flow 7 which, in contrast to conventional air-flow apparatuses, is directed only into the interior of the housing 11. The air flow 7 generated for drying flows off by action of the suction pump or vacuum pump through the base 13 provided with perforations 14 via the suction pipe 15′ through the pump 15, the outlet pipe 15″ and the valve 16 into the unit 17 for discharging the outlet air flow 9 contaminated with germs. As mentioned, the valve 16 serves, for example, to prevent the backflow of a germ-laden, moist air mixture. The unit 17 thus prevents germs from re-entering the surrounding area 8, where they could potentially infect people.

Such a unit 17 may be, for example, a simple drain pipe, a UV disinfection unit (with or without connection to the drain pipe), a container partially filled with disinfectant (either periodically replaced or connected to the drain pipe), or any other suitable disinfection unit with a waste water tank to collect the germy humid air mixture or with connection to the drain pipe.

In the event that the unit for decontamination of the air flow effectively kills the germs and filters the air accordingly, the discharge pipe can be omitted if the condensed liquid particles are also collected in a container connected to the filter unit. The air thus purified can then be returned to the room through outlet openings. This is particularly convenient if the ambient air is appropriately contaminated with germs and the air-flow apparatus is also provided with an additional continuous operation mode for cleaning the ambient air.

From FIGS. 1B and 1C, it can likewise be seen that the distance 6′ between the object 6 and the inner edge of the lid 12 determines the effective flow cross-section and, for a given suction power of the pump, also the flow velocity of the air flow 7 as it enters the air-flow apparatus through the lid 12. The higher the flow velocity, the better the cleaning effect.

With reference to FIG. 2A, the opening in the lid 12 can also be limited in size by suitable shaping of the lid in order to minimize the required suction power of the pump or to maximize the efficiency. The distance 6′ is thereby reduced compared to FIG. 1A. This can also be clearly seen in FIGS. 2B and 2C.

It should also be noted that the opening should still be large enough to prevent the object 6 to be cleaned (e.g. hands) from coming into contact with the edges of the lid 12, so as to also minimize the risk of smear infections via contamination of the hands to be dried.

FIG. 3A and FIG. 3B show a possible further development based on the embodiments of the figures described above.

In FIG. 3A, an optional device 19 for injecting disinfectant into the air flow 7 is located in the area above the lid 12. Additionally shown are particles 20 of the disinfectant. This achieves in-situ disinfection of the lid 12 and also disinfection of the air flow 7, so that, for example, a simple drain pipe or UV disinfection system can suffice as a unit 17. By special programming, after the end of a cleaning cycle or drying process for the objects 6, i.e. when the objects 6 have been removed from the interior space 11′ again, the lid 12 can be cleaned by the device 19 for disinfection and an air flow 7 generated by the pump 15, so that it is ready for the subsequent user.

In FIGS. 3A and 3B, one can also see an adaptive lid 12 with one (or more) movable elements 18 for minimizing the distance 6′ and thus the flow cross-section for the air flow 7 in the area of the lid 12. During the insertion of the objects 6, the lid can be or be automatically opened further, and as soon as the sensors 21 detect that the objects 6, e.g. the hands, have been positioned in the interior space 11′, the lid 12 would close accordingly by controlling the movable element 18 so far that the flow cross-section is minimized.

FIG. 4A and FIG. 4B show a possible further development based on the embodiments of FIGS. 3A and 3B. In contrast, here at least two movable elements 18 form the lid, which are shaped in such a way that the distance 6′ and thus the flow cross-section around the objects 6 (hands) is minimized.

A lid 12 with one or more movable elements can also be used in the embodiments of FIGS. 1A to 1C and FIGS. 2A to 2C, independently of the disinfection device 19.

In addition, the air-flow apparatus can still be provided with separate suction zones, which can optionally also be controlled separately, for example with perforations 14 on the side walls and in the floor 13 of the interior space 11′. Independent control of the suction zones can be implemented with separate pumps 15 in each case, or alternatively with valves 24, such as shown by way of example in FIG. 5.

The pumps and/or valves can also be controlled on the basis of signals from the sensors 21 via the control element 23. The aim of using multiple suction zones is to control the air flow 7 even more precisely, thus enabling the optimum positioning of the objects 6 during the drying process.

To further increase effectiveness, the suction zones can also be additionally equipped with rapidly heatable heating elements, e.g. infrared lamps. However, it must be ensured that no excessive temperature gradients are created in the interior space 11′ in order to avoid disturbing the vertically downward air flow 7.

In the event that the air surrounding the air-flow apparatus is also already very heavily contaminated with germs, this problem can initially be solved by introducing dermatologically safe cleaning agent into the air flow 7 by means of one or more injectors 19, whereby in-situ sterilization takes place in the air flow.

As an additional or also alternative measure, as shown in FIG. 6A and FIG. 6B, the air-flow apparatus can be controlled in such a way that, for example, with the lid 12 open to the maximum extent, it is operated with optional movable elements 18 basically in continuous operation as an air cleaner, and only switches to drying operation mode, as shown in the preceding figures, when objects 6 such as hands to be cleaned or dried are detected by one or more sensors 21.

By means of one or more additional sensors 25 mounted in the outer shell of the apparatus or in the room for measuring the germ load of the breathing air, the air-cleaning mode of the apparatus can thereby be controlled so that it is switched on only when a critical threshold value of the room air load is exceeded, e.g. by activating the pump 15. In the case of sensors for determining the germ load mounted separately from the air-flow apparatus in the room, radio modules are provided in the sensors and in the air-flow apparatus, respectively, for transmitting and receiving the sensor data. Such sensors for measuring the germ load can be either biological sensors for measuring typical germs such as viruses or bacteria, or—similar to an air conditioning system—simple air quality sensors that detect the CO2 content of consumed breathing air and assume a corresponding correlation with the germ load caused by humans, e.g. multi-gas sensors for Volatile Organic Compounds, VoC, or CO2 sensors. Other sensors for complete detection of indoor air quality, such as for radon, CO, NOx, relative humidity, formaldehyde, etc., may also be optionally integrated on or in the air-flow apparatus.

In another embodiment, shown in FIGS. 7A and 7B, the interior space 11′ can be designed by means of a nozzle-shaped insert 26 instead of the lid 12 in such a way that the flow cross-section 6′ shown in FIG. 7B initially decreases with increasing depth and only increases again at depth in the direction of the base 13. This nozzle shape also achieves a corresponding reduction in the flow cross-section and thus an increase in the flow velocity to shorten the drying time.

However, in order to achieve flow velocities of 50 to 100 m/s in the narrowest range, for example, the normal distance 6′ between the hands 6 to be dried and the insert 26 should be reduced to well below 10 mm. In practice, however, this requires cleaning by means of an injector 19 because the occasional contact of the hands 6 to be cleaned with the side walls of the insert 26 during the cleaning process can hardly be avoided. Similarly, the nozzle-shaped insert may also be designed with movable elements to allow even better adaptation to hands 6 of different sizes (not shown).

In the illustrations of FIGS. 8A and 8B and 9 to 13, the principle described so far is supplemented in accordance with the improved concept of the present application in that, in addition to the pump 15, a flow arrangement is provided which has a controllable overpressure generation device 27 or 44 which is connected on the outlet side to the interior space 11′ via an inflow pipe 28 and at least one nozzle 29. The overpressure generating device is thereby adapted to form a positive pressure in the inflow pipe 28. While the pump 15 causes a negative pressure in the interior space 11′ and thus a first air flow 7 by means of its pumping action, a second air flow 30 directed into the interior space 11′ is generated by the positive pressure in the inflow pipe 28 via the at least one nozzle 29, which air flow contributes to drying the object 6.

Thus, a global negative pressure can be generated in the air-flow apparatus via the pump, which can be used for manual cleaning as well as for air cleaning of the air from the environment 8. In addition, a local overpressure is generated, especially at the outlet of the nozzle 29, which enhances the local drying effect on the object 6. This increases the efficiency of cleaning the object, for example the human hand. The first and second air flows provide an independent control possibility of the maximum air flow speed at the surface of the hands in order to maximize the drying effect, in particular without having to make the distance 6′ between the walls of the interior space 11′ and the hands to be dried particularly narrow.

With reference to FIG. 8A, the overpressure generating device is formed there by a further pump 27 which draws in air from the environment 8 via an opening 31 and a subsequent filter 32.

The pump 27 compresses the air to generate an overpressure Opt which results in the second air flow dV₂/dt 30 via the piping system 28 and the nozzle(s) 29. The vacuum pump(s) 15 and overpressure pump(s) 27 are preferably always dimensioned and controlled in such a way that a resulting negative pressure is created in the interior space 11′ in order to avoid contamination of the environment 8 by drying the hands 6. Therefore, for the resulting pressure change Δp in the interior space 11′ caused by the action of the vacuum pump 15, which generates a negative pressure Δp₁, and the action of the overpressure pump 27, which generates the overpressure Δp₂, always Δp<0. I.e. further Δp₁+Δp₂<0 where Δp₁<0 (negative pressure) and Δp₂>0 (positive pressure). Thus, |Δp₁|>|Δp₂| holds. I.e. further, a negative pressure prevails in the interior space 11′ during the drying process compared to the pressure p in the environment 8.

Assuming that a steady-state flow is quickly established after switching on the pumps 15, 27, it can be derived from Bernoulli's equation that the volume flow Q=dV/dt is directly proportional (with the constant c, and a constant density p) to the root of the pressure difference Δp generated by the pumps in the interior space 11′:

$Q = \frac{dV}{dt} = c * \sqrt{(\frac{2}{ρ} * Δ p)}$

In the case of a steady flow, this also means that the amount of the volume flow dV₁/dt generated by the vacuum pump 15 is always greater than the amount of the volume flow dV₂/dt generated by the overpressure pump 27 in order to ensure that a vacuum always prevails in the interior space 11′.

As an example, in FIG. 8A, a vacuum pump 15 with 1400 W power could be selected to generate a volume flow of about 75 liters/s at a vacuum of about 250 mbar. For the overpressure pump 27, for example, a volume flow of about 50 liters/s could be generated at an overpressure of about 150 mbar and a power of up to a maximum of 900 W. With a diameter of the nozzles 29 of less than 1 mm, speeds of the second air flow of more than 80 m/s could then be achieved, which would be more than sufficient for a very good drying effect in a time significantly less than 15 sec.

The air-flow apparatus in FIG. 9 also has sensors 37 for measuring the pressure in the exterior space 8 and sensors 38 for measuring the pressure in the interior space 11′. These are in turn connected to the control element 23 and enable the control element 23 to selectively control the pump 15 and the overpressure generating device designed as a pump 27 based on the corresponding sensor data.

In these embodiments, the control element 23 is also arranged, for example, to control operating modes of the air-flow apparatus. For example, in a drying mode, the control element 23 activates the pump 15 and the positive pressure generating device 27 to generate the first and second air flows. Similarly, in an air purification mode, the control element 23 may activate the pump 15 while deactivating the positive pressure generating device 27 to generate the first air flow 7 and not generate the second air flow 30. Thus, as shown in FIG. 8A, the air-flow apparatus can be used both for drying an object, in particular a human hand 6, and for treating air, in particular in connection with the apparatus 17 for removing the air flow contaminated with germs, as explained in detail above.

For example, the control element 23 will activate the drying mode when an object 6 is detected in the interior space 11′ via the at least one detection sensor 21. Furthermore, if the detection of the object 6 in the interior space 11′ is absent or terminated, the drying mode is deactivated. This can be done, for example, in a time-controlled manner after detection of the object 6 has ended.

Typically, the vacuum pump 15 is started earlier and continues to run after the positive pressure generating device 27 is turned off at the end of the drying process. If the air-flow apparatus is operated as an air cleaner, then the positive pressure generating device 27 remains turned off and only the negative pressure pump 15 is operated.

With reference to FIGS. 8B and 8C, top views of the air-flow apparatus are again shown there. Whereas in FIG. 8B a common interior space is used for two hands, in FIG. 8C the interior space is divided into two interior spaces, each of which, however, is constructed according to the same principle. The nozzles 29 run, for example, in a ring around the hands to be dried. The nozzles 29 can be designed, for example, by means of circular or point-shaped or slot-shaped openings and are shaped, for example, in such a way that the incoming air from the inflow tube 28 is accelerated to the highest possible velocity, for example 50 to 100 m/s, by the outlet opening having the smallest possible diameter, for example smaller than 1 mm. In the case of particularly small diameters, velocities of considerably greater than 100 m/s can also be achieved.

FIG. 9 shows a modification of the air-flow apparatus shown in FIG. 8. Here, instead of a single outlet area of the nozzles 29, several nozzles integrated in the interior wall of the interior space 11′ are provided.

In both FIG. 8A and FIG. 9, the angle of the second air flow 30 exiting the nozzles 29 is inclined with respect to the surface normal of the hand 6 to be dried. For example, the angle of inclination may be between 15 to near 90 degrees to avoid backscattering of liquid particles and germs 7′ detached from the hand into the exterior space 8.

With reference to FIG. 10, a further embodiment of the air-flow apparatus is shown there, which is based on the embodiments of FIG. 8A and FIG. 9, respectively, wherein only a two-stage nozzle 29 is used at the front and back of the hand 6, respectively. The nozzle shown in the illustration on the right is connected, for example, by a transverse connection 28″ to the inflow pipe 28 or the overpressure pump 27.

The nozzle 29 used in FIG. 10 is shown more clearly in further views in FIG. 11. The nozzle 29 comprises a first flat nozzle 29′ for distributing and accelerating the second air flow 30 from the inflow pipe 28. With reference to FIG. 11, an outlet cross-sectional area 41 of the first flat nozzle 29′ is smaller than a corresponding inlet cross-sectional area 40 and has on the outlet side, compared to the inlet width 40″, a significantly larger width 41″ for distributing the air flow, but a significantly smaller height 41′ than the corresponding height 40′ at the inlet, in order to achieve a first acceleration of the air flow 30. The second flat nozzle 29″, whose inlet cross-section 42 corresponds to the outlet cross-section 41 of the first flat nozzle 29′ and whose outlet cross-section 43 is smaller than the inlet cross-section 42, enables further acceleration of the air flow 30. The width 43″ at the outlet of the second flat nozzle 29″ corresponds to the width 41″, for example.

FIG. 12 shows another embodiment, based on the embodiment example of FIG. 10, with the aim of simplifying the arrangement and maintaining effectiveness. The inlet 31 for the pump 27 for generating a second air flow 30 is connected to the outlet of the unit 17 for decontamination of the output air flow 9, preferably via a valve 16 and a pipe 31′. Here, an embodiment of the plant 17 with a filter system 17′ (e.g., dehumidifier, HEPA filter, UV filter) is used for decontamination and dehumidification of the outlet air flow 9. In this way, a portion of the purified outlet air flow 9 can be used as a second air flow 30, and the filter system 32 upstream of the pump 27 in the preceding embodiments in FIGS. 8A, 9 and 10 can be omitted. Additionally, in this case, the system 17 also includes an outlet 17″ for air 7″ cleaned of germs and dehumidified to the environment 8, and an inlet 17 for air from the environment 8 to the system 17 to provide optimal control of the air flows. In this case, the outlet 17″ can also be used for selective recirculation of the purified room air when the air-flow apparatus is operating in air purification mode.

FIG. 13 shows a further embodiment of the air-flow apparatus in which, in comparison with FIG. 12, the pump 27 is replaced by an electrically controllable valve 44 in order to generate the second air flow 30 only when there is already sufficient negative pressure in the interior space 11′ of the air-flow apparatus by means of the first air flow 7, and also to switch it off again before the pump 15 is switched off. The overpressure generating device is thus formed by the electrically controllable valve 44.

FIG. 14A and FIG. 14B show a further embodiment of an air-flow apparatus in which a power of the vacuum pump 15 can be further reduced by a special design of the lid 12. In this case, the lid 12 has movable elements 33 with deformable parts 36 which allow a space between the hand and the object 6 to be dried, respectively, to be completely or almost completely closed. However, openings 34 are provided in the lid 12, which are preferably in the form of nozzles 35, so as to generate an air flow at high speed on the surface of the hands 6 to be dried also by the sole action of the first air flow 7 generated by the pumps 15. Thereby, the power consumption can be further reduced compared to the previously described embodiments.

However, since the hands 6 to be dried come into contact with the deformable parts 36, it is advantageous to provide an additional cleaning process by means of the injector 19 and the cleaning agent 20 during and following the drying process. This is not mandatory in the previously described embodiments, particularly in connection with FIGS. 8 to 13, since contact between the hand and the air-flow apparatus can be avoided.

Although not explicitly shown, it is also possible in the embodiment of FIGS. 14A and 14B to support the global generation of negative pressure by a local generation of positive pressure to further improve the air flow in the interior space 11′.

The lid in the embodiment of FIGS. 14A and 14B is also a measure that acts in addition to the global negative pressure to prevent the moisture particles and germs 7′ from escaping by flowing back into the inlet opening and then into the environment 8.

FIG. 15 shows a further or alternative embodiment which is essentially based on the embodiment of FIG. 10 and in which the deformable parts 36 of the lid 12 in FIG. 14A are replaced by an “air flow lid” or “air lid” for short 39 which generates a horizontal air flow 45′ by means of at least one additional suction line 45. In this case, the pump 15 is additionally connected to the interior space 11′ on the inlet side via the at least one suction line 45. In this case, the at least one suction line 45 opens near or below the partially opened lid 12 into the interior space 11′ in such a way that a horizontal air flow 45′ parallel or essentially parallel to the lid 12 is generated. This forms the air cover 39, and although a somewhat higher power of the pump 15 may be required, contact of the human hand 6 by deformable parts 36 is avoided, which may thus have hygienic advantages.

The air-flow apparatus according to the invention uses a number of sensors, including sensors 25 that measure air quality in the environment 8, for system control. With reference to FIGS. 16A and 16B, which are based on FIG. 15, this information can not only be used to control the air purification function, but can also be provided by means of a display 46 as information on air quality (Air Quality Index, measured values for gases such as CO2 (including correlation to biological contamination such as viruses, bacteria, VoC, formaldehyde, etc., and even radon) for the users of the air-flow apparatus or hand dryer. Alternatively, the information can be transmitted via radio (not shown) to devices of the user (cell phone, smartwatch, . . . ) for information or warning of hazards.

As described in connection with FIGS. 6A and 6B, an operating mode of the air-flow apparatus can also be controlled in all embodiments via one or more sensors 25 for measuring the germ load or other air quality parameters. For example, the control element 23 is adapted to activate the air purification mode upon detection of the exceeding of a set threshold value of the germ load or other pollution of the air in the exterior space 8 by means of the at least one sensor 25 for measuring the germ load or other parameters of the air quality.

LIST OF REFERENCE SIGNS

6 object

7 air flow

7′ moisture particles and germs

7″ air cleaned from humidity and germs

8 outside space

9 outlet air flow

11 housing

11′ interior space

12 lid

13 bottom

14 perforations

pump

15′ inlet pipe

15″ outlet pipe

16 valve

17 unit

17′ filter area

17″ air outlet

17′″ air supply

18 movable element

19 disinfection device

particle of disinfectant

21 sensor

23 control element

24 valve

sensor

26 insert

27 pump

28 inlet pipe

29 nozzle

29′, 29″ flat nozzle

30 air flow

31 inlet

31′ pipe

32 filter system

33 movable element

34 opening

nozzle

36 deformable part

37, 38 pressure sensor

39 air cap

40-43 dimensions flat nozzle

44 controllable valve

suction line

45′ horizontal air flow

46 display

Number	Date	Country	Kind
10 2021 100 519.1	Jan 2021	DE	national
10 2021 103 265.2	Feb 2021	DE	national

AIR-FLOW APPARATUS

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CPC

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