Patent Publication Number: US-2023158532-A1

Title: Device and method for applying a liquid film to surfaces in an area

Description:
TECHNICAL FIELD 
     The present invention relates to a device for applying a liquid film to surfaces in an area, such as for example a room. Furthermore, the present invention also relates to a method for applying a liquid film to surfaces in an area. 
     BACKGROUND ART 
     An area, such as for example a room, can be treated or disinfected by applying a liquid film containing an active ingredient on the surfaces in the area, such as for example wall surfaces of the area and surfaces of objects in the area. The active ingredient may for example be a biocide, a pesticide, a virucide, a fungicide, an insecticide, a probiotic or an antibiotic. The liquid film is preferably evenly distributed over all the surfaces in the area, such that all the surfaces receive an equal and sufficient treatment. 
     It is known from the state of the art that the liquid film can be applied on surfaces in an area by an operator present in the area by means of a spraying device, such as for example a pressure sprayer, which discharges from a spraying head in a discharge direction a flow of liquid droplets containing the active ingredient. To apply the liquid film, the operator moves the spraying head around such that the discharge direction and thereby the discharged flow of liquid droplets is directed to the different surfaces in the area. The operator can thereby make sure that the liquid film is evenly distributed over all the surfaces in the area, such that all the surfaces receive an equal and sufficient treatment. 
     This does however have the disadvantage that the operator is exposed to the active ingredient, which is in many cases hazardous to the health of the operator. The operator may wear protective gear to avoid exposure to the active ingredient, but such protective gear is cumbersome and time consuming to put on and take off. And even with the protective gear there might still be a risk of the operator being exposed to the active ingredient, for example in case of a tear in the protective gear or by taking off the protective gear without the necessary care. 
     Alternatively, a device can be used which is arranged for applying a liquid film to surfaces in an area autonomously without the presence of an operator. Such devices do however have the disadvantage that they cannot evenly distribute the liquid over the surfaces in the area. 
     DISCLOSURE OF THE INVENTION 
     It is an aim of the present invention to provide a device and method for applying a liquid film to surfaces in an area, which is able to apply the liquid film over to the surfaces in the area such that the liquid film is evenly distributed over the surfaces in the area, and to do this autonomously for improved safety. 
     This aim is achieved according to the invention with a device for applying a liquid film to surfaces in an area showing the technical characteristics of the first independent claim, and with a method for applying a liquid film to surfaces in an area showing the technical characteristics of the second independent claim. 
     Therefore the present invention provides a device for applying a liquid film to surfaces in an area, such as for example a room. The device comprises a head provided for discharging a flow of liquid droplets in a discharge direction. The device is arranged for rotating the head according to two rotational degrees of freedom to move the discharge direction through the area. Preferably, the head is thereby rotatable around a rotation centre located within the head. The device comprises a distance sensor for measuring a distance between the head and surfaces in the area along the discharge direction. The device is configured according to at least one of a first configuration and a second configuration. In the first configuration a rotational speed, preferably at least one rotational speed, of the head is adjustable. In the first configuration the device is arranged to adjust the rotational speed, preferably the at least one rotational speed, of the head as a function of the distance measured by the distance sensor. In the second configuration a flow rate of the flow of liquid droplets from the head is adjustable. In the second configuration the device is arranged to adjust the flow rate of the flow of liquid droplets from the head as a function of the distance measured by the distance sensor. 
     The device according to the present invention offers the advantage that depending on the distance between the head and the surface in the area to which the head is pointing with the discharge direction, the amount of liquid droplets which is discharged towards said surface is adjustable. In the device configured according to the first configuration this is done by adjusting the rotational speed of the head. In this way the flow of liquid droplets discharged from the head can be directed for a long or short time towards the surface, such that for the same flow rate of the flow of liquid droplets respectively more or less of the liquid droplets are discharged towards the surface. In the device configured according to the second configuration this is done by adjusting the flow rate of the flow of liquid droplets from the head, such that for the same rotational speed of the head more or less of the liquid droplets can be discharged towards the surface. In the device configured according to both the first configuration and the second configuration this is done by adjusting one or both of the rotational speed of the head and the flow rate of the flow of liquid droplets from the head. 
     In this way more liquid droplets can be discharged towards surfaces which are far away from the head, for which surfaces the chance that all the liquid droplets discharged from the head reach said surfaces is small because of the large distance, and less liquid droplets can be discharged to surfaces which are close to the head, for which surfaces the chance that all the liquid droplets discharged from the head reach the surface is large because of the short distance. In this way all the surfaces in the area, independent of their distance to the head, will receive an equal amount of the liquid droplets, such that the liquid film is evenly distributed over all the surfaces in the area. 
     In an embodiment of the device according to the present invention the device is arranged in the first configuration to respectively increase or decrease the rotational speed of the head with a decrease or increase of the distance measured by the distance sensor. In the second configuration, the device is arranged to respectively increase or decrease the flow rate of the flow of liquid droplets from the head with an increase or decrease of the distance measured by the distance sensor. 
     In an embodiment of the device according to the present invention the device is arranged in the first configuration to adjust the rotational speed of the head such that the discharge direction sweeps between the head and surfaces in the area an equal predetermined surface area during equal predetermined time intervals when the head is rotated. 
     In an embodiment of the device according to the present invention the head is rotatable around a height direction. The head is rotatable around a transverse direction. The transverse direction is transverse to the height direction and transverse to the discharge direction. 
     In an embodiment of the device according to the present invention at least one of a first rotational speed of the head around the height direction and a second rotational speed of the head around the transverse direction is adjustable in the first configuration. The device is arranged to adjust the at least one rotational speed of the head as a function of the distance measured by the distance sensor. 
     In an embodiment of the device according to the present invention the device comprises a support. The support is rotatable around the height direction. The head is mounted on the support such that the head is rotatable around the height direction together with the support. The head is mounted on the support such that the head is rotatable around the transverse direction. 
     In an embodiment of the device according to the present invention the head comprises a supply opening at a first end of the head in the discharge direction. The head comprises a discharge opening at a second end of the head in the discharge direction opposite of the first end of the head. The head comprises a suction device arranged for sucking an airflow into the head from the supply opening to the discharge opening. The head comprises a nebulizer arranged for adding the liquid droplets to the airflow through the head. 
     In an embodiment of the device according to the present invention the suction device is arranged for sucking the airflow into the head from the supply opening to the discharge opening at an adjustable speed in the second configuration for adjusting the flow rate of the flow of liquid droplets from the head. In an embodiment of the device according to the present invention the nebulizer is arranged for adding the liquid droplets to the airflow through the head with an adjustable flow rate in the second configuration for adjusting the flow rate of the flow of liquid droplets from the head. 
     In an embodiment of the device according to the present invention the suction device is arranged for sucking the airflow into the head from the supply opening to the discharge opening such that the airflow flows out of the head in the discharge direction at a speed of at least 5 m/s, preferably at least 10 m/s, more preferably at least 15 m/s, and/or of at most 35 m/s, preferably at most 30 m/s, more preferably at most 25 m/s, even more preferably at most 20 m/s, and most preferably of 18 m/s. 
     The airflow out of the head having a speed in the given range is beneficial to assure that the airflow is a laminar flow. In this way undesirable turbulences are avoided and the time between the discharge of liquid droplets from the head and the contacting of the liquid droplets to the surface is kept in an optimal range. It has been found that the airflow speeds mentioned herein assure that liquid droplets splash open when contacting the surface and provide an even wetting of the surface. Furthermore, the airflow speeds mentioned herein prevent significant evaporation of the liquid droplets before contacting the surfaces in the area. Additionally, in embodiments wherein the liquid droplets are discharged from the head with a surplus or a deficit in electron charge with respect to ground, the airflow speeds mentioned herein assure that a sufficient charge is maintained during the travel of liquid droplets from the head to the surfaces. 
     In an embodiment of the device according to the present invention the suction device is one of an axial fan, a radial fan, a mixed flow fan and a turbine. 
     In an embodiment of the device according to the present invention the head comprises guiding fins for guiding the airflow through the head. Preferably, the guiding fins are curved guiding fins. 
     The guiding fins are beneficial for guiding the airflow through the head in a smooth manner to assure that the airflow is a laminar flow. In this way undesirable turbulences are avoided and the time between the discharge of liquid droplets from the head and the contacting of the liquid droplets to the surface is kept in an optimal range. It has been found that the airflow speeds mentioned herein assure that liquid droplets splash open when contacting the surface and provide an even wetting of the surface. Furthermore, the airflow speeds mentioned herein prevent significant evaporation of the liquid droplets before contacting the surfaces in the area. Additionally, in embodiments wherein the liquid droplets are discharged from the head with a surplus or a deficit in electron charge with respect to ground, the airflow speeds mentioned herein assure that a sufficient charge is maintained during the travel of liquid droplets from the head to the surfaces. 
     In an embodiment of the device according to the present invention the nebulizer is one of a nebulizing rotating disc or cup, a nozzle and a vibration nebulizer. 
     In an embodiment of the device according to the present invention the nebulizer is arranged for adding the liquid droplets to the airflow through the head at a flow rate of at least 0.05 l/min, preferably at least 0.1 l/min, more preferably at least 0.2 l/min, even more preferably at least 0.3 l/min, yet even more preferably at least 0.4 l/m, and/or of at most 50 l/min, preferably at most 25 l/min, more preferably at most 10 l/min, even more preferably at most 5 l/min, yet even more preferably 1 l/min, and most preferably of 0.5 l/min. 
     In an embodiment of the device according to the present invention the liquid droplets have a size of at least 0.5 μm, preferably at least 10 μm, more preferably at least 20 μm, even more preferably at least 40 μm, yet even more preferably at least 80 μm, and/or of at most 5000 μm, preferably at most 2000 μm, more preferably at most 1000 μm, even more preferably at most 500 μm, yet even more preferably at most 200 μm, and most preferably of 100 μm. 
     In an embodiment of the device according to the present invention the liquid droplets are discharged out of the head with a surplus or a deficit in electron charge with respect to ground. 
     This embodiment offers the advantage that the electrostatically charged liquid droplets are attracted to the surfaces in the area for a good application of the liquid film to said surfaces. More in particular, the electrostatically charged droplets allow the droplets to reach and wet surfaces that are not oriented towards the head. For example, it has been found that if the device is used in a room wherein a screen is present, not only the screen surface oriented towards the device, but also the opposite, back surface of the screen is wetted. Electrostatically charged liquid droplets flow over and by the side of the screen and are attracted to the back surface, thereby wetting that surface as well. 
     In an embodiment of the device according to the present invention the liquid droplets comprise at least one active ingredient selected from the list consisting of a biocide, a pesticide, a virucide, a fungicide, an insecticide, a probiotic and an antibiotic. 
     In an embodiment of the device according to the present invention the distance sensor is configured to measure the distance by means of electromagnetic waves or sound waves. Preferably the electromagnetic waves are light waves or microwaves. More preferably, the electromagnetic waves are laser light waves. Preferably, the sound waves are ultrasound waves. 
     In an embodiment of the device according to the present invention the distance sensor is attached to the head to rotate with the head. 
     This embodiment offers the advantage that the distance sensor automatically moves together with the head when the head is being rotated to move the discharge direction through the area, such that the distance sensor is always correctly positioned for measuring the distance between the head and the surface in the area to which the discharge direction is pointing. 
     Furthermore, the present invention also provides a method for applying a liquid film to surfaces in an area, such as for example a room, by means of the device according to the present invention. The method comprises a first step of rotating the head to move the discharge direction through the area. Thereby, the distance sensor is rotated with the head for measuring the distance between the head and surfaces in the area with the distance sensor for the different positions of the discharge direction. The method comprises discharging a flow of liquid droplets in the discharge direction from the head, either during the first step of rotating the head to move the discharge direction through the area, or during a second step of rotating the head to move the discharge direction again through the area. Thereby, the rotational speed of the head is adjusted as a function of the distance measured by the distance sensor during the first step of rotating the head in the first configuration, and the flow rate of the flow of liquid droplets from the head is adjusted as a function of the distance measured by the distance sensor during the first step of rotating the head in the second configuration. 
     Furthermore, the present invention provides methods as described herein, wherein the device is stationary in relation to the surfaces in the area during the method. In particular, the device may comprise a support that is stationary in relation to the surfaces in the area during the method. Thus, according to a particular embodiment, the present invention provides the methods described herein, wherein the device is positioned at a predetermined position in the area. 
     In an embodiment of the method according to the present invention the step of discharging the flow of liquid droplets in the discharge direction from the head is performed during the first step of rotating the head to move the discharge direction through the area. 
     In a preferred embodiment, the method comprises a first step of measuring the distance between the head and the surfaces as described herein and a second step of discharging liquid droplets as described herein. Performing a first step of measuring the distance and a second step of discharging avoids that discharged liquid droplets interfere with distance measurements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be further elucidated by means of the following description and the appended figures. 
         FIG.  1    shows a perspective view of a device according to an embodiment of the present invention. 
         FIG.  2    shows a cross section through the head of the device of  FIG.  1   . 
     
    
    
     MODES FOR CARRYING OUT THE INVENTION 
     The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not necessarily correspond to actual reductions to practice of the invention. 
     Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. The terms are interchangeable under appropriate circumstances and the embodiments of the invention can operate in other sequences than described or illustrated herein. 
     Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. The terms so used are interchangeable under appropriate circumstances and the embodiments of the invention described herein can operate in other orientations than described or illustrated herein. 
     The term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B. 
       FIG.  1    shows a device  100  according to an embodiment of the present invention for applying a liquid film to surfaces in an area. The area may for example be a room. The surfaces may for example be wall surfaces of the area and surfaces of objects in the area. The device  100  comprises a head  110  that is provided for discharging a flow of liquid droplets  200  in a discharge direction D. The head  110  is mounted on a support  130  of the device  100 . On the support  130  there is provided a reservoir  140  for the liquid which is used for applying the liquid film by means of the device  100 . 
     The head  110 , as shown in further detail in  FIG.  2   , comprises a housing  113  which encloses an internal volume  114  of the head  110 . At a first end  111  in the discharge direction D the housing  113  of the head  110  is provided with a supply opening  115  leading into the internal volume  114 . At a second end  112  in the discharge direction D, opposite of the first end  111  in the discharge direction d, the housing  113  of the head  110  is provided with a discharge opening  116  leading out of the internal volume  114 . 
     Inside the internal volume  114  the head  110  is provided at the supply opening  115  with a suction device  117  that is arranged for sucking an air flow  300  into the internal volume  114  of the head  110  via the supply opening  115 . This airflow  300  is further directed through the internal volume  114  towards the discharge opening  116 , and out of the discharge opening  116  along the discharge direction D. 
     Preferably, the suction device  117  is arranged for sucking the airflow  300  into the head  110  from the supply opening  115  to the discharge opening  116  such that the airflow  300  flows out of the head  110  in the discharge direction D at a speed of at least 5 m/s, preferably at least 10 m/s, more preferably at least 15 m/s, and/or of at most 35 m/s, preferably at most 30 m/s, more preferably at most 25 m/s, even more preferably at most 20 m/s, and most preferably of 18 m/s. 
     In the embodiment shown, the suction device  117  is an axial fan, but in alternative embodiments any other suitable type of suction device  117  known to the skilled person can be used, such as for example a radial fan, a mixed flow fan or a turbine. 
     Optionally, the head  110  can be provided with guiding fins  119  inside the internal volume  114 , preferably curved guiding fines  119 , on the inner surface of the housing  113  following the suction device  117  in the discharge direction D. These guiding fins  119  aid in guiding the airflow  300  through the internal volume  114  from the suction device  117  to the discharge opening  116 . 
     Inside the internal volume  114 , the head  110  is provided at the discharge opening  116  with a nebulizer  118  that is arranged for adding liquid droplets  200  to the airflow  300  passing through the internal volume  114  of the head  110  to form the flow of liquid droplets  200  that is discharged out of the head  110  in the discharge direction D. 
     Preferably, the nebulizer  118  is arranged for adding the liquid droplets  200  to the airflow  300  through the head  110  at a flow rate of at least 0.05 l/min, preferably at least 0.1 l/min, more preferably at least 0.2 l/min, even more preferably at least 0.3 l/min, yet even more preferably at least 0.4 l/m, and/or of at most 50 l/min, preferably at most 25 l/min, more preferably at most 10 l/min, even more preferably at most 5 l/min, yet even more preferably 1 l/min, and most preferably of 0.5 l/min. 
     Preferably, the liquid droplets  200  have a size of at least 0.5 μm, preferably at least 10 μm, more preferably at least 20 μm, even more preferably at least 40 μm, yet even more preferably at least 80 μm, and/or of at most 5000 μm, preferably at most 2000 μm, more preferably at most 1000 μm, even more preferably at most 500 μm, yet even more preferably at most 200 μm, and most preferably of 100 μm. 
     Preferably, the nebulizer  118  is arranged for electrostatically charging the liquid droplets  200 , such that the liquid droplets  200  are discharged out of the head  110  with a surplus or a deficit in electron charge with respect to ground. Arranging the nebulizer for electrostatically charging the liquid droplets has been found to be particularly convenient, although the skilled person is aware of other possibilities for electrostatically charging liquid droplets, which is also within the scope of the invention. Electrostatically charging the liquid droplets  200  has the advantage that the liquid droplets  200  are attracted to the surfaces in the area for a good application of the liquid film to said surfaces by means of the device  100 . 
     Preferably, the liquid droplets  200  comprise at least one active ingredient selected from the list consisting of a biocide, a pesticide, a virucide, a fungicide, an insecticide, a probiotic and an antibiotic. 
     The nebulizer  118  may for example be a nebulizing disc, a nozzle, or a vibration nebulizer, but any other suitable type of nebulizer  118  known to the skilled person can be used. 
     The device  100  is arranged such that the head  110  is rotatable according to two rotational degrees of freedom to be able to move the discharge direction D of the head through the area. Therefore, the support  130  on which the head  110  is mounted, is arranged such that the support  130  is rotatable around a height direction H along an azimuth angle θ. The head  110  is mounted on the support  130  in such a way that the head  110 , and thus also the discharge direction D of the head  110 , rotates together with the with the support along the height direction H along the azimuth angle θ, i.e. the first rotational degree of freedom. The head  110  is also mounted on the support  130  such that the head  110 , and thus also the discharge direction D of the head  110 , is tiltable or rotatable around a transverse direction T along an inclination angle φ, i.e. the second rotational degree of freedom. Thereby, this transverse direction T is perpendicular to both the height direction H and the discharge direction D. Preferably, the rotation centre  150  of the head  110  is located within the internal volume  114  of the head, such as shown in  FIG.  2   . 
     On top of the housing  113  the head  110  is provided at the discharge opening  116  with a distance sensor  120 . The distance sensor  120  is configured for measuring along the discharge direction D a distance d between the head  110  and a surface in the area to which the head  110  is pointing with the discharge direction D. The distance sensor  120  is attached to the head  110  such that, when the head  110  is rotated for moving the discharge direction D through the area, the distance sensor  120  will move together with the head  110  for measuring the distance d along the discharge direction D. 
     The distance sensor  120  may be configured to measure the distance d between the head  110  and a surface in the area by means of electromagnetic waves or sound waves which are transmitted by the distance sensor  120  in the discharge direction D and reflected on the surface back to the distance sensor  120 , where the reflected electromagnetic or sound waves are detected. The time which has passed between the transmittal of the electromagnetic or sound wave and the detection of the reflected electromagnetic or sound wave can then be used to determine the distance d between the head  110  and the surface. The electromagnetic waves may for example be microwaves or light, such as laser light, and the sound waves may for example be ultrasound waves. 
     To be able to evenly distribute the liquid film over the surfaces in an area, the device  100  is configured according to at least one of a first configuration and a second configuration. 
     In the first configuration the device  100  is arranged in such a way that a rotational speed of the head  110  is adjustable. Said rotational speed may be a first rotational speed of the head  110  around the height direction H, i.e. along the azimuth angle θ. Said rotational speed may also be a second rotational speed of the head  110  around the transverse direction T, i.e. along the inclination angle φ. Said rotational speed may also be both the first rotational speed and the second rotational speed. The device  100  is thereby arranged to adjust said rotational speed as a function of the distance d measured by the distance sensor  120 . Thereby, the device  100  is configured to increase said rotational speed when the distance d between the head  110  and surfaces in the area decreases, and vice versa to decrease said rotational speed when the distance d between the head  110  and surfaces in the area increases. This may for example be done by adjusting the rotational speed of the head  110  in such a way that the discharge direction D sweeps between the head  110  and surfaces in the area, i.e. over the distance d, an equal predetermined surface area during equal predetermined time intervals when the head is rotated. As such, the device  100  will take a longer time to apply a liquid film on surfaces in the area which are further away from the head  110  than to surfaces in the area which are closer to the head  110 . This is beneficial because with an increased distance d from the head  110  the chance of the liquid droplets  200  that are being discharged from the head  110  reaching the target surface decreases. Moving the head  110  slower for surfaces which are further away will then make sure that those further surfaces receive an equal amount of the liquid droplets  200  as surfaces which are closer by. As such the liquid film is evenly distributed over all the surfaces in the area. 
     In the second configuration the device  100  is arranged in such a way that a flow rate of the flow of liquid droplets from the head  110  is adjustable. This may for example be done by providing the suction device  117  of the head  110  for sucking the airflow  300  into the head  110  from the supply opening  115  to the discharge opening  116  at an adjustable speed, and/or by providing the nebulizer  118  for adding the liquid droplets  200  to the airflow  300  through the head  110  with an adjustable flow rate. The device  100  is thereby arranged to adjust the flow rate of the flow of liquid droplets  200  from the head  110  as a function of the distance d measured by the distance sensor  120 . Thereby, the device  100  is configured to increase the flow rate of the flow of liquid droplets  200  from the head  110  when the distanced between the head  110  and surfaces in the area increases, and vice versa to decrease the flow rate of the flow of liquid droplets  200  from the head  110  when the distance d between the head  110  and surfaces in the area decreases. This is beneficial because with an increased distance d from the head  110  the chance of the liquid droplets  200  that are being discharged from the head  110  reaching the target surface decreases. Increasing the flow rate of the flow of liquid droplets  200  being discharged from the head  110  for surfaces which are further away will then make sure that those further surfaces receive an equal amount of the liquid droplets  200  as surfaces which are closer by. As such the liquid film is evenly distributed over all the surfaces in the area. 
     For applying a liquid film to surfaces in an area, such as a room, the device  100  can be used as follows. 
     First, the device  100  is positioned in the area by an operator, preferably as centrally as possible. Then, the operator makes sure that all the devices in the area which have a fan, such as for example a personal computer, a copy machine, air-conditioner, etc. are turned off, because the fan might disturb the process of applying the liquid film on the surfaces in the area by means of the device  100 . Then, the operator makes sure that any openings to the area, such as doors or windows are closed before leaving the area. 
     After this has been done the device  100  is started. This may for example be done remotely by the operator via an application on a mobile phone or other suitable computing device. This may also be done by the operator activating the device  100  when the operator is still present in the area, and the device automatically starting after a predetermined time which allows the operator to leave the area in time. 
     After the device  100  is started, the head  110  is rotated around the transverse direction T to a horizontal position, i.e. such that the discharge direction D is located in a horizontal plane, and this without the head  110  discharging a flow of liquid droplets  200  in the discharge direction D. Thereafter, the head  110  is rotated full circle around the height direction H, i.e. over 360° of the azimuth angle θ, to move the discharge direction D through the area, and this also without the head  110  discharging a flow of liquid droplets  200  in the discharge direction D. While the head  110  is being rotated around the height direction H, the distance sensor  120 , which moves together with the head  110 , measures at predetermined intervals, for example of 1° azimuth angle θ, the distance d between the head  110  and a surface in the area to which the head  110  and thus the discharge direction D is pointing. The measured distances d are stored in a memory of the device  100  for later use. 
     In the next step, the head  110  is rotated again full circle around the height direction H, i.e. over 360° of the azimuth angle θ, to move the discharge direction D through the area, but this time with the head  110  discharging a flow of liquid droplets  200  in the discharge direction D for applying a liquid film on the surfaces in the area along said full circle. In the first configuration of the device  100 , a rotational speed of the head  110 , in this case the first rotational speed, is thereby adjusted, as described in further detail above with respect to the first configuration, as a function of the previously measured distances d to evenly distribute the liquid film on the surfaces in the area along said full circle. In the second configuration of the device  100 , the flow rate of the flow of liquid droplets  200  from the head  110  is thereby adjusted, as described in further detail above with respect to the second configuration, as a function of the previously measured distances d to evenly distribute the liquid film on the surfaces in the area along said full circle. Alternatively, this step may be performed together with the previous step of rotating the head  110  full circle around the height direction H, in which case the instantaneously measured distances d would be used for adjusting the rotational speed of the head  110  in the first configuration of the device  100 , and for adjusting the flow rate of the flow of liquid droplets  200  from the head  110  in the second configuration of the device  100 . 
     The abovementioned steps of measuring the distances d to the surfaces in the area and applying the liquid film to the surfaces in the area, are then repeated for different inclination angles φ of the head  110  above and below the horizontal plane until the liquid film is applied to all the surfaces in the area. This may for example be done in intervals of 20° of the inclination angle φ. It should hereby also be noted that it is not preferably to rotate the head  110  straight down, since there the support  130  is located, to which no liquid film has to be applied. 
     It should be noted that the head  110  can also be rotated in other ways to move the discharge direction D through the entire area. One option, for example, is to rotate the head  110  first almost full circle around the transverse direction T, i.e. over almost 360° of the inclination angle φ, taking into account the presence of the support  130  to which no liquid film has to be applied. This rotation of the head  110  is then repeated at different intervals of the azimuth angle θ of the head  110 . Another option, for example, is to rotate the head  110  simultaneously around the height direction H and the transverse direction T, and this in such a way that the discharge direction D is moved along a spherical spiral. 
     After the liquid film has been applied to the surfaces in the entire area, the applied liquid film is given a predetermined period, for example half an hour, to dry. Thereby, the device  100  can be used to speed up the drying of the liquid film, by moving the head  110  around while it discharges only an airflow  300 . If the predetermined period has lapsed, the device  100  informs the operator, for example via an application on a mobile phone or other suitable computing device, that the procedure has finished and that it is safe to enter the room. 
     
       
         
           
               
             
               
                   
               
               
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                 100 
                 device 
               
               
                   
                 110 
                 head 
               
               
                   
                 111 
                 first end 
               
               
                   
                 112 
                 second end 
               
               
                   
                 113 
                 housing 
               
               
                   
                 114 
                 internal volume 
               
               
                   
                 115 
                 supply opening 
               
               
                   
                 116 
                 discharge opening 
               
               
                   
                 117 
                 suction device 
               
               
                   
                 118 
                 nebulizer 
               
               
                   
                 119 
                 guiding fin 
               
               
                   
                 120 
                 distance sensor 
               
               
                   
                 130 
                 support 
               
               
                   
                 140 
                 reservoir 
               
               
                   
                 150 
                 rotation centre 
               
               
                   
                 200 
                 liquid droplets 
               
               
                   
                 300 
                 airflow 
               
               
                   
                 D 
                 discharge direction 
               
               
                   
                 H 
                 height direction 
               
               
                   
                 T 
                 transverse direction 
               
               
                   
                 d 
                 distance 
               
               
                   
                 θ 
                 azimuth angle 
               
               
                   
                 φ 
                 inclination angle