Patent Publication Number: US-2023142979-A1

Title: Hygienic process for an air supply system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to German Patent Application No. DE 102021129184.4 filed Nov. 10, 2021, the disclosure of which is hereby incorporated in its entirety by reference herein. 
     TECHNICAL FIELD 
     The invention relates to an air blower apparatus, in particular, to a jet air hand dryer. 
     BACKGROUND 
     Air blower apparatuses are used in air handling systems, for example, to ventilate rooms in buildings. Such air blower apparatuses are used to control the exchange of air inside a room, thus also allowing the climatic conditions in the room to be adjusted at the same time. Such air blower apparatuses are also used in the sanitary field as jet air hand dryers, which deliver a stream of air used to dry hands. 
     An air blower apparatus having a base member with an air inlet and an air outlet is known, for example, from DE 20 2018 001 847 U1, in which a treatment chamber is provided between the air inlet and the air outlet. A UV treatment unit for disinfecting the air stream passing through the air blower apparatus is arranged inside the treatment chamber. 
     A hand dryer having a housing is also shown in DE 10 2017 009 637 A1, for example. A hollow space which is accessible from the outside through a housing opening is provided in the housing, for receiving hands to be dried, onto which a stream of air produced by a fan is directed. Also arranged inside the hollow space is a device for producing UV radiation, which is designed to emit UV radiation for disinfecting hands that are inserted into the hollow space. 
     Described herein is an air blower apparatus and also a method of disinfecting an air stream passing through an air handling system, by means of which an air stream passing through the air blower unit is disinfected efficiently and above all in a permanently reliable manner. 
     SUMMARY 
     An jet air hand dryer may include a housing having an inlet and an outlet, at least one air duct extending inside the housing between the inlet and the outlet, for guiding an air stream, a fan unit for producing a directed stream of air in the air duct, and a UV treatment unit arranged inside a section of the air duct, said UV treatment unit having a treatment chamber for at least parts of the stream passing through the air duct. Also disclosed is a method of disinfecting an air stream passing through an air handling system. 
     According to a first aspect, an air blower apparatus, such as jet air hand dryer, may include a housing having an inlet and an outlet. At least one air duct extends inside the housing between the and the outlet for guiding an air stream. A fan unit produces a directed stream of air in the air duct. The apparatus further includes a UV treatment unit arranged inside a section of the air duct. The UV treatment unit has a treatment chamber for at least parts of the air stream passing through the air duct. The treatment chamber is at least part of a receiving chamber for a fan impeller in the fan unit, wherein a plurality of UV light sources are arranged inside the receiving chamber. In some embodiments, the treatment chamber through which at least parts of the air stream flow through the air duct is part of a receiving chamber for a fan impeller in the fan unit, wherein a plurality of lighting means adapted to emit UV light are arranged inside the receiving chamber. 
     The in the disclosed approach, disinfection is not limited, due to the UV treatment unit, only to at least parts of the air passed through the air blower apparatus, and thus an arbitrary section of the air blower apparatus, but that disinfection with UV light is performed in a special section of the air blower apparatus. For example, disinfection of parts of the air stream and of the air blower apparatus is carried out in the region that the air stream must inevitably pass through when the directed and forced air stream is produced by the air blower apparatus. This results in efficient, and above all, permanently reliable disinfection in the region, namely in the fan unit, that comes into contact with the air stream over a relatively large area. In addition to the air stream itself, regions of the fan unit, particularly surfaces of the fan unit, may also disinfected by the UV light. 
     According to an example embodiment of the invention, the lights of the UV treatment unit are directed in the receiving chamber towards the fan impeller. As a result, the UV light may be directed towards the part of the fan unit that is used to produce the air stream inside the air blower apparatus. The fan impeller, for example, which is the component of the air blower apparatus that comes into contact over a relatively large area with the air stream passed through the air blower apparatus, is thus exposed to UV light and therefore disinfected. Exposing the fan impeller to UV light further improves the disinfection effect achieved by the air stream passed through the air blower apparatus. 
     According to another embodiment, the lighting sources are directed towards an outer circumferential surface of the fan housing such that the UV light emitted by the lighting sources hits the surfaces of the fan impeller vanes and/or radiates into the interspaces between the fan impeller vanes. By pointing the lighting sources at the outer circumferential surface of the fan impeller, a large proportion of the UV light emitted by the lighting sources of the UV treatment unit reaches almost the entire surface of the fan impeller. The disinfection effect is further improved as a consequence. 
     In a yet another embodiment, the lighting sources are arranged on a curved path, e.g., a circular path, around an outside of the fan impeller and radiate in the direction of a center point defined by the curved path. This arrangement has the effect that the fan impeller vanes of the fan impeller are exposed, in some instances over their entire surface, to the UV light. The lighting sources may be arranged on the circular path around the outside of the fan impeller in such a way that the interspaces between the fan impeller vanes are also completely irradiated. When the fan impeller rotates and the air stream is produced, the entire surface of the fan impeller conveying the air stream may be exposed to UV light of the UV treatment unit and the interspaces completely irradiated at the same time. The disinfection effect achieved by the UV treatment unit may be increased as a result. 
     The fan unit may be a centrifugal fan, and the lighting sources are preferably arranged at intervals (spaced apart) from one another on a circumferential surface of the receiving chamber surrounding the fan impeller on its outside. By providing a centrifugal fan, it is possible to combine in an advantageous manner the irradiation of the surface of the fan impeller vanes and also the irradiation of the air stream flowing radially outwards between the fan impeller vanes. The lighting may be arranged at intervals along the circumferential surface of the receiving chamber for the fan impeller, whereby at least a quarter, or more than half, of the outer circumferential surface of the receiving chamber surrounding the fan impeller is fitted with lighting sources. At least half of the surface of the stationary fan impeller may be exposed to the UV light that produces the disinfection effect. 
     The receiving chamber may be substantially cylindrical in shape, and the fan impeller may be arranged off-center in the receiving chamber. The lighting sources may be arranged, at increasingly large intervals in the direction of the outlet, on the circumferential surface of the receiving chamber encasing the fan impeller. Due to the off-center arrangement, the distance between the circumferential surface of the fan impeller and the circumferential surface of the receiving chamber surrounding the fan impeller gradually widens, with the largest distance being found in the region of the outlet. As the distance of the circumferential surface of the receiving chamber from the circumferential surface of the fan impeller increases, the selected distance between the lighting sources arranged on the circumferential surface can be greater, because with increasing distance from the outer circumferential surface of the fan impeller, the surface area irradiated by the light emitted from the lighting means onto the fan impeller increases. The distance between the outer circumferential surface of the receiving chamber and the circumferential surface of the fan impeller is preferably smallest in the transition region between the outlet and the housing portion that then adjoins in the direction of rotation of the fan impeller. 
     According to a development of the air blower apparatus, the lighting sources are designed to emit light with a wavelength in the UV-C range from 100 nm to 280 nm. The lighting sources may be UV lights, e.g., UV-C light emitting diodes (LED), that may be arranged in electrical communication with each other on a flexible strip of material. A simple way of producing the UV light is to provide UV-C diodes as the lighting sources, by means of which the fan impeller and the air stream passing through the air blower apparatus can be disinfected. Using diodes also results in a long service life of the lighting means, thus resulting in low-maintenance operation of the air blower apparatus. 
     The UV-C light emitting diodes may emit light with a wavelength ranging from 100 nm to 280 nm, such as in the range of 200 nm to 280 nm, in the range between 240 nm and 270 nm, or with a wavelength of about 254 nm. In the present case, “about” should be understood as the UV light being emitted in the range of 254 nm +/−5%. The above specifications are to be understood here to mean that, light is emitted by means of the UV-C diodes predominantly in the specified range, whereby lower intensity light may also be emitted in adjacent regions. 
     According to a further embodiment of the air blower apparatus, the housing has at least two housing portions, wherein the two housing portions are connected sealingly to each other a strip of material. The multi-part housing design simplifies installation of the air blower apparatus, in that, components of the air blower apparatus to be arranged accordingly inside the housing can be easily inserted into a housing that consists of two half-shells, for example. 
     The housing of the air blower apparatus may be consisting of at least two housing portions that is sealed by means of a flexible strip of material so that the UV light produced inside the treatment chamber of the UV treatment unit is prevented from escaping from the interior of the treatment chamber of the air blower apparatus. In one embodiment, the flexible strip of material is the strip of material on which the lights are arranged in electrical communication with each other. The flexible material strip may also form a part of the receiving chamber encasing the circumferential surface of the fan impeller on its outside. 
     According to an example embodiment of the air blower apparatus, at least the treatment chamber inside the air duct has a material that reflects the UV light emitted from the lighting sources. For example, parts of the receiving chamber for the fan impeller and also, where relevant, the fan impeller itself are lined with a reflective material or coated with a paint that reflects UV light. With the aid of the reflective material, reflection inside the housing and/or by the surface of the fan impeller is multiply increased, so the UV light is increased in intensity and can reach regions of the fan unit that are not irradiated directly by the lighting sources of the UV treatment unit. Increased reflection also results in a further improvement in the disinfection effect on the air stream conducted through the apparatus and on the fan impeller in an air blower apparatus designed in this way. A reflective foil, for example, can be applied as the reflective material to the inner side of the fan unit housing portions forming the receiving chamber. In an alternative embodiment, the reflective material can be applied to the housing and/or the surface of the fan impeller in the form of a coating on the inner side of the receiving chamber. In another alternative embodiment, the fan impeller and the housing surrounding the fan impeller may be made of anodized aluminum, with the inner side consisting of polished material to improve its reflective properties. 
     According to another example embodiment, the air blower apparatus further includes a heating device for heating the air stream flowing through the air duct and/or a detection means associated with the outlet at the air duct, comprising at least one sensor for sensing at least the presence of an object approaching the outlet. With the aid of the heating device, the air stream flowing through the air duct can be heated in a simple manner. In an air blower apparatus used as a jet air hand dryer, the drying effect produced by the air discharged from the outlet of the air blower apparatus can be improved by the heated air stream. 
     With the aid of a detection means (e.g., a proximity detector or motion sensor) associated with the outlet of the air duct, which may have at least one sensor for sensing at least the presence of an object approaching the outlet, when the presence of the detected object is sensed, at least the fan unit is switched on so as to produce an air stream discharged from the outlet of the air blower apparatus. 
     If an object moves out of the detection range of the detection means, i.e., is no longer sensed by the sensor of the detection means, the air blower apparatus is configured to switch OFF, such as after a predetermined stopping time, at least the fan unit for producing the air stream and also, where applicable, the UV treatment unit previously switched on concurrently. 
     The sensor of the detection means may be embodied as a photodiode, for example. 
     According to one embodiment of the disclosure, the air blower apparatus includes a control unit for controlling at least one drive means that drives the fan impeller, the heating device and/or the treatment unit. The control unit may be coupled in electric communication with the detection means and/or with at least a signal receiving means. In a preferred embodiment, the drive means for the fan impeller, the heating device and also the treatment unit are controlled with the aid of the control unit. The control unit can may be used to adjust different processes or programs on the air blower apparatus, with which one, two, or all three components can be controlled simultaneously as required. 
     According to a development of the disclosure, the control unit is coupled to a detector that includes a sensor that detects whether an object is approaching the outlet of the air blower apparatus. The control unit may be coupled in electric communication with a signal receiver, such that the air blower apparatus can be activated by a separate portable communication device, such as a mobile communication device, that communicates with the signal receiver. In addition to the programs stored permanently in the control unit, a query or targeted activation for performing a function check on the air blower apparatus can be transmitted to or carried out on the control unit by a person responsible for maintenance. In addition, further additional functions or programs can also be transmitted to the control unit and stored in its memory via the signal receiving device. 
     According to a second aspect, a method of disinfecting an air stream passing through an air handling system is disclosed. An air blower apparatus according to any of the above-described embodiments described above is arranged inside the air handling system. 
     The disclosure thus proposes a method of disinfecting an air stream passing through an air handling system, in which the air stream to be produced is disinfected inside the components that are primarily involved in producing the forced flow of air. Furthermore, in comparison with the other components of the air handling system, and due to its rotational movement, a significantly greater proportion of the fan unit, e.g., the fan impeller, comes into contact with the air conducted through the air blower apparatus than is the case with any sections of the air duct in the air blower apparatus extending upstream or downstream from the fan unit. The fan unit thus poses a correspondingly high risk of contamination for the air passing through it, which is counteracted with the method according to the invention by UV light being emitted by a plurality of lighting sources arranged inside the receiving chamber for the fan impeller of the fan unit. For example, the UV-C light produced by means of the lighting means is emitted onto the outer circumferential surface of the fan impeller and thus onto the surface of the fan impeller vanes and into the interspaces between the fan impeller vanes. 
     According to one embodiment, a method includes one or more or all of the following steps: driving the fan impeller and simultaneously actuating the lighting sources to produce a UV light for disinfecting an air stream flowing through an air duct; driving the fan impeller and simultaneously actuating the lighting sources to produce the UV light for disinfecting the air stream flowing through the air duct and actuating a heating device for heating the air stream; driving the fan impeller and simultaneously actuating the lighting source to produce the UV light for disinfecting the air stream flowing through the air duct and actuating a heating device for heating the air stream for a specified period of time, wherein, after the specified period of time has elapsed, the heating device is switched OFF and the fan impeller is driven at a reduced speed with the lighting sources still switched ON, and actuating the lighting sources to produce the UV light for disinfecting the fan impeller when the fan impeller is stationary. Different operating modes can be run on the air blower apparatus by applying the various steps listed above. For example, if the fan unit is switched OFF and the lighting sources for producing the UV light is switched ON, disinfection is performed solely on the interior of the air blower apparatus. 
     All other operating modes in which the fan impeller rotates and a directed air stream from the inlet towards the outlet is produced and the air blower apparatus is used, in particular, as a jet air hand dryer, the air stream produced is dispensed onto an object which is brought into the proximity of the outlet, such as a pair of hands to be dried. Due to the disinfection process carried out inside the air blower apparatus, the air stream produced is almost free of harmful or health-endangering elements, such as pathogens. 
     The embodiments and developments of the air blower apparatus according to the first aspect of the invention are at the same time also embodiments of the method according to the second aspect of the invention, insofar as they should not contradict each other. The embodiments and developments described with reference to the second aspect of the invention are at the same time also embodiments of the air blower apparatus according to the first aspect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows a perspective view of a first embodiment of an air blower apparatus according to the disclosure. 
         FIG.  2    shows a schematic view of the air blower apparatus shown in  FIG.  1   , in cross-section. 
         FIG.  3    shows a perspective view of another embodiment of an air blower apparatus according to the disclosure. 
         FIG.  4    shows a cross-sectional view of the air blower apparatus shown in  FIG.  3   . 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows an air blower apparatus, such as a jet air hand dryer for producing a forced air stream. Air blower apparatus  10  includes a housing  12  having an inlet  14  and an outlet  16  and an air duct extending inside housing  12  between inlet  14  and outlet  16 . A fan unit  20  is arranged inside housing  12  and has a fan impeller  22  that circulates an air stream  23  in air duct  18  from the inlet in the direction of the outlet. 
     Air blower apparatus  10  also includes a UV treatment unit  24  that is arranged inside a section of air duct  18 . The UV treatment unit includes a treatment chamber  26  for at least parts of the air stream  23  passing through air duct  18 . 
     In the embodiment shown in  FIG.  1   , the treatment chamber  26  is part of a receiving chamber for the fan impeller  22  of fan unit  20 . A plurality of lighting sources  30  designed to emit UV light are arranged inside receiving chamber  28 . 
     As illustrated in  FIG.  2   , the lighting sources  30  in receiving chamber  28  for the fan impeller are aimed directly at fan impeller  22 . Fan impeller  22  has a plurality of fan impeller vanes  32  and interspaces  34  between adjacent fan impeller vanes, through which air drawn in, in particular in the center of fan impeller  22 , is transported radially to the outside. In the present embodiment, fan unit  20  is designed as a centrifugal fan. 
     Lighting sources  30  are aimed at the outer circumferential surface of the fan impeller in such a way that the UV light emitted by lighting sources  30  radiates onto the surfaces of fan impeller vanes  32  and into the interspaces  34  between fan impeller vanes  32 . To ensure uniform irradiation of the fan impeller with UV light inside receiving chamber  28 , which forms a section of air duct  18 , the lighting sources are arranged at intervals from one another on the circumferential surface of the receiving chamber surrounding fan impeller  22  on its outside. 
     In the embodiment shown here, receiving chamber  28  is substantially cylindrical in shape, and fan impeller  22  is arranged off-center in receiving chamber  28 . The air duct formed between the fan impeller and the outer side of the receiving chamber thus widens gradually in the direction of outlet  16 . The radial distance between lighting sources  30  and the outer circumferential surface of fan impeller  22  changes, therefore, which is why lighting sources  30  are arranged on the circumferential surface  35  of receiving chamber  28  at widening intervals from each other in the direction of outlet  16 . 
     The lighting sources are designed to emit light with a wavelength in the UV-C range from 100 nm to 280 nm, the lighting sources may be UV-C light emitting diodes. 
     In one embodiment, lighting sources  30  are arranged in electrical communication with each other on a flexible strip of material  36 . As shown by way of example in  FIG.  1   , the flexible strip of material  36  with inwardly facing lights  30  arranged thereon may be arranged between two housing portions  38 ,  38 ′ of housing  12 . In the embodiment shown in  FIG.  1   , the strip of material  36  seals the two housing portions  38 ,  38 ′ to each other. 
     In one embodiment, the treatment chamber inside the air duct has a material that reflects the light emitted from lights  30 , thus resulting in greater irradiation of the treatment chamber  26  of UV treatment unit  24 . Air blower apparatus  10  also includes a control unit  40  for controlling a drive means  42  that sets fan impeller  22  in rotational motion, in particular, and/or for controlling UV treatment unit  24 . Control unit  40  controls the switching ON and OFF of fan unit  20  and UV treatment unit  24 . The drive means  42  may be a motor. 
     In the present embodiment, control unit  40  is coupled in electrical communication with a detector  44  including at least one sensor for sensing at least the presence of an object approaching outlet  16  of air blower apparatus  10 . 
       FIG.  3    shows another embodiment of an air blower apparatus  10 ′ that includes a housing  12 ′. Housing  12 ′ has an inlet  14  and an outlet  16  and an air duct  18  extending inside housing  12 ′ between the inlet and the outlet. A fan unit  20  having the drive means  42  and a fan impeller  22  which can be set in rotational motion by the drive means is arranged in housing  12 ′. 
     Fan unit  20  is embodied for its part as a centrifugal fan. Air blower apparatus  10 ′ includes a control unit, not shown in further detail, which is supplied with electrical power via a power connection  45 . 
     Housing  12 ′ also includes two housing portions  38 ,  38 ′ which are connected sealingly to each other by a flexible strip of material  36 , on which, in the embodiment shown here, lighting sources  30  ( FIG.  4   ), embodied as UV-C diodes, are arranged in electrical communication with each other. As can be seen from the cross-sectional view in  FIG.  4   , fan unit  20  is arranged inside housing  12 , which forms a receiving chamber  28  for the fan unit and an air duct  18  for the air stream conducted from inlet  14  to outlet  16 . 
     In the embodiment shown here, a heating device  48  for heating the air stream  23  flowing through air duct  18  is provided in a section of the air duct. In one possible embodiment, a detector  44  having at least one sensor  46  is configured to sense at least the presence of an object approaching outlet  16  or associated with outlet  16  of air blower apparatus  10 ′. 
     Fan unit  20 , e.g., its drive means  42 , as well as heating device  50 , and/or UV treatment unit  24  are controlled by the control unit of air blower apparatus  10 ′, not shown here in further detail, if the presence of an object at outlet  16  is detected by the detector  44 . 
     The control units of air blower apparatuses  10 ,  10 ′ are configured to operate the air blower apparatus according to one or more of the following steps: driving fan impeller  22  and simultaneously actuating lighting sources  30  to produce the UV light for disinfecting the air stream  23  flowing through air duct  18 ; driving fan impeller  22  and simultaneously actuating lighting sources  30  to produce the UV light for disinfecting the air stream  23  flowing through the air duct  18  and actuating a heating device  50  for heating the air stream; driving fan impeller  22  and simultaneously actuating lighting sources  30  to produce the UV light for disinfecting the air stream flowing through air duct  18  and actuating a heating device  50  for heating air stream  23  for a specified period of time, wherein, after the specified period of time has elapsed, heating device  50  is switched OFF and fan impeller  22  is driven at a reduced speed with lighting sources  30  still switched ON, and actuating lighting sources  30  to produce the UV light for disinfecting the disinfecting fan impeller  22  when the fan impeller is stationary. 
     LIST OF REFERENCE SIGNS 
     
         
           10 ,  10 ′ Air blower apparatus 
           12 ,  12 ′ Housing 
           14  Inlet 
           16  Outlet 
           18  Air duct 
           20  Fan unit 
           22  Fan impeller 
           23  Air stream 
           24  UV treatment unit 
           26  Treatment chamber 
           28  Receiving chamber 
           30  Lighting source 
           32  Fan impeller vane 
           34  Interspace 
           35  Circumferential surface (receiving space) 
           36  Strips of material 
           38 ,  38 ′ Housing portion 
           40  Control unit 
           42  Drive means 
           45  Power connection 
           44  Detector 
           46  Sensor 
           48  Power connection 
           50  Heating device