Patent Publication Number: US-6702662-B2

Title: Method for providing clean air in premises and device for carrying through said method

Description:
The present invention relates to a method for providing clean or pure air in premises, wherein unclean or impure air is received in an air-treatment device from lower portions of the premises and cleaned or purified therein. The invention further relates to a device for carrying through said method. 
     In the publication SE, C2, 500 707 there is described a device for feeding air to a treatment area in premises. This device however, does not allow generation of a particular zone of clean air in the premises while simultaneously feeding clean air to the remaining parts of said premises. 
     The object of the present invention has been to eliminate this problem and this is done by providing the method according to the invention with the characterizing measures of subsequent claim 1. 
     A device for carrying through said method is given the characterizing features of subsequent claim 22. 
     By means of the method and device according to the invention, it is possible to generate at least one particular zone of clean air in the premises while at the same time providing the rest of the premises with clean air. 
    
    
     The invention will be further described below with reference to the accompanying drawings, in which 
     FIG. 1 schematically illustrates premises with a device according to the invention; 
     FIG. 2 is a side view, partly in section, of a device according to the invention; 
     FIG. 3 is a section of an air discharge or air emitting unit forming part of the device of FIG. 1; and 
     FIG. 4 schematically illustrates a cooling device forming part of the device of FIG.  1 . 
    
    
     In FIG. 1 there is illustrated an air treatment device  1  having a chassis  2  with driving wheels  3  for moving the air treatment device  1  around on the floor  4  in premises. A column  5  provided on the chassis  2  includes a vertical member  6  which at the top changes into a lateral member  7 . The vertical member  6  has down below two air intake openings  8 ,  9  for inlet of impure air OR from floor level in the premises into an air passage  10  in the column  5 . 
     In the air passage  10  there is located, closest to the air intake openings  8 ,  9 , an air cleaning or purifying device  11  of a suitable type, e.g. two filter devices  11   a ,  11   b  to give the intake air a desired degree of purity. In the air passage  10  there is provided, after the air cleaning device  11 , a fan device  12  for sucking air into and bring it flow through the air passage  10  and further through the air treatment device  1 . 
     The air passage  10  is divided into at least a first and a second passage branch  10   a ,  10   b . A first partial flow DS 1  of the purified air RL is brought to flow through the passage branch  10   a  and a second partial flow DS 2  of the purified air RL is brought to flow through the passage branch  10   b . In the first passage branch  10   a  there is located a cooling device  13  for cooling the first partial flow DS 1  and said passage branch  10   a  is provided to guide cooled air KL to at least one air discharge unit  15  which is located on the underside of the lateral member  7 . In the second passage branch  10   b  there is located a heating device  14  for heating the second partial flow DS 2  and the second passage branch  10   b  is provided to guide the heated air VL from the heating device  14  to at least one air discharge opening  16  or corresponding means for the discharge of heated air VL. 
     As is apparent from FIGS. 1 and 2, the air discharge unit  15  and the air discharge opening  16  are provided on opposite parts of the air treatment device  1  and at substantial distance from each other, namely such that the cooled and the heated air flow out into different parts of the premises. Thus, the air discharge unit  15  discharges cooled air KL to generate at least one zone of clean or pure air RZ beneath said air discharge unit  15  on one side of the air treatment device  1 , while the air discharge opening  16  is provided on an opposite side of the air treatment device  1  such that it discharges heated air VL in a direction upwards towards the ceiling region TR in the premises at a substantial distance from the clean air zone RZ. 
     The cooling device  13  is provided to cool the first partial flow DS 1  to such temperature relative to the temperature of the air in the premises where the cooled air KL shall be discharged, that said cooled air KL will sink slowly, through a cell body member  17  forming part of the air discharge unit  15 , for generating the zone of clean air RZ without thereby substantially co-eject impure air from the surroundings into the zone of clean air RZ and preferably without generating substantial turbulence in the air in the premises. 
     The heating device  14  is provided to heat the second partial flow DS 2  to such temperature relative to the temperature of the air in the premises where the heated air VL shall be discharged, that said heated air VL slowly rises upwards towards the ceiling region TR of the premises without thereby causing substantial turbulence in the air in said premises. 
     The zone of clean or pure air RZ may constitute or define parts of a breathing zone A for a person  18  which e.g. lies on a bed  19  or similar, but said zone of clean air RZ may also be another zone where clean air is needed, e.g. a working zone wherein work is done. 
     The cooling device  13  may be a thermoelectric device with Peltier-effect, i.e. an effect which is generated when an electric current is sent through two metals which are in contact with each other. In the contact surface, cooling is thereby obtained. In FIG. 3, there is schematically shown such a thermoelectric device with cooling members  13   a  and heat emitting or exothermal members  14   a . The cooling members  13   a  are in this case the cooling device  13  from which the cooled air KL is discharged and the heat emitting members  14   a  are defined by the heating device  14  from which the heated air VL is discharged. 
     The cooling device  13  may be controlled by a control device RC which cooperates with a transmitter  20  which is situated on the same or substantially the same level as the breathing zone A or similar and preferably at a location or point outside said zone. 
     The control device RC cooperates with a transmitter  21  which is situated in the air passage branch  10   a  downstream of the cooling device  13 . The transmitter  21  is adapted to measure the temperature at said level and, based on the measurement result, transmit a signal to the control device RC. The control device is adapted to control the cooling device  13  based on the temperature at said level. The transmitter  21  is preferably a set point transmitter which is set or adjusted to a certain set point temperature for the processing air. 
     The fan device  12  is adapted to bring the processing air to flow through the air treatment device  1  such that the air flow overcomes the resistances therein, but not such that the air flow is pressed or forced out through the air discharge unit  15 . Hereby, it is guaranteed that the air discharged from the air discharge unit  15  does not become substantially turbulent and does not co-eject impure air from the surroundings. 
     The cell body member  17  of the air discharge unit  15  preferably has a porous outer cell body layer  17   a  and a porous inner cell body layer  17   b . The outer cell body layer  17   a  is preferably harder and has larger pores than the inner cell body layer  17   b  such that said outer cell body layer  17   a  defines a supporting part of the cell body member  17  and provides for a smaller fall of pressure for the passing processing air than the inner cell body layer  17   b.    
     In the cell body member  17  there is preferably provided an air guide means  22  which, relative to the incoming flow of processing air, has a transverse member and which is vertically adjustable relative to the cell body member  17 . This air guide means  22  is adapted to guide the air flowing into the cell body member  17  relative to the various portions of said cell body member  17 . 
     The air discharge unit  15  may be mounted on the lateral member  7  of the column  5  by means of a bayonet fixing (not shown) or by means of another coupling device. 
     The device described above operates as follows: 
     The first partial flow DS 1  is cooled in the cooling device  13  to a temperature which is lower, e.g. 1-3° C. lower than the temperature measured by the transmitter  20  in level with the breathing zone A or similar, and is brought to flow through the cell body member  17  of the air discharge unit  15  in such a way that the rate of fall of the cooled air KL becomes low. This cooled air KL gets such an extension or spreading that an outer zone RZY does not substantially co-eject impure air and prevents thereby impure air from being mixed with the clean air zone RZ and particularly with a central part RZZ thereof. Hereby, air in said central part RZZ of the clean air zone RZ can be brought to have substantially the same degree of purity as the clean air RL immediately after or downstream of the air cleaning device  11 . Thus, the degree of purity of the air in the zone of clean air RZ becomes substantially the same as immediately after the air cleaning or air purifying device  11  despite the air is brought to flow through impure air in the premises. 
     The air flow in the zone of clean air RZ is preferably 100-300 m 3 /h and the air discharge unit  15  is preferably located at a height of 0,5-1,5 m above the breathing zone A or similar. The cell body member  17  of the air discharge unit  15  is preferably designed such that it discharges or emits air consisting of laminar partial air flows. Moisture and/or gaseous medicine may when needed be added to the air in the first partial flow DS 1  defining the clean air zone RZ. 
     It should also be mentioned that the heated air VL is brought to flow upwards such that it forms an upper layer of air L 1  closest to the ceiling and this upper air layer L 1  is brought to keep a temperature of preferably about 22° C. At the same time, air is sucked into the air treatment device  1  from a lower layer of air L 2  closest to the floor  4  and having a lower temperature than the upper air layer L 1 , and said lower air layer L 2  preferably has a temperature of about 20° C. 
     Air is brought to fall or descend at low speed and without turbulence from the upper air layer L 1  to the lower air layer L 2  preferably through an intermediate air layer L 3  which might have a temperature of about 21° C. 
     Hereby, one can utilize a controlled zoning present in the premises for spreading the warm (“lighter”) air along the ceiling and at the same time suck the cooler/impure air from floor level into the air treatment device  1 . This results in that an air flow, free of turbulence, is generated when the purified air slowly descends in the premises. This effect intensifies the natural principle of sedimentation at which particles in the premises slowly fall or descend towards floor level provided that said premises lack turbulence-generating devices, e.g. air-mixing air supply units or similar. 
     The method described above and the device described above may vary within the scope of subsequent claims. An alternative embodiment not described above might include that the air purifying device  11  can purify air in another way than by filtration and the air therein may be treated with radiation or ionized or provided with moisture and/or medicine. About half the air taken in into the air treatment device  1  is discharged or emitted as cooled air KL and about half as heated air VL. The cooling device  13  may be another cooling device than a thermoelectric device. The air discharge unit  15  may have another form than the one described and shown and it may include one or more cell body members  17  and/or cell body layers. There may also be more than one air discharge unit  15 . The breathing zone A or similar may be another area wherein clean air is needed and instead of air or in connection therewith, a protective gas may be used.