The present invention relates to a method for provi- ding 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 descri- bed a device for feeding air to a treatment area in premi- ses. This device however, does not allow generation of a particular zone of clean air in the premises while simul- taneously feeding clean air to the remaining parts of said premises.

The object of the present invention has been to eli- minate 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 parti- cular 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 de- vice 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 emit- ting 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 de- vice 1 having a chassis 2 with driving wheels 3 for moving

the air treatment device 1 around on the floor 4 in pre- mises. A column 5 provided on the chassis 2 includes a ver- tical member 6 which at the top changes into a lateral mem- ber 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 lla, llb to give the intake air a desired degree of purity. In the air passage 10 there is provided, after the air clea- ning 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 10a, lOb. A first partial flow DS1 of the purified air RL is brought to flow through the passage branch 10a and a second partial flow DS2 of the purified air RL is brought to flow through the passage branch lOb. In the first passage branch 10a there is loca- ted a cooling device 13 for cooling the first partial flow DS1 and said passage branch 10a is provided to guide coo- led 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 lOb there is located a heating de- vice 14 for heating the second partial flow DS2 and the second passage branch lOb is provided to guide the heated air VL from the heating device 14 to at least one air dis- charge 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 sub- stantial 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 dischar- ges 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 dis- charge 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 DS1 to such temperature relative to the tem- perature 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 DS2 to such temperature relative to the tem- perature 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 premi- ses 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 schema- tically shown such a thermoelectric device with cooling members 13a and heat emitting or exothermal members 14a.

The cooling members 13a are in this case the cooling de-

vice 13 from which the cooled air KL is discharged and the heat emitting members 14a 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 loca- tion or point outside said zone.

The control device RC cooperates with a transmitter 21 which is situated in the air passage branch 10a down- stream 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 cont- rol 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 17a and a porous inner cell body layer 17b. The outer cell body layer 17a is preferably harder and has larger pores than the inner cell body layer 17b such that said outer cell body layer 17a defines a supporting part of the cell body mem- ber 17 and provides for a smaller fall of pressure for the passing processing air than the inner cell body layer 17b.

In the cell body member 17 there is preferably provi- ded 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 mem- ber 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 late- ral 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 DS1 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 down- stream of the air cleaning device 11. Thus, the degree of purity of the air in the zone of clean air RZ becomes sub- stantially 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 preferab- ly 100-300 m3/h and the air discharge unit 15 is preferab- ly 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 DS1 defi- ning 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 L1 closest to the ceiling and this upper air layer L1 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 L2 closest to the floor 4 and having a lower temperature than the upper air layer L1, and said lower air layer L2 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 L1 to the lower air layer L2 preferably through an intermediate air layer L3 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 de- vice 1. This results in that an air flow, free of turbu- lence, is generated when the purified air slowly descends in the premises. This effect intensifies the natural prin- ciple 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.