In-room hydroponic air cleansing unit

1. A hydroponic air-cleansing unit, wherein:

the unit is structured for placement in a room in a building, and for cleansing the air in the room;

the unit includes media-material, which is disposed in a vertical hydroponic configuration, in that the media-material:

(a) is of sheet-form, being of large area and small thickness;

(b) is disposed as a substantially-vertical sheet;

(c) is configured to form a wall of a media-cylinder;

(d) is porous, and is permeable to throughflow of air and throughflow of water;

(e) is of such nature that roots of plants can be embedded in the media-material, whereupon the media-material provides mechanical support for the plants;

the unit includes a powered water-pump, which feeds hydroponic water into the top of the media-cylinder, whereby the water passes down through the media-material, and wets the roots of plants embedded in the media-material;

the unit includes a powered air-pump or fan, which forces room-air to permeate radially through the media-material, and to pass over the roots of the plants embedded in the media-material;

the wall of the media-cylinder defines a hollow interior vault between said media cylinder and a fixed frame, positioned centrally;

the unit includes an upper-vault seal and a lower-vault seal;

the seals are effective to seal the vault in such manner that air cannot move between the room and the vault except by passing through the media-material;

the unit includes a rotary-frame;

the rotary-frame is mounted for rotation with respect to the fixed-frame;

the rotation is about a vertical axis;

the media-cylinder is fixed to the rotary-frame, such that the media-cylinder is rotatable in unison with the rotary-frame;

the rotary-frame, the media-cylinder, and plants embedded in the media-material, are integrated components of a rotary-assembly;

the structure of the unit, and the manner of rotation, are such that, when plants are embedded in the media-cylinder, and when the unit is placed in a room having a point source of light, the plants can be exposed equally to that source.

2. A hydroponic air-cleansing unit as claimed in claim 1 , wherein the unit includes a central tube, which:

defines a hollow interior cavity, connected by air-conduits to the powered air-pump.

3. A hydroponic air-cleansing unit as claimed in claim 2 , wherein the central tube has apertures, through which air can move between the vault and the cavity.

4. A hydroponic air-cleansing unit as claimed in claim 3 , wherein the central tube is a fixed component of the fixed frame.

5. A hydroponic air-cleansing unit as claimed in claim 4 , wherein:

the unit includes a thrust-bearing that acts between the rotary-frame and the central tube;

the unit is so arranged that the thrust bearing transfers the weight of the rotary-assembly directly to the central tube.

6. A hydroponic air-cleansing unit as claimed in claim 3 , wherein:

the upper-vault-seal seals the media-cylinder with respect to the fixed-frame;

the fixed-frame includes a rotary-roof-component of the rotary-frame, which overlies the media-cylinder;

the upper-vault-seal seals the roof-component with respect to the central-tube;

the rotary roof-component of the rotary-frame is formed with a channel;

the media-material that forms the wall of the media-cylinder is:

(a) located in the channel; and

(b) is sealed with respect to the channel by being a tight fit in the channel.

7. A hydroponic air-cleansing unit as claimed in claim 3 , wherein:

the central tube has a vertical axis and includes rotary bearings, upon which the rotary-frame is mechanically supported for rotation.

8. A hydroponic air-cleansing unit as claimed in claim 3 , wherein:

the apertures in the central tube comprise many small air-holes through the wall of the central tube;

the air-holes are arranged in a regular pattern, arranged for evenness of radial airflow through all sectors of the vault;

the size of the air-holes is such that the pressure drop through the holes, as air passes between the vault and the cavity, is at least eight mm of water.

9. A hydroponic air-cleansing unit as claimed in claim 1 , wherein:

the upper-vault-seal seals the media-cylinder with respect to the fixed-frame;

the fixed-frame includes a fixed-roof-component of the fixed-frame, which overlies the media-cylinder;

the upper-vault-seal is comprised in that an elastomeric seal:

(a) is fixed with respect to the rotary frame;

(b) is sealed with respect to the media-cylinder;

(c) makes rubbing sealing contact with respect to the roof-component.

10. A hydroponic air-cleansing unit as claimed in claim 1 , wherein:

the unit includes water nozzles, which are positioned for delivering hydroponic water from the water-pump down on top of the media-material of the wall of the media-cylinder, evenly around the circumference of the media-cylinder;

the unit includes a water conduit for conveying hydroponic water from the water-pump to the nozzles;

the water-pump is set so that the water, immediately prior to passing through the nozzles, is at a pressure head of at least ten cm;

the water-pump is a component of the fixed frame; and either

(a) the water nozzles are integral a rotary roof component of the rotary frame, and the water conduit includes a fixed-conduit and rotary-conduit, and includes a sealed rotary joint between the two; or

(b) the water nozzles are integral with a fixed roof component of the fixed-frame.

11. A hydroponic air-cleansing unit as claimed in claim 1 , wherein the plants form a continuous circumference over the outer surface of the media-cylinder, substantially without gaps.

12. A hydroponic air-cleansing unit as claimed in claim 1 , wherein:

the media-material has a water-holding capacity of 0.02 to 0.1 grams of water per cc of the material;

the media material has an air-permeability such that the pressure head drop that is needed in order to create a velocity of air through the media-material of twenty cm/sec is between two millimeters and ten mm of water.

13. A hydroponic air-cleansing unit as claimed in claim 1 , wherein:

the rotary-frame includes a hub, spokes, and upright bars;

the unit includes fixing bolts that pass through the media material and though holes in the bars, whereby the wall of the media-cylinder is fixed to the bars;

the hub is a loose fit on the fixed tube, and a rotary journal bearing is formed between the tube and the rotary-frame, by the fit of the hub to the tube.

14. A hydroponic air-cleansing unit as claimed in claim 1 , wherein the wall of the media-cylinder comprises two sheets of the media-material, configured as two cylinders, one inside, and in contact with, the other.

15. A hydroponic air-cleansing unit as claimed in claim 1 , wherein the air-pump or fan drives the air in the radially-inwards direction with respect to the vault.

16. A hydroponic air-cleansing unit as claimed in claim 1 , wherein:

the unit includes a rotation-motor, which drives the media-cylinder to rotate;

the media-cylinder is driven to rotate at a speed of between five and forty-eight revolutions per day.

17. A hydroponic air-cleansing unit as claimed in claim 1 , wherein the media-material is inert with respect to plants and hydroponic water.

18. A hydroponic air-cleansing unit as claimed in claim 1 in combination with a room, wherein a point-source of light is a window of the room.

19. A hydroponic air-cleansing unit as claimed in claim 1 , wherein:

the lower-vault-seal seals the media-cylinder with respect to the fixed-frame;

the fixed-frame includes a water collecting basin;

the basin is located underneath the media-cylinder;

the lower-vault-seal is comprised in that the unit is structured to maintain a level of water in the basin, and the media-cylinder is sealed at the bottom by dipping in the water in the basin;

thereby preventing air from moving between the room and the vault by passing underneath the media-cylinder.