GB2357983A

GB2357983A - Dehumidifying apparatus

Info

Publication number: GB2357983A
Application number: GB9922560A
Authority: GB
Inventors: Tony Simpson
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-09-24
Filing date: 1999-09-24
Publication date: 2001-07-11
Anticipated expiration: 2019-09-24
Also published as: GB9922560D0; GB2357983B

Abstract

A dehumidifying apparatus comprises a desiccant 12 movable between an absorbing station and a heating station wherein the desiccant is regenerated by microwave radiation. Desiccant 12 is preferably mounted on a rotatable, sectioned, corrugated sheets 18 such that the sections rotate between an air drying station, a heating station and a blower 44 for drying the desiccant. Desiccant 12 may be contained in a cylindrical wheel by microwave impermeable plates and mesh 28A, 28B wherein a plate has a microwave input opening (42, fig. 4). Rotation of desiccant 12 may be controlled by an indexed induction drive motor 46 and sensors that detect the dampness of the desiccant and its alignment with the radiation source, namely a magnetron 38 and launcher 40. The apparatus is preferably sealed to prevent radiation leakage.

Description

2357983 D humid"g Anaratus The invention relates to a dehumidifying

apparatus and particularly to a rotary dehumidifying apparatus.

A conventional rotary dehumidifying apparatus includes a substantially cylindrical desiccant wheel, including a plurality of radially aligned, corrugated sheets impregnated with a desiccant. A fan drives air to be dried axially through the desiccant wheel such that moisture from the air is absorbed by the desiccant on the corrugated sheets. A second fan, spaced from the first, drives hot dry air through the desiccant wheel, to dry the desiccant on the corrugated sheets. The desiccant wheel rotates at a rate of about one revolution every six minutes such that any one portion of the desiccant wheel is brought into contact consecutively and repeatedly with moist air to be dried and with hot dry air for drying the desiccant. Once the hot air has passed through the desiccant wheel, it is expelled to the external atmosphere.

The above apparatus consumes relatively large amounts of energy. The hot air is heated to a temperature of about 80C to 1OWC and this hot air is generally expelled to the atmosphere once it has passed through the desiccant wheel.

According to the invention there is provided an apparatus including a desiccant for absorbing moisture and means for moving the 2 desiccant between an absorbing station and a heating station, wherein the apparatus includes means for providing microwave radiation to heat moisture in the desiccant when it is located in the heating station.

Preferably the apparatus includes fan means located near the absorbing station, for passing air to be dried over the desiccant when it is in the absorbing station.

Preferably the apparatus includes a rotatable member on which the desiccant is mounted. The rotatable member may include a plurality of desiccant members, whereby rotation of the rotatable member causes respective desiccant members to move consecutively and repeatedly into the absorbing station and the heating station.

Preferably the rotatable member is substantially cylindrical and is rotatable about a central axis. The desiccant members may be mounted for rotation about the central axis. The desiccant members may comprise radially oriented sheets impregnated with a desiccant material. The sheets may be corrugated. The sheets are preferably formed from a material substantially invisible to microwave radiation.

Preferably the rotatable member is separated into a plurality of discrete segments, each segment including boundaries through which substantially no microwave radiation may pass. The boundaries may include radially oriented 3 plates. Each segment may be bounded by two radially oriented plates, a substantially circumferential radially outer plate and a radially inner plate. The segment may be bounded at axially front and rear sides by a mesh of a material through which substantially no microwaves may pass. The mesh size is preferably less than Smm and most preferably less than 3mm. Preferably each segment contains a plurality of desiccant members. The rotatable member may be separated into between four and eight segments.

Preferably the means for providing microwave radiation includes means for heating moisture in all the desiccant members within a particular segment. Preferably the microwave radiation is provided within the segment, being contained within the segment by the plates and the mesh.

Preferably the means for providing microwave radiation includes a magnetron for providing microwaves within a segment.

Preferably the apparatus includes a duct which is substantially axially aligned with a segment when the segment is in the heating station. The duct may include two substantially radially oriented walls, a radially outer wall and a radially inner wall.

The magnetron may be located within or adjacent to the duct. A microwave launcher may be provided for directing microwaves from the magnetron to the segment. The launcher preferably allows substantially no 4 microwave radiation to pass back from the segment to the magnetron. The radially outer plate of the segment may be provided with a microwave input opening through which microwaves may pass into the segment.

Fan means may be provided for passing air through a segment when it is in the heating station.

The fan means may direct air through the duct into a segment located in the heating station. A further downstream duct may extend axially beyond the segment in a downstream direction. The downstream duct may be connected to a heat exchanger such that hot, moist air passing into the downstream duct may be used to heat the air to be passed into the upstream portion of the duct.

Alternatively or additionally fan means may be provided for passing air through a segment when it is in a blowing station spaced from the heating station. Preferably the blowing station is located such that rotation of the rotatable member causes a segment to move consecutively from the heating station to the blowing station.

Preferably seal means are provided for sealing junctions between a segment in the heating station and adjacent components. Preferably the seal means allow relative movement of the segment and the adjacent components.

Resilient seal means may be provided for containing the air flow. Such seal means may be provided between adjacent edges of the radially oriented walls of the duct and the radially oriented plates of the segments.

Microwave seal means may be provided for containing microwave radiation within a segment when it is in the drying position. The microwave seal means may include interlocking sets of conductive fingers, one set being provided on each component to be sealed. When in an interlocking position the respective fingers are preferably located less than Smm apart and most preferably less than 3mm apart. Such seal means may be provided at a junction between the microwave launcher and the microwave input opening in the radially outer plate of each segment. Such seal means may also or alternatively be provided between adjacent edges of the radially oriented walls of the duct and the radially oriented plates of the segments.

Alternatively or additionally microwave seal means in the form of a negative wave regenerative device may be provided.

The apparatus preferably includes sensor means for detecting when a segment is in the drying position. The sensor means may be operable to detect when a radially oriented plate of a segment is aligned with a radially oriented wall of the duct. A sensor means may be provided on each radially oriented plate. The sensor means may comprise a Hall effect sensor.

Means may be provided for indexing the rotatable member such that 6 each segment is rotated into the heating station, left in the heating station for a predetermined time and subsequently rotated out of the heating station, bringing an adjacent segment into the heating station. These means may include an indexing drive motor such as an induction stepper motor.

Means may be provided for signalling to the drive means that a segment is in the heating station. These means may include the sensor means. Means may also be provided for signalling to the magnetron that a segment is in the heating station.

According to the invention there is further provided a method of drying air using apparatus as previously defined, the method including the steps of: activating the fan means to pass air to be dried over a segment located in the absorbing station; activating the drive means to index a segment into the heating station; when the sensor means indicates that the segment is in the heating station, deactivating the drive means and activating the magnetron to pass microwave radiation into the segment; and after a predetermined time, deactivating the microwave and activating the drive means to bring an adjacent segment into the heating station.

The above steps are preferably carried out repeatedly and continuously.

The method may also include the step of passing air through the 7 segment located in the heating station. Alternatively the method may include the step of indexing the segment into a blowing station after the predetermined time, and passing air through the segment in the blowing station.

According to the invention there is also provided a method of drying air, the method including the steps of. passing air into contact with a desiccant in an absorbing station, such that the desiccant absorbs moisture from the air; moving the desiccant to a heating station; and providing microwave radiation within the heating station to heat moisture in the desiccant.

Preferably the desiccant is provided on a rotatable member and the method includes the step of rotating the member to move the desiccant consecutively and repeatedly between the absorbing station and the heating station.

Preferably the method further includes the step of conveying air to be dried through the absorbing station. The method may also include the step of conveying air through the heating station. Alternatively or additionally the method includes a further step of moving the desiccant to a blowing station and passing air through the blowing station.

Where the term "desiccant" is used in this specification, it does not necessarily refer to a commercially available desiccant, but to any substance or other means for absorbing moisture.

An embodiment of the invention will now be described for the purpose of illustration only with reference to the accompanying drawings, in which:Fig. 1 is a diagrammatic sectional view of a conventional dehumidifier; Fig. 2 is a diagrammatic sectional view of a dehumidifier according to a first embodiment of the invention; Fig. 3 is a diagrammatic perspective outline view of a desiccant wheel suitable for the dehumidifier of Fig. 2; Fig. 4 is a diagrammatic perspective outline view of an alternative desiccant wheel suitable for the dehumidifier of Fig. 2, illustrating some additional features of the apparatus; Fig. 5 is a diagrammatic side view of the desiccant wheel of Figs. 4; Figs. 6 and 7 are diagrammatic perspective views of a dehumidifier according to a second embodiment of the invention; Fig. 8 is a diagrammatic side view of the desiccant wheel of the 9 dehumidifier of Figs. 6 and 7; and Fig. 9 is a diagrammatic perspective view of the desiccant wheel of Figs. 6 and 7.

Referring to Fig. 1, a conventional dehumidifier 110 includes a generally cylindrical desiccant wheel 112 mounted for rotation about an axis 114.

The desiccant wheel includes a plurality of corrugated sheet members 118 impregnated with a desiccant substance such as silica gel, and mounted near the axis 114.

A fan 130 blows air to be dried through a lower portion of the desiccant wheel 112. The desiccant on the corrugated sheet members absorbs water from the air. A fan 144 blows hot, dry air through an upper portion of the desiccant wheel 12 as indicated by the arrows. This removes moisture from the desiccant in that portion of the wheel.

The desiccant wheel 112 is rotated by a drive motor 146, thus bringing a particular portion of the desiccant wheel consecutively into alignment with the fan 130 and the fan 144. The desiccant thus absorbs moisture from the air to be dried before having that moisture removed by the hot dry air blown by the fan 144.

The hot air which has passed through the upper part of the desiccant wheel 112 (and which is therefore moist) is generally expelled to the environment.

Referring to Figs. 2 to 5, a dehumidifier 10 according to a first embodiment of the invention includes a generally cylindrical desiccant wheel 12. The desiccant wheel is about lm in diameter and 0.5m in axial length and is mounted for rotation about an axis 14 on a bearing arrangement 16 (see Fig. 2).

The desiccant wheel 12 includes a plurality of generally conventional corrugated sheet members 18, of fibreglass or ceramic, mounted near the axis 14 of the desiccant wheel 12 and located in generally radial planes. Fig. 2 shows the corrugations on two sheet members 18 in dotted lines but the sheet members are not illustrated in the other drawings. Each sheet member 18 is impregnated with a desiccant substance such as silica gel.

Referring to Figs. 3 to 5, the desiccant wheel is divided into four discrete segments 20 by radial plates 22. The desiccant wheel may for example be divided into four segments see Fig. 3) or six segments (see Figs. 4 and 8). The radial plates 22 are of metal or another material through which substantially no microwave radiation may pass.

A. circumferential outer boundary of the desiccant wheel is encased in an outer member 24 which is also of metal or another material through which 11 microwaves do not pass. An inner plate 26 (see Fig. 5) of a similar material isolates each segment 20 from the central axis 14.

A?dally upstream and downstream sides of the desiccant wheel 12 are bounded by substantially circular mesh plates 28A and 28B respectively. The mesh plates consist of a metallic mesh having a mesh size of about 1Omm. or less. The function of the mesh plates 28A and 28B and of the radial and inner plates 22 and 26 and the outer member 24 is described in more detail hereinafter. A desiccant support material (not illustrated) is located under the mesh 28A/28B.

Referring to Fig. 2, a fan 30 is arranged to blow air through a lower portion of the desiccant wheel 12, as indicated by the lower arrow in Fig. 2. The air is forced between and over the corrugations in the corrugated sheet member 18 and moisture is thus removed from the air and absorbed by the desiccant. In this way, air in the room in which the dehumidifier is located may be dried.

Referring particularly to Fig. 4, an upstream duct 32A is located adjacent an upper part of the desiccant wheel 12. The duct 32A is of substantially the same sectional shape as a segment 20 of the desiccant wheel 12, having radially outer and radially inner walls 34A and 36A respectively. The duct 32A also includes radial walls 33A. A downstream duct 32B is of a generally similar shape, including corresponding radially outer and inner walls 34B and 36B and radial walls 33B.

12 Located above the upstream duct 32A is a magnetron 38, which is able to produce microwave radiation. A microwave launcher 40, in the form of a hollow duct, extends from the magnetron 38 to a microwave input slot 42 (see Fig. 4) provided in the outer member 24 of the desiccant wheel 12. Microwaves may be directed from the magnetron 38, through the launcher 40 and into an upper segment 20 of the desiccant wheel 12 when that segment is aligned with the duct 32. The launcher 40 is so designed that microwave radiation cannot pass in the reverse direction from the segment 20 back to the magnetron 38.

A fan 44 (see Fig. 2) is located upstream of the duct 32A and is arranged to blow air through the duct, into an upper segment 20 of the desiccant wheel 12 and subsequently through that segment into the downstream duct 32B. The air is able to pass through the mesh plates 28A into the segment 20 and through the mesh plates 28B out of the segment 20. Cooling fins 45 associated with the magnetron 38 utilise the cooling air to prevent the magnetron from overheating.

An indexing drive motor 46 such as an induction stepper motor, is located under and is drivingly connected to the desiccant wheel 12. The motor 46 is able to rotate the desiccant wheel 12 about its axis 14. The motor 46 rotates the desiccant wheel 12 in discrete steps, moving a first segment 20A into axial alignment with the duct 32A and leaving the segment in 20A in such a position for a predetermined time period, before moving a second segment 20B into alignment with the duct 32A (see Fig. 5).

13 As a segment 20A rotates into alignment with the duct 32A, the segment forms a cavity which is sealed to microwave radiation. The cavity is defined by the two radial plates 22 bounding the segment, the outer member 24 and the inner plate 26 along with the two mesh plates 28A and 28B. The mesh size of the mesh plates 28A, 28B is significantly less than the wavelength of the microwave radiation and thus microwave radiation cannot pass therethrough.

At a junction 48 between the radial plates 22 and the duct 32A and also at a junction (not shown in the drawings) between the radial plates 22 and the duct 32B, air seals and microwave shields may be provided. The seals (which are not illustrated in the drawings) allow relative rotation between the duct and the mesh plates, but seal the junction therebetween against air flow and microwave radiation. Sensors, which may be halleffect sensors, are provided for detecting when the radial plates 22 are in true axial alignment with the radially aligned edges of the duct 32.

The dehumidifier 10 works as follows. The fan 30 blows air through the desiccant wheel 12, particularly through a lower segment 20C. The air is forced between the corrugated sheet members 18 which are impregnated with desiccant and thus moisture is removed from the air. The desiccant wheel remains stationary in a particular position for perhaps one to two minutes. At the end of this time period, the motor 46 indexes the wheel around such that a segment, say segment 20B, moves into alignment with the duct 32A. The sensors detect such alignment and indicate that the motor should stop rotation 14 at this point. A signal is also sent to the magnetron which starts to produce microwave radiation. The microwave radiation is directed through the launcher 40 into the cavity formed by the segment 20B. The material of the corrugated sheet member 18 is substantially transparent to microwaves, and the microwave radiation is therefore substantially completely used in heating the moisture retained by the desiccant. This water is thus heated/boiled off the desiccant.

The fan 44 blows air through the cavity, thus removing the moisture laden air and transferring it into the downstream duct 32B. This moist, warm air is either expelled to the environment or transferred to a heat exchanger where it may be used to heat the air which is conveyed by the fan 44 into the segment 20B.

Once the segment 20B has been in alignment with the duct for about one to two minutes, a signal is sent to the magnetron to switch off the microwave radiation and to the motor to index the next segment 20C into alignment with the duct 32A. Once these sensors indicate that the segment 20C is truly in alignment with the duct 32A, a signal is sent to the magnetron which once more starts to produce microwaves. Thus the drying process is repeated for the segment 20C. The segment 20B will be rotated around and eventually into a position where it again absorbs moisture from the air directed by the fan 30.

In this way respective segments of the desiccant wheel are used to absorb is moisture and subsequently dried in turn.

Figs. 6 to 9 illustrate an alternative embodiment of the invention, in which corresponding elements are given corresponding reference numerals.

In the embodiment of Figs. 6 to 9, microwaves enter a segment 20A axially rather than radially. The sheet members 18 of the segment 20A are heated within the heating cavity, by the microwaves, before being indexed to a purging station where the damp air is blown out of the segment 20A.

Referring to Figs. 6 and 9, a pair of magnetrons 38 are located within an enclosed duct 32C. When a segment 20A is positioned at a heating station 60 axially aligned with the duct 32C, microwaves may enter the segment 20A and heat the desiccant therein. Because the duct 32C is sealed, no mesh is required around the segment 20A. However air seals and microwave seals 62 are provided at the boundaries of the heating station 60. The microwave seals may include negative wave regenerative devices, for using negative interference to ticancel ouC microwaves. A rim 68 of the desiccant wheel is extended, for engaging with the seals.

Adjacent to the enclosed cavity 32C is an open ended duct 32A, located axially upstream and adjacent to a purging station 64. A fan (not shown) is operable to blow air through the duct 32A into a segment 20 located in the purging station 64. Air leaving the segment 20 located in the purging station 16 64 passes into a downstream duct 32B. The air may pass to a heat exchanger for heating air to pass through the purging station 64.

Cooling fins 66 of the magnetrons 38 extend into the duct 32A, to utilise the cooling effect of the air flow.

The dehumidifier 10 functions in a similar manner to the previous embodiment, except that microwaves enter the heating station 60 axially. Further, no air flows through the heating station 60. Instead, a separate purging station 64 is provided, for drying the desiccant heated in the heating station 60. After a segment 20A has been heated in the heating station 60, it is indexed to the purging station 64, for drying, before being indexed around to an absorbing station 66.

This embodiment has the advantage that very little heat is lost with the purged air, and mesh is not required on the desiccant wheel.

There is thus provided a dehumidifier in which the drying of the desiccant material is carried out with great efficiency. It is estimated that a dehumidifier according to a preferred embodiment of the invention may use as little as one tenth of the energy used by a prior art dehumidifier.

Various modifications may be made to the above described embodiment without departing from the scope of the invention. In particular, the position 17 of the magnetron and the shapes and positions of the various other components may be altered.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

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Claims

1. Apparatus including a desiccant for absorbing moisture and means for moving the desiccant between an absorbing station and a heating station, wherein the apparatus includes means for providing microwave radiation to heat moisture in the desiccant when it is located in the heating station.

2. Apparatus according to claim 1, wherein the apparatus includes fan means located near the absorbing station, for passing air to be dried over the desiccant when it is in the absorbing station.

3. Apparatus according to claim 1 or claim 2, wherein the apparatus includes a rotatable member on which the desiccant is mounted.

4. Apparatus according to claim 3, wherein the rotatable member includes a plurality of desiccant members, whereby rotation of the rotatable member causes respective desiccant members to move consecutively and repeatedly into the absorbing station and the heating station.

5. Apparatus according to claim 3 or claim 4, wherein the rotatable member is substantially cylindrical and is rotatable about a central axis.

6. Apparatus according to claim 5, wherein the desiccant members are mounted for rotation about the central axis.

7. Apparatus according to claim 6, wherein the desiccant members comprise radially oriented sheets impregnated with a desiccant material.

8. Apparatus according to claim 7, wherein the sheets are corrugated.

9. Apparatus according to claim 7 or claim 8, wherein the sheets are formed from a material substantially invisible to microwave radiation.

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10. Apparatus according to any of claims 3 to 9, wherein the rotatable member is separated into a plurality of discrete segments, each segment including boundaries through which substantially no microwave radiation may pass.

11. Apparatus according to claim 10, wherein the boundaries include radially oriented plates.

12. Apparatus according to claim 11, wherein each segment is bounded by two radially oriented plates, a substantially circumferential radially outer plate and a radially inner plate.

13. Apparatus according to any of claims 10 to 12, wherein each segment is bounded at a3dally front and rear sides by a mesh of a material through which substantially no microwaves may pass.

14. Apparatus according to claim 13, wherein the mesh size is less than 5mm.

15. Apparatus according to claim 14, wherein the mesh size is less than 3nun.

16. Apparatus according to any of claims 10 to 15, wherein each segment contains a plurality of desiccant members.

17. Apparatus according to any of claims 10 to 16, wherein the rotatable member is separated into between four and eight segments.

18. Apparatus according to any of claims 10 to 17, wherein the means for providing microwave radiation includes means for heating moisture in all the desiccant members within a particular segment.

19. Apparatus according to claim 18, wherein the microwave radiation is provided within the segment, being contained. within the segment by the plates and mesh.

20. Apparatus according to claim 18 or claim 19, wherein the means for providing microwave radiation includes a magnetron for providing microwaves within a segment.

21. Apparatus according to any of claims 10 to 20, wherein the apparatus includes a duct which is substantially a3dally aligned with a segment when the segment is in the heating station.

22. Apparatus according to claim 21, wherein the duct includes two substantially radially oriented walls, a radially outer wall and a radially inner waU.

23. Apparatus according to claim 21 or claim 22, wherein the magnetron is located within or adjacent to the duct.

24. Apparatus according to claim 23, wherein a microwave launcher is provided for directing microwaves from the magnetron to the segment.

25. Apparatus according to claim 24, wherein the launcher allows substantially no microwave radiation to pass back from the segment to the magnetron.

26. Apparatus according to any of claims 12 to 25, wherein the radially outer plate of the segment is provided with a microwave input opening through which microwaves may pass into the segment.

27. Apparatus according to any of claims 10 to 26, wherein fan means is provided for passing air through a segment when it is in the heating station.

28. Apparatus according to claim 27, wherein the fan means directs air 21 through the duct into a segment located in the heating station.

29. Apparatus according to claim 2 1, wherein a further downstream duct extends axially beyond the segment in a downstream direction.

30. Apparatus according to claim 29, wherein the downstream duct is connected to a heat exchanger such that hot, moist air passing into the downstream duct is used to heat the air to be passed into the upstream portion of the duct.

31. Apparatus according to any of claims 10 to 30, wherein fan means is provided for passing air through a segment when it is in a blowing station spaced from the heating station.

32. Apparatus according to claim 31, wherein the blowing station is located such that rotation of the rotatable member causes a segment to move consecutively from the heating station to the blowing station.

33. Apparatus according to any of claims 10 to 32, wherein seal means are provided for sealing junctions between a segment in the heating station and adjacent components.

34. Apparatus according to claim 33, wherein the seal means allow relative movement of the segment and the adjacent components.

35. Apparatus according to claim 33 or claim 34, wherein resilient seal means are provided for containing the air flow.

36. Apparatus according to claim 35, wherein said seal means are provided between adjacent edges of the radially oriented walls of the duct and the radially oriented plates of the segments.

37. Apparatus according to any of claims 10 to 36, wherein microwave seal 22 means are provided for containing microwave radiation within a segment when it is in the drying position.

38. Apparatus according to claim 37, wherein the microwave seal means includes interlocking sets of conductive fingers, one set being provided on each component to be sealed.

39. Apparatus according to claim 38, wherein when in an interlocking position the respective fingers are located less than Smm apart.

40. Apparatus according to claim 39, wherein when in the interlocking position the respective fingers are located less than 3mm apart.

41. Apparatus according to any of claims 37 to 40, wherein the seal means are provided at a junction between the microwave launcher and the microwave input opening in the radially outer plate of each segment.

42. Apparatus according to any of claims 37 to 41 when appended to claim 22, wherein the seal means are provided between adjacent edges of the radially oriented walls of the duct and the radially oriented plates of the segments.

43. Apparatus according to any of claims 37 to 42, wherein microwave seal means in the form of a negative wave regenerative device are provided.

44. Apparatus according to any of claims 10 to 43, wherein the apparatus includes sensor means for detecting when a segment is in the drying position.

45. Apparatus according to claim 44, wherein the sensor means is operable to detect when a radially oriented plate of a segment is aligned with a radially oriented wall of the duct.

46. Apparatus according to claim 45, wherein a sensor means is provided on each radially oriented plate.

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47. Apparatus according to any of claims 44 to 46, wherein the sensor means comprises a Hall effect sensor.

48. Apparatus according to any of claims 10 to 47, wherein means are provided for indexing the rotatable member such that each segment is rotated into the heating station, left in the heating station for a predetermined time and subsequently rotated out of the heating station, bringing an adjacent segment into the heating station.

49. Apparatus according to claim 48, wherein indexing means include an indexing drive motor such as an induction stepper motor.

50. Apparatus according to claim 49, wherein means are provided for signalling to the drive means that a segment is in the heating station.

51. Apparatus according to claim 50, wherein the signalling means include the sensor means.

52. Apparatus according to any of claims 48 to 5 1, wherein means are also provided for signalling to the magnetron that a segment is in the heating station.

53. A method of drying air using apparatus according to claim 5 2, the method including the steps of:

activating the fan means to pass air to be dried over a segment located in the absorbing station; activating the drive means to index a segment into the heating station; when the sensor means indicates that the segment is in the heating station, deactivating the drive means and activating the magnetron to pass microwave radiation into the segment; and 24 after a predetermined time, deactivating the microwave and activating the drive means to bring an adjacent segment into the heating station.

54. A method according to claim 53, wherein the steps are carried out repeatedly and continuously.

55. A method according to claim 53 or claim 54, wherein the method also includes the step of passing air through the segment located in the heating station.

56. A method according to any of claims 53 to 55 wherein the method includes the step of indexing the segment into a blowing station after the predetermined time, and passing air through the segment in the blowing station.

57. A method of drying air, the method including the steps of:

passing air into contact with a desiccant in an absorbing station, such that the desiccant absorbs moisture from the air; moving the desiccant to a heating station; and providing microwave radiation within the heating station to heat moisture in the desiccant.

58. A method according to claim 57, wherein the desiccant is provided on a rotatable member and the method includes the step of rotating the member to move the desiccant consecutively and repeatedly between the absorbing station and the heating station.

59. A method according to claim 5 7 or claim 5 8, wherein the method further includes the step of conveying air to be dried through the absorbing station.

60. A method according to any of claims 57 to 59, wherein the method also includes the step of conveying air through the heating station.

61. A method according to any of claims 5 7 to 60, wherein the method includes a further step of moving the desiccant to a blowing station and passing air through the blowing station.

62. Apparatus substantially as herein described with reference to the drawings.

63. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.