| 摘要 |
1,192,320. Microwave heating. BECHTEL INTERNATIONAL CORP. 2 Dec., 1968 [6 Dec., 1967], No. 57151/68. Heading H5H. [Also in Division F4] A split waveguide through which a web 7 to be dried is passed in the direction of the arrow has a pair of plates 23 of lossy R.F. material positioned between the waveguide halves 9 and 11, the plates 23 being positioned on either side of the axial slot formed between the halves 9 and 11 and extending the length of the slot to prevent leakage therefrom. Further "lossy" plates 41, 43 are provided at the entry and exit to the slot to minimize leakage from these points. Suitable lossy materials are mixtures of iron particles and carbon, carborundum, or ceramics. The plates 23 have wedge shaped projections 25 to enhance R.F. absorption. Plates 23, 41, and 43 are slotted longitudinally to accommodate rubber or plastic cooling tubes such as 45 through which cooling fluid may pass. The fluid may also absorb R.F. energy. A pair of cooling tubes in each plate 23 makes an air-tight seal with the wall 39 of the adjacent waveguide half 11. Each plate 23 may be replaced by two plates of lossy maserial which are fixed to the individual halves 9, 11 of the waveguide. Drying gas e.g. air is supplied to the waveguides from inlet plenums 15 and moist gas is exhausted through outlet plenums 21. Fluttering of the moving web 7 at the input and exit ends of the waveguide is prevented by supplying high pressure gas to both sides of the web through holes 47 in the lossy plates 41, 43, from inlet plenums 15. The waveguide is of meander form. The halves of the waveguide may be wholly or partly covered with plastics. |
