GB1424431A - Process and apparatus for drying porous material - Google Patents

Abstract

1424431 Microwave drying porous material KANEBO Ltd 19 March 1973 13013/73 Heading F4G Porous material is dried by an apparatus or a process wherein the material is charged into a closed drying chamber, drying air is blown on to the material and electromagnetic microwaves of very- or ultra-high frequency are directed on to the material. In Fig. 2, several porous articles 1 are hung inside the chamber, a motor driven fan 10 blowing air through a heat exchanger 11 and a punched plate or net 12 along the arrowed paths. A blower cooled magnetron oscillator 6 directs microwaves via a guide 7 into the chamber preferably at a later stage of. the drying process and has a drying capacity not more than that of the drying air. Fig. 3 shows porous material 17 fed continuously over rollers 21 through the chamber past drying air nozzles 20, microwaves being supplied at the exit end of the chamber as shown, or at the entrance end or at the middle thereof. A rotatable motor driven scattering plate 27, 28 at the entrance and exit prevent wave leakage. Intermittent movement of material through the chamber is provided in Fig. 5, a floor conveyer 41 carrying carriages 42a, 42b, 42c each carriage entering the chamber, then being moved forward successively to positions C, B, A and then leaving the chamber. Microwave radiation devices 45a, 45b, 45c have a plurality of openings 46a, 46b, 46c located in a distributor so that all of the material is exposed to the waves after the third position A. Each carriage has endless chains 97, Fig. 8, on either side driven by a motor via wheels 77, 86 to 96 and chains 85, and carrying hangers 98, 99 supporting articles 1 of the material the articles being continuously circulated inside the carriage during drying. The conveyer 41 is protected from microwave radiation by bottom plates in the carriages with shield plates extending downwardly therefrom. The conveyer 41 may be disposed in a gutter filled with water or other liquid to absorb the radiation. The material may be polyvinyl acetal, or polyvinyl formal.