Drying unbaked ceramic prods. via current of hot air - esp. in tunnel dryer using co:current of hot air contg. large amt. of water vapour, so prods. do not crack during rapid drying

摘要

When the prods. are fed into a dryer, or directly thereafter, they are heated to 100 degrees C, while their moisture content is kept at the same value as that in the prods. at the commencement of heating. The prods. are pref. heated to 40-100 degrees C in a zone contg. a high partial vapour pressure due to water vapour, esp. via a stream of hot air at 120-400 degrees C, contg. 48-850 g moisture per kg of dry air. The hot air stream pref. travels in the same direction as the ceramic prods. through a tunnel dryer, i.e. from the dryer inlet; and part of the air stream is pref. recycled after reheating. Alternatively, the prods. can be heated to 40-100 degrees C in a water bath held at the required temp. Cf. prior art, the drying time can be reduced without causing microcracks and other defects in prods. such as bricks.