Kiln for baking ceramic prods. esp. tunnel kiln - where pulsed streams of cold air are injected in cooling zone of kiln to produce pronounced drop in temp. of baked prods.

摘要

The ceramic objects are stacked on a kiln car travelling through the kiln, and, after passing through the high temp. zone of the kiln, cold hair is injected to produce a sharp drop in temp. of the baked prods. The cold air is at high pressure, and is injected as a sequence of intermittent pulses. The cold air is pref. injected in pulses of 10 seconds duration sepd. by intervals of 20 seconds during which the air supply is choked or switched off, esp. via a timer operating a solenoid valve. The air is pref. injected via nozzle lances aligned diametrically opposite each other, esp. using two or four lances fed via air pipes contg. solenoid valves. The pulsed air cooling causing a sharp drop in temp. is applied uniformly to all the baked prods. so that the total kilm length can be reduced and the prods. have a uniform temp. near to room temp. when they leave the kiln.