Dryer for use in printing machine, has waste heat recovery system including air filter i.e. mechanical and/or chemical filter, and optical sensor device permanent or periodically monitoring air filter

摘要

The dryer has a waste heat recovery system (1) including a heat exchanger and/or a heat pump (2) that heat air. The waste heat recovery system includes an air filter (3.5) i.e. mechanical and/or chemical filter, and an optical sensor device permanent or periodically monitors the air filter, where degree of pollution of the air filter is determinable by the sensor device using differential pressure measurement. The sensor device outputs a signal during the determination of degree of pollution lying over a predetermined value. An independent claim is also included for a method for monitoring an air filter in a waste heat utilization system of a printing machine.