Composite filter unit with electric heating element - which has heating mat mounted between frame and gas adsorption filter

摘要

Heating device for composite filter units uses an electrical heating mat with a surrounding frame which is mounted between the outer frame and the gas filter. The mat is held by its frame against the outer frame. The surrounding frame is made from a flexible heat resistant material. It can also have a drawn down surrounding edge. For use in filtering air and other gases to remove dust and other harmful components. This is done in two stages a dust filter and a gas filter. The first is generally a woven cloth element and the other an activated carbon filter. The efficiency of these is affected by the relative humidity of the feed gas. This can be reduced by warming the air. However if the heater is in front of the fabric filter it becomes fouled up. The system avoids fouling of the fabric filter but allows maintenance of the heater after use.