Volume flow monitoring system for filtering devices

摘要

It is known that filtering devices are gradually obstructed by dust and other harmful substances and the volume flow acting on them is constantly reduced. Monitoring the volume flow for pressure losses is very expensive. According to the invention, it is therefore proposed to place two thermistors (1, 2) in a comparison bridge circuit in the drawing-in or blowing-out region of the device air flow. The thermistors (1, 2) are heated via an outside flow, one thermistor (1) being situated in the air flow and the other in the still air. As a result of the different degree of cooling, a bridge voltage is generated which gives information on the state of the filter as a signal and/or display. <IMAGE>