Device for detection of degree of clogging of a dust filter

Abstract

A device for providing a signal warning of a clogging of a dust filter. A pair of air flow speed sensors A and B are arranged downstream of two sections of a dust filter 1 arranged in an air duct 1, and the outputs of the sensors A and B are connected to a comparator 6 having an output connected to a warning device 7. An obstacle 3 is arranged upstream or downstream of one section of the filter 1. When the filter is new, the speed of the air flow detected by the sensor B without an obstacle is higher than that detected by the sensor A located downstream of the obstacle, but the speed of clogging at the section without an obstacle is much higher than that at the section located downstream of the obstacle, and thus, after continuous use, the air speed detected by the sensor B becomes equal to that detected by the sensor A. The values of the detected speeds are compared to determine a degree of clogging of the filter, and to issue a warning signal when needed.

Dependencies are inferred from the claim text.