GB278927A - - Google Patents

Abstract

278,927. Deutsche Ga,sgluhlicht-Auer- Ges., Wollin, K., and Smolczyk, E. Jan. 17, 1927. Addition to 254,299. Respirators. - Indicating or controlling devices applicable to air filters and operating in the presence of impurities or other additions in gases as in the parent Specification are provided with means operating at a definite temperature or change of temperature. Two test substances, one crumbling, without fusing, in the presence of the impurity and the other fusing at a definite temperature, or a single substance having both properties may be used. In an arrangement for actuating a signal at a definite moisture content of the air and also at a definite temperature, a spring-loaded pin bears against a test tablet which collapses on exposure to moisture and certain parts such as the pin or the supports of the tablet are of Wood's metal or other material fusing at the required temperature. In an air filter, a valve-plate c is pressed towards an opening d in a partition b by a spring g and is held away from the opening by a pin e guided in a cap h and pressing against a test tablet f supported by pins i. The valve closes either in the presence of impurity in the air or at a definite temperature, the tablet f crumbling in the former case and the pins i fusing in the latter case.