GB401195A - Improvements in or relating to vacuum cleaners - Google Patents

Abstract

401,195. Vacuum cleaners. ELECTROLUX, Ltd., 153, Regent Street, London.- (Assignees of Inventia Patent- Verwertungs- Ges. ; 10, Herrenacker, Schaffhausen, Switzerland.) April 26, 1933, No. 12170. Convention date, May 7, 1932. [Class 8 (ii).] For indicating the filtering capacity of a dust separator for vacuum cleaners, a membrane is provided which is controlled by differences in pressure set up in an air stream passing through the cleaner due to variations in the filtering capacity of the dust separator and this co-operates with an indicator element. The vacuum cleaner 10 is divided into a lowpressure chamber 15 and a high-pressure chamber which includes the fan and its driving motor. The casing 10 has an opening 20 in which a sleeve element 21 is mounted which has a flange 22 hermetically retained against the casing and its inner end covered by a dished plate 23. A pocket-shaped membrane 24, preferably of rubber, is disposed inside the sleeve 21 and is kept in an extended position by means of a spring 26. The lower part of the membrane is open through the passage 30 to the space 15. Pressure of the spring may be adjusted by axial movement of the block 29. The membrane 24 contacts with a lever 32 which controls the semicylindrical rotatable element 33 disposed in a cover 34 having a window 35 through which its position may be observed. In an alternative form a disc 37, Fig. 5, is placed at the rear of the dust bag 39 and is carried by a partition plate 18 through a spring member 38 which under normal conditions is somewhat compressed. When the bag becomes clogged, the difference in pressure between the chamber 15 and chamber 39 is increased and the bag tends to regain its full length, so that the spring 38 is compressed and the screen 37 axially moved. The movement can be observed through a window 40 in the casing 10 of the cleaner. A pointer 41 may also be employed. In an alternative the dust bag 19 may be itself formed of a resilient or elastic material.