GB438366A - Improvements in or connected with desiccating apparatus - Google Patents

Abstract

438,366. Drying air. BARR & STROUD, Ltd., and FRENCH, J. W., Caxton Street, Anniesland, Glasgow. May 14, 1934, No. 14473. [Class 34 (i)] Desiccating-apparatus particularly for use in optical instruments is characterized in that there is interposed between the desiccating material and the exterior of the apparatus, a filtering medium consisting of fibrous or like material, e.g. glass wool or cotton wool, which permits the passage of air but not that of dust. As shown in Fig. 1, the desiccating material B, e.g. silica gel, is disposed in a container A which comprises a transparent cylindrical window 2 to enable the gel to be observed, the window 2 being fastened to cylindrical extensions of annular plates 3, 4, which have central openings covered by metal gauze sheets 5, 6. The filtering medium D is retained in position by means of perforated covers 7 and spring rings 8. The silica gel is arranged to cover the central openings in the plates 3, 4, so that air cannot pass through the apparatus without traversing some of the silica gel. In a modification, Fig. 2, the container A comprises a cylindrical window 2, circular end plates 9, 10, and a central tube 12 which is perforated, and carries an impervious diaphragm 13, the filtering medium D being contained within extensions of the tube 12 and held in place by means of metal gauze covers 14, 15 and spring rings 16. In this form also, the silica gel B is arranged to cover the perforations in the tube 12, so that air cannot pass through the apparatus without traversing some of the silica gel.