GB215326A - Improvements in respiratory appliances for personal use - Google Patents

Abstract

215,326. Soc d'Etudes et de Construction de MatÚriel de Protection. May 1, 1923, [Convention date]. Respirators. - In a respiratory apparatus in which the air to be breathed is purified by passage through filtering and. absorbent materials, the layer of filtering material has a corrugated or pleated shape, and the outlet passages which conduct the purified air to the mask are so arranged as to compel the air to follow a sinuous path through the filtering and absorbent materials. To the bottom of the container 1 is secured an inner container 3 made of corrugated metal netting to the outside of which the filtering material 5 is attached, being firmly held by flanges 6, 6<1>. A strainer 7 protected with cotton gauze is fixed at the centre of the container 3, the strainer having a number of holes 9 the diameter of which increases from the top downwards. The absorbent materials 10 are held between the strainer 7 and the wall of the container 3, and are kept in place by springs 11. The absorbent materials may comprise a mixture of activated carbon and basic granulated materials or these may be used separately, being separated by a perforated longitudinal partition (not shown). Dust from the absorbent materials is prevented from reaching the tubes 17, 18 leading to the mask by a filtering layer 15. The tubes 17, 18 are connected by a readily closable union so that air is inhaled directly when the union is open, and through the container 3 when the union is closed. In the latter case air is drawn through the inlets 2 and passes through the filtering layer 5 and absorbent materials 10 to the strainer 7 and tube 17 by way of the holes 7 and tube 17 by way of the holes 9. These holes being of varying diameter, as described above, the air follows a curved downward path, as shown by the arrow f<1>, while passing through the filtering and absorbent materials.