GB590096A - Improvements relating to breathing apparatus - Google Patents

Abstract

590,096. Respiratory appliances. SIEBE, GORMAN, & CO., Ltd., DAVIS, Sir R. H., and DAVIS, R. W. G. April 11, 1945, No. 9043. [Class 81 (ii)] In breathing apparatus of the type comprising a face mask or helmet which is supplied in accordance with the requirements of the wearer with respirable gas, e.g., air or oxygen, by way of a lung-operated gas admission valve, the valve is integrally incorporated with the face mask or helmet or detachably mounted thereon, and is operated by a flexible diaphragm which is subject to the fluctuating pressure in the mask as the wearer breathes. As shown, a drum 5 jointed to the front of a mask 1 and formed with a perforated diaphragm 6, has mounted thereon a valve body portion 9, secured by means of lock nut 10. Gas passages 13 extend through the valve body and are normally closed by a spring-urged valve 14. The spring pressure is adjusted by means of nuts 17, 19 threaded on the valve stem. The valve is opened by the movement of a lever 21 pivoted at 22 and connected at its other end to a circular plate 26, which bears against a diaphragm 25 of rubber, rubberized silk &c. which moves laterally during inhalation and exhalation. A guard member 28 telescopes over drum 5 and is held in place by a stud and nut 30, 31. Rubber tubing 20 having an internal diameter of about “-inch leads to the low pressure side of a pressure reducing valve connected to a cylinder of compressed air and adapted to maintain a pressure of 10 to 15 lbs. per square inch on the low pressure side. A non-return exhalation valve is fitted to the mask immediately above the drum 5. A flap valve may replace the disc type valve. The device is applicable to open or closed circuit apparatus.