GB957978A - Improvements in or relating to underwater breathing apparatus with automatically controlled inlet and exhaust valve - Google Patents

Abstract

957,978. Respiratory appliances. A. NOVELLI, and P. BUGGIANI. Sept. 21, 1960 [Oct. 10, 1959], No. 32418/60. Heading A5T. In an underwater breathing apparatus the pressure-sensitive member controls the operation of both the inlet and exhaust valves, and the valve mechanism is enclosed within said member. Two plate members 1, 2, hinged at 3 and connected by a flexible member 4, form a closed chamber which expands and contracts in accordance with the user's respiration, being connected through a duct 5 with a mouthpiece 6. The end 14 of a gas inlet tube 13 forms a seating for a valve 15 mounted on one end of a lever 16 pivoted on a pin 19 and a second lever 18, on the same pivot, carries the exhaust valve 10<SP>1</SP> for engagement with a seating 9 on an exhaust conduit 7. The two levers 16, 18 are connected at their free ends by a spring 17. At inhalation, the member 1 is drawn towards member 2 and bears on an adjustable pin 23, so as to tilt lever 16 counterclockwise and open the inlet valve. Gas continues to be admitted until, at the end of inhalation, the member 1 moves upwards and allows the inlet valve to close. It remains in this position until the user exhales, whereupon it moves further away and a link 20, engaging under the lower lever 18, opens the exhaust valve, the movement being permitted by compression of the spring 17. At the end of the exhalation the spring 17 lowers the lever 18 and seals the exhaust port. A flap device 22 is carried on the valve disc 10 and is engageable by the lower end of the link 20. During inhalation this link is lowered, as in Fig. 1, and the flap is bent downwards so as not to interfere with the free passage of gas, but, during exhalation, the flap is allowed to rise to the position shown in Fig. 2, where it serves to deflect exhaled air towards the exhaust port. The arrangement also provides for the initial part of the exhalation, which is relatively free from carbon dioxide, being trapped within the chamber while the latter part passes to the exhaust port. It is subsequently breathed in again with the next inhalation.