GB1446432A - Equipment for administering gas to a patient - Google Patents

Abstract

1446432 Valves T W C DICKENS 16 Aug 1973 [20 June 1972] 28757/72 Heading F2V [Also in Division A5] Apparatus for administering anaesthetic gas to a patient and with provision for scavenging the gas exhaled by the patient comprises a body 1 having a bore 2 communicating with the interior of a mask 5a and with a supply of breathing gas, an exhalation valve seat 8 in an opening in the bore 2, a valve member 10 held against the seat 8 by a spring 14, and a scavenging passage 91 communicating with the side of the valve remote from the bore 2, so that when the patient exhales the exhaled gas passes through the exhalation valve and is removed to a suction source applied to the far end of the passage 21. An annular, metal insert 6 engages in the body 1, its shoulder 7 seating against an annular surface on the body. The insert 6 has peripherally disposed ports 9 and an internal thread to receive an adjuster 13 in which is formed a guide 12 for stem 11 of the valve member 10. A knurled head 15 on the adjuster 13 permits variation in the loading of spring 14. Screws 16 protrude into a circumferential channel 17 in the adjuster so that the latter is axially movable within the limits imposed by the channel. Surrounding the insert 6 is a casing 18 defining an annular manifold 19 into which ports 9 open and to which is connected a source of suction via passage 21. In use, during inhalation by the patient a pressure differential holds the valve shut, and air is drawn through gap 20 into the manifold 19. During exhalation, pressure in the body rises, the valve member lifts, and the exhaled gases are drawn past the valve member through the ports 9 into the manifold 19 and into the passage 21. An anchoring spring 22 or another suitable arrangement may secure the casing 18 to the body, or the casing may be an integral part of body 1.