GB983870A - Improvements in or relating to anaesthetising apparatus - Google Patents

Abstract

983,870. Anaesthetic vaporizers. LONGWORTH SCIENTIFIC INSTRUMENT CO. Ltd. Dec. 12, 1962 [Dec. 29, 1961], No. 46677/61. Heading A5T. An anaesthetic vaporizer comprises a dosage container 8 connected by valve means 16, 21, 27 between a storage reservoir 1 and a vaporizing chamber 14 in such a manner that only anaesthetic measured in the dosage container can reach the vaporizing chamber. A valve member 21 is rotatable in a vertical tube 16 which extends through the reservoir and the dosage container, which is transparent. In one position, the member connects the reservoir to atmosphere through a passage 22 in the member and an aperture 17 in the tube and, at the same time, permits liquid anaesthetic to flow from the reservoir into the dosage container through apertures 18, 19 in the tube and a slot 24 in the member. In a second position, the member closes communication between the reservoir and the dosage container and atmosphere and permits liquid to flow from the dosage container to the vaporizing chamber 14, a part of which is transparent, through an aperture 20 in the tube and a passage 25 in the member. Alternatively, the valve between the reservoir, dosage container and vaporizing chamber includes two parts (Fig. 5, not shown), urged apart by spring means into valve closing position, and an actuating rod which, when moved in one direction, moves one part against the spring to interconnect the reservoir and dosage container and, when moved in the opposite direction, moves the other part against the spring to interconnect the dosage container with the vaporizing chamber. A valve disc 27 in the vaporizing chamber is rotatable by a handle 29 and has two apertures 31, 32 which, in one position of the disc, permit liquid to flow from the dosage container into the vaporizing chamber and, in another position, register with apertures 37, 38 in a passage 35, through which respirable gas flows to the patient, the apertures 37 being disposed in a Venturi tube in the passage, so that vapour is drawn from the vaporizing chamber by gas flowing to the patient. A butterfly valve (Fig. 5, not shown) in the passage between the apertures 37, 38 is pivotal on the spindle 28 of the valve disc 27, so that its restricting effect is increased as the apertures in the disc and the passage are brought into full registry to permit maximum flow of anaesthetic vapour into the passage. The Venturi tube is exchangeable with others of a series, each having characteristics suited for a particular anaesthetic.