Controlling delivery of gas via a supply duct

Abstract

Abstract 1344321 Respiratory apparatus SIEMENS AG 19 April 1971 [13 April 1970] 27298/71 Heading AST Apparatus for use in controlling delivery of gas to a respirator via a supply duct, comprises a gas reservoir 1 of variable volume having inlet ducts 4, 5, 6 for receiving gas, an outlet connected to the supply duct 11, and two tension springs (23, 26) Fig. 2 (not shown), arranged to maintain gas pressure in the reservoir substantially constant, despite variation in its volume within predetermined limits, during such delivery. The two tension springs (23, 26) are effective between the housing of the apparatus and a lever member (21), to bias the lever member against a movable wall portion 17 of a bellows 1, the arrangement of the springs being such, that variation in the tension of one of the springs, as a result of variation in volume of the bellows, is substantially compensated by the accompanying variation in the tension of the other spring. The inlet ducts 4, 5 and 6, respectively are provided with non- return valves 7, 8 and 9 for the supply of various gases to the bellows 1 via a conduit 2 and filter 3. The duct 6 is provided with a flowcontrol valve 10 which operates in dependence on the volume of the bellows 1 by means of a rod 15 cooperating with a pivotally mounted lever arm 16, the lever arm being acted upon by the lower wall portion 17 of the bellows 1. The supply duct 11 has a safety valve 12 which connects it with the atmosphere when a predetermined upper critical volume limit of the bellows is exceeded. Oxygen and anaesthetising gas may be supplied at a constant rate through ducts 4 and 5 respectively, and air may be supplied through the duct 6 as a function of the volume of the bellows 1.

Inventors

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