GAS PROPORTION CONTROL DEVICE FOR AN ANAESTHETISING APPARATUS

摘要

In anesthesia apparatus for supplying oxygen and an anesthesia gas through respective flow control valves to a patient breathing circuit an oxygen flow ratio controller is provided. The system includes a restrictor in the pipeline of the oxygen flow control valve and a restrictor in the pipeline of the anesthesia gas flow control valve. The oxygen flow ratio controller includes differential pressure sensing means and anesthesia gas flow control means, the differential pressure sensing means includes a diaphragm assembly responsive to the pressure in the oxygen pipeline and another diaphragm assembly responsive to the pressure in the anesthesia gas pipeline and is coupled to the restrictor pipelines. The anesthesia gas flow control means controls the flow of gas to the anesthesia gas pipeline. The diaphragm assemblies are opposed to each other and are coupled together by a displaceable linkage. The linkage is also coupled to the anesthesia gas flow control means to control the flow of anesthesia gas therethrough in response to the differential pressure existing in said pipelines.