Gas mixer with a plurality of ejectors for a medical respirator

Abstract

A device and a process for mixing at least a first gas component with a second gas component is suitable for mixing gases in a portable respirator. The gas mixer device makes it possible to bring about the particularly necessary concentration of the first gas component at different volume flows of the gas mixture generated. The gas mixer device has a plurality of ejectors ( ) of different sizes, which are designed according to the principle of a venturi nozzle. The ejectors have respective propellant gas connections ( ) for feeding the first gas component from a propellant gas container ( ) and suction channels ( ) for feeding the second gas component from a mixing chamber ( ), as well as gas outlets ( ) to a respiration connection ( ). An evaluating and control unit ( ) evaluates the signals of two volume flow sensors ( ) and correspondingly actuates proportional valves ( ) arranged in the propellant gas connections ( ) for feeding the first gas component. For small respiration flows, the proportional valve ( ) in the propellant gas connection ( ) for the smaller ejector ( ) is actuated by the evaluating and control unit ( ) for opening, the proportional valve ( ) in the propellant gas connection ( ) for the larger ejector ( ) is actuated for opening in the case of medium respiration flows, and both proportional valves ( ) are actuated by the evaluating and control unit ( ) for opening for high respiration flows.