PURPOSETo make the capacity model of SMART new-type multi-functional ventilator achieve the capability that the flow can be stable and adjusted accurately.

METHODSTo analysis the problems in the course of development with fluid mechanics principle, find the deficiencies of original design and improve it.

RESULTSThe inspiratory phase waveform of IPPV. SIMV,etc, breathing pattern presented square wave, achieved the goal of adjustable flow.

CONCLUSIONSUsing the fluid mechanics principle guiding the design of ventilator gas circuit can get twice the result with half the effort.