| 摘要 |
A gas pressure generator (1) for a ventilator (10) includes a variable volume container (30) provided with an inlet (26) connectable to a fresh gas supply and an outlet (27) connectable to a respiration circuit of the ventilator (10); and a driving fluid actuated piston having a shaft (19) with a piston head (21) for transmitting the force to the variable volume container (30) at one end and an opposite end, at which the force is generated, being moveable in a driving fluid chamber (17) so to reduce the volume of the container (30) to maintain a substantially constant output pressure of contained fresh gas. The driving fluid is maintained at a substantially constant pressure with the piston shaft (19) and the chamber (17) relatively dimensioned such that the percentage volume change within the chamber (17) as the shaft (19) moves therein is no greater than an allowable percentage variation in the output pressure of the fresh gas. <IMAGE> |
