| 摘要 |
<p>Valve means for an anaesthetic system which comprises an inhalation means, such as an anaesthetic mask, a gas supply system for the supply of a mixture of gases containing oxygen and an anaesthetic gas, at least one valve (64, 65) for regulating the gas flow in the system and an outlet (67) or the like for the controlled discharge of used gas. The valve means incorporates a sensing means (53, 56) so arranged as to sense the gas speed and the direction of the gas flow in a gas duct inside the system, and a power means (61) so arranged as to cause the valve to open when the speed of the gas in a pre-determined direction exceeds a certain value. The sensing means incorporates a duct (53) with a constriction (56) and on either side of the construction inlets to two lateral ducts (57, 58). The power means (61) is so arranged as to cause the valve (64, 65) to move to its different positions by utilizing the higher pressure which arises because of the direction of flow of the gas and its rate of flow on the arrival side of the constriction in relation to the lower pressure downstream of the constriction. It takes the form of two chambers (59, 60) which are connected to the lateral ducts (57, 58) and which are separated by a movable organ such as a membrane (63) to which the valve is connected. The difference in pressure which occurs in the sensing means as the gas is flowing thus provides control of the valve.</p> |
