| 摘要 |
A gas switching device for use with a gas supply system in which two gases, for example, oxygen and air are supplied to a medical unit comprises a manifold 106 to which are attached two identical valve assemblies 108, 110. The manifold has a first inlet 1 and outlet 5 for the passage therethrough of the oxygen and a second inlet 2 and outlet 6 for the air. Each valve assembly 108, 110 includes a spool valve 122 movable from a first to a second position under the influence of the pressure of its associated gas. At least one valve assembly 110 has an inlet 18' communicating with a passageway 15 in the manifold which, in turn, communicates with the inlet 1 for the oxygen and an outlet 22 communicating with a further passageway 16 in the manifold which in turn communicates with the outlet 6 in the manifold for the air. Should the air pressure drop below a predetermined value then spool valve 122 will move to its second position thereby permitting the passage of oxygen from inlet 18' to the outlet 22 in the valve assembly 110 so that oxygen exits from both outlet 5 and outlet 6. |
