Patent ID: 8387618

Claim:
An oxygen emergency supply device for an aircraft comprising: a pressure vessel configured to contain oxygen under pressure; a shut-off valve connected at its input side to the pressure vessel and connected at its exit side to an oxygen delivery conduit in fluid communication with an oxygen mask; a pressure sensor which measures a pressure at the exit side of the shut-off valve; and a control device which receives the pressure measurement from the pressure sensor, wherein, in response to said pressure measurement said control device causes a voltage having alternating time intervals of on and off to be applied to said shut-off valve such that, during the on time intervals, the oxygen is allowed to flow from said pressure vessel to the oxygen delivery conduit, and during the off time intervals, the pressure prevailing in the pressure vessel causes said shut-off valve to block the flow of oxygen from said pressure vessel to the oxygen delivery conduit such that no oxygen from the pressure vessel flows to the oxygen mask, and wherein a magnitude of the voltage applied to said shut-off valve is directly proportional to the prevailing pressure of the pressure vessel.