Ventilation apparatus

Abstract

An apparatus for preparing a ventilation gas mixture, the apparatus comprising: a first gas feed configured to receive carbon dioxide via a first gas valve; a second gas feed configured to receive oxygen via a second gas valve; a gas mixing device 5 configured to receive the carbon dioxide and the oxygen from the first and second gas feeds and combine the carbon dioxide with the oxygen in the gas mixing device to form a ventilation gas mixture; an adjuster configured to adjust the first and second gas valves between an open position and a closed position in order to adjust the relative amounts of carbon dioxide and oxygen forming the ventilation 10 gas mixture; and wherein the adjuster is configured to adjust the first and a second gas valves based on an air pressure applied to the apparatus.

Dependencies are inferred from the claim text.