Abstract: Means for reclamation of helium from diving apparatus comprise a bell conduit coupled to the discharge valve of a diving bell, a first receiver coupled to the conduit and arranged to receive gas from the bell, a second receiver coupled through a regulating valve to the first receiver, the regulating valve being arranged to close upon increase of pressure in the second receiver, a compressor and a storage tank (or bank of storage tanks), and further conduits interconnecting the second receiver, compressor and storage tanks for gas flow therebetween.

Abstract: This invention relates to a diver's re-breathing apparatus of a closed circuit type. The gas circuit is provided with a solenoid valve coupled to an oxygen cylinder and arranged to be energised to introduce oxygen into the breathable atmosphere when the oxygen content therein drops below a certain proportion.The electrical circuit comprises a pair of transducers in the gas circuit, one of which is sensitive to oxygen partial pressure and the other sensitive to total pressure, the outputs of the two transducers being amplified and fed into an analogue divider, the output of the divider being responsive to percentage of oxygen in the breathable atmosphere and being effective to energise the solenoid to thereby maintain the oxygen content of the breathable atmosphere within limits of percentage, rather than within limits of partial pressure.