Helium Reclaim Systems
The Gaspure Chamber Gas Recovery System purifies contaminated diving chamber or habitat gases and allows chamber gas recovery during operations and decompression rather than venting to atmosphere. The basic package comprises a Purifier System, a Gas Bag, a Gas Bag Controller and an Alarm Panel. A Gas Transfer Compressor is not supplied as part of this system but will also be required. The Purification System comprises four towers and three filters, manufactured in stainless steel. Disposable cartridges which process 2,834m3 (100,000 ft3) of gas are available in pre-packed pallet packs.
The Purifier comprises eight stages of purification:-
Pre filter F1
CO2 Scrubber
Second stage filter F2
Molecular sieve bed
Purification bed
Activated carbon bed
Catalyst bed
Final filter F3
Gas is routed from chambers, locks and trunks via piping to a three-way valve. This valve routes the gas to atmosphere or to the gas bag. When routed to the gas bag the bag is inflated until the level controller starts the gas compressor. The photo-electric gas bag level controller stops the gas compressor after deflating the gas bag to a predetermined level.
Gaspure Chamber Gas Recovery System
Gas Bags
During normal diving operations Helium is reclaimed from the diving complex using the Gaspure system. This routes Helium vented from equipment locks, bell de-pressurisations, etc. to a gas bag. When the gas bag is filled, gas is pumped to High Pressure Storage via a JFD HP Compressor and filtration system.
A single storage tube within the ship’s gas storage system is normally dedicated to receive this reclaimed Helium and this gradually fills over a period of days. In the past, there has been a problem in re-using this gas due to the fact that it contains significant quantities of air (typically 5% to 10%).
The Helipure system allows this air to be removed and the gas to be safely reused within the dive complex. The build up of nitrogen can affect decompression and oxygen removal enables the gas to be readied for deeper diving.
The Helipure is used periodically, in conjunction with the gas bag, compressor and filtration package of the Gaspure system. Dirty gas (Helium with air) is decanted for the Gaspure storage tube through the Helipure system where the air is removed. It is then passed to the gas bag from where the compressor recompresses the now clean gas and passes it through the filtration package.
After this the gas can be routed into an empty, clean
storage tube for subsequent re-use within the dive system. It should be noted that a gas analysis should be carried out on this cleaned gas before re-use to ensure the oxygen is within usable limits.
