Gasmizer Manual - Submarine Manufacturing and Products Ltd

March 2009
setting of the regulator is adjusted automatically as a diver moves above or below the bell.
Depending on the type of exhaust valve fitted to the diving helmet, it may not be necessary to
use the diver tracking system. Gas then passes through a non-return valve and an external
water trap to surface for re-processing.
One Diver
Two Diver
Fig 3
Bell Exhaust Equipment
1.5 Reprocessing Unit
1.5.1 The Reprocessing Unit is bulkhead mounted. Fig 4 and Fig 5 illustrate the unit. Gas
passes from the exhaust hose of the bell umbilical to a coalescing moisture separator and
particle filter, which removes all particles, both liquid and solid, down to one micron. Next, gas
flows through a float valve which prevents water contamination if, for example, a hose fitting is
loose on the bell. Next, a back pressure regulator similar to that in the bell, controls the pressure
in the exhaust umbilical. Gas then flows to 2 receivers into which oxygen is injected at a preset
rate to compensate for the divers’ oxygen consumption. Before passing to the gas booster, a
further stage of filtration is provided, which removes particulate, biological or liquid particles
down to .01 micron.
1.5.2 On returning from the gas booster carbon dioxide is removed and the breathing gas
purified in scrubber canisters containing soda lime and Purafil. Two independent canisters are
provided, either of which may be isolated, vented and re-filled while the other is on-line.
1.5.3 Finally, any remaining moisture is condensed out in a “tube in tube” type water-cooled
heat exchanger. The gas then passes through a final one micron coalescing filter on its way to
the volume tank.
Chap 1 Page 5 of 168 OM002 Rev 5