CUMA (Canadian Underwater Mine-countermeasure Apparatus) (commercially called SIVA+) is a make of
rebreather
A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's breathing, exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath. ...
underwater breathing set designed and made in Canada for the
Canadian Armed Forces
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The Canadian Armed Forces (CAF; french: Forces armées canadiennes, ''FAC'') are the unified military forces of Canada, including sea, land, and air elements referred to as the Royal Canadian Navy, Canadian Army, and Royal Canadian Air Force.
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by Fullerton Sherwood Engineering Ltd to replace the Royal Navy CDBA.
The unit consists of a back mounted casing, containing its:
carbon dioxide scrubber
A carbon dioxide scrubber is a piece of equipment that absorbs carbon dioxide (CO2). It is used to treat exhaust gases from industrial plants or from exhaled air in life support systems such as rebreathers or in spacecraft, submersible craft or a ...
, oxygen supply, diluent supply (both spherical flasks), a mechanical ratio regulator, electronic PPO2 monitoring, and all of the valves and fittings. The remainder of the breathing loop consists of a pair of chest mounted counter lungs connected by the usual loop of wide corrugated
breathing tubes running from and to the top of the backpack. It has a small
bailout cylinder
A bailout bottle (BoB) or, more formally, bailout cylinder is a scuba cylinder carried by an underwater diver for use as an emergency supply of breathing gas in the event of a primary gas supply failure. A bailout cylinder may be carried by a scu ...
horizontally across the bottom of the backpack casing which is plumbed directly into the divers breathing loop.
It is a self-mixing semi closed circuit rebreather (SCR). A constant flow of oxygen is mixed with a diluent volume dependent on the ambient pressure.
[ The deeper the diver dives, the more diluent is added, and thus the leaner the supplied breathing mix. The correct oxygen setpoint is monitored electronically and alerts the diver via a heads-up-display (HUD) if it is not being correctly maintained. The CUMA is capable for diving to a depth of 90 meters (295 feet) or a maximum working pressure of 10 ATA. It can be calibrated for the use of different diluents such as: air, trimix, ]heliox
Heliox is a breathing gas mixture of helium (He) and oxygen (O2). It is used as a medical treatment for patients with difficulty breathing because mixture generates less resistance than atmospheric air when passing through the airways of the lung ...
, or pure helium.[
Its first ]prototype
A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototyp ...
set was made in March 1987.[
]
See also
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References
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Rebreathers