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n. (context scuba diving English) A breathing apparatus that recycles expelled air, removing carbon dioxide and allowing extended use of a supply.


A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content of each breath. Oxygen is added to replenish the amount metabolised by the user. This differs from an open-circuit breathing apparatus, where the exhaled gas is discharged directly into the environment.

Rebreather technology may be used where breathing gas supply is limited, such as underwater or in space, where the environment is toxic or hypoxic, as in firefighting, mine rescue and high-altitude operations, or where the breathing gas is specially enriched or contains expensive components, such as helium diluent or anaesthetic gases.

Rebreather technology is used in many environments:

  • Underwater - as a self-contained breathing apparatus, where it is sometimes known as "closed circuit scuba" as opposed to "open circuit scuba" where the diver exhales breathing gas into the surrounding water. Surface-supplied diving equipment may incorporate rebreather technology either as a gas reclaim system, where the surface supplied breathing gas is returned and scrubbed at the surface, or as a self-contained diver bailout system.
  • Mine rescue and other industrial applications – where poisonous gases may be present or oxygen may be absent.
  • Crewed spacecraft and space suitsouter space is, effectively, a vacuum without oxygen to support life.
  • Hospital anaesthesia breathing systems – to supply controlled concentrations of anaesthetic gases to patients without contaminating the air that the staff breathe.
  • Himalayan mountaineering. High altitude reduces the partial pressure of oxygen in the ambient air, which reduces the ability of the climber to function effectively. Mountaineering rebreathers provide a higher partial pressure of oxygen to the climber.
  • Submarines, underwater habitats, and saturation diving systems use a scrubber system working on the same principles as a rebreather.

This may be compared with some applications of open-circuit breathing apparatus:

  • The oxygen enrichment systems primarily used by medical patients, high altitude mountaineers and commercial aircraft emergency systems, in which the user breathes ambient air which is enriched by the addition of pure oxygen,
  • Open circuit breathing apparatus used by firefighters and underwater divers, which supplies fresh gas for each breath, which is then discharged into the environment.
  • Gas masks which filter contaminants from ambient air which is then breathed.

The recycling of breathing gas comes at the cost of mass, bulk, technological complexity and specific hazards, which depend on the specific application and type of rebreather used.

Usage examples of "rebreather".

I were riding through the forested hills above Baidarka 6 Admin Center in a rented Volvo Planetokhod Jeepster, nothing in our ears but the click of our rebreather valves, the soft whisper of static in the headphones.

He loosened the straps at the back of his head and pulled the facepiece of his rebreather unit to one side.

The kit included a microfilament climbing harness, a rebreather and oxygen canister, a first-aid kit with endorphin-boosters, syntheskin patches, and an old-fashioned viral tourniquet.

They had their complete combat-ready vests, weapons, Drager LAR V rebreathers, and fins.

Zuckuss was a Gand, some kind of organic creature who did not breathe the same atmo-sphere these humans did, and thus wore a rebreather mask with tubes and gas jets directed into his lungs.

The two Bajoran brothers went to an equipment chest, not completely closed, in which Kirk could see Bajoran-style rebreathers and diving masks.

The Kookie howled back something about pinpoint erosion factors and a lack of platinum rebreathers.

To dive without pressure force fields, personal propulsers, antigrav buoyancy vests…without even emergency hypopacs of tri-ox strapped to their arms to provide oxygen in the event the rebreathers failed…Kirk felt he was looking at a scene from centuries past.

They were rebreathers using pure oxygen that recycled the exhaled air so there was no telltale trail of bubbles for an enemy to spot and follow directly to the swimmer.

Their radios had been stashed in waterproof pouches on their webbing, face masks and Draeger rebreathers positioned.

The floor was bare tatami except for my sleeping futon and a single chest near the door that held my rucksack, few food items, beer mug, the rebreathers I'd brought from the ship, and my climbing gear: there was nothing to trip over.

It did not surprise me what was wrapped in these three parcels -- nylon, alloy struts and frames, rigging, and in Aenea's packet, more of the same as well as the two skinsuits and rebreathers that I'd brought with me from the ship and all but forgotten.

The Virage was a stable craft and they could stand while helping each other slip into their oxygen closed-circuit rebreathers, of a type used by the military for shallow-water operations.

It took specialized training to use the system efficiently without problems, but Pitt and Giordino were no strangers to rebreathers, having used them for twenty years.

They had rebreathers and flippers, and six sonoboys that would send out locator signals for the submarine.