Breathing tube (in breathing apparatus)
Encyclopedia
A breathing tube is a flexible tube for breathing through, as part of a scuba set
or other breathing apparatus or a medical oxygen apparatus or anaesthetic apparatus (Here they are distinguished from the medium-pressure hoses which are often found as parts of modern breathing apparatus.)
They are wide, and usually corrugated to let the user's head move about without the tube pinching at kinks.
Each end usually has a screw connection. They may contain a one-way valve to keep the air or gas flowing the right way.
According to the expected usage, they may be pure rubber, or rubber reinforced with canvas (outside or embedded) or similar. If the canvas layer is outside (as in the Siebe Gorman Salvus
and the IDA71 and some old gasmasks, it protects the rubber from damage from scrapes but makes it harder to wash all the salt off after a saltwater dive.
Breathing tubes have to be long enough to connect the apparatus to the diver's head in all attitudes of his head, but should not loop about excessively to cause hydrodynamic drag or risk snagging snag on things, or contain excess dead space
. In the IDA71 the looping over-the-shoulders breathing tubes can be tethered down to the diver's shoulders.
Some early rebreather
s had one breathing tube, which the breathed gas went through both ways: this is called the pendulum system; others have two breathing tubes, with one-way valves keeping the gas flowing the right way.
In some rebreather
s, parts of the apparatus are connected to each other by lengths of breathing tube, resulting in more lengths of tube in the apparatus:
Scuba set
A scuba set is an independent breathing set that provides a scuba diver with the breathing gas necessary to breathe underwater during scuba diving. It is much used for sport diving and some sorts of work diving....
or other breathing apparatus or a medical oxygen apparatus or anaesthetic apparatus (Here they are distinguished from the medium-pressure hoses which are often found as parts of modern breathing apparatus.)
They are wide, and usually corrugated to let the user's head move about without the tube pinching at kinks.
Each end usually has a screw connection. They may contain a one-way valve to keep the air or gas flowing the right way.
According to the expected usage, they may be pure rubber, or rubber reinforced with canvas (outside or embedded) or similar. If the canvas layer is outside (as in the Siebe Gorman Salvus
Siebe Gorman Salvus
The Siebe Gorman Salvus is a light oxygen rebreather for industrial use or in shallow diving. Its duration on a filling is 30 to 40 minutes. It was very common in Britain during World War II and for a long time afterwards...
and the IDA71 and some old gasmasks, it protects the rubber from damage from scrapes but makes it harder to wash all the salt off after a saltwater dive.
Breathing tubes have to be long enough to connect the apparatus to the diver's head in all attitudes of his head, but should not loop about excessively to cause hydrodynamic drag or risk snagging snag on things, or contain excess dead space
Deadspace (in breathing apparatus)
Deadspace in a breathing apparatus is excess space which the flow of air or breathing gas must pass through and back again as the user breathes in and out, increasing the necessary respiratory effort to get the same amount of usable air or breathing gas, and risking accumulation of carbon dioxide...
. In the IDA71 the looping over-the-shoulders breathing tubes can be tethered down to the diver's shoulders.
Some early rebreather
Rebreather
A rebreather is a type of breathing set that provides a breathing gas containing oxygen and recycled exhaled gas. This recycling reduces the volume of breathing gas used, making a rebreather lighter and more compact than an open-circuit breathing set for the same duration in environments where...
s had one breathing tube, which the breathed gas went through both ways: this is called the pendulum system; others have two breathing tubes, with one-way valves keeping the gas flowing the right way.
In some rebreather
Rebreather
A rebreather is a type of breathing set that provides a breathing gas containing oxygen and recycled exhaled gas. This recycling reduces the volume of breathing gas used, making a rebreather lighter and more compact than an open-circuit breathing set for the same duration in environments where...
s, parts of the apparatus are connected to each other by lengths of breathing tube, resulting in more lengths of tube in the apparatus:
- 2 in the Salvus (mask to absorbent canister, absorbent canister to breathing bag; this is a pendulum system).
- 4 lengths in the Lambertsen Amphibious Respiratory UnitLambertsen Amphibious Respiratory UnitThe Lambertsen Amphibious Respiratory Unit is an early model of frogman's rebreather. Christian J. Lambertsen designed a series of them in the USA in 1940 and in 1944...
(mask to exhalent bag to absorbent canister to inhalent bag to mask)