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RBC Odyssey Passive Addition
Semi-Closed Circuit Rebreather
General Specifications
METHOD OF OPERATION:
The "Odyssey" passive addition semi-closed circuit rebreathers were designed
to be used with a single gas source of nitrox, heliox or trimix. The units
are approximately five times more efficient in gas utilization than open
circuit equipment AT THE SURFACE. The relative efficiency ratio increases
with depth. The addition mechanism is keyed to respiratory minute volume and
a full correction is made with every breath, regardless of frequency or
tidal volume. Optimal breathing loop geometry maintains higher oxygen
fractions in the lungs with the same supply mix than other types of
semi-closed systems.
The units utilize an all new operating system that, unlike all other
semi-closed systems, is based on an automatic depth adjusting compound
counterlung. The depth adjustment not only keeps both the primary and
secondary counterlungs equalized during depth increases, but also changes
the ratio between them. Thus, at the surface, approximately 1/5 of every
breath is discharged to ambient, to be replaced by a demand regulator on the
subsequent inhalation (passive addition). At 2 ATA this becomes 1/10, at 3
ATA 1/15, etcetera. This feature makes the Odyssey more efficient than any
other semi-closed rebreather and approaches the efficiency of mixed gas
closed circuit units while eliminating the possibility of hyperoxia due to
electronic, solenoid, regulator or bypass valve failure. The possibility of
unconsciousness due to undetected hypoxia is greatly reduced because failure
of the passive addition will result in the diver getting less gas with
each successive breath, thus providing the same type of warning the diver
would experience when open circuit equipment fails to deliver gas. Any
failure of the depth compensating (compound counterlung proportioning)
device will result in loss of gas use efficiency, not loss of stable
inspired oxygen fractions. The only component that could possibly cause loss
of the system's inspired oxygen fraction stability if it fails is a very
robust silicone mushroom valve in a lexan carrier/seat. There are two of
these in series within three quarters of an inch of one another, further
enhancing reliability through redundancy. Failure of these valves would
IMMEDIATELY cause a drastic change in breathing characteristics that would
be impossible to ignore. In keeping with accepted technical diving
procedures, the addition mechanism (composed of premium open circuit
SCUBA components) is totally redundant, utilizing two supply valves, two
environmentally protected first stages and two second stages.
FEATURES:
Insulated 4 lb. scrubber delivered standard. Other sizes available on request.
Scrubber duration is dependent on ambient temperature and depth. This is a
side fill scrubber. It is exceptionally easy to fill or clean. 26 cu. ft. or
52 cu. ft. gas supply delivered standard. Other sizes available on
request.
Fully redundant passive gas addition system. No single point failures.
Passive gas addition is made when the counterlung is fully collapsed
and no attempt is made to enrich any part of the breathing loop other than
the diver's lungs. This results in stable inhaled oxygen fractions that are
unusually close to the supply gas oxygen fraction.
Buyer's choice of buoyancy control device (BCD) to be mounted on unit.
Hinged case cover for easy scrubber access.
Provision is made for umbilicals and external travel or decompression gases
on "technical" models.
Counterlung is weighted to minimize breathing effort variation during diver
attitude changes.
Counterlung plus all gas discharge and addition components are located
within and protected by the case.
Basic units are slightly negative and evenly trimmed.
1 year parts and labor warranty, exclusive of transportation costs.
Fast service turnaround.
TRAINING:
Unit specific training is provided by the dealer and included in the base
price of $8,500 until January 17th, 1996. After this date all unit specific
training will be conducted at Dive USA in Singer Island, Florida at a cost
of U.S. $800.00.
Buyers are required to satisfactorily complete a rebreather physics,
physiology and water skills course from a recognized technical diver
training organization such as the International Association of Nitrox &
Technical Divers (IANTD) or the Professional Scuba Association (PSA) prior
to delivery of the unit.
Dan Volker
SOUTH FLORIDA DIVE JOURNAL
"The Internet magazine for Underwater Photography and mpeg Video"
http://www.florida.net/scuba/dive
407-683-3592
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