POSEIDON SE7EN+ - Filling the Cylinders; Chapter 1 Page 10

Poseidon SE7EN+ User Manual Chapter 1 Page 10
Filling the cylinders
From a diving logistics perspective, the Poseidon SE7EN+ differs from normal Scuba in that it
uses two separate gas supplies: a pure oxygen supply and a “diluent” supply. Pure oxygen is
necessary for the control system to exactly replace the oxygen consumed by metabolism. The
denition of a diluent gas in a rebreather is any gas that serves to dilute the oxygen when
mixed in the breathing loop. This diluting characteristic is a requirement of a closed-circuit
rebreather because oxygen is toxic at elevated partial pressures. If one were only using pure
oxygen in a rebreather the standard operating depth would be limited to 6 meters / 20 feet
underwater. Another characteristic of a suitable diluent gas is that it is normally selected so
that it is directly breathable as an open-circuit gas at the maximum operating depth of the
rebreather. General examples of diluent gases that can be used in rebreathers include: air,
nitrox, trimix, and heliox. The SE7EN+ is in its recreational conguration limited to 40 m/130
feet depth and uses only air as an allowed diluent, following established compressed air scuba
sport diving practices. The decompression algorithm requires that air be used as the diluent in
the Poseidon SE7EN+. For technical conguration and deeper setups (40, 48, 60 & 100 m /
131, 157, 200 & 328 ft) refer to Appendix 2.
Poseidon SE7EN+ cylinders (both oxygen and diluent) should be lled by a qualied facility that
is properly trained and equipped to ll such cylinders.The requirements concerning mainte-
nance of oxygen clean systems, gas banks, and compressors are already handled by those
centers and all you need to do is present your cylinders for lling.
For those with less convenient access to such facilities, there are several practical consider-
ations. It may be worthwhile to acquire several spare Poseidon SE7EN+ oxygen cylinders and
have those pre-lled for future dives when needed. If you will be visiting a dive resort or live
aboard boat, inquire ahead as to the availability of oxygen and/or the availability of pre-charged
cylinders on-site that are compatible with the SE7EN+. Note that the SE7EN+ oxygen cylin-
ders sold in Europe contain a DIN M26x2 thread. This is larger than the G-5/8 DIN thread that
is more standard around the world. Poseidon sells oxygen cleaned converters that will allow
lling of the M26x2 oxygen cylinder from a standard G-5/8 male DIN tting.
DANGER:
Filling your own cylinders is dangerous business. You are
personally responsible for your well being and those around you
when you ll your own cylinders. Before you consider this option,
obtain formal training on the operation of the equipment and in the
maintenance of oxygen clean systems. Never overll any Poseidon
SE7EN+ cylinder (oxygen or diluent). Service all equipment per the
manufacturer’s recommendations.
WARNING:
Do not attempt to use any diluent gas in the Poseidon SE7EN+
other than what has been congured in SE7EN+. The use of
other diluents may lead to serious injury or death resulting from
decompression sickness.
IMPORTANT:
Air for compressed air line breathing shall have a dew point
sufcently low to prevent condensation and freezing.
Maximum water content of air at atmospheric pressure:
- 50 mg/m³ @ 40-200 bar / 580-2900psi Nominal pressure
- 35 mg/m³ > 200 bar / 2900 psi Nominal pressure
Corroded solenoids are not covered by warranty.