User manual
Poseidon MKVI User Manual
Chapter 1
Page 30
13. Scrubber
The largest physical element of the rebreather is the CO
2
absorbent system, also referred to as
the “Gas Processor” unit (it physically includes the gas sensing and electronics control modules).
The outer shell of this system (shown in Figure 1-46) comprises the structural backbone of the
Poseidon MKVI and both the diluent and oxygen cylinders attach to the side of this extruded
aluminium tube. The top section of the housing is the mounting structure for the electronics
module. The main tube is the housing for the CO
2
absorbent cartridge. The base plate seals
the housing and also allows for modular loading of the CO
2
absorbent cartridge.
Because CO
2
production rate is closely correlated with oxygen consumption, the Poseidon
MKVI was designed such that the CO
2
absorbent cartridge duration corresponds to the oxygen
cylinder capacity. Thus, the absorbent cartridge MUST be replaced whenever the oxygen
cylinder is relled. To remove the spent cartridge, loosen all four (4) large hand nuts at the
bottom of the cartridge housing to the point where they spin freely (no tools are required; see
Figure 1-48).
The canister has been tested for a duration of 180 minutes at 40m, water temp 4°C, and a
breathing rate of 40lpm producing 1.6 l CO
2
per minute at STPD (Standard Temperature &
Pressure, Dry in accordance with EN14143). The canister duration is afected by depth; diving
the MkVI to 60m reduces the performance. At 60m the canister has been tested for a duration
of 120 minutes, water temp 4°C, and a breathing rate of 40lpm producing 1.6 l CO2 per
minute at STPD (Standard Temperature & Pressure, Dry in accordance with EN14143).
With the nuts loose, pull the webbing handle on the bottom of the housing in a fashion, so that
it moves in the opposite direction from the electronics housing. Because o-ring seals can “set”
with time it may be necessary to restrain the tube with one hand while pulling with the other
(see Figure 1-49). Make sure that the nuts are completely free from the heli-coils before pulling
out the bottom lid.
Once the dual radial seals on the end cap have cleared the end of the housing tube, the CO
2
absorbent cartridge will freely slide out, as shown in Figure 1-50.
SofnoDive
®
797 Pre-pack
CO
2
absorbent Cartridge
Outer shell - Cartridge housing
Figure 1-46.
Overview of the cartridge house and the CO
2
absorbent cartridge.
Figure 1-47.
The CO
2
absorbent cartridge with the SofnoDive
®
797 Pre-pack CO
2
absorbent Cartridge inside.