| 31st
May 2002 |
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First buying trip to B&Q for parts
for connections to counterlung and scrubber, forming the mouthpiece, pipe
for rigid connections and flexible hose for the breathing loop.
|
| 1st
June 2002 |
-
Roughed out holes in top of scrubber
cannister.
-
Modified one spigot on the Hoselok valve
to connect into breathing hose. Inserted directly into breathing hose and
epoxied into place to make a T-piece but the epoxy joint was not strong
enough.
-
Prefabricated rubber diaphragms proved
to stiff for use as non-return valves in the breathing loop so made diaphragms
from discs of rubber cut from an inner tube
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| 4th
June 2002 |
-
Mouthpiece redesigned after the epoxy
joint on Saturday's effort failed. Decided to use one of the 22mm x 22mm
x 15mm T-pieces and the 22m to 15mm reducer pipe to form the mouthpiece.
The steel inserts were removed from the reducer pipe and the piece had
about 15mm cut from the 22mm end and about 3mm from the 15mm end. The spigot
on the Hoselok valve was shortened even more to reduce dead space and the
reducer was epoxied into the spigot.
-
An air tight connection between the breathing
hose and the homemade non-return valves was proving difficult to achieve
so a change of plan. Two drysuit dumpvalves were taken to bits and the
one-way diaphragms salvaged. The diaphragms come in a plastic housing with
a small collar around one end, this was removed so that the valve was in
a straight ~22mm dia tube which was epoxied into each 22mm end of the T-piece.
Initial tests indicated that the air flow was being maintained in the right
direction without any leakage or backflow. The two real tests are if the
epoxy joints will hold (and stand up to elevated ppO2) and if the aftertaste
of the epoxy will fade.
-
Hose connections added to scrubber cannister
prior to cleaning the unit and final assembly before checking watertightness.
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