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I would like to apoligze for the encoded message, I thought the new
system we're using would add it in ASCI text.
Per several requests I am reposting the text that was encoded. It
provides what I feel is the minimum information needed to evaulate the
potential of a tech diving system. As stated, this is the best
redundant full face mask system I have seen or tested. It does, however,
have a steep learning curve. There is a high initial task load in
mastering gas switches, gas sharing procedures, and the effect of head
position on regulator performance.
The manufacturer is listed for informational purposes only.
Description:
1) The first component is a new regulator mounting
block that is designed and manufactured by Greg
Zambeck. The two piece block replaces the current
block used in the AGA full face mask. The nose bridge
and wire form are reused on the new block. The blocks
are machined out of a solid piece of 4" diameter gray
PVC. Currently a dual positively pressurized AGA
regulator mask has been tested to 300 FSW. A dual ODIN
regulator block has been machined and is being tested
in the same depth range. A third block having a
pressurized AGA regulator on the top and an ODIN
regulator on the bottom is under construction for
testing. All configurations have the exhaust ports on
the same side. The blocks are machined in a V
configuration as an engine block would be. the complex
angel of these two surfaces angles the regulator hoses
together. The communication port is machined parallel
and converging to the hoses. The hydration port is
offset toward the regulator exhaust ports to allow for
connecting U/W. All configurations allow the diver to
operate the Pre-dive switches and hydration connector
U/W with a five finger gloved hand. Ducting for the
defroster circuit is provided from each regulator. The
area of ducting from the block is increased from 103%
to 114% compared to the single regulator block sold
with the AGA full face mask.
2) The second component is a gas "gang" block that
allows the diver to choose between gas supplies and the
regulators in use. The gas "gang" block is composed of
two (2) Swaglock open ended quick connect (B-QC6-s-4PM)
stem fittings and two (2) Whiety three way SS
(stainless steel) ball (B-44FX4) valves. The bottom
ball valve is used to switch from one gas source to
another.
Hose behind |========== Mask ==========| Hose behind
divers arm | / \ | divers arm
| Comm./ \Hydration|
| |
|==Hose== Three Way==Hose==|
Valve
|
Belt loop for waist strap |
|
|==Quick connect===Three Way Valve===Quick Connect==|
| (Gas In) (Gas In) |
|Hose Hose |
|===1st Stage Regulator 1st Stage Regulator===|
The top ball valve is cross drilled to allow for
various uses of the two second stages. When turned
toward one hose or another the diver is selecting the
use of the top or bottom regulator. When turned
directly toward the diver both the top and bottom
regulators can be used.
The bottom regulator is used for breathing at depths of
200 FSW+. The predive switches on this system can be
made to engage at 180 to 200 FSW by making adjustments
to the position of the valve lever.
Drop-Line
|
Check Valve
|
QC-Body====7 ft hose===TEE===7 ft hose====QC-Body
Drop Lines:
When connecting to any drop-line a Swaglock check valve
(B-4CP4-1/3) should be used at the bottom of the hose.
Loss of pressure in a drop-line will result in having
the divers face vacuumed into the mask. Blood vessels
in the skin will break first and then the vessels in
the eyes. The eyes will look blood shot as if a minor
decompression (20 ft or less) is experienced. Beyond
this depth loss of vision is assured, with other forms
of localized decompression (the brain) following.
Immediately changing to another gas supply using the
bottom ball valve solves this problem, and for any
other loss of gas supply pressure.
The Swaglock quick connect (B-QC6-B-6PF) body operates
the opposite of most air fittings. The QC-body has a
large section to hold with a gloved hand as it is
pushed onto the stem, requiring about thirty seconds to
make a gas change. This body has an enlarged collar
that snaps into place holding the two fittings
together. The collar is pushed toward the stem to
release the fittings. The body is made of brass with a
stainless steel coating. The coating has a high
lubricity when new and needs to be oxidized for use.
To avoid separation the diver must be careful not to
bump the collar on a new fitting. Because of this
feature the diver MUST learn to hold the manifold by
the VALVE ONLY!!!, as the body is pushed onto the stem.
Stem and body fittings larger in diameter than this are
difficult to connect without reducing the intermediate
pressure below 145 psi.
Other index locking QC fittings require the collar to
align with a ball before the collar can be moved. This
type of connector is very difficult to use with a
gloved hand in cold water. The lead time required to
connect prior to a gas switch with these valves is
increased to about two minutes. Due to the short
length of this fitting it is only recommended for use
with an ungloved hand.
Staging: The use of QC fittings substantially reduces
the cost of regulator systems for multiple gas dives.
A stage bottle would generally have a short 30" hose
for the diver carrying the bottle to use. A seven foot
hose is recommended for a second hose and all drop
lines.
Standard Use Procedures:
Decent Gas Mix (Dive): The decent gas or travel mix is
connected to one inlet stem and the bottom mix to the
remaining inlet stem. Both supple regulators are
tested and then the mask regulators are tested. The
diver uses the travel mix to enter the water and makes
the change over to the bottom mix at the predetermined
depth.
Bottom Gas Mix (Dive): The second source of the bottom
mix is connected after the gas change over has been
made, as the diver continues to descend. The stem used
for the travel mix is disconnected and the second
bottom mix regulator hose is connected. If the diver
bumps the collar of the regulator being used at this
time the gas supply is shut off immediately. With
connectors that are oxidized, the body will stay on the
stem, and only needs to be reconnected. Because of
this problem, hoses connected to the tanks carried on
the divers back should be fastened to "D-rings" on the
front of the diver's belt. Double snap hooks work well
for this purpose. The diver uses the double hook to
separate different gases (bottom & travel) by locating
each hose in the top or bottom position of the snap
hook.
Ascent Gas Mix (Decompression): the use of high
pressure drop lines (below 100 FSW), or drop tanks
should be placed 10-20 ft deeper than their required
depth. This allows for an adequate amount of time to
connect the decompression gas before the gas change is
made. For decompression stops of one minute allow 10
ft of extra hose. For ascents at 30 ft/min. allow 20
ft of extra hose. When using low pressure hoses (above
100 FSW) 10 ft of extra hose is adequate for allowing
the diver to disconnect and reconnect before switching
to the decompression gas. Hoses should be marked with
the type of gas (AIR, NITROX, OXYGEN) to avoid
confusion.
Gas Sharing (Out of Gas Situations): This situation
can be handled with the use of a seven (7) foot hose
with both a male and a female quick connect end. The
diver supplying the gas would disconnect one gas source
from his manifold and attach the seven foot hose. The
assisting diver would connect the hose to the diver
needing gas and switch the ball valve to the new
supply. this reduces the change over time because the
diver needing assistance can not see his manifold stem
and is a little panicky during the operation. When the
seven foot hose is connected water will splash on the
inside of the visor and in the divers eyes if a hard
breath is taken. The seven foot hose must be left open
or the air trapped in the hose will compress, making
the task of disconnecting the two ends difficult. Use
in salt water would require a thorough flushing after
each use, and stainless steel fittings are recommended
instead of brass. Since the full face mask is not
removed, both divers still have communications and
hydration systems available throughout the dive. This
system increases the divers task loading and requires
practice for competent use!
Tuning (Mask) of the positively pressurized regulators
must be done with the mask submerged. This requires
making adjustments to the regulators breathing
resistance and then checking the cracking pressure
resistance while wearing the mask underwater. The top
regulator, is adjusted with a higher breathing
resistance for use during decompression. The
adjustment used to increase spring tension is used to
achieve this. During the adjustment process the diver
changes their head position from directly face down to
face up, and continually rotates their head from side
to side.
Because of the cracking pressures that are used in this
system, the dual regulator mask will free flow at
different head positions. This is based on the head
position, cracking pressure, and the activation valve
adjustment. To stop a free flow the diver would change
their head position or change the regulator in use.
This is done at the top ball valve or by use of the
predive switch.
Cost of the systems range from $600-700 depending on
the configuration and size of the system required. For
more information on these systems, contact Greg Zambeck
between 8:00 to 4:00 central time at (708) 978-8000
x222.
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