2�9�5 Sealing Arrangement; 2�9�6 Reducing Carbon Dioxide; 2�9�8 Equalizing The Middle Ear - Kirby Morgan 77 Operation And Maintenance Manual

Kirby Morgan 77
®
CAUTION
The fit of the Kirby Morgan helmets is partially
determined by the adjustment of the neck
pad. If the neck pad is not properly adjusted
it may be very uncomfortable on the diver's
neck. Take the time to adjust the neck pad
properly and check the fit prior to each dive
to ensure the adjustment has not changed.
2.9.5 Sealing Arrangement
The neck dam is available in several sizes and is
fabricated in a cone shape. The standard neck dam
on Kirby Morgan helmets is made of foam neoprene.
Optional latex neck dams are available.
The neck dam seals against the diver's neck. The fit
of the neoprene neck dam may be made larger by
trimming 1/4" off the circumference. Only trim a
maximum of 1/4" at a time; trimming too much will
result in a loose fit.
WARNING
Pulling the neck dam over the diver's head
can be difficult. Stretching (expanding) the
seal and placing it part way over the head
can help reduce the force needed to install
the seal. Proper training is necessary to
install the neck seal over the diver's head
and onto his neck. Although the possibility
is very remote, injury may result if this pro-
cedure is not done properly. If a diver does
not know how to don the neck dam, he must
seek proper instruction before proceeding.
NOTE: If you must trim the neck dam, be
careful not to trim off too much material.
The neck dam must fit snugly. While it may
be a slight bit uncomfortable out of the
water, and may feel snug, once in the water
the neck dam will loosen slightly.
2.9.6 Reducing Carbon Dioxide
It is important to reduce the volume of air/gas space
that the diver is breathing through. Carbon dioxide
(CO ) can build up if proper flushing does not occur.
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A rubber oral nasal mask is located inside the helmet
to fit over the diver's nose and mouth. The oral nasal
attaches to the regulator mount nut. This separates
the breathing gas flow from the larger gas space on
the interior of the helmet, and this in turn reduces
carbon dioxide buildup.
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Always be sure the oral nasal valve is prop-
erly mounted in the oral nasal mask. If the
valve is mounted improperly or is absent this
can lead to a higher CO
met. A higher CO
nausea, headaches, shortness of breath, or
blackout.
2.9.7 Communications
In Kirby Morgan helmets, both earphones and micro-
phone are wired in parallel to the communications
module. This module allows for rapid replacement of
the entire communications system. The module can
be equipped with either a waterproof connector, or
binding posts for bare wire connection.
Kirby Morgan uses only high quality speakers and
microphones in its communication system, to help
ensure the clearest possible communications.
2.9.8 Equalizing the Middle Ear
A nose block device allows the diver to block his
nose to provide an overpressure in his middle ear for
equalization. The blocking pad on the inside of the
oral nasal mask is attached to a shaft which passes
through a packing gland to the outside of the helmet.
A knob attached to the end of the shaft can be pushed
in to slide the pad under the diver's nose.
When not needed, the knob is pulled out so the pad
does not rub under the diver's nose. The pad may also
be turned upside down (to provide more clearance
under the diver's nose) by rotating the shaft.
© ⅯⅯⅩIⅡ Kirby Morgan Dive Systems, Inc. All rights reserved. Document # 130318003
WARNING
level inside the hel-
2
level can cause dizziness,
2