Cressi MC9 Manuel D'instructions page 71

54 SECOND STAGES
inside the case. In order to prevent the depression being too vi-
olent and sucking in the seal, that would cause auto-releasing
(continuous high air flow), the ends of injector and case are de-
signed to direct a light air counter-flow towards the seal.
As we already saw, the air flow released into the injector towards
the mouthpiece increases as it is subjected to the acceleration
known as Venturi effect.
The subsequent depression inside the regulator case keeps the
seal bent and virtually cancels the second stage inhalation effort.
The Venturi effect stops as soon as the divers stops inhaling. The
seal goes back to its original position, the lever pushed by the
spring rises and the nozzle is closed by the piston.
In order to enhance the Venturi effect, XS Compact is equipped
with a new ergonomic flow deviator in two modes, which are
clearly shown on the regulator:
pre-dive and dive (picture on page 14). The former activates a
flow limiter placed in the mouthpiece duct, which cancels the
Venturi effect and the auto-releasing. With the latter on, the Ven-
turi effect is able to work at its best, increasing the air flow re-
leased by the regulator to the maximum level.
DIVE
PRE-DIVE
fig. 14
WARNING: please remember to keep the flow deviator
lever on pre-dive mode while not using the regulator, other-
wise it might start auto-releasing, even harshly, causing a great
consumption of air, in case of sudden shocks, or putting the
regulator under water, or pressing the release button without
having the mouthpiece in your mouth, or taking it out suddenly.
The dive mode is to be used only while diving and with the
mouthpiece in your mouth.
When the diver exhales, he causes the pressure inside the case
to increase and open the discharge valve. The properly calibrated
sized valve has a conical shape which guarantees the regulator to
be perfectly tight in any condition and position of use. Besides,
the second stage case exhaling section has been designed so
as to offer the best performance in combination with the exhaling
baffle.
The latter, which can be taken out of the case by means of a spe-
cial sliding hook, directs all exhaled air away from the diver's face,
thanks to a bulkhead placed on its centre which presses the dis-
charge valve in its middle section making it open in an extremely
controlled way. In this way the regulator exhaling performance is
at its best, while the valve is at the same time protected by the
water turbulence which might open it, when the case inside is not
under pressure, and possibly flood it.
fig. 15