Technical Data - Ulysse Nardin UN-320 Mode D'emploi

HELIUM VALVE
The Helium Valve is useful when saturation diving with a closed div-
ing bell (a rigid chamber put at the same pressure than the water).
Saturation diving is a diving technique that allows divers to reduce
the risk of decompression sickness when they work at great depths
for long periods of time. The closed bell is a pressure vessel for
human occupation, which may be used for bounce diving or satura-
tion diving, with access to the water through a hatch at the bottom.
The objective for the watch is to avoid that the glass pops out and
breaks. As the diver ascends in the chamber, the gas pressure out-
side of the watch decreases, with the pressure inside of the watch
remaining higher.
Once the difference is too great, the pressure buildup causes the
crystal to pop off the watch. Helium valve allows helium atoms
to escape during decompression. The Helium valve has two po-
sitions: Screwed - the valve is closed to avoid dust to enter into
the mechanism. Unscrewed - the valve has to be opened during
saturation diving to allow the pressure to come out of the watch.
Helium valve on modern watches are paying tribute to a long tradi-
tion of diving instruments and diving watches in the watch industry.
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MAINTENANCE
All mechanical watches should have their movements cleaned
and the oil replaced every 3-5 years. The life span of any mecha-
nical timepiece will primarily depend upon both daily care and the
recommended routine maintenance. We strongly encourage you
to have your timepiece serviced only at official authorized Ulysse
Nardin after sales service departments. For additional information
regarding after sales service please visit our website:
ulysse-nardin.com

TECHNICAL DATA

Caliber UN-320
Type Mechanical self-winding movement
with silicium technology
Size 11 3/4'''
Diameter of movement 26.40 mm
Height of movement 4.60 mm
Number of jewels 39
Oscillations 28,800 V/h (4Hz)
Power reserve approx. 48 hours
Display Small seconds hand decentred at
5 o'clock, date at 3 o'clock
Case Titanium
Diameter 46 mm
Water resistance 1000 m
Strap Rubber with expendable elements
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