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®
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11.0 Interpretation of Results
Figure 5 illustrates the leak detector’s LED light response range. The
greater the number of red or yellow LED lights lit correlates in general to
the size of the leak.
NOTE:
The leak detector is not a quantitative device,
rather it is designed to detect leaks in gas line connections commonly
associated with laboratory equipment.
**
CAUTION:
This unit is designed to detect TRACE AMOUNTS of hydrogen arising from a small leak in a nonflammable environment, e.g., laboratory room air, etc. This unit is rated for use in a
nonflammable atmosphere where the sample gas may become sufficiently high in concentration to become explosive.
Tip drift
Tip drift is the phenomenon when a false LED light response is registered as the unit is quickly turned or swept in dramatic arc movements. Tip
drift is inherent to all dual thermistor leak detector technology and is based in large part on the asymmetry of the flow cells; shaking or tipping
the unit influences the air flow profiles, which impacts the rates of heat exchange. If the device is functioning normally, the LED light signal will
return to zero in 3–5 seconds after the unit is held still. In extreme cases, the unit may require another “zero” cycle before using. To avoid tip drift,
be sure to hold the unit steady while making measurements.
Minimum Detectable
Indicating
Gas
Leak Rate (atm cc / sec)
LED Light Color
Helium
1.0 x 10
-5
Red
Hydrogen**
1.0 x 10
-5
Red
Nitrogen
1.4 x 10
-3
Yellow
Argon
1.0 x 10
-4
Yellow
Carbon dioxide
1.0 x 10
-4
Yellow
Figure 5:
LED light response
chart for the leak detector. A 1:1
ratio of I
Probe
: I
Reference
indicates
no leak present. Red LED lights
indicate the presence of helium
and/or hydrogen. Yellow LED
lights indicate the presence of
nitrogen, argon, and/or carbon
dioxide.
