INFICON Sensistor ILS500F Leak Detection System - Manual (Page 49)

49 Recipes
ninp69e1-a (1410)
Pre-evacuating down to -0.7 atm (-0.07 MPa) means there will be 0.3 atmospheres
(0.03 MPa) of residual air in the pipe before filling.
We will now have:
of air left in the pipe. This is equivalent to 0.57 m (1.9 ft.). This air volume is normally
small enough to be mixed into the tracer gas by turbulence and diffusion.
7.6 Optimizing the Tracer Gas Filling
Regulation of the tracer gas pressure can either be controlled by:
• the ILS500 F
• an external pressure regulator
7.6.1 External Pressure Regulation
External regulation is recommended mainly for very small objects (<50 cc).
Tracer gas pressure is controlled by external regulator. ILS500 F opens a path
between the gas feed line and the test object. The pressure will equate and the tested
object will attain the pressure delivered by the external regulator. ILS500 F checks that
the fill pressure is above Fill Setpoint before proceeding to the next test step.
7.6.2 Internal Pressure Regulation
Tracer gas pressure can be set to be controlled by the ILS500 F. Internally regulated
filling is generally faster than externally regulated. The reason for this is that the
feeding pressure can be set higher than Fill Setpoint which results in a higher fill flow.
B
A B +
------- - E =
0.03
0.5 0.03 +
------------ - 0.056 =
Notice The ILS500 F is set to regulate internally as default.
Notice External Pressure Regulation does not support recipes with different test
pressure (i.e. Fill Setpoints).