Split Flow - Agilent Technologies Helium User Manual

Technical Information

Split Flow

Activating the split flow option properly characterizes the system to an external
calibrated leak, which is influenced by additional vacuum pumping sources. These
separate vacuum pumping sources reduce the amount of helium measured by the
leak detector. The split flow option is very useful for external calibrations were
external gain factors exceed the limit of 50 due to a high helium background (Range
Stop E-8). The split flow factor is also useful for calibrating to a standard leak while
in the sniffing mode (High Pressure Test).
Figure 44 Split Flow Application
Leak detectors are frequently connected to vacuum systems in parallel with other
vacuum pumps. This can cause errors in readings when testing to a specific value
is important. Split Flow properly compensates for flow differences caused by
additional pumps. Settings available in this mode include:
Setting the value of the installed reference leak.

Step-by-step guidance in setting the split flow value.

Entering set point values for audible and visual alarms.

Enabling an Extended Split Flow routine when testing with low concentrations

of helium and/or to quantify large leak values.
Ground rules and assumptions:
The software limits split flow to no more than 1000 times (3 decades). If the

split flow is turned ON and the leak rate entered is more than 1000 times higher
than the system leak rate, the system will not allow the split flow to turn ON
and <> appears.
Agilent Helium Leak Detector User Manual 97