Chapter 3 – Start-up and settings
UM-23100B-U User manual ATEQ F CLASS Page 25/90
2.3.2. Fill time
This is the time allowed for the pressurisation of the part to be tested. It must not be too
long (waste of time) or too short (the pressure in the component is at risk of not being
sufficient due to drops in pressure caused by temperature changes).
To determine the appropriate fill time, it is necessary to set the Fill Time in order to
make it Too Long (TTLR), then to shorten it until a drop in pressure occurs due to
thermal effects.
Determine the TTLR by using the
following formula :
4
mbar in pressure test x cm in volumeTTLR
3
=
9 Carry out a cycle. When the instrument switches to the stabilisation period, the
pressure must remain stable.
9 A pressure drop (since there will be no fall in pressure due to thermal effects)
signifies the presence of a large leak; check the test part and the pneumatic
assembly components, then start again.
9 If the pressure remains stable, the part does not contain a large leak and the fill time
is too long. Shorten it progressively by carrying out cycles until a drop in pressure is
noticeable.
9 As soon as a fall in pressure due to thermal effects appears, the fill time has become
too short. Increase it slightly.
)Set this parameter using the method described in paragraph 2.3.
2.3.3. Stabilisation time
This time is used to equalise the pressure between the TEST and REFERENCE
components.
Two phenomena may interfere with the equalisation :
9 Different pipes
The first phenomenon that may appear is a pressure variation between the
components, caused by thermal effects. In actual fact, if the connection pipes are
different (length or diameter) the target pressure will be reached faster in the part with
the most favourable set-up. If the differential sensor switches to measurement too early,
the instrument will indicate the presence of a large leak.
9 Different volumes
The second phenomenon which may appear is a pressure difference between the
components due to their differing volumes.
In effect, if, at the end of the fill time, the volumes are different, the component with the
smaller volume will stabilise faster. If the differential sensor switches to measurement
too early, the instrument will indicate a large leak.
9 To determine the correct stabilisation time, it is necessary to set a long time so that
the reading at the end of the test time is equal to zero.
9 Set the stabilisation time to four times the length of the fill time.
9 Carry out a cycle. When the instrument switches to the test period, the pressure
must remain at zero.
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