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PD (Pressure Decay)
There are four timers in a typical pressure decay test. Optional timers would include Clamping
and Fast Fill.
Fast Fill
–
This timer requires optional pneumatic components to operate and works in
conjunction with the
F
Fill Press
ure field. Fast fill is a primary fill step used to quickly fill large volumes
by using a secondary regulator set at a higher pressure to increase the volume of air being introduced
into the part. This step will terminate at the completion of the timer or when the entered pressure is
reached (Radio button selection). A step with a time of zero will be skipped.
Fill
–
the Fill timer is the amount of time allowed to reach the test pressure, and is subject to the
pressure tolerance. If the pressure increases above the plus tolerance a HI PRESSURE error will occur
and will end the test. If the fill time elapses without the pressure reaching the test pressure minus
tolerance a LO PRESSURE error will occur and end the test.
Settle -
At this point the supply pressure has been isolated from the unit under test. During this
timer the air and the part are allowed to settle. Parts that have a more flexible nature should be given
more time to reach a steady state for testing. If the pressure drops below the test pressure minus
tolerance a GROSS LEAK error will occur and end the test.
Test -
During this step the decay of pressure is monitored. If the decay is equal to or greater
than the reject level, the test will end and a reject indicator will illuminate (RED LIGHT) and an audible
tone will alert the operator of the failure. If the pressure does not drop below the reject level and the
time expires, the part is has passed and an accept indicator will illuminate. (GREEN LIGHT).
