Programming
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or the pressure does not drop at all. A crack test uses a second
sensor downstream from the part to catch a pressure rise or flow
coming out of the part.
Downstream Sensing
In some test parts, the crack (pressure change) is so gradual or
low in magnitude that the sensor can’t detect the pressure change.
This isn’t a fault of the sensor, rather the placement of the sensor
in the test circuit becomes an issue. Being upstream from the
product, the normal sensor is subjected to constant makeup air.
To test products that open slowly or merely “weep,” Uson can
provide a separate sensor used downstream from the cracking
device to detect very slight pressure or flow changes. In this
arrangement, the downstream sensor measures the small pressure
or flow variations caused by changes in the product being tested.
This arrangement works if downstream air can be routed back to
Sprint iQ.
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