Uson SPRINT LC, Owner'S Manual

Page: 106 / 208

Page 106
Occlusion
(Blockage)
Test
How OCC works
An occlusion test (also called a blockage test or a gross pressure loss test)
is a method of testing in which pressure in an open product must drop
below the reject level for a pass condition. Occlusion tests are generally
used to evaluate products that have openings to check for potential
blockages or obstructions of the flow path.
Depending on the model, your tester may or may not have the ability to
conduct occlusion tests. All pressure decay testers come with occlusion
testing as a standard. Occlusion testing is not available on testers with
flow capability.
Most of the parameters are the same as a PD test
All occlusion test parameters are defined the same as in a pressure decay
test, with the exception of the reject level. The reject level is the reverse of
a pressure decay leak test. Rather than expecting the part to hold pressure
we now expect the pressure to flow to atmosphere. The occlusion test
expects the pressure to drop more than the reject level.
For simplicity we will not repeat the definitions of all the parameters or
how to program. For more information see the explanation of a pressure
decay test starting on page 92.
Results in Pressure Decay or Flow Rate (Volume/time)
The results of an occlusion test are usually displayed in pressure drop. The
tester can also display the result in units of cubic centimeters per minute
(ccm). Simply enter the volume of the part under test to activate the
conversion to ccm flow rate. When zero is entered as the product volume,
the calculation to ccm is disabled and the results are displayed as pressure
loss in units of psig.