Pressure Drop Test; Plate Holder Test - Sartorius Sartocheck 4 plus Operating Instructions Manual

12.1.3 Pressure Drop Test (Only valid
®
for the Sartocheck 4 plus Filter tester)
12.1.4 Plate Holder Test (Only valid
®
for the Sartocheck 4 plus Bag tester)
74 Appendix
The Pressure Drop Test is based on the change in pressure within a filter system
connected upstream. This change is caused by the diffusive gas stream flowing
through a wet membrane at a given test pressure (see "Diffusion Test").
The pressure drop measured in the process can be directly used as the measure
of the filter system's integrity, provided that the upstream volume of the system
is constant and known.
At the same diffusion rate, lower pressure drops are yielded for larger upstream
volumes, and higher pressure drops for smaller upstream volumes.
Because the result is volume-dependent, this is mainly recommended for leak
testing empty housings with a known volume. It can also be derived from the
following simplified equation for determining pressure drop based on diffusion,
test time, net volume and atmospheric pressure:
D · t · P
0
– – – – – – – – – – – – = p
V
N
p = Pressure drop in mbar within test time "t"
D = Gas diffusion in ml/min
t = Test time in min
P = 1000 mbar or barometric pressure in mbar depending on setting
0
V = Upstream volume of the system in ml.
N
For this reason, a Pressure Drop Test is recommended mainly to leak-test empty
housings and pressure vessels with a known volume.
The plate holder test and the installed bag test are based on pressure drop measure-
ment. The eventual change in pressure is caused by the diffusive gas stream flowing
through an eventual defect in the plastic film of the bag. The pressure drop measures
conformity of the bag set-up, provided that the volume of the system is constant and
known.