Functional principle of the CTU
CTU 2xxx series
en-US
Page 21 / 108
BeWa CTU2000 3160738h en-us 2018-11-15.docx
2018-11-15
Functional principle of the CTU
The CTU is a specially designed test bench for analyzing the surface
cleanliness of components.
These components are rinsed off in a clean environment using a test fluid
with a defined cleanliness. The particles carried by the test fluid are collected
on a membrane for subsequent analysis. The results provide information on
the type, size and mass of contamination.
Knowing what type of contamination is involved enables measurements to be
taken to prevent it (improved filtration, transportation, storage, etc.).
After the CTU is filled, the rinsing fluid used is located in reservoir
B1
.
The component to be analyzed is located in the clean room (
30
).
As soon as the operating mode is switched from stand-by to operation,
reservoir
B1
is pressurized.
After entering the desired amount of rinsing fluid and starting the
contamination test via the text display, the rinsing fluid is conveyed from
reservoir
B1
into the analysis chamber via the rinsing fluid micronic filter (
22
)
by actuating the spray gun (
V12
).
The operator has to make sure that the surfaces of the component to be
analyzed are rinsed.
The contamination-particle-laden rinsing fluid is sucked via vacuum action
through the analysis membrane (
14
) and flows into reservoir
B2
. The vacuum
is produced by a vacuum generator (
15
) according to the Venturi principle.
The fill level in reservoirs
B1
and
B2
is monitored via level sensors (
12, 13
).
When the level in reservoir
B1
reaches the lower threshold, the system
automatically changes between reservoir
B1
and reservoir
B2
so that when
processing continues, the rinsing fluid will be pumped from reservoir
B2
to
reservoir
B1
.
The amount of rinsing fluid is calculated by a flow rate meter (
23
). Once the
preset amount has been conveyed, the contamination test is automatically
stopped.
The analysis membrane can now be removed and analyzed.
