Malvern Instruments Mastersizer X, Manual

Page: 73 / 102

%
Caution
Inspect the window by reflected light and see if there are any smears or prints on
it. If so then you must wipe the lens surface using the following guidelines.
.
Use a good quality lens tissue and gently wipe it once over the wetted sur-
face of the window. Do not put your fingers on the lens during this wipe.
Re-inspect the window and if still marked then repeat with another clean
tissue.
.
If this does not eliminate the mark then consider the use of a liquid cleaner
such a Ethanol Absolute or Propan-2-ol. This can be soaked on a cotton
wool bud or tissue and wiped across the window gently. Use one pass over
the window and then discard to avoid scratching. Re-inspect the window
and repeat until clean.
The outer faces of the windows have an anti-reflective coating and are more
prone to scratching than the inner surfaces. Be careful not to touch the faces of
the windows or put them down on dirty surfaces.
If the “O” rings shows sign of damage they should be replaced.
Re-assemble the windows by first placing the window into the retaining ring
(place a piece of tissue over the window to prevent finger marks getting onto the
surface), then pushing the “O” ring into position. The window has a chamfered
edge and the side with the widest diameter must face outward. The diagram
above shows this orientation
Ä
.
Screw the window ring back in place. Ensure the window is fully home in the
mount and not held by the “O” ring, otherwise the window will move when the
dispersant flow speed is changed, causing the system to mis-align.
Replace the cell onto the Mastersizer and reconnect the sample tubes, if
applicable. To check the integrity of the cell, pump dispersant through it. Check
that no dispersant leaks from the cell or sample tube connectors.
(
N o t e :
. The cell windows are part of the optical system and removing them for
cleaning will change their position. Remember to add an Align stage to
your next measurement sequence or click the Align Easy button.
Do not wipe the windows with an ordinary dry cloth as this will cause
scratches. Always use the procedure below to clean the surfaces.
C H A P T E R 9
Q S S M A L L V O L U M E S A M P L E D I S P E R S I O N U N I T
P a g e 9 . 7