Cleaning The Range Lenses - Malvern Mastersizer Series Getting Started

C H A P T E R 1 1
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Cleaning the range lenses

P a g e 1 1 . 6
G e t t i n g S t a r t e d
If this does not eliminate the mark then consider the use of a liquid cleaner such
as Ethanol Absolute or Propan-2-ol. This can be soaked on a cotton wool bud 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 any sign of damage they should be replaced.
Re-assemble the windows by first fitting the O-ring to the retaining ring then
pushing the window into position. (Place a piece of tissue over the window to
prevent finger marks getting onto the surface.) 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
pump speed is changed, causing the system to mis-align.
Replace the cell onto the Mastersizer and reconnect the sample tubes. 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.
The range lenses should not require cleaning often. If you find that you are
getting poor background measurements then the lenses may require cleaning.
The range lenses may be cleaned when removed from the optical unit. First
remove dust from the lens without rubbing. An aerosol clean air duster or a
camera blower brush are both suitable ways to achieve this.
Inspect the lens by reflected light and see if there are smears or prints on it. If so
then you must wipe the lens surface using the guidelines described in the section
"Cleaning the cell windows" above.
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