Cleaning The Optics; Cleaning The Cell Windows - Malvern Mastersizer Series Getting Started

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Cleaning the optics

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Cleaning the cell windows

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G e t t i n g S t a r t e d
The Mastersizer is a precision optical device. Cleanliness of the optics are
fundamental to ensuring good measurements. It will occasionally be required to
clean the cell windows, range lenses and the beam expander.
One guideline for determining when the optics require cleaning is to observe the
live display when making a background measurement. The display shows the
values for each of the data channels. If any channel gives a value of more than 400
divisions then you are recommended to clean the optics.
Caution!
Always remove the lenses from the optical unit before cleaning. Do not
however remove the actual lens from the lens holder as these are precisely
set at manufacture.
The flow cell is used as an example in this cleaning procedure. The removal and
cleaning of the cell windows are similar on most cells used on the Mastersizer.
Cleaning the system by rinsing through with fresh dispersant a couple of times is
usually sufficient to prepare for a new measurement. Over time you will notice
you cannot achieve such a good background measurement. That is the time to
clean the cell windows.
Make sure that the cell has been drained of dispersant then remove the cell
assembly from the Mastersizer bulkhead. Disconnecting the two sample tubes
from the cell.
The windows are held in place by a metal retaining ring that can be unscrewed by
using the window tool that is found in the accessory case. The cell windows are
sealed by "O" rings.
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To remove a cell window:
. Locate the two pegs on the window tool À into the two holes on the retain-
ing ring.
. Rotate the window tool anti-clockwise and remove the ring Á.
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