Casella CEL Airborne particulate monitor (AMS950-IS) - Manual (Page 6)

AMS950IS -Aerosol Monitoring System
Handbook HB3235-03
3. Principle of Operation.
The instrument uses a beam of infra-red light projected forward into a measurement chamber.
The light is blocked from reaching the receiver by a modified Woods Horn. When dust particles
pass through the measurement chamber, the light beam is scattered forward within a narrow
angle to the receiver. The narrow angle of scatter reduces the instrument's sensitivity to
variations in the refractive index of measured particles.
The instrument is supplied (as Fig.1) in a leather case complete with a shoulder strap. The
leather case is secured to the instrument with a locking arrangement located at the back.
An allen key is provided to unlock and remove the leather case.
The instrument should not be used without the leather case. If for some reason it is, then
the instrument is not then covered by the intrinsic safety certificate.
The probe is made from stainless steel and contains delicate optics and electronics,
therefore the probe should not be used for any other purpose except dust monitoring.
Failure to comply will render the warranty invalid.
Issue 3/NOV 95 Page 6