3
DPM-RT-2 Operating Manual
2
Overview
The DPM-RT-2 is a self-contained maintenance tool which continuously measures the
concentration of fine particulate matter (PM) in the exhaust of diesel engines, using
standardized tests developed in joint government/mining industry projects.
The measurement principle is based on well-established laser light-scattering
technologies, which are widely accepted and used for measurement of particle
concentrations in numerous laboratory and industrial applications.
The DPM-RT-2 takes this technology several steps further, by adding sophisticated automated data
processing capabilities and by ruggedizing the design to withstand the harsh operating conditions. Simple
and accessible user maintenance greatly reduces the need for
inconvenient “back
-to-
base” servicing.
Ensuring the accuracy and consistency of measurement is vitally important. As well as performing an auto-
zero at the start of each test, the instrument’s calibration can be checked by the operator in
5 minutes, using
the supplied Calibration-Check Plug.
A single HEPA grade filter is used to remove over 99.9% of particles before releasing the measured sample
stream into the atmosphere. The filter unit is a standard screw-off housing design with a disposable filter
element. No tools are required to change the filter element. A second disposable HEPA filter
*
is located
inside the case to continuously filter a stream of ambient air which protects the optical elements from
contamination by soot or moisture in the sample.
*Note:
this filter is only serviced annually when returned to your local service centre or manufacturer.
Unlike other DPM measurement methods which require off-line analysis or manual interpretation, the DPM-
RT-2 continuously displays DPM concentration and provides an immediate test result during and at
completion of a test. This means that maintenance decisions can be made without delay, and the
effectiveness of any maintenance action can be confirmed prior to releasing the equipment back to the
workplace.
Weighing approximately 5kg (including its internal battery), the instrument is self-contained and is designed
for stand-alone operation. With around ~3 hours continuous testing on a single charge, most operators
prefer to use the instrument on battery power.
Designed specifically for operation in the harsh environments typically associated with mobile and stationary
diesel engines, the instrument incorporates several features that enhance its usefulness in
“
real-world
”
situations, including:
•
simple
“
one button
”
operation
•
rugged construction for on-site applications
•
user-maintainable with minimal tools
•
wide measurement range (0
…
420 mg/m
3
elemental carbon)
•
automatic instrument zero setting prior to every test
•
field calibration check in 5 minutes using supplied calibration-check plug
Chapter
2
