About Oil Mist Detection
In this section we believe we can show
you how we have overcome the problems
associated with oil mist measurement.
Why use outdated oil mist detectors when
the disadvantages have been overcome as
follows:
- Very slow response time: so that
seizures or explosions have often taken
place before the equipment gives an
alarm.
The reason this happens
is the instrument takes oil mist samples
through pipes which is a slow process
and, at the same time, causes the oil
mist to condense. Further time is lost
as a good concentration of oil mist is
required for sampling. Samples are then
taken one by one to evaluate the levels
of oil mist after which a deviation is
required to operate the alarm. These processes
all add up and the sampling time can take
between 30 and 50 seconds whereas our
instrument will operate within half a
second when properly installed.
- False alarms: The main cause of false
alarms is the use of obscuration as
a measuring system. This is not a sensible
method of measurement as it is dependent
upon the amount of light that is available,
therefore, when the lenses become contaminated
a false alarm can occur.
These systems require clean
compressed air that is not always available.
Invariably the air is not clean which
causes the lenses to become contaminated
very rapidly resulting in false alarms.
- Blocked siphons that become flooded
with oil so that the instrument cannot
function correctly.
- Valves: that can stick.
- Spares: are often difficult to obtain
and, if available, they are normally
very expensive.
The list goes on, but the
main problems have been given above.
The main advantages of the QMI Multiplex™
Oil Mist Detecting System over others:
A 500-m/sec. response times
when the detectors are correctly mounted.
Will monitor up to 12
detection points simultaneously.
The monitor is mounted
in the control room or on the bridge away
from any danger zone where injury can
be caused to engine room personnel
There is no pressure regulator
that can be tampered with which would
increase sample flow causing drop out
or condensation of oil mist.
No need for a heater to
deal with condensation problems
Oil mist is measured at
source and the response time will not
be delayed by oil mist having to travel
along pipes where it also condenses.
There are no moving parts.
The fan is not an integral part of the
monitor.
No expensive clean compressed
air is needed which is not always available
in good supply, especially during engine
start up.
A monitor that needs no
setting up on a running engine as the
detectors are calibrated at the factory
and have a true zero reading.
There are two levels of
alarm i.e., an early warning and a main
alarm together with a shut/slowdown facility.
A self-diagnostic fault
finding system which indicates all the
instrument faults that could occur. All
types of faults are displayed on the monitor
so that the user is kept informed and
need not fear false alarms.
Monitor will work even
when one of the detectors has developed
a problem
A monitoring system that
can oversee more than one engine; monitor
oil mist in the atmosphere around the
plant, at the same time enabling detection
of hazards before fires start.
An instrument that is
able to monitor the gearbox bearings together
with the pistons and external surrounding
for oil mist.
In other words, this all
becomes part of the overall health monitoring
of the engine and not just an alarm system.
It enables the user to keep a watch on
the condition of the engine so that preventative
action can be taken early enough, saving
time and money by avoiding serious breakdowns.
You can read more about
oil mist detection in these three papers
which we have here available in pdf format.
Just click on the title to download.
Oil
Mist Detection as an Aid to Monitoring
an Engine's Condition (PDF format-518K)
by Brian
J. Smith AIMarEST, MIDGTE
Winner of the Akroyd Stuart Award 2001.
First printed in the The Power Engineer,
Journal of the Institution of Diesel and
Gas Turbine Engineers.
Oil
Mist Detection In The Atmosphere Of The
Machine Rooms (PDF format 470K)
You will need the Adobe
Acrobat Reader (free) in order to view
pdf files. Click here
for the Adobe site and step-by-step guide
to installation.
