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Background of Oil Mist Detection
Oil Mist Detection In The Atmosphere Of The Machine

presented at the Marine Propulsion conference in Bilbao, January 2005
Oil Mist and Machinery Space Fires PDF
Oil Mist and Machinery Space Fires
(PDF format- 186K)
Oil Mist Detection as an Aid to Monitoring an Engine's Condition PDF

TWO levels of alarm

- an EARLY WARNING and a MAIN ALARM together with a shut/slowdown facility.

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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Why use outdated oil mist detectors when the disadvantages have been overcome as follows: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 In The Atmosphere Of The Machine
Rooms - New regulations for atmospheric oil mist detection
(PDF format-476K) This paper was presented to the Marine Propulsion conference in Bilbao, January 2005.

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 Engine Room (PDF format-100K)
by Brian J. Smith AIMarEST, MIDGTE
Oil Mist and Machinery Space Fires (PDF Format)
by Dr MH Holness PhD, C Chem, FRSC, M Inst Pet.
IMO Code of Practice for Atmospheric Oil Mist Detectors (PDF format - 234K)
International Maritime Organisation
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.


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