Oil Mist Detection and Alarm systems for engine and machinery spaces, for gear boxes, and for slow, medium and high speed diesel engine crank cases.

What is Oil Mist

There are two ways oil mist can be formed. One source is minute leaks in pressurized in oil lines and fittings which produced a atomized spray of oil into the atmosphere. The second source is when oil hits a very hot surface and boils.

Danger occurs when high pressure type of leaks of oil mist are formed with a particle size of 3 to 10 microns that builds up to a hazardous concentration of mist in the atmosphere. At levels of saturation conditions are truly hazardous, and if no action is taken a fire can start. The ignition temperature for this type of oil mist can be extremely low depending on the fuel that is being atomized. 

Other ways an oil mist can be generated is when drops of oil hit a hot spot or surface and boils. When oil mist is produced by boiling the particle size is then 3 to 10 microns. This mist is visible and is known as "blue smoke". The larger and hotter the hot areas is the quicker the oil mist is produced. At this stage a temperature as low as "150°C can cause ignition.

Some sources of oil mist:-

• leaking injectors
• fractured flexible hoses
• loose or incorrectly fitted pipe fittings
• broken welds
• poor maintenance of machinery.

Some causes of Ignition

• exhaust pipes
• turbochargers
• non-flameproof motor housings
• electrical contacts
• static electricity
• faulty wiring

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.