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OMD(Oil Mist Detector) Control Circuit

Oil Mist Detector control circuit for large diesel and gas engines.

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What and why?

Accumulation of dense Mist in the crankcase of an engine can lead to fire or an explosion. It is important to keep this oil mist under control and for that reason Oil Mist detectors are used.

An overheated diesel engine can become a source of fire and extreme havoc if periodic maintenanceand and proper practices are not carried out. Oil Mist is created in the crankcase when the lubricating oil is splashed by moving and rotating parts of the engine. This oil mist reduces the flash point of the oil, allowing it to catch fire in presence of a hot spot. It is important that this concentration of oil is kept under control and incase its presence is detected, the engine should be stopped or the speed lowered. But how will an engine detect that the level of oil mist has increased in the crankcase?

Oil Mist detectors are used for this purpose. Crankcase of each cylinder is connected to the OMD, which continuously checks the air sample from each cylinder. If the amount of mist increases, OMD raises an alarm. Let's see how it detects the mist.


Working Principle:

Generally air sample is passed through a channel and high intensity Infra Red LED and a sensitive optical Receiver is used crosswise. With normal air, the IR ray is received by the Receiver and when there is mist/smoke then the reveiced signal level reduces. More smoke, lower the ray received and small voltage on the output. With this technique, sample air is being monitoring all the time. Besides, another channel is used through which fresh air is passing through. Ionized Electrodes are used here in this channel and measurement of air quality is done here. Ionized Electrodes are used to detect smoke particles in the fresh air. Comparing this air as a scale, the other channel measures the mist amount and detect the level of the mist. Once the mist density cross the predefined level, it generates an alarm. This alarm is then trigger the main PLC control unit and from where the engine is shuts down to prevend any damage. Now it is your's duty to check the engine oil and replace it with fresh one.


What we are providing?

Once we had a call from Crown Cement Factory for their Oil Mist Detector of a Rolls Royece Engine (4.5MVA Generator Engine). Then we visited the site and checked the installed one and repaired that old one. For safety they gave us a workorder to make a new one as the old one was too old to work with. We did research on OMD and designed our circuits. Collecting various components from Japan and China, we completed the control unit. Then we programmed it and test it. Finally it was ready to install with the engine. After installation, we checked again as a test run. And there was no problem found. So it has been running contineously at Crown Cement Factory (MI Cement Factory Ltd. W. Mukterpur, Munsigonj).


We do this type of works and we can make as per your system requirement. If you are interested please click on  INTERESTED button above and fill up the form and submit your quote so that we can communicate with you back. Thanks.