What is OMD in engine?

byBijoy Chandrasekhar. In crankcase, oil mist is created 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.

What is the function of oil mist detector?

Oil Mist Detectors protect large diesel, gas and dual fuel engines of all applications. They protect against heavy consequential damage due to oil mist explosions, a result of overheating of bearings or moving parts.

What is OMD in marine engineering?

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.

What is scavenge fire?

marine. The fire of flammable mixture (cylinder oil, unburned fuel and carbon) which can collect in the scavenge space of an engine. Fire in the scavenge air space can be extinguished by steam, water mist or CO 2.

What are you going to do once the oil mist detector alarms?

What will be your action after detecting a hot spot? Keep clear off crankcase relief door to prevent personnel injury, keep fire extinguisher ready and open skylight. Inform bridge, stop engine, open indicator cocks, engage turning gear and turn engine with lube oil circulation continuing to prevent engine seizure.

What is turning gear interlock?

Some of the most common forms of methods used on board ships are manual, electrical and mechanical systems. In ship’s main propulsion or in auxiliary engines, considerable torque is required to overcome the inertia of large reciprocating masses. For this purpose, the energy stored in the compressed air is used.

Can oil mist explode?

When the concentration of oil mist increases and reaches the lower explosion limit (LEL; 50 mg/ℓ, as defined by the IACS), explosion may occur when the mist contacts surfaces of over 200 °C (392 °F) or a spark.

Why scavenging is required?

Importance of scavenging in IC engine An efficient scavenging is important to ensure sufficient air supply to the combustion. The more effective scavenging system, the better fuel combustion and output.

How scavenging is done?

Scavenging is the process of replacing the exhaust gas in a cylinder of an internal combustion engine with the fresh air/fuel mixture (or fresh air, in the case of direct-injection engines) for the next cycle. Scavenging is equally important for both two-stroke and four-stroke engines.