How do you prevent oil mist from a ships’ engine filling the engine room and other parts of a ship?
All internal combustion engines have a ‘breather’ which is basically a system of pipes which connects the crankcase and cam shaft casing to atmosphere, ensuring that those spaces are not over pressured by combustion gases leaking past the piston ring seals and valve sleeves. Moderate leakage of combustion gases ensures that there is always a movement of gas along the breather pipe to atmosphere, and inevitably there is some oil mist that is discharged out of the breather pipes. Most small engines have some primitive oil mist eliminator for catching this mist and if properly designed the oil mist once captured should drain back to the sump. On very large engines such as those found on auxiliary power and marine applications something a little more sophisticated is called for.
On large marine engines the IMP 38 oil mist eliminator finds an ideal application. From large marine engines the steel breather pipe is usually either 2, 3, 4, 6, or 8″ Ø. The pipe layout usually has an upward run before it reaches atmosphere, so that oil mist can impinge and condense on the walls of the pipe as it cools before draining by gravity back to the sump of the engine. Without any active mechanism for collecting oil mist the smaller oil droplets would be discharged into the general air space, where in time they would settle on surfaces and become a hazard and cleaning burden.
The IMP 38 is a cleaver electrostatic air cleaner that is made by Trion, and which is designed to connect to pipelines that carry oil mist from engines or indeed any other lubricated and enclosed machine. The IMP 38s come do not have a fan as they rely on the airflow that pre exists in the pipeline. As the mist enters the cleaner the spiked ioniser section gives each oil droplet charge, so that as it then flows through an array of oppositely charged collector plates there is an attraction between the charged oil mist droplets and the collector plates. In short the oil droplets hit the plate and the collected oil drains off under gravity back to the pipe and the sump. IMP 38 comes in various sizes with airflow capacity ranging up to 1020m3/hr and with plain, threaded or flanged pipe connections to make connection to the various pipe sizes easy.
IMP 38s electrostatic oil mist eliminator have almost no pressure drop so they have no impact to speak of on the efficiency of the engine. Moreover, they are well specified, meeting stringent requirements of military specifications MIL-S-901D, MIL-STD-167, MIL-STD-461, covering high impact shock, environmental vibration , and electromagnetic interference.
On engines burning cleaner fuels IMP 38s should run for long periods with little maintenance returning oil back to the sump, however the heavier and dirtier the fuel type, the more often the collector cells in the units will need to be cleaned.
Of course marine engines are only one application for IMP 38s – they are also used for gas turbines, auxiliary engines, large compressors, storage tanks, and vacuum pumps.
For more information and help on these oil mist problems call us 01729 824108. All we need is the pipe size, airflow through the pipe and your preferred connection detail and we can specify the ideal IMP38 for your application.
Visit the Puravent website for more information on Oil Mist Eliminator for Marine Engine Breathers