Frequently asked questions:

1. Why should I protect my engine with an Oil Mist Detection system instead of main bearing temperature control or other equivalent devices as mentioned by SOLAS regulations?

With main bearing temperature control, you detect the main bearings only. A single Oil Mist Detection system can protect main bearings, big end bearings, pigeons, cylinder liners, pistons, crosshead (2-stroke), on some engines even the camshaft with its bearings, shortly spoken all moving parts inside the engine where surfaces are gliding. Also the so called ‘equivalent devices (SOLAS)’ on the market so far are far not able to offer a protection and versatibility, an Oil Mist Detection system does.

2. What engine sizes should be protected by an Oil Mist Detection system against Crankcase explosions?

The SOLAS regulations, fire precautions regulates that Marine Diesel engines from 2250 kW or cylinder bore <300 mm have to be protected against crankcase explosions by a) an Oil Mist Detector, b) main bearing temp. control devices or c) equivalent devices.

As no relevant regulations are existing for the same engine types and sizes to be used in power plants, cases are known of crankcase explosions with bad consequences for men and material. Following SCHALLER Automation’s experience, more and more engine manufacturers are deciding to offer Oil Mist Detection systems to protect their engines from sizes around 900 kW and 160 mm cylinder bore.

3. Engines of what make are protected by SCHALLER Oil Mist Detectors?

Schaller Automation, since 1976, has delivered more than 55,000 oil mist detectors worldwide. Every year, approximately 1900 new oil mist detectors are being installed on engines.

  • MAN B&W AG
  • Deutz
  • Caterpillar MaK
  • DMR Diesel Motorenwerke Rostock
  • SKL
  • MBH Maschinenbau Halberstadt GmbH
  • Wärtsilä NSD Winterthur (two and four stroke engines)
  • Cummins Wärtsilä (former SACM)
  • SEMT Pielstick
  • NSD Sulzer France (company is now Wärtsilä NSD)
  • Stork Wärtsilä
  • MAN B&W AS Copenhagen (two stroke engines)
  • MAN B&W Holeby (four stroke engines)
  • MAN B&W Alpha (two and four stroke engines)
  • Ulstein Bergen (now Rolls Royce Marine Engines)
  • Wärtsilä Wichmann
  • Wärtsilä Nohab
  • Wärtsilä NSD Corp. (Vaasa 32, and W46)
  • Ruston GEC Alsthom (now MAN)
  • Mirrleess Blackstone (now MAN)
  • ZGODA (NSD ZAL40 and ZAV40 engines)
  • HCP Cegielski (MAN B&W and Sulzer two and four stroke license engines)
  • Gdynia Shipyard (two stroke engines)
  • Stocznia Szczecinska (two stroke engines)
  • Russkiy Diesel (Pielstick license four stroke engines)
  • Bryansk Diesel (MAN B&W two stroke license engines)
  • Grandi Motori Trieste (two and four stroke Sulzer, Wärtsilä engines)
  • Brodosplit (two stroke MAN B&W and NSD Sulzer license)
  • 3 Maj Shipyard (two stroke NSD Sulzer license)
  • Uljanik (two stroke MAN B&W and NSD Sulzer license)
  • BAZAN Motores, Cartagena (four stroke MAN, Caterpillar license)
  • Echevarria Wärtsilä (four stroke license engines)
  • Manises Diesel Engine SA (two stroke MAN B&W license)
  • Caterpillar Inc.
  • Mitsubishi (two and four stroke engines)
  • Diesel United (two and four stroke engines)
  • Kawasaki Heavy Industries (two and four stroke engines)
  • Hitachi Heavy Industries (two and four stroke engines)
  • Niigata (four stroke engines)
  • Mitsui (two stroke MAN B&W and NSD Sulzer license)
  • Yanmar (four stroke engines)
  • Daihatsu (four stroke engines)
  • Hyundai Heavy Industries (two and four stroke engines)
  • Korea Heavy Industries Co. (two and four stroke engines)
  • Samsung Heavy Industries (two and four stroke engines)
  • SsangYong Heavy Industries (two and four stroke engines)
  • Hudong Shipyard (two stroke MAN B&W and NSD Sulzer license)
  • Shanghai Shipyard (two stroke MAN B&W and NSD Sulzer license)
  • Yichang Motor Division (two stroke MAN B&W and NSD Sulzer license)
  • Dalian Marine Diesel (two stroke MAN B&W and NSD Sulzer license).

4. What is oil mist?

The atmosphere in the crankcase contains a large amount of relatively large oil droplets (200 micron) in warm air. Because of the droplets small surface area to volume ratio, the possibility of ignition by a heat source is very low. Oil Mist is formed when a moving part inside the engine fails, it then overheats and vaporizes the oil droplets, which will travel away from the hotspot and condense into much smaller droplets reduced down to 5- 10 microns.

Oil mist becomes ignitable whenever it reaches the Lower Explosion Level (LEL), which is approximately 48mg/liter or 13% oil mist / air ratio. At this point any hot spot with temperature above 850oC can trigger an explosion.

Surfaces that can generate intensive oil mist in addition to the crankshaft bearing system include:

  • – Pistons in cylinder liners
  • – Crankshaft bearings such as main bearings and big-end bearings
  • – Camshafts, their bearings and cams
  • – Timing gear shafts and their bearings
  • – Gear boxes with their bearings, and in some cases pumps
  • – Guide blocks and paths in cross-head engines