Marine solutions

SULZER MAN Crosshead bearing surface area is smaller Large crosshead bearing surface area Bearing shell is smooth surface Grooves with machined channel to retain lubricating oil The lube oil is supplied by separate crosshead pump The lube oil is supplied by same main lube oil system pump The lube oil pressure is maintained at 12-16 bar The oil pressure is maintained at 2-4 bar i.e. system pressure Lube oil is injected once in one cycle @ 20 deg. Before TDC Injected twice every engine cycle Lube oil is supplied to crosshead by means of swinging or articulated pipe at crosshead Lube oil is supplied to crosshead by means of telescopic pipe connected to the guide

Crosshead is attached on the upper part of the connecting rod, which connects the con-rod to the piston rod. The guide and the guide shoe runs on the guide rail to support the crosshead pin and to transfer the side thrust of the crosshead to the engine frame. In some old MAN B&W engines and SULZER RND engines, the piston rod passes through a bore in the crosshead and is bolted from the bottom by means of fine threaded nut. In the new design engines such as MAN SMC/ ME and SULZER RTA/ RT flex, the pison rod palm rests on the crosshead flat surface and four hydraulic bolts are used to tie them together. Guide and guide shoe, along with the connecting rod and crosshead, is an important arrangement as the guide directs the guide shoe in reciprocating direction while absorbing the side thrust produced during the motion of the connecting rod. The guide comprises of guide rail (normally integrated/ bolted with the frame) and guide plates, in which, the guide shoe moves up and do

The  tie rods on a 2 stroke marine diesel engine hold the components of the engine together in compression and transmit the firing loads to the bedplate. Breakage, usually due to a fatigue fracture, can be caused by incorrect tightening, misalignment between the mating surfaces, overloading of the engine etc. Sods law dictates that often the bolt will fail at mid length. The top half can be removed by lifting it out, however the removing the bottom half will present a challenge, due to the restriction in headroom in the crankpit. Broken tie bolt (above) and right, detail of fatigue fracture. The most obvious method of removal may seem to be to cut the tierod out in small pieces using a grinding wheel/ burning gear. This is not recommended. Two alternatives are available: The first involves passing a wire loop down the tierod tube to the bottom of the tiebolt and lifting the bolt out. The second method outlined below involves jacking the bolt out from below. I

Land-based Installations On land based electrical systems, such as those found in homes and factories, the neutral wire (or phase) is connected to the ‘Earth’. The Earth wire is a safety feature that allows the safe direction of ‘fault currents’ into the ground, and away from people and livestock. As electricity will travel along the easiest ‘path’, the earth connection provides this. If a piece of equipment with a metal case did not have an adequate earth, and a fault caused the casing to become ‘live’, then the electricity would travel through a person touching the case. This is because the human body will conduct electricity (it is very moist). The electricity therefore will use the persons body as a low resistance path between the ‘live wire /or casing’ , and the earth (ground). Just to be clear about this, what is happening is that the electricity is in effect using the body as a conductor, similar to a wire. The above scenario is not good for the human body, and a

*Circuit breakers. *Fuses *Over current relay *Dead front panel *Rubber insulation mat *Insulation resistance *Reverse power trip *Ebonite Handel *Earth fault lamp *Under voltage trip *Over voltage trip *Preferential trip

Hot corrosion             It is basically vandium corrosion. Vanadium is present in fuel oil,when vandium and sodium is present in a ratio of 1:3 vanadium pentoxide a hard component is formed whose melting point is 630°. Due to high temperature in combustion chamber these melts into metal surface and leaving the surface exposed to corrosion is called as hot corrosion. Cold corrosion           Cold corrosion occur due to presence of sulphuric acid inside liner surface. This abnormal corrosion can cause wear and tear inside liner. This occurs due to new regulations that engine should be operated at high pressure and low temperature. This temperature below due point will result in deposit of water droplets inside liner surfaces and this water combine with sulphur in fuel to form sulphuric acid.

Main bearing           It is measured between journal pin and top shell when the piston is at any convenient position. Crosshead bearing           It is measured between top shell and crosshead pin, piston should be at 45° aftrr TDC. GUIDESHOE CLEARANCE             Measured between GUIDESHOE and guide bar. Bottom end bearing             Measured between bottom shell and con rod. Piston should be at BDC.     NOTE ALL CLEARANCE SHOULD BE BETWEEN 0.25-0.4MM