Fuel dribble (dripping) after injection

This occurs when the fuel supply is not precisely cutoff at the end of fuel injection and fuel particles are accumulated on the tip of the nozzle. If fuel dribble occurs after fuel injection, the fuel in the cylinder will not burn completely. This will result in the emission of black or white smoke being exhausted. To prevent fuel dribble, the relief valve of the delivery valve is designed to draw back any fuel that may drip out of the nozzle after injection. Fuel dribble occurs if there is any failure in the delivery valve or injection nozzle, as the residual pressure remains in the injection pipe after fuel injection.

Chemical Tankers

The structural configuration and arrangements of chemical tankers often are basically similar to those described for oil tankers. For some chemical tankers, however, arrangements may also include a double bottom in way of cargo tanks, a double skin construction or deck cofferdams or any combination of these. Certain more hazardous cargoes may also require tanks which are separate from the hull structure or are to be so installed that the tank structure is not subject to major hull stresses. In the latter cases the scantlings and arrangements may be similar to ships carrying liquefied gases.