Machinery Spaces
Home || Diesel Engines ||Boilers||Feed Systems ||Steam Turbines ||Fuel Treatment ||Pumps ||Refrigeration ||

Explosion Relief Valve for Marine Diesel Engine

The diesel engine is a type of internal combustion engine which ignites the fuel by injecting it into hot, high-pressure air in a combustion chamber. In common with all internal combustion engines the diesel engine operates with a fixed sequence of events, which may be achieved either in four strokes or two, a stroke being the travel of the piston between its extreme points. Each stroke is accomplished in half a revolution of the crankshaft.

As a practical safeguard against explosions which occur in a crankcase, explosion relief valves or doors are fitted. These valves serve to relieve excessive crankcase pressures and stop flames being emitted from the crankcase. They must also be self closing to stop the return of atmospheric air to the crankcase.

ships machinery spaces
container ships machinery info
Various designs and arrangements of these valves exist where, on large slow-speed diesels, two door type valves may be fitted to each crankcase or, on a medium-speed diesel, one valve may be used. One design of explosion relief valve is shown in Figure. A light spring holds the valve closed against its seat and a seal ring completes the joint.

A deflector is fitted on the outside of the engine to safeguard personnel from the outflowing gases, and inside the engine, over the valve opening, an oil wetted gauze acts as a flame trap to stop any flames leaving the crankcase. After operation the valve will close automatically under the action of the spring.

Explosion relief valve

Fig : Explosion relief valve


Marine diesel engine related other useful articles:
  1. Four stroke cycle diesel engines operational guideline

    2. The four-stroke cycle is completed in four strokes of the piston, or two revolutions of the crankshaft. In order to operate this cycle the engine requires a mechanism to open and close the inlet and exhaust valves
    More .....

  2. Two stroke cycle diesel engines operational guideline

    3. The two-stroke cycle is completed in two strokes of the piston or one revolution of the crankshaft. In order to operate this cycle where each event is accomplished in a very short time, the engine requires a number of special arrangements.
    More .....

  3. Power measurement for marine diesel engine - The engine indicator

    4. There are two possible measurements of engine power: the indicated power and the shaft power. The indicated power is the power developed within the engine cylinder and can be measured by an engine indicator. The shaft power is the power available at the output shaft of the engine and can be measured using a torsionmeter or with a brake.
    More .....

  4. Supply of fresh air and removal of exhaust gases by a gas exchanger

    5. A basic part of the cycle of an internal combustion engine is the supply of fresh air and removal of exhaust gases. This is the gas exchange process. Scavenging is the removal of exhaust gases by blowing in fresh air.
    More .....

  5. The fuel oil system for a diesel engine

    6. The fuel oil system for a diesel engine can be considered in two parts—the fuel supply and the fuel injection systems. Fuel supply deals with the provision of fuel oil suitable for use by the injection system.
    More .....

  6. Lubricating oil system for a marine diesel engine - how it works

    7. The lubrication system of an engine provides a supply of lubricating oil to the various moving parts in the engine. Its main function is to enable the formation of a film of oil between the moving parts, which reduces friction and wear. The lubricating oil is also used as a cleaner and in some engines as a coolant.
    More .....

  7. Cooling of ships engine - how it works , requirement of fresh water & sea water cooling system

    8. Cooling of engines is achieved by circulating a cooling liquid around internal passages within the engine. The cooling liquid is thus heated up and is in turn cooled by a sea water circulated cooler. Without adequate cooling certain parts of the engine which are exposed to very high temperatures, as a result of burning fuel, would soon fail.
    More .....

  8. Starting air system for diesel engine - how it works

    9. Diesel engines are started by supplying compressed air into the cylinders in the appropriate sequence for the required direction. A supply of compressed air is stored in air reservoirs or 'bottles' ready for immediate use. Up to 12 starts are possible with the stored quantity of compressed air.
    More .....

  9. Governor-Function of governors controlling speed of marine diesel engine

    10. The principal control device on any engine is the governor. It governs or controls the engine speed at some fixed value while power output changes to meet demand. This is achieved by the governor automatically adjusting the engine fuel pump settings to meet the desired load at the set speed.
    More .....

  10. Cylinder relief valve of a marine diesel engine - operational guideline

    11. The cylinder relief valve is designed to relieve pressures in excess of 10% to 20% above normal. The operation of this device indicates a fault in the engine which should be discovered and corrected.
    More .....

  11. Explosion relief valve of a marine diesel engine

    12. As a practical safeguard against explosions which occur in a crankcase, explosion relief valves or doors are fitted. These valves serve to relieve excessive crankcase pressures and stop flames being emitted from the crankcase. They must also be self closing to stop the return of atmospheric air to the crankcase.
    More .....

  12. Turning gear operational guideline
    The turning gear or turning engine is a reversible electric motor which drives a worm gear which can be connected with the toothed flywheel to turn a large diesel. A slow-speed drive is thus provided to enable positioning of the engine parts for overhaul purposes.
    More .....

  13. Couplings, clutches and gearboxes of a marine diesel engine

    14. The principal control device on any engine is the governor. It governs or controls the engine speed at some fixed value while power output changes to meet demand. This is achieved by the governor automatically adjusting the engine fuel pump settings to meet the desired load at the set speed.
    More .....

  14. MAN B&W diesel engine - Basic principles and operational guideline

    15. It is one of the MC series introduced in 1982, and has a longer stroke and increased maximum pressure when compared with the earlier L-GF and L-GB designs.
    More .....

  15. Crankcase oil mist detector of a marine diesel engine

    16. It is one of the MC series introduced in 1982, and has a longer stroke and increased maximum pressure when compared with the earlier L-GF and L-GB designs.
    More .....

  16. Various Heat exchanger for running machinery on board cargo ships

    17. Shell and tube heat exchangers for engine cooling water and lubricating oil cooling have traditionally been circulated with sea water. The sea water is in contact with the inside of the tubes, tube plates and water boxes.
    More .....

  17. Guideline for Turbochargers safety and operational requirement

    18. Shell and tube heat exchangers for engine cooling water and lubricating oil cooling have traditionally been circulated with sea water. The sea water is in contact with the inside of the tubes, tube plates and water boxes.
    More .....

  18. Function of Piston & piston rings

    19. Piston forms the lower part of the combustion chamber. It seals the cylinder and transmits the gas pressure to the connecting rod. The Piston comprises of two pieces; the crown and the skirt.The crown of a piston is subject to mechanical and thermal stresses.
    More .....



Marine machineries - Useful tags

Marine diesel engines ||Steam generating plant ||Air conditioning system ||Compressed air ||Marine batteries ||Cargo refrigeration ||Centrifugal pump ||Various coolers ||Emergency power supply ||Exhaust gas heat exchangers ||Feed system ||Feed extraction pump || Flow measurement || Four stroke engines || Fuel injector || Fuel oil system || Fuel oil treatment ||Gearboxes || Governor || Marine incinerator || Lub oil filters || MAN B&W engine || Marine condensers || Oily water separator || Overspeed protection devices || Piston & piston rings || Crankshaft deflection || Marine pumps || Various refrigerants || Sewage treatment plant || Propellers || Power Plants || Starting air system || Steam turbines || Steering gear || Sulzer engine || Turbine gearing || Turbochargers || Two stroke engines || UMS operations || Drydocking & major repairs || Critical machinery || Deck machineries & cargo gears || Control and instrumentation ||Fire protection ||Engine room safety ||





Machinery Spaces.com is about working principles, construction and operation of all the machinery items in a ship intended primarily for engineers working on board and those who working ashore . For any remarks please Contact us

Copyright © 2010-2016 Machinery Spaces.com All rights reserved.
Terms and conditions of use
Read our privacy policy|| Home page||