SCOTCH BOILER



• The main components of a Scotch boiler consist of a cylindrical shell containing the furnaces; these are about 1m in diameter, the number depending upon the boiler diameter. 

• Two furnaces are usually titted for boiler shell diameters up to 4 m, while three furnaces are titted for diameters greater than this. 
• The fuel is burnt in these water cooled furnaces, constructed in the form of corrugated cylinders. 

• After leaving the furnace the hot gases enter the combustion chamber; this is also surrounded by water and so again provides for the generation of steam.

• From the combustion chamber the gases pass through smoke tubes, which consist of plain and stay tubes-the latter being necessary to support the flat tube plates.

• After leaving the tubes, the gases enter the smoke box, and then the uptakes. In many cases gas/air heaters are fitted to increase the boiler efficiency.

• As the boiler has a considerable amount of flat surface subjected to pressure, an elaborate system of stays is required. Large steam space stays support the upper parts of the flat end plates, while stay tubes and combustion chamber stays support the mid-section of the back plate, the tube plates, and combustion chamber.

• Internal access to the boiler is provided by means of a top manhole in the shell, and by lower manholes cut in the front end plate.
The Scotch boiler is a strong robust type of boiler capable of operating with poor quality feed water, and only requires an open feed system.

• It contains large amounts of water and provides a reservoir of steam, which makes it suitable for the supply of considerable amounts of steam for auxiliary purposes.

• However, the large quantity of steam and water contained in the boiler introduces ahazard in that, in the event of failure of tubes, etc., large amounts of water and steam can enter the boiler room.

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