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General Requirements for Construction of Boilers

steam and supply

GENERAL REQUIREMENTS FOR CONSTRUCTION OF BOILERS When we know these facts we design our boiler so as to have: 1. Sufficient area of grate to burn the required amount of fuel under the given draft.

2. Enough heating surface to absorb the heat of combustion.

3. Combustion chamber and flue area large enough to completely burn and carry off the products of combustion.

4. Water space sufficiently large so that a sudden demand will not cause too great a variation in water level.

5. Surface of water large compared to volume, in order that steam may be rapidly disengaged.

6. Steam space large enough to supply an irregular demand without causing a great change of pressure.

7. Steam outlet large enough to supply steam to the engine without wire-drawing.

If the outlet is not sufficiently large to supply plenty of steam, the demand will be greater than the supply and the steam will be throttled or wire-drawn, that is, it will lose some pressure.

For all common types of boilers, the proportions between the above requisites have been determined by experiment and mathematics. These relations, with simple calculations and good judgment on the part of the designer, are all that are needed for this work.