Boiler Accessories Boiler Setting

The smoke box projects over the front end of the boiler and has a rectangular uptake.

Fig. 3 shows the top view of the same boiler.

The front is usually of cast iron, with doors for firing and cleaning and for access to the tubes. Soot, dirt, etc., are removed through the door in the brickwork at the rear.

The end which contains the handhole should be set about one inch lower than the other end, so that the sediment and detached scale will tend to accumulate there.

Internally-fired boilers may also be enclosed in brickwork. The setting is a support and covering, forming the side flues but not the furnace. Excess of brickwork surface in contact with the shell, should be avoided, as brickwork collects moisture, which causes external corrosion.

Water-Tube Boilers. The settings for water-tube boilers are similar to the settings of cylindrical tubular boilers. Marine watertube boilers are enclosed in sheet-iron casing, which is lined with nonconducting material, usually asbestos or m agnesia.

Supports. There are, as already intimated, two common methods of supporting boilers-1. By means of brackets; 2. By suspending from wrought-iran beams.

If the boiler is about 15 feet long, it is customary to use two brackets on each side. If more than 15 feet, three on each side are used. The front brackets rest on the brickwork, but the others rest on small iron rollers to allow for expansion. Brackets are so arranged that the plane of support will be a little above the middle. There are several forms of brackets. The form shown in Fig. 4 is usually made ofcast iron, and is provided with rivets above the flange of the bracket.

It is better to have the rivets both above and below the flange, as shown in Fig. 5.

Fig. 6 shows one method of suspending from beams. A lug, made of wrought iron, is riveted to the plates of the boiler. A bolt having one end bent like a hook, holds the lug from the beam. In Fig. 7 the lug is replaced by a loop of wrought iron. Fig. 8 shows another method of suspension, the connection between the rod and the boiler-plates being short pieces of boiler-plate arranged for flexibility.

When the boiler is of small diameter, it may be suspended as shown in Fig. 9.