A Manual of Locomotive Engineering: With an Historical Introduction : a ... by William Frank Pettigrew

Author:William Frank Pettigrew
Language: eng
Format: epub
Publisher: C. Griffin
Published: 1899-03-25T05:00:00+00:00

o

s

I

CO

P4

J

pa

O

6

3

Ashpan and Dampers. —The ashpan is placed below and is well ^xed to the bottom of the firebox. It is furnished with movable doors or dampers worked from the footplate for regulating the air supply, and collects all the ashes that pass through the firebars, and prevents them from falling upon the line. The dampers must make an air-tight fit with the ashpan, so that the grate may be -completely closed from the outside air; that this should be possible when the engine is standing is most important.

The dampers are placed on some engines at both back and front of the ashpan—as shown at D^, D^ Plate I.—^but sometimes only in front; and can be opened or closed to admit, or keep out, air as the engine-driver considers necessary.

The sides and bottom of the ashpan are made of |-inch or y'^^inch wronght-iron or mild steel plates, which may be rivetted to angle-irons 2 ins. by 2 ins. by ^ in., or may be fianged from a single plate.

Chimney.—There are numerous forms in which chimneys may be made, but they are generally conical—slightly smaller in diameter at the bottom than at the top. The inside diameter of the chimney is a matter of the greatest importance. It is usually made about 2 ins. less than that of the cylinders. Thus, when the diameter of the cylinders is from 17 ins. to 18 ins., that of the chimney may be 14 ins. at the bottom and 16 ins. at the top; although these dimensions are commonly diminished if the engine will not steam well. The chimney area is sometimes made 12 times that of the blast •oritice, and -^^ of the grate area. The length of the chimney is dependent on the diameter of the wheels and size of the boiler, the height of top of chimney being given from the rail level, according to the construction gauge of the road.

Chimneys are made of either wrought iron or mild steel plate, f-in. thick, or of cast iron. The base of the chimney is dished, the object being to make the opening in the top of the smokebox as large as possible. This, in large engines, is from 1 ft. 10 ins. to 2 ft. in diameter. In America and on the Continent, for wood burning and other purposes, chimneys are made of different shapes and forms, and are fitted with valves, cones, and deflectors. The •chimney is frequently prolonged downwards towards the interior of the smokebox in the form of a cone.

Blast Pipe. —The blast pipe is usually made of cast iron or copper.

With the locomotive boiler it is necessary to have rapid combustion, and for this, as it is possible to have only short chimneys, the natural draught is altogether insufi&cient. This insufficiency of the natural draught led to the use of the blast pipe. The exhaust steam as it leaves the cylinders passes through the blast pipe and op the chimney, where, expanding, it fills the chimney like a piston or plunger.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.