Improvements in and connected with Multi-tubular Boilers.
Year: 1894

page_text: Date of Application, 21st June, 1894-Accepted, 11th Aug., 1894
COMPLETE SPECIFICATION.
Improvements in and connected with Multi-tubular Boilers.
I, JAMES ANGUS, of 65, Catford Hill, London, C.E., do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
This invention relates to locomotive, stationary, marine, portable, and other
steam engines which are fitted with multi-tubular boilers, and has for its object,
Firstly. To allow a free exhaust from the cylinders.
Secondly. To effect a considerable economy in the consumption of fuel.
Thirdly. To prevent the emission of live cinders and sparks from the chimney of
the engine.
Fourthly. To obtain more perfect combustion in the lower tubes of the boiler.
In order to carry out my invention I dispense with the conoidal blast nozzle and
contracted blast orifice in the delivery end of a blast pipe as at present employed,
and substitute therefor a blast pipe having a blast orifice equal in area to twice the
area or about twice the area of the two exhaust steam pipes, thus allowing a free
exhaust from the cylinders.
I then form an annular or other conveniently shaped air space or chamber round
the upper portion of such blast pipe, by extending the base of the chimney into the
smoke box so that it surrounds such upper portion, and descends a sufficient distance
below the top of the blast pipe to produce the required blast without impeding the
free action of the upper tubes. The air space or chamber thus formed operates in
a similar manner as the conoidal nozzle and contracted blast orifice before referred
to, by creating a vacuum, or partial vacuum, in the smoke box, which vacuum, or
partial vacuum, is caused by the suction produced by such air space or chamber, as
indicated by the arrows in the accompanying drawing; at the same time that all
throttling of the steam is avoided and a free exhaust is allowed thereto, thereby
relieving the cylinders from back pressure and so obtaining more effective results
from the engine combined with a diminished consumption of fuel.
In order to prevent the emission of live cinders and sparks from the chimney of
the engine and so minimise the risk of fires outside the railway fences, and in farm
yards, corn fields, and other places where steam engines are employed, I fit the base
of the extension plate forming the air space or chamber with a wire screen, which
intercepts the live cinders and sparks that would otherwise be carried into such
space or chamber by the force of the air current, and thence up through and out of
the chimney.
In order to obtain more perfect combustion in the bottom rows of tubes I form a
blow pipe at the lower end of the blast orifice at the point of intersection of the two
exhaust steam pipes. Such blow pipe extends downwards to about the third row of
bottom tubes and is fitted at its base with a wire screen to prevent cinders and other
impedimenta being drawn in. A steam jet is fitted into such blow pipe near its
upper end which steam jet acts as an ejector and serves in combination with the
blow pipe to promote combustion and increase the effective operation of the lower
series of tubes and to effect a further economy in the consumption of fuel.

page_text: height in itself such extension piece is dispensed with. e, extension of chimney base
into smoke box in order to form the air space or chamber. screen fitted to the
base of auch extension. 4, blow pipe fitted with screen plate i. k, steam jet which
ncts as an ejector.
I would here observe that 1 make no claim to the extension of the base of the
chimney into the smoke box as being novel in itself but only in combination with
my improved construction and arrangement of blast pipe. My invention can be
readily adapted to any existing multi-tubular boiler at a trifling cost as no alteration
of the diameter of the chimney is required.
If desired the blow pipe and steam jet arrangement may be dispensed with thus
reducing the cost of applying my invention to existing engines, but in this case the
nction of the lower tubes will remain in its present imperfect condition.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed declare that what I
claim is
1°. In a multi-tubular boiler a blast pipe having at its delivery end a blast orifice
equal in aren to twice the area or about twice the area of the two exhaust steam
pipes, and placed in an annular or other conveniently shaped air space or chamber
formed by extending the base of the chimney into the smoke box all substantially
as hereinbefore described and shewn.
20. In combination with any improved construction and arrangement of blast
pipe fitting the base of the chimney extension hereinbefore described with a screen
plate for the purpose of intercepting live einders and sparks and thus preventing the
occurrence of fires all as hereinbefore specified.
3°. In a multi-tubular boiler fitting the lower end of the blast orifice with a blow
pipe and steam jet all substantially in the manner hereinbefore described and
shown.
4°. Fitting the blow pipe hereinbefore described and claimed with a screen plate
in the manner hereinbefore specified.
El & Co.,
JAMES ANGUS.
33, Southampton Buildings, London, Agents for Applicant.