IMPROVEMENTS IN STEAM BOILERS, AND IN MECHANICAL STOKING APPARATUS
Year: 1882

page_text: LETTERS PATENT to George Sinclair, of Leith, in the County of Mid Lothian,
North Britain, for an Invention of "IMPROVEMENTS IN STEAM BOILERS, AND
IN MECHANICAL STOKING APPARATUS."
"6
PROVISIONAL SPECIFICATION left by the said George Sinclair at the Office
of the Commissioners of Patents on the 10th August 1882.
GEORGE SINCLAIR, of Leith, in the County of Mid Lothian, North Britain,
IMPROVEMENTS IN STEAM BOILERS AND IN MECHANICAL STOKING APPARATUS
"
This Invention comprises further developments of or improvements on the
Inventions described in the Specifications of Letters Patent obtained by the
present applicant and having the official numbers 2004 of 1877, 1388 of 1878, and
2035 of 1880.
One of the present improvements is applicable to steam boilers having internal
furnaces and used for either stationary or marine purposes; and the object is to
diminish or prevent injury often caused by strains due to the upper parts of the
boilers becoming heated whilst the bottom parts are still cold; and the improve-
ment consists in forming in the lower parts of the outer shell of the boiler and also
in the lower parts of the internal flues or furnace shells, one or more indentations
or corrugations, extending transversely or at right angles to the length of the
boiler. With such indentations or corrugations the lower parts of the boiler will
be able to extend sufficiently along with the upper parts when the latter are
expanded by heat so as to avoid or very much diminish the strains that 'would
otherwise be produced. When the shell of the boiler or furnace flue is of a
thickness of metal rendering the formation of the indentations or corrugations
difficult, the shell may be made of two thicknesses of thinner metal, in which the
indentations or corrugations can be separately made, and when two thicknesses
are used in this way the indentations may be towards opposite sides so that the
cavities formed face each other.
The present improvements in the mechanical stoking apparatus consist principally
in constructing the front of each furnace with an open frame or with openings
n
1

page_text: between the front ends of the fire bars and the coal supplying hopper above, and in
fixing on the inner side of the said open frame a frame holding firebricks which
project a short distance into the furnace. These firebricks are formed with holes
or passages through them or with channels along their sides to form passages
between them for the entrance of air; and the inner ends of the firebricks
becoming strongly heated heat the entering air and thereby improve the combustion
of the coal. The cross bearer of the front ends of the firebars is adjustable in
height by means of screws, so that if required with any particular kind of coal space
may be made for the admission of some air between the fire bars and the firebricks
in addition to the air passing through the firebricks.
"
'
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Sinclair in the Great Seal Patent Office on the
5th February 1883.
GEORGE SINCLAIR, of Leith, in the County of Mid Lothian, North Britain,
"IMPROVEMENTS IN STEAM BOILERS AND IN MECHANICAL STOKING APPARATUS"
My said Invention has for its object to simplify and otherwise improve the
construction of mechanical stoking apparatus in order to render the same more
efficient and suitable for different kinds of coal and comprises further developments
of or improvements on the Inventions described in the Specifications of Letters
Patent obtained by the present applicant and having the official numbers 2004 of
1877, 1388 of 1878, and 2035 of 1880.
The improved apparatus for each furnace comprises a hopper from the bottom
of which a reciprocating pusher box or pusher pushes the coals gradually into the
furnace. The fire bars, which are by preference of an improved construction
hereinafter described are made to reciprocate longitudinally by a shaft having a
number of cranks on it, and their inner ends are a little above a transverse water
casing, the firebridge being at some distance inwards from the ends of the fire bars.
These and certain improved details also comprised in my said Invention will be
best understood from the following particular description aided by the accompanying
explanatory drawings.
Figures 1, and 2, are a longitudinal vertical section and an end elevation of a
horizontal cylindrical steam boiler constructed with two internal furnaces; and
figures 3, 4, and 5, are different views of the improved compound fire bar. Figures 6,
7, and 8, are vertical sections showing an improvement in boilers having internal
furnaces. In these drawings the same reference numerals are used to mark the
same or like parts wherever they are repeated.
Each compound fire bar, 6, consists of three pieces, shown combined and in plan
in figure, 3, there being two side pieces, 6, having straight outer sides, and a middle
piece, 7, which is made with lateral inclined projections. Figure, 4, is a side view

page_text: of the middle piece, 7, and figure, 5, is a side view of the outer side of one of the
side pieces, 6. The inner sides of the pieces, 6, are made counterparts of the sides
of the middle piece, 7, but so that when the pieces are combined there is a narrow
space for the passage upwards of air between the middle piece, 7, and the side
pieces, 6. My improved compound bar has no external lateral projections which
might interfere with the different longitudinal movements of adjacent compound
bars, whilst at the same time each compound bar has within it openings of a zig-
zag or analogous form which are believed to be the best for the passage of air to the
fuel. A double-incline projection, 8, is formed on the under side of the fire bars
near their inner ends for the purpose of making them rise and fall a little when
their longitudinal movements cause the projection, 8, to ride over their inner
transverse bearer, 9. Immediately behind the inner transverse bearer, 9, there is a
transverse water casing, 10, communicating with the boiler at the two sides of the
furnace; and the firebridge, 11, is placed at some distance further back leaving a
space, 12, into which the more or less consumed fuel descends as it gradually passes
beyond the inner end of the fire bars, 6, in consequence of their reciprocating action
combined with the continual addition of fresh fuel at the front or outer end of the
furnace.
The front ends of the fire bars, 6, are supported by and move upon a transverse
bearer, 13, the height of which is adjustable by means of screws in the brackets, 14,
by which it is held. The reciprocating motion is imparted to the fire bars, 6, by
connecting rods, 15, jointed to the bars at their inner ends, and at their outer ends
jointed upon cranks on a shaft, 16, carried by standard bearings, 17, and driven by
means of a spurwheel and pinion, 18, from a first-motion shaft, 19, having on it a
pulley, 20, for a driving belt, and provided with an engaging and disengaging
clutch. Just above the space that the front ends of the fire bars work through,
there is fixed an open frame, 21, having immediately above it a plate, 22, on which
there is a movable pusher, 23; and this pusher is connected by a pair of adjustable
rods, 24, to upright pieces, 25, fixed or formed on two of the fire-bar connecting
rods, 15. The outer ends of the pusher rods, 24, are also connected to the rods, 15,
by inclined links, 26, and in consequence of these connections the pusher, 23,
moves backwards and forwards as the crank shaft, 16, rotates. The hopper, 27, in
which the coal is put is made with inclined sides and front, and is fixed directly
over the plate, 22, and pusher, 23, its bottom being open towards the interior of
the furnace; and the coals fall from it down upon the plate, 22, and are gradually
pushed into the furnace by the reciprocating action of the pusher, 23. In each
hopper, 27, there is fixed an iron box, 28, made with a pointed top to cause the
coals to be divided towards each side of it as they descend. This box, 28, is open
at its lower inner end, and at its front part it is closed by a movable plate having
perforations through which the fireman can see the condition of the fire, whilst
should it ever be necessary he can remove the perforated plate and introduce a rod
or poker. At the inner side of the open frame, 21, which is between the bottom
plate, 22, of the hopper and the fire bars, there is fixed a frame, 29, holding
firebricks, 30, which project into the furnace, and which are made with holes
5 through them or with channels along their sides to form passages for the entrance
of air. The inner ends of the firebricks, 30, become intensely hot and the air
entering through them is heated and acts in an improved manner in promoting
combustion and in preventing the formation of clinker or the agglomeration of
certain kinds of coal. If with any coals more air is required than what passes
0 through the firebricks, 30, the front transverse bearer, 13, of the fire bars, 6, may be
lowered a little to allow air to enter under the firebricks, 30.
One of my present improvements is applicable to steam boilers having internal
furnaces and used for either stationary or marine purposes; and the object is to
diminish or prevent injury often caused by strains due to the upper parts of the
5 boilers becoming heated whilst the bottom parts are still cold; and the improve-
ment consists in forming in the lower parts of the outer shell of the boiler and
also in the lower parts of the internal flues or furnace shells, one or more

page_text: indentations or corrugations, extending transversely or at right angles to the
length of the boiler. With such indentations or corrugations the lower parts of
the boiler will be able to extend sufficiently along with the upper parts when the
latter are expanded by heat so as to avoid or very much diminish the strains. that
would otherwise be produced. This improvement is shown in transverse and
longitudinal vertical section in figures, 6, and 7. When the shell of the boiler or
furnace flue is of a thickness of metal rendering the formation of the indentations
or corrugations difficult, the shell may be made of two thicknesses of thinner
metal, in which the indentations or corrugations can be separately made; and
when two thicknesses are used in this way the indentations may be towards
opposite sides so that the cavities formed face each other as shown in figure, 8.
Having thus particularly described my said Invention and the manner of
performing the same I have to state that I do not restrict myself to the precise
details herein described or delineated but that what I believe to be novel and
original and claim as the Invention secured to me by and in terms of the herein-
before in part recited Letters Patent is :-
1. The combination of the compound reciprocating firebars, 6, and the pusher, 23,
worked by the same crank shaft, 16, with the coal hopper, 27, and its dividing
box, 28, together with the firebrick air inlets, 30, the parts being arranged and
operating substantially as described.
2. The firebrick air inlets, 30, placed above the firebars and projecting into the
furnace so as to become heated and to heat the air entering through them
substantially as described.
3. The improvement in steam boilers having internal furnaces, consisting in
forming in the lower parts of the outer shell and the lower parts of the internal
flues or furnace shells with one or more indentations or corrugations substantially
as and for the purposes herein before described.
In Witness whereof I, the said George Sinclair, have hereunto set my hand
and seal this second day of February in the year of our Lord One thousand
eight hundred and eighty-three.