Improvements in and connected with Steam Boilers and Furnaces therefor.
Year: 1899

page_text: Date of Application, 28th Feb.,
1899
Complete Specification Left 28th Nov 1890 Accented 6th Jan
1000
PROVISIONAL SPECIFICATION.
Improvements in and connected with Steam Boilers and Furnaces
therefor.
I, ALEXANDER GRANGER, of Briar Bank, Eastend, Broxburn, in the County of
Linlithgow, Scotland, Oil Refiner, do hereby declare the nature of my invention
to be as follows:-
My invention relates to improvements in and connected with steam boilers
and furnaces therefor whereby certain advantages are obtained. In order to
render the description of my invention clearer, I have appended a sheet of draw-
ings, in which Figure 1 is a longitudinal section, while Figures 2, 3, and 4, are
cross sections of a Cornish boiler to which my invention is applied. Figures 5
and 6 are details of the fire-bars. I desire it however to be clearly understood
that although the drawings and descriptions which I hereafter give are with
reference to my invention as applied to a Cornish boiler, the invention can with
equal readiness be applied to other forms.
For the purposes of this specification I may divide my invention into two
parts: (a) the mechanical stoker, (b) the force draught arrangement.
As regards (a) the mechanical stoker, it will be noted in Figure 1 that I
employ an ordinary hopper a in conjunction with two breaking rollers bbl which
are to be used when the coal employed is in large blocks. Immediately below
the breaking rollers are the fire-bars c, which project beyond the front of the
boiler, so that the coal which passes between the breaking rollers falls directly
thereon. By means of the roller-cams ce a motion of translation backwards
and forwards is given to the bars, the cams being so disposed that the bars are
brought forward severally but are all thrust back collectively, whereby the coal
is caused to move from front to back of the boiler.
The fire-bars c do not, as in the usual form of Cornish boiler, terminate at a
point short of the fire bridge. In my invention no fire-bridge need be employed,
the bars passing right through the length of the boiler and out at the back.
From Figures 5 and 6 it will be seen that the fire-bars I employ are not of the
usual well known types. They have at either end a solid portion dd, between
which is a perforated part C. The section of bar may be described as a
T section, but it will be noticed that the head of the T is not a straight line but
is formed of two lines making an obtuse angle with one another. The fire-
bars are carried upon suitable rollers ee.
Affixed to the back of the boiler is the ash-pit A, into which the ends & of
the fire-bars project. The ash-pit is provided with two closely-fitting doors f
and f. The door f is so arranged that when it is opened the accumulated ashes
can-be removed. The door f' on the other hand, which is in close proximity to
the ends of the fire-bars is the orifice by which the furnace fire is lighted.
This, it will be noticed, is done from the back of the boiler and not from the
front. That part of the main flue not already hermetically closed by the
ash-pit is sealed by means of the plate g. At this point it may also be remarked
that the front end of the main flue is also closed by means of the plate h, in
which are the doors i, and k, which are employed for cleaning out coals or
ashes

page_text: With respect to (b) or the force draught part of my invention it will be seen
from the drawings that I employ a second flue B, opening immediately out of the
fire-flue at the front end of the boiler. More than one such flue could be used
if desired. This flue B passes through the length of the boiler, and out at the
back into the brick chimney D which chimney is split into two branches E E¹.
These branches in turn lead to the two lower flues f f which pass along the
length of the boiler and unite at the front end in the single brick return flue G.
It might be found desirable to unite the second flue or flues B with the lower
flues EE by means of cross internal flues inside the boiler altogether. The
return flue & passes backward under the boiler to the heating chamber H in
which are the force draught coils I the upper ends of which are open to the air.
Into these upper ends are inserted the nozzles of the steam-pipes the steam for
which is preferably obtained from the upper part of the boiler.
The action of my invention is as follows. The fire is lit in the usual way,
from the door f¹ in the ash-pit. Steam is then injected into the coils I in the
heating chamber H. These coils pass ultimately through the sealing-plate at the
back of the boiler and come out below the fire-bars. It will thus be seen that
steam and heated air which pass through the coils will be forced through the
perforated fire-bars, thereby producing a more or less complete combustion of
the green coal. Not only is a force draught thus obtained but it will be noticed
that the hot gases which pass through the heating chamber are employed to
heat the air drawn into the coils I by means of the steam jets 7 so utilizing the
heat of the waste gases.
The flame from the coal along with the hot gases now traverse the various flues
in the direction indicated by the arrows, the products of combustion eventually
escaping by the chimney as shown.
I desire it to be clearly understood that although I have described a-specific
form of my invention as applied to a Cornish boiler, I can equally well employ
my invention with reference to other boilers and with modifications both as
regards the mechanical stoker and force draught parts of my invention without
in any way departing from the spirit thereof.
י
DEE
T
1000
COMPLETE SPECIFICATION.
Improvements in and connected with Steam Boilers and Furnaces
therefor.
I, ALEXANDER GRANGER, of Briar Bank, Eastend, Broxburn, in the County of
Linlithgow, Scotland, Oil Refiner, do hereby declare the nature of my invention
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement: —
My invention relates to improvements in and connected with steam boilers
and furnaces therefor whereby certain advantages are obtained. In the drawings
left with the Provisional Specification Figure 1 is a longitudinal section, while
Figures 2, 3, 4, are cross sections of a Cornish boiler to which my invention is
applied. Figures 5 and 6 are details of the fire-bars. I desire it however to
be understood that although the drawings and descriptions which I hereafter
give are with reference to my invention as applied to a Cornish boiler, the inven-
tion can be applied to other forms.

page_text: For the purposes of this description I may divide my invention into two
parts: (a) the mechanical stoker, (b) the forced draught arrangement.
As regards (a) the mechanical stoker, it will be noted in Figure 1 that I
employ an ordinary hopper a formed of sheet iron or the like, in which the fuel
is placed. The lower orifice of the hopper is directly above the breaking
rollers 66 which are to be used when the coal employed is in large blocks. The
breaking rollers consist essentially of two cylindrical drums on the periphery of
which are projecting teeth or spikes meshing with each other.
Immediately below the breaking rollers are the fire bars c which in my inven-
tion project beyond the front of the boiler, so that the coal which passes between
the breaking rollers falls directly thereon. Roller cams c 2 are placed below the
fire bars and these engage with projections thereon, the cams and projections
being so arranged that the bars are brought forward severally but are all thrust
back collectively, whereby the coal is caused to move from front to back of the
boiler.
The breaking rollers are closed in by means of the metal covering h the lower
edge of which is made to overlap the ends of the fire-bars. This metal cover-
ing his moreover carried below the fire-bars so as to enclose also the roller cams
and is affixed to a plate covering the entrance to the main flue.
Doors and are formed in these metal coverings to permit access to the
interior for cleaning out coals and ashes or for effecting repairs or the like.
The fire-barse do not, as in the usual form of Cornish boiler, terminate at a
point short of the fire bridge. In my invention no fire bridge need be employed
the bars passing right, through the length of the boiler and out at the back.
From Figures 5 and 6 it will be seen that the fire-bars I employ are not of the
usual well known types. They have at either end a solid portion dd¹ between
which is a perforated part C. The form of bar that I prefer to employ is
approximately of T section, but it will be noticed that the head of the T is not
a straight line but is formed of two lines making an obtuse angle with one
another. The fire-bars are carried upon suitable rollers ee which are supported
from the walls of the main flue.
Affixed to the back of the boiler is the ash-pit A. The ash-pit A is so
arranged that the ends of the fire-bars project into it so that the ashes are
finally tipped therein by the to-and-fro motion of the fire-bars. The ash-pit is
provided with two closely fitting doors f and f¹. The door f is formed in the
lower part of the ash-pit so that when it is opened the accumulated ashes can be
removed either by shovelling out or by dropping them direct into a wheel barow.
The door f on the other hand is formed in the upper part of the ash-pit in close
proximity to the ends of the fire bars to enable the furnace fire to be lighted
from it. This it will be noticed is done from the back of the boiler and not from
the front. That part of the main flue not already hermetically closed by the
ash-pit is sealed by means of plate g.
With respect to (b) or the forced draught part of my invention it will be seen
from the drawings that I employ a second flue B, opening immediately out of the
fire flue at or near the front end of the boiler. More than one such flue could be
used if desired. This flue B passes through the length of the boiler, and out at
the back into the chimney D, which can be formed of brick, iron or other suit-
able material. The chimney D is split into two, branches E E¹ these branches
in turn lead to the lower flues of the number of which is again immaterial,
which pass along the length of the boiler and unite at the front end in the single
brick return flue G. Here again however a plurality of return flues could be
employed. It might be found desirable to unite the second flue or flues B with
the lower flues EE by means of cross internal flues inside the boiler altogether.
At the back of the boiler for preference is the heating chambers H of brick or
other suitable material and into this the return flue G passes backward under the
boiler. This heating chamber H contains the force draught coils I consisting of
bent piping the upper ends of which pass outward through the wall of the heating

page_text: chamber and are open to the air. Into the upper ends of these pipes or at some
intermediate point are inserted the nozzles of the steam pipes 7 the steam for
which is preferably obtained from the upper part of the boiler. The steam for
injection can if desired be raised in a separate steam producer.
The force draught coils traverse the heating chamber and pass finally through
the sealing plate g into the fire flue.
The action of my invention is as follows. The fire is lit in the usual way,
from the door f¹ in the ash-pit. Steam is then injected into the coils I in the
heating chamber H and as these coils pass ultimately.through the sealing plate
at the back of the boiler and come out below the fire bars it will be seen that
steam and heated air pass through the coils and are forced through the per-
forated fire-bars, thereby producing a more or less complete combustion of green
coal. Not only is a forced draught thus obtained but it will be noticed that the
hot gases which pass through the heating chamber are employed to heat the air
drawn into the coils I by means of the steam jets e so utilizing the heat of the
waste gases.
The flame from the coal along with the hot gases now traverse the various flues
in the direction indicated by the arrows the products of combustion eventually
escaping by the chimney as shown.
I desire it to be understood that although I have described my invention as
applied to a Cornish boiler, I can employ it in connection with other boilers.
Having now particularly described and ascertained the nature of my invention
and in what manner the same is to be performed, I declare that what. I claim
is:-
(1) The employment of a forced draught the direction-of-which is through and
over fire-bars and fuel from back to front substantially as described and illus-
trated.
'
(2) The employment of a fire-flue or fire-flues traversing the entire length of the
boiler in which are movable fire-bars projecting at front and back in con-
junction with a forced draught mechanism substantially as described and illus
trated.
(3) The arrangement and combination of hoppers, breaking rollers, cams and
fire-bars in conjunction with a forced draught mechanism substantially as set
forth.
(4) The arrangement and combination of flues to enable the products of com-
bustion to escape from the fire flue at or near the front of the boiler, substan
tially as set forth.
(5) In conjunction with a boiler and stoking mechanism as set forth the
arrangement and combination of a heating chamber, forced draught coils and
injection steam pipes all as described and illustrated.
(6) Fire-bars of approximate T section the extremities of which are solid while
the rest is perforated in conjunction with a boiler and forced draught mechanism
substantially as set forth.
(7) In conjunction with a boiler and forced draught mechanism as set forth
the employment of an ash-pit with two doors substantially as described and
illustrated.