Year: 1895

page_text: Date of Application, 22 NOV., 1895
Complete Specification Left, 24th Aug. 1896-Accepted, 26th Sept., 1896
I, EDGAR ARTHUR ASHCROFT, of Willyama Works, Grays, in the County of
Essex, Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to an improved method of, and apparatus for, applying the
heat of slag or other hot material coming from a smelting or other furnace, to the
purpose of generating steam.
The improved method consists, first, in supplying the heated slag or material to
the heating chamber of the boiler in such manner that the material will be spread
out in a thin layer so as by the continuous or intermittent accretion of material to
present a constantly or frequently renewed heat radiating surface of extended area.
By this method of supplying the material in a succession of superposed thin
layers the heat of each layer is radiated and utilized as the layer is deposited on
the already cooled subjacent layers, so that the superjacent layer is always the
hottest, the method being distinguishable in this respect from the cooling down-
wards from the surface of a mass of considerable depth of which the internal
portions, owing to the poor heat conducting quality of the material, will retain their
heat long after the surface portion has become cooled. The method consists,
secondly, in assisting the convection of the heat from the exposed surface of the
hot material, to the heating surface of the boiler by means of a current of air
passing over the surface of the hot material, then over the heating surface of the
boiler, and then over a freshly renewed surface of the hot material, and so on in a
continuous cycle.
The boiler comprises an outer shell and internal heating chamber which
resembles the fire-box of an ordinary vertical boiler, except that it has no fire-
grate and is closed at bottom by the hearth, this chamber being circular in plan
and of slightly conical form. The steam dome is of lesser diameter than the main
body which is traversed by a number of vertical flues leading from the heating
chamber to the space around the steam done. A central tube, provided with a
funnel, leads through the steam dome to the heating chamber, through which the
hot material is supplied to the hearth and air is conveyed to the heating chamber
to quickly convey the heat of the material to the heating surface of the boiler.
The tube and funnel may be sealed against the escape of air or closed by a stopper
in the intervals of supply. The boiler is enclosed in an annular flue space within
a brickwork setting, this flue space being closed at top and bottom and divided by
a horizontal plate at about the level of the top of the boiler shell, the flue above
this division plate being referred to as the upper flue and the space below it as the
lower or outer flue. The latter has a vertical partition at one side of which the
top and bottom flues communicate by an aperture in the horizontal division whilst
at the other side a pipe connects the lower part of the outer flue to the casing of
a fan of which the delivery pipe is connected to the central tube whereby a
continuous circulation of heated air through the boiler is produced. The boiler
may be supported by brackets on pairs of longitudinal and cross girders, the
latter resting on the former and bridging over a tunnel beneath. The hearth is
adapted to close the bottom of the heating chamber and is constructed of non-
conducting material, such as fire-brick, held in a metal tray of circular form

page_text: carried by a trolly on which the material, when cooled, can be conveyed away.
The tray has an external flange adapted to abut against the bottom of the boiler
shell when the hearth is raised to its operative position, so as to close the heating
chamber, the raising and lowering of the hearth being performed by means of an
hydraulic ram carrying a section of the track upon which the trolly runs.
axles of the trolly wheels are coupled together by side bars, and the body of the
trolly is adapted to pivot about one of the axles when its other end is lifted off
the other axle, for discharging the cooled material from the hearth.
The
The operation is as follows:-The hearth being in its raised position, the slag
or other hot material from the furnaces is poured through the central tube and
becomes spread out on the hearth in a thin layer which radiates heat and is
continuously or intermittently renewed, the slight central super-elevation of the
material exposing a greater area and disposing it to greater advantage. To assist
the transference of the heat to the boiler, a continuous circulation of air is
maintained by the fan, the air being delivered through the central tube becoming
heated in passing over the material on the hearth, then passing up through the
vertical flues into the upper flue, through the aperture into the outer flue, and
around the body of the boiler to the tube by which it is returned to the fan after
having been thus brought into contact with a very extended heating surface which
may, of course, be further increased in a variety of well known ways. When the
heating chamber is nearly filled the hearth is lowered by means
of the ram,
wheeled away on its trolly and the heated exhausted material discharged, the
hearth being then returned and raised into position again, or another one being
brought into use in its place.
The generation of steam will depend jointly on the rate at which bot material
is supplied and at which the air is circulated, and it will be seen that by a
rapid circulation of air, as above described, the rate of generation may be very
rapid.
Dated this 22nd day of November 1095
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.
apparatus for Generating Steam.
I, EDGAR ARTHUR ASHCROFT formerly of Willyama Works, Grays in the
County of Essex, England, and at present of Newcommen Street, Newcastle, in
the Colony of New South Wales, Australia, Electrical Engineer, 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 an improved method of, and apparatus for, applying
the heat of slag or other hot material coming from smelting or other furnaces, to
the purposes of generating steam.
The improved method consists, first, in supplying the heated slag or material to
the heating chamber of the boiler in such manner that the material will be spread
out in a thin layer so as by the continuous or intermittent accretion of material to
present a constantly or frequently renewed heat radiating surface of extended
area. By this method of supplying the material in a succession of superposed
thin layers, the heat of each layer is radiated and utilized as the layer is deposited
on the already cooled subjacent layers so that the superjacent layer is always the
hottest, the method being distinguishable in this respect from the cooling down-
wards from the surface of a mass of considerable depth of which the internal

page_text: portions, owing to the poor heat conducting quality of the material, will retain
their heat long after the surface portion has become cooled.
The method consists, secondly, in assisting the convection of the heat from the
exposed surface of the hot material to the heating surface of the boiler by means
of a current of air passing over the surface of the hot material, then over the
heating surface of the boiler, and then over a freshly renewed surface of the hot
material, and so on in a continuous cycle.
The improved apparatus for carrying this method into effect is illustrated in the
accompanying drawings forming part of this specification wherein
Figure 1 is a side elevation of the boiler, the setting being in section and the
hearth in the lowered position. Figure 2 is a vertical section of the same, the
hearth being in the raised or operative position.
Figure 3 is a plan of the boiler, the setting being in section mainly on line a b,
Figure and partly (that is to say between the lines e f aud 9 h) in section on
line cd, Figure 1.
Figure 4 is a plan of the hearth partly broken away to shew its supporting
trolley.
The same letters of reference denote like parts in all the figures.
Referring to Figures 1 to 4 the boiler comprises the outer shell A A' and
internal heating chamber B which resembles the fire-box of an ordinary vertical
boiler except that it has no fire-grate and is closed at bottom by the hearth, this
chamber being of circular form in plan and of slightly conical form. The steain
dome A is provided with a steam outlet pipe A2 and is made of lesser diameter
than the main body A which is traversed by a number of vertical flues C leading
from the heating chamber B to the space around the steam dome A¹. A central
tube D leads through the steamn dome to the heating chamber through which the
hot material is supplied to the hearth and air is conveyed to the heating
chamber B to quickly convey the heat of the material to the heating surface of
the boiler, the material being dumped or otherwise supplied through the tube D
and funnel E which may be sealed against the escape of air or closed by a
stopper E in the intervals of supply.
The
The boiler is enclosed in an annular flue space within a brickwork setting, this
flue space being closed at top and bottom and divided by a horizontal plate Lat
about the level of the top of the body A the fluc above this division plate being
referred to as the upper flue and the space below it as the lower or outer flue.
The latter has a vertical partition M, Figure 3, at one side of which the top and
bottom flues communicate by an aperture P in the horizontal division L whilst at
the other side a pipe H connects the lower part of the outer flue to the casing of
a fan N' of which the delivery pipe N is connected to the central tube D whereby
a continuous circulation of heated air through the boiler is produced.
boiler may be supported by brackets on pairs of longitudinal and cross girders, the
latter resting on the former and bridging over a tunnel beneath. The hearth is
adapted to close the bottom of the heating chamber and is constructed of non-
conducting material such as fire-brick, held in a metal tray F of circular form
carried by a trolly, on which the material when cooled can be conveyed away.
The tray has an external flange adapted to abut against the bottom of the boiler
shell A when the bearth is raised to its operative position, so as to close the
heating chamber B, the raising and lowering of the hearth being performed by
means of an hydraulic am K carrying a section of the track upon which the
trolly runs. The axles of the trolly wheels are coupled together by side bars and
the body of the trolly is adapted to pivot about one of the axles when its other
end is lifted off the other axle, for discharging the cooled material from the
heartli.
The operation is as follows:-The hearth being in its raised position the slag
or other hot material from the furnace is poured through the central tube D and
becomes spread out on the hearth in a thin layer which radiates heat and is
continuously or intermittently renewed, the slight central super-elevation of the

page_text: To
material exposing a greater area and disposing it to greater advantage.
assist the transference of the heat to the boiler a continuous circulation of air is
maintained by the fan N¹ the air being delivered through the pipe N and central
tube D becoming heated in passing over the material on the hearth, then passing
up through the flues C into the upper flue, through the aperture P into the outer
flue, and around the body A of the boiler to the tube H by which it is returned
to the fan after having been thus brought into contact with a very extended
heating surface. When the heating chamber is nearly filled, the hearth is lowered
by means of the ram K, wheeled away on its trolly, and the heated exhausted
material discharged, the hearth being then returned and raised into position again,
or another being brought into use in its place.
The generation of steam will depend jointly on the rate at which hot material
is supplied and at which the air is circulated, and it will be seen that by a
rapid circulation of air as above described the rate of generation may be very
rapid.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
:―
1. The herein described method of heating a steam boiler by molten slag or
other hot material coming from a blast or other furnace, the said method consisting
essentially in spreading the slag in thin superimposed layers on a hearth within
the heating chamber of the boiler, and at same time cansing a current of air to
circulate over the freshly deposited layer of hot material, then in contact with the
heating surfaces of the boiler, then back over the hot material, and so on in a
continuous cycle as specified.
2. A steam boiler adapted to be leated by hot or molten material having an
internal heating chamber closed at bottom by a removable hearth, a central supply
pipe and flues leading up from the heating chamber through the water space of the
boiler to a flue space above, as specified.
3. A steam boiler adapted to be heated by hot or molten material having an
internal heating chamber closed at bottom by a removable hearth, a central supply
pipe, flues leading up from the heating chamber through the water space of the
boiler to a flue space above the said flue being separated from, but communicating
with, a lower or outer flue around the boiler shell divided by a vertical partition
and communicating with an exhaust pipe as specified.
4. The combination, with a boiler having an internal heating chamber closed by
a removable hearth, a central supply pipe, and flues leading up from the heating
chamber through the water space of the boiler to flues above and around the
boiler shell, of a fan and air circulation pipes respectively connected with the
central supply pipe and the said outer flue whereby a continuous circulation of air
is maintained in a cycle over the freshly deposited layers of hot material and in
contact with the heating surfaces of the boiler as specified.
5. In a boiler as described the combination, with an internal heating chamber, of
a hearth of non-conducting material to receive the hot material, adapted to fit in
and completely close the lower end of the heating chamber and of means,
substantially as specified, for raising and lowering the same and of conveying the
cooled material away.
Dated this 22nd day of August 1896.
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.