An Improved Process and Apparatus for Generating Steam by the Aid of Hot or Molten Slag from Smelting or other Furnaces.
Year: 1893

page_text: Date of Application, 17th Apr., 1893
Complete Specification Left, 20th June, 1893-Accepted, 22nd July, 1893
PROVISIONAL SPECIFICATION.
'
An Improved Process and Apparatus for Generating Steam by the
Aid of Hot or Molten Slag from Smelting or other Furnaces.
We, JOHN HOWELL, Mining Manager, and EDGAR ARTHUR ASHCROFT,
Electrical Engineer, both of Broken Hill in the Colony of New South Wales do
hereby declare the nature of this invention to be as follows:-
In carrying our improved process into effect the molten slag, after tapping at the
furnace mouth, is conveyed by any suitable means to a steam generator consisting
of an outer metal shell pierced by any number of tubular receptacles having the
upper end of smaller diameter than the lower (to facilitate the removal of the slag
when cooled) the lower end being closed by a movable door. The tubular
receptacles are surrounded (wholly or partially) by water contained in the shell,
the water being thus heated and evaporated into steam. The tubular receptacles
and shell may be constructed of wrought iron, copper or any other suitable
material. As soon as the charge of slag contained in any of the tubular
receptacles has become sufficiently cooled, the door at the lower end of the tubular
receptacle is opened and the cooled mass allowed to fall out into a truck or
other receptacle for convenience of removal. The door being again closed the
tubular receptacle is then ready to receive another charge of hot slag.
In order that our invention may be clearly understood we will now describe the
same with reference to the accompanying drawings, in which the same letters refer
to corresponding parts in all the figures:
The form of apparatus which we prefer for carrying out the above process is
shown in Figures 1, 2, 3 and 4 in which,
Figure 1 is a top view of half the boiler and our special fittings.
Figure 2 is a vertical longitudinal section on line ab of Figure 1.
The left half of Figure is a vertical cross section on line c-d of Figure 1,
while the right half is an end view of the boiler. The slag pot and truck are
shown in this view only.
Figure 4 is a detail view showing the arrangement of the doors which close the
lower end of the tubular slag receptacles. In this figure one of the doors C is
shown in section at about its centre.
The shell A of the boiler is constructed of the materials usually employed in
boiler making, but the top and bottom plates of the boiler are flat, the sides and
ends being rounded as shown. Inside this shell A and extending from top to
bottom are a number of the tubular receptacles B which are intended to hold the
hot slag. These receptacles are of a greater diameter at the bottom than at the
top (as shown) which form allows the tubes to be inserted into the boiler and also
facilitates the removal of the slag when cooled. The lower end of each of the
tubular receptacles B is closed by means of a door C which is constructed
preferably of cast iron. These doors are mounted upon arms secured to weigh
bars D which extend across the bottom of the boiler, as shown more particularly
in Figure 4. The weigh bars are supported in bearings E which are fastened to
the boiler itself or to the lagging. End movement of the weigh bars is prevented
by loose collars F while each weigh bar is actuated by a handle G at one end-
the handle G being held up in place when the doors are closed by a pin H passing
through the quadrant H. Above the tubular receptacles B are a number of
funnels S each funnel extending across the boiler and feeding three tubular
receptacles. Above the funnels again are two channel irons J extending the full
length of the boiler and supported from the boiler by a series of brackets or
supports K. These channel irons. form a track for the slag-pots to be run along

page_text: Where one of the tubular receptacles B comes immediately under either of the
channel irons J a hole T is made in the channel iron to admit of a crowbar being
used to force out the cooled slag, if necessary.
Beneath the boiler we provide a truck for the reception and removal of the
cooled slag.
The boiler is provided with a steam dome L, and the usual fittings, such as
safety-valve, water and pressure gauges, &c., of the ordinary or any approved
pattern.
The boiler is surrounded with the usual heat retaining devices and lagging, but
at each end the lagging is extended some distance from the boiler and lined with
fire-brick, leaving a large bin M for the reception of broken slag. This bin M is
provided with a door N at the bottom carried by a weigh bar in a similar way to
the doors C. The boiler is supported upon a series of rails extending across the
bottom and resting upon a girder W on either side.
In this arrangement the number and the position of tubular receptacles may be
varied, as for instance, instead of having three in each cross row, it may be more
convenient to have two in each cross row, making the boiler of greater length and
smaller proportionate breadth.
Another form of apparatus by which the above process may be carried out is
shown in vertical section in Figure 5 in which the boiler shell is of circular or
square form, the top and bottom being flat. In this case the tubular receptacles B
extend from top to bottom and are closed at the bottom by the doors C. The
hinges of these doors C are secured to the boiler by the rivets which hold the
bottoms of the tubular receptacles, and the doors are held in position (when closed)
by swinging hooks or catches R. In this figure the boiler is covered by a plat-
form P preferably of cast iron provided with a separate funnel over each of the
tubular receptacles. The central enlarged tube Z is provided for the purpose of
receiving the broken slag which in Figures 1 to 4 is placed in the bins M.
Another form of the apparatus consists of a cylindrical egg ended boiler shell,
having the tubular receptacles B placed across diagonally from side to side as
shown in Figure 6, which is a vertical cross section. A platform Q runs along the
upper part of the boiler on either side for filling the tubes. Each tube is fitted
with a funnel at the upper end and a door C at the lower end. In this case it will
be necessary to provide a truck on either side to receive the cooled slag.
A convenient size for each of the tubular receptacles is from three to five feet
long, of diameter tapered from 5" at top to 10" at bottom, and they may be con-
structed of wrought iron, steel, copper or other suitable material. The arrangement
shown in Figures 1 to 4 is that which we consider the best, but it will be evident
that the size and number of the tubes and their arrangement in a boiler shell will
vary according to requirements; also, the construction and attachment of the door
at the lower end of each tube may be varied in a great number of ways and the
details as to the method of filling the tubes from the slag-pots and the means for
removing the cooled slag will be altered to suit the size and style of boiler and the
position of the boiler. The apparatus above described of whatever shape or
arrangement will require the usual boiler fittings.
.be
It is also manifest that other shaped receptacles than circular tubes may be used
for this purpose if preferred or if found more convenient. For instance, in the
apparatus illustrated in Figure 6 a tube having an elliptical cross section may.b
used with advantage for the purpose of increasing the heating surface for a given
sectional area. Tubes also of corrugated section or clongated flat section or
various other sections as shown in Figures 7, 8 and 9 may be used if desired.
The method of using this invention is as follows:-The boiler having been filled
to the required height with water, the doors C at the lower end of the tubular
receptacles B are closed and the tubular receptacles then filled with the molten
slag. The tubular receptacles being surrounded wholly or partially by the water
contained in the shell, the water is heated and evaporated into steam until the slag
has become cooled, which we have found to be in from one to two hours time, when

page_text: the doors C are opened and the cooled mass of slag allowed to fall into the truck
below, after which the doors are closed and the tubular receptacles re-filled with
hot slag. The time mentioned above for the slag to be left in the tubular
receptacles may be lengthened or shortened if preferred, and the tubular receptacles
may be filled and emptied alternately or in groups, according to the judgment of
the operator.
When applied to any particular smelting furnace the apparatus is preferably
proportioned to receive the output of slag from one or more furnaces, in which
case the operation of filling and emptying the tubes is a continuous one, for, by
the time the last tubes are filled by the slag as it is taken from the furnace the
tubes first filled have stood the required time to extract the heat and the operation
of emptying and filling is progressively repeated.
After the slag is removed from the tubes a certain quantity of heat is still
contained which could not profitably be removed by further standing, and we
prefer to utilize this heat by allowing the feed water for the boiler to pass over it
on its way to a storage tank. The operation can be readily conducted in the trucks
in which the slag is received from the tubes and bins and serves the double purpose
of heating the feed water and depositing in an insoluble form certain mineral salts
which are often present in the water and would otherwise be deposited on the tubes
in the form of scale.
After the steam has been produced in the above described apparatus it may be
conveyed in the usual way to any required place for useful work or it may be stored
in receivers, re-condensed for drinking purposes or put to any other useful
purposes.
Dated this Seventh day of March 1893.
JOHN HOWELL.
EDGAR ARTHUR ASHCROFT.
COMPLETE SPECIFICATION.
An Improved Process and Apparatus for Generating Steam by the
Aid of Hot or Molten Slag from Smelting or other Furnaces.
We, JOHN HOWELL, Mining Manager, and EDGAR ARTHUR ASHCROFT,
Electrical Engineer, both of Broken Hill in the Colony of New South Wales,
Australia, 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 is designed for the purpose of utilising hot or molten slag in the
production of steam by placing the hot or molten slag by means of suitable vessels
or receptacles within or in juxtaposition to the boiler or steam generator. It
applies to the use of slag alone or in combination with coal, wood, petroleum or
other fuel.
In carrying our improved process into effect, the molten slag, after tapping
at the furnace mouth, is conveyed by any suitable means to a steam generator
consisting preferably of an outer metal shell pierced by any number of tubular
receptacles having the upper end of smaller diameter than the lower (to facilitate
the removal of the slag when cooled) the lower end being closed by a movable
door. The tubular receptacles are surrounded (wholly or partially) by water
contained in the shell, the water being thus heated and evaporated into steam.
The tubular receptacles and shell may be constructed of wrought iron, copper or
any other suitable material. As soon as the charge of slag contained in any of
the tubular receptacles has become sufficiently cooled, the door at the lower end
of the tubular receptacle is opened and the cooled mass allowed to fall out into a
truck or other receptacle for convenience of removal. The door being again
closed, the tubular receptable is then ready to receive another charge of hot slag.
This method may be used either alone or in addition to coal, wood, petroleum or

page_text: other fuel, suitable provision being made in the shape and construction of the
boiler or steam generator.
In order that our invention may be clearly understood we will now describe the
same with reference to the two accompanying sheets of drawings and the drawings
accompanying the Provisional Specification. The same letters refer to corresponding
parts in all the figures:-
The form of apparatus which we prefer for carrying out our invention by slag
alone is shown in Figures 1, 2, 3 and 4, in which,-
Figure 1 is a top view of half the boiler and our special fittings.
Figure 2 is a vertical longitudinal section on line a-b of Figure 1. .
The left half of Figure 3 is a vertical cross section on line c-d of Figure 1,
while the right half is an end view of the boiler. The slag pot and truck are shown
in this view only.
Figure 4 is a detail view showing the arrangement of the doors which close the
lower ends of the tubular slag receptacles. In this figure one of the doors C is
shown in section at about its centre.
Figure 5 is a sectional representation of boiler shell either round or square
having flat top and bottom.
Figure 6 illustrates our tubular receptacles placed other than perpendicularly.
Figures 7, 8 and 9 show different shapes of tubular receptacles.
Figure 10 shows the arrangement we prefer when combining the slag with a coal
or other fuel furnace, and
Figure 11 shows a modification of the arrangement in Figure 10.
The shell A of the boiler (referring to Figures 1 to 4) is constructed of the
materials usually employed in boiler making, but the top and bottom plates of the
boiler are flat, the sides and ends being rounded as shown. Inside this shell A
and extending from top to bottom are a number of the tubular receptacles B which
are intended to hold the hot slag. These receptacles are of a greater diameter at
the bottom than at the top (as shown) which form allows the tubes to be inserted
into the boiler and also facilitates the removal of the slag when cooled. The lower
end of each of the tubular receptacles B is closed by means of a door C which is
constructed preferably of cast iron. These doors are mounted upon arins secured
to weigh bars D which extend across the bottom of the boiler, as shown more
particularly in Figure 4. The weigh bars are supported in bearings E which are
fastened to the boiler itself or to the lagging. End movement of the weigh bars is
prevented by loose collars F, while each weigh bar is actuated by a handle G at
one end--the handle G being held up in place when the doors are closed by a pin H
passing through the quadrant H¹. Above the tubular receptacles B are a number
of funnels S, each funnel extending across the boiler and feeding three tubular
receptacles. Above the funnels again are two channel irons J extending the full
length of the boiler and supported from the boiler by a series of brackets or
supports K. These channel irons form a track for the slag-pots to be run along.
Where one of the tubular receptacles B comes immediately under either of the
channel irons J, a hole T is made in the channel iron to admit of a crowbar being
used to force out the cooled slag, if necessary.
Beneath the boiler we provide a truck or trucks for the reception and removal
of the cooled slag.
The boiler
provided with a steam-dome L and the usual fittings, such as
safety-valve, water and pressure-gauges, &c., of the ordinary or any approved
pattern.
The boiler is surrounded with the usual heat retaining devices and lagging, but
at each end the lagging is extended some distance from the boiler and lined with
fire-brick, leaving a large bin M for the reception of broken slag. This bin M is
provided with a door N at the bottom carried by a weigh bar in a similar way to
the doors C. The boiler is supported upon a series of rails extending across the
bottom and resting upon a girder W on either side.
In this arrangement the number and the position of tubular receptacles may be

page_text: varied, as for instance, instead of having three in each cross row, it may be more
convenient to have two in each cross row, making the boiler of greater length and
smaller proportionate breadth.
Another form of apparatus by which our invention may be carried out is shown
in vertical section in Figure 5 in which the boiler shell is of circular or square
form, the top and bottom being flat. In this case the tubular receptacles B extend
from top to bottom and are closed at the bottom by the doors C. The hinges 0 of
these doors C are secured to the boiler by the rivets which hold the bottoms of
the tubular receptacles, and the doors are held in position (when closed) by swinging
hooks or catches R. In this figure the boiler is covered by a platform preferably
of cast iron provided with a separate funnel over each of the tubular receptacles.
The central enlarged tube Z is provided for the purpose of receiving the broken
slag which, in Figures 1 to 4, is placed in the bins M.
Another form of our apparatus consists of a cylindrical eggended boiler shell,
having the tubular receptacles B placed across diagonally from side to side as
shown in Figure 6, which is a vertical cross section. A platform Qruns along the
upper part of the boiler on either side for filling the tubes. Each tube is fitted.
with a funnel at the upper end and a door C at the lower end. In this case it will
be necessary to provide a truck on either side to receive the cooled slag.
Another form of the apparatus is illustrated in Figure 10 in which the tubular
slag receptacles are combined with a furnace for coal, wood or other fuel. In the
arrangement shown in Figure 10 we prefer to sink the boiler into the ground
leaving the funnels at the mouth of the tubular receptacles just level with the
surface. We construct the shell A. of the boiler in the form of a Cornish boiler
and provide it with a furnace flue P placed centrally in which may be burned coal,
wood or other suitable fuel. On each side of this furnace flue a number of our
tubular slag receptacles B are secured in a perpendicular position, each of the
receptacles being provided with a funnel S at its upper end and a door C at the
lower end. There may be a separate funnel at the upper end of each receptacle or
one funnel may be made to feed several receptacles. The door C at the lower end.
of each tube is hinged to the boiler shell and is provided with a lever handle C¹
whereby it can be operated. At the back of the door is a bracket C² provided!
with holes into which a pin C³ can be fitted to hold the door either when closed or
open. Below the tubular receptacles, and beneath either side of the boiler is a line
of rails for carrying the trucks which receive the cooled slag. The tunnels or
chambers in which these trucks run will require to be large enough to allow ample.
room for working the doors C and, if desired, they may be closed by a door at
either end to retain the heat. The position and shape of the return flues will be
varied to suit the position, shape and arrangement of the tunnels or chambers.
In Figure 11 we have shown a modification of the construction shown in
Figure 10. The shell of the boiler is constructed in the same form as that in.
Figures 1, 2 and 3, but it is provided with two longitudinal tubes P and P¹, the
lower one P is the furnace flue and the upper P¹ is a return flue.
In this arrangement the doors C are held by swinging catches and worked by
means of a hooked rod or handle, suitable eyes being provided on the doors and
catches.
In the case of petroleum being employed instead of the coal or wood the usual
apparatus for supplying the petroleum would take the place of the coal or wood
furnace.
In these two figures the funnels being on a level with the surface of the ground,.
the receptacles may be filled from the usual slag-pots mounted on wheels or if the
boiler is near enough to the furnace the slag may be run direct into the funnels by
means of a shute.
A convenient size for each of the tubular receptacles is from three to five feet
long, of diameter tapered from four to six inches at top to ten or twelve inches at
bottom, and they may be constructed of wrought iron, steel, copper or other
suitable material. The arrangement shown in Figures 1 to 4 for the tubular

page_text: receptacles alone or in Figure 10 for the tubular receptacles combined with the
usual furnace, are those which we consider the best, but it will be evident that the
size and number of the tubes and their arrangement in a boiler shell, whether used
alone or in conjunction with the usual furnace tube will vary according to require-
ments; also, the construction and attachment of the door at the lower end of each
tube may be varied in a great number of ways, and the details as to the method of
filling the tubes from the slag-pots and the means for removing the cooled slag will
be altered to suit the size and style and the position of the boiler. The apparatus
above described of whatever shape or arrangement will require the usual or
approved boiler fittings.
be
It is also manifest that other shaped receptacles than circular tubes may be used
for our purpose if preferred or if found more convenient. For instance in the
apparatus illustrated in Figure 6 a tube having an elliptical cross section may
used with advantage for the purpose of increasing the heating surface for a given
sectional area. Tubes also of corrugated section or elongated flat section or various
other sections, as shown in Figures 7, 8 and 9, may be used if desired.
The method of using this invention is as follows:-The boiler having been filled
to the required height with water, the doors C at the lower end of the tubular
receptacles B are closed and the tubular receptacles then filled with the molten
slag. The tubular receptacles being surrounded wholly or partially by the water
contained in the shell, the water is heated and evaporated into steam until the slag
has become cooled, which we have found to be in from one to two hours time, when
the doors are opened successively and the cooled masses of slag allowed to fall
into the truck below, after which the doors are closed and the tubular receptacles
re-filled with hot slag. The time mentioned above for the slag to be left in the
tubular receptacles may be lengthened or shortened, if preferred, and the tubular
receptacles may be filled and emptied alternately or in groups, according to the
judgment of the operator.
When applied to any particular smelting furnace the apparatus is preferably
proportioned to receive the output of slag from one or more furnaces, in which case
the operation of filling and emptying the tubes is a continuous one, for, by the time
the last tubes are filled by the slag as it is taken from the furnaces the tubes first
filled have stood the required time to extract the heat and the operation of
emptying and filling is progressively repeated.
After the slag is removed from the tubes a certain quantity of heat is still
contained which could not profitably be removed by further standing, and we prefer
to utilize this heat by allowing the feed water for the boiler to pass over it on its
way to a storage tank. The operation can be readily conducted in the trucks in
which the slag is received from the tubes and bins and serves the double purpose of
heating the feed water and depositing in an insoluble form certain mineral salts,
which are often present in the water and would otherwise be deposited on the tubes
in the form of scale.
After the steam has been produced in the above described apparatus it may be
conveyed in the usual way to any required place for useful work or it may be stored
in receivers, re-condensed for drinking purposes, or put to any other useful
purposes.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The production of steam by means of hot or molten slag contained in any
number of tubular receptacles so constructed as to admit of a ready removal of the
cooled masses of slag-the tubular receptacles being secured in an outer shell and
surrounded (wholly or partially) by the water it is intended to evaporate.
2. The combined application of hot or molten slag with coal, wood, petroleum or
other fuel as means of generating steam.
3. In apparatus for the production of steam by means of hot or molten slag, the

page_text: use of tapered tubular receptacles of greater sectional area at the lower end than
at the upper end and of circular, elliptical, corrugated or other suitable section
surrounded by the water to be evaporated and provided with suitable doors at the
lower end.
4. In apparatus for the production of steam by means of hot or molten slag in
tubular receptacles, the disposal of the tubular receptacles vertically between the
ends or sides of the generator shell, and the general arrangement of parts, substan-
tially as described and as illustrated in Figures 1, 2, 3 and 4.
5. In apparatus for the production of steam by means of hot or molten slag in
tubular receptacles, the disposal of the tubular receptacles, crossed alternately from
the opposite sides of a cylindrical shell and closed by doors at the lower end,
substantially as described and as illustrated in Figure 6.
6. In apparatus for the production of steam, the combination with any form of
coal or other fuel furnace of tubular receptacles preferably such as those described
and illustrated herein, by which molten slag is utilized as an heating agent for the
production of steam, substantially as described and illustrated in Figures 10
and 11.
Dated this Fourth day of May 1802
JOHN HOWELL.
EDGAR ARTHUR ASHCROFT.