Improvements in or relating to the Process of Melting Iron.
Year: 1897

page_text: Date of Application, 27th Jan., 1897
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Process of Melting Iron.
We, THOMAS DOHERTY, of Wellington Street, Sarnia, in the County of Lambton,
and Province of Ontario, Canada, Manufacturer, and PETER DUNCAN CRERAR of
No. 1 Provident Chambers, Hughson Street South, in the City of Hamilton,
County of Wentworth, Ontario, aforesaid, Barrister-at-Law, do hereby declare the
nature of this invention to be as follows:
This inveation has for its object improvements relating to the melting of iron.
In British Letters Patent No. 8368 of 1896 the use of steam is described in the
process of melting iron the amount of such steam being regulated so as to pro-
duce a blue or hydrogen flame which can be seen at the charge hole of the cupola.
Now according to our present invention the amount of steam introduced and
the time for introducing same is ascertained and regulated in the following
manner and by adopting the following process:
The cupola (which may be of any sunable character) is prepared and the charge
placed therein in the well-known manner at present in use in Great Britain or
in any other desired and suitable manner as for instance a low cupola or low
charge hole may be used and charged and operated as in the United States of
America.
The air blast is turned on and a certain amount of steam arises from the water
used in the sand bottom of the cupola and this steam acts on the first iron melted
in the manner we desire but the source of such steam is soon exhausted and this
is indicated we have found by the metal as it flows out of the furnace giving
of quit and large sparks in place of very fine and brilliant sparks which are to
be observed while the proper amount of steam is present in the furnace and
acting on the metal.
We now introduce steam (advantageously high pressure or dry steam) from
any suitable source into the bottom or lower part of the cupola (advantageously
through the tuyere) for instance said steam may be injected with the air blast
in the manner and by the means such as described and illustrated in the aforesaid
Patent No. 8368 of 1896 or in any other suitable or desired manner.
A space or opening or observation hole is left or provided (advantageously a
circular hole) around the steam and air pipes or injector through which observa-
tion hole or holes according to this invention certain indications can be observed
and thereby the supply of steam regulated.
These indications are as follows:-
The proper amount of steam to produce the desired results in or upon the iron
in process of melting is determined by regulating same until a particular halo
or multi-coloured flame or aureola is seen (through the aforesaid observation
hole) apparently around the outlet end of the injector or concentric therewith.
This flame or aureola appears with a blue or hydrogen tint towards the centre
and a yellow or yellowish tint around or towards the outer edge or fringe where-
upon same indicates that the proper amount of steam is being introduced'; that

page_text: is to say, we have found that the best results are obtained in the metal by regu-
lating the amount of steam so that such flame or halo is steadily maintained
during the process of melting.
If too little steam is being introduced the said indication does not appear and
also if too much steam is being introduced; and in the latter event, such steam
can be seen with the eye through the aforesaid observation hole; or in other words,
when insufficient steam or an excess thereof is being introduced to produce the
best results on the metal the aforesaid flame or aureola does not appear and its
absence indicates the necessity for regulating the steam.
Besides the indication thus afforded by the aforesaid halo or aureola-a further
indication is afforded by the sparks from the outflowing metal which are and con-
tinue to be small and brilliant when the proper proportion of steam is being
introduced while when the proper amount of steam to produce the best results is
not being introduced then no sparks appear or, if any, then they are large and
less brilliant i.e. no sparks appear when there is excess of steam and if sparks
appear large and dull this indicates insufficient steam.
Improvements in or relating to the Process of Melting iron.
We, THOMAS DOHERTY, of Wellington Street, Sarnia, in the County of Lambton,
and Province of Ontario, Canada, Manufacturer, and PETER DUNCAN CRERAR, of
No. 1 Provident Chambers, Hughson Street South, in the City of Hamilton,
County of Wentworth, Ontario, aforesaid, Barrister-at-Law, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained im and by the following statement: —
This invention has for its object improvements in or relating to the melting of
iron.
In British Letters Patent No. 8368 of 1896 the use of steam is described in the
process of melting iron the amount of steam used being regulated so as to produce
a blue or hydrogen flame which can be seen at the charge hole of the cupola.
Now according to our present invention the amount of steam introduced into
the furnace or cupola and the time for introducing same is ascertained and regu-
lated and maintained in the following manner and by adopting the following
process:-
*
1.1.1
The cupola or furnace (which may be of any suitable character) is prepared and
the charge placed therein in the well-known manner at present in use in Great
Britain or in any other desired and suitable manner as for instance a low cupola
(or low charge hole) may be used and charged and operated as in the United
States of America.
•
The air blast is turned on and a certain amount of steam arises from the water
used in the sand bottom of the cupola and this steam may act on the first iron
melted in the manner we desire but the source of such steam is soon exhausted
and this is indicated we have found by the metal as it flows out of the furnace
giving off dull and large sparks in place of very fine and brilliant sparks which
are to be observed while the proper amount of steam is present in the furnace
and acting on the metal.

page_text: We now introduce steam (advantageously high pressure or dry steam) from any
suitable source into the bottom or lower part of the cupola said steam being
injected with the air blast through the tuyeres.
A space or opening or observation hole is left or provided (advantageously at
each tuyere) through which observation hole or holes certain indications can be
observed and thereby the supply of steam regulated according to this invention.
These indications are as follows:-
The amount of steam to be used in the process of melting iron is determined
according to this invention by regulating such steam until a particular halo or
multi-coloured flame or aureola is seen (through the aforesaid observation hole
or holes) apparently around the outlet end of each injector or concentric therewith.
This flame or aureola appears with a blue or hydrogen tint towards the centre
and a yellow or yellowish or reddish yellow tint around or towards the outer edge
or fringe thereof whereupon same indicates that the proper amount of steam is
being introduced that is to say we have found that the best results are obtained
in the metal by regulating the amount of steam so that such flame or halo is
steadily maintained during the process of melting. When insufficient steam or
an excess thereof is being introduced to produce the best results on the metal the
aforesaid flame or aureola does not appear and its absence indicates the necessity
for regulating the steam.
Besides the indication thus afforded by the aforesaid halo or aureola-a further
indication is afforded by the sparks from the outflowing metal which are and
continue to be small and brilliant when the proper proportion of steam is being
introduced while when the proper amount of steam to produce the best results
is not being introduced then no sparks appear or if any then they are large and
less brilliant i.e. no sparks appear when there is excess of steam and if sparks
appear large and dull this indicates insufficient steam.
The results which we obtain cannot be obtained by a haphazard injection of
steam; on the contrary if steam is injected in insufficient amount no appreciable
benefit is derived and if in excessive amount it will be a positive and serious detri-
ment. It is not practicable to regulate the steam supply by any formula having
relation to the measurements of the cupola or other fixed data-as the quantity
required to produce the results obtained by our process may vary from day to
day as for instance with the humidity of the atmosphere the quality of the iron
and fuel in the cupola and probably also with other matters such as the column
and velocity of the air blast and the boiler pressure. We have however dis-
covered that when the steam is being injected in the proportions which will pro-
duce the beneficial results herein before referred to there are certain coincident
phenomena sufficiently marked to be a guide to any man of ordinary intelligence
skilled in the trade or art of metal founding and by a due attention to these indi-
cative phenomena the proper supply of steam can be regulated and the beneficial
results of our process secured.
The guide or indications according to our present invention are available with
any usual form of cupola.
We will now describe our present invention with reference to the annexed
drawings which illustrate a cupola with combined air blast and steam blast.
A indicates the cupola.
BB indicates the tuyeres.
C is the main air-blast pipe and c the branch pipes which convey the air blast
to the tuyeres B; and D is the main steam pipe and d d are branch pipes there-
from leading into the tuyeres and with open ends in the tuyeres forming injec-
tors e e.
* are steam valves.
y are observation holes.
For a cupola not exceeding 3 feet 6 inches diameter it will be found that
a main steam pipe of 1 inch diameter will be sufficiently large
to convey the steam from the boiler and that branch pipes of inch diameter

page_text: will be large enough to convey the steam from the main pipe into the tuyeres. A
larger cupola would probably require the pipes proportionately larger.
The steam pipes d'are provided with suitable regulating cocks or valves and
also a valve or valves (not shown) may be provided in the air-blast pipe or pipes
the air blast being produced by any suitable means and the steam being sup-
plied from any suitable source and if the source of steam is at any considerable
distance from the cupola or if from other cause the steam has a tendency to con-
dense in the pipes it may be dried or superheated by passing it through a heated
coil or other suitable heating apparatus near the cupola or it may be superheated
if desired above the tuyeres inside the lining of the cupola by conducting it
through a pipe run round inside such lining.
The following is given as an illustration of carrying out our invention:-
After placing the charge of coal or coke in the cupola the fire is started and
allowed to burn until the gases burn through, the iron and fuel are then charged
into the cupola in the usual way. The air blast is turned on as im ordinary
practice and in a few minutes the iron begins to run.
In ordinary foundry practice the bottom of the cupola is lined before each melt
with sand which latter contains a considerable quantity of water.
As the tempera-
ture inside the cupola rises this water is vapourized and usually volumes of steam
When this
can be seen escaping from the cupola at the tuyeres and other vents.
steam is exhausted which is generally in from 10 to 15 minutes after the air
blast is turned on the injection of steam into the cupola should be commenced
beginning with a small supply at each tuyere and gradually increasing the supply
by opening the valves in each pipe until the liquid metal flowing from the tap
hole of the cupola ceases to throw off the large reddish sparks which are an
ordinary feature of outflowing molten metal from a cupola and instead the flow-
ing metal produces numerous small and brilliant sparks which shoot out to the
height of apparently about an inch or two above the surface of the metal.
These characteristic sparks or flashes of light are a constant reliable indication
that the steam is being injected in the proper quantities and the disappearance
of these sparks will be an indication that the steam is not being supplied in the
requisite quantity and that the desired chemical actions in the cupola are not
being obtained.
If the molten metal is throwing off large coarse reddish sparks the supply of
steam is insufficient and should he increased; if there are no sparks being thrown
off that indicates that the steam is being injected too freely and the supply should
be gradually diminished at each tuyere until the small brilliant flashes or sparks
reappear.
་
In addition to this guide from the appearance of the outflowing metal we have
discovered another phenomenon which can be observed and should be maintained
throughout the melt according to our present invention-and this can be relied
on either independently of or in conjunction with the rule just given. When
the steam is turned on (moderately at first and gradually increasing) and regulated
the operator on looking in at the observation hole or holes y of any of the tuyeres
may when the supply of steam becomes sufficient observe a circular flame or
aureola apparently round or immediately in front of the orifice or outlet of the
steam pipe i.e. at about the point marked z in the drawings.
This aureola is of a bluish colour in the centre and has a fringe of yellow or
reddish-yellow light around it not unlike the blue centre and yellow fringe of
the flame from an ordinary gas jet. We have found that when this aureola
appears it serves as an indication that the supply of steam is in the desired amount.
If there is no aureola visible and if the steam cannot be seen as a vapour stream-
ing from the orifice of the pipe into the cupola there is not enough sicam being
injected and the supply should be slowly increased at each tuyere until the aureola
appears at each steam pipe. If there is no aureola apparent and the steam (appa-
rently undecomposed and in the form of steam) can be seen streaming from the

page_text: injectors into the cupola the steam is being injected in excessive quantities and
the supply should he gradually diminished until the aureola appears.
When once the proper supply is arrived at by observing either or both of the
foregoing directions it is seldom necessary during the melt to again adjust the
valves but it is prudent from time to time to take note of one or other of these
indications in case any change inside the cupola should require an adjustment of
the steam supply.
The steam is injected continuously until the melt is over and turned off when
the wind blast is turned off.
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. In producing a cast iron of the nature set forth (by charging a cupola with
fuel and metal raising the heat of the contents by the aid of an air blast to a
degree sufficient to liquefy the metal and injecting steam in conjunction with the
air-blast into the cupola) the regulation of the supply of steam by keeping it at
such a rate of flow that the molten metal running from the tap hole of the cupola
produces small and brilliant sparks shooting but a short distance (apparently an
inch or thereabouts) from the surface of the molten metal until a circular
aureola bluish at the centre and yellow or reddish-yellow towards the fringe or
circumference- can be observed around or immediately in front of and nearly or
quite concentric with the orifice of the steam injector substantially as and for
the purposes herein before described.
or
and
2. The herein-described improvements in or relating to the process of melting
iron which consist in injecting steam into the cupola in such manner and in such
quantity until the phenomena or indications hereinbefore described can be
observed by the operator and regulating the said steam supply by means of such
indications or phenomena so as to steadily maintain the latter while the melting
process continues substantially as and for the purposes set forth.
3. In the use of steam in the process of melting iron determining and regulating
the quantity of steam injected into the cupola in the manner and for the purposes
substantially as herein before described.
Dated
זג
L
100%
TONGUE & BIRKBECK,
Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicants.