IMPROVEMENTS IN FURNACES USED IN THE MANUFACTURE OF WELDED IRON TUBES
Year: 1865

page_text: LETTERS PATENT to Thomas Pritchard, of Wednesbury, in the County
of Stafford, Manufacturer, for the Invention of "IMPROVEMENTS IN
FURNACES USED IN THE MANUFACTURE OF WELDED IRON TUBES."
Sealed the 10th November 1865, and dated the 2nd June 1865.
PROVISIONAL SPECIFICATION left by the said Thomas Pritchard at
the Office of the Commissioners of Patents, with his Petition, on the
2nd June 1865.
I, THOMAS PRITCHARD, of Wednesbury, in the County of Stafford, Manu-
facturer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN FURNACES USED IN THE MANUFACTURE OF WELDED IRON TUBES," to be as
follows:-
In furnaces ordinarily employed in the manufacture of welded iron tubes
the strip or skelp of iron from which the tube is to be made is heated in a
chamber, through which the fire passes from the fire-place to the stack
or chimney, the draught through the furnace being produced by the stack or
chimney. In constructing furnaces used in the manufacture of welded iron
tubes according to my Invention I introduce a blast of air into the heating
chamber, the said blast entering the said chamber nearly opposite the bridge
of the furnace, but at a point considerably lower than the said bridge. The
heating chamber at the part where the blast of air is introduced is of much
greater depth than the remaining part of the said chamber into which the
strips or skelps of iron are introduced to be heated. The blast of air
described is introduced by means of a tuyere or tuyeres, and its quantity is
regulated by suitable valves or dampers. In the lower part of the heating

page_text: chamber into which the blast of air is delivered ignited coal or coke is placed,
the blast producing by its action on the fuel a gaseous combustible mixture,
which mingling with the fire from the fire-place produces a continuous sheet
or body of flame, which extends through the whole length of the heating
chamber, and heats the strips or skelps of iron to be made into tubes very
rapidly and with great uniformity, especially at the leading end of the furnace,
that is, the end from which the heated strips or skelps are drawn out.
Although I prefer introducing the blast of air at the point of the heating
chamber described, yet the said blast may be introduced at other points of the
heating chamber with nearly the same effect, provided it is introduced into
the ignited fuel in the said chamber.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Prichard in the Great Seal Patent Office on the,
30th November 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
PRITCHARD, of Wednesbury, in the County of Stafford, Manufacturer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of June, in the year of our Lord One
thousand eight hundred and sixty-five, in the twenty-eighth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Thomas Pritchard, Her special licence that I, the said Thomas Pritchard,
my executors, administrators, and assigns, or such others as I, the said
Thomas Pritchard, my executors, administrators, and assigns, should at
at any time agree with, and no others, from time to time and at all times'
thereafter during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention' for "IMPROVE-
MENTS IN FURNACES USED IN THE MANUFACTURE OF WELDED IRON TUBES," upon
the condition (amongst others) that I, the said Thomas Pritchard, my
executors or administrators, by an instrument in writing under my, or their,'
or one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the said
Letters Patent.

page_text: NOW KNOW YE, that I, the said Thomas Pritchard, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
In furnaces ordinarily employed in the manufacture of welded iron tubes
the strip or skelp of iron from which the tube is to be made is heated in a
chamber, through which the fire passes from the fire-place to the stack or
chimney, the draught through the furnace being produced by the stack or
chimney. In constructing furnaces used in-the manufacture of welded iron
tubes according to my Invention I introduce a blast of air into the heating
chamber, the said blast entering the said chamber nearly opposite the bridge
of the furnace, but at a point considerably lower than the said bridge. . The
heating chamber at the part where the blast of air is introduced is of much
greater depth than the remaining part of the said chamber into which the
strips or skelps of iron are introduced to be heated. The blast of air described
is introduced by means of a tuyere or tuyeres, and its quantity is regulated
by suitable valves or dampers. In the lower part of the heating chamber into
which the blast of air is delivered ignited coal or coke is placed, the blast pro-
ducing by its action on the fuel a gaseous combustible mixture, which mingling
with the fire from the fire-place produces a continuous sheet or body of flame,
which extends through the whole, length of the heating chamber, and heats
the strips or skelps of iron to be made into tubes very rapidly and with great
uniformity, especially at the leading end of the furnace, that is, the end from
which the heated strips or skelps are drawn out. Although I prefer intro-
ducing the blast of air at the point of the heating chamber described, yet
the said blast may be introduced at other points of the heating chamber with
nearly the same effect, provided it is introduced into the ignited fuel in the
said chamber.
Having explained the nature of my Invention, I will proceed to describe
with reference to the accompanying Drawing the manner in which the same
is to be performed.
.
Figure 1 represents in longitudinal vertical section a furnace for heating
strips or skelps of iron for the manufacture therefrom of welded iron tubes,
the said furnace containing my improvements; Figure 2 is a horizontal section
of the same, and Figure 3 is a transverse section of the same, taken through
the line a of Figure 2, the same letters of reference indicate the same parts
in each Figure of the Drawing.
b is the heating chamber of the furnace, in which the strips or skelps to
be raised to a welding heat are placed; c is the fire-place situated at one end

page_text: of the furnace, and d is the stack or chimney situated at the opposite end of
the furnace. The fire-place c communicates with the heating chamber b
through the narrow passage c³, and the end of the said chamber furthest from
the fire-place opens into the stack d. The parts described are of the ordinary
construction, and constitute no part of my Invention. At the opposite side
of the furnace to that at which the fire-place c is situated is a tuyere e, by
means of which tuyere a blast of air is introduced into the heating chamber b.
The said tuyere e does not open directly into the heating chamber 6, but into
a supplementary chamber marked of a much greater depth than the said
heating chamber b, into which the strips or skelps of iron are introduced to
be heated. The position of the tuyere e, for supplying the blast of air to the
heating chamber as well as that of the supplementary chamber 6, will be
best seen by referring to the transverse section Figure 3. The blast is
supplied to the tuyere e by means of the main pipe f, and the quantity of blast
delivered by the said tuyere is regulated by the sliding valve or damper 9.
Instead of one tuyere two or more tuyeres may be employed, but for all
ordinary purposes I have found that one tuyere is sufficient. In the lower part
of the chamber in which the blast is delivered ignited coal or coke is
placed, the said coal or coke being introduced through the opening . By
the action of the blast of air from the tuyere e upon the ignited fuel in
chamber a gaseous combustible mixture is formed, which mingling with
the fire from the fire-place c produces a continuous sheet or body of flame,
which extends through the whole length of the heating chamber b. The
strips or skelps of iron to be made into tubes placed in the said chamber are
by this means heated very rapidly and with great uniformity, especially at the
leading or fire-place end of the furnace below which the blast of air is intro-
duced, and from which end the heated strips or skelps are drawn out of the
said furnace to be welded into tubes. In addition to the tuyere e (or tuyeres)
for introducing the blast, and the chamber 63 for containing ignited fuel at the
leading or fire-place end of the furnace, as described and represented in the
Drawing, one or more tuyeres and chambers may be placed at different parts
below the level of the heating chamber b, where a very high temperature is
required, but for all ordinary purposes the arrangement of parts described and
represented answers satisfactorily.
Having now described the nature of my Invention, and the manner in
which the same is to be performed, I wish it to be understood that I do not
limit myself to the precise details herein described and represented, as the
same may be varied without departing from the nature of my Invention; but
I claim as my Invention the improvements in furnaces used in the manufac

page_text: ture of welded iron tubes herein-before described and illustrated in the accom-
panying Drawing, that is to say, introducing a blast or blasts of air into the
heating chambers of the said furnaces by preference at the leading or fire-
place end, and nearly opposite the bridge, the said blast or blasts being
delivered into ignited fuel so as thereby to produce a gaseous combustible
mixture, by means of which and the fire from the fire-place the strips or skelps
in the heating chamber are rapidly and uniformly heated.
In witness whereof, I, the said Thomas Pritchard, have hereunto set
my hand and seal, this Twenty-ninth day of November, in the year of
our Lord One thousand eight hundred and sixty-five.
Witness,
RICHARD SKERRETT,
Clerk to George Shaw,
Birmingham.
THOMAS PRITCHARD. (L.S.)