NEW OR IMPROVED APPARATUS FOR ASCERTAINING THE TEMPERATURE OF HOT BLASTS
Year: 1875

page_text: LETTERS PATENT to Robert Main, of Glengarnock Iron Works, in
the County of Ayr, North Britain, for the Invention of "NEW
OR IMPROVED APPARATUS FOR ASCERTAINING THE TEMPERATURE OF HOT
BLASTS."
Scaled the 12th March 1875, and dated the 13th January 1875.
PROVISIONAL SPECIFICATION left by the said Robert Main at the
IONAL
Office of the Commissioners of Patents, with his Petition, on the
13th January 1875.
I, ROBERT MAIN, of Glengarnock Iron Works, in the County of
Ayr, North Britain, do hereby declare the nature of the said Invention
of "NEW OR IMPROVED APPARATUS FOR ASCERTAINING THE TEMPERATURE OF HOT
BLASTS," to be as follows, that is to say :-
::
This Invention, which relates to ascertaining the temperature of the
hot blast used in furnaces for smelting iron ore and for analogous
purposes, consists in an arrangement of apparatus wherein the tempera-
tures indicated on a mercurial thermometer or pyrometer bear a known

page_text: relation to the actual temperature of the blast itself, so that the
numerical relation being ascertained the readings of the mercurial
thermometer or pyrometer indicate the actual temperature sought to be
measured; it being here explained that the temperature of the blast is
too high to be directly measured either with a thermometer or pyrometer,
the high temperature either rendering the indications inaccurate.or
destroying the instrument when directly applied.
The apparatus constituting this Invention consists of a hollow box or
chamber, preferably double cased, the space between the casings being
filled with asbestos, or other substance of low conducting power. This
chamber is placed at any required distance from that point of the hot
blast main in which it is desired to ascertain the temperature, and is
connected thereto by a pipe which conducts the hot blast into the
chamber. The chamber is also provided with an exit through which tho
hot blast escapes. The chamber may contain a second smaller chamber
or receptacle in which the thermometer or pyrometer is placed, but this
may be dispensed with. ·
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Main in the Great Seal Patent Office on
the 10th July 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
MAIN, of Glengarnock Iron Works, in the County of Ayr, North
Britain, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of January, in the
year of our Lord One thousand eight hundred and seventy-five, in
the 38th year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Robert Main, Her special
license, that I, the said Robert Main, my executors, administrators,
and assigns, or such others as I, the said Robert Main, my executors,
administrators, or assigns, should at any time agree with, and no

page_text: "NEW OR
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
IMPROVED APPARATUS FOR ASCERTAINING THE TEMPERATURE OF HOT BLASTS,"
upon the condition (amongst others) that I, the said Robert Main,
by an instrument in writing under my hand and seal, should particu-
larly 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.
NOW KNOW YE, that I, the said Robert Main, do hereby declare.
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to
say:
My said Invention, which relates to new or improved apparatus for
ascertaining the temperature of the hot blast used in furnaces for
smelting iron ores and for analogous purposes, consists in an arrangement
of mechanism wherein the temperatures indicated on a mercurial ther-
mometer or pyrometer bear a strict relation to the actual temperature of
the blast itself, so that the numerical relation being ascertained, the
readings of the mercurial thermometer or pyrometer indicate the actual
temperature sought to be measured; it being here explained that the
temperature of the blast is too high to be directly measured either with a
thermometer or pyrometer, the high temperature either rendering the in-
dications inaccurate or destroying the instrument when directly applied.
.
And in order that my said Invention may be properly understood, I
now proceed more particularly to set forth the system, mode, or manner
in or under which the same is or may be used or practically carried
into effect, reference being had to the annexed Sheet of Drawings and
to the letters and figures marked thereon, that is to say :-
On the Sheet of Drawings hereunto appended Figure 1 is a vertical
© section of one arrangement of the new or improved apparatus con-
structed in accordance with my said Invention, whilst Figure 2 is a
transverse section of the same (drawn to an enlarged scale), and taken

page_text: on the line a, b, Figure 1. As shewn by these Figures the apparatus
consists of a hollow box or chamber A composed of inner and outer
casings c and d respectively, the space e between which is filled with
asbestos or other equivalent substance of low conducting power. The
chamber A is placed at any required distance from that point of the hot-
blast main whereat it is desired to ascertain the temperature of the
blast, and it is connected to the said main D by a pipe C, which con-
ducts the hot blast into the chamber A. The pipe C may be left
uncovered, or, as shewn at Figure 1 of the Drawings, and which is the
arrangement preferred, the pipe may be enclosed within an outer tube
or casing B throughout its entire length, or the greater portion thereof,
and the space between the said outer tube or casing B and the pipe C
may also be filled in with asbestos, or other substance of low conducting
power; or in lieu of the casing B and low conducting lining the pipe C
may simply be coated with a thickness or layer of any suitable non-
conducting material. Besides the inlet pipe C the chamber A is further
provided with an exit pipe E, through which the hot blast escapes from
the apparatus, and at the interior of the chamber A a second smaller
chamber or receptacle F is situate, as shewn, in which the thermometer
or pyrometer G is placed, the indicator end of which is extended out-
wards through one end of the apparatus. The hot blast passing through
the chamber A to the exit pipe E thereof does not come in contact with
the thermometer or pyrometer G, but acts thereon by radiation through
the chamber or receptacle F. Although this is the arrangement
preferred, it is to be understood that the chamber F may be dispensed
with, and the hot blast caused to act directly upon a thermometer or
pyrometer placed in the' chamber A. The pipe C between the hot-blast
main D and the apparatus constituting my said Invention being of a
known length and diameter the surface thereof also becomes known, and
by radiation of heat from this surface the blast becomes so reduced in
temperature that it acts upon and indicates the relative temperature on
the mercurial thermometer or on the pyrometer without injury to the
instrument employed. A scale or standard by which the relative tem-
perature of the hot blast in the main D and in the chamber A may
afterwards be calculated with sufficient accuracy, is or may be deter-
mined by placing any approved arrangement of pyrometer in the hot-
blast main D, and comparing the temperature indicated thereon with
that indicated on the thermometer or pyrometer in the chamber or
receptacle F, or when that is dispensed with in the chamber A.

page_text: The apparatus herein-before described may be permanently attached
to the hot-blast main D, and communication therewith kept open, so
that the temperature of the blast may be ascertained at any time, or the
apparatus may be made portable in order to adapt it for ascertaining
the temperature at the "plug hole," or at any other desired point in the
hot-blast main. This arrangement is illustrated in part side elevation
and part vertical section at Figure 3 of the appended Drawings, on
which L represents a tapered or conical portion formed on the lower
end of the pipe leading to the chamber A to adapt the said pipe for
entering at the “ plug hole" M, or other desired part of the hot-blast
main D.
Having now described and particularly ascertained the nature of my
said Invention, and the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, I would observe
in conclusion that what I consider to be novel and original, and therefore
claim as the Invention secured to me by the herein-before in part recited
Letters Patent is, the arrangement and construction of apparatus herein-
before described and shewn on the appended Drawings, or any mere
modification thereof, for ascertaining the temperature of the hot blast
employed in furnaces for smelting iron ores, and for other analogous
purposes.