IMPROVED CONSTRUCTION OF APPARATUS FOR OBSERVING AND RECORDING VARIATIONS OF TEMPERATURE, RANGING FROM LOW TO VERY HIGH TEMPERATURES
Year: 1877

page_text: LETTERS PATENT to Archibald Simon Lang Mac Donald, of Middlesbrough-on-
Tees, in the County of York, a Fellow of Merton College, Oxford, for the In-
vention of "IMPROVED CONSTRUCTION OF APPARATUS FOR OBSERVING AND
RECORDING VARIATIONS OF TEMPERATURE, RANGING FROM LOW TO VERY HIGH
TEMPERATURES."
Sealed the 2nd November 1877, and dated the 3rd May 1877.
PROVISIONAL SPECIFICATION left by the said Archibald Simon Lang
Mac Donald at the Office of the Commissioners of Patents on the 3rd May
1877.
ARCHIBALD SIMON LANG MAC DONALD, of Middlesbrough-on-Tees, in the County
of York, a Fellow of Merton College, Oxford. "IMPROVED CONSTRUCTION OF APPA-
RATUS FOR OBSERVING AND RECORDING VARIATIONS OF TEMPERATURE, RANGING
FROM LOW TO VERY HIGH TEMPERATURES."
The Invention relates to improved apparatus which is designed primarily to be
used for observing temperatures of high range, with special reference to its use as
applied to the blast furnace, but it is applicable to the observation of temperatures
in all circumstances, from the lowest temperature to very high ones.
The instrument consists of an air or gas thermometer and manometer or pressure
gauge so combined as to remain in permanent adjustment and indicate temperature
continuously by the observation of an index alone. It is formed of a reservoir
which may be of any size, according to the special use for which the instrument is
designed, but ranging generally from eight to twenty cubic inches in capacity; it
may be either cylindrical or bulbous, or of any other shape, and may be made of
any material, metallic or other, capable of resisting the extremes of temperature to
which it would be exposed, and impermeable by gasses, and not chemically acted upon
by the gas enclosed. If kaolin or other porcelain or fragile material be used, this is
protected from accidental mechanical injury by a metallic covering, pierced by many
and large holes; the reservoir is completely closed except at one point where there
is an opening into a tube formed either of the same material as the reservoir or of
[Price 4d.

page_text: any other that may be suitable and attached to the reservoir by suitable means, and
of a bore and length and of such dimensions and of such proportions to the magnitude
of the reservoir as may be expedient for each individual instrument. The tube may
be either straight or curved in such manner as may be convenient. This tube, or a
prolongation of it by a tube of either the same or other material, bore, or length,
communicates with some form of pressure gauge by which the pressure of gas
within the reservoir may be determined. The tube or any portion of it, straight or
curved, that is to say, for example, in the form of a worm," or otherwise, may be
immersed in a bath of water or other substance maintained at an approximately
uniform temperature, so that the gas in the pressure gauge and in portions of the
tube remoter from the reservoir than this bath may not have its temperature raised
by the heating of the gas in the reservoir.
"
If expedient, the gauge may likewise be immersed in the same or a similar bath
for the more complete effecting of this purpose, or the gauge may be constructed
with means for the rectification of errors arising from change of temperature,
according to well-known methods in common use.
The pressure gauge employed may be of such magnitude as is convenient, and
constructed on any principal applicable to the construction of an instrument for
determining the pressure of a gas, but a gauge formed in like manner to that known
as the "Bourdon gauge" is the one I prefer to use.
If desired, the instrument may be fitted with mechanism for recording the maxi-
mum and minimum temperatures, for restoring the indices of these temperatures
to the fiduciary mark, and for preventing unauthorized interference with the said
indices.
To prepare the pyrometer for use I fill it with pure dry air or other gas at a pres-
sure equal to, or greater or less than that of the atmosphere, according as sensibility
or width of range, the indications of the instrument may be desired. To graduate
it I proceed in either of two ways, but I prefer to employ both.
First. The co-efficient or co-efficients of expansion by increase of temperature of
the material or materials of which the reservoir, tube, and guage are formed, and
their respective capacities at 0° centigrade having been determined by established
methods needing no description here, and the pressure of the enclosed gas being like-
wise known, the increase of pressure of the whole of the said gas for each increment
of temperature of the gas in the reservoir, equal to one degree on any thermometric
scale, can be computed by well-known formulæ, and a scale of temperatures and
corresponding pressures constructed accordingly, and the motion of the index of the
pressure gauge for any definite charge of pressure being known the instrument can
be graduated for the indication of temperature.
Second. By observing the position of the index when the reservoir is immersed
successively in melting ice, boiling water, molten tin, lead, zinc, &c., of which the
temperatures are known, while the tube and gauge are maintained at the tempera-
ture it is intended they should have when in use, we obtain empirically a series of
pressures corresponding to certain known temperatures and the pressures corre-
sponding to other temperatures between those thus empirically determined or
beyond them can be approximately determined by calculation.
A pyrometer designed for use in observing the temperature of the blast in an
iron smelting furnace I construct generally in this way :-The reservoir in cylindrical,
formed of iron or steel, about 1 inch in external and three-fourths of an inch in
internal diameter, and from eight to thirty inches long. The tube, likewise of iron
or steel, in either fashioned in one piece with the reservoir or is welded on to it,
and the manometric apparatus is attached to the end of the tube by a perfectly air-
tight joint.
The whole instrument is filled with pure dry nitrogen gas at the
pressure of the atmosphere, and is then hermetically closed and graduated by either
or both of the methods herein-before described.

page_text: "
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Archibald Simon Lang Mac Donald in the Great Seal Patent
Office on the 3rd November 1877.
ARCHIBALD SIMON LANG MAC DONALD, a Fellow of Merton College, Oxford.
IMPROVED CONSTRUCTION OF APPARATUS FOR OBSERVING AND RECORDING VARIA-
TIONS OF TEMPERATURE, VARYING FROM LOW TO VERY HIGH TEMPERATURES."
The Invention relates to an improved apparatus which is designed primarily to
be used for observing temperatures of high range, with special reference to its use
as applied to the blast furnace, but it is applicable to the observation of temperatures
in all circumstances, from the lowest temperatures to very high ones.
The instrument consists of an air or gas thermometer and a manometer or pressure
gauge, so combined as to remain in permanent adjustment and indicate temperature
continuously by the observation of an index alone. It is formed of a reservoir
which may be of any size, according to the special use for which the instrument is
designed, but ranging generally from eight to twenty cubic inches in capacity; it
may be either cylindrical or bulbous, or of any other shape, and may be made of
any material, metallic or other, capable of resisting the extremes of temperature to
which it would be exposed and impermeable by gases, and not chemically acted
upon by the gas enclosed. If kaolin or other porcelain or fragile material be used,
this is protected from accidental mechanical injury by a metallic covering pierced
by many and large holes. The reservoir is completely closed except at one point
where there is an opening into a tube, formed either of the same material as the
reservoir or of any other that may be suitable, and attached to the reservoir by
suitable means, and of a bore and length, and of such dimensions, and of such pro-
portions to the magnitude of the reservoir as may be expedient for each individual
instrument. The tube may be either straight or curved in such manner as may be
convenient. This tube, or a prolongation of it by a tube of either the same or other
material, bore, or length, communicates with some form of pressure gauge by which
the pressure of the gas within the reservoir may be determined. The tube or any
portion of it, straight or curved, that is to say, for example, in the form of a worm
or otherwise, may be immersed in a bath of water or other substance maintained at
an approximately uniform temperature so that the gas in the pressure gauge and in
portions of the tube. remoter from the reservoir than this bath may not have its
temperature raised by the heating of the gas in the reservoir.
If expedient, the gauge may likewise be immersed in the same or in a similar
bath for the more complete effecting of this purpose, or the gauge may be constructed
with means for the rectification of errors arising from change of temperature,
according to well-known methods in common use.
The pressure gauge employed may be of such magnitude as is convenient, and
constructed on any principle applicable to the construction of an instrument for
determining the pressure of a gas, but a guage formed in like manner to that known
as the "Bourdon gauge" is the one I prefer to use.
If desired, the instrument may be fitted with mechanism for recording the maxi-
mum and minimum temperatures for restoring the indices of these temperatures to
the fiduciary mark, and for preventing unauthorized interference with the said
indices.
To prepare the pyrometer for use, I fill it with pure dry air or other gas, at
a pressure equal to, or greater or less than that of the atmosphere, according as
sensibility or width of range in the indications of the instrument may be desired.
To graduate it I proceed in either of two ways, but I prefer to employ both.
First. The co-efficient or co-efficients of expansion by increase of temperature of
the material or materials of which the reservoir, tube, and gauge are formed, and
their respective capacities at 0° centigrade having been determined by established
methods needing no description here, and the pressure of the enclosed gas being
likewise known, the increase of pressure of the whole of the said gas for each incre-

page_text: ment of temperature of the gas in the reservoir, equal to one degree on any thermo-
metric scale, can be computed by well-known formulae, and a scale of temperatures
and corresponding pressures constructed accordingly, and the motion of the index of
the pressure gauge for any definite change of pressure being known, the instrument
can be graduated for the indication of temperature.
Second. By observing the position of the index when the reservoir is immersed
successively in melting ice, boiling water, molten tin, lead, zinc, &c., of which the
temperatures are known, while the tube and gauge are maintained at the tempera-
ture it is intended they should have when in use, we obtain empirically a series of
pressures corresponding to certain known temperatures, and the pressures corre-
sponding to other temperatures between those thus empirically determined, or
beyond them, can be approximately determined by calculation.
A pyrometer designed for use in observing the temperature of the blast in an
iron smelting furnace, I construct generally in this way:-The reservoir is cylindrical,
formed of iron or steel, about one inch in external and three-fourths of an inch in
internal diameter, and from eight to thirty inches long. The tube, likewise of iron
or steel, is either fashioned in one piece with the reservoir or is welded on to it, and
the manometric apparatus is attached to the end of the tube by a perfectly air-tight
joint. The whole instrument is filled with pure dry nitrogen gas at the pressure of
the atmosphere, and is then hermetically closed and graduated by either or both of
the methods herein-before described.
Having thus described the nature of the said Invention and the manner of per-
forming the same, I say that I do not confine myself to the precise details of any
of the parts of the instrument, nor do I claim novelty in respect of the construction
of any of its several parts taken individually, but I do claim,-
First. The use of the increase of tension or pressure produced by rise of tempera-
ture in an elastic fluid or gas, for the measurement of the temperature of the blast
in iron smelting furnaces or for similar purposes.
Second. The combination in a form remaining permanently in adjustment of a
reservoir containing such gas and capable of being subjected to high temperatures,
with an instrument for indicating the increase of pressure produced in the gas con-
tained in the said reservoir by rise of temperature.
In witness whereof, I, the said Archibald Simon Lang Mac Donald, have here-
unto set my hand and seal, this Third day of November, in the year of
our Lord One thousand eight hundred and seventy-seven.
Signed and sealed by the above-
named Archibald Simon Lang
Mac Donald in the presence of
ERNEST H. BLAKER,
A. SIMON L. MAC DONALD. (L.S.)
Clerk to Messrs. Renshaw & Renshaw,
2, Suffolk Lane,
London,
Solicitors.