IMPROVED THERMOMETER FOR MEASURING HIGH TEMPERATURES
Year: 1884

page_text: J, JAMES MURRIE, of Glasgow, in the County of Lanark, North Britain
Engineer, do hereby declare the nature of the said invention for "A NEW On
" to be as follows:-'
IMPROVED THERMOMETER FOR MEASURING HIGH TEMPERATURES
This Invention, which relates to a new or improved thermometer for measuring
high temperatures has for its object to measure temperatures above the range of the
ordinary mercurial thermometer and is based upon the principle of causing one
fluid under pressure and rising in temperature to compress or indent another fluid
under like pressure, the said fluids being contained in closed vessels.
The instrument wherein the foregoing principle is applied under this Invention
as a temperature meter consists of a metallic vessel of the requisite thickness and
strength in which mercury is placed from this vessel a tube of small bore leads
upwards wherein the movements of the mercury corresponding to the rise and fall
of its temperature can be observed, and either upon this tube or adjacent to it a
scale is placed on which the divisions corresponding to the degrees of expansion
are marked. The upper part of this tube is provided with a vessel in which
alcohol or some analogous compressible fluid is contained and as the mercury rises,
it correspondingly compresses the alcohol, so that with a rise of temperature thero
is a corresponding rise or elevation of pressure and therefore a corresponding'
elevation of the boiling point of the mercury.
The utility of the apparatus as a temperaturo measurer is limited by the strength
of the apparatus to control the boiling point of mercury.
The mercury vessol when in use is surrounded with a casing of fireclay or other
suitable material which resists oxidation and prevents oxygen attacking the metal
of which it is composed and the alcohol vessel is also surrounded preferably by a
casing containing a fluid which keeps the alcohol vessel at a constant temperature
or nearly so.
Dated this twenty fourth day of June 1884.

page_text: •
I, JAMES MURRIE, of Glasgow, in the County of Lanark, North Britain,
Engineer do hereby declare the nature of my invention for A NEW OR IMPROVED
THERMOMETER FOR MEASURING HIGH TEMPERATURES and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:—
My Invention, which relates to a new or improved Thermometer for measuring
high temperatures, has for its object to measure temperature above the range of the
ordinary mercurial Thermometer, that is to say, temperatures ranging from zero up
to about 1500° Fahrenheit, and is based upon the principle of causing one fluid
under pressure and rising in temperature to compress or indent another fluid under
like pressure, the said fluids being contained in closed vessels.
The instrument wherein the foregoing principle is applied under this Invention
as a temperature meter, consists of a metallic vessel of the requisite thickness and
strength in which mercury is placed,-from this vessel a tube of small bore leads
upwards wherein the movements of the mercury corresponding to the rise and fall
of the temperature can be observed, and either upon this tube or adjacent to it n
scale is placed on which the divisions corresponding to the degrees of expansion
are marked. The upper part of this tube is provided with a vessel in which
alcohol or some analogous compressible fluid is contained, and as the mercury rises,
it correspondingly compresses the alcohol, so that with a rise of temperature there
is a corresponding rise or elevation of pressure, and therefore a corresponding
elevation of the boiling point of the mercury.
The utility of the apparatus as a temperature measurer is limited by the strengtli
of the apparatus to control the boiling point of mercury.
The mercury vessel, when in use, is surrounded with a casing of fireclay or other
suitable material which resists oxidation and prevents oxygen attacking the metal
of which it is composed, and the alcohol vessel is also surrounded preferably by a
casing containing a fluid which keeps the alcohol vessel at a constant temperaturo
or nearly so.
In order that my Invention may be more fully understood and readily carried
into effect, I will proceed to describe the drawings hereunto annexed.
Figure 1, is a front elevation of a form of thermometer for taking occasional
measurements of temperature and constructed according to my present Invention.
Figure 2, is a vertical section of the same.
In constructing an Instrument according to my present Invention, and as shewn
at Figures 1, and 2, the vessel a, is provided, preferably of steel, or well hammered
wrought iron of the requisite thickness and strength. This metallic vessel, may
be fully charged with mercury b, or, when great sensitiveness is required, a more
expansible fluid such as ether or water, may be placed above the said mercury as
is shewn at 8, Figure 2, under which provision the instrument is caused to work
entirely by pressure due to the tension of the vapour of such ether or water. The
vessel a, may be connected directly with the glass tube c, which is of small and
uniform bore, and wherein the movements of the mercury b, due to the variations
of temperature, can be observed, but I prefer to connect the said glass tube c, with
the vessel a, by means of the connecting tube d.-This connecting tube d, which
may be of steel or malleable iron is preferably screwed at its lower end into the

page_text: vessel a, into the mercury of which the part t, of the said tube dips, and at its
upper end it is connected to the glass tube c, by means of the nut e, collar f, and
packing 9, similar to those ordinarily employed for securing the gaugo glasses of
steam boilers within their fittings. The upper end of the glass tube c, is connected,
in manner corresponding to the lower end thereof, to the vessel h, preferably of
globular form as shewn upon the annexed Drawings. This vessel h, is provided at
its upper part with the screw cap i, or its equivalent, to admit, upon its removal,
of alcohol or some analogous compressible fluid j. being charged into the said
vessel -A scale indicating the several degrees of temperature may be marked
upon the glass tube c, but is preferably marked upon the sheath k, provided around
the said tube and formed with the elongated slot Z, through which the position of
the mercury b. may be readily observed. For rendering the instrument herein-
before described, more portable, I provide the handle m, secured to the said
instrument at any convenient part.
When in use the mercury vessel a, is surrounded with a casing of fireclay or
other refractory material as represented by the dotted lines p, upon the annexed
Drawings. This casing resists oxidation and prevents oxygen attacking the metal
of which the said vessel a, is composed.-The connecting tube d, may if found
necessary be similarly protected by a casing of fireclay or its analogue as represented
by the dotted lines 9, The vessel h, containing alcohol or other fluid is preferably
surrounded as shown in dotted lines upon the annexed drawings by a casing r, in
which is provided a fluid for maintaining the vessel h, at an approximatoly even
temperature.
The action of the instruments hereinbefore described with reference to the
annexed Drawings is as follows:-The vessel a, being subjected to heat, the
mercury b, contained therein expands, the amount of expansion being ascertained
from the position of the top thereof in the glass tube c, the mercury b, contained in
the tube d, thus acting as a connecting column. The pressure acting against the
expansive action of the mercury is comparatively slight up to a temperature of
about 600° Fahrenheit, being just sufficient to admit of the mercury b, expanding
uniformly or nearly so.-At about 600° Fahrenheit the mercury begins to expand
in a greater ratio, but this expansion can only take place along with a corresponding
compression of the fluid contained in the vessel h,-These actions may continue
until the limit is reached, the said limit being the strength of the apparatus to
control the pressure of the inercury.-It will thus be seen that the mercury, within
these instruments, is maintained in a liquid state when considerably above the
temperature at which it boils under atmospheric pressure.
In taking measurements of temperature by the Instruments constructed according
to my present Invention, the operator can, where accuracy is imperative, preserve
the vessel h, at an uniforın temperature, by filling the annular space about the said
vessel h, with water as hereiubefore described. In the event of the top of the
mercury b, in the glass tube c, not corresponding with the gauge at zero or other
favourable point for comparison, the indicator or scale can be made in the form of
a sliding bar or otherwise adjustable. This adjustable scale may be made so as to
embrace the sheath k, under which construction of instrument the scale upon the.
said sheath, may be dispensed with.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is:
First, For extending the range of mercurial or similar thermometers the
application of pressure to oppose the expansion of the mercury or other liquid
employed and thereby raise its boiling point substantially as hereinbefore set forth
with reference to the annexed Drawings.
Second. In mercurial or similar thermometers the employment of a compressible
fluid to oppose the expansion of the mercury or fluid to which the heat is applied

page_text: and thereby prevent vaporization of the latter, substantially as hereinbefore set
forth with reference to the annexed Drawings.
Third, The apparatus wherein are embodied the features or properties claimed
by the preceding claiming clauses, substantially as herein before described with
reference to the annexed Drawings.
JT100K
J. H. JOHNSON, DAY & JOHNSON,
Applicant's Agents.