IMPROVEMENTS IN APPARATUS FOR INDICATING TEMPERATURE AND PRESSURE
Year: 1885

page_text: JAMES MURRIE, 206 Gallowgate Street Glasgow, Lanarkshire, North Britain
Engineer, do hereby declare the nature of my invention for IMPROVEMENTS IN
APPARATUS FOR INDICATING TEMPERATURE AND PRESSURE, to be as follows:-
My said Invention has for its object to improve the construction of apparatus for
indicating temperature or pressure and more especially apparatus of the kind
described in my Patent Specifications N° 9393 and 15947 of 1884, and 303 of
1885.
In apparatus of the kind referred to where the liquid in the expansion chamber
is permitted to volatilize at. a pressure less than the atmospheric pressure, in
addition to the employment of a column of mercury working in an analogous
manner to a barometer, with the surface of the liquid wholly or partially relieved
of the atmospheric pressure, a mouth piece with pet cock may be fitted to the
opposite end of the apparatus, to permit the interior of the Instrument to be
wholly or partially relieved of the atmospheric pressure, or the connection at the
end adjacent to the Indicator may be permanently or temporarily fitted with some
exhausting apparatus of any known design.
The apparatus described in the aforesaid patents may have fitted to them in any
convenient part any known form of pressure gauge combined with a safety valve or
other pressure relieving apparatus, which is in communication with any known
form of alarm or apparatus for giving indications of such excess of pressure. The
pressure relieving apparatus may consist of a spring under compression with valves
as commonly adopted on steam generators or any other known form of safety
valve. The aforesaid valve being in communication with a bell pull or other
audible indicator placed at any desired point. When the aforesaid apparatus is
applied to taking indications of comparatively high temperatures, the expansion
chamber and parts exposed to the action of the heat may be covered with asbestos
or other material which permits conduction to take place slowly and uniformly, and
Prine &

page_text: the opposite end of the apparatus may have fitted to it any known form of chrono-
meter or time indicator to enable the time to be measured during which the
mercury is being heated in the body of the non-conducting material. Such time
re-corder may have a scale attached to it shewing the corresponding temperature.
When the aforesaid apparatus for indicating temperatures is constructed of
glass, a vacuum may be produced at either end of the Instrument by the common
method of expanding the liquid and sealing the terminal or extremity of the tube,
or if a partial vacuum be sufficient by constructing the leg or legs of the instru-
ment to give the desired degree of actual pressure compared with the atmospheric
pressure.

page_text: JAMES MURRIE, 9. Shuttle Street, Glasgow, Lanarkshire, North Britain, Engineer,
do hereby declare the nature of my invention for IMPROVEMENTS IN APPARATUS
FOR INDICATING TEMPERATURE OR PRESSURE, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
My said invention has for its object to improve the construction of apparatus for
indicating temperature or pressure and more especially apparatus of the kind
described in my patent specifications N° 9393 and 15947 of 1884 and 30385.
:
In apparatus of the kind referred to where the liquid in the expansion chamber,
is permitted to volatilize at a pressure less than the atmospheric pressure, in
addition to the employment of mercury working in an analogous manner to a
barometer with the surface of the liquid wholly or partially relieved of the atmos-
pheric pressure, a mouth piece with pet cock may be fitted to the opposite end of
the apparatus, to permit the interior of the instrument to be wholly or partially
relieved of the atmospheric pressure, or, the connection at the end adjacent to
the indicator may be permanently or temporarily fitted with some exhausting.
apparatus of any known design. The apparatus described in the aforesaid patents.
may have fitted to them in any convenient part any known form of pressure gauge
combined with a safety valve or other pressure relieving apparatus, which is in
communication with any known form of alarm or apparatus for giving indica-
tions of such excess of pressure. The pressure relieving apparatus may consist
of a spring under compression with valves as commonly adopted on steam
generators: or, any other known form of safety valve. The aforesaid valve being
in communication with a bell pull or other audible indicator placed at any
desired point.
When the aforesaid apparatus is applied to taking indications of comparatively.
high temperatures, the expansion chamber and parts exposed to the action of the
heat may be covered with asbestos or other material, which permits conduction to:
take place slowly and uniformly, and the opposite end of the apparatus may have.
fitted to it any known form of chronometer or time indicator to enable the time to
be measured during which the mercury is being heated in the body of the non-
conducting material. Such time recorder may have a scale attached to it, shewing.
the corresponding temperature.
When the aforesaid apparatus for indicating temperatures is constructed of glass,
a vacuum may be produced at either end of the instrument by the common
method of expanding the liquid and sealing the terminal or extremity of the.
tube, or, if a partial vacuum be sufficient by constructing the leg or legs of the
instrument to give the desired degree of actual pressure as compared with
the atmospheric pressure.
In order that the aforesaid modifications of the apparatus for indicating tempe->
rature, or pressure be more clearly understood, I will describe more minutely the
construction and arrangement of these modifications,

page_text: Fig. 1 mustrates the most simple mode of obtaining a vacuum in the space over
the mercury or other liquid in the expansion chamber. A. B. represents the column
or leg corresponding to the mercurial barometer. C the pet cock, plug, cap or other
contrivance for exhausting the confined fluids to a greater or less extent. D repre-
sents the indicator. The leg A. B. being partially filled with mercury and made of
sufficient length to exceed the barometric column, a vacuum is easily formed in the
upper end by first charging the tube with mercury when in an inverted or inclined
position, and permitting the surplus liquid escaping by the opening at "C" on the
leg A B. being raised to the vertical position.
Fig. 2. represents a modified form of the aforesaid instrument. The straight
part of the tube A. B. contains the mercury: C, D, represents a number of coils
which are partially filled with mercury at the end adjacent to the straight stem.
E, the cap pet cock or plug referred to: F. the indicator. The action of this form
of instrument is essentially as follows. The extremity of the straight tube being
elevated sufficiently above the horizontal causes the mercury to flow towards the
lower end, leaving a vacuum ats extremity, the coils being partially filled with,
water prevents the mercury passing onwards towards the indicator, but which
liquid at the same time transmits the pressure from the mercury to the indicator,
while the cap can be unscrewed to permit part of the confined fluid to escape to
ensure a complete vacuum being formed at the higher end of the instrument.
Fig. 3, represents one mode of combining a pressure relieving apparatus with or
without an alarm arrangement, to any of the aforesaid instruments for indicating
temperature or pressure. A. represents the expansion chamber, B, the connecting
tube, C, the safety valve, diaphragm, or other contrivance: D, an alarm in the
form of a steam whistle. E represents the gauge. The action is essentially as
follows, the expansion chamber on being subjected to the action of heat, the vapour
contained therein volatilizes, the pressure of the vapour being transmitted thro' the
intervening confined fluid or fluids to the indicator. When it is an object to
permit the liquid in the expansion chamber to escape into the intermediate part of
the hollow tube without permitting any of the confined fluids to escape outside the
apparatus, a diaphragm or other analogous contrivance which changes its position
on being subjected to pressure is employed, the diaphragm is weighted or balanced
in such a manner that on a predetermined pressure or temperature being exceeded
the elastic part of the diaphragm expands, and in the act of expanding may or
may not operate or actuate mechanism which sets an alarm in action. Should the
alarm consist of an ordinary steam whistle, the mechanism opens a pet cock or
valve which regulates the flow of the steam from a vapour generator to the
whistle, or the mechanism may set any known form of alarm in motion, such as an
alarm bell or other contrivance.
When it is an object to permit part or whole of the confined fluids escaping
outside of the apparatus proper, an ordinary safety valve, piston plunger or similar
contrivance may be set in motion on a predetermined pressure being exceeded.
Said apparatus being likewise in communication with an alarm arrangement of a
corresponding kind to that already described.
Fig. 4 represents one modification of these instruments for indicating temperature
or pressure with the straight part of the tube A. B. enveloped in a body of a
comparatively. high-melting point. On the straight part of the instrument being
subjected to the action of the heat, the heat takes some time to pass thro' the casing
or casings, the comparative time taken to heat the mercury between two pre-
determined points being noted, and the corresponding temperature ascertained from
data determined by experiment.
Fig. 5 represents one modification of the instrument constructed of glass, the
vacuum on either end of the confined liquid being obtained by the same mode as
that adopted in constructing mercurial thermometers. "A.B." represents the bulb.
"C," the graduated stem.-
Fig. 6. represents another modification of instrument, which may be constructed
partially of glass or wholly of metals, A, B. represents the expansion chamber

page_text: "C" the dip pipe more particularly described in my complete specification
No 9393. "D," the indicator. E, the cap, in this case, placed at the lower end of
the expansion chamber, and which may either be utilized in creating a vacuum
in the expansion chamber, or for charging the chamber with a fluid or fluids.
The apparatus herein before described may be charged with any desired liquid
or liquids depending on the temperature it is desired to indicate, the action of the
apparatus is precisely the same or nearly the same as those described in my
aforesaid complete specifications, more particularly N° 30385.
When any of the apparatus herein before described is employed to indicate
pressures other than those generated by heat, as for instance in indicating the
pressure in a town's water supply pipe, said apparatus is fitted at any desired
point with a branch connecting pipe, with or without a valve or corresponding
contrivance, which enables the branch passage being closed at pleasure: the branch
piece referred to is connected to the water pipe or other vessel or chamber
containing the fluid under pressure, and on the confined fluids being brought in
direct communication with each other, and the indicator on the aforesaid apparatus
being graduated to indicate temperature or pressure, it follows that the pressure
existing in the hydraulic press, town's water pipe or other vessel containing a fluid
under pressure will be shewn on the aforesaid indicator. The apparatus can in
this manner be made to indicate pressures other than those generated by heat.
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,-
1. The design and construction of instrument for indicating temperature or
pressure illustrated in Fig. 1. and the mode of obtaining a vacuum at the extremity
of the straight stem therein, substantially as hereinbefore described.
2. The pet cock, cap or plug, on any of the aforesaid apparatus for indicating
temperature or pressure as a means of creating a vacuum therein, or for charging
the chambers of the apparatus with a fluid or fluids.
3. The combination of the aforesaid apparatus, more particularly as shewn in
Fig. 3, with a safety valve, diaphragm, or other known form of pressure relieving
valve, substantially as hereinbefore described.
4. The application of the aforesaid pressure relieving apparatus to actuate or set
in motion any known form of audible indicator, on the pressure or temperature of
the confined fluids exceeding a predetermined point.
5. The encasing the expansion chamber of the aforesaid apparatus for indicating
temperature or pressure in a jacket of clay or other material and the mode
of estimating temperature substantially as shewn in Fig. 4 and hereinbefore
described.
6. The design of instrument for indicating temperature or pressure shewn on
Fig. 6. and the mode of creating a complete or partial vacuum therein.
JAMES MURRIE