AN IMPROVED PYROMETER
Year: 1885

page_text: I, JOHN FREW, of Langloan Iron Works, near Coatbridge, Lanarkshire, Iron
Works Manager, do hereby declare the nature of my Invention for "AN IMPROVED
PYROMETER," to be as follows:-
The object of my Invention is to provide an improved pyrometer or device for
continuously indicating temperatures. In applying the improved pyrometer to
indicate the temperature of the hot blast, the varying degree of expansion of a
volume of air, due to variations in the temperature of the hot blast, is employed
to move a liquid column or other indicator over a graduated scale, in order to
indicate the temperature of the hot blast.
'
In a convenient arrangement of the improved pyrometer which I have
experimentally found to serve the purpose in view, a blast of air at approximately
uniform temperature and constant pressure is led by a tube through a small orifice
in a tubular worm or other hollow vessel placed within the hot blast pipe, such
worm or vessel exposing a considerable surface to the hot air. An outlet orifice
is provided for the escape from the worm or hollow vessel of the air, but such
outlet is made of smaller size than the inlet, in order that an uniform pressure
slightly higher than the atmospheric pressure may be maintained therein. The
worm communicates by means of a tube with a vessel containing a coloured liquid,
and provided with a vertical glass tube in which the liquid rises. The expansion
of the air within the worm, due to the heat communicated thereto by the hot
blast, induces a pressure in the worm or other hollow vessel, which causes the
coloured liquid to be forced up the glass tube to an extent which will vary
according to the expansion of the air within the worm, and therefore according to
the temperature of the hot blast. The coloured liquid may be a mixture not
readily vapourised by heat, or in lieu of a liquid any other well known means of
indicating pressure, such for example as a spring and pointer may be employed.
A graduated scale is provided to indicate the extent of movement of the indicator,
so that correct readings may be taken at any time of the temperature of the blast.
A uniform pressure of the cold blast passing to the worm may be obtained by
the use of a pressure reducing valve, or in a simple manner by dipping a branch
from the cold blast inlet pipe into water kept at a uniform level.

page_text: ан порто
I, JOHN FREW of Langloan Iron Works near Coatbridge, Lanarkshire, Iron
Works Manager, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :—
The object of my invention is to provide an improved pyrometer or device for
continuously indicating temperatures. In applying the improved pyrometer to
indicate the temperature of the bot blast or for similar use the varying degree
of expansion of a volume of air or other aëriform fluid due to variations in the
temperature of the hot blast is employed to move a liquid column or other indicator
over a graduated scale which serves to indicate the temperature of the hot blast.
The accompanying diagram illustrates a convenient arrangement of the improved
pyrometer and connections which I have found to serve the purpose in view. A
blast of air at approximately uniform temperature and constant pressure is led by
a tube J, through a small orifice or nozzle K, into a tubular worm L, or other
hollow vessel placed within the hot blast pipe such worm or vessel exposing a
considerable surface to the hot air. An outlet orifice M is provided for the escape
from the worm or hollow vessel of the air, but such outlet is made of larger size
than the inlet in order that a uniform pressure only slightly higher than the
atmospheric pressure may be maintained therein. The worm L, or tube J,
communicates by means of a tube N, with a vessel O, containing a coloured liquid
and provided with a vertical glass tube P in which the liquid rises.
The expansion of the air within the worm L, due to the heat communicated
thereto by the hot blast induces a pressure in the worm or other hollow vessel
which causes the coloured liquid to be forced up the glass tube P, to an extent
which will vary according to the expansion of the air within the worm L, and
therefore according to the temperature of the hot blast. The coloured liquid may
be a mixture not readily vapourised by heat or in lieu of a liquid any other well
known means of indicating pressure such for example as a spring and pointer may
be employed. A graduated scale is provided to indicate the extent of movement
of the indicator so that correct readings may be taken at any time of the
temperature of the blast. The scale is constructed by experimentally ascertaining
the positions of the indicator at known temperatures. A uniform pressure of the
cold blast passing to the worm may be obtained by the use of a pressure reducing
valve or in a simple manner by dipping a branch from the cold blast inlet pipe
into water kept at a uniform level. In the arrangement illustrated the device
employed for securing uniform pressure consists of a water cistern C, provided
with a central open tube F in which dips a pipe B. The cistern is filled by the
pipe D, and a uniform level is maintained the gauge G, serving to indicate the
level. The cold blast is admitted by the tube A, to the larger pipe B, and thence
it passes by the pipe H, to the pipe J, in which is the small regulating nozzle K.
The movement of the indicating liquid up and down the tube P, is effected by
variations of pressure of the air passing through the pipe J, such variation being
due to the expansion of the air in the tube L, and to its consequent retardation in
passing out through the nozzle M.

page_text: 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 herein described pyrometer or device for indicating temperature
consisting of a spiral tube or other vessel supplied with air at a uniform pressure
said tube being fitted within the hot blast pipe or chamber whose temperature is
to be ascertained and being connected to a vessel containing a coloured liquid and
provided with a glass tube and graduated scale or other indicator substantially as
set forth.
(2.) The combination of the spiral tube L, air pipe J, nozzles K, M, pipe N,
liquid vessel O, glass tube and scale P, with devices substantially as described for
supplying air at approximately uniform pressure to the tube L.
CRUIKSBANK & FAIRWEATHER,
135, Buchanan Street, Glasgow,
Agents.