Improvements in Pyrometers.
Year: 1894

page_text: Date of Application, 17th May, 1894-Accepted, 5th Jan., 1895
Improvements in Pyrometers.
We, EDWARD A. UEHLING, Mechanical Engineer, and ALFRED STEINBART,
Metallurgical Engineer, both residing at 1110 North 24th Street, Birmingham, in
the County of Jefferson, and State of Alabama, United States of America, 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 :-
Our present invention involves the same principle of operation in measuring
temperature as set out in our prior Patent dated August 15, 1893 Number 15484;
and the improvement which forms the subject of this Patent consists in a method
and apparatus whereby the fluid, either by means of pressure or by vacuum, is first
passed through a minute aperture located within a medium of constaut temperature
and then through a corresponding aperture located in the medium the temperature
of which is to be measured, the change of the tension between the said apertures,
due to the difference of temperature at which the fluid passes the respective
apertures being used as a measure of the temperature to be ascertained. In
obtaining this result it is of the highest importance that the apertures shall be very
small in area and of the least ratio of the diameter to the length, in order
that the volume of the fluid passing may be to the least extent, influenced by
friction.
The accompanying drawing illustrates an apparatus for determining temperature
adapted for carrying out our present invention, the parts being shown in sectional
elevation in their relation to each other and to the chamber, the temperature of
which is to be determined.
The construction of this apparatus while being well suited for carrying out the
invention herein claimed, is only intended as one form and it is obvious that its
construction may be varied to adapt it for use anywhere and with metallurgical or
other operations in which it is important to ascertain and indicate temperature,
such as a furnace or an air blast.
330.
A represents a tube whose closed end A¹ is located at the point the temperature
of which is to be determined, the wall A showing a part of an air blast closure.
Within this tube is a smaller tube a, which extends to the inner end A' of the
outer tube, and is provided at such end with a minute aperture, a¹, which com-
municates with an air-space formed by said outer tube. The inner tube a extents
through the other end of the outer tube, and has an external branch pipe a³, while
connecting the outer tube at a point external to said air-blast chamber, is a
tube, which passes through a coupling e and is formed into a coil b, which is
placed within a vessel C for containing a liquid of constant temperature intended
to immerse the coil.
%
The coupling c is located within this vessel and the tube joins the coile
tube b within said coupling which must also be immersed in the liquid the levol
of which is indicated at z.. Within this coupling at the juncture of the pipes /"¹
and b, is placed a diaphragm provided with a minute aperture e similar to the
aperture a in the end of the pipe a, so that these two successive minute apertures
communicate with each other through the annular air-space of the tube A. The
coiled tube part is prolonged outside of the vessel by the pipe & which terminatos
in a filter D, which connects with the branch pipe d and d; while the branch
pipe a terminates in two branches e, e¹, which connect the branch pipe d, d².

page_text: A branch pipe connects with the tube f' and forms a communication with the space
within the tubes A and between the minute apertures. This branch pipe fis
the connection for properly graduated manometers for indicating temperature as
at E, F, G, H, which may be located at any desired points. The branche of the
pipe a forms the connection for the suction device B; while the branch d of the
pipe 6 forms the connection for the pressure device or air main 1. The pipes e
and are provided respectively with a stop-cock h and g, whereby the pipe i,
which forms a connection for a suitable tension regulator J and indicator jorj is
controlled.
While we have shown the two minute apertures as being in separate tubes, yet
being in direct communication with each other and with the suction or with the
pressure connections as the case may be, they are practically in one and the same
tube or chamber. That part of this tube which has the minute aperture a is inclosed
by the tube A so as to form a heat conducting space between them; the 'inclosing
tube for this purpose being made of any suitable heat conducting material
preferably platinum and located within the space, or closure, or connected with
the device the temperature of which is to be determined. The corresponding
aperture is located within the vessel which contains the coil and the medium
of normal or constant temperature whereby the fluid is maintained at a constant
temperature.
The filter preferably consists of a chamber filled with some permeable material,
such as raw cotton. At the inlet and outlet of this chamber is a perforated
diaphragm k, k which serves to give a free entrance of the fluid into and from the
chamber and prevents the filtering material being driven into the connecting pipe.
The filter-chamber is preferably made in two sections to permit of separation for
the purpose of renovating the filtering material.
Provision is also made for inspecting the tubes which are located in the medium.
the temperature of which is to be measured. For this purpose the inclosing tube A
extends ontside of the heat containing chamber and is secured in position by a
coupling K, which is preferably constructed with right and left screw threads to
make a close joint, and render the parts separable. A separate tubular coupling
section L connects the coupling K with a second coupling M which is constructed
with a knife-edge union adapted to clamp and secure the outer end of the tube a in
position concentric with the inclosing tube, and in continuous relation to the pipe a²
so that these parts are also rendered separable.
This coupling by unscrewing the part K allows the inclosing tube A to be
withdrawn for inspection; while the coupling part M permits the release and
withdrawal of the tube a for inspection. The separate tubular coupling L, while
providing a convenient construction for securing and inspecting the tube A, a,
serves also as the means of connecting the tube with the air-space surrounding
the tube a and thereby connects the two apertures.
In operating the apparatus under pressure through the pipe d to create the flow
of the measuring medium which, as shown, is by the pressure from the air-main I,
the pipe e is open to the atmosphere, the stop-cock his closed and the stop-cock
is opened, which connects the source of pressure through the pipe d with the pipe 6¹
and the aperture c¹ of the tube f¹.
!
Provision is made for regulating this pressure by connection with a pipe i which
joins the pipes d' and e¹ between the stop-cocks g and h. This provision consists of
a pressure regulator J, which contains a liquid and which maintains a constant
tension equal to the column of water it contains.
For working under pressure the pipe i is connected with a pipe which depends
within the liquid; while a short pipe in the upper end of the regulator is open
to the atmosphere above the liquid. As the pipe is immersed in the liquid
contained in the regulator, as soon as the acting pressure is equal to the column
of water m n the excess of air escapes at the bottom of the tube and bubbles up|
through the water and out the atmosphere through the tube i preventing any
This pressure is indicated by the manometer j' and in
further increase of pressure.
TH

page_text: which case the pipe i is connected by the branch-pipe o to the pipe as seen by
dotted lines o².
The air or gas under a constant pressure will now pass through the filter and the
coil bentering the aperture at a constant temperature attained in passing
through said coil which is immersed in the liquid. In its course through the
inclosing tube the air or gas assumes the temperature to be measured, and enters
at such temperature the aperture a', and flowing through the inclosed tube a,
passes out to the atmosphere through the branch pipe a' thereby causing any
changes of tension, depending on the changes in the temperature between the
apertures to be measured. These changes of tension are a measure of the
temperatures of the fluid within the tube at the point of its entrance through
the aperture a', and is indicated by a suitable graduated nanometers as at E or
at F, G, H, which are in communication with the tubes f¹ and a between the
minute apertures.
When the apparatus is operated by suction through the pipe a² to create the flow
of air or gas, the pipe d is open to the atmosphere, the stop-cock g is closed and
the stop-cock h is opened, which connects the source of suction through the pipe e
with the tube a and the aperture a', and the operation is identical with that
produced by pressure, with this difference, that, under pressure the tension at the
connections and i are above atmospheric pressure, while under suction the tension
is below atmospheric pressure at these points.
In this case the pipe i is connected with the regulator pipe i¹, the branch pipe o
is connected with the pipe and the pipes j and are left open to the atmosphere.
In consequence of this the excess of suction is supplied through the pipe
by
bubbling up through the water column m n, and the amount of suction is indicated
by the column of water rising in the pipe equal to the suction applied. In either
case the water column in the pipes or will be on a level with the level n of the
water in the regulator.
For creating the suction an aspirator B is connected with the pipe e.
It is for this purpose that we place the inlet aperture in a submerged position
within the medium of normal temperature, because it is this that gives greater
accuracy in the determination of temperature, because the measuring fluid must
thereby enter the aperture more nearly or exactly at the temperature of the medium
of normal temperature. Such position puts this inlet aperture beyond the influences
of changes. Another important matter is the provision whereby the fluid is
filtered before entering the minute aperture and thus prevents any particles of
matter lodging in or obstructing the apertures. It is also important that the part of
the apparatus which is subjected to the heat should be readily inspected and for
this purpose these parts of the apparatus are made and connected so that they can
be removed for cleaning and repair.
In practice it will be found of great advantage to be able to read the
temperature which it is desired to know at more than one point, and for this
purpose we provide a construction which will admit of indicating the temperature
at as many points as may be necessary or desirable.
While our invention is styled a pyrometer and in fact is such, yet our invention
is equally applicable to measuring temperatures of the lowest possible degree of
heat obtainable in the arts.
It will be understood that the device C may contain water at freezing or at
boiling temperature and suitable provision may be made for maintaining such
normal temperature.
:
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
1. The herein described method of determining temperature which consists in
first passing a fluid at a normal temperature and constant tension into a tube or
chamber through a minute aperture, bringing the fluid to the temperature to be

page_text: ascertained during its passage through said tube or chamber, and flowing the
fluid in this state of temperature out of the tube or chamber through a corre-
sponding minute. aperture, and utilizing the change in tension of the fluid
between the said apertures as a means to indicate the temperature to be
'determined.
2. An apparatus to determine temperature consisting of a tube or chamber
having a minute inlet aperture through which a fluid is passed under constant
tension, a reducing device to bring the fluid to a normal temperature before
entering the said inlet, a second tube having a minute aperture through which the
fluid is passed after being raised to the temperature to be ascertained, the change
in the tension of the fluid between the minute inlet and outlet apertures being used
as a means to determine the temperature to be indicated.
3. A temperature measuring apparatus consisting of a chamber or tube in which
a fluid is brought to the temperature to be determined, a tube communicating with
the said chamber near its outer end and having a minute aperture, a second tube
having a corresponding aperture connecting with the said chamber at the end
opposite that with which the first mentioned tube connects, a reducing device to
bring the fluid to a normal temperature before its passage through the inlet
aperture, the change in temperature of the fluid between the apertures being used
as a means to determine the temperature to be ascertained.
4. A pyrometer consisting of a chamber in which a fluid is raised to the
temperature to be ascertained, a tube having a minute inlet aperture and com-
municating with the outer cud of the chamber, a reducing device to bring the
fluid to a normal température before it passes through said aperture, a second
tube projected into the said heating chamber and having a minute outlet aperture
at the inner end thereof through which the fluid after being heated escapes,
the tension of the fluid between the apertures being used as a means to determine
the temperature to be indicated and the outlet aperture being located within the
reducing medium.
5. In a device for measuring temperature, the combination with a tube or
chamber having two minute apertures through one of which the measuring fluid
passes to change its tension, a reducing device to bring the fluid to a normal
temperature before its passage through the inlet aperture, a filter arranged to
intercept the flow of the measuring fluid in advance of the said reducing device,
means for forcing the fluid through said tube and its minute apertures and means
for indicating the tension of the fluid between the said apertures, substantially as
described.
6. In a device for measuring temperature, the combination with a tube having
two minute apertures through which the measuring fluid passes to change its
temperature which causes a change in its tension, a tube forming an air chamber
inclosing that part of the tube having the minute apertures located at the point
the temperature of which is to be indicated, and suitable couplings for securing
said tubes in position and for independent separation, for the purpose stated.
7. In a device for measuring temperature, the combination, with a tube or
chamber having two minute apertures through which the measuring fluid passes to
change its temperature which causes a change in its tension, a tube forming an air
chamber inclosing that part of the tube having the minute apertures, located at the
point the temperature of which is to be indicated, the branch pipe connecting the
tube and the,manometer E and the branch pipe having one or more manometers
for indicating the temperature at points distant from the apparatus.
W. P. THOMPSON & BOULT,
Agents for the Applicants.