Apparatus for Measuring or Indicating Temperatures at a Distance.
Year: 1898

page_text: Date of Application, 28th July, 1898-Accepted, 3rd Sept., 1898
COMPLETE SPECIFICATION.
Apparatus for Measuring or Indicating Temperatures at a Distance.
I, ARTHUR JALlan de la CroIX, of Wassilieffsky Ostroff 6th Line No. 61, St.
Petersburg, Russia, 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 :-
This invention relates to a new construction of atmospheric thermometer or
apparatus for indicating temperatures at a distance, which possesses the following
peculiar features.
The apparatus, which I term a "Telethermometer" is mainly intended for
observing the temperature of grain in stores or produce in silos, for the purpose of
preventing the spontaneous heating thereof; but it is also applicable for other
purposes such as for observing the temperature in flour mills, drying chambers,
factories, and generally in all localities where materials or goods are stored that are
liable to spontaneous heating, or where it is desired to control the temperatures of
several separate localities from a central observing station.
The apparatus consists of a hermetically closed glass vessel which is placed either
in the space containing the material whose temperature is to be observed, or it is
imbedded in the said material. This vessel is connected by a thin lead tube with a
second, considerably smaller, vessel, also hermetically closed and partly filled with
mercury.
The cover of this second vessel is of glass, of a dome shape, through which passes
a glass stand-pipe formed in one therewith and whose upper end opens into the
atmosphere, while the lower end is immersed in the mercury. When in use, the
above named vessels are filled with air under a certain moderate pressure above that
of the atmosphere, causing the mercury to rise in the stand-pipe to a corresponding
extent.
The action of the apparatus is as follows: When a change takes place in the tem-
perature of the space or of the materials in which the larger vessel of the apparatus
is placed, the air pressure in the two vessels increases or decreases to a corresponding
extent, causing a corresponding rise or fall of the mercury in the stand-pipe of the
smaller vessel.
The capacity of the latter, as also of the tube connecting the vessels, is, even with
a considerable length of the tube, very small compared with that of the large vessel.
In consequence hereof the inaccuracy due to the fact that the whole of the air con-
tained in the apparatus is not subject to the same temperature, is exceedingly small,
and therefore of no practical importance, so that the height of the column of mer-
cury in the stand-pipe will indicate with sufficient practical accuracy, upon a scale,
the temperature of the space or material in which the large vessel is contained.
This scale is marked on a strip of stiff paper or the like, which may conveniently be
placed in the space between the stand-pipe and an outer glass tube fitted over the
same, and preferably united with the stand-pipe at top so as to prevent dust &c. from
entering the annular space.
The small vessel with the stand-pipe can, if necessary be situated at some distance
from the larger vessel. In cases where the temperatures of several separate spaces

page_text: are to be observed, the smaller vessels of the several apparatus may be arranged in
one or more groups or rows at a central locality.
In most practical applications of the apparatus, such as that above mentioned for
preventing the spontaneous heating of grain in stores or other substance in silos, it
is not so much a question of ascertaining accurately the temperature of the materials
as of indicating any rise of temperature thereof, such for instance as may be
caused by the commencement of any spontaneous heating thereof. In such cases,
and generally in all cases where it is not desired to indicate the temperature with
accuracy, the indications of the above described apparatus are sufficient in them-
selves; but where accuracy is required it is necessary to effect a correction according
to the condition of the barometer for the time being.
It is an essential feature of the apparatus that all connections of the apparatus are
formed as hydraulic joints so that all escape of air therefrom is prevented.
This arrangement enables the apparatus to be constructed of different kinds of
materials such as are best suited for the particular purpose to which the several parts
of the apparatus are to be applied, as before stated, the vessels are generally made of
glass and the connecting tube of lead.
The apparatus thus constructed alone enables the principle of the atmospheric
thermometer to be applied for indicating temperatures at greater or less distances
(for which the ordinary construction of atmospheric thermometers is quite unsuitable)
and to be maintained for years thoroughly reliable and without deterioration.
The apparatus is shewn on the accompanying drawings, in which Figure 1 shews a
view of the large vessel partly in section, Figure 5 a vertical section of the small
vessel, and Figures 2, 3, 4 and 6 enlarged details of the latter.
The large glass or porcelain vessel A, Figure 1, has approximately the shape of an
inverted bottle, that is, having the neck downwards. Through the neck is passed a
thin metal tube with open upper end, while the lower end is hermetically united
with the before mentioned lead tube f leading to the smaller vessel.
The connection of the said tube to the vessel A is effected by means of a flange a
soldered to the tube, between which flange and the mouth of the bottle is inserted a
caoutchouc or other packing disc b.
The flange is pressed against the mouth of the bottle by means of a metal cap c
formed with a screw thread, screwing on a thread formed on the neck of the vessel.
Before connecting the tube f with the vessel A, a certain quantity of glycerine or
other uncongealable neutral liquid, is introduced into the latter, so that, after
inverting the vessel as described, such liquid will collect in the neck so as to cover
the connection with the tube f, and thus form a perfect hermetic hydraulic
joint.
The quantity of glycerine is so regulated that the upper open end of the tube f
rises well above its surface.
The smaller vessel with stand-pipe, Figures 2, 3, 4, and 5, consists of a cup B of
cast iron or other suitable metal with a recess d for the mercury, and of the glass
dome C with stand pipe D formed in one therewith, which dome fits with suitable
packing e on to the cup, against which it is pressed by means of the metal clamp E,
and screw F screwing through the cross bar G, Figures 2, 4 and 6. Two metal
tubes and g pass through the cup B, of which tubes the former forms part of the
tube connecting the two vessels, while the tube g serves for introducing the
required air and glycerine. The ends of both the tubes within the vessel are closed,
and the communication between them and the interior of the vessel is established by
means of a small lateral hole in the tube, the hole in f being situated near to the
upper end, while in g it is situated slightly below the upper surface of the
cup B.
The attachment of the tubes to the cup B is effected externally by flanges soldered
to the tube, and by packing rings h, while internally, screw nuts i are screwed on to
the threaded ends of the tubes, with interposition of a caoutchouc packing disc k
between the nut and the cup. This packing disc covers a small channel formed in
the surface of the cup B through which the air entering through the lateral opening

page_text: of g can pass into the vessel, the packing disc k being made to serve as a flexible
valve, which will allow the air to enter the vessel, but in closing the channel / will
prevent the air from escaping. The air is forced into the apparatus by means of a
hand air pump, which is temporarily attached to the curved tube g by means of a
flexible tube having a nozzle m, Figure 2, which is fitted to the tube g. When the
requisite amount of air has been forced in, a sufficient quantity of glycerine is intro-
duced through the same tube by another hand pump, for filling the vessel to a
level somewhat above the tops of the nuts i.
By this means the compressed air in the apparatus will be effectually retained by a
perfect hydraulic joint.
The end of tube g is then closed by a screw cap n and the apparatus is ready
for use.
Having now particularly described and ascertained the nature of this invention,
and in what manner the same is to be performed, I declare that what I claim
is :-
1. Apparatus for measuring and indicating temperatures at a distance constructed
and operating substantially as herein described with reference to the drawings.
2. The joint with liquid seal for the pipe f, substantially as described.
3. The vessel B and its accessaries, substantially as described.