An Improvement in Apparatus for Indicating at One Station Temperatures or Atmospheric Pressures Existing at Various Places.
Year: 1893

page_text: Date of Application, 17th Jan., 1893
Complete Specification Left, 3rd May, 1893—Accepted, 2nd June, 1893
PROVISIONAL SPECIFICATION.
An Improvement in Apparatus for Indicating at One Station
Temperatures or Atmospheric Pressures Existing at Various
Places.
I, JAMES BARTLETT, of Buckingham House, Finsbury Park, in the County
of Middlesex, Engineer, do hereby declare the nature of this invention to be as
follows:-
In my Specification No. 21905 of 1892 I described means of electrically
indicating at one station temperatures or atmospheric pressures existing at various
places. For that purpose I placed in each of the various places a thermometer or
barometer having conducting pins sealed into its tube at several different heights
and from each of those pins I led a separate conducting wire to the station, where
by means of a commutator all the wires of the group from any one of the instru
ments except those from the pins that were then above the mercury level, were
brought into circuit with indicators such as various coloured glow lamps by which
the height of the local mercury column was indicated. According to my present
invention, instead of leading a group of separate wires from the conducting pins of
each instrument, I lead a single wire to the station, but this wire is led from
successive resistances to which the conducting pins are connected, so that the
electromotive force of the current conveyed by the wire diminishes by steps as the
mercury descends along the scale of the instrument or conversely. At the station
the wire from any one of the distant instruments can, by means of a commutator,
be brought into circuit with an indicator in the form of a galvanometer, the index
of which will point on a dial to a graduation corresponding with the height of the
highest conducting pin reached by the mercury in the distant thermometer or
barometer tube.
Dated this 17th day of January 1893.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improvement in Apparatus for Indicating at One Station
Temperatures or Atmospheric Pressures Existing at Various
Places.
I, JAMES BARTLETT, of Buckingham House, Finsbury Park, in the County of
Middlesex, Engineer, 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 :-
In my Specification No. 21905 of 1892 I described means of electrically
indicating at one station temperatures or atmospheric pressures existing at various
places. For this purpose, I placed in each of the various places a thermometer
or barometer having conducting pins sealed into its tube at several different
heights, and from each of those pins led a separate conducting wire to the
station, where by means of a commutator all the wires of the group from any one
of the instruments, except those from the pins that were then above the mercury
level, were brought into circuit with indicators such as various coloured glow lamps
by which the height of the local mercury column was indicated. According to my
present invention, instead of leading a group of separate wires from the conducting
pins of each instrument, I lead a single wire to the station, but this wire is led

page_text: through successive resistances to which the conducting pins are connected, so that
the electromotive force of the current conveyed by the wire diminishes by steps as
the mercury descends along the scale of the instrument or conversely. At the
station, the wire from any one of the distant instruments can, by means of a
commutator, be brought into circuit with an indicator in the form of a galvanometer,
the index of which will point on a dial to a graduation corresponding with the
height of the highest conducting pin reached by the mercury in the distant
thermometer or barometer tube.
Fig. 1 of the accompanying drawings is a front view of a thermometer placed in
one of the apartments, which may be at a distance, and Fig. 2 is an elevation
of the instrument in the central station on which the temperature is indicated.
A wire W connects to the mercury M at some point below the lowest tem-
perature to which the instrument is subject, and other wires W1 W2 &c. connect to
the mercury at points corresponding to the several temperatures which it is desired
to indicate. Each of those wires except the last W' is connected to a
resistance R' R2 &c. which are all connected in series along with W7 to W8. There
are a number of wires W, say 12, from different apartments each of which is
connected to one of the contacts C of the commutator, over which the rubber or
brush B can he turned by hand. This brush is connected, inside the casing of the
indicator, through a switch S and the coil of a galvanometer G, to one terminal of
a battery from the other terminal of which wires W are led to the instruments in
the several apartments. It will be seen that the circuit by the wire W7 corre-
sponding to the highest temperature does not pass through any resistance, that
of W passes through one, namely R, that of W5 passes through two namely R$
and R, and so on, so that the electrical current determined by the closing of the
circuit at the higher temperatures causes greater deflection of the galvanometer
index than in the case of the lower temperatures. The apparatus is thus worked.
Normally the switch S, which is like those used for electric bells, by means of a
spring keeps the circuits open. When it is desired to ascertain the temperature in
one of the rooms, say 10, the operator turns the brush B till it bears on the
contact C which is marked 10; he then presses the knob of the switch S thus
closing the circuit from one terminal of the battery through W, M, W', R', R' &c.
R, W, contact 10, rubber B, switch S and coil of G to the other terminal of the
battery. The index of G is thus made to point to 50, shewing that the temperature
in room 10 is above 50° but under 55°, the wire W' corresponding to 55° being
above the mercury and therefore being out of the circuit.
Obviously the height of mercury in a barometer might be similarly indicated.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
In apparatus for indicating at one station, temperatures or atmospheric pressures
existing at various places, in combination with a thermometer or barometer at each
place and wires sealed into its tube at various heights, a number of resistances
arranged in series with these wires, and, connected therewith at the central station,
a switch, commutator, galvanometer and battery arranged and operating substantially
as described.
Dated this 2nd dor of Mar 1902
ABEL & IMRAY,
Agents for the Applicant.