A Method of Indicating at One Station Temperatures or Atmospheric Pressures Existing at Various Places, and Apparatus for that Purpose.
Year: 1892

page_text: Date of Application, 30th Nov., 1892-Accepted, 4th Feb., 1893
COMPLETE SPECIFICATION.
A Method of Indicating at One Station Temperatures or Atmospheric
Pressures Existing at Various Places, and Apparatus for that
Purpose.
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 :-
My invention relates to means enabling a person at one point or station to
ascertain the temperature or atmospheric pressure at another point or points, as for
instance, in the various rooms of a building, or in the various workings of a mine
or in other situations.
Apparatus for this purpose is susceptible of considerable variation, but, in a
practically convenient form, it comprises for each room or situation a thermometer
or barometer with a series of contacts corresponding to different degrees of tem-
perature or pressure within a desired range, a corresponding number of electrical
signals, conductors connecting the contact points of the thermometer or barometers
with connections to the signals, suitable return conductors, a battery or other
supply of electricity, and a switch and commutator by which the various circuits
can be opened or closed at the indicator station.
Fig. 1 of the accompanying drawings is a sectional perspective view showing six
rooms of a building, four of them furnished with thermometer G, and a fifth
containing the indicator or signalling apparatus C. Fig. 2 is an outside view, and
Fig. 3 an inside view of one form of the signal box or case.
Fig. 4 is a front view of a mercurial thermometer. Fig 5 is a front view of a
metallic thermometer.
'
Fig. is a diagram of suitable electrical connections.
Fig. 7 is an outside view, Fig. 8 an inside view and Fig. 9 a vertical section of
an indicator provided with incandescent electric lamps.
Fig. 10 is a diagram of the connections for these and Figs. 11 and 12 are
respectively an elevation and a section of a commutator suited for four compart-
ments, each having a thermometer provided with four contact points for different
temperatures.
1, 2, 3, 4 and 5 indicate different apartments in a building A, 1 containing, it
may be, heating apparatus B, and the indicating apparatus C for shewing the
temperature in the different apartments 2, 3, 4 and 5.
In the indicating apparatus shewn in Figs. 2 and 3 Geissler tubes are employed
whilst, as shewn in Figs 7, 8 and 9, incandescent electric lamps are used.
Referring to Figs. 2 and 3, C is a casing containing four Geissler tubes a, b, c
and d there being four indications required for each apartment.
D is an induction coil and E a battery of suitable size and kind, which may be
dispensed with when electricity can be obtained from a service main or other
source.
On the front of the casing is a dial F containing as many sets of contacts as
there are apartments connected with the apparatus (in the present instance four)
each set comprising as many contact points as there are temperatures (also in this
instance four) to be indicated for each apartment.
Each of the apartments 2, 3, 4 and 5 contains a thermometer G, of which two
forms are represented in Figs. 4 and 5 respectively, that in Fig. 4 being a mercurial
thermometer, and that in Fig. 5 being a metallic thermometer comprising compound
bars deflected by variations of temperature.

page_text: The thermometer Fig. 4 comprises a thermometer tube pierced for the introduc-
tion of wires e, f, g, h, at points corresponding to the different degrees of tempera-
ture to be indicated, such as 60°, 65°, 68° and 70°.
The tube is also pierced at a lower point for the introduction of a wire i to
complete the circuit.
The tube is supplied with mercury; so long as the mercury remains below
the 60° wire, no circuit is completed, but when the column rises to make contact
with the wire ha circuit is completed between the wires h and i, and so on succes-
sively in respect of the wires gf and e. When the last wire e is touched by the
mercury, the four circuits are all closed.
The thermometer in Fig. 5 consists of a set of compound bars j k l m each of
which may be of brass and steel, steel and zinc, or any known combination of
substances having different rates of expansion by temperature. Each of these bars
is adjusted so as to make contact with a screw stud n at a certain temperature, and
so to complete a circuit of wire i with e f g or h.
As shown in Fig. 6, G¹ G2 G3 and G indicate the thermometers of the four
apartments 2, 3, 4 and 5. From each thermometer the four wires e f g h are led
to the commutator F and through its face terminating in four sets of circularly
arranged contact points o.
As shewn more clearly in Figs. 10 and 11, a radial arm H carries four contact
springs p spaced to correspond with the spacing of the contact points o of each set.
The arm H also carries four wires grst each connecting one of the fingers p
with one of the Geissler tubes a b c d of Figs 2 and 3, or with one of the
incandescent electric lights a, b, c, d¹ of Figs. 7, 8, 9 and 10.
i indicates the return wire from the thermometers G1 G2 G³ and G', which
connects with the several Geissler tubes through the medium of the induction
coil D, or with the incandescent electric lights through the battery or other source
of electrical energy.
J is a switch preferably a spring push button by which the circuit of the
indicator may be closed or opened.
The construction of the commutator may be varied. As shewn in Figs. 11
and 12 a circular shell K of wood or other insulating material is hollowed out
to receive the working parts, and has in its recess an annular plate L of
vulcanite or other like insulating material, through which are led stems o the
ends of which constitute the contact points and to which are clamped the
insulated wires e f g h.
A central metal spindle M turned by a handle N has fixed on it a collar O of
non conducting material on which are fixed the contact springs or fingers p. The
spindle M is hollowed, having passed through it the insulated wires q r s t connect-
ing to the Geissler tubes or the incandescent lamps, these wires being sufficiently
free to allow of the spindle M being turned half round or
overstraining them. The front of K is covered with a glass plate.
The operation of the apparatus is as follows:
more without
Assuming that the handle N is turned so that the fingers p do not make contact
with any of the points o and that the switch J is in position opening the circuit,
the operator desiring to ascertain the temperature in a given room, closes the
circuit by the switch J and turns the handle N until the springs p bear upon
the set of contacts o which corresponds to the room the temperature of which
is to be ascertained.
Thereupon the wires e f g h of the thermostat of that room being thus con-
nected to one, two, three or four of the Geissler tubes or incandescent lamps they
become luminous, according as the temperature has reached the first, second, third,
or fourth of the degrees for which the contacts of the thermostat are arranged.
To save battery power, a single compound bar, which may be bent to volute
form may carry at its end a spring contact, which, sliding over a series of
contact plates will make electrical connection with one or other of these so that

page_text: only the circuit of the tube or lamp corresponding to the particular temperature
will become luminous.
Besides Geissler tubes or electric lamps, other known forms of signals, semaphores,
bells or the like, may be employed.
Also the several signals may be distinguished
in various ways, as for instance, by placing the Geissler tubes indicating the
higher temperatures above those indicating the lower temperatures, by colouring
the tubes or lamp bulbs differently; or by lettering or numbering them to denote
the different degrees of temperature.
To provide against injury to the Geissler tubes or to the electric lamps it is
preferred to support them by light springs v, as indicated in Figs. 3, 7, 8 and 9.
The switch J is not essential, as all the circuits can be opened by turning the
handle N, but J is useful as a means of preventing undue waste of electricity if
the circuit should be left closed through the contacts o and springs p.
The wires e f g h may be twisted together in the usual way and led as a cable
to the points where they have to separate to their respective apartments.
I have above described my invention as applied for indicating temperatures, but,
obviously, by employing the same electrical signals, switch, commutator and
conductors, and making the mercurial contacts in a barometer tube instead of a
thermometer tube at each place, the apparatus will serve to indicate the atmospheric
pressure at that place. In order to magnify the intervals between the contact
wires in the barometer it may be inclined.
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:-
1. The herein described method of indicating at one station temperatures or
pressures existing at various places, by connecting several electric contacts of a
thermometer or barometer situated in each of those places by insulated con-
ductors to a group of corresponding stationary contacts on a commutator, and by
means of moveable contact springs of the commutator bringing any one of those
groups into circuit with Geissler tubes, incandescent lamps or any known electrical
signals provided as many in number as there are contacts in the group, one or more
or one or other of the set of tubes, lamps or signals being thus actuated according
as the distant thermometer or barometer corresponding to the selected group of
contacts is affected by one or other of the several temperatures or pressures for
which its contacts are adjusted.
2. For indicating temperatures or pressures in the manner above referred to,
combined apparatus consisting of a thermometer or barometer situated in each
place at which the temperature or pressure is to be indicated, and provided with
several electrical contacts which are made at different temperatures or pressures, a
commutator having as many groups of fixed contacts as there are thermometers or
barometers, each group on the commutator consisting of as many contacts as there
are contacts at the thermometer or barometer, and the moveable part of the com-
mutator having the same number of contact springs, an equal number of Geissler
tubes, incandescent lamps or other electrical signals, with a battery or other source
of electricity and the necessary conductors, arranged and operating substantially
as described.
Dated this 25th dor of November 1809
ABEL & IMRAY,
Agents for the Applicant.