Improvements in Thermostatic Instruments.
Year: 1893

page_text: Date of Application, 6th June, 1893
Complete Specification Left, 6'h Mar., 1894-Accepted, 19th May, 1894
Improvements in Thermostatic Instruments.
A communication from abroad by GEORGE WILLIAM GREGORY, of 34, School
Street, Boston, Massachusetts, in the United States of America, Patent
Solicitor.
I, Alfred GEORGE BROOKES of 55 & 56 Chancery Lane, in the County of
London, Chartered Patent Agent do hereby declare the nature of this invention
to be as follows:-
This invention relates to thermostatic instruments, especially adapted to be
employed in automatic fire alarm systems.
The present invention has for its object to provide a simple and efficient
thermostatic instrument, especially adapted to be used in localities, where it is
desired that the instrument should operate at a substantially low heat.
In thermostatic instruments as now commonly made, a fusible solder is
employed having a substantially low melting point, and it has been demonstrated
by practical experience, that a solder having a melting point lower than about
150° Fahrenheit does not possess the necessary strength to enable it to be used
practically.
The present invention has for its object to provide a thermostatic instrument,
in which an active member, capable of being expanded or distorted by heat, is
attached to a support therefor, which may be a circuit-terminal carrying body, by
one or more fusible connections preferably solder, so that when the temperature
has reached a predetermined point, which is lower than the melting point of the
solder, the said active member will be expanded or distorted and the fusible
solder ruptured, thereby operatively disconnecting the said active member from
its support.
The thermostatic instrument is especially adapted to be used in an electric
circuit and form an electro-thermostatic instrument, which when operated, gives
an alarm that the electric circuit is opened.
The expanding active member referred to, is preferably made as a hermetically
sealed vessel or capsule, preferably containing a volatilizable fluid, such as ether,
and the said vessel is attached, as herein shown, to an electric-terminal-supporting
body, it being preferably directly secured to the said body, by a fusible material,
preferably solder, the said capsule being preferably secured directly to the
circuit-terminals, and forming a part of the electric circuit.
The fluid or medium contained in the vessel or capsule, is of such nature that
it will volatilize at a lower heat than the melting or fusing point of the solder,
and expand the hermetically sealed vessel and rupture the connection between the
same and the circuit-terminals, and the said vessel or capsule will be forced away
from the terminal supporting body, thereby opening the electric circuit at a
temperature lower than the melting point of the solder.
One form of support or circuit-terminal-carrying body, may be a disk of
insulating or non-conducting material, provided with substantially diametrically
opposite ears.
The body has secured to it, circuit-terminals, preferably hollow tubes extended
into or otherwise secured to conducting tubes extended down through the ears.
The circuit-terminal-carrying body, has attached to it the active member of the
improved thermostat, which active member is preferably a hermetically sealed
vessel or capsule, preferably containing within it a volatilizable fluid such for

page_text: instance as ether, the top or upper side of the said vessel being flexible and
preferably concaved to permit the said top or upper side to be bulged out, when
the fluid is volatilized.
The vessel or capsule is preferably included in the electric-circuit, and is
preferably directly secured to the body by fusible connections, such as fusible
solder, filling the conducting tubes.
The body of the insulating body is preferably made slightly convex.
Hollow terminals are adapted to receive within them, the ends of the line wires
of an electric circuit, and the said terminals may be electrically connected to the
wires referred to, by crimps or bends.
The fusible material or solder electrically connects the hollow terminals with
the vessel, and when the thermostat is placed in operative position, the circuit may
be supposed to pass from the one terminal through the one conducting tube, the
fusible solder, the sealed vessel, solder and the other conducting tube to the other
terminal.
In practice, the fluid volatilizes at a lower temperature than that at which the
solder or material fuses or melts, so that when the fluid is expanded by a rise in
temperature, such as caused by the breaking out of a fire in a building or other
structure, the cover or top of the vessel will be forced against the body by the
expanding fluid, and when the said cover has obtained a solid bearing on the body,
the still expanding fluid will force the vessel away from the body and thereby
rupture the fusible connections before the latter have been melted or fused
thereby opening the electric circuit at a lower temperature than that at which the
fusible connection melts.
In practice it is desirable in many cases to have an alarm of fire at a lower
temperature than 150° Fahrenheit and with the fusible thermostats as now con-
structed and known to my correspondent, this result cannot be obtained.
In the improved thermostat the solder is weakened by even a substantially slight
rise in temperature, and is therefore put into condition to be readily ruptured,
when the active member is operated upon by heat.
Furthermore it will be noticed, that in case the active member should fail to
operate, for any cause, the fusible solder would operate and open the electric
circuit at the temperature at which the solder melts.
Dated the 6th day of June 1893.
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Thermostatic Instruments.
A communication from GEORGE WILLIAM GREGORY, of 34, School Street,
Boston, Massachusetts, in the United States of America, Patent Solicitor.
1 ALFRED GEORGE BROOKES of 55 & 56 Chancery Lane in the County of
London, Chartered Patent Agent 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 tollowing statement :-
This invention relates to thermostatic instruments, especially adapted to be
employed in automatic fire alarm systems.
The present invention has for its object to provide a simple and efficient thermo-
static instrument, especially adapted to be used in localities, where it is desired that
the instrument should operate at a substantially low heat.
In thermostatic instruments as now commonly made, a fusible solder is employed
having a substantially low melting point, and it has been demonstrated by practical

page_text: experience, that a solder having a melting point lower than about 150° Fahrenheit
does not possess the necessary strength to enable it to be used practically.
The present invention has for its object to provide a thermostatic instrument, in
which an active member, capable of being expanded or distorted by heat, is
attached to a support therefor, which may be a circuit-terminal carrying body, by
one or more fusible connections preferably solder, so that when the temperature has
reached a predetermined point which is lower than the melting point, of the solder,
the said active member will be expanded or distorted and the fusible solder
ruptured thereby operatively disconnecting the said active member from its
support.
The thermostatic instrument is especially adapted to be used in an electric
circuit and form an electro-thermostatic instrument which when operated, gives an
alarm that the electric circuit is opened.
The expanding active member referred to, is preferably made as a hermetically
sealed vessel or capsule, preferably containing a volatilizable fluid, such as ether,
and the said vessel is attached, as herein shewn, to an electric-terminal-supporting
body, it being preferably directly secured to the said body, by a fusible material,
preferably solder, the said capsule being preferably secured directly to the circuit-
terminals, and forming a part of the electric circuit.
The fluid or medium contained in the vessel or capsule, is of such nature that it
will volatilize at a lower heat than the melting or fusing point of the solder, and
expand the hermetically sealed vessel and rupture the connection between the same
and the circuit-terminals, and the said vessel or capsule will be forced away from
the terminal supporting body, thereby opening the electric circuit at a temperature
lower than the melting point of the solder.
The particular features of the invention will be pointed out in the claims at the
end of this Specification.
Fig. 1 is a perspective view of a thermostatic instrument embodying the
invention, and
Fig. 2, a longitudinal section of the instrument shewn in Fig. 1.
A represents one form of support or circuit-terminal-carrying body, it being
herein shewn as a disc of insulating or non-conducting material, provided with
substantially diametrically opposite ears a, a¹.
The body A has secured to it, as herein shewn circuit-terminals, preferably
hollow tubes a², a³, herein shewn as extended into or otherwise secured to conducting
tubes a, a, extended down through the ears a, a¹.
The circuit-terminal-carrying body, has attached to it the active member of the
improved thermostat, which active member is herein shewn as, preferably, a
hermetically sealed vessel or capsule b, preferably containing within it a volatizable
fluid such for instance as ether, the top or upper side of the said vessel being
flexible and preferably concaved, as shewn in Fig. 2, to permit the said top or
upper side to be bulged out, when the fluid is volatilized.
The vessel or capsule is preferably included in the electric circuit, and is
preferably directly secured to the body A by fusible connections, such as fusible
solder b² which is herein represented as filling the conducting tubes a', aº.
The bottom of the insulating body A is preferably made slightly convex, as
shewn in Fig. 2.
The hollow terminals a², a³ are adapted to receive within them, the ends of the
line wires of an electric circuit, not herein shewn, and the said terminals may be
electrically connected to the wires referred to, by crimps or bends.
The fusible material or solder 2, as herein shewn, electrically connects the
bollow terminals a², a with the vessel A and when the thermostat is placed in
operative position the circuit may be supposed to pass from the terminal a³ through
the tube a', the fusible solder 6, the vessel b, solder *, and the tube a³ to the
terminal a³.
In practice, the fluid volatilizes at a lower temperature than that at which the
solder or material b³ fuses or melts, so that when the fluid 6' is expanded by a rise

page_text: in temperature, such as caused by the breaking out of a fire in a building or other
structure, the cover or top 6' of the vessel will be forced against the body A by the
expanding fluid, and when the said cover has obtained a solid bearing on the body A,
the still expanding fluid will force the vessel b away from the body A and thereby
rupture the fusible connections 2, before the latter have been melted or fused,
thereby opening the electric circuit at a lower temperature, than that at which the
fusible connection melts.
In practice it is desirable in many cases to have an alarm of fire at a lower
temperature than 150° Fahrenheit and with the fusible thermostats as now
constructed and known to my correspondent this result cannot be obtained.
In the improved thermostat the solder is weakened by even a substantially slight
rise in temperature, and is therefore put into condition to be readily ruptured, when
the active member is operated upon by heat.
Furthermore it will be noticed, that in case the active member should fail
to operate, for any cause, the fusible solder would operate and open the electric
circuit at the temperature at which the solder melts.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. In a thermostatic instrument, the combination with an expausible active
member, adapted to exert pressure on an increase in temperature, and a support for
said active member, of a fusible connection attaching said active member to the said
support and normally under substantially little tension by said active member but
adapted to be ruptured by the increased expansive action of the active member, due
to a rise in temperature, substantially as described.
2. In a thermostatic instrument, the combination with a circuit terminal-carrying
body, of an expansible active member, adapted to exert pressure on an increase in
temperature and one or more fusible connections attaching said active member to the
said body, the said fusible connections being normally under substantially little
tension by said active member but adapted to be ruptured by the increased
expanding action of the active member due to a rise in temperature, substantially
as described.
3. In a thermostatic instrument, the combination with a circuit terminal-carrying
body, of an active member detachably attached to the said body, and consisting of a
vessel containing a volatilizable fluid, adapted to volatilize at a substantially low heat
and a fusible connection joining the said vessel to the terminal carrying body and
which is ruptured by the expanding action of the vessel to open the electric circuit
between the said terminals, substantially as described.
4. In a thermostatic instrument, the combination with an insulating body
provided with hollow circuit-terminals a², a³ of an expansible active member, and
fusible connections joining said active member to the said body and electrically
connecting the said member with the hollow terminals, substantially as described.
5. In a thermostatic instrument, the combination with the insulating body A
having ears a, a', of circuit terminals secured to said ears, tubes extended through
the ears and to which the said circuit terminals are connected, a fluid containing
vessel b, and fusible solder securing the vessel to the insulating body A and
electrically connecting the said vessel with the circuit terminals, substantially as
described.
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WM. BROOKES & SON,
55 & 50, Chancery Lane, London, Agents for the Applicant.