IMPROVEMENTS IN THERMOSTATS
Year: 1886

page_text: We, GEORGE WESTINGHOUSE, Jr. and FRANK MOORE, both of Pittsburgh, in
the County of Allegheny, State of Pennsylvania, and United States of America,
Engineers, do hereby declare the nature of our invention for IMPROVEMENTS IN
THERMOSTATS and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
The object of our invention is to provide an apparatus of small compass and
simple and inexpensive construction whereby the temperature of an apartment may
be maintained at a substantially uniform determined temperature by the automatic
regulation of the supply of heating medium coincidently with and proportionately
to variations of temperature above or below the desired and determined degree.
To this end, our invention, generally stated, consists in the combination of a closed
case or chamber for the reception of a readily expensible liquid, said chamber being
connected to the chest or body of a regulating valve, a movable abutment closing
one end of said chamber, and a follower adapted to bear against the movable
abutment, and to transmit pressure therefrom, to the regulating valve.
improvement claimed is hereinafter fully set forth.
The
In the accompanying drawings: Figure 1, is a vertical central section through
a thermostat embodying our invention; and; Figs. 2 and 3, similar sections
illustrating modifications of certain details.
In the practice of our invention we provide a thin metallic chamber or receptacle
1, designed to be filled with any suitable liquid having a high degree of
expansibility, as for example, alcohol, benzine, or other liquid which vaporizes at a
low temperature, which chamber is most conveniently made, as shown, of cylindrical
form and is closed at one end by a cap 2, having an opening fitted with a suitable
plug 3, through which the liquid may be introduced. The opposite end of the
chamber 1, is fitted with a movable abutment adapted to be moved outwardly by
the pressure of the contained liquid when expanded and to be returned to position
upon the contraction of the liquid, a desirable form of such abutment being a
flexible diaphragm 4, soldered at its edges to the end piece 5, of the chamber 1.
The end piece 5, is connected to a follower chamber 6, which is formed integral
with or connected to the body or casing 7, of a regulating valve 8, controlling the
passage of a heating medium, as gas, to the apparatus by which heat is imparted to
[Price 8d1

page_text: the apartment in which the apparatus is located. The end piece 5, of the liquid
chamber may be connected adjustably to the follower chamber, as by a screw
thread on the periphery of the former engaging an internal thread in the latter in
order to enable the distance between the flexible diaphragm and regulating valve
to be increased or diminished as desired. The movable abutment 4, bears against
a follower which moves freely in the chamber 6, and which, as shown in Fig. 1, is
composed of a section 9, having one of its ends (abutting against the movable
abutment 4, and a section 10, which is connected to the section 9, by a nut 11,
engaging a thread on a central stem on the section 9, which passes freely through
the adjacent end of the section 10. A helical relieving spring 12, interposed
between the sections 9 and 10, and of sufficient tension to resist compression under
the pressure of the movable abutment; during such period as the regulating valve
is raised from its seat, maintains the outer faces of the sections 9, and 10, at the
maximum distance apart permitted by the adjustment of the nut 11. To prevent
leakage of fluid from the valve casing 7, past the follower, a flexible diaphragm 13,
may be interposed between the central opening of the follower chamber 6, and the
movable abutment 4, said diaphragm being secured centrally by a nut 14, to the
follower section 9, and at its periphery by a nut 15, to the chamber 6.
In the modifications shown in Figs. 2 and 3, in which the liquid chamber is fixed
without adjustment to the follower chamber, the follower 9, is formed in a single
piece having a broad head or upper face bearing against the movable abutment and
the relieving spring 12, is located at the opposite end of the liquid chamber, and
bears against a seat on the inside of the cap 2, and against a supplemental
follower 25, abutting against a flexible diaphragm 26, closing the upper end of the
liquid chamber and confined at its periphery between the same and the cap 2. The
stem 27, of the follower 25, which passes freely through the cap, is threaded at and
adjacent to its outer end, and is engaged by an adjusting nut 28, bearing against
the outer face of the cap. By this construction provision is made for the
adjustment of the apparatus to effect the maintenance of different degrees of
temperature by permitting the preliminary expansion of the liquid in the
chamber 1, to take place for a longer or shorter period without acting upon the
movable abutment 4, and through the same upon the regulating valve, the duration
of the inactive preliminary expansion depending upon the adjusted position of the
follower 25, by the nut 28. Provision is also made for such further expansion, if
any, of the liquid as may be occasioned subsequently to the seating of the
regulating valve, pressure being exerted in such case against the diaphragmn 26,
supplemental follower 25, and relieving spring 12, said spring serving the same
function of permitting such subsequent expansion as when interposed between the
two sections of a divided or composite follower, as in Fig. 1.
The pressure of the movable abutment 4, when moved outwardly by the
expansion of the liquid contained in the chamber 1, is transmitted by the
follower 9, 10, to the regulating valve 8, to wholly or partially close the same as
may be required to maintain the desired temperature, and, for the purpose of
increasing the sensitiveness of the apparatus, an increased degree of movement is
imparted to the regulating valve relatively to any given movement of the movable
abutment. In the instance illustrated, in Figs. 1 and 3, such increased traverse is
imparted to the valve through the intermediation of a lever system, the lower
section 10, or lower end of the follower, bearing upon a lever 16, of the third
order, pivoted by a pin 17, in the valve body, the outer end of said lever bearing in
turn upon a similar lever 18, working on a pivot 19, and the outer end of the lever
18, bearing upon a central projection on the top of the regulating valve 8. It will
be seen that by the employment of a system of levers as above, a slight degree of
movement of the abutment and follower will induce a materially increased
movement of the valve, and, consequently, that comparatively slight variations of
temperature will act effectively to regulate to the required degree the passage
of fluid through the opening controlled by the valve. It will be further obvious
that a lever system of different construction, or a single lever of unequal arms may,

page_text: if preferred, be employed to similarly effect the result of giving greater traverse
to the valve than that of the movable abutment.
In the modification shown in Fig. 2, the follower 9, is made integral with the
regulating valve 8, as an axial prolongation thereof, and bears at its upper end
against a flexible cylindrical extension 29, of a diaphragm 4, fixed between the
lower end of the liquid chamber 1, and the top of the follower chamber. 6, said
extension being of materially reduced transverse area relatively to that of the
liquid chamber, as, say, one eighth. The traverse of its lower face and of the
lower and regulating valve against which it abuts, will consequently be increased in
corresponding ratio above that which would be due to the pressure of a movable
abutment substantially equal in transverse area to that of the liquid chamber.
Upon the contraction of the fluid in the chamber 1, as induced by decrease of
temperature in the apartment, the regulating valve 8, is opened, to correspondingly
increase the supply of heating medium, by a helical supply spring 20, the tension
of which is less than that of the relieving spring 12, said supply spring bearing
against the supply side of the valve 8, and against the end of a central recess in a
stem 21, fixed in the valve casing 7, in line with the regulating valve, said stem
fitting a socket 22, on a bracket 23, which serves to secure the apparatus to any
suitable support, it being held in position, with the capacity of ready removal
when desired, by a nut 24, engaging a screw thread on the end of the stem 21.
In operation, where a divided follower and an adjustable liquid chamber are
employed, the sections 9 and 10, of the follower are adjusted by the nut 11, as may
be required to make the follower of proper length to transmit pressure to the
levers and regulating valve and the base piece 5, of the liquid chamber 1, is
connected to the top of the follower chamber 6, and fixed in position thereon by a
set screw 26, or other suitable locking device. The adjustability of the liquid
chamber to a greater or less distance from the regulating valve admits of the
ready adjustinent of the apparatus to effect the maintenance of different desired
degrees of temperature, by increasing or diminishing, as may be required, a portion
of the traverse of the movable abutment during which its action is not exerted
upon the regulating valve. Expansion of the liquid in the chamber by increase of
temperature of the apartment will correspondingly diminish the supply of heating
medium from the supply to the delivery side of the regulating valve, and upon the
contraction of the liquid, induced by decrease of temperature, the supply spring 22,
being relieved from the pressure of the moving abutment, will correspondingly
raise the valve from its seat and admit an increased supply of heating medium to
the apparatus by which the apartment is heated. The relieving spring 12,.acting
in connection with the sectional follower, admits of such further traverse of the
movable abutment 4, as may be induced by expansion of the liquid in the
chamber 1, subsequent to the seating or complete closure of the regulating valve,
the compression of the relieving spring in such case permitting the section 9, to
move towards the section 10, for such distance as may be required. Corresponding
facilities for adjustment for different temperatures and normal exertion of pressure
after the seating of the regulating valve, are afforded, as before explained, where
the relieving spring is employed in connection with a supplemental follower and
flexible diaphragın at the upper end of a non adjustable liquid chamber.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that
what we claim is:
1. The combination of a closed liquid chamber or receptacle, a casing or chest
connected to said chamber, a regulating valve working in the casing, a movable
abutment closing one end of the chamber, and a follower bearing against said
abutment and transmitting pressure therefrom to the regulating valve, substantially
as set forth.
2. The combination of a closed liquid chamber or receptacle, a regulating valve
working in a casing or chest connected therewith, and a device interposed between

page_text: '
the liquid chamber and valve for increasing the degree of traverse of the latter
under the action of pressure resultant upon the expansion of liquid contained in
the chamber, substantially as set forth.
3. The combination of a closed liquid chamber or receptacle, a regulating valve
working in a casing or chest connected thereto, a movable abutment closing one
end of the chamber, a follower bearing against said abutment, and one or more
levers adapted to transmit pressure from the follower to the regulating valve,
substantially as set forth.
4. The combination of a closed liquid chamber or receptacle, a regulating valve
working in a casing or chest connected therewith, a movable abutment closing one
end of the chamber, a follower bearing against said abutment and transmitting
pressure therefrom to the regulating valve, a movable abutment closing the
opposite end of the liquid chamber, a supplemental follower bearing against said
abutment and having a stem provided with an adjusting nut for regulating its
traverse, and a spring bearing against the supplemental follower and against a
fixed abutment, substantially as set forth.
5. The combination of a casing or chest, a regulating valve working therein and
adapted to control the passage of a heating medium from the supply to the
delivery side thereof, a closed liquid chamber connected adjustably to the valve
casing so as to be fixed at a greater or less distance therefrom, a movable abutment
closing one end of said chamber, and a follower bearing against said abutment, and
transmitting pressure therefrom to the regulating valve, substantially as set forth.
6. The combination of a closed liquid chamber or receptacle, a regulating valve
working in a casing or chest connected thereto, a movable abutment closing one
end of the chamber, a follower composed of two sections connected with the
capacity of relative longitudinal movement, one of said sections adjoining the
movable abutment, and the other bearing against the regulating valve and a
relieving spring interposed between the follower sections, substantially as set forth.
7. The combination of a casing or chest, a regulating valve working therein and
adapted to control the passage of a heating medium from the supply to the
delivery side thereof, a closed liquid chamber connected to the valve casing,
movable abutment closing one end of said chamber, a follower working in a
passage leading from the valve casing to the movable abutment and transmitting
pressure from said abutment to the regulating valve, and a flexible diaphragm
connected at its centre to the follower and at its periphery to the casing within
which the same is enclosed, substantially as set forth.
&
8. The combination of a closed liquid chamber or receptacle, a movable abutment
closing one end of said chamber, a valve casing connected to the abutment end of
said chamber, a regulating valve working in said casing, a follower bearing against
the movable abutment and transmitting pressure therefrom to the regulating valve,'
a removable plug or stem closing an opening in the valve casing in line with the
regulating valve, and a bracket for supporting the apparatus, having a socket to
receive said plug or stem, substantially as set forth.
Dateri
LA GULCINI LILY L
AYOVPINA
Witnesses:
J. SNOWDEN BELL,
R. H. WHITTLESEY,
GEO. WESTINGHOUSE, JR.
FRANK MOORE.
Abel & Imray,
Agents for the Applicants.