Improvements in Automatic Water Heaters
Year: 1898

page_text: Date of Application, 28th July, 1898-Accepted, 12th Nov., 1898
COMPLETE SPECIFICATION.
Improvements in Automatic Water Heaters,
I, EDWIN RUUD, Mechanical Engineer, residing at No. 130, Linden Avenue,
in the City of Pittsburg, in the County of Allegheny, State of Pennsylvania,
United States of America, 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:-
The object of my invention is to provide an improvement in automatic water
heaters; and to this end, my invention consists in an improved automatic water
tube or coil heater, in which the supply of heat is regulated by variations in the
temperature of the water in the heating coil; and in which the supply of gas to
a burner or burners in a gas heating apparatus controlled by a thermostat, may
be automatically cut off upon the extinguishment of flame at the burner, as may
happen by accident, carelessness, or temporary cessation of gas supply and
thereby to effectually prevent the liability to serious accident and damage
resultant upon the escape of a substantial volume of gas from a burner or burners.
In the accompanying drawings, which illustrate my invention, Figure 1 is a
central vertical section through my improved heater; Fig. 2, a view, partly in
side elevation and partly in section, and on an enlarged scale, of a portion of
the construction shown in Figure 1; Fig. 3, a view at right angles to that shown
in Figure 2; and Fig. 4, a sectional view, illustrating a modification of my
invention in which an independent cut-off valve is used.
In the construction shown in Figure 1, the coil of heating pipe, 1, is enclosed
within a casing, 2, and either terminal, «, or b, of the coil may be connected
with a cold water supply pipe through which cold water may flow into the coil,
and the other with the hot water discharge pipe, chamber, or vessel, from which
hot water may be drawn for use.
My invention is specially adapted to be employed in dwelling-houses, hotels,
or other places, where an instantaneous supply of hot water may be desired on
opening one or more faucets or valves at any point in the house at which the
water is required, or where a continuous supply of hot water is desired.
The number of discharge pipes leading from the coil and through which hot
water is drawn, is immaterial, as is also the outer arrangement of pipes to which
the terminals of the coil are connected.
Below the heating coil, inside of the base, 3, is placed a burner, or burners, 4,
for supplying heat to the coil. The supply of gas to the burner, or burners,
is controlled, or regulated, by a thermal regulating device, or thermostat, which
is placed in circuit with the heating coil. The form of this thermostat is not
limited to any particular construction, but as shown in the drawing, an outer
tube, 12, is connected at, or near, its opposite ends with portions of the coil, 1,
which extend above and below the tube, 12; the space within the tube, 12,
forming a continuation, or a portion of the coil, 1, through which water may
circulate when passing from one terminal of the coil to the other.
Within the tube, 12, is a tube, 13, formed of material having preferably, a
comparatively great coefficient of expansion, and being secured at one end to a

page_text: stationary part of the thermostat. Within the tube, 13, is a rod, 14, preferably
composed of less expansible material than the tube, 13, and which bears at one
end against the inner end of the tube, 13, and at the outer end against. a lever, 15,
which is outside of the tube, 13, in position to engage with the adjusting
Borew, 16, of the lever, 16, which actuates a lever, 44, with a valve, 7, for con-
trolling the supply of gas to the burners, 4.
In the normal operation of the device, the levers, 16, and 44, are moved in one
direction by the lever, 15, and in the opposite direction by the spring, 19, and
they move the valve, 7, away from, or permit its movement towards, its seat;
the lever, 44, being in engagement at one end, with the adjusting nut, 17, on
the valve stem, 18.
If we suppose the thermostat to be adjusted so as to maintain the supply of
hot water at a certain temperature, and for any reason there should be an in-
crease above the desired temperature, the tube, 13, will expand, the rod, 14,
will be moved to the left by the levers, which are actuated by the spring, 19,
and the valve, 7, which is acted on by the same spring, will be moved towards its
seat, and partially or wholly closed, so as to reduce or entirely cut off the supply
of gas to the burners, 4. If any reduction in the temperature of the water in
the coil, below that for which the thermostat is adjusted, should take place, the
tube, 13, will contract, the rod, 14, will be moved outward to the right, the
levers will unseat or more fully open the valve, 7, and permit, or increase, the
flow of gas from the supply pipe, 6, to the burners, 4.
•
In ordinary operations, the changes of temperature, which act through the
thermostat, to effect variations in the supply of heat, will be due to the with-
drawal of the water from the pipes, and coil, through the faucets or valves, and
the consequent flow of cooler water into the coil; but my improvement is adapted
to maintain the supply of water at the desired temperature at all times regard-
less of the causes which operate to regulate the supply of heat, and the variations
of the heat supply may be effected in accordance with the variations in the
temperature of the atmosphere without any withdrawal of water from the pipes,
or coil.
In the ordinary employment of my heater, an increase in the supply of hent
will be caused by opening one or more of the faucets or valves through which
hot water is to be drawn, the current of cold water, which will then flow into
the coil, causing the operation of the thermostat, and the increased opening of
the gas supply valve.
The most important feature of my improvement is the combination with the
heating coil of a thermal regulating device in, or in circuit with, the heating
coil, and forming a part of the heating coil through which the water passes in
being heated; or which is connected to, or forms a loop, or by-pass, connected
with a part of the heating coil which is directly exposed to the heat, the supply
of which heat is controlled by the thermal regulating device. My improve-
ment provides a practically instantaneous heater, the automatic control, or
regulation of which is, or may be, effected by comparatively great variations
in the temperature of the water.
My improvement dispenses with the usual large boiler, or other reservoir of
heated water which has heretofore been employed and which is usually main-
tained at considerable expense, and provides, with the simplest possible construc-
tion, an automatic instantaneous heater, which practically consists only of a
heating coil and a thermostat, or heat regulating device by means of which the
water is heated, as fast as it is drawn from the pipes. This rapid heating is due,
principally, to the rapid and considerable variations which may be effected in
the supply of heat during the correspondingly great and rapid variations of
temperature to which the thermostat is subject on account of its location in the
coil.
Another important feature of my invention is the means by which the supply
of gas from the service pipe either to the main burners alone, or to both the

page_text: controlling the flow of gas to said burner and arranged in a chamber forming a
part of the outlet from the water receptacle and so located as to be directly
subjected to the heat from the burner.
5. The combination, substantially as set forth, of a gas burner, a valve con-
trolling the supply of gas thereto, a spring bearing on said valve with a constant
tendency to effect its closure, a thermostat normally subjected to the heat of a
gas burner, connections from said thermostat to said valve, acting in opposite
direction to said spring, and a tripping device actuated by said thermostat for
releasing said connections.
6. The combination, substantially as set forth, of a main gas burner, an inde-
pendent or pilot burner, a valve controlling the supply of gas to the main
burner, a thermostat normally subjected to the heat of the pilot burner and
unaffected by the main burner, and mechanism, connected with and actuated
by said thermostat, for effecting the automatic closure of the valve upon the
extinguishment of the flame at the pilot burner.
7. The combination, substantially as set forth, of a main gas burner, an inde-
pendent or pilot burner, a valve controlling the supply of gas to the main burner,
a thermostat normally subjected to the heat of the pilot burner and unaffected
by the main burner, a closing spring bearing on the valve with a constant
tendency to effect its closure, connections from the thermostat to the valve,
acting in opposite direction to the closing spring, and a tripping device by which
said connections are automatically released, and the spring caused to close the
valve, in and by the contraction of the thermostat resultant upon the extinguish-
ment of the flame at the pilot burner.
8. The combination, substantially as set forth, of a main gas burner, an inde-
pendent or pilot burner, a main supply valve controlling the supply of gas to the
main burner, a thermostat normally subjected to the heat of the pilot burner
and unaffected by the main burner, an independent cut off valve controlling the
supply of gas to the main and pilot burners, and mechanism, connected with and
actuated by said thermostat, for effecting the automatic closure of the independent
cut off valve upon the extinguishment of the flame at the pilot burner.
9. The combination, substantially as set forth, of a main gas burner, an inde-
pendent or pilot burner, a valve controlling the supply of gas to the main burner,
& thermostat normally subjected to the heat of the main burner, said thermostat
being connected with and regulating the movement of said valve, a supplemental
thermostat subjected to the heat of the pilot burner and unaffected by the main
burner, and mechanism, connected with and actuated by said supplemental
thermostat for effecting the automatic closure of the valve upon the extinguish-
ment of the flame at the pilot burner.
Dated at Pittsburg. Pennsylvania. this 27th day of June A D 1898
Witnesses:
WILLIAM G. DOOLITTLE.
THOMAS J. HOGAN.
EDWIN RUUD.

page_text: communication between the service pipe, 6, and a pipe 6*, leading to the valve
chest, (not shown) of a main or ordinary gas supply valve, from which supply
pipes 10 and 11 lead to the main burners, 4, and the pilot burner, 5, as in the
instance first described, said supply valve being controlled by a main ther-
mostat, 12, 13, 14, in the ordinary or any other preferred manner. A supple-
mental thermostat, 40, similar to that before described, is located in position
to be subjected to the heat of the pilot burner, 5, and is secured, at one end,
to a suitable support, as the base, 3, of the heater. The opposite end of the
supplemental thermostat, 40, is coupled to one arm of the tripping lever, 42ª,
which, in this case, is in the form of a bell crank and the other arm of the
tripping lever is provided with a shoulder or projection, which bears against one
arm of a double armed lever, 52, journalled in a bracket, which may be con-
veniently secured to the valve chest, 50. The opposite arm of the lever, 52,
engages a notch or recess, in the outer portion of the stem, 53, of the cut off
valve, 51, and so long as the thermostat, 40, is expanded by the heat of the pilot
burner, the cut off valve is hold open for the passage of gas, by the engagement
of the levers 42", and 52, and the valve stem, 53. Upon the extinguishment of
the flame at the pilot burner, the resultant contraction of the thermostat draws
the tripping lever, 42", out of engagement with the lever, 52, and the cut off
valve, 51, is immediately closed or brought to its seat by the closing spring, 54,
thereby cutting off the flow of gas from the service pipe, 6, to the chest of the
main gas supply valve, and consequently cutting off the supply of gas to both the
main burners and the pilot burner.
A special feature of advantage in the operation of apparatus embodying..my
invention, is the quickness of its action, due to the prompt contraction of the
supplemental thermostat upon the extinguishment of the pilot burner flame.
The supply of gas to the burners is thereby cut off so soon that the escape
therefrom in such volume as to be an element of danger is rendered impossible.
In the use of the form of the invention in which the supply is cut off from the
main burners only, the escape from the pilot burners is ordinarily so small in
amount that no injurious result can reasonably be apprehended on its account.
It may be preferred, in some cases, that the thermostat should form one outlet
or terminal of the coil while it still is in position to be acted on directly by the
heat from the burners. Such a modification would require no actual change
in the construction; for example, in Figure 1, the portion of the coil extending
below the thermostat may be omitted, or the thermostat may be placed lower
down or at the bottom of the coil. The outlet would then be directly from the
thermostat.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is;-
1. In a water heater, the combination, of a water heating coil, a heater for
heating the same, and a thermostat controlling means in the circuit of the coil
between the inlet and the outlet of that portion of the coil which is subjected to
the action of the heater, substantially as set forth.
2. The combination, in a coil water heater, of a burner, and a thermal regulat-
ing device for controlling the burner, which is located in a section of the coil
exposed to the direct action of the heat supplied by the burner, substantially as
set forth.
3. The combination, in a water heater, of a heating coil enclosed in a casing,
a burner for supplying heat to the coil, and a thermal regulating device for
controlling the burner, and which is located in a portion of the coil exposed to
the direct action of the ignited gases, or flame, from the burner, substantially as
set forth.
:
4. In a water beater, the combination of a burner, a water receptacle arranged
in the combustion chamber of said burner, a thermostat for operating the valve

page_text: main burners and the pilot burners,. 5, may be automatically cut off, upon the
extinguishment of the flame at the pilot burner, thereby obviating the liability
to accident from the continued escape of gas at the burners which would other-
wise take place.
'
To this end, I provide a supplemental thermostat consisting of a rod, 40, of
metal possessing a comparatively high coefficient of expansion, one end of which
is fixed, and the other connected to a tripping mechanism for effecting the
closure of either the main supply valve, 7, or a supplemental and independent
cut off valve, 51, according as the apparatus is designed to shut off the supply
to the main burners only, or to both the main burners and the pilot burner.
In the construction shown in Figures 1, 2, and 3, by which the first of these
functions is accomplished, one end of the supplemental thermostat, 40, is rigidly
connected to a bracket, 41, which is preferably, as shown, secured to the end
of the outer tube, 12, of the main thermostat, opposite to that from which the
rod, 14, projects. The opposite end of the supplemental thermostat, 40, is
pivotally connected to one end of the tripping lever, 42, which is pivoted between
its ends, to a bracket, or support, 43. The lever, 16, does not abut directly
against a bearing on the supply valve stem, 18, its connection therewith being
effected by means of a lever, 44, which is pivoted by a pin, 45, to the free end
of the lever, 16, and bears at one end against a nut, 17, which is adjustable on
the supply valve stem, 18. The opposite end of the lever, 44, abuts against an
arm, 46, on a trigger shaft, 47, journalled on the lever, 16, a short distance from
the pivot pin, 16b, thereon. The shaft, 47, carries an arm, or trigger, 48, which
engages a notch, or recess, in the tripping lever, 42, adjacent to the end thereof
opposite that to which the supplemental thermostat is connected.
It will be seen that the members of the lever system and the supply valve
stem are normally maintained in the relation shown in the drawings, by the
opposite pressures of the thermostat rod, 14, and the closing spring, 19, and that
so long as the trigger, 48, is maintained in engagement with the tripping lever, 42,
the levers, 16, and 44, will move coincidently in either direction, and act in
substantially the same manuer, and with practically the same effect, as if rigidly
connected. When, however, the trigger is released from the notch, or recess,
of the tripping lever, the resistance which previously existed to the action of the
closing spring, 19, is removed, and said spring thereupon seats the gas supply
valve, 7, in the valve casing 20 and cuts off the supply of gas to the main
burners, 4. The lever, 44, is swung upon its pivot, 45, by the movement of the
valve stem, 18, in the closing. of the valve, and in turn swings the trigger
shaft, 47, sufficiently to clear the arm, 46. The release of the trigger, 48, from
its normal engagement with the tripping lever, 42, is effected by the contraction
of the supplemental thermostat, 40, which is necessarily resultant upon the
extinguishment of the flame at the pilot burner, 5, and the parts cannot be
restored to their normal operative positions until the pilot burner is lighted, and
the supplemental thermostat expanded sufficiently to permit the trigger to be
re-engaged with the tripping lever.
It will be obvious that various modifications in the structure of the inter-
mediate mechanism through which the supplemental thermostat effects the
closure of the supply valve, may be made by mechanics skilled in the art to
which my invention relates, without departure from the essential features or
operative principle, and I do not, therefore, limit myself to the specific tripping
mechanism which is herein described and shown.
Figure 4 illustrates a form of my invention in which the supply to both the
main burners and the pilot burner is automatically cut off upon the extinguish-
ment of the flame at the pilot burner, the essential elementa being, as in the
instance first described, a supplemental thermostat, and a tripping mechanism
through which the thermostat effects the closure of a valve controlling the supply
to the burners. The gas service pipe, 6, is, in this instance, lead into the casing,
or chest, 50, of an independent or supplemental cut off valve, 51, which controls