Improvements in Water Heaters.
Year: 1890

page_text: Date of Application, 30th Dec., 1890-Accepted, 28th Mar., 1891
COMPLETE SPECIFICATION.
Improvements in Water Heaters.
I, EDWIN RUUD, of No. 128, Centre Avenue, Pittsburgh, in the County of
Allegheny, State of Pennsylvania, and United States of America, 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 improvements in water heaters for domestic or other
purposes, and its object is to provide an apparatus whereby the flow of gas to a
heating burner may be automatically regulated to effect either an increase or a
decrease of combustion of gas in accordance with decrease or increase in the
temperature of the water which is to be heated. The improvement claimed consists
in certain novel combinations of devices hereinafter fully set forth.
In the accompanying drawings:
Figure 1 is a vertical central section through a water heater embodying my
invention;
Fig. 2, a plan or top view, with the cap or cover removed;
Fig. 3, a horizontal section, at the line, a, of Fig. 1 ; and,
Fig. 4, a section illustrating a modification of the regulating apparatus.
In the practice of my invention I provide a cylindrical shell 1, having a series
of tubes or flues 2, the ends of said tubes being expanded into the heads 3, 3", in
the ordinary manner. The shell is supported at a distance from the floor in
any suitable manner, but preferably by extending the shell below the lower
head 3", as shown in Fig. 1, thereby forming an enclosed box or case for the
burner 4. This box or case is provided with a door 5 so as to permit access to
the burner, said door having a sheet of mica inserted therein for inspection of the
burner. The mixer 4" is preferably arranged outside of the box or case, and is
connected by a pipe 6 to the valve case 7, to which the gas supply pipe 8 is also
connected. The flow of gas to the burner is regulated by a valve 9, the stem
thereof passing up through a stuffing box 10, and is connected to one end of a
lever 11, by means of nuts 12, screwing onto the stene above and below the end
of the lever. This lever is pivoted to an arm of a bracket 13 secured to the shell
of the heater, and to the inner end of said lever, is attached one end of the
expansion rod or tube 14, which is preferably formed of a material having a
greater coefficient of expansion than that of the material of which the heater is
formed. This rod passes down through a stuffing box 15 arranged on the upper
head 3 of the heater, and through an isolating pipe 16 arranged within the heater.
The lower end of the rod 14 is firmly attached by nuts or other suitable means
to the lower head 3 of the heater, so that the aggregate traverse of the rod due
to variations of temperature will be at its upper free end. The water supply
pipe 18 is connected to the isolating pipe near its upper end, which is closed by a
cap 19, while its lower end is open, thereby causing the water passing into the
shell to traverse said tube before entering the water space of the shell.
The burner 4 which is preferably circular in contour, is provided on its upper
face with a valve disc or plate 20, centrally pivoted, so as to be free to rotate as
hereinafter described, and having perforations adapted, when properly shifted, to
register with the perforations in the burner. This valve plate is connected by a
rod 21, to one arm of a bell crank lever 22, the other arm thereof being connected
by a rod 23 to the lever 11, so that the movement of the lever 11 in opening or
closing the valve 9, will so shift the valve plate as to uncover or cover the
perforations in the burner 4. A small burner 24 is arranged over the main
burner, and is connected, by a pipe 25, to the gas supply pipe 8, at a point outside

page_text: of the valve 9, so as to provide an igniting flame for the main burner.
In order
to provide air for the igniting flame, the pipe 25 is surrounded by a short tube, one
end of which is located outside of the case enclosing the main burner, while the
other end is closely adjacent to the burner 24.
The heater is provided, as is customary, with an outlet pipe 26 and a drainage
cock 27.
In order to avoid the use of a stuffing box where the rod 14 passes through the
head 3, an internally and externally threaded nut 28 is screwed into the head 3,
and the tubular rod 14, formed of brass or other metal having a high coefficient of
expansion, is screwed into the nut, as shown in Fig. 4, thereby securing the upper
end of the tube to the head 3 of the heater. This tube extends down into the
isolating pipe 16, and within said tube 14 is arranged a rod 29, which is firmly
attached at its lower end to the free lower end of the tubular rod 14, by means of
a nut 30. The upper end of the rod 29, which is made of iron or some material
having a smaller coefficient of expansion than the tubular rod 14, extends up above
the head 3, and engages the lever 11. It will be observed that in the construction
shown in Fig. 1, the expansion of the rod 14 causes an upward movement of its
upper end, whereas, in the construction shown in Fig. 4, the expansion of said rod
will effect a downward movement of its lower end, thereby pulling down the rod 29.
Hence, in order to employ the same construction of valve as shown in Fig. 1, the
lever 11 in Fig. 4 is pivoted to an arm 31, attached in any suitable manner to the
head 3, and so arranged that the rod 29 engages the lever at a point between its
pivot and its connection with the valve stem.
In using my heater the connections of the stem of the valve 9, and of the plate
valve 20, with the lever 11, are so adjusted that when the water in the heater is
at the normal temperature of the supply, the valve 9 will be opened, and the
perforations in the plate valve 20 register with those in the burner. Said con-
nections are also so adjusted that the expansion of the rod 14, when the water has
been heated to a certain predetermined degree, will close the valve 9, and also
shift the plate valve 20, so as to cover the perforations in the burner, thereby
preventing a flow of cold air through the mixer and burner and thence through
the flues 2. If water be withdrawn from the heater, cold water will flow in
through the supply pipe, and passing down through the isolating pipe, will cool
the rod 14. The consequent contraction of said rod will open the valve 9 and
shift the plate valve 20, thereby permitting the gas to escape through the burner
and be ignited by the constant flame of the burner 24.
It will be observed that, by the employment of the isolating pipe, a more
prompt action of the valves 9 and 20 is produced than would be possible, if it
were necessary to wait for an equalization of the temperature of the entire
body of water in the heater. Although it is preferred to employ the isolating
pipe, the operativeness of my device is in no way dependent thereon, and it may
be omitted.
In order to prevent any injury to the mechanism, in case of an excessive
movement of the expansion rod 14, a spring cushion 31 is interposed between the
end of the lever 11 and the lower nut 12.
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. The combination of a heater, a gas burner arranged below the heater, a
perforated disc arranged over the burner, a valve for controlling the flow of gas
to the burner, and mechanism operated by changes of temperature of the water
within the heater for shifting said disc and valve, substantially as set forth.
2. The combination of a heater, a gas burner arranged below the heater, a
valve for controlling the flow of gas to the burner, an expansion rod extending
into the heater and connected at its outer end to said valve, and a pipe

page_text: surrounding the expansion rod and connected with the supply pipe, substantially as
set forth.
3. The combination of a heater, a gas burner arranged below the heater, a valve
for controlling the flow of gas to the burner, a tubular expansion rod arranged
within the heater and having its upper end attached to the head of the heater, a
rod 29 having a smaller coefficient of expansion than the tubular rod and arranged
within the same, the lower end of the enclosed rod being attached to the free end
of the tubular rod, and a lever connected to the valve stem and engaging the
projecting end of the rod 29, substantially as set forth.
Signed at Pittsburgh Pa UŠA this 96th day of November 1900.
In the presence of :
J. SNOWDEN BELL.
DARWIN S. WOLCOTT.
EDWIN RUUD.