Improvements in Apparatus for Automatically Regulating the Supply of Air to the Furnaces of Hot Water Boilers.
Year: 1889

page_text: Date of Application, 10th Sept., 1889-Accepted, 7th Dec., 1889
UUMI LEIE DI MUIFICATION.
Improvements in Apparatus for Automatically Regulating the
Supply of Air to the Furnaces of Hot Water Boilers.
I, WILLIAM PENN Powers, of La Crosse, in the State of Wisconsin, United
States of America, Mechanical 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 provision for automatically controlling the damper of a
furnace by which heat is supplied to boilers that are used for hot water heating. It
becomes important in connection with water heated for this purpose, that it should
be so controlled that the temperature may not rise sufficiently for its conversion into
steain, and therefore no means can be derived from the water directly for the purpose
of automatically operating a damper. To the end that steam may be obtained from
the temperature of the water, I supply a supplemental boiler or steam generator
containing water, that I surround with the water used for the heating purposes under
conditions that will permit generation of steam at a temperature below that necessary
for generating steam in the main boiler. This result is obtainable by the fact, that
the water in the main boiler which is supplied from a source at a considerable distance
above, is under a very considerable pressure. My supplemental boiler I so arrange
that the pressure upon the fluid therein is not above atmospheric, and will thus boil at
about 212 degrees Fahrenheit.
For the purpose of a definite description of my invention, reference is had to the
accompanying drawings in which,
Figure 1 is an elevation, connecting pipes being broken away.
Figure 2 is a detail in vertical section through the diaphragm and generator.
While I
For my present illustration, a boiler A is shown, in which by dotted lines longitu-
dinally, I have indicated flues, though these do not enter in as a factor in my present
invention. Boiler A is supported upon a furnace B, which in turn is supported upon
a suitable sub-structure C, as a provision for ash-pan, draught, etc. To this portion C
I have hinged a damper D. Above the boiler is shown a chimney or flue E, for
carrying off the products of combustion and furnishing the necessary draught. In
boiler A is shown inserted, a pipe F connecting above with expansion tank G, located
above the boiler whereby the water of the latter is held under greater than atmos-
pheric pressure, due to the weight of the column of water in the pipe F.
have not shown any pipes for distributing the water throughout a building, this
provision may, of course, be made in any suitable manner, by connecting such
distributing pipes with the studs y, y projecting from the boiler, with tank G,
necessarily at an elevation above such pipes. The supplemental boiler by which the
steam is to be generated in the present illustration consists of a closed vessel H
secured within an enlargement H' of a pipe I leading from the boiler A to a radiator.
This supplemental boiler or generator, I supply with water which has a lower boiling
point than the water in the heating boiler, due to the fact that the water in said
supplemental boiler is not under pressure, when the temperature of the water in the
heating boiler rises above the boiling point of the fluid in supplemental boiler H,
steam is generated therein. The steam thus generated may be utilized to close the
damper in any convenient manner, but as here shown, a pipe I' leads from H and is
turned up where, at its terminal, is supported a device for utilizing steam, whereby
the damper may be operated. This device embraces a shell, shown in section in
Figure 2, composed of upper and lower plates a and a¹, that are provided with
peripheral flanges which form the contact surface of one plate with another.

page_text: Within this shell is placed a diaphragm d preferably composed of a sheet of rubber,
that is stretched within the shell and its margins held between the flanges of the
plates a and a¹, the latter being so bolted together as to secure said diaphragm and
also form a tight joint. The diaphragm thus acts as a flexible partition centrally of
the shell. A steam tight chamber is thus formed beneath the diaphragm, but, due to
the flexibility of the diaphragm under steam pressure, its dimensions are enlarged and
the diaphragm elevated. Upon the upper surface of the diaphragm rests a plate e, to
which is attached a stem e¹. An extension 6 from plate a serves as a fulcrum for a
lever J, to the outer end of which is connected a chain J¹, that connects with a
damper D. Stem e¹ is also attached to the other arm of lever J, and at the inner end
of lever J is a weight j that serves to normally depress that end of the lever and force
stem e downwardly. It is designed that the action of the steam generated in H and
conducted through pipe I' shall, when sufficient, operate to raise diaphragm d, thereby
raising lever J and thus closing the damper. When, by reason of the damper being
closed, the temperature of the water in the main boiler becomes sufficiently lowered
to stop the generation of steam in boiler H, and permit condensation in pipe I',
diaphragm d is allowed to subside and the weight, by depressing lever J, again
opens the damper. Though water be used in the supplemental boiler H, it is evident
that the steam will be generated therein sufficient for the purpose designed before the
water in the main boiler has reached a temperature sufficient to generate steam,
owing to the pressure of the water in the pipe above, in addition to the atmospheric
pressure which necessitates a temperature above 212 degrees, or the ordinary boiling
point, to convert the water in the heating boiler into steam. The form of supple-
mental boiler, or construction of parts may, of course, be varied, and the submerged
supplemental boiler is not necessarily located in the pipes of the circulation, but may
be placed in the boiler and a piston may be used instead of the diaphragm. I do
not therefore, design to limit my invention to any particular form of construction, its
real scope embracing the supplemental boiler submerged in the hot water of the
heating system and containing water boiling at a lower temperature than that in the
heating boiler, owing to the difference in pressure.
In constructing the diaphragm, I make it relatively very large as compared with
the utmost possible displacement obtainable by molecular expansion under the
influence of the heat applied, the intention being to accomplish the work by vaporiza-
tion only and at a very low pressure with large increase of volume, and for the reason
that by vaporization only can positive action be obtained at the right time.
In hot water heating apparatus, as heretofore constructed, it has not been practicable
to carry a temperature of more than 185 degrees or 190 degrees, because in the
ordinary fluctuations the boiling point might be passed, which would result in
discharging the water of the boiler into the expansion tank. Hence all radiators
have been proportioned in size to this temperature of 185 degrees or 190 degrees,
and the size, unsightliness and expense of these radiators have deterred many from
adopting this system of heating. Now by means of my improvements, I am enabled
to carry constantly a uniform temperature of 215 degrees or 220 degrees with the
same degree of exactness that a low pressure steam heating system maintains unvary-
ing heat, and at very nearly as high a temperature, thereby effecting a great saving
in the size and cost of radiators: as with my improvement, an increase of at least
15% is secured in the heat of the system, thereby enabling 15% less radiation to be
used, and more uniform results secured.
In those cases where volatile liquids have been used it has been necessary to
employ metallic diaphragms instead of rubber, from the fact that all volatile liquids
are active solvents of rubber. In practice it has been found impossible to provide a
metallic diaphragm that is sufficiently sensitive and at the same time durable, and
so none of these devices have come into use, though they have been much needed.
By my invention, I overcome this objection and am able to use a rubber diaphragm,
making a sensitive and sure device, operating at just the right time to secure the
• utmost heat practicable from a hot water apparatus.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I wish it understood
that I claim ;-
First. The combination of a main boiler, a pipe communicating therewith and
extending above it for containing a column of water by means of which the water in
the boiler is held under greater than atmospheric pressure, a supplemental boiler or
steam generator, so located as to be heated by the water of the boiler, containing
water under a pressure lower than that in the main boiler, a pressure chamber
containing a diaphragm, and communicating with the supplemental boiler, and a
suitable heat controlling device, the body of water in the supplemental boiler being in
such quantity that the increase in volume when raised from the normal to the boiling
point, will be less than the displacement of the diaphragm when raised to operate the
heat controlling device.
Second. As an attachment for water circulating systems, a supplemental boiler, a
pressure chamber communicating therewith containing a diaphragm, and a body of
water in the supplemental boiler, the quantity of water being such that the increase
in volume when raised from its normal temperature to the boiling point, will be less
than the displacement of the diaphragm when raised to operate the heat controlling
device.
D: 101
bo 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.