Improvements in Steam Generators, and in the Furnaces Used in connection therewith.
Year: 1896

page_text: Date of Application, 28th Apr., 1896-Accepted, 4th July, 1896
COMPLETE SPECIFICATION.
Improvements in Steam Generators, and in the Furnaces Used in
connection therewith.
I, DAVID MOULTON THOMPSON, of 29 Wilcox Street, in the City of
Providence, County of Providence, State of Rhode Island, United States of
America, Engineer, do hereby declare the nature of my invention, and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
This invention has reference to an improvement in vertical tubular steam-
generators in which a vertical cylindrical shell provided with tubes is supported
above a circular furnace, so that the products of combustion pass vertically through
the tubes, and is particularly well adapted for the class of vertical tubular steam-
generators in which a water leg extends from the cylindrical shell centrally
downward through the center of the furnace.
Vertical tubular steam-generators require to be supported above the furnace,
and in the most common form they are supported by extending the shell down
below the furnace and forming this portion of the shell into a water-surrounded
fire-box; the water space forming the fire-box, being part of the boiler, is
subjected to the full steam pressure and the pressure incident to the height of the
column of water in the whole boiler, the inner shell cannot withstand this pressure
and requires to be stayed by connecting it to the outer shell by stay-bolts placed
at frequent intervals-the fire-box, so constructed, contracts the area of the grate,
is costly, and the weakest part of this class of steam-generators.
This class of steam-generators is also supported frequently on brick walls which
enclose the furnace,-these are objectionable on account of continual expansion
and contraction of the walls and the great loss of radiated heat from the same.
While for the generation of steam for power exerted through a modern compound
steam-engine the vertical boiler has many advantages, it is desirable to materially
increase the grate area to facilitate the perfect combustion of even a low quality
of fuel and adapt this class of boilers for the use of any kind of water, even the
inferior, water containing lime and other impurities.
The object of this invention is an improved construction of vertical tubular
steam-generators and to provide a furnace for the same which prevents the loss of
the heat by utilizing the same, secures a larger grate. area for.the furnace, a refractory
surface around the fire to facilitate the combustion. of the fuel.. before the gases
enter the tubes, and a firm reliable support for the vertical tubular boiler.
Another object of the invention is to secure more perfect combustion of the fuel
and better control of the fire in a vertical tubular steam-generator.
Figure 1 is a vertical sectional view of the lower part of a vertical tubular
boiler provided with my improved furnace.
Figure 2 is a vertical sectional view of the upper part of the steam-generator.
Figure 3 is a horizontal sectional view of the furnace on the line A-A,
Figure 1, and
Figure 4 is a horizontal sectional view of one-half of the vertical tubular steam-
generator on the line B-B in Figure 1.
Similar numerals of reference designate corresponding parts throughout.
In the drawings 1 iudicates the cylindrical shell of. the steam-generator, 2 the
covering composed of some slow couductor of heat, 3 the lower tube-sheet, 4-4 the

page_text: tubes, 6 a truncated conical cylinder which connects the lower tube-sheet 3 with
the central tube 7 the lower end of which is secured to the flanged-socket 8 which
is in its turn secured to the mud-drum 9 with the lower end of which the blow-off-
pipe 10 is connected. Within the central tube 7 is placed the tube 11 provided at
its upper end with the funnel-shaped conical tube 12. By this arrangement the
rentral portion of the tube-sheet is supported and rapid circulation of the water
in the central tube 7 is secured,-the water in the annular space between the
tube 7 and the tube 11 is subjected to the heat of the furnace, the heated water
rises in this annular space and is replaced by the water descending through the
interior tube 11,-impurities held in suspension by the water are precipitated into
the mud-drum 9 and are readily blown out by means of the blow-off pipe 10.
To facilitate the circulation of the water, the internal inspection of the generator
and the thorough cleaning of the same, the circular well 13 is formed and the
ends of the generator are stayed by means of the rods 14, one pair of these rods is
made into a ladder by securing rungs to them, as is shown in Figures 1 and 2, and
access to this central well is secured through the manhole 15 placed in the end of
the steam-dome 16 from which the steam-pipe 17 carries the steam to the engine.
To facilitate the thorough cleaning of the interior of the generator, the tubes 4-4
are placed in radial lines, as is shown in Figure 4, so that every part of the surface
of the tubes can be reached from the central well 13.
The main suppport of the vertical tubular generator consists of a circular
cellular casing made up of sections 18 curved so as to form a dome-shaped base
for the generator, the sections 18 are divided by the vertical ribs 19 into vertical
cells and these are connected at the bottom by the openings 20 and at the top by
the openings 21. In the, sections 18 of the casing the firing openings 22 are formed
and these are surrounded by the cellular casings 23 connected by openings with
the cellular spaces in the sections 18. Water is supplied to the cellular spaces in
the casing through the pipe 24 from which the branch pipes 25 extend to the lower
part of each section as shown in Figure 1,-the upper ends of the sections are
connected by the pipes 26 with a pump by which the heated water is supplied to
the vertical tubular generator.
The water may be supplied to the cellular casing by means of a pump, or it may
be supplied from a tank, located above the casing, provided with an automatic
supply-cock, and the heated water from the casing may also be delivered into a
tank placed on the same level with the supply-tank, so that in the normal condition
the connections between the supply and the delivery tanks are always open and
the casing is never subjected to a higher pressure than that incident to the static
pressure of the column of water.
The interior of the casing is lined with the fire-brick resting on a circular rim
extending inward from the casing and strengthened by the vertical ribs 28 which
also form the support for the outer circular grate-bearing-rim 29 on which the
outer grate-bearers 30 are supported by the balls 31. The grates 32 rest on these
outer bearers 30 and on the inner bearing-ring 301 which is also supported on
similar ball-bearings.
:
Economy in fuel and the efficiency of a steam-generator depend largely on the
skill of the fireman to keep the grates clear and supply the fuel evenly over the
whole grate in the shortest time, for every moment the fire-door is open large
quantities of air rush into the generator and reduce the temperature.
In vertical tubular boilers it is difficult to clean the grate and evenly distribute
the fuel unless at least three firing doors are provided and these are successively
opened. When a number of such boilers are used in one building a large space
has to be left free around these boilers so as to handle the slicing bar and the
shovel, this is, in many cases, impractical, and to overcome this difficulty I
construct the grate surface so that it slowly revolves and all parts can be reached
from one firing opening. With such a construction any required number of
vertical generators can be set close together side by side or placed close together
in a group, and to this end I provide the circular bearing bar 30 with gear-teeth

page_text: and connect the pinion 33 which is secured to the vertical shaft 34 with the same,-
the vertical shaft 34 is connected, by means of the pair of beveled-gears 35, with
the shaft 36 to which motion is imparted from some prime motor. The gearing is,
for the sake of clearness, shown on the inner side of the cylindrical bearer 30,
but may in practice be placed on the outer periphery and the pinion 33 and shaft 34
be placed into a space made for the same in the cellular casing 18 provided with
a door.
The vertical tubular cylinder is firmly supported on the circular arched casing
by brackets, or a flanged ring riveted near the lower end to the cylindrical shell,
as is shown in Figure 1, giving to the same, by reason of the enlarged base, a very
firm and substantial support. The dome-shaped inwardly-curved furnace lined
with refractory material secures a large grate area and a large combustion chamber
in which the gaseous products of combustion are maintained at a high temperature
in a space vastly larger than the combined area of the tubes therefor for a sufficient
length of time to secure perfect combustion of the gases before they pass into the
tubes where they give up their heat to the water in the generator and after passing
through the portion of the tubes above the water line, where they dry and
somewhat superheat the steam, they pass into the uptake 37 and on to the
chimney.
The fire-brick lining 27 of the furnace, while it maintains the high temperature
of the furnace and is but a slow conductor of heat, conducts all the heat, ordinarily
lost, into the water in the cellular casing, thereby the loss by radiation is reduced
to the lowest point, the waste heat is utilized and the casing protected against
injury by heat.
The feed-water for the generator is taken from the upper part of the casing or
the delivery tank and is supplied through the pipe to the discharge-pipe 39° the
upper open end of which is protected by the hood 40.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
Claim 1. In a vertical tubular steam-generator, the combination with the
cylindrical shell, the end tube sheets, the tubes placed on radial lines, and the
central well, of the conical cylinder 6, the tube 7, the mud-drum 9 provided with
the blow-off-pipe 10, the circulating tube 11 provided with the funnel-shaped
end 12, and the feed-water supply-pipes 38 and 39 having the outlet protected by
the cap 40, as described.
2. The combination with a vertical tubular steam-generator, of a cellular casing,
disconnected from the steam-generator and provided with water-supply inlets and
hot-water outlets, constructed to form the support of the generator and enclosure
for the furnace, as described.
3. The base for a vertical tubular steam-generator, consisting in a number of
cellular segmental sections connected at the top and bottom to form a continuous
water space, lined on the inner surface with a refractory material, as described.
4. In a steam-generator, in combination, a vertical cylindrical shell, an annular
group of tubes surrounding a central open well within the cylindrical shell, a steam
dome extending above the upper tube sheet and provided with a steam outlet and
a manhole, a central column connected with the lower tube sheet and extending
below the grate, a cellular casing constructed to support the cylindrical shell and
enclose the furnace, a circular grate and mechanism for rotating the same, a feed-
water pipe connected with the cellular casing, a hot-water outlet for the cellular
casing, a feed-water pipe connected with the central column, and connections,
between the hot-water outlet from the cellular casing and the feed-water pipe
supplying the central column, whereby the feed-water supplied to the cellular
casing is heated and delivered to the steam-generator, as described.
5. The combination with a vertical tubular steam-generator, a central cylindrical
extension from the lower tube sheet to a mud-drum below the grate surface, of an

page_text: annular fire-box provided with an opening for supplying fuel, the annular grate 32,
the ring-shaped bearing-bars 30 and 301 supported on bearing-balls, and a gear and
pinion mechanism for rotating, the grate, as described.
6. In a base forming the furnace and support for a vertical steam-generator, the
combination with the sections 18 vertically divided by the ribs 19 into cellular
water spaces, the openings 20 and 21, the brackets-28, the supporting ring 29, the
channeled bearing-bars 30, the balls 31, the grates 32, and the fire-brick lining 27;
constructed to heat the feed-water before it is supplied to the steam-generator, as
described.
Deted the 11th dow of Mouch A D 1896
DAVID MOULTON THOMPSON.
Haseltine, Lake & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.