Improvements in Radial Tube or Porcupine Steam Boilers.
Year: 1893

page_text: of Application, 16th Feb., 1893-Accepted, 25th Mar., 1893
COMPLETE SPECIFICATION.
Improvements in Radial Tube or Porcupine Steam Boilers.
I, EDWARD SELDEN TOWNSEND KENNEDY of No. 716 East 13th Street, in
the City and State of New York, 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 :-
This invention relates to a radial-tube or "porcupine" steam boiler, which
embraces as main features of construction a water cylinder or stand-pipe provided
with radial water and steam tubes, an enclosing shell or jacket, provided at the
bottom with a deflecting furnace and above with segmental or annular deflecting
plates at different heights above the fire box,-a steam drying and superheating
apparatus at the top of the stand-pipe,-wrought metal boiler tubes having
hemispherical ends closed by the metal welded upon itself,-details of construction
in the stand-pipe to provide for uniformly distributing the flame and products of
combustion through the radial tubes and around the entire circumference of the
stand-pipe, details of construction for supporting the grate and other details of
construction for making the boiler more effective and durable.
The radial tubes above the water liue in the stand-pipe serve for drying steam;
and in order to secure better results in drying the steam, I arrange at the top of
the stand-pipe a steam drying and superheating apparatus comprising means for
subdividing and distributing the whole volume of steam generated, in numerous
small streams or currents into a drying chamber, and also into superheating tubes;
and a separate discharge chamber closed at the bottom and opening at the top into.
the main steam take-off pipe. A series of open ended radial distributing pipes are
preferably connected with the distributing chamber and extended into a series of.
larger radial tubes, which project into the hot air chamber of the boiler shell, so
that the whole volume of steam is compelled to pass out through one series of tubes
and back through the other series before reaching the delivery chamber or take-off
pipe, whereby very extensive steam drying and superheating surface is utilized and
dry, high pressure steam is delivered.
The shell of the boiler may be constructed of brick or metal, and when of metal.
the walls may be double having the space between filled with non-conducting
material or with water.
An important part of my invention consists in the combination with the boiler
and its shell or jacket of horizontal, annular or segmental flame deflectors, prefer-
ably connected to the shell or jacket and projecting into the combustion chamber
in positions for protecting the exposed ends of the radial tubes from too great heat
and at the same time deflecting the heated products of combustion toward the
boiler cylinder or stand-pipe.
I preferably construct the stand-pipe of short cylindrical sections and rivet
these sections together, in such manner that their vertical seams shall be in different.
vertical planes, that is, turned one from the other from one-quarter to one-third or
one-half of the circumference of the stand-pipe, so that only short flue spaces are.
formed at the vertical seams and therefore the flame and hot products of combustion.
better distributed through and between the radial tubes around the entire
circumference of the stand-pipe. I also weld together the longitudinal edges of
the metal plates forming the stand-pipe, so that there shall be no riveted seams to
interfere with the regular setting of the radial tubes.
Another feature of my boiler is the corrugated section of stand-pipe which
nasses through the fire box.

page_text: I will now describe in detail the construction of my boiler by reference to the
accompanying drawings, in which,―
✓
Figure 1 represents an elevation with part of the shell and stand-pipe in vertical
Bection ;
Figure 2 represents a plan view and horizontal section at different horizontal
planes;.
Figure 3 represents a vertical section showing the corrugated lower end of the
stand-pipe;
Figure 4 represents a vertical section on enlarged scale of my steam drying
apparatus;
Figure 5 represents a horizontal section thereof on the irregular line x-x,
Figure 4.
Figure 6 represents a vertical section of the steam drying apparatus arranged in
duplicate;
Figure 7 represents a sectional view of a modified form of a steam drying
apparatus ;
Figure 8 represents a vertical section of another modified form of steam drying
apparatus ;
Figure 9 is a sectional plan at different elevations.
Referring now to Figures 1 and 2, the furnace and shell A, of the boiler are
built of brick and lined a sufficient height with fire brick mounted upon a
foundation W. The shell is provided with numerous sight openings and doors u,
and is surmounted by a hood, T, and smoke-stack, V, having a valve v. A fire-
chamber, C, ash-pit, D, and grate E, are constructed in the lower part of the
furnace shell, and the fire-chamber is provided near its top with brick deflectors, c,
as shown. Iron deflecting plates, c', project inward at different heights from the
walls above.
The brick deflector, c, is preferably used at the top of the fire-box, C, and it is
built of corbeled brick work extending from the brick boiler shell, A, around its
entire circumference, as shown in Figures 1 and 2, though in Figure it is partly
broken away for showing the construction of the furnace wall below. The deflect-
ing plates, c', are preferably made annular so as to protect the ends of the radial
tubes all around the boiler and uniformly deflect the flame and hot products of
combustion inward toward the stand-pipe.
These plates, are preferably inserted at their outer edges in the brick work by
which they are held in place, but they may be suspended from the radial tubes by
wires or other means.
The positions in which the deflectors shall be placed are determined by various.
conditions. If the grate surface extends but partially around the boiler cylinder,
a deflector should be placed above the fire to direct the flame to the opposite side
of the boiler. The upward draft is in some instances stronger at one point than at
another. A deflector properly placed will regulate such draft.
At a suitable height above the floor of the ash-pit a ledge, d, is formed in the
brick furnace-wall and covered by a cast-iron plate, and at the same height the
stand-pipe has riveted to it the wrought-iron brackets, h, which support the wrought-
iron ring, H. This ring is sufficiently large to set out from the stand-pipe and
leave a clear annular space between the two, as shown in the drawings, for
circulation of air, whereby burning and injury of the stand-pipe by excessive heat
at this point is prevented. The ledge and ring support the outer and inner
ends, e, e, of grate-bars, E. The grate surface is circular in form, and in_large
boilers extends entirely around the stand-pipe. The grate-bars or sections, E, are
preferably made with angular openings or slots, as shown in some of the sections in
Figure 2.
Air inlet openings, 1, extend from the outside of the furnace wall to the annular
air space, l, in the brick work surrounding the fire chamber, C, and ports, ",
connect such annular air space at the bottom with fire chamber, C, whereby air

page_text: may be heated for supporting combustion. The usual fire and ash-doors, a, a¹, are
provided.
The stand-pipe, B, is composed of suitable sections, which are joined together at
their ends by circular rows of rivets. At the bottom the stand-pipe is provided
with a flanged and dished head, I, (Figure 3) riveted on the cylindrical portion, the
walls of which extend down and rest upon the iron foundation plate, i, placed upon
the supplementary brick foundation, n.
The stand-pipe is provided round its entire circumference above the fire box with
the radial wrought-metal tubes, b, extending out nearly to the furnace wall or shell,
as shown in Figures 1 and 2. The tubes are inserted at their inner open ends in
the holes of the stand-pipe and are then expanded by means of a suitable tool, so as
to securely hold them in place and form a tight joint between them and the metal
stand-pipe. I preferably use tubes, composed of wrought-metal and having the metal
at their outer ends closed and welded upon itself, so as to form a seamless hemi-
spherical end of thickened metal possessing great strength and durability.
The stand-pipe is closed at the top by means of a flanged and dished head, I',
and in the upper end is fitted my special arrangement of steam drying and super-
heating apparatus. The radial tubes, b, above the water line serve for drying steam
and in order to compel the steam to better circulate through them, I provide a
special arrangement of chambers and radial pipes as described below.
Referring now more particularly to Figures 4 and 5; I construct a central steam
distributing chamber, R, closed at its upper end, and connect with such chamber, a
series of open ended tubes or pipes, r, extending radially, in different planes, into
the surrounding discharge chamber, R', and its radial tubes, 6. In constructing
these chambers, I bolt or otherwise secure to the stand-pipe a sufficient distance
below its top an angle-ring, 9, and bolt thereto the annular bottom plate, Q, formed
of the segmental plates united by flanges, and to plate, Q, which is provided with
a central opening, I bolt the interior angle-ring, q', to which is connected the
central distributing chamber, R, open at its lower end. The upper end of
chamber, R, is closed by a plate or disk, r', which is secured by long bolts and their
ferrules or sleeves, p, which also serve to hold in place the upper annular plate,
The long bolts and sleeves, p', serve to set the plates, r¹ and a sufficient distance
apart to form a steam passage to the discharge pipe S, which is fitted in plate 1
and in the head I. The bottom plate, Q, forms a deflector by means of which
steam rising in the stand-pipe is driven into the distributing chamber R. A series
of open ended distributing tubes, r, arranged in different horizontal planes, are
connected to the distributing chamber R and extend radially through the annular
discharge chamber R', and thence out into the radial superheating tubes, b¹,
connecting with chamber R', as shown.
The bottom plate, Q, is provided with an opening in which is fitted the end of
drip-pipe, pl, which, in practice, extends down into the water in the stand-pipe for
draining off any water of condensation which may collect in chamber R¹.
Under ordinary circumstances, the radial steam superheating tubes, 61, having
distributing tubes, r, extending into them, as shown in Figure 4, are preferably
used; but, under some conditions, the tubes, 61, may be dispensed with, and in such
cases I may use to advantage the distributing tubes, r, terminating in chamber, R',
near its circumferential wall, as shown in Figure 8. In case of this construction,
the outer ends of a part or all of tubes, r, may be turned downward, as shown,
for discharging condensable matter upon the bottom plate, Q. The steam is
thus freed from condensable matter and is discharged in a dry condition.
drain-pipe, p', conducts away from chamber, R', any water of condensation which
may be deposited and discharges it into the water of the stand-pipe'below.
The
My steam drying apparatus constructed. in the form' shown in Figure 8, máy.
be applied with advantage to the dome of a horizontal tubular or flue boiler.
For the purpose of more thoroughly drying and superheating steam, I. may
construct in duplicate. the distributing chamber Rand discharge chamber, RI,

page_text: 0
,
with their systems of radial tubes, as shown in Figure 6. Ordinarily, however,
this duplication of the apparatus will not be required.
As an additional means for separating condensable vapor from the steam, I
provide an internal deflecting cylinder, O, open at both ends and secured at its
lower end within distributing chamber R, as shown in Figure 6. In this case, I
connect a drip-pipe, o, to the bottom of chamber R, and extend such pipe down
into the water of the stand-pipe.
In the operation of my steam drying and superheating apparatus, the steain
rising in the stand-pipe is caused to flow first into the distributing chamber R, from
which it is distributed in numerous small streams through radial tubes, r, and
discharged into the outer radial superheating tubes, 61, where it is superheated and
flows thence into the annular discharge chamber R', and thence escapes through
the take-off pipe S, to the engine or other place of use. Since the radial. tubes, ',
..extend into the hot air chamber of the boiler shell they will be highly heated and.
since the steam is compressed into the distributing chamber R, it will be forced
under pressure through the distributing tubes, », into the superheating tubes, 4,
where, by contact with the highly heated metal, it is thoroughly and uniformly
superheated. The tubes, 61, being of larger diameter than tubes, r, permit the
steam as it is superheated to freely expaud, so that there is no undue back pressure
into chamber R. The arrangement of the bottom plate, Q, and the central distri-
buting chamber, R, effectively overcome any tendency to priming.
.
An
Figure 7 illustrates a modified form of the steam drying apparatus in which the
diaphragm plate, Q, is dispensed with and the central steam chamber is changed to
a discharge chamber, R2, closed at the bottom and opening at the top directly into
the steam take-off pipe. A series of open ended tubes or pipes, r, are connected
to chamber R², and project radially into the outer radial-steam tubes, b'.
internal deflecting cylinder, O, is secured to the top of chamber, R³, and extends
down near the bottom thereof where it is supported and held in place by the angle-
iron clips or bracket w. A drip-pipe, pl, is fitted to the bottom of chamber, R,
and extends down into the water of the stand-pipe for permitting water which is
separated from the steam to flow back into the stand-pipe. By the construction of
my steam drying apparatus, as shown in Figure 7, the steam rising in the stand-
pipe is compelled to pass in numerous small streams or currents, first out through
the radial tubes, b', where it is superheated and then return through the inner
tubes, r, into the discharge chamber, R', as indicated by the arrows, before escaping
from the boiler through pipe S. The currents of steam returning through the
inner tubes, r, are deflected by the internal cylinder, O, and the whole volume
compelled to pass between the walls of chamber R, and said cylinder, O, so that
any condensable vapor present will be separated and only dry steam will pass up
through the chamber R' to the take-off pipe. Quite satisfactory results are
obtained by this form of apparatus.
The lower end of the stand-pipe below the grate forms a mid-drum, L (Figure 3)
which receives the sediment from the currents of water circulating above, and this
drum is provided with a man hole, provided with a tight fitting plate, k. This man
hole affords access to the stand-pipe for expanding the tubes in their holes and
afterward for inspecting and cleaning the tubes and stand-pipe and removing
deposits from the mud-drum.
A water-feed pipe, w, connects with the stand-pipe, just below the grate, as
shown in Figure 3. A blow-off pipe, y, passes into the stand-pipe below the grate
and is bent downward to near the bottom of the mud-drum. A water-column
pipe, x, connects with the top of the stand-pipe and also with the bottom below
the grate, and is provided at, the junction of its horizontal and vertical portions
with a three-way valve, t, from which leads a discharge pipe, a', into the ash-pit.
Instead of uniting the edges, of: the metal plates which form the sections of the
stand-pipe by riveted seams, I may: weld-such edges together, thus doing away
with the vertical riveted, seams, avoiding, the thickening of metal where such

page_text: seams are usually placed and providing for the regular setting of the radial tubes...
In order to secure a more extended heating surface in this type of boiler, I provide
the lower section of the stand-pipe which passes through the fire chamber with ⠀
corrugations, b, as shown in Figure 3.
This boiler is very economical and effective as a steam generator in any position,
and is specially well adapted for utilizing waste heat from metallurgic and other
furnaces. It may be connected with a furnace for burning bagasse and perfectly
heated by the flame and hot products therefrom and generate high pressure
steam.
Figure 9 illustrates in horizontal section, the brick deflector, c, (generally
termed the deflecting furnace) constructed and arranged eccentric to the stand-
pipe, and the grate-bars, E, extending over only half the diameter of the fire-box
or space within the furnace walls. A bridge wall, j, of proper height is built
across the fire-box at each side of the stand-pipe and at the rear of the grate. A
single firing door, a, is used.
This construction is more particularly adapted to small boilers, wherein if the
grates were placed all around the stand-pipe they would be too short to be useful.
Boilers of this form are advantageously used in rolling mills, forge works and
kindred industrial works where they are arranged to utilize waste heat from the
metallurgic furnaces, and in which cases the neck of the furnace is connected to
one opening in the brick wall of the boiler.
The narrow space formed by this eccentric deflecting furnace at the side of the
boiler at which the waste heat flue enters prevents the heated products from_
ascending in full force, and the wider space at the rear invites the proper proportion
of heated products to that point, resulting in practically giving the entire boiler
the same treatment and protecting it from overheating due to the flame and '
heated products being applied to one side only.
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:
1. The combination with a boiler having a vertical water cylinder with radiating
tubes and the described steam drying and superheating apparatus, of an enclosing
shell, a deflector constructed of corbeled brick work at the top of the fire chamber,
and other deflectors above, arranged to deflect the flame and products of com-
bustion toward the boiler cylinder and protect the end of the radial tubes, sub-
stantially as herein shown and described.
2. In combination with a radial-tube steam boiler, a steam drying and super-
heating apparatus adapted for subdividing and distributing the whole volume of
steam in small streams and subjecting them to extended drying and superheating
surfaces, said apparatus comprising an outer steam chamber having a series of
tubes closed at their outer ends and extending radially into the hot air chamber
of the boiler shell,-a central steam chamber closed at one end,-a series of smaller
open ended tubes radiating from said central chamber into the outer series of tubes
and a deflecting cylinder in the central steam chamber, substantially as described.
3. In a radial tube boiler a steam drying and superheating apparatus.comprising
a steam distributing chamber closed at top and opening at the bottom into the
stand-pipe, a surrounding steam discharge chamber closed at the bottom, and a
series of distributing pipes radiating from the distributing chamber, substantially
as described.
4. In combination with the stand-pipe a diaphragm plate, having an opening, a
steam distributing chamber connecting therewith at its opening and closed at the
top, the annular discharge chamber and a series of distributing pipes, connecting
with said distributing chamber, and ending in said discharge chamber, substantially
as described.
5. In combination with the stand-pipe, a central steam distributing chamber

page_text: closed at the top and open at the bottom, a surrounding discharge chamber closed
at the bottom, by a diaphragm plate connected to the stand-pipe, and having a
series of radial superheating tubes, and a series of steam distributing pipes leading
from said distributing chamber into the outer superheating tubes, substantially as
described.
6. In combination with the stand-pipe a steam distributing chamber closed at
the top and containing an open ended pipe or cylinder communicating with the
stand-pipe, a discharge chamber surrounding said distributing chamber, and a
series of distributing pipes radiating from the distributing chamber, substantially
as described.
7. In combination with the steam dome of a boiler, the diaphragm plate having
a central opening, and a distributing chamber, connecting with the plate at said
opening and having numerous small outlets for dividing the stean into numerous
currents or streams, said diaphragm-plate and distributing chamber formning a
discharge chamber in the dome, substantially as described.
8. The central stand-pipe of a radial tube steam boiler composed of one or more
sections of wrought or rolled metal plates having vertical lap welded seams, in
combination with the radial tubes set in close regular order around the entire
circumference of the stand-pipe, whereby the formation of a vertical flue or flues
resulting from riveted seams, is avoided and a more uniform heat obtained.
9. In a radial tube boiler the stand-pipe formed of one or more sections having
vertical lap-welded seams, the portion above the fire box or deflector, c, having
radial tubes set in close regular order around its entire circumference, and the fire
box section or portion having circumferential corrugations, substantially as
described.
1
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.