Improvements in Steam Generators.
Year: 1894

page_text: Date of Application, 19th Nov., 1894-Accepted, 22nd Dec., 1894
COMPLETE SPECIFICATION.
Improvements in Steam Generators.
We, THOMAS LEGGETT STURTEVANT, of Adams Street, Quincy, Norfolk
County State of Massachusetts, United States of America Lawyer and THOMAS
JOSEPH STURTEVANT, of Winthrop Street, Framingham, Middlesex County,
State of Massachusetts, United States of America, Electrical 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 steam generators in which the several sections, adapted
for multiplication, are composed of pipes and connected in series.
The chief feature is embodied in the construction of the steam generating section,
which is made up primarily of two tubes, one secured within the other, the
inside tube being open at both ends, while the upper end of the outside tube is
closed and water circulation between the two tubes is obtained by employing a
series of U pipes having one set of extremities inserted in the outside tube, while
their opposite ends enter the enlarged upper part of the inside tube.
Hence the
circulation commences as the water is drawn from the space between the two tubes
upwardly and through the U pipes into the closed end of the inside tube, whence it
courses down and through said inside tubes to the bottom and again commences
another circuit through the outside tube.
:-
Secondly This form of generator embodies several advantages of construction,
among them being that all the sections are easily formed and are readily removable,
while ample opportunity is afforded for expansion and contraction under working
conditions. The steam drum or drums are so placed that all the water carried in is
immediately drained out, and in this respect is a characteristic and important
feature.
A further feature is embraced in a series of water pipes supporting the grate
bars which in this way may be made lighter. In connection with the steam
generating tubes one or more perforated pipes are employed which are adapted to
receive steam and by its escape to free the exterior of the tubes from soot. This is
a most important feature.
In the endeavour to create steam rapidly and at the same time to deliver it in a
dry condition, the steam generating tubes are so united with the separators that
steam and water which enter the latter are given a rotary or circular motion in
order to separate the water from the steam thereby allowing the water to pass
downwardly while the steam escapes in a dry condition to the drums adapted to
receive it.
The drawings accompanying this Specification represent in Fig. 1 a sectional
clevation of a steam generator embodying our invention.
Fig. 2 is a section on line 1. 1.
Fig. 3 shows a modification in the mode of uniting the various sections.
Fig. 4 is a vertical section enlarged on line 2. 2.
Fig. 5 is a similar view likewise enlarged on line 3. 3.
Fig. 6 is a longitudinal section showing one form of construction.
:
Fig. 7 is a plan showing the arrangement of the U pipes in the vertical side pipes
as in Fig. 9.
Fig. 8 is a section of casting to illustrate one form of centrifugal partition on

page_text: Fig. 9 is a transverse, vertical, sectional elevation of a generator adapted as a
double furnace.
Fig. 10 is a sectional plan on line 4. 4.
Fig. 11 is a vertical cross section showing the end tubes and a modified arrange
ment of the U.tubes.
Fig. 12 is a longitudinal section of a generator under our invention.
Fig. 13 is an end elevation of the generator showing the pipes at one end of
fire box.
Fig. 14 shows a modified form of generator section.
In said drawings 2 represents the essential parts of a steam generator, as an
assemblage contained within a casing 3 and furnished with a stack 4 and grate-
bars 5, as ordinarily. The steam generating sections shown at 6, when properly
grouped form the side and top walls of the combustion chamber. Each section
consists primarily of a base or fitting 7, which constitutes a water-leg and from
which rises a tube 8 termed a side pipe since when grouped they form the sides of
the fire chamber; the said tube is surmounted by a header 9, termed a separator.
Said tube is stopped off by a ring or partition 10 or otherwise at the top, while a
second or return tube 12 is contained within the first being somewhat reduced in
one portion in order to leave a space 13 between the two tubes. Hence the
circulation is as indicated, the hottest water with commingled steam rises up
through the side tubes 8, courses through the U tubes and enters the header 9
where the steam and water are separated. The latter returns to the water leg by
way of the circulating tube 12 which is cooler than the outside tube, while the
steam rises and escapes into the drum or drums 16, 16, 18, 18¹.
In connection with these two tubes, a series of U pipes 14 are provided and the
opposite extremities entered on each side of the stop 10, as shown, one set entering
the outside tube below the stop, the other set terminating in the separator 9 which is
an enlarged continuation of the inside tube. But since the outside tube is of
considerable diameter and to have the steam generating pipes occupy about equal
space said pipes are arranged as shown in Figs. 2 and 3 and more rapid circulation
is effected. To secure said pipes to the tubes two circular plates 20. 21 are
employed; one being affixed to the separator facing the fire-box, the other to the
cap forming a part of the outside tube and facing the fire-box. The upper plate is
made fast by means of a bolt, the lower one by a series of fastening screws. Into
said plates are entered the ends of the U steam generating pipes which are so
arranged, as before stated, as to occupy nearly the same distance lengthwise of the
generator, as the outside tube. In Fig. 3 in lieu of the plates the pipes 14 are
entered directly into the header and there are three rows inserted to nearly fill up
the space corresponding to that occupied by the outside tube.
The U pipes furthermore extend inwardly and form the upper wall of the
combustion chamber in connection with similar pipes from the opposite co-operating
pipe sections.
In the construction of a generator, the several sections in some instances are
connected in series with a water drum 15, which may extend about three sides of
the fire-box. In lieu of this arrangement the water drum may he omitted from the
generator and the several fittings 71 united, which together act to form a water
drum, the lateral water drums being in this last instanced construction united by a
cross pipe 25 as before.
We are aware that steam generators have been constructed in which vertical
steam. and water tubes are supplied with bent pipes which lead from and are
returned to the same tube, but these have comparatively feeble circulation. On
the contrary, our invention has for its object an increase in the circulation, and in
order to carry it into effect in lieu of a single tube, two vertical tubes are employed
by us. The outer is closed at the top, while the bent steam generating pipes
extend from this point and terminate in a chamber which is merely an extension of
the inside tube. Our vertical outside tube is a water tube only, the rising liquid
therein being forced out at the upper closed end and passed into the steam

page_text: generating pipes, whence it is delivered into the separator or upper end of the
inside tube, and from there gravitates through the inside tube coursing within the
latter and emerging into the opposite end of the outside tube, thus the path
travelled by the hot water is entirely natural and a very strong and rapid circulation
is obtained.
In operating a generator of this class the circulation is as follows; presuming the
proper amount of water has been introduced and heat applied. This heat being
first communicated to the water in the space 13 and pipes 14, said water rises by
difference in gravity between it and that contained within the inside tube 12, which
is cooler. As the water and steam, enter the upper portion of the tube 12 they are
separated, the water flowing down through the inside tube and emerges into the
base 7, whence it again ascends through the space 13. The steam, on the other
hand, rises and escapes into the pipe 17, which leads preferably to a steam drum 18
for use.
In some instances this form of generator section may be applied to a double
furnace and is then generally provided with a water base composed primarily of
cylinders or water legs 15, 151, 152, while sometimes only a single central cylinder 15*
is employed to act as a mud drum, see Fig. 9. The circulation through the various
parts is such, the water entering the top portion of said drum or drums and again
withdrawn from said top portion, that the dirt or sediment is allowed to fall to the
bottom of said drum or drums and settles in this, the least disturbed portion of the
generator. The general circulation is as indicated by the arrows.
In order to more completely separate the water and steam and thus produce the
latter in a dry condition, we have so arranged the parts that the steam and water
when they enter the chamber of the separator shall be given a rotary motion. In
some instances, as shown in Figs. 7 and 9 the steam generating tubes 14, enter the
separator tangentially, hence as the liquid strikes the curved walls of the separators
a centrifugal effect is produced and the water thus quickly separates and gravitates,
while the steam escapes upwardly. As shown in Figs. 5 and 8 when said pipes
enter radially some mechanical device in the shape of a curved shield or deflector 19
is fitted within the separator and opposite the delivery ends of the generating
tubes.
The fire box surface is by far the most efficient steam making surface,
therefore we have arranged to make this surface as large as possible and in
every part to provide for a short and rapid circulation of the water. Our
improvements are particularly applicable to double furnaces in which event a
central row of upright tubes 23 is provided. These are united with L pipes 24,
which are alternately connected with opposite separators as shown in Fig. 9.
In other words the first Ŀ pipe 24 terminates in the separator on the left, the
next pipe in the separator on the right. In Figs. 7 and 9 the U pipes are
adapted to extend completely across the fire box, while in Figs. 5, 11, 13 and 14
only to the centre. But this is a mere matter of preference and does not alter
the function nor depart from the spirit of our invention.
To further increase the pipe surface of the fire box, the water legs or
drums 15. 151 are sometimes omitted as in Figs. 9 and 10, while a series of
pipes 26 are arranged transversely beneath the grate bars 5. Since the latter
are supported thereby, the weight of said bars may be materially lessened.
By the construction above premised, the fire box is now provided with steam
generating and water circulating pipes upon the top, bottom and both sides. To
still further increase the capacity and efficiency of said generator and to be able to
obtain all the heat possible from escaping gases and other products of combustion,
a group of pipes 27 is located at the rear end or back of the generator. These rise
from the water leg 152 until just before they reach the under surface of the
U tubes said pipes 27 are bent and then extend longitudinally above the fire b>x
and just beneath the U tubes. When they reach the front of the generator
they rise, take a second upward turn and terminate in a lateral arm or
arms 28 28¹ from the side sections at this point. From their general direction

page_text: and shape we term them intermediate or Z pipes since they intervene between
the grate surface and the general under surface created by the U pipes taken
collectively. In a pipe steam generator much of its efficiency depends upon having
the exterior surface of the pipes free from soot. This is not an easy result
to obtain.
upon
the exterior
It frequently happens that soot or unconsumed carbon collects
surface of these various pipes which compose a generator. To remove this
substance which acts to materially diminish the effects of the fire we propose to
introduce a perforated pipe or pipes 29 which extend within the generator and
are preferably in the present instance located in the central space formed by
the U tubes as shown. These pipes are joined to the steam space of the generator
and are controlled by a valve 30, see Fig. 12. Hence whenever it may be
necessary steam is allowed to enter said pipes and issues in the form of jets which
sweep the exterior of the various groups of pipes clean, and keep them in the best
condition to receive the influence of heat units. These pipes may be rotated, as
shown in Fig. 12, by aid of a hand wheel 31, so as to more thoroughly sweep
the surfaces.
In these several drawings there are a few variations in the structural arrange-
ment, but merely introduced to show their application for large or small steain
generators. Thus Figs. 11, 13 and 14 are suitable for a small class of boiler and
have the water base in the form of the cylinders 15 151 152 while a single steam
drum 163 is supplied, the separators being joined thereto by cross pipes. On the
other hand Fig. 9 is intended for a larger capacity and the said water legs are
omitted, while three steam drums more or less are supplied and a single central
water leg or a mud-drum is added.
In Fig. 14 the vertical pipes 23 in lieu of rising from a common base pipe and
being joined with the L pipes as shown in Fig. 9 are connected directly at the
bottom to the water legs, and at the top are united by lateral pipes 24ª to the
opposite, but corresponding vertical side pipes.
In providing a water supply and at the same time to increase the circulation we
propose to extend the feed pipe 32 within the rear water leg from which rise the
series of vertical end pipes. That portion of the feed pipe within the water leg is
perforated, the said holes being arranged to correspond with the position of said
end pipes. In lieu of the holes short pipes 34 may be inserted in the feed pipe and
such may extend just into the lower ends of said vertical pipes. This arrangement
is adapted on account of the length of the said pipes 27 which are most exposed to
heat. Hence when water is admitted under pressure it enters the group of pipes
and by injector action the rapidity of the circulation in this special group of pipes
is increased, the fluid supply passing directly into them.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :--
1. A steam generator section comprising an outer steam generating tube closed
at its upper end, an inner return tube extended within said outer tube and open at
both ends, and a series of steam generating tubes which extend laterally within the
combustion chamber and connect the upper ends of the said outer and inner tubes,
substantially as described.
2. In a steam generator section, the combination with a header having two
compartments, of a steam generating pipe entering one of said compartments, a
return pipe connecting the other of said compartments with said steam generating
tube, and a series of laterally extending steam generating pipes connecting said
compartments, substantially as described.
3. In a steam generator section, the combination with a header having a dividing
partition forming two compartments, of an outer steam generating pipe opening
into one compartment of said header at a point below said partition, an inner
return tube depending from said partition and connecting said outer tube with the

page_text: other compartment of said header, and laterally extending steam generating pipes
which enter said header at points above and below said dividing partition and
form connections between the two compartments of said header, substantially as
described.
5 4. In a steam generator section, the combination with a header, of an outer
steam generating tube entering said header, a partition which divides the latter
and closes the end of said steam generating tube, an inner return tube depending
from said partition aud connecting the other portion of said header with the
lower end of said outer steam generating tube, and a series of U-shaped steam
generating pipes which extend into the combustion chamber and enter said header
at points above and below its dividing partition, substantially as described.
"
5. In a steam generator section, the combination with an outer steam generating
tube, and an inner return tube, of a header having two compartments one of which
forms a continuation of said outer tube and the other a continuation of, said
inner tube, and a series of laterally extending steam generating pipes which
connect the upper ends of said outer and inner pipes, substantially as described.
6. A steam generator containing one or more base water legs or mud drums, a
central group of steam making pipes rising therefrom, and bottom cross-tubes or
grate-supporting pipes, combined with vertical steam-making side pipes, separators
which surmount said side pipes, together with means for connecting the central
vertical pipes with said separators, substantially as shown.
7. In a steam generator, the combination, with a mud drum, of two parallet
groups of vertical side pipes, a series of centrally disposed vertical pipes, and a
series of horizontal L-tubes which connect said central pipes alternately with
opposite side pipes, substantially as described.
8. A steam generator having in combination one or more mud drums or water legs,
two series of opposite steam making side pipes, separators which surmount each
pipe, a system of Ụ steam-making tubes, connected at one end with the side pipes
at the opposite end with the separator, and a series of steam-making central pipes
connected with said mud drum and terminating in the side separators, and means
for discharging the steam from said side separators into a steam-collecting reservoir,
substantially as set forth.
9. A steam generator having in combination a series of upright steam-making
side pipes, a water base common to the series, separators adapted to surmount each
upright pipe, a series of U-shaped steam-making tubes leading from said upright
pipes and terminating in a separator, and means by which centrifugal motion is
imparted to the water entering the separators, substantially as specified.
10. The combination in a steam generator section comprising an upright steam
and water pipe, and a separator thereupon, of a curved plate within the separator,
a series of U pipes leading from said separator, and a return pipe adapted to
conduct the water in the separator to the base of the steam and water pipe,
substantially as stated.
11. In a steam generator provided with a water base, a series of side pipes
vertical therefrom, a group of U tubes transversely from each of said side pipes, a series
of end pipes rising from said water base and arranged to extend longitudinally of
the generator beneath the U tubes, said longitudinal pipes terminating in an arm
or projection from a vertical side pipe, substantially as shown.
12. In steam generating sections an upright vertical steam and water pipe, a
separator thereupon, and a series of U tubes adapted to enter the separator
tangentially in order to produce a centrifugal motion to liquid as it enters,
substantially as explained.
13. A steam generating section comprising an upright vertical steam and water
pipe, a separator which surmounts said pipe, a curved partition in said separator,
and a series of U pipes adapted to discharge behind the partition, substantially as
described.
14. In a steam generator, the combination with a series of vertical steam
generating pipes, of separators mounted thereon, U-shaped pipes carried thereby,

page_text: and revoluble, perforated steam pipes positioned in the bend of said U-shaped pipes,
for the purposes and substantially as described.
15. A steam generator having a series of vertical steam-making side pipes,
separators which surmount said pipes, and tubes to connect said side pipes with the
separator and adapted to create centrifugal currents, combined with return pipes
interiorly of said side pipes and adapted to convey water carried over by the steam
to the base of the generator, substantially as specified.
16. A steam generator having a series of vertical side pipes, a water drum to
which said pipes are connected, separators to surmount each side pipe, U shaped
pipes communicating with said separators, a lateral arm upon two side pipes, com-
bined with a group of pipes which lead from said water drum lengthwise of the fire-box
beneath the U-pipes and terminate in the said lateral arms, all substantially as
explained.
17. In a steam generator, the combination with a water-drum, of a series of
intermediary or Z-pipes carried thereby and connecting said drum with a lateral
arm 17 at the other end of the combustion chamber, and a feed pipe located
centrally of said water drum and having injector pipes which enter the lower
members of said 2-pipes, substantially as described.
18. A steam generator having in combination a series of upright steam-making
side pipes, a water base common to the series, a separator adapted to surmount
each side pipe in the series, a group of U shaped steam-making tubes leading from
said upright pipes and terminating in a separator, and one or more perforated soot-
removing pipes, all operating as explained.
Dated this Fifth day of November 1894.
THOMAS LEGGETT STURTEVANT.
THOMAS JOSEPH STURTEVANT.