Improvements in Apparatus for Superheating Steam.
Year: 1891

page_text: Date of Application, 2nd Apr., 1891
Complete Specification Left, 2nd Jan., 1892-Accepted, 6th Feb., 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Superheating Steam.
I, EMILE SCHWÖRER, of Colmar, Alsace, Engineer, do hereby declare the
nature of this invention to be as follows:-
This invention has reference to apparatus for superheating steam and is more
particularly designed to provide an improved superheating apparatus for use in
connection with stationary boilers. The invention comprises improvements in the
arrangement of such apparatus in relation to the boiler furnace; and in the con-
struction of the superheating tubes or conduits.
One object of the invention is to increase the working capacity of steam
superlicating apparatus, and at the same time to considerably restrict the dimensions
thereof. An important feature of my invention consists in arranging the superheater
beneath or in proximity to the furnace or combustion chamber in such a manner
that the superheating can be effected according to requirements either by radiant
heat alone, or by the joint action of radiant heat and the fire gases or products
of combustion from the boiler furnace. A further important feature of this
invention consists in the arrangement in the superheating tubes or in the steam
conduits connected therewith, of battles which offer considerable resistance to the
passage of steam and have a very favorable influence on the superheating of the
steam.
The invention further relates to the employment of special ribbed tubes for the
steam superheating apparatus.
In the accompanying drawings I have shewn how my said invention may be
conveniently and advantageously carried into practice.
Fig. 1 is a longitudinal vertical section through a steam boiler furnace fitted
with steam superheating apparatus according to this invention, the boiler being
shown in elevation.
Fig. 2 is a transverse section thereof; and
Fig. 3 is a horizontal section through the flues surrounding the boiler which is
shown in plan.
Fig. 4 is a horizontal section taken at the level of the water tubes hereinafter
referred to.
Fig. 5 is a plan of the superheating apparatus, the surrounding brickwork being
shown in horizontal section.
Figs. 6 to 21 illustrate in section various forms of steain superheating tubes
according to this invention.
The main boiler A, whose special construction may of course be considered as of
secondary importance, is connected with the water tubes B by means of the short
communication tubes d.
The firing, which is shown as underneath firing, is effected from the grate F.
The superheater D which is situated in the chamber G, is separated from the
combustion chamber or flue by the ceiling or partition El, so that it can be acted
upon by radiant heat, and also by the flames or products of combustion passing
over the fire bridge E and entering the chamber G. The superheating tubes
are preferably protected from too violent action of the flame, by a protective metal
sheet against which the flame will strike. This protective metal sheet is preferably
arranged immediately in front of those parts of the superheating tubes upon which
the flame would impinge. A second protective sheet placed at the upper part of
the outlet of the chamber G forces the gases downward before they enter the
succeeding conduits.
The moist highly heated gases thus tend to come in contact with the superheating
apparatus. The sheets are not shown in the drawings.

page_text: In order to enable the degree of superheating to be varied within certain limits,
there is employed an arrangement as follows:-
Abutting against the rear end of the ceiling or partition E', is a double flap or
damper which controls the passages leading to the boiler flue and also the
entrance to the steam-superheating chamber. This flap may be adjusted by any
suitable device as for instance by a suitable lever or operating device cc³, in such
a manner that the whole of the flame can be caused to pass either round the
boiler, or only around the steam superheater as may be desired, while by partially
opening each damper it is also possible to adjust the same in such a manner
that both the boiler and superheater shall be acted upon at the same time by
the flames or products of combustion. G is a passage for the exit of the fire
gases from the steam superheating chamber G. In some instances one damper
only, to check the entrance to these last flues has been found to be both effective
and practicable. The arrangement of the superheater in the manner herein before
described affords the great advantage of almost wholly obviating even after a very
long time the deposition of soot which usually has a serious disturbing effect and
interferes to a great extent with the efficient working of superheating apparatus
as heretofore employed.
In the arrangement shown steam is supplied to the superheater, from the dome C
of the boiler through one or more tubes a', each furnished with a cock h'. After
passing through the superheater the steam is carried off by a pipe b provided with
a stop valve or cock h³. A pipe a provided with stop valve or cock in com-
munication with the dome C and with the pipe b, serves to allow steam to be added
directly from the boiler to the superheated steam as desired. Figs. 6-21, illustrate
some convenient forms of ribbed superheating tubes.
Figs. 6 and 7 illustrate a longitudinal and transverse section respectively a steam
superheating tube R provided externally and internally with ribs r, arranged at
right angles to the axis of the tube. These ribs may be continuous or may consist
of a number of short lengths or of projections.
Figs. 8 and 9 illustrate also in longitudinal and transverse section respectively,
a tube R in which all the ribs are arranged parallel with the longitudinal
axis of the tube. The internal ribs r nay, as shown in the drawing, be arranged
to alternate with the outer ribs r.
In the tube R illustrated in Figs. 10 and 11, the outer ribs are parallel with
the longitudinal axis of the tube, whilst the inner ribs are arranged at right
angles to the said axis.
In Figs. 12 and 13, the arrangement of the ribs is the converse of that shown in
Figs. 10 and 11.
Figs. 14 and 15, illustrate a tube R similar to that shown in Figs. 12 and 13 but
with the addition of internal baffle plates e against which the steam strikes in
flowing through the said tube, and which compel the steam to come into close
contact with the hot walls of the tube.
Figs. 16 and 17 illustrate a tube R in which the baffle plates w arc attached,
not to internal ribs, but directly to the inner side of the tube at points around the
circumference thereof, the baffle plates being arranged as indicated so as to cause
or tend to cause the steam to take a twisted or zig-zag course.
Figs. 18 and 19 illustrate a tube in which the battle plates are held in place
by radial arms.
In Figs. 20 and 21 the connection pipe R' between the boiler and
the superheating apparatus is shown with a spiral-piece inserted, to compel the
steam to come into contact with the hottest part of the tube and to impart to it a
spiral motion. The outer or inner ribs r may also form continuous spiral lines,
a very satisfactory result being obtained with tubes having the ribs thus arranged.
It is also to be noted that the insertion or baffle plates need not necessarily be
always arranged at right angles to the longitudinal axis of the tube, as shown in
the drawings, but can be arranged at any angle of inclination without departing
from the nature of my invention.
The simplest modes of construction of steam superheating tubes, viz., tubes with

page_text: only external or only internal ribs, and with otherwise smooth walls, have, not
been illustrated as such constructions will be readily understood without drawings.
Moreover casings or troughs of square or other suitable section may be substituted
for the tubes described.
With respect to the employment of superheating tubes with ribs according to
this invention, it may be stated in the first place, that their use is most suitable
where the greatest possible utilization of the heat from the products of combustion
is desired or is necessary. These tubes may however be employed with advantage
in all cases in which restriction of the dimensions of the steam superheating
apparatus is requisite or desirable.
The employment of superheating tubes having internal ribs, or external ribs, or
both internal and external ribs, depends on the particular circumstances of the
working of the steam superheating apparatus and it unnecessary to discuss in
detail all possible cases. It may be stated however that in apparatus in which an
efficient utilization of the heat in fire gases is to be combined with minimum
dimensions of the apparatus, it is preferable to employ tubes having both internal
and external ribs.
In cases where the greatest utilization of the fire gases is desired, I prefer to use
tubes provided with internal and external ribs, and with insertion or battle plates w.
If desired, wings vanes or spirals may also be employed in the steam supply
tubes. When the tubes are exposed to the action of a powerful flame or of highly
heated products of combustion I have found it desirable to employ tubes having
external ribs, the durability of the said tubes being thereby very considerably
increased.
The result which may be obtained by means of external ribs, is thus two-fold
the heating surface is considerably augmented, and the durability of the tubes is
greatly increased.
Furthermore it should be noted that the ribs enable the deposition of soot to be
almost entirely obviated.
It will be readily seen that in some cases the superheating of the steam may be
effected by causing the same to pass around the exterior of the tubes herein before
described, whilst the fire gases are made to pass through the interior of the said
tubes. In this case the mantle surrounding the tubes can also be provided with
the different arrangements of ribs and be heated externally.
Dated this 2nd day of April 1891.
E.
SCHWORER.
By L. W., per F. B.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Superheating Steam.
1, EMILE SCHWÖRER, of Colmar, Alsace, 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 has reference to apparatus for superheating steam and is more
particularly designed to provide an improved superheating apparatus for use in
connection with boilers. The invention comprises improvements in the arrange-
ment of such apparatus in relation to the boiler furnace; and in the construction
of the superheating tubes or conduits.
One object of the invention is to increase the working capacity of steam super-
heating apparatus, and at the same time to considerably restrict the dimensions
thereof. An important feature of my invention consists in arranging the super-
heater beneath or in proximity to the furnace or combustion chamber in such a
manner that the superheating can be effected according to requirements either by
radiant heat alone, or by the joint action of radiant heat and the fire gases or

page_text: products of combustion from the boiler furnace. A further important feature of
this invention consists in the arrangement in the superheating tubes or in the steam
conduits connected therewith, of battles which offer considerable resistance to the
passage of steam and have a very favorable influence on the superheating of
the steam.
The invention further relates to the employment of special ribbed tubes for the
steam superheating apparatus.
Referring to the drawings filed with my Provisional Specification,
Fig. 1 is a longitudinal vertical section through a steam boiler furnace fitted
with steam superheating apparatus according to this invention, the boiler being
shewn in elevation.
Fig. 2 is a transverse section thereof; and
Fig. 3 is a horizontal section through the flues surrounding the boiler which is
shewn in plan.
Fig. 4 is a horizontal section taken at the level of the water tubes hereinafter
referred to.
Fig. 5 is a plan of the superheating apparatus, the surrounding brickwork being
shewn in horizontal section.
Figs. 6 to 21 illustrate in section various forms of steam superheating tubes
according to this invention.
The main boiler A, whose special construction may of course be considered as of
'secondary importance, is connected with the water tubes B by means of the short
communication tubes d.
The firing, which is shewn as underneath firing, is effected from the grate F.
The superheater D which is situated in the chamber G, is separated from the
combustion chamber or flue by the ceiling or partition E', so that it can be acted
upon by radiant heat, and also by the flames or products of combustion passing
over the fire bridge E and entering the chamber G. The superheating tubes are
preferably protected from too violent action of the flame or hot gases by a pro-
tective sheet against which the flame will strike. This protective sheet is preferably
arranged immediately in front of those parts of the superheating tubes upon which
the flame would impinge. A second protective sheet placed at the upper part of
the outlet of the chamber G forces the gases downward before they enter the
succeeding conduits. The most highly heated gases thus tend to come in contact
with the superheating apparatus and increase the efficiency thereof. The sheets
are not shewn in the drawings.
?
To enable the degree of superheating to be varied within certain limits, there is
employed an arrangement as follows:-Abutting against the rear end of the
ceiling or partition E', is a double flap or damper c c which controls the passages
leading to the boiler flue and also the entrance to the steam superheating chamber.
This flap may be adjusted by any suitable device as for instance by a suitable lever
or operating device in such a manner that the whole of the flame can be caused
to pass either round the boiler, or only around the steam superheater as may be
desired, while by partially opening each damper it is also possible to adjust the
same in such a manner that both the boiler and superheater shall be acted upon at
the same time by the flames or products of combustion. G is a passage for the
exit of the fire gases from the steam superheating chamber G. In some instances
one damper only, to check the entrance to these last flues has been found to be
-both effective and practicable. The arrangement of the superheater in the manner
hereinabove described affords the great advantage of almost wholly obviating,
even after working for a very long time, the deposition of soot which usually has
a serious disturbing effect and interferes to a great extent with the efficient working
of superheating apparatus as heretofore employed.
In the arrangement shewn, steam is supplied to the superheater, from the
dome C of the boiler through one or more tubes a' each furnished with a cock h¹.
After passing through the superheater the steam is carried off by a pipe b pro-
vided with a stop valve or cock h³. A pipe a³ provided with stop valve or cock h

page_text: and in communication with the dome C and with the pipe b, serves to allow steam
to be added directly from the boiler to the superheated steam as desired. Figs. 6-21
illustrate some convenient forms of ribbed superheating tubes.
ا.
Figs. 6 and 7 illustrate in longitudinal and transverse section respectively a
steam superheating tube R provided externally and internally with ribs
arranged at right angles to the axis of the tube. These ribs may each be con-
tinuous or may be composed of a number of short lengths or of projections.
Figs. 8 and 9 illustrate also in longitudinal and transverse section respectively, a
tube R in which all the ribs rare arranged parallel with the longitudinal axis of
the tube. The internal ribs may, as shewn in the drawing, be arranged to
alternate with the outer ribs r.
In the tube R illustrated in Figs. 10 and 11, the outer ribs are parallel with
the longitudinal axis of the tube, whilst the inner ribs rare arranged at right
angles to the said axis.
In Figs. 12 and 13, the arrangement of the ribs is the converse of that shewn in
Figs. 10 and 11.
Figs. 14 and 15 illustrate a tube R similar to that shewn in Figs. 12 and 13 but
with the addition of internal baffle plates w against which the steam strikes in
flowing through the said tube, and which compel the steam to come into close
contact with the hot walls of the tube.
Figs. 16 and 17 illustrate a tube R in which the baffle plates are attached, not
to internal ribs, but directly to the inner side of the tube at points around the
circumference thereof, the baffle plates being arranged as indicated so as to cause
or tend to cause the steam to take a twisted or zig-zag course.
Figs. 18 and 19 illustrate a tube in which the baffle plates w are held in place
by radial arms. In Figs. 20 and 21 the connection pipe R' between the boiler and
the superheating apparatus is shewn provided with corrugated or undulating
strip to compel the steam to come into contact with the hottest part of the tube
and to impart to it a zig-zag motion. The outer or inner ribs may also form
continuous spiral lines, a very satisfactory result being obtained with tubes having
the ribs thus arranged.
It is also to be noted that the insertion or battle plates need not necessarily be
always arranged at right angles to the longitudinal axis of the tube, as shewn in
the drawings, but can be arranged at any angle of inclination without departing
from the nature of my invention.
The simplest modes of construction of steam superheating tubes, ciz., tubes with
only external or only internal ribs, and with otherwise smooth walls, have not
been illustrated as such constructions will be readily understood without drawings.
Moreover casings or pipes of square or other suitable section may be substituted for
the cylindrical tubes described.
With respect to the employment of superheating tubes with ribs according to
this invention, it may be stated in the first place, that their use is most suitable
where the greatest possible utilization of the heat from the products of combustion
is desired or is necessary. These tubes may however be employed with advantage
in all cases in which restriction of the dimensions of the steam superheating
apparatus is requisite or desirable.
The employment of superheating tubes having internal ribs, or external ribs, or
both internal and external ribs, depends on the particular circumstances of the
working of the steam superheating apparatus, and it is unnecessary to discuss in
detail all possible cases. It may be stated however that in apparatus in which an
efficient utilization of the heat in fire gases is to be combined with minimum
dimensions of the apparatus, it is preferable to employ tubes having both internal
and external ribs..
In cases where the greatest utilization of the fire gases is desired, I prefer to
use tubes provided with internal and external ribs, and with insertion or baffle
plates c. If desired, wings vanes or corrugated or zig-zag strips may also be
employed in the steam supply tubes. When the tubes are exposed to the action

page_text: of a powerful flame or of highly heated products of combustion I have found it
desirable to employ tubes having external ribs, the durability of the said tubes
being thereby very considerably increased.
The result which may be obtained by means of external ribs, is thus two-fold,
the heating surface is considerably augmented, and the durability of the tubes is
greatly increased.
Furthermore it should be noted that the ribs enable the deposition of soot to
be almost entirely obviated.
It will be readily seen that in some cases the superheating of the steam may
be effected by causing the same to pass around the exterior of the tubes herein-
before described, whilst the fire gases are made to pass through the interior of the
said tubes. In this case the mantle surrounding the tubes can also be provided with
the different arrangements of ribs and be heated externally.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. In apparatus for superheating steam, a superheater consisting of elements or
tubes either plain or provided with ribs or projections, and arranged in a furnace
chamber or flue located below or in proximity to the combustion chamber or flue
of the boiler so that the superheating can be effected by the radiant heat as well
as by the direct action of the hot gases and products of combustion, as herein
described and shown in the drawings annexed.
2. The use in conjunction with apparatus for superheating steam arranged as
referred to in the preceding claim, of an adjustable damper c¹² adapted to
simultaneously control the flow of hot gases and products of combustion passing to
the chamber or flue containing the superheater as well as those passing to the
boiler Hue, so that the said hot gases and products of combustion can be caused
to act either upon the superheater alone, or upon the boiler alone, or upon both,
the superheater and boiler simultaneously, as hereinbefore described.
3. Apparatus for superheating steam comprising tubes each provided externally
with continuous or interrupted ribs or with outwardly extending projections,
arranged at right angles or inclined or spirally arranged at any other desired
angle with the longitudinal axis of the tube, substantially as described and shown
for the purpose specified.
4. Apparatus for superheating steam, comprising tubes each provided internally
with continuous or interrupted ribs or with outwardly extending projections arranged
at right angles or inclined or spirally arranged at any other desired angle with the
longitudinal axis of the tube, substantially as described and shown for the purpose
specified.
5. Apparatus for superheating steam, comprising superheating tubes each
provided both internally and externally with continuous or interrupted ribs or with
projections or with undulations arranged at any desired angle with the longitudinal
axis of the tube as specified.
6. The arrangement in the tubes or in each tube of steam superheating apparatus,
of fixed or movable baffle plates or obstacles extending across the centre of the
tube and against which steam flowing through the tube will strike, these baffle
plates or obstacles being arranged either at right angles or at any other suitable
angle with the longitudinal axis of the tube, the superheating tube or tubes, being
of the form hereinabove described for the purpose specified.
Dated this 2nd day of Januar 1902
E. SCHWÖRER.
By L. W., per F. B.