Improvements in and connected with Superheaters for Tubular Boilers.
Year: 1898

page_text: Reprinted as amended in accordance with the decision of the Supervising Examiner
acting for Comptroller General, dated the 22nd day of October 1906
Date of Application, 24th Oct., 1898
Complete Specification Left, 6th July, 1899 - Accepted, 24th Oct., 1899
PROVISIONAL SPECIFICATION.
Improvements in and connected with Superheaters for Tubular
Boilers.
1, WILHELM SCUMIDT, of Wilhelmshöhe near Cassel, in the Province of Hesse-
Nassau, German Empire, Civil-Engineer do hereby declare the nature of this
invention to be as follows:-
This invention relates to superheaters for tubular boilers and has for its object
various improvements in the construction of the same.
With regard to the arrangement of superheaters upon tubular boilers, more
especially for marine boilers, locomotive boilers, portable engine-boilers and the
like, attention may be here directed to the fact in the preamble of the specification,
that, as is known, the arrangement of a superheater upon boilers of the above
mentioned description has been hitherto connected with great difficulty, where high
temperatures were to be attained without the construction of the boiler being con-
siderably altered, and where also it was not permissable to reduce the water
heating surface.
The solution of this problem has been regarded as virtually impossible with regard
to existing boilers to subsequently mount upon the same a suitable superheater for
the attainment of high degrees of temperature. More especially has this problem
been rendered difficult in view of the fact, that the fire-gases in these kinds of
boilers are usually already very considerably utilized
The problem is also not solved by changing the dimensions of the boiler:
If for instance the boiler were somewhat shortened, so that the waste or spont
gases become discharged in such manner that the same give off the entire amount
of their heat to the superheater, the superheater would have to be so large, that the
space in or above the smoke-chamber would not be sufficient to enable a super-
heater of such large dimensions to be employed, even, when any large space were
available for the arrangement of a superheater which as known, occurs only in the
rarest of cases.
The hereinafter described invention therefore, has for its object to solve the
abovementioned problem more especially with regard to already existing tubular
boilers without an altering of the boiler itself, or, in other words, to effect the
desired purpose by the arrangement or employment of the superheater of compara-
tively small dimensions.
To attain this end, I proceed in such manner, that I utilize a part of the heating
or fire-gases in the usual manner, and then conduct the same directly to the
chimney or stack, whilst I cause the other portion or remaining portion of the said
fire-gases to pass out of the boiler at a considerably increased temperature, the said
DO17

page_text: second portion of the fire-gases being in the smoke-chamber entirely separated
from the first mentioned portion of the fire-gases in the manner hereinafter more
fully described.
This varying utilization of the fire-gases within the boiler itself, i.e. the changing
temperature with which the same enters the smoke-chamber, is either attained by
the employment of isolating sockets a (Figure 6), located or arranged within the
fire-tubes, as shown in this figure, whereby it will be clear, that the said fire-gases
cannot come in contact with the fire-tubes proper, or, I may obtain the desired end
by imparting to a certain number of the fire-tubes an increased or extended
diameter in the manner represented in Figures 4 & 5 of the accompanying
drawing.
It will also be clear, that instead of giving, as hereinbefore indicated, a certain
number of the fire-tubes, a larger diameter, I may employ one single fire-tube
through which the fire-gases for the superheating could be led to the super-
heater.
The larger the diameter of the boiler-tube in proportion to their length, the
greater will be the temperature of the fire-gases entering the superheater, and,
inversely, the smaller, (in comparison), cau the heating surfaces of the superheater
be proportioned.
Figures 1, 2 & 3 of the accompanying drawing show my improved superheating
system as arranged for two marine-boilers, whilst Figures 4 & 5 show my super-
heating-system or superheater as arranged for locomotive-boilers or portable engine-
boilers. For this latter type of boiler it is especially necessary that the outer
dimensions of the superheating mantle should not be too large, for the reason, that
a suitable discharge of the gases and the especial arrangement of the heating tubes
within the same is of the greatest importance. Furthermore, in view of the fact,
that for this class of boiler artificial draught must be reckoned with, greater
resistance of the gases to the changing direction of the draught must be arranged
for.
In Figures 4 & 5 the direction which the fire-gases take, is clearly shown by the
arrows.
The separation or division of the hotter and colder gases in the interior of the
smoke-chamber is, in these figures, in contradistinction to the arrangement of my
superheating-system for marine-boilers, as shown in Figures 1-3 horizontally effected,
i.e. the gases here take an horizontal direction.
The fire-gases ejected from the upper and wide fire-tubes play around the inner-
superheating spiral b, when ascending, and reverse their direction at the upper end
of this spiral; in a downward direction the said gases pass the outer spiral cor
over the circular chamber formed by the mantle d, and unite at the lower end of
the stack with the colder gases which have, as hereinbefore indicated, already been
utilized in the boiler, whereupon these hotter gases in unison with the said colier
gases pass off or are discharged through the chimney or stack.
Dated this 24th day of October 1898.
GEO. H. RAYNER,
37 Chancery Lane London.
Agent for the Applicant.
Improvements in and connected with Superheaters for Tubular
Boilers.
I, WILHELM SCHMIDT, of Wilhelmshöhe near Cassel, in the Province of Hesse- 5
Nassau, German Empire, Civil Engineer do hereby declare the nature of this

page_text: nvention, 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 superheaters for tubular boilers and has for its object
various improvements in the construction of same.
With regard to the arrangement of a superheating device upon tubular boilers
more especially for marine boilers, locomotive boilers, portable engine boilers and
the like I beg to direct attention to the fact that the arrangement of a superheater
upon such boilers has been hitherto connected with great difficulty, especially when
bigh temperatures of steam were to be attained. The solution of this problem has
been regarded as virtually impossible with regard to existing boilers to subsequently
mount upon the same a superheater for the attainment of high temperatures for
the reason that generally the fire-gases in these kinds of boilers are already very
considerably utilized. The problem would not be solved when the dimensions of
the boiler were changed, if for instance the boiler were somewhat shortened, se
that-the to obtain gases of higher temperature to give a higher degree of superheating
and if these waste or spent gases, of higher temperature would transmit become
discharged-in-such-n-manner;-that-the-same-give-off the entire amount of their
remaining heat to the superheater, the same would have to be so large that the
available space in or above the smoke chamber would senreely in most cases not be
sufficient to take up accommodate a superheater of such large dimensions.
The object of the present application is to solve this problem and to enable an
arrangement of superheater of small dimensions upon tubular boilers. To attain
this purpose I proceed in such a manner, that I utilize a part of the heating or fire-
gases in the usual manner and then conduct it into the chimney whilst I cause the
other portion of the remaining gases to pass out of the boiler with a temperature
considerably high higher. This second portion of the fire-gases being in the smoke-
chamber entirely separated from the first mentioned portion of the fire-gases, is
conducted through-the-smoke-chamber to the superheater. The varying utilization
of the fire-gases within the boiler itself, that is to say the ehanging temperature
with which the same enter the smoke-chamber, is attained by insulating tubes
introduced into the fire-tubes so that the fire-gases cannot come into contact with
the fire-tubes proper. The same end is attained by imparting to a certain number
of the fire tubes an increased or extended diameter. Evidently a larger number of
fire-tubes of extended diameter can be replaced by a single flame-tube through
which the part of the heating gases serving for superheating purposes is led into
the superheater. The larger the diameter of these boiler-tubes in proportion to
their length, the greater will be the temperature of the fire-gases entering the super-
heater, and inversely.
My invention will be better understood with reference to the accompanying
drawing, in which:
Figure 1 shows a vertical section of a marine boiler provided with my superheat-
ing arrangement.
Figure 2 illustrates a top view of the same,
Figure 3 shows the same arrangement in side-view, partly in section,
Figures 4 & 5 represent in vertical and transverse section a modiñed construction
of my superheating arrangement for portable engine-boilers, more especially for
engines of small dimensions.
Figure 6 illustrates a boiler tube employed to take up the gases steam for super-
heating purposes.
In Figures 1 and 2 b is a steam pipe coming from the boiler; c is a dry steam-
pipe leading from the superheater and d represents the superheating tubes con-
nected to both pipes. The boiler-tubes are separated in two series by means of a
eireular wall e reaching to the top of the superheater. The space formed by the
arrangement of this wall can be brought more or less into connection with the space
surrounding the superheater by means of regulating flaps el suitably arranged on
the wall e. The gases passing through the boiler tubes a situated on-the outside of

page_text: the wall mantle e are utilized in the boiler and then ejected through the
chimney.
The boiler-tubes a situated within the space formed by the walls e are provided
Hed-out with tubes a' of insulating material for the purpose of preventing the
furnace gases passing through these tubes coming in contact with the boiler tubes
proper, thus retaining a higher temperature of the furnace gases. There gases
which passed through the inner tubes a provided with insulating tubes a' serve for
superheating purposes.
Owing to this special arrangement it is possible, that the outer diameter of the
superhea ering casing or superheatering mantle formed by the wall e may be very
small. For this reason this arrangement may be it-is advantageously employed in
engines where not much space is left to arrange a superheater.
Figures 4 & 5 represent in vertical and transverse section an arrangement more
especially suitable for portable engine-boilers. As in boilers of such kind forced
artificial draught must be reckoned with, greater resistance of the gases by to-the
changing the direction of the draught must be arranged considered permiss ble for.
In this construction a are the ordinary boiler-tubes, through which the furnace gases
after being utilized in the boiler, pass into the chimney. mare boiler-tubes of
greater diameter, through which pass the furnace gases serving for superheating
purposes. The superbeater in this construction is formed by two series of tubes o
n, communicating the one with the other at the top of the superheater. These
tubes on surround the chimney in form of a spiral; they are separated by a mantle p.
The gases steam coming from the boiler-tubes m, enters the inner superheating
spiral o at the bottom of-the-same. It and ascends the spiral to the top, whence they
there-arrived-it descends in the outer spiral mu and meets at the foot end of the
spiral the colder gases utilized within the boiler and passes together with the same
into the chimney.
and
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is
1. In tubular boilers, the division of heating gases, and the employment of the
hotter portion for superheating purposes, substantially and for the purpose as
described.
2. In tubular boilers, the combination of ordinary boiler-tubes a with a eireular
wall e having an opening regulable by means of flaps e, tubes a¹ consisting of
insulating material introduced in the boiler tubes enclosed by the mantle wall e,
steam pipes b and c, and superheating tubes & in spiral form connected to the steam
pipes and c, substantially and for the purpose as described.
3. In tubular boilers, the combination of fire-tubes a, with fire-tubes m of larger
diameter, two series on connected together at their top end, of superheating tubes
arranged in spiral form around the chimney, a mantle p separating these tubes to
nearly the top, substantially and for the purposo as described.
Dated this 6th day of July, 1899.
GEO. H. RAYNER,
Agent for the Applicant.