Improvements in Steam-generators of the Locomotive Boiler Type.
Year: 1895

page_text: Improvements in Steam-generators of the Locomotive Boiler Type.
I, WILHELM SCHMIDT, of Ballenstedt on the Harz, in the Duchy of Anhalt,
German Empire, Civil-engineer do hereby declare the nature of this invention to
be as follows:-
In steam generators of the locomotive boiler type, in which the heating surface
is in its greatest part formed by flame-tubes (fire-tubes, heating-tubes) there has up
to now not been attained an effective and at will, regulable superheating of the
quickly evolved wet steam.
Owing to their changing and oftentimes very severe work, locomotive-boilers
especially produce very wet steam, and their use is, therefore, in spite of their high
evaporating power a very uneconomical one. Furthermore the requisite quantity
of wet steam can, owing to the limited space, oftentimes be obtained only by an
excessive use of fuel, and with aid of a very strong artificial draught; but even
then said requisite quantity of wet steam can be generated during a short time only
as the direct heating surface is not in a favorable proportion to that offered by the
heating tubes.
All so-called superheaters as they have up to now become known with flame-tube
boilers of all kind have not in the least answered the expectatious. If devices of
said sort are arranged in the combusting-space, then this arrangement causes the
superheating bodies to get destroyed in short a time, and there is moreover no
possibility of effectively regulating the degree of superheating. If, on the other
hand, the superheater is arranged within the smoke-chamber, there is no possibility
of sufficiently exhausting the temperature of the waste-gases, which latter moreover
are far hotter than required for the superheating; in spite thereof there is hardly
a drying of the wet steam to be attained. Other drawbacks result finally from
narrowing the space of the fire-box or of the smoke-chamber by arranging the
superheater in either of said parts. Owing to all these reasons, flame-tube-boilers
have up to now not been able to produce large quantities of superheated steam.
The object of the present invention therefore is to make flame-tube-boilers
especially locomotive-boilers able:
1. To produce a very great quantity of wet steam on a very small space,
2. To superheat the whole quantity of said wet steam to any desired degree of
superheating.
3. To exhaust the heating gases as fully as possible,
4. To do away with the arising of sparks,
5. To separate sediments in a high degree, and to keep them off the important
parts of the boiler,
6. To keep. the packings of the flame- or fire-tubes within the four tube.
supporting-walls constantly tight, and to allow of an easy accessibility of
those parts of the boiler, that are most exposed to the hottest gases, as well
as of an easy exchange of the superheater or of one or the other part
thereof.
The aforesaid advantages which on being combined are able to increase to an
extraordinary extent the effect and the economy of boilers, especially of locomotive
and marine boilers, may be attained by the co-operation of the combinations and
гр

page_text: arrangements that are fully described hereinafter.
By making use of said
arrangements the recent water-tube-boilers with their numerous packings may well
be replaced by the simple flame-tube-boiler formerly employed.
In order to make my invention more clear, 1 refer to the accompanying
drawing, in which similar letters denote similar parts throughout the different
views, and in which:
Figure 1 is a longitudinal vertical section of my improved boiler;
Figure 2 is a vertical cross-section taken on line-8-9 of Figure 1;
form of
Figure 3 is another vertical cross-section taken on line 10-11 of Figure 1;
Figure is a vertical longitudinal section through a modified
construction;
Figure 5 is a vertical cross-section taken on line 12-13 of Figure 4,
Figure 6 is another vertical cross-section taken on line 14-15 of Figure 4, and
Figure 7 is a modification of a detail of either of said two boilers, which will
duly be referred to in the course of the following description.
That part of the boiler which contains the flame tube is divided into two
portions of different size; the rear-portion a, Figs. 1 & 2, contains generally the
shorter tubes whereas the front portion is generally provided with the longer
ones. In the form of construction shown in Figure 4 the rear portion a contains
only one large flame-tube which at the same time serves as a furnace.
The proportion of the lengths of the two sets of tubes in the front and rear
portion of the boiler depend first, upon the degree of superheating desired,
second, the quantity of wet steam to be generated, and third, the quantity of heat
remaining thereafter for the generation of steam within the portion 6 of the flame-
tube-boiler. To obtain the highest degree of superheating, the second set should
in general be as short as possible, and to exhaust the heating-gases as fully as
possible, the first set of tubes ought to be as long as possible.
Each of the said two portious a and b of the boiler is separated from the other by a
tube-supporting-wall w2 or 3, and both said walls are connected by (may be
isolated) walls so as firmly to connect the two portions of the boiler with each
other. The chamber d thus formed serves for the reception of a superheating-
device (, ); the close proximity of the wall-supporting-tubes w2 w3 is,
owing to the radiant heat taken up by said walls, and to the steam-forming power
of the same, of eminent importance for said superheater.
The connection of the water spaces and steam-spaces of the two boiler-portions a
and b is effected by means of a pipe or pipes. I prefer to arrange for this
purpose the pipe h which is situated outside the chamber d in the height of the
normal level of water.
The whole quantity of wei steam generated within the front and rear portion of
the boiler is led to the superheating device (s, c... .) by means of a connecting-
pipe o, and is led off in a superheated state by a collecting-pipe 6. The
superheating is regulated by means of a wide guide- and projection-piper,
& 4, which is able to lead a large part of the heating gases emanating from the
Figures I
tubes of the boiler portion a directly to the tubes of the boiler-portion b. By
wholly or partly closing said guide-pipe said gases may be compelled to
pass through between the superheating-body (*, . . .) before they arrive at the
tube-supporting-wall w 3.
C
If the steam generated is intended for motors especially constructed to be driven
by superheated steam, the superheating-chamber d should be separated from the
combustion-chamber only by very short flame-tubes, that the high superheating
intended may surely be obtained. It may in such a case happen, that the guide-
pipe r, if its wall is a solid one, commences to glow strongly, and is therefore liable
to get destroyed in a short time. To prevent this, I prefer to construct the guide-
and protection-pipe from a tube of considerably smaller diameter by bending that
tube so as to form thereof a hollow cylinder similar to r. The spiral thus formed
may well be used as a superheating-body and is formed into such a one by having
one of its ends connected to the collecting-pipe o, whereas the other end is

page_text: connected to the collecting-pipe o6, as indicated in Figure 7. The steam enters
the superheating spiral through the tube o' and leaves the latter in a superheated
state through the tube o G.
When employing short flame-tubes in the boiler-portion a, it is further necessary
to provide those portions of the wall-supporting-tubes w2 3, that are passed only
by steam, with suitably arranged protection-plates, which prevent said portions
from being too strongly acted on by the very hot furnace-gases, as well as by the
great heat radiated by the superheating coils sc.
When employing the novel arrangement hereinbefore in its main points described,
the exhaust of the heating-gases in the long tubes of the boiler part b may greatly
be increased by letting the feed-water enter the foremost portion of said part b, and
by dividing this part into a number of chambers by means of partition-walls.
In the form of construction shown in Figure 1 two partition-walls s¹ s 2 are used.
The feed-water is introduced into that chamber which is formed by the partition-
wall 2 and the tube-supporting-wall 4; said chamber is the coolest of the whole
boiler. The feed-water deposits the greatest part of its impurities within said
chamber, and flows without any violent motion over the upper edge of the
partition-wall 2 into the neighbouring chamber that is formed by said wall s 2 and
the partition-walls. The water whilst sinking down within this chamber loses
the remaining portion of its sediments.
The communication between the chamber last mentioned and that formed by the
partition-walls and the tube-supporting-wall 3 is at the bottom of the boiler.
The flow of the water into said third or last chamber occurs comparatively calm,
and there are nearly no impurities at all carried over into the boiler-part h.
The connection between the two boiler-parts is, as already stated, formed by the
pipe h.
Py causing the water to flow in a direction opposite to that of the
furnace-gases, there is obtained a very good exhaust of the furnace-gases, and
there are furthermore the portions situated next to the fire-box practically
perfectly secured against incrustation and the injurious consequences of the same.
The sediments deposited upon the bottom of the boiler-part 6. and, perhaps, also
in the connecting-pipe h, may be caught by special collectors, and from time to
time be led off by suitable cocks. There is no difficulty in doing this as the
sediments remain for long time in a muddy state.
As an incrustation of the tubes of the boiler-part cannot be prevented with
absolute perfection, and said incrustation might, perhaps, render the exchange of
the flame-tubes difficult. I prefer to manufacture the partition-walls 2 from
steel, and to provide their holes (through which the flame-tubes pass) with teeth or
equivalent projections adapted to scratch the incrustations off said tubes on
removing the latter from the boiler.
By depriving the water of by far the greatest portion of its impurities, and by
dividing the long flame-tubes into comparatively short ones by the intercalation of
the superheating-chamber. I very effectively prevent the packings of said tubes
from becoming untight.
If the superheater is arranged so as to be able to effect a very high superheating,
it may on heating the boiler, and during pauses of work, happen, that the super-
heater, which then is empty, or not passed by steam respectively, commences to
glow. To prevent this, there should be provided means allowing the greatest part
of the hottest gases to pass through the chamber without acting upon the
superheater. I obtain that purpose by letting that set of the heating-tubes, which
is arranged next to the furnace have a certain number of its tubes replaced by
other tubes having a larger diameter than the remaining ones. Said wider tubes
are preferably arranged directly opposite to the pipe r.
The superheater may, further. be protected against an injurious action of the
fire-gases by letting during pauses pass through said superheater that steam by
means of which the draught for the furnace is maintained.
To remove even the slightest possibility of a destruction of the superheating-
coils, I prefer to arrange them in a special way. I divide the superheater into a

page_text: number of parallel coils arranged in an upright position one behind the other, and
I let those spirals that are situated next to the furnace be formed by one coil
only whereas the other spirals are formed by two or more coils; and I further
connect said spirals with the steam-inlet and steam-outlet in such a manner that in
the spirals situated next to the furnace the steam flows from the inside to the
outside, whereas in all other spirals it flows from the outside to the inside.
By combining the arrangements just described I attain the advantage, that the
wettest steam is acted on by the hottest gases, and that the greatest heat of said
gases has already been broken, when the latter are allowed to act upon those
spirals, which consist of more than one coil, and within which the steam flows from
the outside to the inside, as afore stated. Said coils are thus fully prevented
from being burnt, and the steam flowing through them will not be superheated in
an excessive degree.
The novel arrangement described in the foregoing paragraphs affords, finally,
the important advantage, that sparks are perfectly hindered from entering the
smoke-chamber of the boiler; this is mainly attained by the action of the many
coils arranged within the chamber d. The particles of coal carried forth with the
furnace-gases push upon said coils, and are thus caused to fall upon the bottom of
said chamber, wherefrom they may be removed by any suitable means.
Dated this 9th day of December 1895
WILHELM SCHMIDT,
By Cassell & Co..
22, Glasshouse Street. Regent Street, London, W.,
Agents for the Applicant.
I, WILHELM SCHMIDT, of Ballenstedt on the Harz, in the Duchy of Anhalt,
German Empire, Civil-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 :-
In steam-generators of the locomotive boiler type in which the heating surface
is in its greatest part formed by flame-tubes (fire-tubes, heating-tubes,) there has
up to now not been attained an effective and at will regulable superheating of the
quickly evolved wet steam.
Owing to their changing and oftentimes very severe work locomotive-boilers
especially produce very wet steam, and their use is, therefore, in spite of their high
evaporating power a very uneconomical one. Furthermore, the requisite quantity
of wet steam can owing to the limited space oftentimes be obtained only by an
excessive use of fuel, and with aid of a very strong artificial draught, but even
then said requisite quantity of wet steam can be generated during a short time
only as the direct heating surface is not in a favorable proportion to that offered
by the heating tubes.
If
All so-called superheaters, as they have up to now become known with flame
tube boilers of all kinds, have not in the least answered the expectations.
devices of said sort are arranged in the combustion-space, then this arrangement
causes the superheating bodies to get destroyed in short a time, and there is more-
over no possibility of effectively regulating the degree of superheating. If, on the
other hand, the superheater is arranged within the smoke-chamber, there is no
possibility of sufficiently exhausting the temperature of the waste-gases, because
the superheater in consequence of the limited space cannot be so large as necessary
for a sufficient exhaustion of said gases. In other words, the superheater can be

page_text: but small, and there cannot thus be attained the degree of superheating desired.
In spite thereof, there is hardly a drying of the wet steam to be attained. Other
drawbacks result finally from narrowing the space of the fire-box or of the smoke-
chamber by arranging the superheater in either of said parts. Owing to all these
reasons flame-tube-boilers have up to now not been able to produce large quantities
of superheated steam.
The object of the present invention therefore is to make flame-tube-boilers,
especially locomotive-boilers, able:
1. To produce a very great quantity of wet steam on a very small space,
2. To superheat the whole quantity of said wet steam to any desired degree of
superheating;
3. To exhaust the heating gases as fully as possible.
4. To do away with the arising of sparks,
5. To separate sediments in a high degree and to keep them off the important
parts of the boiler, as well as of the superheater; the latter receives some-
times water that is torn away by the steam, and the superheater could
therefore get incrustated if the sediments were not completely removed from
the water;
6. To allow of an easy accessibility of those parts of the boiler, that are most
exposed to the hottest gases, as well as of an easy exchange of the super-
_heater, or of one or other part thereof, for which purpose the chamber
containing the superheater is made accessible by suitable covers or lids.
The aforesaid advantages which on being combined are able to increase to an
extraordinary extent the effect and the economy of boilers, especially of locomotive
and marine boilers, may be attained by the co-operation of the combinations and
arrangements that are fully described hereinafter. By making use of said
arrangements the recent water-tube-boilers with their numerous packings may
well be replaced by the simple flame-tube-boiler formerly employed.
In order to make my invention more clear. I refer to the drawing sent in with
Provisional Application, in which similar letters denote similar parts throughout
the different views, and in which:
Figure 1 is a longitudinal vertical section of my improved boiler.
Figure 2 is a vertical cross-section taken on line 8-9 of Figure 1.
Figure 3 is another vertical cross-section taken on line. 10-11 of Figure 1,
Figure 4 is a vertical longitudinal section through a modified form of
construction.
Figure 5 is a vertical cross-section taken on line 12-13 of Figure 4,
Figure 6 is another vertical cross-section taken on line 14-15 of Figure 4, and
Figure 7 is a modification of a detail of either of said two boilers, which will
dulv be referred to in the course of the following description.
That part of the boiler which contains the flame-tube is divided into two portions
of different size: the rear portion a, Figures 1 and 2. contains generally the shorter
tubes, whereas the front-portion is generally provided with the longer ones.
the form of construction shown in Figure 4 the rear portion a contains only one
large flame-tube which at the same time serves as a furnace.
In
The proportion of the lengths of the two sets of tubes in the front and rear
portion of the boiler depends, first, upon the degree of superheating desired,
second, the quantity of wet, steam to be generated, and, third, the quantity of heat
remaining thereafter for the generation of steam within the portion 6 of the flame-
tube-boiler. To obtain the highest degree of superheating, the second set should
in general be as short as possible. and to exhaust the heating-gases as fully as
possible, the first set of tubes ought to be as long as possible.
Each of said two portions a and b of the boiler is separated from the other by &
tube-supporting wall 2 or 3, and both said walls are connected by (may be
isolated) walls so as firmly to connect the two portions of the boiler with each
other. The chamber d thus formed serves for the reception of a superheating
device (s, e). Owing to the radiant heat taken up by the tube-supporting.

page_text: walls w2 3 and to the steam-forming power of the same the close proximity of
said walls is of eminent importance for said superheater.
The connection of the water-spaces and steam-spaces of the two boiler-portions a
and bis effected by means of a pipe or pipes. I prefer to arrange for this purpose
the pipe
which is situated outside the chamber in the height of the normal
level of water.
W
The whole quantity of wet steam generated within the front and rear portion of
the boiler is led to the superheating device (s, c...) by means of a connecting-
pipe o, and is led off in a superheated state by a collecting-pipe o 6. The super-
heating is regulated by means of a wide guide- and protection-piper. Figures 1
& 4, which is able to lead a large part of the heating gases emanating from the
tubes of the boiler portion directly to the tubes of the boiler-portion b. By
wholly or partly closing said guide-piper said gases may be compelled to pass
through between the superheating-body (s, c...) i.e. to wash intensely the
heating surfaces of the latter, before they arrive at the tube-supporting-wall : 3.
If the steam generated is intended for motors especially constructed to be driven
by superheated steam the superheating-chamber d should be separated from the
combustion-chamber only by very short flame-tubes, that the high superheating
intended may surely be obtained. It may in such a case happen, that the guide-
pipe r if its wall is a solid one, commences strongly to glow, and is therefore liable
to get destroyed in a short time. To prevent this. I prefer to construct the guide-
and protection-pipe from a tube of considerably smaller diameter by bending
that tube so as to form thereof a hollow cylinder similar to r. The spiral thus
formed may well be used as a superheating-body, and is formed into such a one by
having one of its ends connected to the collecting-pipe o', whereas the other end is
connected to the collecting-pipe o 6, as indicated in Figure 7. The steam enters
the superheating spiral through the tube o¹ and leaves the latter in a superheated
state through the tube o 6.
When employing short flame-tubes in the boiler-portion a, it is further necessary
to provide those portions of the fube-supporting-walls w 2 3 that are washed only
by steam with suitably arranged protection plates, which prevent said portions
from being too strongly acted on by the very hot furnace-gases, as well as by the
great heat radiated by the superheating coils sc.
When employing the novel arrangement herein before in its main points
described, the exhaustion of the heating-gases in the long tubes of the boiler part b
may greatly be increased by letting the feed-water enter the foremost portion of
said part b, and by dividing this part into a number of chambers by means of
partition-walls.
In the form of construction shown in Figure 1 two partition-walls ss2 are used.
The feed-water is introduced into that chamber, which is formed by the partition-
wall s 2 and the wall-supporting-tube 4; said chamber is the coolest of the whole
boiler. The feed-water deposits the greatest part of its impurities within said
chamber, and flows without any violent motion over the upper edge of the partition-
wall 2 into the neighbouring chamber that is formed by said wall 2 and the
partition-walls. The water whilst sinking down within this chamber looses the
remaining portion of its sediments.
The communication between the chamber last mentioned and that formed by
the partition-walls and the wall-supporting-tube 3 is at the bottom of the
boiler. The flow of the water into said third or last chamber occurs comparatively
calm, and there are nearly no impurities at all carried over into the boiler-part a.
The connection between the two boiler-parts is, as already stated, formed by the
pipe h. By causing the water to flow in a direction opposite to that of the furnace
gases, there is obtained a very good exhaustion of the furnace-gases, and there are
furthermore the portions situated next to the fire-box practically perfectly secured
against incrustation and the injurious consequences of the same.
The sediments deposited upon the bottom of the boiler-part 6, and, perhaps, also
in the connecting-pipe 1, may be caught up by special collectors, and may be led

page_text: off from time to time by suitable cocks. There is no difficulty in doing this, as the
sediments remain for long time in a muddy state.
As an incrustation of the tubes of the boiler-part a cannot be prevented with
absolute perfection, and said incrustation might, perhaps, render the exchange of
the flame-tubes difficult, I prefer to manufacture the partition-walls ss2 from
steel, and to provide their holes (through which the flame-tubes pass) with teeth or
equivalent projections adapted to scratch the incrustations of said tubes on
removing the latter from the boiler.
By depriving the water of by far the greatest portion of its impurities, and by
dividing the long flame-tubes into comparatively short ones by the intercalation of
the superheating-chamber, I very effectively prevent the packings of said tubes
from becoming untight.
If the superheater is arranged so as to be able to effect a very high super-
heating, it may on heating the boiler, and during pauses of work, happen, that the
superheater, which then is empty, or not passed by steam respectively, commences
to glow. To prevent this, there should be provided means allowing the greatest
part of the hottest gases to pass through the chamber d without acting upon the
superheater. I obtain that purpose by letting that set of the heating-tubes which
is arranged next to the furnace have a certain number of its tubes replaced by
other tubes having a larger diameter than the remaining ones. Said wider tubes
are preferably arranged directly opposite to the pipe r.
The superheater may, further, be protected against an injurious action of the
fire-gases by letting during pauses pass through said superheater that steam by
means of which the draught for the furnace is maintained.
To remove even the slightest possibility of a destruction of the superheating-
coils, I prefer to arrange them in a special way. I divide the superheater into a
number of parallel coils arranged in an upright position one behind the other, and
I let those spirals that are situated next to the furnace be formed by one coil only,
whereas the other spirals are formed by two or more coils; and I further connect
said spirals with the steam-inlet and steam-outlet in such a manner that in the
spirals situated next to the furnace the steam flows from the inside to the outside,
whereas in all other spirals it flows from the outside to the inside. By combining
the arrangements just described I attain the advantage, that the wettest steam is
acted on by the hottest gases, and that the greatest heat of said gases has already
been broken, when the latter are allowed to act upon those spirals, which consist
of more than one coil, and within which the steam flows from the outside to the
inside, as afore stated. Said coils are thus fully prevented from being burnt,
and the steam flowing through them will not be superheated in an excessive
degree.
The novel arrangement described in the foregoing paragraphs affords, finally,
the important advantage, that sparks are perfectly hindered from entering the
smoke-chamber of the boiler; this is mainly attained by the action of the many
coils arranged within the chamber d. The particles of coal carried forth with the
furnace-gases push upon said coils, and are thus caused to fall upon the bottom of
said chamber, wherefrom they may be removed by any suitable means.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I .
claim is:-
1. A steam-generator of the locomotive-boiler-type having a superheater, and
being characterized by the latter being arranged within a chamber, which divides
the boiler proper as well as its heating tubes into two parts, and the interior of
which is accessible from the outside of the boiler; said superheater being shaped.
and arranged within said chamber, in such a manner, that it may be more or less
exposed to the action of the fire-gases by aid of a regulating-device.
2. A form of construction of the steam-generator characterized by Claim 1, in

page_text: a
which on commencing heating the boiler, and during pauses of work, the super-
heater is protected against too strong an action of the fire-gases by those heating-
tubes of the rear part of the boiler that lie opposite to the guide-pipe (r) having
larger diameter than the rest, so that on said guide-pipe being opened the greatest
part of the fire-gases is diverted from the superheater, and is used for an increased
generation of steam within the front-part (b) of the boiler.
3. A form of construction of the steam-generator characterized by Claim 1, in
which the superheater is prevented against incrustation, and at the same time the
front-part of the boiler is enabled to draw more heat from the fire-gases
steaming through its heating-tubes that can be drawn by the intercalation of the
superheating-chamber alone, by causing the water to ascend and descend between
partition-walls (2 and s) and to deposit its sediments during said time; said
water entering the boiler at the coolest end of the part b.
Dated this 9th day of September 1896.
WILHELM SCHMIDT,
By Cassell & Co.,
22 Glasshouse Street, Regent Street, London,
Agents for the Applicant.
WILHELM SCHMIDT.
By Cassell & Co.,
22 Glasshouse Street, Regent Street, London,
Agents for the Applicant.