Improvements in Steam Generators.
Year: 1894

page_text: Date of Application, 20th Jan., 1894
Complete Specification Left, 18th Oct., 1894--Accepted, 24th Nov., 1894
Improvements in Steam Generators.
I, RICHARD SCHULZ of Tegel near Berlin in the Empire of Germany, Engineer,
do hereby declare the nature of this invention to be as follows:-
:-
The steam boiler which forms the object of this invention has various advantages
over the forms of boiler construction of Thornycroft, Yarrow, Normand, Du Temple,
and others at present employed.
This improved boiler is suitable for the highest steam pressures which can be
practically employed (20 to 30 atmospheres) and especially for producing dry and
even superheated steam, whilst at the same time it allows of the system of tubes
being conveniently and effectively cleaned.
It consists in general of a cylindrical upper boiler and two cylindrical under
boilers, between which latter the grate is arranged and which are connected
with the upper boiler by a number of small. water tubes. These water tubes are
curved in the well known manner in order to allow of the bending arising from the
extent to which the firing is forced being followed to the best advantage, without
the joints at the tube ends being thereby affected. Whilst, however, in the steam
boilers of this kind hitherto employed, the water tubes either all open into the
steam space, or all into the water space of the upper boiler, in this improved boiler,
part of the water tubes open into the steam space and the remainder into the water
space of the upper boiler.
The water tubes are arranged side by side in several rows, so that everywhere
as even a distance as possible remains between the tubes, in order to allow of the
tubes being cleaned. The cleaning of the tubes takes place from the front of the
boiler when the doors, arranged there for this object, have been removed.
The water tubes are so arranged that the inner row of tubes and the outer row
of tubes form closed walls, openings being provided in the inner wall for admitting
the furnace gases, and in the outer wall for the escape of the furnace gases.
The formation of the wall by means of the pipes may be done in various ways.
The tubes of the cuter and inner row may, for instance, have a larger diameter
than the remainder of the tubes, so that their sides come mutually in contact, or
they may be of an oval section and be in contact one with another at their
narrowest end.
The openings for the inlet and outlet of the furnace gases may also be made in
various ways. The lower ends of the inner row of tubes or the upper ends of the
outer row of tubes may, for instance, be of smaller diameter than the remaining
part of the tubes, or they may also be of an oval section. In this latter case,
however, the longitudinal axes must stand vertically to the wall.
The result of both patterns is that interstices are formed between the separate
pipes at the lower or upper ends, through which interstices the furnaces may pass
in and out.
In order to free the steam produced in the water tubes from the water contained
in it, two vertical sheet metal plates are arranged in the upper boiler in front of the
openings of the water tubes, which plates extend from the steam space into the
water space, and which remain with their upper and lower edges at a suitable
distance from the inner wall of the boiler, whilst the side edges are bent at right
angles and fit close to the inner wall. The mingled steam and water coming from
the tubes encounters these plates, by which means the water is directed downwards
whilst the steam escapes upwards. In this manner, a steady water level between

page_text: the plates is attained, whilst simultaneously a regulated flow of the water through
the whole length of the upper boiler to the connecting tubes arranged at the rear
end thereof and the two under boilers is brought about. As these connecting tubes
are arranged at the rear side of the boiler, they do not hinder the cleaning of the
water tubes in any way.
The well known tubular boilers of Thornycroft, Yarrow, Du Temple, Normand,
and others, can only produce dry steam up to a certain degree of pressure, but in
no case superheated steam, which, if used in moderation, assists enormously in a
sure and economical working. In order to be ready for all circumstances, super-
heating tubes are arranged in this improved boiler, in such a way that, either the
whole of the steam developed or only a part thereof may be conveyed through these
superheaters.
The superheater is placed above the actual steam boiler in the uppermost part of
the smoke box through which the heating gases escape to the chimney. The heat
which is otherwise lost is thus here utilised to a certain extent without any further
cost of working.
The superheater consists essentially of two large tubes arranged in the smoke
box and lying parallel to the upper boiler, which tubes are connected with one
another by means of a number of smaller tubes which may be arranged in one or more
rows. The steam accumulated in the upper boiler, passes first into the cross tube
lying in front of the boiler, flows from this into the first superheating tube, from
the latter through the smaller tubes into the second large superheating tube and
from here into the steam pipe. A stop valve is arranged in the cross pipe between
the steam accumulator or upper boiler and each of the superheating pipes.
Accordingly, as these valves are opened more or less, only a suitable amount of the
boiler steam is passed into the superheater, whilst the remainder on the other hand
passes directly into the steam pipe. It is thus possible to bring the steam to the
most suitable temperature by means of a mixture of superheated and damp steam.
If desired, the valve between the steam accumulator and the first tube of the
superheater may be omitted.
A row of smoke arresting valves or dampers is arranged in the smoke box above
or beneath the smaller superheating tubes in order that the draught of the heated
gases may be regulated thereby more particularly so that when forced draught is
employed, the heated gases may not be carried off too quickly to the chimney but
may impart their temperature more effectively to the heating surfaces of the
boiler.
Dated this 19th day of January 1804
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
I, RICHARD SCHULZ of Tegel near Berlin in the Empire of Germany 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:-
The steam boiler which forms the object of this invention has various advantages
over the forms of boiler construction of "Thornycroft, Yarrow, Normand, Du Temple,
and others at present employed.
This improved boiler is suitable for the highest steam pressures which can be
practically employed (20 to 30 atmospheres) and especially for producing dry and
even superheated steam, whilst at the same time it allows of the system of tubes
being conveniently and effectively cleaned.

page_text: Figure 4 a plan of the boiler from above;
Figures 5, 5 and 5° cross section to a larger scale of the water tubes on the
line - of Figure 2;
Figures 64, 6 and 6° a similar cross section on the line of Figure 2;
Figure 7 a cross section of another form of the water tubes;
Figure 8 a vertical cross section of a boiler with one upper and three under
boilers;
Figure 9 shows a similar boiler with another arrangement of the water walls;
Figure 10 shows a similar boiler with special water walls inside the group of
tubes;
Figure 11 shows the invention applied to a boiler fired from both ends.
It consists in general of a cylindrical upper boiler and two cylindrical under
boilers a, between which latter the grate is arranged and which are connected with
the upper boiler by a number of small water tubes c. These water tubes are curved
in the well known manner in order to allow of the bending arising from the extent
to which the firing is forced being followed to the best advantage, without the
joints at the tube ends being thereby affected. Whilst, however, in the steam
boilers of this kind hitherto employed, the water tubes either all open into the
steam space, or all into the water space of the upper boiler, in this improved boiler,
part of the water tubes open into the steam space and the remainder into the water
space of the upper boiler.
The water tubes are arranged side by side in several rows, so that everywhere as
even a distance as possible remains between the tubes, in order to allow of the tubes
being cleaned. The cleaning of the tubes takes place from the front of the boiler
when the doors, arranged there for this object, have been removed.
The water tubes c are so arranged that the inner row of tubes c' and the outer
row of tubes e form closed walls, openings being provided at in the inner wall e¹
for admitting the furnace gases, and in the outer wall for the escape of the
furnace gases.
The formation of the wall by means of the pipes may be done in various ways.
The tubes of the outer and inner row may, for instance, as shown in Figure 64,
have a larger diameter than the remainder of the tubes, so that their sides come
mutually in contact, or they may be of an oval section as shown in Figure 6" and
be in contact one with another at their narrowest end.
The openings .e and y for the inlet and outlet of the furnace gases may also be
made in various ways.
The lower ends of the inner row of tubes c¹ or the upper
ends of the outer row of tubes c² may, for instance, as shown in Figures 5 and 5B,
be of smaller diameter than the remaining part of the tubes, or they may also be of
an oval section as shown in Figure 5°. In this latter case, however, the longitudinal
axes must stand vertically to the wall.
The result of both patterns is that interstices are formed between the separate
pipes cor c² at the lower or upper ends, through which interstices the furnace
gases may pass in and out.
The water walls may also, as shown in Figure 7, be formed by providing the
tubes c with side ridges h which fit closely together at the places where they are to
form a wall. These ridges are omitted at the places where the furnace gases are to
pass between the tubes.
The advantage of such tubes is that they have a greater surface in contact with
the fire than cylindrical tubes of equal diameter, they will therefore convey the heat
more quickly even whilst containing an equal quantity of water and thus have a
greater evaporating power. The ridges inay be of various dimensions and shapes
on the ordinary cylindrical form of the tubes, but oval tubes may also be provided
with similar ridges. It is preferable in the case of large boilers with considerable

page_text: heating and grate surface to make use of one upper boiler and three under boilers
and two separate grates.
Figures 8-10 show in the accompanying drawings various forms of arrangement
of such a boiler.
The groups of tubes connecting the three under boilers a a¹ with the upper
boiler are so arranged that the middle under boiler a' has two groups of tubes
each of which contains about as many tubes as there are in the groups of tubes
proceeding from the two outer under boilers a.
The two middle groups of tubes connect with the steam space or the water space,
the two outer ones with the steam space.
The water walls may be arranged in various ways.
In the outer groups of tubes, the furnace gases pass in through interstices a and
out through interstices y, whilst in the middle groups of tubes they pass in through
the interstices and out through the interstices y'. These inlets and outlets
may be arranged in the upper or lower part of the water walls, as may be seen in
Figures 8 and 9.
In the arrangement shown in Figure 10 special water walls are
also arranged in the centre of the group of tubes, so that the furnace gases are
conducted through a lengthy course through the group of tubes.
If special circumstances render it preferable, the interstices in the water walls
for the passage of the furnace gases may be arranged otherwise than in rows above
and below.
Figure 11 shows a steam boiler which is fired from both ends. In this case the
arrangement of the groups of tubes is the same as in the other cases.
in
In order to free the steam produced in the water tubes c from the water contained
in it, two vertical sheet metal plates d e f g are arranged in the upper boiler
front of the openings of the water tubes, which plates extend from the steam space
into the water space, and which remain with their upper and lower edges at a
suitable distance from the inner wall of the boiler, whilst the side edges d e and f g
are bent at right angles and fit close to the inner wall. The mingled steam and
water coming from the tubes c encounters these plates, by which means the water is
directed downwards whilst the steam escapes upwards. In this manner, a steady
water level between the plates is attained, whilst simultaneously a regulated flow of
the water through the whole length of the upper boiler to the connecting tubes h h
arranged at the rear end thereof and the two under boilers is brought about. As
these connecting tubes are arranged at the rear end of the boiler, they do not
hinder the cleaning of the water tubes c in any way.
The well known tubular boilers of Thornycroft, Yarrow, Du Temple, Normand,
and others, can only produce dry steam up to a certain degree of pressure, but in
no case superheated steam, which, if used in moderation, assists enormously in a
sure and economical working. In order to be ready for all circumstances, super-
heating tubes are arranged in this improved boiler, in such a way that, either the
whole of the steam developed or only a part thereof may be conveyed through
these superheaters.
The superheater is placed above the actual steam boiler in the uppermost part
of the smoke box through which the beating gases escape to the chimney. The
heat which is otherwise lost is thus here utilised to a certain extent without any
further cost of working.
The superheater consists essentially of two, large tubes and ; arranged in the
smoke box and lying parallel to the upper boiler, which tubes are connected with
one another by means of a number of smaller tubes k which may be arranged in one
or more rows. The steam accumulated in the upper boiler b, passes first into the
cross tube lying in front of the boiler, flows from this into the first superheating
tube i, from the latter through the smaller tubes k into the second large super-
heating tube; and from here into the steam pipe. Stop valves m and n are
arranged in the cross pipe between the steam accumulator or upper boiler band
each of the superheating pipes i and j. Accordingly, as these valves are opened
or less, only a suitable amount of the boiler steam is passed into the
more

page_text: superheater whilst the remainder on the other hand passes directly into the steam
pipe. It is thus possible to bring the steam to the most suitable temperature by means
of a mixture of superheated and damp steam. If desired, the valve n between the
steam accumulator and the first tube of the superheater may be omitted.
A row of smoke arresting valves or dampers o is arranged in the smoke box
above or beneath the superheating tubes k in order that the draught of the heated
gases may be regulated thereby, more particularly so that when forced draught is
employed, the heated gases may not be carried off too quickly to the chimney but
may impart their temperature more effectively to the heating surfaces of the
boiler.
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. A water tube boiler or steam generator in which for the purpose of forming
water walls the tubes of the inner and outer rows of curved tubes connecting the
upper and lower boilers are widened for a part of their length, or provided with
side ridges in such a way that they touch one another, whilst long interstices are
formed at the under or upper ends of the said rows of tubes between the parts of
the tubes which are not expanded or are not provided with ridges, through which
interstices the furnace gases pass in or out, substantially as described and
illustrated.
2. A water tube boiler of the kind described in Claim 1, having one upper
boiler b and three under boilers a a', and two groups of tubes connecting with the
middle under boiler a¹ each of which groups of tubes contains about as many tubes
as there are in the groups of tubes connecting with the two outer under boilers a,
substantially as described and illustrated.
3. A water tube boiler of the kind described in Claim 1, having partitions for
forming smoke ways arranged between the inner and outer walls and produced in a
similar way to the latter, substantially as and for the purpose described and
illustrated.
4. A. water tube boiler of the kind described in Claim 1, having metal plates
arranged partly in the steain space and partly in the water space of the upper
boiler parallel to its longitudinal axis, which plates are inclined obliquely down-
wards in order to produce a steady water level and obtain a regular flow of the
water through the whole length of the upper boiler, substantially as described and
illustrated.
5. In a water tube boiler of the kind described in Claim 1, a superheater consisting
of tubes ij arranged in the smoke box which tubes are connected with one another by
several small tubes, and communicate with the steam accumulator in such a way
that the whole of the steam produced or only a portion of the same may be
conveyed through the superheater, substantially as described and illustrated.
Dated this 17th day of October 1894.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.