An Improved Boiler, principally for use on Steam Ships.
Year: 1892

page_text: Date of Application, 25th Aug., 1892-Accepted, 1st Oct., 1892
COMPLETE SPECIFICATION.
An Improved Boiler, principally for use on Steam Ships.
I, RUDOLF MÜLLER of Reiherstieg Hamburg 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 :-
This invention consists in a new or improved construction of boiler intended
principally for marine use. In the ordinary return tube marine boiler there is
below a flame tube or tubes within or in front of which is the fire box and in the
upper part of the boiler are the return flame tubes with which the first named are
in connection by a flue within the outer mantle or casing of the boiler, the boiler
therefore itself incloses both systems of tubes. In the improved boiler which is
the subject of the present invention, each of these tube systems, the lower flame
tubes and the upper return tubes is contained and comprised within a distinct and
separate boiler and these two boilers or distinct parts of the boiler are connected
as respects their fire tubes by a specially arranged flue or fire box with double
walls the water spaces of the two parts of the boiler communicating with each
other through and by means of the space between the two plates forming the
said double wall. Either of these parts may be duplicated.
This construction of boiler is very suitable for marine use since for equal heating
surface the boiler may be made to occupy a considerably smaller space than the
aforesaid marine boiler and by its construction it is also capable of being worked
at a higher pressure.
The invention is represented in the annexed drawings in which Fig. 1 is a side
elevation of the improved boiler. Fig. 2 is a cross section on line o o
Fig. 3.
Fig. 3 is a longitudinal section on line m m m m m Fig. 2. Fig. 4 is a cross
section on line Fig. 3 and Fig. 5 is a plan view or horizontal section on
line aaa Fig. 4.
a¹ and bare two flame tube systems and c¹ is a system of return tubes, each of
these systems being constructed in a distinct portion respectively a, b, c forming
in effect a distinct boiler. As shown in Fig. 2 a boiler of the old system having such
systems of tubes would have the shape shown by the dotted circle and the boiler
would take up a larger space in the ship. The flame tubes a b¹ may be made for
inside or for front firing, the latter being shown on the drawing. Front or outside
firing allows of each system consisting of a large number of tubes without
endangering the stability of the boiler. The back wall of each of the boilers a, b,
and is cut away or omitted at a² 62 and c respectively for connection of and
communication with the interior space of the double walls of the connecting flue B
which thus enclosed by a water jacket on all its sides as well as on the back, forms
an enclosed space for passage of the flames from the tubes a' and to the return
tubes call of which open into the space B. On the front of the flue B there
would be spaces t left open between the sides of the boilers a b and c and
between a c and the side double wall and between a band side double wall ƒ".
These spaces are filled with iron plates or fire brick. The boilers a and com-
municate respectively with the boiler c also through the orifices surrounded by the
flanges 9 by which means also the boilers a support the boiler c and form a solid
whole.
The supporting of the tubes in the back plates of separate boilers gives great
strength without necessitating staying such as is found in boilers of the usual kind;
since also the diameter of each boiler is considerably smaller than if the three were
combined in one the improved boiler will stand much higher pressure.
It will
also be seen from Fig. 2 that a reduction in the size of the boiler does not require

page_text: a reduction of the heating surface but only results in a reduction of the water
contents of the boiler.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed I declare that what I
claim is ;-
In a boiler the combination of the lower fire tubes and upper return fire tubes
cach, with a distinct boiler casing or with distinct casings substantially in the
manner described, the said casings being connected as to their water spaces with
the space between the double walls of the flue leading from the lower tubes to the
return tubes also substantially in the manner herein set forth.
Dated this 25th day of August 1892
HERBERT & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.