Improvements in Multitubular Steam Boilers.
Year: 1891

page_text: Date of Application, 16th Apr., 1891-Accepted, 16th May, 1891
COMPLETE SPECIFICATION.
Improvements in Multitubular Steam Boilers.
1, MAX GEHRE of Rath near Dusseldorf 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:-
In multitubular steam boilers as hitherto constructed where the water is inside
the tubes the steam generated therein fills the upper portion of each tube and
where much steam is generated in proportion to the capacity of the tube it will be
in contact with a proportionately large part of the heating surface of the tube, and
consequently the water will be prevented from reaching that part of the heating
surface of the tube whereby two losses result. First the production of steam is
reduced, and second those parts of the tube are liable to be burned.
To remedy these drawbacks the present invention has been devised and it will be
best understood by reference to the accompanying drawings in which
Figure 1 is a longitudinal section of a boiler adapted for carrying out the present
invention and
Figures 2 and 3 are cross sections of two tubes which will illustrate the
invention.
Figure 4 is an end view of Figure I showing the limb D and cylindrical portion E
in section.
The boiler selected to illustrate the invention is of that type comprising a
horizontal shell C intended to be half filled with water and set in masonry or a
metal casing and having projecting limbs or legs D between which the tubes a to
which the invention is applied extend the said tubes containing the water and being
surrounded by the fire.
In each tube a is a longitudinal deflector or diaphragm & which extends through-
out the length of the tube both of the compartments thus formed in the tube being
open at each end. By this arrangement the steam bubbles rising from the lower
part of the tube are intercepted by the diaphragms and prevented from rising to
the upper part of the tube being conducted by the diaphragm to the end of the
tube and there escaping in the usual manner. The water again contained in the
upper part of the tube that is the space between the upper wall of the tube and
the diaphragm will of course also produce steam but as that will be relatively a
small quantity the space occupied by the steam against the wall of the tube will
be very small in proportion to the total heating surface of the tube and con-
sequently the drawbacks enumerated at the commencement of the Specification are
to a very large extent got over by the adoption of this invention. In Figures 2
and 3 the supposed spaces occupied by the steam are indicated at b' and a¹.
In Figures 2 and 3 two forms of diaphragm are shown; in Fig. 2 a curved strip
of metal is indicated while in Fig. 3 two flat pieces meeting at an angle or one flat
piece bent to the angle are indicated, but it will be understood that the precise
shape or construction of the diaphragm is comparatively immaterial and may be
varied according to circumstances. It might for example be corrugated longi-
tudinally and thus provide a number of channels along which the steam bubbles
could travel. The diaphragm may be fixed to the tube or may be merely loosely
placed therein.
To facilitate the free and unimpeded transmission of the steam into the upper
boiler C the front limb or water chamber D which receives the steam takes a
cylindrical shape at its upper portion as indicated at E in Figures 1 and 4 of the
drawings the parts I being left open for the passage of the steam or water. Also
an extension of the limb D may with advantage be provided taking the form of

page_text: a flat tube with its upper part G removed so as to carry the steam above the level
of the water and deliver it into the cylindrical tube E from which it would pass by
the opening F into the boiler C.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed declare that what I
claim is
1. The combination with the tube of a steam boiler of a longitudinal deflector or
diaphragm such as & substantially as and for the purpose described and illustrated
in the accompanying drawings.
2. In a multitubular steam boiler the employment of tubes a having longitudinal
deflectors or diaphragms such as substantially as and for the purpose described
and illustrated in the accompanying drawings.
3. In a multitubular steam boiler a flat limb or leg such as D adapted to receive
the water tubes and assuming a cylindrical shape such as E at its upper part sub-
stantially as described and illustrated in the accompanying drawings.
Dated this 16th day of April 1891.
W. P. THOMPSON & BOULT,
Agents for the Applicant.