Improvements in Water Tube Boilers.
Year: 1892

page_text: Date of Application, 5th Dec., 1892-Accepted, 7th Jan., 1893
COMPLETE SPECIFICATION.
[Communicated from abroad by LOUIS MARIE GABRIEL DELAUNAY-BELLEVILLE,
of 40ter, Rue de Douai, Paris, France, Engineer.]
Improvements in Water Tube Boilers.
I, ERNEST DE PASS, of 78, Fleet Street, in the City of London, Fellow of the
Chartered Institute of Patent Agents, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement, reference being had to the
accompanying drawings and to the letters and figures marked thereon, that is
to say :-
This invention relates to an improvement in the arrangement of the water tubes
of tubulous boilers, the said improvement consisting in the progressive or sectional
division of the inclination of the tubes, whose succession forms a steam generating
element, or section; so as to give the greatest inclination to the lower tubes and
the least inclination to the upper ones.
In serpentines with uniform inclination, and especially for the double sections
of the Belleville system, the inclination of the tubes, for a given length of the
generating sections, is determined by the vertical distance of the axes of the con-
secutive headers, and this distance is uniform throughout the development of the
serpentine or section.
If the length of the sections be increased without the height of the headers
being changed, the inclination of the tubes decreases. Now in proportion to the
increase of the heating surface which results from the lengthening of the sections,
the vaporization of these tubes is greater, and the steam produced must, to
disengage itself, displace a much larger quantity of water, and undergo, in pro-
portion to its longer travel, a greater friction. Consequently, it is necessary to all
the more favour the disengagement of the steam by an increase in the inclination
of the lower tubes, as the length of these sections is more considerable.
The carrying out of this greater inclination necessitates a greater vertical
separation of the headers, and, when it is applied to the whole of the spires of the
section, therefore considerably increases the height of the generator, which con-
stitutes a serious inconvenience in certain cases, as in marine applications where
the height of the compartments reserved for boilers is strictly limited.
Therefore, with sections of uniform inclinations, there is, on the one hand, the
inconvenience of excessive height, and, on the other, that of a too slight inclination
of the tubes, thus entailing defective working. But it must be observed that, in
proportion as the spires more remote from the fire are taken into consideration,
these spires contain comparatively a larger quantity of steam and a lesser quantity
of water, the steam has therefore so much the more facility for disengagement,
and the inclination of the tube is so much the less necessary.
The upper spires of the section may even be compared to a steam conduit which
may, with impunity, run horizontally or descend, or form a turn or bend, etc. It is
therefore reasonable that the inclination of the tubes should go on diminishing
from the lower tubes whose inclination is that which is judged suitable for the best
working of generators, to the upper tubes, whose inclination is that which results
from the minimum pitch of the spire determined by the conditions of practical
construction.
Under these conditions the total height of the spire, or of the section, is con-
siderably less than if the inclination considered as suitable for the tubes most
heated was maintained throughout the development of the spire, and, at the same
time, the inclinations have at each point a valve favourable to the good working
of the apparatus.

page_text: To simplify the construction the section can be built up in two or three superposed
portions, each portion being individually composed of tubes of uniform inclination,
but this inclination being so much. the less as the portion considered occupies a
more elevated position in the section.
The facility of increasing the inclination of the lower tubes of the sections
without increasing excessively the height of these elements, is very advantageous
in cases of forced working and allows of the limit of the maximum vaporization
compatible with the safety of working of the apparatus being extended.
And in order that my invention may be more readily understood, I will describe
the same fully with reference to the accompanying drawings in which the same
letters indicate similar parts.
Fig. 1. represents the geometric outline of a section or serpentine of a boiler
with inclined tubes in which the inclinations of the tubes follow, from spire to
spire, a decreasing progression from the base to the summit.
Fig. 2 represents the geometric outline of a section or serpentine formed by a
succession of spires or inclined tubes in which the tubes of the three lower spires
have sharp inclinations while the tubes of the spires above have minimum inclina-
tion necessary for the requirements of practice and especially for the passage of
the cleaning brushes between the headers.
Fig. 3 shows the section constructed according to the geometric outline of
Fig. 2.
The complete element or section shown in Fig. 2, is composed of a first series
of lower spires G, more inclined than the six upper spires H, whose inclination
approaches the horizontal. The spires forming the section start from the lower
front header A, and the sharply inclined spires are connected at back by the
headers C, and in front by the headers B. The tubes H of the upper portion
of the section are connected together by the back headers E and the front
headers D to finish at the outlet elbow F.
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 1
claim is :-
1. The application of different and progressive inclinations to the tubes of steam
generators, formed serpentine-wise, and especially to the tubes of the sections of
Belleville's system, the inclination of the tubes being capable of decreasing
regularly from the base of the section to its top; the tubular cluster forming the
section being capable also of division into two or more portions for each one of
which the inclination of the tubes is constant and less than that of the portion
immediately below, substantially as set forth.
2. The improved section or element for tubulous boilers in which the water tubes
are arranged in the manner substantially as described and shown with reference to
Fig. 3 of the annexed drawings.
Dated this 5th day of December 1892.