Improvements in Bollers or Steam Generators.
Year: 1894

page_text: Date of Application, 11th Sept., 1894-Accepted, 1st Dec., 1894
COMPLETE SPECIFICATION.
Improvements in Bollers or Steam Generators.
I, CHARLES DELL MOSHER, of 1 Broadway New York City, in the County and
State of New York, United States of America, Gentleman, 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 relates to a boiler or steam generator comprising an elevated
steam drum and a plurality of water drums located below the steam drum and
each connected thereto by a series of tubes which are exposed to heat from a
fire box.
The invention has for its object to provide a boiler or steam generator of
this type, which shall be of compact and simple construction and in which the
drum-connecting tubes shall be straight, so that they can be readily inspected and
cleaned.
The invention also has for its object to provide such a construction as will enable
any tube of the series to be readily removed and replaced by another without
disturbance of the adjacent tubes.
To these ends the invention consists in the improvements which I will now
proceed to describe and claim.
Of the accompanying "drawings forming a part of this Specification,
Figure 1 represents a longitudinal section of a steam boiler or generator provided
with my improvements.
Figure 2 represents a section on line 2-2 of Figure 1.
Figure 3 represents a modification.
Figure 4 represents a transverse section showing a boiler embodying my
improvements, and a portion of the hull of a vessel.
Figure 5 represents a partial sectional view and partial side elevation of a boiler
embodying my invention.
Figure 6 represents an elevation of a portion of the boiler shown in Figure 5.
Figure 7 represents a transverse section of a portion of the hull of a vessel.
showing two of my improved boilers, one of said boilers being shown in
section.
The same letters of reference indicate the same parts in all the figures.
In the drawings-
transverse
a represents the steam drum, and 6 6 the water drums of my improved generator.
Each water drum is connected with the steam drum by a series of straight tubes c,
the ends of which are expanded in holes formed for their reception in said "drums.
Each water drum is flattened or reduced at the side adjacent to the steam drum,
said reduced side constituting a tube sheet 2 which is preferably arched, so that
it has the same curvature as the corresponding surface of the steam drum. The
water drum thus formed may be made of two parts riveted permanently together,
or it may be made by flattening or reducing one side of a lap-welded tube, it being
desirable in all cases to give the water drum a semi-cylindrical side 3 for the sake
of strength and a tube sheet 2 having a surface of practically the full width of the
drum, which is available for the reception of tubes, so that the series of tubes can
extend entirely across each water drum, this arrangement enabling the maximum.
number of tubes to be used with the minimum width or diameter of water drum,
hence the generator as a whole is given a compact form.
I do not limit myself to giving the tube sheet portions of the water drums an
arched form. as said portions may be made flat, as shown in Figure 3.

page_text: The steam drum is made of an internal diameter somewhat greater than the
length of the longest tubes c, so that each tube can be inserted in the holes formed
for its reception in the two drums, by a workman within the steam drum, the
relation of the length of the tubes to the diameter of the steam drum enabling
the workman to pass the tubes outwardly from within the drum, through the holes
therein. The distance between each water drum and the steam drum corresponds
to the length of the tubes.
It will be seen that the described form of the water drums, in connection with
the diameter of the steam drum relatively to the length of the tubes enables each
water drum to be connected with the steam drum by the largest number of straight
tubes that is possible with a given diameter of water drum. The tubes, being
straight, can be readily inspected and cleaned, and any worn or defective tube can
be readily removed and replaced by a new one, by a workman 'within the steam
drum.
The described relation between the diameter of the steam drum and the length
of the tubes also enables the walls of the steam drum to be made of the minimum
thickness and weight, and without packed joints. If the steam drum were of less
diameter, it would be necessary to provide for the removal of a part or parts of
the drum to enable the insertion and removal of tubes, so that the drum would
have to be made either in sections, its upper half being separable from the lower,
or would have to be provided with numerous hand-holes in its upper portion at
points opposite the tubes. In either case the walls of the steam drum would have
to be made much thicker and heavier, to compensate for the weakening occasioned
by the sectional or separable construction, and packed joints would be required.
Packed joints in a steam boiler are always a source of weakness, and are to be
avoided if possible, particularly in large sized boilers, where the working strains
are necessarily great.
It will be seen that by making the steam drum of the described diameter
relatively to the length of the tubes, I avoid any sectional construction requiring
packed joints, and am enabled to utilize any desired portion of the periphery of
the steam drum as a tube sheet to receive the upper ends of the tubes.
In
My present improvements relate chiefly to marime boilers. I have shown
various forms of this type of boiler adapted for different sizes and classes of steam
vessels or other purposes, all embodying the features above described.
Figures 1 and 2, I show two water drums located at opposite sides of a single
fire-box e; a casing communicating at its upper portion with a smoke-stack,
encloses the parts of the boiler above the water drums, and receives the products
of combustion after they have passed between the tubes. I prefer to provide
baffle-plates 99 extending downwardly from the sides of the steam drum partly to
the lower ends of the tubes, for the purpose of directing the gases, etc., downwardly
after they have passed between the upper portions of the tubes, so that they will
act on the cooler lower portions of the tubes before escaping to the stack.
oo 'represent return pipes which connect the steam drum with the water drums,
said return pipes being shown in dotted lines in Figure 2.
.
In Figures 4, 5, and 6, I show a construction which includes five water drums,
which with the connecting tubes are radially arranged and are separated by four
fire-boxes e. The water drums are arranged on a curve conforming approximately
to the cross-section of the hull. Said water drums are supported by saddles i
formed on or attached to the upper edges of vertical foundation plates which are
suitably secured, as by angle-bars to the hull of the vessel. The plates j
supporting the outer water drums are of considerable height, so that they have
sufficient elasticity to permit the drums to yield to the lateral strain exerted on
them by the expansion and contraction of the tubes. The fire-brick, or other.
refractory linings k at the outer sides of the outer fire-boxes are adapted to
conform to the movements of the outer water drums.
The weight of the steam drum is mainly carried by the three intermediate.
water drums, and their supports, which are shorter and stiffer than the

page_text: supports jj. The expansion and contraction of the tubes connecting the
intermediate water drums with the steam drum is compensated for by the move-
ments of the steam drum, the latter being raised by the expansion and lowered by
the contraction of said tubes. ooo represent radiating return pipes which
connect the steam drum with the water drums, said pipes being preferably connected
to a header o common to all the return pipes.
In Figure 7, I show two boilers arranged side by side, each comprising a steam
drum and four water drums. The outer water drums of the combined series are
supported by flexible foundation plates, permitting yielding movements of said
drums, while the steam drums are supported by the tubes connecting them with
the more rigidly supported water drums, as in the construction shown in Figure 4.
Figures 4 and 5 show a double-ended boiler with four furnaces at each end,
intended to take the place of the largest types of Scotch or other marine boilers,
the division wall (Figure 5) subdividing the furnaces into two lengths, with
fire-doors at each end of the boiler. This construction admits of providing
a very large amount of grate surface without having the grate so large in any one
furnace as to be unmanageable.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1st. A boiler or steam generator comprising in its construction a plurality of
cylindrical water drums, each flattened or reduced at its upper portion to form a
tube sheet, a corresponding plurality of series of straight tubes extending upwardly
from said tube sheets and a cylindrical jointless or continuous steam drum attached
to the upper ends of said tubes and arranged parallel with the water drums, the
diameter of said steam drum being substantially equal to or greater than the length
of the longest tubes, so that the tubes may be passed from within the steam drum
to their operative positions.
2nd. A boiler or steam generator comprising in its construction a steam drum,
a plurality of rigidly supported water drums connected with the steam drum by a
corresponding plurality of straight tubes which support the weight of the steam
drum, the latter being adapted to conform to the expansion and contraction of said
tubes, and one or more flexibly supported water drums located at a higher point
than said rigidly supported drums and connected with the steam drum by tubes,
the expansion and contraction of which cause lateral or other movements of the
flexibly supported water drum or drums, as set forth.
Dated this oth
A 1004
CHARLES DELL MOSHER.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.