Improvements in or relating to Water-tube Boilers.
Year: 1899

page_text: Date of Application, 30th Mar., 1899-Accepted, 10th June, 1899
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Improvements in or relating to Water-tube Boilers.
A communication from MARTIN PRIOR BOSS, residing in the City and County of
San Francisco, State of California, United States of America, located and
doing business as an Engineer at 309, California Street, in the City and
County and State aforesaid.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, 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 invention relates to certain new and useful improvements in what is
known as water-tube boilers and more particularly to that class of boilers having
water-tubes connecting two water-cylinders which are exposed to the fire only
from the outside, and the invention consists of a plurality of series or groups of
water-tubes connecting two cylinders, each series or group of tubes being so
seggregated and inclosed that the space around and between the tubes shall
form a flue; except that the base of the first series of tubes may spring from the
midst, or at one side of the fire chamber.
The invention also consists of other details of construction and arrangement,
all of which will be hereinafter fully described..
The general object of this invention is to provide a simple and efficient water-
tube boiler with maximum heating surface, good water circulation, deposit of
sediment below fire level and accessibility and convenience for cleaning and
repairs; and also free expansion and contraction.
Referring to the accompanying. drawings, Figure one is a longitudinal section
through the boiler, which in this case shows but two series of tubes; Figure two
is a transverse section on line of Figure one through fire-chamber and first
series of tubes; Figure three is a transverse section on line y-y of Figure one
through the last series of tubes and the base of the chimney, Figure four is the
front elevation of complete boiler; Figure five is a plan of the same; Figure six
is a vertical cross sectional view of the boiler, showing a modification as to con-
struction of the flues for the water-tubes, the same being taken through the fire
chamber and first series of tubes; Figure seven is a similar view of boiler taken
through the last series of flues and the base of the chimney; and Figure eight
is a longitudinal cross sectional top plan view, taken on line ar Figure 6.
In the drawings the letters A and B are used to indicate two cylinders con-
nected by the separated series or groups of tubes C and C. D is the fire
chamber and F the base of the chimney. The group of tubes C and C¹, it will
be seen are separated by a wall H, and the spaces inclosing the tubes form
flues D1, D2, through which the heat currents pass. At the upper portion, these
flues are widened out as shown in Figure two, to form a flue F in proximity

page_text: to the upper cylinder B, said widened flue F extending across the two series
or groups of tubes, thus providing ample capacity for the heat currents to pass
from series C to series C¹.
If the flue was not widened at F, the division wall H could not be carried so
high without restricting the heat currents; and the upper end of the tubes
farthest from the division wall H would be wholly without the heat currents
and, therefore, less effective.
In operation the flame passes from fire-chamber D, vertically through flue D'
containing group C and horizontally through flue F, thence downward through
flue D2, containing group C and out at a side opening into the chimney E.
To enable the connecting of the straight vertical tubes to the water-cylinders A
and B, and to keep them all parallel throughout, my correspondent interposes
into a side of each cylinder a flat plate K, sufficiently thick to withstand, without
bulging, the great pressure within the cylinder. This plate is flanged at the
sides as shown at k (Figure two) to conform to the curvature of the cylinder in
order to facilitate the riveting of it into the cylinder. The form of this plate
is such that it may be rolled, as bar iron (at a rolling mill), of any desired
length.
To enable the removal or the replacing of a tube, my correspondent puts into
upper cylinder B, a removable plate m opposite to each series of tubes, through
which opening, any tube may be removed by first removing the plate.
If found desirable to retard or check the travel of the flame and hot products
of combustion through the water tube flues D', D2 in order to confine the same and
drive it during travel directly against the group or series of tubes C, C' located
therein, the flues D1, D2 may be constructed with the inwardly projecting
shelves, ledges or shoulders 1, 2 which are so arranged as to alternate from side
to side of the flue, as clearly illustrated in Figures six and seven of the drawings.
The clearance or passageway thus left between the water tubes and the inner wall
of the flues is of such a character that the flame or hot products of combustion
will not travel in a straight line, but be deflected from side to side during travel
thereof through the flues within which the water tubes are situated. This con-
struction of the walls of the flues D1, D2 causes the flame or hot products of
combustion to travel in a zig-zag or staggered direction and during travel to be
thrown directly against the water tubes situated in the flues, thus subjecting the
.tubes to the full effect of the flames or products of combustion during travel
from the fire chamber to the chimney and permitting the maximum efficiency
of heat to be obtained by such retardation of the flame or hot products of com-
bustion within the flues.
Having now particularly described and ascertained the nature of the said in-
vention as communicated to me by my foreign correspondent and in what manner
the same is to be performed, I declare that what I claim is:
1st. A water-tube boiler having a plurality of series, groups, or nests of water-
tubes connecting two water-cylinders, said series, groups or nests being separated
and their spaces in which they are confined forming flues, which communicate
successively to give alternate currents in opposite directions.
2nd. A water-tube boiler, having a plurality of series, groups or nests of
water tubes connecting two water-cylinders, division walls separating adjacent
series, groups or nests, a communication between the flue spaces inclosing adjacent
series, groups or nests, at alternately opposite ends, whereby alternate currents
in opposite directions are had, and an exit for the currents from the final series,
group or nest.
3rd. A water-tube boiler having a plurality of series, groups or nests of water-
tubes connecting two water-cylinders, said series, groups or nests being separated,
and their space confining them forming flues which communicate successively,
that section or sections of said flues at or near the water-cylinders being widened,

page_text: to form a wider flue section, extending parallel to the cylinders, and across two
adjoining tube series, groups or nests.
4th. A water-tube boiler, having a plurality of series, groups or nests of water-
tubés connecting two water-cylinders, division walls separating adjacent series,
groups or nests, a communication between the flue spaces inclosing adjacent
series, groups or nests, at alternately opposite ends, whereby alternate currents
in opposite directions are had, said flue spaces having that section at or near the
water cylinders widened, to form a wider flue section extending parallel to the
cylinders and across two adjacent tube series, groups or nests, and an exit for
the currents from the final series, group or nest.
5th. In a water-tube boiler having a water-cylinder, a flat tube plate inserted
in one side of said cylinder sufficiently thick to withstand, without bulging, the
pressure within, said plate having flanges, at its sides to conform to the curva-
ture of the cylinder, in order to facilitate the riveting of it into the cylinder.
Gth. In a water-tube boiler having two cylinders connected by a nest or group
or by nests or groups of water-tubes, a removable plate or cover opposite each
uest or group in one of the cylinders, whereby upon removing the plate or cover
any tube in the nest or group can be withdrawn through the plate opening.
7th. A water-tube boiler having a plurality of series, groups or nests of water-
tubes connecting two water-cylinders, said series, groups or nests being separated
and their spaces in which they are confined forming flues which communicate
successively to give alternate currents in opposite directions each flue being
formed zig-zag or staggered whereby the flame or current of hot products of com-
bustion will be confined during travel through the flues and directed against the
water-tubes located therein.
8th. In a water-tube boiler of the described character, the combination with
the water-tube space, of a partition sub-dividing the same into distinct flues, a
series or group of water tubes located in each Hue, a staggered, zig-zag or ser-
pentine passage-way for the flame or hot products of combustion in each water
tube flue, and of a connecting flue for the said water tube flues.
9th. In a water-tube boiler of the described character, the combination of a
plurality of water-tube flues, a series or group of water tubes located in each
Hue, a series of shoulders or projections secured to the side walls of each flue at
points diagonally opposite each other so as to form a zig-zag, staggered or ser-
pentine pathway between the water-tubes and the walls of the flues through
which the flames or hot products of combustion is conveyed, and of a flue forming
connection between the water-tube flues.
Dated this Thirty-first day of December 1898.

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