Improvement in water-tube Bollers.
Year: 1898

page_text: Date of Application, 6th Dec., 1898-Accepted, 11th Mar., 1899
Improvement in water-tube Bollers.
I, JOSEPH AUGUSTUS MILLER, of Butler Exchange, Providence, in the County
of Providence, State of Rhode Island, United States of America, Civil 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 has reference to improvements in water-tube boilers such as
are formed of a series of units, or sections, each of which is connected with the
feed-water supply and the steam-main.
Tubulous or water-tube boilers, and particularly such as are to be used for
marine purposes on board of steamers, should combine the highest possible steam-
generating capacity with the least possible weight in the smallest possible space.
The room for steam-boilers on board of a ship is necessarily limited and every
ton of weight saved increases the freight capacity of the steamer.
As heretofore constructed the fittings connecting the water-tubes exceeded in
weight the weight of the steam-generating tubes, a very large number of joints
more or less rigid and subject to the strain of the expansion and contraction of the
tubes were used. In some types the tubes were expanded into the steam and
water chambers and these had to be made of large diameter so as to permit the
entrance of a person to expand the tubes. Another defect in water-tube boilers,
as heretofore constructed, is found in the connections between the water-tubes and
between the discharging ends of the water-tubes and cases, boxes or fittings into
which the steam and water are discharged, for when the ends of such tubes open
into a chamber the steam and water are discharged together and means have to be
provided for separating the steam from the water; such open ends permit a free
discharge equal to the capacity of the tubes and when the boiler is forced the rapid
generation of the steam forces the water out of the tubes and the tubes are liable
to be burned.
The main difficulties with water-tube boilers have been inaccessibility of the
connecting joints, the difficulty of inspecting and cleaning the exterior and
interior of the steam-generating surfaces and the difficulty of making repairs.
Une object of the invention is to construct a water-tube boiler so that all the
steam-generating surfaces shall be formed of sheet-metal and all the joints made
by expanding the tubes, thus combining the greatest available area of heating
surface and strength, to withstand internal pressure, with the least possible weight
of the boiler when filled with water in actual use.
Another object of the invention is to secure a large heating surface extending
over the fire, at or nearly at right angle to the draught of the fire, by the use of
fewer tubes and fewer connections or joints than heretofore used.
A further object of the invention is to so construct a water-tube boiler that the
joints or connections of the tubes shall not be subjected to strains by the expan-
sion or contraction of the tubes.
Another object of the invention is to construct a water-tube boiler so that the

page_text: units, or parts to which the tubes are connected, may be light and comparatively
small and all the tubes may be readily expanded and secured from the exterior of
the connecting chambers.
Another object of the invention is to construct the ends of the water-tubes so
that the discharge of the steam and water is limited and the steam and water
separately discharged into the connecting chamber or fitting.
Still another object of the invention is to so construct a water-tube boiler that
every joint or connection of the steam-generating tubes may be readily examined
and reached while in position, and, if desired, when the boiler is in use.
A further object of this invention is to so construct a water-tube boiler that the
main heating surface or the water and steam tubes may be readily reached for
cleaning and inspection.
Another object of the invention is to so construct a water-tube boiler that the
interior of the steam-generating surfaces may be readily cleaned and inspected.
And a further object of the invention is to construct a water-tube boiler so that
any one of the units may be quickly removed and duplicate units inserted without
entering the boiler and, therefore, without waiting to cool the same.
The invention consists in the peculiar and novel construction of the units, or
sections, of which the boiler is made up, and the combination of the parts by which
the objects of the invention are secured, as will be more fully set forth hereinafter.
Figure 1 is a vertical sectional view of the water-tube boiler showing one of
the units or sections partly in section.
Figure 2 is a front view of the boiler showing the main portion of the front
supported on hinges arranged to open the front so as to give access to the boiler
proper and permit of the removal or insertion of any one of the units or sections.
Figure 3 is a horizontal sectional view of the front end of the boiler showing
the construction of the front doors.
Figure 4 is a side view, partly in section, of one of the sections or units of the
boiler, and
Figure 5 a rear view of the section.
Figure 6 is a transverse sectional view of the unit-chamber showing the ends
of the steam-generating water-tubes expanded into both of the flattened sides of
the unit-chamber, and the slits in the tubes connecting the interior of the tube
with the interior of the unit-chamber.
Figure 7 is a transverse section of one of the tube ends showing the slits on an
enlarged scale.
Figure 8 is a sectional view of the upper end of one of the unit-chambers
showing the steam-separating tube, the inlet-openings for the steam and the
water-trip protected by a deflector.
Figure 9 is a transverse sectional view of two upper steam-generating tubes
of two adjacent unit-chambers, showing a plate resting on the two tubes for
closing the draught-opening between these tubes.
Similar letters or numerals of reference indicate corresponding parts in all the
figures.
In the drawings A indicates the water-main from which the water is supplied
to the boiler; it is provided with the usual connections to the pump and the
blow-off and these connections are supplied with the usual valves, they are not
shown in the drawings as they form no part of the present invention.
B is the section or unit-chamber; it is preferably made from a steel tube, having
the required diameter and length, by flattening the tube into the form, shown in
section in Figure 6, of practically rectangular section having two flat sides B¹ of
greater width than the two slightly curved sides B². The ends of the unit-cham-
Bers B are closed preferably by welding a piece into the ends.
C, C are the steam-generating tubes; they are bent so as to form loops and the
ends of these tubes extend through the flat sides of the unit-chambers B, being
secured by expanding the tubes,—the ends of the tubes are closed by means of a
plug or cap.

page_text: D indicates a steam-separator tube preferably of larger diameter than the
tubes C, C. The tube D is secured at one end in the unit-chamber B above the
tubes C, C, preferably by expanding the tube D into the unit-chamber B and
closing the end. The opposite end of the tube D is also closed and near the end
it is connected with the steam-chamber E.
The steam-chamber E is provided with the usual steam connections and fittings
which, as they form no part of this invention, are not shown in the drawings.
F indicates the ash-pit; G the grate; H the furnace or combination-chamber;
I the firing-doors; K, K the two parts of the front supported on hinges so that
the front may be readily opened; L a beam extending across the front and forming
part of the framing of the casing of the boiler; M the uptake and N the smoke-
Hue.
O indicates a suitable foundation for the boiler; 1', P¹ the support for the unit-
chamber B, and Q the tile or fire-brick lining of the furnace
The lower part of each unit-chamber B is connected with the water-main A by
pipes in which a union-coupling A¹ is placed, so that any one of the unit-chambers
may be readily disconnected.
The ends of the tubes C, C, are secured in holes, bored into the flat sides of the
unit-chambers, by expanding the tubes, the portion of the tubes within the chamber
are provided on the upper side with the long narrow slit C and near the bottom
with the two slits C2. In place of the two slits C², one slit may be made into the
bottom portion of the tubes preferably of an area equal to the two slits C², C²;
these slits radially discharge the steam and water rushing through the upper ends
of the bent-tubes C, C, and favour the separation of the steam from the water. The
aggregate area of the slits is less than the area of the tube, and the outflow of the
water is retarded when the boiler is forced and facilitates the escape of the steam
which always struggles to escape upward and passes through the upper slit C¹.
The inclined positions of the water-tubes C, C, and the bends C3 facilitate the
separation of, the steam from the water within the tubes, thereby preventing the
accumulation of steam in the tubes, particularly in the lower portions of the tubes
exposed to the direct heat of the fire. The plate C7 is placed between the two
adjacent upper steam-generating tubes C, C, of adjoining sections, so as to compel
the gases to pass among and between the other tubes and retard the escape of the
gases..
In the preferred form of construction shown in the drawings the steam-separator
tube D is provided with two inlet-openings d, d, at the upper part of the portion
of the tube D extending through the unit-chamber B, and with an opening dat
the lower part of the tube D, and below this lower opening da deflector is secured
so that when in the normal condition the tube D is partly filled with water, the
steam and water from the steam-generating tubes C, C, will be deflected in its
upward passage and the steam, carrying some water with it, will enter the tube 1)
by the upper openings d, d, as is indicated by the arrows in Figure 8. While
the water in the steam-generating tubes C, C, and unit-chamber B is in constant
and rapid circulation, the water in the tube D is comparatively quiet and presents
a large surface from which the steam, made in the tube, can readily escape and
pass into the steam-collecting chamber E.
The steam-chamber E is firmly supported on the brackets 7, secured to the
beam L or some other firm and rigid support, and the connecting-pipes e, having
the union e¹, form sufficient supports for the ends of the tubes D: these tubes may,
however, be supported by suitable straps such as L', shown in Figure 1.
While each unit, consisting of the tube D, the unit-chamber B and the bent-
tubes C, C, is sufficiently rigid when in use, it may be strengthened by the strap D',
shown in Figure 1, consisting of a bent iron-strap extending around the tube I)
the ends of which are bolted to a vertical bar extending from near the tubes.C, C,
to near the tube D, and a similar strap, enclosing the upper parts of the tubes C, C,
and having ends bolted to the vertical bar to which the upper strap is bolted, or

page_text: some other similar stay, may be used to facilitate the handling and transporta-
tion of the units.
The ends of the steam-generating tubes C, C, when they have been secured into
the walls of the unit-chamber B by expanding the tubes with a tube-expander,
are closed, preferably by expanding with a suitable expander the cup-shaped
caps Cinto the tubes; this firmly secures the caps and holds the
same against all practical internal pressure. By extending the tubular
portions of the caps beyond the ends of the tubes C a simple tool
inay be used to crimp the cylindrical portion of the cap C, thereby contracting
the diameter of the same and permitting the removal of the caps and their re-use.
I do not wish to confine myself to the use of this form of caps as the ends of the
tubes C may be closed by screw-plugs or other means.
For the purpose of cleaning or inspection the hand-holes Care placed in the
parts of the unit-chamber B, shown in the drawings, or other parts, and closed
in the usual manner.
Any flat portion of the unit-chamber B not stayed by the tubes C may be stayed
by means of the stay-tubes C", consisting of short tubes closed at the ends extend-
ing into the furnace and open at the opposite ends; these tubes are provided with
the slits C, C, they are secured in the unit-chamber exactly as are the ends of the
tubes C, by expanding the tubes with an expander, and the open sides are after-
wards closed by the caps C or otherwise. Bent tubes may, however, be used, as
indicated in broken lines in Figure 1, and located so as to properly stay all parts
of the flat surfaces of the unit-chamber B.
The casing enclosing the boiler may be of sheet-metal lined with tile, fire-brick
or asbestos, for marine purposes it must be strongly framed so as to firmly support
all parts under the varying conditions existing on board a ship, the corner
standards R are preferably formed of heavy angle-iron or steel, the hinges Rare
firmly secured to them so as to support the doors K, K, these doors extend from
the dead-plate g to the beam L so that when opened they give access to the furnace
and the whole of the steam-generating surface of the boiler for inspection, cleaning
or repairs. When a unit or section is disconnected, a barrow, such as is indicated
in broken lines in Figure 1, may be rolled in on the grate and a section drawn
out, and, in the same manner, a section quickly inserted. The fire-doors I form
part of the doors K, while the ash-pit doors F, F, form part of the fixed lower
casing suitable bolts such as the bolts K¹ are provided to firmly secure the
doors K when the boiler is in use.
The units or sections which form the steam-generating part of the boiler are
formed entirely of sheet-metal; they are, for equal area of heating surface and
capacity, to withstand internal pressure of less weight than water-tube boilers as
heretofore constructed, all the joints are made by expanding the tubes into the
tube-sheets, preferably by a roller expander such as is now used to expand boiler-
tubes into the tube-sheets.
The tubes are all free to expand and contract without exerting any strain on
their fastenings due to such expansion or contraction. When repairs are required
the doors K, K, are opened, the fire is drawn, the section requiring repair is dis-
connected from the steam and water chambers and the section may be drawn out
without waiting for the boiler to cool, another section may be inserted and con-
nected and the fires started. The repairs are made while the section is outside
and no one has to enter the boiler or crawl into any contracted spaces to tighten
a joint or make any repairs. In cleaning the boiler, by opening the doors K, K,
all the steam-generating surface may be swept or cleaned by a broom or scraper.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
-:
Claim 1. A water-tube boiler made up of a series of units, or sections, having each
a vertical unit-chamber a series of bent-tubes forming a continuous practically

page_text: U-shaped loop both the ends of which extend through the unit-chamber and are
secured in both sides of the same, and connections between each unit-chamber and
the water and steam mains, whereby joints and fittings are avoided and the heating
surface exposed to the fire is formed of tubes both ends of which are secured to
the same vertical chamber, as described.
2. In a water-tube boiler, the combination with the furnace, the uptake and the
enclosing casing, of a series of units, or sections, each consisting of a vertical
unit-chamber, a series of bent-tubes forming a continuous loop both ends of which
extend through the unit-chamber and are secured to the two sides of the same by
expanding the tubes, a tube secured in the unit-chamber above the bent-tubes,
and connections between the water and steam mains and each section or unit,
whereby the steam generated in the bent-tubes is separated from the water, as
described.
3. In a water-tube boiler, in combination, the furnace with its grate, fire-door
and ash-pit, a unit-chamber of practically rectangular cross-section supported in
the rear of the furnace, its lower part connected with the water-supply, a series
of bent-tubes forming a continuous loop the ends of which extend through and are
secured to both sides of the same unit-chamber, said bent-tubes extending from
the unit-chamber over the furnace, connections between the steam-main and the
upper part of the unit-chamber, and a casing, enclosing the boiler, the front of
which is constructed. so as to be opened, whereby the steam-generating tubes of
each section or unit are free to expand and contract and convenient access may be
had to the steam-generating surface for cleaning and inspection, as described.
4. In a water-tube boiler, the combination with a series of sections, or units,
each consisting of a vertical chamber from which extend a series of bent-tubes
forming continuous loops the ends of which are secured to the vertical chamber,
the furnace, the grate and ash-pit, of a casing enclosing the boiler, the front of
which casing, from the dead-plate upward to the top of the sections, is pivotally
supported and adapted to be swung open, whereby any one of the units, or sections,
may be removed and the steam-generating surface conveniently cleaned, as
described.
5. In a water-tube boiler, the combination with the series of units, or sections,
consisting each of a vertical unit-chamber, a series of bent-tubes forming a con-
tinuous loop both ends of each bent-tube secured in the unit chamber, said bent-
tubes projecting from the unit-chamber in the rear of the furnace forward over
the fire, of a casing enclosing the boiler the front of which having the door or
doors K, the fire-door or doors I forming part of said door or doors K, the
hinges R and the bolts K', whereby the front of the casing may be opened and free
access had to all parts of the steam-generating surface between the grate and the
uptake for cleaning, inspection and repairs, as described.
6. In a water-tube boiler, the combination with the steam-generating tubes
and the furnace, of the casing enclosing the boiler, a door or doors extending
upward from the dead-plate below the firing door or doors, whereby access is had
to the steam-generating surface of the boiler for cleaning and repairs and any
section or part of the boiler may be removed, as described.
7. In a water-tube boiler, composed of a series of sections, or units, the combina-
tion with the unit-chamber B having the flat sides B, B, of the bent-tubes C. C
forming a continuous loop the two ends of each bent tube being secured in both
of the flat sides B', B', of the unit-chamber, openings in the sides of the tubes
connecting the interior of the tubes with the interior of the unit-chamber, the
caps C, consisting of a tube closed at the inner end and secured by expanding the
open-end tubular portion into the open end of the tubes, by which the ends of the
tubes are closed, and connections between the steam and water mains and the unit-
chamber, whereby the tubes, forming the steam-generating surface, extending
from the rear to the front of the boiler over the fire, are free to expand and con-
tract and the joints are protected against the direct action of the fire,
8. In a water-tube boiler, composed of a series of sections. or units, the combina-

page_text: tion with the unit-chamber B and the series of bent-tubes C, C, of the tube D,
the inlet-openings d, d, at the upper part of the tube, the opening d' at the lower
part of the tube, and the deflector, whereby the separation of the steam from the
water is facilitated, as described.
9. In a water-tube boiler, in combination, a series of sections, or units, each
consisting of a unit-chamber of practically rectangular cross-section and extending
vertically from a suitable support in the rear of the furnace, a series of bent tubes
extending from the unit-chamber forward over the fire, the ends of said tubes
being expanded into two of the flat sides of the unit-chamber and the extreme ends
closed, a steam-separating tube secured in the upper part of the unit-chamber
above the bent tubes, connection with the steam and water mains, a casing,
enclosing the boiler, the front of which is formed of a hinged door or doors, where-
by when repairs are required a section may be quickly removed and another section
inserted without entering the boiler, as described.
JOSEPH AUGUSTUS MILLER.
In presence of ;-
JOSEPH A. MILLER, JR.
A. E. HAGERTY,
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.