Year: 1897

page_text: I, HAROLD WORKMAN, B.Sc., of Dunluce, Dullatur, in the County of Dumbarton,
North Britain, Engineer, do hereby declare the nature of this invention to be as
follows, that is to say :-
My said invention bas mainly for its object, by improved constructions and arrange-
ments to increase the efficiency of water-tubo steam boilers, some of the improve-
ments being also applicable to other types of steam boilers.
A boiler made with my improvements comprises a stack of water tubes which may
be horizontal or slightly inclined and which constitute the main heating surface, the
furnace being placed beneath the stack of tubes. The tubes are formed into a number
of vertical sets or sections, and those of each section, which may consist of one or more
vertical rows of tubes, are connected at their ends by junction boxes in a manner to
form a continuous coil or serpentine water passage from top to bottom.
The upper
end of each section of tubes is connected to the lower part of a drum which is partly
occupied by water its upper part forming a steam space, either alone or connected to
au upper or supplementary steam drun. The lower end of each section of tubes is
connected by one or more return tubes to the upper part of the water-and-steam
drum, the return tube or tubes being vertical or otherwise as short and direct as can
be conveniently arranged. The return tabes are, if necessary, heated by a portion of
the fire gases.
It is an important feature of my improved arrangement that the water flows down-.
wards through the stack of tubes, the water and steam flowing upwards through the
return tubes. The action of the furnace and fire gases is most intense on the bottom
tubes, the intensity becoming gradually less as the fire gases reach one upper tier of
tubes after another. The descending water is consequently subjected to increasing
heat in proportion as it descends; and very completely utilises the heat of the fire
gases, which become reduced to a comparatively low temperature on reaching the top
of the stack of tubes. Heat remaining in the fire gases may be further utilised by
being made to act on tubes arranged in the uptake and having the feed water passed
through them. The feed water is, by preference, led into a horizontal tube immersed
in the water in the water-and-steam drum, the tube having orifices or nozzles opposite
the communications with the several sections of the stack of water tubes.
The boiler is enclosed in a double casing consisting of an outer metal shell and an
innor metal casing lined with firebrick, and air is forced or drawn through the space
between the shell and inner casing to take up available heat. The air thus heated is
directed into the furnace through apertures in the firebrick casing and in a hollow
bridge; and tubes of fireclay or other suitable material are arranged as a grating
above the level of the fuel in the furnace, snch tubes being perforated and having
heated air supplied to them, which air, issuing through the perforations, insures com-
plete combustion in the furnace. Or the grating over the fuel may consist of solid

page_text: bars or pieces of fireclay or the like. Regulating valves are arranged in connection
with the various air inlets, so that the distribution and action of the air may be con-
trolled as may be found best in practice.
The arrangement and manner of combining the water tubes are susceptible of
variation in different cases, the feature of the downward flow of the water through
thom being essential in applying any invention.
A complete boiler may consist of a single stack of water tubes arranged as herein-
before described; or it may consist of two stacks connected to a single water-and-
steam drum, the return tubes being between the two stacks. Or more than two
stacks of water tubes may be combined.
The improved furnace details hereinbefore described, especially the fireclay air
'injecting tubes above the fuel, are advantageously applicable to various kinds of steain
boilers.
I, HAROLD WORKMAN, B.Sc., of Dunluce, Dullatur, in the County of Dumbarton,
North Britain, 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, that is to say :-
My said invention has mainly for its object, by improved constructions and
arrangements, to increase the efficiency of water-tube steam boilers some of the
improvements being also applicable to other types of steam boilers.
A boiler made with my improvements comprises a stack of water tubes which may
be horizontal or slightly inclined, and which constitute the main henting surface, the
furnace being placed, beneath the stack of tubes. The tubes are formed into a
number of vertical sets or sections, and those of each section, which may consist of
one. or more vertical rows of tubes, are connected at their ends by junction boxes in
a manner to form in ench case one or more serpentine water passages from top to
bottoui.
It is an important feature of my improved arrangements that the water flows
downwards through the stack of tubes the water and steam flowing upwards through
return tubes. The action of the furnace and fire gases is most intense on the bottom
tubes, the intensity becoming gradually less as the fire gases reach one upper tier
of tubes after another. The descending water is cousequently subjected to increasing
heat in proportion as it descends; and very completely utilises the heat of the fire
gases, which become reduced to a comparatively low temperature on reaching the top
of the stack of tubes. Heat remaining in the fire gases may be further utilised by
being made to act ou tubes arranged in the uptake and having the feed water
passed through them. The feed water is, by preference, led into a horizontal tube
immersed in the water in a water-and-steam drum, the tube having orifices or
nozzles opposite comniunications with the several sections of the stack of water tubes.
My invention also comprises certain furnace arrangements which may be used with
iny improved water-tube arrangement of boiler, or with other types of boiler. For
the purposes of this part of my invention the boiler is enclosed in a double casing,
and air is forced or drawn through the space between the casings, and taking up heat
therein is directed into the furnace through apertures in the sides and in a hollow
bridge, and in some cases through tubes of fire-brick or other suitable material, such

page_text: tubes being arranged as a grating above the level of the fuel in the furnace, and
being perforated, the air issuing through the perforations insuring complete com-
bustion in the furnace. Or the grating over the fuel may consist of solid bars
or pieces of firebrick or the like.
And in order that ny said invention and the manuer of performing the same may
be properly understood I hereunto append two sheets of explanatory drawings to be
hereinafter referred to and showing some examples of boilers as made with my
improvements.
Figure, 1, on Sheet, 1, of the drawings is a vertical section and Figure, 2, is a vertical
section as at right angles to Figure, 1, of one example of my improved boilers.
Figures, 3, and 4, on Sheet, 2, are similar views of a second example, Figure, 5, showing
part of a third example, and Figures, 6, and 7, showing a fourth example.
In these drawings the same reference letters are used to mark the same or like
parts wherever they are repeated.
In the boiler shown in Figures, 1, and 2, there is a stack of horizontal water
tubes, A, arranged in vertical sections each section (in this example) comprising a
Bingle vertical row of tubes. The tubes are fixed at their ends in junction
boxes, B, C, those, B, at one end consisting of a vertical set of sepamte boxes each
connecting two tubes, whilat a single vertical box, C, is shown at the other end, being
made with compartments each connecting two tubes. Separate junction boxes inay
however be used at both ends of the tubes. The top tube, A, of the stack is at one
end fixed in a box, D, communicating with the bottom or lower part of a water-and-
steam drum, E; aud its other end communicates through the box, C, with the second
or next lower tube, which communicates through a box, B, with the third tube; and
in a similar way communication is made between each tube and the next lower only
alternately at opposite ends, so that a continuous serpentine passage is formed
through the tubes of each vertical section from top to bottom of the stack. The
bottom tube of the stack communicates through a junction box, F, with a vertical
tube, G, which communicates through a tube, H, and junction boxes with the water-
and-steam drum, E. The furnace, J, is directly under the stack of tubes, and its
heat acting most strongly on the lower tubes causes an upward flow of water and
steam through the ascension tubes, G, H, whilst water descends through the
tubes, A, forming the stack, and a vigorous circulation is maintained.
In the example shown in Figures, 3, and 4, each section of tubes, A, of the stack
consists of two vertical rows, the tubes being connected by junction boxes, B, C, at
their ends. The tubes are slightly inclined, those of one vertical row in one direction
and those of the other row in the other direction, and each junction box or compart-
ment, B or C, connects a tube inclined downwards to it with a tube inclined down-
ward froin it, so that the flow is alternately through the tubes of the two rows.
this example also, both connections (for each section of tubes) with the water-and-
steam drum, E, are shown as at the bottom of the dram, but an internal partition, Q,
may be arranged to lead the ascending water and steam to the upper part of the
drum.
In
In the example partly shown in Figure, 5, each section of tubes, A, of the stack,
consists of two vertical rows, of tubes, the junction boxes being; arranged, so that
both tubes of each vertical pair communicate with both tubes of each lower or upper
pair.
In the example shown in Figures, 6, and 7, the tubes, A, of the stack are divided
into groups of four each set of four communicating through the junction boxes with
each lower or upper set of four.
The arrangement and manner of combining the water tubes are susceptible of
variation in other ways besides those shown, the feature of the downward flow of
the water through them being essential in applying my invention.
The water-and-stean drom, E, in any of the modifications may be connected to an
upper steam drum. The tubes, A, may be of graduated sizes, the upper tubes being
the smaller. The entrances for the water into the tubes may be slightly contracted
to obstruct any tendency to a flow in the direction opposite to that intended.

page_text: The boiler is, by preference, enclosed in a double casing, consisting of an outer
metal shell, K, and an inner metal casing lined with firebrick, L, and air is forced
or drawn (by means of any suitable known apparatus) through the space between the
sbell, K, and inner casing, L, to take up available heat, partitions being by preference
arranged in the space to cause the air to take a circuitous course.
The air thus heated may be directed into the furunce, J, through apertures, M,
in the firebrick casing, L, and in a hollow bridge, N, as shown in Figures, 1, 2, 6,
and 7, and tubes, P, of firebrick or other suitable material may, as shown in
Figures, 6, aud 7, be arranged as a grating above the level of the fuel in the furnace,
such tubes being perforated and having heated air supplied to them, which air
issuing through the perforations, insures complete combustion in the furnace.
Regulating valves may be arranged in connection with the various air inlets, so
that the distribution and action of the air may be controlled as may be found best in
practice.
.
A complete boiler may consist of a single stack of water tubes, A, arranged, with
furnace and accessory parts as herein before described, or it may consist of two stacka
connected to a single water-and-steam drum, the return tubes (G) being between the
'two stroke. Or more than two stacks of water tubes may be combined.
:
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a water-tube steam boiler arranging horizontal or slightly inclined water
tubes in a stack with end junction boxes, the uppermost tubes being connected to
the bottom or lower part of a water-and-steam drum, and the lowermost tubes being
connected to the same drum, in such a manner that the heat of the furnace, which is
below the stack of tubes, causes the water to flow downwards through the stack of
tubes, the parts being combined and operating substantially as hereinbefore
described:
2. In and connected with a furnace for a water-tube or other steam boiler, the
combination of a double casing through which air is passed, with apertures in the
sides and bridge of the furnace, and with perforated firebrick tubes above the level of
the fuel, for the heating of the air and its distribution in the furnace, substantially as
hereinbefore described.
Dated this Twenty-ninth day of October 1807