Improvements in Water-tube Steam Boilers.
Year: 1897

page_text: Date of Application, 30th Oct., 1897
Complete Specification Left, 29th July, 1898–Accepted, 15th Oct.,
1898
Improvements in Water-tube Steam Boilers.
I, HAROLD WORKMAN, B.Sc., of Dunluce, Dullatur, in the County of Dumbar-
ton, North Britain, Engineer, do hereby declare the nature of this invention to
be as follows, that is to say:-
My said invention comprises new or improved arrangements or combinations
of the parts of water-tube steam boilers of the kind having stacks of tubes through
the upper portion of which the water flows downwards automatically.
In some of the improved arrangements separate horizontal or slightly inclined
tubes are fixed in junction boxes which connect the tubes in a manner to form
continuous serpentine passages so that the water may flow through successive
lower tubes or groups of tubes alternately in opposite directions between the
junction boxes. The tubes may be in separate vertical sections, each section com-
prising one or more vertical rows of tubes. The junction boxes in which the
uppermost tubes are fixed are connected to the lower part of a water-and-steam
drum or cylinder which may comprise the sole steam space, or which may be
connected to a higher steam drum. The water communications with the drum
may be comparatively contracted with the view of obstructing any tendency to
upward flow.
The tubes are arranged in one or more stacks over a furnace or furnaces, the
fire gases from which ascending amongst the tubes have their heat more and more
absorbed as they rise, so that the water becomes more and more heated as it
descends. The tubes may be of graduated sizes the upper tubes being the smaller.
One or more of the lowermost tubes or groups of tubes of each vertical section
or row may, with suitable junction boxes, be arranged as ascending tubes, the
lowest of these being connected to the lowest of the other higher tubes, which may
be distinguished as descending tubes; and the highest of the ascending tubes are
connected, by one or more return tubes for each section, to the water-and-steam
drum. The greater heat from the furnace acting on the ascending tubes causes
a vigorous flow of the water (mixed with steam) through them and the return
tubes, in a general upward direction to the drum. The return tubes may be at
either side of the stack of tubes, and in the cases of pairs of stacks they may be
between the stacks or at their outer sides.
Instead of the stacks being built up of separate tube lengths connected by
junction boxes they may consist of long lengths of tubing bent into serpentine
forms; and they may be arranged or grouped in various ways, upper tubes being
made descending tubes, and lower portions ascending tubes. The lower ends of
the descending tubes may be fixed to communicating boxes at the sides of the
stacks, or in the case of pairs of stacks at the middle part between the lower ends
of the stacks, and each communicating box may extend across two or more ver-
tical rows or sections of tubes. The return tubes have their lower ends fixed to
the communicating boxes, and may proceed thence directly up to the drum, or
may extend across the furnace and then up to the drum.

page_text: The tubes may be arranged so as to form a combustion space above the lowest
layer of tubes.
Dated this Twenty-ninth day of October 1897.
EDMUND HUNT,
Applicant's Agent.
Improvements in Water-tube Steam Boilers.
:
I, HAROLD WORKMAN, B.Sc., of Dunluce, Dullatur, in the County of Dumbar-
ton, 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 comprises new or improved arrangements or combinations
of the parts of water-tube steam boilers of the kind having stacks of tubes through
the upper portion of which the water flows downwards automatically.
And in order that my said invention and the manner of performing the same
may be properly understood I hereunto append three sheets of explanatory draw-
ings to be hereinafter referred to and showing four modifications of my improve-
ments.
Figures, 1, and 2, on the accompanying drawings are vertical sections as at
right angles to each other of a boiler as made according to one modification of
my improvements. Figure, 3, is a longitudinal vertical section showing a second
modification of my improvements. Figure, 4, is a transverse vertical section
showing a third modification of my improvements, Figure, 5, being a longitudinal
section of a part of this modification. Figure, 6, is a transverse vertical section
of a fourth modification. In these drawings the same reference letters and
numerals are used to mark the same or like parts wherever they are repeated.
In the boiler shown in Figures, 1, and 2, of the drawings, there is an upper
portion of horizontal or slightly inclined water tubes, A, arranged in vertical
sections, each section comprising a double row of tubes, A. There may be only
one or more than two vertical rows of tubes in each section. The tubes, A, are
fixed at their ends in junction boxes, B, C, made with compartments arranged
so that in each section groups of four tubes, A, communicate through the junction
boxes with each lower or upper set of four alternately at opposite ends so that a
continuous serpentine passage is formed and the water flows through successive
lower groups of tubes alternately in opposite directions between the junction
boxes, B, C. The top group of four tubes, A, in each section is at one end fixed
in a box, D, which communicates with the lower part of a water-and-steam drum, E,
which may comprise the sole steam space, or which may be connected to a higher
steam drum.
The lowest group of four water descending tubes, A, in each section is con-
nected at one end by a long junction box, F, with two small tubes, G, and one
larger tube, H, which tubes, G, H, are connected through a similar box, J, with
a group of tubes, K, which in their turn communicate through a box, L, with
another group of tubes, M, which latter are connected by a return tube, N, for
each section to the water-and-steam drum, E.
The fire gases from the furnace or furnaces, P, beneath each stack of tubes are
prevented from ascending directly amongst the tubes by a lining of fireclay, Q,
or other suitable material placed on and between the group of tubes, G, and the

page_text: 5
ire gases pass by a lateral flue, R, (which may be on one side or on each side)
nto a combustion space, S, between the tubes, G, and K. The tubes, G, H, K,
and M, act as water ascending tubes and the greater heat from the furnace acting
on these ascending tubes causes a vigorous flow of the water (mixed with steam)
through them and the return tubes, N, in a general upward direction to the
drum, E. The fire gases ascending amongst the tubes have their heat more and
more absorbed as they rise, and the water becomes more and more heated as it
descends through the descending tubes, A. The entrance for the water into the
top group of four tubes, A, may be slightly contracted to obstruct any tendency
to a flow in the direction opposite to that intended.
In the modification shown in Figure, 3, the arrangement of the water ascending
tubes and the flue for the passage of the fire gases is slightly varied from the cor-
responding parts in the modification herein before described. The lowest group
of four water descending tubes, A, in each section is connected through the
junction box, F. with only one larger tube, H, which is connected through
a junction box, T, with a similar tube, U, which in its turn is connected through the
junction box, L, with a third large tube, V, and this latter tube is connected by
a return tube, N, for each section to the water-and-steam drum,, E. The two
tubes, H, U, are shorter than the others their inner ends with the junction box, T,
being carried by a fire bridge, W, and this leaves a flue, X, at the back for the
passage of the fire gases to the combustion space, S. The direct ascent of the fire
gases amongst the tubes is prevented by a lining of fireclay, Q, or other suitable
material placed on and between the tubes, U.
Instead of the stacks being built up of separate tube lengths connected by
junction boxes as shown in the modifications hereinbefore described, they may,
as shown in Figures, 4, 5, and 6, consist of long lengths of tubing, Y, Z, bent
into serpentine forms and they may be arranged or grouped in various ways
besides those shown, the portions, Y, being mainly descending tubes, and the
lower portions Z ascending tubes. The lower ends of the descending tubes, Y,
are fixed to a communicating box, F 1, extending across all the vertical rows
or sections of tubes, Y, at the sides of the stacks as shown in Figure, 4, or at
the middle part between the lower ends of the stacks as shown in Figure, 6. Or
separate communicating boxes (F1) may be provided for any one or more of the
vertical rows of tubes, Y. The return tubes, Z, have their lower ends fixed to
the communicating box, F 1, (or boxes) and they extend across the furnace, P,
and then up to the drum, E. The return tubes, Z, may extend more than once
across the furnace, P, before being led up to the drum, E. The connection for
the return tubes, Z, with the drum, E, is at the bottom as shown in Figures, 4,
and 5, but an internal partition, E 1, in the drum leads the water and steam from
the return tubes, Z, to the upper part of the drum where a baffle plate, E2, directs
the water and steam downwards into the drum, E. A somewhat similar parti-
tion, E1, and baffle plate, E 2, is also shown in Figure, 6.
The tubes may be arranged so as to form a combustion space above the lowest
layer of tubes.
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 a stack of horizontal or slightly inclined tubes
connected by end junction boxes, which, in the upper portion of the stack, form
0 communications between each tube or group of tubes and the next lower one,
thereby constituting continuous zigzag or backward and forward and generally
downward passages from the uppermost tubes which are connected to the lower
part of a water-and-steam drum, whilst the tubes forming the lower portion of the
stack have end junction boxes connecting the lowermost tubes of the upper por-
55 tion of the stack with the lowermost tubes of the lower portion, the uppermost

page_text: tubes of the lower portion being connected by junction boxes and tubes to the
water-and-steam drum, and the uppermost and lowermost and intermediate tubes
of the lower portion being connected by end junction boxes to form zigzag or
backward passages, the flow of water due to the construction and arrangement
being downwards through the upper portion and upwards through the lower
portion substantially as herein before described with reference to Figures, 1, 2,
and 3, of the accompanying drawings.
2. In a water-tube steam boiler, comprising a stack of horizontal or slightly
inclined tubes connected by end junction boxes, the arrangement of the lowermost
tubes at a distance below the next higher tubes to form a combustion space which
communicates with the furnace space, the said lowermost tubes having their
interstices closed, substantially as hereinbefore described.
3. In a water-tube steam boiler, a stack of tubes consisting of long lengths of
tubing bent into serpentine forms connected at their upper ends to a water-and-
steam drum and at their lower ends to a communicating box or boxes from which
return tubes extend up to the drum the parts being arranged and operating
substantially as hereinbefore described with reference to Figures, 4, 5, and 6, of
the accompanying drawings.