Improvements in Water Tube Steam Generators and Feed Water Evaporators.
Year: 1899

page_text: PROVISIONAL SPECIFICATION:
Improvements in Water Tube Steam Generators and Feed Water
Evaporators.
ROBERT BRUCE SMITH, Helenbank, 22, Kingsland Road, Birkenhead, Engineer,
do hereby declare the nature of this invention to be as follows:-
My said invention has for its object the improvement of steam generators of
the kind known as water tube steam generators, in which the water to be
cvaporated into steam is contained within the tubes, and their connections, and
the heat applied to their external surfaces, so as to produce steam more rapidly
and safely, to make the construction of them cheaper and to be more easily
scaled and cleaned, and repaired.
In carrying out my invention I compel the water to be evaporated into steam
to pass twice (possibly more than twice) through the heat of the furnace. To
do so I arrange a stack or stacks of tubes sloping upwards to the right hand or
to the left, or both, over the fire or fires from a lower water chamber the inside
of which is common to all the tube ends in the lower stack or stacks, to a
higher similar water chamber, or chambers, and another secondary stack or
stacks of tubes from the said higher water chamber or chambers, sloping
upwards in an opposite direction (or directions) to the lower stack or stacks of
tubes so as to pass over the fire to a still higher water chamber, and so on
through any series of stacks of tubes which may be thought desirable.
This last chamber I connect to a cylindrical receiver with closed ends which
receives the steam as it is generated, and upon which the usual mountings are
fixed for the working of the generator, or I may preferably fit the high ends
of the last stack of tubes direct into this receiver, and omit the top water
chamber.
I also connect the top water chamber, or the said receiver with the lowest water
chamber by downcast tubes, so that the circulation of the water through the
tubes over the fire may be perfectly maintained.
I also may make the lower stack of tubes, or the lower rows of tubes in the
stack, or stacks nearest the fire larger in diameter, than the tubes above them,
or vice versa if it is found necessary to give a freer flow to the steam and water
through the upper tubes. Or I may make the Jower stack of tubes larger in
liameter, but those in the upper stack or stacks I may keep smaller, but make
he total area greater by increasing their number.
By my invention of one stack, or stacks of tubes over the other, with water
hambers placed at the ends to keep them full of water, thereby causing the
vater to be evaporated to pass twice (or oftener) over the fire, I secure a more
apid and perfect circulation of the water through the tubes, and consequently
more rapid generation of steam, with greater safety to the tubes, the danger
f their burning, or of collapsing through overheating being minimized,

page_text: Then by my invention of the water chambers placed as aforesaid I am enabled
to make openings the full size of each tube plate by which the tubes can be
put in place and the ends fixed, also defective tubes can be removed, and leak-
ages or other defects made good, and scaling or cleaning of the insides of the
tubes can easily be done. These openings I close by doors bolted on, or other-
wise made steam and water tight.
=
I also arrange suitable current guiding plates to separate between the hot
water & steam Howing to the receiver, and the colder water flowing through the
down cast tubes to the lowest water chamber.
Further by my invention the space of triangular section formed between the
upper and lower stacks of tubes I form into a combustion chamber, and intro-
duce. air to aid in the better combustion of the gases after they have passed
through the lower stacks of tubes.
I may also place a stack of tubes among the waste gases of the furnaces to
economise fuel by heating the feed water before it enters into the generator.
One element of this generator, or a small form of it may suitably be used as an
evaporator to replace the loss of fresh water by leakage from a larger installa-
tion of this, or of any other form of marine boilers when working at sea, owing
to its being easily and thoroughly scaled in a very short time.
I may
also fit tubes between the top and bottom water chambers to form a
560 water" back to the combustion chamber.
COMPLETE SPECIFICATION.
Improvements in Water Tube Steam Generators and Feed Water
Evaporators.
I, ROBERT BRUCE SMITH, of 38, Porterfield Road, Renfrew, formerly of Helen-
bank, 22, Kingsland Road, Birkenhead, Engineer, do hereby declare the nature
of this invention and in what manner the same is to be performed to be parti-
cularly described and ascertained in and by the following statement:-
My said invention relates to steam generators of the kind known as water tube
steam generators wherein the water to be evaporated into steam is contained
within the tubes and their connections, the heat being applied to their external
surfaces; and the object of my invention is to so construct such steam generators
that they will produce steam more rapidly and safely and be more easily scaled,
cleaned and repaired and be more cheaply constructed than heretofore.
A steam generator according to my invention is illustrated in the accompanying
drawings, Figure 1 being a sectional elevation thereof. Figure 2 is a front view
of the generator and Figure 3 is a rear view thereof. Figures 4 and 5 illustrate
a modified construction of the generator.
Upon reference to the drawings it will be seen that I cause the water which
is to be evaporated into steam to pass several times through the heat of the
furnace a. To do so I employ a series of water chambers b, c and d and a
steam receiving chamber e and I arrange stacks of tubes so as to form with such
chambers a continuous waterway, namely a stack of tubes f slopes upwards
across the furnace from the chamber 6 to the chamber c, and an upper stack of
tubes slopes upwards from the chamber c to the chamber d, whilst a still

page_text: higher stack of tubes h slopes upwards from the chamber d to the steam receiv-
ing chamber e. It will be noted that the tubes 9 slope in a different direction to
that of the tubes f, h, whereby a zig-zag course is afforded to the water in pass-
ing through the combustion chamber and the gases of combustion are. given a
zig-zag course by brick baffles i. The number of water chambers and their con-
necting stacks may be added to or reduced if thought desirable. The chamber e
is of cylindrical form with closed ends and receives the steam as it is generated,
and upon this chamber are fixed the usual mountings for the working of the
generator.
The chamber e and the water chamber 6 are connected by downcast tubes & so
that the circulation of the water through the tubes and chambers above enume-
rated may be perfectly maintained.
In the example of steam generator illustrated the tubes of the stack f are of
larger diameter than that of the tubes of the stack g, and the tubes are larger
in diameter than the tubes h, but if it is found necessary to give a freer flow to
the steam and water the upper tubes may be of larger diameter than the lower.
Or where the lower tubes are larger in diameter than the upper tubes I may
increase the upper tube area by increasing the number of such upper tubes.
The chambers b and d are directly connected by tubes 7, and the chambers c
and e are directly connected by tubes m, thus providing the combustion chamber
with a water back and a water front.
I may also arrange suitable current guiding plates to separate the hot water
and steam flowing into the receiver e from the colder water flowing through the
downcast tubes k to the lowest water chamber. I may also place a stack of tubes
among the waste gases of the furnace for the purpose of heating the feed water
before it enters the generator and so economise fuel. The chambers b, c and d are
closed by doors n which are bolted on or otherwise made steam and watertight.
By means of these doors I have access to the tube plates for the purpose of fixing
the tubes, removing defective tubes, scaling, cleaning and repairing the tubes.
The triangularly shaped spaces between the tube stacks form combustion
chambers into which air may be introduced by the air mixers o. p is the feed
water inlet.
Figure 4 is a front sectional elevation and Figure 5 is a side sectional elevation
illustrating a modified construction of the water chambers c and d. According to
this modification I divide such chambers into a series of sectional chambers or
elements instead of employing one chamber, which is common to the tubes of a
stack, and into these sectional chambers I lead nests of tubes as shewn. Access
to these tubes may be had by the manholes n¹.
One element of the steam generator constructed as shewn in Figures 4 and 5.
.c., a single set of chambers b, c, d, e, and their connections, or a small form of
the larger generator shewn in Figures 1 to 3, may be used as an evaporator by
which to replace the loss of fresh water due to leakage from the steam generator
proper when working at sea, the construction of such evaporator lending itself
to a quick and thorough scaling thereof.
The tubes forming the stacks f, g, h may with advantage be slightly curved
to allow for expansion and contraction.
By my invention a steam generator comprising stacks of tubes arranged one
over the other with water chambers placed at their ends whereby they are kept
full of water, the water to be evaporated is passed twice or oftener over the fire
and I obtain a more rapid generation of steam with greater safety to the tubes,
the danger of their burning or collapsing through over heating being minimized.
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:-
The combination in a water tube steam generator or feed water evaporator, of

page_text: ‹ the water chambers bed and e and the water tubes fg, h and k arranged, con-
structed and operating substantially as herein set forth with reference to the
-annexed drawings.
2. Dated this 19th day of March 1900..
J. A. COUBROUGH,
Chartered Patent Agent, 10, St. George's Crescent, Liverpool,
Agent for the Applicant.