Improvements in Steam Generators and Superheaters, and in Apparatus and Appliances connected therewith.
Year: 1898

page_text: FRUYIDIONAL DIECIFICATION.
Improvements in Steam Generators and Superheaters, and in
Apparatus and Appliances connected therewith.
I, WILLIAM HENRY WATKINSON, of The Pines, Crookston, near Paisley, N.B.,
Professor of Engineering in the Glasgow and West of Scotland Technical
College, do hereby declare the nature of this invention to be as follows;
My invention consists of, firstly:-Improved arrangements and combinations
for ensuring more perfect and more rapid combustion in connection with steam
generators; for lessening the labour of stoking, and at the same time for
obviating or reducing the production of smoke, without the necessity of a great
excess of air.
Secondly Improved arrangements and combinations of steam superheating
apparatus, so that the amount of heating surface required for this purpose may
be a minimum, and so that the superheater, although subjected to as high a
temperature as possible during the time that it is doing its maximum work, may
be protected from high temperatures when no steam is flowing through it, and
so that the amount of superheating may be regulated, either automatically or
otherwise;
:
Thirdly Of improved arrangements and combinations for heating the feed
water to, or nearly to, the boiling point before it is allowed to mix with the bulk
of the water within the boiler;
Fourthly Of a combination of a steam generator, appliances for heating
the air for the furnaces of the generator, and a feed water heater in which the
water is heated, by contact with steam, to or nearly to the temperature of the
boiling point;
Fifthly Of improved apparatus and appliances for heating the air for the
furnaces of steam generators.
In order to secure more perfect combustion, to lessen the labour of stoking,
and at the same time to obviate or reduce the production of smoke, I arrange
for the complete gasification of the fuel, in a gas producer which forms part of
the boiler instead of being external to it as in all the arrangements hitherto
proposed. This internal gas producer may be arranged in many ways, and in
connection with many varieties of boilers, but a description of its application to
the boiler described in my Specification No. 15721 dated 16th July 1896, will
enable its application to other types of boilers to be readily understood.
In its simplest form my improved boiler consists of two upper and two lower
drums placed parallel to each other at suitable distances apart, and provided
with suitable downcomers" which may be either internal or external.
*
2
"
The
'upcomers consist, firstly, of two walls of tubes each connecting an upper
drum with its corresponding lower one. The tubes in each of these walls are
placed close together, and the space between the two walls forms the gas pro-
ducer. The ends of this space and of the whole boiler may be built up of..fire-

page_text: brick, or of tubes forming part of the boiler; Secondly, two outer walls of
tubes, each connecting its upper drum with its corresponding lower drum. The
tubes in each of these walls are placed at very small distances apart in order
that the products of combustion may be divided into thin sheets as they pass
between the tubes. The spaces between the inner and the outer walls form
combustion chambers. The gases from the producer flow into these combus-
tion chambers, where they are mixed with air and burned. A combustion
chamber may also be formed within the gas producer, air being supplied to this
space in order that partial combustion may take place in this primary combus-
tion chamber.
The fuel may be supplied to the gas producer through hoppers, or both the
supply of the fuel and the removal of the ashes may be accomplished by the use
of helical or other conveyors.
The grate supporting the fuel in the producer may consist of water tubes and
form part of the boiler, or the grate may consist of a channel-shaped casting,
the upper parts of the sides of the channel being grid-like with the bars approxi-
mately vertical. The lower part of this channel-shaped grate is submerged in
water, and the ashes which collect in the bottom of this channel are removed
automatically by a worm working longitudinally in this channel.
"
In my improved arrangements for superheating the steam the superheater is
put in
parallel with the whole or part of the ordinary boiler heating sur-
face, instead of being put in series" with it as in other superheaters. A suit-
able valve is provided for regulating the amount of the hot products which flow
through this shunt" circuit, and for stopping the flow altogether when steam
is not passing through the superheater. This valve may be regulated by hand
or automatically so as to cause a constant amount of superheating, or so as to
vary the amount by which the steam is superheated in accordance with the
variations in the point of cut off in the steam engine cylinder. In order to
maintain the temperature constant to which the steam is superheated I place in
the main steam-pipe, through which the steam passes from the superheater, a
tube, closed at one end, containing a suitable liquid, and outside the steam-pipe
is fixed a corrugated diaphragm box which is in communication with the internal
tubo containing the liquid. The liquid, or its vapour, presses on the corrugated
diaphragm and the motion produced by the changes in the fluid pressure, due
to changes in the temperature of the superheated steam, is magnified by "lazy
tongs" and transmitted to the superheater damper through a rod or chain.
In order to vary the temperature to which the steam is superheated in accord-
ance with the variations in the point of cut-off in the steam engine I employ a
Knowles' supplementary governor, driven by the steam engine, to vary the
length of the chain attached to a lever on the damper spindle. When the
speed of the engine is varied one or the other of two collars on the rotating
sleeve of the governor gears with and drives a friction pulley, on the spindle
of which is a worm which gears with a worm wheel and on the worm wheel
shaft is a chain pulley. When the load on the engine is varied the speed also
varies and the friction wheel is driven in one direction or the other until the
engine speed becomes normal again. During this time the damper chain is
being wound on to the chain wheel or unwound from it; thus varying the
position of the damper.
The damper is arranged so that after maximum opening has been attained
continued motion in the same direction will partially or entirely close it again.
The superheater may consist of a number of tubes or coils of tubing arranged
in parallel between suitable headers and so close together that the products of
combustion are divided into thin sheets in passing between the tubes. These
tubes may be flattened or elliptical in their transverse section and they may,
preferably be arranged with their major axes parallel to one another.
In order to raise the temperature of the feed water to, or nearly to, the
temperature of the boiling point I cause it to flow in thin sheets or films over

page_text: suitable surfaces while it and they are exposed to steam at the full boiler
pressure.
These surfaces may, preferably, be roughened.
In another modification the water is caused to flow over sheets of wire gauze
in order that it may be caused to spread in thin films, both sides of which are
exposed to the steam.
This apparatus may be placed in a vessel external to the boiler, or it may be
placed in the steam drum of the boiler. When it is placed within the steam
drum I arrange to isolate it it, by a diaphram and a steam jacket, from the rest
of the steam space with the object of preventing the steam for the engines
becoming wet before it leaves the boiler.
In order to heat the air required for the boiler furnaces I employ an air-
heater consisting of a number of parallel sheets of metal which may be either
plane, embossed, or corrugated. These sheets are fixed within a casing at suit-
able distances apart, so that the spaces between them form flues or passages.
Suitable ports are arranged near each end of these flues. The products of com-
bustion after leaving the boiler flow through every alternate flue or passage and
the air on its way to the boiler flows through the other alternate flues in this
air-heater and thus has its temperature raised by the heat abstracted from the
products of combustion. Instead of building the air-heater of sheets, as
described above, I may build it of flattened tubes, fixed between tube plates.
These tubes may have their sides either plane, embossed, or corrugated. When
the flues of the air-heater, built up in either of the above ways, are plane I
arrange a number of transverse diaphrams in these flues in order to greatly
reduce the flue area where they are fixed: with the object of causing more rapid
mixing of the products of combustion and of the air in their respective flues.
In another modification I arrange to heat the air in the casing of the boiler,
which is for this purpose made double, and which is built up of corrugated
sheets with the object of causing more rapid interchange of heat between the
products of combustion and the air.
1000
:
Improvements in Steam Generators and Superheaters and in
Apparatus and Appliances connected therewith.
I, WILLIAM HENRY WATKINSON, of The Pines, Crookston, Renfrewshire,
Professor of Prime Movers in The Glasgow and West of Scotland Technical
College, 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;-
-
My invention consists of, firstly, improved arrangements and combinations
for ensuring more perfect and more rapid combustion in connection with steam
generators; for lessening the labour of stoking, and at the same time for
obviating or reducing the production of smoke, without the necessity of a great
excess of air; secondly, improved arrangements and combinations of steam
superheating apparatus so that the amount of heating surface required for this
purpose may be a minimum and so that the superheater, although subjected to
as high a temperature as possible during the time that it is doing its maximum
work may be protected from high temperatures when no steam is flowing through
it, and so that the amount of superheating may be regulated, either automati-

page_text: cally or otherwise; thirdly, of improved arrangements and combinations for
heating the feed water to, or nearly to, the boiling point before it is allowed to
mix with the bulk of the water within the boiler; fourthly, of a combination
of a steam generator, appliances for heating the air for the furnaces of the
generator and a feed-water heater in which the water is heated, by contact with
steam, to, or nearly to, the temperature of the boiling point; fifthly, of improved
apparatus and appliances for heating the air for the furnaces of steam gene-
rators. In order to secure more perfect combustion, to lessen the labour of
stoking, and at the same time to obviate or reduce the production of smoke, Í
arrange for the complete gasification of the fuel in a gas producer which forms
part of the boiler, instead of being external to it as in all the arrangements
hitherto proposed. This internal gas producer may be arranged in many ways,
and in connection with many varieties of boilers, but a description of its appli-
cation to the boiler described in my Specification No. 15721 dated 16th July 1896,
will enable its application to other types of boiler to be readily understood. In
its simplest form my improved boiler consists of two upper and two lower drums
placed parallel to each other at suitable distances apart, and provided with
suitable downcomers," which may be either internal or external. The up-
comers consist firstly, of two walls of tubes each connecting an upper drum
with its corresponding lower one. The tubes in each of these walls are placed
close together and the space between the two walls forms the gas producer.
The ends of this space and of the whole boiler, may be built up of fire-brick, or
of lubes forming part of the boiler; secondly two outer walls of tubes, each con-
necting its upper drum with its corresponding lower drum. The tubes in each
of these walls are placed at very small distances apart in order that the products
of combustion may be divided into thin sheets as they pass between the tubes.
The spaces between the inner and the outer walls form combustion chambers.
The gases from the producer flow into these combustion chambers where they
are mixed with air and burned. A combustion chamber may also be formed
within the gas producer, air being supplied to this space in order that partial
combustion may take place in this primary combustion chamber.
"
Xx
6
The fuel may be supplied to the gas producer through hoppers, or both the
supply of the fuel and the removal of the ashes may be accomplished by the use
of helical or other conveyors. The grate supporting the fuel in the producer
may consist of water tubes and form part of the boiler, or the grate may consist
of a channel shaped casting, the upper parts of the sides of the channel being
grid-like with the bars approximately vertical. The lower part of this channel-
shaped grate is submerged in water, and the ashes which collect in the bottom
of this channel are removed automatically by a worm working longitudinally in
this channel. In my improved arrangements for superheating the steam the
superheater is put in "parallel" with the whole or part of the ordinary boiler
heating surface, instead of being put in "series" with it as in other super-
heaters. A suitable valve is provided for regulating the amount of the hot pro-
ducts which flow through this "shunt circuit," and for stopping the flow alto-
gether when steam is not passing through the superheater. This valve may be
regulated by hand or automatically so as to cause a constant amount of super-
heating, or so as to vary the amount by which the steam is superheated in
accordance with the variations in the point of cut off in the steam engine cylinder.
In order to maintain the temperature constant to which the steam is super-
heated I place in the steam pipe, through which the steam passes from the
superheater, a tube closed at one end containing a suitable liquid, and outside the
steam pipe is fixed a corrugated diaphragm box which is in communication with
the internal tube containing the liquid. The liquid, or its vapour, presses on the
corrugated diaphragm and the motion produced by the changes in the fluid
pressure, due to changes in the temperature of the superheated steam, is mag-
nified by "lazy tongs" and transmitted to the superheater damper through a rod
or chain. In order to vary the temperature to which the steam is superheated

page_text: in accordance with the variations in the point of cut off in the steam engine I
employ a Knowle's supplementary governor, driven by the steam engine, to
vary the length of a chain attached to a lever on the damper spindle. When
the speed of the engine is varied one or the other of the two collars on the
rotating sleeve of the governor gears with and drives a friction pulley, on the
spindle of which is a worm which gears with a worm wheel. On the worm
wheel shaft is a chain pulley. When the load on the engine is varied, the
speed also varies and the friction wheel is driven in one direction or the other
until the engine speed becomes normal again. During this time the damper-
chain is being wound on to the chain wheel or unwound from it thus varying
the position of the damper.
The damper is arranged so that after maximum opening has been attained,
continued motion in the same direction will partially or entirely close it again.
The superheater may consist of a number of tubes or coils of tubing arranged in
parallel between suitable headers and so close together that the products of com-
bustion are divided into thin sheets in passing between the tubes. These tubes
may be flattened or elliptical in their transverse section and they may, prefer-
ably, be arranged with their major axes parallel to one another. In order to
raise the temperature of the feed water to, or nearly to, the temperature of the
boiling point, I cause it to flow in thin sheets or films over suitable surfaces
while it and they are exposed to steam at the full boiler pressure. These sur-
faces may preferably be roughened. In another modification the water is caused
to flow over sheets of wire gauze in order that it may be caused to spread into
thin films both sides of which are exposed to the steam. The feed water is
delivered from the feed pipe into an open-topped vertical cylindrical collecting
box, round the outside of which is wound a sheet of wire gauze which projects
above the top of the cylindrical collecting box. The water overflows from this
box and the wire gauze causes it to flow in the form of a thin film down the out-
side of the box. The water falling from this box is then collected by an inverted
cone consisting of, or lined with, wire gauze and from this inverted cone it is
delivered on to the vertex of an upright cone consisting of wire gauze. From
the circumference of the base of this come the hot water falls into a collecting
box, where any remaining sediment is deposited, and the water then flows to
and mixes with the other water in the boiler.
This apparatus may be placed in a vessel external to the boiler or it may be
placed in the steam drum of the boiler.
When it is placed within the steam drum I surround it by two concentric
casings, to both of which steam is freely admitted, with the object of preventing
the steam for the engines becoming wet before it leaves the boiler. In order to
heat the air required for the boiler furnaces, I employ an air heater consisting
of a number of parallel sheets of metal which may be either plane, embossed or
corrugated. These sheets are fixed within a casing at suitable distances apart
so that the spaces between them form flues or passages. Suitable ports aro
arranged near each end of these flues. The products of combustion, after leaving
the boiler, flow through every alternate flue or passage, and the air on its way
to the boiler flows through the other alternate flues in this air-heater, and thus
has its temperature raised by the heat abstracted from the products of combus-
tion.
Instead of building the air-heater of sheets as described above, I may build
it of flattened tubes, fixed between tube plates. These tubes may have their
sides either plane, embossed or corrugated. When the flues of the air-heater,
built up in either of the above ways, are plane, I arrange a number of transverse
diaphragms in these flues in order to greatly reduce the flue area where they
are fixed; with the object of causing more rapid mixing of the products of
combustion and of the air in their respective flues. In another modification I
arrange to heat the air in the casing of the boiler, which is for this purpose
made double, and which is built up of corrugated sheets with the object of

page_text: 'causing more rapid interchange of heat between the products of combustion and
the air.
The nature of my invention will be better understood on reference to the
accompanying sheets in which the same letters refer to similar parts throughout
the several views. The two figures on Sheet I represent one form of my improved
steam generator. Figure 1 is a transverse section. Figure 2 is a side elevation,
from a part of which the outside casing is removed. In Figure 1 each of the
two upper drums D, D' is connected to one of the two lower drums d, d by a
longitudinal row of down-comer tubes t, t¹ the tubes in these longitudinal rows
being placed at suitable distances apart; and by four rows of upcomer
tubes to, t t t The tubes in the two inner rows i̟ and i̟ form walls of the
gas producer, P, and the tubes in these two rows are quite close to-gether,
excepting near their ends where the tubes are either of a smaller diameter or
each alternate tube is bent to a different angle, as shown with the object of
- enabling the tubes to be expanded into the drums without unduly weakening
the drums, and, at the upper ends with the additional object of providing pas-
sages between the tubes for the flow of the gases from the gas producer into the
combustion chambers c, c'. The spaces thus left between the tubes at the lower
ends are closed by suitable diaphragms so as to prevent the flow of air between
the tubes at these ends. The tubes in the two rows t₂ and t, are fixed at very
small distances apart with the object of causing the products of combustion to
be divided into very thin sheets as they flow out of the boiler into the external
flues f&f formed between the outer rows of tubes and the boiler casing e, el.
The products of combustion flow along these external flues to the uptake 1,
Figure 2, at one end of the boiler. The fuel is fed into the gas producer
through the hopper r, which may be of refractory material, or of metal. In the
latter case the walls of the hopper are hollow in order that it may be kept cool
either by a flow of water or of air through it. The fuel may be fed into the gas
producer either by hand or by a helical conveyor of the type usually used in
connection with mechanical stokers, a suitable lock being provided to prevent
air flowing in or gas flowing out. The air & steam for the gas producer enter
it between the grate bars g, g¹. The ashes are removed from the bottom of the
gas producer either by hand or by a worm of ordinary construction. The air
for the combustion of the gas flows into the combustion chamber from the air
boxes A, A as indicated by the arrows. Baffles of refractory material F, F
are provided with the object of causing the flames to flow downwards through
the combustion chamber as indicated by arrows. My improved arrangements
for superheating steam are illustrated as applied to a Lancashire boiler by
Figures 3, 4 and 5, Sheet II, and as applied to an ordinary marine boiler by
Figures 6, 7 and 8 Sheet III. In the case of a Lancashire boiler Sheet II a
portion of the products of combustion pass from the "downtake" chamber at
the rear end of the boiler, B, direct to the superheater and the amount of pro-
ducts passing through this shunt circuit is regulated by the superheater
damper N. The direction of flow of the products of combustion is clearly shown
by the arrows. The steam from the boiler enters one compartment of the
header h, flows through the U shaped tubes of the superheater and then passes
into the other compartment of the header, from which it flows to the engine.
The tubes are expanded into the header and in order that this may be done
without unduly weakening.it the tubes have their ends drawn down to a reduced
diameter or each alternate has its ends sufficiently bent for the purpose. In
the case of a marine boiler, illustrated on Sheet III., a portion of the products
of combustion is withdrawn from each combustion chamber through the tubes t,
Figures 6 and 7.
The superheater damper is shown at, N, and the products of combustion after
passing through it flow by means of the supplementary flue, f, to the main
uptake of the boiler.

page_text: Figures 9 and 10, Sheet IV., illustrate my arrangements for automatically
regulating the degree of superheat given to the steam."
Fig. 9 shows how the temperature to which the steam is superheated is main-
tained approximately constant. The tube placed in the header of the super-
heater contains a liquid and the variations in the pressure of this liquid, or of
its vapour, due to variations in the temperature of the steam, cause the corru-
gated diaphragm, b, to be more or less deflected. The motion of the corrugated
diaphragm is magnified by the "lazy tongs," 1, the point, p, of which is fixed,.
and by means of suitable links this motion is transmitted to the superheater
damper N. Fig. 10 shows how the temperature of the superheated steam may
be varied in accordance with the variations in the point at which the steam is
cut-off in the engine cylinder. The main governor, G, varies the travel of the.
slide valve in the usual way and the supplementary governor, G¹, besides
restoring the speed to its normal speed after each change in the load on the
engine also determines the position of the superheater damper N. When the
speed of the engine varies from the normal speed one or other of the two collars
on the governor sleeve gears with the friction wheel, W, thus rotating it in one
direction or the other. The worm W, drives the worm wheel, W₁, and during
this time the superheater damper-chain is being wound on to the chain wheel, W,
or being unwound from it and in this way the position of the damper is modified
in accordance with the new point of cut off in the engine. Figs. 11, 12 and 13,
Sheet 5, show one form of my air-heater as applied to a marine boiler. The
corrugated sheets of which the heater, H, is built up, are kept at suitable dis-
tances apart by cast or forged pieces of metal m, n, one of which is shown
separately by the two views of Fig. 14, Sheet 5. The vertical distance pieces
are plane and the horizontal ones are corrugated. The spaces thus formed
between the corrugated sheets are the passages through which the air and the.
products of combustion flow, in the directions indicated by the arrows. The air
Hows through every alternate passage and the products of combustion flow
through the other passages. The corrugated sheets and their distance pieces are
either bolted or rivetted to gether. The air after being heated in the heater
flows through the ducts d to the boiler furnaces.
3
Fig. 15 Sheet 6 shows one form of my feed water heater attached to the end
of a boiler B. The cylindrical containing vessel V is attached to the boiler as
indicated and when the apparatus is in action there is free communication
between this cylindrical vessel and the boiler, by means of the two passages J
and J. The steam for heating the feed water flows from the boiler through the
passage into the heater and the hot feed water flows from the heater through
the passage into the boiler.
The sediment is removed from this vessel by taking off the cover K and in
order that this may be done while the boiler is under steam pressure screw
down valves, not shown, are provided in the passages J, J. A gauge glass for
showing the level of the water in the heater is fixed to the vessel V but this is
not shown in the drawing.
The feed water to be heated is delivered by the pipe L into the cylin
drical box, M, round the outside of which is wound a sheet of wire gauze, indi-
cated by the wavy lines. The water overflows from this box and the wire gauze
causes it to flow in the form of a thin film down the outside of the box. From
the bottom of the box the water flows on to the inverted cone, 7, of wire gauze,
down which it flows and from which it is delivered on to the cone Q, which is
also of wire gauze. The base of the come Q is above the level of the water in
the vessel V so that steam is freely admitted to the insides of the cones.
Fig. 16, Sheet 6, shows the feed water heating apparatus as arranged when
it is placed inside the boiler. The action is the same as just described for the
external arrangement.
The heated water falling from the cone Q is collected in the box M³ so that
the sediment may be deposited within it. From this box M¹ the water over-

page_text: flows by the central passage, y, and then mixes with the water in the boiler.
The two open ended concentric cylinders and prevent the steam for the
engines becoming wet before it leaves the boiler. The apparatus is supported
within the boiler in any suitable manner.
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 steam generator the arrangement and combination of parts consisting
of a steam generator and an internal gas producer in the manner and for the
purposes substantially as herein described and illustrated.
2. In a steam generator the arrangement & combination of parts consisting
of steam & water drums connected by walls of tubes comprising an internal
gas producer and combustion chambers, together with the arrangements for
supplying the air to the combustion chambers and the arrangements for sup-
plying the fuel & removing the ashes in the manner & for the purposes substan-
tially as herein described and illustrated.
3. In a steam generator consisting of walls of tubes or concentric coils of
tubing with an internal gas producer and combustion chambers together with
the arrangements for supplying the fuel and removing the ashes in the manner
& for the purposes substantially as herein described.
4. The arrangement & combination of parts consisting of a steam generator
combined with a superheater in such a way that the superheater is put in
"parallel circuit" with a part or the whole of the boiler heating surface and
arranged so that the flow of the products of combustion through this shunt
circuit may be regulated or prevented in the manner & for the purposes sub-
stantially as herein described and illustrated.
5. In connection with steam superheaters the arrangement and combination
of parts for automatically regulating the flow of the products of combustion
through the superheater in such a way as to maintain the temperature to which
the steam is raised approximately constant, in the manner & for the purposes
substantially as herein described & illustrated.
G. In connection with steam superheaters the arrangement and combination,
of parts for automatically varying the temperature to which the steam is super-
heated in accordance with the variations in the point at which steam is cut off
in the engine in the manner & for the purposes substantially as herein described
and illustrated.
7. In connection with steam generators the arrangement and combination of
parts for raising the temperature of the feed water to, or nearly to, the tempera-
ture of the steam in the manner & for the purposes substantially as herein
described.
8. The arrangement and combination of parts for heating the air for steam
boilers by means of an air heater constructed in the manner and for the pur-
poses substantially as herein described.
9. The arrangement and combination of parts for heating the air for steam
boilers within a double casing of the boiler such casing being constructed of
corrugated sheets of metal in the manner and for the purposes substantially as
herein described.
10. The arrangement and combination of parts consisting of a steam gene-
rator, appliances for heating the air for the furnaces of the generator and a feed
water heater in which the water is heated, by contact with steam to, or nearly to,
the temperature of the boiling point in the manner and for the purposes sub-
stantially as herein described.