IMPROVEMENTS IN AND RELATING TO STEAM GENERATORS AND FURNACES THEREFOR
Year: 1882

page_text: LETTERS PATENT to William Phillips Thompson of the Agency for Foreign
Patent Solicitors 6 Lord Street Liverpool in the County of Lancaster and
of 323 High Holborn in the County of Middlesex Civil Engineer for an
Invention of "IMPROVEMENTS IN AND RELATING TO STEAM GENERATORS AND
FURNACES THEREFOR Communicated to me from abroad by Mauricio. M.
Monsanto, Benjamin Odio and Felipe Perozo all of the City, County and State
of New York United States of America.
PROVISIONAL SPECIFICATION left by the said William Phillips Thompson
at the Office of the Commissioners of Patents on the 29th September 1882.
WILLIAM PHILLIPS THOMPSON of the Agency for Foreign Patent Solicitors
6 Lord Street Liverpool in the county of Lancaster and of 323 High Holborn
in the County of Middlesex Civil Engineer "IMPROVEMENTS IN AND RELATING TO
STEAM GENERATORS AND FURNACES THEREFOR a communication to me from
abroad by Mauricio M. Monsanto, Benjamin Odio, and Felipe Perozo all of the city
county and state of New York, United States of America:
"
The general features of this boiler or steam generator are as follows:
Above the grate surface and furnace proper we introduce a supply of air in a
sub-divided condition, by means of slots or perforations which air upon being
brought into contact and intermingled with the imperfectly combined and partially
consumed gases emanating from the furnace, causes a perfect combustion thereof.
It is generally agreed that none of the various kinds of boiler furnaces heretofore.
known consume the fuel perfectly and that the approximate consumption depends
more or less upon the mode of firing, or the thickness of the layer of buruing coal
on the grates, on the supply of air, on the intensity of the draught and on many
other contingencies. The quantity of fuel thus wasted by imperfect conditions is
very considerable.
In all furnaces the air in its passage through the interstices of the grate, comes
into contact and combines with the fuel next the bars, forming carbonic acid, but

page_text: 1
as these gases pass through the upper layer of incandescent fuel they deliver part
of their oxygen to the latter, and the result is but partial combustion, leaving the
carbonic acid transformed into carbonic oxide, as in the gas furnace (Siemens for
example) This gas is found in greater or less quantity among the waste gases from
all steam boiler furnaces. This carbonic oxide becomes very inflammable when
brought in contact and intermingled with air, at the requisite temperature that of
the point of ignition. Hence if the intermingling of air is caused to occur at a
point above the layer of incandescent coals, where the temperature is at the highest,
we shall effect the combustion and employment of this gas which would otherwise
be but partly utilized, and as a result obtain greater heat and a corresponding
economy of fuel.
The very large combustion chamber above the furnace has the effect of very
greatly facilitating the intimate mixture of the gases and air, and allows the
necessary time for the chemical union of combustion to be effected before springing
into flame. This operation furthermore is performed before the gases come into
contact with the heat absorbing surface, or heating surface of the generator thereby
avoiding the pernicious effect of cooling the products of the combustion below the
igniting temperature.
The heating surface of this generator is formed of a nest of concentrical coils
forming a series of frustrums of cones or of pyramids, their bases being about the
size of the grate, and resting on a plate above the grates which protects the lower
turns of the coils from the intense heat of the furnace as it rises from the grates.
They are covered above by a baffle plate or deflector whose convex side is toward
the coils. These coils are set within a conical shell forming a large chamber
for the combustion of the fuel. As the heat rises vertically from the grate it
strikes the baffle plate and is deflected sideways and impinges upon the tubes com-
posing the coils. The nest of coils together with the furnace are covered by a
single or double outside conical casing of iron or brickwork, which leads the gases
to the smoke flue or stack.
One of the most essential points of a steam generator, namely, the effective and
economical generation of heat and its application to the absorbing surface, is well
covered in this device.
The heat absorbing medium in all steam generators is water, the body of greatest
specific heat. In many cases in generators where there is a defective circulation,
steam becomes substituted for water in the tubes, and, as is well established, their
respective heat absorbing qualities are very unequal, in favor of the water, and
where steam takes the place of water the metal is over-heated and suffers premature
decay.
The quantity of heat transmitted in a given time depends upon the difference
between the temperature of the imparting heat, and that of the water, corresponding
to the steam pressure carried by the generator. Thus at a given steam pressure
the water will absorb the more heat the nearer it be placed at right angle over the
focus of the greatest intensity of the furnace.
In this generator all of the heat absorbing surface is directly exposed at right
angle or nearly so to the heat of the furnace at its greatest intensity and the result
is the greatest heat absorption.
The absorption of heat depends also upon the contact of the water with the heat
conducting medium. This cannot be obtained save by the perfect circulation of
the water, as heat is transmitted to liquids by connection or carried from one place
to another by currents. When one atom of water in contact with the conducting
medium absorbs heat, it becomes specifically lighter than the surrounding atoms
and tends to rise, but will be prevented from rising if another colder atom is not
present to take its place. In such case the water becomes superheated, and, if
space be allowed it for expansion will turn into steam, steam then and not water
will be in contact with the heating surface. This is the action which occurs in
those forms of generators in which the circulation is defective. In this generator
each one of the nest of coils is independently connected, both above and below, to a

page_text: standpipe carrying the steam above the coil connections and the mud receptacle or
drum below.
This standpipe is removed from the direct influence of the heat from the grate,
and rises higher than the coils or baffle plate and extends below the lower coil
connections.
As the heat impinges on the coils, the water therein becomes heated and
specifically lighter than that contained in the stand-pipe. The water level being
above the upper coil connections, the difference in the specific gravity of these two
columns of water causes a circulation, the warm current tending upward within
the coils, and the cooler or cold current tending downward in the standpipe.
The difference of the respective weights of these two columns of water being in
favor of the cold or cooler current, gives to this downward current a hydrostatic
head, which tends to further and increase the upward tendency of the water in the
coils, and in fact, not only takes its place, but tends to dislodge it by force.
The peculiar construction of the coils, also tends to facilitate circulation.
The inner coil is smaller than the enveloping ones and contains less heating.
surface the others in turn increase in diameter and area, but as the inner coil is
exposed to a more intense heat than the enveloping coils and they in turn are
exposed to less and less heat their respective heat absorbing capacities are more or
less equalized, and the inner coil being made with a greater distance between the
turns than the subsequent ones, the difference mentioned is not only thereby
augmented, but the velocity of the circulating column of water is greatly accelerated
in the inner coil on account of its greater pitch; more so than in the others. The
area of the tubes of the coils also increases in size from below upwards having an
inlet for water at their lower point of connection with the standpipe smaller than
the outlet at the upper point of connection; by this means the friction of the
upward current is diminished and the water given facilities for expansion; thus
the water is delivered to the standpipe with very nearly the same velocity as at
the inlet notwithstanding its increased temperature and pressure. The water in
circulation therefore travels unimpeded. When the superheated water or steam
and water arrive from the upward current into the standpipe the steam disengages
itself from the water and rises into the steam dome whilst the water returns.
downward together with the feed water for further circulation. The standpipe
has about ten to twenty times the area of all the coils, in order that the downward
current may travel at about one twentieth of the speed of the upward. So if the
water of the upward current loses one half in the form of steam, the downward
current will travel twice as slow again. The water on arriving at the stand pipe
will by this means find a moment of repose before starting on its downward course.
This moment of repose or slow descent allows the steam the necessary time for its
disengagement from the water and ensures a perfectly dry steam and a steady
water level.
The generality of steam boilers give a very wet steam, containing sometimes as
high as 50 per cent of water, which not alone renders the steam very ineffective and
very much more liable to condensation, but increases in proportion, the consumption
of fuel.
Another feature of this invention is the separation from the water, of those
impurities which form scale, and the preventing of those impurities from settlement
upon the interior surface of the coils, by means of the circulatory currents, and
the favorable situation of the mud drum, thus enabling the use of water of any
quality. The very slow downward travel of the water in the stand pipe allows the
time necessary for the decantation or subsidence of the impurities. As they become
separated from the water they are carried by force of gravity to the bottom of the
standpipe from whence they may be removed by means of a blow off cock. When-
ever convenient a deflector is placed in the stand pipe in front of the inlets of the
supply coils and thus oblige the water to descend to the mud drum before ascending
to the supply coils, thereby causing a more perfect subsidence of the impurities
and depuration of the water..

page_text: Another feature of the invention is its freedom from explosion: The water level
being high up at the stand pipe and much above the level of the coils within the
boiler shell no danger will result in the lowering of this water level from neglect or
oversight of the engineer, as the coils will always be full of water, and although
the higher the water level the better the circulation and the greater the efficiency
of the generator, no actual danger can accrue even if the water be below the top
of the coils, as in such case the water in the lower part of the coils will be
evaporating and the steam from it will be cooling off the upper exposed parts of
the coils, where it will become superheated. This condition of things will not be
dangerous but simply uneconomical.
To attain these ends well known elements are employed which have hitherto
been arranged, employed and combined in various ways, and with other novel
features some of these elements and arrangements with relation to each other are
made use of as will more particularly appear hereinafter.
The exterior enclosing shell of the generator is made double. An opening is
provided at the upper end of the generator through which air may enter into the
hollow shell to pass downward an I have its exit into the ash pit beneath the grate.
A suitable valve may be there provided to regulate the admission of air through
the hollow double shell.
The air is drawn downward by the draught of the boiler and enters beneath the
fire box. A certain amount of air likewise enters through holes or slots at the side
of the fire box. The air in its downward course becomes heated by contact with
an inner shell and thus affords a hot blast to the fuel. Within the generator shell
are several spiral coils which are arranged in conical form, one within another, and rest
upon an inclined supporting plate whose inner concave side is toward and within
the furnace and whose convexity is in the outer or ashpit side. This supporting
plate being also designed to protect the lower turns of the pipe coils from the
intense heat of the furnace. The inner coil preferably should have a greater
distance between its contiguous turns than the outer ones thereof, giving a greater
pitch and insuring a quicker circulation. These series of coils communicate by
pipes with an outside horizontal mud drum or chamber that together form in effect
an outside stand pipe and the extremities of the coils communicate by pipes with
an internal steam drum. Steam escapes from this drum through a perforated tube.
This steam drum is strengthened longitudinally by a central brace. Below this
steam drum and crossing the coils is located a deflector or baffle plate of convex
form lowest at the centre and rising laterally. A water gauge communicates with
the steam drum.
The water should constantly be maintained above the level of the pipes.
The steam drum is likewise provided with a drain pipe.
Water can be forced into the mud chamber or drum through a feed pipe and a
blow off pipe is attached to said drum by which it may be emptied. A fuel.
reservoir may be used in connection with the generator in order that the fuel may
be automatically fed to the furnace on the base burning plan.
-
The operation of the apparatus may be readily understood.
A fire having been kindled in the fire box, the products of combustion pass
upward impinging against the inner coil pipes and are thence deflected outward
through and between the other coils, escaping upward past the deffector or baffle
plate and thence escaping by a chimney. The heat travelling vertically and being
deflected by the baffle plate, laterally at right angles to the heating surface, the
upper turns of the coils are impinged upon with greater intensity of heat than the
lower turns, thus the water is being gradually heated in its ascent in the cuils,
favoring thereby circulation and making it impossible for the water to recede
backward through the stand pipe to steam chamber.
The inner shell will be heated somewhat by the products of combustion and the
air passing downward through the hollow shell will abstract heat therefrom and
enter the tire box in a hot condition, thereby ensuring a more perfect combustion of
the fuel. The water in the coils becoming heated ascends in different ascending,

page_text: currents creating a rapid interior circulation. The water in the lower part of the
drum descends through pipes and enters the mud chamber or drum and thence
returns to the bottom of the coils maintaining thus a constant circulation. As a
result it will be found that this generator will produce a large amount of dry steam
in proportion to the fuel consumed. The invention may be modified so that the
steam drum may be in effect the upper part of the stand pipe, and its lower part in
effect a mud drum; and when the boiler is in operation the hydrostatic pressure of
the water within the standpipe being greater than that within the heating coils
causes and maintains a constant circulation of water through the said coils:
coils through which the feed water may be introduced may also be independent of
the generating coils. A plate is then used to cover the junction of the return
pipes, with the stand pipe so as to cause the water to descend below the lower edge
of the plate before entering the pipes. By this means a more perfect deposit of
sediment is obtained.
A hand hole is provided for the removal of such sediment.
+
1}
The
The coils increase in diameter from the bottom upward so that as the water is
gradually converted into steam in its tipward movement more space is allowed
thereby ensuring a more perfect circulation:
For marine purposes where the rocking motion of the vessel will diminish or
reverse the pitch of the coils, check valves äre placed between the lower coil
connections and the stand pipe for the purpose of preventing the retrocession of
the water in the coils and the lifting thereby of the water in the stand pipe
towards the steam drum which may be caused by the intermittent motion of the
vessel.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Phillips Thompson in the Great Seal Patent Office on the
29th March 1883.
"
WILLIAM PHILLIPS THOMPSON, of the Agency for Foreign Patent Solicitors,
6, Lord Street, Liverpool, in the County of Lancaster, and of 323, High Holborn, in
the County of Middlesex, Civil Engineer IMPROVEMENTS IN AND RELATING TO
STEAM GENERATORS AND FURNACES THEREFOR."-A communication to me from
abroad by Mauricio M. Monsanto, Benjamin Odio, and Felipe Perozo, all of the city,
county and state of New York United States of America.
The invention has for its object an improvement in the construction of boilers
for the generation of steam, the distillation of liquids, the evaporation of saline or
saccharine liquids and other similar applications of heat, together with improve-
ments in the construction of boiler furnaces and combustion chambers for the more
economical burning of fuel, pulverized or otherwise, bituminous or coking coals,
anthracite, semi-bituminous andcannel coals, or the various hydrocarbons and other
gases. A further object is to provide an improved setting and arrangement of the
flues and passages of such boilers and furnaces.
The very successful introduction of compound engines for marine and for
portable or stationary services, and the great economy of fuel obtained by the
application of very high pressures of steam, has called loudly for a safe and reliable
steam boiler which shall guarantee these advantages.
To-day it is theoretically and practically demonstrated and confirmed, that the
higher the steam pressure, the greater the ratio of steam expansion and consequently
the greater the economy of fuel.
To prove this assertion it is needful but to recall the recognized facts well known
by engineers that a large quantity of heat is required to raise the water to the boiling
point, that a still greater quantity in the insensible or latent form is required to
convert it into steam at the atmospheric pressure, that in this condition steain
147 pounds total pressure per square inch contains 1146 degrees Fahrenheit of total
heat, while for practical purposes of motive power it is valueless, that we require for
this purpose a pressure above that of the atmosphere. Now to generate steam of
30 pounds above atmospheric pressure containing 274 degrees sensible beat, we
require to transmit to the water, from heat generated within the furnace,
1165 degrees of heat being the correspondent total heat contained in that quantity
of steam, to generate 100 pounds of steam of guage pressure of 338 degrees
temperature, we require an absorption of 1184 degrees of heat; for 200 pounds
pressure of 388 degrees sensible beat we require 1200 degrees total heat, for
500 pounds pressure of 468 degrees temperature, 1249 degrees total heat.
The above data demonstrate that very little total heat absorbed after the boiling
point of water has been obtained, raises the pressure of the steam extraordinarily,
whilst there is no further transformation than that with a higher pressure the
sensible heat augments at the expense of the latent heat.
But there is within the furnace upwards of 2000 degrees of heat generated by
the fuel, which is more than amply sufficient to give the amount of available heat,
to generate steam of the highest pressures, if this heat be applied before its
intensity is diminished by expansion and radiation or impingement upon other
bodies which will absorb heat without ultimate utility to steam generation; for it
might be taken for granted (taking into consideration the small amount of excess
of heat required to considerably augment the steam pressure) that the same
quantity of fuel will generate a certain quantity of steam at whatever pressure,

page_text: whereby it will be augmenting one of the components of power-the pressure
without extra cost.
A boiler of the required conditions has not, up to date, been constructed to safely
carry even a greater pressure than that ordinarily now in use. Let us survey the
systems employed at present.
..
The system of tubular or multi-tubular boilers (that is the system in which the
heated gases pass through the inside of the flues or tubes, the water circulating on
the outside) would for very high steam pressure call for a thickness of shell
incompatible with the present practical facilities of manufacture.
Besides this deficiency in pressure resisting power, it is well known that the
tubes of tubular boilers, horizontal or vertical, act like a "Davy's safety lamp,
cooling the products of combustion and extinguishing the flame, so that if perfect
combustion has not been effected before the products are carried by the draught
through the tubes no further combustion can take place, giving thereby a negative
economical result and depositing soot on the heating surfaces.
To obtain the desired results, engineers have looked forward, as the only solution
of this problem, to the so called water tube, the tubular or sectional boiler, that is
the type of the system by which the cylindrical portions which are subjected to the
internal pressure are greatly reduced in diameter augmenting proportionately
their resistance, and increased in number, offering thereby the necessary heating
surface for the absorption of the heat, and reducing greatly the thickness of the
metal walls of the tubes; giving thereby a greater facility for the transmission of
heat to the water.
This type of boilers with straight, horizontal, or slightly inclined water tubes,
has not given those practical results especially for high pressure, which were
expected of them, principally on account of the want of proper facilities for the
circulation of the boiling liquid.
The steam generated in these horizontal or nearly horizontal tubes has no facility
of outlet except through the headers or vertical channel ways at the ends of the
tubes, and as steam cannot ascend or travel horizontally by reason of its lighter
specific weight over the water, it will consequently remain more or less stagnated
within the tubes, becoming there superheated and forcing, by its excess of expansive
power, its way through the headers.
On arriving at these vertical channel ways the steam of comparatively higher
pressure shoots upward with great rapidly encountering in its way the downward
current of the water. These two currents have a struggle for supremacy which is
further augmented by the friction created by the corresponding violence exercised
by them in their opposite actions whereby circulation is totally impeded; or the
steam predominating must take along with it the water of the downward current,
giving by this intermittent action, very wet steam on the one side and leaving the
boiler tubes empty to perish in the flame.
As horizontal tubes give no facility for the disengagement of the steam atoms,
on their being generated, this defect being augmented by the great length of the
tubes with which large boilers have to be supplied so as to aggregate the required
heating surface, it follows that proportionately the larger the boiler the less
effective and economical it is, and the more exposed to deterioration. The exposure,
in a boiler, of the water and steam in a nearly stagnant condition to the intense.
heat of the furnace, exposes also the impurities of the water, which form the boiler
scale, to be burnt into the inner surface of the tubes, making the latter daily less
and less effective and more and more dangerous. It is a very weak point of all of
this style of boiler constructions, that a comparatively very small portion of the
heating surface is exposed to the greatest intensity of the heat generated by the
fuel-that of the furnace proper-where there exists with good combustion upwards
of 2000. degrees of heat; whilst this intense heat is otherwise limited by its
expansion and radiation to comparatively ineffective parts of the boiler when it
really comes to act on the greater bulk of the heating surface,
This defect is. the more striking,.if the boiler is designed for bigh pressures of

page_text: steam, where as great a difference as possible between the temperature of the
furnace and the absorbing capacity of water, at a high temperature, are most
desirable and indispensable.
The system of steam generators denominated "forced circulation” “ "injection "
or "flash" boilers, of which there are several in the market relate to quick steaming
boilers wherein the feed water is injected from above or from below upon the
heating surface-which is generally made of tubes-into the one end of which enters
the water and out of the other end of which the steam is drawn, and thence directly
communicated to the engine. The heating surface is consequently more exposed
and superheated steam being the heat absorbing medium instead of water-the
result is a premature deterioration and decay of the metal which makes these
boilers unreliable and of short life.
In such steam generators, all the working functions depend on the quantities of
water injected, consequently on the efficiency and regularity of the feed pump. The
more water injected the less steam will be generated and vice versa, and the higher
the steam pressure the greater the exposure of the whole boiler to the deteriorating
effects of the intense heat.
Besides the above inconveniences or defects, this style of boiler requires indis-
pensably very pure water, as all impurities separated from the water used are
inevitably deposited within the tubes or coils as they have no possible outlet.
In this invention the highest pressure possible is obtained, combined with a very
large margin of safety, perfect combustion, and in consequence thereof greatest
economy of fuel. The prevention of the deposit of those impurities which form scale
upon the interior surfaces of the generator: the exposure of all the heating surface to
the direct action of the intense heat from the furnace without choking, and after
the combustion has been effected within a large combustion chamber, lighter weight
and compactness, reducing cost and space required for the accommodation of the
generator, and increasing transportability, obviating all the defects of other forms
of generators and embodying numerous new and very important features.
The general features of this boiler or steam generator are as follows:-
Above the grate surface and furnace proper is introduced a supply of air in a
subdivided condition, by means of slots or perforations which air, upon being
brought into contact and intermingled with the imperfectly combined and partially
consumed gases emanating from the furnace, causes a perfect combustion thereof.
It is well settled that none of the various kinds of boiler furnaces heretofore known
consume the fuel perfectly, and that the approximate consumption depends more or
less upon the mode of firing, or the thickness of the layer of burning coal on the
grates, on the supply of air, on the intensity of the draught, and on many other
contingencies. The quantity of fuel thus wasted by imperfect conditions is very
considerable.
In all furnaces the air in its passage through the interstices of the grate, comes
into contact and combines with the fuel next the bars, forming carbonic acid, but
as these gases pass through the upper layer of incandescent fuel they deliver part
of their oxygen to the latter, and the result is but partial combustion, leaving the
carbonic acid transformed into carbonic oxide, as in the gas furnace (Siemens for
example). This gas is found in greater or less quantity among the waste gases
from all steam boiler furnaces. This carbonic oxide becomes very inflammable when
brought in contact and intermingled with air, at the requisite temperature-that
of the point of ignition. Hence if we cause the intermingling of air to occur at a
point above the layer of incandescent coals, where the temperature is at the highest,
we shall effect the combustion and employment of this gas which would otherwise
be but partly utilized, and as a result obtain greater heat and a corresponding
economy of fuel.
The very large combustion chamber above the furnace has the effect of very
greatly facilitating the intimate mixture of the gases and air, and allows the
necessary time for the chemical union of combustion to be effected before springing
into flame. This operation furthermore is performed before the gases come into

page_text: contact with the heat absorbing surface, or heating surface of the generator thereby
avoiding the pernicious effect of cooling the products of the combustion below the
igniting temperature.
The heating surface of the generator is formed of a nest of concentrical coils
forming a series of frustrums of cones or of pyramids, their bases being about the
size of the grate, and resting on a plate above the grates which protects the lower
turns of the coils from the intense heat of the furnace as it rises from the grates.
They are covered above by a baffle plate or deflector whose convex side is toward
the coils. These coils are set within a conical shell forming a large chamber for
the combustion of the fuel. As the heat rises vertically from the grate it strikes
the baffle plate and is deflected sideways and impinges upon the tubes composing
the coils. The nest of coils together with the furnace are covered by a single or
double outside conical casing of iron or brickwork, which leads the gases to the
smoke flue or stack.
One of the most essential points of a steam generator, namely, the effective and
economical generation of heat and its application to the absorbing surface, is well
covered in this device.
The heat absorbing medium in all steam generators is water-the body of
greatest specific heat. In many cases in generators where there is a defective
circulation, steam becomes substituted for water in the tubes, and, as is well
established, their respective heat absorbing qualities are very unequal, in favor of
the water, and where steam takes the place of water the metal is overheated and
suffers premature decay.
The quantity of heat transmitted in a given time depends upon the difference
between the temperature of the imparting heat, and that of the water corresponding
to the steam pressure carried by the generator. Thus at a given steam pressure the
water will absorb the more heat the nearer it be placed at right angle over the focus
of the greatest intensity of the furnace.
In this generator all of the heat absorbing surface is directly exposed at right
angle or nearly so to the heat of the furnace at its greatest intensity, and the result
is the greatest heat absorption.
The absorption of heat depends also upon the contact of the water with the heat
conducting medium. This cannot be obtained save by the perfect circulation of the
water, as heat is transmitted to liquids by convection or carried from one place to
another by currents. When one atom' of water in contact with the conducting
'medium absorbs heat, it becomes specifically lighter than the surrounding atoms
and tends to rise, but will be prevented from rising if another colder atom is not
pres to take. its place. In such case the water becomes superheated, and, if space
be allowed it for expansion, will turn into steam; steam then and not water will
be in contact with the heating surface. This is the action which occurs in those
forms of generators in which the circulation is defective. In this generator
each one of the nest of coils is independently connected, both above and below,
to a standpipe carrying the steam above the coil connections and the mud receptacle
or drum below.
.
This standpipe is removed from the direct influence of the heat from the grate,
and rises higher than the coils or baffle plate and extends below the lower coil
connections.
As the leat impinges on the coils, the water therein becomes heated and
specifically lighter than that contained in the stand pipe. The water level being
above the upper coil connections, the difference in the specific gravity of these two
columns of water causes a circulation, the warm current tending upward within
the coils, and the cooler or cold current tending downward in the standpipe.
The difference of the respective weights of these two columns of water being in
favor of the cold or cooler current, gives to this downward current a hydrostatic
head, which tends to further and increase the upward tendency of the water in the
coils, and in fact, not only takes its place, but tends to dislodge it by force.
The peculiar construction of the coils, also tends to facilitate circulation.

page_text: The inner coil is smaller than the enveloping ones and contains less heating
surface, the others in turn increase in diameter and area, but as the inner coil is
exposed to a more intense heat than the enveloping coils and they in turn are
exposed to less and less heat, their respective heat absorbing capacities are more or
less equalized, and the inner coil being made with a greater distance between the
turns than the subsequent ones, the difference mentioned is not only thereby
augmented, but the velocity of the circulating column of water is greatly
accelerated in the inner coil on account of its greater pitch; more so than in the
others. The area of the tubes of the coils also increases in size from below upwards,
having an inlet for water at their lower point of connection with the standpipe
smaller than the outlet at the upper point of connection; by this means the
friction of the upward current is diminished and the water given facilities for
expansion; thus the water is delivered to the standpipe with very nearly the same
velocity as at the inlet notwithstanding its increased temperature and pressure.
The water in circulation therefore travels unimpeded. When the superheated
water or steam and water arrive from the upward current into the stand-pipe the
steam disengages itself from the water and rises into the steam dome whilst the
water returns downward together with the feed water for further circulation. The
standpipe has about ten to twenty times the area of all the coils, in order that the
downward current may travel at about one twentieth of the speed of the upward.
So if the water of the upward current loses one half in the form of steam, the
downward current will travel twice as slow again. The water on arriving at the
stand-pipe will by this means find a moment of repose, before starting on its
downward course. This moment of repose or slow descent allows the steam the
necessary time for its disengagement from the water and ensures a perfectly dry
steam and a steady water level.
The generality of steam boilers give a very wet steam containing sometimes as
high as 50 per cent of water, which not alone renders the steam very ineffective
and very much more liable to condensation, but increases in proportion, the
consumption of fuel.
Another feature of this invention is the separation from the water, of those
impurities which form scale, and the preventing of those impurities from settlement
upon the interior surface of the coils; by means of the circulatory currents, and
the favorable situation of the mud drum, thus enabling the use of water of any
quality. The very slow downward travel of the water in the standpipe allows
the time necessary for the decantation or subsidence of the impurities. As they
become separated from the water they are carried by force of gravity to the bottom
of the standpipe, from whence they may be removed by means of a blow off cock.
Whenever convenient a deflector is placed in the stand pipe in front of the inlets
of the supply coils, and thus the water is obliged to descend to the mud drum
before ascending to the supply coils, thereby causing a more perfect subsidence
of the impurities and depuration of the water.
Another feature of the invention is its freedom from explosion: The water
level being high up at the stand pipe and much above the level of the
coils within the boiler shell, no danger will result in the lowering of this
water level from neglect or oversight of the engineer, as the coils will always
be full of water, and although the higher the water level the better the
circulation and the greater the efficiency of the generator, no actual danger
can accrue even if the water be below the top of the coils, as in such case
the water in the lower part of the coils will be evaporating, and the steam
from it will be cooling off the upper exposed parts of the coils, where it
will become superheated. This condition of things will not be dangerous but
simply uneconomical.
To attain these ends well known elements are employed which have hitherto
been arranged, employed and combined in various ways, and with other novel

page_text: features use is made of some of these elements and arrangements with relation to
each other as will more particularly appear hereinafter
Fig. 1 represents a vertical elevation partly in section of the generator.
Fig. 2 is a plan view partly in section on the line x x Fig 1.
Fig. 3 is a sectional elevation of a modification of the invention.
Similar letters of reference indicate corresponding parts.
A. represents generally the exterior enclosing shell of the generator. This shell
is made double as shown, the interior shell being marked F. An opening Z is
provided at the upper end of the generator through which air may, enter into the
hollow shell to pass downward and have its exit into the ash pit beneath the
grate. A suitable valve may be there provided to regulate the admission of air
through the hollow double shell. The air is drawn downward by the draft of the
boiler and enters beneath the fire box P of the generator. A certain amount of
air likewise enters through the holes or slots R, at the side of the fire box. The
air in its downward course becomes heated by contact with the inner shell Ę and
thus affords a hot blast to the fuel. Within the generator shell are several spiral
coils B which are arranged in conical form, one within another, and rest upon the
inclined supporting plate B¹ whose inner concave side is toward and within the
furnace and whose convexity is in the outer or ash-pit side. This supporting plate
B' being also designed to protect the lower turns of the pipe coils from the intense
heat of the furnace. The inner coil preferably should have a greater distance
between its contiguous turns than the outer ones thereof, giving a greater pitch
and insuring a quicker circulation. These series of coils communicate by pipes G.
with the outside horizontal mud drum or chamber E that together form in effect
an outside standpipe, and the extremities of said coils B communicate by pipes L
with the internal steam drum D Steam escapes from this latter drum through
the perforated tube N.
This steam drum D is strengthened longitudinally by a central brace Y. Below
this steam drum and crossing the coils is located the deflector or baffle plate X of
convex form lowest at the centre and rising laterally. M represents a water guage
communicating with the steam drum D.
The water should constantly be maintained above the level of the pipes L.
The steam drum is likewise provided with a drain pipe O.
K. Fig. 2 represents the feed pipe through which water can be forced into the
chamber or drun E. H represents a blow off pipe by which said mud drum E may.
be emptied. A fuel reservoir may be used in connection with the generator in
order that the fuel may be automatically fed to the furnace on the base burning
plan.
The operation of the apparatus may be readily understood.
A fire having been kindled in the fire box, the products of combustion pass
upward impinging against the inner coil pipes, and are thence deflected outward
through and between the other coils, escaping upward past the deflector or baffle
plate and thence escaping by the chimney S. The heat travelling vertically and
being deflected by the baffle plate, laterally at right angles to the heating surface,
the upper turns of the coils are impinged upon with greater intensity of heat than
the lower turns, thus the water is being gradually heated in its ascent in the coils,
favoring thereby circulation and making it impossible for the water to recede
back ward through the stand pipe to steam chamber.
с
The inner shell F will be heated somewhat by the products of combustion and
the air passing downward through the hollow shell will abstract heat therefrom
and enter the fire box in a hot condition, thereby ensuring a more perfect com-
bustion of the fuel. The water in the coils becoming heated ascends in different
ascending currents creating a rapid interior circulation. The water in the lower
part of the drum D descends through the pipes F, enters the chamber or drum E,
and thence returns to the bottom of the coils maintaining thus a constant
circulation. As a result it will be found that this generator will produce a large
amount of dry steam in proportion to the fuel consumed. In Fig. 3 is shown a

page_text: modification of the invention in which the operation is substantially similar. The
steam drum here is in effect the upper part of the stand pipe F, whose lower part
is in effect a mud drum; and when the boiler is in operation the hydrostatic
pressure of the water within the standpipe being greater than that within the
heating coils causes and maintains a constant circulation of water through the said
coils. The coils V V are also shown independent of the generating coils B, through
which coils V V the feed water may be introduced. A plate Z' is likewise shown
covering the junction of the return pipes.G, with the stand pipe so as to cause the
water to descend below the lower edge of said plate Z' before entering the pipes G.
By this means a more perfect deposit of sediment is obtained.
W represents a hand hole for the removal of such sediment.
The coils B shown in Fig. 3 increase in diameter from the bottom upward so
that as the water is gradually converted into steam in its upward movement, more
space is allowed thereby ensuring a more perfect circulation.
For marine purposes where the rocking motion of the vessel will diminish or
reverse the pitch of the coils, check valves are placed between the lower coil
connections and the stand pipe for the purpose of preventing the retrocession of
the water in the coils and the lifting thereby of the water in the standpipe
towards the steam drum, which may be caused by the intermittent motion of the
vessel.
Having now described this invention as communicated to me I wish it to be
understood that what is sought to be protected and claimed by Letters Patent is:-
1st The combination with a series of concentric spiral coils vertically arranged
with a steam drum located above them all within an enclosing shell, of an outside
stand pipe connected to said steam drum; each coil being connected independently
of the other at their tops with said drum, and with said stand-pipe below the level
of the coils within the shell, substantially as herein set forth and described.
2nd A series of steam forming coils located within the shell of a boiler, the
interior coil having a greater distance than the others between its contiguous turns
and also a deeper pitch, in combination with a drum located above the water coils
and connected with all of said coils below the water line, substantially as herein
set forth and described.
3rd In a steam generator or boiler, the combination within an enclosing shell, of
a series of vertically arranged coils, the area of the tubes or pipes of each of which
increases from below upward, substantially as herein shown and described.
4th In a steam generator or boiler of the character berein specified, the combi-
nation with the fire box of a hollow boiler shell containing air passages extending
about the same, substantially as herein shown and described.
5th In a steam generator or boiler, as a means for ensuring more perfect
combustion of the fuel and economising heat, a boiler shell containing air passages
opening at one end to the outer air, and at the other end into or below the fire box,
substantially as set forth.
6th In a steam generator or boiler the method substantially as set forth of
supplying heated air for the combustion of the fuel, consisting in causing air of
ordinary temperature to pass through the space between the inner and outer shell
of the boiler to become heated and thence downward into or beneath the fire box,
substantially as set forth.
7th In a steam generator or boiler constructed with spiral coils of pipes, a coil-
supporting plate, substantially as herein shown and described, said plate being also
designed for protecting the lower parts of the said coils from the intense heat of the
furnace, as set forth.
8th In a circulating coil steam generator, a series of independent coils set within
a shell and rising spirally and conically from a coil supporting and fire protecting
plate surrounding the grate, and covered above by a baffle plate of convex form
that is lowest at the centre and highest at its periphery, said coils being indepen-
dently connected to an outside stand pipe above and below, said stand pipe forming
a steam drum above the coil connections and the water line, and a mud drum below

page_text: the lower coil connections, the centre of which stand pipe forms a hydrostatic head
of water of greater specific gravity than that within the coils, by which a circulation
of water is established and maintained in the steam generator, as set forth
In witness whereof I the said William Phillips Thompson have hereunto
set my hand and seal this twenty-eighth day of March in the year of
our Lord one thousand eight hundred and eighty three.
XIZM D