Preventing the Loss (by Radiation or otherwise) of Heat from the Sides of Steam Containing Vessels, and Superheating the Steam contained therein.
Year: 1895

page_text: Date of Application, 7th Oct.. 1895
Complete Specification Left, 7th July, 1896-Accepted, 28th Sept., 1896
PROVISIONAL SPECIFICATION.
Preventing the Loss (by Radiation or otherwise) of Heat from the
Sides of Steam Containing Vessels, and Superheating the Steam
contained therein.
I, BENJAMIN HOWARTHI THWAITE of 95 Finsbury Pavement London Civil
Engineer do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved means by which the jackets of steam
containers whether for producing motive power, or for other purposes, can be
maintained at a higher temperature than the highest temperature of the enclosed
steam, and without the necessity of establishing within such Jackets higher
pressures than 20 lbs. to the square inch. The limit of pressure rarely exceeding
3 lbs. to the square inch, it may indeed be less than this.
By my invention the troubles of condensed water associated with steam jackets
are avoided, and a far greater thermo-dynamic efficiency in steam engine practice
will be attainable.
Briefly described, my invention is as follows:-Instead of employing a gaseous
media, such as steam or hot air for jacketting purposes, I employ the forced or
naturally induced circulation of a special fluid, that can be heated up to a high
(if not higher) temperature than 400 degrees Fahr. without becoming volatilised,
and that will not preferably ficeze at the ordinary freezing point of water, or at
32 degrees Fahr.
The agent I prefer to employ is glycerine (commercial or refined). But I may
employ any mineral oil that does not volatilize below a temperaturo of
250 degrees Fahr., and which oil has had its volatile hydrocarbons removed by
graduated distillation. The other agents I employ are inercury and an alloy of
sodium and potassium,-I provide a complete cycle circulating arrangement of
pipes; at one loop of this cycle of circulation, I provide a heating coil or other
form of heating apparatus and at the other loop I provide a temperature controlling
or cooling or other form of heat absorption apparatus.
Intermedially between the two, 18 located the steam engine cylinder or other
form of steam container.
The circulation of the oil may be effected naturally-because the difference of
temperaturo between the two extreme loops, one heat absorbing and the other heat
giving, will induce circulation. But I generally profer to employ a force pump,
by which the oil is made to flow steadily, and in uniform quantities, and by which
the proper degree of circulation can be controlled.
In the application of my invention to a steam engine-I place the glycerine
heating coil in the chimney Alue or in the funnel, and in such a way that it becomes
nearly beated to the temperature of the chimney gases.
For the purpose of forming this heating coil and the cooling one, I prefer to
employ a round or flattened copper tube, I may arrange the tube in a grid-iron
fashion so that it shall offer as much surface as possible to the passing gases.
This heating coil may be hung with flexible connections so that it can be
agitated when it is desired to shake off any deposited carbon. The coating
of this carbon is not objected to, as long as it does not attain an excessive
thickness, because a carbon covering will tend to preserve the surface of the
tubing.

page_text: I connect one end of this heating frame tubing with the steam engine cylinder
Di steam container in such a way that the hot glycerine is compelled to traverse
(or flow over the entire or greater part of the steam cylinder or steam container.
From the outlet pipe on the steam cylinder, I lead the hot glycerine to the
temperature-controlling-or-cooling-coil or other apparatus, which consist of a
series of coils through which one or through the entire zet) the glycerine can be
compelled to flow as desired. These coils are submerged in water, which 18
maintained in circulation so as not to become overheated, or the water may be
refrigerated, and instead of the water I may employ any other refrigerating or
ocoling fluid.
This cooling apparatus enables the temperature of the glycerine to be exactly
controlled. Assuming the temperature of the glycerine is sufficiently low, its
flow can be bye passed without passing through any of the coils. If the
glycerine is too high in temperature, it can be passed though one coil of the
cooler, and if the temperature still rises it can be inected into a second or into a
thud cooling coil. The glycerine is duected into sufficient coils and the flow of
water through the cooler is regulated until the temperature of the glycerine
remains stationary.
The cooling coils are provided with a thermometer by which the temperature
can be readily tested, and if necessmy the extieme allowable temperature of the
oil can be automatically controlled.
From the cooling coil the glycerine is conveyed to a stand pipe having an upper
outlet open to the atmosphere and extending above the level of both the heating
and cooling coil. I may provide the open ended safety pipe with a safety valve,
Bo that should gas be evolved it can readily escape. I may provide a connection
between the safety pipe and a condenser to recover the glycerine or other volatilised.
fluid by condensation.
(A glycerine-glass-gauge enables the level of the glycerine to be readily
ascertained.) From this stand-pipe the glycerine is conveyed to the heating coil.
When natural circulation is desired, the respective elevations of the heating and
cooling coils are so arranged as to produce the best results.
I do not however confine myself to any specific arrangement of position, which
will depend upon the special circumstances associated with each application. For
steam containers working under pressure, I may not only enclose the heating space
with a jacket of glycerine, but I may also employ coils of small bore pipes placed
in the interior of such steam containers, and through these coils of pipes disposed
in such a way as to distribute the heat to the steam in the best possible manuer, I
circulate the hot glycerine and if necessary place the tubes in the enclosed water
as well, indeed my invention may be occasionally used to induce the circulation of
the water in such steam containers.
By this application I effectually super-heat steam and with absolute safety, and
in order to prevent the condensation of this super-heated steam in its flow between
the steam boiler and the engine, I may jacket the steam pipe and circulate
through such jacket a rapid flow of hot glycerine.
I may under certain circumstances ciculate the glycerine through a pipe placed
in the centre of such steam pipe by this means steam may be conveyed a
considerable distance without condensation intervening. When I wish to muciense
the limit of fluidity, under temperaturo influences, of the different agents employed,
1 subject them to a pressure, not exceeding say 45 lbs. to the square inch and in
this case, 1 fill the safety stand pipe with gaseous carbon dioxide to allow for the
expansion of the liquid employed.
Dated this Fifth day of October 1895.

page_text: Preventing the Loss (by Radiation or otherwise) of Heat from the
Sides of Steam Containing Vessels, and Superheating the Steam
contained therein.
1, BENJAMIN HOWARTH THWAITE of 29 Great George Street, Westminster
Civil Engineer, formerly of 95 Finsby Pavement London EC. 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 relates to an improved means by which the jackets of steam
containers, whether for producing motive power or for other purposes, can be
maintained at a higher temperature than the highest temperature of the enclosed
steam, and without the necessity of establishing within such jackets, higher
pressures than 20 lbs. to the square inch.
The limit of pressure rarely exceeding 3 lbs. to the square inch-it may indeed
be less than this.
By my invention, the troubles of condensed water associated with steain jackets
are avouled, and a far greater thermo-dynamic efficiency in steam engine practice
will be attainable.
Befly described my invention is as follows Instead of employing a gaseous
medin such as steam or hot air for Jacketting purposes, I employ the forced or
naturally induced circulation of a special fluid, that cau bo heated up to a high if
not a higher temperature than 400° Fahrenheit without becoming volatilised, and
that will not preferably freeze at the ordinary freezing point of water, or
at 32° Fahrenheit, or 1 degree Centigrade.
The agent I prefer to employ is glycerine, commercial or refined.
But I may employ any mineial oil that docs not volatilize below a temperature
of 250° Fahrenheit and which oil has had its volatile hydrocarbons removed. Tho
other agents I employ are mercury and an alloy of sodium and potassium.
I provide a completo circulation arrangement of pipes-at one loop of this cycle
of circulation I provide a heating coil or other form of heating apparatus and at
the other loop, I provide a temperature controlling or cooling or other form of heat
absorption apparatus.
1 may intermediately between the two locate the steam engine cylinder or other
form of steam container.
The circulation of the oil may be effected naturally because the difference of
temperature between the two extreme loops-one heat-absorbing the other heat-
giving will induce circulation. But 1 generally prefer to employ a force pump,
by which the oil 18 mado to flow steadily and in uniform quantities and by which
the proper degree of circulation can be controlled.
In the application of my invention to a steam engine I place the glycerine
heating coil in the chimney flue or in the funnel, and in such a way that it becomes
nearly heated to the temperature of the chimney gases.
Foi the purpose of forming this heating coil and the cooling one, I prefer to
employ a round or flattened copper tube. 1 may arrange the tube in a grid-ıron
fashion so that it shall offer as much surface as possible to the passing gases.
This henting coil may be hung with flexible connections so that it can be
agitated when it is desired to shake off any deposited carbon.
The coating of this carbon is not objected to as long as it does not attain an
excessivo thickness because a carbon coveting will tend to preserve the sai face of
the tubing.
I connect one end of this heating frame tubing with the steam engine oylinder

page_text: or steam container in such a way that the flow of hot glycerine is compelled to
traverse or flow over the entire or greater part of the jacket of the steam cylinder
or steam container. From the outlet pipe m the steam cylinder, I lead the hot
glycerine to the temperature controlling or cooling coil or other apparatus which
consists of a series of coils through one or through the eutue set, tho glycerine
can be compelled to flow as desired. These coils are submerged in water which 18
maintained in circulation so as not to become over heated, or the water may be
refrigerated and instead of water I may employ any other refrigerating or cooling
fund. This cooling apparatus enables the temperature of the glycerine to be
exactly controlled.
Assuming the temperature of the glycerine is sufficiently low, its flow can be
bye passed without passing through any of the coils. If the glycerine is too high
in temperature, it can be duected through one coil of the cooler, and if the
temperature still rises it can be dnected into a second or into a third cooling coil,
the glycerine is dnected into sufficient coils and the flow of water through the
cooler is regulated until the temperature of the glycetime remains stationary The
cooling coils are provided with a thermometer by which the temperature can be
readily tested, and if necessary the extreme allowable temperature of the glycerine
or oil can be automatically controlled.
From the cooling coil, the glycerine is conveyed to a stand pipe, having an
upper outlet open to the atmosphere and extending above the level of the heating
coil. I may provide the open ended pipe with a safety valve so that should gas be
evolved it can readily escape.
A glycerine glass gauge enables the level of the glycerine to bo readily
ascertained. From this stand pipe the glycerine is conveyed to the heating coil.
When untural cuculation 18 desned, the respectivo elevations of the heating and
cooling coils are so arranged as to produce the best results.
For steam containers working under pressme, I may not only enclose the
heating space, with a jacket of glycerine, but I may also employ coils of small
bolo pipes placed in the interior of such steam containers and through these coils
of pipes disposed in such a way as to distribute the heat to the steam in the best
possible manuer and, if necessary, to the enclosed water as well, I circulate the
heated fluid glycerine, indeed my invention may be occasionally used to induce
the circulation of the water in such steam container
By this application I effectually superheat steam, with absolute safety and in
order to prevent the condensation of this superheated steam in its flow between the
steam boiler and the engine, I may jacket the steam pipe and cuculate through
such jacket a rapid flow of hot glycerine.
I may, under certain circumstances, circulate the glycerine through a pipe placed
in the centre of such steam pipe, by this means steam may be conveyed a
considerable distance without condensation intervening.
It will be obvious that the manner of application of my invention will greatly
depend upon the disposition of the parts constituting the steam power or steam
storage plant probably no two arrangements will be exactly identical, I therefore
submit the design shewn on Figure 1, merely as an example of one application
of my invention in this instance to a land steam engine of the ordinary stationary
class with its associated Cornish or Lancashue boiler.
I will indicate the various clements constituting my invention by means of
capital letters.
A, represents the Lancashire or Cornish boiler, B, the boiler flue collecting the
waste gases as they issue from the tubes or flues of such steam generator and
introducing them to the chimney flue, C, in which I contrive to instal the glycerine
beater coil, D, it will be seen to consist of a framework of tubes of a grid-iron
form, which, whilst not interfering with the chimney draft effect on the boiler fire
grate, nevertheless provides a very considerable heating surface exposure to the
passing gases. This heating framework of tubes may be of copper or of any other
suitable metal.

page_text: The glycerine is introduced to the heating framework, D, by means of the inlet
pipe, E, which forms, with the outlet pipe, F, and as will be seen, a complete cycle
of pipes. The glycerine is forced to flow through the entire length of the pipes
constituting the cycle of circulation, either naturally- -as described but preferably,
by a centrifugal or other simple kind of pump, G. I prefer to place the pump in
the line of pipes leading to, rather than from, the heating coil, but as long as tho
pump is placed in the line of pipes, the system will work with more or less
complete satisfaction. The pipe, F, leads the glycerine to the jacket, II, of the '
cylinder, 1, of the steam engine, J, after passing around the cylinder, the glycerine
flows directly back to the heating coil framework, D.
It may, however, be bye-passed into a coil framework of pipes, K, placed in the
water vessel, L. By this means the temperature of the glycerine or other fluid
used may be reduced as desired.
In order to re-condense any of the vapour or gases that may be evolved from the
glycerine or other fluid specified as usable for the transmission of the heat, and
which may be produced by the accidental over-heating of the enculating fluid,
I place a secondary coil, M, in the water vessel, L.
To permit of the leady escape of such an accidental evolution of vapour or gas
from the over-heated fluid, I provide a vertical stand safety pipe, O, this not only
allows for the escape of the evolved gases, but also for the expansion of the
circulating fluid employed
On this stand pipe, which serves for the feed supply pipe, I fix a glycerine, (or
other heating fluid) level gauge, P, and in such a position that the attendant can
be satisfied that the circulating fluid exists in adequate quantity.
I also provide, and in positions easily seen, a thermometer Q that will register
temperatures up to 700° Fah. and the bulb of which is permanently exposed to the
glycerine, and preferably at the maximum temperature, in which it exists in the
line of circulating pipes. I provide the stand safety pipe with a seal arrangement R,
so that if the vapours and gases are evolved, they are compelled to force the
seal R before they can escape to the outer air by the funnel, S. I connect the
stand pipe below the seal by pipes, T, to the condenser coil. M, this permits
the flow of the evolved gases or vapour through the condenser, and exposes them
to the refrigerating influence the vapours or gases are re-condensed to Huid which
1s available for re-use.
It will be readily recognised that the system is applicable to almost every
conceivable kind of land and marine steam engine practice, and that the application
requires no particular skill.
When it is convenient, the cooling apparatus can be so fixed as to compel
natural circulation, to come into play, obviating the employment of the circulating
pump.
It will be obvious to the reader, that when it is desired to employ the invention
for applying heat to enclosed steam or water, such as a steam boiler, the only
modification required from that shewn in diagrammatic figure is that the circulating
fluid is led through pipe coils placed inside such stean oi water, in a manner such
as to obtain the best distibution of heat.
Having now particularly descubed and ascertained the nature of my said inven
tion, and in what manner the same may be performed, I declare that what I
claim is:-
First. The method of forcible circulation of a fluid such as is glycerine, capablo
of being heated up to a high temperature above 212° Fah., without volatilisation,
for preventing the loss of heat from steam containing vessels whether such
contained steam, is continuously contained as m a steam pipe, or intermittently
contained as in the cylinder of a steam engine substantially as described.
Second. The method of applying forcibly circulated and highly heated fluid, for
the purpose of heating or super-heating, by coils placed directly in the steam or
water required to be heated or super-heated.

page_text: Third. The arrangement described for controlling the temperature of the
circulating fluid.
Fourth. The safety stand pipe arrangement substantially as shewn and
described.
Fifth. The arrangement adopted for securing the maintenance of an adequate
supply of the heating circulating fluid.
Sixth. The method shewn and described for re-condensing the vapours or gas
evolved from the heated circulating fluid, in combination with the other clements
constituting my invention.
Seventh. The methods adopted for promoting and securing the continuous
circulation, of the hot fluid by means of a force pump of the centrifugal or other
type, or by the establishment of natural circulation, substantially as shewn and for
the purpose described.
Eighth. The method described of suspending the heating col framework, by
means of flexible connections so that the adhering smoke or carbon can be
shaken off.
Ninth. The method of super-heating steam, flowing through steam pipes by
placing in such pipes, coils of tubes, through which I continuously establish a
constant circulation of highly heated Hund.
Dated thin 4th dow of Lule 1806
B. II. THWAITE.