A Process of Transmitting Heat for Industrial Purposes.
Year: 1898

page_text: A Process of Transmitting Heat for Industrial Purposes.
I, GEORGE FREDERICK DINSMORE, of 7, Water Street, Boston, Commonwealth of
Massachusetts, United States of America, Chemist, 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 the art of transmitting heat, and more particularly to
the art of fusing or incandescing refractory or other substances. It utilizes in a
novel way the principle of the conservation of energy for taking up, transmitting,
and reproducing heat energy for industrial purposes.
Heretofore attempts have been made to transmit heat through the medium of
some fluid, such as steam, by increasing the sensible heat of such fluid to the
highest attainable temperature, and then carrying over the heat energy in the form
of sensible heat. This method, however, is unavailable where it is desired to secure
a very intense heat in the terminal retort, for if the superheating vessel or conduit
be made of fire clay, it cannot withstand the great pressure which the fluid at such
temperature must exert. If an iron conduit be used, it will become soft or melt
before such an intense temperature is reached, since, owing to the low conductivity
gases, a thin film in direct contact with the iron may become very hot, while the
body of the gas is much cooler.
of
In commercial practice raising the contents of a jacketed steam kettle to 200° C.
by this method of heat transmission is considered the best result attainable.
By the above method of heat transmission, it has been found commercially
impracticable to heat the contents of a jacketed steam kettle much above 200° C.
This has led practical men to believe that the raising of steam to an intensely high
temperature, even far below the point of dissociation, or incandescence, and then
carrying it to another place for producing a similar temperature, is commercially
impracticable and probably it is so.
My solution of this problem proceeds upon wholly different lines, my invention
consisting in applying the heat of combustion to a moving fluid body, for example,
steam, under such conditions that the greatest possible amount of heat energy is
converted into energy of motion, while a less amount is taken up as sensible
heat.

page_text: When heat is applied to a body of gas inclosed in a vessel or conduit having an
outlet, part of the heat so applied will appear as sensible heat and part as the latent
heat of expansion of the gas, or, as it may be otherwise expressed, the kinetic energy
of the gas in motion as it escapes through the outlet.
The proportions of the parts so appearing as sensible heat and as kinetic energy,
respectively, will vary according to the facility afforded for the escape of the gas.
If the escape of the gas be impeded or its flow retarded, then the part of the heat
energy applied, appearing as sensible heat, will be increased, while the part appearing
as kinetic energy or energy of expansion will be diminished. If, on the other hand,
the conduit is so constructed that a free unobstructed flow of gas is permitted, a less
portion of the heat energy applied will be manifested as sensible heat and a greater
part as kinetic energy.
much
The capacity of a fluid to take up or absorb heat units from its conduit
greater when the fluid is in motion than when it is at rest, and it increases with the
rapidity of the motion.
If, now, the transmitting fluid be forced under pressure into one end of a long
conduit or pipe, and heat be applied along the length of the pipe, the velocity at
which the fluid entered the pipe would be enormously increased by the continuous
expansion of the fluid stream in the highly heated conduit. If this rapidly moving
stream as it leaves the conduit be impinged against some obstruction arranged in its
path much of the energy of motion will, by the sudden arrest of said movement, be
recovered as sensible heat.
To illustrate, I may state that when I had my heating coil discharging through
an outlet pipe directly into the open air I held a piece of 2 x 4 scantling in the path
of the escaping steam, and found that the part of the scantling impinged upon was
quickly raised to incandescence so that it glowed like a live coal.
In order to recover the greatest possible amount of sensible heat, the moving fluid
stream should be impinged upon some obstruction in a vessel or retort constructed
to maintain the gas therein under pressure whereby the steam or gas entering is
compressed and made to yield up its sensible heat. The compression of the gas,
however, while desirable for some purposes may be dispensed with where a less
intense heat will suffice, as in welding, brazing, or in fusing the less refractory
metals, or in certain open hearth processes. Other applications of this process will
readily suggest themselves.
Before describing a form of apparatus suitable for use in connection with my
process, I will briefly state the conditions proper to be taken into account in the
practice of this process.
First. In order that the heat in the combustion chamber may be abstracted and
carried off in the form of kinetic energy, the conduit containing the steam to be
heated should be so constructed as to offer the least resistance to the flow of the steam
or gas, so as to permit the exceedingly rapid expansion of the column of steam. A
helical coil is, perhaps, the best conduit.
Second. In order that the steam may present the largest possible surface in
proportion to its volume, in direct contact with the heated conduit, the conduit
should be of comparatively small diameter, say for illustration in.
Third. Since rapidly running steam has a much higher capacity to take up
heat than steam at rest, the steam should be introduced into the heating coil
under considerable pressure in order to secure a rapid movement through the
coil.
Fourth. The length of coil should be as great as practicable in order that the
steam may be exposed to the action of the heat to the greatest possible extent.
If the coil is made too long, so much heat will be absorbed that the end of the coil
will melt off, so this matter to some extent will determine itself. Of course the
length of coil may vary with different boiler pressures and with different diameters
of coil.
Fifth. In order to recover the greatest possible quantity of sensible heat, the
pressure in the terminal vessel or retort should be as great as practicable.

page_text: Reference is now made to the accompanying drawings in which I have shown an
elevational view, partly in section, of one forin of apparatus suitable to be used in
the practice of my process.
It is obvious that changes may be made in the form and proportions of the
apparatus set forth, those given herein being merely illustrative and such as I have
employed in practice with most excellent results.
The apparatus shown comprises a steam or gas generator A, of any suitable type,
a superheating furnace B and a retort C.
The superheating furnace is lined with refractory material and is provided
with suitable adjuncts for feeding fuel and maintaining rapid combustion of the
fuel.
The coil which I have employed in practice was of in. internal diameter
and about 236 ft. long, the same being arranged in eighteen nearly square
turns or coils, the corners being rounded, the side of each coil being about
3 feet long.
The steam from the boiler at about 100 pounds pressure was admitted to the
coil 6 by means of the pipe d controlled by a suitable valve.
The outlet end of the coil b was connected with the retort C by means of
pipe f.
The retort C was lined with refractory material, such as fire-brick, and partly filled
with loosely arranged blocks of material to be fused, and was constructed to exclude
the outside air and to withstand considerable pressure. Its outlet or offtake pipe g
is, when the most intense heat is desired, provided with a suitable pressure device,
shown at h. Suitable draw off or clean outs may be employed according to the
particular use to which the apparatus is to be put.
With a coil such as I have described and with a superheater in which I have
employed coke under forced draught, I have maintained a mass of coal or coke in
the. retort continuously in an incandescent state for more than fifteen hours,
without the admission of air, and at the end of that time I have observed through
peep holes in the retort that the mass was hotter than at the start..
I have found that I can transmit the heat from the superheater to the retort
substantially as fast as it is generated. Indeed, when using an oil burner in the
superheater, the steam abstracted the heat so fast that the temperature in the
superheater was actually reduced below the point of ignition of the oil, so that
the flame was extinguished.
Obviously, for some purposes it might be better to use air or some other fluid
substance instead of steam and such a substitution would, of course, fall within the
scope of my invention.
The length of the heating coil is to some extent self-determining, since, if it be
too long, the end will melt. off. It is not necessary to attempt to set forth the length
of coil best adapted to meet variations in use, it being sufficient to state what may
be inferred from the foregoing explanation, that with a larger diameter of coil a
greater length may be used. The length of coil to be used may vary also with
different pressures of steam or gas and with the intensity of the fire in the
superheater.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what
I claim is
1. The process of fusing or incandescing refractory or other material, which
consists in applying heat to a rapidly moving fluid stream under such conditions
that the heat energy applied is mainly utilized in expanding said stream and
accelerating its velocity, then impinging said stream against refractory or other
material at such velocity and temperature that sufficient heat is evolved to fuse or
to incandesce the material.
2. The process of transmitting heat energy, which consists in applying heat to a
rapidly moving fluid stream under such conditions that the heat energy applied is

page_text: mainly transformed into kinetic energy, then arresting or obstructing said fluid
stream by impact or compression, so that the kinetic energy is mainly
transformned into sensible heat available for the fusing or incandescing of various
substances.
3. The process of fusing refractory or other material, which consists in passing a
fluid stream at high pressure through a superheater coil free from obstructions,
applying the heat of the superheater chiefly to expand said stream and greatly
accelerate its velocity, then impinging said stream against a mass of material in a
closed vessel constructed to maintain a high internal pressure, and-by said impact
and compression, fusing said material.
GEORGE FREDERICK DINSMORE.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.