Year: 1899

page_text: Date of Application, 30th Sept., 1899
Complete Specification Left, 2nd July, 1900-Accepted, 4th Aug., 1900
CHARLES THEODORE HENNIG, Chemist, Rosherville Hotel, Northfleet, Kent,
do hereby declare the nature of this invention to be as follows:-
Owing to the tendency of heated gases to rise and to pass rapidly through a
tube of limited length the heat introduced into rotary furnaces has been found
to be but poorly utilized. And, besides waste of heat, considerable power is
required to revolve such furnaces.
My objects are to effect a higher utilization of the heat employed in calcining,
roasting or drying materials and to reduce the expenditure of power in con-
nection with such processes; and to accomplish these ends. I construct a furnace
consisting of a series of connected—and preferably descending-elongated_cham-
Lers, each successive member of which forms an angle with the one preceding it.
The course through such a series of chambers being of greater length, and being
broken or changed in direction the heat and the materials passing through it are
kept in longer contact than they possibly can be in a single rotary furnace.
In cases where the passage of the materials treated can be assisted through
my series by a screw or other practicable means, I prefer to make the chambers
stationary and more or less flat or low in cross-section, so as to keep the heat
down near the load to be acted upon; but my invention is not limited in its
application to a series of chambers of a particular cross-section, nor to stationary
chambers for the series may include rotary, rocking or other movable chambers.
In practice the chambers may be made longer or shorter, the number in a
series may be two or more and their degrees of inclination may vary. The
essential characteristics of my furnace are that the course through it as a whole
shall be of considerable length, and tortuous, and that the chambers shall be
so far as possible low or broad rather than high or deep.
I prefer, in furnaces in which a high degree of heat is employed, to make
the lower or final chamber of my series vertical so that the materials treated
may fall through it to its point of discharge--the heat being introduced into said
final chamber above its point of discharge and rising upwards through it into
and through the chamber or chambers above it.
The chambers in any given series are suitably connected to prevent escape of
heat and to facilitate the passage of materials; and a given series may be
composed entirely of movable chambers or of stationary chambers or of a com-
bination of the two kinds.
A screw or other suitable means may be employed in stationary chambers,
where necessary to facilitate the passage of materials through them; and baffles
may be constructed inside the chambers to deflect or retard the passage of the
heat.
The uppermost chamber in a series is provided with a suitable opening for

page_text: the admission of materials and with an outlet for the escape of the heat and
the evaporations, and the lower chamber with openings, as stated for the dis-
charge of the materials and for the introduction of heat.
Dated 30th day of September 1899.
I, CHARLES THEODORE HENNIG, Metallurgist, formerly of Northfleet, England,
now of 71, Johnson Avenue, Brooklyn, New York, U.S.A., 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:-
Owing to the tendency of heated gases to rise and to pass rapidly through a
tube of limited length, the heat introduced into the rotary furnaces at present
used for calcining roasting and drying materials is but poorly utilized. And,
besides waste of heat, considerable power is required to revolve such furnaces.
My objects are to effect a higher utilization of the heat employed in calcining,
roasting and drying, and to reduce the expenditure of power in connection with
such, processes; and to accomplish these ends I construct a furnace consisting of
a series of connected-and preferably descending-elongated chambers, each
successive member of which forms an angle with the one preceding it. The
course through such a series of chambers being of greater length, and being
broken or changed in direction, the heat and the materials passing through it
are kept in longer contact than they possibly can be in a single rotary furnace.
In cases where the passage of the materials to be treated can be assisted through
my series by a screw or other practicable internal means, I prefer to make
the chambers stationary and more or less flat or low in cross-section, so as to keep.
the heat down near the load to be acted upon; but my invention is not limited
in its application to a series of chambers of a particular cross-section, nor to
stationary chambers, for a series may include rotary, rocking or other movable
chambers.
In practice the chambers may be made longer or shorter, the number in a series
may be two or more, and their degrees of inclination may vary.
I prefer, in furnaces in which a high degree of heat is employed, to make the
lower or final chamber of my series vertical, so that the materials treated may
fall through it to its point of discharge-the heat being introduced into said
final chamber above its point of discharge, and rising upwards through it into
and through the chamber or chambers above it.
The chambers in any given series are suitably connected to prevent escape of
heat and to facilitate the passage of materials.
A screw or other suitable conveying means may be employed in stationary
chambers to facilitate the passage of materials through them; and baffles may
be constructed inside the chambers to deflect or retard the passage of the heat.
My invention is illustrated by the constructions shown in the accompanying
drawings in which like parts are designated by like numbers and letters.
Figure I shows a continuous furnace composed of two descending stationary
chambers A and B and a final vertical chamber C. The two upper chambers are
made low in cross-section and are fitted with screws 3, 3 to assist the passage of
materials through them. These screws are supported by hangers or supports 6, 6
and are connected outside the chambers by a bevel-gear 5, and revolved by power
applied at pulley 4. Materials introduced at 1, after passing through the furnace,
are discharged at 2. Heated gases are introduced at 7 and, passing upwards carry-

page_text: ing the evaporations with them, find an outlet at 8. A door is provided at 9.
to admit of access to the chambers, if necessary. A baffle or deflector is shown
at 10. Cast-iron or other suitable plates may be inserted along the bottom of the
upper chambers to protect the lining from the wear of the screws and of the
materials.
It will be noticed that no conveying means whatsoever are required in the
final vertical chamber-the materials falling through it by gravity. I lay
particular stress upon the practical importance and value of this final-chamber
for it enables a result to be brought about which is very desirable in the calcina-
tion of various materials, namely, a brief and thorough exposure of the materials
to the gases when they are first introduced and at their highest temperature.
I prefer to make the walls of this final chamber slightly expanding from top
to bottom to prevent contact and adherance of the materials falling through it.
Figure II shows my furnace composed of a descending stationary chamber A,
a descending rotary chamber D) and a final vertical chamber C. This substitu-
tion of a rotary chamber in place of the stationary chamber shown in Figure I
is desirable where higher heats are employed, as a rotary chamber is revolved
by external application of power and no internal conveying means are required.
A rocking chamber may be used instead of the rotary chamber without departing
from my invention.
Figure III is a cross-section showing a preferred form of stationary chamber,
with screw 3 in position, and hanger 6, and protecting plate 11.
It will be understood that the furnace should be built of suitable fire-resisting
materials and that the screws or other conveying means within any
of the chambers should be made of metals capable of withstanding
the effects of the heat employed. For high heats I have found nickel alloys to
be the most suitable. The bearings within the chambers should be of graphite
or equivalent material.
In cases where the furnace is to be used simply for drying at a low temperature
the final vertical chamber shown in Figures I and II may be omitted from the
series.
My furnace may be composed of various chambers in different ways and I
wish it understood that the constructions shown are but examples.
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 ―
or
and
1. A calcining, roasting or drying furnace consisting of a series of two or
more connected stationary movable chambers, the said series being so con-
structed that each successive member of it forms an angle with the member
preceding it; the first or uppermost chamber being provided with suitable
openings for the admission of materials and the escape of heat and evaporations
and the last chamber with openings for the admission of heat and the discharge
of materials all substantially as described.
2. In a calcining, roasting or drying furnace, the combination of a low
stationary chamber (or chambers) provided with internal conveying means,
with a final vertical chamber, substantially as described and shown.
3. In a calcining, roasting or drying furnace, the combination of a low
stationary furnace chamber provided with internal conveying means, a rotary
chamber and a final vertical chamber, substantially as described and shown.
4. In combination in a calcining, roasting or drying furnace, a final vertical
chamber, substantially as shown and described.
Deted this 20th dov of Tun
1000