Improvements in Mechanical Drying Apparatus.
Year: 1897

page_text: Date of Application, 9th June, 1897-Accepted, 17th July, 1897
COMPLETE SPECIFICATION.
Improvements in Mechanical Drying Apparatus.
I, HERBERT HEALEY WING, of 91 Wadsworth Street, Buffalo, County of Erie,
State of New York, 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 improvements in mechanical drying apparatus, all of
which will be fully and clearly hereinafter described and claimed, reference being
had to the accompanying drawings, in which :-
Fig. 1, represents a detached face view of the outlet damper.
Fig. 2, represents a vertical longitudinal section through a rotary drying shell
and its enclosing brick work.
One of the objects of my invention is to provide a means for securing a uniform
temperature around the drying shell of a rotary dryer or heating apparatus and to
increase the efficiency of the same. When the products of the combustion of fuel
are passed into the chamber in which the drying shell containing the material to
be dried, revolves, there is great liability that at some places the temperature may
rise high enough to ignite the material as it passes through the rotary shell or as
it drops from the end to the trough by which it passes out of the dryer chamber.
In order to obviate this serious difficulty, various means have been devised among
which may be mentioned the use of perforated fire brick arches, also the introduc-
tion of cold air, by which the temperature of the drying gases is reduced. In
both of these methods there is loss of heat and at the same time an imperfect result
obtained.
I have found the following method is a great improvement over what has been
done before as the temperature around the rotary shell can be maintained without
a variation of more than 10 degrees in a day's run, a very excellent result, and also
that the loss of heat is very small. The method consists in placing just below or
around the rotary shell a diaphragm of perforated iron plates so that the heated
gases before they can come into contact with the material being dried or the shell
containing the dried material, have to pass through a certain thickness of iron or
metal.
The action of this perforated metal diaphragm is to impart to the gases passing
through it a uniform temperature.
As the hottest gases pass through, the diaphragm being a good conductor of
heat absorbs the excessive heat and consequently the gases when they emerge on
the inner side are not so hot as they are on the outer. Then when gases of a
lower temperature pass through the diaphragm they absorb the excess of heat
which the hottest gases gave up and the result is that when they emerge on the
inner side of the diaphragm they have become heated and are about the same
temperature as the gases which were too hot before they passed through the
diaphragm.
The diaphragm thus becomes a reservoir or regulator of the temperature of the
gases passing through it. By becoming a reservoir it radiates heat uniformly
into the space surrounding the rotary shell, and is therefore more advantgeous

page_text: than the fire brick-arches having holes the size of the bricks for the distribution
of the hot gases into the chamber above in which the drying cylinder revolves,
which reflect the heat down, whereby valuable heat is lost.
The action of the metal perforated diaphragm is also superior in another way
to the fire brick arch having holes in it or the distribution of the hot gases in
that the hottest gases are reduced in temperature as they emerge on the inner side
and the cold gases hotter while with the fire brick arch the hottest gases are not
reduced in temperature when they emerge on the inner side as the fire brick being
a non-conductor of heat in contrast to a metal, the heat accumulates at these open-
ings and instead of modifying the heat of the gases, the holes in the fire brick arch
simply distribute the hot gases.
Referring to the drawings in detail, represents the rotary shell; 2, the per-
forated metal diaphragm. (The diaphragm can be located at any other place than
shown on this drawing without departing from this invention as a circular
diaphragm could be placed around the rotating shell, but the drawing as shown
illustrates its simple form); 3, is the surface chamber in which the fuel is com-
sumed; 4, the stack through which the drying gases pass into the air containing the
vapor of water absorbed from the material being dried. A damper is placed
across the discharge end of the shell 1, which can be opened or closed. It consists
of three plates, 5, 5 and 5b, each made substantially in the form shown in Fig. J,
or nearly so. They are mounted on the hub, 10", of the spider 10, so they can be
easily turned thereon, either to entirely open, or close, or partly close the opening
as indicated by the dotted lines 5°, in Fig. 1.
This damper allows the regulation of the temperature of the discharged material
as by closing it the area of the discharge end of the cylinder is reduced and as a
suction fan shown by dotted lines 6, is located in the stack 4, which continually
draws a constant volume of the drying gases through the shell 1, it follows that
when the damper 5-5 and 5b is closed, that in order for the suction fan to con-
tinually draw a certain volume of the drying gases, a larger volume has to pass
through the inlets between the sections and less through the discharge end of the
shell. When a smaller volume of the hot gases pass through the discharge end
the material as it is discharged is not heated to so high a temperature as when a
larger volume of the hot gases pass into the shell at this place. By adjusting the
opening of the discharge end a great variation of the temperature of the discharged
material can be obtained, an object which is very desirable.
6ª, represents a ball attached to the inside of the shell 1, by a chain. As the
shell 1, rotates, this ball catches on to the longitudinal ledges or shelves 7, and is
lifted up to near the top of the shell, when it drops giving the shell just sufficient
jar to loosen any material which is inclined to stick or bake to the shell, when it
is at the top and is easiest to loosen.
89, represents adjustable bearings at the discharge end of the rotary dryer. By
making the spider 10 as shown, and by employing the universal joints, it is possible
to change the pitch of the dryer by raising or lowering the discharge end without
producing any binding. As is shown in the drawing a very great variation in
the pitch is possible.
.
This is a very desirable feature, as, by changing the pitch, the length of time
during which the material remains in the dryer can be regulated, the greater the
pitch the quicker the material will pass through and vice versa, the less the pitch
the longer the material will be in passing through. By, this construction a great
variation in the drying effect can be produced so that a single dryer can bo
adapted to work on very different materials by simply making these adjustments.
12, represents an ordinary conveyor which conveys the material as it is
discharged from the shell, to the outside of the dryer.
The shell 1, is of the following construction:-
A number of conical, or if preferred evlindrical, sections are secured together in
such manner that, beginning at the feed end, each section enters within the
succeeding one to a distance of several inches, leaving an annular space between

page_text: the two sections, which may be about two inches more or less in radial width.
The sections of the shell, which may be of any desired number, may be polygonal
in shape but are preferably circular, and are secured together by any suitable
means, as by external supporting bars 1", placed at intervals around the cylinder
as shown in Fig. 1, thus forming an exceedingly rigid cylinder, provided with
ample inlet openings between the several sections, which, however, offer no
obstruction to the downward passage through the cylinder of the material being
dried. The bars 1", may be straight and extend between the sections where they
lap, as shown in Fig. 2, but they are preferably Z-shaped and extend outside of
both sections, as seen in said Fig. 2.
In order to support and rotate the shell, I prefer to use the construction shown
in Fig. 2, which consists in using universal joints, 11. By this construction I
obtain a flexible connection between the supporting shafts, 13 and 14, and the
rotary shell, 1, so that there is no liability of any binding occurring in case the
two supporting shafts, 13 and 14, are not kept in line, as by this construction
the shell will rotate as easily with the two supporting shafts out of line as if they
were in line.
To allow for the expansion and contraction of the rotary shell, I provide an
arrangement shown in Fig. 2, which consists in having the upper shaft, 14, slide
in a collar, 16, forming a part of the ball of the universal joint. The pin, 15,
which extends through the collar, 16 and shaft, 14, transmits the power from the
said shaft to the said collar and from thence to the spider, 10°, which is rigidly
secured to the rotary shell.
The sleeve, 17, prevents any material getting into the space which represents
the limit of the expansion of the rotary shell.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what I
claim is:
1. In a drying apparatus the shell made in sections one discharging into the
other and having inlets for the drying gases between the sections, substantially
as described.
2. In a drying apparatus the shell made in sections one partially inserted into
the other and secured together with an annular space between.
3. In a drying apparatus, the combination with a rotatable drying cylinder,
of a jarring device attached to the interior of said cylinder and operated by the
rotation of the same.
4. In a rotary drying apparatus, the combination with the drying shell having
internal longitudinal ribs, of a ball or weight attached to the interior of the shell
by a chain or equivalent.
5. In a drying apparatus, the combination with the drying shell having inlets
through its sides of a damper arranged across the discharge end and adapted to
nearly close the end of the cylinder.
6. In a drying apparatus, the combination with the shell made in sections one
partially inserted into the other and having inlets between the sections, of al
damper arranged across the discharge end of the cylinder and adapted to
substantially close the same.
7. In a drying apparatus, the combination with the shell made in sections one
partially inserted into the other and having inlets between the sections, of the
spiders supporting the shell and the damrer externally attached to the spider
which carries the discharge end of the cylinder and adapted to nearly close the
end of the cylinder.
8. In a drying apparatus, the combination of a rotary drying shell having each
end supported on an independent shaft, universal joints connecting the same with
the drying shell and means for permitting the expansion and contraction of said
shell.

page_text: 9. In a drying apparatus, a rotary drying shell connected to its supporting and
operating shafting by expansible universal joints.
10. The combination of a heating or drying shell of a regenerative perforated
metal diaphragm located between said shell and the source of heat.
11. In drying or calcining apparatus, the combination with the supporting
shafts of the rotary shell, of adjustable bearings whereby the pitch of the shell
can be regulated.
Deted the 27th day of Now 1007