Improvements in or relating to Drying and Pulverizing Apparatus.
Year: 1898

page_text: Date of Application, 3rd May, 1898-Accepted, 23rd July, 1898
COMPLETE SPECIFICATION.
Improvements in or relating to Drying and Pulverizing Apparatus.
A communication from THE NITROGEN PROCESSING COMPANY, of New Jersey,
United States of America, a Corporation organized under the laws of the
State of New Jersey, United States of America.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention consists in an apparatus for pulverizing and drying fertilizers
and other materials. The material to be operated on is carried through the
apparatus in an unbroken stream, being subjected at all times to heat and to the
action of screws and beaters which pulverize and feed it along toward the outlet.
During the latter part of the process the material is subjected to rotary beaters
and at the same time to currents of heated air which pass through the material
while it is violently agitated, thus subjecting each particle to the action of the
air and thoroughly drying it. In the accompanying drawings,
Fig. 1 is a plan view of the apparatus.
Fig. 2 is a side elevation, partly in section on the line 2-2 of Fig. 1.
Fig. 3 is a section on the line 3-3 of Fig. 1.
Figs. 4 and 5 are detail views of the beaters.
Figs. 6 and 7 are side and end views of a modified form of feeding and pulveriz-
ing device.
Figs. 8 and 9 are details of the screws
and 14, and
Fig. 10 is a sectional view of a modified air heating device.
In the drawings, 1 indicates the outer casing of the drier which, as shown, is
rectangular in plan and provided with a semi-circular trough or bottom 2. The
material to be operated on enters a hopper 3 and is fed through a revolving
cylinder by means of a screw 5. The cylinder rests on roller bearings 6 and
is turned by a gear 7. The screw is turned, preferably in a direction opposite to
that of the cylinder, by means of a chain or belt 8. From the cylinder 4 the
material is delivered to a chute 9 and thence to a second cylinder 10 which is
rotated by means of a gear 11, the gears 7 and 11 being driven by a pinion 12
upon a main shaft 13. The material is fed through the cylinder 10 by a screw 14
rotated by means of a chain or belt 15, the belts 8 and 15 being driven from the
main shaft 13. The screws may if desired, be driven by simple contact with the
cylinders instead of being positively driven, but by positively driving the screws
the material is less likely to accumulate and choke in the cylinders. Any number.
of cylinders and screws may be used.
From the cylinder 10 the material is delivered through a chute 16 to the bottom
of the casing and it is conveyed along the bottom of the casing to a delivery
hute 17 by means of beaters which are fast upon a shaft 18 which is driven from
·

page_text: the main shaft 13 by a belt 19. The beaters are shown in detail in Figs. 2 to 5
inclusive. They consist each of two parts, a part 20 rigidly attached to the
shaft 18 and a blade 21 pivotally connected to the part 20, the face of the blade 21
being slightly inclined in order to feed the material lengthwise of the shaft. The
pivoted blades 21 are connected to the rigid parts 20 by pivots 22 which, as shown,
are rods strung through the series of beaters included between the shaft bearings.
Instead of the rods the beaters may be provided with individual pivots if desired.
As shown, each part 20 has a hub 23 in which is an octagonal opening 24, the part
of the shaft 18 within the casing being of the same section and fitting the openings
closely.
The machine thus far described may be used without a heating apparatus for
pulverizing material, or the cylinders and screws may be used for this purpose
independently of the beaters. To effect the drying of the material simultaneously
with the pulverizing action hot air or gases are forced into the casing through a
series of pipes 25. The partition 26 which extends from the top of the casing
down nearly to the beaters directs the hot air around the cylinders 4 and 10 and
thence down through the compartment 27 to one side of the beaters. The rotation
of the beaters carries the air around the bottom of the casing under the shaft 18
and up into the compartment 28 upon the opposite side of the partition 26. To
render this circulation of the air more effective the partition 26 may be provided
with an extension 29 to cause the air to be discharged from the chamber 27 in
a direction tangential to the movement of the beaters.
The air may be heated in any suitable manner. It is preferred to use a
furnace 30 and to direct the products of combustion through the pipes 25 by a
forced draft. As shown, the air is driven into the furnace by a blower 31 through
a pipe having a branch 32 which discharges under the grate 36 of the furnace and
a branch 33 which discharges above the grate. By manipulating dampers 34, 35
in these pipes the temperature of the air and gases which are delivered to the
drier may be regulated. When hot gases are required the damper 35 is closed
and the air is driven through the grate by means of the pipe 32. When cooler
gases are desired pipe 32 is cut off and the air is driven through the pipe 33.
The dampers 34, 35, may both be open at the same time and by regulating them
the heat of the gases delivered to the drier can be very easily controlled. Further-
more, control of the gases is additionally effected by means of a valve 39 in a
pipe 38 leading to a suitable chimney. By stopping the blower and opening
the valve 39 the supply of the heat to the drier can be completely cut off. In
some instances the blower can be dispensed with and the necessary heat for the
drier derived from natural draft.
The operation is as follows: The material is delivered into the hopper 3 con-
tinuously while the machinery is in operation. The screws 5 and 14 rest on the
bottoms of the cylinders 4 and 10 and act as knives to cut and crush the material
against the cylinders. If the cylinders were stationary the crushing operation
would not be so effective and, furthermore, the cylinders would rapidly become
worn at the point of bearing of the screws. By rotating the cylinders the wear is
distributed throughout their circumference and their life is very much prolonged.
The cylinders and screws may be operated in the same direction but it is preferable
to operate them in opposite directions. The material is delivered from the
cylinder 10 into the bottom of the casing, which bottom, as shown in Fig. 3, is
semicircular and provided with a roughened or serrated interior surface.
material is struck violently by the beaters 21 and rapidly pulverized.
pivoted blades 21 are free to swing backward in case an obstruction is in the way,
such as a hard stone or other hard body, and breakage of the blades is thus pre-
vented. The current of hot air which comes from the chamber 27 passes along
with the heaters through the material in the trough 2. The beaters pulverize the
material and toss the particles into the chamber 28 and in this manner each 5
particle is subjected many times to the action of the hot air which passes up
through the chamber 28. The dried and pulverized material is finally discharged
The
The 5

page_text: through the chute 17 and the air from the chamber 28 ladened with moisture is
discharged through the opening. or chimney 37 at the end of the chamber 8.
In Figs. 6 and 7 is shown a grinding and feeding device which may be sub-
stituted for the screws 5 and 14. This device comprises a revolving cylinder 4 and
a screw consisting of sections 40, each section being provided with inclined teeth
and grooves 41. These screw sections are in the form of heavy disks having large
circular openings 42 through which loosely passes a rod 43. The disks rest on the
bottom of the cylinder 4 and are driven by it. The rod 43 simply serves to keep
them in place and approximately in line but it is small enough to permit
individual sections to rise and pass over obstructions. In operation these
disks 40 pulverize the material and feed it along substantially in the same manner
as do the screws 5 and 14. The disks 40 roll within the cylinders and are driven
by them, the rods 43 being stationary.
The screws 5 and 14 are preferably cast in sections, each containing a half turn
of the screw blade, as shown in Figs. 8 and 9. The hubs of these sections have
The screws
polygonal openings which fit over a shaft of similar cross section.
manufactured in this manner are very cheap and durable and are easily repaired.
Other methods of heating the air for the drier may be employed and other forms
of conveyors may be used, although those shown in the drawings are preferred.
In Fig. 10 the air is heated by being passed over a series of steam coils 44 and the
material is fed through the trough 2 by means of inclined blades 45 rigidly fixed
on shaft 46.
One of the principal features of this invention is the arrangement of the parti-
tion 26 which directs the heated air and compels it to rotate along with the
beaters 21, thereby bringing the air into intimate relation with the material to
be operated on. This arrangement may be utilized in all forms of driers and also
in evaporators for evaporating liquids of various kinds.
Having now particularly described and ascertained the nature of this said
invention, as communicated to me by my foreign correspondents, and in what
manner the same is to be performed, I declare that what I claim is:-
1. In a drier, the combination with the elongated casing, of a trough in the
lower part of the casing, a shaft having paddles operating in the trough, a vertical
longitudinal partition in the upper part of the casing having its lower edge adjacent
to the paddles, means for forcing air down upon one side of said partition and an
outlet for the moistened gases from the compartment on the opposite side of the
partition, substantially as described.
2. In a drying apparatus, the combination of a casing having a trough, the con-
veyor shaft adapted to move materials along said trough, a central longitudinal
partition above said conveyor shaft, a furnace, means for producing a forced draft
for said furnace and directing the hot gases down upon one side of said partition,
and an outlet to the chamber on the other side of the partition whereby said hot
gases may be circulated with the material through the trough, substantially as
described.
3. In a drying and pulverizing apparatus, the combination with a casing, a
shaft within the casing having pulverizing and conveying arms, means for direct-
ing heated gases around the shaft whereby said gases are intimately mingled with
the material operated on, a furnace for supplying the gases, and means for intro-
ducing a forced current of air into the furnace either above or below the grate
thereof, substantially as described.
4. In a grinding or pulverizing machine, the combination with a cylinder and
means for rotating the same, of a feeding and pulverizing screw extending through
the cylinder and resting on the bottom thereof, and means for turning the screw,
substantially as described.
5. In a grinding and pulverizing apparatus, a cylinder, and means for revolv-
ing the same, in combination with a feeding and pulverizing screw consisting of

page_text: a series of sections having inclined blades and a rod or shaft passing through
openings in said sections, the said screw normally resting on the bottom of the
cylinder, substantially as described.
BOULT & WADE,
Agents for the Applicant.