U.S. patent number 3,751,267 [Application Number 05/173,066] was granted by the patent office on 1973-08-07 for material treating method.
This patent grant is currently assigned to Range Engineering Development Corporation. Invention is credited to Norman H. Sachnik.
United States Patent |
3,751,267 |
Sachnik |
August 7, 1973 |
MATERIAL TREATING METHOD
Abstract
This patent discloses a method for treating material such as
grain, manure, alfalfa, lightweight aggregate, etc. Hot air
circulates throughout the entire system. Heat is first added where
desired to the product in a preheater. Additional heat is then
added in a heater section where the material is further heated and
material such as grain may be popped if desired. The grain may then
be passed through conventional rollers.
Inventors: |
Sachnik; Norman H. (Houston,
TX) |
Assignee: |
Range Engineering Development
Corporation (Ft. McKavett, TX)
|
Family
ID: |
22630390 |
Appl.
No.: |
05/173,066 |
Filed: |
August 19, 1971 |
Current U.S.
Class: |
426/520;
252/378P; 34/363; 432/13 |
Current CPC
Class: |
A23L
7/183 (20160801); A23N 12/08 (20130101); F26B
17/10 (20130101); F26B 23/02 (20130101); F26B
21/04 (20130101) |
Current International
Class: |
A23L
1/18 (20060101); A23N 12/08 (20060101); A23N
12/00 (20060101); F26B 21/04 (20060101); F26B
17/00 (20060101); F26B 17/10 (20060101); F26B
21/02 (20060101); F26B 23/00 (20060101); F26B
23/02 (20060101); F27b 015/00 () |
Field of
Search: |
;34/10 ;263/21A,21B,52
;252/378,378D |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Camby; John J.
Claims
What is claimed is:
1. The method of popping grain, comprising
moving grain along a selected path while adding heat thereto until
said grain pops,
separating at least a portion of the popped grain from the
remainder of the grain and accelerating its movement relative to
the remainder of the grain and returning it to said path at
selected downstream points therealong to thereby reduce retention
time of early popping grain on said path.
2. The method of popping grain, comprising
moving grain along a selected path while adding heat thereto until
said grain pops while continuously agitating said grain,
separating at least a portion of the popped grain from the
remainder of the grain and accelerating its movement relative to
the remainder of the grain and returning it to said path at
selected downstream points therealong to thereby reduce retention
time of early popping grain on said path.
3. The method of popping grain, comprising
moving grain along a selected path while adding heat thereto until
said grain pops,
said path having a plurality of upwardly and downwardly directed
sections,
movement of said grain along said upwardly directed sections of
said path provided by entraining said grain in an upwardly moving
stream of air,
separating at least a portion of the popped grain from unpopped
grain at the upper end of upwardly directed sections of said path,
and
accelerating movement of said portion of popped grain relative to
the remainder of the grain to the next upwardly directed
section.
4. The method of claim 3, wherein at least a portion of said stream
of air is heated and recirculated to retain heat and maintain a
relatively high dew point.
5. The method of popping grain comprising,
moving grain along a selected path while adding heat thereto until
said grain pops,
said path having a plurality of upwardly and downwardly directly
sections and extending in a direction transverse to said upwardly
and downwardly directed sections,
movement of said grain along said upwardly directed sections of
said path provided by entraining said grain in an upwardly moving
stream of air, movement of said grain downwardly affected by
gravity,
separating at least a portion of said popped grain from the
remainder of the grain at the upper end of upwardly directed
sections of said path, and
accelerating movement of said portion of popped grain relative to
the remainder of the grain to the next upwardly directed section of
said path.
6. The method of popping grain comprising,
preheating grain for a controlled period of time by adding thereto
substantially all of the sensible heat for vaporizing moisture in
the grain in a first area,
then rapidly heating the grain for a period of time less than said
controlled period to add any remaining sensible heat necessary and
the latent heat necessary to vaporize moisture in the grain and pop
the grain in a second area.
7. The method of popping grain comprising,
preheating grain by adding thereto at least a portion of the
sensible heat for vaporizing moisture in the grain in a
substantially saturated atmosphere in a first area,
then rapidly heating the grain to add any remaining sensible heat
necessary and the latent heat necessary to vaporize moisture in the
grain and pop the grain in a second area.
8. The method of claim 7 wherein the second area is a substantially
saturated atmosphere.
9. The method of popping grain comprising,
preheating grain by adding thereto at least a portion of the
sensible heat for vaporizing moisture in the grain,
then moving the grain along a selected path while adding thereto
any remaining sensible heat necessary and the latent heat necessary
to vaporize moisture in the grain and pop the grain,
said path having a plurality of upwardly and downwardly directed
sections,
movement of said grain along said upwardly directed section of said
path provided by entraining said grain in an upwardly moving stream
of air,
separating at least a portion of the popped grain from the
remainder of the grain at the upper end of upwardly directed
sections of said path, and
accelerating movement of said portion of grain to the next upwardly
directed section of said path.
10. The method of claim 9 wherein the air flowing along said
upwardly directed sections of the path is at a temperature greater
than grain-popping temperature,
and a portion of said air provides heat for preheating the
grain.
11. The method of claim 9 wherein air moving along said upwardly
directed sections of said path is heated and recirculated to
maintain it slightly under-saturated, and
wherein a portion of said air flows in direct heat exchange
relation with incoming grain and provides the heat for preheating
incoming grain in a substantially saturated atmosphere.
12. The method of popping grain comprising,
preheating grain by adding thereto a majority of the sensible heat
for vaporizing moisture in the grain in a first area,
then rapidly heating the grain to add any remaining sensible heat
necessary and the latent heat necessary to vaporize moisture in the
grain and pop the grain in a second area,
and then rolling the grain to pop any remaining unpopped grain.
13. The method of treating particular material of nonuniform
density or material which becomes nonuniform in density during
treatment comprising,
moving material along a selected path while adding heat
thereto,
separating at least a portion of the lighter density material from
the remainder of the material and accelerating its movement
relative to the remainder of the material,
and returning it to said path at selected downstream points
therealong to thereby reduce retention time of lighter density
material on said path.
14. The method of treating particular material of nonuniform
density or material which becomes nonuniform in density during
treatment comprising,
moving material along a selected path while adding heat
thereto,
said path having a plurality of upwardly and downwardly directed
sections,
movement of said material along said upwardly directed sections of
said path provided by entraining said material in an upwardly
moving stream of air,
separating at least a portion of the lighter density material from
the remainder of the material at the upper end of upwardly directed
sections of said path,
and accelerating movement of said separated portion of lighter
density material relative to the remainder of the material to the
next upwardly directed section.
Description
This invention relates to a method for treating material. The
method may be used to dry any desired product, such as barn manure,
alfalfa, lightweight aggregate, etc. or to pop grain.
The invention has been tested as a grain popper and the
specification will be directed to the problems of grain popping,
but it will be understood that it may be used in any situation
where heating of materials is desired.
Cattle are poor chewers. In order to make grain, such as milo,
readily available to the digestive system of cattle, it is
preferred to treat the grain in some manner which makes it readily
digestible.
Grain has been cracked by passing it through heavy rollers to break
up the grain and make it more readily available to the digestive
system. Grain has also been heated and rolled through heavy rollers
to make it more readily digestible. In this process heat is added
and the moisture present in the grain tends to soften the grain and
permit it to be rolled into flakes. Steam, at atmospheric or
elevated pressure, has been the usual source of heat in the flaked
grain process. While the flaked grain has been successfully used,
it leaves much to be desired. It takes about two weeks for cattle
to become accustomed to flaked grain. During this two weeks period
they do not eat as much as they do after they become accustomed to
flaked grain. Thus, their weight gain during this two weeks' period
is not up to par. Also, the moisture content of the grain varies.
Thus, the bulk density of the grain varies and the nutritional
value of a given volume of grain will vary. It also might be noted
that the grain will be affected by its maturity, moisture content
before being treated, etc.
Attempts have been made to pop grain, but insofar as is known these
attempts have been unsuccessful. Of course, grain can be popped in
a batch process, such as popcorn is popped for human consumption.
Such a process, however, is not economically feasible for large
scale feeding of cattle.
The principal problem in popping grain is that the temperature
utilized to pop is also the temperature at which the grain will
char and burn. Charring or burning breaks down the proteins and
destroys the food value of the grain. Thus, in the prior art
process of flaking, the temperature has been maintained at the
maximum of about 200.degree. F. This temperature is not sufficient
for popping. Popping occurs when the temperature of moisture within
a kernel of grain is raised above the boiling point to vaporize the
moisture and build up sufficient pressure to pop the kernel of
grain. Preferably the grain is raised to a temperature in excess of
the boiling point of moisture to insure popping of a high
percentage of the grain passing through a popping system. Obviously
this high temperature condition requires very close control of
conditions to minimize the problem of charring and burning. By very
close control of conditions, the grain may be popped and removed
from the popping zone with a substantially constant moisture
content, even though the physical properties of the grain entering
the system may vary in moisture content, maturity, etc.
While it has been generally thought that the grain could not be
successfully popped in a continuous process, the method disclosed
herein has been used to successfully pop grain on an economical
basis. In fact, it has been found that the equipment utilized in
popping grain will cost approximately 50 percent of the equipment
utilized in steam flaking of grain. It has also been found that the
cost of operating popping equipment in accordance with this
invention compares very favorably with steam flaking now used by
the industry. The cost will generally run less than 50 percent and
in comparison with high quality steam flaking the cost of obtaining
high quality popped grain may be as low as one-fourth of the cost
of high quality steam flaked grain.
Preliminary studies indicate a greater weight gain per pound of
feed of popped grain versus flaked grain.
In the drying of alfalfa, uneven drying of leaves and stems
presents a problem. If leaves are accelerated relative to the
heavier stems in passing through a heater, this problem is
minimized.
An object of this invention is to provide a method for continuous
popping of grain.
Another object is to provide an inexpensive method for the
continuous popping of grain.
Another object is to provide a method for continuous popping of
grain wherein the moisture content of the resulting product is
relatively high and is constant to give a uniform product.
Another object is to provide a method for treating material in
which the material is heated and at least a portion of the heated
material is separated from the remainder of the material and
accelerated to quickly remove it from the heat zone.
Another object is to provide a method which may be used to pop
grain, to heat alfalfa, to heat and expand lightweight aggregate
such as perlite, to dry manure, etc.
Another object is to provide an inexpensive method for heating
material, such as lightweight aggregate, which is much less
expensive to manufacture and to operate than the conventional
rotary kiln.
Another object is to provide a method for heating material, such as
alfalfa, in which leaves are accelerated relative to stems in its
movement through the heater, and thus the tendency for uneven
drying at the drying temperature is minimized.
Another object is to provide a method for popping grain which also
may be utilized at the feed lot for drying manure to provide a
saleable product.
Another object is to provide a method for treating material in
which the lighter density material which may be involved in the
feed material, or which may become lighter during heating, is
accelerated relative to the heavier density material to quickly
remove it from the heat zone.
Another object is to provide a method for popping grain when the
heat for popping the grain is provided by heated air.
Another object is to provide a method for popping grain wherein
grain is popped and at least a portion of the popped grain is
immediately separated from the unpopped grain and accelerated to
quickly remove it from the heat zone.
Another object is to provide a method wherein grain is popped by
heat and conventional rollers are used only to pop the small
percentage of grain which passes through the grain popper without
popping.
Another object is to provide a method to slowly add sensible heat
to grain and then rapidly add the latent heat to grain to effect
the popping thereof.
Another object is to provide a method as in the preceding object in
which the heat is added to the drain in a substantially saturated
atmosphere to avoid dehydrating the grain.
Another object is to provide a method in which an air heating
system for popping grain is provided and heated substantially
saturated air is economically utilized.
Another object is to provide a method for popping grain utilizing a
preheater which keeps grain in substantially continuous contact
with heated substantially saturated air and slowly adds sensible
heat of popping to grain to avoid drying out the grain.
Another object is to provide a method as in the preceding object in
combination with a heater for adding any remaining sensible heat
and for adding the latent heat of popping rapidly to pop grain
before vapor can escape through the shell of the grain.
Another object is to provide a method in which grain is popped by
heated air and retention time in the popper can be regulated to
accommodate different grains or grains having different physical
properties in a single grain popper.
Another object is to provide a method utilizing heated air to pop
grain in which the popped grain is removed from the popping zone
before it has a chance to char.
Another object is to provide a method as in the preceding objects
in which material other than grain is treated by the same method,
or in which grain is treated by the same method but is not
popped.
Other objects, features and advantages of the invention will be
apparent from the drawings, the specification and the claims.
Referring now to the drawings, wherein an illustrative embodiment
of this invention is shown and wherein like numerals indicate like
parts:
FIG. 1 is a view in side elevation of an apparatus contructed in
accordance with this invention with parts broken away to illustrate
details of the apparatus;
FIG. 2 is a top plan view of the apparatus;
FIG. 3 is an end elevational view of the apparatus;
FIG. 4 is a fragmentary view along the line 4--4 of FIG. 1
illustrating flow of grain and air through the heater and separator
section of the apparatus;
FIG. 5 is an isometric view of the heater and separator portion of
the apparatus with parts broken away to illustrate details;
FIG. 6 is an end view through the duct portion of the apparatus
with the inner plate 49 omitted;
FIG. 7 is a side view of a fragment of the duct portion of the
apparatus; and
FIG. 8 is an end view of the preheater auger.
In practicing the process of this invention, grain is conducted to
a first area in which sensible heat is added to the grain. Thus, in
the first area the grain and the moisture therein is brought up to
a temperature approaching the boiling point of moisture in the
grain. Preferably the atmosphere in this area is saturated, or
nearly saturated, so that moisture is not removed from the grain in
any substantial amount. To give even heating, it is preferred that
the grain be constantly agitated in this area so that even heating
will occur.
After the grain is preheated it is then moved into a final heating
area in which any remaining sensible heat needed is added, and the
latent heat needed to vaporize moisture in the grain is added. Here
again, it is preferred that the grain be constantly agitated so
that there are no stagnant areas. The process is preferably closely
controlled so that the popped grain is removed from the heated area
before it chars.
In order to quickly remove popped grain from the heater before it
chars, it is preferred that there be some separation of the popped
grain from unpopped grain and acceleration of flow of the popped
grain through the heater area. In accordance with one aspect of
this invention, random kernels of grain which have been popped are
separated from the remainder of the grain at a plurality of points
along the path of travel of the grain through the heater area and
accelerated relative to the remainder of the grain to thus
accelerate travel of grain after it is popped through the heater
area to remove it therefrom before charring.
Preferably, the method of handling the grain in the heater area is
one employing upwardly flowing currents of air which serially raise
the grain. After the grain is raised, the air and grain are
separated and the grain is permitted to fall in the area. The
circulation of air is preferably such that some popped grain is
immediately returned to the next upwardly flowing current of air,
while the remainder of the grain is retained in the area for a
longer time. Thus, random kernels of popped grain are accelerated
relative to the remainder of the grain to reduce their retention
time in the heater area.
It is further preferred that the currents of air flow generally
parallel to each other and at slight angles to the vertical so that
grain introduced into one end of the heater area will be lifted by
the upwardly flowing first current of air and dropped so that it
will be picked up by the second current of air. This process is
continued until the grain reaches the end of the heater area and is
discharged.
To avoid drying out of the grain, it is preferable that the heater
area be maintained in a substantially saturated condition. Thus, as
the grain passes through the preheater, it is heated without an
excessive loss of moisture and, in like manner, the grain passing
through the heater is treated without an excessive loss of
moisture.
After the grain has been popped, it is preferably rolled between
rollers to pop any remaining kernels of grain which have not been
popped. The rollers will rupture the shell of the kernel and permit
the vapors under pressure therein to pop the kernel.
Referring now to the drawings, flow of grain is indicated by arrows
having dashed tails and flow of air is indicated by arrows having
solid tails.
Grain such as milo enters the apparatus through the feed hopper
indicated generally at 10 and is introduced into the preheater
indicated generally at 11, wherein sensible heat is added to the
grain to prepare it for popping. The grain passes from the
preheater to the heater indicated generally at 12, wherein any
remaining sensible heat is added, and the latent heat for
vaporization of moisture in the grain is added to pop the grain.
Popped grain passes along the conveyor indicated generally at 13 to
the rollers indicated generally at 14 wherein the grain is rolled,
and any grain which has not popped will pop after passing through
the rollers.
Hot air for heating the grain is provided by the air heater
indicated generally at 14. Air passes from 14 to the heater 12 and
in part returns to the air heater via conduit 15. A portion of the
air passes through the conduit 16 to the preheater 11 and thence
out of the system through conduit 17.
Considering now in detail the several components of the apparatus,
the grain is fed from a suitable hopper not shown through the
apparatus 10. This apparatus includes a rotating shaft 18 having a
plurality of vanes 19 thereon which cooperate with the shell 21 to
substantially prevent upward flow of air while moving the grain to
the outlet 22. A control member 23 in the form of a slide or gate
valve may be utilized to control flow of grain into the system.
This control is normally full open during operation of the system,
but will be partially closed during startup to limit flow of grain
into the apparatus while it is coming up to normal operating
temperature.
The incoming grain first passes through the dust remover indicated
generally at 20. The dust remover includes a tubular housing 25
which has therein an upright conical member 24 which forces the
grain to drop through a narrow annulus between the housing 25 and
the conical member 24. Upwardly flowing air moves countercurrent to
the descending grain and removes dust, dirt and like contaminants
from the grain.
The air from the preheater is normally completely saturated at this
point and there is a tendency for the saturated air to wet the
incoming grain and cause sticking problems. To avoid this
difficulty, a plurality of holes 26 are provided in the housing 25
to draw fresh air into the system and reduce the dewpoint of air
from the preheater. To insure mixing, a sleeve 27 is secured to the
housing above the holes 26 and extends downwardly to approximately
the lower extremity of the holes. The bottom extremity 27a of the
sleeve 27 inclines inwardly and downwardly in frusto-concial shape
to force incoming fresh air to flow downwardly about the bottom of
the frustoconical section 27a of the sleeve and mix with the
incoming hot air from the preheater. The mixed air has a dewpoint
less than the air temperature so that the tendency of grain to
stick is reduced.
The air exhausts through conduit 17 and the blower indicated
generally at 28. The blower 28 provides a suction on the system to
assist in maintaining air circulation in the desired manner.
The cleansed grain drops into the preheater 11. From the end view
of FIG. 3 it will be noted that the bottom of the preheater is
semi-circular. A ribbon auger driven by a motor (not shown) conveys
grain through the preheater. The ribbon 29 of the auger is carried
on the arbor 31 in spaced relationship thereto by a plurality of
support members 32. The level of the grain in the preheater will be
high enough to be engaged by the ribbon 29 and moved to the left
hand side where it passes through the conduit 33 to the main
heater.
Means are provided on the auger for lifting and dropping grain in
the preheater to keep the grain in constant agitation and
continuously expose the grain to flow of air through the preheater.
In order to accomplish this objective, shovels are provided on the
auger which lift the grain and drop it from above the normal grain
level. These shovels may be provided by longitudinal angle iron
shaped flanges 34 extending radially from the ribbon 29. Note FIG.
8 wherein an end view of the auger is shown. It will be apparent
from this figure that as the auger rotates, grain is picked up by
the free leg 34a of the flange, lifted and dropped down through the
auger where it falls through the air passing through the
preheater.
In the preheater heat is slowly added to the grain to provide the
sensible heat of vaporization of moisture within the grain. In
order to minimize drying of the grain by the hot air, it is
preferred that the air passing through the preheater be maintained
as close to saturation as possible. As the air flows from the air
inlet to the air outlet of the preheater, it will of course be
cooled by the relatively cool grain. Thus, to avoid excessive
condensation of moisture it will be recognized that air entering
the preheater will be slightly under-saturated and, as its
temperature is cooled by contact with the grain, it will become
substantially saturated by the time it reaches the end of the
preheater. If the air entering the preheater is saturated, then as
it is cooled by the grain moisture will condense on the grain. So
long as this is not excessive and sticking of grain is not a
problem, this is not objectionable.
In the main heater section of the apparatus the grain is further
heated to provide any additional sensible heat necessary plus the
latent heat necessary to vaporize moisture in the grain to effect
popping of the grain. The main heater section includes a body 35 to
which the conduit 33 is connected. Reference is particularly made
to FIGS. 1, 4 and 5 for an understanding of the operation of this
portion of the apparatus.
Within the housing 35 there is provided a bucket wheel indicated
generally at 30. This wheel has a number of buckets thereon for
catching grain, as will be more fully explained hereinbelow, and
providing retention time in the main heater section. These buckets
may be provided by longitudinally extending channel iron-shaped
members 36 which are supported on the wheel by spaced radially
extending plates 37.
In order to prevent flow of air directly from the main heater
section to the preheater, an air valve is provided. In FIG. 5, it
will be noted that an end plate 37 is spaced from the end 38 of the
housing. This plate has a slight clearance with the trough 39
immediately below the wheel 30. The wheel also has a slight
clearance with a complementary plate 41 above the wheel. The inlet
33 communicates with the wheel between the trough 39 and plate 41.
The bottom end of inlet 33 is complementary to and spaced slightly
from the two adjacent plates 37 (FIG. 5). A plurality of vanes 42
extend radially from the wheel and have slight clearance with the
trough 39 and plate 41. At least one of vanes 42 is always in
contact with trough 39 and plate 41 to inhibit flow of air. Thus as
grain falls down chute 33 it falls into the space between the vanes
42 and, as the wheel 30 rotates, the vanes sweep the grain out of
trough 39 and onto the inclined shelf 43. In this manner grain
enters the main heater and air is prevented from leaving the heater
without first passing through the separator indicated generally at
44.
The surface 43 is at an angle which is greater than the angle of
repose of the grain. This will permit the grain to fall down the
surface. However, in order to provide retention time in the
chamber, the surface 43 should have a substantial angle with the
vertical.
At the bottom of the surface 43 there is provided a breaker wheel
45 which will break up any conglomerates of grain falling down the
surface. This wheel 45 extends the full length of the main heater
12.
Means are provided for establishing a path of grain flow from end
to end of the heater body 35. Preferably this path has upwardly and
downwardly extending sections and at least some popped grain is
separated at the upper ends of sections of the path and accelerated
to the next upwardly extending section of the path. In the
preferred embodiment the wheel 30 and shelf 43 provide the
downwardly extending section of the path.
The upwardly extending portions of the path utilize air to lift
grain and, before proceeding to the duct system, the source of air
for the duct system will be noted.
Hot air under slight pressure is present in the conduit 46. This
conduit communicates with an orifice 47 at the extreme lower end of
the shelf 43. The lower section 43a of shelf 43 is slidably
adjustable to regulate the size of the orifice 47. Bolt 48 is
provided for fastening the slidable portion 43a in the desired
position. This adjustment is provided to avoid manufacturing
tolerance problems.
The small orifice 47 extends the full length of the heater and thus
serves as a distributor of the air in conduit 46 and reduces the
pressure of air passing therethrough to a slight negative pressure.
This results in a substantial increase in the velocity of the
air.
Duct means indicated generally at 48 is provided adjacent the
orifice 47. One surface 49 of the duct means extends to a point
just above the orifice 47 and cooperates with the slidable plate
43a to provide a bottom opening at 51 from the main heater. The
outer wall 52 of the duct means is spaced from the wall 49 to
provide a narrow passage extending upwardly for conducting air to
an upper section of the main heater chamber 53. Thus, air passing
through the orifice 47 increases in velocity and entrains grain
falling down the shelf 43 and carries the entrained grain up
through the duct 48 to the upper portion of the chamber. At the
upper portion of the chamber, the duct has slowly changed
directions from the vertical to the horizontal direction provided
by plate 54. Preferably, the duct ends in a plate 55 which extends
downwardly so that the air moves up the duct 48 beginning in a
vertical movement and then scribes a circle to finally be directed
downwardly and to the left as shown in FIG. 4. It will be noted
that the terminal portion 50 of the duct is over the bucket wheel
30 and directs grain down toward the wheel. At this point the air
flow divides. A small portion of the air flows back down the
chamber 53 due to the negative pressure at the orifice 47. This
flow of air is important as it will tend to carry with it random
kernels of grain which have been popped and are relatively light in
bulk density. Thus a portion of the popped grain will be
accelerated in its movement through the main heater, as will appear
hereinafter.
In FIG. 7 a form of duct is shown in which the plate 49 has been
omitted. Due to the velocity of flow in the duct system the plate
is not necessary, particularly with light material such as milo.
When the plate is omitted the popped grain will tend to fall out
along the length of the duct system and reduce retention time of
the popped grain.
The principal portion of the air leaving the duct 48 moves upwardly
to the upper section of the chamber 53 and passes therefrom to the
separator indicated generally at 44. A small amount of popped
grain, dust, etc. will normally be entrained in this air
stream.
In order to give retention time in the main heater, at least a
portion of the grain passing up through the duct 48 is caught in
the buckets 36 on the wheel 30. Of course, a portion falls through
the space between buckets onto the trough 39 and additional
retention time results. Some of the grain will probably fall
directly onto the surface 43.
Means are provided for causing the grain as it travels in the
circle of bucket wheel to bottom outlet 51, through duct 48 and
back to the wheel section to move from the inlet end of the main
heater to the opposite end of the main heater where it is
discharged through the outlet 56 (FIG. 1). This movement may be
provided in any desired manner. In the preferred form of apparatus
as shown herein, this movement is provided by the duct means 48.
Referring particularly to FIG. 7, it will be noted that duct means
48 includes a plurality of generally vertically extending but
slightly inclined dividers 57. It will be seen from FIG. 7 that
grain entering at the bottom of the duct means in effect flows
through a plurality of ducts which are arranged in a row and the
row inclined slightly relative to the vertical so that grain is
discharged in a vertical plane which is closer to the outlet 56
than the point at which the grain entered the duct system.
Grains of different physical properties require different lengths
of time in the main heater section. Control of this time may be
provided by making the upper portion of the dividers 57 adjustable.
Thus the upper sections 57a are hinged at pivot 58. Each divider is
connected to a rod 59 which is reciprocal by rotation of the nut 61
on the threaded end 62 of the rod 59. Also, the speed of rotation
of the bucket wheel 30 may be varied if desired to control
retention time of grain in the chamber 53.
From the above explanation, it will be apparent that grain enters
at one end of the bucket wheel 30 and is swept by the bucket wheel
to the inclined surface 43 without any substantial amount of air
flowing up the conduit 33. The grain tumbles down the inclined
surface 43, is broken up, if necessary, by the breaker wheel 45 and
leaves the chamber at the bottom outlet thereof. Air then entrains
the grain and passes it up the duct system 48 and drops the grain
out at a point above the bucket wheel. In the process of moving up
the duct system, the grain is of course heated by the hot air which
is in direct heat exchange relationship therewith. The stream is
forced to turn and finally exit from the duct system in a slightly
downward direction, directing the grain downwardly in the direction
of the bucket wheel. Popped grain will have a lighter bulk density,
and a small portion of this grain will be carried out with the main
air stream. Another portion of this popped grain will be carried
back downwardly through the chamber 53 in a portion of the air
stream and delivered immediately to the outlet 51. The remaining
grain will be deposited on the wheel or dropped through the wheel
onto the trough and retention time is provided by the rotation of
the trough. While some unpopped kernels of grain may drop directly
onto the inclined surface 43, the unpopped grain for the most part
will have sufficient velocity to be carried onto the wheel and
trough and only popped grain will tend to follow the air stream
back down chamber 53. Thus, random particles of popped grain are
accelerated through the system. As the grain makes the circuit of
the duct system, it is moved each time by the inclined individual
ducts from the inlet toward the outlet of the chamber and finally
drops into the outlet 56.
It will be noted that the outlet 56 is over one end of the auger 12
which conveys grain to the outlet 63. The grain passes from the
outlet 63 to a pair of rollers 64 which are conventional in form
but which require substantially less horsepower than rollers
heretofore employed in flaking grain. In flaking grain, substantial
horsepower is required as the grain has not been popped. In the
instant process, substantially all the grain will have been
previously popped. A small percentage of grain may, however, pass
through the machine without being popped. This grain, however, will
have been softened by the heat and moisture, and as it passes
through the rollers the shell of the grain will be ruptured and the
grain will pop as it passes through the rollers. The rollers will
also tend to flake the popped grain, but this is not
objectionable.
It should be noted that the air stream heats the surface 43 as it
passes through the duct 46 and also supplies heat through the duct
system 48 and directly by circulating through the chamber 53. As
the grain pops, moisture is released to increase the dewpoint of
the hot air. By recirculating the air stream, at least in part, the
dewpoint of the air may be brought up to a point where it
approaches saturation, and thus excessive moisture loss from the
grain is avoided. For instance, the chamber 53 may be operated at a
temperature of 650.degree. F. with a dewpoint of about 550.degree.
F.
With these high temperatures, it will be appreciated that the grain
must pass through the system very rapidly. With milo it has been
found that the grain should remain in the preheater about 1 minute
and in the main heater section about 1/2 minute.
Referring now to the air stream, the burner system 14 includes a
suitable burner shown generally at 65 fed preferably by a natural
gas through conduit 66 and air through the inlet 67. Preferably the
burner is regulated to be operating in an oxygen-poor atmosphere.
The burning gases pass into the refractory-lined tube 68, impinge
upon and pass into the refactory-lined shield 69. This shield keeps
the blower indicated generally at 70 from seeing any of the hot
gases. Recirculated air through the conduit 15 passes into the
annulus between the exterior wall 71 of the burner assembly and the
refractory-lined tube 68. This incoming air cools the tube 68 and
mixes with the newly heated gases as it passes around the shield
69. The gases are further mixed in the blower 70 and are directed
upwardly from the blower 70 through the conduit 72 into the conduit
46 as best shown in FIG. 4. The hot, moist gases are at a slight
positive pressure in the conduits 72 and 46.
The air, as previously explained, flows up through the duct 48 and
circulates through chamber 53 and all of the air ultimately passes
through the top of chamber 53 and to the separator 44. As indicated
by the arrows, the air passes through a narrow throat 73 and then
into a large area 74 and impinges against the wall 75 of the
separator section. In the chamber 74 most of the solids which are
entrained in the air stream fall out and fall onto the conveyor 13
to join the popped grain falling through the outlet 56. The air
then passes into the separator and, due to the internal
substantially concentric tube 76 which runs the length of the
separator, the air circulates in counter-clockwise motion. The
outlets from the separator are at the ends of and inside of the
inner circular member 76 and thus the air must reverse in direction
and pass through the narrow opening 77 to reach the inside of the
member 76 and exhaust from the separator. This reversal in
direction will assist in knocking out any solids which may be
entrained. Also, the centrifugal action of the air stream flowing
about the outer shell 78 of the separator 44 will tend to cause
solids to fall out, and these solids will fall out through the gap
79 and ultimately find their way into the auger 12. It will be
noted that the shell 78 of the separator terminates at point 81 and
a partial plate 82 is provided which is closer to the center of the
separator than the terminal point 81 of the outer shell, thus any
solid particles will fall through the opening 79 rather than be
carried up onto the higher shelf provided by the plate 82.
From the right-hand end of the separator as viewed in FIG. 1, the
principal portion of the air passing through the separator is
carried by the conduit 15 to the burner 14 to recirculate in the
system to maintain a high dewpoint, and to maintain a high
efficiency in the heating system. A small portion of the air leaves
the outer end of the separator 44 through the conduit 16 and passes
into the preheater 11. This air, as previously explained, preheats
the grain and then passes to the outlet conduit 17 from which it is
exhausted.
While the above discussion has been directed to the popping of
grain, it will be appreciated that the system may be utilized to
treat grain other than by popping. For instance, by running the
system at a lower temperature, grain could be flaked. However, it
is expected that the advantages of popped grain are such that under
normal circumstances the grain would be raised to the elevated
temperature needed for popping. Of course, the system may be used
to dry any desired product.
One of the problems present at a feed lot is disposing of barn
manure. This system may be used to dry the manure, sterilize weed
and grass seeds to give a saleable dry product. By thus disposing
of the manure, the problem of contamination of the water table
below the feed lot is materially reduced.
Preferably, temperature sensors are provided throughout the system
to assist the operator in controlling the operation. Difference in
physical properties of the grain may be compensated for by changes
in temperature, speed of rotation of the bucket wheel, or
adjustment of the duct system 48.
It will be appreciated that the preheater permits grain to be
slowly brought up to a temperature close to that for popping, and
then the main heater section can rapidly bring the temperature up
to the popping level. This rapid raise in temperature prevents a
relatively large pressure drop through the shell to insure a good
pop. The unit may be used to provide a grain of uniform physical
properties, even though it is not necessary to pop it to make it
readily digestible. For instance, corn or oats are readily
digestible. They are, however, of nonuniform physical properties
due to degree of maturity, moisture content, etc. If desired to
obtain a uniform grain, they may be passed through the system and
rolled to obtain a substantially uniform product. As very low
horsepower is needed to operate the rolls after grain has been
treated in the heater, the cost is relatively low.
As noted at the beginning of the specification, the system may be
used to dry any desired material. For instance, the method and
apparatus may be utilized to expand lightweight aggregate, such as
perlite, and thus substitute it for the conventional expensive
rotary kiln.
Materials of different densities may be successfully dried with
much fewer attendant problems than in presently known drying
methods. The method and apparatus is particularly useful in those
situations in which the feed material is of different density, or
in which the density of materials is changed in heating. The
acceleration of the light density material, which will usually tend
to burn faster than the heavier density materials, speeds it
through the system and thus reduces the tendency to burn.
The foregoing disclosure and description of the invention are
illustrative and explanatory thereof and various changes in the
size, shape and materials, as well as in the details of the
illustrated construction, may be made within the scope of the
appended claims without departing from the spirit of the
invention.
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