U.S. patent number 3,603,001 [Application Number 04/807,802] was granted by the patent office on 1971-09-07 for agricultural dehydrating and cooling system.
This patent grant is currently assigned to N/A. Invention is credited to Gerald D. Arnold, John B. Arnold.
United States Patent |
3,603,001 |
Arnold , et al. |
September 7, 1971 |
AGRICULTURAL DEHYDRATING AND COOLING SYSTEM
Abstract
A furnace for providing dehydrating gases has its flue connected
in series with a multiple-pass dehydrating drum compartment by
longitudinal radial partitions to promote efficient intimate
exposure of material to dehydrated gas by subdividing both the gas
and the material into narrow streams while still providing the
tumbling which results from drum rotation. The light output of the
drum is delivered through a settling chamber into a cyclone
separator which has its gas discharge port connected to a blower
that subjects the chamber and drum and furnace to vacuum. The light
solids are then recombined with heavy solids before discharge.
Discharge of solids without access of air is controlled by a rotary
valve which has generally radial vanes protected from breakage by
provision of angularly yieldable end portions.
Inventors: |
Arnold; Gerald D. (Ettrick,
WI), Arnold; John B. (Memphis, TN) |
Assignee: |
N/A (N/A)
|
Family
ID: |
25197202 |
Appl.
No.: |
04/807,802 |
Filed: |
March 17, 1969 |
Current U.S.
Class: |
34/136; 55/432;
222/368 |
Current CPC
Class: |
F26B
11/049 (20130101); F26B 11/026 (20130101) |
Current International
Class: |
F26B
11/04 (20060101); F26B 11/00 (20060101); F26B
11/02 (20060101); F26b 017/00 () |
Field of
Search: |
;34/109,128,136,135,79,57,57D ;55/267,430,459 ;222/368 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Matteson; Frederick L.
Assistant Examiner: Streule; Theophil W.
Claims
We claim:
1. A dehydrator comprising a rotatable drum having an inlet at one
end and an outlet at the other, a suction fan for effecting flow of
dehydrating gases and material through the drum, a cyclone
separator connected in series between the drum and the fan for
segregating dehydrated material from the gases which have acted
thereon, said separator including a tapered separating chamber and
a discharge port for solids opening from the smaller end thereof, a
normally closed rotary discharge valve controlling flow through
said discharge port, said valve comprising a rotatably mounted
shaft and outwardly projecting vanes mounted thereon, each such
vane having a vane extension in hinged connection therewith, means
for biasing said extension to project outwardly from the vane to
which it is hinged, and a valve chamber substantially closed by the
several extensions when they are in the normal position to which
they are biased, each such extension being yieldable upon its
hinged connection to pass objects foreign to the material being
dehydrated.
Description
BACKGROUND OF THE INVENTION
Systems on the general order of that herein disclosed are old but
the material being dried in a multiple-pass drum tends to
concentrate at one side and both ends of the drum as the result of
rotation thereof, the other side of the drum being thereby left
open for the passage of dehydrating gas which has not fully acted
upon the material.
It is also known to draw the dehydrating gas and the solids through
the drum under partial vacuum, the convection current being created
by a fan at the discharge end of the system.
SUMMARY OF THE INVENTION
The invention herein disclosed makes improved use of the
dehydrating gas by dividing both the solids and the gas into
components which traverse segmental axial passages between
longitudinal partitions in the drum and about the end. These assure
that substantially all portions of the dehydrating gas will be
tumbled while fully exposed to the produce or grain or other solids
to be dried.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a general view in side elevation of a dehydrating system
embodying the invention.
FIG. 2 is an enlarged detail view in transverse section through the
valve which controls the discharge of solids from the
separator.
FIG. 3 is a fragmentary view in axial section through the drum on a
considerably enlarged scale.
FIG. 4 is a further enlarged detail view taken in section on the
line 4--4 of FIG. 3.
FIG. 5 is a view taken in section on the line 5--5 of FIG. 3.
FIG. 6 is a detail view taken in section on the line 6--6 of FIG.
3.
FIG. 7 is a fragmentary detail view showing a modified partition
and baffle arrangement.
FIG. 8 is a fragmentary detail view partially in section and
partially in perspective showing a modified flight arrangement.
DETAILED DESCRIPTION
The nonrotatable furnace drum 14 has a generally tangential fuel
and air inlet at 16.
A flue pipe 20 leads toward the dehydrator drum head 22 at the
inlet end 24 of the rotatable mounted drum 26. A motor 25 rotates
the drum on supporting rollers 190. A rate changer 27 preferably
intervenes in the drive from the motor to the drum to enable the
operator to control the speed of drum rotation. The material to be
dehydrated is elevated by conveyor 28 and delivered into a hopper
30 which communicates through a rotary valve 32 with a throat 34
through which the dehydrating gas from furnace 14 enters drum 26.
The entire system is preferably maintained under partial vacuum by
an exhaust fan 54.
A spray nozzle 36 has a water supply connection 38 which delivers
water directly onto the produce 40 on conveyor 28. The amount of
water is controlled with discharged gas temperature as explained in
Arnold U.S. Pat. No. 3,360,868 to prevent scorching of the material
in the drum while assuring complete dehydration thereof. In
addition to preventing scorching, the moisture and heat together
are effective in degradating pesticides and antibiotics on the
produce, whereby to protect animals and milk from
contamination.
Details of the drum construction will be explained later.
Dehydrated material issues from the outlet end 42 into settling
chamber 43 from which the pipe 44 carries the dehydrating gas and
the lighter entrained dehydrated solids upwardly to the tangential
inlet 46 of a centrifugal separator 48. In its upward movement, the
dehydrating gas will tend to drop out not only the heavier
dehydrated material but also any foreign matter such as stones or
iron. All such material will be received by conveyor 50, recombined
with light material from the separator 48 and discharged downwardly
by gravity through the rotary discharge valve 51 onto discharge
conveyor 50.
The gases are withdrawn from the cyclone separator 48 by means of
said exhaust fan or blower 54 operated from motor 56 through a
speed controlling rate changer 58. The gases discharge into the
atmosphere at 60. The solids pass through a rotary valve 51 onto
conveyor 50 (as previously described). This conveyor is sealed from
the atmosphere by housing 75 from which solids are delivered
through rotary valve 76. Discharge is effected on conveyor 78.
THE DRUM CONSTRUCTION
The drum 26 as shown is a rotatable triple-pass drum. There is an
inner shell 80, an intermediate sleeve 92, and an outer shell 126.
The clearance between the inner shell 80 and the throat 34 is
sealed against the admission of atmospheric air by a floating
sealing ring 112 bearing on throat 34 and guided by suspension from
brackets 114 as best shown in FIG. 3. The seal ring 112 is held by
partial vacuum against the end of inner shell 80.
The dehydrating gas and the entrained material 40 to be dehydrated
enter through the throat 34 into the inner tubular shell 80 which
is divided by short radial partitions 82 into arcuate segmental
passages 84. These passages are further divided by flights 86
riveted or welded to the inner shell 80. During drum rotation the
partitions 82 and the flights 86 lift the materials to be
dehydrated and drop it across the path of dehydrating gases
traversing the narrow segmental passage 84 longitudinally of the
drum. Some of the material drops repeatedly across the center
portion of the drum where it is exposed to the gases passing
through the center. However, it will be noted that practically none
of the dehydrating gases will escape exposure of the material
thereto. This exposure of the gases and the material to each other
continues in successive drum traverses.
Once the material enters one of the passages 84 it is segregated
from other material all the way through the intermediate and outer
drums.
The central tube or shell 80 has its end 88 sleeved in a ring 188
supported by the gussets 118, one of which is shown in FIG. 4.
Similarly the intermediate drum or shell 92 is supported by gussets
127 and ring 192 from the outer shell 126 (FIGS. 3 and 4). The
dehydrating gas and the material sweep around the end 88 into the
passages 90 between the inner shell 80 and the intermediate shell
92 (FIGS. 3 and 5). Generally radial partitions 94 delineate
arcuately segmental passages 90 which extend longitudinally of the
drum between sleeve 92 and the inner shell 80. Into each of the
passages 90 extend flights 96 from the inner shell 80, flights 98
from the partitions 94 and flights 100 from the intermediate sleeve
92. The flights preferably are backwardly pitched as shown in FIG.
8 and have flanges 87 riveted or welded at 89 to the respective
shell or sleeve.
Radial partitions 94 have outer margins 104 and inner margins 106,
respectively slidable in channels 108 provided by the fittings 110
attached to respective shells. The ends of these partitions line up
with the gusset plates 118 which, in turn, are in the same plane as
the partitions or flanges 82 in the interior of the inner shell 80.
They also line up with partitions 119 which subdivide the inner
section 23 of the end 22 of the dehydrator. Bolts 120 connect the
inner section 23 with the outer section 21 of the end member 22.
When these bolts are removed, the central cylinder 80 with the
partitions 82 on the interior thereof and the partitions 94 on the
exterior thereof may be axially removed unitarily from the rest of
the dehydrator. However, the bolts 124 extending through gusset
plates 128 in a radial direction are provided with nuts 131 in the
apertures 130 of gusset plate 118 to prevent withdrawal.
Instead of attaching flights 98 to the partitions 94 as shown in
FIG. 5, it is possible to form these partitions as shown at 95 in
FIG. 7 with bodily offset portions 980 which perform the function
of flights 98. In any case, the outer and inner margins 104 and 106
of the partitions are preferably slidable in channels 108 provided
by the fittings 110 attached to the respective shells as best shown
in FIG. 7. (See, also, FIG. 5)
Partitions 134 circumferentially spaced from each other and
disposed radially between the intermediate sleeve 92 and the outer
shell 126 provide segmental passages 132 into which flights project
in the same manner as between the inner shell 80 and the
intermediate sleeve 92. Material which has traversed the
intermediate passages 90 is guided by the curved end to enter the
external passages 132, these being traversed from left to right as
viewed in FIG. 3.
Aligned with the partitions 134 between passages 132 are the gusset
plates 128 referred to above. These are aligned, in turn, with
partitions 140 between the conical end wall 138 and the conical
interior baffle 136 (FIG. 3). This baffle guides the material and
dehydrating gas to throat 139 which is loosely telescoped over the
delivery pipe 44 above mentioned. Encircling this pipe is a sealing
ring 112 identical with the sealing ring at the inlet. Ring 112 is
seated against flange 135 on the end of pipe 44. The ring 112 is
held to the flange 135 by partial vacuum produced within the system
by the suction of the blower 54. The ring floats under guidance of
the chains 149 which may be connected, for example, with the
brackets 114 on throat 139.
In practice, the solids pass downwardly through the cone 150
because of the fact that the discharge pipe 172 is normally closed
against air admission, being equipped with a rotary valve 51. As
will be noted in FIG. 2, the liner for the valve housing 51 is
eccentric with the housing where it has a lip portion at the point
where it connects to a throat or discharge pipe 172. Elsewhere the
valve vanes 182 are in close proximity to the liner but they have
increased clearance from the liner at the lip where the material
enters the housing so that such material will not be sheared by the
vanes at this point. This is of particular importance when the
material consists of grain such as corn. But for the described
construction, the corn might be cracked by the vanes.
THE ROTARY VALVE
A power driven shaft 176 carries fixed vanes 178 which are not
radial but rearwardly inclined and which extend only part way
outwardly from the shaft. At corresponding points, each of these
vanes is provided with a hinge 180 for a yieldable vane extension
182 which is normally biased into alignment with the vane 178 but
is yieldable backward. The direction of rotation is indicated by
arrow 184. The spring 186 holds each of these vane extensions in
its retracted position as shown but each is yieldable in a
clockwise direction as viewed in FIG. 2, against the bias of spring
186 if the blade is impacted by iron or other hard material which
may reach this point in the apparatus, the object being to avoid
damaging the valve. As shown in FIG. 2 one of the vane extensions
is shown in dotted lines in a position to which it has yielded
against the bias of its spring 186.
In accordance with routine practice, the outer shell 126 carries
peripheral riding rings 188 which are supported on rollers 190 to
facilitate rotation of the drum 26. The gussets 128 at the outlet
end of the drum carry rings 192 which support the intermediate
sleeve 92, similar support being provided at the inlet end of the
drum by rings 194 supported by gussets 196 from the outer shell
126. The intermediate sleeve 92 is axially slidable telescopically
into and from the ring 192, being held in position during normal
use by the bolts 124 already described. The mounting of the inner
shell 80 which supports its weight from the riding rings 188 is
similar, the gusset 118 between the inner shell and the
intermediate sleeve providing support for the rings 188 as already
described. The ring 200 into which the inlet end of the inner shell
80 is sleeved is carried by the head 22 which supports it directly
from the riding ring 188 which is closest to the inlet of the
dehydrating drum.
The parts are readily assembly by telescopically sleeving them
together as already described. It is equally easy to disassemble
them simply by removing the inner shell 80 from the internally
projecting partitions 28 and disconnecting the bolts 124 so that
the intermediate sleeve can be withdrawn through the previously
disassembled section 23 of the head 22 at the inlet end of the
drum.
In practice, the dehydrating gases include products of combustion
and additional air. They are very hot when they issue from the
furnace and traverse the throat 34 in which the material 28 to be
dehydrated is introduced through the valve 32 with its surfaces
thoroughly wet by the water directed upon them through the spray
nozzle 36. This water is immediately evaporated and turned into
steam at temperatures above 212.degree., at which temperatures the
moisture contained in the material 28 is also evaporated.
It is a basic feature of the present invention to subdivide the
interior of the drum into longitudinally extending passages which
are quite narrow circumferentially so that the material to be
dehydrated is tumbled during drum rotation while confined quite
closely in the path of the gases traversing the particular passage
in which the material is being tumbled. It is to be noted that in
the preferred structure shown each passage is continuous and
distinct from all other passages about the curved heads from one
cylinder to the next. This maintains a much more intimate contact
between the dehydrating gases and the material upon which the gases
are acting and the result is to achieve more quickly the very
effective dehydration of such material. Various baffles which
project from the tubular shells and sleeve and the generally radial
longitudinal partitions serve to distribute the finely divided
material throughout the cross section of the drum in the course of
drum rotation.
The rate of evaporation is fast enough so that notwithstanding the
initial high temperature of the gases, the material is kept cool by
evaporation and never rises high enough to become oxidized.
Accordingly, the dehydrated material discharged will have
substantially natural color notwithstanding that it is sufficiently
dry to keep indefinitely.
* * * * *