U.S. patent number 3,751,824 [Application Number 05/174,966] was granted by the patent office on 1973-08-14 for flow inverter for grain driers.
Invention is credited to Thomas H. Kyle.
United States Patent |
3,751,824 |
Kyle |
August 14, 1973 |
FLOW INVERTER FOR GRAIN DRIERS
Abstract
Flow inverter for use in a gravity flow grain drier of the type
having drying chambers with perforated walls through which drying
air passes. The flow inverter has two flow directing portions for
separating portions of the flow of grain adjacent the air inlet
wall and adjacent the air outlet wall respectively and
simultaneously smoothly deflecting the separated portions laterally
angularly into chutes which direct the portion separated from the
flow adjacent the air inlet wall downstream adjacent the air outlet
wall and direct the portion of the flow adjacent the air outlet
wall downstream adjacent the air inlet wall.
Inventors: |
Kyle; Thomas H. (Blenheim,
Ontario, CA) |
Family
ID: |
22638263 |
Appl.
No.: |
05/174,966 |
Filed: |
August 25, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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835955 |
Jun 24, 1969 |
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Current U.S.
Class: |
34/167;
34/174 |
Current CPC
Class: |
F26B
17/122 (20130101) |
Current International
Class: |
F26B
17/12 (20060101); F26b 017/12 () |
Field of
Search: |
;34/28,29,161,168,169,171-176 ;259/180 ;302/28 ;193/14,29 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sprague; Kenneth W.
Assistant Examiner: Yeung; James C.
Parent Case Text
This invention is a continuation of Ser. No. 835,955, filed June
24, 1969, now abandoned.
Claims
What is claimed is:
1. A flow inverter for use in a grain drier of the type having
spaced vertically extending perforated air inlet and outlet walls
defining a vertical grain drying chamber downwardly through which
the grain flows, said flow inverter comprising
a. first and second pairs of opposed end walls,
b. at least one flow separating vertical wall extending between the
end walls to form a first transverse mouth to be positioned
adjacent one of the air inlet and outlet walls and a second
transverse mouth to be positioned adjacent the other of the air
inlet and outlet walls, said first and second mouths being
coextensive,
c. one end wall of the first pair of end walls extending angularly
downwardly from the first mouth towards the opposed end wall of the
first pair to form first channel means extending downwardly from
said first mouth, for laterally deflecting a portion of the flow of
grain entering said first mouth,
d. second channel means forming a continuation of said first
channel means and directed when positioned towards said other of
the air inlet and outlet walls for directing upstream flow from
adjacent said one of the air inlet and outlet walls to downstream
flow adjacent said other of the air inlet and outlet walls,
e. one end wall of the second pair of end walls opposed to said one
end wall of said first pair extending angularly downwardly from the
second mouth towards the opposed end wall of the second pair to
form third channel means extending downwardly from said second
mouth for laterally deflecting a portion of flow of grain entering
said second mouth, and
f. fourth channel means forming a continuation of said third
channel means and directed when positioned towards said one of the
air inlet and outlet walls for directing upstream flow from
adjacent said other of the air inlet and outlet walls to downstream
flow adjacent said one of the air inlet and outlet walls.
2. A flow inverter according to claim 1 wherein the first and
second mouths are separated by means of a single vertical wall.
3. A flow inverter according to claim 1 wherein baffles are
angularly positioned in said first and second mouths to assist the
flow of grain.
4. A flow inverter according to claim 1 wherein said second and
fourth channel means include smoothly curved chutes.
5. A flow inverter according to claim 1 wherein surfaces transverse
to the direction of air flow through the drier are perforated.
6. A flow inverter in combination with a grain drier comprising
spaced vertically extending perforated air inlet and outlet walls
defining a vertical grain drying chamber downwardly through which
the grain flows, said flow inverter comprising a first flow
separating and concentrating means positioned adjacent the air
inlet wall for separating a first portion of the flow of grain
adjacent the air inlet wall, concentrating it transversely and
downwardly in a path generally parallel to said air inlet wall and
simultaneously smoothly deflecting the separated concentrated flow
portion into a first channel means, said first channel means
operatively joined with said first flow separating and
concentrating portion to direct the separated deflected portion
downstream adjacent the air outlet wall and to permit said first
portion of grain flow to expand adjacent said air outlet wall to
substantially the same transverse dimensions which it had prior to
being separated, and said flow inverter further comprising a second
flow separating and concentrating means coextensive with said first
flow separating and concentrating means and positioned adjacent the
air outlet wall for separating a second portion of the flow of
grain adjacent the air outlet wall, concentrating it transversely
and downwardly in a path generally parallel to said air outlet wall
and simultaneously smoothly deflecting the separated concentrated
flow portion into a second channel means, said second channel means
operatively joined with said second flow separating and
concentrating portion to direct the separated deflected portion
downstream adjacent the air inlet wall and to permit said second
portion of grain flow to expand adjacent said air outlet wall to
substantially the same transverse dimensions which it had prior to
being separated.
7. A device according to claim 6 wherein the grain drying chamber
is elongated transverse to the direction of air flow and a series
of said flow inverter units are positioned side by side along the
transverse length of the chamber.
8. A device according to claim 6 wherein said flow separating and
concentrating means include angularly positioned baffles to assist
the flow therein.
9. A device according to claim 8 wherein said channel means are in
the form of smoothly curved chutes.
10. A device according to claim 8 wherein surfaces normal to the
direction of air flow through the drier are perforated.
11. A flow inverter device in combination with a grain dryer
comprising a vertically extending perforated air inlet wall and a
vertically extending perforated air outlet wall spaced from said
air inlet wall, said walls defining a vertical grain drying chamber
therebetween, said flow inverter comprising
a. a pair of side walls and a pair of end walls having upper edges
defining an upper opening, said side walls being adjacent said air
inlet and outlet walls,
b. at least one flow separating vertical wall extending between the
end walls to divide said opening into a first mouth adjacent the
air inlet wall and a second mouth adjacent the air outlet wall,
c. a first flow deflector extending angularly downwardly from the
upper edge of one of said end walls towards the other end wall to
form first channel means extending downwardly from said first
mouth, said first and second mouths being coextensive,
d. second channel means forming a continuation of said first
channel means and directed towards said air outlet wall for
directing upstream flow from adjacent the air inlet wall, to
downstream flow adjacent the air outlet wall,
e. a second flow deflector extending angularly downwardly from the
upper edge of said other end wall towards said one end wall to form
a third channel means extending downwardly from said second mouth,
and
f. fourth channel means forming a continuation of said third
channel means directed towards said air inlet wall for directing
upstream flow from adjacent the air outlet wall to downstream flow
adjacent the air inlet wall.
12. Method of drying grain comprising the steps of flowing the
grain through a drying zone, passing drying air thorugh the drying
zone transverse to the general direction of flow of grain, said air
entering along a first side wall of said zone and exiting along a
second side wall of said zone, separating a first portion of flow
of said grain adjacent said first side wall, concentrating it
transversely to said general direction of flow in a path
substantially parallel to said first side wall and then deflecting
it transversely to said general direction of flow in a path oblique
to said second side wall, and separating a second portion of flow
of said grain between said first portion of flow of grain and said
second side wall, the transverse dimensions of said first and
second portions of flow being coextensive, concentrating it
transversely to said general direction of flow in a path
substantially parallel to said second side wall and then deflecting
it transversely to said general direction of flow in a path oblique
to said first side wall, said first and second portions of flow
being allowed to expand to substantially the same respective
transverse dimensions which they had prior to said separating and
concentrating steps.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a flow inverter for use in grain driers,
particularly for gravity type grain driers having drying chambers
with perforated walls.
2. Description of the Prior Art
The need to accelerate the rate of drying grain has led to the
development of specialized grain drying equipment. One form of
grain drying device that has received wide acceptance is a gravity
flow drying chamber. The basic components of this device are
perforated walls between which the grain to be dried is deposited,
means to heat air and means to force the heated air into the
chamber through one of the walls, through the grain between the
walls and out through the other wall. The grain continuously moves
down through the chamber and the rate of flow of the grain is
controlled by means of a metering device in the bottom of the
chamber. While devices of this type currently on the market
represent a great advancement over the natural drying processes
previously employed, they are far from being perfect.
Wet grain is a very difficult material to handle, being of a soft
and soggy nature, and it tends to solidify under the pressure of
the overlying mass when deposited in a drying chamber. In this
condition, the fluid properties of the grain are extremely
irregular. A major problem in drying chambers results from the fact
that as grain dries its fluid properties increase over those of wet
grain. Thus, the warm dry air entering one wall of the chamber
picks up moisture from the grain adjacent that wall and as this air
moves across the chamber through the grain, it becomes cooler and
more moisture laden so that its ability to dry the grain decreases
as it progresses across the chamber. The result of this is that a
drying front moves slowly across the bin.
Because of this slowly moving drying front, all of the grain in the
drying chamber is dried only after a very long residence time. This
can be aided somewhat by increasing the temperature and flow rate
of air but this requires the use of large quantities of fuel and,
moreover, by the time the grain adjacent the air exit wall becomes
dry, the grain adjacent the air inlet wall may be overdry,
resulting in economic weight loss or even scorching or charring
beyond the point of utility.
Various attempts have been made in the prior art to overcome the
problems of the flow characteristics of the drying grain including
baffles to break up the flow. However, once grain has begun to flow
it develops momentum tending to keep it moving. The result is that
flow channels appear behind the drying front while the wetter grain
ahead of the front tends to remain still. Thus, the relatively dry
grain tends to merely flow over these baffles in flow channels
without properly mixing with the grain which is still wet.
SUMMARY OF THE INVENTION
I have now been able to overcome these difficulties by inserting
flow inverters into the drying chambers of gravity flow grain
driers.
My flow inverter comprises a housing unit which is adapted to be
fitted within a grain drying chamber and conforms to the inner
surfaces thereof. The housing comprises a first flow directing
portion for separating a portion of the flow of grain adjacent the
air inlet wall and simultaneously smoothly deflecting the separated
portion laterally angularly into a first channel means. This first
channel means is operatively joined with the first flow directing
portion to direct the separated and deflected portion of grain into
the conduit downstream adjacent the air outlet wall. The housing
further comprises a second flow directing portion for separating a
portion of the flow adjacent the air outlet wall and simultaneously
smoothly deflecting this separated portion laterally angularly into
a second channel means. This second channel means is operatively
joined with the second flow directing portion to direct the
separated deflected portion into the conduit downstream adjacent
the air inlet wall.
My flow inverter has the great advantage of being able to
positively divide the flow through the drying chamber in the region
of the drying front so that the relatively wet grain ahead of the
drying front is moved into direct contact with the hot dry air
entering through the air inlet wall while the already dry grain
behind the front is moved into the area of the air outlet wall. The
grain moved adjacent the air outlet wall, because it is already
dry, is in a free flowing state so that the air passing through
which has picked up moisture from the wet grain will flow through
the dry grain with relative ease without again saturating this
grain with moisture. The result is that the grain emerging from the
bottom of the grain drying chamber is of a relatively uniform
dryness.
Since most commercial driers contain an elongated drying chamber, a
series of the inverters are normally placed side by side along the
length of the column. For instance, in a chamber one foot wide and
eight feet long, eight one foot square inverters may be
inserted.
The two flow directing portions can be equal in size so that the
flow of grain in the drying chamber can be divided in half. This
has the particular advantage of simplifying construction.
However, it is also possible to have the flow directing portions of
unequal size so that more of the flow of grain is directed in one
direction than the other. This can be varied depending on the
position of the inverter in the drying chamber. Usually the
inverter is positioned in the chamber approximately two thirds of
the way down from the top.
According to yet another embodiment of my invention, the flow can
be divided into two portions adjacent the air inlet and outlet
walls respectively, as well as a third portion between these which
is not diverted but allowed to continue straight down the center of
the chamber. With this arrangement the driest grain adjacent the
air inlet wall is diverted adjacent the air outlet wall, the
wettest grain adjacent the air outlet wall is diverted adjacent the
air inlet wall and the central portion of the grain which is of
intermediate dryness continues down the center of the drying
chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
Certain preferred embodiments of my invention are illustrated by
the attached drawings in which:
FIG. 1 is a perspective view of a grain drying device of the type
in which the flow inverter of this invention is employed;
FIG. 2 represents diagrammatically, a cross-section of the drying
device of FIG. 1 and shows the location of the flow inverter of
this invention relative to the drying device as a whole;
FIG. 3 is a perspective view of my new flow inverter;
FIG. 4 is an end elevation of the flow inverter shown in FIG.
3;
FIG. 5 is a side elevation of the flow inverter of FIG. 3 and
FIG. 6 is a sectional view along line 6--6 in FIG. 3.
With reference to FIGS. 1 and 2, the numeral 10 indicates a support
frame of a grain drying device. Extending upwardly from the frame
10 are end walls 11 and side walls 12, the side walls being
perforated to permit passage of air therethrough.
As can be seen from FIG. 2, the dryer has an internal plenum
chamber A formed from perforated side walls 15, flow dividing top
16 and bottom 17. Two vertical drying chambers B and C are defined
by walls 12', 15' and 12,15 respectively. By means which is not
shown and is not a part of the present invention, heated air is
forced into the plenum chamber A. From chamber A this air flows
through walls 15 and 15' into drying chambers B and C, through the
grain contained therein and out through walls 12 and 12'.
The grain to be dried is fed into the dryer by known means through
opening 13 and flows over plenum chamber top 16 into drying
chambers B and C. The grain is supported in thee chambers by
baffles 18 and continuously passes out of the bottom of the
chambers at a controlled rate by means of metering devices 19 and
into auger 20. The auger 20 delivers the grain into elevator
housing 14.
Referring now to FIGS. 3 to 6, it will be seen that each flow
inverter unit is divided into two parts 25a and 25b by means of
vertical flow dividing wall 26. A pair of vertical end walls 27a
and 27b are joined to wall 26 and a pair of vertical side walls 28a
and 28b are joined to end walls 27a and 27b.
Inwardly inclined end panels 29a and 29b positioned between walls
28a and 26 and between walls 28b and 26 respectively, form the
bottoms of flow deflecting portions.
These flow deflecting portions merge into grain carrying chutes 40a
and 40b. The chutes are composed of smoothly curved bottom walls
30a and 30b, inner side panels 31a and 31b, inclined top panels 33a
and 33b and extensions of end walls 27a and 27b. Bottom walls 30a
and 30b smoothly merge into vertical side walls 28a and 28b
respectively, while top panels 33a and 33b angularly join dividing
wall 26. End walls 27a and 27b serve as end walls for both the flow
deflecting portions and the chutes. The inner side panels 31a and
31b are angularly joined to inwardly inclined end panels 29a and
29b respectively.
Preferably these inner side panels 31a and 31b do not extend beyond
chute bottom walls 30b and 30a respectively. This can be clearly
seen from FIG. 3 where panel 31b does not appear beyond the bottom
30a of chute 40a. The purpose of this is to allow the grain to flow
off the side as it emerges from the chute 40b and into the space
behind chute 40a.
In order to cut down on bridging, particularly of the wet grain, on
the inclined surfaces 29a and 29b, additional inclined baffles 32a
and 32b can be inserted.
The inverter can be fabricated as an integral unit with a single
dividing wall 26 or each half 25a and 25b can be fabricated
separately with its own wall 26. These two halves are then simply
joined together so that wall 26 becomes a double wall.
My inverter can be fabricated from many different sheet materials,
e.g. sheet metal. Preferably the panels normal to the direction of
air flow have perforations 35 so that the air can flow through and
drying will continue without interruption during the flow
inversion.
While the embodiment described above represents the simplest and
least expensive embodiment of my flow inverter, it will be
appreciated that various other physical embodiments are possible.
Thus, for instance, the side of the inverter receiving dry grain
can have a pair of chutes carrying the grain to the air outlet side
while the side receiving wet grain can have a single large chute
which passes between the two small chutes for dry grain.
* * * * *