Note: Descriptions are shown in the official language in which they were submitted.
Case 3659
I
1 MULTIORE~ATIO~AL TREATMENT APPARA~U~
A~D M~THOD FOR DRYING A~ THE ~IKE
D~SCRIPTIo~
s
BACKGROUN~ AND DESCRIPT~O~ OF THE INv~lION
! 7 ~he present inve~tion generally r~lates to an
apparatus and mathod for drying or othorwise traating
9 materials that are conveyed through an enclosed treating
environment. ~ora particularly, the invention relates to
11 an especially versatile apparatu~ and method that allow
the operator to select among a variety of operational
13 mod~. Trea~d ~ses, such as heated air and the li~e,
ar~ able to be circulated through a vari~ty of paths and
15 combinations of movement that are d~signed to prss~nt
different types o treatments and conditions to the
17 mater~al being treated. Included is a~ assembly tha~
convsy~ a foraminous belt, and the traated gas pat~ can
19 b2 selected including downwardly through materials on the
belt, upwardly therethrough and by an arrangemen~ in
21 which the mat~rials being treat~d are su~jacted ~o
~luidized b~d conveyed condition~ undar which particulate
23 mat~rial~ are generally tumblea along the foraminous
con~eyed b~lt. By virtue o~ thi~ invention, a single
25 pi~ce of eguipment can b~ easily adiusted so a~ to carry
out a number of different treatment procedure~ that are
-- 2
1 needed for processing or treating a variety of different
products, such as different dry cereal products.
3 Dryers, ovens, refrigeration units, and the like have
been provided which circulate treated gases such as
5 heated, p~essurize~ air for intimate, treated con~act
with a variety of different products, including food
7 products, as well as granulated or particulate materials,
such as dry cereals, as well as numerous other non-edible
9 and edible items. Typically, these devices are designed
to perform primarily a single functiQn, such as baking
11 pi~æas, making crackers, baking coo~ies, drying
chemicals, or c~rrying out a particular stage in th~
13 manufacture of a particular type of dry cereal.
With particular reference to thQ dry cereal
15 processing industry, cereal products o~ jdirferent ~ypes
require di~ferent processing or treating steps. Most dry
17 cereal products require multiple treatment steps, each
necessitating a type of drying or treating apparatus that
19 may not be suitabl~ for any other type of treatment or
processing step. For e~ample, at certain stages, some
21 ary cereal product pr~pa.rations call for a~ apparatus
that will permit alternating upflow and down~low o~ dry
23 air through the c~real preparation as it is bcing
conv~yed thro~gh th~ apparatus. Such an approach may be
25 needed, for ~ample, for co~tinuous cooked flake pro~uct~
that need to remain substantially stationary on the
27 movi~g conveyor bed. Sometime~ it is important to
minimize movement of tha cer~al particulat~ while ~hey
2g are on the conveyed surface in ord~r to achieve ~lavor
and vitamin retention.
I 31 Other dry cereal prsduct~ may re~uirG a puf-toasting
or a blis~er-to~sting procedur~ that ca~ be carried ou~
33 under relatively severe conditions in ord~r to impart a
particular property sl~ch as color and/or flaYor
3 --
1 development to the ultimately produced dry cereal
product. Some cereal products are best prepared by
3 including treatment with a so-called fluidized bed
apparatus which typicall:y includes a solid conveyor and
S relies upon pressurized l3as impingement onto the t~p
SUrfaGe of this solid conveyor in order to tumble or turn
7 individual particles to thereby affect sp~cial treatments
or to provid~ especially eficie~t tr~atment procedllres.
9 For e~ample, grain grits can be subjected to special
treatments to form same ~irst into cup-shaped, thin
11 flakes and then puff-toast them into thicker and larger
flakes or to blister-toast them into blistered and
13 wri~kled flakes under high temparature, short time
; fluidized bed conditions. Without this type of
: 15 treatment, materials, such as grain grits, would form
unsatisfactory flakes that look similar to ish scales.
17 Cer~ain other cer~al produ~ts cannot hs suitably
processed with this fluidized b~d impingement type of
19 equipment because the rather violent impingement activity
will damage the granules. An e~ampla of a cereal o this
21 type is one having a coating, ~ch as a suga- coating,
which will bs removed from the product by frictional
23 engagement with the pressurii~ed air jets and with the
solid con~eyor surfacs upon which the air jsts impin~a.
2~ Other equipment is ot~n nseded to accomplish other
procedur~ ha~ing their ow~ respective tim~, temperatur2
27 and prcduct mo~emen~ condition~ and rsguiraments.
E~ampl~s of equipm~nt used herstofore in the cereal
29 i~ustry, as well as in other industrie~, in order to
p~rform certain type~ of drying or other proc~ssing
31 oparatio~s include the impingeme~t type of system~ such
as those illustrated by U.S. patents No. 3,060,590 and
33 No. 3,X29,377, as well as by No. 3,262,217 which also
include~ the p~ovision of a vibra~ing conveyor onto which
7at
~,
1 impingement takes place. While thes~ types of devices
which basically operate on air impingement principles can
3 be useful for certain types of applications, they do not
provide the kind of versatility that can reduce th~
5 capital outlay and floor space needed or processin~ a
variety of different products such as a full line of dry
7 cersal product~. Other devices that are useful, but are
of limited versatility, include those of the traveling
9 screen type in which the products being processed are
spread on a screen which is conveyed through a heated or
ll otherwise conditioned environment. Thi~ type of an
apparatus will not allow for the formation and use of a
13 ~luidized bed, and it is not particularly suitabl~ for
performing puffing or toasting operations or other
lS procedures.
It has been found that, by proceeding in accordance
17 with the present invention, it i~ po~sible to provide
numerous types of treatment functions within a single
l9 piece of ~quipment. The equipment can proceed to provide
operating condition~ of the typ~ povided by a traveling
21 screen drying apparatu~, while permitt ng adjustments in
conditions to transfor~ samQ into an apparatus that
23 provide~ a fluidized bed to levitate and tumble the
materi31~ while su~jecting them to desired time, flow and
25 ~emperature conditions.
In summary, the present inve~tion is an apparatus and
27 method that incorpo~ates a foraminsus conveyor surface
which can, whe~ desired, be tran~form~d into a
29 fluidization surface that operates in the ~aturs o~ a
device that incorporates impingement of ga~ jets onto an
31 imperforate surface along which th0 material~ bei~g
treated are conveyed. In addition, means are provided
33 for se:lectively varying the circulation path and movement
velocity of th~ gaseous treatment fluid. Includ~d in the
'7~-~7'~
l means for varying the treatment procedures accomplished
by the present invention is the use of a lower plenum
3 beneath a foraminous conveyor belt, coupled with means
for varying pressure e~erted by the fluid within the
5 lower plenum onto the foraminous conveyor.
It is a general object of the present invention to
7 provide an improved apparatus and method for imparting
treating fluid to materials passed through a treatment
9 zone.
Another object of th.is invention is to provide an
ll improved drying and treating apparatus and m~thod that
embody multioperational features within a single unit.
13 Another object of the present invention is to provids
an improved apparatus and method for performing a variety
15 of different drying or other treatment operations by
modifying parameters of the treatment fluid.
17 Another object of this invention is to provide an
improved apparatus and method ~or multioperational
l9 drying, toasting, or otherwise treating cereal materials
with supplies of f lowing gas.
21 Another object of this invention is to proYide an
impro~ed apparatus and method wherein ~luidized bed
23 conditions can be provided without re~uiring an
im~erforate impingement suxface.
These and o~her objects, feature~ and advantages of
the present invention will be clearly understood tArough
27 a consideration of the following detailed description.
~9 BRI~F D~TRTION OF THE DRAWING~
In ths course of this descriptisn, reference will be
31 made to the attached drawings, wher~in:
Figur~ l is a side elevational view o an apparatus
33 according to this invention,
- 6 ~ (3~t7~
.
1 Figure 2 is a generally schematic illustratio~ of an
embodiment of th~ invention which shows the fluidizing
3 gas circulation according to the present invention;
Figure 3 is a generally schematic illustration of an
5 embodiment of the invention which shows the down~low gas
circulation through the bed according to the present
7 invention;
Figure 4 is a generally schematic illustration of an
9 embodiment o~ the invention which shows the upflow gas
circulation through the bed ~ccording to the present
11 invention;
Figure 5 is a more detailed ~lRvational Vi8W,
13 partially cut away! of a portion o the apparatus
illustrated in Figure l;
Figure 6 is a transverse cross-s~ctional view
generally through th~ em~odiment sho~n in Figure 5;
17 Figure 7 is a detail view of a portion of the
preferred foraminous belt included in accordance with the
19 present invention,
Figur~ 8 is a partial transv2rs~ cross-sectional view
21 illustrating an optional feature;
Figure 9 is a partial transv~rse cross-sectional view
23 illustrating an al~ernativ~ em~odiment: a~d
Figura lO is a partial longitudinal c~oss~sectional
25 view illustrating a further po~sible embodiment.
27 D~RTPTION OF THE PARTICU~AR EM~ODl~h~S
A multioperational drying or cooking apparatus i5
29 illustrated in Figure 1. A plurality of enclosu~a
as~e~blie3, genarally designated a~ 21, ar~ æhow~
31 conveyor assembly, generally de~ignate~ as 22, is shown
as a continuous unit that join~ the enclosure
33 assemblie~ 21. As illustrat0d, each enclo~ure assembly
includes two separately controllable tre2t.nan~ zones. In
35 some applications, but a single enclosur~ assembly may be
~37~
-- 7 --
1 provided with greater numbers o~ treatment ~ones. In
other versions, each enclosure assembly could have its
3 own separate conveyor assembly, and other processing
steps could be carried out therebetween. Another option
5 which is avaIlable when using a co-,v~or ~ssembly, such
as the preferred fle~ible conveyor assembly, is to have
7 the conveyor assembly continue onto a diferent treating
station or stations positioned between th~ enclosure
9 assemblies 21.
Each enclosure assembly 21 includes gas conditioning
11 means, such as a burner assembly 23. Means are also
provided, as discussed in greater detail herein, for
13 pressurizing the conditioning gas, for directing same,
and for circulating same through a variety a diferent
15 paths and path combinations, depending upon th~
particular treating, drying or baking function and the
17 like to be performed within th~ enclosure assembly 21.
Controls including gauges 24 and air saal dampers 25 are
19 g~nerally illustrated. Circulatin~ fan assemblies 26 are
also generally shown in Figur~ 1.
21 Conveyor assembly 22 includes an endless foraminous
conveyor belt 27 mounted along pulley assemblies in a
23 generally known manner. Included are a driv~ pulley
assembly and a driven pulley assembly ag, as well as
25 other takeu~ pullays and the like, th~ details of which
will be ~ppre~iated ~y one of skill in tha art. The
27 p~ef2rred structure of the ~oraminou~ conveyor belt 27 is
illustrated in Figure ~. It can be characterizQd as
29 woven mstal wir~ that is capa~le of a~ e~trem31y full
ran~e of movement in the dire~tion o~ traYel. Such
31 movemsnt capabilities include being able to readily
follow inclined paths to move ~rom equipment of dif~ering
33 treatment heights and being able to wind arQund conveyor
pulleys and drive pulleys of r~la~iv~ly small diameter.
-- 8
I
1 The illustrated foraminous conveyor belt 27 includes
a plurality of generally parallel rods 31 which are
3 generally threaded through so as to join alternating and
generally mating accordian or ~ig-zag fli~hts 32. The
5 rods 31 join the ~lights 32 by pivotally connecting
forward bends 33 of one flight 32 in alternating fashion
7 with rearward bends 34 of an adjacent flight 32.
Preferably, the rods 31 and ~he flights 32 are made o~
9 stainless steel or other durable and rigid material that
is able to withstand thl~ temperatures applied on the unit
11 and is safe for use with food products.
Figure 2 illustrate~i the operation of the present
13 invention in a manner in which ~luidized bed conditions
are presented above the foraminou~ belt 27 o the
15 conveyor assembly. The circulating ~an assembly 26
provides a supply of pressurized ga~, such a~ air, which
17 may, for example, be heated by means of the burner
assembly 23. Whil~ the illustrated apparatus
19 recirculates th~ treating gas, make-up gas or air can be
added as needed at 35 in order to vary or maintain ga~
21 temperature, drying characteristics and the like. The
pre~surized ga~ is passed through suitabl~ conduits or
~3 passa~e into an upper plenum 3S and a lower plenum 37.
When desir~d, sid~ strsams of ga~ ~rom th~ circulating
25 fan as~embly 2~ can b~ provided. The sid~ stream flow is
typically moni~ored by dampers or valves 38t and the
27 gasaou~ ~low ~its onto the longitudinal ~dge~ of the
foraminou~ belt 27 through suitabls elongated lots 39 or
29 th~ like. This longitudinal side stream arrangement
tassist~ in maintaining the materials being tr~ated on th~
31 foraminou~ belt 27, whila also as3i~ing in maintaining
the fluidi2ed condition provided by thi~ moda o~
33 operation of ths invention.
- 9
1 With more particular reference to the fluidization
tha~ is achieve~ by ~his mode of operation, the
3 circulating fan assembly 26 and/or a damper or valve 41
upstream of the upper plenum 36 permit adjustment of the
5 pressurization of the gas, such as air, w~thin the upper
plenum 36, which is preferably closely monitored. This
7 pressurized source is then directed downwardly by
suitable directing devices, such as the illustrated
9 plurality of tubes 92. Passage of this pressurized air
through such directing devices will, of course, increase
11 the velocity of the gas flowing therethrough. This
velocity can be adjusted by any suitable means, such as
13 the known means of providing a sliding or movable hole
plat~ 43 so that holes therein are moved into or out of
15 alignment with outlets of the directing tubes 42 or the
like. Differsnt positioning in this regard is
17 illustrated ln Figures 2, 3 and 4. The result of the
various adjustment featuxes iq that output rom the
19 directing davices 42 is variable and i~ ori~nted
generally downwardly toward the foraminous conveyor 27.
~1 The pressurized gas antering the lower plenum 37
builds a desired prsssur~ o~ gas within the lower
23 plenum 37. This prassure can ba provided, maistained
and~or monitored by a damper or valve 44, th~ circulating
25 fan a~sembly 26, and ths like. If necessary, a damper or
valve 45 could be opened to adjust the pressure within
27 he lower plenum 37; although this damper 45 will
typically be closed during this mode of operation. In
29 acc~rdance with generally known principles, one or more
perforat d distribution plates 46 can be provided in
31 ordar to further direct ga~ flow or control pressure
within ~he lower plenum 37.
33 According to the mode illustrated in Figure 2, the
primary path out of the lower plenum 37 i9 through the
35 foraminous conveyor belt 27, th~ plenum being
-- 10 --
1 substantially closed on all sides e~cept for its upper
portion that directly underlies the forami~ous conveyor
3 balt 27. ~y this arrangement, the generally downwardly-
directed gaseous flow from the upper plenum 36 impinges
5 upon a pressurized gas layer that is provided at the
boundary where the downflow gas meets the upflow gas.
7 This boundary may be considPred to be a generally
horizontal cuxtain provided at or just slightly above the
9 foraminous conveyor belt 27 which is generally provided
by the pressurized gas of the lower plenum 37.
11 Typically, the fluidized bed conditions of this inventio~
are achieved when the upward flow from the lower plenum
13 is between about 30 percent and about 80 percent of the
downward flow from the directing devices.
Particulate materials 47, which ca~ be cereal flakes,
nuggets, granules, puf~s or the lika, generally tumble
17 along the ~oraminous conveyor ~elt 27, but they do not
pass therethrouyh to any si~nificant dogree. This
19 action, which is generally illustrated by curved,
- arrow-headed lines in Fi~ure 2, generally levitates,
21 rolls, tumbles or fluidizes the particulat~ materials 47
alonq, with and ge~erally abov~ th~ foraminous conveyor
23 belt ~7. Also, gen~rally in accordance with impingement
ty~e~ of dr~ing or treating devices, the pres~urized air
25 that luidize~ the particulate materials 47 simultan-
eously impinges upon these materials a~ they are tumbled,
27 turned and moved, with tha result that treatment of the
particulate materials 47 with this treating gas is
29 enhance~.
Thc trea~ing gas then flows out of th~ enclosuro
31 assembly 21 in a manner that i~ generally appreciated ;n
the art, typically by way of an outlet as~embly including
33 a damper or valv~ 48 ~or traasmission to a cyclone
assembly 49 or ths like for removing undesirable
35 materials ~rom, or otherwise treating, the gaseous medium
3~
1 recirculating through the apparal:us. Certain such
gaseous medium can e~it the cyclone apparatus by a
3 typical e~haust arrangement 51, which can be useful to
maintain temperature and drying characteristics, all in
5 accordance with generally known principl~s.
By the mode or arrans~ement illustrated in Figure 2,
7 the particulate material~i 47 are subjected to fluidized
bed conditions in the nat:ure of those developed by dryer
9 or treatment devices utilizing impingement principles in
which a downwardly direct:ed flow of pre~surized gas
11 impinges upo~ an imperfor.ate and rigid surface. This is
accomplished even though no such imperforate impingement
13 surface is provided. Typical co~dition~ that are needed
in this regard for dry cereal proce~sing include
15 relatively high temp~ratures, on the order of about 400
to 550F. and somewhat brief treatment time~, on the
17 order of about 30 to about 90 seconds, while air
velocities out o~ the directing dsvices will be in the
19 range of appro~imately 8000 to appro~imately 12,000 ~eet
per minute. Moisture level~ can be reduced ~rom a range
~1 on the ~eneral order of 15 to 20 percent down to abou~
~ percent.
23 With reference to Figure 3, the particulate
materi31~ 47 are subje ted to a downward flow
25 therathrough o treatment ga3 from the upper plenum 36
whil~ these mat~rials 47 are g~nerally po~ition~d on the
27 oram~nous co~veyor belt 27. Damper or valve 48 is
substantially closed, and the b~lk of the volume o
29 treatme~t ga~ then enters the lower plenum 37, which is
at a lower pressure than that of tha uppar plenum 360
31 The flow is t~en passed out of the lower pl~num 37 and is
circulated to the cyclone asse~bly 49 by opening the
33 damper or valve 45.
Drying, cooking or treating operation~ of the type
35 that can be carri2d out on a so-~alled traveling screen
assembly can suitably be accomplished accordin~ to this
~3~
.
- 12 -
1 mode of operation~ For e~ample, dry cereal flakes such
as bran flakes ara typically dried or treated with an
3 upflow through the bed of flakes (which could be carried
out by the pr~sent invention when in the mod~ illustrated
5 in Figure 9), and they are then subjected to downflow
drying conditions that arle typically more efficient th~n
7 up1Ow drying An e~ample of a typical downflow drying
operation would use air at between 250 and 300F., air
9 flows of on the order of about 200 to 300 ~eet per
minute, and retention times o~ on tho ordsr of a few
11 minutes. A typical flaked product will then be dried to
a moisture lavel of about 2 to 3 percent.
13 The operational mode or Figure 4 is one in which
there is an upflow of treatment gas through the bed of
15 particulate materials 47. Treatment~ requiring upflow o
gas through particulate material can b~ practiced when
17 the invention i8 adjust~d according to this mode. Damper
or valve 45 is substantially closed, and tha prassurized
l9 air flowing through the damper or valve 44 prsssuri~es
the lower plenum 37. With this arran~ement, treatment
21 gases pas~ upwardly through the foraminous or woven m~tal
conveyor 27 in order to thereby txeat particulate
23 material 47 ther~on, after which flow continue~ throu~h
damp~r or valve 48 for retur~ to th~ cyclone 49 and
25 typically th~ damper or valve 41 i~ closed. With
refarence to dry cereal proce~sing, this upflow mode, for
27 esampl~, can b~ used to provide initial surfac~ drying of
1ake3 in order to pr~vent both sticking to the conve~or
29 belt and matting of the flakes, which initially can have
a moisture cont~nt in the approsimate ~0% range.
31 Further details of an apparatu~ ~tructure ~uitable
for proceeding in accordanca ~ith thi~ inv~ntion are
33 illustrat~d in Figuras 5, 6 and 7. A plurality of the
tubular directing devices 4~ are shown, each with a
35 tapering ~ip having a reduced inner diameter. Such
- 13 ~
l directing devices 42 typically run su~stantially the
entire length of each treatment zone within the enclosure
3 assembly 21. Details of the preferred woven metal
endless belt 27 as discussed herein are also shown.
With reference to Figure 8, this ilIustrates a
situation which could be practicsd if it would be desired
7 to convert the present apparatus to one more closely
resembliny a classical type of impingement structure. A
9 substantially flat, elongated and imperforate plate 52
can be positioned substa:ntially directly beneath the
ll foraminous endless belt 27 at those location~ at which
the belt 27 is in its pathway under the tubular directing
13 devices 42. By this option, the perforated endless belt
is substantially transformed, from an operational point
15 o view, into an imperforate moving sur~ace.
Concerning Fi~urs 9, the directing devices of this
17 embodiment taka the form o a plurality o~ constrict~d
openings 42a on thc bottom side of an upper plenum 36a.
l9 Treatment gas enters the plenum 36a when the damper or
valve 41 is opened. Flow into th~ lowax plenum 37 passes
21 through damper or valve 44. Esit from above the
foraminous belt 27 occurs wh~n damper or valve 48 is
23 opened, and e~it from the lower plenum 37 i~ through the
damper or valve 45.
Rsgarding the embodiment which is illustrated in
Figure lO, an upper plenum 36b is illustrated. A
27 plurality of directinq dsvic~ 42b ars positioned along
the bottom surface of the plenum 36b. The~ directing
29 de~ic~ 42b taka the form of elon~ated transversa slots
which dir~ct treatment gasas gensrally downw~rdly onto
31 the foraminous conYeyor belt ~7 when tha downward mode or
tha flui~i~ation mode of this embodiment i~ pr~cticed.
33 While ganeral re~erence herain ha~ baen made to dry
ceraal processing procedures, and especially with respect
35 to conclitions that ar~ met ~or esisting dry cereal
3'7~'7~
- 14 -
l manufacturing, it should be borne in mind that the
versatility afforded by the present inYention i5 of
3 greater scope than this. For e~ample, because of the
ease of use and cost-effective operational capabilities
S of this invention, novel operations are contemplated.
One possibility is singlls sided coating of dry cereal
7 types of products or dry cereal processing that embodies
a combination of toasting, then coating and then drying
9 operations in a single piece of equipment.
It will be understood that the embodiments of the
11 present invention which have been described are
illustrative of some of the applications af the
13 principles of the present invention. Numerous
I modidifications may be made by those skilled in the art
15 without departing from the true spirit and scope of the
invention.
