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Патент USA US2134229

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Oct. 25, 1938.
Filed Oct. 20, 1934
66255671, 2/. L 1%)56011'06,
[via MW
‘ Patented Oct. v25, 1938‘
' Gaston J. Lipscomb, Montclair, N. J.
Application October 20, 1934, Serial No. 749,258
‘1 Claim. (Cl. 34-7-23)
The present invention relates to the apparatus drying tiers 20 similar to those of my copending
for drying vegetable ?ber such as bagasse, and application, each tier comprising alternate re
aims generally to improve existing methods and ticulated sections 2| and open spaces 22, the
apparatus for that purpose.
‘ ’
reticulated sections of each tier being imme
More particularly, the present invention aims diately below an open space in the tier above it 5
to improve the method and apparatus for dry
so that as the bagasse is brushed off the section 2|
ing vegetable ?ber as is disclosed in my copend
of one tier‘ by a rotating rabble arm 23, it will
ing application Serial No. 738,112, ?led August be brushed into an adjacent opening 22 and fall
2, 1934, by providing a new method and appara
directly upon a reticulated support 22 below.
tus which will substantially dry bagasse to a dry
The number and size of the tiers, as well as the
ness of approximately 7% in a minimum of time‘
and under materially reduced ?re hazards.
One of the principal aims and objects of the
invention is to provide an improved method and
‘apparatus for drying ,bagasse which will give
‘good e?iciency, highly satisfactory drying as well
as reduce the ?re risk to 'a minimum.
The salient features of the method and the
construction of the apparatus are best illustrated
20 by reference to the accompanying drawing illus
trating in diagram a suitable'apparatus for carry
ing outthe method.
In the drawing—
Fig. 1 is a section elevation of my improved
25 apparatus for carrying out the method; and
Fig. 2 is an enlarged detail view of the feed
ing and regulating means of the drier.
number of rabble arms for each tier will, of
course, vary according to the capacity of the
plant and the degree of dryness to be desired.v
According to the present invention, the drying
is effected by moving the wet bagasse for a sub- 15
stantial distance in a current of very hot air or
?ue gas, preferably at a temperature of about
800° to 1000° F. to extract a substantial amount‘
of moisture from the material and then completing the drying of the bagasse-by moving it in 20
a counter-current of hot air at a temperature of -
‘between 250°. and 400° F.
The hot ?ue gases and heated air may be sup
plied from a suitable source, as for example, a
Dutch oven 25 having a cook's furnace 26 adapted
to burn a.quantity of bagasse‘ which advantage
ously may be a percentage of the bagasse dried‘
The cook's furnace of the oven 25
may be supplied with a forced draft-in the usual
manner anda secondary combustion chamber 21 30
as is usual. The products of combustion of the
furnace are advantageously divided and may be
As in the case of my prior application Serial _ in the drier.
No. ‘738,112, above referred to, the wet bagasse
30 containing from 45% to 50% .of moisture, is de
livered to a drier casing through which hot air is
circulated, the bagasse being fed to successive
tiers during its progress through the drier casing.
_ According to the present invention, the wet
bagasse is delivered to a feeding box, I 0, which
may be a circular sheet mounted above the drier
casing I3. Rotatably mounted with the feeding
box It is a vertical shaft I4 carrying a feeding
cone l5 upon which the bagasse is delivered from
40 a plurality of feed spouts It on either side of'v
the feed cone so as to more uniformly distribute
the bagasse upon the rotating'feed cone. The
feed cone may carry a plurality of radially dis
posed rabble arms " for spreading the bagasse
.45 into the openings of a stationary distributing
plate l8. ' Mounted immediately below and close
variably controlled as by damper 21*, a major
portion of the gas being passed through ?ue 28 to an annular air inlet 29 surrounding the feed
box I II and directed inwardly-to the'interior of
the feed box, by means of radial openings or
nozzles ‘20 so that?‘ the applicatiomof the hot flue
gases to the wet bagasse will be as uniform as '
possible circumferentially of the drier.
The balance-of the products’ of combustion 3g;
from the Dutch oven are passed through'a “heat
exchanger 3] which may advantageously ‘be of
any‘ suitable design by means of which air,
culated by fanJ-2 may be heated to a suitable 45
degree, the flow of.?ue gases through theflieat
ly adjacent to the plate l8-is an adjustable plate exchanger II,» and hence the temperature of air ,
I! having ‘openings corresponding to the open
heated thereby, being controlled by valve, 33..
ings in. the distributing plate, the plate I! being ‘The air heated by thegheat exchanger" passes
adjustable around the shaft I! so that it may-be through conduit 34 to an annular hot- air inlet‘ 5o
adjusted with reference to the plate It and thus 35 surroundingthe drier casing 12 at its lower»
vary the size, of the openings in. the distributing end, the hot air being admitted to the interior
plate I l to variably control the feeding of bagasse of‘ the casing II by means of
openings or
into the drier.
nozzles 36 so that the appllcationof heated air
Below the distributing plate I. is a plurality of tothebagasewlllbeuniformcircumferentiauyu'
of the drier. Obviously the temperature of the
hot ?ue gases entering the feed box III may be
variably controlled by suitable means, as for ex
ample, a damper regulating the admission of air
to the secondary combustion chamber 21 of the
oven 26.
A fan- 38 is preferably provided to draw off the
dust and moisture laden air and gases from
the drier casing and preferably this fan is con
nected to the casing intermediate the ?ue gas
inlet at the upper end of the drier and the hot
air inlet 35 and the lower end of the drier.
Preferably the exhaust fan 38 is connected to the
drier by means of an annular outlet or exhaust
The shaft I 4 advantageously extends longi
tudinally of the full height of the drier and may
be advantageously driven by suitable speed reduc
tion gearing 48 at the upper end.
Advantages of my present invention over the
method and apparatus disclosed in my copend
ing application Serial No. 738,112 are that a
more complete dryingv of the bagasse may be
effected in a shorter time and hence the capacity
of the drier may be increased without serious 10
liability to ?res occuring in the drier. By ?rst
subjecting the wet bagasse to the hot ?ue gases
which may be as hot as 800° to 1000° F. to par
tially dry them, and ~then ?nally drying the ba
gasse in a current of air at from 250° to 400° F., 15
15 chamber 39, and the fan advantageously delivers
the dust laden air and ‘gases to a suitable dust ' I am able to dry bagasse to a high degree of
collector which may be of the cyclone type. The dryness (with a moisture content as low as ‘7%)
fan 38 is of sufficient capacity as to produce a in a relatively shorter time than was possible
with the method disclosed .in my copending ap
negative pressure with the casing I3.
It is important that the drying take place plication. For example, the drying may be com 20
within an enclosed chamber and in the absence pleted according to the present invention, in 15
of air, except the hot air and gases which are
circulated through the drier, and hence it is ad
vantageous to provide an air lock both at the
feeding and discharge end of the. drier. - This
may be satisfactorily accomplished by means of
the star wheel mechanism disclosed in my co
pending application, but in connection with the
discharge I ?nd the more satisfactory air lock is
30 obtained according to the present invention.
_ Accordingly, the lower end of the casing l3
may comprise downwardly and inwardly inclined
walls-forming a discharge cone 4|, the cone ter
minating at its lower end in a horizontal tube 42.
The lower end of the shaft may be, provided with
a stirrer or scraper 43 to prevent bridging of the
dried bagasse in the cone, and to permit a nor
mal ?ow of dried material to the tube 42. A
plunger 44 reciprocated by any suitable means,
minutes, and preferably the exhaust or discharge
outlet 39 is- so located that bagasse is subjected
to the hot ?ue gases for 60% of the drying time,
and to the counter ?ow ofhot air for approxi 25
mately 40% of the drying time. This I ?nd
is an extremely e?icient drying method and en-,
ables me to reduce the number of drying tiers I
.over my prior method.
I claim:
Apparatus for drying loose vegetable ?bers
such as bagasse, comprising a closed vertical
casing, a vertical shaft rotatably mounted in
said casing, a conical distributor connected to
the upper end of the shaft, means for introduc
ing ?bers into the casing and upon said dis
tributor, a plurality of reticulated tiers spaced
throughout the length of the casing, means for
progressively conveying the ?ber ‘material from
as for example, a crank 45 and connecting rod
one tier to the next lower tier, an auxiliary fur 40
46 is_ mounted within the tube to discharge the nace, means for conveying hot ?ue gasesof ap
bagasse from the discharge cone 4|, the number ' proximately 750° F. from said furnace and intro
of strokes of the plunger 44 as well as the diam
ducing them into the top of said chamber in con
eter of the tube 42 being proportioned and de
tact with the ?brous material, a heat exchanger
45 signed so as to progressively discharge bagasse heated by said furnace, means for circulating 45
in accordance with the capacity of the drier and drying air through said heat exchanger and in- .
the rate of feeding material to the feed box II).
In order to provide an air lock against the ad
mission of atmospheric air into the drier‘ at the
50 discharge cone, the tube 42 preferably termi
nates in reduced discharge tube 41 effective to
retard the ?ow of dried bagasse except under
pressure from the plunger 43. The cooperating
action of the plunger 43 and the reduced dis
55 charge tube e?ect a compacting. of the bagasse '
?bers in the discharge tube effective to seal the
tube 45 against the entrance of air and also to
deliver the dried bagasse in partially compressed
batches, which are more advantageously baled in
60 baling presses than when. the material is loose
and ?occulent;
troducing it at approximately 250°-4o0° F. into
the opposite end of said chamber, and means for
withdrawing said hot ?ue gases and said cooler
drying air from said chamber at a point between
their points of introduction. the arrangement
permitting a current of hot ?ue gases moving
in the direction of travel of the ?brous material
during the ?rst operation of drying period, and 55
a current of cooler drying air moving in a coun
ter direction to the movement of the ?brous
material during the latter portion of the dry
ing period.
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