US2632924A - Apparatus for cleaning fibrous materials - Google Patents

Description

L. L. BERTRAM ETAL 2,632,924

APPARATUS FOR CLEANING FIBROUS MATERIALS 4 Sheets-Sheet 1 March 31, 1953 Filed Aug. 8, 1951 26 CYCLONE SEPARATOR.

I PRIMARY CLEANER. I l :2 H 20 IO :l I 2 l---"'-1| I W CONVEYOR.

SECONDARY CLEANER.

BALE OPENING APPARATUS.

LEON L.BERTRAM ARTHUR F. MARTIN PHILIP A.POHLKE INVENTORS AGENT.

March 31, 1953 L. BERTRAM EI'AL 2,632,924

APPARATUS FOR CLEANING FIBROUS MATERIALS Filed Aug. 8, 1951' 4 Sheets-Sheet 2 PIC-3.2 LEON BERTRAM ARTHUR E MARTIN PHILIP A. POHLKE INVENTOR$ AGENT.

March 31, 1953 BERTMM ErAL 2,632,924

APPARATUS FOR' CLEANING FIBROUS MATERIALS Filed Aug. 8, 1951 4 Sheets-Sheet 3 g &\\\\\\\\\\\ QLEQNLBERTRLW A RTHUR iFZ MARTIN PHI'LI P A. POH L KE F '6. 5' INVENTORS BY W q. PM

AGENT.

March 31, 1953 L BERTRAM Ef AL 2,632,924

APPARATUS FOR CLEANING FIBROUS MATERIALS Filed Aug. 8, 1951 4 Sheets-Sheet 4 LEON L.BE.RTRAM a ARTHUR E MARTIN PHILIP A. POHLKE INVENTORS AGENT.

Patented Mar. 31 1953 APPARATUS FORCLEANIN G FIBROUS MATERIALS Leon L. Bertram, Hopewell, Va., Arthur F. Martin,

Wilmington, Del., and Philip A. Pohlke, Hopewell, Va., assignors to Hercules Powder Company, Wilmington, DeL, a corporation of Delaware Application August 8, 1951, Serial No. 240,834

6 Claims.

This invention relates to a process and apparatus for cleaning contaminated light, fibrous material. In a specific aspect this invention relates to a process and apparatus for cleaning contaminated cotton linters.

,In various commercial operations it is necessary' to remove contaminants from raw materials which arenormally light and fibrous prior to the use of these materials in plant operations. For 1 example, cotton linters are used in the I preparation of cellulose derivatives such as cellulose acetate, ethyl cellulose, nitrocellulose, and the like. However, before these cotton linters are subjected to the usual digestion operations and the chemical treatments necessary for converting them into the desired commercial products, it is usually necessary to remove contaminants such as dirt, dust, stones, field trash, cottonse'ed hulls and similar materials from the cotton linters. In mostcommercial operations it is desirable to produce a comparatively pure cellulose derivative, and the degree of purity of the product depends to a certain extent upon the cleanliness of the raw materials which, in v this instance, are the raw cotton linters. Thus, the necessity for procedures and apparatus to produce clean cotton linters or similar light, fibrous material is obvious. I Heretofore cleaning units of various types have been employed to clean light, fibrous materials, such as cotton linters, but these units have disadvantageous requirements or limitations which are deterrents to the use of the particular cleana ing apparatus. For example, liquid cleaning ap-' paratus andprocedures have been used, but the large amount of liquid, such as water, that must be handled greatly increases the operating costs. Air cleaning apparatus and procedures have also been employed, but the apparatus has been such that only limited and unsatisfactory quantities of material could be eiiectively cleaned within a given period of time.

It-is an object of this invention to provide a novel and improved process and apparatus for cleaning contaminated light, fibrous material.

It is another object of this invention to provide a novel and improved process and apparatus for cleaning contaminated cotton linters.

Further and additional objects of this invention will be apparent from the detailed disclosure hereinbelow.

The means by which the foregoing and other desirable objects are accomplished by the present invention and the manner of their accomplishment will be readily understood from the following description with reference to the accompanying drawings. In these drawings:

Fig. 1 is a schematic diagram of a process and apparatus for cleaning contaminated cotton linters. i

Fig. 2 is a part elevational and part sectional view of the primary cotton linters cleaner employed in the process depicted in Fig. 1.

Fig. 3 is a fragmentary cross sectional view of the perforate inner casing of the primary cleaner;

Fig. 4 is an elevational view of the perforate inner casing of the primary cleaner; 1

Fig. 5 is an enlarged fragmentary sectional view showing bafiie, reinforcing rod. and bar arrangement as employed for the perforate inner casing;

Fig. 6 is a plan view of one of the disk-like defiector plates to which the beater blades employed in the primary cleaner are attached;

Fig. '7 is a plan view of the primary cleaner showing the tangential outlet for the cleaned cotton linters;

Referring now to Fig. 1, the process'and apparatus for cleaningcotton linters will be described by following the cotton linters to be cleaned and as received atthe plant through a complete cleaning operation." Dry linters, obtained in fiuffed form by means of conventional bale opening apparatus ID, are pulled through line l2 by a stream of air into the cleaning apparatus 20 which will be described in detail by referring to the other drawings. The linters enter primary cleaner 20 beneath a deflector plate which leads the linters to a zone containing a plurality of rotating beater blades, and as a result of the operation of the beater blades ing.

the linters and contaminants are impelled by :linters fibers from the contaminants.

- :factor'y separation. cleaner 1:8 depends on thedeg-ree of contaminacover of cleaner 23 via line 22. From this condensing cover the air and cleaned linters are withdrawn tangentially by the action of suction fan 24 and passed via line 28 into cyclone separator 28. From separator 23 the cleaned cotton linters are withdrawn via line I l, and these linters are now ready for use in chemical operations for the production of cellulose derivatives. Air from which cleaned cotton linters have been separated zone Zhmay exhaust directly to atmosphene through ;fan 34 or may be returned to the conventional opening apparatus Hi via line 32 to entrain contaminated cotton linters for delivery to cleaner 2i).

The contaminants and linters fibers beaten through the inner perforate casing in cleaner 2B are collected in a sealed cavity in a-lower portion of cleaner 20, and they are discharged :from this cavity by being swept into screw conveyor 39 which operates against a weighted flap H or other similar device in order to maintain a seal. Cleaner 2!! can be operated in suchamannerthat the amount of contaminants removed from the 4 small, and this proportion increases as the severity of the cleaning action in cleaner increases. For most purposes adequate cleaning of the cotton linters can be effected in cleaner 2!! when from 5 to 10% of the total feed of cotton linters is passed with contaminants to cleaner I8 where this portion of the cotton linters is subjected to a second cleaning action.

Fig. 2 is a part sectional and a part elevational view- ;of primary cleaner in. .order to clean .the cotton linters this. cleaning apparatus subjects the contaminated cotton linters to the centrifugal force of a plurality of vertically dis posed beater blades inside a cylindrical casing having perforate or pervious side walls, and at the same time a stream of air is passed upwardly through the cotton linters. As a result of this :,-action, contaminating particles are separated from thelinters fibers. Referring now to Fig. 2 in :detaiL'thecleaning chamber is surrounded by imperforate casing NH, and air laden with con terminated cotton linters is introduced to the cotton linters is variable, and thus the degree of cleaning that is effected is also variable.

. When only a minimum amount of cleaning .is

required, the contaminants beaten through the :In that event the contaminants can be greater amounts-of linters fibers, and it-is sometimes desirable and economical to recover :such In an alternative mode of operation the contaminants tar-11d accomp nying linters after leaving screw conveyor :30 are passed :into -:a secondary cleaning zone l8. "Thissecondaryrcleanermay besimi- :lar'rto the primary cleaning apparatus 29 but of smaller size. Alternatively :a machine for producing hull fiber, such as the Reynelhware Memphis :defibrator, maybe employed. Other alternatives include the :use :of conventional beat- I singequipmentsuch as asFort Worth beaterwvhich is frequently employed producing "raw linters.

some cases, even a rough shaker screen system or an air separation apparatus will effect .satis- The choice of secondary tion :of the rejects which :come from conveyor 311 and on the amount of fiber loss which can f be tolerated the "process. 'ffiie objective .of

the secondary cleaner I8 is to produce concentrated contaminants which may he rejected .from theilinters purification process via line 238.. "The fiber-containing fraction from "the secondary cleaner 18 may, depending on :the apparatus which is 111sed,'be clean enough .to be employed :along with product withdrawn via line It from the primaryicleaning operation, but usually the degree iii-contamination of thisfraction from the .secondarycleaner 'vvilLbe .sumcient that the frac- =tion is returned to line H22 via line it and recycled through primary cleaner 2.0.

- the degree of cleanliness desired in the cleaned clinters issuing from :cleaner 2B. If it is necessary to efiect only a'limited cleaning action in cleanerifl, the proportion of cotton linters that passes to :cleaner .18 compared with the total iced of cotton linters to the system is relatively cleaner via conduit I02. In this drawing only one .inlet is shown for the introduction of the air and contaminated linters to the cleaning .-z,one,-but, alternatively, a series .or plurality of conduits can .be used in order to introduce the air and .contam-i-natedlinters to the cleaning zone lat-a multiplicity of points. Such alternative introduction at a plurality of points is sometimes desirable inorder to obtain an even distribution of air. and .cotton linters inthe cleaning chamber.

The cleaning action is carried out in the zone surrounded by solid bottom' plate Attend the vertically disposed perforate side walls 104.

v Within this cleaning .zone is rotor shaft casing M15 to whichgare attached disk-like solidplates 1.116,, and at the extremities of these solid disklike plates are attached .a vplurality of beater blades to]. It has been found desirable, in some cases. to employ eight beater blades in order to obtain efficient cleanin .of the linters, but any number of beater blades that produce the desired .clean-ingcan be used. Shaft casing IE5 is attached to shaft 1.88 .which operates combination with aseries ofhearings, housings, rubbber rings, oil and grease lines, and other conventional parts and equipment. -However, a detailed description .of these conventional parts is not essential to .an understandingof the inven .tion, .and these parts will not he referred to in detail .in this written description of the invention. At the base of shaft. tddspiral bevel gear its meshes with spiral bevel gear Hi3 which is attached to .drive shaft J H. This latter drive shaft is attached to a :driving mechanism (not shown) which serves as the driving means for revolving or 7 rotating ,plates H36 and heater blades 101.

In the operation of cleaner .Zlbthe speed of the driving mechanism is adjusted to produce the desired speed of the revolving beater blades, and air laden with contaminated cotton linters is introduced to the cleaning zone via conduit I 02 through the solid base plate T83. The point or points of introduction of the air and linters is closer to the central drive shaft than the beater blades I01, but plates IE6 are solid to prevent the upward passage of the air and linters therethrough. Consequently, the air and linters pass upwardly in the zone between the beater blades it! and the perforate casing HM. In its upward passage through :this annular space the cotton linters are subjected to the action of upward flowing air and the centrifugal force of the pose. disposed elongated metal bars spacedat regular intervals around the periphery .of the cleaning im tating "beater blades. The centrifugal force When the cotton linters and contaminants are thrown against perforate casing I04 by the centrifugal action'of the beater blades, the contaminants, which are heavier and have a greater momentum than the fibrous linters, are carried through the perforate casing while most of the fibrous linters are retained inside the perforate casing. As a result of this action the cotton linters that are removed from the cleaning zone by 'the upward flowing air are linters from which ing is subjected to fluctuating pressures on the inner'side. formation of a fibrous mat followed by partial These fluctuating pressures cause the stripping of the mat from the perforate casing and reclaiming of the fiber.

Perforate casing 104 can be a screen or other similar pervious device which will permit the passage of linters contaminants therethrough while permitting the passage of only a limited amount of linters through the casing. A heavy 'mesh wire screen or a perforated plate can be used. However, it has been found that a bar screen, similar'to that described in detail in Figs. 3, 4 and 5, is particularly suitable for this pur- This type of screen is a series of vertically zone. The bars are separated sufficiently to per mil; the passage of the contaminants between the bars, but most of the linters particles are retained within the cleaning zone. The actual dimensions of the individual bars can be varied, but, bars having an inner surface (the surface facing the beater blades) with a width of about /2. inch and spaced at intervals, of about inch, form a suitable screen for cleaning cotton linters.

It is also desirable to use tapered bars, 1. e., bars whose'outer surface \(the surface facing the imperforatecasing) isless than /2 inch and about inch in width. It will be understood that these specific dimensions are merely illustrative, and that screen bars having other dimensions can be used in practicing this invention. Fig. 3 is a plan view of a portion of perforate casing or bar screen I04 wherein'individual bar members H2 of the'complete bar screen are shown. Fig. 4 is an elevational view of bar screen Hi4. The inner surface of bar screen I64 is preferably sepa- "rated into a'series of individual sections by a plurality of bafiies l3 and I [4 which protrude inwardly from the bar screen. Fig. 5 shows an .enlarged' view of one of these baflles and the relationship of this baiiie toan individual bar mem- "ber of'the perforate screen. These bafiles are assembled between pairs of ring flanges I39, and the bafiiesandring flanges are suitably joined, for example, by machine bolts inserted in openings I31. The individual members of the bar screen are welded or otherwise suitably joined to the ring flanges at their points of juncture therewith. The individual members of the bar screen are connected and maintained rigidly in position'by reinforcing'rod H6 which is welded -or otherwise firmly connected to a U-support bar e132 encircling rod I33 :whichpasses through the members of the bar screen. It will be understood to break up the contaminants and free them from Consequently this section is termed they separate the bar screen into a plurality of separate zones, and the baffles willretain a portion of the linters undergoing the cleaning operation as a filtering mat on the bar screen. In a preferred modification of the equipment, lower baflie H3 protrudes inwardly a shorter distance than do upper baffles H4, e. g., lower baflie H3 may protrude inwardly about /2 inch and upper baflies H4 may protrude inwardly about'l inch, and as a result the thickness of the linters mat retained on the bar screen will be less below baflie H3 than above it. However, it will be understood that the length or inward protrusion distance of bafiles H3 and H4 can be varied; In other modifications, baffle H a can be 2inches long or longer whilebafiie H3 is about /2 inch, and other dimensions can be used within the scope of the invention. In some instances,'the baifles can be of equal length. The exact dimen-'- sions employed depend upon variable factors, such as the degree of cleanliness desired in the product linters, the severity required in the cleaning operation, the feed employed, and the like. When bafiie H3 has an inward protrusion of inch or less and when the beater blades iii! are setclose to bar screen it, it is noted that a large portion of the bars in this section of the screen are exposed, i. e., a stable mat of linters is not formed on the bars. This situation'may be desirable, since the entering linters feed is thrown forcibly against the screen in such a manner as the linters. a breaking sectionf 'of the bar screen. When the baffles protrude inwardly a greater distance,

as is desirable in the upper section of the bar screen, these bafiies retain a mat of linters on the bar screen about equal in thickness to the inward protrusion of the baffle. This mat of linters acts as a filtering means through which the heavy contaminating particles are able to pass but which retains on its surface the lighter fibrous linters,

and actually most of the separation of contami-,

nants from linters takes place in this section. Consequently, this section of the bar screen is termed the filtering sectionor, separating section. As a result the contaminating particles pass through the mat and bar screen and enter the annular space between bar screen m4 and external casing mi. The cleaned linters from which contaminating materials have been sepa; rated are retained within the area bounded by bar screen Hi l, and as a result of the action of theupward fiowing air passing through the space between beater bladesle'i and bar screen i634, these cleaned linters are removed from the cleaning zone into the condensing cover H7 which is disposed above the cleaning zone and outer casing'llll. 3

The breaking section or that portion of the bar screen below baffle H3 is an important feacurs which facilitatesthe removal of contaminantsfrom the linters fibers. Also; among the contaminants of the cotton linters are :cotton seed hulls, andin this bieaking sectionfthese c eaper hulls undergo .a siefihering action thatrremoves attached linters fibers. This defibering action facilitates the removal of the hulls from the cotton linters and results in an improved cleaning action. vAlso, the cotton linters, before cleaning, contain large pieces. of field trash. and other simi- .lar material. Upon striking the bar screen in the breaking section these large contaminants are brokeniinito pieces sufiiciently small to pass through the bar screen. As a result or these various actions discussed above, the breaking section improves the overall operation efficiency of the cleaning unit.

A substantial portion of the linters fibers that 'passzthrough perforate casing 1:843 with ccntam-i- .nants. do so in .the breaking section since a stable mat of linters fibers is not formed in this section of the screen or casing. :In order to decrease the amount of fibers passing through casing :LM the breaking section thereof can be made solid and impervious. In that event, this section of .the casing would still operate as a breaking section without efiecting a cleaning of the linters by removal of contaminants. The cleaning action in this modification is eiTec-ted inv the filtering sect-ion where :the mat of fibers on the casing aids in the separation of contaminants vfrom fibers and in the prevention of the passage of fibers through the casing.

Condensing cover H? has a maximum diameter greater than the diameter of the cleaning zone bounded by bottom plate Hi3 and bar screen 1104. Also, the maximum diameter of condensing cover i I! is considerably greater than the width of the passageway between beater blades l! and bar screen Hi4. Consequently, the velocity of the air as it passes through condensing cover H7 is considerably less than the velocity of the air passing through the linters cleaning 'zone. Also, the air upon entering condensing cover H1 tends to pass in an upwardly spiraling path, and the air and cleaned linters are Withdrawn. from cover 'Hl through tangential outlet 1 [8 in an upper portion of that cover. This cover is also provided with tramp separator H9 which removes heavy pieces of. metal, stones or other contaminating materials'that may still be contained in the cotton linters. A damper in. the lower portion of tramp separator it is used for clean-out purposes and to prevent the .flow of air and cleaned linters through separator H9. A deflecting cone 26 is inserted in the upper center portion of condensing cover ill :in order to aid in producing :the desired spiraling. path of air and linters through the cover and, also to provide a means for in-- troducing'additional quantities of air to the cover by suitable adjustment of slide gate iii. The velocity of air and linters passing through the cleaning zone can be varied by suitable adjustment of gate I25. By adjustment of gate 525 the actual suction on the cleaner can :be varied, and in this manner the period of time during which the linters are retained in the cleaner can be varied as required to efiect the desired cieaning of the linters.

Contaminants which were separated from the cotton linters by passage through bar screen HM are collected above the base plate for outer casing Hill which contains .an opening I22 permitting passage of these contaminants to screw conveyor .38 which conducts the-contaminants andany accompanying linters away from primary cleaner 20; As indicated previously screw, conveyor 30 operates a ainst a weight loaded flap zl61orssimilar device .ior maintaining a seal. If the seal .is broken, a constant flow of air is established through screw conveyor 3:0 counter to the flow-of material, and this flow of air into cleaner 2!) leads to plugging of the bar screen with the .resulting failure to clean the contaminated cotton linters. When the-cleaner is in operation, the rejects cavity or annular space between outer casing l9! and the inner casing formed by plate 103 and screen we is at a subatmospheric pressure, and this pressure is maintained during thecleaning operation. For efiicient-removalof contaminants from cleaner 29, the zone between plate I83 and the bottom of casing 19! is provided with sweepingimeans 123 whose arms are-attached to casing lZri. This latter casing operates in communication with ring gear 125 which is meshed with spiral bevel gear l-28-attached to drive shaft I21. Thisdrive shaft is attached to a driving means (not shown) which serves to rotate shaft 12.! and thus effect the rotation of sweeping means I23. By the operation of this mechanism the contaminantsor rejects from the feed as well'as any accompanying cotton linters areswept into opening 122 and thence removed from the cleaner via screw conveyor 39. The lower portion'of primary cleaner 20 which is bounded by easing I28 is an oil reservoir and the entire cleaning mechanism is supported by base plate 529.

Fig. 6 is a plan view of one modification of disk-like, deflector plate 186 to which are attached eight beater blades 10?. Plate I66 is provided with an opening in the center for insertion of shaft casing 165, and plate I06 is solid in order that air and linters to be cleaned must pass through the space between its periphery and bar screen NM. The spaces between the beater blades [ill in the periphery of plate I96 are curved inwardly or concavely to aid the passage of air and linters through the cleaning zone.

Fig. '7 is a plan view of cleaner 29 showing condensing cover Ill, deflecting cone I20, tangential outlet H8 and. tramp separator I #9.

It will be realized by those skilled in the art that the cleaner described in detail above is quite versatile, that it can be used to clean markedly varying loads of cotton linters or similar fibrous material, and that a product of widely varying degrees of cleanliness can be obtained from this cleaner. For example, the amount of cleaning that is effected can be varied by suitable adjustment of the length or inward protrusion of baffies H3 and EM, particularly the latter. If the length of these baflles is increased, the linters are retained in the cleaning unit a longer period of time, and, consequently, greater quantities of contaminants are removed from the linters. The velocity of the air and the rate of feed of contaminated linters are subjectto variation, and as these conditions are varied the degree of-cleaning that is performed in the cleaner is varied. Slide gate B28 is adjustable and useful for varying the cleaning time and degree of cleaning for a contaminated linters furnish. The versatility of the cleaner is complemented by the fact that the rotational velocity of revolutions per minute of the beater blades can be varied, and at the higher velocities an improved cleaning of the linters results. l-loweven'increasing the rotational velocity of the beater blades tends to increase the heating of the linters in the cleaning zone, and this heating may damage the linters or even result in a fire unless suitable precautions are taken .for its prevention. For example, the incoming air velocityaorrthe feed rate :of contaminatedglintersLoan-j be varied, tof h removalfrom the cleaner. Also, the lengthvof baffles [Band I l4or the settingof slide gate l2! can beifadju'stedto'vary the residence time of the linters the cleaner-,arid in this manner undesirable heat can be removed. Numerous other modifications of the operating conditions and of the; and o atiqn, o parts a Well a i ill? lmethqd i i DWI-W 1 W i the Scope, Q t invention will be apparent to those skilled in the art from the above disclosure.

What we claim and desire to protect by Letters Patent is:

1. A cleaner for a contaminated light, fibrous material which comprises, in combination, a

cylindrical imperforate casing having a bottom .apertured for a shaft and having a discharge opening in said bottom, said casing being open at V the top; a shaft extending upwardly through the aperture in the bottom of said. casing; a plurality of disk-like plates attached to said shaft and subrotating said shaft.

2. A cleaner for contaminated cotton linters which comprises, in combination, a cylindrical imperforate casing having a bottom apertured for a shaft and having a discharge opening in said bottom, said casing being open at the top; a shaft extending upwardly through the aperture in the bottom of said casing; a plurality of solid disk-like plates attached to said shaft and substantially perpendicular thereto; a plurality of beater blades attached to said plates and disposed substantially parallel to said shaft; a second cylindrically shaped casing open at the top and disposed between said beater blades and said imperforate casing and forming an annular space with said imperforate casing, said second casing having a perforate side wall and a series of baflles vertically spaced and extending inwardly toward 7 said beater, blades and dividing said perforate side wall into a plurality of separate sections;

a cover disposed above said perforate casing to enclose said annular space and having a diameter greater than the diameter of said perforate casing and having a tangential opening for withdrawing cleaned cotton linters; means for introducing air laden with contaminated cotton linters to said perforate casing; and means for rotating said shaft.

3. A cleaner for contaminated cotton linters which comprises, in combination, a cylindrical imperforate casing having a bottom apertured for a shaft and having a discharge opening in said bottom, said casing being open at the top; a shaft extending upwardly through the aperture in the bottom of said casing; a plurality of solid disk-like plates rigidly attached to said shaft and perpendicular thereto; a plurality of beater blades attached to and spaced at regular intervals around the outer extremity of said plates and disposed substantially parallel to said shaft; a second cylindrically shaped casing open at the of; elongated, vertically disposed plates spaced to permitpassage of cotton linters contaminants betweensaid plates, while retaining fibrous cotton;linters particles inside said imperforate casing, said bar screen beingdivided into a plurality of separate sections by a series of baflles vertically spaced and extending inwardly toward said beaterblades withthe lowermost baffle extending inwardly a shorter distance than the uppermost baiiie; a cover disposed above saidperforate casing to enclose said annular space and having a diameter greater than the diameter of said perforate casing and having a tangential opening for withdrawing cleaned cotton linters; means for introducing air laden with contaminated cotton linters to said perforate casing; and means for rotating said shaft.

4. A cleaner for contaminated cotton linters which comprises, in combination, a cylindrical a shaft extending upwardly through the aperture in the bottom of said casing; a plurality of solid disk-like plates rigidly attached to said shaft and perpendicular thereto; a plurality of beater blades attached to and spaced at regular intervals around the outer extremity of said plates and disposed substantially parallel to said shaft; a second cylindrically shaped casing open at the top and disposed between said beater blades and said imperforate casing and forming an annular space with said imperforate casing, the bottom of said second casing being a solid plate with an opening for the introduction of air laden with contaminated cotton linters and the side wall of said second casing being a perforate bar screen of elongated, vertically disposed plates spaced to permit passage of cotton linters contaminants between said plates while retaining fibrous cotton linters particles inside said imperforate casing, said bar screen being divided into a plurality of separate sections by a series of baffies vertically spaced and extending inwardly toward said heater blades with-the lowermost baffie extending inwardly a shorter distance than the uppermost baffle; a cover disposed above said perforate casing to enclose said annular space and having a diameter greater than the diameter of said perforate casing and having a tangential opening for withdrawing cleaned cotton linters, said cover having a second opening for the introduction of air therethrough; means for introducing air laden with contaminated cottonlinters to said perforate casing; and means for rotating said shaft. 5. A cleaner according to claim 4 wherein th lowermost bafile extends inwardly toward the beater blades a distance sufllcient to retain cotton linters on the inner surface of that section of the bar screen below said lowermost baflie in an amount sufficient to cover only a portion of the inner surface of that section of the bar screen below said lowermost baffle and the uppermost baffle extends inwardly toward the beater blades a distance sufiicient to retain cotton linters on 6; cleaner according to claim 4 wherein a sweeping device rotatable in a plane parallel with thebettom of saidimperforateeasing'is disposed in the space between the bottom of said imperfOrate-casing and the bottom of said'perforate- 5 casing;

LEON L. BERTRAM. ARTHUR F. PHILIP A. POI-ILKE;

REFERENCES CITED The following references are of record in the.

file of this patent;

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