US2607679A - Apparatus for removing liquid from cotton linters - Google Patents

Description

Allg- 19, r1952 c. B. wElss ET AL APPARATUS 4FOR REMOVING LIQUID FROM COTTON LINTERS 5 Sheets-Sheet l Filed Feb. 17, 1947 Aug. 19, 1952 c. B. WEISS ET AL APPARATUS FOR RMOVING LIQUID FROM COTTON LINTERS 5 sheets-sheet 2 Filed Feb. l?, 1947 ME w11;

Aug. 19, 1952 I c. B. wElss ETAL 2,607,679

APPARATUS FOR REMOVING. LIQUID FROM COTTON LINTERS Filed Feb. 17, 1947 5 Sheets-Sheet 5 A femffgw i Y'Z 'j mi@ @el @Mw a um Patented Aug. 19, 1952 UNITED STATES PATENT OFFICE APPARATUS FOR REMOVING LIQUID FROM COTTON LINTERS Clarence B. Weiss and Charles W. Dean, Memphis,

Tenn., assignors to Buckeye Cotton Oil Company, Memphis, Tenn., a corporation of Ohio Application February 17, 1947, SerialvNo. 729,056

(Cl. S32-7) the discharge end of the conveyorbeing there formed into a dense plug which offers high resistance to thev movement'of the fibers through the conveyor, so that entrained liquid is expressed through the cylinder wall.

It is an object of the invention to provide apparatus of this general character which is capable either of deliveringfibrous material to a high pressure zone, or of discharging fibrous material from a high pressure zone, in a continuous manner and ,Without impairment of the pressure. jv Y y y A further object of the invention is the provision of a screw"` conveyor for the feeding of fibrous slurry inwhich a substantially constant pressure may be maintained at the conveyor outlet to resist the discharge of-material therefrom, regardless ofthe rate at which the materialis fed to the conveyor. In the preferred form of the invention, this object is achieved by the provision adjacent` the discharge end of the conveyorv of meansY to promote the formationof a compressedgplug of the discharging brous material, the IVplug forming means being yieldably supported so asto compensate for sudden variation in the plug density or in the load imposed upon the conveyor as the result of lack of uniformity of feed of material therethrough, whereby the density and quantityu of discharged material is maintained substantially constant. The conveyor is preferably of the screw type, having a screw shaft of uniform diameter and a continuous flight of uniform diameter and pitch operating in a cylindrical casing, but terminating short of the end, so that fresh material is continuously fed against and into the fibrous plug as lthe, plug moves toward and out of the discharge end of the conveyor. y Y

A furtherobject of the invention is to provide apparatus of the character described which is capable of releasing brous material to the atmosphere from a system in which substantial steam pressures are maintained, the discharging material serving to block the release ofpressure from the system. It is a feature of the invention that should accidental discharge of the blocking material occur, a mechanical safety device is automatically rendered operative to prevent escape of material or steam.

A further object of the invention is the provision of Vapparatus vfor substantially freeing fibrous material from a liquid `in which it is suspended or with which it is impregnated.

Still a further object of the invention is the provision of improved means for concurrently feeding and washing cotton linters, and for subjecting linters to a sequence of squeezing, impregnating, and treating steps. l

Further objects and features of the invention will be apparent from the following description taken in connection with the accompanying,

drawings, in which Figure l is a longitudinal sectional view of feeding apparatus embodying the principles of the invention and particularly adapted for use inthe discharge of fibrous materials from a pressure system to the atmosphere or to a system of reduced pressure;

Figure 2 is alongitudinal sectional view of a further form of the feeding apparatus shown in Figure l, modified to provide for washing of the fed materials;

Figure 3 is a longitudinal sectional view of a part of the apparatus shown in Figure 1 whereby the load imposed on the feeding apparatus may be regulated or controlled;

Figure 4 is a fragmentary longitudinal section illustrating a modied form of plug forming and retaining means;

Figure 5 is an enlarged side elevation of the end portion of the conveyor shown in Figures l and 2; and

Figurei is a view in section o-f a further modification, adapted particularly to the feeding of material at atmospheric or low pressure to a system of higher pressure.Y

In order to facilitate an understanding of the invention, reference is made to the several ernbodiments illustratedin theA accompanying drawsection I2 and an outletY Section I 3.

ings, and to the preferred use of such apparatus in the handling or treatment of cotton linters, specic language being employed to describe the saine. It will nevertheless be understood that no limitation of the invention is thereby intended, various alterations or modifications thereof, such as would fall within the province of those skilled in the art to 'construct or perform, being contemplated as part of the invention.

In the purification of the cellulosic content of cotton linters and like materials, it is convenient to process the materials, and to convey the materials from one processing zone to another, in the form of a slurry or suspension in liquid. In the course of processing it is sometimes necessary to vary the concentration or liquid to lint ratio of the slurry, to convey the material between zones in which different pressures are maintained, or to substitute one liquid medium for another. It is also often necessary to wash the material at various stages of the treatment to remove spentV liquor or imp-urities. The apparatus herein clescribed is effective in performing these and various other functions in a simple and uniform manner while feeding the material continuously, and is thusV particularly adapted to use in a continuous treatment operation. An important feature of the apparatus is its Iability to function properly even though the supply of material is irregular, or discontinuous. y

In Figure -1 of the drawings is illustratedA an Y apparatus particularly designed for the discharge of cotton linters or like fibrous material from a high pressure zone to a zone of lower pressure or to atmosphere. slurry is withdrawn from the high pressure zone through an inlet passage I9 into the inlet end of a screw conveyor. The conveyor consists essentially of a cylindrical housing having an inlet The inlet Sectio-n I2 of the conveyor housing is sealed, for instance by welding, to the inlet passage I0, and is impervious to liquid, so that loss of pressure from the highrpressure zone is prevented. The outlet section I 3 of the conveyor housing is perforated, slotted, or otherwise formed to present a liquid pervious wall, whereby liquid may be expressed from the slurry as it passes therethrough. A generally cylindrical casing I5 surrounds the outlet section I3, whereby expressed liquid is collected and led off vthrough a discharge passage I6. The employment of conventional means for maintaining back pressure in passage I6,lin order to minimize loss of steam pressure Ythrough the perforations in the outlet section I 3 of the conveyor housing, is usually desirable. K Y

A screw shaft 2Q, suitably journaled for rotation in the conveyor housing and driven from a convenient power source, not shown, is provided with oney or more continuous screw threads or helical conveyor flights 22. To simplify illustration, only one night is shown, `although it is found that the pressure distribution on the shaft is improved b-y the use of at least two coextensive nights to balance the thrust. The diameter` of the fiight is preferably only slightly less than the internal diameter of the housing in which it rotates, the screw Vhaving a working fit in the housing.V The diameters of the shaft and housing are uniform; proper operation does not depend on the use of a tapering feed passage, and is therefore independent of irregularity in the supply of material. Y

In this embodiment of the invention, the conveyor flight extends across the inlet passage and Fibrous stock in the form'of 4 termmates short of the discharge end of the outlet section i3 of the conveyor housing, it being observed that the annulus 24, on which the cylindrical perforated shell I3 and the casing i5 are mounted constitutes an extension of the housing. The purpose o-f terminating the conveyor flight short of the end of the housing is to permit the formation rearwardly of the conveyor flight of a plug of compressed fiber which is gradually fed out of the conveyor housing by the pressure exerted by the conveyor screw against successive incrementsA ofA thebrous'material, the materia1 thus discharged being continuously replaced by fresh material fed into the forward end of the plug by the conveyor. y

It is important to note that the perforations in the housing extend beyond the conveyor flight, to permit drainage of liquid from the highly compressed fiber, so that a dense plug may be formed, but terminate short of the end of the conveyor housing so that the rearward end o-f the fibrous plug may effectively block the housing to prevent leakage of pressure therefrom. Otherwise stated, the pervious section of the housing is contiguous to the trailing portion of the screw, extends beyond the screw, and terminates short kof the discharge end of the housing, as'shown inthe drawlng.

The pressure applied-by the screw to the fibrous plug is rather high,v and it 'is desirable to'` distribute the force exerted by the plug against fthe end of the conveyor flight. This result is achieved Yby deflecting the flight end into Ya plane substantially Y perpendicular to the axis of the conveyor shaft, as shown'more particularly in Figure 5 Yof the drawing. Y Asis apparent from this gure, the trailing face 26 of the conveyor flight denes such a plane, so that the pressure is distributed overa considerable area at the end ofthe plane. The end face 26 of the flight, as well/as the opposite, forwardly directed faceV 2'1 @may be further strengthened by the'addition of reinforcing metal, deposited byv welding. f Y j In orderto promotetheformationr of a dense plug at the discharge end of the conveyor, and to prevent the plug from blowing out-as the re sult of the pressure Within the zone or` system from which the fibrous material is removed, it is highly important to provide means whereby the conveyor outlet 'is` restricted and pressure is exerted against the rear of theplug. Furthermore, vit is important that the pressure soapplied to the rear of the plug be so varied as to compensateboth for momentary and. for prolonged variation in the plug density, in the frictional resistance exerted atV the plug periphery and along the shaft, and in! theV pressure tending to force the plug out of the conveyor. We prefer to employ for this purpose a conical mem'- ber 3i), mounted on and preferably rotating with the conveyor shaft 20,'for instance by a splined connection between the member 30 and the shaft,

whereby the member may be displacedaxially of the shaft toward and away from the discharge end of the conveyor'housing, the precise position of the member 3U on'n the lshaft at any instant being determined largely or entirely by operating conditions. Inorder that the member tk may be automatically displaced` in an axial direction in response t0 momentary or rapid change in operating conditions, a'coiled spring 34 is employed, this spring engaging the rrear face of the conical member 30 at one end and the forward face of a sleeve 35 at'its other end, sleeve 35 being keyed to shaft 20 for axial displacement thereon and rotation therewith, and serving as an abutment for the. spring 34. Thusif it be assumed that sleeve 35 occupies a fixed vposition axially of the shaft20, it will be perceived that the spring 34 will yieldingly urge the cone member 30 against the brous plug, and will be compressed or expanded to compensate for irregularities in the density of the plug, in the frictional resistance to movement of the plug, or in the discharging pressure applied thereto, the regulating action ybeing thereby quickly and automatically effected.

Since the action of the spring 34 in regulating the plug pressure is effective only as to relatively small but rapid changes in operating conditions, compensation for wider and more prolonged variaon in the plug density or the discharging pressure is obtained by adjusting the sleeve or abutment 35 axially of the shaft, whereby the range of movement of the conical member 30 permitted by the spring 34 is correspondingly displaced. For this purpose we may employ mechanism such as is shownmore particularly in Figure 3, whereby the position of sleeve 35 on the shaft may be altered during operation of the conveyor. Thus a sleeve 38l surrounding the shaft 20 and journaled for rotation in a boss 39 Yformed on a gear further treatment, itis preferable to provide picker pins 50 for engagement withthepl'ug as it emerges fromfthe conveyor. These pins may be mountedin bosses 5l formed on the' sleeve 35, so as to rotate wtih the conveyor shaft 20, whereby the fibrous plug is'e'ffcctively'disintegrated, knots and lumps are eliminate`d,and`sub sequent suspension of the fiber in liquid and its uniform impregnation bythe4 liquid is facilitated. It should be noted that the axialf'adjustment of sleeve or abutment as hereinbe'ffore described, to vary the pressure applied tothe plug by conical member 30, also serves to displace the picker pins axially. The position of the pins is thus determined independently of the actionf spring 34, and the pins are not permitted to yield on 'variation in the pressure applied thereto. as is member 30, but are positively positioned and rotated. The dewatered stock falls downwardly through an outlet passage 54,- eitherto the atmosphere or to a further treating `'zone of less pressure than that of the system from which the stock housing 40 engages the sleeve 35 through a thrust bearing 42, so that axial displacement of sleeve 38 in a forward direction, or toward the conveyor, eiects corresponding displacement of abutment sleeve 35, spring 34, and conical member 3D. Screw threads 44, formed on sleeve 38, are engaged by cooperating threads formed on a nut suitably journaled in gear housing 40 for rotation about the axis of shaft 20. Formed on the periphery of nut 45 is a worm gear 46, the latter being driven by a worm 41 keyed to a shaft 43, the latter being journaled in gear housing 40 for rotation on an axis transverse to the axis of conveyor shaft 20. It is thus apparent that by rotating shaft 48, the cone member 30 may be displaced axially to a position in which the requisite pressure is applied against the fibrous plug, minor and rapid variations in the applied pressure being exerted by the spring 34 as hereinbefore described. The adjustment may be made manually, for examplevby a handwheel on shaft 48, or automatically in response to variation in operating conditions as measured by the resistance offered to rotation of the conveyor'shaft 20 by the brous mass.

During the passage of the ber and entrained liquid through the outletportion of the conveyor, liquid is expressed from the fiber through the perforations in the conveyor housing, whereby the ratio of liquid to liber is materially decreased. Reduction of the liquid to liber ratio of from25 to 1 at the inlet end to 1:1 or even less at the discharge end may be readily effected by the apparatus described, and a plug may bel formed which is of suflicient length and density to retain pressures in the system of fromA to 175 pounds per square inch or even higher, provided the impervious portion of the housing immediately adjacent its discharge end is of suflicient length to enable the plug to 4block the housing, as hereinbefore pointed out, and provided the preceding pervious portion extends sufciently beyond the conveyor flight to allow adequate expression of liquid from the plug.

In order that the plug discharged from the conveyor may be prevented from packing beyond the conveyor housing, and may be broken up for is withdrawn. i' I In order to insure against possible blowing outl of the plug as the'result of unusual pressure conditions,V we prefer to discharge" the stockl from outlet passage 54 through a rotary valve housing 55, in which is supported for Arotation avalveA having a plurality of radially-.directed ,blades- 56. The valve blades 56 may "be driven throughgearing from any suitable sourcego'f power-'which is so designed as to transmitl only a predetermined maximum torque tothe valvejsufcient to move thefdischarging stock through the'housing 55, but insufficient to rotate'fthe VaIv'evVh'en the latter is subjected to the high pressureresulting from the blowing out of the fibrous plug? lhus-i'fthe plug should fai1 t0 hold the'fpressure, the rotary valve lwill jam and release of pressure inthe zone or system from which the material is'being'withdrawn will be' blocked. The valve -thus contributes an important safety factor inthe operation of the conveyor. ,y f

One method of driving' the rotary valve is illustrated in Figure 1, the valvejshaftbeing rotated through screw gearing A5l and belt ygearing 58 from a moto;` 59'. On theoccurrence of a plug blow-out, the belt gearing 58"wil-l"'slip and rotation of the valve will terminate'. Various other expedients effectiveto interrupt rthe drive in response to excessive torque, such as a slip clutch, a frangible pin, or a torque responsive'control for the motor circuit may `be employed lin lieuv of the drive shown inthe drawing-L .i

fresh material is pressed into its forward end.

Thus the plug remains in position and continues to block the conveyor even Vthough the supply of materia1 to the conveyor be irregular or interrupted. Again, irregularity of supply does not interfere with expression of liquid from the fiber, any material supplied tothe conveyor, ,however irregularly,l being fed by the screw against and into the fibrous plug. This is the result of employing a continuous and uninterrupted conveyor that terminates short of the end-of a uniformly dimensioned cylindrical housing in which it operates. l

Under some circumstances we nd it desirable to apply peripheral pressure'` tothe discharging fibrous plug, and may employ for this purpose the structure illustratedin Figure 4. Thus one or more axially extending'plates '60 may be pivoted to the annulus-.24ffor swinging movement discharging linters, and picker pins rotatable with said screw and extending toward the disthe liquid pervious wall of the housing embraces a substantial length of the trailing portion of the screw, extends beyond the screw, and terminates short of the discharge end of the housing.

CLARENCE B. WEISS. CHARLES W. DEAN.

REFERENCES CITED UNITED STATES PATENTS Number le of this patent:

Name Date Newnham Mar. 26, 1907 Muntzing Dec. 31, 1912 Olier Aug. 19, 1924 Lang Oct. 27, 1931 Wollenberg June 27, 1933 Brownlee Nov. 3, 1936 Asplund Feb. 7, 1939 de la Roza May 23, 1939 Bonotto Dec. 19, 1939 Lowgren et a1 Mar. 12, 1946 FOREIGN PATENTS Country Date Germany Apr. 27, 1939

Claims (1)

1. IN APPARATUS FOR USE IN PROCESSING COTTON LINTERS, THE COMBINATION WITH A SCREW CONVEYOR INCLUDING A CYLINDRICAL HOUSING HAVING A LIQUID PERVIOUS WALL AND SCREW HAVING A WORKING FIT IN SAID HOUSING AND TERMINATING SHORT OFF THE DISCHARGE END THEREOF, SAID SCREW HAVING A CONTINUOUS HELICAL FLIGHT OF UNIFORM PITCH AND DIAMETER THROUGHOUT THE LENGTH THEREOF, AND HAVING A SHAFT OF UNIFORM DIAMETER, MEANS DELIVERING TO THE INLET END OF SAID HOUSING A SLURRY OF COTTON LINTERS AND LIQUID, PLUG FORMING MEANS ADJACENT THE DISCHARGE END OF SAID HOUSING, SAID PLUG FORMING MEANS COMPRISING A MEMBER HAVING A CONICAL SURFACE INCREASING IN DIAMETER IN THE DIRECTION OF FEED OF THE MATERIAL, SAID MEMBER

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