US3299477A

US3299477A - Apparatus for processing crushed fibrous stalks

Info

Publication number: US3299477A
Application number: US353407A
Authority: US
Inventors: Kenneth M Gunkel
Original assignee: WR Grace and Co
Current assignee: WR Grace and Co
Priority date: 1964-03-20
Filing date: 1964-03-20
Publication date: 1967-01-24
Anticipated expiration: 1984-01-24

Description

K. M. GUNKEL 3,299,477.

APPARATUS FOR PROCESSING CRUSHED FIBROUS STALKS Jan. 24, 1967 4 Sheets-Sheet 1 Filed March 20, 1964 TO AIR EXHAUST FAN INVENTOR KENNETH M. GUNKEL Jan. 24, 1967 K. M. GUNKEL APPARATUS FOR PROCESSING CRUSHED FIBROUS STAL-KS Filed March 20, 1964 4 Sheets-Sheet INVENTOR KENNETH M. GUNKEL ATTORNEY Jam. 24, 1967 K. M. GUNKEL 3,299,477

APPARATUS FOR PROCESSING CRUSHED FIBROUS STALKS Filed March 20, 1964 4 Sheets-Sheet AIR FROM BLOWER INVENTOR KENNETH M. GUNKEL ATTORNEY Jan. 24, 1967 K. M. GUNKgL 3,299,477

APPARATUS FOR PROCESSING CRUSHED FIBROUS STALKS Filed March 20, 1.964 1 4'Sheets-Sheet TO EXHAUST FAN TO EXHAUST FAN FIG. 5

INVENTOR KENNETH M. GUNKEL ATTORNEY United States Patent 3,299,477 APPARATUS FOR PROCESING CRUSHED FIEROUS STALKS Kenneth M. Guukel, New Canaan, Conn., assignor to W. R. Grace 8: Co., New York, N.Y., a corporation of Connecticut Filed Mar. 20, 1964, Ser. No. 353,407 12 Claims. (Cl. 1990) This invention relates to an apparatus for processing fibrous vegetable materials so as to separate them into two portions, one of which is substantially pith free and the other of which contains a major proportion of the original pith.

In summary this invention is an apparatus for processing crushed fibrous stalks containing pith to separate the pith and fibers comprising a rotor having laterally extending hammers, a screening element surrounding the rotor and having inlet and outlet ends, and means for passing a stream of air along the outer surface of the screening element to carry away the pith passing therethrough.

The preferred embodiment of the invention is an apparatus for processing crushed fibrous stalks containing pith to separate the pith and the fiber comprising an axially upright drive shaft, enclosed in a sealed housing, a rotor having laterally extending pivoted hammers and detachably mounted to the upper end of the drive shaft; a screening element surrounding a rotor and concentric therewith; a first chamber means for directing a stream of air around the screening element, surrounding at least a portion of the screening element, and including means for detachably supporting the screen element and means permitting removal of the screen element from the position surrounding the rotor; a second chamber means surrounding the drive shaft and having an opening in the top thereof connected to the bottom edge of the screening element for receipt of processed fibers passing from the screening element and wherein the second chamber includes inlet and outlet openings, an air exhaust means connected to the outlet opening thereof and a damper means connected to the inlet thereof for regulating air flow through the second chamber, and wherein the crosssectional area of the second chamber below the screening element is greater than at the inlet thereof whereby controlled air flow through said second chamber is facilitated; an upright, rigid drive shaft support mounted on the floor of said second chamber and supportingly attached to the drive shaft; a preliminary fibrous stalk and tramp iron separation means connected to the inlet of said screening element by means of conduit, said preliminary separation means including a chute means having an open top and bottom and having aligned openings in two opposite walls thereof, one of said aligned openings being connected to the said conduit means.

The apparatus of this invention separates fiber-containing stalk materials into fiber and pith fractions. The separated fractions can be used as desired. For example, the fiber portion can be used for pulp in the paper industry or as a basic raw material for making hardboard of various types. The pith fraction can be used as animal feed, chicken litter, animal bedding, or can be burned as fuel in industrial or heating boilers. The machine of this invention is especially suitable for obtaining substantially pith free fiber from sugar cane bagasse for paper-making purposes, but its use is not restricted to sugar cane bagasse alone. The machine is also suitable for processing other materials such as straw, flax, rice hulls, and similar vegetable matter.

The operation and maintenance of pith-fiber separators previously known was difiicult because of several design characteristics. Rotor and drive assembly support structure in the inlet end of the separating zone restricted the flow of material therethrough, as shown in Patent No. 2,545,159. Tangential inlet and discharge outlets from the treating zone and use of deflecting, twisted hammers to facilitate transport of the raw material through and from the treating zone as shown in Patents No. 2,678,169 and 2,729,858 permitted rotation of the rotor in only one direction. As a result, the hammers had only one effective wearing surface and a correspondingly shorter useful life. Previously known pith-fiber separators were rigid assemblies which could not be conveniently modified to provide material inlet and outlet directional relationships which were suitable for a variety of factories with varying layouts. A machine had to be individually designed for each factory layout by means of expensive modifications, and could not be conveniently employed in several factories. Furthermore, the heavy duty machine previously known could not be easily transported and installed in new locations as desired.

One of the objects of this invention is to provide an apparatus for separating pith and fiber fractions from vegetable matter in a continuous economical process and wherein the materials being treated are fed into the apparatus and discharged from the apparatus in an efiicient manner.

It is another object of this invention to provide an apparatus from which the screening element and rotor assembly and drive assembly can be readily removed for maintenance.

It is another object of this invention to provide an apparatus which is unitary and compact and which can be readily transported to new locations as desired.

It is still another object of this invention to provide a symmetrical rotor and casing assembly allowing rotation of the rotor in either direction without replacement of the hammers; by simply reversing the direction of rotor rotation, new hammer impact surfaces are made available for use, thereby doubling the useful life of the hammers.

It is a further object of this invention to provide an assembly which allows easy orientation of the screen casing about the screening element whereby the pith and fiber outlets can be individually aligned to suit any factory layout encountered.

Other objects and advantages of this invention will become apparent with the following description and a consideration of the construction shown in the accompanying drawings.

In the drawings:

FIGURE 1 is a side sectional view of the apparatus of this invention.

FIGURE 2 is a front sectional view of the apparatus of this invention.

FIGURE 3 is a detailed sectional view of the rotor assembly.

FIGURES 4 and 5 are side sectional views of preferred embodiments of the apparatus of this invention.

Referring to FIGURES 1 and 2, the rotor 10 carrying the pivoted hammers 12 is supportingly attached to the drive shaft 14. The drive shaft is sealingly enclosed in the shaft sleeve assembly 16, and is supported therein by bearing assembly 18. The drive shaft and sleeve assembly is supported by ring 19 which is supported by spider 20. The drive shaft and rotor assembly is maintained in axial alignment in the screening element by slip joint 21. Screening element 22 surrounds the rotor assembly 10 and is spaced apart from the hammers 12. The clearance between the hammer tips and the plate can be varied to suit the users preference merely by cutting off a portion of the hammers as desired. With this technique the hammer blades can be cut back in increasing amounts in each horizontal plane to form a tapered rotor and hammer assembly or any other configuration which may be desired.

The screening element 22 rests on flange 24 in the lower wall of the screen casing 26 and is bolted to the casing through attached flange 27. The screen casing includes an air inlet 28 with air control damper 30, and air outlet 31 in communication with an air exhaust means. The air stream drawn through the screen casing and around the screen is controlled by operation of damper 30. Reduced pressure in the first chamber resulting from closing of the damper 30 can be used to increase the flow of pith through the screening element.

The screening element 22 can be a screen or plate perforated in whole or part or a plurality of bars spaced apart to provide screening openings. The screening element is generally circular in cross-section and is shaped to maintain the desired operating distance between the hammer tip and the screen. The screening element 22 is preferably a perforated cylinder having a wall thickness which is less than the diameter of the perforations. The fiber removal chamber 34 has an opening in its upper surface connected to the lower end of the screening element 22 for receipt of the depithed fiber material. The chamber casing includes an air inlet 36 with damper 38 and air outlet 40 in communication with an air exhaust means. Air drawn from the inlet 36 to the outlet 40 removes the depithed fibers collecting in the fiber removal chamber. By control of the damper, the pressure in the fiber removal chamber can be reduced so as to draw air through the inlet of the screening element, through the separation zone defined by the screening element, and into the fiber removal chamber, thereby facilitating the passage of the materials being processed in a stream of air through the the separating zone. The symmetry of the screen casing permits rotation of the rotor in either direction.

A preliminary stalk separation means 43 can be connected to the top of screening element 22 by a feed conduit 44 which can be either rigid or flexible. The feed conduit can be clamped to a flange 46 which is in turn clamped to the top of the screen element 22. The preliminary stalk separator comprises a chute 48 having an open top for receipt of the stalks to be separated and an open bottom for discharge of the rejected material. Chute wall 50 has an opening connecting to the feed cn duit and the opposing wall 52 has an opening opposite the opening in the first wall. Air drawn into the separation zone by the air exhaust means of chamber 34 passes across the path of material falling through the chute 48 and into the feed conduit. The stalk material is drawn into the feed conduit, and the tramp iron, stones, and other extraneous materials fall through the bottom opening of the preliminary separator chute. Baflies and shrouds can be employed in the chute 48 to direct the flow of material.

The drive shaft 14 is driven by the V-belt drive 54 which is in turn driven by motor 56. The shaft rotation speed can be varied merely by changing the ratios of sheaves 58 and 60. The motor 56 is wired for reversible rotation.

The individual components of the apparatus can be mounted by bolts or welds on suitable cross braces 62 and upright supports 64 to form a unitary structure which can be transported from factory to factory with-out disassembly.

Referring to FIGURE 3, the rotor head has a tapered bore 66 which mates with a tapered end portion and keyway 68 of the drive shaft 14. The rotor head is attached to the drive shaft 14. The rotor head is attached to the drive shaft by means of castellated nut 70. The hammers extend into annular grooves 72 in the rotor head and are pivotally mounted on rods or bolts 74 passing through the aligned holes in the rotor head. The rotor head can be made from a single piece having grooves machined therein, or it preferably can be formed 4 from a series of discs having varying alternating large and small outer diameters. If a plurality of such discs are employed, the hammer arrangement can be regulated by proper arrangement of the discs. Two or more hammers can be employed in each annular groove. The hammers must be evenly spaced to maintain rotor balance.

The hammers can be made rigid and non-pivotal, if desired, by providing a plurality of holes in each hammer and in the corresponding portions of the rotor, and by passing a plurality of rods through each hammer. The hammers are designed to provide the requisite impact action when traveling in either direction about the rotor axis. Since material flow through the hammer zone is obtained by gravity and air flow, the use of unsymmetrical, twisted blades is unnecessary.

Disassembly of the apparatus for maintenance is rapid and convenient. After the feed chute 44 and flange 46 are unclamped and removed, direct access to the rotor is obtained. The rotor is'disc-onnected from the drive shaft and lifted from the assembly. Screening element 22 can be removed by unbolting it from the screen casing and lifting it therefrom. The drive shaft can be removed by removing sheave 60, unbolting the drive shaft casing from the spider support 20, and lifting the drive shaft, while still sealingly encased in the casing, from the device.

In a preferred embodiment of the apparatus as shown in FIGURE 4, the screening element 22 is bolted to the screen casing through flange 76. The spider mounting 20 shown in FIGURES 1 and 2 is avoided by supporting the rotor and drive assembly entirely upon support 98. The drive shaft assembly is attached to the support by bolting collar 92 to flange 91 which is permanently mounted on support 90. The fiber removal chamber 84 diifers from the corersponding chamber 34 shown in FIGURES 1 and 2 in providing increased cross-sectional area for air flow below the screening element outlet end whereby simultaneous flow of air across the floor of chamber 84 and through the hammer zone can be more easily controlled. Other floor contours which provide this function can be used. Use of a floor sloping from the air inlet 86 to the outlet 88 offers improved fiber removal from the chamber. The concrete fill illustrated in FIGURE 4 provides a superior attrition resistance and strengthens the support assembly 90.

The air exhaust means 32 and 42 can be mounted in

outlets

31 and 88, respectively, or can be separately mounted and connected to the outlets by conduits.

In the preliminary separator 100, air is drawn across the path of material falling through the chute by air exhaustion through outlet 88 as in the device shown in FIG- URES 1 and 2. The air flow across the chute is supplemented by air directed from a blower through conduit 102. This forced draft can be obtained from an auxiliary blower or can be obtained from the exhaust blowers 32 or 42.

The preferred apparatus as shown in FIGURE 4 is of simple unitary construction. The upper screen 22 and casing 80 are supported by the walls of lower chamber 84. The rotor support 98 'and the walls of chamber 84 are supported on plate 96. The floor of chamber 84 is formed from concrete poured between the support 90 and the vertical walls. The added strength resulting from this design can be further increased by employing braces between the support 90 and adjacent walls which can be embedded in the concrete fill. The conical design of support 98 is sufficiently rigid to support the rotor assembly without the use of spider braces as shown in FIGURES l and 2. Other support designs which provide the requisite support rigidity can be employed.

The bottom assembly of the drive shaft and sleeve forms a slip joint 94 with the bottom wall 96 whereby it is stabilized against lateral movement. The cylindrical screening element 22 is removed by loosening bolts 98, and the rotor head assembly 10 is removed from the drive shaft 14 as explained above with respect to FIGURE 1. In the apparatus of FIGURE 4 the drive shaft and sleeve assembly 16 can be thereafter removed by loosening the bolts connecting collar 92 and flange 91, removing sheave 60, and raising the assembly from its position. With this design the shaft while still enclosed in its sealed housing can be easily removed, allowing later disassembly for maintenance at a cleaner location.

In the operation of the apparatus of this invention, the crushed stalks or other materials to be processed are dropped into the top of the chute 48 and the stream of air drawn into the flexible conduit 44 picks up and carries the lighter stalks to be processed. Suspended in the air stream, the stalks are carried into contact with the pivoted hammers 12 for separation of the pith and fiber. For processing of bagasse, a hammer tip velocity of about 20,000 ft. per minute is preferred. The pith, smaller in size than the perforations in the screening element, is thrown, blown, and drawn through the perforations when separated from the fiber, and is picked up by the stream of air directed around the screening element by the screen casing 80. The depithed fiber fraction is drawn from the separation zone into the fiber removal chamber 84 by means of gravity and the current of air drawn through the impacting zone by air exhaust means 42. The fibers falling into the lower chambers are swept therefrom by means of a stream of air passing from the air inlet to the outlet 88. By controlling the position of damper 38 in air inlet 86, air velocity through the preliminary separator and separation zone can be controlled to provide the desired degree of preliminary separation and rate of feed of the stalk material to the impacting zone.

The preferred embodiment of the invention shown in FIGURE 5 differs from the devices shown in FIG'URES 1 and 4 in several respects. Screen casing 102 is provided with a cylindrical ring 104 in the top thereof which is adapted to slip into the screening element 22. The screen casing 102 is also provided with a cylindrical ring 106 on the bottom thereof which is supported by the top of the lower casing 108. The screen casing is thereby adapted for rotation about the rotor axis, and the outlet 31 can be positioned at any angle. This flexibility of alignment allows the device to be installed in factories having a variety of layouts withouts extensive modification. The apparatus is positioned to align the outlet 88 in the desired direction, and then the screen casing 102 is rotated to align the outlet 31 in the desired direction. The screen casing, when aligned, is fixed in position by means of strap 110.

The drive shaft and sealed casing 112 is mounted in tapered seat 114 in support 116, thus providing automatic alignment of the rotor in the screen casing. The support 116 is rigidly mounted on the floor of the casing 108. The design shown offers an advantage over the conical contour of support 90 in FIGURE 4 in that it can have 'a smaller vertical cross-sectional area and provide less resistance to the flow of air across the floor of the chamber.

The drive shaft and sealed casing is held rigidly in the tapered seat 114 by means of the anchoring assembly 116. The drive shaft casing forms a slip joint with the floor 118 of the chamber casing 108 and is attached to the floor 118 by means of keeper ring 120 and split ring 122.

If desired the apparatus can be operated without the preliminary stalk separator 48 shown in FIGURES 1, 2 and 4. In that event, the materials to be processed can be dropped directly into the top of the hammer zone. Feeding of the raw material can be either manual or by means of an automatic feeding mechanism.

The apparatus as explained and illustrated in the drawing employes exhaust fans to produce the desired air currents. However, portions or all of the system can be operated as a forced draft system by placing forced draft fans in the screen casing air inlet, or in the lower chamber air inlet or both. Air flow control can be obtained by the operation of bafiies located in the air outlets in the system. In both the induced and forced draft systems, diiferential air pressure across the impact area provides eificient passage of material through the hammer zone.

The apparatus of this invention has several advantages over the previously known systems. The screening elements, rotor head, and drive shaft assemblies can be easily removed for maintenance. Furthermore, because of the design employed, supporting structure in the main material flow stream through the inlet and outlet of the screening element is avoided whereby passage of the material being treated is facilitated. In addition, the system provides continuous, economical operation. Because the assembly can be mounted on a movable frame such as that shown in FIGURE 4, it can be readily transported from one factory to another in order to conveniently process geographically separated accumulations of the fibrous materials.

I claim:

1. An apparatus for processing crushed fibrous stalks containing pith to separate the pith and fibers comprismg (a) a rotor having laterally extending hammers,

(b) a screening element surrounding the rotor, and

having an open inlet and outlet ends, and

(c) a casing means surrounding the screening element for directing air around the outer surface of the screening element and having opposed, spaced apart walls terminating at a surface of the screening element.

2. An apparatus as described in claim 1 wherein one of said opposed walls of the casing means comprises support means for the screening element and the other of said opposed walls includes means in sliding engagement with the surface of the screening element.

3. An apparatus described in claim 1, comprising (a) drive means detachably connected to and supporting the rotor at the outlet end of the screening element.

4. An apparatus described in claim 3, wherein the drive means has a tapered end portion, and the rotor is mounted in a self-centering position on the tapered end portion.

5. An apparatus for processing crushed fibrous stalks containing pith to separate the pith and fibers comprising (a) an axially upright drive shaft,

(b) a rotor having laterally extending hammers detachably mounted on the upper end of the drive shaft,

(0) a screening element having a circular cross-section and surrounding the rotor and concentric therewith, said screening element further having a :top and bottom opening,

((1) a first screening element casing means for directing a first stream of air around the screening element and surrounding at least a portion of the screening element, and

(e) a fiber removal chamber casing surrounding the drive shaft and having an opening in the top thereof communicating with the bottom opening of the screening element for receipt of processed fibers passing from the screening element, and having air inlet and outlet openings, the fiber removal chamber casing having a bottom wall and including means for passing a second stream of air separate from said first stream of air from the air inlet opening to the air outlet opening thereof at a pressure less than the air pressure at the top opening of the screening element whereby a stream of air separate from said first stream of air is passed through the impact zone defined by the screening element to facilitate passage of fibrous materials therethrough and a stream of air separate from said first stream of air is directed across the lower portion of the fiber removal chamber casing for removal of fibrous materials therefrom.

6. An apparatus as described in claim 5, wherein the fiber removal chamber casing includes an air exhaust means connected to the air outlet opening thereof and a damping means in the air inlet opening thereof for regulating air flow there through;

7. An apparatus as described in claim 5, wherein the drive shaft is mounted on a support means attached to the bottom wall of the fiber removal chamber casing.

8. An apparatus as described in claim 5, wherein the cross-sectional area of the fiber removal chamber casing below the screening element bottom opening is greater than the cross-sectional area of the air inlet thereof.

9. An apparatus as described in claim 5, wherein the bottom wall of the fiber removal casing includes a floor sloping downward from the inlet opening to said outlet opening and the drive shaft is mounted on a support means attached to the bottom wall of the fiber removal chamber casing.

10. An apparatus for processing crushed fibrous stalks containing pith to separate the pith and the fibers comprising (a) a rotor having laterally extending hammers,

(b) a screening element surrounding the rotor, and

having open opposite inlet and outlet ends,

(c) a means for passing a stream of air along the outer surface of the screening element to carry away the pith passing therethrough,

((1) air blowing means for directing a stream of air into the inlet end and out of the outlet end of the screening element whereby fibrous materials are drawn by a stream of air into and through the processing zone,

8 (e) preliminary separation means connected to the inlet of the screening element for separating the fibrous materials :to be processed from extraneous materials.

11. An apparatus as described in claim 10 wherein the preliminary separating means comprises (a) a conduit having open ends, the outlet end connected to the screen inlet whereby air is directed into the conduit inlet by said air blowing means, and

(b) means for directing the passage of fibrous materials through the stream of air passing into the conduit inlet whereby the lighter fibrous stalks are carried into the conduit and the heavier stalks and extraneous substances are discarded.

12. An apparatus as described in claim 10 wherein the preliminary separating means comprising a conduit connected to the screen inlet and having an inlet end through which air is passed by the air blowing means, and means for directing the fibrous material to be separated past the inlet end of the conduit across the air stream passing therethrough comprising a chute having an open top and bottom, a side wall with an opening wall connected to the conduit inlet, and an opposite side wall having an opening aligned with said first side opening.

References Cited by the Examiner UNITED STATES PATENTS 2,333,247 11/1943 Harris et a1 24149 X 2,474,314 6/ 1949 Koehne 2415l X 3,042,976 7/1962 Barnett 1990 MERVIN STEIN, Primary Examiner.

P. C. FAW, Assistant Examiner.

Claims

1. AN APPARATUS FOR PROCESSING CRUSHED FIBROUS STALKS CONTAINING PITH TO SEPARATE THE PITH AND FIBERS COMPRISING (A) A ROTOR HAVING LATERALLY EXTENDING HAMMERS, (B) A SCREENING ELEMENT SUROUNDING THE ROTOR, AND HAVING AN OPEN INLET AND OUTLET ENDS, AND (C) A CASING MEANS SURROUNDING THE SCREENING ELEMENT FOR DIRECTING AIR AROUND THE OUTER SURFACE OF THE SCREENING ELEMENT AND HAVING OPPOSED, SPACED APART WALLS TERMINATING AT A SURFACE OF THE SCREENING ELEMENT.