US2835292A

US2835292A - Method of processing raw wood

Info

Publication number: US2835292A
Application number: US444787A
Authority: US
Inventors: Julius F T Berliner
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-07-21
Filing date: 1954-07-21
Publication date: 1958-05-20
Anticipated expiration: 1975-05-20

Description

y 1958 J. F. T. BERLINER METHOD OF PROCESSING RAW WOOD Filed July 21, 1954 iZZ/QZZZEOZ" (fa/245 Ff fierZz'zzer United States Patent METHOD OF PROCESSINGRAW WOOD Julius F. T. Berliner, Chicago, Ill.

Application July 21, 1954, Serial No. 444,787

Claims. (Cl. 144-309) This invention relates to a method of processing raw wood, and more particularly to a method adapted to the preparation of the wood of shrubs such as those found in desert regions, for use in the production of hardboard and for the recovery of lay-products from the wood.

In the development of a new fiber-board material and a process of making such material from certain desert shrubs, including the creosote bush, as described in detail in my co-pending application Serial No. 442,637 filed July 12, 1954, for Fiber Board and Process of Making Same From Desert Shrubs, it was found desirable to remove as much as possible of the barkfrom the wood, because the presence of such bark tends to effect the formation of a mud during the processing of the wood fibers, which mud materially retards the rate of formation of the fibrous mat in the process of forming the material into a sheet, and also darkens the color of the resultant board product. As initially cut, the shrubs are severed from their root growth close to the ground. As an early step in the preparation of the wood for :use, it is chopped or cut into pieces of various sizes and shapes ranging generally from 2 inches to 5 inches in length and having the shapes and lateral dimensions of normal growth.

The creosote bush, which has been found to be very satisfactory in characteristics for adaptation to the production of hardboard, has relatively thin bark which clings tenaceously to the wood, and which is brittle and has little or no fiber structure. The characteristics of v the bark and the irregularity of the sizes and shapes of the wood pieces, in addition to the generally small diameters of the wood pieces, all contribute to the difficulty of the problem of elfecting the removal of a satisfactory proportion of the bark from the wood. It is natural, of course, that since the wood without its bark is a usable portion of the plant, for the production of board, the waste of the wood in the process of removing the bark is to be minimized. Furthermore, it is desirable that the process of effecting removal of the bark shall leave both the wood and the bark in separable and recoverable condition without necessitating the drying of either or both, or other such preparatory operations.

Washing and floatation of cooked bark from digested wood chips proved to be unsatisfactory methods of separating the bark from the wood fibers and their constituents, since the constituents of the wood fiber are usable with the fibers in my process for the production of board. Also, wet tumbling of the wood chips in a pebble mill was found to result in an undesirable high loss of the wood fibers. it being readily understandable that the production of fiber-board in quantity necessitates the processing of very large volumes of wood chips of the type to which reference has been made, it is the general object of this invention to provide a method for effecting the removal of at least a large proportion of the bark from irregularly shaped and relatively small pieces of the wood of the desert shrub, such as the creosote bush, and for elfecting the separation of the removed bark particles from the wood pieces.

My invention has for another object the provision of a method for effecting the removal of a large proportion of the bark from pieces of creosote bush wood and the like without loss of an appreciable amount of wood fibers or the natural constituents of the Wood.

Another object of my invention compre-hends the'pi o vision of a method of removing bark from the wood of desert shrubs, which method leaves both the wood and the bark inseparable and recoverable conditions.

As another object this invention has within its purview the provision of a method of efi'ecting the removal of the bark from large quantities of relatively small and irregularly shaped pieces of the wood of the creosote bush in a manner which is practically continuous in its operation.

Other objects and advantages of the invention will be apparent from the following description and'the accompanying drawings in which similar characters of reference indicate similar parts throughout the several views.

Referring to the singlesheet of drawings,

Fig. 1 is a diagrammatic view depicting apparatus adapted to use in carrying out the steps of my method as disclosed herein; and

Fig. 2 is a fragmentary front elevational view of a detail of a part of the apparatus depicted in Fig. 1.

In the exemplary embodiment of my method for processing raw wood which is disclosed herein for illustrative purposes, wood of a desert shrub, such as the creosote bush found in desert regions of the southwestern United .States,.is gathered by being out of? near the surface of the ground. For convenience in handling, hauling and storage, a portable machine is utilized for chopping the Wood of the cut shrubs into pieces which are preferably from about 2 to 3 inches in length. Since practically all of the wood of the creosote bush is usable for the production of hardboard products, the cut portions or pieces of the stems and branches vary from about 1 inches to A of an inch in diameter shapes. The Wood pieces which are thus gathered from the place of growth of the shrubs are hauled to a suitable place near the mill where they are to be: utilized, and are placed on a stockpile which, in the drawing, is indicated at 10. From the stockpile 10, the wood pieces are carried on a conveyor 12 and fed into a hopper 13 which comprises the entrance to a debarking machine, indicated generally by the reference numeral 14. From an outlet opening 15 of the debarking machine, the pieces of wood from which the bark has been substantially removed and the finely divided particles of bark are discharged onto a screen 16 for separation of the bark particles from the wood pieces. The bark particles pass through the screen and into a hopper 17, from which they are discharged through a conduit 18. The wood pieces'p'ass from the screen 16 into a hopper 19 and are conveyed therefrom to a digester or place of treatment through a conduit 20.

It may be understood that since the bark of thecre'osote bush has little or no fiber structure and isremoved, in my process, in a dry state, by mechanical action which leaves the wood pieces intact, the bark particles may be separated from the wood pieces by the action of a blower, instead of the screen separator depicted in the drawing. In either instance, the dry wood pieces and the dry bark particles are separated and separately gathered for further treatment, as desired, and are in a dry state, ready for use, and there are no problems arising from the dissolving of soluble constituents of either the bark or the wood, which constituents are desirably left in the wood and are of irregular and bark for the further treatment. For effecting the removal of at least a very large proportion of the bark from the wood pieces without appreciable loss of wood and by mechanical method which does not require washing or water separation, I utilize a disk type mill 22 having a housing 23, which housing encloses relatively movable plates 24 and 25 which are in spaced, opposed and face-to-face relationship with one another, and at least one of which is driven through a shaft 26 by a prime mover such as an electric motor 27. In the disclosed debarking machine, the plate 25 is supported from the motor shaft 26 by a disk 28, and is thereby driven at relatively high speed with reference to the plate 24; the latter plate'being stationary and secured to the housing 23.

Wood pieces having the bark thereon and fed into the hopper 13 flow into the mid-portion of one end of the housing 23' and are moved outwardly between the op posed and spaced surfaces of the plates 24 and 25 by both frictional and centrifugal forces. As depicted in Fig. 2, the opposed faces of the plates 24 and 25 have a multiplicity of teeth 29 projecting therefrom to effectively roughen the operating surfaces of the plates, whereby those plates not only provide impact and a beating action on the wood pieces, but also cause the wood pieces to be beat and battered together. The resultant flexure of the wood pieces and the impacts encountered by the pieces, as well as the friction of the pieces between themselves and against the disks cause the bark to be broken into particles and separated from the Wood, after which the wood pieces and bark are finally thrown outwardly against the interior of the housing 23 for relatively heavy impact against that housing to further insure the removal of the bark from the wood. The separated bark and the debarked wood pieces flow outwardly by gravity through the discharge opening in the housing.

Since centrifugal force and impact are utilized for the loosening and separating of the bark from the wood, the rotary disk of my debarking machine is driven at relatively high speed. A speed of 3600 R. P. M. has been found to be satisfactory. For effecting the debarking of wood pieces of the sizes referred to, it has been found that a separation of between /2 inch and 1% inch is between the surfaces of the plates 24 and is satisfactory. The wider spacing leaves some bark on the wood and increases the speed of movement of the wood pieces through the debarking machine. It also results in less loss of wood as a result of the grinding action which occurs in the operation. An average spacing of from inch to A; inch accomplishes very satisfactory results.

From the foregoing description, it may be understood that my disclosed process of preparing raw wood of desert shrubs, such as the creosote bush, for use in the production of hardboard products and the like includes the steps of severing the wood portions of the shrubs into relatively small pieces, removing the bark from the wood pieces without appreciable loss of wood fiber by mechanical means utilizing frictional and impact forces to flex, tumble and batter the wood pieces so as to loosen and remove the bark therefrom, and then separating the wood pieces from which the bark has been removed from the particles of bark.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. The process of preparing the wood of a desert shrub for use in the production of a hardboard product, which process comprises the steps of severing the natural woody parts of the shrub into pieces of natural lateral shape and of a few inches in length, feeding the severed pieces into the midregion of a disc type mill having at least one revolving disc driven at a speed such that the pieces are thrown outwardly by centrifugal force so as to be battered together while being tumbled and contacted with impact force by the disc, whereby the bark is broken into particles and removed from the wood.

2. The process of preparing the wood of a desert shrub for use in the production of a hardboard product, which process comprises the steps of forcefully battering together and abrading relatively small pieces of the wood in a normally dry state between relatively moving plates having rough surfaces in spaced relationship to one another and having a speed of relative motion sufiicient to shatter and loosen the bark by impact, thereby to effect removal of a large proportion of the bark from the wood.

3. The process of preparing the wood of a desert shrub for use in the production of a hardboard product, which process comprises the steps of forcefully battering together and abrading relatively small pieces of the wood in a normally dry state between plates having rough surfaces in spaced relationship to one another and which move relative to one another at high speed, thus affording impact sufficient to shatter and loosen the bark, thereby to effect removal of a large portion of the bark from the wood, the said battering together and abrading of the wood pieces constituting a continuing operation as a result of a flow of the wood pieces between the relatively moving plates.

4. The process of preparing the wood of a desert shrub for use in the production of a hardboard product, Which process comprises the steps of severing the natural woody parts of the shrub into relatively short pieces of natural diameters, and effecting removal of a lar e portion of the bark from the wood pieces by mechanical and forccful battering of the pieces together at high speed to provide impact sufficient to shatter and loosen the bark, and abrading the pieces to remove the shattered and loosened bark while the wood is in a normally dry state.

5. The process of preparing the wood of a desert shrub for use in the production of a hardboard product by the removal of bark therefrom, which process comprises the steps of forcefully battering together and abrading relatively small pieces of the wood in a normally dry state between metal discs in spaced and opposed relationship and moving relative to one another at a high speed which is sufficient to provide impact which shatters and loosens said bark.

References Cited in the file of this patent UNITED STATES PATENTS 632,979 Wolfe Sept. 12, 1899 1,120,631 Schenck Dec. 8, 1914 1,247,526 Ginettley Nov. 20, 1917 1,877,517 Macartney Sept. 13, 1932 2,558,574 Martin et a1. June 26, 1951 2,596,015 Dunwoody May 6, 1952