US2574106A - Extractor with discharge mechanism - Google Patents

Description

Nov. 6, 195.1 J. L. JONES, JR 2,574,105

EXTRACTOR WITH DISCHARGE MECHANISM Filed May 7, 1947 3| JAMES L.J'ONES,JR.

,' INVENTDR.

35 BY ,W PM

AGENT Patented Nov. 6, 1951 UNITED STATES EXTRACTOR WITH DISCHARGE MECHANISM James L. Jones, Jr., West Point, Miss., assig-nor to'Hercules Powder Company, Wilmington, Del., a corporation of Delaware nlica on Ma 7 erial No M6519 6 Claims. (01. 23-267) This invention relates to improvements inextraction or leaching apparatuses'and to a'method of discharging leached residue therefrom. More particularly, it relates to animproved apparatus for the extraction of resin from wood chips and to the process of discharging the spent wood chips therefrom. v

It is common practice in the art of extracting rosin, pine oil, and turpentine from pine stump Wood to shred or chip the Wood and to load the resulting fragmentary'material or chips into an elongated cylindrical tank through a porthole in the top thereof, to extract said material with a volatile solvent, and, after withdrawing the extract and steaming off the residual solvent from said material, to discharge the resulting extracted material manually by rake and pitch fork through an unloading- 'porthole near the lower end of said tank. Since'the extracted-material or so-called spent chips are steaming hot,

pleasant and time consuming.

the removal of spent chips in this manner is'un It is the object of; this invention to p rovide an improved apparatus for extraction of pine wood chips. It is a particular object to provide an extraction apparatus from which the spent wood chips may be readily discharged. Another object is to provide means whereby an extrac-j tion apparatus can be rapidly unloaded and put in condition for reloading with fresh wood chips.- A still further "object is to provide means for removal of hot spent wood chips from extractors toistorage bins without intermediatehandling. Other objects and advantages of the invention will appear hereinafter. V

Now in accordance with this invention, there is provided an apparatus for extraction of hogged, shredded, or chipped pine stump wood which comprises a tank with openings for loading with chips and extraction solvents, a discharge orifice such as a porthole in the top of said tank,

aforaminous false bottom within said tank;

means for admitting steam into the lower zone of the tank above the false bottom and in juxtaposition thereto, a'flue within said tank adapted to communicate with the discharge orifice and means for moving the flue into and out of communication with said, discharge orifice.

In discharging a charge of wood chips from the apparatus of :this invention; steam is ad mitted into the lower part oi'the,itankf 'and-permitted to permeate the wood'chips and to raise the mass of wood chips gradually. to' thef upper-l m a of ai nk an t9 e i ed?" 1% s b stantial proportion of the Wood chip's'through 2 the discharge orifice in the top of the tank. After a predetermined time the flue within the tankis then moved into communicating relationship with said discharge orifice and the residual wood chips are blown out with a current of steamflowing from the lower part of said tank and out through said flue. To facilitate egress of the chip mass, steam may also be introduced intothe chip mass in the upper part of said tank.-

Hav-ing new indicated in a general waythe Th'eextraction-tank I9 is a pressure-resistant vessel preferablycylindrical in shape and"ver-' tically disposed having a discharge orifice or por-thole H in the top thereof adapted to be sealed with a cover .(not shown) when used in the extraction process and adapted to be fitted with a conduit I 2 leading to a chip collector 13 when beingunloaded or discharged. The upper part of the tank is fitted with one or more parts It; [5, and 15 connected with conduit meansfor the admission of steamthrough valve H from a steam source. The lower end of the tank is fitted with a foraminous false bottom [-8- which acts as a support for wood chips. The lower portion of the tank is preferably fitted with a manhole I9 fitted with a detachable cover for access to the inside of the tank above said false bottom. The bottom of the tank below the false bottom is fitted with port '20 for allowing passage of steam Port 20 maybe used both as apo'rt' for admitting extraction solvent during the extraction operation and for admitting high Pros sure steam during the unloading operation, valve 21 being agate valve connecting with a high pressure steamsource and valve 22 being a valve fi ue""23"having a diameter preferably substan tially about the same size as that of porthole H and having fins or centering members 24 andadapted to benoved-into communication with said porthole 'H, thereby forming a path from the lower portion of said tank through the porthole and adapted to be moved out of communication with said porthole. The fins 24 are preferably steel plates welded to said flue in sets of at least three, equally spaced around the circumference of the flue and perpendicular therewith. The fins are adjusted so that they do not quite touch the tank wall. There is preferably an upper set of three fins and a lower set of three fins, disposed in staggered relationship to each other. At least the upper set of three fins is provided with contact members such as steel roller guides 25 for reducing friction when in contact with the vertical walls of the tank.

Flue 23 is integrally connected through steel supporting struts 26 within said flue to a steel shaft 21 which extends through the false bottom l8 and through a packing gland in the bottom of the tank to a reciprocating means.

Said reciprocating means preferably comprises a hydraulic cylinder 28 having a piston 29 integrally connected with shaft 21, the hydraulic cylinder being provided on each side of the piston with hydraulic fluid lines 30 and 3| connected with valve means 32 for selectively transmitting hydraulic pressure from hydraulic pressure main 33 against the desired side of the piston for reciprocating the same. Hydraulic fluid line 30 is preferably fitted with a three-way valve 34 for permitting removal of hydraulic fluid from the hydraulic cylinder when piston 29 is ascending.

The shaft 21 is preferably provided with an indicating means 35 adapted to cooperate with the movement of the shaft to indicate the position of the flue connected therewith in relation to said porthole. Said indicating means may in its simplest form comprise an extension member such as a rod attached to said piston and extending through a packing gland in the end wall of said hydraulic cylinder.

Outlet 3! at the top of the tank is a valved line used in the extraction process but normally closed in the extrusion process.

The operations involved in discharging a mass of spent chips from an extraction tank of the type set forth and described are best understood by a detailed description with reference to the drawing of the apparatus.

Initially the extractor is at atmospheric pressure and loaded with spent pine wood chips (60% of which initially passed through a V -inch mesh screen) from which the extractable material has been removed. ,The spent wood chips which do not entirely fill the space within the tank I due to settling are hot from a previous steaming operation whereby the residual extraction solvent was removed. The flue 23 is in the down position resting on the foraminous false bottom It and is also filled with wood chips. The porthole II is open and connected with conduit |2 for leading the extruded chips to the chip collector l3. All other ports and openings into said tank are closed. Three-way valve 34 is in the position opening the line 30 from the upper zone of hydraulic cylinder 28 to the atmosphere and four-way valve 32 is in the position opening line 3| from the lower zone of the hydraulic cylinder to the atmosphere.

7 Under the above set forth conditions-operations are timed as follows: Steam is admitted through ports I4, I5, and I6 in small volume into the chip mass in the-upper zone of the extraction tank. Valve 2| is then opened to admit steam into the tank at the base of the chip mass.

The steam thus admitted permeates the chip mass. As pressure increases below the chip mass, the mass of wood chips with flue embedded therein rises as indicated by discharge of fluid through valve 34 and the drawing in of air through valve 32 and line 36 and the rising of the flue position indicator 35. The admission of steam is continued until the flue reaches a position short of communication with said porthole I I, so that it does not obstruct egress of chips through the discharge orifice. The flue is then stopped in this position before it communicates with the porthole by turning four-way valve 32 into neutral position isolating lines 30, 3|, and 33, and by turning three-way valve 34 to close the outlet to the atmophere and to open line 30 to the upper zone of said hydraulic cylinder. The chip mass continues moving past the flue and the chips become permeated with steam entering the ports l4, I5, and Hi and are made less dense thereby so that they appear to be in the form of a very concentrated suspension of wood chips in steam. This suspension of wood chips in steam is then extruded through the porthole H in a sudden flow and one-half to two-thirds 01' the chips in the tank are forced out in this manner in a very short time with very little steam loss.- The steam pressure at the base of the chip mass required to accomplish this extrusion may be as low as about 14 to 16 pounds per square inch. The extrusion is quickly completed and ends with a sudden drop in steam pressure to near atmospheric pressure. Valve 2| is then quickly opened wide to allow a large volume of steam to flow through the tank from the bottom out the porthole At the same time the flow of steam through ports |4, l5, and H5 at the upper part of said tank is stopped. A substantial part of the residual wood chips are blown out with the large volume of steam flowing through the tank. The duration of the steam blowing is of very short duration since the chips are carried out very quickly with a short blast. Ordinarily the blowing lasts only the time required to move the flue into communication with porthole so as to provide. a narrower path for the passage of chips and steam from the lower part of the tank. The flue is raised into a position communicating with the porthole by turning four-way valve 32 so as to connect line 33 with line 3| and line 30 with exhaust line 36, whereby fluid under pressure from the hydraulic main 33 flows into the lower zone of said hydraulic cylinder, thereby raising the flue. When the position of communication between the flue and the porthole is reached as indicated by indicating means 35, the flue is locked in this position by turning valve 32 to the neutral position. The flue in this new position provides a new path for the chips, the path being reversed from a flow up around the flue to a flow up through the flue. The chips previously held in suspension by the current of steam fall down the annular space between the flue and the tank walls and are swept into the bottom opening of the flue by the Venturi action of the steam and out through the porthole The volume of steam per minute required to remove the residual chips depends upon the dimensions of the apparatus and is readily calculated from data well known to those skilled in the pneumatic conveying art.

When the discharging of the tank is complete, the flow of steam is stopped and the flue is loweredto its original position by means of the hydraulic cylinder using hydraulic pressure maid in the lowering operation, if necessary. The conduit [2 is then removed and the tank is ready to be reloaded with fresh chips to be extracted.

In the operation of raising the chip mass by the application of steam pressure from below, it is preferable to allow the embedded flue to rise at the same time so as to reduce the steam pressure required to overcome the resistance to the movement of the chip mass. If desired. however, the flue may be locked in a position out of communication with porthole ll during the initial stages of the extrusion since the raising of the flue with the chip mass is not essential to the process.

The fins, 24, besides serving as guides for the flue also serve as means-for breaking "up any arching chip masses. If necessary the flue may thus be raised and lowered to break up any chip masses which tend to clog the tank during the blow.

The extrusion of wood chips under pressures below about 50 pounds per square inch or preferably under pressures within the range of about to about 20 pounds per square inch "is dependent upon the conversion of the wood chips to a fluid or extrudable state. This conversion to a fluid state is accomplished by permeating the chips with steam'to moisten and thereby decrease the plasticity of the chip mass and to make the chip mass have the characteristics of an elastic fluid or of a concentrated suspension of wood chips in steam. The steam introduced at the base of the chip mass permeates the chip mass and distributes the pressure required to raise the chip mass so that packing of the mass due to compression is substantially negligible. The steam introduced into the chip mass at the top of the tank near the porthole acts further to lower the density of the chip. mass and to reduce packing tendency of the chips and to in-- crease the elasticity of the extruding mass, in the upper zone where compression is greatest as the chip mass is forced through the porthole. The introduction of steam near the porthole is a preferred operation but it is not essential to the operation since steam introduced at the base of the chip mass is sufficient to facilitate the extrusion even though pressures in the range of about 20 to about 50 pounds per square inch may be required to overcome the resistance of the more dense and less fluid chip mass at the porthole.

From the above set forth description of the method of discharging spent chips from an extractor, it will be seen that by employing alternative embodiments of the invention that the spent chips may be removed to a large extent simply by the process of extrusion without the use of the flue. In addition, the residual chips may be removed without the use of the flue but with great loss of steam by blowing large volumes of steam upwardly through the tank until substantially all of the residual chips are blown out the porthole. Moreover, the residual chips may be removed in the well-known manner of blowing or raking through an opening or manhole in the zone of the false bottom of the tank. However, the greatest improvement over the art involves a combination of the step of extruding with the step of blowing residual chips through a. flue.

While the description of this invention has been applied to extracted wood chips, it is equally well adapted to unextracted chips. Moreover,

6 where the term chips is used throughout this specification and claims, it is understood .to'inelude wood fragments obtained in various ways such as chipping, hogging, shredding, sawing, etc., and having a size not substantially greater than that used in wood pulping operations. 7

- While steam has been used throughout this specification, it is to be understood that other compressible inert gases such as air, nitrogen, waste flue gases, etc., may be used for providing the necessary extruding pressure and the necessary gas flow to carry the chips out the flue. In the case of the use of other gases, it is preferable that the spent wood chips be pliable as: when moist with hot steam. Spent chips with a moisture content of 20-40% have the desired pliability. Steam is preferable in that it ren-' ders the spent wood chips pliable and is readily available in the volumes required for the necessary blowing.

From the foregoing description of the apparatus of this invention and the manner in which it is operated, it is seen that there is provided a rapid, economical, and less laborious method of removing spent wood chips from extraction tanks which is a distinct advance in the art.

WhatI claim and desire to protect by Letters Patent is:

I. An extractor comprising an elongated cylindrical tank, a porthole in the top of the tank, conduit means adapted to admit steam into the upper part of the tank, a foraminous false bottom within the tank, conduit means adapted to admit steam into the zone below the false bottom; a flue smaller in diameter than said false bottom within the tank having a shaft integrally connected therewith, and means in cooperation with said shaft adapted to reciprocate the flue along its vertical axis betweena position wherein the flue is in communication with the porthole and a position wherein the flue is out of communication with the porthole.

' 2. An extractor comprising an elongated cylindrical tank, a porthole in the top of the tank, conduit means adapted to admit steam into the upper part of the tank, a foraminous false bottom within the tank, conduit means adapted to admit steam into the zone below the false bottom, a flue smaller in diameter than said false bottom within the tank having a shaft integrally connected therewith, means in cooperation with said shaft adapted to reciprocate the flue along its vertical axis between a position wherein the flue is in communication with the porthole and a position wherein the flue is out of communication with the porthole and adapted to lock the flue in a predetermined position.

3. An extractor comprising an elongated cylindrical tank, a porthole in the top of the tank, conduit means adapted to admit steam into the upper part of the tank, a foraminous false bottom within the tank, conduit means and valve means cooperating therewith adapted to admit steam into the zone below the false bottom, a cylindrical flue smaller in diameter than said false bottom within the tank having at least three centering members integrally connected therewith and hav ing contact members adapted to reduce friction between said centering members and the vertical walls of the tank and having a shaft integrally connected therewith, means in cooperation with said shaft adapted to reciprocate said flue along its vertical axis between a position wherein said flue is in communication withthe porthole and a position wherein the flue is out of communication with the porthole and adaptedto lock the flue in a predetermined position. a i I ,4. An extractor comprising an elongated cylindrical tank, a porthole in the top of the tank, conduit means and valve means cooperatin therewith adapted to admit steam into the upper part of the tank, a foraminous false bottom withinsaid tank, conduit means and valvemeans cooperating therewith adapted to admitsteam into the zone below the false bottom, a cylindrical flue smaller in diameter than said false bottom within the tank having at least three centerin members integrally connected therewith and having contact members adapted to reduce friction between said centering members and the vertical walls of said tank and having a shaft integrally connected with the flue, means in cooperation with said shaft adapted to reciprocate the flue along its vertical axis between a position wherein the flue is in communication with the porthole and a position wherein the flueis out of communication with the porthole and adapted to lock the flue in a predetermined position.

5. An extractor comprising an elongated cylindrical tank, a porthole in the toprof the tank, conduit means and valve means cooperating therewith adapted to admit steam into the upper part of the tank, a foraminous false bottom within the tank, conduit means and valve means cooperating therewith adapted to admit steam into the zone below the false bottom, a cylindrical flue smaller in diameter than said false bottom within the tank having at least three centering members integrally connected therewith and having contact members adapted to H 6. An extractor comprising an elongated cylin drical tank, a porthole in the top of the tank, conduit means and valve means cooperating therewith adapted to admit steam in large volume into the upper part of the tank, a foraminous false bottom within the tank, conduit means and valve means cooperating therewith adapted to admit steam into the zone below the false bottom and in juxtaposition thereto, a cylindrical flue smaller, in diameter than said false bottom within the tank adapted to reciprocate along its vertical axis, said flue having at least three centering members integrally connected therewith and having contact members adapted to reduce friction between said centering members and the vertical walls of the tank and having a shaft integrally connected with the fine and extending through the false bottom and the bottom of the tank, a hydraulic cylinder and a reciprocating piston therein adapted in cooperation with said shaft to reciprocate the flue along its vertical axis between a position wherein the flue is in communication with the porthole and a position wherein the flue is out of communication with the porthole and adapted to lock the flue in a predetermined position, and means for indicating the position of the flue in the tank.

JAMES L. JONES. JR.

REFERENCES CITED The following references are of record in th file of this patent:

UNITED STATES PATENTS

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