US2533296A - Extractor provided with means for unloading it - Google Patents

Description

Dec. 12 950 J. STUARTJL 2,533,296

EXTRACTOR PROVIDED WITH MEANS FOR UNLOADING IT Filed Aug. l5, 1947 BY M AGENT kiatenreci Een, l2, 1950 UNITED STATES PATENT OFHQE EXTRACTOR PROVIDED WITH MEANS FOR UNLOADING IT Application August 15, 1947, Serial No. 768,923

2 Claims. 1

This invention relates to improvements in extraction or leaching apparatuses and to a method of discharging leached residue therefrom. More particularly, it relates to an improved apparatus for the extraction oi rosin iro-in wood chips and to the process oi discharging the spent wood chips therefrom.

it is common practice in the art oi' 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 thereof, to extract said material with a volatile solvent, and, after withdrawing the extract steaming ofi the residual solvent from, said material, to discharge the resulting exmaterial manually hy rake and pitchfork through an unoading porthole near the lower end of the tank. Since the extracted material or so-called spent chips are steaming hot, the removal of spend chips in this manr'iery is untime consuming.

it is the object of this invention to provide an improved apparatus for extraction oi pine wood chips. it is a particular object to provide an extraction apparatus from which the spent wood chips, may he readily discharged. Another object is to provide means whereby an extraction apparatus can be rapidly unloaded and put in condition for reloading with fresh wood chips. still further object is to provide means for removal of hot spent wood chips -from ertractors to storage bins without interH mediate handling.

@ther objects and advantages of the invention will appear hereinafter.

Now in accordance with this invention, there is provided an apparatus for extraction of hogged, shredded, or chipped pine stumpwood which comprises a tank with openings for loadwith chips and extraction solvents, a dis.- charge orice such as a` porthole in the top of the tank, a close fitting slidable flue through said porthole having suhicient length toextend from the porthole to the bottom of the tank, a plurality of nozzles for admitting steam at spaced intervals from tcp to 1oottom, means for opening sai?, nozzles at each level independently, and inea-ns 'for lowering said flue tothe lower part of said tank.

ln discharging a lcharge of wood chips from the apparatus of this invention, steam is injected through the ports in the uppermost part of the tank to loosen the top layer of chips from the chip mass. The flue is lowered to the zone above the chip mass and the loosened chips are swept out by the current of steam. Steam is then injected through ports on the next lower level and the ports above are shut off. The flue is again lowered to the zone of the loosened chips and the chips are swept out through the hue. These steps are repeated until the tank is empty. Preferably the injecting of the steam at the progressively lower levels and the lower.- ing oi the flue to the preceding top of the chip mass are synchronized to provide an optimum rate of now of wood chips with the current oi steam.

Having now indicated in a general way the nature and purpose oi this invention, there ollows a more detailed description of the preferred embodiments thereof, with reference to the accompanying drawing in which:

The gure illustrates an apparatus in accordance with this invention from which spent chips can oe discharged rapidly according to the method oi this invention. The extraction tank iii is a pressure-resistant vessel preerahly cylindrical in shape and vertically disposed having a discharge oriiice or po-rthole li 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 'flue i2 leading cy means of a ilexicle conduit i3 to a chip collector le when being unloaded or discharged. The flue is adapted to fit the discharge orice closely, preferably by means of a packing gland assembly li and to be slidahle therethrough to the lower part of the tank and to he of suiiicient leng :l to extend from the discharge orifice to the lower part or the tank as indicated oy the broken line. The flue is iitted with means for raising and lowering such as a rack t3 and motor-controlled pinion il. The rack is attached to or forms part of a guide rod i8 slidably connected to a support it to aid in alignment of the flue.

The tank is iitted with a plurality of ports 29, 2i, 2l which may he noz-ales for admission of steam at spaced levels from the top to the bottom. These ports are supplied with steam through annular mains 23, 2S, 35, the main at each level being independently valved with valves 35, 3l, f1.3 connecting with a steam header lill. vThe bottom of the tank is fitted with a valve do for allowing passage of steam through port 45 from steam header Alli. Port llt is also used during the extraction operation for admitting and withdrawing extraction Solvent through valve 4l.

Within the tank is a foraminous false bottom d8 for supporting the chip mass, and in the side of the tank in the zone above the false bottom there is a manhole tted with a detachable cover 49 for allowing access to the inside of the tank.

The steam ports may be arranged in any of several ways other than that shown. In the drawing the ports are arranged partly in vertical planes and partly in staggered planes. They may also be arranged all in vertical planes or advantageously all in staggered planes or in various combinations. A zigzag arrangement minimizes any tendency toward channeling. The ports may be provided with nozzles or other suitable means for directing the steam jets. The steam in this way may be directed either centrically or tangentially. It is preferred that the steam be directed tangentially so as to give a longer effective steam lpath. In any arrangement of the ports, it is preferable that the ports be directed away from the path of the steam from an opposite port to avoid channeling due to combined action of the steam jets. While the steam jets may be directedly upwardly, downwardly, or horizontally, it is preferred that they be directed upwardly at at least a slight angle from the horizontal.

While only one valve is shown for controlling the flow of steam at each level, there are further advantages in having each port on the level provided with individual valves.

rf'he 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 1Ag-inch mesh screen) from which the extractable material has been removed. The spent wood chips which do not entirely ll the space within the tank lil due to settling are hot from a previous steaming operation whereby the residual extraction solvent was removed. The top of the chip mass is in the region of the uppermost level of port 2G. Porthole l has been tted with packing gland assembly i through which flue l2 is slidably positions-d. Valves 3d, through Li3 inclusive, 45, and 'i are all closed.

Under the above set forth initial conditions, valve 35 is opened and steam is admitted `preferably under high velocity into the upper part of the tank. The chips on the top of the chip mass are loosened by the force of the steam and are carried out the flue to the chip collector Hi. When the low of the chips through the flue begins to diminish, valve 3l is opened and Valve 35 is closed and the flue l2 is simultaneously lowered to the new level of the chip mass. These operations are continued stepwise by operating the valves at the successively lower levels and lowering the flue to the successively lower regions until the lowest Valve 3 has been opened. The remaining chips are then loosened by opening valve i5 to admit steam by way of port i6 through the foraminous false bottom 8. The loosened chips are completely swept out the ue with the current of steam. When all of the chips have been thus removed valves 43 and 45 are closed, the iiue i2 is withdrawn7 and the packing gland assembly l5 is removed. The extraction tank is then ready for loading with fresh chips to be extracted.

Under actual operating conditions it sometimes happens that channeling of the steam through the chip mass occurs at the site of one or more of the ports. Under such circumstances it is desirable that the various ports at that level be tted with individual valves to prevent loss of steam due to channeling. However, without individual valves it is possible to overcome the disadvantageous eects of channeling by opening the valve at the next lower level to aid in loosening the chip mass. Channeling may also be prevented to a large degree by operating the valves in such a manner as to provide blasts of steam of short duration. Channeling is less likely to occur when the steam ports are placed in diagonal or staggered arrangement and when the steam jets are directed tangentially so as to provide a swirling ow. The swirling flow may be either clockwise er counterclockwise but is preferably alternated by the Successive levels. Thus it is seen that with various arrangements of the steam ports some nexi'oility in the operation, especially as to the order of opening and closing of valves, is desired. For similar reasons, nexibility as to the rate of lowering the flue is also desired. The optimum position for the flue in respect to the chip mass is only determined by experiment with the particular charge being unloaded. However, this position has been found to be usually only a few inches above the top of the chi-p mass.

The flue may be raised and lowered by any suitable means. While it may have sufficient weight to abe lowered by gravity, and while the pressure within the tank may not be so great as to force the flue out of the tank, it has been found desirable to have under control both the raising and the lowering of the flue at all times. A rack and pinion arrangement connected through a speed reducing gear box 53 with a reversible motor 5| for driving means has been found to be particularly suitable. This driving mechanism as well as the support I9 for the guide rod i8 which aids in alignment of the ue is suitably built on an elevated platform or on an upper floor of the extraction house.

While the description of this invention has been applied to extracted wood chips, it is equally well adapted to unextracted chips. Moreover, where the term chips is used throughout this specication and claims it is understood to include wood fragments obtained in various sizes such as chipping, hogging, shredding, sawing, etc., and having a size not substantially greater than that used in wood pulping operations.

While steam has been used throughout this specication, it is understood that other inert gases such as air, nitrogen, wast/e :due gases, etc., may be used for providing the necessary gas flow to carry the chips out the nue.

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 chips from extraction tanks and is thus a distinct advance in the art.

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

1. An extractor comprising a tank, a porthole in the top of the tank, a close fitting flu-e slidably disposed in said porthole, said i'lue having sufficient length to extend from the porthole to the bottom of the tank, a plurality of steam ports at spaced levels from top to bottom of said tank, means for opening and closing said ports at each level independently, and means for lowering said iue to the lower part of the tank.

2. An extractor comprising an elongated cylindrical tank, a porthole in the top of the tank, a packing gland in said porthole and a close fitting nue slidably positioned in said packing gland, said flue having sufcient length to extend from the porthole to the bottom of the tank, a plurality of steam ports at spaced levels from top to bottom of said tank, means for opening and closing said ports at each level independently and progressively from top to bottom, and means for lowering said flue progressivelyr to the lower part of said tank.

JOSEPH STUART, II.

6 REFERENCES CITED l The following references are of record in the ille of this patent:

UNTLTED STATES PATENTS

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