CA1074178A - Modular split screen hydro-extractor - Google Patents

Abstract

MODULAR SPLIT SCREEN HYDRO-EXTRACTOR

ABSTRACT OF THE DISCLOSURE
In a hydro-extractor, a screw is disposed with an outer concentric cylindrical sieve. The sieve is formed of sections placed lengthwise of the screw, with each section capable of having the same or different size holes so that the extractor captures solids both large and small in a controlled manner and will dewater faster or slower with various combinations of sieve sections. Where a sieve section contains smaller size holes of higher density per unit area and is constructed of relatively thin gauge material, an outer back-up screen of thicker gauge material with large holes is utilized in order to support the thinner screen and cooperate in withstanding the pressures generated during dewatering. Therefore, modu-lation of the sieve sections may be accomplished both vertical-ly and horizontally.

Description

sA_KGROUND OF Tl-IE INVENTCON
This invention relates generally to devices for extract-ing water and other li~uids from liquid impregnated materlals, such as waste and pulp, and more particularly, to such a unit in the form of a vertical helical screw undergoing relative rotation with respect to a surrounding drainage screen.
The device which is the subject of this invention finds particular use with a waste disposal apparatus or system wherein upon treatment of the waste material, means must be provided for - separating the solids and the li~uids from within a slurry. This waste disposal system in general, may include a pulper haviny a tank containi.ng the waste materiaI, fibrous material, garbage and other disposable waste in the presence of a high percentage of watex, all being subjected to the disintegrating action of a rotatable impeller having suitable material disintegrating cutters.
(See commonly assigned U.S. Patents 2,729,146; 3,164,329; 3,589, 800; 3,620,4i60 and 3,885,745.) In apparatus of this type there is associated with the tan~ discharge, a means for delivering the water-laden disintegrated material to a liquid extracting device often referred to as a 3a :

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hydro~extra,ctor .in which a helical screw is rnadc to underyo rotation with.in a cylindrical sieve. l\he hydro-extxactor separa1 es the solids from the liquids by withdrawing the liquid from the material received from the pulper or selected disintegrating or mascerating unit. In U.S. Patent 3,39~,649, having a common assiynee with this application, there is disclosed such a hydro-extractor in which there is a cylindrical ~creen or hollow cylindrical sieve surrounding the major portion of the screw.
SUMMARY OF ~HE INVENTIO~
. _ _ The hydro-extractor of the present invention is an im-prove~.ent over the apparatus of' Patent No~ 3,394,649 a.s a ~ result of the attaimnent of closer control over solids captured : and water extracted.
It is an object of the invention to provide a hydro~
extractor of the type described above in ~hich the sieve is ~: formed of a plurality of sections placed lengthwis* each section having different size holes. It thus ~ill ~e possible to employ ~; combinations of two or more of such sections to control capture o~ the solids and to obtain faster or slcwer water extraction depending on the size of the holes in each. section~ Where a selected section conta.ins holas of reduced siæeof high density .~ , per unit area and is fabricated of relatively thin gauge , ~ material, an outer back-up screen with larger holes supports : the thinner screen to withstand the high pressures encountered 5~ during dewa~-ring~

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It is a further object to provide appaxatus of the ~ore-going type which i5 economically manufac-tured,is efficient, well suited for its intended purpose and capable of sieve section modulation hoth vertically and horizontally to alter the operating paramekers in response to the waste material being handled.
BRIEF DESCRIPTIO~ OF TEIE ~RA~ GS
Other objects and advantages will become apparent from the follo~ing description which is to be taken in conjunction with khe accompanying drawings, in which:
Figure 1 is an elevational view of a liquid extracting device em~odying the present invention with portions thereo~
¦ cut away or removed to disclose certain details of construction;
~igure 2 is a sectional view taken along tha line 2-2 ,; of Figure l;
Figure 3 is a sectional view taken along the line 3-3 of Figure 2;
Figure 4 is a sectional view taken along the line 4-4 of Figure 2;and ~ Figure 5 is an en}arged sectional view showing a part o~
i~ ~ a supported sie~e section-.. , '''' " ''' "
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DESCRIPTION OF T~l~ P F __~D ~MII DIM~NT
~eferring to the drawings, there is shown in Figure 1 a liquid extracting de~ice 10 having a shell consisting o~
vertically extending members 11 and 12 and end members 13 and 14 at either end. Affixed ko the end members 13 and 14 are brackets or baffles 15 and 16 having openinys through which a screw shat 17 passes. A plate 18 provided with a baffle 19 A with an opening through which passes a ~ul~L~ e~ tube 20, an~ a plate 21 serve to complete the shell for the device.
The screw 22 o~ the hyro-e~tractor consists of a c~lindri cal screw shaft 17 having flights 23 providing an inclinad sur-fac~ in the form of a helix or screw surrounding and attached to the shaft. A cylindrical screen or hollow cylindrical sieve 24 surrounds the major portion of screw 22 in the zone between the baffles 15 and 16. one end of shaft 17 is supported in end bearing support 25 and the other end of the shaft is sup-ported in end bearing support 26. The end bearing support 25 is part of a cap 27 a~fixed to the end member 13. The end bearing support 26 is spaced from the end mem~er 14 and has cover plates 28 on the top and two sides to provide a pulp ;~ ~ diecharge chamber or zone 29~ ~he material from which water has been ext:racted is fed by the screw into this chamber and then out~o~ tha open bottom of the chamber.

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iO'741'-~8 Means not 9hown are pro~ided for rotating th2 screw 22 at the proper speed.
Referr.i.ng to Figures 2, 3 and 4, it ~ill be seen that the cylindrical screen 24 is made up of a plurality of sections bolted tog~ther at ~heir ends to orm the long screen 24.
Figure 2 shows ~wo sections 24A and 24B having the same or different solids capture and water extract.ion characteristics held together at their ends by brackets or ~af~les 30 and 31.
Such brackets or ~affles 30 and 31 are similar to the brackets or baffles 15 and 16 at the opposite ends of such sections 24A
and 24B. If necessary three or moxe sections can be secured together in the same manner to ~orm the cylindrical screen 24 with each section having dif~erent or similar solids capture '.
and water extraction characteristics.
In a particular application of the present invention, it was pre~erred that section 24A have relatively high solids caI ~_ ture characteristics. r~wards this end, .relatively small holes are formed in section parts 24A' and in all instances of ;~ screen manufacture it is preferxed to optimize hole density, . 20 that is have as many holes of the selected size formed in tha-screen part; and in order to economically form the screen par~s with t:he selected hole .size, flat sheets o~ metal have the holes initially punched therein and thereafter the sheets '.
~are formed into the illustrated shape~ The size of hole i : I~
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determln~3s the gauge of metal se1.~3cted or punching. In the stated particulax applicat.ion, the hole size was .032"
but smaller size holes, as small as .02" are contemplated.
Furthermore thin gauge metal for the small hole sizes is pre-ferred because with thicker sheets and small diameter holes, there would be danger of the srnall holes with increased depth to clog with solids. However, when utilizing thin gauge saction parts 24A', it is imperative to utilize back-up section parts or halves 24A" for support to enable parts 24A' to with-stand the pressures encountered during dewatering. In the discussed application, the parts 24A" had ~25" holes.
Fiyures 3 and 5 show that the section 24A made up o~ parts or halves 24~', 24A" are secured together along their length-wise edges.
In the stated application section 24B is designed to effecti~ely dewater the solids captured by section 24A. There-:~ fore, the hole size is larger; and in this connection it has been found that with hole s.izes and sheet gauges of .062" and larger, no back-up or support is re~uired. Figure 4 shows the section 24B ~ade up of two screens 24~' which are formed mto two half cy~inders secured together along their lengthwise edges.
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10'7~1'7t3 Irhus, merely for purposes of i.llustration, th~ first section parts 2~A might be of 26 yauge an~ hav~ .032" holes and back~up parts 24~" of 14 gauge and wi~h .25" holes, the section 2~B might have .062l' or .093" holes. If a third sec-tion were used the second section might have .062" holes and the third section .093" holes. Although the open a.rea on hole density may be varied it is preferred that the maxi.mum number of holes be made :in each secti.on. For example, for sections having holes .032" in di.ameter arld of su~stantially the ind:i-la cated gauge, 400 punched holes per squre inch could ~e utilized; and for secti.ons having holes .25" in diclmeter and the indicated gauge, the open area equalled 5~/O. In this manner, deperlding on the application, the extractor will capture solids and dewater faster or slower by using the proper combinations of screens.
Since the operation of hydro-extractors is well known tsee for example U.SO Patent ~o. 3,394,64g) it is not neces~
sary to describe such operation. It will be apparent that ~he :~ ~bility to select and combine screen sectlons with different size holes provides an opportunity for capture and drainaye of waste material not found in the hydro-extractors o~ the prior aF

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r~hus among others, the se~eral aforenoted o~jects and advantagPs a.re most effecti~ely attained. Althouyh somewhat preferred embod:iments of the invention have been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.

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Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In the hydro-extractor of the type designed to re-ceive a mixture of liquid and solids and to dewater the mixture to form a substantially solid dry plug of material therefrom having in combination a shell, a shaft within said shell, a helical screw formed on a portion of said shaft, inlet means for introducing said mixture at one end of said screw, a cylindrical sieve sur-rounding said screw and concentric with said shaft, a discharge space at the other end of said screw, and means for rotating said screw within said sieve to form and move said plug axially toward said discharge space, the improvement comprising: a plurality of cylindrical sieve sections placed lengthwise to form said cylind-rical sieve; means for securing one of said cylindrical sieve sec-tions adjacent the inlet means; means for securing another of said cylindrical sieve sections adjacent the discharge space; the sec-tion adjacent the inlet means being of thin guage material having holes of relatively small size to increase the capture of solids of the mixture, the ratio of the thickness of the thin guage mat-erial to the size of the relatively small holes being such that clogging of said small holes is substantially prevented; the thin guage material being so constructed as to be unable to withstand the pressures of dewatering; an outer cylindrical support member supporting the section adjacent the inlet means so as to withstand the pressures during dewatering, said support member having holes of relatively larger size than those in the thin guage material;
and the section adjacent the discharge space having holes of larger size than those in the section adjacent the inlet means to increase the dewatering of the captured solids.

2. The invention in accordance with claim 1, wherein means are provided for modulating said sieve sections to alter the operating parameters in response to the mixture being handled.

3. The invention in accordance with claim 2, wherein said means for modulating said sieve sections includes brackets at the ends of said sections.

4. The invention in accordance with claim 2, wherein said means for modulating said sieve sections includes baffles at the end of said sections.

5. The invention in accordance with claim 1 wherein the section adjacent the inlet means has approximately 0.032" holes.

6. The invention in accordance with claim 5 wherein the sieve section adjacent the inlet means has about 400 punched holes per square inch.

7. The invention in accordance with claim 1, wherein the section adjacent the discharge space has approximately 0.062" holes.

8. The invention in accordance with claim 1, wherein the section adjacent the discharge space has approximately 0.093" holes.