US3527158A - Positive displacement press - Google Patents

Description

Q United States Patent mi 3,527,158

[72] Inventor William 0. Young 3,279,357 /1966 Farmer 100/1 16X Sugar City, Colorado 81076 [21] App1.No. 738,514 FOREIGN PATENTS [22] Filed June 20, 1968 Patented Sept. 8, 1970 273,294 12/1927 'Great Britain 100/116 [54] POSITIVE DISPLACEMENT PRESS 10 Claims, 5 Drawing Figs.

[52] U.S.Cl 100/117, 100/145 [51] Int. Cl B30b 9/12, B30b 9/18 Field of Search /1 10,

[56] References Cited UNITED STATES PATENTS 433,691 8/1890 Morrell 100/145 1,299,524 4/1919 wettenbl'uch 100/1 17X Primary Examiner- Peter Feldman Atmrney--Sheridan and Ross ABSTRACT: Press for separating liquid from the pulp of vegetable matter which employs a movable screen surrounding a helical vane or screw type rotor, the screen being in the form of a helically twisted surface and gyrating in an orbit around the rotor axis to provide constant clearance between all points on the outer periphery of the vanes and corresponding laterally adjacent points on the inner periphery of the screen.

Patented Sept. 8, 1970 $527,158

. ,so 74 IN W 72 44 r} [H O '8 7O 7s 78 a -P 32 34 LE- 5 20 f 22 INVENTOR. g l\\\\ WILLIAM o. YOUNG ATTORNEYS POSJI'IIVE DISPLACEMENT PRESS BACI IGROUND OF THE INVENTION In the art of separating juices from vegetable pulp, it has been common practice to employ dewatering presses, which in various manner, produce a squeezing action on the vegeta' ble matter, separating the juices from the pulp. The juices are then suitably processed for human consumption or otherwise processed into solids such as sugar, and the pulp processed for various other purposes, exemplary of which is animal consumption. As will be apparent, any juice remaining in the pulp represents a loss in the human consumable product; also, particulariy where the pulp is processed to a final dry product, a heat loss in evaporating any remaining water in the pulp.

Various presses have been employed for this purpose, among which is the well-known screw press, comprising a rotor, in the form of a screw, rotating within a surrounding screen and between which the material is conveyed and compacted, the juices being delivered through the screen and the pulp being delivered from one end of the rotor. It is well recognized that as dewatering proceeds along the length of the rotor and the material thus loses liquid content, increasing squeezing pressure is required to extract the diminishing liquid content. It has accordingly been the practice to continuously reduce the transverse cross-sectional area between the rotor and screen, in their longitudinal directions, to thereby continuously squeeze the material into progressively smaller volumes. Also, a final choking zone has been provided in the form of an axially adjustable convergent cone, disposed adjacent the delivery end of the rotor as illustrated, for example, by the patent to Burr et al. 652,665, to effect a final squeeze on the now relatively dry pulp,

Choking action, as referred to, to increase the liquid yield, has met with only limited success. It has been found that if pressure near the rotor outlet is increased beyond a certain point the pulp will rotate with the rotor rather than be conveyed by it. This undesirable operation has been improved to some extent by employing stop members which prevent rotation of the pulp with the rotor, the patent to lung 3,002,446 being illustrative of this technique, This, however, has not been entirely successful since further increase in pressure at the rotor discharge end produces an effect in which some of the mass is stationary and some rotating with the rotor, producing shear planes between the rotary and stationary masses, again clogging the desired continuous flow of the material. The use of stops moreover, as in the lung patent, necessarily entails forming the vanes, flights or threads, as variously known in the art, as discontinuous members so that their ends may rotate across the stops.

Conventional presses of the type referred to would thus operate in a more efficient manner, by extracting a greater percentage of liquid from the pulp, if the pressure adjacent the discharge end of the rotor could be increased without producing the clogging action referred to. As will subsequently apear, the principal objectives of the present invention are to increase the liquid yield from the pulp by increasing the squeezing pressure, yet maintaining a continuous positive displacement flow of same without clogging.

SUMMARY OF THE INVENTION A frusto'coziical rotor of generally conventional design is provided with a continuous conveying and compacting vane which is mounted for rotation about a fixed axis within a surrounding screen, the cross-sections of the latter being of oblate circular shape and angularly twisted about the longitudinai axis of the screen in such manner that the ends of their major and minor axes lie along helical paths. The longitudinal reference axis of the screen is positively gyrated about the rotor axis in a predetermined orbit and in synchronism with rotor rotation to provide substantially constant clearance between all points on the outer periphery of the vanes and corresponding laterally adjacent points in the inner periphery of the screen.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a longitudinal central section of the subject of the invention, portions being omitted;

FIG. 2 is a section taken on line 2-2, FIG. 1;

FIG. 3 is a reduced scale section taken on line 3-3, FIG. 1;

FIG. 4 is alike section taken on line 4-4, FIG. 1; and

FIG. 5 is a section illustrating an alternative form of the in vention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing and first to FIG. I, rotor 10 comprises an upper cylindrical shaft portion 12 and a lower frusto-conical portion 14 to which is affixed a continuous spriral flight or vane 16. The upper end of the shaft is jour' naled in a bearing 18, affixed to a suitable frame, such as a floor ofa building, and its lower end provided with a stub shaft 20, journaled in bearing 22, also affixed to the frame, which may be the next lower floor of the building. The weight of the rotor is absorbed by thrust bearing 24. All bearings referred to have been illustrated as plain bearings, in the interests of simlification of the drawing, however, it is to be understood that these are preferably of the anti-friction type employing balls or rollers to minimize bearing friction losses. The structure so far described thus mounts the rotor for rotation about a fixed axis 26, its upper end being drivingly connected to any suitable power drive 28 which, for example, may be a speed reducer disposed between the shaft and a motor (not shown). A discharge hopper 30 is disposed surroundingly adjacent the lower end of the rotor, supported by a spherical surface 32 on bearing 22, engaging a corresponding surface 34 on the lower end of the discharge hopper. A cylindrical wall 36 partitions the discharge hopper into an outer annular liquid drain trough 38 and inner pulp passageway 40. Wall 36 telescopically receives a convergent outlet choking ring 42 which may be axially adjustable, as indicated by the double head arrow on same, in any suitable manner. As will subsequently more fully appear, the discharge hopper is mounted in such manner to permit its longitudinal axis 44 to gyrate around rotor axis 26, the point of zero gyration being at a point 46 where the axes intersect. This is preferably located at a point beyond the lower end of the rotor cone so that some appreciable gyration occurs adjacent its lower endv To permit gyration of axis 44, but to prevent rotation of the discharge hopper about such axis, rotation restraining means must be employed, which is illustrated as at least one stop pin 48, affixed to the hopper and engageable with a fixed stop or abutment 50. The pin or pins may move in the direction indicated by the double head arrows on same, to permit gyration, but to prevent rotation. Other unshown modes of preventing rotation include one or more cables extending between the hopper and fixed structure or a circularly arranged set of parallel stop pins extending downwardly from the hopper, the ends of which loosely engage teeth of a non-rotatable concentric sprocket. The remaining illustrated portions of the discharge hopper include a flexible boot 52 which provides a seal between stub shaft 20 and the discharge hopper, a liquid efflux hose 54, and a pulp efflux conduit 56.

The foraminous envelope 58 surrounding the rotor comprises, in general, an open framework in the form ofa plurality of spaced rings 6011,6017, 60:1. two of which are shown at its upper end and one at its lower end. the remainder therebetween being omitted to simplify the drawing, which are secured together by welded angularly spaced plates 62. The inside surfaces of the framework are lined with foraminous material 64, such as woven screen or perforate sheet metal, hereinafter referred to as a screen. The various rings differ in shape along the length of the screen as illustrated by the two extremes, FIGS. 3 and 4. In the modification shown, assuming that all points on the outer edge of vane 16 he on the surface of a cylinder, the major axes 66 of all rings are of substantially constant length but their minor axes 68 decrease from the bottom toward the top. Thus, as illustrated in FIG. 4, ring 6% is slightly oblate whereas ring 60a is considerably more oblate,

this change in shape being required since the magnitude of gyration of axis 44 increases in a direction from its lower to its upper end The adjacent rings 60a, 60b, etc. are also angularly indexed so that the ends of axes 66, 68 lie along two spiral paths 180 apart. Thus, if vane 16 forms a right-hand thread, then the spiral paths referred to form a double right-hand thread. The shape of the screen may also be visualized by forming a tube of variable oblate cross-sections and then twisting it about its longitudinal axis.

A feed hopper 70 is rigidly secured to uppermost ring 60a and is provided with a spherical type bearing 72, the inner race of which slideably receives a crank pin 74, secured to a gear 76, driven by a gear 78, affixed to shaft 12, at a 1:1 ratio. As best shown in FIG. 2, the axis of the crank pin moves in a circular orbit 80 in an opposite direction of rotation of shaft 12, completing its orbit in one revolution of shaft 12. At 180 from the position shown in FIG. 2, hopper 70 moves to the dotted position of FIG. 1, thence returning to the position shown.

As in conventional presses, a removable imperforate jacket or housing 82, surrounding the screen, may be provided if desired to direct expressed liquid into trough 38. This may be omitted, however, when all of the liquid would normally drain along the screen and into the trough.

FIG. illustrates another manner of supporting screen 64 for gyration of its axis. In this construction, discharge hopper 30 is fixed, rather than gyratory, and the lowermost flange 60 is provided with a spherical surface which rests on a like surface on the discharge hopper, the axis 44 of the screen intersecting rotor axis 26 as previously described.

In the modification shown to illustrate the invention, the press is constructed so that the rotor rotates and the screen simultaneously gyrates in synchronism; however, the invention is not limited to this arrangement as the press may be constructed so that the screen rotates and the rotor gyrates in synchronism, or it may be constructed so that either the rotor or screen both rotates and gyrates simultaneously.

It will be apparent to those skilled in the art that various changes may be made in the apparatus disclosed without departing from the spirit of the invention and it is intended, accordingly, that all such changes shall be embraced within the scope of the claims.

I claim:

1. In a press of the type for extracting fluid from vegetable material and the like, said press being of the type having an elongated rotor member with a helical vane on its outer surface, rotatable about its longitudinal axis within a surrounding screen member having a longitudinal non-rotatable reference axis, the rotor and screen members having corresponding feed and discharge ends, the sectional area transverse to said axes decreasing in a direction from the feed to the discharge ends, for producing progressively increasing pressure on said material, the improvements, in combination, comprising:

a. the transverse sections of said screen being of circularly oblate form with substantially constant length major axes and increasing length minor axes, in a direction from the feed to discharge ends;

b. the ends of said axes being progressively disposed along angularly spaced helical paths;

c. means mounting said members for relative gyratory movement about a point disposed beyond their discharge ends and at which their axes intersect, whereby the amplitude of gyration uniformly diminishes in a direction from the feed to the discharge ends; and

d. means for positively gyrating at least one of said mem' bers, means for simultaneously rotating at least one of said members, means for synchronizing said rotary and gyratory motions for producing substantially uniform clearance between all points on the outer periphery of the vanes and corresponding laterally adjacent points on the inner periphery of the screen.

2. A press in accordance with claim 1 wherein the rotor rotates about a fixed axis and the reference axis of the screen gyrates around said fixed axis.

3. A press in accordance with claim 2 including mechanism drivingly connected to the rotor for gyrating said screen in an orbital path, opposite to the direction of rotation of the rotor, and in predetermined ratio therewith.

4. A press in accordance with claim 3 wherein said ratio is 1:1, whereby the screen gyrates through one complete orbit during one revolution of the rotor.

5. Apparatus in accordance with claim 4 including a feed hopper affixed to the feed end of the screen, and a bearing affixed to the feed hopper forming a portion of said mechanism.

6. Apparatus in accordance with claim 5 wherein said bearing is of the spherical type and said mechanism includes an eccentrically driven member engaging said bearing.

7. Apparatus in accordance with claim 2 including a discharge hopper affixed to the discharge end of the screen and gyratable therewith.

8. Apparatus in accordance with claim 2 including -a fixed discharge hopper disposed adjacent the discharge end of the screen, the screen being gyratable relative thereto.

9. Apparatus in accordance with claim 2 including means connecting said screen to fixed structure to prevent rotation of the screen about its longitudinal reference axis and to permit gyration of same around said fixed axis.

10. A positive displacement press for separating liquids from compressible solids comprising:

a. a rotor having at least one continuous helical vane, projecting from its outer surface;

b. a helically-shaped screen surrounding said rotor;

c. means for producing sychronized relative gyratory motion between longitudinal axes of the screen and rotor; and

d. the construction and arrangement being such that substantial uniform clearance is maintained between the vane and screen.

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