Title:
PRESS
United States Patent 3688687
Abstract:
A press is provided, particularly adapted for the extraction of water from solids generally delivered to the press in slurry form. The slurry is delivered to the press at a lower end thereof, or in the alternative, to a pair of presses, at a lower end thereof, with the press being generally elongated, cylindrical and upstanding. A foraminous cylindrical screen is disposed within a shell, and with a delivery screw being mounted for rotation within the screen, such that the slurry is delivered through the lower end of the shell, to the screen, with flights on the screw being adapted, upon rotation of the screw, to lift the slurry upwardly, and with the screw being adapted at its upper end to promote a squeezing of the slurry carried thereby, for squeezing water therefrom, for passage outwardly through the foraminous screen, and down through the shell, to discharge. Particularly novel screen retaining means, and slurry inlet means are herein provided.


Inventors:
Sam, Craig N. (Devon, PA)
Ellis Jr., Warner R. (West Chester, PA)
Wayne, Buckman T. (Pipersville, PA)
Application Number:
05/089853
Publication Date:
09/05/1972
Filing Date:
11/16/1970
Assignee:
Wascon Systems (Inc., Hatboro)
Primary Class:
Other Classes:
100/145
International Classes:
B30B9/12; (IPC1-7): B30B9/18
Field of Search:
100/117,37,145,146,147,148,149,150 241
View Patent Images:
US Patent References:
3426677SCREW PRESS1969-02-11Combs et al.
3375776Disintegrating material in a liquid carrier and separating the same1968-04-02Dyson
3319897Waste disposal unit1967-05-16Craig et al.
3188942Apparatus for disintegrating and dewatering fibrous material1965-06-15Wandel
2960926Screw press1960-11-22McKee
Primary Examiner:
Peter, Feldman
Attorney, Agent or Firm:
Paul & Paul
Claims:
1. A generally upright press for extracting water from a slurry of solids comprising an elongated shell, a generally upright conveyor screw having spiral ribbon flight means disposed within said shell for rotation therein and for lifting solids thereby, an elongated tubular screen generally circular in transverse section having an inner wall disposed generally concentrically about the screw and inside the shell, including slurry inlet means opening into the inside of the screen and to the screw at the lower ends thereof, water outlet means opening from the lower end of the shell for passage of drain water therethrough, and solids outlet means from the upper end of the screen for delivery of pressed solids therethrough, wherein said slurry inlet means is tangential inlet means and includes lateral directing means for directing incoming slurry away from the inner wall of the screen and radially toward the center of the lower end of the circular screen, into contact with the screw.

2. The press of claim 1, wherein said inlet means comprises a tubular section opening tangentially into the lower end of the circular screen, and wherein said directing means comprises diverting means carried by said tubular section along a wall portion of said tubular section that is tangential with said screen.

3. A generally upright press for extracting water from a slurry of solids comprising an elongated shell, a generally upright conveyor screw having spiral ribbon flight means disposed within said shell for rotation therein and for lifting solids thereby, an elongated tubular screen generally circular in transverse section disposed generally concentrically about the screw and inside the shell, including slurry inlet means opening into the inside of the screen and to the screw at the lower ends thereof, water outlet means opening from the lower end of the shell for passage of drain water therethrough, and solids outlet means from the upper end of the screen for delivery of pressed solids therethrough, wherein said slurry inlet means includes means for directing incoming slurry toward the center of the lower end of the circular screen, into contact with the screw, wherein said inlet means comprises a tubular section opening tangentially into the lower end of the circular screen, and wherein said directing means comprises diverting means carried by said tubular section along a wall portion of said tubular section that is tangential with said screen, including additional diverting means comprising a portion of said inlet means for directing incoming slurry in a direction having a component parallel to the axis of screw rotation and in a solids lifting direction.

4. The press of claim 3, including a plate of a diameter substantially equal to that of the circle described by the screw flight means during rotation thereof, being carried by said screw for rotation therewith at the lower end of and against said screw flight means, with said inlet means opening into the interior of said screen above said plate.

5. The press of claim 1, wherein said directing means comprises an inlet conduit that defines a flow path toward said screw such that the geometric center of flow path intersects the axis of said screw.

6. A generally upright press for extracting water from a slurry of solids comprising an elongated shell, a generally upright conveyor screw having spiral ribbon flight means disposed within said shell for rotation therein and for lifting solids thereby, an elongated tubular screen generally circular in transverse section disposed generally concentrically about the screw and inside the shell, including slurry inlet means opening into the inside of the screen and to the screw at the lower ends thereof, water outlet means opening from the lower end of the shell for passage of drain water therethrough, and solids outlet means from the upper end of the screen for delivery of pressed solids therethrough, wherein said slurry inlet means includes means for directing incoming slurry toward the center of the lower end of the circular screen, into contact with the screw, wherein said directing means comprises an inlet conduit that defines a flow path toward said screw such that the geometric center of flow path intersects the axis of said screw, including diverting means comprising a portion of said inlet means for directing incoming slurry in a direction having a component parallel to the axis of screw rotation and in a solids lifting direction.

7. A generally upright press for extracting water from a slurry of solids comprising an elongated shell, a generally upright conveyor screw having spiral ribbon flight means, disposed within said shell for rotation therein and for lifting solids thereby, an elongated tubular screen generally circular in transverse section disposed generally concentrically about the screw and inside the shell, including slurry inlet means opening into the inside of the screen and to the screw at the lower ends thereof, water outlet means opening from the lower end of the shell for passage of drain water therethrough, and solids outlet means from the upper end of the screen for delivery of pressed solids therethrough, wherein said slurry inlet means includes means for directing incoming slurry toward the center of the lower end of the circular screen, into contact with the screw, wherein an additional press is provided in the combination, including an additional screw, screen and shell, each disposed generally parallel to the first mentioned screw, screen and shell, and wherein said slurry inlet means comprises a common inlet for both said presses, with both presses having a common inlet conduit comprising said directing means and defining flow paths toward said screws such that the geometric center of each flow path intersects the axis of its associated said screw, and with each said conduit including diverting means for directing incoming slurry in a direction having a component parallel to its associated screw axis and in a solids lifting direction.

8. The press of claim 7, including plates, each of a diameter substantially equal to that of the circle described by an associated screw flight means during rotation thereof, being carried by each screw for rotation therewith at lower ends thereof and against associated said screw flight means, with associated said inlet conduit paths opening into the interiors of associated screens above associated said plates.

9. The press of claim 1, with the inner surface of the screen being of a circumference only slightly greater than the circumference defined by the radial outermost portions of the screw during its rotation within the screen, with the screen being constructed of a material and having a thickness that would permit flexing of the screen upon rotation of the screw therein for pressing water from a slurry delivered within the screen to the screw, and including means comprising reinforcing bands disposed about the screen for retaining the generally circular shape of the screen during rotation of the screw therein for pressing water from the slurry.

10. A generally upright press for extracting water from a slurry of solids comprising an elongated shell, a generally upright conveyor screw having spiral ribbon flight means, disposed within said shell for rotation therein and for lifting solids thereby, an elongated tubular screen generally circular in transverse section disposed generally concentrically about the screw and inside the shell, including slurry inlet means opening into the inside of the screen and to the screw at the lower ends thereof, water outlet means opening from the lower end of the shell for passage of drain water therethrough, and solids outlet means from the upper end of the screen for delivery of pressed solids therethrough, wherein said slurry inlet means includes means for directing incoming slurry toward the center of the lower end of the circular screen, into contact with the screw, with the inner surface of the screen being of a circumference only slightly greater than the circumference defined by the radial outermost portions of the screw during its rotation within the screen, with the screen being constructed of a material and having a thickness that would permit flexing of the screen upon rotation of the screw therein for pressing water from a slurry delivered within the screen to the screw, and including means comprising reinforcing bands disposed about the screen for retaining the generally circular shape of the screen during rotation of the screw therein for pressing water from the slurry, including diverting means comprising a portion of said inlet means for directing incoming slurry in a direction having a component parallel to the axis of screw rotation and in a solids lifting direction.

11. A generally upright press for extracting water from a slurry of solids comprising an elongated shell, a generally upright conveyor screw having spiral ribbon flight means, disposed within said shell for rotation therein and for lifting solids thereby, an elongated tubular screen generally circular in transverse section disposed generally concentrically about the screw and inside the shell, including slurry inlet means opening into the inside of the screen and to the screw at the lower ends thereof, water outlet means opening from the lower end of the shell for passage of drain water therethrough, and solids outlet means from the upper end of the screen for delivery of pressed solids therethrough, wherein said slurry inlet means includes means comprising a portion of said inlet means for directing incoming slurry in a direction having a component parallel to the axis of screw rotation and in a solids lifting direction.

Description:
In the recent past, there has been a distinct tendency away from trash pick-up by conventional means, and toward the handling of trash by various other techniques.

For example, the high labor costs attendant to conventional pick-up of trash have created a need for minimizing the necessity of such pick-up or of eliminating the same altogether. Generally, great quantities of trash thus collected has caused a substantial storage or disposal problem, which has, in the past, been answered generally by incinerating the trash, principally for purposes of reducing its solids volume to a form more readily disposed of; i.e., the disposition of ashes only, rather than the bulk of unburned trash.

Ecological concerns, however, dictate against the incineration of refuse, so other techniques have been developed for the handling of such refuse. Such techniques have involved, in some instances, the reduction in size or volume of the trash, which itself, represents a substantial reduction in the disposal problem. By compacting trash, the same may be more readily disposed of, by use as land fill or the like. Furthermore, by compacting trash, the labor problems attendant to collection and removal of the same are substantially reduced, principally because of the sheer reduction in volume of the trash. This is particularly true with respect to various institutions that tend to promote large quantities of trash that require specialized handling, rather than trash generated domestically, as in homes. Such institutions may include hospitals, office buildings, apartment complexes, and the like, where huge quantities of trash are generated on a daily basis.

Generally such trash is comminuted into very small particle sizes in a pulping apparatus of the type disclosed in U.S. Pat. No. 3,489,356, issued Jan. 13th, 1970, the disclosure of which is herein incorporated by reference. The slurry from that type of pulping apparatus is then generally delivered to a press of the type disclosed in U.S. Pat. No. 3,426,677, issued Feb. 11th, 1969, the disclosure of which is also herein incorporated by reference. Also, the slurry may be subjected to other grinding or comminuting stages prior to being delivered to the press, if desired. Thus, a press of the type disclosed in U.S. Pat. No. 3,426,677 is generally operative in the intended manner, to squeeze the water from the slurry, and to deliver solids from the slurry, to a discharge location, wherein it may be collected in a bin or the like, in substantially reduced volume from that trash which was originally delivered to a pulper, for collection and disposal.

The press of the type disclosed in U.S. Pat. No. 3,426,677 has proven to be highly successful in its operation, but various improvements and refinements have been made on the same, for handling specialized problems attendant to the use of such a press.

The present invention is most particularly directed to the solution of such specialized problems.

One such problem resides in the use of a foraminous screen disposed about the press screw. In some instances, certain forms of trash, such as slurry components of rags and the like, may collect and aggregate, often tending to fill the flight clearance in the press, and become wedged between the flights of the screw and the inside surface of the cylindrical foraminous screen. If such solids components, such as rags, paper or the like are sufficiently large in size they can tend to jam the screw and screen. Even in those instances when such solids components are not so large that they could tend to jam between the screw and screen, they may tend to collect along the flights and ride around the inside surface of the screen, carried by the screw flights, pushing the screen outwardly as that portion of the flight rotates. This outward pushing of the screen would happen cyclically, and tends to "work" or constantly rub the screen.

The screens are generally of rather thin material construction. This thickness of the screen material is dictated by the particle size to be handled by the press, in that, it is not desired, for efficient operation of the press, that particles would pass through the holes in the screen. For example, it is desired in many instances, to maintain the size of holes in the screen to less than three thirty-seconds of an inch. Often, the desired hole size is even smaller. If the material of construction of the screen is too thick; i.e., heavier than 14 gage (as would generally be used for a press screw of 12 inches in diameter), it is not generally possible to economically construct screen holes less that three thirty-seconds of an inch in diameter. Thus, this poses a practical limitation upon the allowable thickness of the cylindrical screen.

An even further limitation exists upon the thickness of the screen, even if it were practical and desirable to construct a thick screen having holes therein that are sufficiently small in size, in that, the minute fibers from the slurry that otherwise would pass through the screen, if such fibers are very long, would tend to become collected on the inside surface of the screen, often "straddling" adjacent holes for example, because the holes in the screen would define what would amount to an elongated passage through the screen. Thus, considering the limitation imposed upon the size of holes in the screen, thick screens would tend to promote a gathering or collection of fibers on the inside surface thereof, which would build up until they either jammed the press screw against rotation relative to the screen, or until they precluded drainage of water through the screen.

Accordingly, it has been found, in accordance with this invention, to be desirable to rigidify the screen, for maintaining the screen close to the screw flight, without increasing its thickness.

Another problem that has been discovered, is that, by providing a slurry inlet to the screw disposed inside the screen, that is tangential in nature, the solids in the slurry delivered to the screw are first delivered immediately to the screen, from which they must be lifted by the screw. However, a tangential inlet to the press was deemed to be desirable, in order that the slurry could most quickly be lifted upwardly by the flight.

A further problem that has existed resides in the delivery of slurry to the bottom of the screw wherein the particles may fall directly to the bottom of the screen, particularly against one end wall thereof. It has been found that this can permit the slurry to accumulate unlifted at the bottom of the screw, clogging the screen lower end.

The present invention is directed toward the solution of the press problems set forth above, in providing a screen which is sufficiently rigid but thin, by providing bands for retaining the screen in its desired circular shape during the pressing operation. Also, the slurry being delivered to the screen is delivered through a tangential inlet, that is provided with a deflector that deflects the slurry away from the interior surface of the screen, for initial delivery toward the center of the screw, generally in the direction toward the axis of rotation of the screw, with a plate being provided, secured to and carried by the lower end of the screw, and with an upward deflector at the inlet of the slurry to the screw, whereby the slurry being delivered to the press may be deflected upwardly onto a bottom flight thereof, away from the foraminous end portion of the press screen, and with the collection of solids at the bottom of the screen being also prevented.

Accordingly, it is a primary object of this invention to provide a novel press for extracting liquids from solid slurrys.

It is another object of this invention to accomplish the object set forth immediately above, by providing a novel shape-retaining means for the press screen.

It is a further object of this invention to provide a device for accomplishing the initial object hereinabove set forth, by providing slurry inlet means which is adapted to direct the slurry toward the center of the screw, rather than against the screen walls.

It is a further object of this invention to provide a novel slurry inlet means for directing the incoming slurry upward onto a screw flight.

It is a further object of this invention to provide a novel method of maintaining the disk-like portion of the screen at the lower end thereof, free of particle accumulation thereon.

It is a further object of this invention to accomplish all of the above objects, wherein the press is of the dual press type, having a generally common slurry inlet.

Other objects and advantages of the present invention will be readily apparent to those skilled in the art from a reading of the following brief descriptions of the drawing figures, detailed description of the preferred embodiments, and the appended claims.

IN THE DRAWINGS

FIG. 1 is a side elevational view, substantially in section, of a press in accordance with this invention.

FIG. 2 is a transverse sectional view of the press of FIG. 1, taken generally along the line II--II of FIG. 1, and wherein certain portions are illustrated as being broken away, for the sake of clarity.

FIG. 3 is an enlarged fragmentary vertical sectional view, of the bottom portion of the press illustrated in FIGS. 1 and 2, taken generally along the line III--III of FIG. 2, and wherein the details of slurry inlet and the lower end of the screw are most clearly illustrated.

FIG. 4 is a perspective view of a structure adapted for slurry inlet, in accordance with this invention, and represents one of the components of slurry inlet for the press illustrated in FIG. 1.

FIG. 5 is a fragmentary vertical sectional view of the inlet for a press of the dual screw type as illustrated in FIG. 6, taken generally along the line V--V of FIG. 6.

FIG. 6 is a transverse sectional view, taken through a dual screw type of press, in accordance with this invention, and wherein the common slurry inlet therefor is clearly illustrated.

FIG. 7 is an enlarged view of a portion of the slurry inlet for the dual screw arrangement of FIG. 6, taken generally along the line VII--VII of FIG. 5, and wherein certain portions only of the remainder of the press apparatus are illustrated in phantom, for clarity of illustration of the slurry bottom inlet plate.

Referring now to the drawings in detail, reference is first made to FIG. 1, wherein a press generally designated by the numeral 10, is illustrated.

The press 10 is provided with a mounting structure, generally of angle iron configuration or the like, identified by the numeral 11, for holding the press 10 at a desired selected angle with a vertical direction, generally at an angle of 15 degrees from vertical, although this angle can vary. In fact, if desired, the press 10 can be disposed precisely vertical.

The press 10 includes a shell 12, of generally rectangular cross-sectional configuration, although the same can be circular, if desired. The shell 12 is provided with a bottom wall 13, and an upper discharge end 14. A conveyor screw of the helical type 15 is provided, and includes a ribbon flight 16 carried on a shaft 17, which may optionally be provided with a brush on its outer periphery, secured thereto by any suitable means, such as retainer clips or the like (not shown). The shaft 17 is provided with an upper configuration 20, for squeezing of pulp thereagainst, such portion 20 being constructed in the manner of that disclosed in U.S. Pat. No. 3,426,677. An electric motor 21 is provided, for driving the shaft 17 through a suitable drive train 22.

At the upper end of the press 10, just below the solids discharge portion 14 of the press 10, a hopper 23 is provided, for assisting the flow of pressed solids being delivered from the press 10, into a bin or suitable receptacle (not shown). It will be noted that the angular orientation of the press 10, with the vertical direction enables the ready flow of pressed solids across a hopper 23, into a bin, and this therefore presents one reason as to why the angular orientation of the press 10 is desirable.

With particular reference to FIGS. 2, 3 and 4, it will be noted that the pulp inlet comprises a delivery line 24, which terminates in a flange 25, which is secured to a connection plate 26, by means of suitable bolts or like connectors 27, with a gasket 28 disposed therebetween. The plate 26 is, in turn, secured to the shell sidewall 30 with a gasket 31 therebetween, by the use of cap headed screws 32, which also facilitate the carrying of an inlet flange 33 by the shell 30, with a suitable gasket 34 therebetween, as is best illustrated in FIG. 3.

The inlet flange 33 contains a passage portion 35 and an end portion 36, with the end portion 36 facilitating the mounting of the inlet flange 33. The passage portion 35 of the inlet flange 33, communicates with the interior of the inlet line 24, and also communicates with a tangential inlet portion 37, of foraminous construction, similar to the material of construction of the screen 19, similar to the comparable foraminous inlet construction described for the comparable press inlet of the patented press identified above.

The inlet flange 35, is best illustrated in FIG. 4, in detail. It will be noted that the conduit-like portion 33 thereof is provided with an anuglarly directed diverter or deflector portion 38, that is adapted to deflect the incoming slurry in a direction toward the axis or center of rotation of the screw shaft 17, or substantially parallel thereto. This is best illustrated in FIG. 2. The deflector portion 38 may form an integral part of the conduit portion 33, and be of sheet metal construction, bent inwardly as illustrated in FIG. 4, or such may comprise an additional piece of metal or the like disposed within the passage portion 33 of the inlet flange 35, in a manner not illustrated. Thus, the deflector portion 38 comprises a lateral deflector. A vertical diverter or deflector 40 is also provided, as illustrated in FIGS. 4 and 3, for deflecting incoming slurry slightly upwardly, to have an upward component of travel as the slurry enters the cylindrical portion of the screen 15, as illustrated in FIG. 3, in order that the incoming slurry may receive an initial direction or path of flow to place such slurry into the screen 19, above the lowermost end of the flight 16 of the screw 15.

Thus, as slurry enters the screen 19, it will have an initial upward direction, which will be compatible with the upward direction of thrust imparted to such slurry by the screw flight 16. At the lowermost end of the screw flight 16, there is welded or otherwise suitably secured to the shaft 17, a bottom plate 51, for rotation of the plate 41 with the screw 15, as the same rotates, with the plate 41 serving to keep fibers, particles and like debris from gathering against the foraminous screen portion 42 therebeneath, illustrated in FIG. 3. Thus, the plate 41 will prevent an accumulation of debris against the bottom screen portion 42, thereby permitting the free flow of water squeezed from pulp within the screen 19, through the holes at the bottom of the screen end 42. Water thus passing through the screen 19 may then be delivered through the water outlet 43, as with water passing through other holes of the cylindrical portion of the screen 19, for either gravity discharge, or for pumping back through the system, or externally thereof, as desired.

In order that the desired light gage material (preferably sheet metal) may be used for the construction of the cylindrical portion of the screen 19, the screen is banded by appropriate bands 44, best illustrated in FIGS. 1, 2 and 3. The bands 44 may comprise any desired form, but such are generally comprised of two semi-circular portions 45 and 46, substantially identical in construction, each with flanges 47, adapted to be connected by suitable bolts 48, or the like. The number and placement of the bands 44 may be selected, in accordance with the particular size of the press to be used, and the material on which it is to be used, such as will maintain the desired cylindrical configuration of the screen 19, without permitting undesired flexing of the same during rotation of the screw 15 therein, and such as will maintain the screen 19 sufficiently close to, or against the edges of the flights 16, or brushes 18 carried thereon. Thus, it will be apparent that is is possible to utilize a screen 19 of the desired thickness, that will permit holes of the desired thickness therein to avoid the problems set forth herein above, and others.

It will be noted, that the other details of construction and operation of the press 10 that are not specifically described herein, conform generally to the press described and illustrated in U.S. Pat. No. 3,426,677.

With particular reference to FIGS. 5, 6 and 7, it will be noted that there is provided a press generally designated by the numeral 50, that is of the twin screw type, utilizing a pair of screws 51 and 52, disposed within respectively corresponding cylindrical screens 53 and 54.

The screws 51 and 52 are provided with a common slurry inlet 55, generally of foraminous tubular configuration, as are the screens 53 and 54 of foraminous configuration. Disposed on the bottom plate portion 56 of the inlet 55 is a bottom plate 57, which has a generally triangularly configured portion 58, and angularly upwardly bent portions 60 and 61, as illustrated in FIGS. 6 and 7, for directing the incoming slurry to have an upward component of direction, to assist the disposition of such slurry onto flights of the screws 51 and 52, in a manner generally similar to that described above for the upward deflector 40 of the press 10. Also, the placement of the inlet zones 62 and 63 facilitates the entry of incoming slurry from the passage 55 toward the axis of rotation of the respective screws 51 and 52, thereby serving as radial inward deflectors, for deflecting such slurry in a radial inward direction or, parallel thereto, generally similar to the purpose served by the deflector 38 of the press 10. It will be apparent that other features of the press 10 would also be incorporated in the twin screw press 50, such as the use of bands, bottom screw plates and the like, and that the entire arrangement illustrated in FIG. 6, for example, would be disposed within a shell (not illustrated), that would also encompass the foraminous inlet 55, with suitable provision for drainage of water from pressed solids, and for disposal of pressed solids outwardly of the upper ends of the screens 53 and 54, in a manner generally similar to that illustrated in FIG. 1.

It will be apparent from the foregoing that various modifications may be made in the details of construction, as well as the use and operation of the device of the instant invention without departing from the spirit and scope of the invention as recited in the appended claims.