US3357345A

US3357345A - Apparatus for liquid removal

Info

Publication number: US3357345A
Application number: US429755A
Authority: US
Inventors: Alan R Hamilton
Original assignee: Rice Barton Corp
Current assignee: Rice Barton Corp
Priority date: 1965-02-02
Filing date: 1965-02-02
Publication date: 1967-12-12
Anticipated expiration: 1984-12-12
Also published as: DE1486817A1; GB1123442A

Description

Dec. 12, 1967 A. R. HAMILTON 3,357,345

APPARATUS FOR LIQUID REMOVAL Filed Feb. 2, 1965 3 Sheets-Sheet l Dec. 12, 1967 Q A. R. HAMILTON APPARATUS FOR LIQUID REMOVAL 3 Sheets-Sheet 2 Filed Feb. 1965 Dec. 12, 1967 A. R. HAMILTON 3,

APPARATUS FOR LIQUID REMOVAL Filed Feb. 1965 3 Sheets-Sheet 5 United States Patent 3,357,345 APPARATUS FOR LIQUID REMOVAL Alan R. Hamilton, Paxton, Mass, assignor to Rice Barton Corporation, Worcester, Mass, a corporation of Massachusetts Filed Feb. 2, 1965, Ser. No. 429,755 11 Claims. (Cl. 100-158) ABSTRACT OF THE DISCLOSURE A screw filter coupled through a closed circuit to a disc press input zone, with a pressure sensor in the input zone to vary the disc speed to keep input pressure constant. Other features include labyrinth disc seals, a doctor incorporating a wash water chamber and a knot removing auger, and a shredder.

This invention relates to apparatus for reducing the liquid content of a mixture of liquid and solid material.

It is a primary object of the invention to provide such apparatus which combines simplicity of operation and maintenance with flexibility and high throughput capability. It is a further important object to provide enclosed two-stage combination apparatus for successively removing liquids in large quantity in screw filter and disc press stages. A further significant object is provision of such a screw filter compact in size and yet operable at increased pressures and rates of throughput, and with reduced loss of fines. Another important object is provision of such a disc press in which bearing requirements are simplified and production of knots is minimized. Another important object is provision of such a disc press capable of operating efliciently during fluctuation of rate of input. Other important objects are provision in a disc press for operating on thinner slurries, for removal of knots that do form, and for washing out without shutdown. Another important object is to provide for ejection from a disc press of damp solids shredded for eflicient pneumatic conveying.

The invention features in its combination aspect an enclosed system in which a screw filter discharges directly into a disc press. In preferred embodiments of the screw filter subcombination, there are featured axes of symmetry in which that of one or both extremities is at an angle to that of the center portion, eliminating blind corners and related build-up and undesirable back pressure at the output end and permitting stacking of the screw filters in series; screws removable in half flights from the screw shaft; and outer helical surfaces of said screws defined by bristles of metal, such as stainless steel or brass. In preferred embodiments of the disc press subcombination of the invention are featured mounting the pair of frustoconcal discs for rotation about axes in the same hori zontal plane, inlet pressure sensing means for varying disc rotation rate, labyrinth disc seals, and a doctor member incorporating a wash water chamber and a knot-removing auger. Also featured, in combination with a disc press, is a shredder comprising a multiplicity of teeth moved to engage the pressed product coming from the disc press.

Other objects, features, and advantages will appear from the following description of a preferred embodiment of the invention, taken together with the attached drawings thereof, in which:

FIG. 1 is a side elevation, to a large extent broken away in vertical section, thereof;

FIG. 2 is a section at 22 of FIG. 1;

FIG. 3 is a section, broken away, at 3-3 of FIG. 1;

FIG. 4 is a partial end elevation;

FIG. 5 is a broken away sectional view of a portion of the filter screw, taken on a plane through the axis thereof;

FIG. 6 is a somewhat diagrammatic view of screw filter showing the head adjustment standpipe in two positions; and

FIG. 7 shows two screw filters in series.

Referring now more particularly to the drawings, there is shown-in FIG. -1 liquid removing apparatus adapted to, for example, bring solids content of slurries ofpfood fiber in water from 4% or less to 40% or more.

The liquid removing apparatus includes a screw filter, indicated generally at 10, secured at its outlet end to a disc press, indicated generally at 12.

The screw filter 10 has a stainless steel screw .14 mounted for rotation on shaft 16 carried. by

bearings

18 and 20..Bearing 18 is water-lubricated, with a Micarta bushing. Bearing 20 is provided with roller bearings. Screw 14 is in two parts 14a and 14b,,each of which surrounds the shaft 16 for and may easily be disassembled for cleaning or maintenance. Secured all along the helical edge of the main portion 22 of screw 14 are bristles 24 of stainless steel, which define .a helical brush. The outer surface of this brush is ground for .dimensional precision; the length-of the bristles before grinding is indicated (FIG. 5) in dotted lines. Also in two semicylindrical portions are perforated stainlesssteel plate filtering screen 26 and stainless steel casing 28, both of which like the screw are bisected essentially by a plane in which lies the axis of both. (A gasket, not shown, is provided between the two casing halves.) The lower half of casing 28 is secured at its lower end to base 30, a 45 elbow with stainless steel stock contacting surfaces, and at its top to stainless steel member 32,.the end of which is also symmetrical about an axis at 45 to the axis of shaft 16, making removal of the top half simple for maintenance or cleaning. Mounted on shaft 16 for selective longitudinal positioning thereon is lump breaker 34, which may be moved up or down as it is desired respectively to decrease or increase operating pressure within screen 26. The shaft 16 is driven by motor 36 through belt 38. Effective head may also be modified by using standpipe 39, as shown in FIG. 6. Use of more thanone of the screw filters 10 is shown in FIG. 7; such use is facilitated by having the inlet and outlet axes of each filter diverge oppositely from the screw axis.

Slurry thickened in the screw filter 10 emergestherefrom directly into inlet zone 40 of housing 42 (cast from Meehanite CC acid-resisting iron) of disc press 12. Beneath zone 40 are portions of two discs44 with frustoconical pressing surfaces 46. Each surface 46 includes a multiplicity of holes 48 which extend throughthe discs. The holes 48 communicate with liquid-collecting concentric grooves 50 and radial grooves 52 (FIG. .1, shown n the upper right-hand quadrant, where the'screen is broken away). The axes of

rotation

54 and 56 of discs 44 are in the same horizontal plane, which among other things gives the advantage of simplifying. bearing requirements (FIG. 2). The discs are rotated thereabout by motor 58, which drives them through gears 60, the outer peripheriesof the discs constituting mating bevel gearing. The discs are'held on shafts 59 by locking plates61. Each pressing surface 46 is covered by stainless steel screen 62 (FIG. 1), which is in two symmetrical pieces. The screens are fabricated with the sameconical angle as the disc surfaces 46, the latter being machined (in a final step for accuracy) on discs 44 (which areeach cast in one piece with radial ribs 64 from Meehanite CC acid-resisting iron), so that accurate mating for field assembly is assured. Housing 42 (which includes an upper and a lower portion) includes therearound two sets 66 of labyrinth sealing grooves, each set cooperating with labyrinth sealing projections on one of the discs, to make practical use of the disc press With'tninner slurries. Integral with housing 42 is dependent doctor 70, the sides of which are spaced closely to the screens 62 of the rotating discs. Water lubrication is through holes 71 running at an angle from the wash chamber 72 and opening through the doctor 70 at its surfaces engaged by the screened discs. The doctor 70 includes three depending struts which define with the screens 62, a wash chamber 72 and a knot removal chamber 74. Knots carried by screens 62 into the chamber 74 are rubbed from said screens (FIG. 3) by auger 76 and outwardly moved by the same (rotated by motor 78) for ejection through opening 80 (from which they may be reintroduced, to be broken up, into the stock to be fed to the screw filter). Wash water introduced through pipe 82 to wash chamber 72 permits washing out directly through screens 62 without stopping operation or making disassembly. The bottom half of housing 42 carries washout drain 84. Fluid squeezed through screens 62 emerges through holes 48. Rate of rotation of discs 44 is varied by pressure sensor 85, mounted in inlet zone 40, which varies the speed of motor 58 to maintain a constant pressure in zone 40. The sensor 85 may for example be of the Consotrol M/SZA type sold by The Foxboro Company, Foxboro, Mass.

Exit zone 86 is above the area of greatest solids compression (which is along a horizontal plane through the horizontal centerline of the squeezing zone between the discs), so that the outcoming material is allowed to expand transversely as it is leaving. Also, because the zone 86 is thus positioned, the .outcoming product is free to expand upwardly, which it does, facilitating and cooperating with the action of shredder 90, which acts on the emerging bulk to break it into discrete small pieces well adapted for pneumatic transmission therefrom.

Shredder 90, which provides uniformity of discharge as well as pellet-sized output, provides 51,000 shredding edges 92 acting against the output solids per minute. Although diagrammatically shown in the drawings, these teeth with shredding edges 92 are in a preferred embodiment set at many different pitches, and are carried by a multiplicity of strands of chains running on sprockets 94 and driven by motor 96 through belt 98. Shredder 90 drives shredded cake away from discpress 12 at about 430 feet per minute. The chains bearing toothed edges 92 run on rolling bearings, and the entire shredder is pivotally mounted on the disc press, both for ease of access and as a safety measure in the event of drive failure to permit cake to emerge freely.

The operation of the apparatus will be apparent in what has already been said. When the discharge from screw filter, to disc press 12 is about 8% or more, the portion 32 is removed, so that exit may be through the zone therebeneath as well as through the zone otherwise available.

Other embodiments within the following claims will occur to those skilled in the art.

What is claimed is:

1. Liquid removing apparatus comprising a screw filter with an output zone,

a disc press having an input zone, horizontal axes of rotation, and e an output zone above said axes,

a pressure sensor in said input zone operative to vary the rate of rotation of the discs of the disc press to tend to keep constant the pressure in said input zone, and

a shredder above the press output zone, said shredder comprising a multiplicity of teeth rapidly and successively engaging the output of said press output zone.

2. The apparatus of claim 1 in which said disc press includes a central doctor downwardly dependent between said discs and in close proximity thereto, said doctor comprising a doctor surface and a pair of downwardly extending cavities defining with said discs and the screens thereover a wash chamber and a knot remover.

3. The apparatus of claim '2 in which said central doctor is an integral portion of a housing, said housing cooperating with each of said discs around the outer opposed peripheries thereof in labyrinth seals.

4.,The apparatus of claim 3 in which said filter includes a screw and a foraminous cylinder engaged by the outer helical surface of said screw, said outer helical surface being defined by a multiplicity of metal bristles, and in which said filter includes also inlet and outlet members, the axes of symmetry of said inlet and outlet members diverging in opposite directions from the axis of said screw.

5. A disc press comprising a pair of discs mounted for rotation about a pair of axes, said axes intersecting intermediate of said discs in an angle, said discs including facing frustoconical surfaces defining therebetween a pressing zone varying in thickness from a widest thickness in connection with an input zone to a narrowest thickness in connection with an output zone, and a doctor extending between said frustoconical surfaces radially thereof outside said pressing zone, and with transverse surfaces conforming closely with said frustoconical surfaces, said doctor including a radially extending opening in contact through said transverse surfaces with said discs, and a washing fluid supply line to said opening.

6. A disc press comprising a pair of screened discs mounted for rotation about a pair of axes, said axes intersecting intermediate of said discs in an angle, said discs including facing frustoconical surfaces defining therebetween a pressing zone varying in thickness from a widest thickness in connection with an input zone to a narrowest thickness in connection with an output zone, a doctor extending between said frustoconical surfaces radially thereof outside said pressing zone, and with transverse surfaces conforming closely with said frustoconical surfaces, said doctor including a radially extending opening in contact through said transverse surfaces with said screened discs, and a cleaner mounted in said opening, said cleaner being movable in contact with said screened discs to remove knots therefrom and into said chamber.

7. Liquid removing apparatus comprising a disc press with a pair of discs mounted for rotation about a pair of axes intersecting intermediate of said discs in an angle, said discs including facing frustoconical surfaces defining therebetween a pressing zone varying in thickness from a widest thickness in connectionwith an input zone to a narrowest thickness in connection with an output zone, and a shredder mountedat said output zone in spaced relation from said narrowest thickness, said shredder including a multiplicity of shredding surfaces moving rapidly at an angle to the direction of output in said output zone to discharge product in shreds at a different angle.

8. A disc press comprising a pair of discs mounted for rotation about a pair of axes, said axes intersecting intermediate of said discs in an angle, said discs including facing frustoconical surfaces defining therebetween a pressing zone varying in thickness from a widestthickness in connection with an input zone to a narrowest thickness in connection with an output zone, a housing cooperating with each of said discs around the outer opposed peripheries thereof in labyrinth seals, and a doctor extending between said frustoconical surfaces radially thereof outside said pressing zone, and with transverse surfaces conforming closely with said frustoconical surfaces, said doctor including a pair of radially extending openings each in contact through said transverse surfaces with said discs, said doctor being integral with said housing, one of said chambers being provided for access to washing fluid and the other of said chambers having mounted therein a cleaner for movement in contact with said discs to transfer knots therefrom into the last-mentioned chamber.

9. The press of claim '8 in which said cleaner is an auger mounted for rotation about a radial axis in contact with said screened discs to transfer knots therefrom and i move said knots radially from the chamber.

10. A disc press comprising a pair of screened discs mounted for rotation about a pair of horizontal axes, said axes intersecting intermediate of said discs in an angle, said discs including facing frustoconical surfaces defining therebetween a pressing zone varying in thickness from a Widest thickness in connection with an input zone to a narrowest thickness in connection with an output zone, a housing with peripheries cooperating with facing peripheries of said discs to provide labyrinth seals therearound, said housing including an integral downwardly and radially extending doctor with transverse surfaces conforming closely with said frustoconical surfaces, said doctor in cluding a pair of radially extending openings each in contact through said transverse surfaces with said screened discs, one of said chambers being provided for access to washing fluid and the other having mounted therein for rotation about a generally radial axis an auger contacting said screened discs, a variable speed motor for driving said discs jointly at selectively variable speeds, and a pressure sensor in said input zone, said pressure sensor signalling said motor to increase the speed thereof upon a rise in pressure and decrease the speed thereof upon a decrease in pressure to minimize pressure variation in said input zone.

11. Liquid removing apparatus comprising a screw filter with an output zone,

a disc press comprising a pair of discs mounted for rotation about a pair of axes intersecting intermediate of said discs in an angle, said discs including facing frustoconical surfaces defining therebetween a pressing zone varying in thickness from a widest thickness in connection with an input zone to a narrowest thickness in connection with an output zone, said input zone being in closed communication with said output zone of said screw filter whereby the fluid pressure at said input zone may be controlled, and

a pressure sensor responsive to rate of output through said output zone of said screw filter to decrease the speed of rotation of said discs upon a drop of said rate, whereby substantial reduction of pressure in said input zone is prevented.

References Cited UNITED STATES PATENTS 772,230 10/1904 Farner 100-145 1,630,430 5/1927 Holter 100-145 2,146,158 2/1939 Scherer 100116 X 2,327,448 '8/ 1943 Olive 10047 2,793,583 5/1957 Messing 100121 3,062,129 11/1962 Wandel 100-117 X 3,188,942 6/1965 Wandel 100117 X 3,218,963 11/1965 Ginaven 100121 ROBERT W. JENKINS, Primary Examiner.

Claims

1. LIQUID REMOVING APPARATUS COMPRISING A SCREW FILTER WITH AN OUTPUT ZONE, A DISC PRESS HAVING AN INPUT ZONE, HORIZONTAL AXIS OF ROTATION, AND AN OUTPUT ZONE ABOVE SAID AXES, A PRESSURE SENSOR IN SAID INPUT ZONE OPERATIVE TO VARY THE RATE OF ROTATION OF THE DISCS OF THE DISC PRESS TO TEND TO KEEP CONSTANT THE PRESSURE IN SAID INPUT ZONE, AND