US3035511A

US3035511A - Vertical screw press

Info

Publication number: US3035511A
Application number: US577696A
Authority: US
Inventors: Dudley W Hayes
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1956-04-12
Filing date: 1956-04-12
Publication date: 1962-05-22
Anticipated expiration: 1979-05-22

Description

May 22, 1962 11w. HAYES 3,0

VERTICAL SCREW PRESS Filed April 12, 1956 4 Sheets-Sheet l F'I I3 l IBQ |3l use 132 I35 INVENTOR DUDLEY W. HAYES ATTORNEY May 22, 1962 D. w. HAYES 3,035,511

' VERTICAL SCREW PRESS Filed April 12, 1956 4 Sheets-Sheet 2 2 INVENTOR DUDLEY W. HAYES M 0 BY AM 5.

ATTORNEY y 22, 1962 D. w. HAYES 3,035,511

VERTICAL SCREW PRESS Filed April 12, 1956 4 Sheets-Sheet 3 57 I 8)| 8O -55 5g 95 56 g2 63 O a? 55 O) 77 1 INVENTOR DUDLEY W. HAYES 1962 D. w. HAYES 3,035,511

VERTICAL SCREW PRESS Filed April 12, 1956 4 Sheets-Sheet O F I E El INVENTOR DUDLEY W. HAYES svwgr/ ATTORNEY United States Patent 3,035,511 VERTICAL SCREW PRESS Dudley W. Hayes, San Jose, Calif., assignor to FMC Corporation, a corporation of Delaware Filed Apr. 12, 1956, Ser. No. 577,696 15 Claims. (1. 100-117) This invention pertains to improvements in presses and more specifically relates to an improved continuous press of the screw type for the expressing of liquids from solids.

The improved press of the instant invention finds particular utility in paper and pulp mills for removing liquids from pulp, and in food processing plants for removing the juices from various fruits or vegetables, or from the waste products resulting from other processing of said fruits or vegetables.

One object of the invention is to provide a press wherein the effluent flows in a direction counter to the direction of the flow of the material being pressed.

Another object of the invention is to provide a press having a more eflicient and flexible control of the pressure exerted within the press than heretofore obtainable in presses of similar type.

Still another object of the invention is to provide a continuous press which is self-priming.

Other objects and advantages of the invention will become apparent from the following description and the accompanying drawings, wherein:

FIG. 1 is an elevation view of a press embodying the principles of the present.invention, with one-half of the outer screen removed and certain of the parts shown in section.

PEG. 2 is an enlarged vertical section of the upper portion of the machine shown in FIG. 1, the section being taken substantially on a diametrical plane with certain parts shown in elevation.

FIG. 3 is an enlarged vertical section of the lower portion of the machine shown in FIG. 1.

FIG. 4 is a horizontal section taken along line 44 of FIG. 1.

FIG. 5 is a horizontal section of FIG. 1 taken along line 55 thereof.

FIG. 6 is a horizontal section taken along line 66 of FIG. 3.

'FIG. 7 is a vertical section taken along line 77 of FIG. 6.

FIG. 8 is a section of a portion of FIG. 6 taken along line 88 thereof.

FIG. 9 is a schematic perspective showing the power train of the drive mechanism of the press.

In general the press illustrated in FIG. 1 comprises an outer screen 10 and a cone-shaped screw assembly 12 mounted coaxially therewithin. The material to be pressed is introduced to the press adjacent the bottom thereof by a conveyor 13. The material is moved up wardly through the press, between the outer annular screen 10 and the cone-shaped screw assembly 12, by rotation of the screw assembly. The liquid expressed through the screen 10 flows downwardly along the outer side thereof and is collected in an annular trough 14 surrounding the lower end of the screen. The solid material is expelled from the upper end of the screen 10 into an annular pan 15. The working pressure within the press is controlled by a choke assembly 16 which cooperates with the upper end of the screen 10 to restrict the flow of the solid material therefrom.

Referring now to FIGS. 1 and 2 of the drawings, a

rive housing 11 is supported on the upper ends of three

vertical standards

20, 21 and 22 which rest on the floor or any suitable base. A main gear 25, having a .hub 30 formed integral therewith, is rotatably mounted within the drive housing 11 by a pair of thrust bearings 26 and 27 (FIG. 2) mounted in

suitable bosses

28 and 29 formed in the housing.

Suitable packing elements

31 and 32, respectively, are interposed between each of the bosses 2S and 29 and the hub 30 externally of the

bearings

26 and 27 to prevent leakage of oil from the housing 11. A sleeve 33 is mounted within the hub 30 and keyed thereto by a key 34. The sleeve 33 extends downwardly from the housing 11 and is provided with an upwardly facing shoulder 35 abutting the lower end of the hub 30. A snap ring 36 is received in a suitable groove adjacent the upper end of the sleeve 33 and abuts the upper end of the hub 30 to lock the gear against axial movement on the sleeve. The lower end of the sleeve 33 is provided with an outwardly extending annular flange 37.

The cone-shaped screw assembly 12, previously mentioned, is fastened to the flange 37 of the sleeve 33 for rotation therewith by a plurality of cap screws 39 in the manner shown in FIG. 2. A disc 40 is interposed between the lower end of the sleeve 33 and the upper end of the screw assembly 12. The disc 40 is provided with a downwardly extending flange 41 and an upwardly extending flange 42 at its peripheral edge. The purpose of these flanges will be explained hereinbelow.

The screw assembly 12 comprises an upper frustoconical member 43 (FIG. 3) and a lower cylindrical member 44 fastened together, as by welding, in end-to-end relation in the manner shown in FIG. 3. As best seen in FIGS. 2 and 4, the outer surface of the upper member 43 of the screw assembly 12 is provided with a plurality of longitudinally extending grooves 45, and with V-shaped grooves 46 at four points equally spaced about the member 43 between the grooves 45. Two triangular-shaped flight-supporting rods 47 are received in each of the V-shaped grooves 46. The upper ends of the rods are disposed behind the flange 41 on the disc 40 (previously described), and the lower ends are locked in the V-grooves 46 by means of a clamp ring 48 shown in FIGS. 1 and 3. A plurality of helical flight members 49 are fixed to the bars 47 at spaced points therealong. Each of the flight members 49 extends approximately one quarter of the way around the periphery of the member 43, and each of the ends thereof is fixed to one of the rods 47 as seen in FIG. 1. The flights in one section tend to continue from the flights in the section next adjacent thereto to form a double helix extending the length of the member 43. However, the lowermost edge of the flights of one section are stepped vertically upward from the upper edge of the flights of the section next adjacent thereto to provide clearance for a plurality of breaker bars 50, more fully described hereinbelow. A section of screen material 51 (FIG. 4) is interposed between the inner edge of the flights 49 and the exterior surface of the member 43 and is held in this position by the flights 49. The outer edges of all of the flights 49 are equidistant from the axis of rotation of the screw assembly 12.

The lower cylindrical member 44 (FIGS. 3 and 5) of the screw assembly 12 is provided with two outwardly extending longitudinal flanges 52 each having a longitudinally extending groove 53 formed in its outer surface. A rod 54 is received in each of the grooves 53 and the upperend of the rod is held in the groove by the clamp ring 48, previously described, and the lower end by a clamp ring 48a. Two flights 55 are mounted one on each of the rods 54, and two semicylindrical screen sections 56 are interposed between the inner edges of the flights 55 and the member 44. Two outwardly extending longtiudinal ribs 57 are provided on the member 44 midway between the flanges 52 to support the mid-portions of the screen section 56.

The previously mentioned cylindrical outer screen assembly 10 surrounds the screw assembly 12 in coaxial relation therewith and the inner surface of the screen assembly 10 is substantially in sliding engagement with the outer edges of the

flights

49 and 55. The outer screen assembly 10 comprises two complementary semicylindrical sections 59 and 60 (FIG. 4). The

sections

59 and 60 are mirror images of each other and, therefore, only the section 59 will be described in detail.

As seen in FIGS. 4, and 6, the outer screen assembly section 59 comprises a rigid frame having three vertically extending

bars

61, 62 and 63. The

bars

61, 62 and 63 are held in their proper spaced positions, with the

rods

61 and 63 defining each of the edges of the section 59 and the rod 62 being disposed adjacent the mid-portion thereof, by a plurality of horizontally disposed semicircular ribs or braces 64 which are welded to each of the

bars

61, 62 and 63. The breaker bars 50, previously mentioned, are either cast integral with the ribs 64, as shownin FIG. 7, or suitably attached thereto and extend inwardly therefrom at the points on each of said ribs midway between the

bars

61 and 62 and midway between the

bars

62 and 63. When the screen assembly is installed, the bars extend between the ends of the individual flights 49. A semicylindrical section of screen material 65 is fastened in any suitable manner to the inner surface of the frame comprising the

rods

61, 62 and 63 and the circular ribs 64. The screen material 65 is provided with suitable openings, in the manner shown in FIG. 8, to permit the breaker bars 50 to protrude therethrough. It should, of course, be realized that the particular mesh size of the screen material 65 should be chosen according to the material to be processed in the press. It is contemplated that the screen may have openings as small as .025" when handling finely divided material.

As best seen in FIGS. 3 and 5, the vertical'bar 61 terminates short of the lower end of the screen section 59, and a semicircular member 66 connects the lower end of the member 61 with a flange 68 at the lower endge of the screen section 59. A semicircular opening 65a is cut in the'screen 65 and a semicircular screen 67 connects between the edges ofthe opening 651: in the screen 65 and the member 66. The member 66, together with its complemental member on the screen section 60, defines a circular inlet opening having its axis at right angles to the screen assembly 10 are mounted on a pair of

brackets

69 and 70 fixed to the vertical standard 20 at spaced points therealong and extending inwardly therefrom toward the axis of the screw assembly 12. Each of the

screen sections

59 and 60 are pivotally supported by the

brackets

69 and 70 by offset arms 71 so that each section may independently be swung from its closed position surrounding the screw assembly 12, to an open position exposing the screw assembly for cleaning or repair. When in. closed relation, the

screen sections

59 and 60 are latched together by a plurality of swing bolts 72 pivotally mounted on pins 73 extending between spaced laterally extending flanges 74 on one of the

vertical bars

61 or 63 of the

sections

59 or 60, and extending between spaced laterally extending flanges 75 on the opposing

bars

61 or 63 of the other of the

sections

59 or 60. The swing bolts 72 are held in their latching position by nuts 76 threaded thereon and abutting the lateral edges of the flanges 75.

As best seen in FIGS. .1, 3 and 5, the liquid expressed through the screen 10, flows downwardly along the outer side of the screen and is collected in the previously mentioned annular U-shaped trough 14 which, in turn, is provided with a discharge spout 85. The U-shaped trough 14 is mounted on a subframe generally indicated at 82 with its inner wall within the lower end of the circular screen assembly 10 and its outer wall spaced outwardly from the outer surface thereof.

As best seen in FIG. 5, the subframe 82 comprises a bracket 77 fixed to the vertical standard 20, a bracket 78 fixed to the vertical standard 21 and a bracket 79 (FIG. 3) fixed to the standard 22. A channel member 80 is fixed at its opposite ends to the

brackets

78 and 79 and a second channel member 81 is welded at one of its ends to the central portion of the channel member 80 and is fixed at its other end to the bracket 77.

Referring now particularly to FiG. 3, a sleeve 83 is fixed to the subframe 82 and extends upwardly therefrom in embracing relation with the lower end of the screw assembly 12 to form a guide therefor. A sleeve 86 is rotatably received within the sleeve 83 and is fixed to the lower end of the screw 12 in abutting relation with the lower end of the clamp ring 48a mounted thereon, and encloses the lower end portions of the grooves between the flanges 52 and the ribs 57, previously described. A flat annular screen member 87 closes the annular space between the upper ring of the inner wall of the annular trough 14, and the sleeve 86. An O-ring 88 is mounted adjacent the inner edge of the screen 87 in sealing engagement with the outer surface of the sleeve 86. A flat annular plate 89 is fixed to a flange 90 on the sleeve 83 and is welded to the inner side of the inner wall of the trough 14 as a point spaced downwardly from the screen 87. A suitable O-ring 91 is mounted adjacent the inner edge of the plate 89 in sealing engagement with the sleeve 86. A plurality of ports 92 in the sleeve 86 conmeet the spaces between the flanges 52 and the ribs 57 of the lower section 44 of the screw assembly 12 with the space between the screen 87 and the plate 89. Similarly, a plurality of ports 93, in the inner wall of the trough 14, connect the space between the screen 87 and the plate 89 with the interior of the trough 14. Thus, it can be seen that the eflluent forced inwardly through the

screens

51 and 56 on the screw assembly 12 will flow downwardly through the grooves 45 and the space between the flanges 52 and the ribs 57 and outwardly through the ports 92 and 93 into the collecting trough 14.

Referring now to FIGS. 1 and 2, the choke assembly 16, which, as previously mentioned, controls the discharge of the relatively dry material from the upper end of the annular space between the screw assembly 12 and the screen assembly 10, comprises a choke member having an upper cylindrical section 101 and a lower downwardly and inwardly tapered conical section 102. The conical portion 102 of the member 100 is adapted to be received within the upper end of the screen assembly 10 and the inner surface of the lower portion of the conical section 102 is in sliding contact with the outer surface of the upwardly extending annular flange 42 on the member 40 previously described in connection with the screw assembly 12. The choke member 100 is supported by a spider assembly 103 fixed to the inner surface of the cylindrical portion 101 and slidably mounted on the exterior of the lower portion of the sleeve 33, previously described. A pin 104 is fixed to the hub of the spider 103 and extends diametrically thereof through two opposed longitudinally extending slots 105 and 106 formed in the sleeve 33. Two rollers 107 and 108 are mounted on the pin 104 one within each of the slots 105 and 106, respectively. From. this structure it is evident that the choke member 100 rotates with the sleeve 33 and the screw assembly 12 attached thereto, but is capable of longitudinal movement with respect thereto to regulate the size of the discharge opening at the upper end of the screen assembly 10.

In order to provide the longitudinal movement of the choke member 100 to regulate the size of the discharge opening, a swivel head 109 is fixed to the central portion of the pin 104. The swivel head 109 is rotatably connected to the lower end of a shaft 110 by a suitable bearing 111. The shaft 110 extends upwardly through the sleeve 33 and is connected to the piston of a suitable hydraulic or pneumatic cylinder 112 rigidly mounted above the drive housing 11 in concentric relation with the sleeve 33 in the manner shown in FIG. 1. It is evident that when the cylinder 112 is actuated, the shaft 110 will be moved upwardly or downwardly relative to the sleeve 33 and the screw assembly 12 and thus will cause the choke member 100 to be moved outwardly or inwardly relative to the upper end of the screen assembly 19 to regulate the discharge of the solid material therefrom. It is further evident that the movement of the choke member 100 may be readily accomplished both when the press is operating and when it is not.

The relatively dry solids issuing from the upper end of the screen assembly 10 are guided laterally by the conical surface 102 of the choke member 100 into the previously mentioned annular pan 15 mounted adjacent the upper end of the screen assembly 10. The pan 15 has a bottom portion 114, the inner edge of which is provided with a depending annular flange 115 and an outer vertical side portion 116. A discharge chute 117 is formed integral with the pan 15. The pan 15 is supported by a plurality of similar brackets fixed to the

vertical column

20, 21 and 23, respectively. Only one of the brackets is shown at 118 in FIGS. 1 and 2 of the drawings. The bracket 118 is bolted to the vertical wall 116 of the pan 15 by suitable bolts 119 threaded into suitable holes in the wall 116. It can be seen that by proper selection of the points at which the threaded holes in the wall 116 are located, the discharge chute 117 may be selectively located in any orientation relative to the remainder of the machine. The depending annular flange 115 on the inner edge of the bottom 114 f the pan 15 is embraced by an upwardly extending annular rim 126 formed integral with a semicircular member 121 at the upper end of each of the

sections

59 and 66 of the screen assembly 12.

As best seen in FIG. 2, a plurality of paddle members 122 are fixed to the sleeve 33 between the upper end of the choke member 1530 and the lower portion of the drive housing 11. Each of the paddle members 122 has a horizontally extending arm 123 which extends outwardly beyond the choke member 190, and a downwardly depending paddle 124, connected to the outer end thereof. The paddle 124 substantially conforms to the cross sectional configuration of the interior of the pan 15, whereby, as the solid material is expelled from the upper end of the screen 19 into the pan 15 by the cone surface 1112 of the choke member 190, the paddles move the material thus expelled around the pan 15 and into the discharge chute 117.

The drive mechanism for rotating the screw assembly 12 is best illustrated in FIG. 9 and comprises a motor 13% mounted on a base plate 131 adjustably connected to a vertical bracket 132 fixed to the upper surface of the drive housing 11 in the manner shown in FIG. 1. Referring again now to FIG. 9, the motor 130 has fixed thereto a pulley 133 connected by a belt drive 134 to a pulley 135 fixed to a vertically disposed shaft 136 rotatably mounted in the drive housing 11 and extending upwardly therefrom. Within the drive housing 11, a spur gear 137 on the shaft 136 drives the main gear 25, previouay mentioned, through a reduction gear

chain comprising gears

138, 139, 140 and 141.

In operation of the press, the motor 139 is started to commence the rotation of the screw assembly 12, and the feed conveyor 13 is started to feed the material to be pressed into the annular space between the screw assembly 12 and the outer screen assembly 19. The

flights

55 and 49 urge the material upwardly between the screw and the screen. Due to the conical shape of the upper section 43 of the screw assembly 12, the cross sectional area of the annular space between the screw assembly 12 and the screen 10 is progressively reduced and therefore the material is compressed. The liquid content of the material is expressed outwardly through the screen 10 and flows down the outer surface thereof and is collected in the trough 14. Some of the fluid is expressed inwardly through the

screens

51 and 56 on the screw assembly 12 and flows downwardly through the grooves -35 and ultimately into the trough 14 in the manner heretofore described.

The relatively dry solid material is expelled from the top of the screen It) and forced outwardly into the pan 15 by the cone surface 102 of the choke member 100. The amount of pressure applied to the material is readily controlled by moving the choke member toward and away from the upper end of the screen assembly 10 by proper manipulation of the hydraulic or pneumatic cylinder 112. As can be plainly seen, the choke may readily be moved to change the pressure applied to the material while the press is operating.

Since the material travels vertically upwardly through the machine, the liquid flowing downwardly over the outer surface of the screen 10 is moving away from the previously pressed material and does not tend to rewet the material as in prior vertical presses wherein both the dry solids and the liquid are discharged from the bottom of the press.

Further, since the material travels upwardly against the pull of gravity, it is not usually necessary to prime the press by completely closing the choke 16 to initially build up a plug of dry solids when starting the press.

While I have shown and described the preferred embodiment of my invention, it is obvious that various changes may be made therein without departing from the spirit of the invention as defined in the appended claims.

Having thus described my invention what I claim and desire to secure by Letters Patent is:

1. In an expressing press, an outer cylindrical screen mounted with its axis vertical, a drive housing mounted above the upper end of said screen, a downwardly and inwardly tapered cone rotatably supported from said drive housing and extending downwardly therefrom coaxially within said cylindrical screen, a plurality of longitudinally extending grooves formed in the outer surface of said cone, a plurality of flight sections fixed t said cone, and screen sections between the inner edges of said flight sections and said cone and covering said grooves.

2. In an expressing press, an outer cylindrical screen mounted with its axis vertical, a drive housing mounted above the upper end of said screen, a downwardly and inwardly tapered cone rotatably supported from said drive housing and extending downwardly therefrom coaxially within said cylindrical screen, a plurality of longitudinally extending grooves formed in the outer surface of said cone, a plurality of longitudinally extending bars removably secured in certain of said grooves, a plurality of flight sections fixed to said bars, and screen sections between the inner edges of said flight sections and said cone and covering the remainder of said grooves.

3. In an expressing press, an outer cylindrical screen mounted with its axis vertical, a drive housing mounted above the upper end of said screen, a downwardly and inwardly tapered cone rotatably supported from said drive housing and extending downwardly therefrom coaxially within said cylindrical screen, a plurality of longitudinally extending grooves formed in the outer surface of said cone, a plurality of longitudinally extending bars removably secured in certain of said grooves, a plurality of flight sections fixed to said bars, screen sections between the inner edges of said flight sections and said cone and covering the remainder of said grooves, an annular trough surrounding the lower end of said outer screen for collecting the liquid expressed therethrough and flowing down the outer side thereof, and means connecting the lower ends of the grooves in said cone with said trough for collecting the liquid expressed inwardly through the screen sections on said cone.

4. In an expressing press, an outer cylindrical screen mounted with its axis vertical, a drive housing mounted.v

, tween the inner edges of said flight sections and said cone and covering the remainder of said grooves, an annular trough surrounding the lower end of said outer screen for collecting the liquid expressed therethrough and flowing down the outer side thereof, means connecting the lower ends of the grooves in said cone with said trough for collecting the liquid expressed inwardly through the screen sections on said cone, a downwardly and inwardly inclined cone-shaped choke, the lower end of said choke being in sliding engagement with the upper portion of said cone adjacent the upper end of said outer screen, and means for moving said choke longitudinally of said cone to adjust the pressure within the press.

5. In an expressing press, an outer cylindrical screen mounted with its axis vertical, a .drive housing mounted above the upper end of said screen, a downwardly and inwardly tapered cone rotatably supported from said drive housing and extending downwardly therefrom coaxially within said cylindrical screen, a plurality of longitudinally extending grooves formed in the outer surface of said cone, a plurality of longitudinally extending bars removably secured in certain of said grooves, a plurality of flight sections fixed to said bars, screen sections between the inner edges of said flight sections and said cone and covering the remainder of said grooves, an annular trough surrounding the lower end of said outer screen for collecting the liquid expressed therethrough and flowing down the outer side thereof, means connecting the lower ends of the grooves in said cone with said trough for collecting the liquid expressed inwardly through the screen sections on said cone, a downwardly and inwardly inclined cone-shaped choke, the lower end of said choke being in sliding engagement with the upper portion of said cone adjacent the upper end of said outer screen, means for moving said choke longitudinally relative to said cone, and means for feeding material to be pressed to the annular space between said cone and said outer screen adjacent the lower end thereof.

6. In an expressing press, a cylindrical screen, a drive housing mounted adjacent one end of said screen, a sleeve mounted for rotation in said drive housing and extending therefrom coaxial with and toward said screen, a tapered screw mounted on the end of said sleeve and extending therefrom coaxially within said cylindrical screen, a cone-shaped choke slidably mounted on said screw with its smaller end disposed toward and adjacent the said one end of said screen, a fluid actuated cylinder mounted on the side of said drive housing away from said screen in coaxial relation with said sleeve, a piston in said cylinder, a piston rod connected to said piston and extending within said sleeve, a diametrically disposed rod swivelly connected at its central portion to the end of said piston rod, and a pair of longitudinally extending diametrically opposed slots in said sleeve, said diametrically disposed rod extending through said slots and being connected at its outermost ends to said choke.

7. In an expressing press, a cylindrical screen mounted with its axis vertical, a drive housing mounted above the upper end of said screen, a sleeve mounted for rotation in said drive housing-and extending downwardly there from, a downwardly and inwardly tapered screw mounted on the lower end of said sleeve and extending downwardly therefrom coaxially within said cylindrical screen, a shaft extending downwardly within said sleeve, a diametrically disposed rod swivelly connected to the lower end of said shaft, a pair of longitudinally extending diametrically opposed slots in said sleeve, said diametrically disposed rod extending through said slots, a downwardly and inwardly inclined cone-shaped choke fixed to the outer ends of said diametrically disposed rod, the lower end of said choke being in sliding engagement with the upper portion of said screw member adjacent the upper end of said screen, and means for moving said shaft longitudinally to move said choke relative to the upper end of said screen.

8. In an expressing press, a cylindrical screen mounted with its axis vertical, a drive housing mounted above the upper end of said screen, a sleeve mounted for rotation in said drive housing and extending downwardly therefrom, a downwardly and inwardly tapered screw mounted on the lower end of said sleeve and extending downwardly therefrom coaxially within said cylindrical screen, a fluid actuated cylinder mounted above said drive housing in coaxial relation with said sleeve, a piston in said cylinder, a piston rod connected to said piston and extending downwardly within said sleeve, a diametrically disposed rod swivelly connected to the lower end of said piston rod, a pair of longitudinally extending diametrically opposed slots in said sleeve, said diametrically disposed rod extending through said slots, a downwardly and inwardly inclined cone-shaped choke fixed to the outer ends of said diametrically disposed rod, the lower end of said choke being in sliding engagement with the upper portion of said screw member adjacent the upper end of said screen.

9. In an expressing press, a cylindrical screen mounted with its axis vertical, a drive housing mounted above the upper end of said screen, a sleeve mounted for rotation in said drive housing and extending downwardly there from, a downwardly and inwardly tapered screw mounted on the lower end of said sleeve and extending downwardly therefrom coaxially within said cylindrical screen, a fluid actuated cylinder mounted above said drive housing in coaxial relation with said sleeve, a piston in said cylinder, a piston rod connected to said piston and extending downwardly within said sleeve, a diametrically disposed rod swivelly connected to the lower end of said piston rod, a pair of longitudinally extending diametrically opposed slots in said sleeve, said diametrically disposed rod extending through said slots, a pair of rollers rotatably mounted on said rod, one of said rollers being located in each of said slots, a downwardly and inwardly inclined cone shaped choke fixed to the outer ends of said diametrically disposed red, the lower end of said choke being in sliding engagement with the upper portion of said screw member adjacent the upper end of said screen.

10. For use in an expressing press, a screw assembly comprising, a truncated cone-shaped member, a cylindrical member connected to the smaller end of said cone member in coaxial relation therewith, a plurality of longitudinally extending grooves in the outer surface of each of said members, the grooves on one of said members being in end-to-end communication with the grooves on the other of said members, a plurality of flight sections fixed to each of said members, and screen sections between said flight sections and each of said members, said screen sections covering said grooves.

11. For use in an expressing press, a screw assembly comprising, a truncated cone-shaped member, a cylindrical member connected to the smaller end of said cone member in coaxial relation therewith, a plurality of longitudinally extending grooves in the outer surface of each of said members, a plurality of longitudinally extending bars removably secured in certain of the grooves on each of said members, a plurality of flight sections fixed to said bars, and screen sections between said flight sections and each of said members, said screen sections covering the remainder of said grooves.

12. In an expressing press, an outer cylindrical screen, a drive housing mounted above the upper end of said screen, a downwardly and inwardly tapered cone rotatably supported from said drive housing and extending downwardly therefrom coaxially within said cylindrical screen, a plurality of longitudinally extending bars removably secured to said cone, a plurality of material lifting flight sections fixed to said bars, and drive means disposed in said housing and connected to said cone to rotate said cone in a direction causing said flights to lift material upwardly within said outer screen.

13. For use in an expressing press, a screw assembly comprising, a truncated cone-shaped member, a cylindrical member connected to the smaller end of said cone member in coaxial relation therewith, means defining a plurality of flow passages extending longitudinally along the surfaces of said cone member and said cylindrical member, a plurality of longitudinally extending bars removably secured to said cone member, a plurality of flight sections fixed to said bars, and screen sections between said flight sections and each of said members and covering said flow passages.

14. In an expressing press, a support structure, a cylindrical screen on said structure, a drive housing mounted adjacent one end of said screen, a drive sleeve mounted for rotation in said drive housing and extending therefrom coaxial with and toward said screen, a tapered screw disposed adjacent the end of said sleeve and extending therefrom coaxially within said cylindrical screen, means securing the larger end of said screw to said sleeve for rotation therewith, a cone-shaped choke slidably mounted on said sleeve with its smaller end disposed toward and adjacent said one end of said screen, a fluid actuated cylinder mounted in fixed position on said support structure on the side of said drive housing away from said screen in coaxial relation with said sleeve, a piston in said cylinder, a piston rod disposed coaxially within said sleeve and extending from said fixed cylinder toward said screen,

said piston rod having one end connected to said piston, and means operatively associated with the other end of ,said piston rod extending radially outwardly therefrom for connecting said piston rod to said choke, whereby admission of fluid into said fixed cylinder effects sliding movement of said choke on said drive sleeve as said piston rod moves within said sleeve.

15. In an expressing press, a support structure, an outer cylindrical screen mounted on said structure with its axis vertical, a drive housing mounted above the upper end of said screen, a sleeve mounted for rotation in said drive housing and extending downwardly therefrom, a downwardly and inwardly tapered screw mounted on the lower end of said sleeve and extending downwardly therefrom coaxially within said cylindrical screen for feeding material upwardly through the press, said screw cooperating with said screen to define an annular processing chamber extending from a lower inlet zone to a relatively small upper discharge zone, means for introducing material to said lower inlet zone between said screw and said screen adjacent the lower ends thereof whereby said screw moves the material upwardly through said chamber and discharges the solids from said discharge zone at the upper end of said screen, a choke adjustably mounted on said sleeve adjacent said upper discharge zone of said processing chamber, and means for adjustably moving said choke.

References Cited in the file of this patent UNITED STATES PATENTS 488,956 Sobotka et a1. Dec. 27, 1892 731,734 Anderson June 23, 1903 742,971 Cummer Nov. 3, 1903 1,354,528 Wertenbruch Oct. 5, 1920 2,340,009 Meakin Jan. 25, 1944 2,419,545 Gray et a1 Apr. 29, 1947 2,709,957 Armstrong June 7, 1955 2,747,499 Beeman 7 May 29, 1956