US3447450A - Continuous press - Google Patents

Description

v June 3, 1969 D. M. WILHELM A 3,447,450

CONTINUOUS PRESS DONALD M. WILHELM F|G 1 gx@ Q.

ATTORNEYS June 3, 1969 D. M. WILHELM 3,447,450

CONTINUOUS PRESS Filed sept. 22, 1966 sheet Z FIG-3 INVENTOR. DONALD M. WILHELM ATTORNEYS D. M. WILHELM CONTINUOUS PRESS June 3, 1969 Sheet Filed Sept. 22, 1966 INVENTOR.' DONALD M. WILHELM BY @d4 J ./,lfi

nula

ATTORNEYS June 3, 1969 D. M. WILHELM 3,447,450

CONTINUOUS PRESS Sued sept. 22, 1966 1 sheet 4 of 5 INVENTOR. \Y DONALD M. WILHELM MUM ATTORNEYS June 3, 1969 Filed Sept. 22. 1966 D. M. WILHELM CONTINUOUS PRESS Sheet 5 of 5 ENT@ WILH M ATTORNEYS DONALD United States Patent O 3,447,450 CGNTINUOUS PRESS Donald M. Wilhelm, Novato, Calif., assignor to Rietz Manufacturing Co., Santa Rosa, Calif., a corporation of California Filed Sept. 22, 1966, Ser. No. 581,205 Int. Cl. B30b 9/06, 3/04 U.S. Cl. G-116 6 Claims ABSTRACT 0F THE DISCLOSURE This invention relates generally to presses of the continuous type such as are employed for extracting water or other liquids from various fluid or semi-fluid feed materials. The invention is particularly applicable to extracting water from various pulps, slurries, or other semisolid materials, including for example paper pulps, sewage sludges, vegetable and fruit pulps, tomato and grape pomace, citrus peel, iish or iish processing slurries, Cannery wastes, and brewers and distillers grains.

Presses for extracting liquids from feed materials employ filter screens adjacent which the solids of the feed are compressed to cause liquid to be expelled through the screen. They are made for both batch and continuous operations. One continuous press which has been used commercially employs a pair of rotating wheels or disks faced with screens shaped to conform to truncated cones. The axes of rotation of the wheels are intersecting but out of alignment whereby the screens are brought into close opposition in a pinch region, but separated apart a substantial distance in a region diametrically opposite the pinch region, thereby providing a feed receiving space into which the feed is continuously introduced. The two wheels are driven continuously in the same direction, usually by gear pinions on a common drive shaft which mesh with gear teeth provided on the peripheries of the wheels. A casing extends between the peripheries of the wheels and is provided with an inlet through which feed can be introduced into the feed receiving space, and also an outlet for the removal of expressed liquid. When a continuous supply of feed material is introduced into the feed receiving space, while the wheels are being rotated, the feed is carried continuously through the pinch region with the result that solids are squeezed between the adjacent portions of the screen and liquid caused to be expressed through the screen. Means is also provided for continuously removing expressed or dewatered solids from a region immediately following the pinch region. During the operation of such a continuous press, the location of the wheels remains fixed, and therefore the spacing of the screens in the pinch region remains constant.

Continuous presses of the type described above are subject to a number of disadvantages. The performance and capacity of such a press is dependent upon the rate of feed and also upon variations in the solids content of the feed material. This is because the pressure applied to the solids in the pinch region varies with the amount of solids present, and this in turn is dependent upon the rate of feed and the solids content of the feed. In many instances this has the effect of decreasing the over-all capacity of the machine, and in addition it interferes with attainment of a desired residual liquid content in the expressed solids and in the maintenance of a desired residual liquid content over long operating periods. The means described above for driving the wheels is unsatisfactory because misalignment of the wheels causes misalignment of the intermeshing gear teeth, with resulting excessive wear. Also the means generally employed to take the thrust against the wheels, namely thrust rollers tracking on the outer faces of the Wheels, is unduly complicated and unsatisfactory. Aside from the foregoing disadvantages, such prior continuous presses have not been amenable to quick adjustments to accommodate different types of feed materials, and their design has not facilitated ready access to the screens for replacement or repair, or for cleaning.

In general it is an object of the present invention to provide a continuous press which will overcome the disadvantages of prior continuous presses as outlined above.

More specifically, it is an object of the invention to provide a continuous lilter press which will maintain substantially constant pressing force upon the solids in the pinch region of the screens.

Another object of the invention is to provide a continuous press which will provide continuously discharging expressed solids of substantially constant liquid content, irrespective of variations in the solid content of the feed or in the rate of feed.

Another object of the invention is to provide a continuous press capable of relatively high capacity and satisfactory performance under a variety of conditions.

Another object of the invention is to provide a continuous press having improved means for driving the screen mounting wheels, whereby maintenance due to breakage or excessive wear is reduced to a minimum.

Another object of the invention is to provide a continuous press in which the thrust against the screens is taken by relatively simple means.

Another object of the invention is to provide a continuous press which permits ready access to the screens for making replacements or repairs, or for cleaning.

Additional objects and features of the invention will appear from the following description in which the preferred embodiments have been set forth in detail in conjunction with the accompanying drawing.

Referring to the drawing:

FIGURE 1 is a side elevational view showing a continuous press in accordance with the present invention;

FIGURE 2 is a plan View of the press shown in FIG- URE l;

FIGURE 3 is an end elevation, partly in section, looking toward the rear end of the machine;

FIGURE 4 is a cross-sectional view taken along the line 4 4 of FIGURE 3;

FIGURE 5 is a cross-sectional view taken along the line 5-5 of FIGURE 4;

FIGURE 6 is a schematic view elevation illustrating the hydraulic device connected to the side structures and also the apparatus for supplying hydraulic liquid under pressure to the same;

FIGURE 7 is a quarter view looking toward the inner side of the wheel;

FIGURE 8 `is a cross-sectional view taken along the line 9-9 of FIGURE 7;

FIGURE 9 is a cross-sectional view taken along the line 9*9 0f FIGURE 7;

FIGURE v10 is a development of a part of the rim of the wheel; and

FIGURE ll is a det-ail showing thrust bearing means `and also means for sealing the wheels with respect to adjacent wall portions of the casing.

The present invention employs a pair of rotating Wheels faced with screens shaped to conform to truncated cones. The axes of rotation are intersecting but out of alignment whereby the screens are in close apposition in a pinch region. Instead of maintaining a constant spacing between the screens in the pinch region during operation of the machine, the Wheels are mounted in such a manner that 4the screen portions in the pinch region are urged toward each other by a substantially constant but yieldable force. Thus substantially constant compression is maintained on 4the solids in the pinch region, irrespective of the quantity of solids present. In addition to the foregoing, the invention provides an improved chain drive fto the two wheels in place of the previously employed gear drive. Thrust against the wheels is taken by simple thrust bearing means disposed between annular areas of the wheels and adjacent annular areas of the side structures upon which the wheels are journalled. The machine is also constructed whereby the side structures upon the wheels are journalled can be swung outwardly a substantial distance, thus permitting ready access to the screens for repair or replacement, or for cleaning.

Referring to FIGURES 1 and 2, the machine in general consists of a suitable frame which supports the operating parts. Hopper 11 receives feed material, and the discharge of extracted solids is carried away by a conveyor 12. A suitable motor driven drive means `13 serves to drive the wheels of the press. Device 14 schematically represents an adjustable speed drive for delivering feed material. The machine includes the side structures 16 which are relatively strong and rigid and which can be made by metal fabrication. The general shape of each structure is such as to provide the rearward extension 17 and 18, and the forward extension 19. The rear extensions 17 and 18 are pivotally carried by the base of the machine. Thus as shown in lFIGURE 3 the upper extension 17 of each side structure is provided with a bracket 21 which is pivoted by pin 22 to the plate 23 forming a part of the machine frame. Similarly the bracket 24 is attached to the extension 18 and is connected by pivot pin 26 to the support plate 27. The pivot pin 22 and `26 are in vertical alignment.

It will be evident that the side structures 16 are `free tto swing about the vertical axis of the pins -22 land 26. Such movements may take place during operation of the machine or when it is desired to make repairs or replacement of the screens, at which time the structures 16 may be swung aparta substantial distance.

The forward extensions 19 of the side structures are connected together by a device 31 which is adapted to urge the structures together with yieldable but substantially constant force. The amount of .this force may be adjusted in accordance with operating conditions. In practice we have used a device 31 in the form of a piston and cylinder assembly supplied with hydraulic liquid under pressure. The `device 31 as illustrated is a cylinder with an inner movable piston, the piston being connected to the rod 32. `One end of the cylinder has an articulated connection by pin 33 to the lug 34 on the adjacent extension 19. Rod 32 is partially secured to the extension 19 of the other side structure. A pipe or hose 36 connects with the cylinder and with a suitable source of liquid under pressure. For this purpose it is convenient to use the apparatus illustrated in FIGURE 6. It consists of a small manually operated high pressure pump 37 which has its suction side connected to a convenient reservoir containing hydraulic liquid. The discharge piping 38 connects with the hose 36 and also with the visual pressure gauge 39 and the accumulator 41. The accumulator is of the type utilizing a pressure loaded piston or exible bladder loaded by gas under pressure introduced into the upper end of the same. Gas loading may be through the fit-ting 42 and to the pressure values indicated by gauge 43. -Normally the loading of lthe accumulator is set at a value which is known to be satisfactory for given operating conditions. The pump 4 37 is operated to ensure a substantial amount of oil in the accumulator, and the accumulator then maintains this pressure within the cylinder and piston assembly 31, thereby urging the extensions 19 of the side structures together with substantially constant by yieldable force.

Both of the extensions 19 overlie a horizontal plate 44 which is carried by the machine frame. Normally one extension is secured -to plate 44 by bolt 45a. The other extension 19 is loosely retained by a screw 45b, which extends through a slot in plate 44 whereby the extension and corresponding side structure 16 are free to move horizontally a limited amount.

The two wheels 46 are carried adjacent the inner sides of the two side structures v16 and fare disposed to rotate in generally vertical but non-parallel planes. 'Ihe construction of each wheel can best be understood by referring to FIGURES 7-ll. IParticularly, each wheel consists of a casting or fabricated structure 47 which is formed to mount 4the filter screen and also to provide cavities for receiving liquid expressed from the feed solids. Also it is provided with ribs for proper strength and to mount and support the screen. The structure 47 consists of a hub 48 and an outer rim 49. Rib-like spokes 51 extend between the hub 48 and the rim 49. Between these spokes there are shorter ribs 52 which extend `from the rim 49 to the ring 53. Openings 54 are provided in the ribs 52 for free movement of liquid. 'Similar openings 55 are provided in the spokes 51. An annular plate 57 is secured to the outer side of the wheel casting, and its periphery is provided with sprocket teeth 58. The central portion of plate 57 is secured to the hub 59 which in turn carries the stud shaft 61. The inner end of hub 48 is closed by plate l62.

The outer rim 49 of each wheel is provided with a plurality of circumferentially spaced openings 63 for free discharge in liquid. Also the rim is machined to provide the grooves 64 and 65 for purposes to be presently described.

A screen assembly 67 is secured by suitable means to the inner face of each wheel. This screen assembly is in the form of a truncated cone, and extends radially from the hub 48 of each wheel to the periphery of the rim 49. Preferably the screen consists of two parts, one being a perforated support provided with relatively large openings, and the second being a screen having relatively smaller perforations. In FIG. l1 the support and screen are designated as 67a and 67b. Note that the support 67a is relatively thick so that it has sufficient strength to support the lighter screen 67b.

The mounting of each wheel upon its associated side structure is as follows. Each side structure (FIGURE 3) is provided with a bearing insert or sleeve 69 which serves to journal the associated stud shaft 61. A retention nut or ring 70 is secured to the projecting end of shaft 61 to maintain the same within the bushing 69. During operation of the machine considerable thrust must be applied by the side structures to their associated wheels. To carry this thrust without occasioning undue friction, I provide segments of a thrust bearing annulus 71 made of suitable non-metallic material having good characteristics such as Teflon or nylon. This annulus may be attached to the plate 57 near the outer periphery of the sarne and bears upon an annular area of the adjacent side structure. One or more lubricant ttings 72 can be provided.

The two Wheels are positioned Within the sides of a casing 76. This casing generally surrounds the space between the screens and serves to receive feed material and to direct the feed material whereby it passes through the so-called pinch zone. A suitable seal is provided between the periphery of each Wheel and the adjacent wall portion 76a of the casing. Thus a resilient insert of wear ring 77 (FIGURE 1l) made of suitable material such as brass is fitted Within the groove 64 and has its outer periphery pressed into sealing contact with the peripheral surface 78 formed on the Wall portion 76a. The groove 65 is fitted with a splash or flip-off ring 79 which serves to prevent liquid from contacting the sprocket teeth.

As shown particularly in FIGURE 5, the structure 76 is provided with an opening 81 through which feed material is introduced and also an opening 82 through which the solids are discharged after liquid has been expressed from the same. A tapered barrier or plow structure 83 extends from one portion of the casing 76 to the vicinity of the hubs 48 of the wheels and serves as a plow to cause solid material to be delivered upwardly to suitable discharge means. The structure 83 can consist of tapered members 83a and 83b attached at their outer ends to the casing 76 and connected by a reinforcing web 84. The discharge means may consist of a suitable conveyor of the chain or screw type located within the discharge device. Member 83b extends from the upper edge of the inlet 81 to the Vicinity of the hubs of the wheels and serves as a barrier to direct the inowing feed material downwardly. A central stationary ring 85 is carried by the inner ends of members 83a and 83b and serves as an inner conning wall.

The means employed for delivering the feed material through the inlet opening 81 may consist of a shell 86 which encloses the feed screws 87. The feed screws serve to deliver the feed material from the hopper 11 through the inlet opening 81. A suitable liquid collecting container 91 extends below the casing 76 and below the wheels. It receives liquid draining through the holes 63 in the rims 49 of the wheels. Liquid can be drained from the container 91 through the opening 92.

The drive means illustrated (FIGURE 3) consists of a drive shaft 93 provided with drive sprockets 94. Chains 95 connect these sprockets with the sprocket teeth 58 on the wheels. These chains are made with substantial tolerances whereby the tensioned strands may twist to accommodate sprocket misalignment of the order of 6. Another sprocket 96 on shaft 93 is connected by a chain to the adjustable speed motor driven drive means 13. With this arrangement it has been found that the wheels are driven efciently without undue wear irrespective of the angular relationship of the sprocket wheels. When it is desired to have access to the screens, the chains are removed to permit the side structures and the wheels to be swung outwardly suciently far for easy access.

Operation of the continuous press is as follows. Normally the hydraulic device 31 is supplied with hydraulic liquid under a pressure which is known to be suitable for the service intended. Because of the capacity of the accumulator 41, this pressure remains substantially constant and is not increased to any substantial extent when sufficient thrust is applied to the side structures to cause some liquid from the device 31 to be returned to the accumulator. Assuming that the machine has not been started, the wheels assume a position as shown in FIG- URE 4. It will be noted that the left hand portions of the screens nearest the hydraulic unit 31 are in relatively close apposition. This is in what may be termed the pinch zone. At the opposite sidev of the machine nearest the pivoted axes of the side structures, the screens are separated apart a maximum distance, thereby forming a feed receiving space 97 into which the feed material is introduced. Assuming now that the machine is placed in operation with the wheels `being driven at a constant speed and with a feed material being supplied into the spaced 97, the material is carried downwardly (assuming clockwise rotation as viewed in FIGURE and as it approaches the pinch zone it is squeezed whereby expressed liquid flows through the screen into the cavities of the wheels. Within the pinch zone, which is on the left hand side of FIGURE 5, the compression is at a maximum. As the expressed solids are carried upwardly and toward the plow 83, the pressure is released and the material upon striking the plow 83 is deflected upwardly and discharged. Assuming that the rate of feed remains constant and that the percentage solids in the feed is likewise constant, then the spacing between the screens in the pinch zone remains substantially constant and the compression applied to the material by virtue of the hydraulic pressure applied to unit 31 is likewise constant. In many instances, however, the rate of feed varies from time to time, and in addition there may be variations in the solids content of the feed. Under such conditions, the amount of solids between the screens in the pinch zone varies, and such variations are accommodated by changes in the spacing between the screens. Such variations in spacing necessarily involved a change in the positioning of the wheels as accommodated by relative movement between the side structures and the hydraulic device 31. In other words, the force applied by the device 31 to the side structures and thence to the wheels is yielding -but substantially constant, and this permits changes in the relative positioning of the wheels and in the spacing between the screens in the pinch zone to accommodate the variations previously described. Although relatively heavy thrust is applied to the wheels, they are properly supported upon the side structures, and pressure tending to cause the wheels to cock with respect to the side structures is taken by the thrust bearing 71. As previously explained, the chain drive to the wheels accommodates the angularity of the wheels without causing excess wear. Thus maintanance of the driving parts is reduced to a minimum. When it is desired to clean out the interior parts of the machine, or remove the screens for repair or replacement, the drive chains are removed from the wheels, and then the hydraulic device 31 is disconnected by removal of pin 33, and the two side structure swung apart to permit complete access to the interior.

The feed is introduced at a point just above the region where the press wheels are farthest apart. Thus when this region is kept continuously lled by the feed material, maximum possible compression ratios are provided for a given spacing between the wheels in the pinch zone. Also the pinch zone is located at the horizontal center line of the wheels. This prevents reabsorption of expressed liquid by the solids as pressing pressures are being relieved, such as might occur if the pinch zone were located at a lower level.

I claim:

1. In a continuous press for extracting liquid from liquid containing feed materials, a main machine frame, a pair of rigid side structures, means serving pivotaly to carry the rear end portions of the structures on the frame whereby such structures may be moved toward or away from each other, a pair of opposed wheels journalled respectively to the structures on intersecting axes, each wheel including a conical shaped screen covering the inner side face of the same and an annular plate forming the outer side of the wheel, means interconnecting the other ends of the side structures, said last means serving to apply yieldable force to urge the side structures and the wheels toward each other, the axes of the wheels during operation -being out of alignment whereby when the wheels are rotated portions of the screens are brought into proximity in a pinch zone and other portions of the screen are separated to form a feed receiving space, thrust bearing means interposed between the outer margins of said annular plates and said side structures casing means serving to enclose the space between the wheels and having an opening for introducing feed material into the aforesaid feed receiving space, means for driving the wheels in the same direction whereby feed introduced into the feed receiving space is progressively squeezed as it is carried through the pinch zone, and means for removing extracted solids from between the screens.

2. A continuous press as in claim 1 in which each side structure has spaced upper and lower rear extensions and a single forward extension, said means for pivotally carrying said structures comprising pivotal connections between said rear extensions and the machine frame 7 whereby the structures may pivot about substantially parallel spaced axes, said means interconnecting the other ends of the side structures being connected to said forward extensions.

3. A continuous press as in claim 1 in which the drive means for said wheels consists of sprocket teeth on the peripheries of said annular plates, a driven shaft located alongeside the wheels, sprockets on said shaft, and drive chains connecting the drive sprockets with the sprocket teeth on the wheels, one run of each chain being adjacent and substantially parallel to the pivotal axis of the corresponding side structure, said chains permitting angular movements of the wheels relative to each other during operation of the press.

4. A continuous press as in claim 2 in which the means for applying yieldable force to the side structures consists of a hydraulic device located between said forward extensions of the side structures and connected thereto.

5. A continuous press as in claim 2 in which the machine frame includes a horizontal plate underlying the forward extensions of the side structures.

6. A continuous press as in claim 5 in which one of the forward extensions is releasably secured to said plate and the other forward extension is loosely connected to the plate.

References Cited UNITED STATES PATENTS 1,040,842 10/1912 Anderson 100158 1,092,800 4/1914 R-ach 100-158 2,617,354 11/1952 Ingalls 100-158 X 2,789,618 4/1957 Bennett 100-158 3,105,434 10/1963 Messing 100-158 PETER FELDMAN, Primary Examinez'.

U.S. Cl. X.R. 100--15 8

Images