US3550775A - Method and means for separating entrained liquids from solids - Google Patents

Description

United States Patent Sobotka et al. v.

Shepard Collins Lang et al. La Rosa...

Krause At!rn Berman, Davidson and Berman ABSTRACT: Means for separating entrained liquids from solids, said means comprising: a foraminous cylinder having a closed bottom; a piston reciprocable in said cylinder and means operable between said piston and said closed bottom for cleaning said foraminous cylinder. A method of separating entrained liquids from solids. said method comprising: progressively compressing a mixture of solids and liquids in a chamber having foraminous walls and during such compression repeatedly cleaning said walls.

[72] Inventor William L. Cooley 488,583 12/1892 14215 Squirrel Hollow Lane, Saratoga, 921,01 1 5/ l 909 m. 95070 1,199,350 9/1916 [2]] AppLNo. 717,318 1,990,992 2/1935 [221 Filed Mar. 29,1968 2,427,446 /19 I Patented Dec. 29, 1970 3,269,301 /1 Primary Examiner-John Adee [54] METHOD AND MEANS FOR SEPARATING ENTRAINED LIQUIDS FROM SOLIDS 5 Claims, 8 Drawing Figs.

[52] U.S.Cl 210/81, 2l0/408.2l0/414: lOO/l l2, l00/l27 [51] Int. Cl B0ld 29/00 Field ofSearch 210/79, 81, 407,408.409,4l3,4l4; /112, l27

[56] References Cited UNITED STATES PATENTS 406,]61 7/l889 Chabanel 2l0/4l3X J q 46 4e /2 j; 40 42 0 3M 0 L H l 29% 5: 234 52 I ll 1 v PATENTEU 05029 I970 sum 2 or 3 r IIIIIIIIIIIIIIIIIIIIIII o oo - INVENTOR. WILL/4M COOLES/I PATENTEU UECZ 9 I910 sum 3 or 3 METHOD AND MEANS FOR SEPARATING ENTRAINED LIQUIDS FROM SOLIDS The present invention was developed originally as a wine press" for the purpose of expressing juice from crushed whole grapes. Later, it was found equally applicable to separating oil from copra and removing the liquor from slurries of paper making pulp. Hence, for the purpose of this disclosure, the raw material entering the press will be referred to as a slurry" and the liquid which will ultimately be separated will be referred to as entrained liquid", even though these terms, according to standard dictionary usage, may not be literally applicable to all of the solid-liquid mixtures which may be treated according to this invention.

The fundamental principles and elements of the wine press, namely, a foraminous cylinder with a piston pressing the slurry within the cylinder, are centuries old and, up to a point, are highly effective. The limiting factors, however, are numerous and are difficult of solution. For example, as pressure increases, the wall thickness of the foraminous cylinder also must increase. Another factor is that the larger the apertures of the foraminous member, the more solids will pass through the member along with the liquied. Naturally, an objective of any such pressing operation is to remov'e the highest possible percentage of total liquid entering the press but the almost universal corollary of this objective is to retain in the press and exclude from the liquid the highest possible percentage of the solids entering the press.

In order to maintain a particular maximum permissible stress in the cylinder wall, the thickness must increase directly as the hydrostatic pressure within the cylinder increases. It is also a fact that for a given pressure and thickness the stress increases directly with the diameter so that keeping in mind a limiting maximum stress the thickness must also increase directly as the diameter. When it comes to perforating the cylinder wall for the emission of liquid, small diameter perforations which are most economical in retaining the solids become channels rather than orifices if the thickness is onequarter inch or more and the possibility of clogging therefore increases directly with the thickness and inversely with the diameter of the perforations.

The area of a cylinder increases directly as the diameter while the volume increases as the square of the diameter, which simply means that for a given slurry, if one doubles the available exit area by doubling the diameter one has increased by four times the volume which the double area must carry. It is clearly apparent from such considerations that economics will dictate both the lower and upper limits of diameter in work of this sort. v

It is a primary object of this invention to provide a foraminous cylinder which can be of very substantial thickness for optimum strength but in which the effective area of the perforations can be adjustably varied without impairment of the strength.

It is a further object of this invention to provide in a press of the type discussed means for repeatedly cleaning the interior of the cylinder wall as the charge within the cylinder is reduced in volume, thereby permitting the extraction of a greater percentage of the original liquid content of the slurry.

The above and other objects will be made clear from the following detailed description taken in connection with the annexed drawings, in which:

FIG. I. is a longitudinal cross section of a preferred form of press;

FIG. 2 is an enlarged section of part of the bottom portion of FIG. I;

. FIG. 3. is a cross section showing a modification of FIG. 1; FIG. 4 is a section on the line 4-4 of FIG. 3;

FIG. 5 is a view similar to FIG 1, showing a modified form of cleaning arrangement;

FIG. 6. is a view similar to FIG 5, showing the parts arranged for discharge of the solid residue;

FIG. 7 is a section on the line 7-7 of FIG. 5; and

FIG. 8 is a section on the line 8-8 of FIG. 7.

Referring now to FIG. 1, there is shown a relatively thick outer cylinder 10 having inwardly tapered perforations 12. Inside the sleeve 10 is a supplementary sleeve 14 of substantially less thickness. The sleeve 14 has perforations 16 of a diameter approximating the inner diameter of the tapered perforations 12 and located in precisely the same pattern as the perforaposition shown in FIG 1 or by reversal of the pressure to swing the bottom plate 22 around its pivot in the lugs 20 to open the bottom and permit discharge of residual solids.

A piston 32 snugly fits the interior of the sleeve 14 and is secured to rods 34 attached to pistons 36 within hydraulic cylinders 38. A sleeve 40 is secured to .the piston 32 in a groove 42 formed in the rim of the piston.

The sleeve 10 has an imperforate prolongation 44 in which is formed an opening 46 to which an inlet hopper 48 is attached. An imperforate extension 44 of the inner cylinder 14 underlies the extension 44 and has an opening 46 registering with the opening 46. When the piston 32 is fully withdrawn to the left of FIG 1, the openings 46 and 46' are exposed and the hopper 48 has free access to the interior of the sleeve 14 and a slurry, for example, crushed grapes, may be introduced.

A piston rod 50 penetrates the piston 32 through a packing gland 52 and is connected to a hydraulic piston and cylinder not shown. At its opposite end the rod 50 has a reduced portion 54 which passes through a spheroid cage or spider 56. It then passes through and is secured to an auxiliary piston 58 and thence to a similar spheroid cage orspider 60 to which it also is firmly secured.

The auxiliary piston 58 is of less diameter than the interior of the sleeve 14 and carries a series of helical flutes 62 which snugly fit the interior of the sleeve 14 for wiping contact. There are thus provided helical passageways between the exterior of the piston 58 and the wall 14. The cages 56 and 60 have an exterior diameter corresponding to the base diameter of the cylinder 58 so as not to interfere with the passages defined by the ribs 62.

The operation of the parts just described is as follows: With the perforations 16 of the sleeve 14 in alignment with the perforations 12 of the sleeve 10 (a matter which will be discussed hereinafter) the piston 32 is withdrawn to the left of FIG 1 so as to expose the openings 46 and 46'..At this time, the piston 58 is placed at the extreme right of FIG. 1 with the spheroid 60 in pressure contact with the resilient block 64 secured to the bottom closure plate 22. A charge of slurry, for example, crushed grapes, is then introduced into the sleeve 14 until the space between the two pistons is filled. Pressure is then applied to cylinders 36 and 38 to advance the piston 32 toward the piston 58.

At this stage, the slurry is readily compressible and juice flows freely through the apertures 12 and 16. When the piston 32 arrives at the position shown in FIG 1, it'will be clear that the sleeve 40 has thoroughly closed the opening 46 and shut off the hopper 48. By this time, the easily expressible juice has passed through the sleeve 14 and the cylinder 10 and the perforations l2 and 16 will have tended to clog. At this point, the piston 58 starts to move toward the piston 32. The ribs 6 2 on the piston 58 scrape the inner surfaceof the sleeve 14 as the piston 58 moves toward the piston 32. When the cage 56 contacts the piston 32, a pressure switch, pilot valve limit switch or other suitable means reverses the piston 58. which travels net effect is that as the piston 32 moves fromleft to right,.the

piston 58 is continually reciprocating between the piston 32 r and the box 64, and thereby cleaning the perforation 16 of the sleeve 14. The solids and their residual liquid continually pass through the spaces between the ribs 62 from one side of the piston 58 t the other. This produces a thorough mixing action 'and prevents liquid from becoming entrapped in the region of the rod 50.

if desired, the cages 56 and 60 as well as the piston 58 may be so mounted as to be freely rotatable on the stub 54 of the shaft 50. When thus mounted, the helical character of the rib 62 will produce reverse rotation of the entire structure on and its associated parts. Variations in the shape of piston 58 and its associated parts may be introduced to meet the requirements of various slurrys.

FIG. 2 shows the upper righthand corner of FIG. 1 on an enlarged scale and FIG. 2 makes it very clear that the perforations 16 are straight through or cylindrical and of a diameter approximating the inner diameter of the perforations 12 in the cylinder 10. The cylindrical enlargement 18 of the cylinder 10 has formed adjacent its free end an annular groove 70 which receives a thick annular flange 72 formed on the end of the sleeve 14. One or more cap screws 74 penetrate the flange 72 and screw into the portion 18 of the cylinder 10. One or more shims 76 may be placed between the bottom of the groove 70 and the bottom of the flange 72 which can result in a predetermined offsetting 78 between the perforations 16 and the perforations 12. This provides a means for adjusting the effective area of the perforations .through which the liquid must pass. This is a very considerable advantage from the standpoint of manufacture. When the cylinder 10 is of substantial thickness, which usually will be the case, the drilling of minute holes becomes a considerable problem. The coation of the cylinder 10 and sleeve 14, as illustrated in FIG. 2, provides the means whereby the perforations may be made of an easily formed size but the actual effective area of the perforations is controllable and adjustable.

In FIGS. 3 and 4, so far as the parts are identical with FIG. 1, the same reference numerals are used. This particular form was developed primarily to deal with extracting oil from copra. It will be realized, of course, that grated copra is not a slurry in the usual definition of the term. It is, however a combination of solids liquids which may be separated by compression and, therefore, comes within the term slurry as used herein.

In FIG. 3, a piston 100 is secured to a rod 50. The cylindrical wall 102 ofthe piston 100 is spaced from the interior of the sleeve 14. Formed on the wall 102 are a series of annular lugs 104 which are distinctly circularly arcuate and not helical like the lug 62, discussed in connection with FIG. I. The spheroid shield 106 is mounted on the lead end of the piston 100 and its diameter is identical to that of the cylindrical shell 102.

There are four lugs 104 in each row with a substantial space between adjacent lugs. Consecutive rows are so arranged that the space between the lugs of one row centers on the body ofa lug in each adjacent row, thereby defining between rows a tortuous passageway from one end of the piston 100 to the opposite end.

The rear end of the cylinder 100 is closed by a disc 108 which is threaded to engage, as at 110, similar threads on the interior of the piston 100. The disc 108 is formed with a pair of openings 112 and 114 to which are connected pipes 118 and 120 which, at 122 and 124 are connected to a pair of flexible tubes 126 and 128 mounted in the head 130 in the main frame of the machine. The tubes 126 and 128 act, one as an inlet and the other as an outlet, either for steam to assist in the extraction process if the slurry happens to be copra or as inlet and outlet for a cooling medium if that is indicated by the nature of the slurry to be treated. The sleeve 10 has the usual opening 46 connected to a hopper 48 for charging the device. An arcuate shield 132 is secured to the piston and acts to block the opening 46 as the piston moves into the cylinder. Approximately opposite the opening 46 the imperforate extension of the sleeve has a second opening 134 for a purpose presently to be described. i I.

In compressing copra or .material behaving like copra, as the piston 100 proceeds from left to right, oiliis expressed through the perforations 12 and whenuthe pressure becomes sufficiently high, the residual pulp proceeds through the tortuous channels defined by the lugs 103 104. Additional incoming pulp compresses pulp in the channels 104 with further expression of oil through opening openings 12 which from time to time, during the descent of the piston 100, are cleaned by the passage thereover of the lugs 104. Finally,-the pulp which by now has had most of the coil removed arrives at the final row of lugs 104.

A ring 136 is secured to-the disc 110 by cap screws 138 1 which pass through arcuate slots 140 in-the ring 134. These are best seen-in FIG. 4.

The outer periphery of the ring 136 has notches 142 which are spaced corresponding to the spaces between lugs 104 in the last row of lugs. The arcuateslots-140 permit adjustment of the ring 136 so that the degree of overlap between the slots 142 and the spaces between the lugs 104 is adjustable and thus the maximum pressure to which the material between the lugs 104 is subjected can be regulated. After the piston arrives at the end of its stoke against the block 64, virtually all of the original charge either will have passed through the piston or will be entrapped between the several lugs 104. When the piston is withdrawn leftward in FIG, 3, the pulp which has passed through the piston and accumulated on its top can be removed through the opening 134. The piston is then raised further so that the shield 132 clears the opening 46 and a fresh charge is injected. The pulp remaining between the lugs 104 at the end of a cycle will be the first to pass through between the lugs 104 and accumulate on top of the piston at the next cycle of operations. As in the case of FIG. 1, one of the principal ef fects of this arrangement is thorough mixing and remixing of the pulp with consequent avoidance of any localized and centralized pockets ofoil orjuice.

FIGS. 5 through 8 show a very useful a variation on the form of FIG. 1. Here a sleeve or cylinder 200 has perforations 202 throughout its active wall. A piston 204 is connected to a pair of piston rods 206, each of which is connected to a piston inside a cylinder 208. A ring spider device 210 is connected to a rod 212 which is connected at its opposite end to a piston within a cylinder 214. The action of the piston 204 and device 210 is identical with that described in connection with FIG. 1.

As seen in FIGS. 7 and 8, however, the ring and spider device 210 is made up ofidentical halves 216 and 218, each of which has an annular groove 220 and 222. These grooves meet to provide in the device 210 a complete peripheral groove 223. The device actually comprises an exterior ring 226 connected by spokes 228 which permit free passage of the pulp through the piston 210 as it reciprocates between the piston 204 and the bottom closure 230. At the center the spokes 228 connect to a hub 232 which is hollow, as indicated at 234, around a central post 236. The post 236 is actually a reduced diameter extension of the rod 212. The free end of the post 236 is solid and threaded to engage a nut 238 which binds together the halves 216 and 218. Each of the spokes 228.

has a central channel 240 communicating with the base of the groove 224. The groove 224 defines with the cylinder 200 a channel extending around the entire periphery of the device 210 and the base of the groove 224 has a series of radially and inwardly directed grooves 244.

A piston rod 212 is hollow, as indicated at 246 in FIG. 7, and fluid is continually supplied therethrough. This fluid is distributed through the spokes 228, the hub 232, which also contains radial grooves 248, and outwardly via channel 224 through the perforations 202 and inwardly through the perforations 244. The purpose of the device, as shown in FIGS. 5- 8, is as follows: v

For many purposes the liquid extracted by a pressing operation is unimportant as such.-lts importance 'lies in the chemicals dissolved in the liquid. A typical instance of this is the washing of freshly digested wood pulp where the liquor contains sodium carbonate, soda ash, sodium sulfate and dissolved ligneous material. The soda compounds are all recoverable. If the press in such case were operative merely to extract black liquor from the pulp, whatever residual liquid remained in the pulp would be highly concentrated which would mean a loss of a substantial portion of the otherwise recoverable chemicals. Accordingly, wash water, either pure water or, preferably, weak black liquor, is supplied at all times through the channel 246. This liquor not only operates via the channel 224 to effect an even morethorough cleaning of the holes 202 but as the device 210 reciprocates, wash liquor isat all times through distributed through the pulp, resulting in a gradual dilution of the liquor in the pulp and resulting in the recovery of a greater proportion of the chemicals in the liquor even though at somewhat more dilute condition than would be the case if the wash liquor were omitted.

For an example of the same action, assume that copra is the material being treated: the fatty acids which constitute the coconut oil are soluble in ether which may be used as a wash liquor, assuring a greater removal of total fatty acids and less residual fatty acid in the finally discarded'pulp. Numerous other uses doubtless will co occur to those skilled in the art.

Good practice in the use of the equipment of FIGS. 5-8 is illustrated in FIG. 6, where the gate 230 is opened and the piston 210 is permitted to pass far enough through the sleeve 200 to expose the groove 224 and permit free flow of wash fluid to all of the parts. This thoroughly cleans the piston 210 and readies it for the next cycle.

It will be noted that all of the forms heretofore discussed perform essentially the same process, namely, compressing a slurry within a foraminous shell and during such compression continually cleaning the shell to permit expression of the liquid vehicle while continuing to compress the residual solids.

No doubt, the foregoing disclosure will suggest to those skilled in the art numerous modifications. It is not intended, therefore, to' limit this invention to the precise details disclosed but only as set forth in the subjoined claims.

I claim: I t

1. Means for separating entrained liquids from solids, said means comprising: a foraminous cylinder having a releasable closure at one end; a piston reciprocable in said cylinder for expressing liquid from a slurry, a slurry inlet adjacent the opposite end of said cylinder, the stroke of said piston being such as to expose said inlet when said piston is in its most withdrawn position; means on said piston for closing said inlet when said piston moves inwardly of said cylinder from said most withdrawn position and a second piston reciprocable between said first piston and said releasable closure, said reciprocation taking place during the approach of said first piston toward said closure, said second piston having means to permit passage of slurry from one side to the other during it its reciprocation, and also having means axially to scrape the entire circumference of said cylinder.

2. Means as set forth in claim 1 for supplying wash fluid to and through said second piston.-

3. Means as set forth in claim 1 in which said cylinder comprise a relatively thick pressure resistant outer shell having perforations through its active surface; a relatively thin inner shell having a pattern of perforations corresponding to said outer shell and means for relative axial adjustment between said shells to adjust the net area of partially'registering perforations of the two shells.

4. A method of separating entrained liquids from solids, said method comprising: axially compressing a slurry of solids and liquids in a chamber having a foraminous cylindrical wall, said wall having a transyerse closure at one end, said compression expressing the liquid portion of said slurry through said wall,

thus reducing the volume of said chamber occupied by said slurry and during said compression, repeatedly axially scraping in advance of said compression and throughout its circumference, that portion of said wall in contact with said slurry.

5. The method of claim 4, in which the scraping is by wash ing action.

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