US2917992A

US2917992A - Multi-chamber press

Info

Publication number: US2917992A
Application number: US517590A
Authority: US
Inventors: William S Carver; Philip H Condit; Joseph A Schaines
Original assignee: FRED S CARVER Inc
Current assignee: FRED S CARVER Inc
Priority date: 1949-10-08
Filing date: 1955-06-14
Publication date: 1959-12-22
Anticipated expiration: 1976-12-22

Description

Dec. 22, 1959 F. s. cARvER MULTI-CHAMBER PRESS 1 m n t w m m m h a 0 MN I W m V p A MW. m E H 0 mm 6 l Pains flu ukumtvi firs? Q%%.%%

Bast 3 Original Filed Oct. 8, 1949 Dec. 22, 1959 F. s. CARVER MULTI-Cl-IAMBER PRESS Original Filed Oct. 8,

6 Sheets-*Sheet 2 INVENTOR.

FRED ,5. CAR VER HTTVKNEY Dec. 22, 1959 F, s, CARVER 2,917,992

MULTI-CHAMBER PRESS 7 Original Filed Oct. 8, 1949 6 Sheets-Sheet 5 nvvrox a FRED 5. CAR v21? 5 ir 4 I 0 I I '"I 4 l-I M F ATTORNEY Dec. 22, 1959 F. s. CARVER 2,917,992

MULTI-CHAMBER PRESS Original Filed Oct. 8, 1949 6 Sheets-Sheet 4 $5 INVENTOR. FRED SI CARVE A T TOIFNE Y Dec. 22, 1959 I F. S. CARVER MULTI- CHAMBER PRESS Original Filed Oct. 8, 1949 6 Sheets-Sheet 5 25v 20v Z TJEFE.

THEE E.

M 2W l I INVENTOR: 3 a; FRED ,5. 63mm? ATTORNEY Dec. 22, 1959 F. s. CARVER 2,917,992

MULTI-CHAMBER PRESS Original Filed Oct. 8, 1949 6 Sheets-Sheet 6 INVENTOR. FRED S. CARVER 19 TTORNEY United States Patent MULTI-CHAMBER PRESS Fred S. Carver, Short Hills, N.J.; William S.'Carver, Philip H. Condit, and Joseph A. Sehaines, executors of said Fred S. Carver, deceased; said Fred S. Carver assignor to Fred S. Carver, Inc., Summit, N.J., a corporation of New York Original application October 8, 1949, Serial No. 120,381,

now Patent No. 2,714,849, dated August 9, 1955. Divided and this application June 14, 1955, Serial No. 517,590

1 Claim. (Cl. 100-37) The present invention relates to processes for separating liquid constituents, such as oil or water, from the solid constituents of materials of various kinds, such as cocoa, copra, and other vegetable oil bearing materials, 'which are in, or have preliminarily been reduced to, substantially semi-liquid state slurries, mother liquors from crystallization, etc., all of which are adapted to be moved and put under pressure by a pumping operation.

This application constitutes a division of my prior application which issued as Pat. No. 2,714,849.

With the press of the present invention, feeding is performed by pumping in the material in a more or less [fluid state under pressure, the pumping pressure being relatively high, as 800 pounds per square inch, for example, and continued for some time after the press has been filled in order to cause an initial filtering; the press chambers are then shortened by application of external pressure, whereby a further expressing of liquid is performed, together with caking of residual solids; and further steps of operation include collecting the expressed liquid; elongating the press chambers to their original length; opening up the press chambers in such a way that in a horizontally arranged press the press cakes fall out from the opened chambers; reclosing the press chamber sides whereupon the press is ready for refeeding; and repeating these steps through repeated cycles of operation.

It is an object of this invention to provide an apparatus adapted to separate fluids from solids simply, efliciently, rapidly, and substantially continuously, the operation whereof can beas nearly fully automatic as in practice is feasible.

The present invention is more particularly directed toward improvements in presses of the type shown in my United States Patents 2,247,988 of July 1, 1941, 2,072,942 of March 9, 1937, and 1,771,526 of July 29, 1930.

The present invention contemplates improvements in multi-chamber presses preferably of the horizontal type, wherein a movable ring is horizontally shifted relative to an associated pair of filtering elements for each chamber to either form a closed chamber or to open the chamber for discharge of the pressed cake formed in it, these improvements relating to the devices employed in spacing and retracting the chamber-forming rings at the close of the pressing operation, and having means which not only tie the platen for one unit of the press to the platen for adjacent units, whereby the expansion of each chamher is limited and controlled, but also during the compression stroke of the press permits over-travel of all parts toward the resistance head. In accomplishing this, it is contemplated that all the platens, filter parts, chamber-forming rings, pistons, platen tie connections, and springs of the units may be identical and interchangeable (except for minor differences at the ends of the press) so as to reduce the cost of manufacture, maintenance and servicing; also the. ring retracting means is in the form tion rather than limiting the same.

ice

of suitable similarly reciprocable power retractible shafts provided with abutments, certain of which are engageable by the rings during the compression stroke, and all of which are engageable with the rings when the shafts are retracted to open the press chambers. These parts are provided with suitable over-travel or lost motion so as to avoid interference of one part with the other when ram pressure is applied. When the travel ofthe ram exceeds the maximum length of an open chamberforming unit with its associated parts, provision is made for additional over-travel or lost motion, whereby it is possible to provide a multi-chamber press in which the press unit nearest the ram travels during the compression stroke into a region partly occupied by the adjacent press unit when the press was open.

A further object of the present invention is to provide a multi-chamber press of the type having filter plates, screens and telescoping rings characterized by the absense of lateral projections so that the resulting cake produced by extracting the liquid materials is a flat disc, smooth on both faces. The elimination of projecting parts from the interior of the chamber, which tend to narrow the chamber in any way, makes it possible to secure greater cake thickness throughout, makes it impossible to over-load the press so that it cannot be opened far enough to clear cakes from obstructions which had caused undercuts and facilitates the release of the compressed cake from the screen without having to clear any projecting surface.

In carrying out the present invention, the press has stationary heads connected together by tie members which maintain fixed spacing, one being a ram-carrying head, a plurality of platens carrying filtering elements; a plurality of pistons carrying filtering elements and alternating with the platens, each of the pistons being secured to an adjacent platen to form a pair of carriers which move as a unit, the other filtering element carriers being secured respectively to the ram and the remote head to form a series of filter chambers with influent passages and effluent passages, a series of tie connections which secure the ram, the remote head and each of the pairs of carriers together, these including elements having lost motion therebetween which limit the separation of the carriers of adjacent pairs but allow adjacent pairs to approach one another when the ram acts to move the filtering elements toward one another, a plurality of peripheral rings one for each chamber, spring means interposed, between each ring and one of the carriers of a chamber. to force the ring past the filtering elements and against the adjacent corresponding carrier to close the chamber, the spring means being compressible when the ram closes the press to form a cake, the expansion of the spring means on release of the ram pressure being effective to separate one of the filtering elements from the cake, this expansion being limited by the lost motion tie connections, and means acting on each of the rings to shift the. ring to the chamber opening position and pull the cake away from the other filtering element against the resistance of the tie connections so as to free the cake so that in a horizontal press it may fall of its own weight.

Other and further objects of the invention will appear as the description proceeds.

The accompanying drawings show, for purposes of illustrating the present invention, three of the many embodiments in which the invention may take form, it being I understood that the drawings are illustrative of the inVen-J In the drawings: Figure l is a top plan view of a horizontal press with parts broken away and showing the relation of the parts after the chambers have been filled by the extraneous pump with the solids compacted and before ram pressure 3 v is applied, the ring-retracting mechanism being shown along the line 11 of Fig. 4, other parts being broken away to show interior construction;

Figure 2 is a view similar to Figure 1 showing the position of the parts at the end of the compression stroke ofthe ram;

Figure 3 is a view similar to Figure 1, showing the position of the parts at the completion of the back or returnstroke of the'ring-return mechanism, the pressed cakes'rernote from the ram being shown in position prior to dropping free of the filter plates;

Figure 4 is a front elevational view of the press with the chambers closed and prior to application of ram pressure;

Figure 5 is a transverse sectional view on the line 5+5'of Fig. l;

Figure 6 is 'an enlarged sectional view on the line 6 6 of Figure 5, illustrating the inter-relation of two adjacent platens and interposed filter plates, chamberclosing'rings, ring-operating springs, and lost-motion tie connections between platens, the parts being shown in the position assumed when the chamber is closed by the ring-and when ram pressure is not applied;

Figures 7 and 7a are views similar to Fig. 6, respectively showing the position the parts assume when ram pressure has been applied to shorten the filter chamber, and when ram pressure is released and the initial break has been made between the filtering screen and cake;

Figure 8 is a view on a larger scale, showing in full lines the inter-relations of the pull-back mechanism and the chamber-closing rings when in the position of Fig. l; Figures 9a to 9g, inclusive, are elevational views taken from the right of Figs. 1 to 4, inclusive, showing the principal elements used in the press, Fig. 9a showing the platen, Fig. 9b showing one of the filter screen supporting plates, Fig. 90 showing the filter screen, Fig. 9d showing the filter screen-retaining ring, Fig. 9e showing the peripheral chamber-closing ring, Fig. 9f showing the 'piston, and Fig. 9g showing the cross-head;

Figure 10 is a still further enlarged view showing an assembly of a platen with associated filter plate, filter screen, and screen-securing ring, and showing influent and eflluent passages;

Figure 11 is a cross-sectional view taken on the broken line 11-11 of Fig. 10, illustrating a complete press chamber unit with the closed chamber filled with material to be pressed;

Figure 11a is a fragmentary view illustrating the formation of a plug in the orifice when pressure is applied;

Figures 12 and 12a are enlarged sectional views on the broken line 12-12 of Figures 5 and 10, illustrating the effluent passages;

Figure 13 is a rear elevational view illustrating the feed piping arrangement leading to the chamber units;

Figure 14 is a fragmentary view of horizontal press in which certain of the parts are reversely arranged; and

Figure 15 is an elevational view illustrating a vertical press.

I The horizontal press of Figures 1 to 13 has two stationary supports, namely, a resistance head and a ram head 21, these heads being interconnected by four square tie members or strain rods 22 threaded on the ends and carrying nuts 23, as indicated more clearly in Figure 1. The ram head 21 has a cylindrical chamber 24, carries a gland ring 25, and receives a ram 26. It is connected at 27 to hydraulic mechanism (not shown) whereby oil may be pumped into the ram head under high pressure (say 6000 lbs. per square inch). The cylindrical portion of the ram 26 which travels in the ram cylinder 24 is secured to the ram cross-head 28 (Fig. 9g) by bolts 28a entering holes 2812.

Between the cross-head 28 and the resistance head 20, the press shown in the drawings has twelve chambers, forming units, which, except for terminal connections are duplicates of one another.

On the side of the cross-head 26 opposite the ram it is secured to the first of thirteen steam platens 29, all alike and marked 29a-29m, inclusive, Fig. 1 only (except as noted), by screws 30 passing through holes 31 in the cross-head and entering tapped openings 32 in the platen. The cross-head has a centering boss 28' to enter a central hole 29 in the platen and assist in aligning the parts.

The'right platen 29a, before being secured to the crosshead is secured to one of twelve pistons 33 (marked 33a- 33!, inclusive, Fig. 2) by screws indicated at 34 passing through counterbored holes 35 in the platen and threaded into tapped openings 36 in the rear face of the piston (see Fig. 11). The pistons have centering bosses 33 to enter the holes 29 in the platens.

The front or left faces of the pistons 33 carry filtering elements, designated generally as 38. These are secured by screws 39 passingthrough holes 40 in plates 41 and threaded into the pistons at 42, the parts being centered by boss and recess as indicated at 41', Fig. 11.

The other platens 29b-29m, inclusive, carry, on the right face (toward the ram) identical filtering elements secured to them by similar screws 39 threaded into holes 32. The last platen 29m is secured to the resistancehead by another set of screws 34, indicated at the upper left of Fig. 1. It will thus be seen that, except at the ends, the intermediate platens 29b29l, inclusive, carry on one side a piston 33 and filtering element 38 and on the other side a filtering element 38. Each of the platens has a steam passage indicated in dotted lines 43, Fig. 9a. so that the chambers may be heated from both sides. I

Peripheral ring members 45 (shown in outline in Fig. 9e and also called chamber rings) are received between adjacent platens 29 and are adapted to fit about the filtering elements 38, when in the chamber closing position of Figs. 1, 2 and 11, or to be retracted about the pistons 33 as shown in Fig. 3 and in dotted lines in Fig, 11. Twelve of these rings are used here and are marked 45a- 45], inclusive.

The cross-head 28, platens 29 and rings 45 have hearing surfaces (indicated at 46, 47 and 48, Figs. 9g, 9e, 96, respectively), which surfaces rest on guides 50 and 51 carried by the lower tie or strain members 22 (see Fig. 5). The platens 29 have four holes 52 at tne corners, each hole being surrounded by an annular recess 53 (see Figs. 6 and 7). The peripheral rings 45 have lugs'54 internally counterbored at 55 (see Figs. 6 and 7), spaced the same as the holes 52 in the platen. The cross-head, Fig. 9g, has four similarly aligned holes 56 of smaller diameter.

The resistance head 20 carries four shouldered bushings 57 threaded into it and having heads 58 which extend through the holes 52 in the adjacent platen 29m. Each of the other platens 29, as shown more clearly in Figs. 6 and 7 carries sleeves 59 on the same spacing as the holes 52. The sleeves have reduced ends 60 tofit the holes 52 and reducing shoulders 61 at the other end to provide elongated recesses 61'. The sleeves 59 are secured to the platens (except the one fastened to the resistance head) by bushings 62 internally threaded as indicated at 63. The sleeves 59 receive bolts 64 having heads 65 in the recesses 61' and threaded as indicated at 63'. The bolts 64 are threaded into the bushings 62 and at the resistance head end of the press another set of these bolts is threaded into the bushings 57. The cross-head 28 is, as shown in Fig. 1, connected to the bushings 62 on the adjacent platen by similar bolts 64a in holes 56 so that four aligned lost-motion-tie-connections interconnect the ram with the resistance head and each platen.

Coiled springs 66 are received in the recesses 53 in the platens and bear against the flanges at the bottom of the counterbored holes 55' of the peripheral rings. When the press is assembled, these springs are placed under initial compression by blocking the rings behind horseshoe-shaped clips (not shown) adapted to fitin'to the undercuts 64' on the bolts 64. Each set of springs fora peripheral ring acts to push the peripheral ring toward the platen to its left, so as to place the ring in Chamber-closing position as shown in Figs. 1, 4, 6, 7 and 11. The reaction of the springs in the left chamber is toward the platen to its right. This carries the corresponding piston with it to spread the filtering elements apart. The cumulative action of the springs insures that all the peripheral rings are in the chamber-closing position, the chambers spread, and that the ram is pushed toward the ram head. The extent of this expanding operation is controlled by the take-up of the lost-motion connections including the sleeves 59 and bolts 64. The ram is stopped by the engagement with the end wall of the ram head.

The ring retracting mechanism is carried at the front and rear of the machine and at the level of the center line of the press. The rings 45 are provided with forked lugs 67 opposite one another, as more clearly shown in Fig. 9c. The ram head carries

hydraulic cylinders

68, 68. The resistance head 20 carries guide

cylinders

69, 69 at the same level. The cylinders 68 carry pistons 70, hydraulically operated when ram pressure is released, and connected to piston rods 71 extending through guide bushings 72 carried in openings 73 in the cross-head 28. The rods 71 are drilled and tapped as indicated at 74 (Fig. 8) to receive the reduced threaded ends of shafts 75. The shafts 75 are long enough to reach over to the resistance head and enter the guide cylinders 69. Near the ram head end, the shafts 75 carry collars 76. Each shaft receives three

sleeves

77, 78 and 79. These sleeves are alike. The sleeve 77 atthe right is secured by screws 80 to a split ring 81 received in a reduced diameter portion 82 of the shaft. The sleeve 78 is secured by screws 83 to a similar split ring 84 received in an elongated reduced diameter portion 85 of the shaft 75. The sleeve 79 is held on the shaft by collar 86 and nut 87. The sleeve 77 carries three collars 88a, 88b and 880; the split ring 81 carries a collar 88d. The sleeve 78 and split ring 84 similarly carry collars 88c, 88 88g and 88h. The sleeve 79 similarly carries collars 881', 88j, 88k, and the collar 86 provides an abutment or stop 88L These collars 88a-88l are each to the left of the corresponding rings 45a-45l, respectively.

When the springs 66 have moved the peripheral rings to chamber-closing position (as shown in Figs. 1 and 8), the lugs 67a to 671 engage with the corresponding collars 88a to 88!, inclusive, carried by the shafts 75, and the parts carried by the shafts 75 are connected so that any leftward movement of the ram will cause the shafts 75 to move to the left pulling the piston rods 71 and pistons 70 to the left.

Inasmuch as all the units shorten simultaneously under ram pressure, there is greater travel of the ram and units at the right than of the units at the left. The parts shift after the fashion of an accordion or camera bellows. The present press is designed to permit the amount of this travel for the extreme right unit to exceed the overall spacing between two adjacent units. This requires that all parts of the second unit and succeeding units be moved beyond the region into which parts of the first unit and succeeding units may move. As soon as the press starts to close, the lugs 67a engage the collars 88a, and this causes a corresponding shifting of the shafts 75 and the

collars

88b, 88c and 88d. Due to the lost-motion connection provided by the long reduced portion 85 of the shaft, the rate of movement of the sleeve 78 will be controlled by the engagement of lugs 67c and collars 88c. Similarly, the movement of the left lugs 671 and collars 88i. When the press is completely closed by the ram, the parts assume the position shown in Fig. 2, and the shafts 75 and all movable parts associated with them are to the left of the position shown sleeve 79 will be controlled by the engagement of the 6. in Figs. 1 and 8, lug 67a havingmoved to some such position as indicated in dotted lines in Fig. 8.

As soon as ram pressure is relieved, the springs 66 act to expand the assemblage, moving the parts from the position in Fig. 2 to substantially the position of Fig. 1. This movement has caused each piston and filtering element to shift from the closed position shown in Fig. 7, where it is against cake C, to the position shown in Fig. 7a, where it has pulled the -right-hand (or piston carried) filtering element 38 away from cake C.

When high pressure liquid is admitted through ports 68a to the left ends of cylinders 68, the pistons 70 will be shifted from the position of Fig. 2 to the position of Fig. 3. This shifting has, at least in part, been accomplished by the expansion of the springs 66 and is positively completed by the pistons 70. When the shafts move to the right, they first bring the collars 76 against the cross-head 28 so as to apply ample power to return the ram. The ram is accurately aligned in the cylinder and this insures lining up of all the parts. At the same time, the

collars

88a, 88b, 88c and 88d move as a unit and successively pick up the lugs 67a, 67b, 67c, 67d on four rings -45a-45d inclusive toward the ram end of the machine. When sufiicient lost motion is taken up by this movement, the collars 88c, 881', 88g, 88h pick up the nextfour rings and move them to the right; and in the same manner the collars 88i, 88f, 88k and 88l pick up or bring the other four peripheral rings to the extreme right position as shown in Fig. 3. In this power stroke 1 of the pistons 70, the rings 45 are all moved to the extreme right position, so that the rings are beyond the filtering elements. The power stroke of the shafts'75 successively takes up the lost motion, shifts the rings 45 against spring pressure, separates the cakes C from the left filteringelements 38, and brings the free surfaces of the cakes against the right filtering elements 38 which arrest movement of the cakes. Continued movement of the rings causes them to slide past the cakes so that at the full return stroke of the rings the cakes are all free to fall out of the press.

' Figure 5 and Figures 9a to 13, inclusive, illustrate the component parts of the press unit in greater detail. Each platen 29 is tapped at the inlet 89 and has an obliquely sloping drilling 90 leading to the center opening 29' having a keyway slot cut at 91 opposite the passage 90. The openings 29 receive plugs 92 with keys 93 and angled passages 94 connecting to passage 90.

The rear face of each pressure plate 41 has annular grooves 99, Figs. 10 and 11, forming passages and radial grooves communicating with drillings 101, which in turncommunicate with annular grooves 102 on the front face. The outer annular groove 99 on the back face 'of the pressure plate drains into drillings 103 and 104 in the platen and piston, respectively, as shown more clearly in Fig. 12.

The front face of the plate has inner and outer annular, fiat,

coplanar surfaces

105, 106. Outside the flat surface 105 is a beveled surface 107, and on the inside of surface 106 is another beveled surface 108. A spacer 109 in the form of a relatively coarse, rolled, cross-wire-mesh screen, calendered to flatness, is received in the recess 110 in the front face extending between the fiat surfaces 105, 106. A filtering screen 111 (Fig. 90) made of fine wire and a backing plate 112 of perforated sheet metal, are flanged at the periphery and near the center, as indicated at 113 and 114 (Figs. 12 and 12a) so as to fit about the beveled surfaces 107 and 108. A filter screen securing ring 115 (Fig. 9d) is held against the periphery of the filtering screen by screws 116.

The inner fianges of the filter screens secured to plates 41 (carried by platens 29b-29m, inclusive) are secured in place by inlet nozzles 117 having conical heads 118 and threaded into central holes 119 in the plates 41, thereby connecting inlet passage 90 to the chamber. The nozzle is reamed at 117a to have a slight taper and is closing the chambers.

provided with a taper of about 45 at 117b. The screens on the filtering elements carried by pistons are secured in place by plugs 120. Instead of supplying material to be filtered to the chambers by inlets communicating directly to the platen, it is obvious that the feed could be from a platen through a piston and nozzle, as indicated in Figure 14.

It will be noted that the filtering elements 38 are characterized by the absence of any projections which obstruct or hinder the lateral movement of the cake. When the initial break is made between the filtering element and the right-hand side of the cake C, the cake C has a smooth vertical surface free of undercuts, and when the cake C is broken away from the left filtering element, it has a similar smooth face except for the plug of material hereafter referred to. These faces are vertical in the horizontal press of Figures 1 'to 13. As soon as the rings 45 are withdrawn far enough to release the cakes, the cakes fall out of the machine onto a cake conveyor, chute or the like, without any hindrance or need for longitudinal movement whatever.

This contour of cake face makes it impossible to overload the machine in such a way that the cake might be formed too thick to clear horizontal projections. The overall capacity of the machine is thus greatly increased over that of the former machine of the same size, wherein the cakes produced necessarily had undercuts which interfered with the cake falling freely out of the open press chambers if filled beyond a certain capacity.

The liquid expressed through the filtering elements 38 enters holes 103 in the platens and 104 in the pistons, which are aligned (Fig. 12), and the liquid received in these passages drains down through a passage 121 leading to the bottom of the platen. The 'efiiuent passages 121 are connected by elbows 122 to drain pipe 123, which carry expressed liquor across to a trough 124 extending longitudinally of the machine.

Influent material to be filtered is received from pumps extraneous of the machine through a low pressure line indicated in Figs. 4 and 13 at 130, or through ahigh pressure line indicated at 131. It passes downwardly through suitable piping indicated at 132, to a T 133, where it is connected to a liquor supply pipe 134 extending from the resistance head to the ram head of the machine, and provided with a drain valve at 135. As seen more clearly in Figs. 1, and 13, the liquor supply pipe 134 is connected through stationary piping 136 to platen 29m and to a series-of eleven walking pipes 137 connected to platens 2913-291, inclusive, said' piping including valves 139 so that it is possible went off supply to all but one platen and apply pressure to dislodge clogging inaterial. Platen 29a is plu ged at its inlet 89.

Steam enters a manifold 140 onthe-upper front part of the machine, Fig. 4, and passes through a stationary pipe 141 connected to platen 29m and twelve walking pipes 142 connected to platens 29a to 291, inclusive, so as to supply the platen steam passages 43. Steam and condensate pass from the lower ends of'passages-43 into pipes 143 similarly connected to outlet manifold 144.

While the outer ends of cylinders 68 are normally vented as indicated at 6812 (Figs. 1,2 and 3), they may be connected (especially in larger presses) to a continuous source of air under pressure as indicated at68b' (Fig. '4). Compressed air in these cylinders will assist in expelling the hydraulic fluid through ports 68a'and in shifting the shafts 75 and parts carried thereby back to the position of Fig. 1, thereby relieving springs 66 of this load.

Operation The press parts are normally in the position shown in Figures 1, 4, 5, 6 and-11, the filter elements38, 38 being spaced the maximum and the peripheral rings 45 Liquid to be filtered is .supplied to the platens, except 2%, and throughthe passages in these platens and orifices 117 entersthe chambers at the'c'enter. While liquidmaybe pumped into smaller presses at moderately high pump pressures of 500 lbs. per square inch, it is preferable with larger presses and where higher pump pressures of 800 lbs. per square inch are attained, to preliminarily fill the press at a pressure of about 300 lbs. per square inch, as through a low pressure line 130, before applying the higher pressure through line 131. The forces are better balanced by first employing the lower pressure.

The pumping operation fills all chambers with the filterable material and a substantial portion of the liquid content is forced through the screens so as to create deposits in the form of semi-solid cakes which completely fill the chambers. The supply pumps for the material to be filtered are then shut down. High pressure fluid is admitted to the cylinder in the ram head. This fluid pressure, which may be of the order of 6000 pounds per square inch, presses the cross-head and all the pistons, rings, platens and interconnected parts toward the stationary elements carried by the head. This shortens the chambers, as indicated by comparing the positions of the parts in Figures 1 and 2, and presses the available residual liquid from the cakes through the screens and drainage passages. It also tends to push some of the solids back into the nozzle 117, which forms a lug of caked material to plug the nozzle. This action is indicated in Figure 11a by the density of the stippling. Some of the highly compacted material in the chamber will tend to escape by flowing backwardly in the nozzle, but it meets the smoothly polished sloping surfaces 117b of the nozzle and compacts in a manner to effectively pinch otf further flow. The plug acts as a check valve. This plug is only about in diameter at its inner end and is readily sheared off when the press is open and the cake drops.

After ram pressure has been applied in sufficient extent and time to press sufficient residual liquid from the cakes, ram pressure is released, whereupon the expansion springs 66 force all the parts between the fixed platen and filtering element and the ram toward the right, forcing the ram back into the ram head and separating the right filtering screens from the cakes. Concurrently with the release of the pressure in the ram cylinder, fluid pressure is applied to the left faces of the pistons 70 in cylinders 68. The first movement of these pistons brings the collars 76 against the cross-head and as the ram has large bearing areas in the cylinder wall of the ram head, these parts are shifted back accurately in line. This insures that the rods 75 with collars attached will operate in unison and engage the lugs on each peripheral ring and pull the rings back, this action taking place successively from rings 45a to 451. The shiftingof the rings 45 to the right will break the left faces of the cakesaway from the left filtering elements and as each ring passes clear of the corresponding right filtering element (Figs. 3 and 11), the cakes fall clear of the machine onto a .conveyor or chute so that the cakes may drop without any resistance being oifered by undercuts and projections which would occur in the press without fiat, parallel filtering elements. By avoiding interference with cake removal due to obstructions arising from cake contour, it is possible to fill the chambers to maximum capacity and after pressing, remove the cakes. It -is impossible to overfill the chambers.

As soon as the cakes are'freed fro-mthe chambers, pressure is released in hydraulic cylinders 68 and the springs 66 return the rings 45 to the position of Fig. l and carry the pistons '70 and rods 75 carried thereby from the extreme right position of Fig. 3 to the intermediate position of Fig. 1. Parts have therebybeen restored to the position first discussed and the press is ready for another cycle of operations."

Figure 14.shows a horizontal press generally similar to the horizontal press :above .described in detail, but having a reversed arrangement of 'certain of the parts and operations. The resistance and ram heads areindicat e d at 151 and 152. The ram head carries a ram 153 connected to a ram cross-head 154 as previously described and this cross-head is interconnected with the resistance head through lost motion tie connections 155 generally the same as those previously described. Here similar platens 156 may be employed but instead of having the faces of the platens toward the ram directly carry filtering elements, as previously described, these faces of the platens carry pistons 157. The pistons and other faces of all the platens carry filtering elements 38 as above described. The pistons 157 are like the pistons previously described, except that they have a central opening 158 to carry the infiuent from the platens to the nozzle. The expressed liquor drains through the platens and pistons are previously described. Each unit is provided with a chamber forming or peripheral ring 160 similar to the ring 45 but urged toward the ram by springs 161. The pistons are steam heated as before and the pressing operation is carried out in the same way by applying pressure to the ram 153. On release of the ram pressure, the springs will expand, forcing the ram back into the ram head. In the construction of Figure 14, however, the cross-head 154 carries cylinders 162 which extend back alongside the ram head. These cylinders are connected to suitable hydraulic mechanism through ports 163 to the right of the pistons 164. The pistons 1'64 operate shafts 165 similar to the shafts 75 but move them toward the resistance head instead of being pulled towardthe ram head as above described. Similar lost motion connections between the shafts 165, and various collars (like 88a-88I) adapted to cooperate with the rings would be'ernployed. With this arrangement reaction to the pressure applied in the cylinders 162 forces the ram into the ram head and insures the spacing of the filter chamber walls while the peripheral rings are being pressed back over the pistons to open the chambers and allow removal of the cake.

The form shown in Figure 15 is a vertical press which may be substantially identical with the horizontal presses above described. The parts are in general the same, and in Figure 15 corresponding reference characters with the letter V added are applied. Instead of having the entire press supported by feet carried by the ram head and resistance head as shown in Figure 4, here the ram head of the press is carried on legs 170. Instead of having the platens, peripheral rings and cross-heads supported by gravity on horizontal tie members, here the tie members 171 act as guides for these parts. Gravity aids in opening the press and suitable mechanism, not shown, would be provided to laterally remove the cakes from the smooth filter screens provided by the construction shown in detail in the earlier figures.

Since it is obvious that the invention may be embodied In other forms and constructions within the scope of the claim, I wish it to be understood that the particular forms shown are but three of these forms, and various modifications and changes being possible, I do hot otherwise limit myself in any way with respect thereto.

What is claimed is:

The method which comprises pumping under substantial pressure a liquor having filterable liquid and unfilterable solids through an inlet opening and into a closed chamber having filtrate outlets to preliminarily consolidate the solids and expel a substantial portion of the liquid, discontinuing pumping, applying extraneous pressure to the chamber in greater amount per unit area than the pumping pressure to further consolidate the solids and expel residual liquid, and concurrently intercepting a portion of said more consolidated material about the inlet and forcing it sharply toward the axis of the inlet opening and then gradually toward said axis to restrict axial movement of said portion.

References Cited in the file of this patent UNITED STATES PATENTS 1,331,453 Bausman Feb. 17, 1920 2,072,942 Carver Mar. 9, 1937 2,178,416 Bausman Oct. 31, 1939 2,247,988 Carver July 1, 1941