US2427662A - Self-cleaning fluid extractor for high consistency mixtures - Google Patents

Description

Sept 23, `1947. 1 -J. DE LA RozA, SR A 2,427,662

SELF-CLEANING FLUID EXTRACTOR FOR HIGH CONSISTENCY MIXTURES Filed'June 24, 1944 4 Sheets-Sheet l lllll Il llulm 4 muvA Mall!! L? 1' if /l7a J` l l i 7 s* ily "1 mlm..

MIXTURES 4 Sheets-Sheet 2 INVENTOR. gaf/7 dde/a Poza) 5f:

Sept 23, 1947- J. J. DE LA RozA, SR

SELF'CLEANING FLUID EXTRACTOR FOR HIGH CONSISTENCY Filed June 24, 1944 lll. I Il Jaa Arran/Ex Sept- 23, l947- J. J. DE LA RozA, SR

SELF-CLEANING' FLUID EXTRACTOR FOR HIGH CONSI-STENCY MIXTURES Filed Ju-ne 24, 1944 4 Sheets-Sheet 3 l 4 4 l. l

I INVENTOR. dodgy/f7 dde/a goza, 5f. 8% g H TT 01' NEY.

Sept. 23, 1947l q. q. DELA ROZA, ,SR- 2,427,662

SELF-CLEANING FLUID EXTRACTOR FOR HIGH \CONSISTENCY MIXTURES Filed June 24, 1944 4 Sheets-Sheet 4 I' I INVENTOR.'

dodgy/)7 (Zo/a Poza, 5'/- A T7' ORNE K Patented Sept. 23, 1947 UNlTED STATES PATENT OFFICE SELF-CLEANING FLUID EXTRACTOR FOR HIGH CONSISTENCY MIXTURES Claims.

This invention relates to improvements in uid extractors and refers more particularly to a mechanical device for the extraction of fluids from mixtures of high consistency. The device is nonclogging, permitting continuous operation.

Various means have been devised for the removal of fluids from solids and solids from fluids, the latter usually designated as a filtering device, as distinguished from an extractor or separator where the fluid is to be removed from the solid substance. Extractors and separators for removing fluids from solids usually employ pressure such as rotating rolls through which the material passes accompanied by the removal of uid as in the grinding of sugar cane in the manufacture of sugar or the dewatering of pulp in the manufacture of paper. The surfaces of the rolls varies, depending upon the purpose for which they are used, some rolls having a very coarse or striated or grooved or perforated periphery, while for other purposes relatively smooth surfaced rollsl are employed. The material of which the rolls are made is also governed by the uses metal, rubber and wood being typical of some of the substances employed. Besides the use of rotating rolls, other pressure devices include screw presses, utilizing the Archimedean screw principle, reciprocating piston presses and other types of mechanism through which the material is forced by mechanical pressure.

While the invention is here disclosed as used in conjunction with a piston press for removing fluid from brous material it is contemplated that it may be used also with any type of press for separating fluid from solids.

The principal difficulty experienced in separating fluids from solid material where high pressures are employed and high consistencies exist within the pressing Vessel is the clogging or obstructing of uid passageways by particles of the solid substance, and/or precipitates from the uid or gummy materials carried off in suspension with the fluid. The pressure at which presses can be operated without clogging is limited only by the strength of the press and the containing vessel or tube through which the mixture travels or by being rendered inoperative by clogging of the fluid removal parts. At high consistencies with certain substances such as cellulose friction between the mixture and the inside walls or casing abrades minute particles of the solid material which accumulate in the discharge orifices. The building up of these particles together with the presence of contaminants carried olf with the fluid has been one of the unsolved difficulties in the art of extracting fluids from high consistency mixtures. Attempts have been made to prevent clogging of the orifices in the handling of high consistency material by various methods including the design or shape of the orice, back washing and in filtration devices, sprays and Scrapers have been used to periodically clean the lter oriiices or passageways through which the fluid vis discharged. When mixtures of high consistency are being pressed through a continuous press to obtain the maximum degree of dryness (usually expressed in terms of percent on an oven-dry basis) extractors for such purposes have been limited in the pressures used to considerably below 1000 pounds per square inch in order to prevent clogging of the outward oriiices. The construction hereinafter described contemplates the use of pressures from 1500 to 2500 pounds per square inch or veven to 5000 pounds per square inch, or more, depending upon the materials andthe liquor removal required. Normally in the handling of cellulosic bers, petroleum products, and most other products, 2500 pounds per square inch will sufce to remove liquors to the maximum of somewhat below 60% on an oven-dry basis.

Obviously, the extremely high consistencies resulting from these high pressures require heavier design and construction than heretofore. Also where high temperatures or explosive or combustible'materialsare to be handled special heavy design and construction must be used. Likewise,

' the fluids being removed maybe of a very heavy viscous character such as the spent vliquors from the digestion of iibrous materials for the manufacture of cellulose pulp or the liquors used to convert cellulose bers into its derivatives as by treatment with concentrated alkalies or acids in the manufacture of viscose acetate, nitrocellulose and similar substances, or syrup in the manufacture of sugar, or ltrates in the manufacture of petroleum products.

The non-clogging continuous extractor described is intended to handle any type mixture of fluids and solids and effectively remove the uids from the solids beginning at the lower consistencies or dilutions and including mixtures of high consistency only limited by the capabilities of the press.

As the consistency or the relation of solid material to fluid present increases and the mixture becomes more dense, the tendency to clog orifices or drain ducts becomes an increasing diiculty. Consistencies of above 30% solids when passed through presses of the screw or reciprocating type rapidly clog drain orices of the conventional design making the press -entirely inoperative.

It is contemplated to use presses in tandem to perform a degree of extraction in the initial stage and further exhaust the fluid in subsequent stages. The removal of the liquid which increases the consistency of the mixture may be accomplished when acting on hot or cold mixtures or by passage of the mixture in one direction through the press or presses, or where the liquid is flowed countercurrently with the solid material.

Obviously the removal of fluids from solids by pressure requires that the surface screening of the solid mixture enables the fluid to emerge, retaining the solids within the pressure vessel and dislodge from the outlet orifices from the screen or extractor particles of the solids or precipitates carried off with the fluid. In the case of batch presses such as standard pulp presses employing mats or coconut fiber, wire or other means of retaining the solids, clogging is prevented as there is no continuous travel or motion of the solid material parallel to the confining walls. In the present type of press the material is moving continuously through a tube or casing mechanically urged by a reciprocating piston, screw drive or other propelling means.

Mixtures of high consistency such as cellulose pulp moved in this manner parallel to the plane of the extractor or screen have a tendency to plug outlet orifices which greatly increases as the consistency increases. This tendency to obstruct the outlets is aggravated by the abrasion of the cellulosic or other material, gums and other substances separated from the mixture or resulting from friction produced with the Walls of the surrounding vessel. Orices of various shapes and dimensions are all subject in a varying degree to plugging and obstruction. This clogging of the orifices has been the principal difficulty in the successful operation of a continuous high consistency press and has prevented the successful use of fluid extractors such as screw presses or reciprocating presses for the removal of solids at maximum consistencies above 40% solids on an oven-dry basis and especially presses operating on mixtures containing thick gummy substances such as the spent liquors from the digestion of fibrous materials for the manufacture of pulp and cellulose, solvents, reactants, catalysts and other liquors in the manufacture of petroleum and other products.

The invention lends itself particularly to the removal of decolorizing clays from mixtures of oil and clay or of the separation of clay from mixtures of solvents and clay or any separation of fluids and solids resulting in a mixture of a high solid consistency with the extraction of a large percentage of the fluid.

In the accompanying drawings which form a part of the instant specication and are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views,

Fig. 1 is a side view partly in section of a selfcleaning press and fluid extractor embodying the invention,

Fig. 2 is a view taken along the line 2-2 in Fig. 1,

Fig. 3 is a view taken along the line 3--3 in Fig. 2,

Fig. 4 is a view taken on the line 4-4 in Fig. 2,

Fig. 5 is a detail of the orifice plates and spacer members,

Fig. 6 is a sectional View of an extractor of modified construction in which the cleaning 4 plates slide longitudinally of the flow of the mixture,

Fig. '7 is a view taken along the line l-l in Fig. 6,

Fig. 8 is a second modification shown partly in section and in which the cleaning plates reciprocate transversely of the flow of the mixtlll'e,

Fig. 9 is a view taken along the line 9 9 in Fig. 8.

Referring to the drawings and particularly to Fig. l, and the construction shown in Figs. 1-5, at IIJ is a pressure cylinder in which a plunger or piston Il is reciprocated by a connecting rod I3. Material to be pressed is charged to the cylinder through an inlet I2. The mechanism for reciprocating the piston is omitted in the interest of simplicity as it is conventional in this type of press.

The press is designed for the removal of fluids from cellulose pulp made from wood, straw, bagasse or other fibers used in the manufacture of paper, cardboard and innumerable products manufactured from cellulosic materials. Such presses are also employed for the removal of solvents, reactants, catalysts or other fluids from solids in the manufacture of petroleum products or for other industrial purposes where it is desirable to extract fluids from mixtures of high consistency. Reciprocation of the piston II forces the mixture of fibrous material and fluid through the tubular passageway I4. While the invention will be explained in the treatment of cellulose pulp, it is adaptable as well for innumerable other uses where it is desired to separate fluids from mixtures of high consistency.

In the pressure duct I4 is positioned a constricting device or vane valve I5 held down by its weight plus a hydraulic piston I6, weighted levers, springs, mechanical screw or other means, to vary the size of the discharge opening and the pressure restricting the passage of the solids. The

g design of the valve is preferably according to construction disclosed and described in my co-pending application Serial No. 516,818 filed January 3, 1943. The size of the tapered nozzle I4 in the discharge end determines the consistency or density of the material forced through the nozzle by the reciprocating piston II. Centrally of the tube I4 are a plurality of extractors, three being used in the construction shown, although the number employed is not important as long as ample facilities are supplied for removal of the separated fluid.

The extractor construction consists of a body portion I1 having end flanges Ila which abut and are bolted to adjoining extractor flanges or flanges I4a of the pressure tube. Connected at the discharge end of the pressure tube is a repulper diagrammatically shown at I8. This mechanism as well as the reciprocating piston for moving material through the pressure tube and the constricting Vane valve I5 form no part of the present invention but serve merely as adjuncts to the apparatus employed in the manufacture of pulp and are illustrated in an operable combination with the extractors to facilitate an understanding of their use and construction. In cases where repulping is not desired the repulper is of course omitted. In the construction shown in Figs. 1-5 inclusive, the extracting devices are positioned within and form a part of the pressure tube. Mixtures passing through the extractors and pressure tube are compressed to an increasingly higher Consistency as they move slowly therethrough. The walls of. the;extractor'haveLnarrow elongated slotted' orifices. of aA dimensionY which permits free passage of fluid, but screen. or ob.- struct the passage of solid material` of normal appreciable size. ThereV isprovision for draining olf the fluids which enter these narrow-orifices and reciprocated in the slots orV narrow passages are a plurality of blade-like cleaning plates. The cleaning plates during. their reciprocation ad'- vance until. their edges are flushv with orA coincide with the wall of the passageway thro-ugh which the mixture is being forced andv when retarded allow free flow of uid through the orifices to the drain. Thus clogging of'` the passageway by` solid particles. or contamina-ntssuspended or pr cipitated.' from. the iluid is prevented. An opening is provided oppositeV and in alignmentwi-th the drain 35 asshovvnirl-Fig.` 2. to facilitate peri.- odic cleaning of the drain passageway.

In. the construction shown in Figs. 1-5` the cleaning plates are reciprocated transversely to the ow of travel of the mixture through the tube. While the passageways in the drawings are shown in the side walls of the extractor unit they may be positioned in the four walls ofthe rectangular shaped tube or in the upper and lower walls instead of the sides. Novelty resides in the cooperative functioning ofthe high consistency pressing and filtering and in cleaning mechanism and passageways rather than the location of the passageways in the pressure tube.

Describing now` the details of the mechanism, within the bodies I1 of the respective extracto-r units are positionedla plurality of U-shaped orice plates I9 detailed in Fig. 5. The slots 2U between the orifice plates are formed by spacers 2|. This assembly of orice plates and spacers are held together within the extractor body by bolts 22. The reciprocating assembly for cleaning the orifices 20 comprise blades 23 mounted between blocks 24 which have thin shims or gaskets 25 on opposite sides of the blades andv between the blocks to hold the blades centrally within the orifices. Blocks 24Y whichv mount the cleaning blades therebetween are tied together as a unit by means of bolts 2E. This unit is reciprocated by rod 2.1. screwed into. the central block and is threaded at its outer end to receive the internally threaded gear 28 which meshes with the rack 29. Gear 28 has a flanged portion 28a which bears in a support 30. This support is bolted to the side of the extractor and also carries the hanger 3l in which rack 29 slides. Surrounding the rod where it enters the extractor body is a stulng box 32. All of the three extractors shown in Fig. 1 being identical in construction, the description of a single extractor will sufce. Instead of gear 28 the blades may be actuated by other suitable means.

Reciprocation of the cleaning blades within the slotted orifices is accomplished by rod connection 33 between piston rod I3 and rack 29. Reciprocation of the rack drives gears 28 with which it meshes and the gears in turn advance and retard rods 21. The movement of the rods is transmitted to the cleaning blades and as a consequence the blades are oscillated back and forth in the fluid discharge orifices, once for each stroke in a reciprocating press. The open space formed behind the U-shaped oriiice plates I9 furnishes drainage through the extractor body to duct 34 and drain pipe 35.

Describing now the modified construction shown in Figs. 6 and 7 which diiers from the construction Of Figs.- 1 5 .principally in that the cleaning bladestravel: parallel. to the flow of the material through the` pressuretube and friction noz- Zle insteadcf transversely thereto. The side sectional view Fig. G'is. shown in a somewhat smaller scale than the transverse section shownin Fig. 7';

consequently,V the.l passageway for the materiali and theV partsof the extractor appear somewhatl smaller. As in the preceding figures the orice plates I9 are held apart by spacers to form the slot-like passageways for removal` of the fluid.

Cleaningv blades. 23 are mounted between blocks:V

24wwhich have shims or gaskets 25 on opposite sides of the blades. The assembly is held together as a unit by bolts'ZE' and i-s reciprocated by recip ings in the interest of simplicity. This drive` moves the rod in one direction until the blades have travelled across the orifice opening and is then reversed to reciprocate the cleaning assembly toits original position. Thus, during a complete cycle the blades are moved longitudinally of the oriiice openings so that the front edges of the blades will clean the slits or orifices in the walls of the extractor which confine the high consistency mixture, Drain ductV 34 removes uid passing from the pressure tube into the orifice slits out through drain pipe 35.

In the modiiication shown in Figs. Sand 9 orice plates I9 have a plurality of small apertures or drains 36a along their edges which formA a portion of the` walls of the pressure tube. These drain holes in the superposed orifice plates register to forma continuous duct and with the ducts 34 in the shell of the extractor. Fluid drained through these ducts is discharged through manifold 35.

The unit making up the cleaning assembly in thisv modification comprises ay plurality of horizontal plate-like blades 23, as before, which reciprocatein the orifice slits. The blades in this particular modication are mountedupon bars or rod-like support members 26a which have a similar function to the stay bolts or tie rods which unite the blade cleaning assembly unit in the modifications shown in Figs. 1 to '7, inclusive. In this modification travel of the cleaning blades is transverse to the flow of mixture to be extracted as in the construction shown in Fig-s. l to 5, inclusive. The single rod 2T shown in the construction depicted in Figs. l to 5, inclusive, in this modification is replaced by a double rod 21a driven by crosshead or yoke 35 actuated from any convenient reciprocating source of energy7 through drive rod 31. The driving mechanism for the cleaning blades has been likewise omitted here as in the previous modification.

To permit reciprocation of the vertical support rods 26a with their attached cleaning plates or blades, orifice plates I9 are slotted as shown at I9a in Fig. 8. Stufling boxes 32 surround rods 26a to prevent leakage. Plugs 38 close holes through the housing opposite the ends of the support rods 26a. Plugs 39 close holes through the housing which register with the drain ducts through the orifice plates to facilitate cleaning.

The operation of this modification is the same as that described in Figs. 1 to 5, inclusive, the cleaning blades in their reciprocation through the orifices removing solids or gummy material which enter from the pressure tube with the iiuid.

As previously suggested, the uid extractors described are not to be confused with filtering devices Where relatively small quantities of solids are to be separated from relatively large quantities of fluids. It is the -purpose of these extractors to effectively remove fluids from mixtures of high consistencies where high pressures are employed to press the fluid from the mixture in order to obtain a relatively dry resultant product. The extractors are adaptable for use with continuous presses of the reciprocating or screw type where the fluid-solid mixture is being continuously forced under high pressure through a tubular passageway though it be circular, rectangular or other shape in cross section and the fluid is removed during its travel through said passageway.

From the foregoing it Will be seen that the invention is one well adapted to attain al1 of the ends and objects hereinbefore set forth together with other advantages which are obvious and which are inherent to the structure.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

l. An extracting device for separating fluids from high consistency fluid-solid mixtures including a pressure duct through which the mixture is mechanically propelled, the improvement which resides in means providing apertures along said pressure duct, and reciprocating cleaning members in the apertures, whose edges adjacent the pressure duct have an extreme position flush with the inner surface of the pressure duct adapted to dislodge accumulated substances and permit free flow of fluid therethrough.

2. An extracting device for separating fluids from high consistency uid-solid mixtures including a pressure duct through which the mixture is mechanically propelled, the improvement which resides in means providing narrow slotted apertures along said pressure duct, and reciprocating cleaning members in the apertures moving transverse to the pressure duct, whose edges adjacent the pressure duct have an extreme advanced position flush with the inner surface of the pressure duct to dislodge accumulated substances and permit free ilow of fluid therethrough.

3. An extracting device for separating fluids from high consistency Huid-solid mixtures including a pressure duct through which the mixture is mechanically propelled, the improvement which resides in means providing narrow slotted apertures along said pressure duct, and reciproeating cleaning members in the apertures moving parallel to the pressure duct, whose edges adjacent the pressure duct are flush with the inner surface of the pressure duct during their reciprocation to dislodge accumulated substances and permit free flow of fluid therethrough.

4. An extracting device for separating fluids from high consistency solid mixtures including a pressure duct through which the mixture is mechanically propelled, the improvement which resides in means providing narrow slotted passageways along said pressure duct, and reciprocating cleaning members in the passageways, whose edges adjacent the pressure duct have an extreme position flush with the inner surface of the pressure duct to dislodge accumulated substances and permit free ilow of fluid therethrough, and drainage ducts between the slotted passageways to remove separated fluid.

5. An extracting device as in claim 1 in which a restricting valve is mounted in the discharge of the pressure duct whereby the consistency of the discharged material may be regulated.

JOAQUIN J. DE LA ROZA, SR.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,877,449 Fulcher Sept. 13, 1932 2,321,786 Wotton June 15, 1943 1,971,546 Tuttle Aug. 28, 1934 1,977,145 Ragsdale Oct. 16, 1934 1,977,259 Anderson Oct 16, 1934

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