US2860973A

US2860973A - Pulp stock thickener

Info

Publication number: US2860973A
Application number: US631625A
Authority: US
Inventors: Wells Roger
Original assignee: Diamond Gardner Corp
Current assignee: Diamond Gardner Corp
Priority date: 1956-12-31
Filing date: 1956-12-31
Publication date: 1958-11-18
Anticipated expiration: 1975-11-18

Description

Nov. 18, 1958 R. WELLS PULP s'rocxTHICKENERv Filed nec. s1, 195e INVENTOR BY ik ATTORNEY AThis invention relates to apparatus 'for' separating Vex- Inthe'inah'ufaeture "et 'paperinii "many molded pulp articles, such as4 egg eiton's, 'pie plates, 'and 'the like,

Hit is "customary/'to employ ap'ulp slurry comprising a "dilutegliquid s`1`1's'pe'sio`nV of Vpulpbers ya'sfthepulp stock :in suctionlrnolding npera'tins to produce the pulp articles desired. Frequently, it is Wnecessary Atothik'e'n the pulp 'slurry, by separating'excess liquid'r'om the lpulp iibers, incident to Ivarious washingoper'ations and changes in chemical treating agents, during the preparatory treatment of the pulp stock. A thickeningtrea'trnent may also be employed in the recoveryfof waste pulp from the so- A'called lwhite liquor or mill 'eiuent Heretofore, the type of y apparatus 'employed'rnost frequently fory thickening 'the pulp stock ,has been va foraminous'suction roll mounted rotatably partially submerged in apulp slurry tank and connected by suitable ypipesto a Vsuction pump.V The Yapplication of suction to the roll causes wet pulp -fibers to be extracted from the rpulp slurry and depositsthese `fibers in a'layer on the ysurface of the roll.l This'layer offpulpiibers isv advanced continuously during rotation ,of theuroll to a doctor blade or a brushv type take-oil, roll mounted adjacent to an apronwhere thebers are washed into a container by a H suitable spray of water. 'I he thickening apparatus known heretoforerequired complicatediequipment which was expensive toinstall and operate.

An object ofI the present invention `is` to provide new -and improved apparatus for thickening ,pulp stock.

Anotherobjectof the linvention is to-provrde a-simplilied vacuumless apparatus for separating excess liquid from librous suspensions. l l j Still another vobject-of,the'inventionvis to provide a 'simplied apparatus for thickening pulp stock and wash- -ing the pulp bers therefrom withoutemploying auxiliary spraying equipment. 1 v 4 y Other objects 'and-the Inature'and advantages of the invention. will be apparent from the following descripyti'on'taken in conjunction ,with thev accompanying drawing, .wherein .United Safes Peten-f o The single ligure is-aschematic showing'in vertical sec- I e' tional view` of a pulp 4stockthickening apparatus embodying the invention. i

'The apparatus villustrated includes a 4massive, e cylindrical, spongy rtype roll `1 -havingia solid lmetallimcore 2 `ijournalled for rotation-inthe :side walls of van'open tank 3 containing pulpfslurry, This fpulp slurry'may contain, for example, from about 1% to about 3% by'fweight of pulp bers Vsuspended inwater.y They roll1 is mounted partially submerged in thelpulp'slurry, rand during rota- "tion of'the'roll successive portions thereof-:are advanced "through the slurry for the purpose of absorbing the liquid therefrom r'The spongy. roll 1-1 composed yofa suitableabsorbent `resilient material, such as sponge rubber. Either natural rubber in cellular form, or synthetic foamed rubbery materials may be used, such as lpolyurethane foam. In any event, the roll 1 must be durable, resilient, tough, and "capable of absorbing a relatively large quantity of liquid. The roll 1 may be built around the core 2 by inserting the core into a large cylindrical body of sponge rubber, or by wrapping a thick sheet of sponge rubber around the core, vor by securing a series of spongy pads to the periphery of the core.

A compression or squeezevroll 4 isjournalle'd for rotation in the side walls of the tank 3, at approximatelyy the upper level of the pulp Aslurry contained therein, 'and in compressing engagement with the spongy roll 1 alongr the entire length thereof. Duringl rotation of the spongyroll 1 the squeeze roll 4 is rotated therewith, due to the frictional contact between these rolls. As the result of this motion, successive portions of the periphery of the spongy Vroll 1 are compressed as they` enter the pulp slurry, and -these portions are allowed to re-expand beneath the surface of the slurry, thereby sucking liquid from the slurry bya sponging action. The cellular structure of the spongy roll 1 should'be sufficiently line to cause the pulp bers to be deposited in a thick layer 5 on the periphery of the 1 roll 1, while the liquid extracted therefrom is sucked into the interior ofrthis roll during re-expansion of the compressedt portions thereof.

fAfter'the re-expanded portions of the periphery of the vspongy -roll 1 have advanced through an arc of about 1270 beyond the squeeze roll '4, they are again compressed by a take-off roll 6 mounted rotatably in compressing contact with the roll 1 along the entire length thereof. The take-oil'roll 6 indents the spongy roll 1 sufficiently to squeeze a small portion of the water therefrom. The water expressed by the take-oil roll 6 washes off the layer 5 of pulp fibers deposited on the periphery of the roll 1. A doctor blade 7 scrapes the wet pulp bers fromthe take-oit roll 6, from whence the pulp "bers'slide down an inclined apron 8 into a suitable chest '9. The wet pulp stockdischarged into the chest 9 may containfrom about 50% to about 80% by weight of "pulp fibers.

The successively compressed portions of the periphery Vof vthe spongy roll 1 are allowed to re-expand after they Yadvance past the take-off roll 6, until they again reach "the squeeze roll 4, which then compresses these'portions to a much greater' extent than did the lroll 6, thereby expressing the remainder of the water from these portions of the roll 1. The/water expressed by the squeeze roll 4 is removed therefrom Vby-a doctor blade 10, and allowed to iio'w down an inclined apron 11 intoa drain troughlZ.

At this point in the rotation of the rolll ythesponging cycle of compression and expansion starts again.

The squeeze roll 4 and the take-oit roll 6 are both made of `a corrosion resistant, Wear resistant, hard material, such as bronze or steel. The squeeze roll -4 is made considerably larger in'diameter than is the take-off -roll"'6, -in

order tocompress the spongy roll l'to a greater'extent. Driving means (not shown) Imay be peratively connected to thev take-off roll 6 to iin'p'artrotation to the three rolls 1, 4 and 6.

It isr evident thatapparatus embodying the yinvention provides avery simpleand effective means for thickening force which can be-created bycompression'and expansion fof the spongy roll is. greater than cannormallybe obtained from aconventionalfscreen covered cylinder ro1l,`whichjis dependent lupon adiierence in the levels oftheistock.v

Another important advantage y of apparatus Nembodying the invention is the elimination of a water spray to wash the pulp fibers from the take-off roll. It is also contemplated that the simple construction of this apparatus may enable it to be made portable, thereby providing `other practical advantages.

It will be obvious to those skilled in the art that various changes may be made Without departing from the spirit of the invention, and therefore the invention is not limited to what is shown in the drawing and described in the specification, but only as indicated in the appended claims.

What is claimed is:

l. Apparatus for extracting excess liquid from dilute liquid suspensions of fibers, comprising a massive spongy roll composed of an absorbent resilient material mounted rotatably partially submerged in such a suspension, means for compressing successive portions of the periphery of the roll as they enter the suspension during rotation of the roll, which portions are allowed to re-expand beneath the surface of the suspension thereby extracting fibers from the liquid and depositing the fibers on the periphery of the roll, and take-off means mounted in partially cornpressive contact with said periphery for removing the deposited fibers from the roll after they have emerged from the suspension.

2. Apparatus for extracting excess liquid from dilute liquid suspension of fibers, comprising a massive spongy roll composed of an absorbent resilient material mounted rotatably partially submerged in'such a suspension, a squeeze roll mounted rotatably in engagement with the spongy roll for compressing successive portions thereof as they enter the suspension, which portions are allowed to re-expand beneath the surface of the suspension thereby extracting fibers from the liquid and depositing the fibers on the periphery of the roll, and take-ofi means mounted in partially compressive contact with said periphery for removing the deposited fibers from the roll after they have emerged from the suspension.

3. Apparatus for extracting excess liquid from dilute liquid suspensions of fibers, comprising a massive spongy roll composed of an absorbent resilient material mounted rotatably partially submerged in such a suspension, a

squeeze roll mounted rotatably in engagement with the` spongy roll for compressing successive portions thereof as they enter the suspension during rotation of the roll, which portions are allowed to re-expand beneath the surface of the suspension thereby extracting fibers from the liquid and depositing the fibers on the periphery of the roll, and a take-off roll mounted rotatably in engagement with the spongy roll for removing the deposited fibers from the spongy roll after they have emerged from the suspension.

4. Apparatus for extracting excess liquid from dilute liquid suspensions of fibers, comprising a massive sponge movable through such a suspension, means for compressing successive portions of the sponge as they enter the suspension, Iwhich portions are allowed to re-expand beneath the surface of the suspension thereby extracting fibers from the liquid and depositing the fibers on the surface of the sponge, and take-off means mountedin partially compressive contact with said surface for removing the deposited fibers from the sponge after they have emerged from the suspension.

5. Apparatus for extracting excess liquid from dilute liquid suspensions of fibers, comprising a massive sponge movable through such a suspension, a squeeze roll mounted rotatably in engagement with the sponge for compressing successive portions thereof as they enter the suspension, which portions are allowed to re-expand beneath the surface of the suspension thereby extracting fibers from the liquid and depositing the fibers on the surface of the sponge, and take-off means mounted in partially compressive contact with said surface for removing the deposited fibers fromA the sponge after they have emerged from the suspension, l v

6. Apparatus for extracting excess liquid from dilute liquid suspensions of fibers,comprising a massive sponge movable through such a suspension, a squeeze roll mounted rotatably in engagement with the sponge for compressing successive portions thereof as they enter the suspension, which portions are allowed to re-expand beneath the surface of the suspension thereby extracting fibers from the liquid and depositing the fibers on the sponge, and a take-ofi roll mounted rotatably in compressing engagement with the sponge for removing the deposited fibers from the sponge after they have emerged from the suspension.

7; Apparatus for .separating excess liquid from dilute liquid fibrous suspensions, comprising a massive spongy roll composed of an absorbent resilient material mounted rotatably partially submerged in such a suspension, a squeeze roll mounted rotatably in compressing engagement with the spongy roll at approximately the uppen4 level of the suspension for compressing successive portions of the periphery of the spongy roll as they enter the suspension during rotation of the roll, which portions are allowed to re-expand beneath the surface of the suspension thereby extracting fibers from the liquid and depositing the fibers on the spongy roll, and a take-off roll mounted in compressing engagement with the spongy roll above the upper level of the suspension, said takeoff roll compressing the spongy roll sutiiciently to express a small portion of the liquid absorbed therein to wash the deposited fibers from the periphery of the spongy roll.

8. The apparatus defined by claim 7, wherein the takeolf roll issmaller in diameter than the squeeze roll, and these rolls are mounted approximately 270 apart on the periphery of the spongy roll.

9. Apparatus for thickening pulp stock, comprising a massive sponge rubber roll mounted rotatably partially submerged in a dilute water slurry of pulp stock, a squeeze roll mounted rotatably in compressing engagement with the sponge roll at approximately the upper level of the slurry for compressing successive portions of the periphery of the sponge roll as they enter the slurry during rotation of the roll, which portions are allowed to re-expand beneath the surface of the slurry thereby extracting pulp fibers from the water and depositing the fibers on the sponge roll, a take-off roll mounted in compressing engagement with the sponge roll above the upper level of the slurry, said take-off roll compressing the sponge roll suiciently to express a small portion of the water absorbed therein to wash the deposited fibers from the periphery of the sponge roll, and a pair of doctor blades mounted adjacent to the squeeze roll and the take-off roll for removing excess water and wet pulp fibers, respectively, from these rolls.

l0. The apparatus defined by claim 9, wherein the take-oli roll is smaller in diameter than the squeeze roll, and these rolls are mounted approximately 270 apart on the periphery of the sponge roll.

11. A method of thickening a thin liquid slurry of fibrous pulp stock, comprising the steps of continuously advancing a massive sponge into such a slurry to mmerse successive portions of the sponge therein, continuously compressing said portions of the sponge as they enter the slurry while permitting said portions to reexpand within the slurry, thereby soaking up liquid from the slurry in the interorof the sponge and depositing extracted pulp bers on the surface of the sponge, advancing said vportions of the sponge out of the slurry, and

then removing the deposited fibers from the surface ofy the sponge.

12. A method of thickening a thin liquid slurry of fibrous pulp stock, comprising the steps of continuously advancing a massive sponge into such a slurry to immerse successive portions of the sponge therein, continuously compressing said portions of thesponge as they enter the slurry `while permitting said portions to re-expand within the slurry, thereby soaking up liquid from the slurry in the interior of the sponge and depositing extracted pulp bers on the surface of the sponge, advancing said portions of the sponge out of the slurry, and then partially compressing said portions of the sponge to express sucent liquid from its interior to wash oi the deposited fibers from its surface.

References Cited in the le of this patent UNITED STATES PATENTS

Claims

1. A APPARATUS FOR EXTRACTING EXCESS LIQUID FROM DILUTE LIQUID SUSPENSIONS OF FIBERS, COMPRISING A MASSIVE SPONGY ROOO COMPOSED OF AN OBSORBENT RESILIENT MATERIAL MONTED ROTATABLY PARTIALLY SUBMERGED IN SUCH A SUSPENSION, MEANS FOR COMPRESSING SUCCESSIVE PORTIONS OF THE PERIPHERY OF THE ROLL AS THEY ENTER THE SUSPENSION DURING ROTATION OF THE ROLL, WHICH PORTIONS ARE ALLOWED TO RE-EXPAND BENEATH THE SURFACE OF THE SUSPENSION THEREBY EXTRACTING FIBERS FROM THE LIQUID AND DEPOSITING THE FIBERS ON THE PERIPHERY OF THE ROLL, AND TAKE-OFF MEANS MONTED IN PARTIALLY COMPRESSIVE CONTACT WITH SAID PERIPHERY FOR REMOVING THE DEPOSITED BIERES FROM THE ROLL AFTER THEY HAVE EMERGED FROM THE SUSPENSION.