US3771732A

US3771732A - Pulper

Info

Publication number: US3771732A
Application number: US00273135A
Authority: US
Inventors: E Cumpston
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-07-19
Filing date: 1972-07-19
Publication date: 1973-11-13
Anticipated expiration: 1990-11-13

Abstract

A pulper uses a stator having a ridged peripheral surface and a rotor adjacent the stator and having a peripheral rim with a ridged surface confronting the ridged surface of the stator. Spokes extend from the rotor''s central region to support the rim and provide a substantially open, annular region radially inward from the rim. A cleaner is spaced over the open region and preferably includes cleaning vanes allowing only clean pulp to enter the open region between the spokes to be pumped out through the ridged surfaces of the rotor and stator.

Description

United States Patent [191 Cumpston, Jr.

[ Nov. 13, 1973 PULPER [76] Inventor: Edward H. Cumpston, Jr., 43

Monument Ave., Old Bennington, Vt. 05201 [22] Filed: July 19, 1972 211 Appl. No.: 273,135

[52] [1.8. CI 241/46.11, 241/97 [51] Int. Cl. B02c 13/18 [58] Field of Search 24l/46.06, 46.11,

[56] References Cited UNITED STATES PATENTS 2,129,789 9/1938 Seaborne 241 97 3,380,669 4/1968 Hatton 241 97 x 2/l969 Moulton 4/1970 Cumpston ..241/97 3,713,595 1/l973 Craig et al. 241/46.ll

Primary Examiner-Granville Y. Custer, Jr. Attorney-Cumpston, Shaw & Stephens [57] ABSTRACT A pulper uses a stator having a ridged peripheral surface and a rotor adjacent the stator and having a peripheral rim with a ridged surface confronting the ridged surface of the stator. Spokes extend from the rotors central region to support the rim and provide a substantially open, annular region radially inward from the rim. A cleaner is spaced over the open region and preferably includes cleaning vanes allowing only clean pulp to enter the open region between the spokes to be pumped out through the ridged surfaces of the rotor and stator.

,36 Claims, 5 Drawing Figures PULPER THE INVENTIVE IMPROVEMENTS This invention is an evolutionary advance from the pulper shown in US. Pat. No. 3,506,202. The invention involves discovery of several problems and inadequacies of the previous pulser, and a realization'that these problems and inadequacies can be solved by a different construction leading to a different operational mode and providing faster and more efficient pulping. The improved pulper of this invention aims at efficiency, reliability, economy, and safety, and it improves on the previous pulper in achieving better cleaning of the pulp admitted to the rotor, faster and more efficient pulping, improved defibering of pulp, and more economical and reliable construction.

SUMMARY OF THEINVENTION The inventive pulper uses a stator having a ridged surface on a peripheral annular region and a rotor adjacent the stator. The rotor has a peripheral rim supported by spokes to provide a substantially open annular region radially inward from the rim. A ridged surface on the rim confronts the ridged surface of the stator, and a cleaner is spaced over the open region.

BACKGROUND OF THE INVENTION The pulper described in US. Pat. No. 3,506,202 was .not very successful, but its deficiencies inspired this invention. For example, the pulp outletformed as holes in the stator was inoperable becauseof the high vacuum created by the pumping action between the rotor and the stator. When the outlet valve was opened, air rushed into the pulper rather than pulp flowing outward. Also, the holes in the stator refining surface greatly reduced its efficiency.

The inlet holes in the rotor quickly plugged up when foreign matter was present in the pulp, and modifications attempting to overcome this were expensive and complex and involved cleaning vanes and shrouds arranged around the bonnet and having different configurations depending upon their position relative to the inlet holes through the rotor.

The original intention in the previous pulper was that since cleaning of the pulp to keep foreign objects out of the rotor inlet could not be complete and "reliable, the inlet openings should be spaced as closely as possible to the attrition zone of the pulper so that any foreign material such as ropes or strings entering the rotor inlet openings would be quickly chewed up in the attrition ridges and not allowed to hang up in the rotor and clog itsintake openings. This consideration involved design limitations that created many problems making the prior pulper a poor compromise.

After experience with cleaning techniques for a rotor, it was discovered that a very reliable cleaner could be made that would keep foreign objects out of the rotor inlet. Also, the need was recognized for opening up and expanding the rotor inlet to accommodate a greater volume and make the inlet less susceptible to through the rotor. For strength the spokes extend axially of the rotor a considerable distance, and this spaced the inlet cleaner a long way from the attrition zone under the annular box used as a rotor rim. This would normally be undesirable and would invite hanging up of foreign material in such a long passageway, but a better cleaner was devised for those installations where dirty pulp is encountered so that the rotor inlet could be kept clean.

In addition, a better way was devised for forming the ridged attrition surfaces of the rotor and stator, and the entire construction was simplified and strengthened. For example, the earlier pulper used a two and one half inch thick, stainless steel disk which was heavy, unwieldy, and expensive, while the inventive pulper uses a stronger but simpler and lighter construction.

Finally, the inventive improvements were found to make the pulper run cleaner and safer, to do a better job'of defibering the pulp, and to run at a greatly increased capacity for more efficient operation.

DRAWINGS FIG. 1 is a partially schematic, cut-away, side elevational view of a preferred embodiment of the inventive DETAILED DESCRIPTION Pulper 10 of FIG. 1 includes a tank 1 1 having a stator 12 and a rotor 13 turned by drive shaft 14 all as generally known. Rotor 13 and stator 12 can be in the side wall of tank 11 as illustrated, or can be mounted in the bottom of tank 11. Also, more than one rotor 13 can be operated in a single tank 11 if desired.

The improvement'in the inventive pulper lies chiefly in the construction of the rotor and stator so that these cooperate in an improved fashion for a more efficient and satisfactory pulping. A preferred construction of the rotor and stator isbest shown in FIGS. 2 5.

As best shown in FIGS. 2 and 3, a hub 15 is secured to shaft 14 to support rotor 13 which has a central region constructed of 'a disk 38 secured to hub 15 and carrying a cylinder 16. Radial spokes 17 formed as axially oriented plates extend radially outward from cylinder l6, and an annular rim 18 is supported on spokes 17. Rim 18 is formed ofan inner cylinder 19 secured to spokes17, an axially inner annular plate 20, an axially outer annular plate 21, and an .outer cylinder 22 joined together to form an annular box supported by clogging. Pumping was found to occur mostly around I the peripheral region of the attrition zone, so it was important to keep the peripherally outer ridges uninterrupted.

' After much work on these discoveries, an inventive concept was derived to form the rotor asa rim supported by radial spokes to allow a large, open inlet spokes 17. The box formed by

plates

20 and 21 and cylinders l9 and 22 is preferably closed and its strong and strudy but relatively lightweight.

Stator 12 and rotor 13 each have ridged, peripheral surfaces described more fully below to form an attrition zone 23 through which pulp is radially pumped for defibering. Since stator 12 and rotor 13 have a fairly large diameter of, for example, four to five feet, pumping is very forceful through attrition zone 23 and creates a high vacuum between rotor 13 and stator 12. This tends to draw rotor 13 toward stator 12 and to bend or deform rotor 13 slightly in an umbrella fashion. Rotor 13 is preferably strong and rigid to resist such a deforming force, and its strength lies in a strong central region using disk 38 and cylinder 16, sturdy spokes 17, and a strong annular rim 18 formed as a closed box. Spokes 17 extend axially for a sufficient depth to support rim 18 rigidly, and the minimum axial dimension of spokes 17 is preferably at least 6 percent of the outside diameter of rotor 13. The spaces between spokes 17 then afford a generally open and unobstructed passageway through rotor 13 radially inward from rim 18 without a sacrifice in rotor strength.

A cleaner formed of an annular cover plate 24, spaced-apart cleaning vanes 25, and an annular rim plate 26 is arranged over spokes 17 for keeping foreign matter out of the inlet through rotor 13 in the spaces between spokes 17. Vanes 25 are preferably welded between rim plate 26 and cover 24 to form a cleaner assembly that is clamped down under center plate 27. Cover 24 preferably extends radially outward beyond the inner perimeter of rim plate 26 so that pulp material entering between spokes 17 must flow radially inward against the outward pumping force of rotor 13. This tends to keep foreign objects out of the rotor inlet to keep the pulper clean and protect the attrition zone 23, and for some installations where relatively clean pulp is used, cover 24 is sufficient protection for the rotor inlet.

In many circumstances, foreign matter such as rope, string, and debris gets into pulper l and must be kept out of attrition zone 23 if possible. Whenever such foreign matter is expected, the whole cleaner assembly including cover 24, cleaning vane plates 25, and rim plate 26 is preferably clamped in place under plate 27 to guard the rotor inlet opening. An outer rim plate 39 carries mixing vanes 28 for pumping and mixing pulp, and inner rim plate 26 preferably interlocks with outer rim plate 39 to help secure the cleaner in place. Each of the cleaning vanes is preferably formed as a flat, parallelogram plate, and since cover 24 and rim plate 26 are parallel, a plurality of identical cleaning vane plates 25 can be conveniently welded between cover 24 and plate 26.

Cleaning vane plates 25 are preferably angled at about 45 to the radius of rotor 13 and about 45 to the axis of rotor 13 as illustrated, and are oriented to have outwardly trailing edges relative to the direction of rotation of rotor 13, as best shown in FIG. 3. Vanes 25 then pump outwardly as rotor 13 rotates, and pulp drawn into the inlet spaces between spokes 17 in response to the pumping force through attrition zone 23 must move inwardly around cleaning vanes 25 which are very successful in keeping foreign objects out of the rotor inlet and admitting only clean pulp. This keeps the inlet clear and unclogged, and prevents any damage to the attrition zone 23. It also leaves foreign objects whole and unbroken so that they can be removed from tank 11 rather than chewed up to contaminate the ulp. p The space between rim plate 26 and cover 24 can range from 1 inch 6 inches, and cleaning vane plates 25 are preferably spaced from 3 to 12 per foot of outside diameter of rotor 13, depending in part on the expected cleanliness of the pulp to be worked in pulper 10. The cleaning effect of cover 24 and cleaning vanes 25 is good enough to keep the rotor inlet unclogged,

even though there is a considerable distance between cleaning vanes 25 and attrition zone 23. At the same time, the generally open and unobstructed spaces between spokes 17 allow a high volume intake through rotor 13 to meet the high volume and forceful pumping through attrition zone 23. The result is not only a faster and more efficient pulper, but a pulper that keeps itself clean and safe and does not clog up, damage itself, or shred contaminants into the pulp.

As added insurance that foreign material does not plug up rotor 13 or lodge in the space between rotor 13 and stator 12, stator 12 has a few radial bars 40 confronting rotor 13, and rotor 13 has a few radial bars 41 arranged under annular plate 42 to confront stator bars 40. The relative motion between rotor 13 and stator 12 moves bars 40 and 41 across each other to break up any foreign material and keep it from lodging in place.

Attrition zone 23 is formed in an improved way of sector plates 30 as best shown in FIGS. 2, 4 and 5. Sector plates 30 are preferably equal, angular portions of the annular attrition zone 23, and are preferably identical for both stator 12 and rotor 13. Each sector plate 30 has generally radial ridges 31 oriented to pump radially outwardly, and sector plates 30 are preferably cast of hard, metallic material. The bases of sector plates 30 preferably have a potted coating 32, formed of a plastic or moldable material such as epoxy. Potted coating 32 is preferably applied to each of the sector plates 30 in a single mold so that the bases of each sector plate are identical for uniform and firm clamping of sector plates 30 in place.

The outer rim of both the rotor and stator has a peripheral abutment surface formed as a groove 33 that is dove-tailed in shape to fit the dove-tail shape of the potted coating 32 of sector plates 30. Grooves 33 provide a firm abutment surface holding sector plates 30 against centrifugal force. The radially inward edges of sector plates 30 are also dove-tailed, and are held in place by clamp rings 34 that have a matching dove-tail and are wedged in place between sector plates 30 and cylindrical ridges 35 and held tight by screws 36. Clamp rings 34 wedge down the inner edges of sector plates 30 tightly and hold sector plates firmly between the dove-tail of groove 33 and the dove-tail of clamp ring 34. This arrangement also facilitates changing or replacing sector plates 30 if they are worn or damaged, and it allows the entire attrition zone 23 to be formed of a number of identical plates that are readily molded and provided with potted base coatings 32.

The inventive pulper solves the problems encountered by the pulper described in U.S. Pat. No. 3,506,202, and is also far more efficient and economical. It forcespulp through its attrition zone at a much higher rate, partly because its attrition zone is uninterrupted, its intake is open and commodious, and its intake cleaner is efficient and reliable. Also, its construction is stronger, lighter, and less expensive. Hence, it is cheaper to build, more reliable in operation, and does a faster and better job. It is also easier to service and maintain, and more versatile in the pulp it can work. it does a better and faster job of defibering pulp, and it does not choke or clog on contaminants or chew them into bits disbursed into the pulp.

Persons wishing to practice the invention should remember that other embodiments and variations can be adapted to particular circumstances. Even though one point of view is necessarily chosen in describing and defining the invention, this should not inhibit broader or related embodiments going beyond the semantic orientation of this application but falling within the spirit of the invention. For example, those skilled in the art will appreciate the many sizes, shapes and constructions possible to adapt the inventive pulper to various circumstances.

I claim:

1. An improved pulper comprising:

a. a stator having a ridged surface on a peripheral annular region; r

b. a rotor adjacent said stator;

'c. a shaft for driving said rotor;

d. means for supporting the central region of said rotor on said shaft;

e. said rotor having a peripheral rim;

f. spokes supporting said rim on said central region to provide a substantially open, annular region radially inward from said rim;

g. a ridged surface of said rim confronting said ridged surface of said stator; and

h. a cleaner spaced over said open region.

2. The pulper of claim 1 wherein said spokes are plates extending radially and axially of said rotor.

3. The pulper of claim 2 wherein said spokes extend for an axial distance of at least 6 percent of the outside diameter of said rotor.

4. The pulper of claim 2 wherein said cleaner and said ridged surface of said rotor are spaced axially on opposite sides of said spokes. I

5. The pulper of claim 1 wherein said cleaner includes vanes. v p

6. The pulper of claim 5 wherein said vanes are inclined approximately 45 to the axis of said rotor and approximately 45 to the radius of said rotor and oriented to have outwardly trailing edges relative to the direction of rotation of said rotor.

7. The pulperot claim 5 wherein said.cleanerincludes a cover. extending radially outward beyond the inner periphery of said rim. 1

8. The pulperof claim 7 wherein said-cover is a flat, annular plate parallel with the axially outer surface of saidrim. I

9. The pulper of claim 8 wherein said cleaning vanes are substantially identical plates. 5

10. The pulper of claim 9 wherein said cleaning vane plates are parallelograms extending between said rim and said cover and inclined approximately 45 to the axis of said rotor and approximately 45 to the radius of said rotor and oriented to have outwardly trailing edges relative to the direction of rotation of said rotor.

l l. THe pulper of claim 1 wherein a cylinder extends around said central region, said spokes are axially oriented plates extending radially outward from said cylinder, and said rim is formed as an annular box supported by said spokes. v i

12. The pulper of claim 11 wherein said annular box is formed of radially inner and outer cylinders, an axially inner, annular plate supporting said ridged surface of said rotor, and an axially outer, annular plate.

13. The pulper of claim 12' including mixing vanes around the axially outer periphery of said rotor.

14. The pulper of claim 1 wherein said ridged surfaces are formed of a plurality of ridged sector plates clamped in place on said rotor and stator.

15. The pulper of claim 14 wherein said sector plates have generally radial grooves oriented to pump radially outwardly.

16. The pulper of claim 14 wherein said sector plates have potted bases.

17. The pulper of claim 14 wherein said rotor and stator have peripheral abutment surfaces for engaging the radially outer edges of said sector plates and a clamp ring to secure the radially inner edges of said sector plates in place.

18. The pulper of claim 17 wherein said rotor and stator have a cylindrical ridge for engaging the radially inner edge of said clamp ring.

19. The pulper of claim 18 wherein said inner and outer edges of said sector plates are dove-tailed, and said abutment surfaces and said clamp rings have corresponding dove-tails to hold said sector plates in place.

20. The pulper of claim 1 wherein said cleaner includes spaced-apart vanes and said spokes are plates extending radially and axially of said rotor.

21. The pulper of claim 20 wherein said cleaner includea a cover extending radially outward beyond the inner periphery of said rim and said cleaning vanes extend between said rim and said cover and are inclined approximately 45 to the axis of said rotor and approximately 45 to the radius of said rotor and oriented to have outwardly trailing edges relative to the rotational direction of said rotor.

22. The pulper of claim 21 wherein said cover is a flat, annular plate parallel with the axially outer surface of said rim, and said cleaning vanes are substantially identical plates formed as parallelograms.

23. The pulper of claim 20 wherein said spokes extend for an axial distance of at least 6 percent of the outside diameter of said rotor, and said cleaner and said ridged surface of said rotor are spaced axially on opposite sides of said spokes.

24. The pulper of claim 23 wherein said cleaner includes a cover extending radially outward beyond the inner periphery of said rim, and said cleaning vanes extend between s'aid'rim and said cover and are inclined approximately 45 to the axis of said rotor and'approximately 45 to the radius of said rotor and oriented to haveoutWardly trailing-edges relative to.th'e-rotational direction of said rotor. g i

25. The pulper of claim 24 wherein said cover is a flat annular plate parallel with the axially outer surface of said rim, and said cleaning vanes are substantially identical plates formed as parallelograms.

26. The pulperof claim 1 wherein a cylinder extends around said central region, said spokes are plates ex-' tending anxially ofsaid rotor and extending radially outward from said cylinder, said rim is formed as an annular box supported by said spokes, and said cleaner includes spaced-apart cleaning vanes.

27. The pulper of claim'2 6 wherein said annular box is formed of radially inner and outer cylinders, an axially inner, annular plate supporting said-ridged surface of said rotor, and an axially outer, annular plate.

28. The pulper of claim 27 wherein said'cleaner includes a cover extending radially outward beyond the inner periphery .of said rim, and said cleaning vanes extend between said rim and said cover and are inclined approximately 45 to the axis of said rotor and approximately 45 to the radiusof said rotor and oriented to have outwardly trailing edges relative to the rotational direction of said rotor.

29. The pulper of claim 28 wherein said cover is a flat, annular plate parallel with the axially outer surface of said rim, and said cleaning vanes are substantially identical plates formed as parallelograms.

30. The pulper of claim 1 wherein said cleaner includes spaced-apart vanes, said spokes are plates extending radially and axially of said rotor, and said ridged surfaces are formed of a plurality of ridged sector plates clamped in place on said rotor and stator.

31. The pulper of claim 30 wherein said sector plates have generally radial grooves oriented to pump outwardly, said rotor and stator have peripheral abutment surfaces to engage the radially outer edges of said sector plates, and a clamp ring secures the radially inner edges of said sector plates in place.

32. The pulper of claim 30 wherein said sector plates have potted bases.

33. The pulper of claim 32 wherein said sector plates have generally radial grooves oriented to pump outwardly, said rotor and stator have peripheral abutment surfaces to engage the radially outer edges of said sector plates, a clamp ring secures the radially inner edges of said sector plates in place, said rotor and stator have a cylindrical ridge engaging the radially inner edge of said clamp ring, said inner and outer edges of said sector plates are dove-tailed, and said abutment surfaces and said clamp rings have corresponding dove-tails to hold said sector plates in place.

34. The pulper of claim 30 wherein a cylinder extends around said central region, said spokes are axially oriented plates extending radially outward from said cylinder, and said rim is formed as an annular box supported by said spokes.

35. The pulper of claim 34 wherein said cleaner includes a cover extending radially outward beyond the inner periphery of said rim, and said cleaning vanes extend between said rim and said cover and are inclined approximately to the axis of said rotor and approximately 45 to the radius of said rotor and oriented to have outwardly trailing edges relative to the rotational direction of said rotor.

36. The pulper of claim 35 wherein said cover is a flat, annular plate parallel with the axially outer surface of said rim, and said cleaning vanes are substantially identical plates formed as parallelograms.

Claims

1. An improved pulper comprising: a. a stator having a ridged surface on a peripheral annular region; b. a rotor adjacent said stator; c. a shaft for driving said rotor; d. means for supporting the central region of said rotor on said shaft; e. said rotor having a peripheral rim; f. spokes supporting said rim on said central region to provide a substantially open, annular region radially inward from said rim; g. a ridged surface of said rim confronting said ridged surface of said stator; and h. a cleaner spaced over said open region.

4. The pulper of claim 2 wherein said cleaner and said ridged surface of said rotor are spaced axially on opposite sides of said spokes.

5. The pulper of claim 1 whErein said cleaner includes vanes.

6. The pulper of claim 5 wherein said vanes are inclined approximately 45* to the axis of said rotor and approximately 45* to the radius of said rotor and oriented to have outwardly trailing edges relative to the direction of rotation of said rotor.

7. The pulper of claim 5 wherein said cleaner includes a cover extending radially outward beyond the inner periphery of said rim.

8. The pulper of claim 7 wherein said cover is a flat, annular plate parallel with the axially outer surface of said rim.

9. The pulper of claim 8 wherein said cleaning vanes are substantially identical plates.

10. The pulper of claim 9 wherein said cleaning vane plates are parallelograms extending between said rim and said cover and inclined approximately 45* to the axis of said rotor and approximately 45* to the radius of said rotor and oriented to have outwardly trailing edges relative to the direction of rotation of said rotor.

11. THe pulper of claim 1 wherein a cylinder extends around said central region, said spokes are axially oriented plates extending radially outward from said cylinder, and said rim is formed as an annular box supported by said spokes.

13. The pulper of claim 12 including mixing vanes around the axially outer periphery of said rotor.

16. The pulper of claim 14 wherein said sector plates have potted bases.

21. The pulper of claim 20 wherein said cleaner includea a cover extending radially outward beyond the inner periphery of said rim and said cleaning vanes extend between said rim and said cover and are inclined approximately 45* to the axis of said rotor and approximately 45* to the radius of said rotor and oriented to have outwardly trailing edges relative to the rotational direction of said rotor.

24. The pulper of claim 23 wherein said cleaner includes a cover extending radially outward beyond the inner periphery of said rim, and said cleaning vanes extend between said rim and said cover and are inclined approximately 45* to the axis of said rotor and approximately 45* to the radius of said rotor and oriented to have outwardly trailing edges relative to the rotational direction of said rotor.

26. The pulper of claim 1 wherein a cylinder extends around said central region, said spokes are plates extending anxially of said rotor and extending radially outward from said cylinder, said rim is formed as an annular box supported by said spokes, and said cleaner includes spaced-apart cleaning vanes.

27. The pulper of claim 26 wherein said annular box is formed of radially inner and outer cylinders, an axially inner, annular plate supporting said ridged surface of said rotor, and an axially outer, annular plate.

28. The pulper of claim 27 wherein said cleaner includes a cover extending radially outward beyond the inner periphery of said rim, and said cleaning vanes extend between said rim and said cover and are inclined approximately 45* to the axis of said rotor and approximately 45* to the radius of said rotor and oriented to have outwardly trailing edges relative to the rotational direction of said rotor.

32. The pulper of claim 30 wherein said sector plates have potted bases.

35. The pulper of claim 34 wherein said cleaner includes a cover extending radially outward beyond the inner periphery of said rim, and said cleaning vanes extend between said rim and said cover and are inclined approximately 45* to the axis of said rotor and approximately 45* to the radius of said rotor and oriented to have outwardly trailing edges relative to the rotational direction of said rotor.