US3804340A

US3804340A - Method and apparatus for producing dry-defibrated cellulose

Info

Publication number: US3804340A
Application number: US00271101A
Authority: US
Inventors: K Ekman; N Blomqvist
Original assignee: Mo och Domsjo AB
Current assignee: FIBRE CONVERTING MACHINERY AB
Priority date: 1971-07-13
Filing date: 1972-07-12
Publication date: 1974-04-16
Anticipated expiration: 1991-04-16
Also published as: SE355613B; CH547393A; DE2233340A1; JPS5134482B1; DE2233340B2; GB1385402A; BE786158A; NL150867B; NL7209573A; DE2233340C3; IT965102B; FR2146073A5

Abstract

Method and apparatus are provided for producing dry disintegrated cellulose pulp such as cellulose fluff from bales of cellulose pulp in sheet form, by cutting the pulp sheets in the bale into strips while still located in the bale, and thereafter defibrating the strips, with an optional intermediate shredding step prior to defibrating.

Description

United States Patent 1191 Ekman et a].

METHOD AND APPARATUS FOR PRODUCING DRY-DEFIBRATED CELLULOSE inventors: Karl Ake Ekman, Harnosand; Nils Verner Blomqvist, Domsjoverken, both of Sweden Mo och Domsio AB, Ornskoldsvik, Sweden Filed: July 12, 1972 Appl. No.: 271,101

Assignee:

Foreign Application Priority Data July 13, 1971 Sweden 9076/71 us. (21.; 241/28, 241/29, 241/152 A,

Field of Search 241/28, 29, 152 R, 152 A; 1 l9/.56 83/394, 395, 467 A 14 1 Apr. 16, 1974 [56] 1 References Cited UNITED STATES PATENTS 282,052 7/1883 Christman 83/395 X 2,014,947 9/1935 McCulloch et a1. ..l l9/.56 X 3,406,916 10/1968 Lyon 1. 241/28 3,596,840 8/1971 Blomquist.... 241/28 3,692,246 9/1972 Law et a1. 241/28 Primary Examiner-Granville Y. Custer, Jr.

[5 7] ABSTRACT Method and apparatus are provided for producing dry disintegrated cellulose pulp such as cellulose fluff from bales of cellulose pulp in sheet form, by cutting the pulp sheets in the bale into strips while still located in the bale, and thereafter defibrating the strips, with an optional intermediate shredding step prior to defibrating.

'17 Claims, 4 Drawing Figures PATENTE APR] 6 m4 sum 1 0F 3 PATENTEDAPRIGIBM v 3' 04 340 SHEET 2 OF 3 METHOD AND APPARATUS FOR PRODUCING DRY-DEFIBRATED CELLULOSE The present .invention relates to a method and an apparatus for producing dry-disintegrated (fluffed) cellulose pulp from bales of cellulose pulp in sheet form. When practicing hitherto known methods for the aforementioned purpose, individual sheets of pulp are normally separated from the bale and then shredded into small pieces, which are later disintegrated. Known apparatus hitherto used for this purpose normally include a shredder, which breaks the pulp sheets down into coin-size pieces, and means for defibrating (fluffing) the shredded pulp. The shredder is normally in the form of a hammer mill. To avoid overheating of the shredder and also ignition of the pulp sheets during the shredding process, it is necessary to feed the sheets of pulp separately to the shredder. One serious disadvantage with this method of feeding the pulp to the shredder, is that the sheets of pulp often stick firmly together in the bale and can only be separated with great diffiwhy, or cannot be separated at all without disintegrating. The reason forthis is partly because the bales are heavily compressed during their manufacture and partly because, in the majority of cases, a pulp bale is handled very roughly during transport etc. and is subjected to impacts which cause the bale to become further compressed or deformed, owing to its soft consistency.

The aforementioned disadvantage is eliminated by means of the present invention. The invention relates to a method for producing dry-defibrated cellulose pulp (so-called fluff) from bales of cellulose pulp in sheet form and is mainly characterized by the fact that the pulp sheets are cut into strips while still located in the bale, after which the severed pulp strips are optionally shredded in a shredding device and the shredded pulp or pulp strips defibrated in a defibrating means.

The invention also relates to an apparatus for carrying out the method. The apparatus is characterized by a combination of means for cutting the pulp bales into strips, means for feeding thebales to the cutting means, and when desiredto a shredding means for shredding the pulp stripscutin the cutting means into smaller pieces, and means fordefibrating the pulp strips or the shredded pulp pieces.

Since the sheets of pulp are cut into strips before being shredded and/or defibrated and while they are still located in the bales, it is unnecessary for the pulp sheets to be removed separately from the bale and fed individually to the shredding means and the defibrating means. Thus, itis immaterial whether the sheets of pulp stick together in the bale or not, whereby the problem of separating the sheets one from the other is elimi nated.

The invention will now be described in more detail with reference to an embodiment of an apparatus constructed in accordance therewith and illustrated in the accompanying drawings, in which FIG. 1 is a side view of the apparatus according to the invention, comprising a cutting means, a shredding means and a defibrating means, the Figure also illustrating a consumer system for the defibrated cellulose pulps,

FIG. 2 illustrates the cutting means provided with knife means anda stop, seen from the shredding means,

FIG. 3 illustrates the cutting means with the knife means and stop during a downward movement when cutting strips from a bale of pulp sheets, and

FIG. 4 illustrates the cutting means with the knife means and stop in a lower turn or limit position.

In FIG. 1, the reference numeral 1 indicates a cutting means, 2 a shredding means and 3 a defibrating means. The cutting means 1 and the shredding means 2 are connected together by means of an obliquely upwardly extending belt conveyor 4 provided with guide edges, while the shredding means 2 is connected to the defibrating means 3 by means of a screw conveyor 5. The cutting means 1 comprises an endless belt conveyor 6, a knife means 7 having a downwardly directed cutting edge 8, a stop 9, a press 10 and a press table 11 arranged externally of the conveyor 6 in the conveying direction, the cutting edge 8 having a bevelled surface facing towards the stop 9. The knife means and the stop are fixedly mounted on a bracket structure 12 (FIG. 2) in vertically spaced relation, with the knife means being located mm above the stop. The knifemeans and the stop are spaced 30 mm apart horizontally. The bracket structure 12 with the knife means and the stop are arranged at the end of the press table 11 adjacent the conveyor 4 for movement between an upper and a lower turn or limit position. In the upper limit position, the bracket structure 12 is located with the upper edge of the stop 9 slightly above a bale 13 of pulp sheets located on the conveyor 6 and the press table 11 (FIG. I). When the bracket structure occupies its lower limit position, the edge of the knife means bears against a plastic member 14 let into the press table 11 and ex tending transversely across the whole width of the press table. The purpose of the plastic member 14 is to enable the knife means to cut throughthe lowermost sheet in a bale lying on the press table (as will be described hereinafter). The bracket structure 12 is connected to a drive mechanism (not shown), which drives the bracket structure between its limit positions. The press 10 is movably arranged adjacent the movement path of the knife means 7 and serves to urge a bale lying on the press table 11 against the press table, thereby to facilitate cutting of the knife means through the bale. The movement of the press and the movement of the bracket structure 12 are synchronized with each other in a manner such that the press holds the bale firmly pressed against the press table, with the exception of the time during which the whole of the knife means is located above the bale. A receiving bin 15 (FIG. 1) is arranged above the belt conveyor 4 at the input end of and immediately adjacent the movement path of the stop 9.

In the exemplified machine, the shredding means 2 comprises a hammer mill and the defibrating means 3 a disc refiner. The defibrating means is connected to a sheet feed roll and conveyor assembly 17 for manufacturing diapers. The shredding means 2, the defibrating means 3, the diaper manufacturing assembly 17 and the conveyors 4 and 5 are only illustrated diagrammatically in the Figure.

The illustrated apparatus operates in the following manner. Subsequent to moving the press 10 and the bracket structure 12 with the knife means 7 and stop 9 to the upper limit position, the shredding means 2, the defibrating means 3, the conveyors 4, 5 and-6 and the diaper manufacturing assembly 17 are set into operation. A number of bales 13 of pulp sheets are then supplied sequentially to the conveyor 6 at its in-feed end. The bales are successively moved by the conveyor in the direction of the arrow A (FlGS. l, 3 and 4) until the major portion of the first bale in the line is located on the press table 11, where it is stopped by the stop 9. The following bales are then stopped in sequence by the preceding bales, until the row of bales is at rest on the conveyor. Since the conveyor 6 is driven continuously, the bales are constantly held pressed against each other and the stop 9. The means driving the bracket structure 12 and the press are then started up, whereupon the press moves downwards into abutment with the bale lying on the press table 11 and presses the bale firmly against the press table. Immediately thereafter the knife means and the stop 9 move towards the lower limit position. During the downward movement of the knife means and the stop, the sheets of pulp in the bale clamped between the press 10 and the press table 11 are cut into strips (indicated at 18 in FIG. 3). In the lower limit position of the bracket structure 12, the cutting edge. of the knife means bears against the plastic member 14 in the press table 11, thereby ensuring that the lowermost sheet in the bale is properly cut by the knife means (FIG. 4). The width of the strips corresponds to the horizontal distance between the knife means and the stop. Since the vertical distance between the knife means and the stop is always constant and since the bevelled or chamfered surface of the knife edge is turned towards the stop, the pulp strips are thrown out between the knife means and the stop, down into the receiving bin 15 (FIG. 1) as they are cut by the knife means. The strips of pulp fall, via the receiving bin, down onto the belt conveyor 4, which transports the strips to the shredding means 2.

When the bracket structure 12 has reached its lower limit position, the knife means 7 has cut a strip of pulp from each sheet in the front bale. Thus, when a strip has been cut from the bale, the bale and similarly the remaining bales in the row of bales on the conveyor 6 is no longer supported by the stop 9, but lies instead against the rear side of the knife means 7, which together with the press 10 prevents the bales from moving in the feed direction. Immediately after the bracket structure 12 has reached the lower limit position, it turns and moves upwardly. During this upward movement, the knife means 7 slides with its rear side surface against the front bale. When the knife means has moved clear of the bale, the press 10 moves upwards, away from the bale. In this position there is nothing to prevent the bales from moving in the feed direction and the bales are therefore automatically moved by the continuously operating conveyor 6 until the front bale again bears against the'stop 9, whereupon movement of the bales ceases. The distance moved by the bales corresponds to the horizontal distance between the edge of the knife means and the rear side surface of the stop, i.e. the width of each strip cut from the bale. When the bales are again at rest, the press 10 again moves downwardly and presses the front bale against the press table 11. Immediately thereafter, the knife means 7 and the stop 9 move downwardly and the working sequence is repeated in the manner described above. No interruption or change in working sequence takes place during the change between the bales, but that the bales are constantly held firmly pressed against each other by the constantly operating conveyor 3. The strips of pulp are conveyed from the cutting means 1 to the shredding means 2 by the belt conveyor 4. Owing to the fact that the conveyor 4 is inclined obliquely upwardly, the interruption in the feed from the cutting means as a result of the inoperative return stroke of the knife means is eliminated to a certain extent during transport of the strips. The pulp strips are shredded in the shredding means 2 into coin-size pieces, which are then conveyed by the screw conveyor 5 to the defibrating means 3, where they are disintegrated between beating discs in a known manner. The defibrated pulp or fluff is discharged from the defibrating means 2 and passed to the diaper manufacturing assembly 17.

Although the invention has been described and illustrated with reference to an embodiment thereof, it will be understood that a number of modifications can be made within the purview of the invention. For example, it is not necessary for the movement path of the bracket structure 12 to be obliquely positioned in one plane, but that said movement path may also be fully vertical in all planes. However, by obliquely positioning the movement path as illustrated in the exemplary embodiment, a very good cutting action is obtained, since the knife means 7 not only cuts through the sheets but also effects a certain sawing action in one direction.

Neither is it necessary for the shredding means 2 to be in the form of a hammer mill, but that any suitable shredding means may be used. For example, the shredding means may be of the type which includes a rotatable roll provided with shredding members and an anvil suitably constructed for the roll.

The defibrating means 3 may also differ from the illustrated example and the disc refiner of the exemplary machine may suitably be replaced with a peg mill or hammer mill provided with grinding means for pulp defibrating purposes.

It is also possible within the purview of the invention to replace the conveyors between the cutting means, the shredding means and the defibrating means with other suitable conveying means than those used with the illustrated machines.

The knife means 7 and the stop 9 may also be arranged at other distances apart than those illustrated with the exemplary embodiment. The horizontal distance between the knife means and the stop, corresponding to the width of the cut strips, should, however, not be so great that the strips cannot be readily treated in subsequent machines.

The vertical distance between the knife means and the stop should be sufficient to enable the cut strips to be thrown therebetween unhindered. With one modification of the invention, the cutting means can be provided with means by which the horizontal and vertical distance between the knife means and the stop can be regulated, thereby enabling any desired strip width to be set on the machine. This enables the use of shredding means of greatly varying capacity and heat conductivity.

It is also possible to provide the cutting means with means by which the length of the movement of the knife means and the

stop

7, 9 can be adjusted to pulp bales of varying height.

It is also possible within the purview of the invention to defibrate the cut pulp strips directly without subjecting the same to a preceding shredding operation. A system suitable therefor thus includes all the aforementioned means described with reference to the illustrated embodiment of the invention, with the exception of the shredding means and its discharge conveyor. In order for the defibrating means to be able to expose the fibres in the pulp strips, it must comprise a hammer mill provided with a screen of suitable mesh.

We claim: 1. A method for producing dry-defibrated cellulose pulp from cellulose pulp sheet baled in parallel juxtaposed relationship, which comprises cutting the baled pulp sheets into strips and defibrating the pulp strips.

2. A method in accordance with claim 1, which comprises shredding the pulp strips prior to defibrating.

3. A method in accordance with claim 1, which comprises cutting off a first series of strips, one strip from each pulp sheet in the bale, in sequence, proceeding across the pulp sheets in the bale, from one side of the bale to the other, while holding the bale in a fixed position, then cutting off a second series of strips from each pulp sheet in the bale in like manner, and continuing until the entire bale has been cut into strips.

4. A method in accordance with claim 3, in which the cutting is crosswise of the bale.

5. A'method in accordance with claim 3, in which the cutting is lengthwise of the bale.

6. A method in accordance with claim 1 in which the bale is held under compression during the cutting.

7. An apparatus for producing dry defibrated cellulose pulp from bales of cellulose pulp sheet baledin parallel juxtaposed relationship, comprising, in combination, means for cutting off strips from the baled sheet pulp, proceeding across the pulp sheets in the bale, from one side of the bale to the other, and means for defibrating the cut strips.

8. An apparatus in accordance with claim 7, which includes means for shredding the pulp strips prior to defibrating. j

9. An apparatus'in accordance with claim 7, including means for feeding the pulp sheet bale to the cutting means, means for retaining the bale in a position for cutting strips of desired width, and means for feeding the cut pulp sheet strips to the defibrating means.

10. An apparatus in accordance with claim 7, including means for holding the bale under compression during the cutting.

11. An apparatus in accordance with claim 7, in

which the cutting means comprises a knife with a cutting edge extending across and facing the bale, and movable reciprocably from one side of the bale through the bale to the other side; and means reciprocably movable with the knife and spaced from the knife edge a distance equal to the width of the strip to be cut off, holding the bale in the spaced width position during the cutting.

12. An apparatus in accordance with claim 11, comprising means for feeding a pulp bale to the cutting means; stop means for-arresting movement of a pulp bale conveyed by the feed means in the feed direction when in a position for cutting; and retaining means holding the bale fixed in the cutting position relative to the knife to be cut thereby.

13. An apparatus in accordance with claim 12, comprising means for supporting a bale during the cutting, the retaining means holding the bale against the support means under compression.

14. An apparatus in accordance with claim 13, in which the support means comprises a supporting surface of a material softer than the cutting knife edge, and arranged to engage the knife edge and serve as a stop for the knife after the knife has cut through the last sheet of the bale in juxtaposition to the supporting surface.

15. An apparatus in accordance with claim 12, comprising drive means operatively synchronizing movement of the knife, bale feeding means, and baleretaining means so that whenever the knife is being reciprocatingly returned to its initial cutting position, after cutting the last pulp sheet in a pulp bale, the pulp bale feed means advances the next bale forward against the stop and the bale-retaining means engages and fixes that bale in a position to be cut by the next cutting movement of the knife.

16. An apparatus in accordance with claim 11, including means for adjusting the spacing between the knife and the bale holding means, so as to adjust the width of the strip cut off by the knife.

17. An apparatus in accordance with claim 11, including means for adjusting the span of reciprocating movement of the knife to correspond to the span of the bale being cut.

' UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,804,340 A Dated April 16, 1974 invento Karl Ake Ekman et a1 It is certified that error appears in the above-identified patent A and that said Letters Patent are hereby corrected as shown below:

F'column 1,Int he Title add the midi-PULP after 5! m t "CELLULOSE", so that thetitle w reads: METHOD AND APPARATUS FOR PRODUCING DRY DEFIBRATED CELLULOSE PULP Signed and ,gc alcd this twenty-third D ay or December I 9 75 [SEAL] A tlest:

RUTH C. MASON Arresting Officer C. MARSHALL DANN Commissioner ofParems and Trademarks

Claims

1. A method for producing dry-defibrated cellulose pulp from cellulose pulp sheet baled in parallel juxtaposed relationship, which comprises cutting the baled pulp sheets into strips and defibrating the pulp strips.

5. A method in accordance with claim 3, in which the cutting is lengthwise of the bale.

6. A method in accordance with clAim 1, in which the bale is held under compression during the cutting.

7. An apparatus for producing dry defibrated cellulose pulp from bales of cellulose pulp sheet baled in parallel juxtaposed relationship, comprising, in combination, means for cutting off strips from the baled sheet pulp, proceeding across the pulp sheets in the bale, from one side of the bale to the other, and means for defibrating the cut strips.

8. An apparatus in accordance with claim 7, which includes means for shredding the pulp strips prior to defibrating.

9. An apparatus in accordance with claim 7, including means for feeding the pulp sheet bale to the cutting means, means for retaining the bale in a position for cutting strips of desired width, and means for feeding the cut pulp sheet strips to the defibrating means.

11. An apparatus in accordance with claim 7, in which the cutting means comprises a knife with a cutting edge extending across and facing the bale, and movable reciprocably from one side of the bale through the bale to the other side; and means reciprocably movable with the knife and spaced from the knife edge a distance equal to the width of the strip to be cut off, holding the bale in the spaced width position during the cutting.

12. An apparatus in accordance with claim 11, comprising means for feeding a pulp bale to the cutting means; stop means for arresting movement of a pulp bale conveyed by the feed means in the feed direction when in a position for cutting; and retaining means holding the bale fixed in the cutting position relative to the knife to be cut thereby.

15. An apparatus in accordance with claim 12, comprising drive means operatively synchronizing movement of the knife, bale feeding means, and bale-retaining means so that whenever the knife is being reciprocatingly returned to its initial cutting position, after cutting the last pulp sheet in a pulp bale, the pulp bale feed means advances the next bale forward against the stop and the bale-retaining means engages and fixes that bale in a position to be cut by the next cutting movement of the knife.