US3519211A - Disintegration process for fibrous sheet material - Google Patents

Description

y W70 R. M. SAKULICH ETAL 3,519,211

DISINTEGRATION PROCESS FOR FIBROUS SHEET MATERIAL Filed May 26. 1967 2 Sheets-Sheet l INVENTORS Richard M. Sokulich BY Mario 8. Morson ATTORNEY .Fufiy 7, 1970 R. M. SAKULICH ET AL 3,519,211

DISINTEGRATION PROCESS FOR FIBROUS SHEET MATERIAL Filed May 196'? Sheets-Shoot .1:

INVENTORS Richard M. Sokulich BY Mono S. Morson ATTORNEY United States Patent 3,519,211 DISINTEGRATION PROCESS FOR FIBROUS SHEET MATERIAL Richard M. Sakulich, Cincinnati, and Mario S. Marsan,

Springfield Township, Hamilton County, Ohio, assignors to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio Filed May 26, 1967, Ser. No. 641,549 Int. Cl. 1302c 13/08 US. Cl. 241-18 Claims ABSTRACT OF THE DISCLOSURE A process for continuously converting dried cellulosic fibrous sheet material into a dispersion of individual fibers in air. The fibrous sheet is advanced into a disintegrating device wherein the end of the sheet is repeatedly impacted at a predetermined velocity by one or more impacting elements. The fibrous sheet is entirely disintegrated into individual fibers at relatively high rates.

This invention relates to the art of disintegrating fibrous sheet material. More particularly, it relates to a process whereby a dried cellulosic fibrous sheet is impacted under predetermined operating conditions to cause progressive disintegration of the sheet into individual fibers.

The disintegration of fibrous sheet material has been carried out heretofore in what is known in the art as hammer-mills. These mills are characterized by a plurality of blades or hammers which beat the sheet causing it to disintegrate into particles and clumps of fibers. The particles and clumps are delivered to a screen, or to a plate having inward projections, whereupon the ends of the blades or hammers grind and disintegrate the particles and clumps into a mass composed of individual fibers, small clusters of fibers and fines. Prior art procedures of this kind are characterized by low rates and by the fact that the sheet is not totally disintegrated into individual fibers because some clusters of fibers are produced which remain intact and since some of the material is ground into fines. No prior art process and apparatus devices are known which will totally disintegrate a fibrous sheet at high rates into individual fibers without the use of a grinding surface or medium.

The principal object of the present invention is to obviate the difficulties encountered with prior art devices.

Another object of the present invention is the pro vision of a process for disintegrating dried cellulosic fibrous sheet material into individual cellulose fibers in such a way as to minimize the number of cut fibers and undisintegrated clusters of fibers.

Still another object of the present invention is the provision of a disintegration process for fibrous sheet material which is many times greater in capacity and effici ency for a given size than previously known processes and apparatus of this kind.

Yet another object of the invention is the provision of .a process, as stated above, which is particularly economical to operate with an improvement in the quality of the fibrous material that is produced by the disintegration of the fibrous sheet.

The nature and substance of the invention can be briefly summarized as comprising a process for converting dried cellulosic fibrous sheet material into a dispersion of individual fibers in air. The fibrous sheet material is fed inwardly to a disintegrating device having a plurality of impacting elements. The fibrous sheet is advanced con tinuously such that its end is disintegrated by the impact of the tips of the impacting elements on the free end of the sheet. The sheet is advanced at a relatively constant 3,519,211 Patented July 7, 1970 rate between successive impacts. The fibers are freed from the cellulosic sheet whereupon they are dispersed in air and conducted away from the impact Zone of disintegration by way of unobstructed passageways so they can be collected for further processing.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter regarded as forming the present invention, it is believed the invention will be better understood from the following description taken in connection with the accompanying drawing in which:

FIG. 1 is a side elevation showing the overall arrangement of an apparatus that can be used in carrying out the process of the invention.

FIG. 2 is a side elevation taken on the line 2-2 of FIG. 1 showing the disintegration apparatus and the slot for receiving the fibrous sheet material.

FIG. 3 is a cross section taken through the disintegrator on the line 3-3 of FIG. 2.

FIG. 4 is a fragmentary perspective view showing the preferred configuration of the tip of the impacting element used in the disintegrator.

Referring now to the drawings, a preferred embodiment of the process will be described with particular reference to the disintegration of a dried cellulosic fibrous sheet. The invention is particularly useful in disintegrating woodfiber drylap material of the kind found in commerce. Such drylap sheets are typically between about and about 200 pounds/1000 ft. basis weight, and generally have a caliper of at least about .04 inch or greater. A drylap sheet of this type usually has a moisture content of about 10%, although it has been found that the method of the invention produces better results if the initial moisture content is as low as possible. In fact, a moisture content of about 1% was found toproduce best results, although moisture contents lower than about 1% have not been tried.

As used herein, the term dried cellulosic fibrous sheet describes any type of fibrous sheet material capable of disintegration by the process of the invention. On the other hand, a drylap sheet will be understood to mean a wood-fiber material of the above described characteristics to which the invention is preferably applied.

Referring now to FIG. 1, two rolls 11 and 12, respectively, of drylap sheet material are supported by a common base plate and stand 13, mounted on the foundation 14. Webs of sheet material 15 and 16 are withdrawn from the rolls 11 and 12, respectively, and advanced to the disintegrator 17.

A motive power source which may typically be an electric motor 18 is supported on the stand 13, as illustrated in FIG. 1. A chain drive 19 is provided and is driven by the motor 18 such that it continuously rotates the drive sprockets 20 and 21. An idler sprocket 22 is provided to adjust the tension in the chain 19.

As best illustrated in FIG. 3, the sheets 15 and 16 are fed radially into the disintegrator 17. For this purpose, a pair of metering infeed rolls 23, 24 are mounted on one side of the disintegrator 17, and a second pair of metering infeed rolls 25, 26 are mounted on the other side of the disintegrator 17.

Referring back now to FIG. 1, it will be noted that the drive sprocket 20 is mounted for rotation on a common shaft with the metering infeed roll 24. Similarly, the drive sprocket 21 is mounted on a common shaft with the metering infeed roll 26. Thus, on movement of the chain drive 19, the metering roll pairs 23, 24, and 25, 26 are driven to feed the sheets 15 and 16 radially into the disintegrator 17.

The disintegrator 17, as best illustrated in FIGS. 2 and 3, comprises a casing 27 having a cylindrical bore 28. The internal configuration of the casing 27 is not important to the practice of the invention and it will be understood that a cylindrical bore 28 is shown in the preferred embodiment only as a matter of convenience. A shaft 29 is journaled in the casing such that one end extends outside the casing to receive a pulley 30. The motor 18 continuously drives the shaft 29 by means of the pulley 30 from a drive pulley (not shown) mounted on the motor shaft.

The casing 27 is provided with slotted inlet openings 31 and 32 to receive the drylap sheet 15 and 16 from opposite sides. A relatively large discharge outlet 37 is provided in the bottom of the casing 27. An air inlet opening 37a is provided at the top of the casing to permit air to be forced into the casing at a slight positive pressure from a suitable blower (not shown) or the like, for the purpose of dispersing the individual fibers and conducting them to the outlet 37 without any buildup of fibers in the casing which would tend to choke the apparatus. Additional air inlets 37a can be provided as necessary to carry out the function of dispersing the fibers in a most effective manner.

A rotor 33 is keyed to the shaft 29 and is provided with a plurality of slots 34 extending radially outwardly. An impacting element 35 is secured in each of the slots 34. A small clearance is provided between the tips 3 6 of the elements 35 and the supports for the sheets 15 and 16 at the inner ends 31a and 32a, respectively, of the inlet openings 31 and 32. The inner ends 31a and 32a form sheet supports for the sheets 15 and 16, respectively.

With the above arrangement of the parts of the apparatus, successive elements 35 impact the ends of each sheet 15 and 16 as the rotor 33 is turned. The path of travel and the manner of supporting the elements 35 is not critical to the practice of the invention. The only necessary requirement is that the elements 35 are moved such that their tips 36 impact the sheets 15 and 16 with at least one force component normal or perpendicular to the free ends of the sheets as the tips move past the sheet supports 31a and 32a.

It has been found that the clearance between the tips 36 and the edge of the sheet supports 31a and 32a must be maintained in a range of from about a distance equal to the thickness of the sheet material 15 and 16 up to ten times the sheet thickness. Preferably, this clearance is held to a range of from about the thickness of the sheet to four times the sheet thickness. Ideally, the clearance between the tips and the sheet supports is held about equal to the sheet thickness. It has been found that if this clearance is somewhat less than the sheet thickness, the sheet material will be severely cut and ground and the fibers will be badly mutilated. On the other hand, as the clearance increases from the ideal, the rate of disintegration decreases slightly, and when it gets beyond ten times the sheet thickness, there is no appreciable disintegration as the free ends of the sheet material tend to flow around the interior bore of the casing and form an undesirable internal restriction which will break off in large chunks.

In practicing the process of the invention, it has been found that the sheets 15 and 16 are preferably fed into the disintegrator at a constant rate that does not exceed about .05 inch between the impact of successive elements 35. In addition, the impact on the free end of the sheet material is preferably controlled by turning the rotor such that the impact velocity of the tips 36 is at least about 6,000 feet per minute, although an impact speed of at least about 12,000 feet per minute is preferred. Ideally, about 14,000 feet per minute has been found to be a most desirable impact velocity. It is also desirable to limit the time between successive impacts by the tips 36 to a minimum of about 0.4 milliseconds so that the deflected end of each sheet can spring back between successive impacts.

The individual distintegrated fibers which have been disengaged from the sheets 15 and 16 are removed from 4 the impact zone whereupon they are dispersed and discharged from the casing 27 by air flow. The air flow is generated, at least in part, by rotation of the rotor, al-

though it can be supplemented significantly by forced air flow into the casing from the inlet 37a. The individual fibers are removed at the discharge outlet 37 from where they can be conducted to a suitable collecting device.

The practice of the present process and apparatus results in the production of individual fibers in essentially the same size as they are derived originally from the pulping process prior to the manufacture of the fibrous sheet material being disintegrated. Such individual fibers may typically be somewhat contorted and flattened cylinders of about 10-15 microns diameter and about 2,500 microns in length.

FIG. 4 illustrates the preferred design of the tip 36 of the impacting elements 35. It will be noted that a series of parallel slots 38 are cut in the element tip 36 such that a square saw tooth design results consisting of the teeth 39. Best results have been found with this design. The tip 36 can have other configurations in practicing the invention, although the aforesaid square saw tooth design is preferred. It is also preferred that the elements 35 be assembled in the rotor 33 such that successive elements 35 have their teeth 39 offset in order that alternating areas of the fibrous sheets 15 and 16 are impacted. As discussed heretofore, the elements 35 are rigidly secured to the rotor 33. This is not essential since, if desired, the elements 35 can be rotatably attached to the rotor or mounted in some other fashion so long as the other criti cal aspects of the invention are carried out.

While the present illustration of the invention describes the feeding of two sheets into the disintegrator, it will be understood, of course, that the invention can be practiced with the infeeding of one sheet or three or more sheets. The only structural changes that would be needed under such varying circumstances are in the number of pairs of infeed rolls and the provision of corresponding openings in the disintegrator casing for receiving the sheet material.

Heretofore the invention has been described in terms of feeding the sheet material radially into the disintegrator casing. This is the preferred manner of sheet feeding. It is to be understood that radial feeding is not essential to the practice of the invention as the sheet material can be fed obliquely into the casing or it can even be fed axiallyinto the casing so that the side edges of the impacting elements cause disintegration. -It is only essential that the sheet be fed into the disintegrator such that the clearance from the tip of the impacting elements to the sheet support is Within the limits heretofore described and that the impact velocity of the impacting elements be maintained at the prescribed speeds.

While particular embodiments of the invention have been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention and it is intended to cover in the appended claims all such changes and modifications that are Within the scope of this invention.

What is claimed as new is:

1. A process for disintegrating dried cellulosic fibrous sheet material comprising the steps of feeding a fibrous sheet into a disintegrator, supporting said sheet in a slotted opening terminating in a sheet support in the casing of said disintegrator, moving a plurality of impacting elements having tips such that the tips move at a velocity of at least about 6,000 feet per minute, and impacting said tips against the end of the fibrous sheet so that impact is substantially normal to the plane of'the sheet whereby said fibrous sheet is disintegrated into individual fibers.

2. A process for disintegrating dried cellulosic fibrous sheet material as claimed in claim 1 including the step of moving the tips of said impacting elements past the sheet at a distance from the end of the sheet support at least about equal to the thickness of the sheet, but not greater than ten times the thickness of the sheet.

3. A process for disintegrating dried cellulosic fibrous sheet material as claimed in claim 2 including the step of feeding the sheet substantially radially into said disintegrator at a rate not exceeding about .05" between the impact of the tips of successive impacting elements.

4. A process for disintegrating dried cellulosic fibrous sheet material as claimed in claim 3 including the step of removing the individual disintegrated fibers by air flow to an unobstructed passageway.

5. A process for disintegrating dried cellulosic fibrous sheet material comprising the steps of feeding a fibrous sheet substantially radially into a disintegrator, supporting said sheet in a slotted opening terminating in a sheet support in the casing of said disintegrator, moving a plurality of radially mounted impacting elements having tips, impacting the tips against the end of the fibrous sheet substantially normal to the plane of the sheet at a velocity of at least about 12,000 feet per minute, and providing a clearance between the tips of said impacting elements and sheet support at least about equal to the thickness of the sheet but not greater than four times the thickness of the sheet whereby said fibrous sheet is disintegrated into individual fibers.

References Cited UNITED STATES PATENTS ROBERT C. RIORDON, Primary Examiner D. G. KELLY, Assistant Examiner US. Cl. X.R. 241-27, 28

Images