US2860550A - Paper machinery - Google Patents

Description

' Nov. 18, 1958 D. L. STARK PAPER MACHINERY 2 Sheets-Sheet 1 Filed Sept. 28, 1956 .Q INVENTOR. f DONALD LOUIS STARK W wmfl ATTORNEYS "Nov. 18, 1958 Filed Sept. 28, 1956 D. L. STARK PAPER MACHINERY 2 Sheets-Sheet 2 ATTORNEYS United States Patent PAPER MACHINERY Donald Louis Stark, Appleton, Wis., assignor to The Black-Clawson Company, Hamilton, Ohio, a corporation of Ohio Application September 28, 1956, Serial No. 612,634 6 Claims. (Cl. 92-23) This invention relates to pulping apparatus for paper making stock and the like.

The invention has particular relation to pulping apparatus adapted for use in handling and repulping the damaged paper web commonly known as broke" resulting from a break in the newly formed paper web during operation of a paper machine. In addition, the invention is concerned with the practical difficulty in paper making operation that while there may be extended periods when the paper machine is operating properly and therefore during which pulping apparatus particularly intended for handling broke is standing by, when a break does occur, action is required immediately, and this is increasingly true in relation to the web speed of the machine. Thus with speeds as high as 2,000 to 3,000 feet per minute now considered practicable, a break lasting only a few minutes could produce a staggering accumulation of broke in the absence of efiicient means for disposing of the broke practically as rapidly as it is formed.

, It is accordingly important to provide for rapid and efiicient disposal of broke whenever it is formed, and the most practical course is to repulp it for reuse in order to reduce waste. Furthermore, the repulping should be effected as quickly and as close -to the location of the break as possible to minimize problems of conveying and especially to minimize the accumulation of .dirt' on the broke sheet, which could call for further cleaning operations. It is therefore desirable as a practical matter that the apparatus for handling broke be' of suflicient capacity to handle all the broke normally to be expected in an emergency, but at the same time the practical economics of paper machine operation dictate that the initial and operating costs of such apparatus be kept to a minimum.

Having the above outlined conditions in mind, it is a primary object of the present invention to provide pulping apparatus of improved and novel structural and operational characteristics which especially adapt the apparatus for use in the handling of broke from a paper machine by reason of its simple and economical construction, its high capacity and low operating costs, and especially its ability to receive broke at full machine width and speed and to repulp such material at a sufficiently high rate and efliciency to prevent possible accumulation thereof even after an extended web break.

Another object of the invention is to provide such pulping apparatus in the form of an elongated tub having cylindrically curved end portions and having rotary impellers mounted on vertical axes centrally of each of these end portions to produce twin vortical patterns in the two halves of the tub, and particularly to provide such apparatus wherein each of the impellers is surrounded by a perforate annular screen for effecting continuous removal of the pulped stock as soon as it is reduced to a sufficiently small particle size for passage through such.

screen.

It is also an object of the invention to provide a broke Patented Nov. 18, 1958 Additional objects and advantages of the invention will be apparent from the following description, the accom panying drawings and the appended claims.

In the drawings- Fig. 1 is a fragmentary view in perspective illustratinga portion of a paper machine equipped with a broke handling system constructed in accordance with the present invention;

Fig. 2 is a plan view of the pulping apparatus in the system of Fig. 1;

Fig. 3 is a view partly in elevation and partly in section on the line 33 of Fig. 2;

Fig. 4 is an enlarged fragmentary section on the line 4--4 of Fig. 2; and

Fig. 5 is a diagrammatic plan view of another pulping apparatus in accordance with the invention.

Referring to the drawings, which illustrate preferred embodiments of the present invention, Fig. 1 shows fragmentarily certain parts of a typical paper machine including the last dryers 10 and the first pair of calender stacks 11 and 12. The floor 13 below these parts of the paper machine is shown as provided with a plurality of slots 14 through which the leading end of the web may be directed after a web break causing the formation of broke as indicated at 15. floor 13, Fig. 1 shows a continuous conveyor 16 of the belt type which receives the broke web 15 from above and delivers it to pulping apparatus indicated generally at 20 and constructed in accordance with the present invention as shown in more detail in Figs. 2-4.

The pulper 20 includes a tub comprising a pair of cylindrically curved end portions 21 and 22 and a pair a; of straight side portions 23 and 24, and a bottom section 25 is secured to these side and end portions to complete the tub. The twoend portions 21 and 22 have their centers of curvature spaced from each other by a distance substantially greater than their common radius of curvature but slightly less than twice this radius to provide an oblong configuration for the tub as viewed from above. The supporting structure for the tub includes legs and cross beams which are shown as I- beams 26 and 27 respectively.

The pulper tub is provided with a pair of rotary impellers 31 and 32 mounted for rotation on vertical axes coaxially with the semi-cylindrical end portions of the tub respectively, and each of these impellers is provided with its own drive indicated generally at 33. These impellers 31 and 32 are shown as of identical construction, and each includes a generally circular plate or disk provided with a plurality of impeller vanes 34 and 35 ar ranged around the disk to create an outward propelling effect on the stock during rotation of the impeller.

Each of the impellers 31 and 32 is surrounded by an annular perforate screen identified generally as 41 and 42 respectively of frustoconical shape, and these screens are shown as composed of a plurality of sector-shaped screen plates extending at an angle between the walls of the tub and the ring members 43 and 44 which surround the re spective impellers. The screens 41 and 42 cooperate with the wall and bottom of the tub and the rings 43 and .44 to form annular chambers 45 and 46 surrounding the respective impellers, and "these chambers meet at the center of the tub as shown in Fig. 3 and receive from Below this section of the the interior of the tub the stock which hasrbeen pulped to a sufiiciently small particle size for passage through the perforate screen plates." A common discharge line for the, screen chambers 45 and 46 is indicated at 47 and may lead off in any desired direction to a station for regeiving and further refining the pulp stock from the tu As best seen in Fig. 2, the screens 41 and 42 are of substantially the same outer radius as the cylindrically curvedend portions of the tub except adjacent the lateral center line of the tub, in which area the two screens have aligned parallel edges 50 which are joined along the lateral central line of the tub. This arrangement is shown in detail in Fig. 4, which illustrates the aligned edges of the screens as secured together by welding to a small rod 51,- and Fig. 4 also illustrates the perforations 52 through the respective screen plates. These joined sections of the two screens directly overlie the common portion of the screen chambers 45 and 46.

This structure and arrangement of the two screens 1/ leaves areas along the central portions of the two sides of the tub which are not covered by the screens, and these areas are accordingly filled in by sections 55 of conically curved imperforate plates which in effect form continuations of the outline of the two screens. The rotation of the respective impellers in operation creates vortical patterns in the stock centered on the impeller axes and the screens, and these curved imperforate plate sections 55 aid in guiding the stock in the desired vortical patterns. Further guiding action is obtained by triangular baffle members 56 which extend upwardly along the centers of the tub side portions 23 and 24.

As shown in Fig. 1, the pulper is preferably positioned in such relation to the conveyor 16 or other means for guiding the web 15 of broke from the paper machine that the web is delivered thereto with the width of the web extending lengthwise of the pulper tub, and also the pulper should be selected initially with the tub of a length sufficiently greater than the width of the web to receive the latter freely therein from above without lateral folding. A pulper of these proportions constructed in accordance with the invention will have adequate capacity to reduce the broke output of the machine of comparable width to a particle size sutliciently small for discharge through the screens 41 and 42 at an adequately rapid rate to prevent accumulation.

The twin impellers and their respective vortical patterns are particularly effective for this work, since in addition to the individual actions of the impellers, the vortex created by each impeller aids in submerging light broke which otherwise would tend to lie on top of the Water, and also the vortical patterns of the separate rotors will tend to interfere across the lateral center of the tub with resulting increased relative shearing effective on the material being pulped. Furthermore, it is not necessary to operate both impellers except during a web break, since a single impeller will easily handle trim and like surplus material during normal operation, and the second impeller drive need be started only at the time of the web break, thus effecting additional economies.

As noted, the length of the tub should be correlated with the width of the web being made on the machine with which the pulper of the invention is used. For example, satisfactory results have been obtained with paper machines having a wire of the order of 250 to 260 inches in width with the tub approximately 12 feet wide and 23 feet long utilizing a pair of rotors each 66 inches in diameter. For materially smaller or larger paper machines, the size of the tub and rotors may be correspondingly changed. For machines of very great width, such as in excess of 300 inches, it may be desirable to utilize three rotors and a tub of the proportions and general construction illustrated in Fig. 5. g In such tub 60, the end sections including the rotors 61 and 62 are of essentially the same construction previously described' but are spaced sufficiently to receive a center section and rotor 63 therebetween, and the parts 65 and 66 correspond to the parts 55 and 56 respectively. In-this multiple rotor unit, it is practical to utilize somewhat smaller rotors, for example three rotors 48 inches or 54 inches in diameter in a tub 10 feet wide and approximately 28 feet long. This arrangement provides thoroughly adequate pulping capacity while maintaining the overall dimension of the tub within convenient limits, and all of the other advantages of the invention will also be present.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. Pulping apparatus of the character described for paper making stock especially adapted forreceiving broke webs of substantial width for repulping, comprising a tub having semi-cylindrical end portions spaced from each other by a distance greater than the radius thereof, straight side portions connecting said semi-cylindrical por-' tions of said tub, a bottom connected with said side and end portions of said tub, a pair of rotary impellers mounted in said tub on vertical axes coaxial with said semi-cylindrical end portions respectively, means forming an annular, perforate screen surrounding each of said impellers and cooperating with said tub bottom to define annular chambers for receiving stock from the interior of said tub of sufliciently small particle size for passage through said screens, drive means for rotating said impellers to create generally vortical patterns in the stock centered onsaid axes, and the distance between said axes being less than the diameter of said semi-cylindrical tub portions to cause said vortical stock patterns to interfere with each other in the central portion of said tub.

2. Pulping apparatus of the character described for paper making stock especially adapted for receiving broke webs of substantial width for repulping, comprising a tub having semi-cylindrical end portions spaced from each other by a distance greater than the radius thereof and less than the diameter thereof straight side portions connecting said semi-cylindrical portions of said tub, a bottom connected with said side and end portions of said tub, a pair of rotary impellers mounted in said tub on vertical axes coaxial with said semi-cylindrical end portions respectively, means forming an annular perforate screen surrounding each of said impellers and cooper ating with' said tub bottom to define annular chambers for receiving stock from the interior of said tub ofsufficiently small particle size for passage through said' screens, said screens being of substantially the same outer radius as said semi-cylindrical tub portions except in the portions thereof located adjacent the center of said tube to leave marginal areas bounded by said screens and said side portions of said tub, means in said marginal areas and on said side portions of said tub for directingthe stock in generally vortical patterns about the axes of said impellers respectively, and the distance between said axes being less than the diameter of said semi-cylindricaltub' portions to cause said vortical stock patterns to interfere with each other in'the central portion of said tub.

3. Pulping apparatus of the character described for paper making stock especially adapted for receiving broke webs of substantial width for rcpulping, comprising a tub having semi-cylindrical end portions spaced from each other by adistance greater than the radius thereof, straight side portions connecting said semi-cylindrical portions of said tub, a bottom connected with said side and end portions of said tub, a pair of rotary impellers mounted in said tub on vertical axes coaxial with said semi-cylindrical endv portions, respectively, means forming an annular perforate screen of generally frustoconical shape surrounding each. of said. impellers and cooperating with said tub bottom to define annular chambers for receiving stock from the interior of said tub of sufficiently small particle size for passage through said screens, said screens being of substantially the same outer radius as said semicylindrical tub portions except in the portions thereof located adjacent the center of said tub, said centrally located screen portions having aligned parallel edges joined together across the lateral center line of said tub, and means in the side portion of said tub adjacent said centrally located screen portions for directing the stock in generally vortical patterns about the axes of said impellers respectively.

4. Pulping apparatus of the character described for paper making stock especially adapted for receiving broke webs of substantial width for repulping, comprising a tub having semi-cylindrical end portions spaced from each other by a distance greater than the radius thereof, straight side portions connecting said semi-cylindrical portions of said tub, a bottom connected with said side and end portions of said tub, a pair of rotary impellers mounted in said tub on vertical axes coaxial with said semi-cylindrical endportions respectively, means forming an annular perforate screen of generally frustoconical shape surrounding each of said impellers and cooperating with said tub bottom to define annular chambers for receiving stock from the interior of said tub of sufliciently small particle size for passage through said screens, said screens being of substantially the same outer radius as said semi-cylindrical tub portions except in the portions thereof located adjacent the center of said tub to leave marginal areas bounded by said screens and said side portions of said tub, imperforate plate means forming conically curved continuations of said screens in the areas bounded by each said screen together with the adjacent said side wall and the lateral center line of said tub, and means forming a baffle extending upwardly along the center of each said side wall and above the adjacent said imperforate plate means for cooperation with said plate means to direct the stock in generally vortical patterns about the axes of said impellers respectively.

5. Pulping apparatus of the character described for use in conjunction with a paper machine to repulp broke webs of substantial width having means located in fixed relation with said paper machine for receiving a broke web therefrom and guiding said web along a predetermined path extending below said machine, comprising a tub having semi-cylindrical end portions spaced from each other by a distance providing an overall length of said tub greater than the width of said web, straight side portions connecting said end portions of said tub, a bottom connected with said side and end portions of said tub, means for mounting said tub in fixed relation below said paper machine and across said path of said broke web to receive the entire width of said web therein generally parallel with the length of said tub, a pair of rotary impellers mounted in said tub on vertical axes coaxial with said semi-cylindrical end portions respectively, drive means for rotating said impellers to effect pulping of said web into stock, and means forming an annular perforate screen surrounding each of said impellers and cooperating with said tub bottom to define annular chambers for receiving stock from the interior of said tub of sufliciently small particle size for passage through said screens. 6. Pulping apparatus of the character described for use in conjunction with a paper machine to repulp broke webs of substantial width having means including a conveyor located in fixed relation below said paper machine for receiving a broke web therefrom and guiding said web along a predetermined path, comprising a tub having semi-cylindrical end portions spaced from each other by a distance providing an overall length of said tub greater than the width of said web, straight side portions connecting said end portions of said tub, a bottom connected with said side and end portions of said tub, means for mounting said tub below said paper machine in fixed relation with said conveyor and across said path of said broke web to receive the entire width of said web therein generally parallel with the length of said tub, a pair of rotary impellers mounted in said tub on vertical axes coaxial with said semi-cylindrical end portions respectively, drive means for rotating said impellers to effect pulping of said web into stock, and means forming an annular perforate screen surrounding each of said impellers and cooperating with said tub bottom to define annular chambers for receiving stock from the interior of said tub of sufiiciently small particle size for passage through said screens.

References Cited in the file of this patent UNITED STATES PATENTS 2,289,612 Wells July 14, 1942 2,641,971 Ellis June 16, 1953 2,661,664 Baxter Dec. 8, 1953 2,667,106 Hyman et al Jan. 26, 1954 2,681,598 Baxter June 22, 1954 2,696,766 Stark Dec. 14, 1954 2,775,168 Baxter Dec. 25, 1956

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