JP2016151068A - Basket for papermaking raw material screen device and screen system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a basket for screen, which can maintain a quality of paper that is finally obtained without enlarging a screen device and is hard to be clogged.SOLUTION: A basket 20 is a cylindrical basket for screen and is installed in a storage tank of a screen device. The basket 20 comprises a member including a front step part 21, which is located on a papermaking raw material inlet side, and a rear step part 22, which is located on a papermaking raw material outlet side. Multiple slits 21a, through which the papermaking raw material passes, are formed on a peripheral side of either the front step part 21 or the rear step side 22 so as to extend in central axis direction of the basket. Multiple round holes 22a, through which the papermaking raw material passes, are formed on the peripheral side of either the front step part 21 or the rear step part 22.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a basket provided in a screen device for papermaking materials. The present invention also relates to a screen system in which a plurality of screen devices are connected in a cascade manner.

  In general, paper is manufactured from pulp raw materials such as wood fiber. In the paper manufacturing process, various chemicals such as fillers, sizing agents, paper strength enhancers, and retention agents are added to pulp raw materials obtained from wood chips and waste paper as needed to prepare papermaking raw materials. . Also, the prepared papermaking material is carefully selected by a screen device to remove foreign matter, and the selected papermaking material is supplied to the headbox of the paper machine. The papermaking raw material introduced into the papermaking machine is jetted from the head box, dehydrated at the wire part to become wet paper, and after being squeezed by the press part, it is dried at the dryer part to become paper.

  As a screen device for selecting papermaking materials, for example, a rotary type is widely used. The rotary screen device has a storage tank for storing papermaking raw materials. A cylindrical screen basket is provided inside the storage tank, and a stirring member having rotating blades is provided inside the basket. It has a structure that is installed with an interval of. A circular round hole or a vertically long slit is formed on the peripheral side of the basket, and the basket permeates high-quality paper-making material with fibers, and impairs paper quality such as fiber lump and dust. It does not allow the passage of possible foreign objects. For this reason, by rotating the stirring member at high speed inside the basket and generating a water flow in the storage tank, only high-quality and carefully selected paper-making materials pass through the basket and are led to the outlet. On the other hand, the papermaking material containing foreign substances cannot pass through the basket, but is directly carried on the water stream and discharged from the outlet.

  As a rotary screen device, for example, the one disclosed in Patent Document 1 is known. The screen device of Patent Document 1 includes a storage tank in which a stirring member is installed and a basket in two stages. Then, after the first selection by the first storage tank and basket, the papermaking raw material that has passed the first selection is introduced into the second storage tank, and the second selection is performed by the second basket. In the device of Patent Document 1, a plurality of circular holes having a relatively large width are formed in the front basket, and a vertically long slit having a relatively small width is formed in the rear basket. The shape of the hole through which the papermaking raw material passes is different between the front stage and the rear stage. As described above, the apparatus of Patent Document 1 can select the papermaking raw material in double or triple so that the decomposition of coarse fibers can be promoted, foreign matters can be completely removed, and the papermaking raw material can be uniformly dispersed. Has been.

Japanese Patent Laid-Open No. 50-52306

  As described above, as the shape of the hole formed in the peripheral side portion of the basket, a circular round hole or a vertically long slit is generally known. In general, a round hole is formed wider in width (diameter) than a slit. For this reason, baskets with round holes are easy to pass through papermaking materials and are less likely to clog, but have a high possibility of passing foreign matter, so the quality of the final paper is maintained well. It is difficult to do. On the other hand, a basket formed with slits is less likely to allow foreign materials to pass through and can improve the quality of paper, but has the property that papermaking raw materials are difficult to pass and clogging is likely to occur. In this way, baskets with round holes and slits have demerits that the paper quality is impaired or clogged, and these demerits are absent or suppressed. The basket that was made has not existed before.

  In addition, in order to compensate for the properties of the round hole and the slit, the papermaking raw materials are first selected by a basket in which round holes are formed, and then selected by a basket in which slits are formed, as in Patent Document 1 above. For example, repeated selection may be considered. However, such double or triple baskets and storage tanks increase the overall size of the screen device, increasing the introduction and maintenance costs, and increasing the yield of paper production from papermaking raw materials. There was a problem of lowering. Further, in the apparatus of Patent Document 1, since the papermaking raw material is always carefully selected by a basket in which slits are formed, there is a possibility that clogging will eventually occur in the slits.

  Therefore, an object of the present invention is to provide a basket for a screen that can maintain the quality of the finally obtained paper without increasing the size of the screen device and that is less likely to cause clogging.

  The inventors of the present invention have intensively studied the means for solving the above problems, and as a result, divided one screen basket into a front-stage part on the inlet side and a rear-stage part on the discharge port side. A plurality of slits were formed on either one and a round hole was formed on the other. In this way, by forming both slits and round holes in one basket, it is possible to maintain the quality of the paper and prevent clogging without increasing the size of the screen device. Then, the present inventors have conceived that the problems of the prior art can be solved based on the above knowledge, and have completed the present invention. More specifically, the present invention has the following configuration.

The first aspect of the present invention relates to a screen basket 20 provided in the screen device 10.
The screen device 10 introduces the papermaking raw material from the inlet 11, selects the introduced papermaking raw material in the storage tank 13 in which the stirring member 12 is installed, guides the selected papermaking raw material from the outlet 14, and removes foreign matter. The papermaking raw material containing is discharged from the discharge port 15.
The basket 20 is a cylindrical member and is installed in the storage tank 13 of the screen device 10, and the stirring member 12 is provided therein (internally provided).
The basket 20 includes a member including a front stage portion 21 located on the inlet 11 side of the screen device 10 and a rear stage portion 22 located on the discharge port 15 side.
A plurality of slits 21a through which the papermaking material passes are formed in a shape extending in the central axis direction (FIG. 3: Y-axis direction) of the basket 20 on one peripheral side portion of the front stage portion 21 and the rear stage portion 22. Further, a plurality of round holes 22a through which the papermaking raw material passes are formed on the other peripheral side portion of the front stage portion 21 and the rear stage portion 22.

  As described above, the basket 20 of the present invention has both the slits 21a and the round holes 22a formed on the peripheral side thereof. If only the slits 21a are formed on the peripheral side portion of the basket 20, the collection accuracy of the foreign matter is improved, but the papermaking raw material is likely to be clogged. On the other hand, if only the round hole 22a is formed in the peripheral side portion of the basket 20, the papermaking raw material easily passes through and does not easily clog, but the possibility of foreign matters remaining on the paper increases. Therefore, as in the present invention, by making the basket 20 integrated with the portion where the slit 21a is formed and the portion where the round hole 22a is formed, the advantages and disadvantages of the slit 21a and the round hole 22a can be complemented. it can. Thereby, the basket 20 of the present invention makes it difficult for the papermaking raw material to be clogged, and can maintain the quality of the finally obtained paper. In addition, according to the present invention, the advantage of both the slit 21a and the round hole 22a can be enjoyed by one basket 20, so that the configuration of the apparatus can be made compact.

  In the basket 20 of the present invention, it is preferable that the slit 21 a is formed in the peripheral side portion of the front stage portion 21, and the round hole 22 a is formed in the peripheral side portion of the rear stage portion 22.

  As in the above configuration, the papermaking raw material first passes through the front part 21 where the slits 21a are formed, and then passes through the rear part 22 where the round holes 22a are formed. Thus, by providing the round hole 22a on the downstream side of the slit 21a, it is possible to prevent the papermaking raw material from forcibly flowing into the slit 21a, so that clogging generated in the slit 21a can be prevented. Further, by strictly selecting papermaking raw materials by using the slits 21a, the possibility of foreign matters entering the paper is reduced, so that the quality of the paper can be improved. Further, even if the papermaking material is essentially a large lump that cannot pass through the slit 21a or the round hole 22a, by providing the slit 21a on the front side of the basket 20, the lump of the papermaking material can be solved by the slit 21a. After being crushed, it passes through the round hole 22a. From this point, it can contribute to the improvement of paper quality.

  In the basket 20 of the present invention, the papermaking raw material in the storage tank 13 is preferably selected by passing through one of the slit 21 a and the round hole 22 a and led out from the outlet 14.

  As described above, clogging of the basket 20 can be prevented by carefully selecting the papermaking raw material by passing only one of the slit 21a and the round hole 22a. That is, as in Patent Document 1, there is a problem that clogging is particularly likely to occur in a slit in an apparatus that performs selection by always passing both a basket having a round hole and a basket having a slit. On the other hand, the configuration of the present invention can solve the problems of the prior art.

  The basket 20 of the present invention is composed of a member having an intermediate portion 23 interposed between a front stage portion 21 and a rear stage portion 22, and the intermediate portion 23 includes the entire circumferential direction of the basket 20 (FIG. 3: X-axis direction). It is preferable that neither the slit 21a nor the round hole 22a exists.

  As in the above configuration, a flat intermediate portion 23 is provided between the front stage portion 21 in which the slit 21a is formed and the rear stage portion 22 in which the round hole 22a is formed. Thereby, it is possible to prevent the foreign matter bounced without passing through the slit 21a from passing through the round hole 22a as it is. In other words, the presence of the flat intermediate portion 23 between the slit 21a and the round hole 22a allows the foreign matter that could not pass through the slit 21a to leave the inner surface of the basket 20 once, and in the water flow near the center of the basket 20. Returning to FIG. 2, after being crushed by the water flow, it passes through the round hole 22a. In this way, the slit 21a and the round hole 22a are clearly separated by the intermediate portion 23, so that even a foreign substance that cannot pass through the slit 21a is crushed by the water flow and returned to normal fibers. It can be expected to pass through the round hole 22a. Therefore, it leads to improvement of paper quality.

  In the basket 20 of the present invention, on the inner surface of the peripheral side portion of the front portion 21, a plurality of front step groove portions 21 b extending in the central axis direction are formed in the circumferential direction. , Slits 21a or round holes 22a are preferably formed.

  As described above, by forming the front groove portion 21b on the inner surface of the peripheral side portion of the front portion 21, turbulent flow can be generated near the inner surface. In order to disperse the papermaking raw material efficiently, the turbulent flow generated near the inner surface can crush, for example, foreign matters formed by the solidification of the papermaking raw material fibers.

  In the basket 20 of the present invention, a plurality of rear groove portions 22b extending in the central axis direction are formed on the inner surface of the peripheral side portion of the rear portion 22 in the circumferential direction, and the rear groove portion 22b has a plurality of rows. , Slits 21a or round holes 22a are preferably formed.

  By forming the rear groove portion 22b on the inner surface of the peripheral side portion of the rear stage portion 22 as in the above configuration, turbulence can be generated near the inner surface.

The second aspect of the present invention relates to a screen system in which a plurality of screen devices are connected. Each screen device carefully selects the papermaking raw material introduced from the inlet, extracts the selected papermaking raw material from the outlet, and discharges the papermaking raw material containing foreign substances from the outlet.
In the screen system 100 of the present invention, the outlet of the upstream screen device is connected to the inlet of the downstream screen device, and the outlet of the downstream screen device is the inlet of one of the upstream screen devices. It is configured in a cascade connection method connected to.
Here, at least the downstream screen device agitates the papermaking raw material in the storage tank 13 for storing the papermaking raw material introduced into the inlet 11 into which the papermaking raw material is introduced, the inlet 11. A stirring member 12, a cylindrical basket 20 for selecting a papermaking raw material installed in the storage tank 13 and having the stirring member 12 installed therein, an outlet 14 for deriving the papermaking raw material selected by the basket 20, a basket And a discharge port 15 for discharging papermaking raw materials containing foreign substances that are not carefully selected by 20.
Further, the basket of the screen device on the downstream side includes a member including a front stage portion 21 located on the inlet 11 side and a rear stage portion 22 located on the discharge port 15 side.
Here, a plurality of slits 21 a through which the papermaking raw material passes are formed in a shape extending in the direction of the central axis of the basket 20 on the peripheral side portion of either the front stage portion 21 or the rear stage portion 22. Further, a plurality of round holes 22a through which the papermaking raw material passes are formed on the other peripheral side portion of the front stage portion 21 and the rear stage portion 22.

  In the screen system according to the second aspect, basically, the basket 20 according to the first aspect described above is applied to a screen apparatus located on the downstream side among a plurality of screen apparatuses connected in cascade. It has a configuration. In the cascade method, the papermaking material discharged as containing foreign substances in the upstream screen device is carefully selected in the downstream screen device, and the papermaking material selected as normal in this downstream screen device is again selected. Installed in upstream screen device. Here, as described above, the basket 20 according to the first side surface is less likely to be clogged, has a high foreign substance removal accuracy, and can maintain the quality of the finally obtained paper. For this reason, by using the basket 20 according to the first side surface for the downstream screen device, it is possible to prevent clogging in the upstream screen device. Therefore, like the screen system according to the second aspect, it is preferable to use the basket 20 according to the first aspect of the present invention for the downstream screen device.

  According to the present invention, it is possible to provide a screen basket that can maintain the quality of the paper finally obtained without increasing the size of the screen device and is less likely to cause clogging.

FIG. 1 is a cross-sectional view showing an example of the overall structure of the screen device. FIG. 2 is a perspective view schematically showing the entire structure of the screen basket. FIG. 3 is a schematic side view showing the inner surface of the screen basket, and also shows a cross-sectional view of the portion indicated by each symbol. FIG. 4 is a block diagram schematically showing an example of the configuration of the screen system.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. This invention is not limited to the form demonstrated below, The thing suitably changed in the range obvious to those skilled in the art from the following forms is also included.
In this specification, “A to B” means “A to B”.

  FIG. 1 is a cross-sectional view showing an example of the overall structure of the screen device 10. In the present invention, the configuration of the screen device 10 is not particularly limited, and a known configuration can be adopted. In the example shown in FIG. 1, the screen device 10 includes a storage tank 13 for storing a papermaking raw material to be subjected to a selection process. The storage tank 13 is connected to the inlet 11, the outlet 14, and the outlet 15. The inlet 11 is a part into which a papermaking raw material to be subjected to a selection process is introduced. The outlet 14 is a part from which a selected high-quality papermaking raw material is derived. The discharge port 15 is a portion where papermaking raw materials including foreign matters after the selection process are discharged.

  Further, as shown in FIG. 1, a screen basket 20 is installed inside the storage tank 13. The basket 20 is a cylindrical member, and a plurality of holes for selecting papermaking raw materials are formed in the peripheral side portion thereof. For this reason, the papermaking raw material that has passed through the hole of the basket 20 is led to the outlet 14 as being of a good quality that does not contain foreign matter, and the papermaking raw material that does not pass through the hole of the basket 20 is assumed to contain foreign matter and the outlet 15 Led to. As shown in FIG. 1, by installing the basket 20, the storage tank 13 is partitioned into a primary chamber 13a and a secondary chamber 13b with the basket 20 as a boundary. The primary chamber 13 a is a region where the papermaking material introduced from the inlet 11 is agitated, and there is a papermaking material that cannot pass through the basket 20. The primary chamber 13 a of the storage tank 13 is connected to the inlet 11 and the discharge port 15, and the papermaking raw material that cannot pass through the basket 20 goes from the inlet 11 to the discharge port 15 through the primary chamber 13 a. On the other hand, the secondary chamber 13b is an area where the papermaking raw material that has passed through the basket 20 is present. The secondary chamber 13b of the storage tank 13 is connected to the outlet 14, and the papermaking raw material that has passed through the basket 20 goes to the outlet 14 through the secondary chamber 13b. As the basket 20, it is preferable to use a metal made of a metal that hardly rusts, such as stainless steel.

  A stirring member 12 is installed inside the basket 20. The stirring member 12 has a structure having a plurality of blade portions, and the blade portions are arranged with a predetermined distance from the inner surface of the peripheral side portion of the basket 20. The stirring member 12 rotates at a high speed in a certain direction inside the basket 20 and generates a water flow inside the storage tank 13. The papermaking raw material introduced from the inlet 11 is carefully selected by the basket 20 in accordance with the water flow generated by the stirring member 12 and is separated into one directed to the outlet 14 and one directed to the outlet 15.

  Further, the screen device 10 includes a rotation mechanism 16 that rotates the stirring member 12 in the storage tank 13. The rotating mechanism 16 includes, for example, a motor (not shown), a rotating portion 16a connected to the stirring member 12, and a belt portion 16b that transmits the rotation of the motor to the rotating portion 16a. As the motor rotates, the rotating portion 16a rotates via the belt portion 16b, and the rotational force is transmitted to the stirring member 12. However, the rotation mechanism 16 is not limited to such a configuration, and a known configuration can be adopted as appropriate.

  FIG. 2 schematically shows the configuration of the basket 20 installed in the storage tank 13 of the screen device 10. As shown in FIG. 2, the peripheral side portion of the basket 20 is basically constituted by one cylindrical member including a front stage portion 21 located on the inlet side and a rear stage portion 22 located on the discharge port side. Has been. In the embodiment shown in FIG. 2, an intermediate portion 23 is provided between the front portion 21 and the rear portion 22 in the peripheral side portion of the basket 20.

  In the embodiment shown in FIG. 2, a plurality of slits 21 a are formed in the front portion 21 of the basket 20. The slit 21 a is a linear through hole extending along the central axis direction of the basket 20. The slit 21a is formed in, for example, a rectangular shape whose longitudinal direction is the central axis direction. The slits 21 a are arranged in a plurality of rows at regular intervals in the circumferential direction of the basket 20. In addition, although illustration is abbreviate | omitted, the slit 21a may be arrange | positioned intermittently in the center axis direction of the basket 20 at fixed intervals.

  In the embodiment shown in FIG. 2, a plurality of round holes 22 a are formed in the rear stage portion 22 of the basket 20. The round hole 22a is a circular or elliptical through hole. The lateral width (diameter) of the round hole 22a is basically wider than the lateral width of the slit 21a. In addition, the round holes 22a are arranged in a row at regular intervals in the central axis direction of the basket 20, and the rows of the round holes 22a are arranged at regular intervals in the circumferential direction of the basket 20. Multiple rows are arranged. Further, the plurality of round holes 22a are arranged in a so-called staggered pattern. In other words, the round holes 22a belonging to a certain row are arranged (offset) by a predetermined interval in the central axis direction with respect to the round holes 22a belonging to a row adjacent thereto.

  Since the slit 21a formed in the peripheral side portion of the basket 20 has a narrower width than the round hole 22a, there is a low possibility that foreign substances contained in the papermaking raw material will pass through. For this reason, as in the present embodiment, the slits 21a are formed in the front portion 21 of the basket 20 where the papermaking raw material is first introduced, so that the foreign matters contained in the papermaking raw material are more strictly excluded. be able to. However, since the slit 21a has a narrow width, the fibers of the papermaking raw material are likely to be clogged. Therefore, in the present embodiment, a plurality of round holes 22 a are formed in the rear portion 22 of the peripheral side portion of the basket 20. The round hole 22a has a wider width (diameter) than the slit 21a, so that fibers of the papermaking raw material can easily pass therethrough. For this reason, the peripheral portion of the basket 20 is likely to be clogged with the slit 21a by providing the rear portion 22 with the round hole 22a together with the front portion 21 with the slit 21a. The papermaking raw material flows into the round hole 22a. Therefore, by simultaneously providing the slit 21a and the round hole 22a, it is possible to eliminate clogging of the papermaking material generated in the slit 21a. On the other hand, since the round hole 22a easily allows the papermaking raw material to pass through, there is a possibility that foreign matter may pass through with the papermaking raw material. With respect to this point, as in the basket 20 of the present embodiment, first, the selection is performed strictly by the slit 21a provided on the entrance side, thereby reducing the possibility of foreign matter being mixed. Further, when a foreign substance such as a lump of fibers is first brought into contact with the slit 21a near the entrance, the fibers may be unwound and changed to a normal papermaking material. For this reason, it is advantageous to form the slit 21a in the front part 21 near the entrance. In the present embodiment, the front portion 21 does not have the round hole 22a, and the rear portion 22 does not have the slit 21a. In this way, the front part 21 and the rear part 22 clearly distinguish the shape of the hole for performing selection.

  As shown in FIG. 2, a flat intermediate portion 23 is interposed between the front portion 21 and the rear portion 22 on the peripheral side portion of the basket 20. In the intermediate portion 23, neither the slit 21 a nor the round hole 22 a exists over the entire circumferential direction of the basket 20. Due to the presence of the flat intermediate portion 23 between the slit 21a and the round hole 22a, the foreign matter that could not pass through the slit 21a once separated from the inner surface of the basket 20 and returned to the water flow near the center of the basket 20. , After passing through the round hole 22a after being crushed by water flow. In this way, the slit 21a and the round hole 22a are clearly separated by the intermediate portion 23, so that even a foreign substance that cannot pass through the slit 21a is crushed by the water flow and returned to normal fibers, and finally round. It can be expected to pass through the hole 22a. The vertical width of the intermediate portion 23 (the length in the central axis direction of the basket) is, for example, preferably 10 mm or more or 15 mm or more, and preferably 20 mm to 100 mm, or 30 mm to 50 mm.

  FIG. 3 is a more detailed explanatory drawing of the structure of the basket 20, and shows a side view showing the inner surface of the basket 20 and a cross-sectional view of a portion indicated by various symbols. In FIG. 3, the patterns of the slits 21a and the round holes 22a are drawn only on a part of the peripheral side portion of the basket 20, but these patterns are originally formed over the entire peripheral side portion. Yes.

  In FIG. 3, the horizontal width of the slit 21a is indicated by a symbol W1, and the horizontal width (diameter) of the round hole 22a is indicated by a symbol W2. The lateral width W1 of the slit 21a is less than the lateral width W2 of the round hole 22a (W1 <W2). For example, the lateral width W1 of the slit 21a is preferably 1% to 50%, 5% to 40%, or 10% to 30%, where the lateral width W2 of the round hole 22a is 100%. Specifically, the lateral width W1 of the slit 21a is preferably 0.1 mm to 1.5 mm, or 0.15 mm to 1.0 mm. On the other hand, the lateral width W2 of the round hole 22a is preferably 1.0 mm to 2.5 mm, or 1.5 mm to 2.0 mm (W1 <W2).

  Further, as shown in the DD arrow sectional view and the EE arrow sectional view of FIG. 3, a plurality of front groove portions 21 b are formed on the inner surface of the front portion 21 of the basket 20. The front groove portion 21b is a groove-shaped portion that does not penetrate the basket 20 in the thickness direction. As shown in FIG. 3, each front groove portion 21 b has a linear shape extending in the central axis direction of the basket 20. The front groove portions 21b are arranged in a plurality of rows in the circumferential direction of the basket 20, and gaps with a predetermined interval are formed between the front groove portions 21b. Further, a slit 21a is formed in each front groove portion 21b. In the present embodiment, the number of slits 21a formed in each front groove portion 21b is one. However, a plurality of slits 21a can be formed in each front groove portion 21b. The length and width of each front-stage groove portion 21b are larger than the length and width of the slit 21a. Therefore, the front-stage groove portion 21b is formed so as to surround the slit 21a. Thus, by forming the front-stage groove portion 21b around the slit 21a, a turbulent flow of the papermaking raw material can be generated in the vicinity of the slit 21a. For this reason, even if a fiber lump is generated in the papermaking raw material, it is possible to pulverize the fiber lump by the turbulent flow generated in the vicinity of the slit 21a and return it to a normal state. is there. Therefore, it is possible to prevent the foreign matter from clogging the slit 21a and the foreign matter from passing through the slit 21a.

  Further, as shown in the FF arrow sectional view and the GG arrow sectional view of FIG. 3, a plurality of rear groove portions 22 b are formed on the inner surface of the rear portion 22 of the basket 20. The rear-stage groove portion 22b is a groove-like portion that does not penetrate the basket 20 in the thickness direction, like the above-described front-stage groove portion 21b. Each rear-stage groove portion 22 b has a linear shape extending in the central axis direction of the basket 20. The rear groove portions 22b are arranged in a plurality of rows in the circumferential direction of the basket 20, and gaps with a predetermined interval are formed between the respective rear groove portions 22b. Further, a plurality of round holes 22a are formed in each of the rear groove portions 22b. The round holes 22a are arranged along a straight line along the central axis direction so as to follow the shape of the rear groove portion 22b. The lateral width of each rear-stage groove portion 22b is larger than the lateral width of the round hole 22a. Therefore, the rear-stage groove portion 22b is formed so as to surround the circumference of the round hole 22a. Thus, by forming the rear-stage groove portion 22b around the round hole 22a, turbulent flow of the papermaking raw material can be generated in the vicinity of the round hole 22a. For this reason, even if a fiber lump is generated in the papermaking raw material, the fiber lump can be crushed and returned to a normal state by the turbulent flow generated in the vicinity of the round hole 22a. It is. Therefore, it is possible to prevent the foreign matters having hardened fibers from passing through the round hole 22a.

  Here, the embodiment has been described in which the slit 21a is formed in the front part 21 of the basket 20 and the round hole 22a is formed in the rear part 22. However, the round hole 22a is formed in the front part 21 and the slit is formed in the rear part 22. The embodiment in which 21a is formed can also be adopted. However, if a round hole 22a through which the papermaking raw material is easily passed is formed in the front stage portion 21 and a slit 21a through which the papermaking raw material is difficult to pass through is formed in the rear stage portion 22, there is a possibility that the meaning of performing selective selection by this slit 21a may be lost. Therefore, in order to enjoy the advantages of both the selection by the slit 21a and the selection by the round hole 22a, as described above, the embodiment in which the slit 21a is formed in the front part 21 and the round hole 22a is formed in the rear part 22 is adopted. It is preferable to do.

  Next, a screen system 100 in which a plurality of screen devices are connected in a cascade manner will be described with reference to FIG. In the example shown in FIG. 4, the screen system 100 includes a first screen device 10a, a second screen device 10b, and a third screen device 10c. Each of the screen devices 10a, 10b, and 10c basically selects a papermaking material introduced from the inlet, extracts a part of the selected papermaking material from the outlet, and discharges the papermaking material including foreign matters from the outlet. It has the function to do. Each of the screen devices 10a, 10b, and 10c is preferably a rotary screen device that uses a basket and a stirrer. It is also possible to use.

  As shown in FIG. 4, the outlet of the first screen device 10a is connected to the paper machine, and the outlet is connected to the inlet of the second screen device 10b. Further, the outlet of the second screen device 10a is connected to the inlet of the first screen device 10a, and the outlet thereof is connected to the inlet of the third connecting device 10c. Further, the outlet of the third screen device 10c is connected to the inlet of the second screen device 10b, and the outlet is connected to the waste disposal site. In this way, the papermaking raw material discharged as containing foreign substances in the upstream device is carefully selected in the downstream device, and the papermaking raw material selected as normal in this downstream device is again treated as upstream. The connection method introduced into the equipment is called the cascade method.

  Here, in such a cascade-type screen system 100, the second screen device 10b and the third screen device 10c located on the downstream side are rotary screen devices, and the basket according to the present invention is included therein. 20 is preferably mounted. As described above, the basket 20 according to the present invention is less likely to be clogged, has a high foreign substance removal accuracy, and can maintain the quality of the finally obtained paper. For this reason, by using the basket 20 according to the first side surface for the downstream screen devices 10b and 10c, it is possible to prevent clogging in the upstream screen device 10a. Thus, the basket 20 of the present invention is preferably used for the downstream screen devices 10b and 10c in the cascade screen system 100. Of course, the basket 20 of the present invention can be mounted on the first screen device 10a located at the most upstream. However, in the basket of the first screen device 10a, the shape of the hole for fine selection may consist of only a slit or only a round hole.

  As mentioned above, in this specification, in order to express the content of this invention, embodiment of this invention was described, referring drawings. However, the present invention is not limited to the above-described embodiments, but includes modifications and improvements obvious to those skilled in the art based on the matters described in the present specification.

  The present invention relates to a basket and a screen system for a papermaking material screen device. Therefore, the present invention can be suitably used in the paper industry.

DESCRIPTION OF SYMBOLS 10 ... Screen apparatus 10a ... 1st screen apparatus 10b ... 2nd screen apparatus 10c ... 3rd screen apparatus 11 ... Inlet 12 ... Stirring member 13 ... Storage tank 13a ... Primary chamber 13b ... Secondary chamber 14 ... Outlet 15 ... Discharge port 16 ... Rotating mechanism 16a ... Rotating part 16b ... Belt part 20 ... Basket 21 ... Front stage part 21a ... Slit 21b ... Front stage groove part 22 ... Rear stage part 22a ... Round hole 22b ... Rear stage groove part 23 ... Intermediate part 100 ... Screen system

Claims (7)

The papermaking raw material is introduced from the inlet (11), the introduced papermaking raw material is carefully selected in the storage tank (13) provided with the stirring member (12), and the selected papermaking raw material is led out from the outlet (14). In the screen device (10) for discharging the papermaking raw material containing foreign matter from the discharge port (15), a cylindrical screen basket (20) installed in the storage tank (13) and having the stirring member (12) installed therein. ) And
The basket (20)
It is composed of a member including a front part (21) located on the inlet (11) side and a rear part (22) located on the discharge port (15) side,
A plurality of slits (21a) through which a papermaking raw material passes are formed in a shape extending in the central axis direction of the basket (20) on the peripheral side portion of either the front stage portion (21) or the rear stage portion (22). ,
A basket in which a plurality of round holes (22a) through which the papermaking raw material passes are formed on the other peripheral side portion of the front portion (21) and the rear portion (22). The slit (21a) is formed in the peripheral side portion of the front portion (21),
The basket according to claim 1, wherein the round hole (22a) is formed in a peripheral side portion of the rear stage portion (22). The papermaking material in the storage tank (13) is carefully selected by passing through one of the slit (21a) and the round hole (22a), and is led out from the outlet (14). The basket according to claim 2. The basket (20) is composed of a member having an intermediate part (23) interposed between the front part (21) and the rear part (22),
The basket according to claim 2, wherein neither the slit (21a) nor the round hole (22a) is formed in the intermediate portion (23) over the entire circumferential direction of the basket (20). A plurality of rows of front groove portions (21b) extending in the central axis direction are formed on the inner surface of the peripheral side portion of the front portion (21) in the circumferential direction.
The basket according to any one of claims 1 to 4, wherein the slit (21a) or the round hole (22a) is formed in the front groove portion (21b). A plurality of rows of rear groove portions (22b) extending in the central axis direction are formed on the inner surface of the peripheral side portion of the rear portion (22) in the circumferential direction.
The basket according to any one of claims 1 to 5, wherein the slit (21a) or the round hole (22a) is formed in the rear groove portion (22b). A screen system (100) in which a plurality of screen devices are connected to select papermaking materials introduced from an inlet, lead out the selected papermaking materials from an outlet, and discharge papermaking materials containing foreign substances from an outlet. ,
The screen system (100) includes:
The outlet of the upstream screen device is connected to the inlet of the downstream screen device, and the outlet of the downstream screen device is connected to the inlet of one of the upstream screen devices. , Cascade connection method,
At least the downstream screen device
An inlet (11) through which papermaking raw materials are introduced;
A storage tank (13) for storing the papermaking raw material introduced into the inlet (11);
A stirring member (12) for stirring the papermaking raw material in the storage tank (13);
A cylindrical basket (20), which is installed in the storage tank (13) and is equipped with the stirring member (12) for selecting papermaking raw materials;
An outlet (14) for deriving papermaking raw materials selected by the basket (20);
A discharge port (15) for discharging a papermaking raw material containing foreign substances that is not carefully selected by the basket (20),
The basket (20)
It is composed of a member including a front part (21) located on the inlet (11) side and a rear part (22) located on the discharge port (15) side,
A plurality of slits (21a) through which a papermaking raw material passes are formed in a shape extending in the central axis direction of the basket (20) on the peripheral side portion of either the front stage portion (21) or the rear stage portion (22). ,
A screen system in which a plurality of round holes (22a) through which the papermaking raw material passes are formed on the other peripheral side portion of the front portion (21) and the rear portion (22).

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