JPS61186595A - Formation of screen cylinder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a screen cylinder that can be used for sentry screens, sentry sorters, barrier screens, etc.

(Prior Art) The pressure-type slit screen, which is well known as a paper valve sieving device, has an inlet 1 for paper stock at the top and an outlet for selected paper stock at the bottom, as shown in Figures 9 and 10. A casing 4 having a casing 2 and a resect outlet 3, a screen cylinder 5 having an elongated slit-like hole (hereinafter referred to as a slit) inside the casing 4, and a screen cylinder 5 that rotates at a small distance from the screen surface and is captured on the screen surface. It consists of an airfoil (hereinafter referred to as foil) 6 that serves to remove foreign matter and keep the screen surface clean. The purpose of this pressure-type slit screen for stock is:
The purpose is to capture and remove foreign objects such as plastics, bundled fibers, and wood chips that are larger than the opening size of the slits in the paper stock on the screen surface, while also allowing the fibers to pass through efficiently.

However, in the conventional screen cylinder structure, in order to prevent the slits from being clogged with fiber lumps, it is essential to rotate the foil 6 at high speed, and as a result, the paper stock also tangles at high speed. As a result, long fibers of good quality escape to the resect outlet 3 side, resulting in a decrease in fiber passage rate (yield) and serious drawbacks such as high power consumption.

Against this background, the inventors of the present invention have previously submitted a device (Utility Application No. 58-108190), in which a device is installed at the entrance corner of the slit as shown in Figs. A screen cylinder with a chamfered surface was devised in an attempt to eliminate the above-mentioned problems.

Figures 11 to 14 show an example of a screen cylinder in which the stock flows from the inside to the outside, and flanges 8 are attached to both ends of the cylindrical screen plate 7 for attachment to the main body of the screen device. The screen plate 7 is provided with a large number of slits 9 arranged circumferentially and substantially parallel to its axis. Furthermore, on the surface 10 of the screen plate 7 facing the paper stock inlet, there is a slit opening 11 which is straight in the thickness direction of the screen plate 7 and is composed of walls parallel to each other and spaced apart by a predetermined dimension. . At the almost right-angled inlet corner 12 where the surface of the screen plate 7 and the parallel wall intersect, if the trailing motion of the paper stock due to the rotation of the foil is in the direction of the arrow 13, there is an inlet corner on the downstream side of the flow. Chamfering 14 is applied. Further, on the back surface 15 of the screen plate facing the outlet of the paper stock, an escape groove 16 having an opening size sufficiently larger than the slit opening 11 is provided.

Next, a method of manufacturing a conventional screen cylinder without chamfering on the large corner of the slit will be explained with reference to FIGS. 15 and 16. In addition, the following (a) to (g) refer to the 15th
Corresponds to (a) to (g) in the figure.

(a) Cut relief grooves 16 on the flat plate using a specified pinch.

(b) Cut a slit opening 11 in a prescribed slit approximately in the center of the relief groove.

(c) Remove edges and burrs at both ends of the slit opening using a file or the like.

) Precisely bend the screen plate 7 to the specified diameter.

(e) Fix the longitudinal joints of the screen plate and g by welding. Remove the protrusion so that the weld bead is flush.

(F) Machining relief 1JS16 and slit opening 11 at the longitudinal joint portion of the screen plate.

(g) Attach flanges 8 to both ends of the screen plate and process the flange surfaces to the specified dimensions.

The conventional manufacturing method described above has the following serious drawbacks.

(a) The gap accuracy of the slit opening was poor.

Here, the gap accuracy can be defined by the degree of variation in the width of the slit opening of the finished screen cylinder with respect to the width of the slit defined in advance. It should be noted that if the finished dimension of the slit opening width is wider than the specified slit width, the ability to remove foreign matter will be reduced, and if it is narrower than the finished size of the slit, the ability to process the paper stock will be reduced, so either case is disadvantageous.

Here, a distribution curve for explanation is shown in FIG. 17.

The curve (b) in Fig. 17 corresponds to (b) in Figs. 15 and 16, and since processing is performed with a cutter having the same width as the width of the specified slit, the average value almost matches the specified slit and there is no variation. It's also small. 1) corresponds to 1) in FIG. 15, and as the inner diameter side contracts due to bending, the inside of the slit becomes narrower, and as the average value moves, the variation becomes larger. Moreover, the curve (E) corresponds to (E) in FIG. 15, and the variation becomes even larger due to local shrinkage due to welding heat input at the longitudinal joint.1. Gap accuracy decreases. The decrease in gap accuracy due to the subsequent manufacturing process is minimal. Generally, the degree of movement of the average value of the distribution curve (C in Figure 17) is 10 to 20% in the specified slit.
is within the range of

(mountain), the number of machining steps was high (machining efficiency was poor).

Since both ends of the slit opening form edges, if left as is, the fibers in the paper stock will become entangled and cause the slit to become clogged, making it unusable. For this reason, it was necessary to remove the edges with a file, as shown in FIGS. 15 and 16 (c). However, this work was done manually and had very low processing efficiency.

Further, in the slit machining of the joint portion in the longitudinal direction of the screen plate shown in FIG. 15(f), since the screen plate is cylindrical, the cutting process could not be automated and the machining efficiency was poor. Furthermore, slitting by a cutting means has a rough processed surface and produces burrs at the processed edges, so if left untreated, fibers in the paper stock will get caught. Therefore, it was necessary to perform electrolytic polishing to make the machined surface smooth. This results in a large number of machining steps and a long machining time, resulting in an expensive screen cylinder.

Next, the procedure for manufacturing a screen cylinder with a chamfered entrance corner of the slit using a conventional manufacturing method will be described with reference to FIGS. 18 and 19 (A), (B), and (C). Note that (a) to) below correspond to (a) to) in FIGS. 18 and 19.

(a) Cut relief grooves 16 at a specified pitch on the flat plate.

(b) Cut a slit opening 11 in a prescribed slit approximately in the center of the relief groove.

(c) Chamfer the entrance corner of the slit at the required angle and depth. Since this processing will be performed from the direction of the surface of the screen plate, it is necessary to reverse the screen plate and position it again.

2) Due to the chamfering process, burrs are generated along the entire length of the slit in a manner that covers the slit opening, so remove them together with the edges at both ends of the slit opening using a file or the like.

The subsequent manufacturing steps are the same as in) to (g) in FIG.

However, in this case, in addition to the drawbacks (a) and (mountain) mentioned above, there was the following serious drawback.

In other words, it was difficult to manufacture it in a narrow slit.

The slit depth B shown in FIG. 18(b) is deeper than the slit depth A in FIG. 15(b) by the depth of the chamfering process. The Tsuho B dimension is 1.5 to 2.5 times the F dimension. Therefore, the efficiency of cutting the slit opening 11 decreases, especially when the diameter is 0.25 m.
In the following narrow slits, damage to the cutter will be significant.
Processing was difficult.

In addition, the "burrs" caused by the chamfering shown in FIGS. 18 and 19) partially block the slit opening, and it is very difficult to remove the "burrs" in narrow slits. In other words, with conventional manufacturing methods, a screen cylinder with a chamfered entrance corner of the slit inevitably suffers from a significant drop in processing efficiency, and is difficult to manufacture when the slit is narrow. The present invention attempts to solve the problems of conventional screen cylinder manufacturing methods, such as poor slit opening gap accuracy and poor processing efficiency, and difficulty in manufacturing when the slit is narrow. It is something.

(Means and effects for solving the problem) Therefore, the present invention provides a method for manufacturing a screen cylinder for a pressure-type slit screen, in which rod-shaped pieces of arbitrary cross-sectional shapes are arranged in a cylindrical shape, and flanges are attached to both ends of the rod-shaped pieces. It is designed to be fixed.

(Example) Examples of the present invention will be described below with reference to the drawings. FIGS. 1 to 8 show examples of the present invention. In the figure, the twisting motion of the stock as the foil rotates is indicated by arrow 17 (Figure 4).
If the flow is in the direction of , the drawn material is manufactured with a cross-sectional shape that forms a chamfer at the large corner of the slit on the downstream side of the flow. Next, the drawn material is bent and straightened, and a necessary number of rod-like pieces 18 are prepared by cutting them into a predetermined length (dimension 0 in FIG. 2) in a highly straight state. On the other hand, the upper flange 19 and the lower flange 20 are provided with a groove 23 having a width approximately equal to the height of the rod-shaped piece 18 (dimension 8 in FIG. 4) and a guide groove 24 for fixing the guide ring 21. The flange surface required for assembling the screen cylinder is also finished to the specified dimensions in advance.

Precise and efficient positioning can be achieved by using the guide wheel 21 to assemble the bar-shaped piece 18 into a cylindrical shape within a pre-slit. As shown in FIG. 5, when the rod-shaped piece 18 has the cross-sectional shape of this embodiment, the guide ring 2
It is convenient to make the shape of part 1 into a saw blade shape as shown in the figure, because if it is assembled while being rotated in the direction of arrow 22, it will not be able to rotate in the normal position. Note that the accuracy of the slit and clearance of the screen cylinder is mainly determined by the shape and accuracy of the guide ring 21, so manufacturing the guide ring 21 requires particular precision. It is easy to process using a laser beam processing machine equipped with a numerical control device.

In the assembly procedure, first, the guide wheels 21 are attached to the guide grooves 24 of the upper flange 19 and the lower flange 200, respectively. Next, using a suitable jig (not shown), the distance between the bottoms of the grooves 23 of the opposing flanges is adjusted to the length of the rod-shaped piece 18, and the second
Assemble the upper and lower flanges so that they are approximately equal to the 0 dimension in the figure.

Furthermore, the rod-shaped pieces are sequentially inserted into the grooves of the flange, rotated in the direction of arrow 22 in FIG. 5, and fixed at a position where the rod-like pieces are in a normal position. Next, when all the rod-shaped pieces 18 have been assembled, they are restrained with a jig so that they do not move.

Once the assembly is complete, the upper and lower flanges 19.
20 and the rod-shaped piece 18 are fixed. Figure 6 (a) shows the assembled state, and as shown in figure 6 (b), the arrow 25
Fix the joint by welding from the direction. When selecting a welding method, it is desirable to use a method that does not require beveling of the welded area, causes less welding distortion, and provides a smooth bead surface. Specifically, electron beam welding or laser beam welding is effective.

When welding is completed, the saw-blade-shaped guide ring 21 is removed because it tends to catch fibers in the paper stock (FIG. 6(c)).

In addition, screen cylinders that use drawn material for the rod-shaped parts do not undergo any cutting on the finished surface, so there are no protrusions that can cause fibers to get caught, such as burrs that occur during processing, and electrolytic polishing is not possible. Not particularly necessary.

In the method of manufacturing the screen cylinder according to the embodiments of the present invention, the rod-shaped pieces 18 are not limited to the embodiments shown in FIGS. The cross-sectional shape may be any shape, and the manufacturing method may be a method outside the drawing method, such as cutting. Additionally, the flange surfaces of the upper and lower flanges 19 and 20 are machined using the rod-shaped parts 18
It may be carried out after welding of the flange and flange is completed. The method of assembling the rod-shaped piece 18 into a cylindrical shape in a defined slit is not limited to the method using the guide ring 21 of the embodiment, but may also include inserting shim plates equal to those in the defined slit above and below the slit opening, etc. Other methods may also be used. Further, the guide ring 21 is not limited to the embodiments shown in FIGS. 3 and 4, and may have any shape passing through the cross-sectional shape of the rod-shaped piece 18.
The manufacturing method also does not require the use of a laser beam processing machine.

Furthermore, the method of fixing the rod-shaped piece 18 and the flange 19.20 is as follows.
It is not limited to the welding means used in the examples, but includes diffusion welding, friction welding,
Other means such as brazing or adhesion may also be used. Further, the welding method is not limited to electron beam welding or laser beam welding, and other welding methods that satisfy the necessary conditions may be used.

(Effects of the Invention) As explained in detail above, the present invention has a screen cylinder in which rod-shaped pieces of arbitrary cross-sectional shapes are arranged in a cylindrical shape, and both ends of the rod-like parts are fixed with flange materials, so that the gap accuracy of the slit opening is can be increased.

That is, since the rod-shaped pieces are assembled into a cylindrical shape from the beginning with intervals only in the defined slits, there is no change in the slits due to bending. Furthermore, since there is no joint in the longitudinal direction of the screen cylinder, there is no change in the slit due to local thermal deformation during welding. Therefore, since the inside of the slit during assembly is maintained as it is until the finished state, high gap accuracy can be achieved.

Further, according to the present invention, the number of processing steps is small and processing efficiency is high. That is, since edges are not formed at both ends of the slit opening, there is no need for cleaning work with a file, and since there is no joint in the longitudinal direction of the screen cylinder, no additional slit processing is necessary. Further, when a rod-shaped piece formed by a drawing method is used, the surface is uniform and the "roughness" is smooth, so that electrolytic polishing can be omitted. Therefore, the number of machining steps is small (the machining time can also be shortened), and as a result, an inexpensive screen cylinder with a short manufacturing period can be manufactured.

Further, according to the present invention, it is possible to manufacture a narrow slit with an arbitrary cross-sectional shape. That is, since a rod-shaped piece formed by a drawing method or the like is used, not only a cross-sectional shape of the slit portion where the entrance corner of the slit is chamfered, but also a more complicated cross-sectional shape can be manufactured without changing the number of processing steps. Furthermore,
Since the slit width is achieved by arranging rod-shaped pieces at specified intervals, there is no decrease in processing efficiency even if the slit width becomes narrower. Screen cylinders with narrow slit widths of 0.25 fl or less can be easily created. can be manufactured.

As described above, in the present invention, the slit width at the time of assembly is maintained until the finished state, so the slit width distribution curve becomes as shown in Fig. 20, which is different from the conventional manufacturing method shown in Fig. 17 (E). In comparison, high gap accuracy can be achieved.

As a specific example, the diameter is 500 fl, and the specified slit width is 0.2.
fl, a screen cylinder with a pitch of 5.2 fl, the first
The gap accuracy was measured using the method shown in Figs. 6 to 6. The average value was 0.195 m, and the standard deviation was 0.014 mg+.

Further, in the present invention, if the bar-shaped piece is manufactured using a drawn material, electrolytic polishing can be omitted and the number of processing steps can be reduced.

7 and 8 show a comparison of the main manufacturing steps between the conventional method and the present invention. Figure 7 shows the case of the conventional manufacturing method, with a total number of man-hours of 14
The minimum required number of steps indicated by the thick arrow is ]3.

FIG. 8 shows the case of the present invention, which corresponds to the manufacturing method shown in FIGS. 1 to 6. The total number of man-hours is 7 (the total number of man-hours is 6 if the guide transfer is used repeatedly), and the minimum required number of man-hours indicated by the thick arrow is 5.
Compared to the conventional manufacturing method, the total number of man-hours is 2, the minimum required number of steps is 1/2.6, and the machining time is also shortened, so as a result, a screen cylinder with a short manufacturing time and low cost can be manufactured.

Furthermore, according to the present invention, a screen cylinder having a slit portion with an arbitrary cross-sectional shape can be manufactured with the same number of processing steps (
In conventional manufacturing methods, if the cross-sectional shape of the slit becomes complex, the number of processing steps increases accordingly.) Also, even if the slit width becomes narrower, the processing efficiency will not decrease.
A screen cylinder with a narrow slit width of 0.25W or less can also be easily manufactured by paying attention to the straightness of the rod-shaped pieces.

[Brief explanation of drawings]

FIG. 1 is a plan sectional view showing an example of a screen cylinder obtained by the method of the present invention, FIG. 2 is a front sectional view of the same, FIG. 3 is a detailed view of the Y section in FIG. 2, and FIG. Details of section X in Figure 1
Figure 5 is an explanatory diagram showing the assembled state of the rod-shaped piece in Figure 4, Figures 6 (A), (B), and (C) are explanatory diagrams of the fixing order of the flange and the rod-shaped piece, and Figure 7 Figure 8 is a block diagram showing a conventional method for manufacturing a screen cylinder, Figure 8 is a block diagram showing an embodiment of the method of the present invention, Figure 9 is a plan view of a conventional pressure type screen plate, and Figure 10 is a front cross-section of the same. 11 is a perspective view of a conventionally proposed screen cylinder,
Figure 12 is a sectional view taken along line A-A in Figure 11, and Figure 13 is a cross-sectional view of Figure 12.
BB sectional view in the figure, Figure 14 is a detailed view of the Z section in Figure 13,
Figures 15 (A), (B), (C), (E), (F), and Figures 16 (A), (B), and (C) sequentially show an example of the conventional screen cylinder manufacturing method. An explanatory diagram, FIG. 17 is a distribution curve diagram of slit openings of a conventional screen cylinder,
Figure 18 (a) (b) (c)) and Figure 19 (a) (
B) (C)) is an explanatory diagram of a screen cylinder manufacturing method of an embodiment different from the conventional FIGS. 15 and 16, and FIG. FIG. 20 is a distribution curve diagram of the slit width in the present invention and the conventional method. Explanation of the main parts of the figure 1B--Bar-shaped piece 19--Upper flange 20--Lower flange 21--Guide export 23--Flange groove Patent Applicant: Mitsubishi Heavy Industries, Ltd. No. 11 figure
Fig. 42 Fig. 14 Fig. 13/l 10/mu Fig. 16 Fig. 17 Fig. 18 b Fig. 19 Procedural amendments August 7, 1985 Director General of the Patent Office Uga Michibe 1, Indication of the case Patent Application No. 60-21933 2, Name of the invention Method for manufacturing screen cylinders 3, Relationship with the case of the person making the amendment Patent applicant address 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Name
(620) Mitsubishi Heavy Industries, Ltd. 4, Agent Address: 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Heavy Industries, Ltd. Name (6124) Patent Attorney Board: Akatsuki Hama, 2 others 5,
Sub-Agent 7, column for detailed explanation of the invention subject to amendment, column for brief explanation of drawings, content of amendment 1, “Centry screen, ~screen, etc.” on page 1, lines 12-13 of the specification. is corrected to ``The sifting of raw materials for paper manufacturing is carried out by equipment, etc.'' 2. Correct "motion" on page 3, line 18, and page 9, line 18, to "flow." 3゜Correct "pre-swaging" on page 10, line 11 of the same page to "pre-caulking". 4. In the third line of page 11 of the same page, amend "It's fine." to "It's fine." 5. "Can be manufactured." in the second line of page 15 of the same page was corrected to "Can be manufactured. (In conventional manufacturing methods, if the cross-sectional shape of the slit becomes complex, the number of processing steps increases accordingly.)" 6゜ "Screen plate" on page 17, lines 6-7.
is corrected as "slit screen". 7. Correct the drawings in Figures 7, 8, and 18 (b) as shown in the attached sheet. that's all

Claims (1)

[Claims] A method of manufacturing a screen cylinder for a pressure-type slit screen, which comprises arranging rod-shaped pieces of arbitrary cross-sectional shapes in a cylindrical shape and fixing flange members to both ends thereof.