JPS59137593A - Screening apparatus for papermaking stock material - 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 In a paper factory, a cylindrical screen member with small holes is used in a closed No-Ujifugu, and a cylindrical screen member with small holes is used to partition supply and receiving chambers on both sides. Screening devices for cleaning papermaking stock have been used for many years that include a rotor member operating in one chamber to keep the holes open and unaffected by solid materials that tend to stick to the screen surface. It has been widely used. Generally, the stock or feed is fed into a feed chamber adjacent one end of the screen cylinder - and material rejected from the screen cylinder is collected and discharged from the opposite end of the feed chamber.

The assignee of this invention has a series of U.S. patents, beginning with 'Staege' patent no. 2.347,716, followed by Martin
d-ale) Patent No. 2,835,173 to Seifert Patent No. 3,849.30
2 and 4,105,543 and Chupka-8eifert's Patent No. 4,1
No. 55,841, many such screens have been manufactured and sold.

Beginning with the construction shown in the Martindale patent, all of the screens manufactured and sold by the assignee of the present applicant have been designed to have positive and negative effects acting on the apertures of the screen cylinder to prevent clogging. to produce alternating pressure waves of
At a slight distance from the screen cylinder surface,
It is characterized by a rotor that includes vanes with rods or wing-like sections that move without contact.

In the above-mentioned types of screens, this technique has been extensively experimented with by changing the details, i.e. by changing the shape of the vanes, by making the rotor a different shape, and by changing the size-shape and spacing of the small holes in the screen cylinder. I went. Thus--since the days of Stage's patents in the mid-1940's, many screen cylinders have been manufactured with a plurality of uniform cylindrical drill holes generally ranging from about 0.050 inch to 0.125 inch.

In more recent times - the small holes in the screen cylinder are not round holes but elongated slots, the slots running either circumferentially or axially of the cylinder;
Pressure screens of the type described above are commonly sold. Its typical structure is -Lamort
) Patent No. 3.61'7.008, Horn (HO
IZ) patent 3,581,903, and the Seifer) '302 and Chapkar Seifert patents mentioned above.

In addition to the slotted cylinder, the Ramote and Chapker-Seifert patents both include a plurality of generally axially extending shoulders or shoulders spaced circumferentially on the interior of the cylinder. A small rod is also shown. The roller configuration is described as preventing clogging of the screen slits by fibers in a manner not described by Ramote. In the Chapkar Seifert patent,
The purpose of the rod is to create a strong fine-scale turbulence field in the stock adjacent to the inlet side of the screen cylinder, thereby improving its fractionation on the basis of fiber length (frac
It is explained that the method is to carry out in-cleaning of the paper fiber stock by minimizing the tionation.

Chapkar Safe Art's patent disclosure is simply 0001
Limited to screen cylinders with circumferentially extending slots having widths in the range of .about.0008 inches. Chapkar Seifert's later application, Ser. Applied to a circumferentially extending screen cylinder having a width of ~0.022 inches, the screen capacity was increased both in terms of power required per unit time and per unit fiber received. something is shown.

Ronald F, 5
No. 430.475, filed September 60, 1982, a single-pressure filter screen has a circular or vertical slot-like screen hole - and a circumferential hole on its inlet side. It has been disclosed that a dramatic improvement in the performance of the screen can be achieved if the screen cylinder is provided with a plurality of rods spaced apart in the same manner. Particularly when compared to the standard screen according to the Seifert patent mentioned above, which has round holes in the screen cylinder, the screen with the above device consisting of circumferentially spaced rods on its inlet side - through smaller holes. While screening the stock with higher consistency, the amount of fiber (tons) accepted per m-day is greater and the power per unit of fiber received is also less.

Realizing the advantages of the multi-rod screen cylinder disclosed in the Chapkar Safeart '7841 patent and the Secor application discussed above specifically reduces the number of contaminant particles that are larger in cross-section than the paper fibers. This is not possible because it has not been previously possible to manufacture screen cylinders with round holes or narrow slots as small as necessary to eliminate there were.

More specifically, Chapkar Seifert's patent 78
No. 41 discloses a screen cylinder with a circumferentially extending slot having a width in the range of 0,001 to 0,008 inches; however, as disclosed in that patent, the cylinder is spirally shaped. Even when made of wound wire, it is extremely difficult to obtain narrow slots with the above-mentioned core. Additionally, slots parallel to the axis of the screen cylinder are most conveniently made with saw teeth, making them suitable for use in steel or other metals that are sufficiently hard to be used as screen cylinders. The minimum thickness of the slot determines the practical minimum value of the slot.

During the development of the present invention, it was determined as a practical matter that the minimum width that could be maintained in a screen having circumferential slots formed by a spiral wrap was not less than 0.0101 inch; The minimum width obtained by saw teeth in a screen cylinder with slots parallel to its axis is 0
．． It turned out to be about 0.006 inches. Similarly, the minimum practical diameter of a cylindrical hole drilled in a typical screen cylinder steel plate is about 0.050 inch, even if the stainless steel is 16 inches thick, and about 0.05 inch in diameter. It was found that it was not possible to punch holes smaller than the 03 finch.

The present invention addresses this problem by attempting a completely different approach to its ultimate goal of obtaining uniformly sized screen holes and circular holes with the smallest practical width or diameter. Settled. The approach begins with the minimum dimensions that can maintain uniformity - approximately 0.06" wide for slots parallel to the axis and 0.06" wide for slots extending circumferentially. The goal is to create the desired slot or hole with a diameter of .010 to 0.014 inches and 0.050 inch for round holes. These dimensions for round holes and axially extending slots are thickness melting. ~Applicable to 6-inch steel plates, and the drilling and sawing operations are carried out either before or after welding multiple rods to their entrance sides, followed by rolling and welding of the flat into a cylindrical shape. Performed on steel plates.

The cylindrical body with the oversized hole or slot and its rod is then coated so as to completely cover its inner and outer surfaces with a smooth coating of a predetermined uniform thickness. , and also forming a lining on the wall of each hole or slot,
The smallest dimension is reduced by an amount substantially equal to twice the thickness of the coating.

In practicing the present invention, the preferred result is that of Gutzeit et al., 1956 Patent No. 2.6.
No. 58,840 or Encyclopidia of Eng published by Relnhold in 1963.
ineering hAterialsarid P
G in rocess, 'El by Gutzeit
electroless Nickel Coatings”
It was obtained by an electroless nickel coating applying an artisanal technique as described in the section titled . The coating has the desired adhesion to steel and a controlled uniform thickness such that the holes have an initial diameter of 0.05'O inch and the slots have a minimum width of 0.014 inch. A circumferentially extending slot having a width of 0.006 inches or an axially extending slot having a width of -0001 inches and a hole having a uniform minimum diameter of 0.001 inches. A slot with a uniform minimum width is obtained.

The presence of these small sized screen holes provides significant advantages in the cleanliness of the accepted stock;
This is because the capacity of the pores to remove small contaminant particles that are about the same size as good paper fibers is greatly increased. In addition, such small pores have a strong tendency to become clogged or blocked by the fibers felting the inlet end; According to Secor's application, in the case of multiple bars along one side -
It has been confirmed that the capacity of the screen is surprisingly high. Test results supporting this point will be discussed below in connection with the description of the illustrated preferred embodiment of the invention.

In order to more easily understand the invention, reference will now be made in detail to the accompanying drawings. The screening device shown in FIG.
, 105,543. it is,
It comprises a main housing 10 on a base 11 and the upper end of this housing has a tangential inlet 13 for delivering the feed under pressure, as is customary in such screening devices. It serves as an inlet chamber 12.

A cylindrical screening control 5 with a plurality of circular holes 16 divides the interior of the housing below the chamber 12 into a central supply chamber 17 and a receiving chamber 18 with an outlet 19 .

The bottom wall 20 of the feed chamber adjoins an outlet 22 (comprising a trough 21) with a control valve arrangement 23 which can be configured to provide the desired continuous feed of reject-rich stock. The heavy particles settled in this gutter 21 are removed from there by a manual control valve 25 for intermittent removal into a heavy debris collection box 2.
It falls during the 4th.

The rotor 30 is mounted on the drive shaft 3 in the center of the supply chamber 17.
1 and driven by a motor 33, also mounted on the base 11, via a suitable gearing or belt. The airfoils or rods 35 are mounted on the rotor 30 by support rods 36 and are aligned with the inner surface of the screening member 15 by an adjustable connection 37 between the inner end of the rod 36 and the rotor 30. It is possible to position them at different intervals.

The wings 35 extend the entire length of the screen surface of the screen member 15 and are preferably helically curved;
and the upper end of each blade is in the rotational direction of the rotor,
They are configured to be arranged at intervals in front of the lower end. Although two wings 35 are shown, generally a greater number of wings 35 may provide improved operation with greater consistency.

Screening cylinder 15 is provided along its inner (inlet) face with a plurality of bars 40, shown as having an essentially rectangular cross section, which bars 40 are circumferentially spaced apart. The member 150 extends generally in its axial direction and cooperates with the surface portions of the member 150 to form a series of shallow pockets 42 therebetween. The radial dimension between the airfoil 35 and the radially inner surface of the rod 40 is relatively small and preferably stationary.

It is about an inch, but about 0.010 to 0.03
It can be varied within a range of 75 inches.

Significant results in the tests of the present invention were obtained with rectangular bars having a width of one inch on each side and spaced two inches apart, although these values can vary considerably. For example, the spacing between adjacent bars can range from 1 to 5 inches by varying the number of bars, and the dimensions of a rectangular bar are -
Heat on the side.

It can be in the range of ~1 inch. When using a rectangular bar,
Its larger dimension preferably extends in the radial direction of the screen cylinder in order to minimize the reduction of open screen area.

As previously pointed out, the present invention particularly provides a uniform screen hole 16 that is much smaller than previous ones, i.e. 0.0 in diameter.
It concerns the manufacture of cylindrical holes as large as 10 inches. With particular reference to FIG. 2, one technique of the present invention is to drill holes 16 in the steel plate 15 with a small drill that can be suitably used in pre-six inch thick steel plates. Based on actual experience, the maximum/F diameter is approximately o, o! 5 o inches, and the exit end of each hole is widened as shown.

After the perforated plate has been provided with the desired rod 40 and rolled and welded into the appropriate cylindrical shape - an electroless nickel coating is applied - during which a coating 44 of uniform thickness is applied over the entire surface of the cylindrical body. deposits, thereby also forming a lining for each hole 16 and correspondingly reducing the hole diameter. For example, if the holes 16 were initially drilled with a diameter of 0.050 inches, the thickness of the coating 44 would be adjusted to 0.0125 inches to reduce the final diameter of each hole 16 by 0.0- I can fit a 25 inch wife.

In operation, the natural result of the rotary motion in the circular path of the wings 350 is to produce a similar rotation in the annular layer of stock adjacent the inner surface of the cylinder 15. However, this movement of the stock is interrupted by the continuously provided rod 40, so that the outer part of the rotating layer is stripped off and branched into cooperating pockets 42.

The stock branched into each pocket 42 has a large circular moment--and therefore has a tendency to reverse its direction of flow in the pocket into which it branches. The action of the vanes also creates an alternating pressure through the holes 16, which is radially outward as each wing approaches each pocket, and radially inward as each wing passes through the pocket. , the combination of forces produces a high degree of local turbulence in each pocket.

At the same time, the interior of the feed nayamba is under continuous pressure from the pump, whereby the stock is fed to the screen - and thus the stock is passed through the holes 16 into the receiving chamber 1.
There is a power to continuously discharge in 8. The turbulence in the pockets has the effect of keeping the orientation of the fibers in each pocket under constant conditions that randomly change the orientation, thereby inter alia
Otherwise, it will tend to align tangentially to the cylinder and pass over the hole 16 instead of passing through it. For long fibers, their passage through the holes 16 can be increased.

The validity of this theoretical explanation of the operation of the screen of the invention, together with the practical importance of screen cylinders with particularly small holes, has been fully demonstrated by tests. In this way, in a series of tests, the Secor (
Secor) and having apertures for the 0.050 inch diameter screech and the screen cylinder having only 0.025 inch diameter holes as described above. A comparison was made between the screen and the screen according to the present invention. Both screens have a diameter of 2
393 x 4 inches and equally spaced along its inner surface
It had a k inch rod 40.

For each screen, the same two feed stocks were used, one with a clean corrugated stock and one with a solid reject of 2.5
% was added to the corrugated paper stock.

The same operating conditions were applied to both screens for all runs: rotor speed of 680 r, p, m, and pressure drop of 8 psi. In the summary below ~Operation 1
A screen with 0.050 inch holes is used for the clean stock in ~3 - and the dirty stock in steps 4 - 6, while the clean stock in steps 7 - 9, and the dirty stock in steps 4 - 6 are used. 1
For 0-12 soiled stocks, a 0.025 inch child 1 screen was used.

The results of this test are surprising even considering only the comparison of each run on one clean stock. In fact, with respect to operation 7, it is surprising that the screen works perfectly and there is almost no instantaneous clogging of the received stock or blocking of its passage. However, in run 7, one inventive screen accepts 80 percent of the feed stock at a solid consistency of 3.29 percent, and this value means that each hole has a flow area four times that of the larger hole. and had a feed rate equal to about %.

Similarly, in processing soiled stock, the screens of the present invention can be processed at approximately the feed rate of a screen with a consistency greater than 350 percent, apertures four times larger, and The acceptance/rejection rate is still 70% compared to 83% for larger pores which necessarily accept many contaminant particles that are too thick to be accepted by the 0.025 inch pores of the present screen. Met. This greatly increased cleanliness improvement for the received stock would more than compensate for the relatively small reduction in capacity.

Figures 4-5 - Seifert Patent No. 3,849,60
An application of the invention to an axially slotted screen cylinder similar to that shown in No. 2 is shown. The cylinder 50 is provided with a plurality of screening slots extending vertically, i.e. in the axial direction of the cylinder, in circumferentially extending rows spaced apart in the axial direction. Except for this, it is formed similarly to the cylinder 15. This screening cylinder also has the same dimensions as described in connection with Figures 1-2, but with a straight cylinder extending in the axial direction of the cylinder.
It has a plurality of rods 52 welded along its inlet side.

In manufacturing the cylinder 50 according to the invention - the screen slot 51 is first sawed using a circular saw as thin as practical on a 6 inch thick steel plate. Practical experience has shown that by this method of sawing it is possible to maintain a constant width slot of 0.006 inch, and in which case the cylinder is coated 55 with a slot width of 51KQ. and the desired minimum,
0 to obtain a slot width of -0,001 inches.
．． An electroless nickel coating is applied to reach a coating thickness of 0.025 inches.

4-7 show y-triangular cross-sections spaced apart along the axis of the cylinder, constructed similarly to that disclosed in the above-mentioned Chapker-Seifert patents and applications. It is shown as applied to a screening cylinder 6o consisting of a series of rings 61 made of wire with .

According to the Chapker Seifert patents and applications - the screening cylinder can be made either by stacking a series of rings 61 in a suitable jig or by welding wire in a circular fashion. However, by any of these techniques, approximately 0.01
It has been found that it is easier to do this if it is smaller than 0 inches and larger than that.

According to the invention, any technique for forming the cylinder 6o has a uniform width that can be practically maintained, i.e. 0.
It can be used to make screens with circumferentially extending slots having widths as small as 0.010-0.014 inches. The completed screen, with the rods 63 welded in place, is then coated with an electroless nickel coating until the desired uniform thickness of the coating is achieved. If the initial slot width was 0.014 inches and the desired slot width was <), 002 inches, then the coating thickness should be o, o 06 inches.

Although the present invention is not limited in principle to the use of electroless nickel coatings, the characteristics of electroless nickel coatings include that they adhere strongly to steel and have uniform thickness and smoothness. The properties can be easily controlled and coated metal results can be obtained. This latter property allows the linear pores or slots to be accurately reproduced in the coating, resulting in the desired final minimum diameter of the entrance end of the screen holes.

The principles of the present invention can be applied to materials other than steel plates as the body base of a screen cylinder, and can also be applied to other coating materials. For example, screen cylinders are made of certain plastics, as well as polypropylene.
Similarly, the coating material can be any material other than nickel with suitable hardness and strength, and should adhere to the fuselage substrate with the desired strength - and with sufficient precision on the coated fuselage. ) Any material may be used as long as it reproduces the The selection of both the material of the monocylindrical substrate and the material to be coated is therefore at the discretion of those skilled in the art in the selection and use of said materials guided by the principles of the invention as set forth above and in the claims. It is.

Although it is generally easier and therefore preferred to coat the entire internal and external surfaces of the cylinder as well as the walls of the screen holes, it is possible to reduce the minimum dimensions of each hole to the desired value by suitable masking means. It is also to be understood that it is possible that only the walls of the pores that need to be reduced can be coated according to the principles of the invention as described above and can be of any thickness.

Although devices having the configuration described above constitute preferred embodiments of the invention, it is understood that the invention is not limited to these devices per se, and as defined in the appended claims. It will be understood that changes may be made thereto without departing from the scope of the invention.

[Brief explanation of the drawing]

1 is a perspective view, partially cut away, of a pressure screening device having a screen cylinder embodying the invention and equipped with circular screen holes; FIG. 2 is a perspective view of the screen cylinder 7 in the device of FIG. 1; 3 is an enlarged partial view of the screen of FIG. 1 taken in a section through the screen cylinder; FIG. 4 is a schematic diagram showing the top surface of the rotor; FIG. 4 shows a screen having a slotted screen hole extending in the axial direction of the cylinder; A schematic diagram showing a screen cylinder according to the present invention; FIG. 5 is an enlarged partial view of the screen cylinder of FIG. 4 in a radial cross section; FIG. FIG. 7 is an enlarged schematic view taken along line 7-7 of FIG. 6; FIG. Patent applicant The Plack Clawson Kannoguny (4 others) FIG-2 FIG-5 FIG-6 FIG-7

Claims (1)

[Claims] 1. The screen member has a plurality of through holes (16, 51, 62) having a predetermined maximum/JS cross-sectional dimension and reduces the cross-sectional dimension of each hole to a predetermined level; Housing 00 of a screening device for paper fiber stocks, characterized in that it includes a coating (44, 55, 65) forming the lining of each of the holes.
) said screen member installed in said screen member separating said interior into a supply chamber and a receiving chamber; 2. The screen member according to claim 1, wherein the mesh is made of metal, and the coating is made of electroless nickel. 3. A screen member according to claim 1, characterized in that said holes (16) have a circular radial cross section and said predetermined dimension is the minimum diameter of each said hole. 4. The holes are parallel slots I-(51, 62),
The screen member according to claim 1, wherein said predetermined dimension is the minimum width of each of said slots. 5. The copper substrate, together with the adjacent surface of the mesh, has a series of pockets (42) spaced closely and uniformly spaced circumferentially and generally extending in its axial direction to define a series of pockets (42). The net has a plurality of rods (40, 52, 63) fixedly attached to its entrance side, and the dimensions of each of the rods (40, 52, 63) measured in the radial direction of the net are as described above. The screen member according to claim 1, characterized in that the screen member is sufficient to interrupt the circulation of paper stock immediately adjacent to the inlet side of the screen member.6. a predetermined uniform thickness covering the outer surface and also forming a lining for the walls of each of said holes, reducing the cross-sectional dimension of each hole by an amount corresponding to substantially twice the thickness of the coating; installed in a housing α0) in a screening device for one-sheet fiber stock, characterized in that it includes a cylindrical copper substrate with a smooth coating (44°55.65) on it; The screen member separating the interior into a supply chamber and a receiving chamber. 7. The screen member according to claim 6, wherein said material is made of metal, and said coating is made of electroless nickel. 8. Screen member according to claim 6, characterized in that said holes (16) are circular in radial cross section and said predetermined dimension is the minimum diameter of each said hole. 9. The above holes are parallel slots) (51, 62),
7. The screen member according to claim 6, wherein the predetermined dimension is the minimum width of each of the slots. 10. The screen member according to claim 9, wherein said slot (51) extends parallel to said axis. 11. Claim 9, characterized in that said slot (62) extends substantially circumferentially for said purpose.
The screen section described in Section '#. 12. The copper substrate is generally circumferentially spaced relatively closely spaced at uniform intervals to define a series of pockets (42) with said adjacent surfaces. A plurality of rods (40, 52, 60) extending in the axial direction are fixedly attached to the inlet side thereof, and each rod (40, 52, 63) has a plurality of rods (40, 52, 60) extending in the radial direction. Claim 6, wherein the measured dimensions are sufficient to prevent circulation of stock immediately adjacent to the inlet side of the screen member, and wherein the coating covers the bar. Screen member described. 13. Said copper substrate, together with said adjacent surface, generally have said pockets (42) disposed relatively close to each other circumferentially at uniform intervals to define a series of pockets (42); It has a plurality of axially extending rods (40, 52° 63) fixedly attached to its inlet side, and each of the rods (40, 52° 63)
40, 52, 63) are sufficient to prevent stock circulation immediately adjacent to the inlet side of the screen member, and the coating covers the bar. The screen member according to claim 7, characterized in that: 14. said copper substrate, together with said adjacent surface, generally arranged circumferentially relatively close together to define a series of pockets (42); The screen member has a plurality of rods (40) extending in the axial direction fixed to the inlet side thereof, and the dimension of each of the rods (40) measured in the radial direction is the same as that of the screen member. 9. Screen according to claim 8, characterized in that the coating (44) is sufficient to prevent the circulation of stock immediately adjacent to the inlet side of the screen, and that said coating (44) covers said rod (49). 15. Members. 15. Said trunk body side generally axially disposed circumferentially relatively closely spaced at uniform intervals to define, with said adjacent surfaces, a series of pockets. It has a plurality of extending rods (52) fixed to the inlet side thereof, and the dimension measured in the radial direction of each of the rods (52) is equal to the paper closest to the inlet side of the screen member. 10. Screen element according to claim 9, characterized in that said coating (65) is sufficient to prevent circulation of materials and said coating (65) covers said bars.