JPH0359188A - New suction box cover - Google Patents

Abstract

PURPOSE: To provide a novel type of suction box cover that is equipped with the cover that is fixed to the main body that is linked to the vacuum source and is provided on the press-fabric passage and with the slot that includes the zigzag patterned segments communicating to the main body, and can reduce the flexure of the fabric and the noises. CONSTITUTION: In a paper-making machine that is equipped with a press fabric continuously moving in the passage that are preliminarily selected in the longitudinal direction in order to extract water from the whole paper, the suction box 10 comprises the main body of the box linked to the vacuum source and the cover fixed to the box main body 12 and this cover is arranged so that it may come into contact with the press fabric 22. This cover 16 has the slot that communicates to the box main body 12 so that water is extracted from press fabric by suction and this slot 18 is constituted with a plurality of slot segments 18' and 18" having the zigzag patterns formed to construct the objective suction box 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved cover for a suction box used in paper and board making equipment adapted to remove water by suction from a moving fabric or web.

b' of! H Various types of paper can be manufactured quickly and economically using so-called paper manufacturing equipment. The device dispenses a slurry of wood bulbs and other materials onto an endless forming fabric.

The forming fabric carrying the slurry is moved across a plurality of suction boxes which are used to remove water from the slurry to form a continuous sheet of paper. Since this whole paper has a high water content, it is transferred to a press section where it is brought into contact with at least one continuous press fabric and passed through a press nib to further remove water by mechanical means. . One more press fabric
Press pre-lifts are typically made to be woven to form a continuous fabric or the two opposing ends are joined by a seam. It is made from mixed materials.

Other types of papermaking equipment also exist, in particular equipment for producing multilayer laminated paperboard for industrial applications such as gypsum board and paper packaging tubes. In this case, the sheets are formed directly into a fabric in layers. The raw material is introduced into a vat filled with the raw material through a cylinder or by using a number of small forming wires. As the press fabric passes through each rotating cylinder it picks up layers of raw material. The fabric is then conveyed in this layered sheet through a number of presses in the usual sense. In this case, therefore, the fabricator has a foraging function and a compressing function.

In this case, the suction box is also used to remove water from the fabric. This type of paper machine is slow;
Also, “making fabric”
Although the fabric lifters used as ric)j are relatively light in weight, the principles of dewatering and compaction and the requirements of the fabric lifters are essentially the same.

The suction box usually has a cover with a straight slot extending across the width of the press fabric. The slot dimensions range from 378# to 3# in linear length.

(Although the suction box is described here as part of the press section of the paper machine, it should be understood that it may also be used in the forming section.) This type of suction box is unsatisfactory for a number of reasons. I understand. For example, when a seamed press fabric is used, the fabricator makes a loud and unpleasant popping sound as the seam passes through the slot, which is not only irritating but also reduces the overall noise level produced by the equipment. increase. The seam also rubs the green of the slot, causing the seam flap made from the raw material to wear out before the rest of the fabric. The useful life of the press fabric is thus rapidly reduced. The fabric also suffers from fabric deflection caused by the edge of the slot. Another type of sacsi-bon box cover is also used in which the slots are formed in a so-called herringbone pattern. These slots are usually defined by at least four contact edges. It has been found that this type of cover is also unsatisfactory, as wear and tear of the fabric increases as the number of edges traversed by the fabricator increases. This wear and tear is more pronounced in seamed fabrics because, as discussed above, the seam flaps wear away more quickly. Another reason is that the open area (length x width) of a Herringbone force bar is larger than a single straight slot. This reduces both the specific air flow rate (volume/area) and vacuum level, thus reducing the system's ability to adequately dewater the press fabric. Overcoming this problem would require a larger vacuum source, requiring capital expenditures and increased operating costs.

In view of the above-mentioned shortcomings of the existing suction box cover, the purpose of the present invention is to solve the problem of press fabrication and two moving directions (
An object of the present invention is to provide an improved suction box cover with slot edges that are angled with respect to the longitudinal direction, thereby extending the useful life of the press flap and overall structure.

Another object is to provide an improved box cover in which deflection of the fiber hooks in the slots is eliminated.

Another object is to provide an improved box cover that is adapted to reduce or eliminate the sounds produced by conventional box covers.

Another object is to provide a suction box force bar in which the number of edges traversed by the breather flaps is reduced.Other advantages of the invention will become apparent from the detailed description of the invention. .

To begin with, a suction box constructed in accordance with the present invention comprises a body connected to a vacuum source to provide suction. A cover is secured to the body and constructed and arranged to support press fabric that moves continuously across the cover. The box cover has a slot extending substantially transversely (i.e., transversely) across the width of the fabric, the slot communicating with the body of the box to apply suction to the fabric to draw water from the fabric. It is designed to be removed.

Advantageously, the effective area of the slot is substantially equal to the area of the transverse slot, and the slot has a plurality of straight slot segments, each segment being arranged at an angle of about 45 degrees with respect to the longitudinal direction. There is. The slot segments are connected end-to-end to form a continuous zigzag pattern across the width of the fabricator.

Referring to the drawings, a suction box 10 constructed in accordance with the present invention has a vacuum t
A (not shown). The box has a cover 16 secured to the body in a known manner. For example, in FIG. 1, cover 16 is connected to the body by a dovetail joint. Although fixed, other types of connections may be suitably operated in a similar manner.

The cover has a single slot 18) 18 consisting of a plurality of substantially straight slot segments, for example as indicated by reference numerals 18' and 18', each segment extending in the longitudinal direction as indicated by arrow 20. It is arranged at an angle of about 45 degrees with respect to the The segments are joined end-to-end such that two adjacent segments are perpendicular to each other to form a continuous zigzag pattern as shown in FIG. Each segment may be approximately 15 inches long, for example.

Next, a suction box with an improved cover will be described. The suction box is located on the paper machine, for example along the continuous path of the press fabric 22 in the press section of the paper machine. The press fabric link 22 traverses the cover in a continuous movement indicated by arrow 20. suction box 10
The vacuum removes water from the fabric through slots 18. As shown in FIG. 2, the fabric 22 across the box cover overlaps only a small number of the relatively narrow slot portions of the slots. For example, imaginary line 2
The portion of the fabric that traverses the 4 overlaps each of the 5 slot segments. Between these segments the fabric is completely supported by the box cover so that the fabric does not run on the edge transverse to its direction of movement, thus preventing friction between the fabric and the box cover and a single transverse slot. Wear of the fabric and its seam wrap (if any) resulting from fabricator bias is reduced compared to conventional box covers. The boxes shown in Figures 1-3 may be placed in the forming part to remove water directly from the girder web through the forming fabric.
Comparing Fig. 4 with Fig. 2 along vAA-B, vAA
- The fabric region along B has to pass through four edges or slot edges when the fabric region moves through a conventional Herringbone Bonx force bar. The fabric area passing through only the edges of the two slots substantially reduces wear.

In order to prove the validity of this concept, we conducted the following series of experiments. Pilot press sections using various seamed press fabric designs were used to examine the effect of cover design on seam flaps and overall wear of the press fabric surface. All covers were made of the same material. The open area of the box was constant at 1 square inch per inch of width.

This ensures the same airflow and vacuum conditions for all box covers, with the exception of the standard herringbone cover, which has an open slot area of 1.73 square meters per inch of width of the device. It was made to have an inch. All other operating conditions were held constant. Visual observations were made of the flap area after various operating times. The results are summarized in Table 1.

Table 1 Standard ring bong with 24 flats on fist cover (Fig. 4) Good Straight slot that cannot be detected Very poor Very large jig zug (1st to 3rd)
Figure) Superior Imperceptible Preferably the cover is molded from an impact resistant material with a low coefficient of friction such as polyethylene, although other materials such as silicon nitride and ceramics can also be used. Naturally, many modifications can be made to the invention, such as slot openings and slot angles, without departing from the scope of the claims.

[Brief explanation of drawings]

FIG. 1 is an isometric view of a suction box with a novel cover constructed in accordance with the present invention. FIG. 2 is a plan view of the cover of FIG. 1. FIG. 3 is a side view of the cover of FIGS. 1 and 2 with the press belt traversing the seam. FIG. 4 is a top view of a prior art suction box with a standard herringbone cover. 10...Suction box, 12...Main body, 14
... Connecting bin, 16... Cover, 18... Single slot, 22... Press fabric.

Claims (10)

[Claims] (1) A suction box for removing water from a continuously moving press fabric in a papermaking machine, having a body connected to a vacuum source; and an elongated slot fixed to and in communication with the body. a suction box including a cover extending substantially transversely to the preselected direction, the slots including a plurality of slot segments forming a zigzag pattern. 2. The suction box of claim 1, wherein each segment is substantially straight and disposed at a preselected angle with respect to the preselected direction. (3) The crisp box according to claim 1, wherein the preselected angle is about 45 degrees. (4) In a papermaking machine having a press fabric that is continuously moving in a preselected path in the machine direction to extract water from the whole paper, the suction box
a box body connected to a vacuum source; and a cover secured to the box body, the cover being disposed in the passageway so as to contact the press fabric, the cover applying suction to the press fabric. A suction box having a slot in communication with the box body for removing water from the box body, the slot extending substantially laterally in a zigzag pattern. (5) The suction box of claim 4, wherein the slot includes a plurality of slot segments connected end to end. 6. The suction box of claim 5, wherein each said slot segment is disposed at a preselected angle with respect to said longitudinal direction. (7) The suction box of claim 6, wherein the preselected angle is approximately 45 degrees. (8) The suction box of claim 4, wherein the cover is made of plastic material. (9) The suction box according to claim 4, wherein the cover is made of silicon nitride. (10) The suction box of claim 4, wherein the cover is made primarily of ceramic material.