JPH0223636B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is aimed at reducing the amount of mist that is scattered at various locations when cutting wet paper paper by jetting high-pressure water from a cutting nozzle in the wire part of the paper making process. The present invention relates to a method for preventing scum from adhering to a nozzle cut, which prevents scum from adhering to a nozzle cut and causing paper breakage or other problems, and an apparatus for carrying out the method.

[Conventional technology]

During the papermaking process, the paper stock dispersion supplied from the head box slice to the wire part is subjected to the vacuum dehydration action of the suction box and suction couch roll as it travels through the wire part, and becomes wet paper with a density of approximately 20%. It is ejected from cutting nozzles (also called trim nozzles, with a diameter of about 0.3 to 0.6 mmφ) located on both sides of the rear part of the wire part to match the predetermined cutting width (this position is called the nozzle cut position). The paper is cut to a predetermined width using high-pressure water (15 to 20 kg/cm ² ).
Both sides cut by the nozzle in this way fall into the couch pit, and only the remaining wet paper, which has reached the predetermined paper width, is transferred downstream by the suction action of the pick-up roll and sequentially passes through the press part, dryer part, and calender part. It is wound onto a reel and becomes a product.

The nozzle cut in the wire part is the most important part in the paper making process, and if the cutting condition is poor, the part will often become damaged and result in paper breakage. Therefore, in order to improve the cutting condition, two cutting nozzles are placed one on top of the other in the direction of wire movement (called double cutting) to eliminate uncut edges, or one of the two nozzles is Place the other nozzle at the cut position, and cut the other nozzle on the outside (the cut between the two cutting nozzles is called the selvage part, and this cutting is called the selvage cut) to raise the selvage. The wet paper in the center is transferred to the downstream side by a pick-up roll and dropped from the center roll to the couch pitch (this is called selvage) to improve the cutting condition. It was not uncommon for two or three cutting nozzles to be used on just one side, sometimes in combination with the above.

[Problem that the invention seeks to solve]

As mentioned above, in a nozzle cut, high-pressure water is ejected from the cutting nozzle and violently collides with the wet paper to cut it, so fine particles of paper stock become mist and scatter around the paper, causing various problems such as: I was awake.

In other words, a part of this mist adheres to the cutting nozzle, enlarges over time, hangs from the tip of the cutting nozzle, and finally falls to the nozzle cut position of the wet paper on the wire, causing poor cutting. This will result in a paper break. In addition, the scattered mist is flowed in the direction of movement of the wire and may adhere to the cut nozzle on the downstream side or the pick-up felt of the pick-up roll, contaminating it and weakening the suction force of the pick-up roll. Dirt transfers to downstream rolls and accumulates over time.
It turns into lees and causes paper breakage and product stains. Among the above-mentioned problems, it was particularly necessary to avoid the adhesion of lees to the cutting nozzle, since this can cause serious effects such as paper breakage. This has become increasingly common when using multiple cutting nozzles. Therefore, workers had to constantly go around and check the adhesion of lees to the cutting nozzle and the cutting condition, which required a lot of manpower. However, it was still difficult to completely prevent problems, and conventional nozzle cutting Although there were various problems as described above, there was no effective countermeasure against them.

[Means for solving problems]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for preventing sludge adhesion to a nozzle cut, which solves the problems of the prior art described above and prevents mist generated during nozzle cut from causing various problems. In other words, one aspect of the present invention is that when high-pressure water is jetted from the cutting nozzle to cut both sides of the wet paper on the wire at the rear of the wire part, the generated mist is removed by suction installed near the cutting nozzle. This invention relates to a method for preventing sludge adhesion to a nozzle cut, which is characterized in that the suction is carried out by a suction device, and the water is discharged together with water injected into the base of the suction device into a reduced pressure chamber connected to the suction device.

Another aspect of the present invention is that the cutting nozzle is installed near the cutting nozzle at the rear of the wire part,
A suction device has a tip opening for sucking in mist generated when high-pressure water is jetted from the cutting nozzle to cut the wet paper on the wire, the rear end of which is connected to a decompression chamber, and the suction device This invention relates to a nozzle cut sludge adhesion prevention device characterized in that a water injection pipe is attached to the base of the nozzle cut.

[Explanation of configuration]

In the method of the present invention, when high-pressure water is jetted from the cutting nozzle to cut both sides of the wet paper web on the wire at the rear of the wire part, the suction installed near the cutting nozzle is used to prevent the generated mist from scattering. However, if you only suction the mist, it will stick to the pipe wall of the suction path and block it, so you can inject it into the base of the suction device and let the mist flow with the water. By discharging the mist into the connected vacuum chamber, it is possible to continue suctioning and discharging the mist without any problems. The degree of decompression for suction is -100 to -
Approximately 400 mmHg is sufficient, and should be adjusted depending on the amount of injection and the amount of mist generated. A special vacuum chamber that provides such a suction device and serves as a discharge site for mist and water may be provided, but known vacuum chambers such as wire part suction box vacuum chambers (-100 to -150 mmHg) or Decompression chamber of suction couch roll (-400 to -500mm at high vacuum section)
Hg, -200 to -250 mmHg at the lower back area), etc. may be used.

Next, an apparatus of the present invention suitable for carrying out the method of the present invention will be explained with reference to the drawings.

Fig. 1 is a front explanatory view showing an example of a set in which the positional relationship between the device of the present invention and a cutting nozzle is fixed, and it is installed and used, and Fig. 2 is one of the sets shown in Fig. 1. Regarding the above usage mode, A is a perspective view schematically showing the whole including both sides, B and C are perspective views schematically showing the main parts of only one side, and Fig. 3 shows the device of the present invention being fixed in position independently of the cutting nozzle. It is a perspective explanatory view showing the installed state.

In the drawings, reference numeral 1 denotes an apparatus of the present invention, which sucks the mist M generated when the wet paper web S is cut by the cutting nozzle 7 in the following manner. That is,
As shown in FIG. 1, a high-pressure water pipe 8 is attached to the cutting nozzle 7, and when this high-pressure water is ejected from the cutting nozzle 7 at the nozzle cut position, the wet paper web S on the wire 10 is cut. However, at this time, a large amount of mist M is generated. In the device 1 of the present invention, a suction device 2 having a tip opening 2a for sucking in the mist M generated in this way has a rear end connected to a vacuum chamber 5 (a suction couch roll 11 in FIG. 1) via a suction pipe 4. In FIG. 3, a suction box 12 is utilized), and an injection tube 6 is attached to the base of the suction device 2. The suction pipe 4 and the injection pipe 6 are provided with control valves 4a and 6a, respectively.

In the device 1 of the present invention having such a structure, the suction device 2, which is the main part, is located near the cutting nozzle 7 at the rear part of the wire part, that is, at the nozzle cut position, preferably near the cutting nozzle 7 as shown in FIG. It is installed outside (on the side) of the cutting nozzle 7, and preferably so that the tip opening 2a is at a height between the height of the cutting nozzle 7 and the wet paper web S. Furthermore, as shown in FIG. 1, the upper end of the tip opening 2a of the suction device 2 is set at approximately the same height as the tip of the cutting nozzle 7, and the angle θ between the tip opening 2a, the opening surface, and the vertical direction is set to 20 to 30. It is preferable to set the angle to .degree. in order to suck the mist M that scatters around the cutting nozzle 7. The shape of the suction device 2 may be such that the diameter increases toward the tip as shown in the figure, or the diameter may be the same.

In this case, there are two aspects of the positional relationship between the suction device 2 and the cutting nozzle 7. One is a mode in which the positional relationship of the suction device 2 with respect to the cutting nozzle 7 is fixed as shown in FIG. In the case of FIG. 1, the positional relationship is fixed by providing a support 3 on the suction device 2 and fixing the support 3 to the base of the cutting nozzle 7. In addition, as shown in FIG. 1, the support column 3 is divided into two parts, upper and lower, with an overlapping part.
The upper end of the support 3 is slidably fitted to the horizontal base of the cutting nozzle 7 and can be moved horizontally by loosening the screw 3c. To,
Preferably, each fixed position can be adjusted. Generally, the cutting nozzle 7 is moved in the width direction of the wire 10 by a cutting nozzle moving device 9 as shown in FIG. When the device 2 is fixed in position with the cutting nozzle 7, the suction device 2 also moves as the cutting nozzle 7 moves, so there is no need to adjust the position of the suction device 2 again.

Another aspect of the positional relationship between the aspirator 2 and the cutting nozzle 7 is when the aspirator 2 is fixed in position independently of the cutting nozzle 7 as shown in FIG. (not shown). In this case as well, the installation position of the suction device 2 remains the same as the above-mentioned preferred embodiment in the vicinity of the cutting nozzle 7. Therefore, in this case, as for the position of the suction device 2 in the width direction of the wire 10, it is preferable to fix the position of the suction device 2 in consideration of the position of the cutting nozzle 7 when performing nozzle cutting with the paper width W at the maximum.

The device 1 of the present invention is used in combination with a cutting nozzle 7. The number of combinations is not necessarily 1:1; for example, as shown in FIG. 3, one of the former may be combined with the latter two. However, in a device in which the device 1 of the present invention and the cutting nozzle 7 have a fixed positional relationship, it is convenient to use a device in which each of these devices constitutes a set (referred to as a cutting section). . This set of cutting portions corresponds to one conventional cutting nozzle. Therefore, a plurality of sets of cutting parts are used in place of the cutting nozzle when the double cut in the conventional nozzle cut is raised. In Fig. 2 A, one set of cutting units are installed for cutting each side Sa of the wet paper web S, but in B, two sets are installed for double cutting, and in C, two sets are installed for cutting the edges up. A cut portion is provided for cutting each side portion Sa. 2 used for double cut
The cut part of the set is connected to the wire 1 as shown in Figure 2B.
It is preferable to fix the positional relationship and integrate them so that they are aligned in a straight line in the traveling direction of 0.

[Action and effect]

The control valves 4a and 6a of the suction pipe 4 and water injection pipe 6 of the apparatus 1 of the present invention are opened to put the suction device 2 into a state of suction and water injection, and the cutting nozzle 7 is operated to
If the cutter is cut, the generated mist M will be sucked into the suction device 2 without scattering, and will be flushed away with water and discharged into the decompression chamber 5, so that the mist M will not adhere to the cutting nozzle 7 or other parts. When the suction device 2 is located outside the cutting nozzle 7, all of the generated mist M is directed outside, so there is no risk of the mist M adhering to and contaminating at least the part that will become the product. The degree of suction and the amount of water injected are adjusted according to the amount of mist M generated using control valves 4a and 6a. In this way, according to the present invention, the mist M generated in the nozzle cut
By suctioning and discharging the paper without causing any scattering, there is no accumulation of lees, and paper breakage and stains caused by mist M can be completely eliminated, which greatly contributes to the stable operation of papermaking.

[Brief explanation of drawings]

Fig. 1 is a front explanatory view showing an example of a set in which the positional relationship between the device of the present invention and a cutting nozzle is fixed and is installed and used, and Fig. 2 shows one or more of the sets shown in Fig. 1. Regarding the usage mode, A is a perspective view schematically showing the whole including both sides, B and C are perspective views schematically showing the main parts of only one side, and Fig. 3 is a perspective view showing the device of the present invention installed in a fixed position independently of the cutting nozzle. FIG. DESCRIPTION OF SYMBOLS 1... Device of the present invention, 2... Aspirator, 2a... Tip opening, 3... Support column, 3a... Long hole, 3b... Screw, 3c...
Screw, 4...Suction piping, 4a...Control valve, 5...Decompression chamber, 6...Water injection pipe, 6a...Control valve, 7...Cut nozzle, 8...High pressure water piping, 9...Cut nozzle moving device, 10...Wire , 11... suction couch roll, 12... suction box, S... wet paper,
Sa…side, M…mist.

Claims (1)

[Claims] 1. When cutting both sides of the wet paper web on the wire at the rear of the wire part by jetting high-pressure water from the cutting nozzle, the generated mist is collected using a suction device installed near the cutting nozzle. A method for preventing dregs from adhering to a nozzle cut, which comprises suctioning the suction device and discharging it together with water injected into the base of the suction device into a reduced pressure chamber to which the suction device is connected. 2. It is installed near the cutting nozzle 7 at the rear of the wire part, and is used to suck in the mist M generated when cutting the wet paper web S on the wire 10 by spouting high-pressure water from the cutting nozzle 7. A nozzle cut dregs adhesion prevention device characterized in that an aspirator 2 having a tip opening 2a has its rear end connected to a decompression chamber 5 and a water injection pipe 6 is attached to the base of the aspirator 2. 3. The nozzle cut lees adhesion prevention device according to claim 2, wherein the suction device 2 is installed outside the cut nozzle 7. 4. The nozzle cut lees adhesion prevention device according to claim 2 or 3, wherein the suction device 2 is installed in a fixed position relative to the cutting nozzle 7 and is movable together with the cutting nozzle 7. 5. The nozzle cut dregs adhesion prevention device according to claim 2 or 3, wherein the suction device 2 is installed in a fixed position independently of the cut nozzle 7.