JP3591374B2 - Canvas or felt cleaning equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a canvas or felt cleaning device used in a dryer part and a press part in a paper machine in a paper mill.
[0002]
[Prior art]
In a paper mill, in order to make paper, first, a pulp suspension of stock is poured from a head box onto an endless belt-shaped wire mesh which is stretched substantially horizontally. Most of the water in the pulp suspension is removed from the mesh by its own weight while running on the wire mesh, or is removed by suction from a foil, wet suction box, wire suction box, etc. . The squeezed pulp suspension is entangled with the fibers in the pulp to form a sheet having a certain shape-retaining force, and is sent to the press part in the next step. In the press part, the pulp sheet is placed on a felt that rotates endlessly, is pressed by a roll, and at the same time, further sucks and squeezes water to form wet paper. The wet paper that has passed through the press part is sent to the next dryer part, where it is pressed alternately on both sides against a number of heating rolls and dried.
[0003]
In the dryer part, the wet paper is inserted between a heated metal roll R and a canvas C indicated by a thick line that rotates while contacting the surface of the metal roll R, as shown in FIG. Dry by contacting the roll R. The canvas C is a cloth in which yarns made of fibers such as synthetic resin fibers are coarsely woven. The wet paper S (indicated by a thin line) is pressed against the heated metal roll R and pressed against the metal roll R. The canvas C also has a role of removing moisture from the back side of the wet paper web S, so that the canvas C is coarsely woven to be rich in air permeability.
Since the canvas C is always in contact with the wet paper web S, a part of the pulp fibers in the wet paper web adhere to the canvas paper, and the permeability gradually decreases. If the permeability of the canvas C is reduced, it is difficult for moisture to escape from the wet paper web S, and the drying efficiency is reduced. Therefore, the canvas C is always provided with high-pressure air or high-pressure water on the surface of the canvas to maintain the air permeability. To remove attached matter such as pulp fibers.
[0004]
FIG. 4 is an explanatory view of a canvas cleaning device used in a paper machine of a paper mill. N is a nozzle for injecting air or high-pressure water onto the surface of the canvas running immediately below the nozzle, and is attached to an endless chain stretched between two chain wheels. Since the endless chain reciprocates in the width direction of the canvas due to the rotation of the chain wheel, the entire surface of the canvas can be cleaned by the injection nozzle of high-pressure air or high-pressure water. The inner diameter of the nozzle tip is usually 3 to 4 mm, and approximately 6 kg / cm ² of air is used.
[0005]
[Problems to be solved by the invention]
However, when producing paper using a large amount of unbeaten pulp, the fibers are not beaten, so that each fiber has little fuzzing and branching, and thus there is little entanglement between the fibers. Therefore, in the state of the wet paper web that has passed through the press part, the proportion of fibers that are not entangled with other fibers or fibers that are weakly entangled is much higher than that of wet paper obtained from beaten pulp.
[0006]
By the way, as shown in FIG. 5, the dryer part of the paper machine has a large number of heated metal rolls R arranged in two upper and lower stages. Are alternately circulated to gradually lose water and dry while the front and back alternately contact the heated metal roll surface. When the wet paper web S transfers from the metal roll R to the next metal roll R, as shown in FIG. 5, the wet paper web S is no longer supported by the canvas C and becomes in a draw state.
[0007]
Since the wet paper web S runs at a high speed, when it is in a draw state, fibers that are not entangled with other fibers on the surface of the wet paper web S or fibers that are weakly entangled separate from the wet paper web surface, and Easy to splatter. The dryer is surrounded at key points so that heat for drying the paper does not escape, and the inside of the dryer is usually at a high temperature of 65 ° C to 90 ° C. The oil to be replenished to the bearings and the like of the type scatters and flies as oil smoke, or adheres to the machine as oil droplets. When these oil smokes or oil droplets are mixed with the fibers to form a lump, when the lump adheres to the canvas C, it is taken into the surface of the wet paper and becomes paper dust, which causes the generation of defective paper. The paper powder as described above can be seen notably in paper that does not use unbeaten pulp.
[0008]
In order to remove these fiber lumps that cause the generation of paper dust, the conventional cleaning device as shown in FIG. 4 has only one air or high-pressure water injection nozzle N, and thus the number of nozzles is insufficient. In addition, since the tip of the nozzle N cannot be brought close to the canvas, high-pressure air or water cannot be sprayed on the canvas surface. Therefore, the cleaning efficiency is low. Because the canvas runs while swinging up and down, if the tip of the nozzle N is brought close to the canvas, the nozzle N contacts the canvas and damages the canvas. Need to keep a certain distance. The cleaning effect by air or high-pressure water jetting is greater as the speed of the jetted air is higher.However, in the conventional apparatus, for the above-described reason, the nozzle tip can be brought closer to the canvas. Air is wasted because it cannot.
[0009]
[Means for Solving the Problems]
Then, in order to solve the above problem, the device shown in FIGS. 1 to 3 has been devised. In the figure, reference numeral 1 denotes a deceleration motor which rotates the crank disk 2 slowly. Reference numeral 3 denotes a crank arm, which is rotatably mounted at a distance r from the center of the crank disk by a pin. Reference numeral 4 denotes a hollow pipe, which is installed so as to intersect with the traveling direction of the canvas C, and has one end connected to an air pipe or a high-pressure water supply pipe. The other end is closed and rotatably fixed to the crank arm. As shown in FIG. 2, a plurality of injection holes P are formed in the bottom of the hollow pipe 4. Reference numeral 5 denotes a guide roll, and the hollow pipe 4 reciprocates along the guide roll 5. Reference numeral 6 denotes a detent that regulates the opening direction of the injection hole P provided in the hollow pipe 4 so as not to change. However, since one end of the hollow pipe is fixed to the crank arm and has a structure that is difficult to rotate, It is not always necessary and is selectively attached.
[0010]
The present invention introduces air or high-pressure water into the hollow pipe 4 and slowly and continuously rotates the deceleration motor 1 so as to reciprocate the hollow pipe 4 in a direction intersecting the running direction of the canvas C. Then, air or high-pressure water is jetted to remove lump or the like of pulp fibers that cause paper dust remaining on the surface of the canvas C by the air or high-pressure water. Normally, since low-cost air is used, the following description is limited to the case where air is used. However, the same effect can be obtained by using high-pressure water instead of air.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention seeks to solve the above-mentioned problems of the prior art with a simple device and low air consumption. Therefore, the injection hole P in the hollow pipe 4 is made smaller than the injection nozzle hole according to the prior art, and of course, the air injection hole is made as close as possible to the canvas C in order to use the used air or efficiently. It is important to inject air with the highest possible pressure toward the canvas.
[0012]
However, if the nozzle having the shape as in the related art is brought too close to the canvas C, the nozzle may come into contact with the canvas C running at a high speed and damage the canvas C. Therefore, in the present invention, the shape of the hollow pipe 4 is a circular pipe, and the outer peripheral surface facing the canvas C is a curved surface. Even when the hollow pipe 4 comes into contact with the canvas C, the canvas C is not damaged. The air injection holes P are provided flush with each other.
[0013]
As a characteristic of the crank mechanism, the piston speed of the hollow pipe 4 connected to the crank arm 3 is determined by the rotation angle α of the pin fixing the crank arm 3 to the crank disk 2 as shown in FIG. 90 ° and 270 ° with respect to the direction of motion of the crank, and the slowest at 0 ° or 180 °. The cleaning effect of the canvas by air is inversely proportional to the speed of movement of the crank. Therefore, the cleaning effect is smallest when the rotation angle α of the crank disk is 90 ° or 270 ° with respect to the movement direction of the crank, as shown in FIG. Great effect. The difference between the maximum value and the minimum value is so large that it cannot be ignored.
[0014]
To prevent the generation of paper dust, it is necessary to obtain a desired cleaning effect in any part of the canvas, so a part having the smallest cleaning effect requires a larger amount of air than other parts. become. It is not impossible to equip a device that adjusts the injection quantity according to the speed of the piston movement of the crank, but it is costly. Even so, a large amount of air is injected as much as the amount injected into the fastest part of the piston movement of the crank, and the air is wasted.
[0015]
Therefore, in the present invention, as shown in FIG. 1, the interval between the air injection holes P is made equal to the distance between the rotation center of the crank disk 2 and the center of the crank pin, that is, the crank radius r. If the interval is smaller than the radius r, a portion of the canvas where air is not injected remains, so it is necessary to at least make the interval smaller than the radius r. When the radius is equal to r, for example, as shown in FIG. When the injection hole of No. 2 moves from α = 0 ° to the position where the speed of the piston movement is the highest, that is, α = 90 ° and 270 °, NO. The cleaning effect of the injection hole 2 is minimized. Subsequently, the camera further moves rightward and reaches α = 180 ° and 360 °. The speed of the piston movement of the second injection hole is the slowest, and the cleaning effect is maximized. At this time, that is, when α = 180 °, NO. No. 2 attached to the left side from the position of the injection hole of No. 2 at a distance r. No. 1 injection hole is also NO. As with the second injection hole, the speed of the piston movement is the slowest, and the cleaning effect is maximized.
[0016]
NO. The position of the canvas at which the cleaning effect of the injection hole of No. 1 is maximized is determined by NO. Since the cleaning effect of the injection hole of No. 2 is the smallest, after all, NO. 1 and NO. With two injection holes, the cleaning effect is averaged. The NO. No. 1 injection hole and NO. Since the phase difference between the two injection holes is 90 °, the cleaning effect at all positions on the canvas can be made substantially uniform.
[0017]
(3) of FIG. No. 1 injection hole and NO. 2 shows a case where the phase difference between the injection holes is 90 ° or less. In this case as well, the cleaning effect can be made uniform to some extent. As is clear from the comparison of the above, the case where the phase difference is 90 °, that is, the mounting interval of the injection holes P is equal to the crank radius r.
The interval between the air injection holes is set to an interval of an integral fraction of the crank radius, such as 1/2, 1/3,. It is also possible to make the air injection amount uniform without changing the total amount of the nozzles. However, as compared with the case where the air injection amount is provided at an interval equal to the crank radius r, further improvement in cleaning efficiency cannot be expected, and the injection hole diameter is reduced. If the size is reduced, the problem of clogging due to dust or the like also occurs. Therefore, when there is no special reason that a crank disk having a particularly large radius must be used, the installation interval should be equal to the crank radius r, and a uniform cleaning effect should be achieved with a minimum number of injection holes.
[0018]
Since the present invention seeks to clean the canvas with the least possible consumption of air, it is desirable that the air to be jetted be jetted onto the canvas surface with as large a pressure as possible. When the spread range of the jetted air is wide, the pressure of the air hitting the canvas surface is small, and the cleaning effect is also small. If the air injection hole is an injection hole opened in the hollow pipe C as shown in FIG. 1, the spread range of the jetted air is inevitably widened, and the pressure of the air blown to the canvas surface is reduced. Therefore, as shown in FIG. 3, a nozzle N that can be adjusted to have a narrower spread range of the jetted air is attached to the hollow pipe C, and the nozzle N is appropriately spaced from the hollow pipe C in order to prevent the nozzle N from coming into contact with the canvas C. A rotatable ball B protruding from the tip is attached. In this way, even when the nozzle N is brought close to the canvas, the tip of the nozzle N can be prevented from contacting the canvas.
[0019]
When the rotatable ball B comes into contact with the canvas C, it slides in either the running direction of the canvas C or the moving direction of the hollow pipe 4, so that even if it comes into contact with the canvas C, the canvas C is damaged. Instead, the speed of the piston movement can be adjusted over a wide range, depending on the situation. The number of the rotatable balls B may be appropriately selected according to the looseness of the hollow pipe and the set distance between the tip of the nozzle N and the canvas C, for example, mounting every 1 to 5 nozzles.
[0020]
For example, when air of 3 kg / cm ² is introduced into the hollow pipe C, the inner diameter of the injection hole P or the nozzle N provided in the hollow pipe C is reduced to about 2 mm, and the distance from the canvas is reduced to about 20 mm. Is about 700 m / min on the canvas surface, and the consumption of air is 0.065 m ³ per piece. If 12 are provided at intervals of 20 cm, the total consumption of air is 1.3 Nm ³ . On the other hand, when air of the same pressure is introduced at a nozzle inner diameter of 3.8 mm by a conventional cleaning device, the air injection speed is about 1000 m / min on the canvas surface, and the air consumption is 1 .2 m ³ , almost the same amount, but it was confirmed that the cleaning effect of the apparatus of the present invention was approximately twice as high.
[0021]
In addition, in the press part of the paper machine, additives such as fibers and pigments, which are weakly entangled with each other, separate from the wet paper and are sucked into the felt, and the felt is clogged. In the prior art, high-pressure water is injected into the felt and discharged from the felt together with the high-pressure water, thereby preventing clogging because the water-squeezing ability is reduced. Since the apparatus of the present invention is an apparatus for cleaning with high-pressure water or air, it can naturally be applied as a cleaning apparatus for felt in a press part, and has the same effect.
[0022]
【The invention's effect】
The apparatus of the present invention can make the injection hole of air or high-pressure water close to the canvas, and blow high-pressure air or water toward the canvas, so that the cleaning effect is higher than that of the conventional cleaning apparatus. Since it is expensive and the equipment is simple, it can be installed at low equipment cost. The invention according to claim 2 is an invention in which the cleaning effect can be made uniform and air or high-pressure water can be used most effectively. The invention according to claims 3 and 4 is an invention in which the cleaning effect is further enhanced by using a nozzle.
[Brief description of the drawings]
FIG. 1 is a front view of a birch screening apparatus of the present invention. FIG. 2 is a back view of a birch screening apparatus of the present invention. FIG. 3 is a front view of a birch screening apparatus of the present invention. FIG. FIG. 5 is a front view of the cleaning device. FIG. 5 is an explanatory view of a dryer part of a paper machine. FIG. 6 is a graph showing a relationship between a rotation angle of a crank disk and a cleaning effect.
DESCRIPTION OF SYMBOLS 1 Deceleration motor 2 Crank disk 3 Crank arm 4 Hollow pipe 5 Guide roll 6 Detent B Rotatable ball C Canvas N Nozzle P Injection hole R Metal roll S Wet paper r Crank radius α Crank disk rotation angle

Claims (2)

An apparatus for cleaning a canvas in a dryer part or a felt part in a press part of a paper machine, comprising a crank mechanism including a crank disk and a crank arm attached to the crank disk, reciprocating in a direction intersecting the running direction of the canvas or felt. The hollow pipe has a curved outer peripheral surface facing the canvas or felt, and nozzles for injecting air or high-pressure water onto the surface of the canvas or felt are attached at a distance smaller than the crank radius. And a rotatable ball protruding from the tip of the nozzle is attached to a key point of the hollow pipe. The apparatus for cleaning a canvas or felt according to claim 1 , wherein the nozzles for injecting air or high-pressure water are attached at a crank radius or at a distance interval that is a fraction of an integer of the crank radius.

Images