JPH0711117B2 - Raw material distributor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a raw material distribution device that can be used in a head box for a papermaking machine.

(Prior Art) An example of a raw material distributing device in a head box that has been conventionally used is shown in FIGS. First, in the example shown in FIG. 5, the raw material is supplied to the header 1 from a direction perpendicular to the paper surface,
It is distributed in the width direction of the head box by the plurality of tubular channels 2. After that, the raw material is ejected from the slicing section 4 through the rectifying section 3.

Further, in the example of FIG. 6, the raw material of the header 5 is similarly distributed by a plurality of distribution pipes 6 and once retained in the rectifying unit 7, and is distributed again through the perforated plate 8 to become a multi-layer flow 9 partitioned by a diaphragm. ,
After being subjected to the paper material dispersing action, they merge and are ejected from the slice section 10.

Normally, a straight pipe is often used as the distribution pipe, but in the case of Fig. 5 and Fig. 6, a device for dispersing the stock material has been devised. The inner diameter is increased, and the distribution pipe shown in FIG. 6 has a conical portion in the middle to widen the flow. These are intended to disperse the stock material by changing the cross-sectional area and to reduce the outlet flow velocity to promote the calming of the flow in the rectifying section.

However, in the case of these distribution pipes or straight pipes,
In all cases, the flow is released all at once at the outlet of the pipe flow path, so the flow velocity distribution is not uniform until the circular flow corresponding to the pipe gradually disappears and disappears, especially in the vicinity of the pipe outlet. A strong vortex is generated around the blowout flow.

In terms of the distribution of stock, the unevenness of concentration in the central part and the peripheral part of the pipeline and the unevenness of the stock dispersion due to the influence of the pipeline wall or the flow velocity distribution remain in concentric circles. However, it has the major drawback that the vortex flow around the jet stream promotes the binding of new paper stock at the same time that the stirring is required, and the stock material is re-bonded when the straightening section is extended until these are eliminated. There is a danger that it will happen, and of course it was difficult to make it smaller.

The same can be said for the multi-layer flow 9 after the perforated plate 8 in FIG. 6. Waves on the wire (streaks) in the flow direction, which is a problem in papermaking, or non-uniformity in the width direction due to paper quality on the product. Sex was often due to these dispensers.

Further, FIG. 7 shows that the distribution pipe 12 arranged in the header 11 becomes a flat flow path 13 from the middle and jets into the chamber 14 to generate a strong vortex flow, aiming to disperse the paper material and make it uniform in the width direction. The flow path 15 is rectified and the raw material is ejected from the slice section 16. With this configuration, it is possible to operate as a paperboard even at a concentration of 2 to 3%, but the strong vortex in the chamber part causes small granular material bundling, which strongly appears on the paper surface that has been made, and is flat. It has a drawback that the paper strength is remarkably lowered, and it is difficult to apply it to general paper.

In the case of a head box for a paper machine, it serves as a raw material distributor (1). Uniform pressure distribution, (2). Uniformization of flow velocity distribution, (3). It can be said that the concentration distribution has been made uniform, and the above items (1) and (2) have improved to a level where there is no practical problem, but rather than being a homogeneous solution, light and shade may occur depending on the flow, or bundling may occur. Due to the paper stock flow, which has the property to do so, the problem of item (3) remains, and sometimes it becomes a big problem in terms of product quality.

As one of the causes of the nonuniformity of the concentration distribution, it is considered that the flow velocity generated at the outlet of the tubular flow channel and the vortex flow around the flow velocity, and the concentric non-uniformity of the concentration, dispersion degree, or fiber cohesion degree caused by these flows.

(Problems to be Solved by the Invention) The present invention intends to solve the above-mentioned problems in product quality in the raw material distributor in the headbox, such as concentric non-uniformity of concentration, dispersity or fiber cohesion. It is what

(Means for Solving the Problems) Therefore, the present invention provides an apparatus for uniformly distributing a raw material flowing in from the lateral direction in the flow direction of the head box,
A plurality of tubular channels are provided, and the outlets of the respective tubular channels have fan-shaped channels that are provided so as to spread in a fan shape in the width direction in a direction substantially at right angles to the outlets, respectively, and have a rectangular cross section in the width direction. A merging portion over the entire width of the shape is provided so that the merging is performed to form a raw material flow over the entire width of the head box. This is a means for solving the problem.

(Operation) At the outlet of each tubular flow channel, a confluent section having a rectangular cross section in the width direction is provided, following the fan-shaped flow channel provided so as to spread in a fan shape in the width direction in a direction substantially perpendicular to the outlet. Since they are provided and merged, the raw material flow collides with one surface of the fan-shaped flow path and spreads radially, and is uniformly distributed in the width direction of the head box without generating a vortex flow that causes uneven concentration or uneven dispersion.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 and FIG. 2 show the embodiment of the present invention, in which a raw material is supplied to a header 21 of a head box 20 from a direction perpendicular to a paper surface. .
The header 21 is provided with a large number of tubular passages 22 for raw material distribution in the width direction of the head box 20, the raw material collides with the upper wall 23 at the outlet of the flow passage 22, and the raw material flows in a fan-like direction in a substantially vertical direction. Road
Guided by 24. The upper wall 23 further extends in the flow direction to the raw material ejection portion. Outlet and upper wall of tubular channel 22
Between the two, the tubular flow path is on the opposite side in the flow direction so that the raw material colliding with the upper wall 23 is guided to the raw material jetting side without stagnating
A spacer 28 having the same shape as that of 22 and having a fan-shaped flow path extending in accordance with the flow is provided.

At the merging portion 25 following the tip of the spacer 28, the adjacent fan-shaped flows merge to form a single flow over the entire width of the head box 20, and the pressure is also uniformized. After that, the raw material passes through the narrowing section 26, is fed to the fiber dispersion section and is ejected from the slicing section 27 in order to further improve the pressure homogenization.

In the raw material distribution tubular flow path 22 configured in this way, the passing raw material collides with an approaching wall instead of the flow path in which the outlet of the tubular flow path 22 is opened, and is further radiated in the regulated fan-shaped flow path 24. Since it gradually spreads and slows down, there is no stagnation, backflow, or vortex generation, and the flow velocity distribution and pressure distribution are stable and uniform. Further, since the influence of the flow direction of the tubular flow channel 22 and the header is canceled by forcing the flow direction to be changed suddenly, the length of the tubular flow channel can be shortened to several times its diameter.

Further, when the raw material moves from the tubular flow path 22 to the fan-shaped flow path 24,
At the same time as it collides with the upper wall 23 and is strongly sheared in the lateral direction, it is decomposed and redistributed so that the flocs (lumps of fiber components) and the non-uniform concentration part of the raw material flow are torn off, and each fan-shaped channel
The distribution of stock in the raw material stream within 24 is greatly improved. Further, since the fiber component is decomposed by the radial spreading flow, the dispersion of the stock material is also improved.

At the confluence point, which is the end of the fan-shaped flow path 24, the flow velocity of each flow path is decelerated, and since the flow velocity component in the same direction is strong, the collision force of the flow at the time of merging is weak, and the pressure and flow can be made uniform. The length in the flow direction of the merging portion 25 is also greatly reduced. In addition, since the distribution and dispersibility of the stock material in each fan-shaped flow path 24 are made uniform, the merging on this surface is performed quickly.

Further, due to these effects, if there is a stock material dispersion flow channel having a relatively large pressure loss on the downstream side of the merging portion, the merging portion may be allowed to function as it is as an inlet of the continuous flow passage. If the flow passage thickness is reduced and a throttling action is applied, a highly uniform paper stock flow in terms of pressure / flow velocity distribution can be supplied to the downstream side. 3 and 4 show an example in which the distribution pipe and the fan-shaped flow path 24 are made into two surfaces. Further, the fan-shaped flow passage shown in FIG. 1 can be applied to a multi-layered head box by making it multi-stage.

(Effects of the Invention) As described in detail above, according to the present invention, a fan-shaped flow path is provided at the outlet of each tubular flow path so as to spread in a fan shape in a direction substantially perpendicular to the outlet and in the width direction. By decelerating the flow in a accelerating manner on the road and then merging, the differences in the concentration, the degree of dispersion, and the flow velocity distribution generated in the tubular flow path are made uniform. Further, the flow passage area changes continuously from the distribution pipe to the raw material merging portion, and there is no stagnation or vortex of the raw material, and the uniformity of the raw material properties is maintained. In addition, the flow path is less likely to get dirty and maintenance is easier. Furthermore, the flow path from the distribution pipe to the confluence has a shape with a long peripheral length with respect to the cross-sectional area and a shallow liquid surface depth. Therefore, the flow path itself has a strong effect of dispersing the stock material, and it is possible to obtain a paper with a good texture.

Therefore, over the entire width of the head box, a uniform raw material flow that is greatly improved in terms of stock properties can be created, and for the same reason, a stable and uniform flow can be achieved in terms of pressure distribution and flow velocity distribution. Therefore, by using the distributor of the present invention, streak on the wire and non-uniformity in the width direction on the paper quality can be greatly improved in the papermaking process, and a raw material having a higher concentration can be dealt with. Further, in terms of the headbox configuration, the conventional distributor can be greatly miniaturized, and it is possible to produce the one which is low in cost and excellent in performance.

[Brief description of drawings]

1 and 3 are side sectional views of a head box equipped with a raw material distributing apparatus showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line ZZ in FIG. 1, and FIG. 4 is shown in FIG. YY sectional view, fifth
FIGS. 6, 6 and 7 are side sectional views of a head box showing an example of a conventional distributor, and FIG. 8 is a sectional view taken along line X-X of FIG. Explanation of the main parts of the figure 22 …… Tubular flow path for raw material distribution 23 …… Upper wall 24 …… Fan flow path 25 …… Merging part 28 …… Spacer

Claims (1)

[Claims] 1. A device for uniformly distributing a raw material flowing in from a lateral direction in a flow direction of a head box, wherein a plurality of tubular channels are provided, and outlets of the respective tubular channels are respectively provided with a direction substantially perpendicular thereto. In addition, following the fan-shaped flow path provided so as to spread in a fan shape in the width direction, a merging portion having a rectangular cross-section in the width direction and having a rectangular cross-section is provided so that the raw material flows over the entire width of the head box. Raw material distribution device.