JPH0611953B2 - Formation improvement device of twin wire type paper machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for improving formation of a papermaking machine in a twin-wire type paper machine that sandwiches a paper raw material between upper and lower wires for papermaking. .

(Prior Art) FIG. 3 shows an example of a conventional twin-wire homer, which is said to have good fiber dispersion and therefore good paper formation. The paper raw material liquid 2 ejected from the head box 1 lands on the lower wire 3 to form a forming board 4, a plurality of foils 5,
Dehydration is performed in the vacuum foil box 6 or the like, and the raw material concentration gradually increases. Furthermore, the raw material is top unit 1
An upper wire 19 whose traveling direction is reversed by a top lead-in roll 8 of 8 is sandwiched between the upper and lower wires 19 and 3 on the lead-in box 9.

The sandwiched raw material is dehydrated by the pressing pressure generated by the wire tension of the upper wire 19 on the plurality of installed shoes 10. Push-in roll 11
After the dehydration progresses by, the transfer suction box 13 rides on the lower wire 3, and the wet paper dehydrated by the suction box 14 and the suction couch roll 15 is picked up by the suction pickup roll 16 and transferred to the next pressing step. It The upper wire 19 and the lower wire 3 are endless, respectively, and are turned and washed by the wire turning rolls 12 and 17 to prepare for the next dehydration.

By the way, according to the research conducted by the present inventors, the formation in this type of twin homer shows that the pressure gradient of the pressure pulse generated in the raw material by the portion where the raw material is sandwiched by the two wires and the pressing pressure after the sandwiching is performed. (Hereinafter referred to as a pressure gradient) has a great influence, and if the pressure gradient is made appropriate, the raw material liquid is decelerated and accelerated in the traveling direction without stirring, and the formation can be greatly improved. I found it. The pressure gradient for decelerating and accelerating is the machine speed, basis weight, raw material blending, concentration in that state, etc.
It is called operating condition. ) Changes the appropriate value.

FIG. 4 is an enlarged view of the portion of the shoe 10 described above. Conventionally, as shown in the figure, the shoe 10 is composed of a shoe body 20 and a supporting body 21 thereof. Since the radius of curvature of the arc formed by the wire guide surface consisting of the shoe body 20 is always constant, the pressing pressure P is the wire tension T determined by P = T / R (T: wire tension, R: radius of curvature). Adjust and push pressure P
Was set to a predetermined pressure. However, there is a limit to the adjustment of the wire tension, and since the radius of curvature of the wire guide surface formed by the shoe main body 20 is constant as described above, when the operating conditions change due to changing the paper material, the pressure gradient described above is changed. Was out of the appropriate value range, and the texture tended to deteriorate.

(Problems to be Solved by the Invention) As described above, in the wire part of the conventional twin-wire paper machine, since the radius of curvature of the wire guide surface formed by the plurality of shoes is constant, operating conditions are However, there was a problem that an appropriate pressure gradient could not be set when there was a change, and the formation was deteriorated.

The present invention has been made in view of this point, and an object of the present invention is to provide a device that can always set an appropriate pressure gradient and can significantly improve the formation.

(Means for Solving Problems) For this reason, the present invention is a formation improving device installed in a wire part of a twin wire type paper machine in which a papermaking raw material travels while being sandwiched between two wires. Each shoe blade and a blade moving device that is connected to each of the shoe blades and moves the shoe blades in the radial direction by fluid pressure are provided, and the radius of curvature of the arc of the shoe blades can be arbitrarily changed during operation. This is a means for solving the problem.

(Operation) The curvature of the wire guide surface formed by a plurality of shoes can be arbitrarily changed wholly or partially so that the pressure gradient between the two wires, which changes depending on operating conditions, is always maintained at an appropriate value. .

(Example) Hereinafter, the Example of this invention is described based on drawing.

FIG. 1 is a partially omitted sectional view showing the entire structure of the shoe portion according to this embodiment. The parts other than those shown in the figure are the same as those of the conventional device shown in FIG.

In FIG. 1, reference numeral 21 designates a support disposed near the confluence of the two upper and lower wires 26 and on the downstream side.
1 has an upper surface formed with an appropriate curvature, and a plurality of shoe blades 23 are arranged on the upper surface in parallel in the width direction of both wires 26. As shown in FIG. 2, the shoe blade 23 is supported by a bracket 25 in which a blade moving device 24 such as a pneumatic / hydraulic cylinder or a flexible tube is housed. The lower portion of the bracket 25 is fitted and fixed to the upper surface of the support 21.

If the protrusion amount of each of the plurality of shoe blades 23 is individually changed by the blade moving device and the curvature of the wire guide surface formed by the shoe blades 23 is changed, the wrap angle of the upper and lower wires is also changed. Become. In order to adjust the wrap angle, a pushing roll 27 that is movable up and down and back and forth is arranged on the downstream side of the plurality of shoe blades 23.

In the present embodiment having the above-described configuration, when the operating conditions change, each shoe blade 23 is independently moved in the radial direction to change the radius of curvature of the arc formed by the plurality of shoe blades 23. The pressure gradient between the two wires is maintained at an appropriate value. The blade moving device 24 including an air cylinder, a hydraulic cylinder, a flexible tube, and the like is attached to each shoe blade 23. Therefore, by adjusting the pressure supplied to each shoe blade 23, the respective shoe blades 23 move in the radial direction. The radius of curvature of the arc formed can be set arbitrarily. Since the supply pressure can be adjusted externally, the following can be done even during operation.

(1) The radius of curvature of an arc formed by a plurality of shoe blades can be set arbitrarily.

(2) It is possible to combine the curvatures of arcs formed by a plurality of shoe blades.

(3) The pitch of the shoe blade can be set arbitrarily.

In this embodiment, the raw material concentration in the wire part is 0.8 to 3.5.
%, The radius of curvature R of an arc formed by a plurality of shoe blades is 1 to 5 m, and the wire tension T is preferably 10 to 30 PCI.
Even if the operating conditions change, the pressure gradient between the two wires can be maintained at an appropriate value at all times, and a good condition can be maintained.

Although the plurality of blade moving devices operate individually, they are managed by a control device (not shown) so that they can be totally controlled, and even if the operating conditions change during normal operation. It is also possible to follow immediately.

(Effect of the invention) As described in detail above, the present invention is provided with the blade moving device that is connected to each of the plurality of shoe blades and moves the shoe blades in the radial direction by fluid pressure.
The radius of curvature of the arc of the shoe blade can be arbitrarily changed from the outside during operation, and it is possible to always set the pressure gradient at the drainage part of the wire part to an optimum value, further improving the texture of papermaking. -It can be improved. Further, since the present invention uses the shoe blade, the pitch of dehydration pressure pulse, the number and the magnitude of the pressure pulse can be arbitrarily controlled, and since it is a pressure regulation, the controllability associated with the change of the paper or the paper speed is controlled. It is good and can be applied in a wide range. Moreover, since the control is performed by the fluid pressure, the control operation can be performed from the outside of the device.

Conventionally, by changing the position of the table roll with respect to the wire traveling portion, a dehydrator for a paper machine that changes the curvature of the wire traveling portion has been proposed in Japanese Utility Model Publication No. Sho 48-29101. Since the table roll is a rotating roll, it cannot be a small-diameter roll due to the bending of the roll. Therefore, the pitch between rolls is limited, the pitch and the number of dehydration pressure pulses applied to the papermaking raw material are constant, and the radius of curvature can be arbitrarily changed by adjusting the position of the shoe blade by the fluid pressure as in the present invention. I can't do that.

Further, the movement of the table roll of the above-mentioned conventional apparatus is performed by turning the screw one by one, and therefore it cannot be arbitrarily performed during operation from the outside as in the present invention, and it is necessary to enter the machine and turn the screw. , It is very dangerous to carry out while driving.

[Brief description of drawings]

FIG. 1 is a partially omitted sectional view of a formation improving apparatus showing an embodiment of the present invention, FIG. 2 is a sectional view showing a supporting structure of a shoe blade alone of the apparatus, and FIG. 3 is a twin wire type machine wire. FIG. 4 is a schematic side view of the part, and FIG. 4 is a sectional view showing a conventional shoe. Description of the main parts of the figure 21 …… Support 23 …… Shoe blade 24 …… Blade moving device

Claims (1)

[Claims] 1. A formation improving device installed in a wire part of a twin-wire type paper machine in which a papermaking raw material travels while being sandwiched between two wires, the plurality of shoe blades and each of the shoe blades. And a blade moving device for moving the shoe blade in the radial direction by fluid pressure, and the radius of curvature of the arc of the shoe blade can be arbitrarily changed during operation. Formation improvement device.