JPH11140725A - Pulp opening for absorptive form and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for pulp opening and an apparatus therefor, designed to stably feed pulp in a compressed state onto the opening surface of the outer circumference of an opening cylinder 7 under rotation in opening the pulp for absorptive forms. SOLUTION: This method comprises the following mechanism: bifurcated pulp feed paths 10A, 10B are provided, where pulp is compressed in the direction of the paths by the aid of pistons 12A, 12B alternately plunging into the paths, respectively, and fed onto an opening cylinder 7. Respective inlet sides of the paths 10A, 10B are equipped with change-over valves 13A, 13B, while the respective outlet sides with openable stoppers 14A, 14B, and the pulp is compressed through the co-operation of the pistons 12A, 12B when the stoppers are closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an absorbent used for sanitary goods such as sanitary napkins and disposable diapers.
The present invention relates to an absorbent pulp defibration method and apparatus for defibrating pulp, which is a main raw material of an absorbent.

[0002]

2. Description of the Related Art In the manufacture of this type of absorbent, generally, in a defibrating device, pulp is supplied to a defibrating surface on the outer periphery of a rotating defibrating cylinder by a pulp supply passage, and the pulp is defibrated. I do. And in the stacking device,
The defibrated pulp is piled into an appropriate shape to obtain a desired absorbent (see JP-A-8-337954).

In the defibrating device, pulp P is supplied to a defibrating cylinder 100 as shown in FIG. That is, a pair of side belts (lattice belts) 1
Pulp (pulp roughly defibrated from pulp rolls by a defibrating machine) P is stored in a popper section 101 formed by the side belts 101A and 101B.
The pulp P is fed downward by the feed motion of the pulp P, and the pulp P is fed further downward by the feed motion of the two pairs of rollers 102A, 102B, 103A, 103B, and the defibration surface on the outer periphery of the rotating defibration cylinder 100. It is supplied so as to be pressed against.

[0004]

However, air is trapped between the pulp in the popper part, and the above-mentioned feeding movement from the side by the belt or the roller alone is not sufficient.
The pulp cannot be pressed sufficiently against the defibrating cylinder when the air cannot be released and the pulp is sufficiently compressed, that is, with the air removed, and the supply of pulp to the defibrating cylinder is stable due to the air. do not do. And, the instability of the pulp supply amount to the defibrating cylinder causes the defibration amount of the pulp to vary, and in the subsequent fiber-laying operation, the thickness and the density of the absorbers vary.

The present invention has been made in view of the above problems, and has as its object to provide a pulp defibration method and apparatus for an absorber that can stably supply pulp to a defibration cylinder in a compressed state. I do.

[0006]

Therefore, in the invention according to claim 1, pulp is supplied to the defibrating surface on the outer periphery of the rotating defibrating cylinder by the pulp supply passage, and the pulp is defibrated. In this case, there is provided a pulp defibration method for an absorbent body, wherein pulp is compressed in the direction of the pulp supply passage by a piston which enters the pulp supply passage from outside the pulp supply passage.

[0007] The invention according to claim 2 is characterized in that the pulp supply passage is branched into a plurality of passages, and the pulp is compressed by the piston alternately in each passage. The invention according to claim 3 is characterized in that the supply of pulp from the upstream side is switched at the branch of the pulp supply passage. The invention according to claim 4 is characterized in that the outlet side of the pulp supply passage downstream of the piston is opened and closed by a stopper, and the pulp is compressed in cooperation with the piston when closed.

The invention according to claim 5 is characterized in that the compressed state of the pulp is detected, and the operation of the piston is controlled based on the detected state. On the other hand, in the invention according to claim 6, in the pulp defibrating device for an absorber, which supplies pulp toward the defibrating surface on the outer periphery of the rotating defibrating cylinder by the pulp supply passage and defibrates the pulp, From outside the supply passage,
Disclosed is a pulp defibrating device for an absorbent body, wherein a piston that protrudes into a pulp supply passage and compresses pulp in the direction of the passage is provided.

[0009] The invention according to claim 7 is characterized in that the pulp supply passage is branched into a plurality of sections, and a piston is provided in each of the branches. The invention according to claim 8 is characterized in that a switching valve is provided at a branch portion of the pulp supply passage. Claim 9
In the invention according to the invention, an outlet side of the pulp supply passage downstream of the piston can be opened and closed, and a stopper for compressing the pulp in cooperation with the piston when closed is provided.

The invention according to claim 10 is characterized in that a sensor for detecting the compression state of the pulp is provided, and a control circuit for controlling the operation of the piston based on a signal from the sensor is provided.

[0011]

According to the first or sixth aspect of the present invention, the pulp is compressed in the pulp supply passage in the direction of the passage by the piston, so that the pulp is sufficiently compressed to release the air in a state where the air is removed. The pulp can be supplied to the defibration cylinder and the pulp supply amount to the defibration cylinder can be stabilized. Therefore, the defibration amount of the pulp is stabilized, and the thickness and density of the absorber can be stabilized in the subsequent fiber stacking operation.

According to the second or seventh aspect of the present invention, the pulp can be alternately compressed by the piston in the plurality of pulp supply passages, and the efficiency can be improved. According to the invention according to claim 3 or claim 8, by switching the supply of pulp from the upstream side to the plurality of pulp supply passages, efficiency can be further improved. Claim 4
According to the ninth aspect, the outlet side of the pulp supply passage is opened and closed by the stopper, and the pulp is compressed in cooperation with the piston when the pulp supply passage is closed, so that the compression ratio can be increased.

According to the fifth or tenth aspect of the present invention, the controllability is improved, for example, by detecting the compressed state of the pulp and controlling the operation of the piston based on the detected state. I do.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of an absorber manufacturing apparatus including the pulp defibrating device for an absorber according to the present invention.
In FIG. 1, reference numeral 6 denotes a defibrating device, the upper part of which is in communication with the pulp circulation passages 4, 5. Pulp circulation passages 4, 5
As shown in FIG. 2, the pulp P drawn out from the pulp roll 1 is coarsely defibrated by the defibrating machine 2 and stored in the stock bin 3, sent out from the supply-side pulp circulation passage 4 to the defibrating device 6, and The amount is returned from the return-side pulp circulation passage 5 to the stock bin 3.

The defibrating device 6 has a defibrating cylinder 7 which rotates around a horizontal rotation axis at the lowermost part. As shown in FIG. 3, a large number of small projections (teeth) are provided on the outer periphery of the defibrating cylinder 7 to form a defibrating surface. Defibrating device 6
Also, a pair of side belts (lattice belts) 8A and 8B forming a popper portion 8 connected to the pulp circulation passages 4 and 5 at the uppermost portion, and a pair of side belts forming a straight pressure feeding passage 9 below the hopper portion 8. Side belt 9A, 9B
And pulp supply passages 10A and 10B that are connected to the lower side of the pressure feed passage 9 and branch into two to supply pulp to the defibration surface on the outer periphery of the defibration cylinder 7.

Each of the pulp supply passages 10A and 10B is symmetrically provided in a "U" shape, and the upstream side forms a pulp guide section and the downstream side forms a pulp compression section (piston sliding section).
Servo motors 11A, 11A are provided in the pulp compression sections on the downstream side of the pulp supply passages 10A, 10B, respectively.
Pistons 12A and 12B driven by B are provided so as to protrude into the passage from a retreat position outside the passage and move in the passage direction.

Electromagnetically driven switching valves 13A and 13B for opening and closing the inlets are provided at the inlets (branches) of the pulp supply passages 10A and 10B. The outlet side of each pulp supply passage 10A, 10B (the defibration cylinder 7
Side), an electromagnetically driven stopper 14 for opening and closing the outlet side
A and 14B are provided. Also, the piston 12A,
Pressure sensors 15A and 15B are provided on the top surface of 12B to detect the compressed state of the pulp.

The signals from the pressure sensors 15A and 15B are input to a control circuit (not shown), which controls the servomotors 11 for driving the pistons 12A and 12B.
A, 11B, switching valves 13A, 13B, and stopper 14
A, 14B are controlled. Next, the operation of the defibrating device 6 will be described with reference to the time chart of FIG.

A pair of side belts 8A of the hopper section 8,
8B and a pair of side belts 9 in the pressure feeding passage 9.
The pulp P is pressure-fed to the pulp supply passages 10A and 10B by the feeding motions of A and 9B. In one pulp supply passage 10A, with the piston 12A retracted, the switching valve 13A on the inlet side is opened and the stopper 14 on the outlet side is opened.
A is closed, whereby the pulp P is fed and stored in the pulp supply passage 10A (the state of FIG. 1).

At this time, in the other pulp supply passage 10B, the switching valve 13B on the inlet side is closed and the stopper 14B on the outlet side is opened. 7 while being pressed (state of FIG. 1). Next, in one pulp supply passage 10A, the switching valve 13A on the inlet side is closed,
When the piston 12A starts descending, the pulp supply passage 10
The pulp P in A is compressed by cooperation with the stopper 14A (the state of FIG. 5). In this compression process, the pressure sensor 15A
The compression state of the pulp P is monitored, and when the pressure becomes equal to or higher than a predetermined compression pressure, the piston 12A is temporarily stopped to make the compression state uniform.

At this time, in the other pulp supply passage 10B, the compressed pulp P is supplied while being pressed against the defibrating cylinder 7 by the further lowering of the piston 12B (the state of FIG. 5). Next, one pulp supply passage 10A
, The outlet side stopper 14A is opened and the piston 1
By the lowering of 2A, the supply of the compressed pulp P is started while being pressed against the defibrating cylinder 7.

At this time, in the other pulp supply passage 10B, after the piston 12B returns to the retracted position, the switching valve 13B on the inlet side opens and the stopper 14B on the outlet side closes. The pulp P is sent to and stored. Next, in one pulp supply passage 10A, the piston 12A is further lowered,
The compressed pulp P is continuously supplied while being pressed against the defibrating cylinder 7.

At this time, in the other pulp supply passage 10B, the switching valve 13B on the inlet side is closed, the piston 12B starts descending, and the pulp P in the pulp supply passage 10B is compressed in cooperation with the stopper 14B. . In this compression process, the compression state of the pulp P is monitored by the pressure sensor 15B, and when the compression pressure becomes equal to or higher than a predetermined compression pressure, the piston 12B is temporarily stopped to make the compression state uniform.

Next, in one pulp supply passage 10A, after the piston 12A returns to the retracted position, the inlet-side switching valve 13A opens and the outlet-side stopper 14A closes, whereby the pulp supply passage 10A is closed. The pulp P is sent to and stored. At this time, in the other pulp supply passage 10B, the outlet side stopper 14B is opened, and the supply of the compressed pulp P is started while being pressed against the defibrating cylinder 7 by the lowering of the piston 12B.

By repeating such an operation, the pulp P can be supplied to the defibrating cylinder 7 in a state where the pulp P is sufficiently compressed and air is removed, and the pulp supply amount to the defibrating cylinder 7 is stabilized. In the defibrating cylinder 6, the pulp P stably supplied in the compressed state is defibrated in this manner, whereby the defibrated amount of pulp can be stabilized.

In order to detect the compressed state of the pulp,
Although the pressure sensors 15A and 15B are used, the compression state of the pulp may be detected by detecting a load applied to the servomotors 11A and 11B for operating the piston. The pressure sensors 15A and 15B are
It may be provided on the stoppers 14A, 14B side instead of the A, 12B side.

Next, the structure and operation of the fiber stacking device 20 provided below the fiber opening device 6 will be described. Stacking device 20
Is configured to include a base conveyor 21 and a pattern drum 25. The base conveyor 21 has, for example, a suction belt 23 having an opening on the upper surface side in a mesh belt 22 having a continuous mesh portion having a constant width and circulating in one direction.

Therefore, when the backing sheet BP having air permeability is conveyed by the mesh belt 22, a part of the pulp which is defibrated by the defibrating cylinder 7 and guided by the guide duct 24 has a mesh shape on the backing sheet BP. Laminated with the same width. The pattern drum 25 rotates in one direction and is arranged so as to perform a conveying operation in cooperation with the base conveyor 21. As shown in FIG. 6, a continuous mesh portion 26 having a constant width, for example, is provided on the outer peripheral surface. An arc-shaped suction duct 27 having an opening on the peripheral surface side is provided inside.

Therefore, a part of the pulp defibrated by the defibrating cylinder 7 and guided by the guide duct 24 is laid on the mesh portion 26 of the pattern drum 25 with the same width as the shape thereof. Then, when the pulp layer spread on the mesh portion 26 by the rotation of the pattern drum 25 enters between the pattern drum 25 and the base conveyor 21, the pulp layer comes off from the opening of the suction duct 27 and the suction on the base conveyor 21 side. Receiving the suction force from the duct 23, the pulp layer placed on the backing paper BP on the side of the base conveyor 21 rides on the pulp layer, and two piled pulp layers are formed on the backing paper BP.

As a result, as shown in FIG. 7, an absorbent body in which two pulp layers P1 and P2 are piled on the backing paper BP is obtained. Thereafter, both edges of the backing sheet BP are folded by a folding device (not shown) to complete the absorber.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an absorber manufacturing apparatus including an absorbent pulp defibrating apparatus according to an embodiment of the present invention.

Fig. 2 Schematic diagram of defibration machine from pulp roll

FIG. 3 is a perspective view of a defibrating cylinder.

FIG. 4 is a timing chart showing the operation of a piston and the like.

FIG. 5 is a schematic cross-sectional view in another operating state of the pulp defibrating device for an absorbent body.

FIG. 6 is a perspective view of a pattern drum.

FIG. 7 is a perspective view of the absorbent body after stacking.

FIG. 8 is a schematic cross-sectional view of a pulp defibrating device for an absorbent body showing a conventional example.

[Explanation of symbols]

 Reference Signs List 6 Fibrillation device 7 Fibrillation cylinder 8 Popper section 9 Pressure feed passage 10A, 10B Pulp supply passage 11A, 11B Servo motor 12A, 12B Piston 13A, 13B Switching valve 14A, 14B Stopper 15A, 15B Pressure sensor 20 Fibrillation device 21 Base conveyor 25 pattern drum

Claims (10)

[Claims] 1. A pulp supply passage for supplying pulp to a defibrating surface on an outer periphery of a rotating defibrating cylinder, and when pulp is defibrated, enters the pulp supply passage from outside the pulp supply passage. A pulp defibration method for an absorbent body, wherein a pulp is compressed in a direction of a passage by a piston. 2. The pulp defibration method for an absorbent body according to claim 1, wherein the pulp supply passage is branched into a plurality of passages, and the pulp is compressed by a piston alternately in each passage. 3. The pulp defibration method for an absorber according to claim 2, wherein the supply of pulp from the upstream side is switched at a branch portion of the pulp supply passage. 4. A pulp supply passage wherein an outlet side downstream of the piston is opened and closed by a stopper, and the pulp is compressed in cooperation with the piston when closed.
The pulp defibration method for an absorbent body according to any one of claims 1 to 3. 5. The method according to claim 1, wherein the state of compression of the pulp is detected, and the operation of the piston is controlled based on the detected state.
The pulp defibration method for an absorbent body according to any one of claims 1 to 4. 6. A pulp defibrating device for an absorber for supplying pulp to a defibrating surface on the outer periphery of a rotating defibrating cylinder by a pulp supply passage and defibrating the pulp. Rush into the pulp supply passage,
A pulp defibrating device for an absorbent body, comprising a piston for compressing pulp in the direction of the passage. 7. The pulp defibrating device for an absorbent body according to claim 6, wherein the pulp supply passage is branched into a plurality of parts, and a piston is provided in each of the branches. 8. The pulp defibrating device for an absorbent body according to claim 7, wherein a switching valve is provided at a branch portion of the pulp supply passage. 9. The pulp supply passage according to claim 6, further comprising a stopper capable of opening and closing the outlet side downstream of the piston and compressing the pulp in cooperation with the piston when closed. A pulp defibrating device for an absorbent body according to any one of the first to third aspects. 10. The apparatus according to claim 6, further comprising a sensor for detecting a compression state of the pulp, and a control circuit for controlling the operation of the piston based on a signal from the sensor. A pulp defibrating device for an absorbent body according to any one of the first to third aspects.