JPH0839529A - Method for cleaning of felt for making paper - Google Patents

Abstract

PURPOSE:To enable quality of a product to be maintained by making concentration of hydrochloric acid contained in a material unraised by a method wherein water used for rinsing felt for making paper is neutralized, and the neutralized water is used for mixing a raw material. CONSTITUTION:Felt 1 for making paper from which a thin sheet like material 9 is removed is washed with a rinsing nozzle 6 to remove clogging owing to the material 9. Thereafter, it enters a hydrochloric acid tank, and washed with acid by dipping. Further, it enters a water rinsing tank 8, and the hydrochloric acid stuck to the felt by acid pickling is washed off by squeezing out. The water in the water rinsing tank 8 appropriately enters a neutralizing tank 10, and its acid is neutralized with an alkali solution added from a tower 4 for adding a neutralizer. Thereafter, the water enters a settling chamber 11. Impurities are removed by settling in the settling chamber 11, and charged again into a material feeding box 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a felt for papermaking used in a papermaking machine for producing an inorganic fiber board as an exterior material, a ceiling material or the like.

[0002]

2. Description of the Related Art Conventionally, the following methods have been used for cleaning felts of this type.

Hydrochloric acid is diluted to a concentration of about 5% and used for washing the papermaking felt. After washing, the hydrochloric acid attached to the papermaking felt is washed with water, and the water containing hydrochloric acid is reused for mixing the materials. Since this process is repeated, there is a drawback that the concentration of hydrochloric acid contained in the material becomes high.

There is another method of washing with acetic acid instead of hydrochloric acid, but acetic acid has a drawback that its detergency is weak.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above points, and the felt for papermaking is washed with hydrochloric acid, and the hydrochloric acid used for washing does not mix into the material. The cleaning method is provided.

[0006]

According to a first aspect of the present invention, there is provided a method for cleaning a felt for papermaking used in a papermaking machine for producing an inorganic fiber board, as described in claim 1.
It is characterized by comprising a step of pickling the papermaking felt, a step of washing the papermaking felt with water, a step of neutralizing the water used in the water washing step, and a step of using the neutralized water for mixing the raw materials. This is a method for cleaning a felt for papermaking.

A second invention according to this application is, as described in claim 2, a method for cleaning a papermaking felt used in a papermaking machine for producing an inorganic fiber board, which comprises a step of pickling the papermaking felt. , The step of washing the papermaking felt with water, the step of neutralizing the water used in the step of washing with water, the step of using the neutralized water for mixing the raw materials, the hydrochloric acid used for pickling and the necessary amount of A method for washing a papermaking felt, comprising the step of adding hydrochloric acid and sending the papermaking felt to the step of pickling.

According to a third aspect of the present invention, as described in claim 3, the papermaking felt is washed with hydrochloric acid in a hydrochloric acid tank which is vibrated by an ultrasonic oscillator. It is a method for cleaning a felt for papermaking as described.

A fourth invention according to this application is characterized in that, as described in claim 4, the papermaking felt is washed with hydrochloric acid in a hydrochloric acid tank vibrated by an ultrasonic oscillator. It is a method for cleaning a felt for papermaking as described.

[0010]

[Operation] According to the constitution of claim 1, the water for washing the papermaking felt is reused for mixing the raw materials in a neutralized state.

According to the structure of claim 2, in addition to the above-described function of the structure of claim 1, the hydrochloric acid used for pickling can be purified and reused.

According to the configuration of claim 3, in addition to the above-described action of the configuration of claim 1, the vibration of the ultrasonic oscillator further promotes the cleaning of the papermaking felt.

According to the structure of claim 4, in addition to the above-described action of the structure of claim 2, the vibration of the ultrasonic oscillator further promotes the cleaning of the papermaking felt.

[0014]

EXAMPLES The present invention will be described below based on examples.

The first example shows a method of washing a papermaking felt used in a papermaking machine for producing an inorganic fiber board, which comprises a step of pickling the papermaking felt, a step of washing the papermaking felt with water, The step of neutralizing the water used in the step of washing with water, the step of using the neutralized water to mix the raw materials,
The hydrochloric acid used for pickling is filtered and the necessary amount of hydrochloric acid is added, and the process is sent to the step of pickling the papermaking felt.The papermaking felt is shaken with an ultrasonic oscillator in a hydrochloric acid tank. It is washed with hydrochloric acid.

This will be described in detail with reference to FIG. FIG. 1 shows a so-called long steel papermaking machine. One of the cores of this papermaking machine is an endless belt device 2 using a nylon papermaking felt 1, and 3 is a material supply box to the upper surface of the endless belt device 2 for supplying raw materials. is there.
The papermaking felt 1 of the endless belt device 2 is continuously rotatably moved in the following steps by a roller 16 which is appropriately arranged.

Reference numeral 5 is a suction box arranged on the lower surface of the endless belt device 2. Further, 6 is a water washing nozzle.

Reference numeral 7 is a hydrochloric acid tank, and 8 is a water washing tank.
13 is a settling tank, and 14 is a filter.

In the material supply box 3, there is a material 9 in which Portland cement, fly ash, granulated blast furnace slag, pulp, etc. are mixed with water. The material 9 is placed on the upper surface of the endless belt device 2 according to the movement of the endless belt device 2. To supply.

The mixing ratio of the material 9 is 100 parts of Portland cement and 100 parts of fly ash in this embodiment.
Parts, 100 parts of granulated blast furnace flag, and 15 parts of pulp.

The material 9 placed in a thin layer on the papermaking felt 1 of the endless belt device 2 is sucked by the suction box 5 and dehydrated to be thin (about 15 mm in thickness).
It is formed into a sheet and sent to the next step.

On the other hand, the papermaking felt 1 from which the thin sheet-shaped material 9 has been removed is washed by the water washing nozzle 6 in order to remove the clogging by the material 9, and then enters the 5% hydrochloric acid tank 7. It is pickled by dipping, and then enters the water washing tank 8 to squeeze out the hydrochloric acid attached by pickling. After that, the papermaking felt 1 exiting the washing tank 8 is dehydrated by a drawing process or the like.

In this embodiment, since the ultrasonic oscillator 19 is set in the hydrochloric acid tank 7, the oscillating action of the ultrasonic oscillator 19 allows the felt 1 for papermaking to be washed with hydrochloric acid extremely efficiently.

Also in the conventional method, the papermaking felt 1 from which the material 9 has been removed is washed by jetting a 5% hydrochloric acid solution with a nozzle, and in this case, 200 c for 1 kg of the adhered solid matter.
I needed c. Then, as described above, the washed hydrochloric acid is further contained in the water obtained by washing the papermaking felt 1, and this water is mixed with the material again, so that after continuous operation,
As detected by gas chromatography, the sheet-shaped material contained 400 to 800 ppm of chlorine. This is the result of performing the conventional method.

As shown in this embodiment, the hydrochloric acid tank 7
It is desirable that the concentration of hydrochloric acid used in step 6 be not more than 6 to 7% in order to prevent dissolution damage when a nylon felt is used as the papermaking felt 1.

The water in the washing tank 8 is an alkaline solution which is appropriately added to the neutralization tank 10 from the neutralizer addition tower 4,
After neutralizing the acidity, it enters the precipitation tank 11, the impurities are precipitated and removed in the precipitation tank 11, and the material is supplied again to the material supply box 3. The movement of the water in the water washing tank 8 to the neutralization tank 10 and the precipitation tank 11 is performed by quantitative circulation using an overflow system, a pump 15, and the like.

The water recharged to the material supply box 3 is
Since it is neutralized, even by repeated use,
It does not increase the concentration of hydrochloric acid contained in material 9. When the amount of chlorine in the sheet-shaped material 9 was measured after continuous operation, the sheet-shaped material 9 contained 20 to 40 ppm of chlorine. This is a much smaller value than 400 to 800 ppm when the conventional technique is used as described above.

The hydrochloric acid in the hydrochloric acid tank 7 is pumped by the pump 15.
It is transferred to a settling tank 13 as appropriate, and while the reduced hydrochloric acid is replenished from a replenishing tower 18, impurities are precipitated and removed, filtered by a filter 14, and then returned to the settling tank 13 for reuse.

The papermaking machine repeats the above steps. Then, the thin sheet-shaped material 9 removed from the papermaking felt 1 is press-molded (about 50 kg / cm ² ),
A plate material is obtained by curing by steam curing, and then cut and cut into a predetermined size to form an exterior building board or the like. Since the chlorine content is suppressed to 100 ppm or less as described above, the waste generated by cutting, cutting, etc. at this time, again,
It can be used as a manufacturing material such as cement. Therefore, there is no waste of material.

Next, a different embodiment of the present invention will be described with reference to FIG. One of the cores of this paper making machine is an endless belt device 2 using a nylon papermaking felt 1, and 3 is a material supply box to the upper surface of the endless belt device 2. The felt 1 for papermaking of this endless belt device 2
Is continuously rotated by the appropriately arranged roller 16 in the following steps.

Reference numeral 4 is a suction box 5 arranged on the lower surface of the endless belt device 2. Further, 6 is a water washing nozzle, 12 is a water washing nozzle, and 17 is a pickling nozzle.

The papermaking felt 1 from which the thin sheet-shaped material 9 has been removed is washed by the water washing nozzle 6 in order to remove the clogging by the material 9 and then washed by the pickling nozzle 17.
It is washed with hydrochloric acid having a concentration of%, and further the attached hydrochloric acid is washed off with the water washing nozzle 12.

A hydrochloric acid tank 7 is arranged under the pickling nozzle 17 and stores the hydrochloric acid after cleaning which flows down under the pickling nozzle 17.

Reference numeral 8 denotes a water washing tank, which is arranged below the water washing nozzle 12 and stores the acidic water after washing which flows down under the water washing nozzle 12. Reference numeral 14 is a neutralizer addition tower for adding an alkaline solution to the water washing tank 8 to neutralize the stored acidic water.
The neutralized water is recharged to the material supply box 3.
Since this water is neutralized, the concentration of hydrochloric acid contained in the material 9 does not increase even if it is repeatedly used, as in the above-mentioned embodiment. Therefore, the surplus portion cut off from the thin sheet-shaped material 9 removed from the papermaking felt 1 can be reused as in the above embodiment.

[0035]

According to the first aspect of the present invention, the water for washing the papermaking felt is reused for mixing the raw materials in a neutralized state. Since this water is neutralized, even if it is used repeatedly, it does not increase the concentration of hydrochloric acid contained in the material and does not impair the product quality.

According to the second aspect of the present invention, in addition to the above-described action according to the first aspect of the present invention, the hydrochloric acid used for pickling can be purified and reused. Therefore, the manufacturing efficiency is good.

According to the invention of claim 3, in addition to the above-mentioned action according to the invention of claim 1, the vibration of the ultrasonic oscillator further promotes the cleaning of the felt for papermaking. Therefore, it is effective for manufacturing a good product.

According to the invention of claim 4, in addition to the above-mentioned action according to the invention of claim 2, the vibration of the ultrasonic oscillator further promotes the cleaning of the papermaking felt. Therefore, it is effective for manufacturing a good product.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a side view showing another embodiment of the present invention.

[Explanation of symbols]

 1 Felt for papermaking 2 Endless belt device 3 Material supply box 4 Addition tower 5 Suction box 6 Water washing nozzle 7 Hydrochloric acid tank 8 Water washing tank 9 Material 10 Neutralizing tank 11 Precipitation tank 12 Water washing nozzle 13 Precipitation tank 14 Filter 15 Pump 16 Roller 17 Pickling nozzle 18 Replenishing tower 19 Ultrasonic oscillator

Claims (4)

[Claims] 1. A method for cleaning a papermaking felt used in a papermaking machine for producing an inorganic fiber board, which comprises a step of pickling the papermaking felt, a step of washing the papermaking felt with water, and a step of washing with the water. A method for cleaning a felt for papermaking, comprising a step of neutralizing water and a step of using the neutralized water for mixing raw materials. 2. A method for cleaning a papermaking felt used in a papermaking machine for producing an inorganic fiber board, which comprises a step of pickling the papermaking felt, a step of washing the papermaking felt with water, and a step of washing with the water. The step of neutralizing water, the step of using the neutralized water to mix the raw materials, the hydrochloric acid used for pickling is filtered, and the necessary amount of hydrochloric acid is added to the step of pickling the papermaking felt. A method for cleaning a felt for papermaking, comprising the steps of: 3. The method for cleaning a papermaking felt according to claim 1, wherein the papermaking felt is washed with hydrochloric acid in a hydrochloric acid tank which is vibrated by an ultrasonic oscillator. 4. The method for cleaning a papermaking felt according to claim 2, wherein the papermaking felt is washed with hydrochloric acid in a hydrochloric acid tank which is vibrated by an ultrasonic oscillator.