JPH06248600A - Method for drying pulp mold - Google Patents

Abstract

PURPOSE:To obtain a method for drying pulp mold by uniformly drying a pulp mold formed from a pulp slurry in a relatively short time. CONSTITUTION:A pulp mold 20 on a conveyor belt 14 is dried with far infrared rays from a heater and a relatively weak hot air until the water content reaches about 50%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method of drying a pulp mold formed from pulp slurry.

[0002]

2. Description of the Related Art When transporting a predetermined product or the like, the product or the like is packed with a packing material having a recess corresponding to the shape of the product or the like. Since this packaging material is usually made of a relatively expensive material such as expanded polystyrene and is expensive, it is made of pulp such as cardboard or waste paper for the purpose of cost reduction of packaging material and effective use of resources. The packaging material is molded,
It is called pulp mold. This pulp mold is usually manufactured by sucking pulp slurry and adsorbing it on the molding surface of a molding die to mold it into a predetermined shape, followed by drying with hot air in a drying furnace.

[0003]

However, when the pulp mold formed from the pulp slurry as described above is rapidly dried by hot air, it is difficult to obtain a uniform dry state between the surface and the inside of the pulp mold. As a result, the pulp mold is likely to be deformed such as warped or distorted, which may impair the dimensional accuracy of the pulp mold and thus the packing property.

On the other hand, if the pulp mold is slowly dried to some extent in the sun and then dried in a drying furnace, it is considered that the deformation of the pulp mold can be preferably prevented. Has a drawback that the drying time is significantly lengthened and the productivity is significantly lowered.

The present invention has been made in view of the above circumstances, and an object thereof is to dry a pulp mold capable of uniformly drying a pulp mold formed from pulp slurry in a relatively short time. To provide a method.

[0006]

The gist of the present invention for achieving the above object is a method of drying a pulp mold formed into a predetermined shape from pulp slurry, wherein the water content of the pulp mold is Until it reaches at least 60%, the pulp mold is dried by irradiating it with far infrared radiation.

[0007]

In the method of drying a pulp mold having such a constitution, far infrared rays are irradiated to the pulp mold formed from pulp slurry until the water content of the pulp mold reaches at least 60%. Causes the pulp mold to dry. In this case, since the far infrared rays penetrate into the pulp mold to heat the pulp mold, the pulp mold can be dried in a relatively short time, and the temperature difference between the surface and the inside of the pulp mold is suitably reduced. Since the dried state of the pulp mold can be obtained uniformly, the deformation of the pulp mold during drying can be preferably prevented. Further, when the water content reaches 60%, the pulp mold becomes relatively difficult to be deformed, and even if the subsequent rapid drying is performed with hot air, for example, the deformation hardly occurs. Its water content is at least 6
It only has to be done until it reaches 0%.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a view showing a preferred example of a pulp mold drying apparatus to which the pulp mold drying method of the present invention is applied, and 10 is a main body of the apparatus. Device body 10
As shown in FIGS. 1 and 2, is a horizontal type having a relatively long rectangular tube shape, and a conveyor belt 14 in which a large number of pallets 12 are connected in an endless ring shape.
A part of the circumferential direction of is accommodated. Conveyor belt 1
4 is introduced into the apparatus main body 10 through an opening 16 provided at one longitudinal end of the apparatus main body 10 and is provided at the other longitudinal end of the apparatus main body 10 by being rotationally driven by a driving unit (not shown). From the opening 18 to the device body 10
The conveyor belt 14 is designed to be discharged to the outside.
The pulp mold 20 to be dried is sequentially placed on the pallet 12 that is introduced into the apparatus main body 10, and the dried pulp mold 20 on the pallet 12 that is discharged to the outside of the apparatus main body 10 of the conveyor belt 14 is It is designed to be removed sequentially. The pallet 12 is a member (for example, a perforated steel plate) having a large number of through holes (not shown) penetrating in the thickness direction in order to allow far infrared rays and hot air from a heater 22 described below located below the conveyor belt 14 to pass therethrough. And wire mesh).

The pulp mold 20 has a recess (not shown) corresponding to the shape of a predetermined product or the like, and is used as a packing material for carrying the product or the like. It is molded as follows.

First, a molding die having a molding surface having a shape corresponding to that of the pulp mold 20 and having a large number of pores formed in the molding surface formed therein, and the pulp are disintegrated while being stirred in water to form a slurry. Prepare a device (so-called pulper) for making pulp sludge in the state, and suck the pulp sludge by vacuuming through the large number of pores with the molding die immersed in the pulp sludge in the pulper Adsorb to the molding surface of the mold. The pulp mold 20 is obtained by pulling up the molding die from the pulp slurry while continuing the evacuation and taking out the pulp attached to the molding surface of the molding die. The pulp mold 20 molded in this way has a water content of, for example, about 75% to 80%. In this state, the conveyor belt 14
Supplied up.

Inside the main body 10 of the apparatus, the conveyor belt 14 is longitudinally extended from the vicinity of the end of the main body 10 on the side of the opening 16 while facing the conveyor belt 14 with a predetermined distance therebetween. A plurality of heaters 22 are provided at predetermined intervals over the intermediate portion in the direction. As shown in FIGS. 3 and 4, the heater 22 is provided with a bottomed cylindrical member 24 made of, for example, metal such as iron or stainless steel, or ceramic, and the peripheral wall of the cylindrical member 24. Has a plurality of outlets 26 formed at predetermined intervals along the longitudinal direction, and the positions around the axis are determined so that the outlets 26 face the conveyor belt 14 in the apparatus body 10. There is. A ceramic film 28 (not shown in FIG. 3) is coated on the outer peripheral surface of the peripheral wall of the cylindrical member 24. The ceramic coating 28 is formed by applying ceramic powder such as zirconia, zircon, alumina, titania, manganese oxide, or cobalt oxide to the outer peripheral surface of the cylindrical member 24 by coating or plasma spraying. It has a thickness of, for example, about 10 μm to 100 μm, and is heated to a high temperature gas described later, for example, 1 μm to 20 μm.
It emits far infrared rays having a wavelength of about μm.

As shown in FIG. 1, the opening side end (right end in FIG. 4) of the cylindrical member 24 of the plurality of heaters 22 is connected to the high temperature gas generator 34 via the passage 30 and the circulation fan 32. Each is connected. The high-temperature gas generator 34 includes a burner 36 and a combustion chamber 38, and the fuel supplied to the burner 36 together with the air is burned in the combustion chamber 3
It is designed to be combusted in 8. The high-temperature gas generated in the combustion chamber 38 due to the combustion is the circulation fan 32.
Is supplied to the inside of each heater 22 through the passage 30. As a result, when the heater 22 is heated, far infrared rays are radiated from the ceramic coating 28, irradiate the pulp mold 20 from both sides in the vertical direction of the conveyor belt 14, and at the same time, the high temperature gas blown out from the outlet 26 of the heater 22. Are sprayed onto the pulp mold 20 from both sides in the vertical direction of the conveyor belt 14. The hot gas is blown from the heater 22 by the gas flow (hereinafter referred to as hot air).
The main purpose is to smoothly dry the pulp mold 20 by far infrared rays by blowing away the steam remaining on the surface of the pulp mold. In this case, the strength of the hot air blown onto the pulp mold 20 is such that the steam on the surface of the pulp mold 20 can be suitably blown off by the hot air from the heater 22 and the pulp mold 20 is not deformed. Heater 22
It is determined in advance in relation to the feed pressure of the high temperature gas to the heater 22, the size of the outlet port 26 of the heater 22, the distance between the heater 22 and the conveyor belt 14, and the like.

On the upper wall of the end portion (right end portion in FIG. 2) of the apparatus main body 10 located on the downstream side of the conveyor belt 14,
As shown in FIG. 2, a pair of through holes 40 and 42 are provided. As shown in FIG. 1, an exhaust fan 46 is connected to one of the through holes 40 via a passage 44, and the exhaust fan 46 causes a part of the gas in the apparatus body 10 to go outside together with water vapor. It is supposed to be discharged. The other through hole 42 is connected to the combustion chamber 3 through the passage 48.
8 is communicated with the inside of the combustion chamber 38, whereby a part of the gas of relatively high temperature in the apparatus body 10 is introduced into the combustion chamber 38 and reused according to the negative pressure in the combustion chamber 38 by the circulation fan 32. It has become so. By suctioning the inside of the apparatus body 10 from the through holes 40 and 42 as described above, the relatively high temperature gas in the apparatus body 10 flows from the left side to the right side in FIG.

In the pulp mold drying apparatus constructed as described above, for example, one heater is provided inside each heater 22.
With the high temperature gas of about 50 ° C. to 300 ° C. supplied, the molded pulp mold 20 having a water content of about 75% to 80% is placed on the conveyor belt 14, and the residence time is, for example, 15 minutes to 30 minutes. The pulp mold 20 is dried to a water content of about 10%, for example, by passing the inside of the apparatus main body 10 at a predetermined speed so that the water content becomes about 10%. That is, the pulp mold 20 introduced into the apparatus main body 10 is heated from both sides in the vertical direction by the far infrared rays from the ceramic film 28 of the heater 22 while the hot air from the outlet 26 of the heater 22 is blown from both sides in the vertical direction. As a result, when passing through the heater 22 located on the rightmost side in FIG. 2, the water content is dried to, for example, about 50%, and the heater 2 on the rightmost side is dried.
After passing through 2, the inside of the apparatus body 10 is heated by a relatively high-temperature gas flow flowing to the right in FIG. 2, so that when it is discharged from the apparatus body 10, the water content is about 10% or more. It can be dried. In this case, the surface temperature of the heater 22 is, for example, 150 ° C to 30 ° C.
The temperature of the exhaust fan 4 becomes about 0 ° C. and the ambient temperature in the apparatus body 10 becomes, for example, about 80 ° C. to 150 ° C.
The temperature of the exhaust gas discharged from 6 is 80 ° C. to 1
It will be about 20 ° C.

As described above, according to this embodiment, the pulp mold 20 molded from pulp slurry has a water content of 5%.
It is dried by far infrared rays emitted from the heater 22 until it reaches about 0%. In this case, the far infrared rays permeate the inside of the pulp mold 20 and heat it, so that the pulp mold 20 can be dried quickly and the temperature difference between the surface and the inside of the pulp mold 20 is suitably reduced. As a result, the dried state of the pulp mold 20 can be obtained uniformly, and deformation of the pulp mold 20 such as warpage and distortion during drying can be suitably prevented. Further, since the pulp mold 20 can be uniformly dried with far infrared rays in this manner, there is an advantage that it is possible to manufacture a thicker or larger pulp mold.

Further, according to the present embodiment, the hot air that does not deform the pulp mold 20 is blown from the heater 22, so that the water vapor staying on the surface of the pulp mold 20 is blown away and the far infrared rays generate the pulp. Since the mold 20 is smoothly dried and the pulp mold 20 is also dried to some extent even by the hot air, the drying time of the pulp mold 20 is more preferably shortened.

Further, according to the present embodiment, the pulp mold 20 can be dried at once to a desired moisture content uniformly without drying the pulp mold 20 to some extent in the sun, etc. There is an advantage that the steps from molding to drying of 20 can be suitably lined.

Further, according to the present embodiment, after the pulp mold 20 is dried by the heater 22 to a water content of about 50%, a relatively high temperature gas flow flowing rightward in the apparatus main body 10 in FIG. Since it is configured to be dried to a water content of about 10% by utilizing it, when the water content of about 10% is dried by the heater 22, the heater 2 is used.
2 is advantageous in that the drying device can be provided at a lower cost than the case where the water is dried to a water content of about 50% and then separately prepared, for example, by a drying device using hot air.

Further, according to this embodiment, a part of the relatively high temperature gas in the apparatus body 10 passes through the passage 48 and the combustion chamber 3
Since the pulp mold 20 is configured to be returned to the inside and reused, there is an advantage that the pulp mold 20 can be efficiently dried and the running cost of the drying device can be suitably reduced.

Next, another embodiment of the present invention will be described. In the following description, the same parts as those in the above-described embodiment will be designated by the same reference numerals and the description thereof will be omitted.

In FIG. 5, a horizontal type apparatus in which a plurality of pallets 12 are connected in an endless annular shape and three conveyor belts 50, 52 and 54 are circumferentially partially separated from each other by a predetermined distance in the vertical direction. The pulp mold 20 is configured to be moved horizontally in the main body 10, and the pulp mold 20 is placed on each of the conveyor belts 50, 52, 54, and the upper wall of the apparatus main body 10 and the conveyor belt 50 are Between the conveyor belt 50 and the conveyor belt 52, between the conveyor belt 52 and the conveyor belt 54, and between the conveyor belt 54 and the apparatus body 10.
A plurality of heaters 22 are provided between the lower wall and the lower wall at predetermined intervals in the longitudinal direction of the apparatus body 10. In addition, the heater 22 between the conveyor belt 50 and the conveyor belt 52 and the heater 22 between the conveyor belt 52 and the conveyor belt 54 are located at the air outlet 26 (at the position opposite to each other in the radial direction of the cylindrical member 24). (Not shown), and blows hot air to both sides in the vertical direction.

Further, in FIG. 6, the plurality of pallets 12 are respectively attached to, for example, endless annular chains (not shown) and are configured to be vertically movable in the vertical apparatus main body 56. The pulp mold 20 is provided below the apparatus main body 56.
Are supplied to and discharged from the pallet 12, and a plurality of heaters 22 are arranged on both sides of the pallet 12 at predetermined vertical intervals.
Are provided respectively. In this case, in order to blow hot air onto the pulp mold 20 on the pallet 12 from both sides in the vertical direction, for example, the heater 22 on one side (left side in FIG. 6) of the pallet 12 blows hot air diagonally upward. The position around the axis is determined, and the position around the axis of the heater 22 on the other side (right side in FIG. 6) of the pallet 12 is determined so as to blow hot air obliquely downward.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other modes.

For example, in the above embodiment, the pulp mold 20 has the heater 22 until the water content becomes about 50%.
Is dried by far infrared rays and the like, and is then dried up to about 10% by utilizing a gas flow laterally flowing in the apparatus main body 10, but this is not always necessary. May be dried with far infrared rays from the heater 22 or the like until it reaches about 10%, or the pulp mold 20 becomes relatively hard to deform when the water content reaches 60%, so that the water content is at least It is also possible to dry it with far infrared rays from the heater 22 until it reaches about 60%, and thereafter to dry it by blowing hot air relatively strongly.
In short, the water content of the pulp mold 20 is at least 6
If you dry it with far infrared rays until it reaches 0%,
Therefore, the effect of the present invention that the pulp mold 20 can be uniformly dried in a relatively short time can be obtained.

Further, in the above-mentioned embodiment, the heater 22 is constructed to have the air outlet 26, and the hot air from the air outlet 26 is used to blow off the steam remaining on the surface of the pulp mold 20. There is a device body 1
In the case where the water vapor on the surface of the pulp mold 20 can be suitably blown off by a gas flow or the like flowing in the lateral direction of 0,
It is not always necessary to provide the air outlet 26.

Further, in the above-described embodiment, the heater 22 is heated by the relatively high temperature combustion gas supplied therein, but it may be heated by another heat source such as electricity.

Further, in the above-mentioned embodiment, the heater 22 is constituted by the cylindrical member 24 and the ceramic film 28 which is formed on the outer peripheral surface of the cylindrical member 24 over the entire circumference and radiates far infrared rays. However, it is not always necessary,
For example, a ceramic film may be formed only on a part of the outer peripheral surface of the cylindrical member 24 in the circumferential direction on the side of the air outlet 26, or the cylindrical member 24 itself may be made of a ceramic that emits far infrared rays. Good.

In the above embodiment, the pulp mold 20 may be mixed with resin, aluminum foil or the like for the purpose of increasing the amount or reinforcing the pulp mold 20.

In addition, the present invention can be variously modified without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a pulp mold drying apparatus to which a method of drying a pulp mold of the present invention is preferably applied, and is a diagram showing a configuration.

FIG. 2 is a view showing a main part of a cross section taken along line II-II in FIG.

FIG. 3 is an enlarged perspective view of the heater shown in FIG.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a diagram for explaining another example of the present invention,
It is a figure corresponding to FIG.

FIG. 6 is a diagram for explaining still another example of the present invention, and is a diagram corresponding to FIG. 2;

[Explanation of sign]

 20: Pulp mold

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsunori Kawachi 3-36 No. 1 Noritake Shinmachi, Nishi-ku, Nagoya-shi, Aichi Noritake Company Limited

Claims (1)

[Claims] 1. A method of drying a pulp mold formed into a predetermined shape from pulp slurry, wherein the pulp mold is irradiated with far infrared rays until the water content of the pulp mold reaches at least 60%. A method for drying a pulp mold, characterized in that the pulp mold is dried by.