JPH05287114A - Method for drying and feeding particle for preexpanding machine and its apparatus - Google Patents

Abstract

PURPOSE:To obtain a method for drying and feeding grains for a preexpanding machine in which the drying time is shortened and the productivity is improved by transferring preexpanded particles to a drying hopper, then blowing up the particles together with hot air for drying from a blowoff nozzle into a drying column and drying the particles and its apparatus. CONSTITUTION:Preexpanded particles discharged from a preexpanding machine 1 into a discharging hopper 3 are fed into a part formed by providing a partition wall therein or a separately installed drying hopper 12 and blown up into a drying column 14, erected in the drying hopper 12 and capable of passing water and air therethrough without passing the preexpanded particles and then dropped. The resultant preexpanded particles are sucked by blasting hot air to an ejector 15 provided at a delivery outlet of the bottom of the drying hopper 12. Thereby, the particles are fed, circulated in the drying column 14 and blown up therein to dry and remove moisture of the preexpanded particles, which are simultaneously heated and fed through a particle feeding pipe 24 to a silo, etc., with the hot air. The drying time can be shortened and the preexpanded particles can readily be heated by this method and apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry granulation method and apparatus for a pre-expanding machine, and more specifically, it mainly prepares a pre-expanding machine for pre-expanding expandable resin particles at a relatively high expansion ratio of about 15 times or more. Foaming (Hereinafter, abbreviated as "high-times foaming")
The present invention relates to a dry granulation method and apparatus suitable for the pre-expanded particles obtained.

[0002]

2. Description of the Related Art Conventionally, the following three types of methods have been employed to dry pre-expanded particles obtained by heating and expanding foamable resin particles with steam in a pre-expanding machine. The first method is to blow cold air, warm air, or hot air into the pre-foaming machine to dry it after the completion of pre-foaming. In the second method, after drying by the first method, the pre-expanded particles are pressure-fed with warm air or hot air to an aged silo to further dry the particles (Japanese Patent Laid-Open No. 1-249408). In the third method, after the completion of pre-foaming, the pre-foaming machine is discharged without drying in the pre-foaming machine, the discharged pre-foamed particles are stored in a storage tank or a tunnel-shaped container, and dried by blowing hot air. is there.

[0003]

However, according to the first method of the above-mentioned conventional methods, the time required for one cycle of the prefoaming machine (feeding of raw material → preliminary foaming → drying → discharging) becomes long. , The processing capacity of the pre-foaming machine decreases. Further, according to the second method, when the pre-expanded particles have a low expansion ratio, the specific gravity of the pre-expanded particles is large, and therefore the particles cannot be fed by pressure feeding. Further, the temperature does not rise sufficiently during grain feeding due to the latent heat of vaporization of the surface moisture of the pre-expanded particles. For example, according to the experiments conducted by the present inventors, when hot air of 80 ° C. is used, the temperature of the pre-expanded particles is only about 5 ° C. higher than room temperature. Further, according to the third method, since hot air is blown into the pre-expanded particles in the stored state, it takes a long time to dry, and further, when the pre-expanded particles have a low expansion ratio and a large specific gravity, it takes a longer time. Moreover, the installation place of the drying equipment becomes wider.

An object of the present invention is to improve the conventional grain feeding hopper to eliminate the above problems.

[0005]

In order to achieve the above object, the dry granulation method for a pre-expanding machine of the present invention divides the pre-expanded particles discharged from the pre-expanding machine into the discharge hopper into the discharge hopper section. Particles were formed in a drying hopper section that was formed by providing a wall or was separately provided, and was erected in the discharge hopper section.
The pre-expanded particles that have been blown up and dropped through the drying tower that allows moisture and air to pass but does not pass the pre-expanded particles,
Hot air is blown into the ejector provided at the bottom outlet of the dry hopper to suck the hot air, and the particles are circulated through the drying tower and blown up into the drying tower to dry and remove the water content of the pre-expanded particles. A dry granulation method for a pre-expanding machine characterized by heating together with the content, and a dry granulation apparatus used in the method of the present invention is a discharge hopper section provided at a pre-expanded particle discharge port of the pre-expanding machine. A partition wall is provided to form a dry hopper part, or a separate dry hopper part is provided, and a pre-expanded particle pressure-feeding ejector is provided at the outlet of the bottom of the discharge hopper and the working fluid intake port of the ejector is provided. Connect a grain blower, and install a cylindrical drying tower on the open upper surface of the drying hopper section that allows moisture and air to pass but does not allow pre-expanded particles to pass, and at the outlet of the bottom. Provided with a foamed particle pressure-feeding ejector, a blowing nozzle is attached to the side wall of the drying hopper portion toward the drying tower, and a discharge side of the ejector provided in the discharge hopper is connected to a blowing nozzle provided in the drying hopper. The discharge side of the ejector provided in the drying hopper is connected to the blowout nozzle or a blowout nozzle separately provided via a switching damper, and a hot air generator is connected to a working fluid inlet of the ejector. The contents are dry granulation devices for pre-foaming machines.

[0006]

Embodiments of the present invention will now be described with reference to the drawings. The granulating hopper for the pre-foaming machine of the present invention is shown in FIG.
As shown in, the pre-foamed particles are transferred from the discharge hopper section 3 provided at the lower part of the pre-foamed particle discharge port 2 of the pre-foaming machine 1 and the discharge hopper section 3 to remove moisture on the surface of the particles, And a drying hopper section 12 for raising the temperature of the particles.

The discharge hopper 3 has a rectifying sieve 4 inside.
And an ejector 5 for pressure-feeding the pre-expanded particles is provided at the bottom outlet, and the ejector 5 is a working fluid inlet 6
And a pre-expanded particle discharge port 7, a granulation blower 9 is connected to the working fluid intake port 6 via a blower pipe 8, and a pre-expanded particle discharge port 7 is connected via a transfer pipe 11 to a blow-out nozzle 20 to be described later. The inner pipe 18 is connected.

On the other hand, in the drying hopper section 12, a rectifying sieve 13 is stretched inside, a cylindrical drying tower 14 is erected on a lid mounted on the open upper surface, and pre-expanded particles are provided at the outlet of the bottom section. The ejector 15 for pressure feeding is provided, and the blowing nozzle 20 is attached to the side wall toward the drying tower 14.

The drying tower 14 is composed of a wire mesh, a perforated plate, etc., which allows moisture and air to pass but pre-expanded particles do not pass. The ejector 15 includes a working fluid inlet 16 and a pre-expanded particle outlet 17, and the blow-out nozzle 20 has an inner-outer double-tube structure including an inner tube 18 and an outer tube 19.

Then, a switching damper 22 is provided on the granulating tube 21 connected to the pre-expanded particle discharge port 17 of the ejector 15, and the switching damper 22 is connected to the outer tube 19 of the blowing nozzle 20 via a circulation tube 23. On the other hand, working fluid intake 1
A hot air generator 26 is connected to 6 via a drying pipe 25.

The switching damper 22 is in a "circulation" position where the granulation tube 21 is cut off from the granulation tube 24 and is connected to the circulation tube 23, and the switching damper 22 is cut off from the circulation tube 23 to be connected to the granulation tube 24. It is a three-way damper with a "graining" position. Further, the hot air generator 26 is configured by connecting an air blower 28 to the heater 27 and supplies hot air for drying whose temperature is from room temperature to about 80 ° C.

In the granulating hopper having the above construction, the pre-expanded particles discharged from the pre-expanded particle discharge port 2 of the pre-expanding machine 1 are sized by the rectifying sieve 4 in the discharge hopper section 3 and then once discharged. Stored in the bottom of part 3. Subsequently, the particle-sending blower 9 and the hot air generator 26 enter the operating state, and the switching damper 22 is set to the “circulation” position.

The particle-sending blower 9 sends air to the working fluid intake 6 of the ejector 5 through the blower pipe 8, whereby the ejector 5 uses the air as the working fluid to eject the discharge hopper 3 by its ejector action. The pre-expanded particles are sucked from the above, and are blown through the transfer pipe 11 to the inner pipe 18 of the blowout nozzle 20 attached to the drying hopper 12, and the particles are blown up toward the drying tower 14. At this time, the air is discharged into the atmosphere from the wall surface (the wire mesh) of the drying tower 14, and the pre-expanded particles blown up from the blowing nozzle 20 fall and remain at the bottom of the drying hopper section 12. The hot air generator 26 is
Hot air for drying is sent to the working fluid intake port 16 of the ejector 15 via the drying pipe 25. As a result, the ejector 15 uses the hot air as the working fluid to suck the pre-expanded particles from the outlet of the drying hopper section 12 by its ejector action, mixes with the hot air and discharges the pre-expanded particles from the pre-expanded particle discharge port 17 to the granulation pipe 21, the switching damper. The particles are fed to the outer tube 19 of the blow-out nozzle 20 via the circulation tube 22 and the circulation tube 23, and blown up toward the drying tower 14. The mixture of the pre-expanded particles and hot air blown up from the blowing nozzle 20 enters the drying tower 14, and the hot air dries the pre-expanded particles. As a result, the evaporated water is discharged into the atmosphere from the wall surface of the drying tower 14 together with the hot air, and the pre-expanded particles fall and return to the bottom of the drying hopper section 12.

When the drying cycle is repeated a required number of times to complete the drying, the switching damper 22 is switched to the "granulating" position, and the ejector 15 sucks the dried pre-expanded particles from the outlet of the drying hopper section 12 to generate hot air. Together with the pre-expanded particle discharge port 17, the granulating tube 21, the switching damper 2
Particles are fed to the next facility, for example, an aged silo, via the 2 and the grain feeding pipe 24. Since the pre-expanded particles are granulated with hot air after the surface moisture is dried and removed during circulation drying in the drying hopper, curing in the aged silo is promoted.

For example, the relationship between the expansion ratio of polystyrene pre-expanded particles, the temperature of the particles, and the moldable time (aging time) has an effect on the moldable time of the temperature of the pre-expanded particles as the particle size increases. When the temperature of the pre-expanded particles is 8 ° C, the moldable time is 4 hours. For example, when the particle size (original particles before pre-expansion) is about 12 mm and the expansion ratio is 60 times. On the other hand, in the case of 60 ° C, the time is greatly shortened to 2.4 hours, and the productivity is dramatically improved. According to the dry granulation method of the present invention, the temperature of the pre-expanded particles can be easily heated to 40 ° C or higher, and further 60 ° C or higher.

In the above description, the case where the drying hopper section 12 is newly provided has been described, but a conventional discharging hopper may be partitioned by a partition wall to form a drying hopper section adjacent to the discharging hopper section. The configuration of can also be implemented without any change from the above. Further, although the blowing nozzle 20 has a double pipe structure, two blowing nozzles are attached to the drying hopper section, and one nozzle is used for blowing up the pre-expanded particles fed from the discharge hopper section 3,
Further, another nozzle may be used to blow up the pre-expanded particles that have been circulated with the hot air from the outlet at the bottom of the drying hopper section 3. Further, one blowing nozzle may be provided, and this may serve both to blow up the pre-expanded particles from the discharge hopper section 3 and to blow up the pre-expanded particles that have been circulated and fed. In addition, a heating device 10 is used for the particle feeding blower 9.
May be provided, and instead of the particle feeding blower 9, for example, the hot air generator 26 described above may be used. With this configuration, the pre-expanded particles can be heated even while being transferred from the discharge hopper section 3 to the drying hopper section 12, and the heating efficiency can be further enhanced.

[0017]

As described above, according to the present invention, the pre-expanded particles are transferred from the discharge hopper to the drying hopper, and in the drying hopper, the pre-expanded particles are blown up from the blowing nozzle into the drying tower together with the hot air for drying, so that the drying is extremely performed. It can be dried in a short time, and it is easy to heat the pre-expanded particles to 40 ° C. or higher. Further, since the drying in the pre-foaming machine is unnecessary, the time required for one cycle of the pre-foaming machine is shortened and the processing capacity of the pre-foaming machine is improved. Furthermore, since the pre-expanded particles are dried by hot air and fed by hot air, the pre-expanded particles have an advantage that the pre-expanded particles are heated and the curing in the aged silo is greatly promoted.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a dry granulation apparatus showing an embodiment of the present invention.

[Explanation of symbols]

1 Pre-foaming machine 2 Pre-foamed particle discharge port 3 Discharge hopper section 4 Rectifying sieve 5 Ejector 6 Working fluid intake port 7 Pre-foamed particle discharge port 8 Blower tube 9 Granulating blower 10 Heating device 11 Transfer tube 12 Dry hopper section 13 Rectification Sieve 14 Drying tower 15 Ejector 16 Working fluid inlet 17 Pre-expanded particle discharge port 18 Inner tube 19 Outer tube 20 Blow-out nozzle 21 Grain transfer tube 22 Switching damper 23 Circulation tube 24 Granulation tube 25 Drying tube 26 Hot air generator

Claims (4)

[Claims] 1. Pre-foamed particles discharged from a pre-foaming machine to a discharge hopper are formed by providing a partition wall in the discharge hopper part or fed to a separately provided dry hopper part, and stand in the discharge hopper part. Blow up into the drying tower, which allows water and air to pass but pre-expanded particles do not pass,
The pre-expanded particles that have been dropped are pre-expanded by blowing hot air into an ejector provided at the bottom of the drying hopper so that the pre-expanded particles are sucked and fed to the drying tower for circulation. A dry granulation method for a pre-foaming machine, which comprises removing moisture of particles by drying and heating. 2. A discharge hopper provided in a pre-expanded particle discharge port of a pre-expanding machine is provided with a partition wall to form a dry hopper, or a separate dry hopper is provided, and a discharge port at the bottom of the discharge hopper is provided. A pre-expanded particle pressure-feeding ejector is attached to the ejector, and a granulating blower is connected to the working fluid intake port of the ejector to allow water and air to pass through the open upper surface of the drying hopper, but not the pre-expanded particle. A drying tower is installed upright, and an ejector for pre-expanded particle pressure feed is provided at the bottom outlet, and a blowout nozzle is attached to the side wall of the drying hopper portion toward the drying tower, and the discharge side of the ejector provided in the discharge hopper. Is connected to a blowout nozzle provided in the dry hopper, and the blower is provided to a discharge side of an ejector provided in the dry hopper via a switching damper. A dry granulation apparatus for a pre-foaming machine, which is connected to a discharge nozzle or a separately provided blow-out nozzle, and a hot air generator is connected to a working fluid inlet of the ejector. 3. The dry granulating apparatus according to claim 1, wherein the blowing nozzle has an inner and outer double pipe structure. 4. The dry particle feeder according to claim 2, wherein the particle blower comprises a hot air generator.