JP2000071285A - Contaminantless hopper of molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly heat and fry a molding material and prevent the production of a defective owing to a contaminant by providing a heating pipe in the spiral state and projecting a plurality of stirring plates at a predetermined distance lengthwise and crosswise on the inner wall of a body, so as to heat and dry the molding material from inside an outside of the body. SOLUTION: A hopper 1 comprises a cylindrical body 10, a material discharging cylinder 12 coupled to the lower porting 11 formed have a funnel shape, and a cover member 14 having an exhausting pipe 13, and the lower end opening of the material discharging cylinder 12 is connected to the material introducing port of a heating cylinder, thereafter being provided in a molding machine. Heating pipes 21, 22, 23 for a heat medium flowing from a temperature controller 2 are provided at regular intervals in a spiral in the inner portion of the body 10 over the lower portion 11 and the vicinity of the upper edge, on the outer periphery thereof, and in the inner portion of the material discharging cylinder 12. A plurality of stirring plates 3, 3 are projected lengthwise and crosswise at a predetermined distance on the inner wall of the body. The heating pipes 21, 22, 23 are formed of a pipe material excellent in the heat conductivity and corrosion resistance, and the surface is coated with ceramic.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hopper provided with a heating means used by connecting a lower end opening to a material inlet of a heating cylinder such as an injection molding machine or an extrusion molding machine.

[0002]

A molding material such as plastic molded by an injection molding machine or the like is plasticized from a moisture-absorbing molding material to form a molded product. Most of the molding materials are used after the moisture absorbed by a dryer is dried, because the molding material becomes defective. This drying process adopts a hot air drying method in which heated and dried air is blown upward from the lower part of the hopper, and the drying air, which is the heating medium for the molding material, is obtained by directly heating the air in the factory with a heater or the like. Has been generated.

[0003] Since the air in the factory contains dust and carbides are generated on the surface of the heater, the dry air is supplied to the hopper through a filter. It is impossible to completely remove even fine contaminants in dry air, and it is extremely difficult to eliminate defective products due to contamination.

In particular, in the molding of optical moldings and transparent moldings, in which even fine defects are regarded as defectives, high-performance filters are used and frequent maintenance is performed to minimize the occurrence of defectives due to contamination. However, as the filter becomes denser, the flow rate of dry air decreases and the heating efficiency decreases, and by setting an appropriate maintenance time, productivity can be improved, and dust in the air can be generated. It is said that the amount varies not only depending on the environment in the factory but also on the working conditions, and therefore involves technical difficulties.

[0005] Furthermore, the molding material is granular, and there is a difference in the size of the voids generated between the particles depending on the orientation of the particles. Even from the viewpoint of the fluid characteristics, the dry air flows through the voids having low resistance, so that the drying unevenness occurs. Easy to occur. Although this drying unevenness is eliminated by uniformly flowing dry air between particles,
That requires a lot of air and pressure.

The above problems in such dry air are as follows.
The problem can be solved by heating the molding material by electromagnetic waves or infrared rays, or by heating with a heat pipe.However, it is difficult to adopt electromagnetic waves or infrared rays in terms of cost. Due to limitations, it is unsuitable for generally heating the molding material in the hopper.

The present invention has been conceived in view of the above circumstances, and an object of the present invention is to employ a heating pipe to directly heat and dry a molding material in a hopper by direct heating by a heating medium, and to control defective products due to contamination. An object of the present invention is to provide a hopper of a molding machine provided with a drying means having a new configuration capable of preventing the occurrence of wrinkles.

[0008]

According to the present invention, there is provided a hopper provided in a molding machine by connecting a lower end opening to a material input port of a heating cylinder, wherein the hopper has a funnel-shaped lower portion. It consists of a cylindrical main body with a series of delivery cylinders and a lid member having an exhaust pipe, and the inside and outside of the main body extending from the funnel-shaped lower part to the vicinity of the upper edge thereof, by the flow of the heat medium from the temperature controller. A configuration in which a heating pipe is spirally arranged, a plurality of stirring plates are protruded vertically and horizontally on the inner wall of the main body at required intervals, and the molding material is heated and dried from inside and outside the main body. is there.

In the present invention, a heating pipe for circulating a heat medium is spirally disposed inside or on the outer peripheral surface of the material delivery cylinder, and a supply pipe for dry air from a temperature controller is provided on a side portion. In addition, a required number of heat radiating plates are provided at regular intervals on the heating pipe in the main body.

In the hopper having such a configuration, the peripheral wall of the main body is heated by the outer heating pipe, and the molding material in the hopper is also heated from the periphery by the peripheral wall of the main body. In addition, uniform heating is performed, and the drying efficiency is significantly improved as compared with the case where only internal heating is performed.

Further, since the heating and drying of the molding material is performed indirectly through a heating pipe, there is no molding failure due to contamination, which is a problem of direct drying with dry air, and optical molded products and transparent products are not dried. It can be used for molding to improve quality and productivity.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawing, reference numeral 1 denotes a hopper, which comprises a cylindrical main body 10, a material delivery cylinder 12 connected to a lower part 11 formed in a funnel shape, and a lid member 14 having an exhaust pipe 13. Although not shown in the drawing, the lower end opening of the material delivery cylinder 12 is connected to the material charging port of the heating cylinder and provided in the molding machine.

A heat medium (a liquid such as oil or water or a gas such as air) from the temperature controller 2 is provided inside and outside of the main body 10 from the lower portion 11 to the vicinity of the upper edge thereof and inside the material delivery cylinder 12. ) Heating pipes 21, 22, 23
Are arranged spirally at equal intervals, and a plurality of agitating plates 3, 3 are provided on the inner wall of the main body so as to protrude vertically and horizontally at a required interval.

The heating pipes 21, 22, and 23 are formed of a pipe having excellent thermal conductivity and corrosion resistance, and have a ceramic coating on the surface so that infrared heating can be used together. A plurality of radiating plates 20 are provided at a plurality of positions of the heating pipe 21 with their mounting angles set appropriately, thereby increasing the contact area with the molding material to improve the heating efficiency, and to improve the flow of the molding material. In this case, a stirring effect can be obtained.

The heating medium heated to a predetermined temperature by the temperature controller 2 is circulated and circulated inside the heating pipes 21, 22, 23 by connection to a pipe on the side of the temperature controller. The molding material can be dried by heating. The arrangement of the heating pipe 21 is not limited to a spiral, but may be a cross shape. Although not shown in the drawing, the outside of the main body where the heating pipe 22 is provided is covered with a heat insulating material together with the pipe.

A supply pipe 1 for dry air from a temperature controller also serving as a supply pipe for nitrogen gas is provided on the side of the material delivery cylinder 12.
5 is connected by providing a filter.
A very small amount of dry air or nitrogen gas (about 1 to 2 liters per minute) is fed into the main body to discharge moisture generated from the molding material from the exhaust pipe 13 of the lid member 14. Since the amount of dry air or nitrogen gas sent out through the supply pipe 15 is extremely small, contamination of contaminants does not pose a problem. In addition, the exhaust pipe 1
A vacuum pump may be connected to 3 for forced suction.

The supply of the molding material to the hopper 1 having the above-described configuration is performed by opening the cover member 14 in a fixed amount or, although not shown, a supply pipe is attached to the cover member 14 and the supply pipe is continuously supplied from the supply pipe. Do it.

The heating pipe 21 is buried in the molding material by the molding material in the hopper 1, and is dried by heating with a heating medium from the temperature controller 2. The heating is performed by the heated peripheral wall of the main body 10 and the stirring plates 3 and 3 inside the main body 10.
For this reason, even if the heating range of the internal heating pipe 21 is limited, the molding material is heated from the inside and outside by the heating from the outer peripheral wall side. Since it is enlarged by the plates 20, 20, even indirect heating by the heating pipes 21, 22, the heating efficiency is remarkably improved, and the heating becomes uniform, so that uneven drying hardly occurs. .

This heating and drying is maintained by a heating pipe 23 attached to the inside or the outer peripheral surface of the material delivery cylinder 12.
Since the molding material is fed into the heating cylinder in a heated state, it also serves as preliminary heating of the molding material during plasticization.

Therefore, each of the heating pipes 21, 22, 2
3, the heating medium of the temperature controller 2 is adjusted to an appropriate heating temperature and circulated and supplied, and the molding material in the hopper 1 is not affected by environmental changes such as temperature and humidity in a factory.
Heat drying can be carried out efficiently, and since the molding material and the heat medium are in a non-contact state, contamination caused when dry air is used as the heat medium is completely prevented.

Further, the heat medium is supplied to the heating pipes 21 and
By flowing from the lower part to the upper part of 23, an upper and lower temperature difference is eliminated by convection, and the temperature in the hopper is kept constant and stable, so that the temperature management becomes easy. For the temperature controller 2 as well, a ready-made mold temperature controller can be used, and not only stable supply of the heat medium but also reduction of the equipment cost can be achieved.

As described above, according to the present invention, the occurrence of molding failure due to contamination by dry air is prevented, and the molding failure due to moisture unevenness is prevented without drying unevenness. When molding optical system molded products and transparent products, it is not necessary to use a high-performance filter, and molding can be performed efficiently without frequent maintenance.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view schematically illustrating an embodiment of the present invention.

FIG. 2 is an explanatory cross-sectional view schematically illustrating an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hopper 2 Temperature controller 3 Stirring plate 10 Main body 11 Funnel-shaped lower part 12 Material delivery cylinder 13 Exhaust pipe 14 Cover member 15 Dry air supply pipe 20 Heat sink 21 Internal heating pipe 22 External heating pipe 23 Material delivery cylinder Heating pipe

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4F201 AC01 AH73 AK01 AK13 AL06 AL08 AL20 BA04 BN01 BN05 BN21 BN39 BQ01 BQ07 4F206 AC01 AH73 AK01 AK13 AL06 AL08 AL20 JA03 JA04 JA05 JA06 JA07 JF01 JF11 JF12 JF207 J04A AL06 AL08 AL20 KA01 KA11 KA17 KA19 KA20 KE06 KF01 KL41

Claims (3)

[Claims] 1. A hopper provided in a molding machine by connecting a lower end opening to a material input port of a heating cylinder, wherein the hopper has a cylindrical body having a funnel-shaped lower part and a material delivery cylinder connected to a lower part thereof. And a lid member having an exhaust pipe, and a heating pipe formed by flowing a heat medium from a temperature controller in a spiral shape inside and outside around a funnel-shaped lower portion of the main body and near an upper edge thereof, A contaminant hopper for a molding machine, comprising a plurality of agitating plates protruding vertically and horizontally at predetermined intervals on an inner wall of the body, and heating and drying a molding material from inside and outside a main body. 2. A heating pipe for circulating a heating medium is spirally disposed inside or on an outer peripheral surface of the material delivery cylinder, and a supply pipe of dry air from a temperature controller is provided on a side portion. The contamination-less hopper of a molding machine according to claim 1, wherein: 3. The contaminationless hopper of a molding machine according to claim 1, wherein a required number of heat radiating plates are provided at regular intervals on the heating pipe in the main body.