JPS61107082A - Drier - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an apparatus for drying powder and granular materials under full blast heat in a vacuum state.

(Prior Art) Apparatuses for stirring, mixing, and drying powder and granular materials can be roughly divided into two types: a rotating container type and a fixed container mixing type.

Figure 2 shows the entire V-type mixer 1 as a representative of the container rotating type, and all materials are charged from the two charging ports 2 at the top.
The method is to discharge from the intersecting part 5, but the softening bath may be sticky or meltable when heated. Since it is difficult to apply to those with c.c., a fixed container mixing type is often used.

Figure 3 shows a so-called narrator type mixer, in which a screw 4 installed inside the container 1 rotates around its axis and mixes all the powder and granules. For example, it is also possible to use it in a vacuum dryer that is completely equipped with a jacket (for example, a jacket through which high-temperature heat transfer oil flows) and is maintained in a vacuum state. However, it is difficult to seal the two shafts of rotation and revolution, making it impossible to operate under high vacuum. In addition,
In the figure, 5 is a discharge port.

Fig. 4 shows a fountain mixer with a screw 4 installed in the center of the container 1, but when using the wall heating method in a vacuum dryer, heat transfer is poor and the mixer is too large to be applied to materials that stick to the inner wall. There are drawbacks to becoming

(Problems to be Solved by the Invention) The inventors investigated an apparatus for drying polyester resin pellets containing internal moisture of 1,000 to 2,000 ppm to a residual moisture of 10 ppm or less, and found that heating drying under normal atmospheric pressure does not Since the degree of polymerization decreases significantly due to hydrolysis, making it impractical, we conducted extensive research into a device that heats and dries under vacuum. Polyester has a crystallization temperature of about 110°C, so when it is heated, it becomes sticky around this point, and by attaching a layer to the heated surface, it is maintained at a high vacuum of around 1 Torr and pellets are formed. - The purpose is to develop a highly efficient X-air drying device that does not create a layer on the wall and does not create any stagnation inside the container.

(Means for solving all problems) The present invention has a ribbon-type stirring blade installed in the center of the interior of a conical vertical fixed container, making it possible to completely prevent leakage from the rotating shaft and easily maintaining a high vacuum. This is characterized by the fact that the pellets move all the way up on the peripheral wall and down at the center of the inside, which allows for efficient heat exchange, and also completely eliminates adhesion to the wall and stagnation. .

That is, the present invention relates to a drying apparatus for thermally drying 71 fl of powder or granular material (r is.

The present invention can be advantageously applied as a mixing device and a drying device for powder and granular materials.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIG.

FIG. 1 shows an example in which the present invention is applied to a vacuum drying apparatus for polyester pellets. In FIG. 1, 1 is a vertical conical dryer main body, 2 is a stirring shaft, and a ribbon-shaped stirring blade 3 is fixed to this. Note that this stirring shaft 2
It is preferable to provide it so that it can slide up and down.

4 is a jacket through which the heating medium flows, and an inlet nozzle 5
, has 6 outlet nozzles. 7 is a charging port for raw material pellets;
Reference numeral 8 denotes a product discharge valve, and the valve body 9 is entirely driven by an air cylinder 11. Further, to prevent leakage from the valve stem 12, it is sealed with a metal bellows 10. 13 is a vacuum valve, 14 is an exhaust port connected to a vacuum source (not shown), and 15.18 Fi seal mechanism 16 is an electric motor 1 for stirring.
This is a pedestal that supports 7.

(Operation) Raw material pellets are charged into the dryer 1 from the charging lower. The dryer 1 is heated in advance to a predetermined temperature by flowing the heat medium from the fully filled nozzle 5 to the outlet nozzle 6, and then the stirring blade 5
The motor 17 also rotates at a predetermined rotation speed.

The discharge valve 8 is also kept closed, and after the raw materials have been input,
After the charging lower is completely closed, the mixture is vacuumed to about 1 Torr and stirred and mixed for a predetermined period of time to dry.

After drying, the system is released to full atmospheric pressure, the product discharge valve 8 at the bottom is opened, and the product is collected in a tank (not shown) outside the system.

(Effects) As an effect of arranging the ribbon-shaped stirring blades in the vertical conical mixing tank, it is possible to prevent the raw materials from adhering to the heating wall surface, and the heat transfer coefficient is increased.

(2) The flow pattern is such that the raw material σ rises up the wall surface and descends completely at the center, and the cross-sectional area increases as it goes up, promoting particle mixing in the radial direction and dramatically increasing the heat transfer coefficient compared to the conventional fountain type. becomes larger.

(3) There are no sluggish areas within the layer,
There is no variation in product quality.

(41) Because of its conical shape, it is easy to discharge the product, and there is no contamination between different types of products when processing all kinds of raw materials.

(5) Compared to the Narrator type, this is a uniaxial seal, and regular mechanical seals can be used to maintain true walls.

(6) By moving the stirring shaft up and down, the gap between the ribbon blade and the wall surface can be easily adjusted.

Therefore, even materials with extremely strong N-binding properties can be processed, expanding the field of application.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the apparatus of the present invention, and FIGS. 2 to 4 are schematic diagrams showing various conventional drying apparatuses. Sub-Agent 1) Meifu Agent Ryo Hagiwara - JP-A-1-107082 (3) Figure 2 Figure 3

Claims (1)

[Claims] What is claimed is: 1. A drying device for heating and drying powder and granular materials under vacuum conditions, characterized in that the main body has a vertical conical shape, and a plurality of ribbon-shaped stirring blades are provided inside.