JPH04344090A - Through-flow rotary dryer - Google Patents

Abstract

PURPOSE:To prevent the adhesion and fusion of the material being dried and improve the durability of guide vanes by a method wherein, in a through-flow rotary dryer provided with guide vanes in its cylinder, the guide vane is formed of the metal plate covered partially with perfluorocarbon polymer. CONSTITUTION:In a through-flow rotary dryer having a number of guide vanes (louver) 4 in its rotary drum 1 wherein, between an entrance opening 2 for admitting the material to be dried into the rotary drum 1 provided at one end thereof and an exit opening 3 for carrying out the material provided at the other end thereof, the material is dried with a hot air delivered into the rotary drum 1 while being agitated by its rotation, the guide vane 4 is formed of the metal plate manufactured by a method comprising the steps of producing a number of fine cracks, pores, etc., in the surface of the metal by a mechanical treatment such as sand blasting or chemical treatment such as acid corrosion, opening the same by heat treatment, filling in the pores the cooled and contracted particles of perfluorocarbon polymer, effecting the fixation thereof and buff finishing the metal surface.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aerated rotary dryer. More specifically, the present invention relates to a drying device that prevents adhesion and fusion of materials to be dried and improves the durability of guide vanes (louvers).

0002

[Prior Art and Problems to be Solved by the Invention] An aerated rotary dryer is a type of rotary drum type drying device, in which a rotary drum is rotated at an appropriate speed, and the rotational force is used to feed the material into the drum. The material to be dried (for example, polyester resin) is stirred and hot air is blown into the cylinder to dry the material while moving it to the rear side (exit) of the cylinder and taking it out.

FIGS. 1 and 2 show an aeration rotary drying apparatus having guide vanes (louvers) inside a cylinder, in which (1) is a rotating drum, (2) is a material input port, and (2) is a rotary drum.
3) shows the product outlet, and (4) shows the guide vane (louver). In such an apparatus, drying conditions can be appropriately set between the input side of the material to be dried and the output side of the product, and since the holdup is 20 to 30% of the drum volume, large quantities can be processed.

However, conventional SUS340, SU
S316, in drying equipment that has guide vanes such as hard chrome plating, if the material to be dried is a substance that easily fuses or sticks, such as a low melting point copolymer, the material to be dried will adhere to the guide vanes, reducing drying efficiency. becomes worse, and eventually continuous processing becomes impossible. In addition, with guide vanes that have been simply treated with a non-adhesive treatment such as Teflon coating, the surface treatment agent will gradually wear out.
Improvements were required because wear particles were mixed into the product.

[0005]

[Means for Solving the Problems] In view of the above-mentioned problems, the present inventors have made extensive studies and have found that by using guide vanes having a specific configuration, it is possible to prevent the materials to be dried from fusing and adhesion, and to guide the It was discovered that the durability of the blades was also dramatically improved, and the present invention was completed. That is, the gist of the present invention is an aerated rotary dryer having a guide vane in a cylinder, characterized in that the guide vane is composed of a metal plate whose surface is partially coated with a perfluorinated carbon polymer. It consists of an aeration rotary dryer.

The present invention will be explained in more detail below. The invention requires the use of a metal plate whose surface is partially coated with a perfluorinated carbon polymer as a guide vane. Such metal plates are produced by, for example, subjecting the metal surface to a mechanical treatment such as fluid polishing or sandblasting, or a chemical treatment such as acid corrosion, resulting in a large number of microscopic fissures, pores or fissures on or within the metal surface. It can be obtained by making, enlarging by heat treatment, filling the micropores with perfluorinated carbon polymer particles that have been cooled and contracted, and then fixing and buffing the surface.

[0007] The metal plate is normal SUS304, SUS31
Metals such as No. 6 are used, but those whose surfaces have been hardened by chromium plating are particularly preferred.

[0008]

[Operation] Since the present invention uses guide vanes having a special surface composition, it is possible to simultaneously improve the contradictory properties of non-adhesive effect and durability.

[0009]

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. Example (Preparation of guide vanes) A steel plate was cleaned, plated with hard chrome, and then polished. Then surface treated in an acid bath,
After forming micropores on the chromium plated surface, it was neutralized, dried, and heated to about 205° C. to enlarge the micropores. Approximately 10 μm, previously frozen at approximately -74°C, is inserted into the micropores.
polytetrafluoroethylene fine particles were deposited little by little. After sufficient polytetrafluoroethylene fine particles were introduced into the micropores, the excess particles were removed, and the plate was returned to room temperature and fixed. The surface of the obtained metal plate was polished and buffed, and then processed into a predetermined size and shape to produce guide vanes. (Drying of material) In a drying apparatus equipped with the guide vanes, a copolymer (polyethylene terephthalate copolymerized with 20 mol% isophthalic acid: melting point 210°C, Tg 60°C) was crystallized at 130°C for 2 hours, and then It was dried at ℃ for 2 hours.

[0010] At this time, the copolymer did not fuse in the drying rotating drum, and the guide vanes did not wear out at all even after 2000 hours of continuous operation. Comparative Example 1 When the copolymer used in the example was dried using SUS304, hard chrome-plated SUS304, and a copper plate as guide vanes, in all cases there was no fusion between the copolymers and no copolymer Fusion to the guide vane occurs,
Continuous drying was not possible.

Comparative Example 2 A metal plate whose surface was coated with Teflon was used as a guide vane, and drying was carried out in the same manner as in the example, but the Teflon was worn out and mixed into the copolymer.

0012

According to the drying apparatus of the present invention, adhesion and fusion of materials to be dried can be prevented, and it can also be used as a crystallization apparatus for copolymers. Furthermore, since the guide vanes are durable, it can be operated continuously for long periods of time, and its industrial value is high.

[Brief explanation of drawings]

FIG. 1: Schematic diagram of the aerated rotary dryer of the present invention

[Figure 2] Cross-sectional schematic diagram

[Explanation of symbols]

1 Rotating drum 2 Dry material input port 3 Product outlet 4 Guide vane (louver)

Claims (1)

[Claims] 1. An aeration rotary dryer having a guide vane in a cylinder, characterized in that the guide vane is composed of a metal plate whose surface is partially coated with a perfluorocarbon polymer. Aerated rotary dryer.