JPS623667Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a jacket structure disposed on the outer wall of a transport pipe of a flash dryer.

Conventional technology Vinyl chloride resin, vinylidene chloride resin or
When drying solids that easily decompose or fuse at the drying temperature, such as ABS and MBS resins, using a flash dryer, if the drying temperature is higher than the decomposition temperature of the solid or higher than the fusion temperature, the solid often adheres to the inner wall of the transport pipe. It may stick. If solids adhere to the can walls, the drying ability will be reduced and the tubes will become clogged, and if exposed to high temperatures for long periods of time, they will become colored, and this will often peel off during operation and enter the product, leading to a decline in quality. . In order to avoid this, in order to keep the gas phase part of the flash dryer, such as the inner wall of the transport pipe or collector, at a temperature lower than the drying temperature, a cooling jacket is provided on the outer wall of the gas phase part, and water, etc. is poured into the jacket. A method for preventing solids from adhering to the pipe wall has already been developed (see Japanese Patent Publication No. 43-6438).

By maintaining the inner wall of the transport pipe at a temperature lower than the drying temperature in this way, the adhesion of solids to the transport pipe, etc. was greatly reduced, and the problem of adhesion to the pipe wall of the flash dryer was temporarily solved, but the implementation of this method Another problem with this process was that cracks appeared in the transport pipes. That is, in the conventional apparatus shown in FIG. 1, 1 is a transport pipe of a flash dryer, and is connected by upper and lower flanges 2 and 3 to flanges 3' and 2' of another transport pipe, respectively. There is. 6 is a mantle disposed between the flanges;
This mantle is provided with a water inlet 4 and a water outlet 5, and water is circulated within the mantle by an external pump (not shown). Wet resin and hot air are supplied from the lower part of the tube, are dried while passing through the tube, and are collected in a collector. In this case, it is difficult to cool the area around the flange where there is no jacket, so adhesion cannot be prevented, and a space 51 is created above the water section 61 in the jacket 6 at the outlet section 5, creating a gas-liquid contact surface. When this gas-liquid contact surface exists in the jacket, many cracks often occur in the circumferential direction of the transport pipe at the contact surface after long-term operation. This crack is probably caused by point contact at the gas-liquid contact surface, stress corrosion cracking, and dissolved oxygen, chloride ions,
This is accelerated by temperature and other factors, and is especially problematic when used under harsh conditions at high temperatures, such as in a flash dryer. Such cracks cannot be prevented by changing the material of the transport pipe, and even if high-quality corrosion-resistant materials are used, the transport pipe must be replaced after a certain period of time. It was hot.

Means for Solving the Problems In this invention, in order to eliminate the drawbacks of the conventional method, a mantle is provided between the upper and lower flanges of the transport pipe, a water inlet part and an outlet part are provided, and a water outlet part is provided. The tube passes through the upper flange, thereby preventing the presence of a gas phase within the jacket and preventing cracks in the tube.

Embodiment FIG. 2 shows an embodiment of this invention, in which a jacket 6 is disposed between the upper and lower flanges of the transport pipe 1 over its entirety. That is, the upper end of the mantle 6 is in close contact with the flange 2, and the lower end is in close contact with the flange 3, respectively. The mantle 6 has a water inlet 4 and an upper flange 2.
A water outlet portion 5 is provided which penetrates the inside and flows out to the outside. In this invention, since the water outlet section 5 passes through the upper flange 2, the inside of the mantle 6 is filled with water 61, and there is no gas phase section. Note that the water outlet part is not limited to the form shown in the example.
It can be in any form. The structure of this invention has the advantage that cracks in the tube can be prevented because there is no gas phase inside the jacket, and that solids can also be prevented from adhering to the flange because the inside of the flange is also cooled to some extent.

When the amount of water circulating is small, it is sufficient to have only the water outlet section 5 passing through the flange, but when the amount of water circulating is large, an additional water outlet section 5' may be provided at the upper part of the mantle between the upper and lower flanges. Good too. It is appropriate to provide the water inlet portion 4 at a relatively lower portion of the mantle disposed between the flanges 2 and 3, preferably at the lowest portion, in order to eliminate water accumulation. It is preferable that the material of the mantle and the material of the transport pipe be the same, since no stress is applied during operation. Further, in the case of this invention, since the jacket is disposed in close contact with the flange of the transport pipe and extends between them, it is desirable to provide an expansion bellows 7 to relieve stress caused by thermal expansion and contraction.

A flash dryer using a stainless steel transport pipe having a jacket structure as shown in FIG. 2 was used to continuously dry the wet vinylidene chloride resin under the conditions shown below.

Vinylidene chloride resin supply rate
800Kg/Hr (drying amount) Vinylidene chloride resin moisture to be dried 18-25% Supply hot air temperature 150℃ Dried product moisture 0.5-2.0% Mantle cooling water temperature Inlet 10℃ Same as above Outlet 60℃ Almost no water is in the transport pipe of the dryer No polymer adhesion was observed, and no cracks were formed in the tube, and it could be used without any abnormality after more than 5 years of operation.

On the other hand, in the conventional structure of the transport pipe shown in Figure 1, polymer adhesion was observed near the flange of the pipe, and numerous cracks were observed in the circumferential direction of the transport pipe, which corresponds to the air-liquid contact surface of the jacket. , the transport pipes had to be replaced every six months to a year.

Effects Since this invention has such a structure, no gas phase is generated within the jacket, preventing cracks in the pipe, and since the inside of the flange is also cooled to a certain extent, it is possible to prevent solids from adhering to the flange.

[Brief explanation of the drawing]

FIG. 1 shows a conventional jacket structure for a flash dryer transport pipe, and FIG. 2 shows a jacket structure according to the invention. Explanation of symbols, 1...Transport pipe, 2, 3...Upper and lower flanges, 4...Water inlet section, 5...Water outlet section, 6
...Cloak, 7...Expansion bellows.

Claims (1)

[Scope of utility model registration request] In a flash dryer for solids that easily decompose or fuse at the drying temperature, a cooling jacket is provided on the outer wall of the gas phase portion of the flash dryer to maintain the inner wall of the gas phase portion at a temperature lower than the drying temperature. A mantle 6 disposed between the upper and lower flanges 2 and 3 of 1 is provided with a water inlet part 4 and a water outlet part 5 that penetrates the inside of the upper flange 2 and flows out to the outside. A flash dryer transport pipe mantle characterized by: