JP2000297983A - Steam drying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam drying device, capable of drying a matter to be dried in a short period of time without any mottle and capable of contracting the size of the device while economical and capable of contriving the improvement of safety of the device as well as the reduction of the cost of the device. SOLUTION: After evaporating vapor solvent by heating and evacuating, the inside of a drying tank is evacuated to increase the degree of vacuum further in order to remove the vapor solvent, adhered to the matter to be dried 18. The vapor solvent supplying tank 13 is equipped with a condensing coil 13a to serve both for the recovery tank of the vapor solvent. The noncombustible vapor solvent, having no flash point, is employed as the vapor solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam drying apparatus for drying an object to be dried, such as metal, plastic, and glass parts, using a solvent vapor.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for drying an object to be dried such as metal, plastic, glass parts, etc., an apparatus for rotating an object to be dried at a high speed and blowing off moisture on the surface by centrifugal force to dry the object to be dried. Alternatively, a device for drying the object to be dried by blowing hot air onto the object to be dried is known,
In addition, there is a steam drying apparatus for drying an object to be dried by heating the object to be dried with a solvent vapor, whereby a very clean dry surface can be obtained. In this steam drying apparatus, the inside of the drying tank is set to a reduced pressure during drying in order to reduce the vaporization temperature of the solvent, reduce the size of the heat source for vaporization, and prevent the material to be dried from raising the temperature.

[0003]

However, in the conventional steam drying apparatus, when the object to be dried is heated by the solvent vapor, the heat is taken away by the object to be dried and the solvent vapor liquefies and adheres to the object to be dried. However, since a means such as natural leaving is used to completely remove this, there is a drawback that the drying time is prolonged. In addition, since the tank for supplying the vapor solvent and the tank for condensing the solvent vapor and recovering the vapor solvent were separate, there was a drawback that the size of the apparatus became large. Furthermore, when using flammable solvents, it is necessary to use explosion-proof parts or materials for the safety of the equipment.In addition, when removing the dried material after drying, In order to prevent the vapor from being emitted to the outside, it is necessary to adopt a structure in which an inert gas is introduced into the drying tank to recover the pressure, and there is a disadvantage that the cost of the apparatus is increased.

[0004] The present invention has been made in view of the above points,
A first object is to provide a steam drying apparatus capable of shortening the drying time. A second object of the present invention is to provide a steam drying apparatus capable of reducing the size of the apparatus.
Further, a third object of the present invention is to provide a steam drying apparatus capable of improving the safety of the apparatus and reducing the price of the apparatus.

[0005]

According to the steam drying apparatus of the present invention, after the object to be dried is carried into the drying tank, the steam solvent injected into the drying tank from the steam solvent supply tank is heated.
The vapor solvent is vaporized by depressurizing the inside of the drying tank with a vacuum pump, and after a certain period of time under a certain reduced pressure, the inside of the drying tank is increased once or more times by the vacuum pump so that the degree of vacuum is increased. Is reduced in pressure. In this steam drying apparatus, the steam solvent supply tank in which a condensation coil for returning the solvent vapor to the vapor solvent is disposed in the tank between the drying tank and the vacuum pump is provided. Also, a nonflammable vapor solvent having no flash point is used.

According to the steam drying apparatus of the present invention, the object to be dried is heated by the vapor of the vapor solvent at the initial pressure reduction, and the vapor colliding with the object to be dried is deprived of heat by the object to be liquefied to be liquefied. Attaches to dry matter. After that, if the pressure is further reduced and the degree of vacuum is increased, the vaporization temperature of the vapor solvent decreases,
The vapor solvent adhering to the object to be dried is vaporized again, and the object to be dried is dried in a short time without unevenness. Further, by using a vapor solvent supply tank having a condensing coil for returning the vapor to the vapor solvent in the tank, the vapor solvent supply tank also serves as a vapor solvent recovery tank, so that the size of the apparatus can be reduced. The condensed and recovered vapor solvent can be used repeatedly. Furthermore, by using a nonflammable vapor solvent without a flash point, even if steam leaks to the outside of the device, it will not be ignited by external fire or heat, thus improving the safety of the device. In addition, since it is not necessary to use explosion-proof parts or materials, the price of the apparatus can be reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a steam drying apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG.
1 is a configuration diagram showing an embodiment of a steam drying device of the present invention. This steam drying device includes a drying tank 11, a pipe heater 1
2, a vapor solvent supply tank 13, an air control first control valve 14, a vacuum pump 15, an oil mist trap 16,
It comprises a second control valve 17.

[0008] The drying tank 11 has a lid 11a on the upper surface, from which the material to be dried 18 is carried in and taken out.
Further, the drying tank 11 has an oil indirect heater 11b at a lower portion, and heats the vapor solvent supplied into the tank by the oil indirect heater 11b. The oil indirect heater 11b is heated by the pipe heater 12.

The vapor solvent supply tank 13 is connected to the drying tank 11 by a pipe 19 and supplies the contained vapor solvent 22 to the drying tank 11. On the pipe 19, the drying tank 1
A first control valve 14 for air control is provided to keep the amount of vapor solvent supplied to 1 constant. The vapor solvent supply tank 13 is connected to an upper part in the drying tank 11 by a pipe 20, and the solvent vapor in the drying tank 11 is supplied.
A condensation coil 13a for circulating cooling water is provided in the vapor solvent supply tank 13, and the solvent vapor supplied from the drying tank 11 is cooled by the condensation coil 13a and returned to the vapor solvent. Here, a nonflammable vapor solvent having no flash point is used as the vapor solvent, and specifically, hydrofluorocarbon or hydrofluoroether.

The vacuum pump 15 is connected to the evaporation solvent supply tank 13 by a pipe 21, and depressurizes the inside of the drying tank 11 through the evaporation solvent supply tank 13. Piping 2
On 1, a second control valve (leak valve) 17 for controlling the pressure reduction in the drying tank 11 by the vacuum pump 15 is provided.
Further, an oil mist trap 16 is provided with the vacuum pump 15 in order to collect the solvent vapor that has not been collected by the condenser coil 13a of the vapor solvent supply tank 13 and has flowed to the pipe 21 side.

In the above-described steam drying apparatus, the drying step of the object to be dried 18 is performed as shown in the flowchart of FIG. That is, first, the lid 11a is opened and the object 18 to be dried is carried into the drying tank 11 (step S1), and the lid 11a of the drying tank 11 is closed (step S2). Next, a certain amount of nonflammable vapor solvent having no flash point is injected into the drying tank 11 from the vapor solvent supply tank 13 through the first control valve 14 (step S3). Thereafter, the vacuum pump 15 is operated (step S4), and the pressure in the drying tank 11 is reduced through the vapor solvent supply tank 13.
At this time, by opening the second control valve (leak valve) 17, the drying tank 11 is kept under a constant reduced pressure (20 to 100 Torr).
The pressure is reduced to r). Simultaneously with this pressure reduction, the pipe heater 12
Heats the indirect heater 11b, and heats the vapor solvent in the drying tank 11 by the indirect heater 11b. As a result, the vapor solvent in the drying tank 11 is heated by the indirect heater 11b,
It is vaporized by the reduced pressure by the vacuum pump 15 and becomes steam (step S5).

The vaporized solvent (solvent vapor) is
It is drawn from the upper part of the drying tank 11 to the vapor solvent supply tank 13 by the vacuum pump 15 (step S6). On the way, in the drying tank 11, the solvent vapor
8 is heated to evaporate the water on the object 18 to be dried. In addition, the steam that has collided with the object to be dried 18 is deprived of heat by the object to be dried 18 and liquefied and adheres to the object to be dried 18. Further, the vapor drawn into the vapor solvent supply tank 13 is cooled and liquefied by the condensing coil 13a, and is collected again in the vapor solvent supply tank 13. Further, the vapor not liquefied by the condensing coil 13a passes through the vacuum pump 15 and is liquefied and collected by the oil mist trap 16.

In such a state, for a certain period of time (for example, 3 minutes)
After the operation, the second control valve (leak valve) 17 is closed to remove the vapor solvent adhering to the object to be dried 18 (step S7). Then, the drying tank 11 is moved by the vacuum pump 15.
The pressure inside is further reduced to 3 to 5 Torr. Then, since the vaporization temperature of the vapor solvent is lowered, the vapor solvent attached to the object to be dried 18 is vaporized again and removed from the object to be dried 18 (step S8). As a result, the article to be dried 18 dries in a short time without unevenness. In addition, the vapor solvent which has become the vapor again is also supplied to the vapor solvent supply tank 13 and the oil mist trap 1.
The liquefied liquid is collected in step 6 (step S9).

As described above, according to the above-mentioned steam drying apparatus, an object to be dried can be dried without unevenness in a short time. Further, since the vapor solvent supply tank 13 having the condenser coil 13a for returning the vapor to the vapor solvent is provided in the tank, the vapor solvent supply tank 13 also serves as a recovery tank for the vapor solvent, so that the size of the apparatus is reduced. In addition, the vapor solvent condensed and recovered can be used repeatedly, which is economical. Furthermore, by using a nonflammable vapor solvent without a flash point, even if steam leaks to the outside of the device, it will not be ignited by external fire or heat, thus improving the safety of the device. In addition, since it is not necessary to use explosion-proof parts or materials, the price of the apparatus can be reduced.

In the above embodiment, the pressure is reduced once after the initial pressure reduction so as to increase the degree of vacuum. However, the pressure reduction may be performed a plurality of times by gradually increasing the degree of vacuum.

[0016]

As described above in detail, according to the steam drying apparatus of the present invention, the object to be dried can be dried in a short time without unevenness, the size of the apparatus can be reduced, and the condensation can be performed. The recovered vapor solvent can be used repeatedly, which is economical. Further, the safety of the apparatus can be improved and the price of the apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a steam drying device according to the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Drying tank 11a Lid 11b Indirect heater 12 Pipe heater 13 Vapor solvent supply tank 13a Condensing coil 14 First control valve 15 Vacuum pump 16 Oil mist trap 17 Second control valve 18 Dry matter 19-21 Pipe 22 Vapor solvent

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Kazumasa Sugimoto, 2-3-1, Shibasaki, Chofu-shi, Tokyo Inside Shimada Chemical Industry Co., Ltd. (72) Etsuro Kitagawa 2-3-1, Shibasaki, Chofu-shi, Tokyo Tokyo Shimada (72) Koji Yokotagawa, Inventor Koji Yokotagawa, 2-3-1, Shibasaki, Chofu-shi, Tokyo Tokyo, Japan Shikada Chemical Co., Ltd. (72) Kazuhiro Takishita 2-1-1, Shibasaki, Chofu-shi, Tokyo Rika Shimada 3L113 AA01 AB02 AC01 AC24 AC45 AC46 AC50 AC63 AC67 AC75 AC78 AC79 AC86 AC90 BA04 CA16 CB16 CB23 CB34 CB35 DA06 DA10 DA14 DA21 DA24

Claims (6)

[Claims] 1. After the object to be dried is carried into the drying tank, the vapor solvent injected into the drying tank from the vapor solvent supply tank is heated, and the inside of the drying tank is depressurized by a vacuum pump. A steam drying apparatus comprising: evaporating a solvent; and after elapse of a certain time under a certain reduced pressure, reducing the pressure in the drying tank by the vacuum pump once or more times so as to increase the degree of vacuum. 2. The steam drying apparatus according to claim 1, wherein the initial pressure is set at 20 to 100 Torr, and then the pressure is further reduced. 3. The vapor solvent supply tank provided with a condensation coil for returning solvent vapor to a vapor solvent in the tank between the drying tank and the vacuum pump. The steam drying apparatus according to item 1. 4. The steam drying apparatus according to claim 1, wherein a nonflammable steam solvent having no flash point is used. 5. The steam drying apparatus according to claim 4, wherein the nonflammable vapor solvent is hydrofluorocarbon or hydrofluoroether. 6. A drying tank provided with an indirect heater for heating the supplied vapor solvent, a drying tank into which an object to be dried is carried in, a heater for heating the indirect heater, and a flash point supplied to the drying tank. A vapor solvent supply tank having a condensing coil for supplying a solvent vapor from the drying tank and returning the solvent vapor to the vapor solvent, A first control valve for controlling the evaporation solvent supplied to the drying tank to a constant value, a vacuum pump for reducing the pressure in the drying tank through the evaporation solvent supply tank, and controlling the pressure reduction in the drying tank by the vacuum pump. A second control valve, and a trap for collecting the solvent vapor that could not be recovered by the condensation coil. After the drying object is loaded into the drying tank, the pressure in the drying tank is reduced to a constant pressure by the vacuum pump. 2. The steam drying apparatus according to claim 1, wherein the pressure is reduced so that the degree of vacuum is increased once or more times after a predetermined time has elapsed under the constant pressure reduction.