JPH07208859A - Vacuum drying device - Google Patents

Abstract

PURPOSE:To obtain a vacuum drying device wherein a drying efficiency is raised, by heating a material to be dried with a good efficiency and uniformly. CONSTITUTION:In a vacuum drying device having a vessel wherein an inner section can be airtight, an exhaust means 43 executing an exhaust of an inside of the vessel, a heating device heating an inside of the vessel, and a centrifugal dehydration mechanism 25 equipped with a rotating body 24 accommodating a material 50 to be dried, and set rotatably in the vessel, an agitating blade 26 is arranged in the rotating body 24. By this, a hot air hits against all over the material to be dried, the material to be dried is uniformly heated, and a dehydrating efficiency becomes high, by executing an agitation in the vessel through producing an air current in the vessel from a vicinity of the material to be dried when a centrifugal dehydration is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum drying device for drying precision electronic parts, metal parts, plastic molded parts and the like after cleaning.

[0002]

2. Description of the Related Art Conventionally, Freon-113 or 1,1,1-for cleaning precision electronic parts, metal parts, plastic molded parts, etc.
Although cleaning agents such as trichloroethane have been used, in recent years, due to problems of ozone layer depletion and effects on the human body, the use of the above cleaning agents has been limited, and cleaning with alternative cleaning agents is being started. Water-based, alcohol-based or hydrocarbon-based ones are used as the alternative cleaning agents. Especially, in the case of the water-based cleaning agents, Freon-113, 1,1,
Unlike 1-trichloroethane, there is a problem that a rinsing process with pure water or city water is required, so that the subsequent drying process takes time.

As a drying device used in the drying process, a vacuum drying device is often used. Among them, in order to shorten the time of the drying process, the vacuum drying device having a heating means for the material to be dried and a centrifugal dehydration mechanism has been developed for the purpose of minimizing the adhesion of water.

An example of this type of vacuum dryer is shown in FIG. This vacuum drying device includes a tank 10 and
The heater 20, a centrifugal dehydration mechanism 30, and a vacuum pump 40 are roughly configured. The tank 10 is composed of a tank main body 11 in which a basket member 34 made of a metal net or the like for accommodating a material to be dried is installed, and an openable / closable sealing lid 12. The tank 10 is hermetically sealed with these tank main bodies 11. A space 17 is formed by the lid 12. At the bottom 11a of the tank body 11,
A drain pipe 13 for discharging water to the outside of the tank 10 is connected, and the drain pipe 13 is provided with a drain valve 14. A leak pipe 15 for supplying a leak gas into the bath is connected to the bath body 11, and a leak valve 16 is provided in the leak pipe 15. The heater 20 heats the inside of the tank, and is provided above the basket member 34 accommodated in the tank 10, for example.

The centrifugal dehydration mechanism 30 is composed of a drive motor 31 outside the tank 10, a rotating shaft 32 rotated by the drive motor 31, and a rotating body 35 connected to the rotating shaft 32 inside the tank 10. The rotary body 35 is composed of a turntable 33 and a basket member 34 for containing a material to be dried to which moisture is attached. In the centrifugal dehydration mechanism 30, when the drive motor 31 is driven, the rotary shaft 32 rotates, and the turntable 33 also rotates together with the rotary shaft 32. Therefore, the basket member is placed on the turntable 33. If 34 is fixed, this basket member 34 also rotates. The vacuum pump 40 is for exhausting gas in the tank, and the vacuum pump 40 and the tank body 11 are connected by an exhaust pipe 41. An exhaust valve 42 is provided in the exhaust pipe 41.

In order to dry the moisture attached to the material to be dried using such a vacuum drying device, first, the sealing lid 12,
The drain valve 14, the leak valve 16, and the exhaust valve 42 are closed to keep the tank 10 airtight. Then the heater 2
At 0, the space 17 in the tank 10 is heated. Next, the airtight lid 12 is opened, and the basket member 34 in which the material to be dried 50 to which moisture is attached is placed is fixed on the turntable 33. Next, after closing the sealing lid 12 and opening the drain valve 14, the drive motor 31 is driven to drive the basket member 34.
Spin to spin-dry. The water dehydrated here is drained to the outside through the drain pipe 13 as drainage. Thereafter, the drain valve 14 is closed, the exhaust valve 42 is opened, the vacuum pump 40 is operated, the gas in the tank 10 is exhausted from the exhaust pipe 41, and the space 10 is brought to a high vacuum state. Residual water adhering to is evaporated and dried.
The evaporation of water mainly uses the heat capacity of the material to be dried rather than radiant heat, and the temperature of the material to be dried decreases as it dries. After that, the exhaust valve 42 is closed, the leak valve 16 is opened, and the atmosphere is introduced into the tank 10 from the leak pipe 15 to break the high vacuum state and to close the closed lid 12.
And the object 50 to be dried is taken out together with the basket member 34.

[0007]

However, in the above-mentioned conventional vacuum drying apparatus, even if centrifugal dehydration is performed,
There were cases where some parts were not dehydrated. Therefore, it may be necessary to perform vacuuming for a long time in order to uniformly dry the moisture attached to the material to be dried 50, and it has not always been possible to achieve the purpose of shortening the time of the drying process. Further, if the material to be dried is unevenly distributed in the basket due to centrifugal dehydration, it is difficult to transfer heat to the portion that has entered the inside of the material to be dried, and it is also difficult to sufficiently dry it. Furthermore, if the rotation speed is increased in order to enhance the dehydration effect of centrifugal dehydration, the material to be dried may be damaged.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a vacuum drying apparatus in which heat is efficiently and evenly supplied to an object to be dried so that the drying efficiency is improved.

[0009]

A vacuum drying apparatus of the present invention contains a tank whose inside is airtight, an exhaust means for exhausting the inside of the tank, a heating means for heating the inside of the tank, and an object to be dried. In addition, in a vacuum drying apparatus having a centrifugal dehydration mechanism having a rotating body rotatably installed in the tank, the rotating body is provided with stirring blades.

At this time, it is preferable that the rotating body comprises a turntable and a basket member placed on the turntable.

The vacuum drying apparatus according to a third aspect of the present invention is characterized in that the turntable has a bottom plate, and the stirring blades are arranged on the bottom plate.

In a vacuum drying apparatus according to a fourth aspect of the present invention, the turntable includes an annular peripheral wall and a stirring blade radially provided from a central portion of the peripheral wall toward the peripheral wall. It is what

[0013]

In the vacuum drying apparatus of the present invention, the stirring blade also rotates with the rotation of the rotor during centrifugal dehydration, and the rotating stirring blade generates an air flow in the tank to stir the inside of the tank. Then, since hot air is transmitted to every corner of the material to be dried, the material to be dried is evenly heated. Therefore, the dehydration efficiency is improved and the time of the drying process can be shortened. In addition, since the stirring blades force hot air to the material to be dried, even if the material to be dried has a complicated shape, or if the material to be dried is biased, it must be heated to every corner. Therefore, the dehydration efficiency can be improved.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an embodiment of a vacuum drying apparatus of the present invention, in which a tank 19 that can hermetically seal an internal space, an exhaust unit 43 that exhausts the inside of the tank 19, and a heating unit that heats the inside of the tank 19 are provided. 21 and a centrifugal dehydration mechanism 25 including a rotating body 24 rotatably installed in the tank 19, and is configured roughly. The tank 19 is composed of a tank body 18 and a lid 12 placed on the tank body 18, and makes the inside airtight. The exhaust means 43 exhausts the inside of the tank 19 kept airtight,
The inside is evacuated, and is roughly configured by a vacuum pump 40, an exhaust pipe 41 connecting the inside of the tank and the vacuum pump 40, and an exhaust valve 42 provided in the exhaust pipe 41. Heating means 2
Reference numeral 1 is for heating the inside of the tank 19, and various heaters such as heating wires are used. In this example, the heating means 21 is embedded inside the tank main body 18 itself, but the heating means 21 is not limited to this as long as the inside of the tank 19 can be heated. For example, the heating means 21 is arranged above the rotating body 24 in the tank 19. It doesn't matter. However, as shown in the figure, by providing the inside of the tank main body 18, the material to be dried can be heated uniformly from the surroundings, which is more preferable. In this configuration, the inner wall surface of the tank body 18 is preferably made of a material having a high thermal conductivity so that the heater 21 can efficiently heat the heater. Also, in order to improve the heating efficiency, the heater is used. It is desirable to provide a heat insulating material on the outer portion of the tank body 18 to which 21 is attached. The centrifugal dehydration mechanism 25 includes a rotating body 24, a drive motor 31 that generates a driving force for rotating the rotating body 24,
A rotary shaft 32 that transmits the rotational force of the drive motor 31 to the rotating body 24 is roughly configured. The rotating body 24 is composed of a turntable 23 and a basket member 22 for containing a material to be dried.

In the vacuum dryer of this embodiment, the bottom plate 29 of the turntable 23 has a plurality of stirring blades 26, 26,
... is provided. In this example, as shown in FIG.
The stirring blade 26 is composed of a pedestal 28 attached to the turntable 23 and a wing portion 27 erected on the pedestal 28. By rotating the turntable 23,
There is an action of generating an air flow in the tank 19 to stir the gas in the tank 19. In this embodiment, the stirring blade 26 is composed of a pedestal 28 and a blade 27 as shown in FIG. 2, but the present invention is not limited to this, and the inside of the tank 19 is rotated by the rotation of the turntable. Obviously, anything that can be stirred may be used. Further, the number of the stirring blades 26 is not limited to four, and may be one or two or three as long as the inside of the tank 19 can be efficiently stirred.
Alternatively, it may be 5 or more.

In order to dry the material to be dried using the vacuum drying apparatus of this embodiment, first, the lid 12, the drain valve 14, the leak valve 16 and the exhaust valve 42 are closed to make the tank 19 airtight. deep. Next, power is supplied to the heater 21 to heat the inner wall surface of the tank body 18 to 100 ° C. or higher, preferably 100 to 300 ° C. When heated sufficiently, the lid 12 is opened, the basket member 22 accommodating the material to be dried 50 is quickly set and fixed on the turntable 23, and the lid 12 is closed. Then, the drive motor 31 is driven to rotate the rotator 24, and the article to be dried 50 is centrifugally dehydrated. The water dewatered from the material to be dried 50 collides with the inner wall surface of the tank main body 18, is heated and evaporated, and becomes the heated steam to fill the inside of the tank 19. Then, the high-temperature heated steam further heats the material to be dried 50. Further, in the drying device of this embodiment, the inside of the tank 19 is stirred by the stirring blades 26, 26, ...
The steam to be heated or the heated air is evenly and finely spread over the material to be dried 50, and the dehydration is sufficiently performed. After this,
Open the exhaust valve 42, operate the vacuum pump 40,
The gas filled in the tank 19 is exhausted from the exhaust pipe 41 to bring the inside of the tank 19 to a high vacuum state to evaporate and dry the residual moisture adhering to the material to be dried 50. Finally, the exhaust valve 4
2 is closed, the leak valve 16 is opened, a leak gas is introduced into the tank 19, the lid 12 is opened, and the dried product is taken out. When the material to be dried is a metal that easily rusts, it is possible to prevent oxidation of the material to be dried and prevent rust by using an inert gas such as nitrogen gas, carbon dioxide gas, or argon gas as the leak gas. .

In the vacuum drying apparatus of this embodiment, at the time of centrifugal dehydration, an airflow is generated in the tank 19 by the stirring blades 26 as the rotor 24 rotates, and the tank 19 is stirred. Therefore, hot air is evenly applied to every corner of the material to be dried, the temperature of the material to be dried is increased, the dehydration efficiency is improved, the drying process is sufficiently performed, and the time of the drying step can be shortened. In particular, even if the material to be dried has a complicated shape or is biased by centrifugal dehydration, the material to be dried can be heated by the hot air blown by the stirring blades. Moreover, since the dehydration efficiency is high, it is not necessary to increase the rotation speed during centrifugal dehydration more than necessary, and damage to the dried object can be prevented.

In the above embodiment, the stirring blade 26 is provided on the turntable 23 of the rotating body 24.
6 may be provided on the basket member 22 other than the turntable 23. If the purpose is only to stir the inside of the tank, it may be possible to provide a stirring blade that can stir the inside of the tank separately from the rotor, but in that case, a new drive motor is provided. Etc. must be provided. However, according to the present invention, since the driving force of the centrifugal dehydration mechanism is used, a new driving source is not required, the structure does not become complicated, and the size can be reduced.
Furthermore, since the material to be dried can be stirred from the immediate vicinity thereof, the stirring efficiency is high.

Further, the turntable may be configured as shown in FIG. 3, for example. The turntable 36 shown in FIG. 3 is radially provided from the peripheral wall 37 and the rotating shaft 32 located in the central portion of the peripheral wall 37 toward the inner surface 38 of the peripheral wall 37, and the stirring blades 39 for connecting these are provided. Three
9 and so on, and unlike the turntable 23 shown in FIG. 2, does not have a bottom plate 29. Even with the turntable 36 having this configuration, the rotation causes the stirring blades 39 to stir the inside of the tank, which produces the same operation and effect as the above-described vacuum drying apparatus including the turntable 23. Further, the dehydration efficiency is improved, and since the bottom plate is not provided, the turntable can be reduced in weight and the operating cost can be reduced. In addition, since the water dehydrated from the material to be dried does not collect on the turntable, the dehydration efficiency is further improved.

(Test Example) A vacuum drying apparatus similar to that shown in FIG. 1 was prepared, and vacuum drying was performed according to the drying method described in the above-mentioned embodiment using a plurality of cylindrical bodies as the material to be dried. The dried state of the dried product was observed. The vacuum dryer has an inner diameter of 406.4 mm and a height of 415 m.
m, and other conditions were as follows. Material to be dried: φ1.6 × 3.2L, 4kg (absolute dryness: 25 ° C) Adhered water content: 0.2kg Set heating temperature: 200 ° C Rotational speed of rotor: 500rpm Centrifugal dehydration time: 1 minute Vacuum exhaust time: As a result of 2 minutes, all the materials to be dried had no moisture attached and were sufficiently dried. The temperature of the material to be dried after centrifugal dehydration had risen to about 80 ° C.

(Comparative Test Example) A similar vacuum dryer was used except that the turntable was not provided with a stirring blade.
The same test as the above test was conducted. As a result, the material to be dried was insufficiently dried and uneven. The temperature of the material to be dried after centrifugal dehydration was about 60 ° C., and it was found that the temperature of the material to be dried was smaller than that of the vacuum drying apparatus of the present embodiment having the stirring blade.

[0022]

EFFECT OF THE INVENTION The vacuum drying apparatus of the present invention contains a tank whose inside is airtight, an exhaust means for exhausting the inside of the tank, a heating means for heating the inside of the tank, and an object to be dried and the inside of the tank. In a vacuum drying device having a centrifugal dehydration mechanism having a rotating body rotatably installed in a rotary body, a stirring blade is provided on the rotating body, so that the centrifugal dryness causes the inside of the tank to come out from the immediate vicinity of the material to be dried. An airflow is generated in the tank to agitate the inside of the tank, the hot air is uniformly applied to the material to be dried, and the material to be dried is uniformly heated, so that the dehydration efficiency is increased and the drying efficiency is also increased. Therefore, with the vacuum drying apparatus of the present invention, even a device having a shape that is difficult to dry can be sufficiently dried in a short time.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a vacuum drying apparatus of the present invention.

FIG. 2 is a perspective view of a turntable according to this embodiment.

FIG. 3 is a perspective view of another embodiment of the turntable.

FIG. 4 is a side sectional view showing an example of a conventional vacuum drying device.

[Explanation of symbols]

 10 Tank 19 Tank 21 Heating Means 22 Basket Member 24 Rotating Body 25 Centrifugal Dewatering Mechanism 26 Stirring Blade 34 Basket Member 43 Exhaust Means 50 Dried Material

Claims (4)

[Claims] 1. A tank whose inside is airtight, an exhaust means for exhausting the inside of the tank, a heating means for heating the inside of the tank, and an object to be dried, which is rotatably installed in the tank. A vacuum drying apparatus having a centrifugal dehydration mechanism having a rotating body, wherein the rotating body is provided with stirring blades. 2. The vacuum drying device according to claim 1, wherein the rotating body is composed of a turntable and a basket member mounted on the turntable. 3. The vacuum drying apparatus according to claim 2, wherein the turntable has a bottom plate, and the stirring plate is provided on the bottom plate. 4. The vacuum drying device according to claim 2, wherein the turntable has a peripheral wall and a stirring blade radially provided from a central portion of the peripheral wall toward the peripheral wall. .