JPH03220722A - Method and device for drying work - Google Patents

Abstract

PURPOSE:To make it possible to dry work definitely and promptly irrespective its shape by drying the work, using both hot pure water drying and vacuum drying. CONSTITUTION:An attempt is made to install a hot pure water tank 10 designed to fill hot pure water 11 used to submerge wet work 5 and a vacuum tank 30 for vacuum drying, and a transfer mechanism 3 which transfers the work 4 polled up from the hot pure water tank 10 between the hot pure water tank 10 and the vacuum tank 30. The wet work 4 is submerged to the hot pure water 11 and heated and then polled up from the water. After the hot pure water is dried, the work is housed and subjected to vacuum drying while its quantity of heat is maintained. This construction makes it possible to dry the work definitely and promptly irrespective of its shape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drying method and apparatus for drying a workpiece that is wet due to cleaning or the like.

[Prior Art] Conventionally, as disclosed in Japanese Unexamined Patent Publication No. 64-53549, a workpiece wet from cleaning or the like is immersed in warm pure water at a predetermined temperature, heated, and then slowly pulled up. A hot pure water drying method in which the workpiece is dried using its own heat is known. Such a hot pure water drying method does not use an organic solvent, so there is no problem of environmental pollution, and the equipment and management are simple, so it is attracting attention as the most suitable method for drying various types of workpieces.

However, in the hot pure water drying method described above, if water accumulates in a part of the work when the work is pulled out of the warm pure water, the drying of that part will be delayed and it will take a long time to finish, and the drying will not be completed partially. Due to the drying delay, some stains may remain, which is a problem when drying workpieces that have a shape where water tends to accumulate, such as a workpiece with a wide upward facing surface, a blind hole, four parts, etc. In particular, when a workpiece is pulled out of hot pure water, it gradually cools down as the heat of vaporization is removed by drying, and as it cools, it becomes difficult to dry. If you don't evaporate it as quickly as possible, there is a high chance that it will remain in that area.

Is there a way to dry the workpiece by blowing hot air onto it? With this hot air drying method, the blowing of hot air may cause uneven drying depending on the direction, or water droplets may be blown away by the hot air and may have already dried. As it evaporates and dries as it moves over the exposed surface, the formation of stains is unavoidable, making precise drying impossible. Moreover, depending on the shape of the workpiece, there is also the disadvantage that the part on which water droplets are attached becomes a blind spot to the warm air, and it takes a long time to dry.

Furthermore, vacuum drying methods are also known, and in such vacuum drying, the thermal energy necessary to evaporate water droplets or accumulated water on the workpiece must be obtained from the workpiece itself, so it is necessary to lower the temperature by cleaning etc. If the workpiece is vacuum-dried as it is, there are problems such as the temperature of the workpiece further dropping and freezing, and drying taking a long time. It is possible to supplementally heat the workpiece in a vacuum drying device, but this requires a large-scale heating device, and it is difficult to efficiently and evenly transfer heat from the heating device to the workpiece. Therefore, it takes a long time to heat to a specified temperature. For example, when performing a series of processes from washing to drying, the heat required within the limited time (about 5 minutes) that can be spent on the drying process. It is almost impossible to give enough energy to the work and finish it dry in a short time.

Problems to be Solved by the Invention j An object of the present invention is to provide a drying method and apparatus that can reliably and quickly dry a workpiece regardless of its shape.

[Means for Solving the Problems] In order to solve the above problems, the drying method of the present invention immerses a wet workpiece in warm pure water, heats it, takes it out, and then dries it with warm pure water. It is characterized in that it is housed in a vacuum chamber and vacuum-dried in the vacuum chamber.

Furthermore, the apparatus of the present invention includes a warm pure water tank for filling warm pure water into which a wet workpiece is immersed, and a vacuum tank for vacuum drying the workpiece. This system is characterized by the provision of a transport mechanism for transporting the workpiece pulled up from the +11ff water tank to the vacuum layer.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The drying apparatus shown in Fig. 1 includes a warm pure water drying section 1 that immerses and dries the wet workpiece 4 sent from a cleaning mechanism in the previous stage in warm pure water, and a vacuum drying section 1 that dries the workpiece 4 that has been dried with warm pure water under vacuum. 2 and a transport mechanism 3 for transporting the workpiece 4 from the hot pure water drying part 1 to the vacuum drying part 2.

The warm pure water drying section] is a warm pure water tank 1 for filling warm pure water 11 from which impurities have been removed and heated to a predetermined temperature.
The hot pure water tank 10 is equipped with a pure water source 12 at its bottom via a heater 13 that uses electric heat, steam, etc. as a heat source.
The pure water from the pure water fi12 is heated to a predetermined temperature by the heater I3 and supplied from the bottom. Note that the heater 13 may be provided at the inner bottom of the warm pure water tank 10 to heat the pure water within the tank 10. A bubble remover 14 is installed inside the warm pure water tank 10, and the bubble remover 14 is used to prevent air bubbles generated when the warm pure water is supplied or when the pure water is heated by a heater installed in the tank. It is preferable to collect the hot water and discharge it to the outside through the discharge pipe 14a. This can prevent air bubbles from undulating the surface of the warm pure water 11 and adversely affecting the drying of the warm pure water.

A recovery groove 15 is formed around the warm pure water tank IO to recover the warm pure water overflowing from the warm pure water tank 10, and the warm pure water recovered by the recovery groove 15 is discharged to the outside through a recovery pipe 16. There is.

In this case, a heat-resistant filter 17 is provided in the recovery pipe 16, and after the impurities in the warm pure water are removed by the filter 17, the warm pure water is supplied to the heater 13 or the pure water source 12 and reused cyclically. Furthermore, a drying chamber 20 surrounded by a partition wall 21 is formed above the hot pure water tank 10. The drying chamber 20 is for accelerating the drying of the work 4 pulled up from the warm pure water 11, and is connected to an exhaust fan 25 via a mist catch 24 by an exhaust pipe 23 connected to an exhaust port 22. By sucking and discharging the water vapor that evaporates from the water surface and the surface of the workpiece 4 at step 25, the water vapor is prevented from coming into contact with the workpiece 4 and wetting the workpiece 4. At this time, the water vapor is g In order to achieve more effective contact prevention by horizontal suction, a plurality of partition plates 26 that generate horizontal airflow are provided inside the drying chamber 20, the angle of which can be adjusted freely. The pure water collected by the stock catch 24 is discharged through the drain pipe 27 by the collection pipe 16.

On the other hand, the vacuum drying section 2 includes a vacuum chamber which is opened and closed by a lid 31 and is equipped with a mounting table 32 for placing the workpiece 4 therein and an in-tank heater 33 for assisting in drying the workpiece 4. There are 30. The vacuum chamber 30 is connected to a vacuum pump 38 through a suction pipe 35 through a valve 36 and a cold trap 37, and is connected through a valve 42 to an air guide pipe 41 for introducing outside air equipped with a heater 39 and an air filter 40. The suction pipe 35 and the air guide pipe 41 are connected to each other by a connecting pipe 43 via a valve 44 . Further, a drain pipe 45 for discharging water flowing down from the workpiece 4 is connected to the bottom of the vacuum chamber 30, and the drain pipe 45 is connected to the cold trap 37 or a connecting pipe 46. The cold trap 37
In order to separate the water vapor contained in the air and prevent it from being sucked into the vacuum pump 38 along with the air, the oil waste used for lubricating the vacuum pump 38 or the suction pipe 35 is separated. It may be installed as necessary to prevent the phenomenon of contaminating the work 4 by flowing back into the vacuum chamber 3o through the valve.

The in-tank heater 33 can be constructed from an appropriate heating source such as an infrared lamp or a panel heater.

Furthermore, the transport mechanism 3 that transports the work 4
The transport arm 51 is arranged to be movable along a guide 52, and is moved by a driving means such as a ball screw, a timing belt, or a cylinder. The transport arm 51 includes a hook 53 for hanging the basket 50, a driving means 54 consisting of a ball screw 55 and a motor 56 for raising and lowering the hook 53, and a pair of driving means 54 for guiding the raising and lowering of the hook 53. It is composed of a guide 57. Incidentally, the driving means 54 for the hook 53 may be constituted by a timing belt, a cylinder, or the like.

The drying device having the above configuration is disposed, for example, after the cleaning mechanism, and dries the workpiece 4 that is sent in a wet state due to cleaning, and operates as follows.

That is, when the work 4 placed in the basket 50 is suspended by the transport arm 51 and carried to the upper part of the warm pure water tank IO in the warm pure water drying section 1, the hook 53 descends and the work 4 is suspended in the warm pure water 11. immersed in.

At this time, in the warm pure water drying section 1, warm pure water 11 heated to a predetermined temperature is continuously supplied in a predetermined amount into the warm pure water tank 10, and the overflowing warm pure water is removed from the recovery groove 1.
The air in the drying chamber 20 is sucked in by the exhaust fan 25, and the water vapor evaporated from the water surface is discharged horizontally along with this air flow.

When the work 4 is immersed in warm pure water 11 for a certain period of time and heated, the hook 53 slowly rises, and the work 4 is pulled out of the warm pure water at a slow speed that does not disturb the liquid level. As a result, the workpiece 4 is sequentially dried by its own heat starting from the portion drawn out from the warm pure water, and drying with warm pure water is performed. In addition, in the drying chamber 20, the water vapor evaporated from the water surface is discharged in the X horizontal direction by the exhaust fan 25, so that it does not come into contact with the workpiece 4. It does not get wet, so there is no uneven drying or formation of wrinkles due to rewetting.

1 The appropriate temperature of the above warm pure water 11 depends on the type of workpiece 4 and the filter 1.
7 Will it differ depending on the heat resistance of other incidental equipment?
It is desirable to keep the temperature as high as possible within a range that does not cause thermal denaturation; for example, when the workpiece 4 is made of glass, aluminum, etc., about 80°C is suitable. Of course, the temperature may be lower than this. In addition, the immersion time of the workpiece 4 in the warm pure water 11 and the pulling speed when lifting it from the warm pure water 11 may vary depending on the temperature of the warm pure water 11 and the type of the workpiece 4. For example, the temperature of the warm pure water is 80°C. In this case, if the workpiece 4 is a flat glass plate used for instrument covers, the immersion time is approximately 30 to 60 seconds, and the pulling speed is 8 to 12+n+n.
/sec, and in the case of Work 4 or an aluminum tie-cast product, the immersion time is approximately 30~30 seconds.
60 seconds, and the pulling speed may be about 5 to 8 mm/sec.

In addition, after the workpiece 4 is completely pulled up from the warm pure water, the workpiece 4 may be raised at a speed faster than the above-mentioned lifting speed in order to speed up the subsequent work.

When the hot pure water drying process is completed, the workpiece 4 is immediately sent to the vacuum drying section 2 by the transfer arm 51 before the workpiece 4 has cooled down much. When the transfer arm 51 moves to the upper part of the vacuum chamber 30 which has been opened by the lid 31, the workpiece 4 is placed on the mounting table 32 inside the vacuum chamber 30 while being placed in the basket 50 due to the lowering of the hook 53. , the basket 50 is removed from the hook 53. Then, the hook 53 that has released the basket 50 rises, and the lid 31 is closed. At this time, if water droplets adhering to the wide upward surface, blind hole, recess, etc. of the workpiece 4 flow down and accumulate at the bottom of the vacuum chamber 30, they are discharged through the drain pipe 45.

Subsequently, the Harz 42 of the air guide pipe 41 is closed, and the Harz 35 of the suction pipe 35 is opened, and the air in the vacuum chamber 30 is exhausted by the vacuum pump 38, and the vacuum chamber 30 reaches a predetermined degree of vacuum. By the way, the HARTZ 42 is opened to an appropriate amount, and the vacuum chamber 30 is maintained at a predetermined degree of vacuum (for example, about 4.5 torr) while the Calorie air heated by the heater 39 is flowing in an appropriate amount through the four air guide pipes. In this state, the workpiece 4 is vacuum dried.

At this time, the workpiece 4 is heated by the in-tank heater 33 as necessary.
is heated auxiliary.

By the vacuum drying, the moisture that has adhered to the upward facing surface, blind hole, four parts, etc. of the workpiece 4 and could not be completely removed by the hot pure water drying is immediately evaporated and removed, and the workpiece 4 is quickly dried. Therefore, stains do not occur due to water droplets remaining for a long time after drying with hot pure water. Moreover, unlike in the case of hot air drying, water droplets are not blown away by the hot air and moved on the surface of the dried workpiece 4, so no stains are caused by this. In addition, supply of heated air and tank heater 3
3 prevents the temperature of the workpiece 4 from decreasing due to vacuum drying, thereby preventing the workpiece 4 from freezing and improving drying efficiency. However, if the workpiece 4 is dried in warm pure water and then vacuum-dried while retaining sufficient heat, it is not necessarily necessary to supply heated air and heat the tank heater 33. Either one or both can be omitted.

The time required for the vacuum drying may depend on the type of workpiece 4, but usually about 30 to 50 seconds is sufficient.

When the vacuum drying is thus completed, the inside of the vacuum chamber 30 is returned to atmospheric pressure, the lid 31 is opened, and the work 4 is taken out together with the basket 50 by the transfer arm 51 and sent to the next process.

[Effect of the Invention J As described above, according to the present invention, by drying a workpiece using a combination of hot pure water drying and vacuum drying, it is possible to dry not only a workpiece with a simple shape that drains easily but also has no water droplets attached. Even if the workpiece has a special shape where water can easily collect, such as a workpiece with a wide upward facing surface, a blind hole, a recess, etc., the water droplets and water can be reliably and quickly evaporated to prevent uneven drying and drying. It is possible to dry it without causing stains due to delays, etc.

In addition, after drying the workpiece with warm pure water, the workpiece is vacuum-dried while still retaining sufficient heat, so there is no need to preheat the workpiece during vacuum drying, and therefore, the workpiece can be directly vacuum-dried. There is an advantage that large-scale equipment, time, etc. required for preheating as in the case of drying can be reduced or omitted.

[Brief explanation of drawings]

FIG. 1 shows the configuration of an embodiment of a drying apparatus according to the present invention. 3. Transfer mechanism, 4. Workpiece, 10. Warm pure water tank, 11. Warm pure water 30. Vacuum tank. 6

Claims (1)

[Claims] 1. After immersing a wet workpiece in warm pure water, heating it, and then taking it out to dry it with warm pure water, it is placed in a vacuum chamber while retaining heat, and vacuum dried in the vacuum chamber. A workpiece drying method characterized by: 2. Equipped with a warm pure water tank for filling warm pure water for immersing wet workpieces and a vacuum tank for vacuum drying the workpieces, and between these warm pure water tanks and the vacuum tank, the workpieces lifted from the warm water tank are placed. A workpiece drying device characterized by being provided with a transport mechanism for transporting the material to a vacuum layer.