JPH07260346A - Drtying appartus by depressurizing - Google Patents

Abstract

PURPOSE:To shorten time required for drying, by a method wherein machined parts are dried without using a heater and without freezing, in a drying apparatus by depressurizing in which the machined parts are placed after washing thereof. CONSTITUTION:In a drying tank 1 by depressurizing, a shower device 5 which leads gas into the tank in the state of diffusion toward objects to be dried from a plurality of blowoff holes 7, and a gas supply pipe 6 for supplying the gas to the shower device 5 are provided. While the objects are being dried by depressurizing the inside of the tank 1, the gas is showered on the objects through the shower device 5 before the freezing of the objects. Pressure change in the tank 1 is repeated several times and the objects are dried.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum dryer for cleaning synthetic resins and metallic materials, especially machined parts.

[0002]

2. Description of the Related Art Synthetic resins and metal materials, especially machined parts, need to be cleaned of oil and cuttings before being sent to the next step. It was stored, put in a cleaning tank, and cleaned with a cleaning agent such as CFC or trichloroethane, but alternative cleaning agents have come to be used due to problems with air pollution. However, when an alternative cleaning liquid is used, the drying as the final step of cleaning is not as easy as with conventional CFCs and ethane.

That is, as a drying method, hot air drying in which a solvent is diffused with hot air after washing and vacuum drying in which a solvent is diffused in a vacuum are used, but the former requires a large amount of heat energy and is flammable. The vacuum drying of the latter is not suitable for machined parts with complicated shapes and many holes. It is used.

[0004]

However, in vacuum drying, when the cleaning liquid evaporates in a vacuum, heat of evaporation is taken from the material to be dried, so that the material to be dried is cooled and finally freezes. However, there is a problem that it is necessary to install a far-infrared heater or the like to prevent freezing due to radiant heat, and it takes a long time to dry.

An object of the present invention is to carry out vacuum drying without using a heater or the like for preventing freezing, and to dry without freezing, thereby shortening the time required for drying.

[0006]

Therefore, when the atmospheric pressure in the vacuum tank reaches a constant value, a gas such as air or an inert gas such as nitrogen diffuses toward the material to be dried in the tank during drying. A shower device for drawing in is provided, and the pressure in the drying tank is repeatedly changed by the gas from the shower device while the pressure in the drying tank is reduced and the drying is performed.

[0007]

[Operation] Therefore, due to the pressure change in the drying tank,
Before the material to be dried freezes, the atmospheric pressure is raised to prevent excessive heat dissipation due to boiling evaporation, so that it does not reach the freezing point, and the vapor in the tank is evaporated by using gas as a medium. Is effectively repeated, and quick drying is performed.

[0008]

EXAMPLE An example shown in the drawings will be described below. 1
Is a drying tank, 2 is a lid, and 3 is a pedestal, and holds a drying basket 4 containing an object to be dried. It is desirable to share this dry basket with the cleaning basket for cleaning. Reference numeral 5 denotes a shower device provided in an upper part of the drying tank 1, for example, on the lower surface of the lid body 2. The shower device 5 has a plurality of blowing holes 7 for downwardly opening gas such as air or nitrogen supplied from the gas supply pipe 6.
To the dry basket 4 in the drying tank in a diffused state. Reference numeral 8 is an exhaust pipe connected to a vacuum pump through a gas-liquid separator (not shown), 9 is packing, and 10 is a valve of a gas supply pipe, for example, a solenoid valve.

Reference numeral 11 denotes a support shaft of the pedestal 3, which is rotated by the actuator 12 or an appropriate angle, for example, 90 °.
It is designed to rotate back and forth at 180 °. Reference numeral 13 denotes a rinse liquid supply pipe for supplying a rinse liquid to the shower device 5,
Reference numeral 14 is a valve of the rinse liquid supply pipe, for example, a solenoid valve, and 15 is a liquid discharge port.

A cradle 3 in the drying tank 1 holds a dry basket 4 containing the machined parts that have been cleaned.
If the cleaning basket for cleaning is used as it is, the dry basket 4 may be transferred from the cleaning bath to the drying tank with the cleaning parts still in the cleaning basket. After closing the lid 2, dry basket 4
When there is a large amount of water attached to the material to be dried, the pedestal 3 is rotated at a high speed or 90 °
It is reciprocally rotated at 180 ° to drain the liquid adhering to the material to be dried. When the draining is completed, the gas in the drying tank is sucked out from the exhaust pipe 8 to reduce the pressure in the drying tank. At this time, both valves 10 and 14 are closed.

As shown in FIG. 3, when the liquid pressure in the drying tank 1 is lowered to cause the liquid to bump, and the pressure is reduced to an appropriate pressure, for example, minus 680 mm / Hg, the valve 10 is opened while continuing the exhaust from the exhaust pipe 8. When an appropriate amount of gas is instantaneously sent to the shower device 5 from the gas supply pipe 6 when opened, this gas is instantaneously drawn into the depressurized drying tank 1 and heads to the material to be dried in the drying basket 4 through the blowing hole 7. The diffused gas shower is showered.

This gas shower has a temperature higher than that of the object to be dried which is being cooled and has a function of warming the object to be dried, and raises the atmospheric pressure in the drying tank 1, and the atmospheric pressure is minus 40.
When the pressure rises to about 0 mm / Hg, the supply of gas is stopped and the pressure is reduced, and when the material to be dried is not dried, for example, minus 750 mm / Hg, the gas is showered again when the pressure is reduced and dried.

By repeating this several times, the liquid of the material to be dried is bumped by the reduced pressure, and before it is frozen by the cooling action by the heat of evaporation, it is exposed to a gas shower to raise the atmospheric pressure in the tank to dry it. Allow the material to dry while preventing it from overcooling. For this reason, evaporation is smoothly performed without causing freezing, and the drying time is rather shortened.

In this embodiment, the pedestal 3 is provided with the support shaft 11, and the support shaft 11 is connected to the actuator 12 or the crank device so as to be rapidly rotated or reciprocally rotated. Therefore, before storing the material to be dried after cleaning in the drying tank 1 and performing drying, the valve 14 is opened and the new rinse liquid is supplied from the rinse liquid supply pipe 13 to the shower device 5 without reducing the pressure or in the reduced pressure state. And the rinse liquid is sprayed from the blow-out hole 7 toward the object to be dried to perform rinsing, and the support shaft 11 is rotated at high speed or reciprocally rotated by the actuator 12 or the crank device to drain water, and then the above-mentioned drying is performed. be able to. The liquid used for rinsing is discharged by opening the liquid discharge port 15 at the bottom of the drying tank.

In the embodiment shown in the drawings, the shower device 5 is provided on the lower surface of the lid body 2 integrally with the lid body, but it may be provided separately depending on the structure of the lid body, for example, in the periphery of the drying tank 1. Etc. can be provided at an appropriate place.

According to the present invention, the effect can be further enhanced by preheating the gas supplied to the shower device and supplying the gas having a high temperature. Improves the effect of drying by improving the bond with. Further, it can also be applied to a drying device provided with a means for warming the material to be dried during drying, by reducing the temperature decrease of the material to be dried in addition to the effect of the present invention,
The drying effect can be further enhanced.

[0017]

As described above, according to the present invention, the shower device is provided in the upper portion of the drying tank, and the gas is instantaneously and repeatedly fed during the drying by the reduced pressure so that the gas sucked in the tank is sprayed on the material to be dried. Since the gas shower is performed as described above, the adsorption action of the vapor and the gas generated by the bumping in the depressurized tank is accelerated, and the moisture is efficiently discharged.

Although the heat of evaporation is removed from the material to be dried by the bumping drying and the material to be dried is cooled, the gas shower is showered before the material to be dried freezes to bring the material to be dried into contact with the gas and the atmospheric pressure. Can be prevented from freezing and damage due to freezing, evaporative drying is continued even if heat energy to heat the material to be dried with a heater is not required, evaporation is performed due to pressure change, and pressure reduction in the tank is excessive. Therefore, the drying time can be shortened by a simple operation.

By heating or drying the gas supplied to the shower device in advance, the drying can be performed more effectively. Further, the drying effect can be further enhanced by applying it to a drying device that warms the material to be dried during drying.

By mounting the shower device on the lower surface of the lid provided on the upper part of the drying tank, the structure becomes simpler than the case where the shower device is separately provided inside the tank, and the shower device can be arranged at the center of the tank. In addition, it is possible to perform rinsing by a shower device before drying, and immediately after cleaning, transfer to a drying tank for rinsing and drying, which has the effect of smoothing the flow of the production process and increasing production efficiency.

Further, by supporting the pedestal for holding the dry basket so as to be rotatable or rotatable, the dried product can be drained in the tank before drying, and the drying time can be shortened.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a drying device according to the present invention.

FIG. 2 is a bottom view of the shower device taken along the line AA of FIG.

FIG. 4 is a characteristic diagram showing an example of pressure change in the drying tank according to the present invention.

[Explanation of symbols]

 1 Drying Tank 2 Lid 3 Cradle 4 Drying Basket 5 Shower Device 6 Gas Supply Pipe 7 Blowout Hole 8 Exhaust Pipe 9 Packing 10 Valve 11 Support Shaft 12 Actuator 13 Cleaning Liquid Supply Pipe 14 Valve 15 Liquid Discharge Port

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[Procedure amendment]

[Submission date] July 6, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a drying device according to the present invention.

FIG. 2 is a bottom view of the shower device taken along the line AA of FIG.

FIG. 3 is a characteristic diagram showing an example of a pressure change in the drying tank according to the present invention.

[Explanation of symbols] 1 dry tank 2 lid 3 cradle 4 dry basket 5 shower device 6 gas supply pipe 7 blowout hole 8 exhaust pipe 9 packing 10 valve 11 support shaft 12 actuator 13 cleaning liquid supply pipe 14 valve 15 liquid discharge port

Claims (4)

[Claims] 1. A drying tank containing a material to be dried and a shower device for drawing gas in a diffusive state into the drying tank, and the drying device is drawn in from the shower device while the pressure in the drying tank is reduced and drying is performed. The reduced pressure drying device is characterized in that the pressure change in the drying tank is repeated by the generated gas. 2. The reduced pressure drying apparatus according to claim 1, wherein the gas is heated. 3. The reduced pressure drying apparatus according to claim 1, wherein the gas is dried. 4. The reduced pressure drying apparatus according to claim 1, wherein the material to be dried is heated in advance or during drying.