JPH06213562A - Vacuum drier - Google Patents

Abstract

PURPOSE:To reduce a consumption of inert gas by providing an inert gas circulation means, when an inert gas is fed into a vacuum drier chamber to dry a work under vacuum, and providing a gas heater and a gas cooler in a gas introducing means and a gas suction pipe respectively. CONSTITUTION:When a work such as parts of automobile which has been washed with solvent is dried, at first a basket B storing therein a work A is put into a vacuum drier chamber 1 and a cover 2 is closed, following which a vacuum pump 8 is actuated, while a rotary table 4 is being rotated, to exhaust the interior 1a of a room to a set vacuum. And next, a gas circulation means 9 is actuated so that when a piston 9b of the means 9 advances, an inert gas is heated by a gas heater 13 to feed it into the interior 1a through a gas introducing pipe 11 and thereafter the piston 9b is retracted so that the inert gas containing solvent etc., is drawn out through a gas suction pipe 12 to cool it at a gas cooler 14, thereby separating the inert gas and solvent, whereby the inert gas only is returned to the means 9. By repeating the aforementioned step, drying is effected.

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 vacuum-drying workpieces such as automobile parts and light electric equipment parts washed with a solvent or the like.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a vacuum drying device of this type has a gas introducing pipe 21 and a vacuum suction pipe 22 connected to a vacuum drying chamber 20, and an inert gas is supplied to the end of the gas introducing pipe 21. A source 23 is provided, and a gas heater 24 is provided in the middle of the gas introduction pipe 21.
On the other hand, a vacuum pump 25 is provided at the end of the vacuum suction tube 22.

Then, a basket B containing a work A such as automobile parts and light electric equipment parts washed with a solvent is put in a vacuum drying chamber 20, and a valve 26 provided in a vacuum suction pipe 22 is opened to open a vacuum pump. 25 to drive the vacuum drying chamber 2
0 is evacuated, then the valve 26 is closed and the valve 27 provided in the gas introduction pipe 21 is opened to heat the inert gas introduced from the inert gas supply source 23 by the gas heater 24, The heated inert gas is supplied into the vacuum drying chamber 20, and the above operation is repeated several times to several tens of times to dry the work A.

[0004]

However, in the above vacuum drying apparatus, the inert gas is supplied to the vacuum drying chamber 20 and the vacuum pump 25 exhausts the inert gas from the vacuum drying chamber 20 to perform this operation. Since the process is repeated many times, a large amount of inert gas is exhausted to the outside of the vacuum drying chamber 20, which causes a problem of high gas running cost.

Further, the inert gas exhausted contains a solvent,
Since the liquid such as oil is contained, there is a problem that the vacuum pump 25 is deteriorated and the life is shortened. The present invention has been devised to solve the above problems, and an object of the present invention is to provide a vacuum drying device that can reduce gas running costs and improve the durability of a vacuum pump.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a vacuum drying apparatus for vacuum-drying the inside of a vacuum drying chamber with a vacuum pump and supplying an inert gas to the vacuumed chamber to perform vacuum drying. A gas circulating means for circulating an inert gas isolated from the chamber is connected, and the gas circulating means and the vacuum drying chamber are connected by a gas introduction pipe and a gas suction pipe, and an inert gas is provided in the middle of the gas introduction pipe. Is provided, and a gas cooler for separating into an inert gas and a liquid is provided in the middle of the gas suction pipe.

[0007]

According to the above construction, after the vacuum drying chamber is evacuated by the vacuum pump,
The inert gas heated by the gas heater is introduced into the room and contributes to the drying. Next, the inert gas in the room used for drying is separated into the inert gas and the liquid by the gas cooler, and again heated and regenerated by the gas heater by the gas circulation means to supply the inert gas to the room. It This operation is repeated several times to dry the work.

Therefore, the inert gas is not wastefully exhausted outside the vacuum drying chamber, and the gas running cost is reduced. Further, since the vacuum pump is used only to make the inside of the vacuum drying chamber into a vacuum only at the beginning of vacuum drying, deterioration is less and durability is improved.

[0009]

The present invention will be described in detail below with reference to the drawings. FIG. 1 shows an embodiment of the vacuum drying apparatus of the present invention.

In the figure, a vacuum drying chamber 1 is composed of a container having heat resistance and pressure resistance, and is provided with an opening / closing lid 2 which is closed at an upper opening. The opening / closing lid 2 is hinged by an opening / closing lever 3, and an end of the opening / closing lever 3 is provided with a lid opening / closing cylinder 4 provided outside the vacuum drying chamber 1.
Is provided so that the opening / closing lid 2 can be opened and closed.

On the chamber 1a side of the bottom 5 of the vacuum drying chamber 1,
A rotary table 4 is provided to support a work A, such as automobile parts and light electric equipment parts, which have been washed with a solvent or the like, while being housed in a basket B. A rotation drive unit 6 such as a drive motor is provided outside the bottom portion 5, and the rotation drive unit 6 can rotate the rotary table 4.

A vacuum suction pipe 7 is connected to the vacuum drying chamber 1, and a vacuum pump 8 for evacuating the chamber 1a is provided at its end. A valve B1 that opens and closes is provided in the middle of the vacuum suction pipe 7.

A gas circulating means 9 composed of a breathing cylinder is provided separately from the vacuum drying chamber 1. The gas circulating means 9 has a cylinder 9a having substantially the same capacity as the vacuum drying chamber 1, and a piston 9b slides in the cylinder 9a.

The gas circulating means 9 is provided with an actuator 10 composed of, for example, an air cylinder.
A control valve 10a for controlling the actuator 10 is connected to the actuator 10.

Between the vacuum drying chamber 1 and the gas circulating means 9, the gas introducing pipe 11 for supplying the inert gas from the gas circulating means 9 to the vacuum drying chamber 1 and the used inert gas from the vacuum drying chamber 1 are introduced. It is connected to the gas circulation means 9 by a gas suction pipe 12 that sucks gas.

A vacuum drying chamber 1 is provided in the middle of the gas introducing pipe 11.
A gas heater 13 provided with a heater or a steam pipe 13a for heating an inert gas supplied to
On the other hand, in the middle of the gas suction pipe 12, there is provided a gas cooler 14 for separating a liquid such as a solvent or oil contained in the used inert gas and a pure inert gas.

The gas cooler 14 has a container 14a having an inverted pyramid shape and a refrigerant pipe 14b through which a refrigerant passes.
Drain valves B2 and B3 are provided at the bottom of 4a. Below the container 14a, the stored liquid is recovered by alternately opening the two valves B2 and B3 so that the liquid such as solvent and oil is recovered in the recovery container 15 provided therebelow. ing.

Valves B4 and B5 and valves B6 and B7 for opening and closing, respectively, are provided on the sides of the gas introducing pipe 11 and the gas suction pipe 12 close to the gas circulating means 9 and the vacuum drying chamber 1.
Is provided so that the supply and suction of the inert gas can be controlled.

The gas recirculation means 9 includes a gas supply pipe 1
6 is connected and an inert gas supply source 17 is provided at its end. By opening the valve B8 provided in the gas supply pipe 16, the inert gas can be supplied to the gas circulating means 9 side when necessary.

The vacuum drying chamber 1 is connected with an air introducing pipe 18 provided with a valve B9 for keeping the chamber 1a at a normal pressure when the opening / closing lid 2 is opened, and displays the degree of vacuum. A gauge 19 is provided.

The vacuum drying apparatus of the present invention has such a structure, and the procedure and operation of the drying process using the apparatus will be described below. First, the lid opening / closing cylinder 4 is driven to open the opening / closing lid 2 on the upper portion of the vacuum drying chamber 1, and the chamber 1a is opened.
The basket B containing the work A to be dried is placed on the rotary table 4, and the opening / closing lid 2 is closed.

Thereafter, the vacuum drying operation is started, but the rotary table 4 on which the basket B is placed is rotated at a predetermined rotation speed. The rotary table 4 may be rotated several times per minute.

The valve B1 is opened and the vacuum pump 8 is driven to bring the chamber 2 to a predetermined degree of vacuum, and then the valve B1 is closed. Next, the valves B4 and B5 provided in the gas introduction pipe 11 are opened, the actuator 10 is driven, and the gas circulation means 9 composed of a breathing cylinder is operated. Then, the piston 9b of the breathing cylinder is operated to move forward, and the inert gas is heated by the gas heater 13 provided in the gas introduction pipe 11 (for example, around 100 degrees C) to vacuum the heated inert gas. It is supplied to the room 1a of the drying room 1.

Then, the valves B4 and B5 are closed,
The valves B6 and B7 are opened to retreat the piston 9b of the breathing cylinder, and the inert gas containing the solvent and the like in the room 1a is sucked and cooled by the gas cooler 14 provided in the gas suction pipe 12. , A pure inert gas and a liquid such as a solvent or oil are separated, and only the pure inert gas is sucked into the gas circulating means 9 side including a breathing cylinder.

The separated liquid is stored at the bottom of the container 14a of the gas cooler 14, and the valves B2 and B3 provided at the bottom are alternately opened to change the atmospheric pressure in the container 14a. Instead, it can be collected in the collection container 15.

Then, a vacuum drying chamber 1 using a breathing cylinder
The above-described operations of supplying an inert gas to the vacuum drying chamber 1 and sucking the inert gas from the vacuum drying chamber 1 are repeated several times to several tens of times to perform a drying process.

The gauge 18 provided in the vacuum drying chamber 1
When the inert gas in the gas circulation system becomes insufficient, the valve B8 provided in the gas supply pipe 16
Is opened to supply the inert gas from the inert gas supply source 17 into the gas circulation system passage.

By this operation, the work A such as automobile parts and light electric equipment parts washed with the solvent is almost continuously supplied by the inert gas, whereby the drying is carried out rapidly and the heated high-purity inert gas is used. Is continuously supplied, so that it is dried with high precision.

Further, according to the vacuum dryer of the embodiment, the inert gas is circulated by the gas circulating means 9 and separated into the inert gas and the liquid by the gas cooler 14 provided in the middle of the gas suction pipe 12. The gas is heated by a gas heater 13 provided in the middle of the gas introduction pipe 11 and supplied again to the chamber 1 a of the vacuum drying chamber 1. That is, the once used inert gas is regenerated and repeatedly used to contribute to the drying.

Therefore, the inert gas is wastefully used as the vacuum drying chamber 1.
The gas running cost is reduced because it is not exhausted to the outside.
Further, since the vacuum pump 8 is used only to make the chamber 1a of the vacuum drying chamber 1 a vacuum only at the beginning of vacuum drying,
It is used less frequently, has less chance of coming into contact with solvent, has less deterioration, and has improved durability.

FIG. 2 shows another embodiment of the vacuum drying apparatus of the present invention. In this example, instead of the breathing cylinder of the above-described embodiment, the gas circulating means 9 is a circulation pump. Other than that, the gas supply pipe 16 provided with the inert gas supply source 17 is simply connected to the vacuum drying chamber 1 side,
This is almost the same as the above-mentioned embodiment.

In this case, the valves B4 and B5 provided in the gas introduction pipe 11 and the valves B6 and 6 provided in the gas suction pipe 12
Since B7 is opened and the inert gas can be continuously circulated by the circulation pump, the operation can be performed more efficiently.

[0033]

According to the present invention described above, the gas running cost can be reduced, the durability of the vacuum pump can be improved, and the work can be dried quickly and highly accurately. Is demonstrated.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of another embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional vacuum drying device.

[Explanation of reference numerals] A work B basket 1 vacuum drying chamber 1a chamber 7 vacuum suction pipe 8 vacuum pump 9 gas circulation means 11 gas introduction pipe 12 gas suction pipe 13 gas heater 14 gas cooler 17 inert gas supply source

Claims (1)

[Claims] 1. A vacuum drying apparatus for evacuating the inside of a vacuum drying chamber by a vacuum pump and supplying an inert gas to the vacuumed chamber to perform vacuum drying, wherein the inert gas is isolated from the vacuum drying chamber. A gas circulation means for circulating the gas is connected, the gas circulation means and the vacuum drying chamber are connected by a gas introduction pipe and a gas suction pipe, and a gas heater for heating an inert gas is provided in the middle of the gas introduction pipe. A vacuum dryer, characterized in that a gas cooler for separating into an inert gas and a liquid is provided in the middle of the gas suction pipe.