JP3106169B2 - Method and apparatus for cleaning workpieces such as metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cleaning a workpiece such as a metal which is effective for washing off high-viscosity and low-vapor-pressure oil such as hot-bath quenching oil. And safe and pollution-free.

[0002]

2. Description of the Related Art Conventionally, as a method of cleaning a workpiece such as a metal to which oil has adhered, a method of pre-cleaning using water or steam, or water or steam containing a surfactant or an alkali (Japanese Patent Laid-Open No. 3-140485). However, there have been problems such as low cleaning ability, stains on the object to be cleaned, and an increase in cost for waste liquid treatment.

[0003] Low boiling solvents (flash point 35 degrees Celsius)
Although a pre-cleaning method (Japanese Patent Publication No. 3-49633, etc.) is also used, safety measures against explosion are costly, and there is still a problem in reliability of the safety measures.

[0004] In addition, a cleaning method using a chlorine-based solvent or a fluorine-based solvent having a high cleaning ability has been proposed. However, there is a risk of causing pollution such as environmental pollution, and the use thereof is currently being restricted. is there.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and can be carried out in an open-to-atmosphere state, is excellent in cleaning effect, is a safe and non-polluting method for short-time cleaning of a work such as a metal and the like. It is intended to provide a device.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the invention of the method of the present invention comprises cleaning a workpiece such as a metal by immersing the workpiece in a cleaning liquid comprising a high-boiling aromatic hydrocarbon compound or spraying the cleaning liquid. Then, the cleaning liquid is evaporated and removed in a decompression chamber, and the invention of the apparatus further includes a pre-cleaning tank having a cleaning liquid comprising a high-boiling aromatic hydrocarbon compound, and a heating element connected to the pre-cleaning tank and having a heating element. A vacuum cleaning chamber for evaporating the cleaning liquid adhering to the workpiece; a cleaning liquid purifying and circulating device connected to the pre-cleaning tank; and a cleaning liquid collecting device provided from the reduced pressure cleaning chamber. The cleaning liquid is connected to an apparatus, and the collected cleaning liquid is circulated to the pre-cleaning tank via the cleaning liquid purifying and circulating apparatus.

[0007]

The front door 5 of the pre-cleaning tank 2 is opened, and a workpiece 4 such as a metal to which oil has adhered is supplied onto an elevator (not shown) in the pre-cleaning tank 2. Next, the elevator is lowered, and the workpiece 4 such as a metal is immersed in a cleaning liquid 6 comprising a high-boiling aromatic hydrocarbon compound.

The immersion is carried out for a period of time sufficient to completely remove the oil adhering to the workpiece 4 such as a metal, and then lifted up by an elevator. Further, the intermediate door 8 is opened to depressurize the workpiece 4 such as a metal. It is supplied to the cleaning room 3.

Next, the intermediate door 8 is closed and the decompression cleaning chamber 3 is closed.
Is made airtight, and the inside of the reduced-pressure cleaning chamber 3 is depressurized by the vacuum pump 24, and is simultaneously heated by the heating element 9. As a result, the cleaning liquid 6 is evaporated and removed from the workpiece 4 such as a metal.

Thereafter, the cleaning liquid 6 evaporated into the reduced-pressure cleaning chamber 3 is supplied to the water-cooled condenser 23 together with the gas, and the cleaning liquid 6 is condensed and recovered by the water-cooled condenser 23, and the separated gas is discharged to the outside by the vacuum pump 24. Is discharged.

On the other hand, in the cleaning liquid 6 in the pre-cleaning tank 2, oil which has been washed off from the workpiece 4 such as a metal is mixed, and in order to prevent a decrease in the cleaning performance, the mixing ratio of the oil is detected. To open the valve 16 in the pipe 12
Can be driven.

As a result, the cleaning liquid 6 containing oil is supplied to the heater 13 to be heated to a predetermined temperature, and further supplied to the fractionator 15 evacuated by the vacuum pump 19 to evaporate the cleaning liquid 6 under vacuum. The oil is stored in the lower part of the fractionator 15. Simultaneously, the vapor-like cleaning liquid 6 evacuated by the vacuum pump 19 is condensed and recovered by the water-cooled condenser 16, and the separated gas is discharged to the outside by the vacuum pump 19.

Thereafter, the cleaning liquid 6 recovered by driving the pressure feed pump 17 and operating the valve is circulated to the pre-cleaning tank 2 through the pipe 18. Further, in the apparatus of the present invention, the cleaning liquid 6 collected in the water-cooled condenser 23 on the side of the reduced-pressure cleaning chamber 3 is also circulated to the pre-cleaning tank 2 by the pressure feed pump 17 through a pipe 25 provided from the water-cooled condenser 23. Used for washing. The oil fraction fractionated by the fractionator 15 is discharged from the drain 20.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. In the figure, reference numeral 1 denotes a cleaning tank, specifically, a pre-cleaning tank 2
And a reduced-pressure cleaning chamber 3 connected to the pre-cleaning tank 2.

The pre-cleaning tank 2 has a front door 5 for feeding a workpiece 4 such as a metal to be cleaned, and a cleaning liquid 6 made of a high-boiling aromatic hydrocarbon compound is provided in a substantially lower half of the inside.
And an elevator (not shown) for immersing the workpiece 4 such as metal fed from the front door 5 into the cleaning liquid 6.
Data is provided. In the figure, reference numeral 7 denotes a heating element provided for shortening the cleaning time.
Heating to 50 degrees or less.

Next, the reduced pressure cleaning chamber 2 is connected to the pre-cleaning tank 2 via an intermediate door 8. The reduced-pressure cleaning chamber 2 is configured to have an airtight structure including the intermediate door 8, and a heating element 9 is provided inside the chamber to shorten the evaporation time of the cleaning liquid 6 attached to the workpiece 4 such as a metal. In the drawing, reference numeral 10 denotes a rear door for taking out a workpiece 4 such as a metal after completion of cleaning.

If the reduced-pressure cleaning chamber 2 has a double-wall jacket structure and hot water or heated air is supplied between the two chambers, the effect of heating the workpiece 4 such as metal is enhanced and the cleaning liquid 6 is condensed and adhered to the inner wall. Thus, the evaporation time of the cleaning liquid can be reduced.

Further, a cleaning liquid purifying and circulating device 11 is connected to the pre-cleaning tank 2. More specifically, a pressure pump 14 for feeding the cleaning liquid 6 to the heater 13 is provided on a pipe 12 provided from the pre-cleaning tank 2. The heater 13 heats the cleaning liquid 6 so that the cleaning liquid 6 is easily vaporized.

Next, following the heater 13, a fractionator 15 for evaporating the heated cleaning liquid 6 in vacuum and fractionating oil is provided. The fractionator 15 is kept warm while heating, and the supplied cleaning liquid 6 is vacuum evaporated to be separated from oil.

Further, following the fractionator 15, a water-cooled condenser 16 for condensing and recovering the evaporated washing liquid 6 is provided.
Is provided. Then, the cleaning liquid 6 recovered by the water-cooled condenser 16 is circulated to the pre-cleaning tank 2 via a pipe 18 by a pressure pump 17. In the figure, 19 is a vacuum pump for discharging the separated gas, and 20 is a drain for discharging the oil separated by the fractionator 15.

Further, a cleaning liquid recovery device 21 is provided from the reduced pressure cleaning chamber 3. More specifically, a water-cooled condenser 23 for condensing and recovering the cleaning liquid 6 evaporated in the reduced-pressure cleaning chamber 3 is provided in a pipe 22 provided from the reduced-pressure cleaning chamber 3, and the separated gas is discharged to the outside by a vacuum pump 24. Configuration.

Further, in the apparatus of the present invention, the cleaning liquid 6 condensed and recovered by the water-cooled condenser 23 is circulated to the pre-cleaning tank 2 via the cleaning liquid purifying and circulating device 11. That is, the pipe 25 provided from the water-cooled condenser 23
Is connected to the pressure feed pump 17. In the figure, reference numerals 26 denote valves which are opened and closed at appropriate times.

FIG. 2 shows a pre-cleaning tank 2 for improving the cleaning efficiency.
In two tanks, and the other parts are the same as in the embodiment of FIG. Further, the cleaning liquid purifying and circulating device 11 may be provided in each pre-cleaning tank 2.

The high-boiling aromatic hydrocarbon compound used as the washing liquid 6 in the present invention has at least one or more, preferably two or more aromatic rings in the molecule, and the boiling point is preferably in degrees Celsius. The temperature is 200 degrees or more, more preferably 250 degrees or more.

The above compounds are provided, for example, under the trade names of "Nisseki Hizol SAS-296" and "Nisseki Hizol SAS-LH" (manufactured by Nippon Petrochemical Co., Ltd.). These compounds are generally liquids produced by synthetic methods using naphtha, etc., which is the main raw material for petrochemicals,
It does not contain any harmful substances such as heavy metals, and its properties are chemically and physically stable, and it is rich in chemical resistance and insulation, and shows excellent solubility and plasticity. The high-boiling aromatic hydrocarbon compound used as the cleaning liquid 6 in the present embodiment is 1
The above-mentioned "Nisseki Hizol SAS-296" containing -phenyl-1-xylylethane as a main component, and the properties thereof are as follows. Existing chemical substance number (4) -38 Appearance Colorless liquid Density (15 degrees Celsius) 0.989 Viscosity (40 degrees Celsius, Cst) 5.0 (100 degrees Celsius, Cst) 1.6 Distillation range (Celsius) 290-305 Flash point (PMCC, Celsius) 150 The product has a high flash point, is safe, and has a characteristic that the distillation range is 15 degrees Celsius so that fractionation is easy. The temperature at which the oil attached to the workpiece 4 such as a metal is washed off is normal temperature, but the heating time can be reduced by heating to enhance the cleaning efficiency. However, in consideration of the cost of the apparatus, the pre-cleaning liquid 6 does not need to be heated.

In the cleaning method using the cleaning liquid 6, the cleaning liquid 6 may be bubbled or agitated in order to enhance the effects of showering and further washing off. May be.

Further, the evaporation of the cleaning liquid 6 in the reduced-pressure cleaning chamber 3 is performed at a temperature of 150 degrees Celsius or less (that is, the tempering temperature of the heat-treated product or less) and 1330 pascal (10 torr).
r) at the following pressures: At this time, as the temperature is higher than the normal temperature, and the pressure is 1330 pascal (10 torr).
The evaporation removal is completed in a shorter time as r) is lower.

At the time of heating in the reduced pressure cleaning chamber 3, it is preferable to stir the atmosphere or the atmosphere gas using a stirring fan to shorten the heating time, and when cleaning hardened steel, the reduced pressure cleaning chamber 3 is used. In this case, the step of evaporating and removing the cleaning liquid 6 and the tempering step can be combined, in which case, the reduced-pressure cleaning chamber may be heated to a temperature suitable for the tempering temperature and maintained for a necessary time.

The cleaning liquid 6 condensed and recovered by the cleaning liquid purifying and circulating apparatus 11 and the cleaning liquid 6 in the pre-cleaning tank 2 are stored in separate recovery tanks and introduced into the pre-cleaning tank 2 only when necessary for cleaning. It may be. Furthermore, by using this recovery tank as two tanks, it can be used for primary cleaning and secondary cleaning separately, the pre-cleaning tank 2 can be used as one tank, and the specification and cost of the cleaning liquid purification and circulation device 11 can be reduced.

[0030]

According to the present invention, an excellent effect can be obtained for washing high-viscosity, low-vapor-pressure oil such as hot-bath quenching oil.
Moreover, a safe and pollution-free effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram of the device of the present invention.

FIG. 2 is a schematic circuit diagram showing another embodiment of the device of the present invention.

[Explanation of symbols]

 2 Pre-cleaning tank 3 Decompression cleaning chamber 4 Workpiece such as metal 6 Cleaning liquid 9 Heating element 11 Cleaning liquid purification circulation device 21 Pre-cleaning liquid recovery device

Continuation of the front page (72) Inventor Hidehisa Torasawa 5-15-20 Tsunashima Nishi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture 5th Kyoei Heim 203 (58) Field surveyed (Int.Cl. ⁷ , DB name) C23G 5 / 02-5/04 B08B 3/08

Claims (3)

(57) [Claims] 1. A method for cleaning a workpiece such as a metal, comprising cleaning a workpiece such as a metal with a cleaning liquid comprising a high-boiling aromatic hydrocarbon compound, and thereafter evaporating and removing the cleaning liquid in a reduced-pressure cleaning chamber. 2. The method according to claim 1, wherein the cleaning of the workpiece such as metal with the cleaning liquid is immersion in the cleaning liquid or spraying of the cleaning liquid. 3. A pre-cleaning tank having a cleaning liquid comprising a high-boiling aromatic hydrocarbon compound, a reduced-pressure cleaning chamber connected to the pre-cleaning tank, having a heating element, and evaporating the cleaning liquid adhered to a workpiece such as a metal. A cleaning liquid purifying and circulating device connected to a cleaning tank and a cleaning liquid collecting device provided from the reduced-pressure cleaning chamber; further connecting the cleaning liquid collecting device to the cleaning liquid purifying and circulating device; A cleaning device for a workpiece such as a metal, which is circulated to the pre-cleaning tank via a through-hole.