JPH0649117B2 - Drying method for dry cleaning with flammable solvent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention enables efficient cleaning and drying while eliminating the risk of explosion when performing dry cleaning using a flammable solvent such as a petroleum solvent. It is about the method.

[Conventional technology]

 The configuration of a conventional dry cleaning machine is shown in FIG.

In FIG. 2, reference numeral 1 is a main tank for solvent, and the solvent in the main tank is valve 2 → pump 3 → filter 4 →
Valve 5 → washing tank 6 → valve 7 → send to button trap 8 and the liquid level in that case is high liquid float 9, low liquid float 10
Is set arbitrarily, and the inner body of the cleaning tank 6 is rotated at a low speed in the forward and reverse directions to wash the object to be cleaned in the cleaning tank.

After the cleaning process is completed, the dirty solvent is sent to the distiller 11 for distillation, and the vaporized solvent is condensed by the condenser 12,
The resulting clean solvent is passed through a water separator 13 and a clean oil tank 14
Store in. At the same time, the inner body of the cleaning tank 6 is rotated at high speed to remove liquid, and at that time, the valves 15 and 16 are open,
The cleaning tank 6 is communicated with the drying system path including the dust filter 17, the fan 18, the drying condenser 19, and the heater 20.
Drive the fan 18, heater 20, and condenser 19 to heat the heater 20.
The air heated by is circulated between the cleaning tank 6 and the drying system passage to dry the object to be washed, and the solvent vaporized thereby is condensed by the condenser 19, and the liquefied solvent is watered by the water separator 21. And a solvent, and the solvent is collected in the main tank 1.

In addition, although the entire configuration is shown in FIG. 2, a cleaning and draining machine, a dryer, and a single distiller for cleaning are combined, and a machine having cleaning, draining and drying functions. ,
It is common to have a separate distiller.

However, the petroleum solvent that is generally used as a flammable solvent has a low flash point of about 42 ° C., and in the prior art, as the items to be washed such as clothes dry, especially during drying and solvent recovery. As the temperature of the object to be washed rises and the concentration of solvent gas becomes thin, it becomes easier to ignite when the concentration of the air-fuel mixture is about 1 Vol% to 6 Vol%, and sparks due to static electricity and the inner body when metal is contained. Sparks generated by hitting metal objects may cause solvent gas to ignite and explode.

In order to avoid such an explosion risk, the amount of air in the dryer for dry cleaning is reduced to the amount of air when the degree of vacuum is 210 mmHg to 0 mmHg, and
It is possible to introduce an inert gas into the dryer for dry cleaning and to discharge the air in the dryer until the vacuum amount becomes 210 mmHg to 0 mmHg until the amount of air is equivalent.
No. 224398 is disclosed.

[Problems to be Solved by the Invention]

However, as described in JP-A-62-224398, the amount of air in the dryer is set to a vacuum degree of 210 mmHg to 0 mmHg.
There is a problem in that it takes a long time for the drying because the heat medium of the solvent gas in the drying step becomes insufficient only by reducing the air amount to the amount corresponding to the above.

Further, in the case of the method of discharging the air in the dryer while introducing the inert gas into the dryer, it does not require a long time for drying because the inert gas serves as a heat medium instead of air, 8 to 10 minutes for replacing the inert gas with air (clothes 30
Since it also requires kg throughput), there is a problem that the work efficiency is reduced accordingly.

The present invention can improve the above-mentioned problems of the prior art and prevent an explosion accident even in a solvent having a low flash point, but further, replacement of air with an inert gas is possible. It is an object of the present invention to provide a cleaning and drying method of dry cleaning which can be performed within a short time and can shorten the drying time to improve the working efficiency.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention, at least in the drying / solvent recovery step, reduces the pressure of the cleaning tank and the drying system by a vacuum pump, and then introduces an inert gas into this system. Characterize. The depressurization and the introduction of the inert gas can be performed from the cleaning step to the drying / solvent recovery step.

[Action]

As described above, according to the present invention, at least in the drying / solvent recovery step, since the inert gas is introduced after decompressing the cleaning tank and the drying system passage with the vacuum pump, the air in the cleaning tank and the drying system passage is inert. The gas can be replaced within a short period of time, and the oxygen concentration is reduced by decompression to eliminate the danger of explosion by introducing an inert gas and the inert gas becomes a heat medium instead of air to dry. Can be promoted.

〔Example〕

 The present invention will be described below with reference to FIG.

In the present invention, the cleaning step is performed in the same manner as described with reference to FIG. 2, but before that, the vacuum pump 22 is turned on to set the system to 160 to 260 Torr, and then an inert gas such as nitrogen gas is discharged from the gas cylinder 23. To supply 660 to 760To
The subsequent steps are performed as rr.

When the cleaning is completed, the dirty solvent is sent to the distiller 11 to be purified by distillation, and at the same time, the inner barrel of the cleaning tank 6 is rotated at a high speed to remove the liquid.

Then, the distillation system is evacuated and distilled.

That is, the valves 60, 61, 62, 58 are closed, the valves 57, 52, 51 are opened, the vacuum pump 50 is turned on, and the distillation system is operated at 160T.
Distill as orr. By doing so, it is possible to distill even at a low temperature where the vapor pressure, which is the heat source of the distiller, is lowered, and it is possible to shorten the time required for the distillation.

The distilled solvent is condensed by the condenser 12, passed through the water separator 13 and collected in the clean oil tank 14, and is sent to the cleaning tank 6 by opening the valve 60 in the subsequent rinsing step. The water separated by the water separator 13 is temporarily held in the water tank 56 and drained after the distillation is completed. At this time, the vacuum pump 50 is turned off and the valve 61 is opened. The solvent used for rinsing is returned to the main tank 1.

After the liquid is removed as described above, the drying / solvent recovery step is started. Before that, the cleaning tank 6 and the drying system including the main tank 1 are evacuated by the vacuum pump 22 and then the gas cylinder 23.
Then, an inert gas is supplied to start the drying with the oxygen concentration lowered.

That is, the vacuum pump 22 is turned on (turned off when 160 to 200 Torr is reached), the valves 5 and 60 are closed, and the valves 7, 15, 16 and
With valve 70 open with valve 24 open, the drying system should be 160 to 260 To
When rr is reached, an inert gas (for example, Chisso) is introduced into the system from the gas cylinder 23 via the decompression device 25 to 660-7
The temperature of the heater 20 is set to about 80 ° C. (outlet 50 ° C.), the chiller water temperature of the drying condenser 19 is set to 13 ° to 15 ° C. (inlet), and the fan 18 is driven to perform the drying and solvent collecting steps.

As described above, in the present invention, since the inert gas is introduced after the system is depressurized once, the replacement of the air in the system with the inert gas is substantially the operating time of the vacuum pump (the inert gas (Introduction is instantaneous) For example, in the case of 30Kg of treated clothes,
The air can be replaced with the inert gas in about 1 minute and 30 seconds, and the inert gas can be used as a heat medium instead of air to shorten the drying time, and the risk of explosion is increased. It can be completely lost.

In FIG. 1, the valves 15, 16, 70, 7 are for closing the valves of the cleaning tank 6 when the door of the cleaning tank 6 is opened to prevent gas from flowing into the cleaning tank.

〔The invention's effect〕

As described above, according to the present invention, the risk of explosion is eliminated by introducing the inert gas, and in particular, the introduction of the inert gas is performed in a short time, and the inert gas replaces air. Can be used as a heat medium to accelerate the drying and shorten the time required for the drying, thus improving the working efficiency of the dry cleaning.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a dry cleaning device to which the present invention is applied, and FIG. 2 is a block diagram showing a conventional dry cleaning device. 1 ... Main tank, 2 ... Pump, 4 ... Filter,
6 ... Washing tank, 11 ... Distiller, 12 ... Condenser, 13 ...
… Moisture separator, 15,16 …… Valve, 17 …… Dust filter, 18 …… Fan, 19 …… Dry condenser, 20 …… Heater, 21 …… Moisture separator, 22,50 …… Vacuum pump, 23 ......
Gas cylinder.

Claims (2)

[Claims] 1. A cleaning process in which an object to be cleaned is housed in a cleaning tank and a solvent is supplied to the cleaning tank that rotates at a low speed for cleaning, and a deliquoring process in which the cleaning tank is rotated at a high speed after the cleaning step to drain liquid. After the deliquoring process, the washing tank is connected to the drying system passage, and the heated air is circulated between the washing tank and the drying passage, and the vaporized solvent is condensed and collected by the condenser. In the dry cleaning performed, during the drying / solvent recovery process, the drying system was depressurized by a vacuum pump, and then an inert gas was introduced into this system to eliminate the risk of explosion and shorten the drying time. Drying method of dry cleaning with a characteristic flammable solvent. 2. A washing step in which an object to be washed is housed in a washing tank and a solvent is supplied to the washing tank that rotates at a low speed for washing, and a deliquoring step in which the washing tank is rotated at a high speed after the washing step to remove liquid. After the deliquoring process, the washing tank is connected to the drying system passage, and the heated air is circulated between the washing tank and the drying passage, and the vaporized solvent is condensed and collected by the condenser. In the dry cleaning to be performed, the object to be washed is put in a cleaning tank, the cleaning tank and the drying system passage are closed, and then this passage is decompressed by a vacuum pump, and then an inert gas is introduced into this passage to perform the cleaning. A cleaning and drying method for dry cleaning with a flammable solvent, which comprises performing a process, a liquid removal process, and a drying / solvent recovery process.