JPH03126489A - Drying method for pertroleum dry cleaning - Google Patents

Abstract

PURPOSE:To prevent an explosive accident occurring when a petroleum solvent with low flash point is used by reducing pressure of at least a dry path and introducing inert gas to the path in a drying and solvent collecting process. CONSTITUTION:Clothing is housed in a cleaning tank 6, and cleaning is performed by supplying the solvent from a main tank 1 to the cleaning tank 6 rotating at slow speed. After a cleaning process is completed, dehydration is performed by rotating the cleaning tank 6 at high speed. After the dehydration is completed, the cleaning tank 6 is communicated with the dry paths 15-20, and heated air is circulated between the cleaning tank 6 and the dry paths 15-20, and also, an evaporated solvent is collected by condensing with condenser 12. In the drying and solvent collecting process, at least the dry paths 15-20 are evacuated with a vacuum pump 22, and the inert gas is introduced from a gas bomb 23 to the paths. As a result, it is possible to prevent the explosion accident occurring when the petroleum solvent with low flash point is used, and also, to shorten a time required for drying.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for dry cleaning using a petroleum solvent while eliminating the risk of explosion.

[Conventional technology]

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

In Figure 2, 1 is the main tank for solvent.

The solvent in the main tank is circulated from valve 2 → pump 3 → filter 4 → valve 5 → cleaning tank 6 → valve 7 → button trap 8 → main tank 1, and the liquid level in that case is changed to high wave float 9, low liquid The float 10 is set arbitrarily, and the inner body of the washing tank 6 is rotated forward and backward at low speed to perform circulation washing of the clothes in the washing tank.

After the cleaning process is completed, the dirty solvent is sent to a distiller 11 for distillation, the vaporized solvent is condensed by a condenser 12, and the resulting clean solvent is stored in a clean oil tank 14 via a water separator 13. At the same time, the inner shell of the cleaning tank 6 is rotated at high speed to remove liquid, and then the valves 15, 16 are opened and the dust filter 17, fan 18, etc. A drying system path consisting of a drying condenser 19 and a heater 20 is connected to the cleaning tank 6, and a fan 18. The heater 20 and the condenser 19 are driven to circulate the air heated by the heater 20 between the cleaning tank 6 and the drying system to dry the clothes, and the vaporized solvent is condensed by the condenser 19, thus The liquefied solvent is collected in a collection tank 21.

The overall configuration is shown in Figure 1, and there are two types: one that combines a washing/deliquid machine, a dryer, and a distiller for cleaning, and another that has cleaning, deliquid, and drying functions. ,
Generally, the distillation machine is separate.

Regarding this type of dry cleaning, there are JP-A-61-170492 ``Reduced pressure distillation method in dry cleaning'' and JP-A 61-240999 ``Vacuum recovery dryer''.

[Problem to be solved by the invention]

However, petroleum-based solvents have a low flash point of about 41°C, and with conventional technology, as the clothes dry, especially during drying and solvent recovery, the temperature of the clothes rises and the concentration of solvent gas decreases. When the ratio of oxygen to oxygen is 5% to 10%, it becomes easily flammable, and sparks can be caused by static electricity on clothing, or if metal such as a gas lighter enters clothing together with the inner shell and metal, sparks can be generated. There is a risk of the solvent gas igniting and causing an explosion.

The present invention aims to improve the above-mentioned problems and provide a method for washing and drying dry cleaning that can prevent explosion accidents even when using petroleum solvents with low flash points.

[Means to solve the problem]

In order to achieve the above object, the present invention is characterized in that at least during the drying/solvent recovery process, the cleaning tank and the drying system are depressurized and an inert gas is introduced into the system. Note that the pressure reduction and the introduction of the inert gas can also be carried out from the washing step to the drying/solvent recovery step.

[Effect]

As described above, the present invention reduces the pressure in the cleaning tank and the drying system and introduces an inert gas at least in the drying/solvent recovery process, so the reduced pressure shortens the drying time, lowers the oxygen concentration, and By introducing the active gas, the risk of explosion can be eliminated, and the inert gas can serve as a heat medium instead of air to accelerate drying.

〔Example〕

The invention will now be described with reference to FIG.

In the present invention, circulation washing is carried out in the same manner as explained with reference to FIG.
After the Ag, an inert gas such as nitrogen gas is supplied from the gas cylinder 23 to create a vacuum of 150 to 200 mAg and subsequent steps are performed.

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

At this time, the distillation system is vacuumed.

That is, the valves 60, 61, 62, 58 are closed, the valves 57, 52, 51 are opened, and the vacuum pump 50 is turned on to perform distillation at a vacuum level of 600 mHg in the distillation system.

In this way, distillation can be carried out even at low temperatures by lowering the vapor pressure, which is the heat source of the distiller, and the time required for distillation can be shortened.

The distilled solvent is liquefied by a condenser 12, passed through a water separator 13, and collected into a clean oil tank 14. In the subsequent rinsing process, a valve 60 is opened and sent to a cleaning tank 6. The water separated by the water separator 13 is temporarily held in a water tank 56 and drained after the distillation is completed. At this time, the vacuum pump 50 is turned off and the valve 51.5
2 is closed, and valve 61 is open. The solvent used is returned to the main tank 1.

After removing liquid as described above, the drying/solvent recovery process begins, but before that, the inside of the cleaning tank and drying system are pumped with a vacuum pump 2.
After creating a vacuum in step 2, inert gas is supplied from the gas cylinder 23 to start drying with the oxygen concentration lowered.

That is, turn on the vacuum pump 22 (500 to 600 mA
g), turn off the valve 5.7.70.60.
25, open valve 15.16.24, fan 1
8 and the pressure reducing device 25 are turned on, the temperature of the heater 20 is set to approximately 80°C (outlet 50°C), and the chiller water temperature of the drying condenser 19 is set to approximately 13° to 15°C (inlet) to start drying. When the pressure reaches 500 to 600 mAg, an inert gas (for example, nitrogen) is introduced into the system from the gas cylinder 23, and the degree of vacuum is set to 150 to 200 mAg to perform drying and solvent recovery steps.

In this way, inert gas becomes the heat medium instead of air, and since the pressure inside the system is reduced, the vaporization of the solvent contained in the clothes becomes active, reducing the drying time by about 20%. Moreover, the risk of explosion can be completely eliminated.

Incidentally, the time required in the above example was approximately 8 minutes for circulation washing, approximately 5 minutes for rinsing, approximately 5 minutes for dewatering, and approximately 25 minutes for drying, for a total of 43 minutes.

〔Effect of the invention〕

As described above, according to the present invention, at least drying and
In the solvent recovery process, the cleaning tank and drying system are depressurized, which shortens the time required for drying and lowers the oxygen concentration.Introducing an inert gas eliminates the risk of explosion, and the inert gas replaces air. The drying time can be further shortened by acting as a heating medium to accelerate drying.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a dry cleaning apparatus to which the present invention is applied, and FIG. 2 is a block diagram showing a conventional dry cleaning apparatus. 1... Main tank, 3... Pump, 4... Filter, 6... Washing tank, 11... Distiller, 12...
Condenser, 13... Moisture separator, 15.16...
Drying system valve, 17...Dust filter, 18...
Fan, 19...Dry condenser, 20...Heater, 21...Recovery tank, 22.50...Vacuum pump, 23...Gas cylinder.

Claims (1)

[Claims] 1. A cleaning process in which clothes are placed in a washing tank and a solvent is supplied to the washing tank which rotates at a low speed, and a dehydrating process in which the washing tank is rotated at a high speed to remove the liquid after the washing process is completed. and a drying/solvent recovery process in which after the deliquification process is completed, the cleaning tank is communicated with the drying system, heated air is circulated between the cleaning tank and the drying system, and the vaporized solvent is condensed and recovered by a condenser. In the dry cleaning process, at least the drying system is depressurized during the drying and solvent recovery process, and an inert gas is introduced into this system to eliminate the risk of explosion and shorten the drying time. Drying method for petroleum-based dry cleaning. 2. A washing process in which clothes are stored in a washing tank and a solvent is supplied to the washing tank which rotates at a low speed, and a dewatering process in which the washing tank is rotated at a high speed to remove liquid after the washing process is completed. In dry cleaning, a drying/solvent recovery process is performed in which the cleaning tank is communicated with the drying system after completion, heated air is circulated between the cleaning tank and the drying system, and the vaporized solvent is condensed and recovered by a condenser. , after the clothes are placed in the washing tank, the washing tank and the drying system are depressurized, and an inert gas is introduced into this system to perform the washing process, the deliquid process, and the drying/solvent recovery process. A cleaning and drying method for petroleum-based dry cleaning.