JPH0551289U - Wastewater treatment equipment for dry cleaning machines - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the azeotropic phenomenon and reduce the concentration of the solvent in the evaporated gas in a device that evaporates the wastewater separated from the solvent by aeration and heating. [Structure] In the evaporation tank 1, an outlet 6 for the air for aeration,
A drainage heating means 12 is provided, and a temperature detector 17 is connected to an electromagnetic opening / closing valve 16 for controlling the operation of the heating means 12. The open / close valve 16 is opened / closed by a signal from the temperature detector 17, and the drainage temperature is controlled to be equal to or lower than the azeotropic point.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a wastewater treatment device for evaporating the wastewater of a dry cleaning machine together with the solvent in the wastewater.

[0002]

[Prior Art]

 In a dry cleaning machine, water contained in clothes is mixed with the solvent during the washing process of clothes. The mixed water is separated from the solvent by a water separator and then treated in a wastewater treatment device. ..

As such a wastewater treatment device, an evaporation tank into which wastewater is introduced is provided with an outlet for air for aeration and a heating means for the wastewater to aerate the wastewater and raise the temperature of the wastewater by heating. A structure in which water is discharged as evaporative gas to the next step is considered (eg, Japanese Patent Application No. 3-48561 previously proposed by the applicant).

[0004]

[Problems to be solved by the device]

 By the way, in the treatment structure that uses both aeration and wastewater heating as described above, evaporating efficiency increases when the wastewater temperature is raised, but on the other hand, when the wastewater temperature rises above the azeotropic temperature of water and solvent, azeotropic Due to the phenomenon, there is a problem that the concentration of the solvent contained in the evaporated gas remarkably increases.

The evaporative gas having such a high solvent concentration cannot completely remove the solvent even if it is then passed through an activated carbon tank or the like to adsorb the solvent component and is released to the outside. There are defects that cause harm problems.

Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a treatment apparatus capable of suppressing the solvent concentration in evaporative gas to a low level in a structure in which aeration and drainage heating are used together.

[0007]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention connects an evaporation tank with a passage for introducing wastewater separated from a solvent, and provides an outlet for aeration air and an outlet for evaporated gas at the upper part of the evaporation tank. In the lower part of the evaporation tank, a means for heating waste water and a temperature detector for detecting the waste water temperature are provided, and a control means for controlling the operation of the heating means by a detection signal of the temperature detector is provided. ..

[0008]

[Action]

 In the above structure, the temperature of waste water is detected and the operation of the heating means is controlled so that the waste water temperature becomes equal to or lower than the azeotropic point. By controlling the heating temperature to be low in this way, the azeotropic phenomenon can be prevented and the concentration of the solvent in the evaporative gas can be reduced.

[0009]

【Example】

 FIG. 1 shows a wastewater treatment apparatus of the embodiment. In the figure, 1 is an evaporating tank, 2 is a water separator provided in a solvent recovery circuit of a dry cleaning machine, and a drainage equipped with a pump 5 between a water tank 3 of this water separator 2 and the evaporating tank 1. The introduction passage 4 is connected.

At the upper part of the evaporation tank 1, an air outlet 6 for introducing air for aeration and an outlet 7 for the evaporation gas are provided, and a suction passage 8 connected to this outlet 7 is sucked into the suction passage 8. Blower 9 is provided. A heater 11 to which a steam supply pipe 10 is connected is arranged below the air outlet 6 to heat the air blown from the outlet 6 and supply it to the evaporation tank 1.

Further, a heating means 12 for heating the introduced waste water is provided below the evaporation tank 1. This heating means 12 is composed of a heating plate 13 and a steam pipe 14 installed below the heating plate 13, and a steam supply passage 15 connected to a steam supply source (not shown) is connected to the steam pipe 14 by means of an electromagnetic opening / closing valve 16. Connected through.

A temperature detector 17 for detecting the temperature of the stored waste water is provided below the evaporation tank 1, and the temperature detector 17 controls the opening / closing of the electromagnetic opening / closing valve 16. It is connected to the. The controller 18 is designed so that the azeotropic point temperature can be arbitrarily input from the outside according to the type of solvent, and the azeotropic point temperature is compared with the wastewater temperature detected by the temperature detector 17, The electromagnetic on-off valve 16 is closed when the temperature exceeds an appropriate temperature below the azeotropic point, and the electromagnetic on-off valve 16 is opened when the drainage temperature falls below the above temperature by a certain value or more.

Further, inside the evaporation tank 1, a horizontal separator plate 19 that divides the inside of the evaporation tank into upper and lower parts is provided, and one end of the separator plate 19 faces below the discharge port 7. A partition plate 20 is attached to the other end of the separator plate 19 and extends downward in a direction perpendicular to the separator plate 19.

This embodiment has the above-described structure, and when performing wastewater treatment, the wastewater is introduced into the evaporation tank 1 to a position where a small gap 21 is formed between the partition plate 20 and the liquid surface. ..

In this state, air is introduced from the outlet 6 and steam is supplied to the steam pipe 14 of the heating means 12. The blown air is heated by the heater 11 and then blown into the inside of the separating plate 19 from the gap 21 between the partition plate 20 and the liquid surface to aeration the drainage.

By this aeration and heating by the heating means 12, evaporative gas is generated from the surface of the drainage, and the evaporative gas is guided to the outlet 7 by the separator plate 19 and is discharged to the outside.

In the above-mentioned operation, when the temperature of the waste water rises and the temperature exceeds an appropriate temperature below the azeotropic point of water and the solvent, the controller 18 closes the electromagnetic on-off valve 16 by a signal from the temperature detector 17, The supply of steam to the heating means 12 is stopped. On the contrary, when the drainage temperature falls below the azeotropic point by a certain value or more, the controller 18 opens the electromagnetic opening / closing valve 16 to introduce the steam into the heating means 12 and restart the heating of the drainage. Since it is heated and aerated in a certain temperature range below the azeotropic point, the azeotropic phenomenon is prevented and stable evaporation efficiency can be obtained.

<Experimental Example> Perchlorethylene (azeotropic point: 65 ° C.) is used as a solvent, water is separated from the solvent in a water separator 2, and wastewater having a solvent (perchloroethylene) concentration of 200 ppm or less is evaporated. It was introduced into tank 1. In this state, when aeration was performed while keeping the drainage temperature at 60 ° C., the solvent concentration in the evaporative gas at the outlet 7 was in the range of 2 to 3 ppm.

On the other hand, when the same waste water as the above was aerated at a waste water temperature of 90 ° C., the solvent concentration in the evaporation gas increased to several hundreds to several thousands ppm.

In the above-mentioned embodiment, the solvent adsorption device such as the activated carbon adsorption tank is not attached to the evaporation tank 1, but the activated carbon adsorption tank is connected to the drainage introduction passage 4 or the discharge passage 8 to remove the solvent discharged. The total amount may be suppressed.

Further, the heater 11 for heating the aeration air may be provided inside the air outlet 6.

Further, the wastewater heating means 12 is not limited to the steam heating shown in the figure, but other heating methods such as electric heating can be adopted.

[0023]

【effect】

 As described above, according to the present invention, the temperature of waste water is detected and the waste water temperature due to heating is controlled to be constant, so that the azeotropic phenomenon is prevented, the solvent concentration in the evaporative gas can be lowered, and the environment can be reduced. Efficient wastewater treatment can be performed.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a wastewater treatment device of an embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Evaporation tank 4 Drainage introduction passage 6 Air outlet 7 Discharge port 12 Heating means 16 Electromagnetic on-off valve 17 Temperature detector 18 Controller

Claims (1)

[Scope of utility model registration request] 1. An evaporating tank is connected to a passage for introducing wastewater separated from a solvent, and an outlet for aeration air and an outlet for evaporating gas are provided at the upper part of the evaporating tank, and at the lower part of the evaporating tank. A wastewater treatment apparatus for a dry cleaning machine, comprising a heating means for wastewater and a temperature detector for detecting the temperature of wastewater, and a control means for controlling the operation of the heating means according to a detection signal of the temperature detector.