JP5303395B2 - Cleaning method and cleaning device - Google Patents

Description

  The present invention relates to a cleaning method and a cleaning apparatus using a cleaning agent such as a hydrocarbon solvent.

  Cleaning agents used for industrial cleaning are required to have excellent cleaning power and high volatility. Detergency is the most important property that affects the finished quality of the product. On the other hand, volatility is related to the workability of the cleaning process and subsequent processes. If the volatility is high, the time required for drying can be saved, and the working efficiency of each process including the cleaning process can be increased. Furthermore, safety, costs related to equipment investment such as a cleaning device, running cost, recyclability, and the like are properties required for the cleaning agent.

  Conventionally, 1,1,1-trichloroethane has been used as a cleaning agent that satisfies these requirements. 1,1,1-Trichloroethane has a high detergency and volatility, is non-flammable, and has a high level of safety for the human body. However, since 1,1,1-trichloroethane is an ozone depleting substance, its production was discontinued in 1995.

  In recent years, hydrocarbon solvents have been frequently used as cleaning agents to replace 1,1,1-trichloroethane. Hydrocarbon solvents are flammable, and there is a problem that the cost for capital investment is high for safe use. However, they are highly compatible with mineral oils such as machine oils and have a detergency against this type of dirt. Are excellent in volatility, and have low volatility and low corrosiveness to metals. Therefore, they are suitable for degreasing and cleaning industrial parts. Furthermore, since oil such as working oil can be easily separated from the solvent by distillation, it is excellent in running cost and recyclability.

  The cleaning apparatus described in Patent Document 1 stores a cleaning agent capable of distillation regeneration such as a hydrocarbon-based solvent in a cleaning tank, immerses the cleaning object in the cleaning tank, and then places the cleaning agent around the cleaning object. Cleaning is performed by forced flow. On the other hand, the cleaning agent contaminated with oil (dirt) adhering to the object to be cleaned is discharged from the cleaning tank, regenerated in the distillation apparatus, and then supplied again to the cleaning tank. By simultaneously cleaning the object to be cleaned and regenerating the cleaning agent in this way, it is possible to prevent the oil mixed in the cleaning agent from re-adhering to the object to be cleaned and to maintain high cleaning power over a long period of time. can do.

JP 07-328567 A

  In recent years, required finishing quality has been increasing in the cleaning of objects to be cleaned. In order to increase the cleaning power of the cleaning agent, it is necessary to reduce the concentration of oil contained in the cleaning agent as an impurity. The oil concentration, which was conventionally managed at around a few percent, is now kept below 1%. However, it is difficult to detect such a small amount of oil from the cleaning agent in real time, and at present, this requirement is satisfied by always performing distillation exceeding a necessary amount.

  However, since distillation takes time, in order to satisfy the above requirement, it is necessary to either lengthen the input interval of the objects to be cleaned to lower the working efficiency or to enlarge the distillation apparatus. Moreover, since an excessive amount is always distilled, a large amount of power is wasted. Recently, environmental problems such as global warming have been screamed, and energy saving is recommended. For this reason, efficient energy operation for the cleaning apparatus is required.

  The problem to be solved by the present invention is to provide a cleaning method and a cleaning apparatus capable of realizing energy saving while maintaining high work efficiency.

The cleaning method according to the present invention made to solve the above problems is a cleaning method for degreasing and cleaning an object to be cleaned with a cleaning agent stored in a cleaning tank.
The oil concentration of the cleaning agent contaminated by the degreasing is measured by an oil concentration measuring means,
A distillation amount of the contaminated cleaning agent necessary for the measured oil concentration to become a control value, and a value of electric power required to distill the contaminated cleaning agent of the distillation amount;
The contaminated cleaning agent is distilled based on the calculated distillation amount and power value.

Furthermore, the cleaning apparatus according to the present invention includes:
A cleaning tank that degreases and cleans an object to be cleaned with a cleaning agent stored inside;
A distillation apparatus for distilling the detergent contaminated by the degreasing;
Oil concentration measuring means for measuring the concentration of oil contained in the contaminated cleaning agent;
Calculate the distillation amount of the contaminated cleaning agent necessary for the measured oil concentration to become a control value, and the value of electric power required to distill the contaminated cleaning agent of the distillation amount, and the calculated distillation amount And distillation apparatus control means for controlling the distillation apparatus based on the power value;
It is characterized by providing.

  As the oil concentration measuring means, an ultraviolet light absorption photometer can be used. Ultraviolet light absorption photometer can measure oil content in a minute amount of detergent below 1% in real time, so it can respond immediately to changes in oil concentration and maintain high cleaning performance. It becomes like this.

  According to the cleaning method and the cleaning apparatus according to the present invention, the concentration of oil contained in the cleaning agent is determined using an ultraviolet light absorption photometer in the case of degreasing cleaning using a cleaning agent capable of distillation regeneration such as a hydrocarbon solvent. The amount of contamination cleaning agent and the amount of electric power required to distill the amount of the contamination cleaning agent are calculated so that the oil concentration becomes the control value given in advance. The distillation apparatus is controlled based on the values. Thereby, the contamination cleaning agent sent to a distillation apparatus can be made into a required minimum quantity, and the energy waste of the whole washing | cleaning apparatus can be suppressed. Furthermore, since the time required for distillation can be shortened by reducing the amount of distillation, the efficiency of the cleaning operation can be increased.

The schematic block diagram which shows one Example of a washing | cleaning apparatus. A graph showing changes in oil concentration and absorbance. The schematic block diagram of a distillation unit control part. The graph (a) showing the change of the oil temperature and distillation amount supplied to a heater, and the graph (b) showing the change of electric power and distillation amount. A graph showing changes in steam evaporation and distillation.

An example of the cleaning apparatus according to the present invention will be described with reference to FIGS.
FIG. 1 is a schematic configuration diagram showing a cleaning apparatus 10 of the present embodiment. The cleaning apparatus 10 includes a first cleaning tank 11, a second cleaning tank 12, an oil concentration monitoring unit (oil concentration measuring means) 13, a storage tank 14, a distillation regeneration unit 15, and a distillation regeneration unit controller (not illustrated). Control means). An ultrasonic vibration oscillator 111 that cleans an object to be cleaned by vibrating a cleaning agent stored in the cleaning tank with ultrasonic waves is installed at the bottom of the bottom surface of the first cleaning tank 11. The object to be cleaned is immersed in the first cleaning tank 11, cleaned by ultrasonic cleaning, and then rinsed by steam cleaning in the second cleaning tank 12. The rinsed object is unloaded from the second cleaning tank 12 and dried to complete the cleaning.

  On the other hand, by ultrasonically cleaning the object to be cleaned, the cleaning agent in the first cleaning tank 11 is contaminated by the oil adhering to the object to be cleaned. The contaminated cleaning agent is discharged from the first cleaning tank 11 to the circulation path 161 and the first recovery path 162. An oil concentration monitoring unit 13 is provided in the middle of the circulation path 161, and the oil concentration of the contaminated cleaning agent passing through the first circulation path is measured in real time. The measured contaminated cleaning agent is again collected in the first cleaning tank 11. On the other hand, the contaminated cleaning agent recovered from the first recovery path 162 is stored in the storage tank 14. The storage tank 14 has a liquid level detection switch, and the inflow and outflow of the contaminated cleaning agent are controlled so that the contamination cleaning agent in the storage tank 14 does not exceed a predetermined amount or less than another predetermined amount.

  The measurement data of the oil concentration by the oil concentration monitoring unit 13 is sent to a distillation regeneration unit control unit (not shown). The distillation regeneration unit control unit calculates a distillation amount and a power value necessary for distillation of the contaminated cleaning agent of the distillation amount according to a method to be described later, and stores the contaminated cleaning agent and power of the distillation amount in the distillation regeneration unit 15. To the distillation column 151. In the distillation tower 151, the contaminated cleaning agent is distilled by a heater, and the cleaning agent and the oil component are separated by the difference in boiling point between the cleaning agent and the oil component. In this embodiment, a cleaning agent having a boiling point lower than that of the oil is used, and the cleaning agent and the oil can be separated by setting the heating temperature of the heater lower than the boiling point of the oil. The oil component separated from the cleaning agent is collected in the oil tank 152. The vaporized cleaning agent branches in two directions by the three-way cock 153, one of which is sent to the condenser 154, condensed and returned to the liquid, and then sent to the circulation tank 156 via the ejector 155. It is sent from 156 to the washing tank 11. The other is sent to the first supply path 163 and supplied to the second cleaning tank 12 by the heater 121 while maintaining the vapor state.

  The steam supplied to the second cleaning tank 12 is used for cleaning the object to be cleaned (rinse) as described above. However, since the object to be cleaned that has been carried into the second cleaning tank 12 has already been cleaned in the first cleaning tank, the cleaning agent in the second cleaning tank 12 is hardly contaminated. Therefore, the cleaning agent after the steam cleaning returns to the liquid in the liquid return tank 122 through the second recovery path 164, and then is supplied to the first cleaning tank 11 through the second supply path 165, and is again to be cleaned. Used for cleaning.

Various methods used in this example will be described below.
(1) Method for Measuring Oil Concentration The oil concentration monitoring unit 13 of this embodiment includes a tank for storing a cleaning agent provided with a viewing window and an ultraviolet light provided at a predetermined distance from the viewing window. It consists of an absorptiometer, and the absorbance of the cleaning agent in the tank is measured through the viewing window to monitor the oil concentration. The ultraviolet light absorptiometer uses HLV-24-UV365 (wavelength 365 nm) manufactured by CCS as an ultraviolet light source and F3UV-A03 manufactured by OMRON as an ultraviolet sensor. The distance between the viewing window and the ultraviolet absorption photometer is 100 mm.

  Next, when hydrocarbon solvent NS100 (made by Japan Energy Co., Ltd.) is used as the cleaning agent, and PG-3080 (press machine oil) is used as the oil mixed in the cleaning agent as impurities, the relationship between the oil concentration and the absorbance Is shown in FIG. In addition, the vertical axis | shaft of FIG. 2 subtracts the measured value of the light absorbency of each oil concentration from the measured value of the light absorbency of a new liquid (oil concentration 0%).

  As shown in FIG. 2, the absorbance measured in accordance with the change in the oil concentration changes almost linearly. Therefore, the oil concentration can be measured by approximating the change in oil concentration and absorbance with a straight line in a preliminary experiment, and substituting the absorbance measured with an ultraviolet light absorptiometer in actual cleaning into this linear approximation. .

(2) Distillation Calculation Method The oil concentration measurement data by the oil concentration monitoring unit 13 is sent to a distillation regeneration unit control unit 20 (not shown in FIG. 1) shown in FIG. The distillation regeneration unit control unit 20 includes a distillation amount calculation unit 21 that calculates a distillation amount necessary to maintain the oil amount at a target concentration from the measured value of the oil concentration sent from the oil concentration monitoring unit 13; The power calculation unit 22 that calculates the value of power necessary for the distillation 151 in the distillation regeneration unit 15 to distill the amount of the contaminated cleaning agent calculated by the distillation amount calculation unit 21 and the power calculation unit 22 calculate And a power supply unit 23 for supplying the power of the power value to the distillation regeneration unit 15. Here, for example, a feedback control system called PID control can be used to calculate the amount of oil in the distillation amount calculation unit 21. In this PID control, an output value for an input value (measured value of oil concentration) and output value (calculated value of oil concentration obtained as a result of distilling a certain amount of distilled detergent) and target value at a certain time. The distillation amount is always recalculated according to the change of the input value so that the residual of the target value becomes zero. Thereby, the distillation amount corresponding to the temporal change of the oil concentration can be calculated. The target value may be given by a predetermined numerical value such as 0.1%, or may be given by a predetermined width such as 0.05% to 0.5%.

(3) Calculation method of power value The relationship between the temperature (oil temperature) of the heater of the distillation tower 151 and the distillation amount, and the relationship between the power supplied to the heater and the distillation amount are shown in (a) and (b) of FIG. As shown, the relationship is almost linear. Therefore, as in the case of oil concentration measurement, a change in power and distillation amount is approximated by a linear function through preliminary experiments and the like, and the distillation amount calculated by the distillation amount calculation unit 21 is substituted into this function. The value of power to be supplied can be calculated.

  The distillation method may be steam heating. In steam heating, the amount of distillation is controlled by changing the steam pressure. For example, if the steam pressure increases by 0.05 MPa, the amount of electric power increases by about 4 kW. Therefore, calculate the amount of electric power for distilling the required amount of contaminated detergent from the relationship between the amount of steam evaporation and the amount of distillation in FIG. Can do.

DESCRIPTION OF SYMBOLS 11 ... 1st washing tank 111 ... Ultrasonic vibration oscillator 12 ... 2nd washing tank 121 ... Heater 122 ... Liquid return tank 13 ... Oil concentration monitoring part 14 ... Storage tank 15 ... Distillation reproduction unit 151 ... Distillation tower 152 ... Oil tank 153 ... Three-way cock 154 ... Condenser 155 ... Ejector 156 ... Circulation tank 161 ... Circulation path 162 ... First recovery path 163 ... Second recovery path 164 ... First supply path 165 ... Second supply path 20 ... Distillation regeneration unit controller 21 ... Distillation amount calculation unit 22 ... Power calculation unit 23 ... Power supply unit

Claims (4)

In the cleaning method of degreasing and cleaning objects to be cleaned with the cleaning agent stored in the cleaning tank,
The oil concentration of the cleaning agent contaminated by the degreasing is measured by an oil concentration measuring means,
A distillation amount of the contaminated cleaning agent necessary for the measured oil concentration to become a control value, and a value of electric power required to distill the contaminated cleaning agent of the distillation amount;
A cleaning method, wherein the contaminated cleaning agent is distilled based on the calculated distillation amount and power value.   2. The cleaning method according to claim 1, wherein the oil concentration measuring means is an ultraviolet light absorptiometer. A cleaning tank that degreases and cleans an object to be cleaned with a cleaning agent stored inside;
A distillation apparatus for distilling the detergent contaminated by the degreasing;
Oil concentration measuring means for measuring the concentration of oil contained in the contaminated cleaning agent;
Calculate the distillation amount of the contaminated cleaning agent necessary for the measured oil concentration to become a control value, and the value of electric power required to distill the contaminated cleaning agent of the distillation amount, and the calculated distillation amount And distillation apparatus control means for controlling the distillation apparatus based on the power value;
A cleaning apparatus comprising:   4. The cleaning apparatus according to claim 3, wherein the oil concentration measuring means is an ultraviolet light absorptiometer.

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