JPH07136603A - Cleaning device - Google Patents

Abstract

PURPOSE:To reutilize water and reduce the cost by supplying rinsings to cleaning liquid when the concentration of water in cleaning liquid is measured and the concentration is not exceeding a specific value in a cleaning device in which water-containing cleaning liquid and rinsings after cleaning are used. CONSTITUTION:A print substrate placed on a conveyance conveyor is cleaned by cleaning liquid ejected from a spray nozzle provided in a cleaning chamber. The print substrate is rinsed through a first to a third rinsing chambers and the final rinsing chamber and dried in a drying chamber and thereafter carried out. In the case, the concentration of water in cleaning liquid is measured alternately in the respective tanks 8, 9 by a measuring instrument 24 for the concentration of water. For example, when the concentration of water in the first cleaning tank 8 reaches a value not exceeding preset value, a makeup water valve 28a is opened by a controller 25 and rinsings in a first rinsing tank 10 are supplied. When the water level of the tank 10 is lowered to the water level not exceeding a specified water level, a valve 31 for supplying pure water and a valve 30 for overflow are opened by the output of a low water level sensor 33 and pure water is supplied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device using a water-based cleaning liquid, and more particularly to a cleaning device adapted to be rinsed with water.

[0002]

2. Description of the Related Art Conventionally, when cleaning a printed circuit board or electronic parts, a chlorofluorocarbon-based organic solvent such as CFC or 1.1.1 trichloroethane has been used as a cleaning liquid. These organic solvents can be easily regenerated by distillation.
FIG. 3 is a diagram illustrating a conventional organic solvent cleaning device.
In the figure, 36, 37 and 38 are the first, second and
Final cleaning tank, 39 is a reserve tank for storing the cleaning liquid from the first cleaning tank, 40 is a liquid-sending pump, 41 is a distillation regenerator, 4
3 is a heater for vaporizing the cleaning liquid, 42 is a condensing coil for liquefying, and 44 is a water separator.

As shown in FIG. 3, the cleaning tank is divided into several parts, and the liquid regenerated by distillation by the distillation regenerator 41 is supplied to the final cleaning tank 38, and the cleaning liquids are sequentially supplied to the second and first cleaning tanks 37 and 3.
By overflowing to 6, it was always possible to wash with a new liquid. Further, since it has high volatility, it is possible to perform cleaning with a cleaning liquid alone.

[0004]

However, regarding the chlorine-based organic solvents that have been used conventionally, environmental problems such as ozone depletion in the atmosphere and groundwater pollution have been pointed out in recent years, and their use is prohibited worldwide. There is a direction. Along with this, it has become necessary to switch to another cleaning liquid (alternative cleaning liquid).

However, since most of the alternative cleaning liquids are difficult to regenerate, have poor volatility, and have poor residue reliability, it is necessary to rinse and wash the cleaning liquid with pure water.

In order to stabilize the quality of the object to be cleaned,
Since cleanliness of rinsing water is important, treatment of rinsing water and recycling / reuse are indispensable, which causes a problem of significant increase in cost.

Further, since most of the alternative cleaning liquids are flammable solvents, a method of eliminating the flammability by adding some% of water which is a nonflammable liquid has been adopted. In order to prevent the risk of the above, it is necessary to manage and replenish the water in the cleaning liquid.

However, since the boiling point of water in the cleaning liquid is lower than that of the higher alcohol, which is the main component, the water tends to decrease due to evaporation or the like, and the liquid temperature may be raised to improve the cleaning property.
When the spray cleaning is performed, the water in the cleaning liquid drops in a short time, and there is a problem that it is always necessary to replenish the water.

It is an object of the present invention to provide a cleaning device with reduced cost by reusing water in the cleaning device.

[0010]

In order to achieve the above object, in the present invention, in a cleaning device using a cleaning liquid containing water and rinse water after cleaning, means for measuring the water concentration in the cleaning liquid, When the water concentration is equal to or lower than a predetermined value, a means for replenishing the rinsing water to the cleaning liquid and a means for replenishing a reduced amount of the rinsing water by the replenishment with water are provided.

[0011]

When the moisture concentration measuring device detects a decrease in the water content of the cleaning liquid, it supplies the rinse water from the rinse tank to the cleaning tank. The make-up water is supplied by a method of supplying water until a normal value is obtained by a water concentration measuring device or a method of constantly supplying a constant amount of water with a timer or the like. In the rinse tank, pure water corresponding to the amount of water supplied to the cleaning tank is supplied to the final rinse tank and is sequentially sent to the first rinse tank by an overflow method or a pump method. Since each rinse tank is mixed with water having a lower cleaning solution concentration than the subsequent tanks, the cleaning solution concentration is lowered. As a result, the concentration of the cleaning liquid in the rinsing tank can be always kept low, so that the load on the regenerator is reduced, the industrial waste water discharge amount is reduced, and the cost can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 2 shows the overall configuration of the cleaning apparatus of the present invention, and is a configuration diagram of a printed circuit board cleaning apparatus whose main purpose is flux removal. In the figure, reference numerals 1 and 2 respectively denote a first cleaning chamber and a second cleaning chamber, and a printed board loaded in the direction of an arrow in the drawing and placed on a conveyor 16 is a spray nozzle provided in the cleaning chambers 1 and 2. It is cleaned by the cleaning liquid sprayed from 18. Reference numerals 8 and 9 are first and second cleaning tanks, 20 is a spray pump, and 21 is a filter.

The cleaned printed circuit board is further conveyed by a conveyor 16 to be rinsed through the first rinsing chamber 3, the second rinsing chamber 4, the third rinsing chamber 5, and the final rinsing chamber 6, and then in the drying chamber 7. After being dried by the heater 32, it is carried out. 10, 11, 12, and 13 are the first, second, third, and final rinsing tanks, 14 is a high-concentration water regenerator that regenerates rinse water, and 15 is low-concentration water that regenerates rinse water. The regeneration device 24 includes the first and second cleaning tanks 8,
A water concentration measuring device for measuring the water concentration of 9, a controller 25, a pump 26, 29, a filter 27, a make-up water valve for the first cleaning tank 8, 28a a supply for the second cleaning tank 9. A water valve 31 is a pure water supply valve.

As described above, in the cleaning apparatus of the present invention, the cleaning liquid cleaning section is two tanks (1, 2), the water rinse cleaning section is four tanks (3, 4, 5, 6), and the drying section 7 is provided. It consists of The cleaning liquid is a liquid mainly composed of higher alcohol,
It contains about 7% water to eliminate flammability. The cleaning method is a spray method, and between the first cleaning tank 8 and the second cleaning tank 9, a liquid draining chamber 17 is provided between the first cleaning tank 8 and the second cleaning tank 9 in order to reduce the amount of liquid taken out. In addition, the cleaning liquid may have a temperature of 50 ° C to improve the cleaning property.
The water content in the cleaning liquid is controlled to 60 ° C. and is controlled by a water concentration measuring device 24 installed in the filter ring piping system.

Further, since the cleaning liquid and the water mixed with the cleaning liquid are brought into the rinse water by the substrate, the cleaning jig, the conveyor, etc., the concentration of the cleaning liquid increases every time the cleaning is repeated. Generally, the concentration of the cleaning liquid is highest in the first rinsing bath 10, then becomes lower in the second rinsing bath 11, the third rinsing bath 12 and the subsequent baths. In order to stabilize the quality and reliability of the substrate, the water quality of rinse water is important, and for that purpose, a system for regenerating and reusing water is required.

Therefore, in this embodiment, the first rinsing tank 1 is used.
0, the water containing a high concentration of the cleaning liquid in the second rinse tank 11 is subjected to a regeneration treatment of the rinse water in the high-concentration water regenerator 14 by the distillation method, and the third rinse tank 12 and the final rinse tank 13
The water having a low liquid concentration is rinsed with a low-concentration water regenerator 15 using activated carbon or ion exchange resin.

As described above, the liquid concentration of rinsing water increases little by little with each washing, so the load on the water regenerator gradually increases, increasing the amount of industrial waste water discharged and activated carbon.
Problems such as an increase in the wear rate of the ion exchange resin occur.

The water regeneration system of this embodiment is an example, and the present invention is not limited to this. For example, various methods such as a biological treatment system or a system in which liquid concentration is controlled without using a regenerator are used. The method can be adopted.

FIG. 1 is a diagram showing the detailed construction of the water circulation system in the cleaning apparatus of this embodiment. The operation will be described below with reference to FIG. 1. First, the water concentration in the cleaning liquid is alternately measured by the water concentration measuring device 24 in each tank (8, 9). There is a set value (for example, 5
%) Or less, the water concentration measuring device 24
Signal is output to.

When the controller 25 receives the signal, the controller 25 opens the makeup water valve 28a of the first washing tank 8 in which the water content has dropped, and operates the makeup water pump 26 from the first rinse tank 10. For replenishment, the replenishment time is obtained from the amount of cleaning tank liquid, the amount of replenished water, the pump water supply capacity, etc., and after a certain time has elapsed, the pump 26 is stopped and the valve 28a is closed.

Since the amount of water supplied to the cleaning tank 8 gradually decreases, the water level of the first rinse tank 10 decreases. When the water level drop reaches a certain amount, the low water level sensor 33 detects it and sends a signal to the controller 35. Upon receiving the signal, the controller 35 determines the pure water supply valve 31.
Then, the overflow valve 30 between the third rinse tank 12 and the second rinse tank 11 is opened. As a result, pure water is supplied to the final rinse tank 13 and the overflowed water is sent to the previous tank, so that the water level in the first rinse tank 10 rises. When the water in the first rinsing tank 10 reaches a constant water level, the constant water level sensor 34 detects it and outputs a signal to the controller 35, and the controller 35 closes the pure water supply valve 31 and the overflow valve 30.

As described above, according to the present embodiment, the rinse water mixed with the cleaning liquid is used to replenish the cleaning liquid with water, and the pure water which should be supplied to the cleaning tank is supplied to the final rinse tank. Thus, it is possible to reduce the concentration of the cleaning liquid in the rinsing tank and reduce the load on the water reclamation device and the amount of industrial waste water discharged.

The present invention is not limited to the above-mentioned embodiment, and for example, the makeup water for the cleaning liquid may be supplied from any rinse tank or may be supplied from the water regenerator. Also,
The water supply to the rinse tank may be not only the final rinse tank but other rinse tanks. As the water supply method, various methods such as a method of always supplying a fixed amount of water can be adopted.

[0024]

As described above, according to the present invention, since the rinse water is used for supplying water to the cleaning liquid in response to the decrease in the water concentration of the cleaning liquid, the load on the water regenerator is reduced. In addition, the amount of industrial waste water generated is reduced, which makes it possible to significantly reduce the cost of the water treatment section, which is the most expensive alternative cleaning.

[Brief description of drawings]

FIG. 1 is a diagram showing a detailed configuration of a water circulation system in a cleaning apparatus of the present invention.

FIG. 2 shows the overall configuration of the cleaning apparatus of the present invention.

FIG. 3 is a diagram illustrating a conventional organic solvent cleaning device.

[Explanation of symbols]

 1 1st cleaning room 2 2nd cleaning room 3 1st rinsing room 4 2nd rinsing room 5 3rd rinsing room 6 Final rinsing room 7 Drying room 8 1st rinsing tank 9 2nd rinsing tank 10 1st rinsing tank 11 2nd Rinse tank 12 Third rinse tank 13 Final rinse tank 14 High-concentration water regenerator 15 Low-concentration water regenerator 16 Conveyor conveyor 17 Draining chamber 18 Spray nozzle 19 Air knife 20 Spray pump 21, 23, 27 Filter 22 For filter ring Pump 24 Moisture concentration measuring device 25, 35 Controller 26 Makeup water pump 28a First washing tank make-up water valve 28b Second washing tank make-up water valve 30 Overflow valve 31 Pure water supply valve 32 Heater 33 Low water level sensor 34 Constant water level sensor

Claims (1)

[Claims] 1. A cleaning device using a cleaning liquid containing water and rinse water after cleaning, a means for measuring the water concentration in the cleaning liquid, and the rinsing water containing the cleaning liquid when the water concentration is below a predetermined value. And a means for replenishing the reduced amount of rinse water due to the replenishment with water.