JPS6160918B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to an electrodeposition coating apparatus that utilizes a refrigeration/heat pump unit to save energy.

(Prior Art) In conventional electrodeposition coating, for example, in the case of an automobile body frame, etc., a process as shown in FIG. 1 is carried out. In the figure, arrows indicate the direction of heat flow. The product is washed with hot water at 60°C to 65°C (), degreased with hot water at 60°C to 65°C (), washed with water (), and chemically formed () before the base coating is applied. Move on to the step () where electrodeposition coating is performed. In step (), the temperature of the paint solution increases, which reduces the efficiency of electrodeposition, so it is necessary to cool it down. Therefore, a separate refrigerator is currently installed for cooling. Next, the article is finished through a painting (booth) () process and a drying () process. In the prior art, the heating in the () to () steps and the cooling in the () step are performed by separate devices that are not thermally related, so the thermal efficiency is poor and the purpose of energy saving is not met.

In addition, as an improvement measure for the conventional technology as described above,
Japanese Patent Application Publication No. 58-161797 (Patent Application No. 57-41951)
and Japanese Unexamined Patent Publication No. 58-136800 (Japanese Patent Application No. 57-19385)
No.) Some items are in our collection. All of these systems are effective in terms of energy conservation in that a heat pump is installed between the pretreatment tank and the electrodeposition tank, which cools the latter and recovers waste heat by heating the former. However, in the operation of a heat pump, there are still insufficient measures against fluctuations in the load on the electrodeposition tank and fluctuations in outside temperature. In other words, there are measures to be taken when the load on the electrodeposition tank becomes smaller and the amount of heat as a heat source for the heat pump becomes insufficient. Measures to be taken when the temperature of the engine becomes low are not taken into account in the prior art described above, so it is difficult to say that energy saving measures have been sufficiently considered for various operating conditions.

(Problems to be Solved by the Invention) The prior art has various problems as described above. SUMMARY OF THE INVENTION An object of the present invention is to provide an electrodeposition coating apparatus that eliminates the above-mentioned problems by providing a bypass in the heat-absorbing circuit of a heat pump and placing an outside air heat exchanger there.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above-mentioned problems, the electrodeposition coating apparatus of the present invention includes an electrodeposition tank, a refrigeration and heat pump unit that cools a fluid that cools the paint liquid in the electrodeposition tank, an outside air heat exchanger that is installed in a side passage provided in a flow path of the fluid cooled by the refrigeration/heat pump unit and functions as a cooling tower or a heating tower according to changes in the load of the electrodeposition bath; A hot water boiler for heating and raising the temperature of hot water heated by the heat released from the condenser of the heat pump unit, a hot water bath, a degreasing tank, etc. that are heated by the hot water heated and heated by the hot water boiler. It consists of two pre-treatment process tanks.

(Function) The fluid for cooling the paint liquid in the electrodeposition tank is cooled by the refrigeration/heat pump unit, and
The heat absorbed here is released as part of the condensation heat of the unit, and after heating the hot water with the condensation heat, this hot water is further heated and raised in a hot water boiler to obtain hot water of the required temperature. Hot water can be used to heat the hot water in pre-treatment process tanks such as hot water washing tanks and degreasing tanks, and the load on the electrodeposition tank is reduced and the temperature of the fluid flowing out of the heat exchanger is lowered. , a part of the fluid flows into the side passage, and the outside air heat exchanger acts as a heat absorber to prevent the heat source of the unit from being depleted. In addition, when the temperature of the fluid flowing out of the heat exchanger drops and the outside air temperature is lower than that, a part of the fluid flows into the side passage, causing the outside air heat exchanger to act as a radiator, causing the heat pump unit to It is also possible to reduce the temperature of the fluid entering the unit to lighten the load on the unit.

(Example) The present invention will be explained with reference to the embodiment shown in FIG.

1 is an electrodeposition tank, 2 is a hot water washing and degreasing tank, 3 and 4 are heat exchangers, 5 is a refrigeration/heat pump unit, 6 is a hot water boiler, 7 is a cushion water tank, and 8 is a cooling link or heating tower for outside air. heat exchanger, 9
is a load-adjusting hot water tank, which is divided into two chambers by a partition wall 10.
It is divided into 1 and 12. A cycle consisting of a compressor, a condenser, an expansion valve, an evaporator, etc. is formed in the refrigeration/heat pump unit (hereinafter referred to as the "unit") 5, and the evaporator cools water for cooling the electrodeposition tank. The condenser heats hot water for hot water washing and heating the degreasing tank. The cold water leaving the unit 5 at 12° C. flows through the inlet pipe 15 and the three-way switching valve 16 into the cold water pipe 17 of the heat exchanger 3, and cools the paint liquid flowing in the pipe 18. The coating liquid is circulated between the electrodeposition bath 1 and the tube 18 by a pump 19. The water flowing out of the cold water pipe 17 at 17°C passes through the outlet pipe 21, the cushion water tank 7, the return pipe 22, the pump 23, and the return pipe 24 to the unit 5.
Reflux to. The outlet pipe 2 changes depending on the load fluctuation of the electrodeposition tank 1.
The temperature of the water in step 1 goes up and down. In this case, for example, when the load is small and the temperature of the water in the outlet pipe 21 drops, some of the water flows into the side passage 26 and the outside air heat exchanger 8 acts as a heat absorber, absorbing heat from the atmosphere. , through the side passage 27 and into the return pipe 22 so that the amount of heat as a heat source for the heat pump of the unit 5 will not be insufficient. A temperature sensor 28 detects the temperature of the paint liquid and switches the switching valve 16 to bypass the cold water to the side path 20. 29
The temperature detector also detects the chilled water temperature and controls the operation of the unit 5. 25 is a side passage, and 31 to 36 are on-off valves.

Further, when the temperature of the water in the outlet pipe 21 falls below a predetermined temperature (for example, 17°C) and the outside air temperature is lower than that, the water is flowed to the side passage 26 and the outside air heat exchanger 8
By acting as a radiator, the temperature of the water flowing into the unit 5 can be lowered and the load (cooling power) on the unit 5 can be reduced, thereby achieving an energy saving effect.

In the unit 5, the cooling load serves both as a cooling purpose and as a heat absorption source for the heat pump, and the condensed heat serves as a heating source on the heating side and is packaged within the unit 5 to fulfill the above functions. The hot water heated by the heat released from the condenser of the unit 5 flows from the outflow pipe 40 at 60°C through the on-off valve 62, the pipe 58, and the pipe 59 (on-off valve 61 and on-off valve 6).
3 is closed) flows into the hot water boiler 6 and is further heated.
The temperature reaches 65°C and flows through the outflow pipe 60 to the load adjustment hot water tank 9.
The water is stored in the chamber 11, from which it flows into the hot water pipe 46 via the pump 42, the introduction pipe 43, and the switching valve 45.
The hot water flowing inside the pipe 47 is heated. The hot water is circulated between the hot water washing and degreasing tank 2 and the pipe 47 by a pump 48. The hot water flowing out of the outlet pipe 49 at 55°C is stored in the chamber 12 of the load adjustment hot water tank 9, and then pumped 50,
The water flows back to the unit 5 via the inflow pipe 51 and the switching valve 52. 53 is a temperature detector, and 59, 60, and 65 are side channels. Further, a temperature sensor 54 detects the temperature of the hot water and liquid, switches the switching valve 45, and causes the hot water to flow into the side path 55.

In the electrodeposition tank 1, when the temperature of the coating liquid increases, the electrical resistance decreases, current flows more easily, and the current is further converted into heat, causing the temperature to rise and the electrodeposition effect to decrease. On the other hand, if the temperature of the paint liquid is kept low, the electrical resistance increases and the molecular movement of the paint liquid decreases, making it difficult for current to flow through the paint liquid and making it easier for the paint liquid to adhere to metal objects. Therefore, according to this embodiment, the temperature of the paint liquid is
The electrodeposition effect can be enhanced by cooling to about 18°C. Furthermore, since the engine is used as the driving force for the unit 5 and the heat load of its exhaust heat, jacket, and oil cooling are also utilized (not shown), the efficiency of the heat pump can be further increased.

Next, we will discuss the energy saving effect of this example in the third section.
This will be explained using figures. Figure 3 shows the expected heat load pattern required for annual heating and cooling, where the portion above the 0 line is the heating load throughout the year, and the portion below the 0 line is the cooling load throughout the year. The year is 1
Winter from March to April (3 months), midway between April and June (2 months)
It is divided into summer (3 months) from June to September, mid-term (2 months) from September to November, and winter (2 months) from November to January, and calculates the total amount of heat for each period. Each is displayed as a bar graph at the end of each period. Furthermore, since the heating load is at its maximum in the winter, this amount of heat can be reduced to 100
%, and the amount of heat in each other period is shown as a percentage.
Since the cooling load is greatest in the summer, this amount of heat can be reduced to 100
%, and the amount of heat in each other period is shown as a percentage.

When an engine-driven refrigeration and heat pump unit is operated using a cooling load (shaded) below the 0 line as a heat source, the shaded portion of the heating load above the 0 line is obtained as condensation heat. Therefore, it is sufficient to subtract this amount of heat and replenish the amount of heat shown in the white bar graph using the hot water boiler.
By doing so, according to this embodiment, the cooling purpose and the heating purpose can be achieved at the same time, so the efficiency of the unit 5 is doubled, and the fuel used by the hot water boiler 6 can be significantly saved, which is effective in terms of energy saving. Also,
The hot water heated by the unit 5 is not directly introduced into the heat exchanger 4, but the hot water is then introduced into the hot water boiler 6 to further raise the temperature, and then introduced into the heat exchanger 4. , hot water washing, degreasing tank 2
The temperature of the outflow pipe 40 flowing out of the unit 5 can be set to be lower than the temperature of the hot water required for heating the hot water and therefore the required temperature of the hot water flowing through the hot water pipe 46 of the heat exchanger 4. Become. As a result, the temperature difference between the evaporation temperature and the condensation temperature of the refrigerant in the unit 5 can be reduced, and the coefficient of performance of the heat pump can be improved, making it possible to operate the device more effectively in terms of energy conservation.

In addition, an ultrasonic vibration generator 56 is installed in the hot water washing and degreasing tank 2.
By installing an ultrasonic vibration generator 57 in each electrodeposition tank 1 and applying ultrasonic vibration to the liquid in the tank,
Furthermore, the cleaning effect and the effect of electrodeposition coating can be improved. Furthermore, the exhaust gas from the painting (booth) () process and the drying () process are both released into the atmosphere.
A heat pump can also be used for low-temperature drying using a refrigerator in the drying step ().

〔Effect of the invention〕

The fluid for cooling the paint liquid in the electrodeposition tank is cooled by a refrigeration/heat pump unit, and the heat absorbed here is released as part of the condensation heat of the unit, which heats the hot water, which in turn heats the water. By heating and raising the temperature of hot water in a hot water boiler, hot water at the required temperature can be obtained, so hot water in pre-treatment process tanks such as hot water washing tanks and degreasing tanks can be heated with this hot water.

Furthermore, when the load on the electrodeposition bath becomes small and the temperature of the fluid flowing out of the heat exchanger decreases, the outside air heat exchanger in the side passage acts as a heat absorber, making it possible to compensate for the lack of heat source in the unit. Further, when the temperature of the fluid flowing out of the heat exchanger decreases, and the outside air temperature is lower than that, the outside air heat exchanger acts as a radiator to lower the temperature of the fluid flowing into the unit, thereby increasing the temperature of the fluid flowing into the unit. It can also lighten your load.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing the process of electrodeposition coating of automobile body frames, etc. Fig. 2 is a system diagram of an embodiment of the present invention, and Fig. 3 is a system diagram showing the process of electrodeposition coating of an embodiment of the present invention. It is a graph for explaining a heat load pattern and an energy saving effect throughout the year. 1...Electrodeposition tank, 2...Hot water washing and degreasing tank as a pre-treatment process tank, 5...Refrigerating and heat pump unit, 6...Hot water boiler, 8...Outside air heat exchanger, 2
6, 27... Side path, 56, 57... Ultrasonic vibration generator.

Claims (1)

[Scope of Claims] 1. An electrodeposition tank, a refrigeration and heat pump unit that cools a fluid that cools the coating solution in the electrodeposition tank, and a side passage provided in a flow path for the fluid cooled by the refrigeration and heat pump unit. An outside air heat exchanger is installed to serve as a cooling tower or a heating tower according to changes in the load of the electrodeposition tank, and heats and raises the temperature of hot water heated by the heat released from the condenser of the refrigeration and heat pump unit. An electrodeposition coating apparatus comprising: a hot water boiler for heating, a hot water washing tank heated by hot water heated by the hot water boiler, and a pretreatment process tank such as a degreasing tank. 2. The electric power system according to claim 1, which uses an engine to drive a refrigeration/heat pump unit, and utilizes its exhaust heat, heat from a cylinder jacket, etc., to heat and raise/lower hot water heated by a condenser. Coating equipment. 3. The electrodeposition coating apparatus according to claim 1 or 2, wherein the bath is provided with an ultrasonic vibration generator that applies ultrasonic vibrations to the liquid in a hot water washing bath, a degreasing bath, an electrodeposition bath, etc.