JPH0740525Y2 - Degreasing tank water temperature controller - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention relates to a degreasing tank used for pretreatment of electrodeposition coating of automobile bodies, etc. More specifically, the water temperature of the degreasing tank is set to a predetermined value by heat exchange with steam. It relates to a device for keeping the temperature.

The device according to the present invention is mainly installed in a painting factory for automobiles or parts thereof.

(Prior art) Conventionally, in the degreasing process, which is a pretreatment for electrodeposition coating, steam is circulated in order to recover the decrease in the temperature of the degreasing water due to the immersion of the car body and to maintain the water temperature in the degreasing tank constant. However, a method has been adopted in which the heat exchanger is provided outside the degreasing tank, the alkaline degreased water recovered from the tank is passed through the heat exchanger to be heated, and then returned to the degreasing tank again.

(Problems to be solved by the invention) However, during long-term use, the oil component contained in the degreased water gradually adheres and accumulates inside the heat exchanger. It needs to be removed, whether regularly or not. The presence of the adhered oil component is a serious problem that causes a decrease in heat exchange rate and sometimes causes damage to the heat exchanger.

Therefore, conventionally, maintenance is usually performed by periodically disassembling the heat exchanger, cleaning the internal parts of the heat exchanger one by one, and then reassembling the heat exchanger.

However, the series of processes of disassembling, cleaning, and reassembling the heat exchanger is a tedious work and takes a considerable amount of time. Particularly in the plate type heat exchanger, the complexity of such maintenance work was remarkable.

On the other hand, a method may be considered in which a specific chemical liquid that acts to separate oil is passed through the degreasing water passage of the heat exchanger to remove the oil adhering to the inside of the heat exchanger.

Actually, in the surface preparation step and the chemical conversion (phosphoric acid) treatment step belonging to the same pretreatment, there is an example in which the heat exchanger is washed with a chemical solution.

However, in the degreasing process, if a similar method is used by changing the type of chemical liquid, not only a sufficient cleaning effect cannot be obtained due to the nature of the degreasing water, but it may also cause damage to the degreasing tank and its associated pipes. was there.

Therefore, there has been a demand for a means for effectively removing the adhered oil content inside the heat exchanger by a method other than the use of the chemical solution.

The present invention has been made in view of the above circumstances, and an object thereof is to satisfactorily remove oil adhered in the heat exchanger without disassembling, cleaning and reassembling the heat exchanger. It is intended to provide a water temperature control device for a degreasing tank that can be used.

(Means for Solving the Problems) The present invention focuses on the fact that the steam flowing through the heat exchanger attached to the degreasing tank has a considerably large amount of heat (total of sensible heat and latent heat) and is effective in removing oil. Has been completed.

That is, the water temperature control device for a degreasing tank according to the present invention circulates degreased water between the degreasing tank and a heat exchanger outside the tank, passes steam through the heat exchanger, and heat-exchanges the water temperature of the degreasing tank. In the device for maintaining the above, the steam cleaning pipe is branched from the steam inlet pipe to the heat exchanger and is connected to one of the degreasing water inlet pipe or the outlet pipe of the heat exchanger, and the drain pipe is the degreasing water inlet pipe. Alternatively, a switching valve means is provided which is connected to the other of the outlet pipes and further switches the flow of steam from the steam passage of the heat exchanger to the degreased water passage.

In addition to the conventional mechanism for keeping the water temperature in the degreasing tank constant by heat exchange by passing degreased water and steam through a heat exchanger, the device of the present invention exchanges heat with a steam cleaning pipe and a drain pipe together with a switching valve means. It is connected to the pipe outside the device.

The switching valve means is equipped with a suitable number of valves such as a cock valve, a steam cleaning pipe and a drain in order to ensure normal operation for water temperature control and to switch the flow of steam from the steam passage to the degreasing water passage. The pipes are provided in the degreased water inlet pipe, the outlet pipe and the steam inlet pipe, and the outlet pipe of the heat exchanger. Also, in order to adjust the flow rate of the cleaning steam, a flow rate control valve is preferably further attached to the steam inlet pipe or the steam cleaning pipe.

(Operation) In the present invention, when the degreasing process is continued for a long time and the heat exchanger has been operated for a considerable period of time, or when it is considered that a considerable amount of oil has accumulated in the heat exchanger depending on the operating conditions, By switching the valve means, for example, about 130 ° C (heat amount of about 7
(00 kcal / kg) of steam is passed from the steam inlet pipe to the steam cleaning pipe and then to the degreasing water passage of the heat exchanger, and then discharged from the drain pipe through the degreasing water inlet pipe or outlet pipe. Then, the oil that adheres to and remains in the heat exchanger efficiently flows out together with the steam and is discharged from the drain pipe.

Since the heat exchanger is a type 2 pressure vessel, the pressure of the flowing steam is limited to 2.0 kg / cm ² or less.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

The water temperature control apparatus of one embodiment shown in FIG. 1 is related to a degreasing tank 1 for pretreatment of electrodeposition coating, a degreasing water recovery pipe 4, a pump 8, a degreasing water inlet pipe 5, a plate heat exchanger. 2, the degreased water outlet pipe 6 and the degreased water supply pipe 7 are sequentially connected to constitute one circulation system outside the tank, and the pump 8 is operated to remove the degreased water 3
Flows in the direction of arrow p, is recovered from the tank 1, passes through the heat exchanger 2, and is supplied to the tank 1 again. In the heat exchanger 2, for example, steam of about 130 ° C. from the steam source flows through the steam inlet pipe 9, and after heat exchange with the degreased water 3,
It flows out from the steam outlet pipe 10 and is recovered (in the direction of arrow q).
Therefore, the present apparatus can heat the degreased water 3 while circulating it and keep it at a constant temperature.

Moreover, in this embodiment, the steam cleaning pipe 11 is branched from the inlet pipe 9 and connected to the degreasing water outlet pipe 6, and the drain pipe 12 is connected to the degreasing water inlet pipe 5, and the switching valves a to e are steamed. The cleaning pipe 11, the steam inlet pipe 9, the degreased water outlet pipe 6, the degreased water inlet pipe 5 and the drain pipe 12 are provided at appropriate places, and a flow rate control valve 13 is connected to the vapor inlet pipe 9.

Thus, during normal operation for adjusting the water temperature, the valve a,
e is closed and valves b, c and d are open. When cleaning the heat exchanger, the valves a and e are opened and the valves b, c and d are closed to clean the steam from the steam source with a cleaning pipe.
From 11, it is made to flow from the outlet side to the degreased water passage of the heat exchanger 2, and then is made to flow out from the drain pipe 12 via the inlet pipe 5. Then, the residual oil content in the heat exchanger 2 could be efficiently discharged. The flow rate of steam can be adjusted by the balf 13.

FIG. 2 shows a plate heat exchanger 2 according to another embodiment. In this heat exchanger 2, a degreased water inlet pipe 5 and an outlet pipe 6, a steam inlet pipe 9 and an outlet pipe 10 are arranged on one side, and a heat exchange section is supported on a substrate 14 by a guide shaft 15.

In this embodiment, the steam cleaning pipe 11 is branched from the steam inlet pipe 9 and connected to the degreasing water inlet pipe 5, and the drain pipe 12 is attached to the degreasing water outlet pipe 6 so that the steam exchanges heat from the degreasing water inlet side. It is designed to be distributed inside the vessel.

Further, valves f to j are connected to the cleaning pipe 11, the inlet pipe 9, the inlet pipe 5, the outlet pipe 6 and the drain pipe 12 corresponding to the valves a to e.

Other configurations are the same as those in the above-mentioned embodiment.

Thus, during normal operation, the valves f, j are closed and the valves g, h, i are opened. When the heat exchanger 2 is washed, the valves g, h, i are closed and the valves f, j are opened, and the steam is circulated from the inlet side of the heat exchanger 2, the same effect as the above embodiment is obtained. was gotten.

(Effects of the Invention) As described above, the water temperature control device for a degreasing tank according to the present invention can be installed in a heat exchanger of a heat exchanger without frequently performing a series of maintenance processes including disassembly, cleaning, and reassembly of the heat exchanger. The degreased water passage can be washed with steam and the residual oil content can be effectively drained away, so that the maintenance work of the heat exchanger becomes simple and quick.

Moreover, since the device of the present invention utilizes the steam for adjusting the water temperature as it is, it does not require a special chemical liquid for cleaning, that is, removing oil, and is economically advantageous. .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a water temperature adjusting device for a degreasing tank according to an embodiment of the present invention, and FIG. 2 is a diagram showing pipes related to a heat exchanger in the device of another embodiment. In the figure, 1 ... Degreasing tank 2 ... Heat exchanger 3 ... Degreasing water 5 ... Degreasing water inlet pipe 6 ... Degreasing water outlet pipe 9 ... Steam inlet pipe 10 ... Steam outlet pipe 11 ... Steam cleaning Pipe 12 ... Drain pipe a to j ... Valve

Claims (1)

[Scope of utility model registration request] 1. An apparatus for circulating degreasing water between a degreasing tank and a heat exchanger outside the tank, passing steam through the heat exchanger, and keeping the water temperature of the degreasing tank by heat exchange, a steam cleaning pipe is provided. It is provided by branching from the steam inlet pipe to the heat exchanger and connected to one of the degreasing water inlet pipe or outlet pipe of the heat exchanger, and the drain pipe is connected to the other one of the degreasing water inlet pipe or outlet pipe. A water temperature adjusting device for a degreasing tank, further comprising switching valve means for switching the flow of steam from the steam passage of the heat exchanger to the degreasing water passage.