CN110014092B - A mold cooling system and cleaning method - Google Patents

Abstract

The invention relates to a die stamping technology, in particular to a die cooling system and a cleaning method, which comprises an ECU (electronic control unit) controller (1), a water storage cooling tank (2), a normally open electromagnetic valve (3), a cleaning water pump (4), an outlet electromagnetic valve (5), a pressure sensor (6), an outlet temperature sensor (7), a corrugated pipe (8), a die (9), a water channel (10), an inlet temperature sensor (12), an inlet electromagnetic valve (13), an accumulator pressure sensor (14), an accumulator (15), a water pump, a first water pipe (18) and a second water pipe, wherein one end of the first water pipe (18) is communicated with the water storage cooling tank (2) and is respectively connected with the normally open electromagnetic valve (3) and the cleaning water pump (4) in parallel, the other end of the first water pipe is communicated with the inlet of the water channel, the water channel with a coil shape is arranged in the die, the outlet of the water channel, and the first water pipe is connected with a pressure accumulator, an inlet electromagnetic valve and an inlet temperature sensor in series.

Description

A mold cooling system and cleaning method

technical field

The invention relates to die stamping technology, in particular to a die cooling system and a cleaning method.

Background technique

In the prior art, in the hot stamping process of metal products, such as automobile crash beams, since the blank before stamping is heated to a set temperature, it is then put into a pair of dies of a stamping machine, and the blanks are placed in the pair of dies. Pressure is applied to plastically deform the blank to obtain the desired shape of the metal product. The strength and strain resistance of metal products after stamping are improved. In the stamping production process, due to the high temperature of the blank, in the continuous production process, the heat exchange with the mold will make the temperature of the mold exceed the normal value, deform the mold and affect the shape of the stamping part, and even cause the mold to be directly damaged. Therefore, in the existing hot stamping process, a water channel is generally designed in the mold, and the water channel is connected with the external cooling device through a pipeline, so that the heat of the mold is transferred to the mold through the heat exchange between the cooling water in the water channel and the mold. The outside world is dissipated.

In the prior art, there are mainly two ways to dissipate heat from the mold through cooling water: Method 1: The cooling water is continuously sent into the mold by the water pump, so that the cooling water continuously flows through the water channel in the mold. , this process can play a role in cooling the mold; its disadvantage is that no matter the mold is in the process of stamping the blank, or the machine tool is in the process of loading and unloading, the cooling water flows in the mold. In fact, in the three processes of stamping production, loading, stamping, and unloading, there is a part of the time when the temperature of the mold has dropped below the set safe value, and the cooling water still flows in the water channel when the mold does not need heat exchange to cool down. , wasting the power of the pump. Method 2: When the machine tool is in the stamping process, keep the cooling water in the water channel in the mold in a flowing state. When the machine tool is in the loading or unloading stage, cut off the inlet or outlet of the mold water channel, so that the cooling water in the water channel stops flowing. Therefore, the power and energy consumption of the water pump can be saved; the disadvantage is that due to the mold material layer of a certain thickness between the water channel of the mold and the mold surface where the blank is located, when the blank is just placed in the mold, the contact surface between the blank and the mold less heat conduction efficiency, less heat conduction, and slow heating of the mold. After stamping, the blank is plastically deformed and completely adhered to the surface of the mold. At this time, the contact area between the two is maximized, the heat conduction efficiency is high, and the heat conduction is small. However, due to the thickness of the above-mentioned mold material layer, it takes a certain amount of time to pass through the mold material layer to the cooling water channel during the heat transfer process. In addition, the efficiency of stamping automation is high now, and the time from placing the blank in the mold to stamping is very short. Therefore, when the stamping process is completed, a large amount of heat from the blank is transferred to the water channel and heated with the cooling water in the water channel. exchange. If the mold material layer is thicker, when the stamping process is completed and enters the blanking stage, a large amount of heat from the blank is transferred to the water channel and exchanges heat with the cooling water in the water channel. In the second heat dissipation method, when the machine tool is in the stamping process, the water in the water channel is made to flow for rapid heat exchange, and the heat taken away is limited, and when the machine tool is in the loading and unloading stages, the water in the water channel is stopped. The flow will cause a lot of heat to be unable to be exported in time, so that the temperature of the mold will gradually rise, and even exceed the limit value, causing the mold to deform and damage.

There is cooling water in the water channel in the mold for a long time, impurities are easily deposited on the inner wall of the water channel, and scale is formed after a long period of accumulation. The formed scale will affect the heat exchange between the cooling water and the mold. Therefore, the water channel of the mold needs to be descaled. Generally, the descaling agent is poured into the water storage cooling tank to make it pass through the water channel in a circulating flow. The dissolved impurities will be deposited at the bottom of the water storage cooling tank. It has a certain corrosive effect on the mold, water pipe and sealing ring. Therefore, when the descaling process is over, it is necessary to replace the liquid in the water storage cooling tank and use new cooling water to flush the water pipe and water channel to prevent the residue of the descaling agent. This process requires machine downtime, which will affect the normal production activities of the enterprise.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a mold cooling system and a cleaning method that can clean the mold water channel without stopping the machine tool.

The technical solution adopted to solve its technical problems is: a mold cooling system, including an ECU controller, a water storage cooling tank, a normally open solenoid valve, a cleaning water pump, an outlet solenoid valve, a pressure sensor, an outlet temperature sensor, a bellows, a mold , water channel, inlet temperature sensor, inlet solenoid valve, pressure accumulator pressure sensor, pressure accumulator, water pump, water pipe one, water pipe two, one end of the water pipe is connected to the water storage cooling tank and submerged under the liquid surface, and the other end is connected to the water channel The mold is provided with a coil-shaped water channel, the inlet of the water channel is connected with one end of the second water pipe, and the other end of the second water pipe is connected with the water storage cooling tank and submerged below the liquid surface. From the water storage cooling tank to the inlet of the water channel, a water pump, a pressure accumulator, an inlet solenoid valve and an inlet temperature sensor are connected in series on the second water pipe in a sealed series, and the pressure storage port of the pressure accumulator is communicated with the second water pipe and the An accumulator pressure sensor is provided at the connection. The water pump pumps a part of the cooling water from the water storage cooling tank to the accumulator in advance, so that the pressure in the accumulator reaches the upper limit, and the water pump stops working. When the cooling water needs to enter the mold for cooling, the pressure in the accumulator is The cooling water enters the mold through the second water pipe. When the pressure in the accumulator drops to the lower limit, the water pump starts, which can not only maintain the water supply to the mold, but also continue to pump cooling water into the accumulator until the pressure inside the accumulator. pressure reaches the upper limit. The accumulator pressure sensor is used to detect the pressure of the accumulator and transmit the pressure signal to the ECU controller so that it can judge when to start the water pump. From the water storage cooling tank to the outlet of the water channel, a normally open solenoid valve, an outlet solenoid valve, a pressure sensor and an outlet temperature sensor are connected in series on the water pipe in a sealed series, and a cleaning water pump is arranged on one side of the normally open solenoid valve. The cleaning water pump is connected in parallel with the normally open solenoid valve, the cleaning water pump, the outlet solenoid valve, the pressure sensor, the outlet temperature sensor, the inlet temperature sensor, the inlet solenoid valve, the accumulator pressure sensor and the water pump through the pipeline Both are electrically connected to the ECU controller;

Preferably, the ECU controller is also electrically connected with the controlled end of the relay and the positive pole of the 5V power supply, and the control end of the relay is connected in series with the machine tool motor circuit.

Preferably, a corrugated pipe is also included, and the water channel is respectively connected with the first water pipe and the second water pipe through the corrugated pipe.

The technical solution adopted to solve the technical problem is: a cleaning method for a mold cooling system, including the following steps:

First, during the normal cooling cycle of the mold, the ECU controller continuously detects the temperature values measured by the inlet temperature sensor and the outlet temperature sensor, and compares the temperature difference between them;

Secondly, when the machine tool is working normally, if the temperature difference R is less than the set value P, that is, R<P, it means that the impurities deposited on the inner wall of the water channel affect the heat dissipation capacity of the mold, and it is necessary to clean the impurities on the inner wall of the water channel. Subsequent waterway cleaning process;

Furthermore, calculate whether the current cleaning interval from the last waterway cleaning has reached or exceeded the set value. If it has reached or exceeded the set value, the ECU controller will perform the regular cleaning process and enter the subsequent waterway cleaning process;

The water channel cleaning process includes: the ECU controller controls the inlet solenoid valve to close and keeps the outlet solenoid valve open, then energizes the normally open solenoid valve to close it, energizes the cleaning water pump, and turns on the cleaning water pump to pump the cooling water in the left water pipe. into the water storage cooling tank; at this time, the pressure in the water pipe on the left side of the cleaning water pump and in the mold water channel begins to drop, and the ECU controller detects the pressure value of the pressure sensor. When the pressure value is lower than the set value G, the ECU control The controller controls the outlet solenoid valve to close, then stops the cleaning water pump, and powers off the normally open solenoid valve to open it; since the mold is higher than normal temperature during the working process, the cooling water in the water channel is also higher than normal temperature, and when the pressure value in the water channel is low When the set value G is set, a certain degree of vacuum is generated in the water channel, the boiling point of the cooling water is lowered, and a large number of air bubbles are generated in the cooling water in the water channel;

Then, the ECU controller controls the pump to start and generates a certain pumping pressure, and the ECU controller controls the inlet solenoid valve to open, so that the water channel is connected to the water pump and the accumulator, and the pressure in the water channel changes from lower than atmospheric pressure to higher than atmospheric pressure instantly. The water bubbles generated in the cooling water are blasted under the action of the instantaneously increased pressure, and the impact force generated by the blasting will vibrate and scour the inner wall of the water channel, thereby vibrating the impurities deposited on the inner wall of the water channel into the cooling water;

Then, the ECU controller controls the outlet solenoid valve to open, the normally open solenoid valve is still powered off and remains open, the inlet solenoid valve remains open, and under the action of the water pump, the cooling water containing impurities will enter the water storage cooling tank and settle at the bottom , the water intake at the left end of the second water pipe connected to the water pump is located in the upper middle and upper part of the water storage cooling tank, away from the bottom of the water storage cooling tank, but it can ensure that the water intake is always submerged under the liquid level of the water storage cooling tank.

The mold cooling system and the cleaning method of the present invention have the following advantages: the above-mentioned water channel cleaning process can be completed during the working process of the punching machine without the need to stop the punching machine. Compared with the single stamping process including feeding, stamping and unloading, the above-mentioned single cleaning process takes less time. The cleaning process can be inserted into the normal cooling cycle of the mold and will not cause the normal heat dissipation of the mold. influences. As a preference, a certain cleaning interval can be set in the ECU controller, without detecting the inlet temperature sensor and the outlet temperature sensor, the above-mentioned cleaning process is regularly performed on the mold water channel at a certain interval.

Description of drawings

FIG. 1 is a schematic structural diagram of the mold cooling system of the present invention.

Fig. 2 is a schematic diagram of the time state of the operation of the outlet and inlet solenoid valves and the machine tool of the mold cooling system of the present invention.

Description of drawings: 1. ECU controller, 2. Water storage cooling tank, 3. Normally open solenoid valve, 4. Cleaning water pump, 5. Outlet solenoid valve, 6. Pressure sensor, 7. Outlet temperature sensor, 8. Bellows , 9, mold, 10, water channel, 12, inlet temperature sensor, 13, inlet solenoid valve, 14, accumulator pressure sensor, 15, accumulator, 16, water pump, 17, relay, 18, water pipe one, 19, Pipe two.

Detailed ways

As shown in the figure, a mold cooling system includes an ECU controller 1, a water storage cooling tank 2, a normally open solenoid valve 3, an outlet solenoid valve 5, a pressure sensor 6, an outlet temperature sensor 7, a bellows 8, a mold 9, Water channel 10, inlet temperature sensor 12, inlet solenoid valve 13, accumulator pressure sensor 14, pressure accumulator 15, water pump 16, water pipe one 18, water pipe two 19, one end of water pipe one 18 is communicated with water storage cooling tank 2 and is submerged into liquid Below the surface, the other end is in sealing communication with the outlet of the water channel 10, the mold 9 is provided with a water channel 10 in the shape of a coil, the inlet of the water channel 10 is in sealing communication with one end of the second water pipe 19, and the other end of the second water pipe 19 It communicates with the water storage cooling tank 2 and is submerged below the liquid level. From the water storage cooling tank 2 to the inlet of the water channel 10 , the water pipe 2 19 is connected in series with a water pump 16 , an accumulator 15 , an inlet solenoid valve 13 and an inlet temperature sensor 12 in a sealed series. The pressure port is in airtight communication with the second water pipe 19 and an accumulator pressure sensor 14 is provided at the communication place. The water pump 16 pumps a part of the cooling water from the water storage cooling tank 2 to the accumulator 15 in advance, so that the pressure in the accumulator reaches the upper limit value, and the water pump stops working. The cooling water in the pressure accumulator 15 enters the mold through the water pipe 2 19. When the pressure in the accumulator 15 drops to the lower limit, the water pump starts, which can not only maintain the water supply to the mold 9, but also continue to pump into the accumulator 15. Cool the water until the pressure in the accumulator 15 reaches the upper limit value. The accumulator pressure sensor 14 is used to detect the pressure of the accumulator 15, and transmit the pressure signal to the ECU controller, so that it can judge when to start the water pump. From the water storage cooling tank 2 to the outlet of the water channel 10, the water pipe 1 18 is sequentially connected in series with a normally open solenoid valve 3, an outlet solenoid valve 5, a pressure sensor 6 and an outlet temperature sensor 7. There is a cleaning water pump 4 on one side, and the cleaning water pump 4 is connected in parallel with the normally open solenoid valve 3 through the pipeline. The normally open solenoid valve 3, the cleaning water pump 4, the outlet solenoid valve 5, the pressure sensor 6, the outlet temperature sensor 7 , the inlet temperature sensor 12, the inlet solenoid valve 13, the accumulator pressure sensor 14 and the water pump 16 are all electrically connected to the ECU controller 1; the ECU controller 1 is also electrically connected to the controlled end of the relay 17 and the positive pole of the 5V power supply, The control end of the relay 17 is connected in series with the machine tool motor in the same circuit; it also includes a bellows 8, the outlet and the inlet of the water channel 10 are respectively connected with the water pipe 1 18 and the water pipe 2 19 through the bellows 8, so that the die 9 is stamped. During the moving process, the outlet and inlet of the water channel 10 are kept sealed and connected with the first water pipe 18 and the second water pipe 19 respectively. The water storage cooling tank 2 utilizes its heat exchange with the outside air and natural ground to realize heat dissipation of the water stored in it. The normally open solenoid valve 3 remains open when it is not energized, and closes when it is energized. The outlet and inlet solenoid valves are both normally closed solenoid valves, and when it is not energized, it remains closed and opens after it is energized.

The process of mold waterway cleaning is: during the normal cooling cycle of the mold, the ECU controller continuously detects the temperature values measured by the inlet temperature sensor 12 and the outlet temperature sensor 7, and compares the temperature difference between them. When the machine tool is working normally, if the temperature difference R is less than the set value P, that is, R<P, it means that the impurities deposited on the inner wall of the water channel affect the heat dissipation capacity of the mold, and it is necessary to clean up the impurities on the inner wall of the water channel. The waterway cleaning process; at the same time, calculate whether the cleaning interval from the last waterway cleaning has reached or exceeded the set value. If it reaches or exceeds the set value, the ECU controller will perform a regular cleaning process and enter the subsequent waterway cleaning. process. The waterway cleaning process includes: the ECU controller controls the inlet solenoid valve 13 to close and keeps the outlet solenoid valve 5 open, then energizes the normally open solenoid valve 3 to close it, energizes the cleaning water pump 4, and turns on the cleaning water pump 4 to drain the left side water. The cooling water in the pipe is pumped to the water storage cooling tank 2 . At this time, the pressure in the water pipe on the left side of the cleaning water pump 4 and in the mold water channel begins to drop, and the ECU controller detects the pressure value of the pressure sensor 6. When the pressure value is lower than the set value G, the ECU controller controls the outlet solenoid valve. 5 Turn off, then stop cleaning the water pump 4. Power off the normally open solenoid valve 3 to turn it on. Since the mold 9 is higher than normal temperature (25 degrees Celsius) during the working process, the cooling water in the water channel 10 is also higher than normal temperature. When the pressure value in the water channel 10 is lower than the set value G, a certain degree of vacuum is generated in the water channel 10. The boiling point of the cooling water is lowered, and a large number of air bubbles are generated in the cooling water in the water channel 10 . Then, the ECU controller controls the water pump 16 to start to generate a certain pumping pressure, and the ECU controller controls the inlet solenoid valve 13 to open, so that the water channel 10 is communicated with the water pump 16 and the accumulator 15, and the pressure in the water channel 10 is instantly lower than the atmospheric pressure. It becomes higher than the atmospheric pressure, and the water bubbles generated in the cooling water are blasted under the action of the instantaneously increased pressure, and the impact force generated by the blasting will vibrate and scour the inner wall of the water channel 10, thereby removing the impurities previously deposited on the inner wall of the water channel 10. Vibrate into cooling water. Then, the ECU controller controls the outlet solenoid valve 5 to open, the normally open solenoid valve 3 is still powered off and remains open, the inlet solenoid valve 13 remains open, and under the action of the water pump 16, the cooling water containing impurities will enter the water storage cooling tank 2 inside and settle at the bottom. The water intake port at the left end of the water pipe two 19 communicated with the water pump 16 is located in the upper middle part of the water storage cooling tank 2, away from its bottom, but can ensure that the water intake port has not been submerged under the liquid level of the water storage cooling tank 2 all the time. As a preference, a filter is provided at the water intake for filtering impurities in the sucked cooling liquid.

The water channel cleaning method of the present invention does not need to stop the punching machine tool, and can complete the above-mentioned water channel cleaning process during the working process of the punching machine tool. Compared with the single stamping process including feeding, stamping and unloading, the above-mentioned single cleaning process takes less time. The cleaning process can be inserted into the normal cooling cycle of the mold and will not cause the normal heat dissipation of the mold. influences. As a preference, a certain cleaning interval can be set in the ECU controller, without detecting the inlet temperature sensor 12 and the outlet temperature sensor 7, the above-mentioned cleaning process is regularly performed on the mold water channel at a certain interval.

The normal cooling cycle process of the mold refers to: when the machine tool is started, the machine tool motor is energized, the control end of the relay 17 has current passing through, the switch of the controlled end of the relay 17 is closed, and the ECU controller connected to the controlled end of the relay 17 1 pin voltage changes from 0V to 5V, ECU controller 1 judges that the machine tool starts to work, and then controls the inlet solenoid valve 13, outlet solenoid valve 5 and normally open solenoid valve 3 to open; ECU controller 1 according to the accumulator pressure sensor 14 The signal to control the water pump 16, make it cooperate with the accumulator 15, drive the cooling water to circulate among the water pipe two 19, the water channel 10, the water pipe one 18 and the water storage cooling tank 2, and transfer the heat of the mold to the water storage cooling tank 2. Tank 2. The water storage cooling tank 2 utilizes its heat exchange with the outside air and natural ground to realize heat dissipation of the water stored therein.

Taking the above ideal embodiment according to the invention as inspiration, through the above description, relevant staff can make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited. Regarding the content in the specification, the technical scope must be determined according to the scope of the claims.

Claims (1)

1. A cleaning method of a mold cooling system comprises an ECU (electronic control unit) controller (1), a water storage cooling tank (2), a normally open solenoid valve (3), a cleaning water pump (4), an outlet solenoid valve (5), a pressure sensor (6), an outlet temperature sensor (7), a corrugated pipe (8), a mold (9), a water channel (10), an inlet temperature sensor (12), an inlet solenoid valve (13), an accumulator pressure sensor (14), an accumulator (15), a water pump (16), a first water pipe (18) and a second water pipe (19), wherein one end of the first water pipe (18) is communicated with the water storage cooling tank (2) and is submerged below the liquid level, the other end of the first water pipe (18) is communicated with the outlet of the water channel (10), the water channel (10) in a coil shape is arranged in the mold (9), the inlet of the water channel (10) is communicated with one end of the second water pipe (19), and the other end of the second water pipe (19) is communicated with the water storage cooling tank ) A water pump (16), a pressure accumulator (15), an inlet electromagnetic valve (13) and an inlet temperature sensor (12) are sequentially connected on the second water pipe (19) in series in a sealing manner, a pressure accumulation port of the pressure accumulator (15) is communicated with the second water pipe (19), the pressure accumulator pressure sensor (14) is arranged at the communication position, the water pump (16) pumps a part of cooling water from the water storage cooling tank (2) into the pressure accumulator (15) in advance to enable the pressure in the pressure accumulator to reach an upper limit value, the water pump stops working, when the cooling water is required to enter the die for cooling, the cooling water in the pressure accumulator (15) enters the die through the second water pipe (19) and enters the die, when the pressure in the pressure accumulator (15) is reduced to a lower limit value, the water pump is started, water can be supplied to the die (9) and can be continuously pumped into the pressure accumulator (15) until the pressure in the pressure accumulator (15) reaches the upper limit value, the accumulator pressure sensor (14) is used for detecting the pressure of the accumulator (15) and transmitting a pressure signal to the ECU controller, so that it can judge when to start the water pump from the water storage cooling tank (2) to the outlet of the water channel (10), the normally open electromagnetic valve (3), the outlet electromagnetic valve (5), the pressure sensor (6) and the outlet temperature sensor (7) are sequentially connected on the water pipe I (18) in series in a sealing manner, a cleaning water pump (4) is arranged on one side of the normally open electromagnetic valve (3), the cleaning water pump (4) is connected with the normally open electromagnetic valve (3) in parallel through a pipeline, the normally open electromagnetic valve (3), the cleaning water pump (4), the outlet electromagnetic valve (5), the pressure sensor (6), the outlet temperature sensor (7), the inlet temperature sensor (12), the inlet electromagnetic valve (13), the pressure accumulator pressure sensor (14) and the water pump (16) are all electrically connected with the ECU controller (1); the ECU controller (1) is also electrically connected with the controlled end of the relay (17) and the anode of the 5V power supply, and the control end of the relay (17) is connected with a machine tool motor circuit in series; the water channel (10) is connected with the first water pipe (18) and the second water pipe (19) through the corrugated pipe (8);

the method is characterized in that: the cleaning method of the mold cooling system comprises the following steps: firstly, during a normal cooling cycle of the mold, the ECU controller (1) continuously detects temperature values measured by the inlet temperature sensor (12) and the outlet temperature sensor (7), and compares the temperature difference therebetween;

secondly, when the machine tool works normally, if the temperature difference R is smaller than a set value P, namely R < P, the impurities deposited on the inner wall of the water channel influence the heat dissipation capacity of the mold, and the impurities on the inner wall of the water channel are necessary to be cleaned, and then the subsequent water channel cleaning process is carried out;

thirdly, calculating whether the current cleaning interval time from the last time of cleaning the water channel reaches or exceeds a set value, if so, executing a regular cleaning process by the ECU controller, and entering a subsequent water channel cleaning process;

the waterway cleaning process comprises: the ECU controller controls the inlet electromagnetic valve (13) to be closed and keeps the outlet electromagnetic valve (5) open, then the normally open electromagnetic valve (3) is electrified to be closed, the cleaning water pump (4) is electrified, and the cleaning water pump (4) is opened to pump cooling water in the left water pipe into the water storage cooling tank (2); at the moment, the pressure in the water pipe on the left side of the cleaning water pump (4) and the pressure in the water channel of the mold both start to drop, the ECU controller detects the pressure value of the pressure sensor (6), when the pressure value is lower than a set value G, the ECU controller controls the outlet electromagnetic valve (5) to be closed, then the cleaning water pump (4) is stopped, and the normally open electromagnetic valve (3) is powered off to be opened; because the mould (9) is higher than the normal temperature in the working process, the cooling water in the water channel (10) is also higher than the normal temperature, when the pressure value in the water channel (10) is lower than a set value G, a certain vacuum degree is generated in the water channel (10), the boiling point of the cooling water is reduced, and a large amount of bubbles are generated in the cooling water in the water channel (10);

then, the ECU controller controls the water pump (16) to start and generate a certain pumping pressure, the ECU controller controls the opening of the inlet electromagnetic valve (13) to enable the water channel (10) to be communicated with the water pump (16) and the pressure accumulator (15), the pressure in the water channel (10) is instantly changed from being lower than the atmospheric pressure to being higher than the atmospheric pressure, the bubbles generated in the cooling water are blasted under the action of the instantly raised pressure, the impact force generated by blasting can generate vibration and scouring action on the inner wall of the water channel (10), and therefore impurities deposited on the inner wall of the water channel (10) are vibrated to fall into the cooling water;

then, the ECU controller controls the outlet electromagnetic valve (5) to be opened, the normally open electromagnetic valve (3) is still powered off and keeps an open state, the inlet electromagnetic valve (13) keeps open, cooling water containing impurities enters the water storage cooling tank (2) and is precipitated at the bottom under the action of the water pump (16), and a water taking port at the left end of a water pipe II (19) communicated with the water pump (16) is positioned at the middle upper part of the water storage cooling tank (2) and is far away from the bottom of the water storage cooling tank, but the water taking port can be ensured to be always submerged below the liquid level of the water storage cooling tank (2).

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