Energy-saving type strip steel cleaning circulating system and control method

Abstract

According to the energy-saving type strip steel cleaning circulating system and the control method thereof, an annular step type overflow circulating system is composed of a plurality of rinsing circulating grooves, and the liquid level heights of the rinsing circulating grooves can be always and stably kept; through a stepped connection method that height difference exists between the rinsing circulating tanks, the water replenishing system can replenish water from the rearmost rinsing circulating tank to the front rinsing circulating tank in a stepped manner; the conductivity of the rinsing circulating tank at the tail end (the last rinsing circulating tank) is detected, when the pollution degree of the rinsed water quality exceeds the standard, automatic discharge is carried out on the first rinsing circulating tank, and then water is supplemented to the first rinsing circulating tank through the following rinsing circulating tanks. According to the invention, the production process of multi-tank single-point discharge and single-point water supplement can be realized, the negative effects of classified control of a plurality of rinsing circulating tanks can be avoided, the discharge amount of pure water and the consumption amount of steam in the adjustment process of the rinsing circulating tanks are reduced, and the energy consumption is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metallurgical machinery / substrate cleaning, and in particular, the present application relates to a cold-rolling continuous production line, a rinsing process for strip steel being arranged in the production line, and more particularly, the present application relates to an energy-saving circulating system for cleaning strip steel and a control method thereof. TECHNICAL BACKGROUND

[0002] A certain continuous annealing and coating production line of a certain company needs to rinse the surface of the strip steel, and then coat insulating paint on the surface of the substrate. Since the coating belongs to a colorless coating, the cleaning effect of the substrate is particularly important.

[0003] However, since the surface of the incoming material has many residual magnesium oxide particles, the production line usually arranges three sets of circulating systems for the rinsing process. As shown in Figure 1 .

[0004] In addition, the invention application with the application number CN200580003030.7 and the invention name "Multi-tank cleaning device and cleaning method" provides a multi-tank cleaning device and a cleaning method which can replace the cleaning liquid without stopping the cleaning operation. The multi-tank cleaning device has a cleaning tank for cleaning the treated object, and at least two rinsing circulating tanks attached to the cleaning tank. The multi-tank cleaning device is characterized in that each rinsing circulating tank has a larger capacity than the cleaning tank, and that a drain line with an on-off valve is provided on each rinsing circulating tank and the cleaning tank. In addition, the cleaning tank and each rinsing circulating tank are connected by a cleaning liquid supply line and a cleaning liquid return line, and an on-off valve is provided on the supply line and the return line. Furthermore, a pump is provided on the downstream side of the on-off valve of the supply line.

[0005] The invention application with the application number CN200710104303.8 and the invention name "High liquid level hot water circulation method for vinyl chloride synthesis conversion system" proposes a high liquid level hot water circulation method for vinyl chloride synthesis conversion system. The application of this method can reduce the use of power equipment, thereby saving energy and reducing consumption, and at the same time, it can eliminate the waste of circulating water tank overflow and expand the capacity of the converter under the same power condition, thereby saving the expansion investment. The main technical feature is that a centrifugal pump is installed on the circulating water outlet header of the converter, and the liquid level difference between the low limit liquid level of the hot water rinsing circulating tank and the liquid level of the conversion system (the highest point that the circulating water can reach when the system is not powered) is greater than or equal to zero, i.e. the low limit liquid level of the rinsing circulating tank is higher than the liquid level of the conversion system.

[0006] However, the essential features shared by this method and existing technologies are: a centrifugal pump as the driving force and an open rinsing circulation tank participating in a non-closed circulation. Its distinguishing technical features from existing technologies are: a centrifugal pump is installed on the main return water pipe of the conversion system; the level difference between the designated lower limit level of the hot water rinsing circulation tank and the conversion system level is greater than or equal to zero, meaning the designated lower limit level of the rinsing circulation tank is set higher than the conversion system level. (Conversion system level refers to the highest point the circulating water can reach when the conversion system is not powered.) (The conversion system includes: a converter, a hot water rinsing circulation tank, converter circulating water inlet and outlet pipes, and the main inlet and return water pipes.)

[0007] Application No. CN201210176207.5, entitled "Piston Aluminum Oxidation Tank Liquid Circulation System," discloses a piston aluminum oxidation tank liquid circulation system, including internal and external circulation. The system comprises a sub-tank, a main tank, a circulation pump connecting the sub-tank and the main tank, and a rinsing circulation tank. The tank liquid treated in the rinsing circulation tank enters the main tank, then flows out from the bottom of the main tank and is partially pumped into the sub-tank. The piston undergoes oxidation in the sub-tank, and the tank liquid overflows from the sub-tank and flows back into the main tank, completing the internal circulation process. A cooling system is connected between the circulation pump and the rinsing circulation tank. The tank liquid flows out from the bottom of the main tank and is partially pumped into a refrigeration system for cooling. The cooled tank liquid flows into the rinsing circulation tank and then back into the main tank, completing the external circulation. A cathode plate and a tank liquid inlet are provided at the bottom of the sub-tank. This piston aluminum oxidation tank liquid circulation system ensures uniform concentration and constant temperature in the sub-tank, resulting in better film formation.

[0008] However, the aforementioned circulation systems are either general cleaning circulation systems that lack content related to liquid level control between multiple tanks, or they are single circulation cleaning systems that cannot solve the problems existing in the aforementioned three circulation systems.

[0009] After use, the following problems were found with the previous system, including the three circulation systems mentioned above:

[0010] 1. The three rinsing circulation systems are all independent systems. Production control requires simultaneous control of the relevant processes of the three systems, which is not conducive to the overall production adjustment and control of the unit.

[0011] 2. Depending on the running direction of the strip steel, the three circulation systems have different requirements for water quality control during the cleaning process. Therefore, the amount of pure water discharged during the adjustment period in actual production is relatively large.

[0012] 3. Each rinsing circulation tank is equipped with a water replenishment system, mainly used to control the liquid level and the cleanliness of the pure water in the rinsing circulation tank; however, because the relevant control interlocks need to be controlled separately, the production personnel need to pay attention to many things during the operation, making the operation inconvenient and the control difficult.

[0013] 4. In addition, during actual production, due to the large amount of residual magnesium oxide dust on the surface of the incoming material, a coating needs to be applied to the strip steel after rinsing. Incomplete rinsing will affect the surface quality of the coating. This results in very high requirements for the water quality of the three rinsing circulation tanks in the rinsing section.

[0014] 5. Furthermore, the pure water in the rinsing circulation tank needs to be heated to a certain process temperature during use. If the three tanks discharge separately, heaters need to be put into each tank during the subsequent water replenishment process, which is not conducive to energy saving. Summary of the Invention

[0015] To address the above problems, the objective of this invention is:

[0016] An energy-saving cleaning strip steel circulation system and its control method are provided. According to the energy-saving cleaning strip steel circulation system and its control method, the production process adopts an energy-saving ring-step overflow circulation system and control method consisting of multiple rinsing circulation tanks.

[0017] The present invention relates to an energy-saving ring-step overflow circulation system and control method for cleaning steel strips.

[0018] It can consistently maintain a stable liquid level in multiple rinsing circulation tanks;

[0019] By using a stepped connection method with height differences between each rinsing circulation tank, the water replenishment system can replenish the water from the last rinsing circulation tank to the front rinsing circulation tank in a stepped manner.

[0020] Conductivity testing of the final rinsing circulation tank (the last rinsing circulation tank) is used to automatically discharge water from the first rinsing circulation tank when the water pollution level exceeds the standard, and then replenish water to the first rinsing circulation tank from the subsequent rinsing circulation tanks.

[0021] By using a similar replenishment method, the undesirable phenomenon of separately discharging water from each rinsing circulation tank can be reduced. This control method is simple and easy to operate, which reduces the amount of water replenished to the rinsing circulation tank and the amount of steam consumed, thus playing a positive role in the stable production of continuous units and reducing energy consumption.

[0022] According to the present invention, the water quality of each rinsing circulation tank in the rinsing circulation system meets the production control specifications. In actual production, no manual discharge is required; automatic discharge, automatic water replenishment, and automatic overflow are achieved through information feedback, greatly improving production efficiency and reducing energy consumption. The method of the present invention is fast, convenient, and highly operable in practical use, ensuring the relative stability of the production process.

[0023] The technical solution of the present invention is as follows:

[0024] An energy-saving circulating system for cleaning steel strips, characterized in that,

[0025] Connect 3-5 rinsing circulation tanks with a height difference to ensure that when the liquid level of the last rinsing circulation tank is greater than the liquid level of the control connection pipe, the water at the higher liquid level will overflow into the previous rinsing circulation tank through the connection pipe, and so on.

[0026] Each rinsing circulation tank has the same volume, and the liquid level in the tank is clearly defined, which facilitates automatic overflow and replenishment during the automatic control process;

[0027] Always maintain the highest liquid level in the last rinsing circulation tank;

[0028] Similarly, when the liquid level in the first rinsing circulation tank is low, the water from the next rinsing circulation tank will be used to replenish the water in the previous rinsing circulation tank.

[0029] According to the present invention, an energy-saving circulating system for cleaning steel strips is characterized in that,

[0030] The last rinsing circulation tank is heated according to the temperature required for cleaning the steel strip.

[0031] According to the present invention, an energy-saving circulating system for cleaning steel strips is characterized in that,

[0032] A manual discharge valve and a solenoid control valve are installed at the bottom of the hot water rinsing circulation tank for manual discharge in case of various abnormal situations, and are normally kept open.

[0033] Preferably,

[0034] The electromagnetic control valve has both "manual" and "automatic" functions, and is in automatic mode during daily production.

[0035] Preferably,

[0036] A manual water supply valve (4) is installed at the top of the last hot water rinsing circulation tank. The manual water supply valve is normally open.

[0037] Preferably,

[0038] Electromagnetic control valve (8): used to control the replenishment of water in the three hot water rinsing circulation tanks. It is always in "automatic" state during normal production. The opening and closing of this valve is determined by the feedback controller (15).

[0039] Preferably,

[0040] An overflow port (11) is set on the first rinsing circulation tank. When too much water is added or the electromagnetic water supply valve is out of control, the liquid level of the last rinsing circulation tank will continue to rise, and the excess water will be discharged out of the tank through the overflow port.

[0041] According to the present invention, an energy-saving circulating system for cleaning steel strips is characterized in that,

[0042] The rinsing circulation tank is equipped with a level gauge (13): the level gauge is a radar level control sensor; it measures the distance by radar wave and has a 4–20mA output signal to send the level data of the rinsing circulation tank to the feedback controller (15) in real time.

[0043] According to the present invention, an energy-saving circulating system for cleaning steel strips is characterized in that,

[0044] A conductivity meter (14) is installed in the last rinsing circulation tank to detect the degree of contamination of the pure water in the last rinsing circulation tank. When the conductivity exceeds the control specification, the feedback controller (15) will send a signal to the electromagnetic discharge valve to open the electromagnetic discharge valve of the first rinsing circulation tank. When the liquid level in the tank drops, the feedback controller (15) sends a signal to the electromagnetic water supply valve (8) to open the water supply, so that the clean pure water is replenished in the last hot water rinsing circulation tank and automatically replenished in the rinsing circulation tank in front.

[0045] According to the present invention, an energy-saving circulating system control method for cleaning steel strip is used, characterized in that:

[0046] Three rinsing circulation tanks are set up, and the liquid level in the third rinsing circulation tank is controlled at 80-85%. When the liquid level in the tank is lower than 80%, the automatic water supply valve (8) will automatically open to supply water. When the liquid level reaches 85%, the automatic water supply valve will automatically close.

[0047] The liquid level in the second rinsing circulation tank is controlled at 75-80%. When the liquid level in the tank is lower than 75%, the automatic water supply valve (8) will automatically open to supply water to the 3# rinsing circulation tank and overflow to the 2# rinsing circulation tank through the connecting pipe. When the liquid level in the 2# rinsing circulation tank reaches 80%, the electromagnetic water supply valve 8 will automatically close.

[0048] The liquid level control height of the first rinsing circulation tank is 70-75%. When the liquid level in the tank is lower than 70%, the automatic water replenishment valve (8) will automatically open to replenish water to the 3# rinsing circulation tank, and overflow to the 2# rinsing circulation tank through the connecting pipe, and then overflow to the 1# rinsing circulation tank through the connecting pipe. When the liquid level height of the 1# rinsing circulation tank reaches 75%, the electromagnetic water replenishment valve 8 will automatically close.

[0049] According to the present invention, a circulating system control method for cleaning steel strip is characterized in that,

[0050] The dirty water is always discharged into the No. 1 rinsing circulation tank.

[0051] This is an effective use of water resources, because the pure water from the No. 2 rinsing circulation tank can be reused in the No. 1 rinsing circulation tank, and the pure water from the No. 3 rinsing circulation tank can be reused in the No. 2 rinsing circulation tank, thus achieving the effect of resource reuse.

[0052] According to the present invention, a circulating system control method for cleaning steel strip is characterized in that,

[0053] According to the product manufacturing process requirements, the conductivity of the water in the last rinsing circulation tank is set and the conductivity is detected. When the contamination level of the pure water in the tank exceeds this value, a logic signal notifies the automatic water replenishment valve of the last rinsing circulation tank to open and continuously overflow into the tanks in front until the last rinsing circulation tank meets the set value requirements. This avoids the drawbacks of separate control for each tank and reduces the amount of pure water discharged from the rinsing circulation tank.

[0054] According to the present invention, a circulating system control method for cleaning steel strip is characterized in that,

[0055] The three rinsing circulation tanks are controlled by a stepped liquid level height, thereby stabilizing the automatic overflow during the water replenishment process, maintaining the stability of the liquid level in the rinsing circulation tanks and the replacement during the water replenishment process.

[0056] According to the present invention, a circulating system control method for cleaning steel strip is characterized in that,

[0057] Each rinsing circulation tank has the same volume, and the liquid level in the tank is clearly defined, which facilitates automatic overflow and replenishment during the automatic control process.

[0058] Preferably,

[0059] The automatic discharge of the No. 1 rinsing circulation tank, the automatic water replenishment of the No. 3 rinsing circulation tank, and the liquid level height of each tank are all controlled by the feedback controller.

[0060] This invention effectively controls the automatic discharge and water replenishment system of the rinsing circulation tank, ensuring that the discharge of dirty water from the rinsing circulation tank is always completed in the No. 1 rinsing circulation tank, and the replenishment of clean water is always completed in the No. 3 rinsing circulation tank. This method reduces the discharge volume and steam heating. The entire control method is simple and requires no manual intervention or maintenance.

[0061] The three rinsing circulation tanks are equipped with a stepped liquid level control system, which can stabilize the automatic overflow during the water replenishment process, maintain the stability of the liquid level in the rinsing circulation tanks, and facilitate water replacement during the water replenishment process.

[0062] The electromagnetic control valve, level gauge, conductivity detector, and other related components involved in this invention are all automatically controlled by a program, and related interlocks are established to achieve level control and cleanliness control of the three rinsing circulation tanks. Attached Figure Description

[0063] Figure 1 This is a simplified diagram of the rinsing circulation system.

[0064] Figure 2 This is a schematic diagram of the rinsing circulation system control of the present invention.

[0065] In the diagram, 1, 2, and 3 are discharge manual valves, 4 is water supply manual valve, 5, 6, and 7 are electromagnetic discharge valves, 8 is an automatic electromagnetic valve, 9 and 10 are connecting pipes, 11 is an overflow port, 12 is a wastewater pit, 13 is a level gauge for the rinsing circulation tank, 14 is a conductivity meter, and 15 is a feedback controller. Detailed Implementation

[0066] Example

[0067] like Figure 2 As shown:

[0068] An energy-saving circulating system for cleaning steel strips and its control method are disclosed. Three rinsing circulation tanks with varying heights are connected. This ensures that when the liquid level in the last rinsing circulation tank is higher than the liquid level in the control connection pipe, the water at the higher level overflows into the previous rinsing circulation tank, and so on. Each rinsing circulation tank has the same volume, and the liquid level within the tank is clearly defined, facilitating automatic overflow and replenishment during automatic control. The last rinsing circulation tank is always kept at the highest liquid level. Similarly, when the liquid level in the first rinsing circulation tank is relatively low, water from the next rinsing circulation tank replenishes the previous one.

[0069] In addition, the manual discharge valves (1, 2, 3) are installed at the bottom of the hot water rinsing circulation tanks 1, 2, and 3 respectively. They are mainly used for manual discharge in case of various abnormal situations and are normally open.

[0070] Electromagnetic control valves (5.6.7): These are installed at the bottom of the hot water rinsing circulation tanks #1, #2, and #3 respectively. They have both "manual" and "automatic" functions and are in automatic mode during daily production.

[0071] Manual water supply valve (4): Installed on top of the No. 3 hot water rinsing circulation tank, and normally in the open state.

[0072] Electromagnetic control valve (8): It is always in "automatic" state during normal production. The opening and closing of this valve is determined by the feedback controller (15). It is a control valve for replenishing water to the three hot water rinsing circulation tanks.

[0073] Connecting pipes (9.10): These are pipes that connect rinsing circulation tanks #1 and #2, and rinsing circulation tanks #2 and #3. Their main function is to supply water to the previous rinsing circulation tank when the liquid level reaches the height of the connecting pipe during the process of replenishing water to rinsing circulation tank #3.

[0074] Overflow port (11): It is installed on the No. 1 rinsing circulation tank. When too much water is added or the electromagnetic water supply valve is out of control, the liquid level of the No. 3 rinsing circulation tank will continue to rise, and the excess water must be discharged out of the tank through the overflow port.

[0075] Wastewater pit (12): mainly for storing wastewater during daily on-site maintenance, so that wastewater can be pumped and recycled by the water treatment department.

[0076] Level gauge (13): Radar level control sensor; it measures distance via radar waves and has a 4–20mA output signal to send the level data of the rinsing circulation tank to the feedback controller (15) in real time.

[0077] Conductivity detector (14): Installed in the No. 3 rinsing circulation tank, mainly to detect the pollution level of pure water in the No. 3 rinsing circulation tank. When the conductivity exceeds the control specification, the feedback controller (15) will send a signal to the electromagnetic discharge valve to open the electromagnetic discharge valve of the No. 1 rinsing circulation tank. When the liquid level of the tank drops, the feedback controller (15) sends a signal to the electromagnetic water supply valve (8) to open the water supply, so that clean pure water is replenished from the No. 3 hot water rinsing circulation tank and automatically replenished to the No. 2 and No. 1 rinsing circulation tanks.

[0078] Feedback controller (15): It is the control element of the entire rinsing cycle system. All solenoid valve discharge and replenishment, liquid level control, etc. are implemented through it.

[0079] The specific control method is as follows:

[0080] A level gauge control method is used to stabilize the liquid levels in the three rinsing circulation tanks. Based on the connection height of the three rinsing circulation tanks, the normal liquid levels of rinsing circulation tanks #1, #2, and #3 are set respectively. Through the principle of automatic water replenishment, it is ensured that the liquid levels in the three rinsing circulation tanks are always within the control specifications. When the liquid level in any rinsing circulation tank falls below the control specification, the automatic water replenishment valve will open to replenish water.

[0081] The liquid level in the 3# rinsing circulation tank is controlled at 80-85%. When the liquid level in the tank is below 80%, the automatic water replenishment valve (8) will automatically open to replenish water. When the liquid level reaches 85%, the automatic water replenishment valve will automatically close.

[0082] The liquid level of the No. 2 rinsing circulation tank is controlled at 75-80%. When the liquid level in the tank is lower than 75%, the automatic water supply valve (8) will automatically open to supply water to the No. 3 rinsing circulation tank and overflow to the No. 2 rinsing circulation tank through the connecting pipe. When the liquid level of the No. 2 rinsing circulation tank reaches 80%, the electromagnetic water supply valve 8 will automatically close.

[0083] The liquid level control height of the 1# rinsing circulation tank is 70-75%. When the liquid level in the tank is lower than 70%, the automatic water replenishment valve (8) will automatically open to replenish water to the 3# rinsing circulation tank, and overflow to the 2# rinsing circulation tank through the connecting pipe, and then overflow to the 1# rinsing circulation tank through the connecting pipe. When the liquid level height of the 1# rinsing circulation tank reaches 75%, the electromagnetic water replenishment valve 8 will automatically close.

[0084] In this embodiment, the method of controlling the cleanliness of pure water by detecting conductivity is used to ensure that the water quality of pure water in the rinsing circulation tank meets the production specifications.

[0085] Based on the actual production situation on site, the water quality requirements for rinsing circulation tanks #1, #2, and #3 are gradually increasing.

[0086] A conductivity meter was installed in the No. 3 rinsing circulation tank to dynamically monitor the cleanliness of the pure water in the No. 3 rinsing circulation tank.

[0087] When the contamination level of the pure water in the No. 3 rinsing circulation tank exceeds the standard, the feedback controller will open the No. 1 rinsing automatic discharge valve to discharge the water. When the liquid level in the tank is lower than 70%, the automatic water replenishment valve of the No. 3 rinsing circulation tank will automatically open and replenish water to the No. 1 rinsing circulation tank through overflow.

[0088] According to this embodiment, manual intervention can also be used to control the discharge and replenishment of water in the three rinsing circulation tanks, thereby adjusting the water quality.

[0089] Switch the solenoid valve at the bottom of the No. 1 hot water rinsing circulation tank to the "manual" state and force it to open for discharge. Then the water supply valve (8) will automatically open to supply water until the liquid level of the three rinsing circulation tanks is within the original set range.

[0090] If the alarm limit of the conductivity meter in the No. 3 rinsing circulation tank is set to be lower than the current detection data, the electromagnetic water supply valve will automatically open to supply water.

[0091] This embodiment features variable control functionality. The liquid level settings and conductivity alarm point settings for each tank can be adjusted according to actual production needs.

[0092] Related interlocking activation conditions in automatic control mode

[0093] The conductivity detector (14) of the 3# rinsing circulation tank detected that the value exceeded the upper limit of the set value, and the solenoid valve (5) of the 1# rinsing circulation tank automatically opened to discharge.

[0094] If any of the liquid levels in the 1#, 2#, or 3# rinsing circulation tanks exceeds the lower limit, the automatic water replenishment valve (8) of the 3# rinsing circulation tank will open to replenish water to the 3# rinsing circulation tank.

[0095] When the liquid level in the 3# rinsing circulation tank exceeds the upper limit of the set value, the automatic water replenishment valve (8) will automatically close.

[0096] The present invention will now be described in detail with reference to Figure 2. The specific control method is as follows:

[0097] A level gauge control method is used to stabilize the liquid levels in the three rinsing circulation tanks. Based on the connection height of the three rinsing circulation tanks, the normal liquid levels of rinsing circulation tanks #1, #2, and #3 are set respectively. Through the principle of automatic water replenishment, it is ensured that the liquid levels in the three rinsing circulation tanks are always within the control specifications. When the liquid level in any rinsing circulation tank falls below the control specification, the automatic water replenishment valve will open to replenish water.

[0098] The liquid level in the 3# rinsing circulation tank is controlled at 80-85%. When the liquid level in the tank is below 80%, the automatic water replenishment valve (8) will automatically open to replenish water. When the liquid level reaches 85%, the automatic water replenishment valve will automatically close.

[0099] The liquid level of the No. 2 rinsing circulation tank is controlled at 75-80%. When the liquid level in the tank is lower than 75%, the automatic water supply valve (8) will automatically open to supply water to the No. 3 rinsing circulation tank and overflow to the No. 2 rinsing circulation tank through the connecting pipe. When the liquid level of the No. 2 rinsing circulation tank reaches 80%, the electromagnetic water supply valve 8 will automatically close.

[0100] The liquid level control height of the 1# rinsing circulation tank is 70-75%. When the liquid level in the tank is lower than 70%, the automatic water replenishment valve (8) will automatically open to replenish water to the 3# rinsing circulation tank, and overflow to the 2# rinsing circulation tank through the connecting pipe, and then overflow to the 1# rinsing circulation tank through the connecting pipe. When the liquid level height of the 1# rinsing circulation tank reaches 75%, the electromagnetic water replenishment valve 8 will automatically close.

[0101] The method of controlling the cleanliness of pure water by using conductivity detection is used to ensure that the water quality of pure water in the rinsing circulation tank meets the production specifications.

[0102] Based on the actual production situation on site, the water quality requirements for rinsing circulation tanks #1, #2, and #3 are gradually increasing.

[0103] A conductivity meter was installed in the No. 3 rinsing circulation tank to dynamically monitor the cleanliness of the pure water in the No. 3 rinsing circulation tank.

[0104] When the contamination level of the pure water in the No. 3 rinsing circulation tank exceeds the standard, the feedback controller will open the No. 1 rinsing automatic discharge valve to discharge the water. When the liquid level in the tank is lower than 70%, the automatic water replenishment valve of the No. 3 rinsing circulation tank will automatically open and replenish water to the No. 1 rinsing circulation tank through overflow.

[0105] Manual intervention can also be used to discharge and replenish water in the three rinsing circulation tanks, thereby adjusting the water quality.

[0106] Switch the solenoid valve at the bottom of the No. 1 hot water rinsing circulation tank to the "manual" state and force it to open for discharge. Then the water supply valve (8) will automatically open to supply water until the liquid level of the three rinsing circulation tanks is within the original set range.

[0107] If the alarm limit of the conductivity meter in the No. 3 rinsing circulation tank is set to be lower than the current detection data, the electromagnetic water supply valve will automatically open to supply water.

[0108] It features variable control functionality. The liquid level settings and conductivity alarm point settings for each tank can be adjusted according to actual production needs.

[0109] Related interlocking activation conditions in automatic control mode

[0110] The conductivity detector (14) of the 3# rinsing circulation tank detected that the value exceeded the upper limit of the set value, and the solenoid valve (5) of the 1# rinsing circulation tank automatically opened to discharge.

[0111] If any of the liquid levels in the 1#, 2#, or 3# rinsing circulation tanks exceeds the lower limit, the automatic water replenishment valve (8) of the 3# rinsing circulation tank will open to replenish water to the 3# rinsing circulation tank.

[0112] When the liquid level in the 3# rinsing circulation tank exceeds the upper limit of the set value, the automatic water replenishment valve (8) will automatically close.

[0113] By consistently discharging dirty water into the No. 1 rinsing circulation tank, water resources are effectively utilized. This is because the pure water from the No. 2 rinsing circulation tank can be reused in the No. 1 rinsing circulation tank, and the pure water from the No. 3 rinsing circulation tank can be reused in the No. 2 rinsing circulation tank, thus achieving the effect of resource reuse.

[0114] Conductivity testing is conducted in the No. 3 rinsing circulation tank, and only in this tank. The control method is mainly determined by the running direction of the strip steel and the cleaning requirements. When the water quality of the No. 3 rinsing tank meets the specifications, there is no need to discharge or adjust the rinsing circulation tank of the previous process, which avoids the drawbacks of classifying and controlling each tank and reduces the amount of pure water discharged from the rinsing circulation tank.

[0115] The three rinsing circulation tanks are equipped with a stepped liquid level control system, which can stabilize the automatic overflow during the water replenishment process, maintain the stability of the liquid level in the rinsing circulation tanks, and facilitate water replacement during the water replenishment process.

[0116] The electromagnetic control valve, level gauge, conductivity detector, and other related components involved in this invention are all automatically controlled by a program, and related interlocks are established to achieve level control and cleanliness control of the three rinsing circulation tanks.

[0117] This "Energy-saving rinsing circulation system and control method" has been successfully used in the subsequent oriented silicon steel 3#FCL unit of a certain company. The on-site operators used it very smoothly. The control method is convenient to operate, simple to control, and has significant effects in actual application, achieving stable rinsing process and optimal cleaning quality for strip steel.

[0118] According to this embodiment, by effectively controlling the automatic discharge and water replenishment system of the rinsing circulation tank, the discharge of dirty water from the rinsing circulation tank is always completed in the No. 1 rinsing circulation tank, and the replenishment of clean water is always completed in the No. 3 rinsing circulation tank. This method of control can reduce the discharge volume and reduce steam heating. The whole control method is simple and requires no manual intervention or maintenance.

[0119] According to this embodiment, the wastewater is always discharged into the No. 1 rinsing circulation tank, which is an effective way to utilize water resources. This is because the pure water in the No. 2 rinsing circulation tank can be used in the No. 1 rinsing circulation tank, and the pure water in the No. 3 rinsing circulation tank can be used in the No. 2 rinsing circulation tank, thus achieving the effect of resource reuse.

[0120] According to this embodiment, conductivity testing is performed in the No. 3 rinsing circulation tank, and the testing is only performed in this tank. The control method is mainly determined by the running direction of the strip steel and the cleaning requirements. When the water quality of the No. 3 rinsing tank meets the specifications, there is no need to discharge or adjust the rinsing circulation tank of the previous process, which avoids the drawbacks of classifying and controlling each tank and reduces the amount of pure water discharged from the rinsing circulation tank.

[0121] This invention effectively controls the automatic discharge and water replenishment system of the rinsing circulation tank, ensuring that the discharge of dirty water from the rinsing circulation tank is always completed in the No. 1 rinsing circulation tank, and the replenishment of clean water is always completed in the No. 3 rinsing circulation tank. This method reduces the discharge volume and steam heating. The entire control method is simple and requires no manual intervention or maintenance.

[0122] The three rinsing circulation tanks are equipped with a stepped liquid level control system, which can stabilize the automatic overflow during the water replenishment process, maintain the stability of the liquid level in the rinsing circulation tanks, and facilitate water replacement during the water replenishment process.

[0123] The electromagnetic control valve, level gauge, conductivity detector, and other related components involved in this invention are all automatically controlled by a program, and related interlocks are established to achieve level control and cleanliness control of the three rinsing circulation tanks.

[0124] According to this embodiment, the on-site operators used it very smoothly. The control method is convenient to operate, simple to control, and has significant effects in actual application, achieving stable strip steel rinsing process and the best cleaning quality.

Claims

1. An energy-saving circulating system for cleaning steel strips, characterized in that, Connect 3-5 rinsing circulation tanks with a height difference to ensure that when the liquid level of the last rinsing circulation tank is greater than the liquid level of the control connection pipe, the water at the higher liquid level will overflow into the previous rinsing circulation tank through the connection pipe, and so on. Each rinsing circulation tank has the same volume, and the liquid level in the tank is clearly defined, which facilitates automatic overflow and replenishment during automatic control. Always maintain the highest liquid level in the last rinsing circulation tank; Similarly, when the liquid level in the first rinsing circulation tank is low, the water from the next rinsing circulation tank will be used to replenish the water in the previous rinsing circulation tank.

2. The energy-saving circulating system for cleaning steel strips as described in claim 1, characterized in that, The last rinsing circulation tank is heated according to the temperature required for cleaning the steel strip.

3. The energy-saving circulating system for cleaning steel strips as described in claim 1, characterized in that, A manual discharge valve and a solenoid control valve are installed at the bottom of the last rinsing circulation tank for manual discharge in case of various abnormal situations. They are normally in the open state. A manual water supply valve (4) is installed at the top of the last rinsing circulation tank. The manual water supply valve is normally open. An overflow port (11) is set on the first rinsing circulation tank. When too much water is added or the electromagnetic water supply valve is out of control, the liquid level of the last rinsing circulation tank will continue to rise, and the excess water will be discharged out of the tank through the overflow port.

4. The energy-saving circulating system for cleaning steel strips as described in claim 1, characterized in that, The rinsing circulation tank is equipped with a level gauge (13): the level gauge is a radar level control sensor; it measures the distance by radar wave and has a 4–20mA output signal to send the level data of the rinsing circulation tank to the feedback controller (15) in real time.

5. The energy-saving circulating system for cleaning steel strips as described in claim 1, characterized in that, A conductivity meter (14) is installed in the last rinsing circulation tank to detect the degree of contamination of the pure water in the last rinsing circulation tank. When the conductivity exceeds the control specification, the feedback controller (15) will send a signal to the electromagnetic discharge valve to open the electromagnetic discharge valve of the first rinsing circulation tank. When the liquid level in the tank drops, the feedback controller (15) sends a signal to the electromagnetic water supply valve (8) to open the water supply, thereby replenishing the last hot water rinsing circulation tank with clean pure water and automatically replenishing the rinsing circulation tank in front.

6. A method for controlling an energy-saving circulating system for cleaning steel strip, using the circulating system described in any one of claims 1-5, characterized in that, Set up 3 rinsing circulation tanks, 1-3# rinsing circulation tanks, and control the liquid level height of the third rinsing circulation tank to 80-85%; when the liquid level in the tank is lower than 80%, the automatic water replenishment valve (8) will automatically open to replenish water; when the liquid level reaches 85%, the automatic water replenishment valve will automatically close. The liquid level in the second rinsing circulation tank is controlled at 75-80%. When the liquid level in the tank is lower than 75%, the automatic water supply valve (8) will automatically open to supply water to the 3# rinsing circulation tank and overflow to the 2# rinsing circulation tank through the connecting pipe. When the liquid level in the 2# rinsing circulation tank reaches 80%, the electromagnetic water supply valve 8 will automatically close. The liquid level control height of the first rinsing circulation tank is 70-75%. When the liquid level in the tank is lower than 70%, the automatic water replenishment valve (8) will automatically open to replenish water to the 3# rinsing circulation tank, and overflow to the 2# rinsing circulation tank through the connecting pipe, and then overflow to the 1# rinsing circulation tank through the connecting pipe. When the liquid level height of the 1# rinsing circulation tank reaches 75%, the electromagnetic water replenishment valve 8 will automatically close.

7. The energy-saving circulating system control method for cleaning steel strip as described in claim 6, characterized in that, The dirty water is always discharged into the No. 1 rinsing circulation tank.

8. The energy-saving circulating system control method for cleaning steel strip as described in claim 6, characterized in that, According to the product manufacturing process requirements, the conductivity of the water in the last rinsing circulation tank is set and the conductivity is detected. When the contamination level of the pure water in the tank exceeds this value, a logic signal notifies the automatic water replenishment valve of the last rinsing circulation tank to open and continuously overflow into the tanks in front until the last rinsing circulation tank meets the set value requirements. This avoids the drawbacks of separate control for each tank and reduces the amount of pure water discharged from the rinsing circulation tank.

9. The energy-saving circulating system control method for cleaning steel strip as described in claim 6, characterized in that, The three rinsing circulation tanks are controlled by a stepped liquid level height, thereby stabilizing the automatic overflow during the water replenishment process, maintaining the stability of the liquid level in the rinsing circulation tanks and the replacement during the water replenishment process.

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