Automatic gage pickling system control method

Abstract

The application discloses an automatic sample plate pickling system control method, belonging to the field of control. Liquid level detection devices are arranged in acid and alkali liquid recovery tanks respectively; a water receiving tray position detection device is arranged in a liquid recovery switching system; a wastewater neutralization tank is arranged at the outlet end of the acid liquid recovery tank and the alkali liquid recovery tank; a pH measuring instrument is arranged in the wastewater neutralization tank; a PLC is arranged, and the PLC is automatically controlled to open and close motors, acid and alkali resistant water pumps, pipeline electromagnetic valves, air pumps and other equipment according to programs, so as to complete sample plate pickling operation, waste liquid neutralization operation, acid preparation operation and acid mist tower discharge operation. The sample plate pickling operation, the waste liquid neutralization operation, the acid preparation operation and the acid mist tower discharge operation are integrated into an automatic operation system through the PLC, so that the pickling operation efficiency is improved, the operation intensity is reduced, the pickling quality of the sample plate is ensured, and personal safety and operation safety coefficient in pickling operation and acid replacement operation are ensured. The application is suitable for the field of cold-rolled base plate pickling operation in hot-rolled production.

Description

Technical Field

[0001] This invention belongs to the field of control, and particularly relates to a control method for an automatic pickling system for cold-rolled sheet samples. Background Technology

[0002] Currently, Baosteel's hot rolling mill uses a traditional acid pickling method for its three production lines.

[0003] The acid pickling operation uses hydrochloric acid (HCl) as the pickling medium. Its main component is hydrogen chloride (>30%). It is an acidic corrosive substance with strong irritant properties, which is harmful to the environment and can pollute water bodies. The neutralization medium is industrial soda ash (alkali powder).

[0004] To ensure that the pickling quality of hot-rolled samples is consistent with that of cold-rolled pickling mill steel plates, relevant pickling operation methods have been developed in the production process.

[0005] (1) Pickling operation of the sample:

[0006] For sample pickling, wearing appropriate pickling protective gear, manually use pliers to place the sample into the pickling tank. The movements must be gentle to avoid acid splashing, and the pickling time must be controlled to meet the 5-minute requirement. Manually use pliers to place the sample into the alkaline water tank for neutralization. After the sample is placed in the neutralization tank, the pickling tank cover must be closed immediately. For sample cleaning, manually use pliers to place the sample into the clean water tank for cleaning.

[0007] (2) Preparation of acid and alkali solutions:

[0008] When preparing acid solution, follow the principle of adding water first and then acid. Hydrochloric acid must be slowly poured into the acid tank along the acid guide plate to prevent acid from splashing and causing injury. Use 6 barrels (60 liters) of hydrochloric acid each time. When preparing alkali solution, dilute it with soda ash in clean water before use. Use 4 kg of soda ash each time.

[0009] (3) Discharge of acid:

[0010] The residual waste acid / alkali / cleaning liquid in the tank is simultaneously discharged into the waste liquid pool. If the pH value displayed by the pH meter is found to be outside the range of 6-9, it is neutralized with acid and alkali to the range of 6-9 before being discharged. (Because the alkali powder is sodium carbonate, a weak alkali substance that is not easily dissolved in water, the pH value is tracked for 24 hours). The discharge destination is the sludge dewatering system.

[0011] (4) Acid mist emission:

[0012] Acid mist is extracted by the exhaust equipment, neutralized in the acid mist scrubbing tower, and then discharged. The pH value displayed by the pH meter of the acid mist scrubbing tower must be within the range of 6-9 before discharge. If the pH value is found to be exceeding the standard, the scrubbing tower must be neutralized to the range of 6-9 before exhaust. When the pH value displayed by the pH meter of the acid mist scrubbing tower is <6 or >9, the purified water in the acid mist scrubbing tower must be replaced.

[0013] During the pickling and acid replacement processes described above, a large amount of acid mist and acid splashes are generated. Although ventilation equipment is installed on site to reduce the harm of acid mist to the human body, the acid mist can still cause physical harm to the operators when they come into contact with it.

[0014] It is evident that existing pickling operations suffer from numerous shortcomings, including low efficiency, high workload, and significant safety risks during pickling and acid replacement.

[0015] How to improve the efficiency of pickling operations, reduce their intensity, and ensure the safety of workers during pickling, neutralization, and acid replacement operations are urgent technical problems that need to be solved in practice. Summary of the Invention

[0016] The technical problem to be solved by this invention is to provide an automatic sample pickling system control method. This method integrates sample pickling, waste liquid neutralization, acid preparation, and acid mist scrubbing tower discharge into a single automatic operating system via a computer (PLC). By setting, calculating, and controlling within the PLC, the workflow is optimized to ensure the quality of sample pickling and the safety of the operation. After receiving steel coil information from the pickling sample from the upper-level computer L2, the PLC selects the pickling time according to the pre-set program and parameters, and automatically pickles the sample. During the pickling process, set detection devices, such as limit switches, ultrasonic level gauges, radar level gauges, and pH meters, provide the PLC with data such as position information, liquid level, and pH measurement values. The PLC then calculates according to the program and issues commands to start or stop motors, acid and alkali resistant water pumps, pipeline solenoid valves, air pumps, and other equipment to complete the sample pickling, waste liquid neutralization, acid preparation, and acid mist scrubbing tower discharge operations.

[0017] The technical solution of this invention is: to provide an automatic sample pickling system control method, including setting up an pickling tank with three functions of pickling, neutralization and cleaning, and a pickling tank cover that can be opened and closed; the pickling sample is cleaned in the pickling tank by switching different liquid media to complete the three operations of pickling, neutralization and cleaning; a liquid recovery switching system and a corresponding liquid recovery system are set below the pickling tank; the corresponding liquid recovery system includes an acid recovery tank, an alkali recovery tank and a clean water recovery tank; corresponding to the acid recovery tank, alkali recovery tank and clean water recovery tank, an acid replenishment circuit, an alkali replenishment circuit and a clean water replenishment circuit are respectively set up, and the replenishment circuit includes at least a corresponding delivery pump and a pipeline solenoid valve set at the outlet of the delivery pump; the pickling tank is also connected to the acid mist tower pipeline; its characteristic is:

[0018] Liquid level detection devices are installed in the acid recovery tank and the alkali recovery tank respectively;

[0019] A position detection device for the water receiving tray is installed in the liquid recovery switching system;

[0020] Wastewater neutralization tanks are installed at the outlets of the acid and alkali recovery tanks; pH meters are installed in the wastewater neutralization tanks.

[0021] Set up a PLC to receive position signals, pH values, and liquid level information from the position detection device, pH meter, and liquid level detection device;

[0022] After receiving the steel coil information of the pickling sample from the upper-level computer L2, the PLC selects the pickling time according to the pre-set program and parameters, and automatically pickles the sample. During the pickling process, the location information, liquid level and pH measurement data are provided to the PLC through various detection devices. The PLC then calculates according to the program and issues the start or stop of the motor, acid and alkali resistant water pump, pipeline solenoid valve, air pump and other equipment to complete the sample pickling operation, waste liquid neutralization operation, acid preparation operation and acid mist tower discharge operation.

[0023] The sample pickling operation, waste liquid neutralization operation, acid preparation operation, and acid mist scrubbing tower discharge operation are integrated into an automatic operating system through PLC. By setting, calculating and controlling in the PLC, the operation process is optimized, the pickling efficiency is improved, the work intensity is reduced, and the pickling quality of the sample is ensured, as well as the personal safety and operational safety factor during pickling and acid replacement operations.

[0024] The pickling methods mentioned include rapid pickling, normal pickling, and long-term pickling.

[0025] Specifically, the pickling time in the rapid pickling, normal pickling, and long-term pickling modes can be selected through automatic and manual selection modes.

[0026] Furthermore, the control method for the automated sample pickling system operates according to the following steps:

[0027] 1) After the PLC system receives the relevant information about the sample to be pickled from the production process control computer L2, once the sample enters the pickling tank, the PLC issues a command to activate the first and second cylinders to close the cover. At the same time, it also issues a command to rotate the lead screw motor. After the PLC receives the limit A signal, it issues the corresponding start-up time of the acid recovery tank water pump according to the winding temperature. When the acid recovery tank water pump starts, the solenoid valve A of the acid recovery tank pipeline opens and the solenoid valve B of the acid recovery tank pipeline closes, so that the acid flows from the acid recovery tank to the pickling tank and then back to the acid recovery tank, making it a cycle.

[0028] 2) After pickling is completed, once all the acid has flowed into the acid recovery tank, the PLC sends a command to rotate the lead screw motor. After the PLC system receives the signal from limit B, it sends another command to start the water pump in the alkali recovery tank. At the same time, it also sends a signal to open the solenoid valve A in the alkali recovery tank pipeline and close the solenoid valve B in the alkali recovery tank pipeline, so that the alkali flows from the alkali recovery tank to the pickling tank and then back to the alkali recovery tank, making it a cycle.

[0029] 3) After neutralization, once all the alkaline solution has flowed into the alkaline solution recovery tank, the PLC sends a command to rotate the lead screw motor. After the PLC system receives the limit switch C signal, it sends another command to start the water pump in the clean water recovery tank. At the same time, it also sends a signal to open the solenoid valve A of the clean water recovery tank pipeline and close the solenoid valve B of the clean water recovery tank pipeline, so that the clean water flows from the clean water recovery tank to the pickling tank and then back to the clean water recovery tank, making it a cycle, and the entire pickling operation is completed.

[0030] 4) The PLC system calculates the liquid level displayed by the ultrasonic level gauge in the waste liquid neutralization tank based on the neutralization ratio of the acid washing medium and the alkaline washing medium. It then combines this with the liquid level displays from the radar level gauge in the acid recovery tank, the ultrasonic level gauge in the alkaline recovery tank, and the ultrasonic level gauge in the clean water recovery tank to calculate how much the liquid level in each of the three recovery tanks should be lowered. After calculating the results, the PLC system starts the water pumps in the acid recovery tank, the alkaline recovery tank, and the clean water recovery tank. Simultaneously, it opens solenoid valves B in the acid recovery tank, alkaline recovery tank, and clean water recovery tank pipelines, and closes solenoid valves A in the acid recovery tank, alkaline recovery tank, and clean water recovery tank pipelines.

[0031] When the liquid levels in the three recovery tanks are lower than the calculated remaining liquid level, the ultrasonic level gauge in the waste liquid neutralization tank sends a feedback to the PLC system after the liquid level reaches 70% of the tank's volume. The PLC system then issues a shutdown order for the pumps in the acid recovery tank, alkali recovery tank, and clean water recovery tank, while waiting for the pH meter in the waste liquid neutralization tank to send the current pH value back to the PLC.

[0032] If the pH value of the waste liquid neutralization tank is too acidic, turn on the water pump of the alkali recovery tank;

[0033] If the pH value of the waste liquid neutralization tank is too alkaline, turn on the acid recovery tank water pump;

[0034] If the pH value of the waste liquid neutralization tank is in the range of 6-9, the PLC issues a command to open the solenoid valve of the waste liquid neutralization tank, discharge the wastewater into the wastewater pool, and repeat the operation several times until all the wastewater in the three recycling tanks is neutralized.

[0035] 5) During acid preparation, the PLC first obtains level information from the radar level gauges of the acid recovery tank, the ultrasonic level gauges of the alkali recovery tank, and the ultrasonic level gauges of the clean water recovery tank. Then, the acid and alkali media are prepared in ratios of 1:1.2 and 1:5.4 respectively, so that the concentration of the acid media reaches approximately 15% and the concentration of the alkali media reaches approximately 5%. The total amount prepared reaches approximately 90% of the volume of the acid or alkali recovery tank. Finally, the PLC issues commands to activate the water pumps of the acid storage tank, alkali storage tank, and clean water tank, as well as the solenoid valves of the acid storage tank pipeline, alkali storage tank pipeline (Solenoid Valve B), and clean water tank pipeline (Solenoid Valve B). Close the solenoid valves A of the alkali storage tank pipeline, A of the acid mist tower alkali replenishment pipeline, A of the clear water storage tank pipeline, A of the filter tower water replenishment pipeline, and A of the acid mist tower water replenishment pipeline. The liquid level information is fed back to the PLC via the radar level gauge and ultrasonic level gauge of the acid recovery tank and alkali recovery tank. When the calculated liquid level is reached, the PLC issues a switching solenoid valve command to replenish water to the acid recovery tank and alkali recovery tank to dilute the concentration. The water pumps of the acid storage tank and alkali storage tank are then turned off. Once the liquid levels fed back by the radar level gauge, ultrasonic level gauge, and ultrasonic level gauge of the clear water recovery tank reach the calculated levels, the water replenishment system is shut off, and the acid preparation operation is complete.

[0036] 6) When the acid mist tower and filter tower are working normally, the exhaust fan motor and the acid mist tower spray pump are in the on state, and the solenoid valves of the acid mist tower water supply pipeline, acid mist tower alkali supply pipeline, filter tower water supply pipeline, acid mist tower wastewater discharge solenoid valve, and filter tower wastewater discharge solenoid valve are in the closed state. The ultrasonic level gauge of the filter tower, the ultrasonic level gauge of the acid mist tower, and the pH detector of the acid mist tower monitor the liquid level and pH of the acid mist tower and filter tower in real time.

[0037] When the liquid level is low, the PLC will issue a water replenishment command, and the water pump in the storage tank will open the relevant solenoid valve of the acid mist tower water replenishment pipeline, or the solenoid valve of the filter tower water replenishment pipeline will also open; when the liquid level reaches the preset value, the PLC will issue a command to close the water pump in the storage tank, the solenoid valve of the acid mist tower water replenishment pipeline, and the solenoid valve of the filter tower water replenishment pipeline.

[0038] When the pH detector of the acid mist tower detects that the pH value of the acid mist tower exceeds the specified value, the PLC will issue a brief but continuous command to open the water pump of the alkali storage tank and the solenoid valve of the alkali replenishment pipeline of the acid mist tower. Each time it is opened for 10 seconds, it will stop for 1 minute. After the pH detector of the acid mist tower detects that the pH value of the acid mist tower is within the specified range, the PLC will issue a command to close the water pump of the alkali storage tank and the solenoid valve of the alkali replenishment pipeline of the acid mist tower.

[0039] When the media in the acid mist tower and filter tower reach the upper limit of the service life, the PLC issues an opening command to the solenoid valve for wastewater discharge from the acid mist tower and the filter tower. After the media in the acid mist tower and filter tower are discharged into the waste liquid neutralization tank, the water replenishment operation is performed again.

[0040] Furthermore, the wastewater neutralization adopts a batch neutralization mode, with the neutralization target value calculated based on a pH value of 7.5, and the maximum neutralization value set at 70% of the water level limit in the wastewater neutralization tank.

[0041] The automatic sample pickling system described in this invention optimizes the workflow and ensures the pickling quality and safety of the samples by setting, calculating and controlling the system in a PLC.

[0042] Compared with the prior art, the advantages of the present invention are:

[0043] 1. This technical solution uses an acid pickling tank with three functions: pickling, neutralization, and cleaning. By switching between different pipes and solenoid valves, three types of liquid cleaning are performed to complete the three operations of pickling, neutralization, and cleaning.

[0044] 2. This technical solution uses a liquid recovery and switching system (with a movable water receiving tray and related limit positioning) to recover different liquids separately; it can automatically neutralize and discharge waste liquid, improving the efficiency of pickling operations, reducing the intensity of operations, and ensuring the personal safety and operational safety of operators in pickling and acid change operations.

[0045] 3. This technical solution also includes a waste liquid neutralization tank, which consists of a tank body, a pH meter, an ultrasonic level gauge, and pipelines. It can automatically neutralize and discharge waste liquid, ensuring the safety of operators during pickling and acid replacement operations.

[0046] 4. This technical solution completes the three operations of pickling, neutralization, and cleaning by switching between different liquid media. At the same time, a reciprocating liquid recovery and switching system recovers the different liquids separately. Waste liquid can be automatically neutralized and discharged, which improves the efficiency of pickling operations, reduces the intensity of operations, and ensures the personal safety and operational safety of operators in pickling and acid replacement operations. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the hardware piping of the automatic pickling system of the present invention;

[0048] Figure 2 This is a partial enlargement of the automatic pickling system of the present invention. Figure 1 ;

[0049] Figure 3 This is a partial enlargement of the automatic pickling system of the present invention. Figure 2 ;

[0050] Figure 4 This is a partial enlargement of the automatic pickling system of the present invention. Figure 3 ;

[0051] Figure 5 This is a schematic diagram of the workflow of the automatic pickling system of the present invention.

[0052] In the diagram, 1 is the water pump for the acid recovery tank, 2 is the water pump for the alkali recovery tank, 3 is the water pump for the clean water recovery tank, 4 is solenoid valve A for the acid recovery tank pipeline, 5 is solenoid valve B for the acid recovery tank pipeline, 6 is solenoid valve A for the alkali recovery tank pipeline, 7 is solenoid valve B for the alkali recovery tank pipeline, 8 is solenoid valve A for the clean water recovery tank pipeline, 9 is solenoid valve B for the clean water recovery tank pipeline, 10a is the first cylinder, 10b is the second cylinder, 11 is the lead screw motor, 12 is limit switch A, and 13 is the limit switch B. Position B, 14 is limit switch C, 15 is solenoid valve for wastewater neutralization tank, 16 is pH meter for wastewater neutralization tank, 17 is radar level gauge for acid recovery tank, 18 is ultrasonic level gauge for alkali recovery tank, 19 is ultrasonic level gauge for clean water recovery tank, 20 is water pump for acid storage tank, 21 is water pump for alkali storage tank, 22 is water pump for clean water storage tank, 23 is solenoid valve for acid storage tank pipeline, 24 is solenoid valve A for alkali storage tank pipeline, 25 is solenoid valve B for alkali storage tank pipeline, 26 is... Solenoid valves for the acid mist tower alkali replenishment pipeline, 27 is solenoid valve A for the clear water tank pipeline, 28 is solenoid valve B for the clear water tank pipeline, 29 is solenoid valve for the filter tower water replenishment pipeline, 30 is solenoid valve for the acid mist tower water replenishment pipeline, 31 is radar level gauge for the acid storage tank, 32 is ultrasonic level gauge for the alkali storage tank, 33 is ultrasonic level gauge for the clear water tank, 34 is solenoid valve for the filter tower water replenishment pipeline, 35 is solenoid valve for the acid mist tower wastewater discharge, 36 is solenoid valve for the filter tower wastewater discharge, and 37 is a discharge... The following are listed: 38 is the motor of the air blower; 39 is the ultrasonic level gauge of the filter tower; 40 is the ultrasonic level gauge of the acid mist tower; 41 is the pH meter of the acid mist tower; 42 is the acid washing tank; 43 is the acid recovery tank; 44 is the alkali recovery tank; 45 is the clean water recovery tank; 46 is the acid storage tank; 47 is the alkali storage tank; 48 is the clean water storage tank; 49 is the acid mist tower; 50 is the filter tower; 51 is the waste liquid neutralization tank; 52 is the sample; and 53 is the ultrasonic level gauge of the waste liquid neutralization tank. Detailed Implementation

[0053] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0054] (1) The technical solution of this patent sets three pickling methods according to the pickling time of the sample: rapid pickling, normal pickling, and long-term pickling.

[0055] These three pickling methods were mainly summarized from the original pickling operations.

[0056] First method, rapid pickling:

[0057] Rapid pickling is mainly for high-temperature sample pickling (steel plate coiling temperature ≥ 680 degrees). Since the higher the steel plate temperature, the more fully the acid reaction occurs, a long pickling time will cause over-pickling, resulting in inconsistencies between the hot-rolled pickling sample and the cold-rolled pickling result. In this technical solution, the rapid pickling time is set to 4 minutes and 30 seconds.

[0058] The second type, normal pickling:

[0059] Normal pickling is mainly for samples with a steel plate coiling temperature of ≤680 degrees Celsius, and the pickling time is set to 5 minutes.

[0060] The third method is long-term pickling:

[0061] Long-term pickling refers to pickling cold steel plates at room temperature. Because the temperature of the steel plate is low and the reaction rate of the acid is slow, the pickling time for such cold steel plates is set to 30 minutes in this technical solution.

[0062] The selection of pickling time can be divided into two types: automatic selection and manual selection.

[0063] The automatic selection process involves the L2 computer transmitting the coiling temperature of the steel coil to be pickled to this system, and the system automatically selecting the pickling time according to the preset pickling time conditions.

[0064] For cold-rolled steel sheets, since there is no relevant information on the temperature of the steel coils, the sample pickling operation is carried out by manually selecting the sample.

[0065] The pickling time settings mentioned above can be adjusted in a timely manner according to changes in the next process to meet the needs of users in the next process.

[0066] (2) Set the neutralization and cleaning times in the pickling operation to 1 minute each. The working pause time between the three media during the pickling operation is 25 seconds. The time for the water tray to move back and forth between position A, position B and position C is 5 seconds.

[0067] (3) By transmitting steel coil information through L2 (such as contract number starting with X representing pickled plates, contract number starting with N representing electro-galvanized plates, and combining the steel coil information with the steel tapping mark, sorting degree, and user information in the quality report), there are special prompt screens for some products with special pickling requirements.

[0068]

[0069]

[0070] (4) The system includes some past cases of oxide scale defects and the final judgment results of oxide scale defects after sample pickling for different users, which can be used as a reference for operators after pickling samples. It is especially helpful for operators who are new to quality work. In addition, some samples can be adjusted according to the current market acceptance of oxide scale defects.

[0071] (5) Workflow of this technical solution: The PLC receives position signals and pH values ​​transmitted from sensors and measuring instruments (limit A, limit B, limit C, 2 pH measuring instruments, 8 liquid level gauges, etc.) and liquid level information in each tank and tower. Through calculation, the PLC issues work instructions to the cylinder, screw motor, exhaust device motor, 7 water pumps, and 18 solenoid valves according to the set work program to complete a series of tasks such as acid washing, neutralization, acid and alkali preparation, liquid replenishment, and acid mist tower exhaust.

[0072] (6) The chemical equation for acid-base neutralization in this technical solution: HCl + NaOH = NaCl (sodium chloride) + H2O

[0073] (7) The pickling medium in this technical solution is a 14-16% HCl aqueous solution at room temperature, which is prepared by 33% HCl solution and water. The calculation formula for the preparation of the pickling medium is: c1V1=c2V2, which shows that the ratio of 33% HCl solution to water is 1:1.2, and a 15% HCl aqueous solution can be prepared.

[0074] The specific calculation formulas for the preparation of the alkaline washing medium are as follows:

[0075] Concentration before dilution c1 × Volume of solution before dilution V1 = Concentration after dilution c2 × Volume of solution after dilution V2

[0076] (8) The alkaline washing medium in this technical solution is a 4-6% NaOH aqueous solution at room temperature, which is prepared by 32% NaOH solution and water. The calculation formula for preparing the alkaline washing medium is: c1V1=c2V2. It is found that the ratio of 32% NaOH solution to water is 1:5.4, which can prepare a 5% NaOH aqueous solution.

[0077] The calculation formula for the preparation of the alkaline washing medium is the same as that described in (7).

[0078] (9) The wastewater neutralization ratio in this technical solution is calculated by using a series of chemical formulas (such as the dilution formula for solution concentration, the ion product constant formula, etc.) to determine the neutralization ratio of 15% HCl aqueous solution for acid washing medium and 5% NaOH aqueous solution for alkaline washing medium to be 1:2.61.

[0079] (10) The wastewater neutralization method of this technical solution adopts batch neutralization. The neutralization target value is calculated according to pH value 7.5. The maximum neutralization value is 70% of the water level limit of the wastewater neutralization tank. After neutralization, the pH meter will be tested. At this time, the actual pH value of neutralization will deviate from the calculated value. However, the target value of neutralization pH value is the middle value of pH value 6-9 that meets the discharge requirements. Therefore, as long as the deviation between the actual pH value of neutralization and the calculated value is within the specified range (pH value 6-9), the discharge requirements can be met and it can be discharged.

[0080] In actual process operation, this technical solution is implemented according to the following steps:

[0081] 1) After the PLC system receives the relevant information about the sample 52 to be pickled from L2, once the sample 52 enters the pickling tank 42, the computer system receives a signal and the PLC issues an instruction to activate the first cylinder 10a and the second cylinder 10b to close the cover. At the same time, it also issues an instruction to rotate the lead screw motor 11. After the computer system receives the limit A signal, the PLC issues the corresponding start time of the acid recovery tank water pump 1 according to the winding temperature (such as 4 minutes and 30 seconds or 5 minutes). When the acid recovery tank water pump 1 starts, the acid recovery tank pipeline solenoid valve A4 opens and the acid recovery tank pipeline solenoid valve B5 closes, so that the acid flows from the acid recovery tank 43 to the pickling tank 42 and then back to the acid recovery tank 43, making it a cycle.

[0082] 2) After pickling is completed, wait 25 seconds until all the acid solution flows into the acid recovery tank 43. Then, the PLC sends a command to rotate the lead screw motor 11. After the PLC system receives the signal from limit switch B13, it sends another command to start the water pump 2 of the alkali recovery tank (1 minute). At the same time, it also sends a signal to open the solenoid valve A6 of the alkali recovery tank pipeline and close the solenoid valve B7 of the alkali recovery tank pipeline, so that the alkali solution flows from the alkali recovery tank 44 to the pickling tank 42 and then back to the alkali recovery tank 44, making it a cycle.

[0083] 3) After neutralization, wait 25 seconds until all the alkaline solution flows into the alkaline solution recovery tank 44. The PLC sends a command to rotate the lead screw motor 11. After the PLC system receives the signal from limit switch C14, it sends another command to start the water pump 3 in the clean water recovery tank (1 minute). At the same time, it also sends a signal to open the solenoid valve A8 in the clean water recovery tank pipeline and close the solenoid valve B9 in the clean water recovery tank pipeline, so that the clean water flows from the clean water recovery tank 45 to the pickling tank 42 and then back to the clean water recovery tank 45, making it a cycle. The entire pickling operation is completed.

[0084] 4) After prolonged use, the acid and alkali solutions react with the sample, increasing the amount of iron ions in the acid solution and reducing its pickling effect. Therefore, the acid and alkali solutions must be replaced. The waste acid solution in acid recovery tank 43, the waste alkali solution in alkali recovery tank 44, and the wastewater in clean water recovery tank 45 are discharged into waste liquid neutralization tank 51 for neutralization. The PLC system calculates the neutralization process based on the liquid level displayed by the ultrasonic level gauge 53 in waste liquid neutralization tank 51, and then adjusts the neutralization solution according to the required concentration of 15% HCl aqueous solution for pickling and 5% NaOH aqueous solution for alkali. The ratio is 1:2.61. Combined with the level displays from the radar level gauge 17 of the acid recovery tank 43, the ultrasonic level gauge 18 of the alkali recovery tank 44, and the ultrasonic level gauge 19 of the clean water recovery tank 45, the system calculates how much the liquid level in each of the three recovery tanks should be lowered to achieve the neutralization target of 7.5 without exceeding the remaining volume V of the waste liquid neutralization tank. After calculating the results, the PLC system activates the acid recovery tank pump 1, the alkali recovery tank pump 2, and the clean water recovery tank pump 3. Simultaneously, the solenoid valve of the acid recovery tank pipeline is opened. B5, B7, and B9 of the alkali recovery tank pipeline are opened, and simultaneously, A4, A6, and A8 of the acid recovery tank pipeline are closed. When the liquid levels in the three recovery tanks are lower than the calculated remaining liquid level (the radar level gauge 17 of the acid recovery tank, the ultrasonic level gauge 18 of the alkali recovery tank, and the ultrasonic level gauge 19 of the clean water recovery tank will report the liquid level to the computer system), the ultrasonic level gauge 53 of the waste liquid neutralization tank will also report the liquid level when it reaches the waste liquid neutralization tank 51. When the volume reaches 70%, the system sends a feedback signal to the PLC system. The PLC system then shuts down the acid recovery tank pump 1, the alkali recovery tank pump 2, and the clean water recovery tank pump 3, waiting for the pH meter 16 in the wastewater neutralization tank to send the current pH value back to the PLC. If the pH is too acidic, the alkali recovery tank pump 2 is turned on; if the pH is too alkaline, the acid recovery tank pump 1 is turned on. If the pH value is within the range of 6-9, the PLC system will issue a command to open the solenoid valve 15 in the wastewater neutralization tank, discharging the wastewater into the wastewater pool. This process is repeated several times until all the wastewater in the three recovery tanks is neutralized.

[0085] Calculation formula:

[0086] V = A * B * C (length * width * height) * 70% - a * b * c (length * width * height);

[0087] Where A, B, and C are the length, width, and height dimensions of the waste liquid neutralization tank, a, b, and c are the length, width, and height dimensions corresponding to the remaining liquid level in the recovery tank, and V is the remaining volume of the waste liquid neutralization tank.

[0088] 5) During acid preparation, the PLC first obtains level information from the radar level gauge 17, ultrasonic level gauge 18, and ultrasonic level gauge 19 of the acid recovery tank 43, alkali recovery tank 44, and clean water recovery tank 45. Then, the acid and alkali media are prepared in ratios of 1:1.2 and 1:5.4 respectively, so that the concentration of the acid media reaches about 15% and the concentration of the alkali media reaches about 5%. The computer then calculates the amount to be prepared based on the relevant ratios, and the total amount prepared reaches about 90% of the tank volume. Finally, the PLC issues commands to start the acid storage tank pump 20, alkali storage tank pump 21, clean water tank pump 22, and the solenoid valves 23 and 25 of the acid storage tank pipeline and B and B of the alkali storage tank pipeline respectively. 28. Close the solenoid valves of the alkali storage tank pipeline A24, alkali replenishment pipeline 26, clear water storage tank pipeline A27, water replenishment pipeline 29, and alkali mist tower water replenishment pipeline 30. The liquid level information of the acid recovery tank 43 and alkali recovery tank 44 is fed back to the PLC via the radar level gauge 17 and ultrasonic level gauge 18. When the calculated liquid level has been reached, the PLC will issue a switching solenoid valve command to replenish water to dilute the concentration in the acid recovery tank 43 and alkali recovery tank 44 and shut down the acid storage tank water pump 20 and alkali storage tank water pump 21. After the liquid level fed back by the radar level gauge 17, ultrasonic level gauge 18, and ultrasonic level gauge 19 of the clear water recovery tank reaches the calculated level, the water replenishment system is shut down, and the acid preparation operation is completed.

[0089] 6) When the acid mist tower 49 and the filter tower 50 are working normally, the exhaust fan motor 37 and the acid mist tower spray pump 38 are in the open state, while the acid mist tower water supply pipeline solenoid valve 30, the acid mist tower alkali supply pipeline solenoid valve 26, the filter tower water supply pipeline solenoid valve 34, the acid mist tower wastewater discharge solenoid valve 35, and the filter tower wastewater discharge solenoid valve 36 are in the closed state. The filter tower ultrasonic level gauge 39, the acid mist tower ultrasonic level gauge 40, and the acid mist tower pH meter 41 will monitor the liquid level and pH of the acid mist tower 49 and the filter tower 50 in real time. When the liquid level is low, the PLC will issue a water replenishment command, and the water pump 22 in the clear water tank will open the relevant solenoid valve 30 for the acid mist tower water replenishment pipeline, or the solenoid valve 34 for the filter tower water replenishment pipeline will also open. When the liquid level reaches the preset value, the PLC will issue a command to close the water pump 22 in the clear water tank, the solenoid valve 30 for the acid mist tower water replenishment pipeline, and the solenoid valve 34 for the filter tower water replenishment pipeline. When the pH detector 41 of the acid mist tower detects that the pH value of the acid mist tower 49 exceeds the specified value, the PLC will issue a command to briefly and continuously open the water pump 21 in the alkali storage tank and the solenoid valve for the alkali replenishment pipeline of the acid mist tower. The system is set to shut down for 1 minute after each 10-second start-up. Once the pH meter 41 detects that the pH value of the acid mist tower 49 is within the specified range, the PLC will issue a command to shut down the water pump 21 in the alkali storage tank and the solenoid valve of the alkali replenishment pipeline in the acid mist tower. When the media in the acid mist tower 49 and the filter tower 50 reach the upper limit of their service life, the PLC will issue a command to open the wastewater discharge solenoid valve 35 in the acid mist tower and the wastewater discharge solenoid valve 36 in the filter tower. After the media in the acid mist tower 49 and the filter tower 50 are discharged into the waste liquid neutralization tank 51, the water replenishment operation will be repeated.

[0090] 7) For new employees, this PLC also serves as a guide and reference. The actual pickled sample 52 can be compared with the pickling sample judgment sample in the PLC, which can prevent misjudgment of the quality of the pickling sample. In addition, this PLC can also update the pickling sample judgment sample in a timely manner according to new quality standards to adapt to changes in quality.

[0091] exist Figure 2The automatic sample pickling device shown mainly includes a pickling tank with three functions: pickling, neutralization, and cleaning. The pickling tank consists of a tank body, cover plate, cylinder, guide plate, acid outlet pipe, alkali outlet pipe, clean water outlet pipe, waste liquid outlet pipe, and exhaust pipe. The sample is cleaned in the pickling tank by switching between different liquid media to complete the three operations: pickling, neutralization, and cleaning. Below the pickling tank is a movable liquid recovery and switching system, which consists of a water receiving tray, track, track wheels, limit switches, lead screw, lead screw sleeve, slide rail, motor, gears, drain pipe, and push-pull rod. The system moves back and forth between limit positions A, B, and C via the drain pipe of the water receiving tray. This invention enables the flow of different liquids into three corresponding tanks. Below the recycling and switching system is a liquid recycling system, which consists of three tanks for holding acid, alkali, and water, along with a radar level gauge, an ultrasonic level gauge, pipes, an acid- and alkali-resistant water pump, and a solenoid valve. The acid- and alkali-resistant water pumps pump the different media from the three tanks sequentially and at set times through pipes into the pickling tank for pickling, neutralization, and cleaning of the samples. The invention also includes a waste liquid neutralization tank, consisting of a tank, a pH meter, an ultrasonic level gauge, and pipes, which automatically neutralizes and discharges waste liquid, ensuring operator safety during pickling and acid replacement operations.

[0092] Specifically, the automatic sample pickling device includes a U-shaped box bracket; a pickling box is installed on the U-shaped box bracket;

[0093] An openable and closable pickling tank cover is installed on the top of the pickling tank;

[0094] Inside the pickling tank, there are at least one set of acid solution pipes, alkali solution pipes, and clean water pipes, respectively.

[0095] Two baffles are installed below the acid, alkali, and clean water pipes; one side of each baffle is connected to the inner wall of the pickling tank.

[0096] A downward drain pipe is installed at the bottom of the pickling tank to drain the liquid inside the pickling tank.

[0097] Below the pickling tank, there is a movable water receiving tray, and below the water receiving tray, there is a waste liquid outlet pipe.

[0098] Two sets of track wheels are symmetrically arranged below the water receiving tray, and tracks are respectively arranged below the two sets of track wheels to enable the water receiving tray to move horizontally along the tracks.

[0099] The water receiving tray moves under the drive of the drive motor, thereby pushing or pulling the water receiving tray along the track;

[0100] Below the waste liquid outlet pipe of the water receiving tray, an acid recovery tank, an alkali recovery tank, and a clean water recovery tank are installed in sequence; above the acid recovery tank, alkali recovery tank, and clean water recovery tank, respectively, an acid recovery tank recovery pipe, an alkali recovery tank recovery pipe, and a clean water recovery tank recovery pipe are installed respectively, and the recovery pipes of the three liquid recovery tanks and the waste liquid outlet pipe of the water receiving tray are on the same axis.

[0101] A limit stop is installed on the side of the water receiving tray;

[0102] Limit switches A12, B13, and C14 are set. These three limit switches (actually water tray position detection switches) are respectively set to correspond to the positions of the acid recovery tank recovery pipe, the alkali recovery tank recovery pipe, and the clean water recovery tank recovery pipe. Through the coordination of the limit baffles with the positions of the three limit switches and circuit control, the movement position of the water tray during the movement process can be positioned.

[0103] A radar level gauge is installed at the top of the acid recovery tank, and an ultrasonic level gauge is installed at the top of the alkali recovery tank and the clean water recovery tank respectively, so as to display the liquid level in the three liquid recovery tanks.

[0104] On the lower side of each of the three liquid recovery tanks, a connecting pipe is installed, and an acid and alkali resistant water pump is installed on each connecting pipe.

[0105] The outlet pipe of the acid and alkali resistant water pump is divided into two lines: the first line leads to the pickling tank and the second line leads to the waste liquid neutralization tank; a solenoid valve is installed on the first line and the second line respectively.

[0106] The automatic sample pickling device is also equipped with a liquid recovery switching system (a reciprocating water receiving tray and related limit switches: limit A, limit B and limit C).

[0107] For details regarding the specific structure and working process of the automatic sample pickling device in this technical solution, please refer to the relevant content in the invention patent application "Automatic Sample Pickling Device" filed by the applicant on the same day, which will not be described here.

[0108] Since the various figures in this specification adopt the drawing and labeling mode that conforms to the national standard, those skilled in the art can understand the structure represented in each figure and the corresponding component without any objection, so they will not be described one by one here.

[0109] The technical solution of this invention integrates sample pickling, waste liquid neutralization, acid preparation, and acid mist scrubbing tower discharge into a single automated operating system via a PLC. By setting, calculating, and controlling within the PLC, the workflow is optimized to ensure the quality of sample pickling and the safety of the operation. After receiving steel coil information from the pickling sample from the upper-level computer L2, the PLC selects the pickling time according to the pre-set program and parameters, and automatically pickles the sample. During the pickling process, detection devices such as limit switches, ultrasonic level gauges, radar level gauges, and pH meters provide the PLC with data on location, liquid level, and pH measurement values. The PLC then calculates and issues commands to start or stop motors, acid and alkali resistant water pumps, pipeline solenoid valves, air pumps, and other equipment according to the program to complete the sample pickling, waste liquid neutralization, acid preparation, and acid mist scrubbing tower discharge operations.

[0110] The technical solution of this invention completes the three operations of pickling, neutralization, and cleaning by switching between different liquid media. At the same time, a liquid recycling and switching system that can move back and forth can recycle the different liquids separately. Waste liquid can be automatically neutralized and discharged, which improves the efficiency of pickling operations, reduces the intensity of operations, and ensures the personal safety and operational safety of operators in pickling and acid replacement operations.

[0111] This invention can be widely used in the pickling process of cold-rolled substrates in hot rolling production.

Claims

1. An automatic sample plate pickling system control method, comprising setting a pickling tank with pickling, neutralizing and cleaning functions, the upper part of the pickling tank being provided with a cover plate that can be opened and closed; the pickling sample plate in the pickling tank is subjected to three liquid cleaning through switching to flow different liquid media, to complete the three operations of pickling, neutralizing and cleaning; a liquid recovery switching system and a corresponding liquid recovery system are arranged below the pickling tank; the corresponding liquid recovery system comprises an acid liquid recovery tank, an alkali liquid recovery tank and a clean water recovery tank; corresponding to the acid liquid recovery tank, the alkali liquid recovery tank and the clean water recovery tank, an acid liquid supplement circuit, an alkali liquid supplement circuit and a clean water supplement circuit are respectively arranged, the supplement circuit at least comprising a corresponding delivery pump and a pipeline solenoid valve arranged at the outlet of the delivery pump; the pickling tank is further connected with an acid mist tower pipeline; characterized in that: a liquid level detection device is arranged in each of the acid liquid recovery tank and the alkali liquid recovery tank; a position detection device of a water receiving tray is arranged in the liquid recovery switching system; a wastewater neutralizing tank is arranged at the outlet end of the acid liquid recovery tank and the alkali liquid recovery tank; a pH meter is arranged in the wastewater neutralizing tank; a PLC is arranged for receiving position signals, pH values and liquid level information in each tank and tower body transmitted from the position detection device, the pH meter and the liquid level detection device; after receiving the information of the steel coil of the pickling sample plate from a superior computer L2, the PLC selects a pickling time according to the set program and parameters to automatically pickling the sample plate; during the pickling process, the position information, liquid level and pH measurement value data are provided to the PLC by the arranged detection devices, the PLC calculates and sends instructions to open or close the motor, acid and alkali resistant water pump, pipeline solenoid valve and air pump equipment to complete the sample plate pickling operation, waste liquid neutralizing operation, acid preparation operation and acid mist tower discharge operation; the sample plate pickling operation, waste liquid neutralizing operation, acid preparation operation and acid mist tower discharge operation are integrated into an automatic operation system by the PLC, and the operation process is optimized by setting, calculating and controlling in the PLC; the automatic sample plate pickling system control method works according to the following steps: 1) after receiving the information of the pickling sample plate from the production process control computer L2, the PLC sends instructions to close the cover plate by the action of the first and second air cylinders, and sends instructions to rotate the screw motor, and after receiving the limit A signal, the PLC sends instructions to open the pump of the acid liquid recovery tank water pump according to the coiling temperature, the acid liquid recovery tank pipeline solenoid valve A is opened and the acid liquid recovery tank pipeline solenoid valve B is closed when the acid liquid recovery tank water pump is opened, so that the acid liquid flows from the acid liquid recovery tank to the pickling tank and then flows back to the acid liquid recovery tank, forming a cycle. ​ ​ ​ ​ ​ ​ ​ ​ 2) After the acid washing is finished, when all the acid flows into the acid recovery tank, the PLC sends a command to rotate the screw motor. When the PLC system receives the signal of limit B, it sends a command to open the water pump of the alkali recovery tank, and also sends a signal to open the pipeline electromagnetic valve A of the alkali recovery tank and close the pipeline electromagnetic valve B of the alkali recovery tank, so that the alkali flows from the alkali recovery tank to the acid washing tank and then back to the alkali recovery tank, forming a cycle; 3) After the neutralization is finished, when all the alkali flows into the alkali recovery tank, the PLC sends a command to rotate the screw motor. When the PLC system receives the signal of limit C, it sends a command to open the water pump of the clean water recovery tank, and also sends a signal to open the pipeline electromagnetic valve A of the clean water recovery tank and close the pipeline electromagnetic valve B of the clean water recovery tank, so that the clean water flows from the clean water recovery tank to the acid washing tank and then back to the clean water recovery tank, forming a cycle, and the whole acid washing operation is completed; 4) The PLC system calculates the liquid level displayed by the ultrasonic liquid level meter of the waste liquid neutralization tank, and according to the neutralization ratio of the acid washing medium and the alkali washing medium, combined with the liquid level displayed by the radar liquid level meter of the acid recovery tank, the ultrasonic liquid level meter of the alkali recovery tank, and the ultrasonic liquid level meter of the clean water recovery tank, it calculates how much the liquid level of each recovery tank should be lowered. After calculating the result, the PLC system opens the water pumps of the acid recovery tank, the alkali recovery tank, and the clean water recovery tank; at the same time, it opens the pipeline electromagnetic valves B of the acid recovery tank, the alkali recovery tank, and the clean water recovery tank, and closes the pipeline electromagnetic valves A of the acid recovery tank, the alkali recovery tank, and the clean water recovery tank; When the liquid levels of the three recovery tanks have been lowered to below the calculated remaining liquid height, the ultrasonic liquid level meter of the waste liquid neutralization tank feeds back to the PLC system when the liquid level reaches 70% of the volume of the waste liquid neutralization tank. The PLC system sends a command to close the water pumps of the acid recovery tank, the alkali recovery tank, and the clean water recovery tank, and waits for the pH detector of the waste liquid neutralization tank to feed back the current pH value to the PLC; If the pH value of the waste liquid neutralization tank is too acidic, the water pump of the alkali recovery tank is opened; If the pH value of the waste liquid neutralization tank is too alkaline, the water pump of the acid recovery tank is opened; If the pH value of the waste liquid neutralization tank is within the range of 6-9, the PLC sends a command to open the electromagnetic valve of the waste water neutralization tank, and the sewage is discharged into the sewage pool. The operation is repeated for several times until the waste water in the three recovery tanks is completely neutralized. 5) In the acid mixing operation, PLC first obtains liquid level related information from the acid liquid recovery tank, the alkali liquid recovery tank, the acid liquid recovery tank radar liquid level meter, the alkali liquid recovery tank ultrasonic liquid level meter and the clean water recovery tank ultrasonic liquid level meter, and then the acid medium and the alkali medium are mixed in a ratio of 1:1.2 and 1:5.4 respectively, so that the concentration of the acid medium reaches about 15% and the concentration of the alkali medium reaches about 5%, and the total amount of the mixed medium reaches about 90% of the volume of the acid liquid recovery tank or the alkali liquid recovery tank. Finally, PLC issues a command to open the acid liquid storage tank water pump, the alkali liquid storage tank water pump, the clean water storage tank water pump and the acid liquid storage tank pipeline electromagnetic valve, the alkali liquid storage tank pipeline electromagnetic valve B, the clean water storage tank pipeline electromagnetic valve B, and to close the alkali liquid storage tank pipeline electromagnetic valve A, the acid mist tower alkali supplement pipeline electromagnetic valve, the clean water storage tank pipeline electromagnetic valve A, the filter tower water supplement pipeline electromagnetic valve and the acid mist tower water supplement pipeline electromagnetic valve. The liquid level information is fed back to PLC through the acid liquid recovery tank radar liquid level meter and the alkali liquid recovery tank ultrasonic liquid level meter. When the liquid level reaches the calculated level, PLC issues a switching electromagnetic valve command to supplement water to the acid liquid recovery tank and the alkali liquid recovery tank, dilute the concentration, and close the acid liquid storage tank water pump and the alkali liquid storage tank water pump. When the liquid level fed back by the acid liquid recovery tank radar liquid level meter, the alkali liquid recovery tank ultrasonic liquid level meter and the clean water recovery tank ultrasonic liquid level meter reaches the calculated liquid level, the water supplement system is closed and the acid mixing operation is completed. 6) When the acid mist tower and the filter tower are working normally, the exhaust device motor and the acid mist tower spray pump are in an open state, and the acid mist tower water supplement pipeline electromagnetic valve, the acid mist tower alkali supplement pipeline electromagnetic valve, the filter tower water supplement pipeline electromagnetic valve, the acid mist tower waste water discharge electromagnetic valve and the filter tower waste water discharge electromagnetic valve are in a closed state. The filter tower ultrasonic liquid level meter, the acid mist tower ultrasonic liquid level meter and the acid mist tower pH detector monitor the liquid level and pH of the acid mist tower and the filter tower in real time. When the liquid level is low, PLC issues a water supplement command, and the clean water storage tank water pump opens the relevant acid mist tower water supplement pipeline electromagnetic valve or the filter tower water supplement pipeline electromagnetic valve. When the liquid level reaches the preset value, PLC issues a command to close the clean water storage tank water pump, the acid mist tower water supplement pipeline electromagnetic valve and the filter tower water supplement pipeline electromagnetic valve. When the acid mist tower pH detector detects that the pH value of the acid mist tower exceeds the specified value, PLC issues a short-term and continuous command to open the alkali liquid storage tank water pump and the acid mist tower alkali supplement pipeline electromagnetic valve. Each time the pump is opened for 10 seconds and then stopped for 1 minute. When the acid mist tower pH detector detects that the pH value of the acid mist tower is within the specified range, PLC issues a command to close the alkali liquid storage tank water pump and the acid mist tower alkali supplement pipeline electromagnetic valve. When the medium in the acid mist tower and the filter tower reaches the upper limit of the use period, PLC issues a command to open the acid mist tower waste water discharge electromagnetic valve and the filter tower waste water discharge electromagnetic valve. After the medium in the acid mist tower and the filter tower is discharged into the waste liquid tank, the water supplement operation is restarted.

2. The automatic gauge block etching system control method of claim 1, wherein The sample pickling operation includes rapid pickling, normal pickling and long-time pickling.

3. The automatic gauge block etching system control method of claim 2, wherein The selection of the pickling time in the fast pickling, normal pickling and long-time pickling modes can be realized by automatic selection and manual selection modes.

4. The automatic gauge block etching system control method of claim 1, wherein The batch neutralization mode is adopted in the wastewater neutralization, and the target value is calculated according to the pH value of 7.5, and the maximum value of the neutralization is 70% of the water level limit of the wastewater neutralization tank.

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