Control method of overflow washing water recovery system of plastic chromium plating roughening washing water tank

Abstract

This invention relates to a control method for an overflow wash water recovery system in a plastic electroplating chromium roughening wash tank. The method includes: (1) powering on the system; (2) detecting data from a first high / low level sensor; (3) detecting data from a third and second pressure gauge; (4) detecting data from the first pressure gauge; (5) detecting data from the second high / low level sensor; (6) detecting pressure data from the reverse osmosis unit; (7) operating the reverse osmosis recovery system; (8) detecting data from a fourth high / low level sensor; (9) operating the concentrate recovery system; (10) detecting data from the fourth high / low level sensor; and (11) storing the recycled water produced by the system in a recycled water collection tank.

Description

Technical Field

[0001] This invention belongs to the field of electroplating wastewater treatment technology, and specifically relates to a control method for an overflow washing water recovery system of a roughening washing tank for plastic electroplating chromium. Background Technology

[0002] Chromic anhydride and sulfuric acid are commonly used in various plastic and metal chromium electroplating processes. Plastic electroplating is primarily used for surface treatment of plastic products, improving their appearance, wear resistance, and corrosion resistance. Plastic electroplating technology is widely used in automotive parts, home appliances, and digital products, making wastewater recycling in the plastic electroplating industry a promising market opportunity. The roughening process in plastic electroplating mainly uses chromic anhydride (400–430 g / L) and sulfuric acid (380–420 g / L) to corrode the plastic parts. After passing through the roughening tank, the parts enter a recycling tank and a water-stopping tank for cleaning, followed by further cleaning in a stepped overflow cleaning tank. The overflow cleaning process requires continuous spray cleaning, and the cleaning tank needs to be equipped with overflow outlets, resulting in a large amount of cleaning water overflowing during production. Once the concentration in the reuse tank reaches a certain level, the water is directly returned to the roughening tank for reuse. The water-stopping tank then enters the chromic acid reuse process before returning to the roughening tank. The overflow washing tank generates overflow water with varying concentrations. This overflow water mainly contains chromic anhydride and sulfuric acid, as well as small amounts of trivalent chromium and organic matter. However, the chromium content in the overflow water does not reach the concentration required for the reuse process. Because a large amount of overflow water is discharged, failure to recycle it would result in water waste and increase the treatment burden on the water station. Therefore, using an overflow washing water recycling system to recover water and chromic acid resources is crucial. Ordinary recycling devices lack automatic control systems, requiring significant manpower for real-time monitoring. Furthermore, considerable time is needed to learn the various operating procedures before operation, and accidents are prone to occur due to negligence. This leads to a large initial investment of human resources and the potential for unforeseen human error causing accidents, resulting in substantial sunk costs. Summary of the Invention

[0003] The purpose of this invention is to provide a 24 / 7 automatic monitoring and control system for a recycling device. This system uses various sensors to automatically monitor data from each component in real time, performs system-wide detection, and executes corresponding operations according to a pre-set program. This allows for unattended, 24 / 7 operation with extremely low machine learning costs, enabling rapid learning and automatic operation without the need for dedicated personnel. The recycling device with this 24 / 7 automatic monitoring and control system significantly reduces operating costs, ensuring maximum profitability, and minimizes safety hazards caused by human error in the control method for the overflow wash water recycling system of a plastic electroplating chromium roughening washing tank. Another purpose of this invention is to provide a 24 / 7 automatic control system that automatically identifies and collects the first-generation membrane concentrate. Once sufficient production is detected, the system automatically activates a secondary membrane concentrate recycling system to reuse this wastewater, further reducing water waste and increasing the benefits of recycled water in the control method for the overflow wash water recycling system of a plastic electroplating chromium roughening washing tank.

[0004] The technical solution of this invention is a control method for the overflow wash water recovery system of the plastic electroplating chromium roughening wash tank. Its special feature is that the overflow wash water recovery system of the plastic electroplating chromium roughening wash tank includes, in sequence, a cleaning and transfer device, a filtration device, a reverse osmosis device, a reverse osmosis membrane cleaning device, a collection device, and an activated carbon cleaning device; the control method includes the following steps:

[0005] (1) System power-on startup;

[0006] (2) Detect the data from the first high and low liquid level sensor;

[0007] (2.1) Determine whether the liquid level is higher than the high level. If yes, open the first control valve, close the second control valve, and return to step (2); if no, close the first control valve, open the second control valve, and return to step (2).

[0008] (2.2) Determine if the liquid level is below the low level. If yes, close the third control valve, turn on the centrifugal pump, and wait 15 minutes before returning to step (2). If no, proceed to the next step (3).

[0009] (3) Detect the data from the third and second pressure gauges;

[0010] (4) Check the data from the first pressure gauge;

[0011] (4.1) Determine if the pressure exceeds the limit. If so, open the desorption circulation pump, the fourteenth control valve, the fifth control valve, and close the third control valve and the centrifugal pump. After the activated carbon circulation desorption system has been working for 30 minutes, return to step (4). If not, open the centrifugal pump, the third control valve, the fourth control valve, and the seventh control valve.

[0012] (5) Detect data from the second high and low liquid level sensor;

[0013] (5.1) Determine whether the liquid level is higher than the high level. If yes, close the sixteenth control valve, open the second normal valve, and return to step (5); if no, close the second normal valve, open the sixteenth control valve, and return to step (5).

[0014] (5.2) Determine if the liquid level is below the low level. If yes, shut down the reverse osmosis pressure pump and the eighth control valve, and wait 20 minutes before returning to step (5). If no, proceed to the next step (6).

[0015] (6) Detect the pressure data of the reverse osmosis unit;

[0016] (6.1) Determine if the pressure exceeds the limit. If so, close the reverse osmosis pressure pump, the third ordinary valve, the thirteenth control valve, and the eighth control valve, and open the cleaning circulation pump, the seventeenth control valve, and the ninth control valve. The reverse osmosis membrane circulation cleaning system will work for 30 minutes and then return to step (6). If not, close the cleaning circulation pump, the seventeenth control valve, and the ninth control valve, and open the reverse osmosis pressure pump, the third ordinary valve, the thirteenth control valve, and the eighth control valve.

[0017] (7) Operate the reverse osmosis recovery system;

[0018] (8) Detect the data from the fourth high and low liquid level sensor;

[0019] (8.1) Determine if the liquid level is higher than the high level. If not, return to the running step (7); if so, close the sixth control valve and the thirteenth control valve, open the twelfth control valve and the tenth control valve, and proceed to the next step (9).

[0020] (9) Operate the concentrate recovery system;

[0021] (10) Detect the data from the fourth high and low liquid level sensor;

[0022] (10.1) Determine if the liquid level is below the low level. If not, return to step (9); if so, close the twelfth and tenth control valves, open the sixth and thirteenth control valves, and return to step (6).

[0023] 11. The recycled water produced by the system will be stored in recycled water collection buckets.

[0024] Preferably, the circulating desorption solution in the activated carbon circulating desorption system in step (4.1) is an aqueous solution containing sodium hypochlorite and sodium hydroxide, with the sodium hypochlorite concentration being 1-3% and the sodium hydroxide concentration being 3-5%.

[0025] Preferably, the circulating cleaning fluid in the reverse osmosis membrane circulating cleaning system in step (6.1) is an aqueous solution containing sodium hypochlorite and sodium hydroxide, with a sodium hypochlorite concentration of 1-3% and a sodium hydroxide concentration of 5-7%, and 0.0001-0.0006% scale inhibitor is added.

[0026] Preferably, the cleaning device and transfer device include interconnected primary overflow cleaning tank, secondary overflow cleaning tank, tertiary overflow cleaning tank, and overflow water transfer tank, used for spray washing of the plated parts and collection of overflow water for reuse. The pipeline connecting the inlet of the tertiary overflow cleaning tank and the overflow water transfer tank is equipped with a second control valve and a bypass pipeline first control valve. The overflow water transfer tank is equipped with a first high and low liquid level sensor. The pipeline connected to the primary bag filter of the filtration device is equipped with a first ordinary valve, a centrifugal pump, a check valve, and a third control valve. When the liquid level is detected to be higher than the high level, the first control valve is opened and the second control valve is closed. When the liquid level is detected to be lower than the low level, an alarm is triggered and the third control valve and the centrifugal pump are closed.

[0027] Preferably, the filtration device comprises a primary bag filter, a secondary activated carbon filter, a tertiary bag filter, and a wastewater storage tank connected in sequence, for removing organic matter, impurities, and storing pretreated overflow wash water; the primary bag filter is equipped with a third pressure gauge, the secondary activated carbon filter with a first pressure gauge, and the tertiary bag filter with a second pressure gauge; a seventh control valve is installed on the connecting pipeline between the primary bag filter and the secondary activated carbon filter, and a fourth control valve is installed on the connecting pipeline between the secondary activated carbon filter and the tertiary bag filter; the outlet of the tertiary bag filter is connected to the wastewater storage tank. The wastewater storage tank is equipped with a second ordinary valve on its connecting pipeline; the wastewater storage tank is equipped with a second high and low liquid level sensor; the overflow water passes through a first-stage bag filter, a second-stage activated carbon filter and a third-stage bag filter in sequence before entering the wastewater storage tank. When the pressure values ​​of the third pressure gauge and the second pressure gauge exceed 0.5 MPa, the consumables are replaced. When the pressure value of the pressure gauge exceeds 1 MPa, the cleaning system of the activated carbon filter is started. When the liquid level in the wastewater storage tank reaches the high liquid level under the detection of the high and low liquid level sensor, an alarm is issued and the third control valve is closed. When the liquid level reaches the low liquid level, the eighth control valve and the reverse osmosis pressure pump are closed.

[0028] Preferably, the reverse osmosis device includes a reverse osmosis pressure pump and a reverse osmosis membrane unit; the inlet of the reverse osmosis pressure pump is connected to the outlet at the bottom of the wastewater storage tank and a sixth control valve is installed on the connecting pipe; the outlet of the reverse osmosis pressure pump is connected to the inlet of the reverse osmosis membrane unit and a first check valve and a seventh control valve are installed on the connecting pipe; the top inlet is connected to the cleaning agent outlet of the reverse osmosis membrane unit; the outlet pipe is equipped with a fifth ordinary valve and a ninth control valve; the reverse osmosis membrane unit is equipped with a reverse osmosis membrane; an integrated automatic control system and a display panel are provided on one side to display the liquid level of each liquid level sensor and the pressure values ​​of each pressure gauge, as well as to automatically control the activated carbon filter cleaning device, the reverse osmosis membrane cleaning device, and the concentrated water secondary reuse program, and there are manual control buttons.

[0029] Preferably, the collection device includes a concentrate collection tank and a recycled water collection tank; the top inlet of the recycled water collection tank is connected to the recycled water outlet of the reverse osmosis unit, and a third ordinary valve is installed on the connecting pipe; a fifth high-level sensor is installed inside the recycled water collection tank, and the sensed water level value is displayed on the reverse osmosis unit control panel; a fourth high-low level sensor is installed inside the concentrate collection tank, the top inlet is connected to the concentrate outlet of the reverse osmosis membrane unit, and a fourth ordinary valve, a tenth control valve, and a thirteenth control valve are installed on the connecting pipe; the bottom outlet is connected to the inlet of the reverse osmosis pressure pump, and the connecting pipe is configured with... There is a seventh ordinary valve and a twelfth control valve. When the liquid level in the concentrate collection tank reaches the high level under the detection of the fourth high, medium and low liquid level sensor, the tenth control valve is opened, the thirteenth control valve is closed, the twelfth control valve is opened, and the sixth control valve is closed, switching to the concentrate reuse program. When the liquid level in the concentrate collection tank is lower than the low level under the detection of the fourth high, medium and low liquid level sensor, the seventeenth control valve is opened, the tenth control valve is closed, the sixth control valve is opened, and the twelfth control valve is closed, switching to the overflow wastewater reuse program. The outlet of the pipeline where the tenth control valve is located is connected to the chromic acid reuse system.

[0030] Preferably, the activated carbon filter cleaning device includes a desorption circulation pump and an activated carbon cleaning agent storage tank. The inlet of the desorption circulation pump is connected to the outlet at the bottom of the activated carbon cleaning agent storage tank, and an eighth ordinary valve is installed on the connecting pipeline. The outlet of the desorption circulation pump is connected to the cleaning agent inlet at the top of the activated carbon filter, and a third check valve and a fourteenth control valve are installed on the connecting pipeline. A sixth high-level liquid level sensor is installed in the activated carbon cleaning agent storage tank. When the liquid level is detected to be below the middle level, an alarm is triggered and the fourteenth control valve and the desorption circulation pump are closed. When the pressure gauge reading is higher than 1 MPa, an alarm is triggered by the reverse osmosis membrane main unit control panel to start the activated carbon cleaning program, close the third control valve, the centrifugal pump, the third control valve, and the fourth control valve, and open the fourteenth control valve and the fifth control valve to begin circulating desorption until the pressure gauge reading is lower than 0.5 MPa.

[0031] Preferably, the control valves installed in each pipeline are all solenoid valves, which are electrically connected to the PLC control circuit, and the ordinary valves installed are all ball valves.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) This invention incorporates an automatic control system into the recycling device. This automatic control system, through the installation of various sensors, automatically monitors data from each component in real time and performs system-wide detection. It executes corresponding operations according to a pre-set program, achieving unattended, 24 / 7 operation. Furthermore, the machine learning cost is extremely low, allowing it to quickly learn operation without the need for dedicated personnel. The recycling device with the 24 / 7 automatic monitoring and control system not only significantly reduces operating costs to ensure maximum profitability but also minimizes safety accidents caused by human error. Compared to ordinary recycling processes, the 24 / 7 automatic control system can also identify and collect the initial membrane concentrate. Once sufficient production is detected, it automatically activates a secondary membrane concentrate recycling system to reuse this wastewater, further reducing water waste and increasing the benefits of recycled water.

[0034] (2) The overflow washing water described in this invention undergoes preliminary purification through a three-stage filter, which can initially remove organic matter and suspended solids from the wastewater. Then, it passes through a reverse osmosis device for metal ion separation and further removal of other soluble impurities. The concentrated water generated from the overflow water treated by the reverse osmosis device is collected and then subjected to osmosis recovery again. The concentrated water generated in the second process is then fed into a chromic acid recycling process for chromic acid recovery. The ion removal rate of the recycled water in this invention can reach 98.5% to 99.5%. Combined with the chromic acid recycling process, the chromium resource recovery rate is 95% to 98%, and the overall water production rate can reach 75% to 80%, which can minimize resource waste.

[0035] (3) The concentrated water generated from the overflow water treated by the reverse osmosis device of the present invention is collected and then subjected to osmosis recovery again. The concentrated water generated in the second process is then fed into the chromic acid recycling process for chromic acid recovery.

[0036] (4) The ion removal rate of the recycled water of this invention can reach 98.5-99.5%, and the chromium resource recovery rate after combining with the chromic acid recycling process is 95-98%, and the comprehensive water production rate can reach 75-80%, which can minimize resource waste.

[0037] (5) The overflow washing water recycling system for plastic electroplating chromium roughening washing tank provided by the present invention can effectively remove impurities such as organic matter, suspended solids and metal ions from the overflow water, recycle useful water resources, reduce water usage costs, and improve the recovery rate by adopting a concentrated water secondary treatment method, thus achieving good social and economic benefits. Attached Figure Description

[0038] Figure 1This is a flowchart of the control method for the overflow wash water recovery system of the plastic electroplating chromium roughening wash tank of the present invention;

[0039] Figure 2 This is a schematic diagram of the overflow washing water recovery system of the plastic electroplating chromium roughening washing tank of the present invention.

[0040] Explanation of key component symbols:

[0041] Cleaning transfer unit 1 Primary overflow cleaning tank 11 Secondary overflow cleaning tank 12 Three-stage overflow cleaning tank 13 First control valve 131 Second control valve 132 Overflow water rotating bucket 14 First high and low liquid level sensor 141 Centrifugal pump 15 Third control valve 151 Check valve 152 First ordinary valve 153 Filter device 2 Secondary activated carbon filter 21 First pressure gauge 211 Fourth control valve 212 Fifth control valve 213 Three-stage bag filter 22 Second pressure gauge 221 Fifteenth control valve 222 Sixteenth control valve 223 Wastewater storage tank 23 Second high / low liquid level sensor 231 Sixth control valve 232 24-stage bag filter Third pressure gauge 241 Seventh control valve 242 Reverse osmosis device 3 Reverse osmosis pressure pump 31 First check valve 31 Eighth control valve 312 32 reverse osmosis membrane unit Third general valve 321 Fourth ordinary valve 322 Fifth ordinary valve 323 Ninth control valve 324 Tenth control valve 325 Seventeenth control valve 326 Reverse osmosis membrane 327 Display panel 328 Manual control button 329 Reverse osmosis membrane cleaning device 4 Reverse osmosis membrane cleaning agent storage tank 41 Third high and low liquid level sensor 411 Sixth ordinary valve 412 Cleaning circulation pump 42 Second check valve 421 Eleventh control valve 423 Collection device 5 Concentrate collection tank 51 Fourth high, medium and low liquid level sensor 511 Twelfth control valve 512 Seventh ordinary valve 513 Thirteenth control valve 514 52 recycled water collection buckets Fifth high, medium and low liquid level sensor 521 Activated carbon cleaning device 6 Activated carbon cleaning agent storage tank 61 611 High School Liquid Level Sensor Desorption circulation pump 62 Fourteenth control valve 621 Third check valve 622 Second general valve 623 Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings:

[0043] Please see Figure 1 As shown, the control method for the overflow wash water recovery system of the roughening wash tank in plastic electroplating chromium includes the following steps:

[0044] (1) System power-on startup;

[0045] (2) Detect the data from the first high and low liquid level sensor 141;

[0046] (2.1) Determine whether the liquid level is higher than the high level. If yes, open the first control valve 131, close the second control valve 132, and return to step (2); if no, close the first control valve 131, open the second control valve 132, and return to step (2).

[0047] (2.2) Determine if the liquid level is below the low level. If yes, close the third control valve 151, turn on the centrifugal pump 15, and wait 15 minutes before returning to step (2). If no, proceed to the next step (3).

[0048] (3) Detect the data from the third pressure gauge 241 and the second pressure gauge 221;

[0049] (4) Detect the data from the first pressure gauge 211;

[0050] (4.1) Determine if the pressure exceeds the limit. If so, open the desorption circulation pump 62, the fourteenth control valve 621, the fifth control valve 213 and close the third control valve 151 and the centrifugal pump 15. After the activated carbon circulation desorption system works for 30 minutes, return to step (4). If not, open the centrifugal pump 15, the third control valve 151, the fourth control valve 212 and the seventh control valve 242. The circulating desorption liquid in the activated carbon circulation desorption system is an aqueous solution containing sodium hypochlorite and sodium hydroxide. The concentration of sodium hypochlorite is 1-3% and the concentration of sodium hydroxide is 3-5%.

[0051] (5) Detect the data from the second high / low liquid level sensor 231;

[0052] (5.1) Determine whether the liquid level is higher than the high level. If yes, close the sixteenth control valve 223, open the second ordinary valve 222, and return to step (5); if no, close the second ordinary valve 222, open the sixteenth control valve 223, and return to step (5).

[0053] (5.2) Determine if the liquid level is below the low level. If yes, shut down the reverse osmosis pressure pump 31 and the eighth control valve 312, and wait 20 minutes before returning to step (5). If no, proceed to the next step (6).

[0054] (6) Detect the pressure data of the reverse osmosis unit 32;

[0055] (6.1) Determine if the pressure exceeds the limit. If so, close the reverse osmosis pressure pump 31, the third ordinary valve 321, the thirteenth control valve 514, and the eighth control valve 312, and open the cleaning circulation pump 42, the seventeenth control valve 326, and the ninth control valve 324. The reverse osmosis membrane circulation cleaning system operates for 30 minutes and then returns to step (6). If not, close the cleaning circulation pump 42, the seventeenth control valve 326, and the ninth control valve 324, and open the reverse osmosis pressure pump 31, the third ordinary valve 321, the thirteenth control valve 514, and the eighth control valve 312. The circulating cleaning liquid in the reverse osmosis membrane circulation cleaning system is an aqueous solution containing sodium hypochlorite and sodium hydroxide. The concentration of sodium hypochlorite is 1-3%, the concentration of sodium hydroxide is 5-7%, and 0.0001-0.0006% scale inhibitor is added.

[0056] (7) Operate the reverse osmosis recovery system;

[0057] (8) Detect the data from the fourth high / low liquid level sensor 511;

[0058] (8.1) Determine if the liquid level is higher than the high level. If not, return to the running step (7); if so, close the sixth control valve 232 and the thirteenth control valve 514, open the twelfth control valve 512 and the tenth control valve 325, and proceed to the next step (9).

[0059] (9) Operate the concentrate recovery system;

[0060] (10) Detect the data from the fourth high / low liquid level sensor 511;

[0061] (10.1) Determine if the liquid level is below the low level. If not, return to step (9); if so, close the twelfth control valve 512 and the tenth control valve 325, open the sixth control valve 232 and the thirteenth control valve 514, and return to step (6).

[0062] ⑪ The recycled water produced by the system will be stored in recycled water collection tank 52.

[0063] Please see Figure 2As shown, the overflow washing water recycling and treatment system for plastic electroplating chromium roughening washing tank includes a cleaning and transfer device 1, a filtration system 2, a reverse osmosis device 3, a reverse osmosis membrane cleaning device 4, a collection device 5, and an activated carbon cleaning device 6 connected in sequence.

[0064] The cleaning device and transfer device 1 include a primary overflow cleaning tank 11, a secondary overflow cleaning tank 12, a tertiary overflow cleaning tank 13, and an overflow water transfer tank 14, used for spray washing of the plated parts and collection of overflow water for reuse. The pipeline connecting the inlet of the tertiary overflow cleaning tank 13 and the overflow water transfer tank 14 is equipped with a second control valve 132 and a bypass pipeline first control valve 131. The overflow water transfer tank 14 is equipped with a first high and low liquid level sensor 141. The pipeline connected to the primary filter bag filter 24 is equipped with a first ordinary valve 153, a centrifugal pump 15, a check valve 152, and a third control 151. When the liquid level is detected to be higher than the high level, the first control valve 131 is opened and the second control valve 132 is closed. When the liquid level is detected to be lower than the low level, an alarm is triggered and the third control valve 151 and the centrifugal pump 15 are closed.

[0065] The filtration system 2 includes a three-stage filter and a wastewater storage device. The illustrated embodiment consists of a primary bag filter 24, a secondary activated carbon filter 21, a tertiary bag filter 22, and a wastewater storage tank 23. It is used to remove organic matter, impurities, and store pre-treated overflow wash water. The primary bag filter 24 is equipped with a third pressure gauge 241, the secondary activated carbon filter 21 with a first pressure gauge 211, and the tertiary bag filter 22 with a second pressure gauge 221. The three filters are connected in series, with a seventh control valve 242 and a seventh control valve 212 on the connecting pipes. The outlet of the tertiary bag filter 22 is connected to the wastewater storage tank 23, with a fifteenth control valve 222 and a sixteenth control valve 223 on the connecting pipes. A second high / low level sensor 231 is installed inside the wastewater storage tank. Overflow water sequentially passes through a primary bag filter 24, a secondary activated carbon filter 21, and a tertiary bag filter 22 before entering the wastewater storage tank 23. When the pressure values ​​of the third pressure gauge 241 and the second pressure gauge 221 exceed 0.5 MPa, the consumables are replaced. When the pressure value of the second pressure gauge 221 exceeds 1 MPa, the cleaning system of the activated carbon filter 21 is activated. When the liquid level in the wastewater storage tank 23 reaches the high level detected by the second high / low liquid level sensor 231, an alarm is sounded and the third control valve 151 is closed. When the liquid level reaches the low level, the eighth control valve 312 and the reverse osmosis pressure pump 31 are closed. The tertiary filter in the filtration system 2 is a security filter for the reverse osmosis device 3, mainly protecting the membrane and pump and intercepting particles larger than 1 μm.

[0066] Please see again. Figure 1The reverse osmosis device 3 and the reverse osmosis membrane cleaning device 4 include a reverse osmosis pressure pump 31, a reverse osmosis membrane main unit 32, a reverse osmosis membrane cleaning agent storage tank 41, and a cleaning circulation pump 42. The inlet of the reverse osmosis pressure pump 31 is connected to the bottom outlet of the wastewater storage tank 23, and a sixth control valve 232 is installed on the connecting pipeline. The outlet of the reverse osmosis pressure pump 31 is connected to the inlet of the reverse osmosis membrane main unit 32, and a first check valve 311 and an eighth control valve 312 are installed on the connecting pipeline. The inlet of the cleaning circulation pump 42 is connected to the bottom outlet of the reverse osmosis membrane cleaning agent storage tank 41, and a sixth ordinary valve 412 is installed on the connecting pipeline. The outlet of the cleaning circulation pump 42 is connected to the inlet of the reverse osmosis membrane main unit 32, and a second check valve 421 and an eleventh control valve 421 are installed on the connecting pipeline. The reverse osmosis membrane cleaning agent storage tank 41 is equipped with a third high / low liquid level sensor 411. When the liquid level is detected to be below the low level, an alarm is triggered and the eleventh control valve 423 and the cleaning circulation pump 42 are shut off. When the liquid level is detected to be above the high level, an alarm is triggered. The top inlet is connected to the cleaning agent outlet of the reverse osmosis membrane main unit 32. The connecting pipe is equipped with a fifth ordinary valve 323 and a ninth control valve 324. The reverse osmosis membrane main unit is equipped with a reverse osmosis membrane 327. The right side has an integrated automatic control system and a display panel 328 for displaying the liquid level of each liquid level sensor and the pressure values ​​of each pressure gauge, as well as the automatic control of the activated carbon filter cleaning device 5, the reverse osmosis membrane cleaning device 4, and the concentrated water secondary reuse program. There is also a manual control button 329.

[0067] Please see again. Figure 1The collection device 5 includes a concentrate collection tank 51 and a recycled water collection tank 52. The top inlet of the recycled water collection tank 52 is connected to the recycled water outlet of the reverse osmosis machine 32, and a third ordinary valve 321 is installed on the connecting pipe. A fifth high-level sensor 521 is installed inside the recycled water collection tank 52, and the sensed water level value is displayed on the control panel of the reverse osmosis machine 32. A fourth high-low level sensor 511 is installed inside the concentrate collection tank 51. The top inlet is connected to the concentrate outlet of the reverse osmosis membrane main unit 32, and a fourth ordinary valve 322, a tenth control valve 325, and a thirteenth control valve 514 are installed on the connecting pipe. The bottom outlet is connected to the inlet of the reverse osmosis pressure pump 31, and a seventh ordinary valve is installed on the connecting pipe. Valve 513 and the twelfth control valve 512: When the liquid level in the concentrate collection tank 51 reaches the high level under the detection of the fourth high, medium and low liquid level sensor 511, the tenth control valve 325 is opened, the thirteenth control valve 514 is closed, the twelfth control valve 512 is opened, and the sixth control valve 232 is closed, switching to the concentrate reuse program. When the liquid level in the concentrate collection tank 51 is lower than the low level under the detection of the fourth high, medium and low liquid level sensor 511, the seventeenth control valve 326 is opened, the tenth control valve 325 is closed, the sixth control valve 232 is opened, and the twelfth control valve 512 is closed, switching to the overflow wastewater reuse program. The outlet of the pipeline where the tenth control valve 325 is located is connected to the chromic acid reuse system.

[0068] Please see again. Figure 1 The activated carbon filter cleaning device 5 includes a desorption circulation pump 62 and an activated carbon cleaning agent storage tank 61. The inlet of the desorption circulation pump 62 is connected to the bottom outlet of the activated carbon cleaning agent storage tank 61, and a second ordinary valve 623 is installed on the connecting pipe. The outlet of the desorption circulation pump 62 is connected to the top cleaning agent inlet of the activated carbon filter 211, and a third check valve 622 and a fourteenth control valve 621 are installed on the connecting pipe. A sixth high-level liquid level sensor 611 is installed inside the activated carbon cleaning agent storage tank 61. When the liquid level is detected to be below the middle level, an alarm will be triggered and the fourteenth control valve 621 and the desorption circulation pump 62 will be closed. When the pressure gauge 211 reading is higher than 1 MPa, an alarm will be issued by the reverse osmosis membrane main unit control panel 328 to start the activated carbon cleaning program, close the third control valve 151, centrifugal pump 15, seventh control valve 242, and fourth control valve 212, and open the fourteenth control valve 621 and fifth control valve 213 to start the circulation desorption until the pressure gauge reading is lower than 0.5 MPa. For details, please refer to the automatic control operation steps.

[0069] The control valves installed in the pipelines (pipelines) of the present invention are all solenoid valves, which are electrically connected to the PLC control circuit, and the ordinary valves installed are all ball valves.

[0070] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims

1. A control method for a plastic electroplating chromium roughening washing water recovery system overflow washing water system, characterized in that, The overflow washing water recovery system of the plastic electroplating chromium roughening washing tank includes a washing and transfer device, a filtration device, a reverse osmosis device, a reverse osmosis membrane cleaning device, a collection device, and an activated carbon cleaning device connected in sequence. The cleaning and transfer device includes interconnected primary overflow cleaning tank, secondary overflow cleaning tank, tertiary overflow cleaning tank, and overflow water transfer tank, used for spray washing of plated parts and collection of overflow water for reuse. The pipeline connecting the inlet of the tertiary overflow cleaning tank and the overflow water transfer tank is equipped with a second control valve and a bypass pipeline first control valve. The overflow water transfer tank is equipped with a first high and low liquid level sensor. The pipeline connected to the primary bag filter of the filtration device is equipped with a first ordinary valve, a centrifugal pump, a check valve, and a third control valve. When the liquid level is detected to be higher than the high level, the first control valve is opened and the second control valve is closed. When the liquid level is detected to be lower than the low level, an alarm is triggered and the third control valve and the centrifugal pump are closed. The filtration device comprises a primary bag filter, a secondary activated carbon filter, a tertiary bag filter, and a wastewater storage tank connected in sequence. It is used to remove organic matter, impurities, and store pre-treated overflow wash water. The primary bag filter is equipped with a third pressure gauge, the secondary activated carbon filter with a first pressure gauge, and the tertiary bag filter with a second pressure gauge. A seventh control valve is installed on the connecting pipeline between the primary and secondary activated carbon filters, and a fourth control valve is installed on the connecting pipeline between the secondary and tertiary bag filters. The outlet of the tertiary bag filter is connected to the wastewater storage tank. A second ordinary valve is installed on the connecting pipeline; a second high and low liquid level sensor is installed in the wastewater storage tank; overflow water passes through a first-stage bag filter, a second-stage activated carbon filter and a third-stage bag filter in sequence before entering the wastewater storage tank. When the pressure values ​​of the third pressure gauge and the second pressure gauge exceed 0.5 MPa, the consumables are replaced. When the pressure value of the pressure gauge exceeds 1 MPa, the cleaning system of the activated carbon filter is started. When the liquid level in the wastewater storage tank reaches the high level under the detection of the high and low liquid level sensor, an alarm is issued and the third control valve is closed. When the liquid level reaches the low level, the eighth control valve and the reverse osmosis pressure pump are closed. The reverse osmosis device includes a reverse osmosis pressure pump and a reverse osmosis membrane unit. The inlet of the reverse osmosis pressure pump is connected to the outlet at the bottom of the wastewater storage tank and a sixth control valve is installed on the connecting pipe. The outlet of the reverse osmosis pressure pump is connected to the inlet of the reverse osmosis membrane unit and a first check valve and a seventh control valve are installed on the connecting pipe. The top inlet is connected to the cleaning agent outlet of the reverse osmosis membrane unit. The outlet pipe is equipped with a fifth ordinary valve and a ninth control valve. The reverse osmosis membrane unit is equipped with a reverse osmosis membrane. An integrated automatic control system and a display panel are provided on one side to display the liquid level of each liquid level sensor and the pressure value of each pressure gauge, as well as to automatically control the activated carbon filter cleaning device, the reverse osmosis membrane cleaning device, and the concentrated water secondary reuse program. There are also manual control buttons. The collection device includes a concentrate collection tank and a recycled water collection tank. The top inlet of the recycled water collection tank is connected to the recycled water outlet of the reverse osmosis unit, and a third ordinary valve is installed on the connecting pipe. A fifth high-level sensor is installed inside the recycled water collection tank, and the sensed water level value is displayed on the reverse osmosis unit control panel. A fourth high-low level sensor is installed inside the concentrate collection tank. The top inlet is connected to the concentrate outlet of the reverse osmosis membrane unit, and a fourth ordinary valve, a tenth control valve, and a thirteenth control valve are installed on the connecting pipe. The bottom outlet is connected to the inlet of the reverse osmosis pressure pump, and a seventh... The ordinary valve and the twelfth control valve, when the liquid level in the concentrate collection tank reaches the high level as detected by the fourth high, medium and low liquid level sensor, open the tenth control valve, close the thirteenth control valve, open the twelfth control valve, and close the sixth control valve, switching to the concentrate reuse program; when the liquid level in the concentrate collection tank is lower than the low level as detected by the fourth high, medium and low liquid level sensor, open the seventeenth control valve, close the tenth control valve, open the sixth control valve, and close the twelfth control valve, switching to the overflow wastewater reuse program. The outlet of the pipeline where the tenth control valve is located is connected to the chromic acid reuse system. The activated carbon cleaning device includes a desorption circulation pump and an activated carbon cleaning agent storage tank. The inlet of the desorption circulation pump is connected to the outlet at the bottom of the activated carbon cleaning agent storage tank, and an eighth ordinary valve is installed on the connecting pipe. The outlet of the desorption circulation pump is connected to the cleaning agent inlet at the top of the activated carbon filter, and a third check valve and a fourteenth control valve are installed on the connecting pipe. A sixth high-level liquid level sensor is installed in the activated carbon cleaning agent storage tank. When the liquid level is detected to be below the middle level, an alarm is triggered and the fourteenth control valve and the desorption circulation pump are closed. When the pressure gauge reading is higher than 1 MPa, an alarm is triggered by the reverse osmosis membrane main unit control panel to start the activated carbon cleaning program, close the third control valve, the centrifugal pump, the third control valve, and the fourth control valve, and open the fourteenth control valve and the fifth control valve to start the circulation desorption until the pressure gauge reading is lower than 0.5 MPa. The control method includes the following steps: (1) System power-on startup; (2) Detect the data from the first high and low liquid level sensor; (2.1) Determine whether the liquid level is higher than the high level. If yes, open the first control valve, close the second control valve, and return to step (2); if no, close the first control valve, open the second control valve, and return to step (2). (2.2) Determine if the liquid level is below the low level. If yes, close the third control valve, turn on the centrifugal pump, and wait 15 minutes before returning to step (2). If no, proceed to the next step (3). (3) Detect the data from the third and second pressure gauges; (4) Check the data from the first pressure gauge; (4.1) Determine if the pressure exceeds the limit. If so, open the desorption circulation pump, the fourteenth control valve, the fifth control valve, and close the third control valve and the centrifugal pump. After the activated carbon circulation desorption system has been working for 30 minutes, return to step (4). If not, open the centrifugal pump, the third control valve, the fourth control valve, and the seventh control valve. (5) Detect data from the second high and low liquid level sensor; (5.1) Determine whether the liquid level is higher than the high level. If yes, close the sixteenth control valve, open the second normal valve, and return to step (5); if no, close the second normal valve, open the sixteenth control valve, and return to step (5). (5.2) Determine if the liquid level is below the low level. If yes, shut down the reverse osmosis pressure pump and the eighth control valve, and wait 20 minutes before returning to step (5). If no, proceed to the next step (6). (6) Detect the pressure data of the reverse osmosis unit; (6.1) Determine if the pressure exceeds the limit. If so, close the reverse osmosis pressure pump, the third ordinary valve, the thirteenth control valve, and the eighth control valve, and open the cleaning circulation pump, the seventeenth control valve, and the ninth control valve. The reverse osmosis membrane circulation cleaning system will work for 30 minutes and then return to step (6). If not, close the cleaning circulation pump, the seventeenth control valve, and the ninth control valve, and open the reverse osmosis pressure pump, the third ordinary valve, the thirteenth control valve, and the eighth control valve. (7) Operate the reverse osmosis recovery system; (8) Detect the data from the fourth high and low liquid level sensor; (8.1) Determine if the liquid level is higher than the high level. If not, return to the running step (7); if so, close the sixth control valve and the thirteenth control valve, open the twelfth control valve and the tenth control valve, and proceed to the next step (9). (9) Operate the concentrate recovery system; (10) Detect the data from the fourth high and low liquid level sensor; (10.1) Determine if the liquid level is below the low level. If not, return to step (9); if so, close the twelfth and tenth control valves, open the sixth and thirteenth control valves, and return to step (6).

11. The recycled water produced by the system will be stored in recycled water collection buckets.

2. The control method for the overflow wash water recovery system of the plastic electroplating chromium roughening wash tank according to claim 1, characterized in that, The circulating desorption solution in the activated carbon circulating desorption system described in step (4.1) is an aqueous solution containing sodium hypochlorite and sodium hydroxide, with a sodium hypochlorite concentration of 1-3% and a sodium hydroxide concentration of 3-5%.

3. The control method for the overflow wash water recovery system of the plastic electroplating chromium roughening wash tank according to claim 1, characterized in that, The circulating cleaning fluid in the reverse osmosis membrane circulating cleaning system described in step (6.1) is an aqueous solution containing sodium hypochlorite and sodium hydroxide, with a sodium hypochlorite concentration of 1-3% and a sodium hydroxide concentration of 5-7%, and 0.0001-0.0006% scale inhibitor is added.

4. The control method for the overflow wash water recovery system of the plastic electroplating chromium roughening wash tank according to any one of claims 1 to 3, characterized in that, The control valves installed in each pipeline are all solenoid valves, which are electrically connected to the PLC control circuit. The ordinary valves installed are all ball valves.

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