A kind of ultrafiltration reverse osmosis combined water reuse treatment equipment

Abstract

The application relates to the technical field of water deep treatment and membrane separation equipment, in particular to a reclaimed water reuse treatment equipment combined with ultrafiltration and reverse osmosis, which comprises a raw water tank arranged on a rack, the water outlet end of the raw water tank is sequentially communicated with a pretreatment assembly, an ultrafiltration water inlet pump and an ultrafiltration membrane assembly; a reverse osmosis treatment unit arranged downstream of a steady flow switching tank; a hydraulic time-delay switching assembly arranged in the steady flow switching tank. Compared with the prior art, the steady flow switching tank and the hydraulic time-delay switching assembly are arranged between the ultrafiltration membrane assembly and the reverse osmosis treatment unit, so that the initial ultrafiltration water after each start or backwashing is returned to the raw water tank through a backflow port, compared with the mode of controlling the shunting through only the instantaneous turbidity or time signal, the preset switching amount is determined by the transition cavity volume, the floating stroke and the backflow section flow.

Description

Technical Field

[0001] This invention relates to the field of water deep treatment and membrane separation equipment technology, and in particular to a wastewater reuse treatment equipment that combines ultrafiltration and reverse osmosis. Background Technology

[0002] With the increasing demand for water in industrial production and the growing requirements for wastewater treatment, further purifying and reusing industrial wastewater, domestic wastewater, or other biochemically treated reclaimed water for cleaning, cooling, liquid preparation, or auxiliary production processes has become an important way to reduce fresh water consumption and wastewater discharge. Existing reclaimed water reuse equipment typically sets up ultrafiltration membrane modules and reverse osmosis membrane modules in sequence after bar screens, sedimentation, sand filtration, or activated carbon filtration. The ultrafiltration membrane module removes suspended solids, colloids, and some large molecular pollutants in the water, while the reverse osmosis membrane module removes dissolved salts and small molecular pollutants, thereby obtaining product water that meets the reuse requirements.

[0003] Among the existing publicly available technologies, US Patent 3133132A discloses a high-flux porous membrane for separating water from brine, reflecting that reverse osmosis membrane separation technology itself is a relatively mature technology. Most existing ultrafiltration and reverse osmosis combined equipment also directly transport ultrafiltration permeate to the reverse osmosis membrane module through a permeate pipe, or set up an ordinary intermediate water tank between the two and control the start and stop of the high-pressure pump through a liquid level switch.

[0004] During equipment operation, the applicant discovered that in the initial stages after the ultrafiltration membrane module is restarted following a shutdown, or after backwashing or chemical cleaning, backwash water, cleaning residue, loosened contaminants, and gas-water mixtures may remain in the membrane chamber and permeate pipe. The turbidity, flow rate, and pressure of the initial ultrafiltration permeate usually take some time to stabilize. If this initial permeate directly enters the reverse osmosis membrane module, contaminants are likely to accumulate at the front-end membrane element of the reverse osmosis membrane module, and the high-pressure pump may be affected by gas-water mixture flow or pressure fluctuations. Although turbidity sensors and electric diverter valves can be used for detection and diversion, contaminants easily adhere to the sensor surface, and the detection results are affected by the uniformity of the water sample and the response time. Furthermore, the control program still needs to re-judge and switch after backwashing. If the sensor, actuator, or control program malfunctions, the initial permeate may mistakenly enter the reverse osmosis membrane module. Therefore, the core issue that needs to be addressed is how to make ultrafiltration backwashing, initial permeate return, and stable permeate supply form a continuous and interconnected process that does not rely on water quality sensors and can automatically reset. Summary of the Invention

[0005] In view of this, the purpose of this invention is to propose a wastewater recycling treatment device that combines ultrafiltration and reverse osmosis, in order to solve the problems of existing ultrafiltration and reverse osmosis combined equipment where the initial ultrafiltration permeate easily enters the reverse osmosis membrane module directly after the ultrafiltration membrane module is started or after backwashing, and the diversion by sensors and electric valves has problems such as detection delay, inaccurate fouling, and insufficient reliability of reset after backwashing.

[0006] To achieve the above objectives, this invention provides a combined ultrafiltration and reverse osmosis wastewater treatment device, comprising a raw water tank mounted on a frame, the outlet of which is sequentially connected to a pretreatment component, an ultrafiltration feed pump, and an ultrafiltration membrane assembly; the permeate end of the ultrafiltration membrane assembly is connected to a flow stabilization switching tank via a permeate pipe; a reverse osmosis treatment unit located downstream of the flow stabilization switching tank, which receives the stable ultrafiltration permeate output from the flow stabilization switching tank and transports the reverse osmosis permeate to the wastewater tank; and a hydraulic delay switching component located at the flow stabilization switching tank. Inside the switching tank, in the initial state after the ultrafiltration membrane module is started, the ultrafiltration permeate entering the steady flow switching tank is directed to the raw water tank. After the cumulative amount of water entering the steady flow switching tank reaches the preset switching amount, the ultrafiltration permeate is directed to the reverse osmosis treatment unit. The clear water energy storage reset component is connected to the permeate end of the steady flow switching tank and the ultrafiltration membrane module. It is used to store stable ultrafiltration permeate during the normal permeate production stage. During the ultrafiltration backwashing stage, it drives the stored stable ultrafiltration permeate to pass through the ultrafiltration membrane module in reverse. The hydraulic delay switching component is restored to its initial state by the water discharge stroke.

[0007] Preferably, the constant flow switching tank is provided with a partition plate, which divides the constant flow switching tank into a transition chamber at the bottom and a water supply chamber at the top. The partition plate is provided with a switching cylinder that connects the transition chamber and the water supply chamber. The switching cylinder has a reflux port on its wall in the transition chamber and a water supply port on its wall in the water supply chamber. The reflux port is connected to the raw water tank through a reflux pipe, and the water supply chamber is connected to the reverse osmosis treatment unit.

[0008] Preferably, the hydraulic delay switching assembly has a sliding valve sleeve slidably sleeved on the outside of the switching cylinder, a floating ring is provided in the transition cavity, the floating ring is connected to the sliding valve sleeve by at least two connecting rods spaced apart along the circumference, the connecting rods pass through guide holes provided on the partition plate, a return spring is provided between the sliding valve sleeve and the partition plate, the sliding valve sleeve is in the initial position of opening the return port and closing the water supply port under the action of the return spring, the floating ring drives the sliding valve sleeve to move to the water supply position of closing the return port and opening the water supply port as the water level in the transition cavity rises.

[0009] Preferably, a detachable throttling reflux component is provided between the reflux port and the reflux pipe. The water passage area of ​​the throttling reflux component is smaller than that of the product water pipe, so that the initial ultrafiltration product water after the ultrafiltration membrane module is started is discharged through the reflux pipe while the water level gradually rises in the transition chamber. The effective cross-sectional area of ​​the transition chamber, the lifting stroke of the floating ring, and the water passage area of ​​the throttling reflux component together limit the preset switching amount.

[0010] Preferably, a locking groove is provided on the outer side of the sliding valve sleeve, and an elastic locking pin corresponding to the locking groove is provided in the flow stabilization switching tank. When the sliding valve sleeve moves to the water supply position, the elastic locking pin is inserted into the locking groove to restrict the sliding valve sleeve from moving to the initial position during the normal water supply stage.

[0011] Preferably, the clear water energy storage reset assembly has a clear water energy storage device connected to the water supply chamber. The clear water energy storage device is provided with a diaphragm that divides its interior into a water storage chamber and an elastic chamber. An energy storage spring is provided in the elastic chamber. A reset rod extending to one side of the elastic locking pin is connected to the diaphragm. When the ultrafiltration permeate enters the water storage chamber, the diaphragm is driven to compress the energy storage spring. When the water storage chamber is drained, the energy storage spring drives the diaphragm and the reset rod to move, so that the reset rod pushes the elastic locking pin out of the locking groove.

[0012] Preferably, the water storage chamber is connected to the product water end of the ultrafiltration membrane module through a backwash pipe. A backwash valve and a check valve are sequentially arranged on the backwash pipe along the backwash water flow direction. After the backwash valve is opened, the energy storage spring drives the diaphragm to press the stable ultrafiltration product water in the water storage chamber into the ultrafiltration membrane module through the backwash pipe, and simultaneously drives the reset rod to release the locking of the sliding valve sleeve. The sliding valve sleeve returns to its initial position under the action of the return spring.

[0013] Preferably, the reverse osmosis treatment unit has a security filter, a high-pressure pump and a reverse osmosis membrane module connected in sequence to the outlet end of the water supply chamber. The product water end of the reverse osmosis membrane module is connected to the recycled water tank, and the concentrate end of the reverse osmosis membrane module is connected to a concentrate pipe. The concentrate pipe is used to transport the reverse osmosis concentrate to the concentrate collection facility or to the raw water tank according to a set ratio.

[0014] Preferably, the permeate pipe is connected to the transition chamber through an inlet tangentially set on the side wall of the transition chamber. An annular guide plate arranged around the switching cylinder is provided in the transition chamber. An annular gap is formed between the annular guide plate and the inner wall of the flow stabilization switching tank to allow the initial ultrafiltration permeate to flow downward. The annular guide plate is used to weaken the direct water flow impact at the inlet and guide the initial ultrafiltration permeate to flow circumferentially along the transition chamber.

[0015] The beneficial effects of this invention are: This invention sets up a steady flow switching tank and a hydraulic delay switching component between the ultrafiltration membrane module and the reverse osmosis treatment unit. This allows the initial ultrafiltration permeate to return to the raw water tank through the reflux port after each startup or backwash. The switching is then completed by driving the floating ring and sliding valve sleeve based on the cumulative water volume entering the transition chamber. Compared to the method of controlling the diversion only through instantaneous turbidity or time signals, the preset switching amount is determined by the transition chamber volume, floating stroke, and reflux throttling flow rate. It is not affected by sensor surface contamination, short-term water quality fluctuations, and detection response delays, and can stably isolate the first stage of permeate and startup pressure shocks.

[0016] This invention stores stable ultrafiltration permeate that has completed the first stage of reflux during the normal water supply phase using a clear water accumulator. This permeate is released by the accumulator spring during the backwashing of the ultrafiltration membrane module, so that the backwash water is not directly taken from the raw water or reverse osmosis concentrate. This reduces the possibility of contaminants re-entering the ultrafiltration membrane module and allows the clear water accumulator to absorb instantaneous pressure changes in the water supply chamber, thereby reducing the flow and pressure fluctuations at the high-pressure pump inlet.

[0017] This invention mechanically links the water discharge stroke of the water storage tank with the unlocking action of the elastic locking pin. Once the ultrafiltration backwash is performed, the reset rod pushes the elastic locking pin out of the locking groove, causing the sliding valve sleeve to automatically return to the first stage of product water return state. Therefore, backwashing, reset and the next round of initial product water isolation do not require separate control commands, which can avoid the omission of reset after backwashing or the valve being mistakenly in the water supply position, and make the core protection action of the equipment form a continuous closed loop. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure and waterway connection of the present invention; Figure 2 This is a cross-sectional view of the flow stabilization switching tank of the present invention in its initial reflux state; Figure 3 This is a cross-sectional structural diagram of the flow stabilization switching tank of the present invention when it is in a stable water supply state. Figure 4 This is an exploded structural diagram of the switching cylinder, sliding valve sleeve, and floating ring of the present invention; Figure 5 This is a top view schematic diagram of the water inlet, annular guide plate, and throttling return path of the present invention; Figure 6This is a partially enlarged structural diagram showing the mating positions of the elastic locking pin, locking groove, and reset rod of the present invention; Figure 7 This is a cross-sectional structural schematic diagram of the water storage energy storage device of the present invention when it is in the water storage energy storage state. Figure 8 This is a schematic diagram of the water flow during backwashing of the ultrafiltration membrane module and reset of the hydraulic delay switching component of the present invention; Figure 9 This is a schematic diagram of the water circuit connection of the reverse osmosis treatment unit of the present invention.

[0020] The components in the diagram are labeled as follows: 1. Frame; 2. Raw water tank; 3. Pretreatment assembly; 4. Ultrafiltration feed pump; 5. Ultrafiltration membrane assembly; 6. Product water pipe; 7. Flow stabilization switching tank; 8. Transition chamber; 9. Supply chamber; 10. Divider plate; 11. Switching cylinder; 12. Inlet; 13. Return port; 14. Supply port; 15. Sliding valve sleeve; 16. Floating ring; 17. Return spring; 18. Throttling return component; 19. Locking groove; 20. Elastic locking pin; 21. Clear water accumulator; 22. Diaphragm; 23. Accumulation spring; 24. Reset rod; 25. Backwash pipe; 26. Check valve; 27. Return pipe; 28. Security filter; 29. ​​High-pressure pump; 30. Reverse osmosis membrane assembly; 31. Reclaimed water tank; 32. Concentrate pipe; 33. Annular guide plate; 34. Backwash valve. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0022] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the term encompasses the element or object listed thereafter and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] like Figures 1 to 9As shown, the ultrafiltration and reverse osmosis combined wastewater treatment equipment includes a raw water tank 2 mounted on a frame 1. The outlet of the raw water tank 2 is sequentially connected to a pretreatment component 3, an ultrafiltration feed pump 4, and an ultrafiltration membrane assembly 5. The permeate end of the ultrafiltration membrane assembly 5 is connected to a constant flow switching tank 7 via a permeate pipe 6. A reverse osmosis treatment unit is located downstream of the constant flow switching tank 7. The reverse osmosis treatment unit receives the stable ultrafiltration permeate output from the constant flow switching tank 7 and transports the reverse osmosis permeate to the wastewater tank 31. A hydraulic delay switching component is installed inside the constant flow switching tank 7. In the initial state after the ultrafiltration membrane module 5 is started, the ultrafiltration permeate entering the steady flow switching tank 7 is directed to the raw water tank 2. After the cumulative amount of water entering the steady flow switching tank 7 reaches the preset switching amount, the ultrafiltration permeate is directed to the reverse osmosis treatment unit. The clear water energy storage reset component is connected to the permeate end of the steady flow switching tank 7 and the ultrafiltration membrane module 5. It is used to store stable ultrafiltration permeate during the normal permeate stage. During the ultrafiltration backwashing stage, it drives the stored stable ultrafiltration permeate to pass through the ultrafiltration membrane module 5 in reverse. The hydraulic delay switching component is restored to the initial state by the water discharge stroke.

[0024] In this embodiment, "initial ultrafiltration permeate" refers to the ultrafiltration permeate generated before reaching the preset switching volume during startup, backwashing completion, or resumption of operation after chemical cleaning of the ultrafiltration membrane module 5. "Stable ultrafiltration permeate" refers to the ultrafiltration permeate generated after the first stage of reflux at the preset switching volume is completed and delivered to the water supply chamber 9 by the water supply port 14. The term "stable" indicates that the equipment has completed the mechanically set first stage of permeate isolation process and does not require real-time determination of water quality at every moment using a turbidity sensor.

[0025] The frame 1 can be formed by welding carbon steel powder-coated profiles or stainless steel profiles. The raw water tank 2 is installed on one side of the frame 1 or independently located near the equipment. The raw water tank 2 is used to receive the reclaimed water after pre-treatment, coagulation sedimentation, or other conventional treatment. The pretreatment component 3 can be selected from bag filters, quartz sand filters, activated carbon filters, or a combination of two or more of these devices in series, depending on the quality of the reclaimed water. The pretreatment component 3 is used to remove suspended solids with larger particle sizes and reduce the influent load of the ultrafiltration membrane module 5. The ultrafiltration feed pump 4 sends the pretreated reclaimed water into the ultrafiltration membrane module 5. The ultrafiltration membrane module 5 can be a PVDF hollow fiber membrane module, and its filtration method can be external pressure or internal pressure. Its concentrate side can be discharged according to a set cycle. The ultrafiltration permeate enters the steady flow switching tank 7 through the permeate pipe 6. During the initial startup of the equipment, the end of ultrafiltration backwashing, or the recovery operation after chemical cleaning, the hydraulic delay switching component maintains... In the initial reflux state, the water generated in this stage is first returned to the raw water tank 2. As the cumulative water volume entering the steady flow switching tank 7 increases, the hydraulic delay switching component switches to a stable water supply state under the action of water level buoyancy. Subsequently, the ultrafiltration permeate enters the reverse osmosis treatment unit. While the stable water supply is in place, a portion of the stable ultrafiltration permeate enters the clear water accumulator 21, allowing the clear water accumulator 21 to store the water volume required for the next ultrafiltration backwash. When the ultrafiltration membrane module 5 reaches the set operating time or the transmembrane pressure difference reaches the backwash condition, the ultrafiltration feed water pump 4 stops, the backwash valve 34 opens, and the clear water accumulator 21 releases the stable ultrafiltration permeate to backwash the ultrafiltration membrane module 5. At the same time, the mechanical stroke inside the clear water accumulator 21 releases the lock of the hydraulic delay switching component, so that the equipment returns to the initial reflux state after the backwash is completed. Thus, the raw water treatment, initial reflux, stable water supply, clear water accumulator, ultrafiltration backwash, and mechanical reset are cycled sequentially.

[0026] like Figures 2 to 7As shown, a partition plate 10 is provided inside the flow stabilization switching tank 7, dividing the flow stabilization switching tank 7 into a lower transition chamber 8 and an upper water supply chamber 9. A switching cylinder 11 is provided on the partition plate 10 to connect the transition chamber 8 and the water supply chamber 9. A return port 13 is opened on the cylinder wall of the switching cylinder 11 inside the transition chamber 8, and a water supply port 14 is opened on the cylinder wall of the switching cylinder 11 inside the water supply chamber 9. The return port 13 is connected to the raw water tank 2 through a return pipe 27, and the water supply chamber 9 is connected to the reverse osmosis treatment unit. The hydraulic delay switching assembly has a sliding valve sleeve 15 that is slidably sleeved on the outside of the switching cylinder 11. A floating ring 16 is provided in the transition chamber 8. The floating ring 16 is connected to the sliding valve sleeve 15 by at least two connecting rods spaced apart circumferentially. The connecting rods pass through guide holes provided on the partition plate 10. A return spring 17 is provided between the sliding valve sleeve 15 and the partition plate 10. Under the action of the return spring 17, the sliding valve sleeve 15 is in the initial position of opening the return port 13 and closing the water supply port 14. As the water level in the transition chamber 8 rises, the floating ring 16 drives the sliding valve sleeve 15 to move to the water supply position of closing the return port 13 and opening the water supply port 14. A detachable connection is provided between the return port 13 and the return pipe 27. The throttling return element 18 has a smaller water flow area than the product water pipe 6, so that the initial ultrafiltration product water after the ultrafiltration membrane module 5 starts up is discharged through the return pipe 27 while the water level gradually rises in the transition chamber 8. The effective cross-sectional area of ​​the transition chamber 8, the lifting stroke of the floating ring 16, and the water flow area of ​​the throttling return element 18 together limit the preset switching amount. A locking groove 19 is provided on the outer side of the sliding valve sleeve 15, and an elastic locking pin 20 corresponding to the locking groove 19 is provided in the flow stabilization switching tank 7. When the sliding valve sleeve 15 moves to the water supply position, the elastic locking pin 20 is inserted into the locking groove 19 to... The sliding valve sleeve 15 is restricted from moving to its initial position during the normal water supply phase; the clear water energy storage reset assembly has a clear water energy storage unit 21 that communicates with the water supply chamber 9. The clear water energy storage unit 21 is provided with a diaphragm 22 that divides its interior into a water storage chamber and an elastic chamber. An energy storage spring 23 is provided in the elastic chamber. A reset rod 24 extending to one side of the elastic locking pin 20 is connected to the diaphragm 22. When the ultrafiltration permeate enters the water storage chamber, the diaphragm 22 is driven to compress the energy storage spring 23. When the water storage chamber is drained, the energy storage spring 23 drives the diaphragm 22 and the reset rod 24 to move, so that the reset rod 24 pushes the elastic locking pin 20 out of the locking groove 19.

[0027] The flow-stabilizing switching tank 7 can be made of 304 stainless steel, 316L stainless steel, or fiberglass with an anti-corrosion lining. The partition plate 10 is sealed to the inner wall of the flow-stabilizing switching tank 7 to prevent the initial product water in the transition chamber 8 from bypassing the switching cylinder 11 and directly entering the water supply chamber 9. The switching cylinder 11 passes vertically through the partition plate 10. The lower end of the switching cylinder 11 is connected to the transition chamber 8, and the upper end of the switching cylinder 11 extends into the water supply chamber 9. The upper end of the switching cylinder 11 or the corresponding end of the sliding valve sleeve 15 is provided with a sealing structure to prevent water in the transition chamber 8 from bypassing the return port 13 and the water supply port 14 from the end of the switching cylinder 11 and directly entering the water supply chamber 9. The sliding valve sleeve 15 can be made of PVDF, POM, or stainless steel. A water-resistant sealing ring and guide strip are provided between the sliding valve sleeve 15 and the switching cylinder 11 to allow it to rise and fall stably along the switching cylinder 11 and respectively block the return port 13 and the water supply port 14. Figure 2 In the initial state shown, the return spring 17 pushes the sliding valve sleeve 15 downwards, blocking the water supply port 14 at the top, while the return port 13 is open. The initial permeate water generated by the ultrafiltration membrane module 5 enters the transition chamber 8 and returns to the raw water tank 2 mainly through the return port 13, the throttling return element 18, and the return pipe 27. Since the water flow capacity of the throttling return element 18 is less than the water inlet capacity of the permeate pipe 6, the water level in the transition chamber 8 rises slowly. The buoyancy of the floating ring 16 increases with the immersion depth. When the buoyancy overcomes the weight of the sliding valve sleeve 15 and the elastic force of the return spring 17, the floating ring 16 drives the sliding valve sleeve 15 to move upwards. During the movement, the return port 13 gradually decreases while the water supply port 14 gradually opens, so that the water flow smoothly transitions from the return state to the supply state, avoiding water hammer caused by the instantaneous switching of the two flow paths. When the sliding valve sleeve 15 reaches Figure 3 When the position is shown, the elastic locking pin 20 is inserted into the locking groove 19, and the sliding valve sleeve 15 is held in the position of closing the return port 13 and opening the water supply port 14. Subsequently, the stable ultrafiltration water enters the water supply chamber 9 through the switching cylinder 11 and the water supply port 14.

[0028] At least two connecting rods are provided between the floating ring 16 and the sliding valve sleeve 15, spaced apart circumferentially. The connecting rods pass through guide holes on the partition plate 10. A water-resistant guide sleeve can be installed in the guide hole. A fitting clearance is left between the connecting rod and the guide hole to ensure axial sliding and limit radial swing. The connecting rods are preferably evenly arranged circumferentially along the floating ring 16 so that the buoyancy force on the floating ring 16 is transmitted to the sliding valve sleeve 15 more evenly, and the skew and jamming during the lifting and lowering process are reduced.

[0029] The preset switching amount can be determined based on the volume of the ultrafiltration membrane module 5, the length of the product water pipe 6, and the amount of backwash residual water. In one embodiment, the diameter of the steady flow switching tank 7 is 300 mm to 1200 mm, the effective lifting stroke of the floating ring 16 is 40 mm to 150 mm, and the throttling return element 18 adopts a cylindrical throttling element with a replaceable orifice plate. The orifice plate diameter can be selected in the range of 2 mm to 10 mm, so that the initial product water volume returned to the original water tank 2 after each start-up is equivalent to 0.5% to 3% of the rated hourly product water volume of the ultrafiltration membrane module 5, or the initial return lasts for 30 seconds to 3 minutes. In actual equipment, the preset switching amount can be changed by replacing the orifice plate with a different orifice plate or adjusting the initial height of the floating ring 16. This adjustment is a mechanical setting during the equipment installation and commissioning process, and does not require the turbidity sensor to send a switching signal during normal operation.

[0030] To ensure that the water level in the transition chamber 8 can continuously rise during the initial reflux stage, the throttling reflux element 18 should be selected based on the actual permeate flow rate of the ultrafiltration membrane module 5 and the working pressure difference of the reflux pipe 27, and not solely on the pipe diameter. Within the normal operating pressure range of the equipment, the maximum reflux flow rate of the throttling reflux element 18 should be less than the minimum stable permeate flow rate of the ultrafiltration membrane module 5, so that the net inlet flow rate of the transition chamber 8 meets the following requirements: Wherein, Q_net is the net influent flow rate of transition chamber 8, Q_UF is the permeate flow rate of ultrafiltration membrane module 5, and Q_r is the reflux flow rate of throttling reflux device 18 under the corresponding operating pressure difference. When Q_net is greater than zero, the water level in transition chamber 8 gradually rises while the initial ultrafiltration permeate is continuously refluxed.

[0031] When neglecting water surface fluctuations, instantaneous flow rate changes during the movement of the sliding valve sleeve 15, and structural volume changes, the hydraulic delay switching time and the corresponding preset switching amount can be approximately determined according to the following formula: Where t_s is the switching time required to move from the initial position to the water supply position, A_e is the effective horizontal cross-sectional area of ​​the transition chamber 8, H is the effective water level stroke required for the floating ring 16 to reach the water supply position, and V_s is the preset switching amount. During actual commissioning, the throttling orifice diameter, the initial height of the floating ring 16, and the effective stroke can be corrected by combining the retention volume of the ultrafiltration membrane module 5 and the product water pipe 6, the amount of backwash residual water, and the first-stage product water quality recovery test.

[0032] The water accumulator 21 is installed on one side of the flow stabilization switching tank 7. The water storage chamber of the water accumulator 21 is connected to the water supply chamber 9. The diaphragm 22 can be made of EPDM, nitrile rubber, or other elastic materials with water resistance and cleaning agent resistance. The energy storage spring 23 is located on the side of the diaphragm 22 away from the water storage chamber. The reset rod 24 can be fixed to the pressure plate at the center of the diaphragm 22 and extends out of the water accumulator 21 through the sealing guide sleeve. When the stable ultrafiltration permeate in the water supply chamber 9 enters the water storage chamber, the water pressure pushes the diaphragm 22 to compress the energy storage spring 23, causing the water accumulator 21 to gradually store water. The reset rod 24 moves away from the diaphragm 22. The elastic locking pin 20 moves in a direction that does not interfere with the locking of the sliding valve sleeve 15. When the water storage chamber releases backwash water, the energy storage spring 23 pushes the diaphragm 22 to move in the opposite direction. The reset rod 24 moves toward the elastic locking pin 20 along with the diaphragm 22 and pushes the unlocking end of the elastic locking pin 20 through the reversing member, so that the elastic locking pin 20 is removed from the locking groove 19. After the sliding valve sleeve 15 loses its lock, it descends under the action of the return spring 17. Since the water in the transition chamber 8 can continue to be slowly discharged back to the original water tank 2 through the throttling return member 18, the floating ring 16 also descends with the water level, eventually causing the return port 13 to reopen and the water supply port 14 to close again.

[0033] The interface in the water accumulator 21 that connects to the treated water is located on one side of the water storage chamber. The backwash pipe 25 is connected to the interface of the water storage chamber. The elastic chamber does not participate in the storage and transportation of treated water. The water filling passage from the water supply chamber 9 to the water storage chamber can be equipped with a one-way valve that only allows stable ultrafiltration permeate to enter the water storage chamber. The one-way valve 26 on the backwash pipe 25 only allows water to flow from the water storage chamber to the permeate end of the ultrafiltration membrane module 5, thereby preventing water from flowing back into the water supply chamber 9 during the backwashing stage or forming a bypass through the permeate pipe 6.

[0034] like Figure 1 , Figures 6 to 8 As shown, the water storage chamber is connected to the product water end of the ultrafiltration membrane module 5 through the backwash pipe 25. The backwash pipe 25 is provided with a backwash valve 34 and a one-way valve 26 in sequence along the backwash water flow direction. After the backwash valve 34 is opened, the energy storage spring 23 drives the diaphragm 22 to press the stable ultrafiltration product water in the water storage chamber into the ultrafiltration membrane module 5 through the backwash pipe 25, and simultaneously drives the reset rod 24 to release the locking of the sliding valve sleeve 15. The sliding valve sleeve 15 returns to the initial position under the action of the return spring 17.

[0035] During normal water production, backwash valve 34 is closed, and check valve 26 prevents water in product water pipe 6 from bypassing backwash pipe 25 directly. Stable ultrafiltration product water enters clear water accumulator 21 from water supply chamber 9 and compresses accumulator spring 23. The effective water storage volume of clear water accumulator 21 can be set to 1.05 to 1.5 times the water volume required for a single backwash of ultrafiltration membrane module 5 to ensure sufficient pressure margin during backwashing. When the equipment enters the backwashing program, ultrafiltration feed pump 4 stops, concentrate discharge passage of ultrafiltration membrane module 5 is opened, backwash valve 34 opens, and accumulator spring 23 pushes diaphragm 22 to store water. The stable ultrafiltration permeate in the chamber is sent to the permeate side of the ultrafiltration membrane module 5 through the one-way valve 26, so that the water passes through the membrane wall in reverse from the permeate side of the ultrafiltration membrane and carries away the attached pollutants from the concentrate side. Before the diaphragm 22 approaches the end of the water discharge, the reset rod 24 has pushed the elastic locking pin 20 out of the locking groove 19. Therefore, the backwashing action itself constitutes the reset driving force of the hydraulic delay switching component. After the backwashing is completed, even if the control system does not send a reset signal to the diversion valve, the steady flow switching tank 7 has returned to the initial state of the return port 13 being open. The water generated first during the next startup will inevitably return to the original water tank 2 through the return pipe 27.

[0036] When backwashing begins, the ultrafiltration feed pump 4 stops operating, interrupting the feed water flow into the transition chamber 8. After the reset rod 24 disengages the elastic locking pin 20 from the locking groove 19, the return spring 17 first drives the sliding valve sleeve 15 to produce an initial downward displacement, causing the return port 13 to open at least partially. The water in the transition chamber 8 is then discharged through the throttling return element 18 and the return pipe 27. The drop in water level reduces the effective buoyancy of the floating ring 16, and the sliding valve sleeve 15 continues to descend under the action of the return spring 17 and eventually returns to its initial position. The preload and stiffness of the return spring 17 are set to overcome the sliding friction resistance and residual hydraulic resistance of the sliding valve sleeve 15, connecting rod, and floating ring 16 after the ultrafiltration feed pump 4 stops and the elastic locking pin 20 is released, allowing the sliding valve sleeve 15 to move at least to the position where the return port 13 begins to open.

[0037] The effective water storage capacity and discharge terminal pressure of the clear water accumulator 21 can be determined according to the backwashing requirements of the ultrafiltration membrane module 5, and must at least meet the following requirements: Wherein, V_a is the effective available water storage capacity of the water accumulator 21, Q_b is the required backwash flow rate of the ultrafiltration membrane module 5, t_b is the duration of a single backwash, k is the water storage margin coefficient, which can be taken as 1.05 to 1.50, P_min is the discharge end pressure of the water accumulator 21, P_b is the minimum backwash pressure required by the ultrafiltration membrane module 5, and ΔP_l is the total pressure loss generated by the backwash pipe 25, backwash valve 34, and check valve 26. The preload, stiffness, and effective pressure-bearing area of ​​the accumulator spring 23 and the diaphragm 22 are selected accordingly, and the maximum working pressure of the water accumulator 21 is ensured not to exceed the rated pressure values ​​of the tank, diaphragm, pipe fittings, and ultrafiltration membrane module 5.

[0038] like Figure 1 , Figure 5 and Figure 9 As shown, the reverse osmosis treatment unit has a security filter 28, a high-pressure pump 29, and a reverse osmosis membrane module 30 connected sequentially to the outlet of the water supply chamber 9. The product water end of the reverse osmosis membrane module 30 is connected to the recycled water tank 31, and the concentrate end of the reverse osmosis membrane module 30 is connected to a concentrate pipe 32. The concentrate pipe 32 is used to transport the reverse osmosis concentrate to the concentrate collection facility or to the raw water tank 2 according to a set ratio. The product water pipe 6 is connected to the transition chamber 8 through an inlet 12 tangentially set on the side wall of the transition chamber 8. An annular guide plate 33 is arranged around the switching cylinder 11 in the transition chamber 8. An annular gap is formed between the annular guide plate 33 and the inner wall of the flow stabilization switching tank 7 to allow the initial ultrafiltration product water to flow downward. The annular guide plate 33 is used to weaken the direct water flow impact at the inlet 12 and guide the initial ultrafiltration product water to flow circumferentially along the transition chamber 8.

[0039] Water from the permeate pipe 6 enters the transition chamber 8 through the tangential inlet 12 and then flows circumferentially along the inner wall of the steady flow switching tank 7. The annular guide plate 33 causes the water flow to move downwards along the annular gap first, and then turn to the middle of the transition chamber 8 and the return port 13, avoiding the direct impact of the inlet jet on the floating ring 16 and causing the sliding valve sleeve 15 to rise prematurely. At the same time, the circumferential flow allows air bubbles to accumulate in the upper part of the transition chamber 8 and be discharged through the exhaust structure, allowing a small amount of loosened particles to preferentially enter the return pipe 27 with the first stage of permeate water. After the sliding valve sleeve 15 is switched to the water supply position, the stable ultrafiltration permeate enters through the water supply port 14. The water supply chamber 9 then passes through a security filter 28, a high-pressure pump 29, and a reverse osmosis membrane module 30 in sequence. The security filter 28 ultimately traps any remaining fine particles. The high-pressure pump 29 raises the ultrafiltration permeate to the operating pressure required by the reverse osmosis membrane module 30. The reverse osmosis permeate enters the recycled water tank 31 and is transported to the reuse point according to production needs. The reverse osmosis concentrate is discharged into the concentrate collection facility through the concentrate pipe 32. If the raw water salinity is permissible and a concentrate ratio control device is installed, a portion of the concentrate can also be returned to the raw water tank 2 to mix with the newly entering greywater for treatment.

[0040] An automatic air vent valve or a hydrophobic vent can be installed at the top of the water supply chamber 9 to discharge the gas introduced by the initial produced water and accumulated in the tank. The discharge capacity of the vent should match the air intake during the start-up phase and prevent continuous discharge of treated water. The high-pressure pump 29 is preferably started after the sliding valve sleeve 15 reaches the water supply position and the outlet pressure of the water supply chamber 9 reaches the minimum allowable inlet pressure of the high-pressure pump 29. This safety interlock can be implemented using a position switch and a pressure switch, which are only used to confirm the hydraulic status and do not participate in the determination of the water quality of the first stage of produced water.

[0041] After the equipment is installed, the aperture of the throttling return element 18 is selected according to the volume of the ultrafiltration membrane module 5 and the water quality recovery time after backwashing. The initial position of the floating ring 16 is adjusted. Then, the treated water is injected into the raw water tank 2 and the pretreatment module 3 and ultrafiltration feed pump 4 are started. The initial ultrafiltration permeate enters the transition chamber 8 and returns to the raw water tank 2 through the return pipe 27. After the preset switching amount is reached, the sliding valve sleeve 15 switches and locks. The stable ultrafiltration permeate enters the reverse osmosis treatment unit and the clear water accumulator 21. After the clear water accumulator 21 has completed water storage, the equipment continues to perform ultrafiltration and reverse osmosis treatment. When the backwashing conditions are met, the ultrafiltration feed pump 4 is stopped and the backwash valve 34 is opened. The clear water accumulator 21 performs reverse flushing on the ultrafiltration membrane module 5 and simultaneously resets the sliding valve sleeve 15. After the backwashing is completed, the backwash valve 34 is closed and the ultrafiltration feed pump 4 is restarted. The equipment performs the first stage of return and stable water supply process again, thus forming a periodic automatic operation process that does not rely on water quality sensors.

[0042] For normal shutdown restarts or recovery operation after water backwashing, the first stage ultrafiltration permeate can be returned to the raw water tank 2 via return pipe 27. For recovery operation after chemical cleaning, if the pH value, conductivity, or residual cleaning agent concentration of the first stage permeate does not meet the requirements for re-entering the raw water treatment process, the return pipe 27 can be temporarily switched to the cleaning waste liquid collection facility or neutralization treatment facility. After the first stage permeate reaches the preset recovery conditions, it can be switched back to the raw water tank 2 to avoid the cleaning residue circulating in the system.

[0043] In another embodiment, the water accumulator 21 can be replaced by an airbag accumulator instead of a diaphragm accumulator, and the energy storage spring 23 can be replaced by the elastic pressure formed by pre-charged gas. In this case, the reset rod 24 can be connected to the movable pressure plate at the end of the airbag. As long as the active stroke generated during water storage and discharge can drive the elastic locking pin 20 to unlock and keep the backwash action linked with the reset action of the hydraulic delay switching component, it belongs to the equivalent implementation of the technical concept of the present invention.

[0044] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0045] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A wastewater reuse treatment device combining ultrafiltration and reverse osmosis, characterized in that, include: A frame (1) is provided with a raw water tank (2). The outlet of the raw water tank (2) is connected in sequence to the pretreatment component (3), the ultrafiltration water inlet pump (4) and the ultrafiltration membrane component (5). The water production end of the ultrafiltration membrane component (5) is connected to the flow stabilization switching tank (7) through the water production pipe (6). A reverse osmosis treatment unit is provided downstream of the constant flow switching tank (7). The reverse osmosis treatment unit is used to receive the stable ultrafiltration permeate output by the constant flow switching tank (7) and transport the reverse osmosis permeate to the recycled water tank (31). The steady flow switching tank (7) is equipped with a hydraulic delay switching component. The hydraulic delay switching component is used to guide the ultrafiltration permeate entering the steady flow switching tank (7) to the raw water tank (2) in the initial state after the ultrafiltration membrane module (5) is started. After the cumulative amount of water entering the steady flow switching tank (7) reaches the preset switching amount, the ultrafiltration permeate is guided to the reverse osmosis treatment unit. A clean water energy storage and reset component is provided between the steady flow switching tank (7) and the water production end of the ultrafiltration membrane module (5). The clean water energy storage and reset component is used to store stable ultrafiltration water during the normal water production stage, drive the stored stable ultrafiltration water to flow back through the ultrafiltration membrane module (5) during the ultrafiltration backwashing stage, and use the water discharge stroke to restore the hydraulic delay switching component to the initial state.

2. The ultrafiltration-reverse osmosis combined wastewater treatment equipment according to claim 1, characterized in that, The flow stabilizing switching tank (7) is provided with a partition plate (10), which divides the interior of the flow stabilizing switching tank (7) into a transition chamber (8) located at the bottom and a water supply chamber (9) located at the top. A switching cylinder (11) connecting the transition chamber (8) and the water supply chamber (9) is vertically inserted through the partition plate (10). The switching cylinder (11) has a reflux port (13) on its cylinder wall inside the transition chamber (8), and a water supply port (14) is provided on its cylinder wall inside the water supply chamber (9). The reflux port (13) is connected to the raw water tank (2) through a reflux pipe (27), and the water supply chamber (9) is connected to the reverse osmosis treatment unit.

3. The ultrafiltration-reverse osmosis combined wastewater treatment equipment according to claim 2, characterized in that, The hydraulic delay switching assembly has a sliding valve sleeve (15) that is slidably sleeved on the outside of the switching cylinder (11) along the axial direction. A floating ring (16) is provided in the transition cavity (8). The floating ring (16) is connected to the sliding valve sleeve (15) by at least two connecting rods that are spaced apart in the circumferential direction. The connecting rods pass through the guide holes provided on the partition plate (10). A return spring (17) is provided between the sliding valve sleeve (15) and the partition plate (10). The sliding valve sleeve (15) is in the initial position of opening the return port (13) and closing the water supply port (14) under the action of the return spring (17). The floating ring (16) drives the sliding valve sleeve (15) to move upward along the switching cylinder (11) to the water supply position of closing the return port (13) and opening the water supply port (14) as the water level in the transition chamber (8) rises.

4. The ultrafiltration-reverse osmosis combined wastewater treatment equipment according to claim 3, characterized in that, A detachable throttling reflux component (18) is provided between the reflux port (13) and the reflux pipe (27). The water passage area of ​​the throttling reflux component (18) is smaller than that of the product water pipe (6), so that while the initial ultrafiltration product water after the ultrafiltration membrane module (5) is started is discharged through the reflux pipe (27), the water level gradually rises in the transition chamber (8). The effective cross-sectional area of ​​the transition cavity (8), the lifting stroke of the floating ring (16), and the water passage area of ​​the throttling return component (18) together limit the preset switching amount.

5. The ultrafiltration-reverse osmosis combined wastewater treatment equipment according to claim 3, characterized in that, The outer side of the sliding valve sleeve (15) is provided with a locking groove (19), and the side wall of the flow stabilizing switching tank (7) is provided with an elastic locking pin (20) that is radially toward the sliding valve sleeve (15). When the sliding valve sleeve (15) moves to the water supply position, the elastic locking pin (20) is inserted into the locking groove (19) to restrict the sliding valve sleeve (15) from moving to the initial position during the normal water supply phase.

6. The ultrafiltration-reverse osmosis combined wastewater treatment equipment according to claim 5, characterized in that, The clear water energy storage reset assembly has a clear water energy storage device (21) disposed outside the flow stabilization switching tank (7) and connected to the water supply chamber (9). The clear water energy storage device (21) is provided with a diaphragm (22) that divides its interior into a water storage chamber and an elastic chamber. An energy storage spring (23) is provided in the elastic chamber. A reset rod (24) is connected to the middle of the diaphragm (22). The reset rod (24) passes through the water accumulator (21) and extends to one side of the elastic locking pin (20). The reset rod (24) and the elastic locking pin (20) are in a transmission engagement. When the stable ultrafiltration permeate enters the water storage chamber, it drives the diaphragm (22) to compress the energy storage spring (23). When the water storage chamber is drained, the energy storage spring (23) drives the diaphragm (22) and the reset rod (24) to move, and the reset rod (24) drives the elastic locking pin (20) to exit the locking groove (19).

7. The ultrafiltration-reverse osmosis combined wastewater treatment equipment according to claim 6, characterized in that, The water storage chamber is connected to the water production end of the ultrafiltration membrane module (5) through a backwash pipe (25). A backwash valve (34) and a one-way valve (26) are sequentially arranged on the backwash pipe (25) along the backwash water flow direction from the water storage chamber to the ultrafiltration membrane module (5). After the backwash valve (34) is opened, the energy storage spring (23) drives the diaphragm (22) to press the stable ultrafiltration permeate in the water storage chamber into the ultrafiltration membrane assembly (5) through the backwash pipe (25), and simultaneously drives the reset rod (24) to release the locking of the elastic locking pin (20) on the sliding valve sleeve (15). The sliding valve sleeve (15) returns to the initial position under the action of the return spring (17).

8. The ultrafiltration-reverse osmosis combined wastewater treatment equipment according to claim 2, characterized in that, The reverse osmosis treatment unit has a security filter (28), a high-pressure pump (29) and a reverse osmosis membrane module (30) connected in sequence to the outlet of the water supply chamber (9). The product water end of the reverse osmosis membrane module (30) is connected to the recycled water tank (31). The concentrate end of the reverse osmosis membrane module (30) is connected to a concentrate pipe (32). The concentrate pipe (32) is used to transport the reverse osmosis concentrate to the concentrate collection facility or to the raw water tank (2) according to a set ratio.

9. The ultrafiltration and reverse osmosis combined wastewater treatment equipment according to claim 2, characterized in that, The water production pipe (6) is connected to the transition cavity (8) through the water inlet (12) tangentially disposed on the side wall of the transition cavity (8). The transition cavity (8) is provided with an annular guide plate (33) arranged around the switching cylinder (11). The annular guide plate (33) and the inner wall of the flow stabilization switching tank (7) form an annular gap for the initial ultrafiltration permeate to flow circumferentially along the transition chamber (8) and enter the bottom of the transition chamber (8) downwards. The annular guide plate (33) is used to weaken the direct water flow impact at the inlet (12) and guide the initial ultrafiltration permeate to flow circumferentially along the transition chamber (8).

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