A flat sheet membrane fatigue testing device

Abstract

The utility model provides a kind of flat sheet membrane fatigue degree testing device, comprising: test groove, is divided into raw solution cavity and water production cavity by membrane, the raw solution cavity is equipped with water inlet and backwash outlet, water production cavity is equipped with water outlet and backwash inlet;Water supply system, including raw solution supply unit and backwash liquid supply unit, the raw solution supply unit is connected by pipeline the water inlet, the backwash liquid supply unit is connected by pipeline the backwash inlet;Detection unit, including the raw solution cavity pressure sensor of being arranged at raw solution cavity and the water production cavity pressure sensor of being arranged at water production cavity;Control system, including control mechanism, the control mechanism according to the pressure value detected by raw solution cavity pressure sensor, water production cavity pressure sensor, controls raw solution supply unit, backwash liquid supply unit to realize flow path switching, repeatedly running water production, backwash operation in test groove, fatigue degree test is carried out to membrane.The flat sheet membrane fatigue degree testing device structure is reasonable, easy to operate.

Description

Technical Field

[0001] This utility model relates to the field of measurement and testing technology, and in particular to a device for testing the fatigue of a flat sheet diaphragm. Background Technology

[0002] Flat sheet membranes, as a key type of membrane separation component, are typically manufactured by uniformly coating a nonwoven fabric substrate with polymer membrane layers such as polyvinylidene fluoride (PVDF), polysulfone (PS), or polyethersulfone (PES) using a blade coating method, forming a flat sheet membrane with separation capabilities. Subsequently, precision joining techniques such as ultrasonic welding or thermoforming welding are employed to fused and seal the membrane edges to the supporting structure, ultimately assembling the membrane into a fully functional flat sheet membrane module. These products, due to their excellent separation performance and mechanical strength, are widely used in various industrial fields, including water treatment, biopharmaceuticals, and food and beverage.

[0003] In actual operation, flat-sheet membrane modules typically require frequent permeate (filtration), air flushing (stopping permeate production), and backwashing (cleaning) operations. During permeate production, the permeate is drawn out, and the membrane is compressed towards the permeate side under negative pressure, with its welded edges subjected to compressive stress. During air flushing, the membrane returns to a relaxed state, and the gas scouring the membrane causes it to experience complex alternating stresses resulting from the high-frequency vibration, disordered fluid impact, and local pressure fluctuations caused by the air flushing. During backwashing, pressurized water impacts the membrane from the permeate side in the opposite direction, pressing the membrane towards the feed liquid side, with the welded edges subjected to tensile stress or reverse bending stress. This periodic positive and negative pressure cycle causes the membrane, especially its edge welded seals, to experience significant alternating mechanical stress. Under long-term operating conditions, fatigue cracks or even rupture can easily develop at the membrane welded edges, leading to membrane module performance failure and deterioration of permeate water quality.

[0004] Currently, there is a lack of dedicated equipment for testing the fatigue resistance of flat sheet membranes (especially welded edges). Conventional membrane performance tests often focus on parameters such as flux and rejection rate, but cannot effectively simulate the repeated stress direction changes and pressure impacts experienced by the membrane in actual use. Therefore, it is difficult to pre-evaluate and screen membrane products with excellent fatigue resistance, and it is also impossible to provide effective experimental data for the structural design and welding process improvement of membranes. Utility Model Content

[0005] In view of the technical problems in the prior art, this utility model provides a flat sheet diaphragm fatigue testing device with reasonable structure and simple operation.

[0006] A device for testing the fatigue strength of a flat sheet diaphragm includes: The test tank is used to hold the flat sheet membrane to be tested. The test tank is divided into a raw liquid chamber and a product water chamber by the membrane. The raw liquid chamber is provided with an inlet and a backwash outlet, and the product water chamber is provided with a product water outlet and a backwash inlet. The water supply system includes a raw liquid supply unit and a backwash liquid supply unit. The raw liquid supply unit is connected to the water inlet through a pipeline, and the backwash liquid supply unit is connected to the backwash inlet through a pipeline. The detection unit is used to monitor parameters during the test process, including a raw liquid chamber pressure sensor installed in the raw liquid chamber and a product water chamber pressure sensor installed in the product water chamber. The control system includes a control mechanism connected to a raw liquid supply unit, a backwash liquid supply unit, a raw liquid chamber pressure sensor, and a product water chamber pressure sensor. The control mechanism controls the raw liquid supply unit and the backwash liquid supply unit to switch flow paths based on the pressure values ​​detected by the raw liquid chamber pressure sensor and the product water chamber pressure sensor. The system repeatedly runs product water and backwash operations in the test tank to perform fatigue tests on the membrane.

[0007] Preferably, the water supply system includes a water tank and an inlet pump. The water tank and the inlet pump are connected by a pipeline and communicate with the water inlet to form the raw liquid supply unit. The water tank and the inlet pump are connected by a pipeline and communicate with the backwash inlet to form the backwash liquid supply unit. The inlet pump is connected to a control mechanism, and the control mechanism controls the start and stop operation of the inlet pump.

[0008] Preferably, the outlet of the water inlet pump is connected to a main pipeline, which is then connected to two branch pipelines, which are respectively connected to the water inlet and the backwash inlet. The branch pipelines connecting the water inlet and the backwash inlet are respectively equipped with a raw liquid inlet valve and a backwash inlet valve. The control mechanism is connected to the raw liquid inlet valve and the backwash inlet valve, and the flow path is switched by controlling the switching state of the raw liquid inlet valve and the backwash inlet valve.

[0009] Preferably, the water inlet, backwash outlet, and water tank are connected by a pipeline.

[0010] Preferably, the pipelines connecting the water inlet and the backwash outlet are first connected in parallel and then merged to connect to the water tank. The parallel pipelines of the water inlet and the backwash outlet are respectively equipped with a water inlet valve and a backwash outlet valve. The control mechanism is connected to the water inlet valve and the backwash outlet valve, and the flow path is switched by controlling the flow path switching state of the water inlet valve and the backwash outlet valve.

[0011] Preferably, a flow meter for monitoring the instantaneous flow rate during water production or backwashing is installed on the parallel pipeline of the water production port and the backwash outlet.

[0012] Preferably, the system further includes an aeration simulation system, which includes an air source, a gas flow control valve, and an aeration head installed at the bottom of the raw liquid chamber of the test tank. The control mechanism is connected to the air source and the gas flow control valve to control the start and stop of the aeration simulation system and the aeration cycle.

[0013] Preferably, the test tank is made of transparent plastic.

[0014] A device for testing the fatigue strength of a flat sheet diaphragm includes: The test tank is used to hold the flat sheet membrane to be tested. The test tank is divided into a raw liquid chamber and a product water chamber by the membrane. The raw liquid chamber is provided with an inlet and a backwash outlet, and the product water chamber is provided with a product water outlet and a backwash inlet. The water supply system includes a water tank and an inlet pump. The water tank and the inlet pump are connected by pipelines and then connected to the inlet and the backwash inlet, respectively. The product water outlet, the backwash outlet and the water tank are connected by pipelines to realize water recycling. The detection unit is used to monitor parameters during the test process, including a raw liquid chamber pressure sensor installed in the raw liquid chamber, a product water chamber pressure sensor installed in the product water chamber, and a flow meter installed on the pipeline between the product water outlet, backwash outlet and water tank to monitor the instantaneous flow rate during product water or backwash. The control system includes a control mechanism and a backwash outlet valve, a product water valve, a raw liquid inlet valve, and a backwash inlet valve. These valves are connected to the backwash outlet, product water inlet, inlet, and backwash inlet, respectively, and are used to control the opening and closing of these valves. The control mechanism is connected to an inlet pump, a raw liquid chamber pressure sensor, a product water chamber pressure sensor, the backwash outlet valve, the product water valve, the raw liquid inlet valve, and a flow meter. Based on the pressure values ​​detected by the raw liquid chamber pressure sensor and the product water chamber pressure sensor, it controls the switching state of the backwash outlet valve, product water valve, raw liquid inlet valve, and backwash inlet valve, achieving flow path switching. The system automatically and repeatedly cycles through product water and backwash operations in the test tank to perform fatigue testing on the membrane. Furthermore, based on the abnormally rapid increase in instantaneous flow detected by the flow meter, it is determined that the membrane has broken due to excessive fatigue.

[0015] Preferably, it also includes an aeration simulation system, which includes an air source, a gas flow control valve, and an aeration head installed at the bottom of the raw liquid chamber of the test tank. The control mechanism is connected to the air source and the gas flow control valve to control the start and stop of the aeration simulation system and the aeration cycle. Combined with the water production and backwashing operations, it realizes the automated cyclic operation of each process of "water production-backwashing-aeration" and performs fatigue testing on the membrane.

[0016] Compared with existing technologies, the flat sheet membrane fatigue testing device provided by this utility model, through the setting of a test tank, a water supply system, a detection unit, and a control system, and the control system including a control mechanism, is connected to the raw liquid supply unit, the backwash liquid supply unit, the raw liquid chamber pressure sensor, and the permeate chamber pressure sensor. It is used to control the raw liquid supply unit and the backwash liquid supply unit to achieve flow path switching based on the pressure values ​​detected by the raw liquid chamber pressure sensor and the permeate chamber pressure sensor. The device repeatedly runs the permeate and backwash operations in the test tank to perform fatigue testing on the membrane. Therefore, the device has a reasonable structure and is easy to operate. It can accurately simulate the permeate and backwash procedures in the actual operation of the flat sheet membrane and perform accelerated fatigue testing on the membrane (especially its welded edges), thus providing a reliable means for membrane durability assessment and quality control. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a flat sheet diaphragm fatigue testing device provided in one embodiment of the present invention; Figure 2 for Figure 1 The diagram shows the structure of the test tank in the flat sheet diaphragm fatigue testing device.

[0019] In the diagram, 11. Backwash outlet valve, 12. Product water valve, 13. Raw liquid inlet valve, 14. Backwash inlet valve, 15. Water tank drain valve, 2. Flow meter, 3. Test tank, 31. Left end cover, 311. Inlet, 312. Backwash outlet, 313. Raw liquid chamber pressure sensor, 314. Aeration head, 32. Right end cover, 321. Backwash inlet, 322. Product water outlet, 323. Sealing ring, 324. Product water chamber pressure sensor, 4. Diaphragm to be tested, 5. Inlet pump, 6. Water tank. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0022] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0023] like Figure 1 , Figure 2 As shown in the figure, this utility model embodiment provides a flat sheet diaphragm fatigue testing device, which includes: a test tank 3, a water supply system, a control system, and a detection unit.

[0024] In this embodiment, the test tank 3 is composed of a left cover plate 31 and a right cover plate 32 fastened together by multiple clips, and is used to house the flat sheet membrane 4 to be tested. The test tank 3 is divided into a non-communicating feed chamber and a product water chamber by the membrane 4. The feed chamber is formed on the left side of the membrane and is provided with an inlet 311 and a backwash outlet 312. The product water chamber is formed on the right side of the membrane and is provided with a product water outlet 322 and a backwash inlet 321. The test tank 3 is made of transparent plastic, such as polymethyl methacrylate (PMMA), polypropylene (PP), or polyethylene terephthalate (PET).

[0025] In this embodiment, the water supply system includes a water tank 6 and an inlet pump 5. The water tank 6 and the inlet pump 5 are connected by pipelines and connected to the inlet 311 to form a raw liquid supply unit, and connected by pipelines and connected to the backwash inlet 321 to form a backwash liquid supply unit. The raw liquid supply unit and the backwash supply unit use the same inlet pump 5 and water tank 6, which simplifies the structure. Specifically, the outlet of the inlet pump 5 is connected to a main pipeline, which is then connected to two branch pipelines, respectively connecting to the inlet 311 and the backwash inlet 321. The product water outlet 322, the backwash outlet 312, and the water tank 6 are connected by pipelines to achieve water recycling. Specifically, the pipelines connecting the product water outlet 322 and the backwash outlet 312 are first connected in parallel and then merged to connect to the water tank 6. Reverse osmosis water can be used for testing.

[0026] In this embodiment, the detection unit is used to monitor parameters during the test process. It includes a pressure sensor 313 installed in the raw liquid chamber, a pressure sensor 324 installed in the product water chamber, and a flow meter 2 installed on the pipeline between the product water outlet, the backwash outlet and the water tank to monitor the instantaneous flow rate during product water or backwash.

[0027] In this embodiment, the control system includes a control mechanism and multiple control valves. The control mechanism can be a PLC controller, housed in an electrical control cabinet. The multiple control valves include a backwash outlet valve 14, a product water valve 12, a raw liquid inlet valve 13, and a backwash inlet valve 11, respectively connected to the backwash outlet 312, product water inlet 322, inlet 311, and backwash inlet 321 to control the opening and closing of these openings. The control mechanism connects to each control valve, issuing commands to control the switching state of each control valve's flow path, thereby switching the flow path and achieving a single inlet / outlet flow path for both the product water and backwash processes. The backwash outlet valve and product water valve, as well as the raw liquid inlet valve and backwash inlet valve, can be integrated into a multi-path valve assembly to simplify the structure. The control mechanism is also connected to a flow meter 2 to determine if the diaphragm is damaged due to excessive fatigue based on a sudden and abnormal increase in instantaneous flow rate.

[0028] Thus, the workflow implemented through the control system includes at least two parts: Water production process: Connect the outlet of the inlet pump 5 to the inlet 311 of the test tank, and simultaneously open the raw liquid inlet valve 13 and the product water valve 12 to simulate the water production process. At this time, the pressure on the raw liquid side of the membrane (P1) is higher than the pressure on the product water side (P2), forming a positive pressure difference (ΔP = P1 - P2) to drive water production.

[0029] Backwashing process: Connect the outlet of the inlet pump 5 to the backwash inlet 321 of the test tank, and simultaneously open the backwash inlet valve 14 and the backwash outlet valve 11 to simulate the backwashing process. At this time, the pressure on the membrane permeate side (P2) is higher than the pressure on the feed liquid side (P1), forming a reverse pressure difference (ΔP = P2 - P1).

[0030] In this embodiment, the device also integrates an aeration simulation system, which mainly consists of an air source, a gas flow control valve, and an aeration head 314 installed at the bottom of the raw liquid chamber of the test tank. The control mechanism is connected to the air source and the gas flow control valve to control the start and stop of the aeration simulation system and the aeration cycle.

[0031] In this embodiment, the control mechanism works in coordination with the inlet pump 5 and each pipeline valve group through an electrical connection. It is used to precisely control the channel switching status of the valve group, the start and stop operation of the inlet pump 5 and the output pressure parameters. It can also accurately set the product water pressure value, backwash pressure value and the timing control logic of each process stage, thereby realizing the automated cyclic operation function of the system and effectively simulating the actual working conditions of different intensity levels.

[0032] The working principle and usage process of the flat sheet diaphragm fatigue testing device in this embodiment are described below.

[0033] Water production process: Connect the outlet of the water inlet pump 5 to the water inlet 311 of the test tank, open the raw liquid inlet valve 13 and the water production valve 12 at the same time, close the backwash inlet valve 14 and the backwash outlet valve 11, start the water inlet pump 5, and simulate the water production process.

[0034] Backwashing process: Connect the outlet of the inlet pump 5 to the backwash inlet 321 of the test tank, open the backwash inlet valve 14 and the backwash outlet valve 11 at the same time, close the raw liquid inlet valve 13 and the product water valve 12, start the inlet pump 5, and simulate the backwashing process.

[0035] Aeration process: Turn off the inlet pump 5, close the raw liquid inlet valve 13, the product water valve 12, and the backwash inlet valve 12, open the backwash outlet valve 11, start the aeration system, and simulate the aeration and flushing process.

[0036] By precisely controlling the valve group's passage switching status, the start-stop operation of the inlet pump 5, and the output pressure parameters, the system accurately sets the product water pressure value, backwash pressure value, and the timing control logic of each process stage, thereby realizing the automated cyclic operation function of each process of "product water-backwash-aeration" and effectively simulating actual working conditions of different intensity levels.

[0037] Membrane fatigue test data feedback: The above "product water-backwash-aeration" process automatically cycles according to the set number of times. Pressure sensors and flow meters 2 monitor and record data in real time. The membrane edges can be visually inspected periodically for cracks or signs of damage through a transparent test tank.

[0038] Diaphragm fatigue test result determination: The device will automatically stop after reaching the preset number of cycles, or the test will be terminated in advance by the control system when an abnormal and rapid increase in flow rate is detected in flow meter 2 (diaphragm damage due to excessive fatigue). Diaphragm 4 will be removed and its welded edges will be inspected to evaluate its fatigue resistance.

[0039] Compared with existing technologies, the flat sheet diaphragm fatigue testing device of this embodiment has the following advantages: 1. Through the control mechanism, in coordination with the inlet pump and various pipeline valve groups, the "product water-backwash-aeration" process can be executed precisely and automatically in a cyclical manner, simulating the alternating stress conditions that the flat sheet membrane is subjected to in actual use; 2. Accelerated fatigue testing can be conducted by increasing test pressure and cycle frequency, thus shortening the test cycle. By monitoring changes in parameters such as pressure and flow rate, and ultimately observing whether the diaphragm ruptures, the fatigue life of the diaphragm can be quantitatively assessed and compared. 3. The system adopts a single pump and single water tank combined with a multi-functional valve group to realize the functions of water production supply and backwash supply, which significantly simplifies the system structure and reduces the cost of components and the size of equipment. 4. Achieve water recycling, significantly reducing water consumption during testing; 5. The device has a compact structure, high flow path integration, fully automatic control of the testing process, and high reliability and repeatability.

[0040] The above description is merely an embodiment of this utility model. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of this utility model, but these improvements all fall within the protection scope of this utility model.

Claims

1. A device for testing the fatigue of a flat sheet diaphragm, characterized in that, include: The test tank is used to hold the flat sheet membrane to be tested. The test tank is divided into a raw liquid chamber and a product water chamber by the membrane. The raw liquid chamber is provided with an inlet and a backwash outlet, and the product water chamber is provided with a product water outlet and a backwash inlet. The water supply system includes a raw liquid supply unit and a backwash liquid supply unit. The raw liquid supply unit is connected to the water inlet through a pipeline, and the backwash liquid supply unit is connected to the backwash inlet through a pipeline. The detection unit is used to monitor parameters during the test process, including a raw liquid chamber pressure sensor installed in the raw liquid chamber and a product water chamber pressure sensor installed in the product water chamber. The control system includes a control mechanism connected to a raw liquid supply unit, a backwash liquid supply unit, a raw liquid chamber pressure sensor, and a product water chamber pressure sensor. The control mechanism controls the raw liquid supply unit and the backwash liquid supply unit to switch flow paths based on the pressure values ​​detected by the raw liquid chamber pressure sensor and the product water chamber pressure sensor. The system repeatedly runs product water and backwash operations in the test tank to perform fatigue tests on the membrane.

2. The fatigue testing device for flat sheet membranes according to claim 1, characterized in that, The water supply system includes a water tank and an inlet pump. The water tank and the inlet pump are connected by a pipeline and connected to the inlet to form the raw liquid supply unit. The water tank and the inlet pump are connected by a pipeline and connected to the backwash inlet to form the backwash liquid supply unit. The inlet pump is connected to a control mechanism, which controls the start and stop operation of the inlet pump.

3. The fatigue testing device for flat sheet membranes according to claim 2, characterized in that, The outlet of the water inlet pump is connected to a main pipeline, which in turn connects to two branch pipelines, which are respectively connected to the water inlet and the backwash inlet. The branch pipelines connecting the water inlet and the backwash inlet are respectively equipped with a raw liquid inlet valve and a backwash inlet valve. The control mechanism is connected to the raw liquid inlet valve and the backwash inlet valve, and realizes the flow path switching by controlling the path switching state of the raw liquid inlet valve and the backwash inlet valve.

4. The flat sheet diaphragm fatigue testing device according to claim 3, characterized in that, The water inlet, backwash outlet, and water tank are connected by pipelines.

5. The fatigue testing device for flat sheet membranes according to claim 4, characterized in that, The pipelines connecting the water inlet and the backwash outlet are first connected in parallel and then merged to connect to the water tank. The parallel pipelines of the water inlet and the backwash outlet are respectively equipped with a water inlet valve and a backwash outlet valve. The control mechanism is connected to the water inlet valve and the backwash outlet valve, and the flow path is switched by controlling the flow path switching state of the water inlet valve and the backwash outlet valve.

6. The fatigue testing device for flat sheet diaphragms according to claim 5, characterized in that, The parallel pipelines of the water production port and the backwash outlet are equipped with flow meters for monitoring the instantaneous flow rate of the water production or backwash.

7. The fatigue testing device for flat sheet diaphragms according to claim 1, characterized in that, It also includes an aeration simulation system, which includes an air source, a gas flow control valve, and an aeration head installed at the bottom of the raw liquid chamber of the test tank. The control mechanism is connected to the air source and the gas flow control valve to control the start and stop of the aeration simulation system and the aeration cycle.

8. The fatigue testing device for flat sheet diaphragms according to claim 1, characterized in that, The test tank is made of transparent plastic.

9. A device for testing the fatigue of a flat sheet diaphragm, characterized in that, include: The test tank is used to hold the flat sheet membrane to be tested. The test tank is divided into a raw liquid chamber and a product water chamber by the membrane. The raw liquid chamber is provided with an inlet and a backwash outlet, and the product water chamber is provided with a product water outlet and a backwash inlet. The water supply system includes a water tank and an inlet pump. The water tank and the inlet pump are connected by pipelines and then connected to the inlet and the backwash inlet, respectively. The product water outlet, the backwash outlet and the water tank are connected by pipelines to realize water recycling. The detection unit is used to monitor parameters during the test process, including a raw liquid chamber pressure sensor installed in the raw liquid chamber, a product water chamber pressure sensor installed in the product water chamber, and a flow meter installed on the pipeline between the product water outlet, backwash outlet and water tank to monitor the instantaneous flow rate during product water or backwash. The control system includes a control mechanism and a backwash outlet valve, a product water valve, a raw liquid inlet valve, and a backwash inlet valve. These valves are connected to the backwash outlet, product water inlet, inlet, and backwash inlet, respectively, and are used to control the opening and closing of these valves. The control mechanism is connected to an inlet pump, a raw liquid chamber pressure sensor, a product water chamber pressure sensor, the backwash outlet valve, the product water valve, the raw liquid inlet valve, and a flow meter. Based on the pressure values ​​detected by the raw liquid chamber pressure sensor and the product water chamber pressure sensor, it controls the switching state of the backwash outlet valve, product water valve, raw liquid inlet valve, and backwash inlet valve, achieving flow path switching. The system automatically and repeatedly cycles through product water and backwash operations in the test tank to perform fatigue testing on the membrane. Furthermore, based on the abnormally rapid increase in instantaneous flow detected by the flow meter, it is determined that the membrane has broken due to excessive fatigue.

10. The flat sheet diaphragm fatigue testing device according to claim 9, characterized in that, It also includes an aeration simulation system, which includes an air source, a gas flow control valve, and an aeration head installed at the bottom of the raw liquid chamber of the test tank. The control mechanism is connected to the air source and the gas flow control valve to control the start and stop of the aeration simulation system and the aeration cycle. Combined with the water production and backwashing operations, it realizes the automated cyclic operation of each process of "water production-backwashing-aeration" and conducts fatigue tests on the membrane.

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