Off-line chemical cleaning device for reverse osmosis membrane

Abstract

The utility model discloses an off-line chemical cleaning device for a reverse osmosis membrane. The off-line chemical cleaning device comprises a cleaning water tank, a reverse osmosis membrane element shell, a water inlet pipeline, a water production pipeline, a concentrated water pipeline, a pressure gauge assembly, a rotor flow meter and the like. Wherein at most three reverse osmosis membrane element shells are arranged in parallel, and one reverse osmosis membrane element can be placed in each reverse osmosis membrane element shell; at most three water inlet pipelines are arranged in parallel, and each water inlet pipeline is connected with the pressure gauge assembly; at most three water production pipelines are arranged in parallel, each water production pipeline is provided with a first rotor flow meter, and the first rotor flow meters are connected with the pressure gauge assembly; at most three concentrated water pipelines are arranged in parallel, and each concentrated water pipeline is provided with a second rotor flow meter and is connected with the pressure gauge assembly. The reverse osmosis membrane off-line chemical cleaning device provided by the utility model can ensure that each reverse osmosis membrane element achieves a better cleaning effect and the cleaning effect is accurately monitored.

Description

Technical Field

[0001] This utility model relates to the field of water treatment technology, and in particular to an offline chemical cleaning device for reverse osmosis membranes. Background Technology

[0002] Currently, my country produces a large volume of wastewater daily, mainly from industrial wastewater, agricultural wastewater, and domestic sewage. Industrial wastewater is a significant source of pollution, not only due to its large volume and wide coverage, but also its complex composition, high toxicity, and difficulty in treatment. To achieve zero discharge of industrial wastewater, most industrial wastewater (especially high-salinity wastewater) utilizes membrane treatment systems in the concentration and reuse stage, primarily ultrafiltration membranes combined with reverse osmosis membranes. Reverse osmosis membranes are artificial semi-permeable membranes with specific characteristics, mimicking biological semi-permeable membranes. The principle of reverse osmosis is to apply pressure greater than the osmotic pressure of the concentrated solution, forcing water molecules to flow backward (opposite to natural osmosis) through the semi-permeable membrane into the dilute solution. Most solutes (dissolved solids) cannot pass through the semi-permeable membrane and are retained, thus achieving separation from water. The pore size of reverse osmosis membranes is extremely small, effectively removing dissolved salts, colloids, microorganisms, and organic matter from water.

[0003] However, over time, the surface of the reverse osmosis membrane is easily fouled by suspended solids, colloids, and salt scale, leading to fouling accumulation. This not only reduces the system's permeate flow and desalination rate but also increases system operating pressure, indirectly increasing operating costs. Regular cleaning can maximize the restoration of system performance. Common cleaning methods for reverse osmosis membrane fouling include online chemical cleaning and offline chemical cleaning. Online cleaning is performed directly without shutting down the system and is mainly for mild fouling and scaling. However, because it cleans membrane modules in series, it is less effective for membrane elements that have been running for a long time and have relatively heavy fouling. Offline cleaning is more thorough and requires a specialized offline cleaning device. Offline cleaning involves removing the reverse osmosis membrane elements from the membrane housing and using a dedicated offline cleaning device to clean the membrane elements in parallel. The cleaning effect is significant, and the membrane element's working capacity is more thoroughly restored after cleaning. It is suitable for treating severe fouling and scaling problems, deeply removing stubborn stains from the membrane elements and extending their service life.

[0004] Current offline reverse osmosis membrane cleaning devices have the following drawbacks:

[0005] 1. When cleaning a large number of reverse osmosis membrane elements at the same time, the cleaning agent may be biased, preferentially flowing to the path with less resistance, such as membrane elements with less fouling, resulting in uneven distribution of the cleaning agent and affecting the cleaning effect.

[0006] 2. For multiple parallel membrane element groups, it is impossible to monitor the performance of each reverse osmosis membrane element before and after cleaning, making it difficult to ensure the cleaning effect.

[0007] The statements herein provide only background information relating to this invention and do not necessarily constitute prior art. Utility Model Content

[0008] The purpose of this invention is to provide an offline chemical cleaning device for reverse osmosis membranes, which solves the problem in the prior art that when cleaning a large number of reverse osmosis membrane elements at the same time, some membrane elements have poor cleaning effect due to problems such as chemical flow deviation, and it is impossible to monitor the effect of each reverse osmosis membrane element before and after cleaning.

[0009] To achieve the above objectives, this utility model provides an offline chemical cleaning device for reverse osmosis membranes, comprising: a cleaning water tank, a reverse osmosis membrane element housing, an inlet water pipe, a product water pipe, a concentrate water pipe, a pressure gauge assembly, and a rotor flow meter.

[0010] Up to three reverse osmosis membrane element housings are connected in parallel, and each housing can hold one reverse osmosis membrane element. Up to three inlet water pipes are connected in parallel, with each pipe's end connected to the inlet of each reverse osmosis membrane element housing and its beginning connected to a cleaning water tank. Each inlet water pipe is also connected to a pressure gauge assembly via a first pressure pipe. Up to three product water pipes are connected in parallel, with each pipe's beginning connected to the product water outlet of each reverse osmosis membrane element housing and its end connected to a cleaning water tank. Water tank connection; each of the product water pipes is equipped with a first rotor flow meter, and each is connected to a pressure gauge assembly via a second pressure pipe; up to three concentrate pipes are connected in parallel, with the beginning of each concentrate pipe connected to the concentrate outlet of each reverse osmosis membrane element housing, and the end connected to a cleaning water tank; each concentrate pipe is equipped with a second rotor flow meter, and each is connected to a pressure gauge assembly via a third pressure pipe; wherein, the number of inlet water pipes, product water pipes, and concentrate pipes is consistent with the number of reverse osmosis membrane element housings.

[0011] Furthermore, the offline chemical cleaning device for the reverse osmosis membrane also includes: an inlet pump, a security filter, and a high-pressure pump.

[0012] The water inlet pump is located on the bottom side of the cleaning water tank and is connected to the input end of the security filter via a pipe; the output end of the security filter is connected to the input end of the high-pressure pump via a pipe; and the output end of the high-pressure pump is connected to the beginning of the water inlet pipe.

[0013] Furthermore, each of the water inlet pipes is equipped with a water inlet valve, and all the water inlet pipes converge into a single main water inlet pipe before passing through the water inlet valve, which is connected to the high-pressure pump.

[0014] Furthermore, each of the product water pipes is equipped with a product water valve, located between the first rotor flow meter on the product water pipe and the membrane housing of the reverse osmosis membrane element connected to the product water pipe.

[0015] Furthermore, the connection point between each of the product water pipes and the corresponding second pressure pipe is located between the product water valve on the product water pipe and the membrane housing of the reverse osmosis membrane element connected to the product water pipe. Each of the second pressure pipes is also provided with a product water pressure valve, and each product water pressure valve is located at the connection point between the second pressure pipe it is located on and the corresponding product water pipe.

[0016] Furthermore, each of the concentrate pipes is equipped with a concentrate valve, located between the second rotor flow meter on the concentrate pipe and the membrane housing of the reverse osmosis membrane element connected to the concentrate pipe.

[0017] Furthermore, the connection between each concentrate pipe and the corresponding third pressure pipe is located between the concentrate valve on the concentrate pipe and the membrane housing of the reverse osmosis membrane element connected to the concentrate pipe. Each third pressure pipe is also provided with a concentrate pressure valve, and each concentrate pressure valve is located at the connection between the third pressure pipe and the corresponding concentrate pipe.

[0018] Furthermore, the pressure gauge assembly consists of one first pressure gauge and at most three second pressure gauges. The first pressure gauge is connected to the main inlet pipe, and the number of second pressure gauges is the same as the number of concentrate pipes and product water pipes. Each second pressure gauge is connected to each concentrate pipe and each product water pipe in a corresponding manner.

[0019] Optionally, each of the water production pipelines converges into a single main water production pipeline after passing through the first rotor flow meter, and is connected to the cleaning water tank. A main water production valve is installed on this main water production pipeline. Similarly, each of the concentrate pipelines converges into a single main concentrate pipeline after passing through the second rotor flow meter, and is connected to the cleaning water tank. A main concentrate valve is installed on this main concentrate pipeline.

[0020] Optionally, the lower part of the cleaning water tank is equipped with a heating rod, and a thermometer and a pH meter are installed on the side wall. The bottom of the cleaning water tank is also equipped with a vent valve.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] 1. By setting a smaller number of reverse osmosis membrane elements to be cleaned at one time, the problem of poor cleaning effect caused by some membrane elements due to chemical flow deviation when chemically cleaning a large number of reverse osmosis membrane elements simultaneously is solved in the existing offline reverse osmosis membrane cleaning device.

[0023] 2. By installing a pressure pipe connected to a pressure gauge and a rotor flow meter on the pipe where each reverse osmosis membrane element is located, the pressure difference and flux of each membrane element can be obtained at the same time as a single test, accurately judging the cleaning effect of each membrane element. This solves the problem that the effect of each membrane element before and after cleaning cannot be observed when multiple series membrane element groups are cleaned online or multiple parallel membrane element groups are cleaned offline. Attached Figure Description

[0024] Figure 1 This is a front view of the reverse osmosis membrane offline chemical cleaning device of this utility model;

[0025] Figure 2 This is a left view of the reverse osmosis membrane offline chemical cleaning device of this utility model;

[0026] Figure 3 This is a right view of the reverse osmosis membrane offline chemical cleaning device of this utility model. Detailed Implementation

[0027] The following detailed description of the offline chemical cleaning device for reverse osmosis membranes proposed in this utility model, in conjunction with the accompanying drawings and specific embodiments, will further illustrate its advantages and features. The advantages and features of this utility model will become clearer from the following description. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, intended only to facilitate and clearly illustrate the embodiments of this utility model. Please refer to the accompanying drawings to make the objectives, features, and advantages of this utility model more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to aid those skilled in the art, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this utility model, should still fall within the scope of the technical content disclosed in this utility model.

[0028] This invention provides an offline chemical cleaning device for reverse osmosis membranes, such as... Figures 1-3 As shown, the chemical cleaning device includes: a cleaning water tank 16, an inlet pump 15, a security filter 13, a high-pressure pump 12, a reverse osmosis membrane element housing 4, an inlet water pipe 7, a product water pipe 3, a concentrate water pipe 8, a pressure gauge assembly 2, a rotor flow meter, and a series of pipeline fittings, etc.

[0029] The cleaning water tank 16 contains and holds chemical cleaning agents. The inlet pump 15 is located on the bottom side of the cleaning water tank 16 and is connected to the input end of the security filter 13 via a pipe. The inlet pump 15 pumps the chemical cleaning agents from the cleaning water tank 16 into the security filter 13. The security filter 13 filters the chemical cleaning agents, removing any large particulate contaminants that may be present. The output end of the security filter 13 is connected to the input end of the high-pressure pump 12 via a pipe. The output end of the high-pressure pump 12 is connected to the beginning of the inlet pipe 7. The high-pressure pump 12 pressurizes the filtered chemical cleaning agents and transmits them into the inlet pipe 7. Up to three reverse osmosis membrane element housings 4 are connected in parallel. During cleaning, one reverse osmosis membrane element can be placed in each reverse osmosis membrane element housing 4. Up to three inlet pipes 7 are connected in parallel to deliver pressurized chemical cleaning agents into each reverse osmosis membrane element housing 4. The end of each inlet pipe 7 is connected to the inlet of each reverse osmosis membrane element housing 4, and the beginning of each pipe is connected to the high-pressure pump 12. Up to three product water pipes 3 are connected in parallel to transport product water, which refers to pure water filtered by the reverse osmosis membrane element. The beginning of each product water pipe 3 is connected to the product water outlet of each reverse osmosis membrane element housing 4, and the end of each pipe is connected to the cleaning water tank 16. Up to three concentrate pipes 8 are connected in parallel to transport concentrate, which refers to high-concentration brine that has not permeated through the reverse osmosis membrane element. The beginning of each concentrate pipe 8 is connected to the concentrate outlet of each reverse osmosis membrane element housing 4, and the end of each concentrate pipe is connected to the cleaning water tank 16.

[0030] The system includes a maximum of three reverse osmosis membrane element housings 4, meaning that the number of reverse osmosis membrane elements cleaned in a single cycle does not exceed three. This ensures that each reverse osmosis membrane element is thoroughly and evenly cleaned, avoiding problems such as reagent flow deviation that could lead to poor cleaning results.

[0031] The number of inlet pipes 7, product water pipes 3, and concentrate pipes 8 are all the same as the number of reverse osmosis membrane element housings 4. In this preferred embodiment, the number of reverse osmosis membrane element housings 4 is set to three, and correspondingly, the number of inlet pipes 7, product water pipes 3, and concentrate pipes 8 are all set to three.

[0032] The cleaning water tank 16 is equipped with a heating rod 18 at its lower part and a thermometer 19 on its side wall. For chemical cleaning of reverse osmosis membrane elements, higher temperatures within permissible limits result in better cleaning. The heating rod 18 heats the chemical cleaning agent during preparation and after each soaking or cleaning cycle, while the thermometer 19 monitors the heating temperature to achieve optimal cleaning results. Furthermore, the cleaning water tank 16 is also equipped with a controller (not shown in the figure), which is connected to both the heating rod 18 and the thermometer 19. When the temperature value measured by the thermometer 19 is sent to the controller, the controller can automatically control the heating rod 18 to heat or stop heating based on the real-time temperature value. Alternatively, the user can manually control the heating rod 18 to heat or stop heating the agent based on the temperature value measured by the thermometer 19.

[0033] A pH meter 20 is also installed on the side wall of the cleaning water tank 16. The pH value is adjusted by adding chemicals when preparing the cleaning agent and after each soaking or cleaning. The pH meter 20 monitors the pH value to achieve a better cleaning effect.

[0034] The bottom of the cleaning water tank 16 is also equipped with a vent valve 17, which is used to drain the liquid in the cleaning water tank 16.

[0035] Each of the inlet pipes 7 is equipped with an inlet valve 6 to control the opening and closing of each inlet pipe 7, thereby enabling the independent operation of each reverse osmosis membrane element housing 4. That is, 1 to 3 reverse osmosis membrane elements can be placed at once before cleaning, or each reverse osmosis membrane element can be cleaned individually during the cleaning process according to the actual degree of fouling and the cleaning progress.

[0036] Each of the water inlet pipes 7 converges into a single main water inlet pipe before passing through the water inlet valve 6, and is connected to the high-pressure pump 12. The main water inlet pipe is also connected to the pressure gauge assembly 2 via a first pressure pipe 51, which can monitor the water inlet pressure.

[0037] Each of the product water pipes 3 is equipped with a first rotor flowmeter 91 for monitoring the product water flux. Each of the product water pipes 3 is also equipped with a product water valve 101 to control the opening and closing of each product water pipe 3. Each product water valve 101 is located between the first rotor flowmeter 91 on its product water pipe 3 and the reverse osmosis membrane element housing 4 connected to the product water pipe 3.

[0038] Each of the permeate pipes 3 is connected to the pressure gauge assembly 2 via a second pressure pipe 52, enabling monitoring of the permeate pressure of each reverse osmosis membrane element. The connection point between each permeate pipe 3 and its corresponding second pressure pipe 52 is located between the permeate valve 101 on the permeate pipe 3 and the membrane housing 4 of the reverse osmosis membrane element connected to the permeate pipe 3. Furthermore, each second pressure pipe 52 is equipped with a permeate pressure valve 111 to control the connection between each permeate pipe 3 and the pressure gauge assembly 2. Each permeate pressure valve 111 is located at the connection point between its respective second pressure pipe 52 and the corresponding permeate pipe 3. Since the permeate pressure is normally very small and almost negligible, each permeate pressure valve 111 is usually closed, only opening when needed to test for back pressure and thus detect whether the reverse osmosis membrane is damaged.

[0039] Each of the water production pipes 3 can converge into a single main water production pipe after passing through the first rotor flow meter 91, which is connected to the cleaning water tank 16. A main water production valve 21 is installed on the main water production pipe to control the opening and closing of the main water production pipe.

[0040] Each of the concentrate pipes 8 is equipped with a second rotor flow meter 92 for monitoring the concentrate flux. Each concentrate pipe 8 is also equipped with a concentrate valve 102 to control the opening and closing of each concentrate pipe 8. Each concentrate valve 102 is located between the second rotor flow meter 92 on its respective concentrate pipe 8 and the reverse osmosis membrane element housing 4 connected to the concentrate pipe 8.

[0041] Each of the concentrate pipes 8 is connected to the pressure gauge assembly 2 via a third pressure pipe 53, enabling monitoring of the concentrate pressure of each reverse osmosis membrane element. The connection point between each concentrate pipe 8 and its corresponding third pressure pipe 53 is located between the concentrate valve 102 on the concentrate pipe 8 and the membrane housing 4 of the reverse osmosis membrane element connected to the concentrate pipe 8. Furthermore, each third pressure pipe 53 is equipped with a concentrate pressure valve 112 to control the connection between each concentrate pipe 8 and the pressure gauge assembly 2. Each concentrate valve 112 is located at the connection point between its respective third pressure pipe 53 and the corresponding concentrate pipe 8. When water flows into the reverse osmosis membrane element from the feed pipe 6, the flow is resisted, causing the water pressure to gradually decrease along the flow direction. Therefore, the concentrate pressure is lower than the feed pressure. Since contaminants accumulated on the membrane surface are the main source of resistance, the difference between the feed pressure and the concentrate pressure is an important indicator for measuring the degree of membrane element fouling.

[0042] Each of the concentrated water pipes 8 can converge into a single concentrated water main pipe after passing through the second rotor flow meter 92, which is connected to the cleaning water tank 16. A concentrated water main valve 14 is installed on the concentrated water main pipe to control the opening and closing of the concentrated water main pipe.

[0043] The pressure gauge assembly 2 is housed in the control cabinet 1. The pressure gauge assembly 2 consists of one first pressure gauge and at most three second pressure gauges. The first pressure gauge is connected to the main inlet water pipe to detect the inlet water pressure. The number of second pressure gauges corresponds to the number of concentrate pipes 8 and product water pipes 3. Each second pressure gauge is connected to each concentrate pipe 8 and each product water pipe 3 in a one-to-one correspondence (i.e., one second pressure gauge is simultaneously connected to one concentrate pipe 8 and one product water pipe 3), used to detect the concentrate or product water pressure of each reverse osmosis membrane element. Specifically, when the product water pressure valve 111 is closed and the concentrate water pressure valve 112 is open, each second pressure gauge detects the concentrate pressure of each reverse osmosis membrane element, and as described above, the first pressure gauge detects the inlet water pressure at this time. When the product water pressure valve 111 is open and the concentrate water pressure valve 112 is closed, each second pressure gauge detects the product water pressure of each reverse osmosis membrane element, and as described above, the first pressure gauge detects the inlet water pressure at this time.

[0044] In this preferred embodiment, since the number of reverse osmosis membrane element housings 4 is set to three, the corresponding number of product water pipes 3 and concentrate pipes 8 is also set to three. Therefore, the number of the second pressure gauges is also set to three.

[0045] The inlet and the product water outlet are located on the same side of the reverse osmosis membrane element housing 4, while the concentrate outlet is located on the other side of the reverse osmosis membrane element housing 4.

[0046] When cleaning reverse osmosis membrane elements using the offline chemical cleaning apparatus of this preferred embodiment, the main steps include:

[0047] S1. Place each reverse osmosis membrane element to be cleaned into each reverse osmosis membrane element housing 4. One to three elements can be placed at a time. In this embodiment, three elements are selected. Therefore, the specific cleaning method and steps will be described using this embodiment. Open the three concentrate pressure valves 112 to connect the three concentrate pipes 8 to the second pressure gauges. Therefore, during the entire cleaning and testing process, the first pressure gauge detects the inlet water pressure, and the three second pressure gauges detect the concentrate pressure of the three reverse osmosis membrane elements respectively. Open the permeate main valve 21 and the concentrate main valve 14.

[0048] S2. Pour clean water into the cleaning water tank 16, open all inlet valves 6, product water valve 101 and concentrate valve 102, turn on inlet pump 15 and high pressure pump 12, and the clean water is pumped into the security filter 13. After being pressurized by the high pressure pump 12, it enters each reverse osmosis membrane element through the inlet pipe 7. The water filtered by the reverse osmosis membrane element is sent back to the cleaning water tank 16 as product water through the product water pipe 3. The water that does not pass through the reverse osmosis membrane element is sent back to the cleaning water tank 16 as concentrate through the concentrate pipe 8. During this process, observe the values ​​of the three first rotor flow meters 91 and the three second rotor flow meters 92, record the product water flux and concentrate flux of the three reverse osmosis membrane elements before cleaning, and observe the values ​​of the pressure gauge assembly 2 (including the first pressure gauge and the three second pressure gauges) at the same time. Record the inlet water pressure and concentrate pressure of the three reverse osmosis membrane elements before cleaning, and calculate the difference between the inlet water pressure and concentrate pressure of each reverse osmosis membrane element to evaluate the subsequent cleaning effect.

[0049] S3. Turn off the inlet pump 15 and the high-pressure pump 12, prepare the chemical cleaning agent in the cleaning water tank 16, heat the chemical cleaning agent with the heating rod 18, monitor the temperature with the thermometer 19 until the appropriate temperature is reached, monitor the pH value of the chemical cleaning agent with the pH meter 20, and add chemical agent if necessary to reach the required pH value.

[0050] S4. Perform a circulating cleaning of the reverse osmosis membrane elements, mainly including the following steps:

[0051] S4.1 Simultaneously open all inlet valves 6, close all product water valves 101, and open all concentrate valves 102;

[0052] S4.2. Start the inlet pump 15 and the high-pressure pump 12. The chemical cleaning agent is pumped into the security filter 13 and filtered out any large particulate contaminants that may be present to prevent secondary contamination of the reverse osmosis membrane element. Then, driven by the high-pressure pump 12, it enters the reverse osmosis membrane element through the inlet pipe 7. Since the product water pipe 3 is closed, all the chemical cleaning agent flows from the inlet side to the concentrate side. During this process, it comes into full contact with the surface of the reverse osmosis membrane and washes away the contaminants on the surface of the reverse osmosis membrane. The chemical cleaning agent that does not pass through the reverse osmosis membrane returns to the cleaning water tank 16 through the concentrate pipe 8 and is then pumped back into the security filter 13, thus forming a cycle between the inlet side → reverse osmosis membrane element → concentrate side → cleaning water tank 16.

[0053] S4.3 During the circulating cleaning process, observe the value of the second rotor flow meter 92 and record the concentrate flux. At this time, the concentrate flux is equal to the feed water flux. At the same time, observe the value of the first pressure gauge and record the feed water pressure. This can ensure that the flow rate and pressure of the chemical cleaning agent flowing into each reverse osmosis membrane element are stable during each circulating cleaning process.

[0054] S4.4 As the cycle cleaning time increases, more and more contaminants will appear in the chemical cleaning agent. The pH value of the chemical cleaning agent will be monitored by pH meter 20. If the pH value changes, the agent will be replenished in time. If too many contaminants are observed in the chemical cleaning agent, the inlet pump 15 and the high-pressure pump 12 can be turned off, the vent valve 17 can be opened, the liquid in the cleaning water tank 16 and the pipeline can be drained, and the chemical cleaning agent can be prepared again.

[0055] S5. If necessary, soak the reverse osmosis membrane element, turn off the feed water pump 15 and the high pressure pump 12, close all product water valves 101 and all concentrate valves 102, and let the chemical cleaning agent statically soak the reverse osmosis membrane element so that the chemical cleaning agent can fully penetrate into the deep pollutants and dissolve stubborn deposits. The soaking time is generally 2 hours.

[0056] S6. If necessary, restart the inlet pump 15 and the high-pressure pump 12, and open all the concentrate valves 102 to perform a second circulation cleaning, so as to completely remove the pollutants loosened during the soaking process from the reverse osmosis membrane element. S4 and S5 can be performed alternately as needed until the required cleaning effect is achieved.

[0057] S7. The cleaning effect of the reverse osmosis membrane element is tested, mainly including the following steps:

[0058] S7.1 Open the vent valve 17 to drain all the chemical cleaning agent in the cleaning water tank 16 and the pipeline, and replace the chemical cleaning agent with clean water;

[0059] S7.2 Open all inlet valves 6, product water valve 101 and concentrate valve 102, turn on inlet pump 15 and high pressure pump 12, clean water is pumped into security filter 13, and after being pressurized by high pressure pump 12, it enters the reverse osmosis membrane element through inlet pipe 7. The product water filtered by the reverse osmosis membrane element is sent back to the cleaning water tank 16 through product water pipe 3, and the concentrate water that does not pass through the reverse osmosis membrane element is sent back to the cleaning water tank 16 through concentrate water pipe 8.

[0060] S7.3 Observe the values ​​of the three first rotor flow meters 91 and record the permeate flux of the three reverse osmosis membrane elements after cleaning. If the permeate flux after cleaning is significantly increased compared with the permeate flux before cleaning, or reaches the designed membrane flux, it indicates that a good cleaning effect has been achieved.

[0061] S7.4 Observe the values ​​of the three second rotor flow meters 92, and record the concentrate flux of the three reverse osmosis membrane elements after cleaning. The sum of the permeate flux and concentrate flux of each reverse osmosis membrane element is the feed flux of that reverse osmosis membrane element. The ratio of the permeate flux to the feed flux of each reverse osmosis membrane element is the recovery rate of that reverse osmosis membrane element. If the recovery rate after cleaning is significantly improved compared with the recovery rate before cleaning, it indicates that a good cleaning effect has been achieved.

[0062] S7.5 Observe the value of pressure gauge component 2, record the feed water pressure and concentrate pressure of the three reverse osmosis membrane elements after cleaning, calculate the difference between the feed water pressure and concentrate pressure of each reverse osmosis membrane element. If the pressure difference is smaller than the pressure difference before cleaning, it means that the resistance to water flow has decreased, the pollutants accumulated on the surface of the reverse osmosis membrane have decreased, and a better cleaning effect has been achieved.

[0063] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0064] In the description of this utility model, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0065] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0066] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0067] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above content. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. An offline chemical cleaning device for reverse osmosis membranes, characterized in that, include: Cleaning water tank (16), reverse osmosis membrane element housing (4), inlet water pipe (7), product water pipe (3), concentrate water pipe (8), pressure gauge assembly (2), rotor flow meter; Up to three reverse osmosis membrane element housings (4) are arranged in parallel, and one reverse osmosis membrane element can be placed in each reverse osmosis membrane element housing (4); The water inlet pipes (7) are arranged in parallel in up to three. The end of each water inlet pipe (7) is connected to the water inlet of each reverse osmosis membrane element housing (4), and the beginning of each water inlet pipe (7) is connected to the cleaning water tank (16). Each water inlet pipe (7) is also connected to the pressure gauge assembly (2) through the first pressure pipe (51). The water production pipes (3) are arranged in parallel in up to three. The beginning of each water production pipe (3) is connected to the water production outlet of each reverse osmosis membrane element housing (4), and the end of each pipe is connected to the cleaning water tank (16). Each water production pipe (3) is equipped with a first rotor flow meter (91) and is connected to the pressure gauge assembly (2) through a second pressure pipe (52). Up to three of the concentrate pipes (8) are connected in parallel. The beginning of each concentrate pipe (8) is connected to the concentrate outlet of each reverse osmosis membrane element housing (4), and the end is connected to the cleaning water tank (16). Each concentrate pipe (8) is equipped with a second rotor flow meter (92), and each is connected to the pressure gauge assembly (2) through a third pressure pipe (53). The number of the inlet pipe (7), product water pipe (3) and concentrate pipe (8) is the same as the number of reverse osmosis membrane element housings (4).

2. The offline chemical cleaning device for reverse osmosis membranes as described in claim 1, characterized in that, The offline chemical cleaning device for the reverse osmosis membrane also includes: a water inlet pump (15), a security filter (13), and a high-pressure pump (12). The water inlet pump (15) is located on the bottom side of the cleaning water tank (16) and is connected to the input end of the security filter (13) through a pipe; the output end of the security filter (13) is connected to the input end of the high pressure pump (12) through a pipe; and the output end of the high pressure pump (12) is connected to the beginning of the water inlet pipe (7).

3. The offline chemical cleaning device for reverse osmosis membranes as described in claim 1 or 2, characterized in that, Each of the water inlet pipes (7) is equipped with a water inlet valve (6), and the water inlet pipes (7) converge into the same main water inlet pipe before passing through the water inlet valve (6), which is connected to the high-pressure pump (12).

4. The offline chemical cleaning device for reverse osmosis membranes as described in claim 3, characterized in that, Each of the product water pipes (3) is provided with a product water valve (101), located between the first rotor flow meter (91) on the product water pipe (3) and the reverse osmosis membrane element housing (4) connected to the product water pipe (3).

5. The offline chemical cleaning device for reverse osmosis membranes as described in claim 4, characterized in that, The connection between each of the product water pipes (3) and the corresponding second pressure pipe (52) is located between the product water valve (101) on the product water pipe (3) and the reverse osmosis membrane element housing (4) connected to the product water pipe (3). Each of the second pressure pipes (52) is also provided with a product water pressure valve (111), and each product water pressure valve (111) is located at the connection between the second pressure pipe (52) it is located on and the corresponding product water pipe (3).

6. The offline chemical cleaning device for reverse osmosis membranes as described in claim 5, characterized in that, Each of the concentrate pipes (8) is provided with a concentrate valve (102), located between the second rotor flow meter (92) on the concentrate pipe (8) and the reverse osmosis membrane element housing (4) connected to the concentrate pipe (8).

7. The reverse osmosis membrane offline chemical cleaning device as described in claim 6, characterized in that, The connection between each of the concentrate pipes (8) and the corresponding third pressure pipe (53) is located between the concentrate valve (102) on the concentrate pipe (8) and the membrane housing (4) of the reverse osmosis membrane element connected to the concentrate pipe (8). Each of the third pressure pipes (53) is also provided with a concentrate pressure valve (112), and each concentrate pressure valve (112) is located at the connection between the third pressure pipe (53) and the corresponding concentrate pipe (8).

8. The offline chemical cleaning device for reverse osmosis membranes as described in claim 7, characterized in that, The pressure gauge assembly (2) is divided into one first pressure gauge and at most three second pressure gauges. The first pressure gauge is connected to the main inlet pipe. The number of the second pressure gauges is the same as the number of the concentrate pipe (8) and the product water pipe (3). Each second pressure gauge is connected to each concentrate pipe (8) in a one-to-one correspondence, and is also connected to each product water pipe (3) in a one-to-one correspondence.

9. The offline chemical cleaning device for reverse osmosis membranes as described in claim 1 or 2, characterized in that, Each of the water production pipes (3) converges into a single main water production pipe after passing through the first rotor flow meter (91), and is connected to the cleaning water tank (16). A main water production valve (21) is installed on the main water production pipe. Each of the concentrated water pipes (8) converges into a single main concentrated water pipe after passing through the second rotor flow meter (92), and is connected to the cleaning water tank (16). A main concentrated water valve (14) is installed on the main concentrated water pipe.

10. The reverse osmosis membrane offline chemical cleaning device as described in claim 1 or 2, characterized in that, The cleaning water tank (16) is equipped with a heating rod (18) at the bottom and a thermometer (19) and a pH meter (20) on the side wall. The bottom of the cleaning water tank (16) is also equipped with a vent valve (17).

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