Seawater desalination control system

Abstract

The invention discloses a seawater desalination control system, and belongs to the technical field of resource conversion, the system can comprise a filtering device, a first end of the filtering device is used for connecting a seawater input port of the system, and the seawater input port is used for introducing seawater to be treated; the first end of the first reverse osmosis device is connected with the second end of the filtering device; the first end of the second reverse osmosis device is connected with the second end of the first reverse osmosis device, the first end of the second reverse osmosis device is used for being connected with a fresh water connector of the system, the fresh water connector is used for introducing unpurified fresh water, and the second end of the second reverse osmosis device is used for being connected with a fresh water output port of the system; the third end of the second reverse osmosis device is connected with the first end of the first reverse osmosis device and the first end of the second reverse osmosis device. The system can improve the water production efficiency of equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of resource conversion, and more specifically, to a reverse osmosis seawater desalination control system. Background Art

[0002] Reverse osmosis desalination refers to the technology of producing fresh water by desalinating seawater. It is an open-source incremental technology for realizing the utilization of water resources. Existing reverse osmosis desalination devices can use reverse osmosis membranes to filter out impurities and salt in seawater and desalinate seawater, but they are not suitable for changing working conditions, produce single-quality fresh water, and have high energy consumption. If the working conditions change and the output changes, its control system is difficult to adaptively control the normal operation of the reverse osmosis desalination device. In the actual application scenario, there should be a reverse osmosis desalination device that has the ability to output fresh water of various qualities from seawater desalination and re-purify external fresh water. Summary of the invention

[0003] One object of the present invention is to provide a new technical solution for a seawater desalination control system.

[0004] According to the present invention, a reverse osmosis seawater desalination control system is provided, the system comprising: A filtering device, wherein a first end of the filtering device is used to connect to a seawater inlet of the system, and the seawater inlet is used to introduce seawater to be treated; a first reverse osmosis device, wherein a first end of the first reverse osmosis device is connected to a second end of the filtering device; a second reverse osmosis device, wherein the first end of the second reverse osmosis device is connected to the second end of the first reverse osmosis device, the first end of the second reverse osmosis device is used to connect to the fresh water interface of the system, the fresh water interface is used to introduce unpurified fresh water, the second end of the second reverse osmosis device is used to connect to the fresh water output port of the system, and the third end of the second reverse osmosis device is connected to the first end of the first reverse osmosis device and the first end of the second reverse osmosis device; Wherein, the system includes a first fresh water production mode, a second fresh water production mode and a fresh water purification mode; When the system is in the first fresh water production mode, the filtering device filters the seawater to be treated transported from the seawater input port of the system to obtain and output filtered seawater to the first reverse osmosis device, and the first reverse osmosis device performs reverse osmosis purification on the filtered seawater to obtain and output reverse osmosis filtered fresh water to the fresh water interface of the system, and outputs it from the fresh water interface of the system; When the system is in the second fresh water output mode, the filtering device filters the seawater to be treated transported from the seawater inlet of the system to obtain and output filtered seawater to the first reverse osmosis device, the first reverse osmosis device performs reverse osmosis purification on the filtered seawater to obtain and output reverse osmosis purified fresh water to the second reverse osmosis device, the second reverse osmosis device performs reverse osmosis purification on the fresh water after reverse osmosis purification in the first reverse osmosis device again, and outputs the purified high-purity fresh water from the fresh water output port of the system; When the system is in the fresh water purification mode, exogenous fresh water with relatively high salt content is connected from the fresh water interface of the system, transported to the second reverse osmosis device for reverse osmosis purification, and the purified high-purity fresh water is output from the fresh water output port of the system.

[0005] Optionally, the filtering device includes a control valve, a first pressure gauge, a seawater pump, a flow control valve, a first pressure transmitter, a filter, a multi-way valve, a fine filter and a safety filter; Wherein, the first end of the water inlet control valve serves as the first end of the filtering device, the second end of the water inlet control valve is connected to the first end of the seawater pump, the second end of the seawater pump is connected to the first end of the flow control valve, the second end of the flow control valve is connected to the first end of the multi-way valve, the second end of the multi-way valve is connected to the first end of the filter, the second end of the filter is connected to the third end of the multi-way valve, the fourth end of the multi-way valve is connected to the first end of the fine filter, the second end of the fine filter is connected to the first end of the safety filter, and the second end of the safety filter serves as the second end of the filtering device; Wherein, the first pressure gauge is used to detect and display the water pressure at the first end of the seawater pump, and the first pressure transmitter is used to detect the water pressure at the second end of the seawater pump valve.

[0006] Optionally, the system further comprises a first discharge valve, a second discharge valve and a third discharge valve; The second end of the filter is connected to the first end of the first discharge valve, the connection point between the second end of the first discharge valve and the fifth end of the multi-way valve is connected to the concentrated water output port of the system, the third end of the fine filter is connected to the first end of the second discharge valve, the third end of the safety filter is connected to the first end of the third discharge valve, and the connection point between the second end of the second discharge valve and the second end of the third discharge valve is connected to the concentrated water output port of the system.

[0007] Optionally, the first reverse osmosis device includes a second pressure transmitter, a primary high-pressure pump, a first check valve, a second pressure gauge, a first reverse osmosis membrane group, a first salinity meter, a first flow meter, a third pressure gauge and a first switch valve; The first end of the primary high-pressure pump serves as the first end of the first reverse osmosis device, the second end of the primary high-pressure pump is connected to the first end of the first check valve, the second end of the first check valve is connected to the first end of the first reverse osmosis membrane group, the second end of the first reverse osmosis membrane group is connected to the first end of the first switch valve, and the second end of the first switch valve serves as the second end of the first reverse osmosis device; The second pressure transmitter is used to detect the water pressure at the first end of the first-stage high-pressure pump, and cooperates with the first pressure transmitter to detect and compare the pressure difference between the fine filter and the safety filter, and detect the water pressure at the first end of the first reverse osmosis membrane group. The first salinometer is used to detect the salt content at the second end of the first reverse osmosis device. The first flow meter is used to detect the flow at the second end of the first reverse osmosis membrane group. The third pressure gauge is used to detect and display the water pressure at the second end of the first reverse osmosis membrane group.

[0008] Optionally, the first reverse osmosis device includes a second check valve, a third check valve, a second switch valve, and a third switch valve; Wherein, the second end of the second check valve is connected to the first end of the primary high-pressure pump, the first end of the second check valve is connected to the second end of the second switch valve, the first end of the second switch valve is connected to the first end of the first switch valve, the first end of the third switch valve is connected to the first end of the first switch valve, the second end of the third switch valve is connected to the first end of the third check valve, and the second end of the third check valve is connected to the concentrated water output port of the system; When the produced water of the first reverse osmosis device is detected by the first salinity meter and is determined to exceed the set requirements, the second switch valve is opened and the produced water is introduced into the first end (inlet) of the first reverse osmosis device through the second check valve to be recycled. The part that cannot be recycled by the first reverse osmosis device is discharged to the outside of the system through the concentrated water output port through the third switch valve and the third check valve.

[0009] Optionally, the first reverse osmosis device further includes a third pressure transmitter, a first regulating valve and a fourth check valve; Wherein, the third end of the first reverse osmosis membrane group is connected to the first end of the first regulating valve, the second end of the first regulating valve is connected to the first end of the fourth check valve, and the second end of the fourth check valve is connected to the concentrated water output port of the system; The third pressure transmitter is used to detect the water pressure at the third end of the first reverse osmosis membrane group, and compare the pressure difference at the second end of the first-stage high-pressure pump with the second pressure transmitter; when the system starts to run, the first regulating valve opens to discharge the gas in the system, and when the system is running, the working pressure of the first reverse osmosis membrane group is adjusted, and the first reverse osmosis membrane group is maintained to work within the required control pressure range, and the system is closed when it stops running.

[0010] Optionally, the second reverse osmosis device includes a fourth pressure transmitter, a secondary high-pressure pump, a fifth pressure transmitter, a fourth switch valve, a second reverse osmosis membrane group, a second flow meter, a second salinity meter and a fifth switch valve; Wherein, the first end of the secondary high-pressure pump serves as the first end of the second reverse osmosis device, the second end of the secondary high-pressure pump is connected to the first end of the fourth switch valve, the second end of the fourth switch valve is connected to the first end of the second reverse osmosis membrane group, the second end of the second reverse osmosis membrane group is connected to the first end of the fifth switch valve, the second end of the fifth switch valve is connected to the concentrated water output port of the system, the third end of the second reverse osmosis membrane group is connected to the second end of the second regulating valve, and the first end of the second regulating valve is connected to the first end of the secondary high-pressure pump; The fourth pressure transmitter is used to detect the water pressure at the first end of the secondary high-pressure pump, the fifth pressure transmitter is used to detect the water pressure at the second end of the secondary high-pressure pump, the second flow meter is used to detect the flow at the second end of the second reverse osmosis membrane group, and the second salinity meter is used to detect the salt content at the second end of the second reverse osmosis membrane group.

[0011] Optionally, the second reverse osmosis device further includes a sixth pressure transmitter, a second regulating valve, a third regulating valve, a third flow meter, and a fifth check valve; Wherein, the third end of the second reverse osmosis membrane group is connected to the first end of the second regulating valve, the second end of the second regulating valve is connected to the first end of the secondary high-pressure pump, the first end of the third regulating valve is connected to the third end of the second reverse osmosis membrane group, the second end of the third regulating valve is connected to the first end of the third flow meter, the second end of the third flow meter is connected to the first end of the fifth check valve, and the second end of the fifth check valve is connected to the second end of the filtering device; The sixth pressure transmitter is used to detect the water pressure at the third end of the second reverse osmosis membrane group, the third flowmeter is used to detect the flow at the third end of the third regulating valve, the third regulating valve regulates the flow through the fifth check valve, and the second regulating valve regulates the water pressure at the third end of the second reverse osmosis device.

[0012] Optionally, the system further comprises a sixth check valve; Wherein, the first end of the sixth check valve is connected to the third end of the fifth switch valve, and the second end of the sixth check valve is connected to the concentrated water output port of the system.

[0013] The produced water of the second reverse osmosis membrane group exceeding the set requirement is discharged to the concentrated water output port in one direction through the third end of the fifth switch valve and the sixth check valve.

[0014] Optionally, the system further comprises an eighth switch valve and a fourth pressure gauge; Wherein, the eighth switch valve is connected between the first end of the second reverse osmosis device and the fresh water interface of the system; Among them, the fourth pressure gauge detects and displays the water pressure of the fresh water output by the first reverse osmosis device at the first end of the secondary high-pressure pump, displays the water pressure of the fresh water output by the first reverse osmosis device before passing through the fresh water interface, and displays the water pressure of the fresh water input from the external source before entering the first end of the secondary high-pressure pump.

[0015] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0017] Figure 1 It is a structural diagram of a seawater desalination control system according to an embodiment of the present application. DETAILED DESCRIPTION

[0018] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0019] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0020] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0021] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0022] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0023] According to a seawater desalination control system provided by the present application, Figure 1 As shown, the system includes: A filtering device, wherein the first end of the filtering device is used to connect to the seawater input port A of the system, and the seawater input port A is used to introduce the seawater to be treated; a first reverse osmosis device, wherein the first end of the first reverse osmosis device is connected to the second end of the filtering device, the second end of the first reverse osmosis device is connected to the first end of the second reverse osmosis device, connected to the concentrated water output port (port C), connected to the first end of the first reverse osmosis device, and the third end of the first reverse osmosis device is connected to the concentrated water output port (port C); A second reverse osmosis device, the first end of the second reverse osmosis device is connected to the second end of the first reverse osmosis device, the second end of the second reverse osmosis device is connected to the fresh water output port (D port) of the system, the third end of the second reverse osmosis device is connected to the first end of the second reverse osmosis device, and is connected to the first end of the first reverse osmosis device.

[0024] An eighth switch valve is connected to the first end of the second reverse osmosis device (the second end outlet of the second reverse osmosis device) to form a fresh water interface (G port) of the system; In the first fresh water production mode, the filtering device filters the untreated seawater output from the seawater input port (port A) of the system, and outputs the filtered seawater to the first reverse osmosis device. The first reverse osmosis device performs reverse osmosis purification on the filtered seawater, and the produced water (fresh water for domestic use with a certain salinity) is output from the fresh water interface (port G); In the second fresh water output mode, the filtering device filters the seawater to be treated output from the seawater input port A of the system, and outputs the filtered seawater to the first reverse osmosis device. The fresh water filtered by the first reverse osmosis device is subjected to reverse osmosis purification again by the second reverse osmosis device, and the purified high-purity fresh water is output from the fresh water output port (port D) of the system. In the fresh water purification mode, exogenous unpurified fresh water (turbidity ≤ 5 NTU, salt content (TDS) ≤ 500ppm) is input into the system through the fresh water interface (G port), and is subjected to reverse osmosis purification treatment through the second reverse osmosis device. The purified water is then obtained to obtain high-purity fresh water, which is then output from the system's fresh water output port (D port).

[0025] In the present application, the filtering device can pre-treat the seawater and intercept some large particles of impurities by physical means to provide relatively clean seawater.

[0026] In the present application, the first reverse osmosis device can remove impurities and salts in the filtered seawater to output purified fresh water with a TDS value lower than the set TDS value. For example, when the TDS value is set to 400ppm, the output water TDS value is lower than 400ppm.

[0027] In the present application, the second reverse osmosis device can further remove the salt in the produced water output by the first reverse osmosis device, thereby outputting high-purity fresh water below the set TDS value, for example: the produced water TDS set value is 40ppm, and the output produced water TDS value is in the range of 2ppm to 40ppm.

[0028] In the present application, the unpurified fresh water input from an external source is subjected to reverse osmosis purification treatment through a second reverse osmosis device to reduce the salt content in the external fresh water and achieve output of fresh water that meets the requirements of high purity, for example: the set value of the produced water TDS is 40ppm, and the output produced water TDS value is within the range of 2ppm to 40ppm.

[0029] In other words, the seawater desalination control system can filter and purify seawater through the filtering device and the first reverse osmosis device, and the purified fresh water can be output to the outside of the system for users to use; the purified fresh water is subjected to secondary purification treatment by the second reverse osmosis device and output to the outside of the system for users to use; the unpurified fresh water input from the external source (for example: commercial tap water, etc.) is purified by the second reverse osmosis device to obtain high-purity fresh water, which is output to the outside of the system for users to use.

[0030] The new seawater desalination control system has the ability to output fresh water of various qualities and re-purify external fresh water under variable operating conditions, thereby improving water production efficiency.

[0031] In some embodiments, the filtering device includes a water inlet control valve V101, a first pressure gauge PI101, a seawater pump 15, a flow control valve V1, a first pressure transmitter PIT201, a filter 11, a multi-way valve 12, a fine filter 13 and a safety filter 14; Wherein, the first end of the water inlet control valve V101 serves as the first end of the filtering device, the second end of the water inlet control valve V101 is connected to the first end of the seawater pump 15, the second end of the seawater pump 15 is connected to the first end of the flow control valve V1, the second end of the flow control valve V1 is connected to the first end of the multi-way valve 12, the second end of the multi-way valve 12 is connected to the first end of the filter 11, the second end of the filter 11 is connected to the third end of the multi-way valve 12, the fourth end of the multi-way valve 12 is connected to the first end of the fine filter 13, the second end of the fine filter 13 is connected to the first end of the safety filter 14, and the second end of the safety filter 14 serves as the second end of the filtering device; The first pressure gauge PI101 is used to detect and display the water pressure at the first end of the seawater pump 15, and the first pressure transmitter PIT201 is used to detect the water pressure at the second end of the flow control valve V1.

[0032] In the present application, the water inlet control valve V101 is used to adjust the flow rate of seawater entering the seawater pump 15 .

[0033] In the present application, the first pressure gauge PI101 can directly display the water pressure entering the first end of the seawater pump 15 .

[0034] In the present application, the seawater pump 15 can be started when the first pressure gauge PI101 shows that the water pressure is greater than 0.05 MPa.

[0035] In the present application, after the seawater desalination equipment is started, when the first pressure transmitter PIT201 detects that the water pressure rises to 0.3MPa, the system can enter the fresh water production mode.

[0036] In the present application, the filter 11 can pre-treat the seawater to remove large particles, suspended solids, algae, microorganisms and other impurities therein. The filter 11 uses a physical filtration and screening mechanism, such as using sand, gravel, activated carbon, a specific filter membrane or net, etc., to achieve preliminary purification of the seawater to be treated.

[0037] In the present application, the multi-way valve 12 can deliver the seawater to be treated to the filter 11 and deliver the seawater treated by the filter 11 to the fine filter 13 .

[0038] In the present application, the fine filter 13 is used to further remove tiny particles and impurities in the seawater.

[0039] In the present application, the security filter 14 usually adopts high-precision filtering materials, such as ultrafiltration membrane or nanofiltration membrane, to remove impurities such as tiny particles, colloids, microorganisms and organic matter remaining in the seawater.

[0040] In other words, by providing a filtering device, effective filtering treatment of the seawater to be treated can be achieved.

[0041] In some embodiments, the system also includes a first discharge valve V3, a second discharge valve V4 and a third discharge valve V6, the second end of the filter 11 is connected to the first end of the first discharge valve V3, the connection point between the second end of the first discharge valve V3 and the fifth end of the multi-way valve 12 is connected to the concentrated water discharge pipe of the system, and the concentrated water is discharged from the concentrated water output port C, the third end of the fine filter 13 is connected to the first end of the second discharge valve V4, the third end of the safety filter 14 is connected to the first end of the third discharge valve V6, the second end of the second discharge valve V4 and the second end of the third discharge valve V6 are connected to the concentrated water discharge pipe, and the concentrated water is discharged from the concentrated water output port C.

[0042] In the present application, the first discharge valve V3 is used to discharge seawater, and controls the seawater in the filter 11 to be discharged from the concentrated water output port C of the system.

[0043] In the present application, the second discharge valve V4 and the third discharge valve V6 are used to discharge the seawater containing the filtered interceptions in the fine filter 13 and the security filter 14, respectively, and discharge them from the concentrated water output port C of the system.

[0044] In other words, the first discharge valve V3, the second discharge valve V4 and the third discharge valve V6 are respectively arranged at the lower parts of the filter 11, the fine filter 13 and the safety filter 14, so that the filtered retaining materials in the filter can be discharged, thereby improving the reliability and stability of the filter operation and ensuring that the quality of seawater input to the first reverse osmosis device is within the range required by the system.

[0045] In some examples, the system also includes a fourth drain valve V2, a fifth drain valve V5 and a sixth drain valve V7, the fourth drain valve V2 is used to discharge the gas in the filter 11, the fifth drain valve V5 is used to discharge the gas in the fine filter 13, and the sixth drain valve V7 is used to discharge the gas in the safety filter 14.

[0046] In other words, the fourth discharge valve V2, the fifth discharge valve V5 and the sixth discharge valve V7 provided on the upper part of the filter 11, the fine filter 13 and the safety filter 14 can remove the residual gas in the system to ensure that the system can work reliably and stably.

[0047] In some embodiments, the first reverse osmosis device includes a second pressure transmitter PIT202, a primary high-pressure pump 21, a first check valve Vz1, a second pressure gauge PI301, a first reverse osmosis membrane group 22, a first salinity meter SIS301, a first flow meter FIT301, a third pressure gauge PI306 and a first switch valve MV2; The first end of the primary high-pressure pump 21 serves as the first end of the first reverse osmosis device, the second end of the primary high-pressure pump 21 is connected to the first end of the first check valve Vz1, the second end of the first check valve Vz1 is connected to the first end of the first reverse osmosis membrane group 22, the second end of the first reverse osmosis membrane group 22 is connected to the first end of the first switch valve MV2, and the second end of the first switch valve MV2 serves as the second end of the first reverse osmosis device; Among them, the second pressure transmitter PIT202 is used to detect the water pressure at the first end of the first-stage high-pressure pump 21, the second pressure gauge PI301 is used to detect and display the water pressure at the first end of the first reverse osmosis membrane group 22, the first salinity meter SIS301 is used to detect the salt content (TDS value) at the second end of the first reverse osmosis membrane group 22, the first flow meter FIT301 is used to detect the flow rate at the second end of the first reverse osmosis membrane group 22, and the third pressure gauge PI306 is used to detect and display the water pressure at the second end of the first reverse osmosis membrane group 22.

[0048] In the present application, when the system is in the first fresh water production mode or the second fresh water production mode, the second pressure transmitter PIT202 detects that the water pressure at the second end of the flow control valve V1 is lower than the limit of 0.1 MPa, increases the opening of the flow control valve V1, starts the seawater pump to increase the pressure, and maintains the water pressure at the first end of the subsequent first-stage high-pressure pump 21 within the range of 0.05 MPa to 0.2 MPa.

[0049] In this application, when the system is in the first fresh water production mode or the second fresh water production mode, 3 minutes after the first-level high-pressure pump 21 is started, the water pressure at the second pressure transmitter PIT202 is higher than 0.05MPa, and the first-level high-pressure pump 21 is in normal operation. When the water inlet pressure of the first-level high-pressure pump 21 is lower than the required value after operation, it is adjusted through the flow control valve V1; when the water inlet pressure of the first-level high-pressure pump 21 is lower than 0.05MPa, the system automatically issues an audible and visual alarm, and when the water inlet pressure of the first-level high-pressure pump 21 is lower than 0.02MPa, or reaches the rated working pressure of the first-level high-pressure pump 21, or reaches the protection alarm value set by the system (for example: 6.5MPa), the system automatically shuts down and issues an audible and visual alarm.

[0050] In the present application, the first reverse osmosis membrane group 22 may include a reverse osmosis membrane 1A, a reverse osmosis membrane 1B and a reverse osmosis membrane 1C, the connection point of the first end of the reverse osmosis membrane 1A and the first end of the reverse osmosis membrane 1B serves as the first end of the first reverse osmosis membrane group 22, the second end of the reverse osmosis membrane 1A, the second end of the reverse osmosis membrane 1B and the connection point of the second end of the reverse osmosis membrane 1C serves as the second end of the first reverse osmosis membrane group 22, the third end of the reverse osmosis membrane 1A and the third end of the reverse osmosis membrane 1B are connected to the first end of the reverse osmosis membrane 1C, and the third end of the reverse osmosis membrane 1C serves as the third end of the first reverse osmosis membrane group 22.

[0051] In the present application, when the system is in the first fresh water production mode or the second fresh water production mode, the first salinity meter SIS301 detects the produced water (fresh water) after filtering the first reverse osmosis membrane group 22. When the measured TDS value is lower than the design requirement value (for example, 400ppm), the first switch valve MV2 is opened and the second switch valve MV3 is closed after 5s. When the TDS value is higher than the highest point set by the design requirement for 3 consecutive minutes (for example, the preset value is 500ppm), the first regulating valve GV2 is adjusted in the opening direction to reduce the pressure in the first reverse osmosis membrane group 22 until the TDS value is as low as 400ppm (or the set value). After 5 minutes, the TDS value requirement for the produced water after filtering the first reverse osmosis membrane group 22 has not been met, and the system issues a light warning. If the warning exceeds 30 minutes, the fault is handled and recorded, but the shutdown is not performed. When the produced water after filtering the first reverse osmosis membrane group 22 reaches the set TDS high limit (for example, 600ppm), the system light alarms, and after the alarm exceeds 30 minutes, the fault is shut down.

[0052] In the present application, when the system is in the first fresh water production mode or the second fresh water production mode, the first flow meter FIT301 can detect the flow rate of produced water after filtration by the first reverse osmosis membrane group 22 .

[0053] In the present application, when the system is in the first fresh water production mode or the second fresh water production mode, the first switch valve MV2 starts to be normally closed. When the TDS value displayed by the first salinity meter SIS301 drops to 400ppm, the first switch valve MV2 opens, and the second switch valve MV3 closes after 5s.

[0054] In other words, within the required TDS value range, by setting the opening of the relevant regulating valve, the water pressure in the first reverse osmosis device is adjusted so that the first reverse osmosis device can operate within the specified range and close to the upper pressure limit, so that the fresh water produced by the first reverse osmosis device can be self-adaptive and automatically adjusted within the specified TDS value range to maximize the output of fresh water.

[0055] In some examples, the system includes a third pressure transmitter PIT301 and a first regulating valve GV2; The third pressure transmitter PIT301 is used to detect the water pressure at the third end of the first reverse osmosis membrane group 22 .

[0056] In the present application, when the system is in the first fresh water production mode or the second fresh water production mode, the first regulating valve GV2 is initially closed and is opened after the system is powered on; after the seawater pump 15 is running and the first-level high-pressure pump 21 is running for 3 minutes, the first regulating valve GV2 is adjusted in the closing direction to maintain the first reverse osmosis membrane group 22 at no more than 95% of the rated working pressure, or to maintain the first-level high-pressure pump 21 at no more than 95% of the rated working pressure, or the value given when the system is designed, and does not exceed the minimum value of the above values. When the value measured by the first salinity meter SIS301 for 3 consecutive minutes is higher than the highest point set by the design requirements (for example: the preset TDS value is 500ppm), the first regulating valve GV2 is adjusted in the opening direction, and the pressure at the third pressure transmitter PIT301 is reduced until the TDS value of the produced water (fresh water) filtered by the first reverse osmosis membrane group 22 is lower than 400ppm (or the set value), and the first regulating valve GV2 stops adjusting to achieve adaptive and automatic adjustment of the system pressure in the first reverse osmosis membrane group 22.

[0057] In some examples, when the system is in the first fresh water production mode or the second fresh water production mode, when the first switch valve MV2 is opened, the second switch valve MV3 is closed; when the first switch valve MV2 is closed, the second switch valve MV3 is opened.

[0058] In some examples, when the system is in the first fresh water production mode or the second fresh water production mode, the third switch valve MV8 is opened when the TDS value of the produced water (fresh water) after filtering by the first reverse osmosis membrane group 22 is higher than 450 ppm (or the set value), and the third switch valve MV8 is closed when the TDS value of the produced water (fresh water) after filtering by the first reverse osmosis membrane group 22 is lower than 400 ppm (or the set value).

[0059] In some examples, when the system is in the first fresh water production mode or the second fresh water production mode, when the third pressure transmitter PIT301 detects that the water pressure at the third end of the first reverse osmosis membrane group 22 increases and exceeds the system given limit, the opening of the first regulating valve GV2 is increased until the water pressure is within the set range; when the water pressure exceeds the upper limit of the rated working pressure, the system emits an audible and visual alarm and shuts down.

[0060] In other words, by setting the first regulating valve GV2, the second switch valve MV3, the third switch valve MV8 and the third pressure transmitter PIT301, the produced water (fresh water) filtered by the first reverse osmosis membrane group 22 that meets the set requirements can be input to the first end of the first switch valve MV2, and the produced water filtered by the first reverse osmosis membrane group 22 that does not meet the settings can be input to the inlet of the first-stage high-pressure pump 21 and pumped into the first reverse osmosis membrane group 22 for recycling and reuse. The produced water that exceeds the working capacity of the first reverse osmosis membrane group 22 and cannot be accepted is input to the concentrated water discharge pipe of the system and discharged from the concentrated water output port C. This can effectively improve the system control capability, improve the working efficiency of outputting fresh water, and enhance pressure safety protection and system reliability.

[0061] In some embodiments, the system further includes a second check valve Vz3, a third check valve Vz5, a fourth check valve Vz6, a first regulating valve MV2, a second switch valve MV3, and a third switch valve MV8; Among them, the second end of the second check valve Vz3 is connected to the first end of the first-stage high-pressure pump 21, the first end of the second check valve Vz3 is connected to the second end of the second switch valve MV3, the connection point between the first end of the third switch valve MV8 and the second end of the first reverse osmosis membrane group 22 is connected to the first end of the second switch valve MV3, the second end of the third switch valve MV8 is connected to the first end of the third check valve Vz5, the connection point between the second end of the third check valve Vz5 and the second end of the fourth check valve Vz6 is connected to the concentrated water output port C of the system, and the first end of the fourth check valve Vz6 is connected to the concentrated water output port C of the system. The first end of the first regulating valve GV2 is connected to the third end of the first reverse osmosis membrane group 22; when the first reverse osmosis membrane group 22 is in working state, when the water produced by the first reverse osmosis membrane group 22 exceeds the set requirements, it is recovered through the first-stage high-pressure pump 21 through the second switch valve MV3 and the second check valve Vz3 and enters the first reverse osmosis membrane group 22; when the water produced by the first reverse osmosis membrane group 22 exceeds the set requirements and the system cannot fully accept the recovery, it is discharged through the third switch valve MV8 to the concentrated water output port C and discharged outside the system; In other words, if the water produced by the first reverse osmosis membrane group 22 exceeds the set requirements, it will be recycled first, and the water that the system cannot accept for recycling will be discharged outside the system; in the pipeline connecting seawater (including concentrated water) and fresh water, a check valve (including a fifth check valve and a sixth check valve with similar arrangements) is arranged on the side of the regulating valve and the switch valve that contacts the seawater (including concentrated water) to prevent seawater (concentrated water with a higher salt content) from causing damage to the fresh water pipeline system.

[0062] In some examples, when the system is in the first fresh water production mode or the second fresh water production mode, when the third pressure transmitter PIT301 detects that the water pressure at the third end of the first reverse osmosis membrane group 22 increases and exceeds the system given limit, the opening of the first regulating valve GV2 is increased until the water pressure is within the set range; when the water pressure exceeds the upper limit of the rated working pressure, the system emits an audible and visual alarm and shuts down.

[0063] In other words, by setting the second check valve Vz3, the third check valve Vz5, the fourth check valve Vz6, the first regulating valve GV2, the second switch valve MV3, the third switch valve MV8 and the third pressure transmitter PIT301, it is possible to input the fresh water after reverse osmosis filtration within the set requirement range into the first end of the first switch valve MV2, and input the fresh water after reverse osmosis filtration exceeding the set requirement into the inlet of the first-stage high-pressure pump 21, and then from the first-stage high-pressure pump 21 to the first reverse osmosis membrane group 22 for recycling and reuse; the fresh water that exceeds the working capacity of the first reverse osmosis membrane group 22 and cannot be recycled is input to the concentrated water output port C of the system for discharge, thereby improving the working efficiency and reliability of the seawater desalination control system in outputting fresh water.

[0064] In some embodiments, the second reverse osmosis device includes a fourth pressure transmitter PIT302, a secondary high-pressure pump 31, a fifth pressure transmitter PIT303, a fourth switch valve MV5, a second reverse osmosis membrane group 32, a second flow meter FIT306, a second salinity meter SIS302 and a fifth switch valve MV6; Among them, the first end of the secondary high-pressure pump 31 serves as the first end of the second reverse osmosis device 32, the second end of the secondary high-pressure pump 31 is connected to the first end of the fourth switch valve MV5, the second end of the fourth switch valve MV5 is connected to the first end of the second reverse osmosis membrane group 32, the second end of the second reverse osmosis membrane group 32 is connected to the first end of the fifth switch valve MV6, the second end of the fifth switch valve MV6 is connected to the concentrated water output port C of the system, and the third end of the second reverse osmosis membrane group 32 is connected to the sixth pressure transmitter PIT304; Among them, the fourth pressure transmitter PIT302 is used to detect the water pressure at the first end of the secondary high-pressure pump 31, the fifth pressure transmitter PIT303 is used to detect the water pressure at the second end of the secondary high-pressure pump 31, the sixth pressure transmitter PIT304 is used to detect the water pressure at the third end of the second reverse osmosis membrane group 32, the second flow meter FIT306 is used to detect the flow at the second end of the second reverse osmosis membrane group 32, and the second salinity meter SIS302 is used to detect the salt content (TDS value) at the second end of the second reverse osmosis membrane group 32.

[0065] In the present application, the second reverse osmosis membrane group 32 may include a reverse osmosis membrane 2A and a reverse osmosis membrane 2B, the first end of the reverse osmosis membrane 2B serves as the first end of the second reverse osmosis membrane group 32, the connection point between the second end of the reverse osmosis membrane 2A and the second end of the reverse osmosis membrane 2B serves as the second end of the second reverse osmosis membrane group 32, the third end of the reverse osmosis membrane 2B is connected to the first end of the reverse osmosis membrane 2A, and the third end of the reverse osmosis membrane 2A serves as the third end of the second reverse osmosis membrane group 32.

[0066] In the present application, when the seawater desalination control system is in a non-operating state, the fourth switch valve MV5 is normally closed.

[0067] In the present application, when the system is in the first fresh water production mode, the fourth switch valve MV5 is normally closed.

[0068] In the present application, when the system is in the fresh water purification mode, the secondary high-pressure pump 31 inputs fresh water with a turbidity not higher than 5 NTU and a salt content (TDS) ≤ 500 ppm, preferably in the range of 0.1 MPa to 0.25 MPa, and the water pressure at the fourth pressure transmitter PIT302 is not lower than 0.05 MPa.

[0069] In the present application, when the system is in the fresh water purification mode, when the fifth pressure transmitter PIT303 detects that the water pressure at the second end of the secondary high-pressure pump 31 rises to 95% of the maximum working pressure given by the reverse osmosis membrane, membrane shell or product design, the system alarms; when the water pressure at the second end of the secondary high-pressure pump 31 exceeds the maximum limit pressure, the system issues a fault alarm and shuts down.

[0070] In the present application, when the system is in the second fresh water production mode or the system is in the fresh water purification mode, the fourth switch valve MV5 is normally open. When the system is in the fresh water purification mode, when the water pressure measured by the fourth pressure transmitter PIT302 is lower than 0.05MPa, the fourth switch valve MV5 reduces the opening degree, and when the water pressure measured by the fourth pressure transmitter PIT302 is higher than 0.20MPa, the fourth switch valve MV5 increases the opening degree to maintain the water pressure measured by the fourth pressure transmitter PIT302 within the range of 0.05MPa to 0.2MPa.

[0071] In the present application, when the system is in the fresh water purification mode, the opening of the second regulating valve GV7 is adjusted to maintain the working pressure of the secondary reverse osmosis membrane within the system design range. When the pressure displayed by the fourth pressure transmitter PIT302 is too low, the opening of the second regulating valve GV7 is reduced to compensate for the water inflow, so that the pressure at the first end of the secondary high-pressure pump 31 is not less than 0.05MPa.

[0072] In the present application, when the system is in the fresh water purification mode, after the second regulating valve GV7 is adjusted, when the water pressure measured by the sixth pressure transmitter PIT304 rises to more than 95% of the maximum working pressure given by the secondary reverse osmosis system, the second regulating valve GV7 is controlled to increase its opening until it is adjusted to 90% of the given maximum working pressure; when the water pressure measured by the sixth pressure transmitter PIT304 reaches the maximum working pressure given by the system design, the system automatically shuts down and issues an audible and visual alarm (the alarm setting range is adjustable).

[0073] In the present application, when the system is in the fresh water purification mode, after the secondary high-pressure pump 31 works for 3 minutes, when the TDS value of the purified fresh water reaches the control value of 45ppm for 5 consecutive minutes, an audible alarm is triggered (the alarm does not stop the machine), and when it drops below the limit value, the alarm is canceled. When the purified fresh water exceeds the limit value of 55ppm, the fifth switch valve MV6 switches to the state where the fresh water outlet is closed and the concentrated water outlet C is passed. The system's sound and light (changing light) alarm (the alarm does not stop the machine), and 15 minutes later, if the purified fresh water still exceeds the limit value, the system stops and alarms. The second salinity meter SIS302 detects the TDS data and alarm information of the purified fresh water, which are recorded by the equipment system. When shutting down for normal operation, the fifth switch valve MV6 is in a state where the concentrated water outlet C is closed and the fresh water outlet D is passed.

[0074] In some embodiments, the system further includes a sixth pressure transmitter PIT304, a second regulating valve GV7, a third regulating valve GV3, a third flow meter FIT304, and a fifth check valve Vz4; Among them, the first end of the second regulating valve GV7 is connected to the third end of the second reverse osmosis membrane group 32, and the second end of the second regulating valve GV7 is connected to the first end of the secondary high-pressure pump 31; the first end of the third regulating valve GV3 is connected to the third end of the second reverse osmosis membrane group 32, the second end of the second regulating valve GV7 is connected to the first end of the secondary high-pressure pump, the second end of the third regulating valve GV3 is connected to the first end of the third flowmeter, the second end of the third flowmeter is connected to the first end of the fifth check valve Vz5, the second end of the fifth check valve Vz5 is connected to the second end of the filtering device, and the third flowmeter FIT304 is used for detection, and the third regulating valve GV3 is controlled according to the detection result to adjust the flow rate delivered from the third end of the second reverse osmosis membrane group 32 to the first reverse osmosis device.

[0075] In some examples, the fourth pressure transmitter PIT302 detects the pressure of the fresh water purified by the first reverse osmosis device at the water inlet of the secondary high-pressure pump 31. When the water production pressure at the second end of the first reverse osmosis membrane group 22 is too low, the second regulating valve GV7 is controlled to adjust the pressure in the second reverse osmosis membrane group 32, and the concentrated water (fresh water with a high salt content) at the third end of the second reverse osmosis membrane group 32 is recycled and utilized to increase the total water inlet of the secondary high-pressure pump 31, while ensuring that the water pressure at the second end of the first reverse osmosis membrane group 22 is not less than 0.05 MPa; when the water pressure at the first end of the secondary high-pressure pump 31 exceeds 0.2 MPa, the second regulating valve GV7 is controlled to adjust the water pressure to between 0.05 MPa and 1.5 MPa; when the water pressure at the first end of the secondary high-pressure pump 31 is lower than 0.1 MPa (gauge pressure 0 MPa) in absolute pressure, the control system issues an audible and visual alarm (without stopping the machine); when the water pressure of the fresh water purified by the first reverse osmosis device exceeds 0.3 MPa or reaches the alarm value of the set pressure upper limit, the control system automatically stops and issues an audible and visual alarm.

[0076] In the present application, when the system is in the fresh water purification mode or the first fresh water production mode, when the water pressure measured by the sixth pressure transmitter PIT304 exceeds 95% of the maximum working pressure given by the secondary reverse osmosis system, the third regulating valve GV3 increases the opening until it is adjusted to 90% of the given maximum working pressure (maintaining the pressure within the range of 90% to 95%, or within the set required range). When the water pressure measured by the sixth pressure transmitter PIT304 reaches the maximum working pressure given by the system design, the system automatically shuts down and issues an audible and visual alarm (the alarm range is adjustable). When the second salinity meter SIS302 detects that the TDS value of the purified fresh water exceeds 50ppm, the third regulating valve GV3 is controlled to increase the opening to reduce the water pressure in the second reverse osmosis membrane group 32 until the TDS value of the purified fresh water drops to within the range of 30 to 40ppm. If necessary, it can be adjusted to a set point within the range of 2 to 40ppm.

[0077] In some embodiments, the system further comprises a sixth check valve Vz7; The first end of the sixth check valve Vz7 is connected to the third end of the fifth switch valve MV5, and the second end of the sixth check valve Vz7 is connected to the concentrated water output port C of the system.

[0078] In other words, by providing the sixth check valve Vz7, the backflow of seawater with higher salinity to the fresh water output port D can be effectively reduced, thereby effectively improving the quality of fresh water output from the fresh water output port D of the seawater desalination control system.

[0079] In some embodiments, the system further includes an eighth switch valve V10 and a fourth pressure gauge PI310; The eighth switch valve V10 is connected between the fresh water interface G of the system and the first end of the second reverse osmosis device; Among them, the fourth pressure gauge PI310 can display the water pressure of the fresh water output by the first reverse osmosis device when it enters the first end of the secondary high-pressure pump 31, can display the water pressure of the fresh water output by the first reverse osmosis device when it passes through the fresh water interface G port, and can display the water pressure of the fresh water input from the external source before entering the first end of the secondary high-pressure pump 31.

[0080] By setting the eighth switch valve V10, the fresh water interface G port can be opened or closed.

[0081] In some embodiments, the system further includes a sixth switch valve V16 and a seventh switch valve V8; The sixth switch valve V16 is connected to the first end of the fifth switch valve MV5, and the seventh switch valve V8 is connected to the first end of the first switch valve MV2.

[0082] By providing the sixth switch valve V16 and the seventh switch valve V8, sampling ports can be used to take water and sample the fresh water output from the second reverse osmosis device and the fresh water output from the first reverse osmosis device.

[0083] Through the description of the specific implementation method, the reverse osmosis seawater desalination control system is explained. The seawater is filtered and desalinated by reverse osmosis through a filtering device and a first reverse osmosis device to obtain purified fresh water; the purified fresh water is subjected to a second reverse osmosis purification treatment through a second reverse osmosis device to obtain high-purity fresh water; the exogenous fresh water can be re-purified through the second reverse osmosis device to obtain high-purity fresh water. An embodiment of the present disclosure shows that a seawater desalination device can supply fresh water for daily use and high-purity purified drinking water, and can also purify general fresh water and output purified high-purity drinking water, effectively expanding the application scenarios and water production capacity of the seawater desalination equipment.

[0084] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A seawater desalination control system, characterized in that: The system comprises: A filtering device, wherein a first end of the filtering device is used to connect to a seawater inlet of the system, and the seawater inlet is used to introduce seawater to be treated; a first reverse osmosis device, wherein a first end of the first reverse osmosis device is connected to a second end of the filtering device; a second reverse osmosis device, wherein the first end of the second reverse osmosis device is connected to the second end of the first reverse osmosis device, the first end of the second reverse osmosis device is used to connect to the fresh water interface of the system, the fresh water interface is used to introduce unpurified fresh water, and the second end of the second reverse osmosis device is used to connect to the fresh water output port of the system; the third end of the second reverse osmosis device is connected to the first end of the first reverse osmosis device and the first end of the second reverse osmosis device; Wherein, the system includes a first fresh water production mode, a second fresh water production mode and a fresh water purification mode; When the system is in the first fresh water production mode, the filtering device filters the seawater to be treated delivered from the seawater inlet of the system to obtain and deliver the filtered seawater to the first reverse osmosis device, and the first reverse osmosis device performs a first reverse osmosis device purification treatment on the filtered seawater to obtain and output the reverse osmosis filtered fresh water to the fresh water interface of the system; When the system is in the second fresh water production mode, the filtering device filters the seawater to be treated delivered from the seawater inlet of the system to obtain filtered seawater and delivers it to the first reverse osmosis device; the first reverse osmosis device performs reverse osmosis purification on the filtered seawater to obtain reverse osmosis purified fresh water and delivers it to the second reverse osmosis device; the second reverse osmosis device performs reverse osmosis purification on the fresh water after reverse osmosis purification in the second reverse osmosis device again, and delivers the purified high-purity fresh water from the fresh water output port of the system; When the system is in the fresh water purification mode, exogenous fresh water with relatively high salt content is connected from the fresh water interface of the system, transported to the second reverse osmosis device for reverse osmosis purification, and the purified high-purity fresh water is output from the fresh water output port of the system.

2. The system according to claim 1, characterized in that The filtering device comprises a water inlet control valve, a first pressure gauge, a seawater pump, a flow control valve, a first pressure transmitter, a filter, a multi-way valve, a fine filter and a safety filter; Wherein, the first end of the water inlet control valve serves as the first end of the filtering device, the second end of the water inlet control valve is connected to the first end of the seawater pump, the second end of the seawater pump is connected to the first end of the flow control valve, the second end of the flow control valve is connected to the first end of the multi-way valve, the second end of the multi-way valve is connected to the first end of the filter, the second end of the filter is connected to the third end of the multi-way valve, the fourth end of the multi-way valve is connected to the first end of the fine filter, the second end of the fine filter is connected to the first end of the safety filter, and the second end of the safety filter serves as the second end of the filtering device; The first pressure gauge is used to detect and display the water pressure at the first end of the seawater pump, and the first pressure transmitter is used to detect the water pressure at the second end of the seawater pump.

3. The system according to claim 2, characterized in that The system also includes a first discharge valve, a second discharge valve and a third discharge valve. The second end of the filter is connected to the first end of the first discharge valve, the connection point between the second end of the first discharge valve and the fifth end of the multi-way valve is connected to the concentrated water output port of the system, the third end of the fine filter is connected to the first end of the second discharge valve, the third end of the safety filter is connected to the first end of the third discharge valve, and the connection point between the second end of the second discharge valve and the second end of the third discharge valve is connected to the concentrated water output port of the system.

4. The system according to claim 1, characterized in that The first reverse osmosis device includes a second pressure transmitter, a primary high-pressure pump, a first check valve, a second pressure gauge, a first reverse osmosis membrane group, a first salinity meter, a first flow meter, a third pressure gauge and a first switch valve; The first end of the primary high-pressure pump serves as the first end of the first reverse osmosis device, the second end of the primary high-pressure pump is connected to the first end of the first check valve, the second end of the first check valve is connected to the first end of the first reverse osmosis membrane group, the second end of the first reverse osmosis membrane group is connected to the first end of the first switch valve, and the second end of the first switch valve serves as the second end of the first reverse osmosis device; The second pressure transmitter is used to detect the water pressure at the first end of the first-stage high-pressure pump, the second pressure gauge is used to detect and display the water pressure at the first end of the first reverse osmosis membrane group, the first salinometer is used to detect the salt content at the second end of the first reverse osmosis membrane group, the first flow meter is used to detect the flow rate at the second end of the first reverse osmosis membrane group, and the third pressure gauge is used to detect and display the water pressure at the second end of the first reverse osmosis membrane group.

5. The system according to claim 1, characterized in that The first reverse osmosis device includes a second check valve, a third check valve, a second switch valve and a third switch valve; Wherein, the second end of the second check valve is connected to the first end of the primary high-pressure pump, the first end of the second check valve is connected to the second end of the second switch valve, the first end of the second switch valve is connected to the first end of the first switch valve, the first end of the third switch valve is connected to the first end of the first switch valve, the second end of the third switch valve is connected to the first end of the third check valve, and the second end of the third check valve is connected to the concentrated water output port of the system; When the produced water of the first reverse osmosis device is detected by the first salinity meter and is determined to be beyond the control range, the second switch valve is opened and the produced water is introduced into the first end of the first reverse osmosis device through the second check valve to be recycled. The part that cannot be recycled by the first reverse osmosis device is discharged to the outside of the system through the concentrated water output port through the third switch valve and the third check valve.

6. The system according to claim 4, characterized in that The system further comprises a third pressure transmitter, a first regulating valve, and a fourth check valve; Wherein, the third end of the first reverse osmosis membrane group is connected to the first end of the first regulating valve, the second end of the first regulating valve is connected to the first end of the fourth check valve, and the second end of the fourth check valve is connected to the concentrated water output port of the system; The third pressure transmitter is used to detect the water pressure at the third end of the first reverse osmosis membrane group, and the first regulating valve regulates the working pressure of the first reverse osmosis membrane group.

7. The system according to claim 1, characterized in that The second reverse osmosis device includes a fourth pressure transmitter, a secondary high-pressure pump, a fifth pressure transmitter, a fourth switch valve, a first reverse osmosis membrane group, a second flow meter, a second salinity meter and a fifth switch valve; Wherein, the first end of the secondary high-pressure pump serves as the first end of the second reverse osmosis device, the second end of the secondary high-pressure pump is connected to the first end of the fourth switch valve, the second end of the fourth switch valve is connected to the first end of the second reverse osmosis membrane group, the second end of the second reverse osmosis membrane group is connected to the first end of the fifth switch valve, the second end of the fifth switch valve is connected to the concentrated water output port of the system, the third end of the second reverse osmosis membrane group is connected to the second end of the second regulating valve, and the first end of the second regulating valve is connected to the first end of the secondary high-pressure pump; The fourth pressure transmitter is used to detect the water pressure at the first end of the secondary high-pressure pump, the fifth pressure transmitter is used to detect the water pressure at the second end of the secondary high-pressure pump, the second flow meter is used to detect the flow at the second end of the second reverse osmosis membrane group, and the second salinity meter is used to detect the salt content at the second end of the second reverse osmosis membrane group.

8. The system according to claim 7, characterized in that The second reverse osmosis device further includes a sixth pressure transmitter, a second regulating valve, a third regulating valve, a third flow meter, and a fifth check valve; Wherein, the third end of the second reverse osmosis membrane group is connected to the first end of the second regulating valve, the second end of the second regulating valve is connected to the first end of the secondary high-pressure pump, the first end of the third regulating valve is connected to the third end of the second reverse osmosis membrane group, the second end of the third regulating valve is connected to the first end of the third flow meter, the second end of the third flow meter is connected to the first end of the fifth check valve, and the second end of the fifth check valve is connected to the second end of the filtering device; The sixth pressure transmitter is used to detect the water pressure at the third end of the second reverse osmosis membrane group, the third flowmeter is used to detect the flow at the third end of the third regulating valve, the third regulating valve controls the flow to the first end of the first reverse osmosis device through the fifth check valve, and the second regulating valve adjusts the water pressure at the third end of the second reverse osmosis device.

9. The system according to claim 7, characterized in that The system also includes a sixth check valve; Wherein, the third end of the fifth switch valve is connected to the first end of the sixth check valve, and the second end of the sixth check valve is connected to the concentrated water output port of the system; The water produced by the second reverse osmosis membrane group exceeds the set requirement and is discharged to the concentrated water output port through the third end of the fifth switch valve and the sixth check valve.

10. The system according to claim 1, characterized in that The system also includes an eighth switch valve and a fourth pressure gauge; Wherein, the eighth switch valve is connected between the first end of the second reverse osmosis device and the fresh water interface of the system; The fourth pressure gauge detects and displays the water pressure of the fresh water output by the first reverse osmosis device at the first end of the secondary high-pressure pump, displays the water pressure of the fresh water output by the first reverse osmosis device before passing through the fresh water interface, and displays the water pressure of the fresh water input from an external source before entering the first end of the secondary high-pressure pump.

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