CN203689090U - PLC fuzzy adaptive seawater salinity test device - Google Patents

Abstract

A PLC fuzzy self-adaptive seawater salinity test device belongs to the field of PLC fuzzy self-adaptive control, the test device is composed of a seawater salinity test platform and a PLC salinity control system, the seawater salinity test platform includes a test box, a mother liquor Tank and recovery tank, the mother liquid tank transports seawater to the test chamber through the seawater input pipeline, and the seawater test solution in the test chamber is transported to the recovery tank through the recovery pipeline, and the recovery tank is connected with an outlet pipeline. The PLC control unit in the PLC salinity control system adaptively controls the different salinity levels in the seawater salinity test platform through the I/O drive circuit interface module according to the detected liquid level and salinity information in the test chamber, mother liquor tank and recovery tank. The on-off control of the electromagnetic valve is carried out, so as to finally realize the adaptive control of the liquid level and salinity of the seawater test solution in the test chamber. The utility model can conveniently realize multi-point adaptive control of the seawater salinity according to different requirements of the seawater salinity test.

Description

A PLC fuzzy adaptive seawater salinity test device

technical field

The utility model belongs to the field of PLC fuzzy adaptive control, in particular to a seawater salinity test device based on PLC fuzzy adaptive control.

Background technique

Seawater is an electrolyte solution containing a variety of salts, with 3% to 3.5% sodium chloride as the main salt, in which the content of chloride ions is very large, high salt content, sand content and usually dissolved air The characteristics make seawater highly corrosive to metals. In the protective coating technology of metal components and the research of seawater corrosion-resistant steel, it is usually necessary to conduct corrosion tests on metal components under different seawater salinity conditions, because seawater concentration control has no fixed mathematical model and is dynamic, and at the same time the salinity There is an inherent time delay in the sensor, and conventional automatic control devices often cannot meet the requirements for controlling the salinity of the test solution.

Utility model content

The purpose of this utility model is to provide a seawater salinity test device based on PLC adaptive control. The adaptability of the salinity test device to changes in test conditions.

In order to achieve the above object, the technical solution of the present utility model is: a PLC fuzzy adaptive seawater salinity test device, which is composed of a seawater salinity test platform and a PLC salinity control system, the seawater salinity test platform Including test chamber, mother liquid tank and recovery tank, the mother liquid tank transports seawater to the test chamber through the seawater input pipeline, the seawater test solution in the test chamber is transported to the recovery tank through the recovery pipeline, and the recovery liquid in the recovery tank passes through the outlet pipe After the two channels flow out, one is sent to the mother liquid tank by the seawater circulation pipeline, and the other is discharged through the discharge pipeline. The seawater input pipeline, the recovery pipeline, the seawater circulation pipeline and the discharge pipeline are respectively equipped with a brine solenoid valve, Water discharge solenoid valve, seawater recovery pump and discharge solenoid valve. The test box is connected with a fresh water input pipeline, and a fresh water solenoid valve is installed on the fresh water input pipeline. The test box is also equipped with a seawater test solution circulation loop. A seawater circulation pump is provided on the solution circulation circuit;

The PLC salinity control system comprises an industrial computer, a PLC control unit, an I/O drive circuit interface module, a sensor interface module, a salinity sensor and a liquid level sensor, and the industrial computer is the upper computer of the test device, and is controlled with the PLC The unit performs data communication. The salinity sensor and liquid level sensor are used to detect the salinity and liquid level information in the test chamber, mother liquor tank and recovery tank. The signal output terminal of the salinity sensor and liquid level sensor is connected to the signal input of the sensor interface module. The signal output terminal of the sensor interface module is connected to the analog input port of the PLC control unit, the I/O control port of the PLC control unit is connected to the I/O control input port of the I/O drive circuit interface module, and the I/O The I/O control output ports of the drive circuit interface module (20) are respectively connected to the driving ends of the seawater circulation pump, the seawater recovery pump, the freshwater solenoid valve, the saltwater solenoid valve, the drain solenoid valve and the discharge solenoid valve.

Beneficial effects: the utility model can adaptively adjust the salinity and liquid level of the seawater test solution according to different requirements of the seawater test solution, conveniently realize multi-point adaptive control of the seawater salinity, and improve the seawater salinity test device. It is adaptable to changes in test conditions, and can obtain high seawater test solution preparation accuracy and short preparation time.

Description of drawings

Fig. 1 is the overall structural relationship diagram of the present utility model;

Fig. 2 is the pipeline schematic diagram of the utility model seawater salinity test device;

Fig. 3 is the schematic circuit diagram of the utility model PLC salinity control system;

Fig. 4 is the circuit schematic diagram of the utility model I/O drive circuit interface module;

The marks in the figure are: 1. Test chamber, 2. Mother liquid tank, 3. Recovery tank, 4. Sea water circulation pump, 5. Sea water recovery pump, 6. Fresh water solenoid valve, 7. Salt water solenoid valve, 8. Water discharge solenoid valve, 9. Discharge solenoid valve, 10. PLC control unit, 11. Industrial computer, 12. Salinity sensor Ⅰ, 13. Liquid level sensor Ⅰ, 14. Salinity sensor Ⅱ, 15. Liquid level sensor Ⅱ, 16. Salinity sensor III, 17. Liquid level sensor III, 18. Sensor interface module I, 19. Sensor interface module II, 20. I/O drive circuit interface module.

Detailed ways

As shown in Fig. 1 and Fig. 2, a kind of PLC fuzzy adaptive seawater salinity test device, this test device is made up of seawater salinity test platform and PLC salinity control system, described seawater salinity test platform comprises test box 1 , mother liquid tank 2 and recovery tank 3, the mother liquid tank 2 transports seawater to the test chamber 1 through the seawater input pipeline, the seawater test solution in the test chamber 1 is transported to the recovery tank 3 through the recovery pipeline, and the recovery in the recovery tank 3 After the liquid flows out through the outlet pipeline, one is sent to the mother liquid tank 2 by the seawater circulation pipeline, and the other is discharged through the discharge pipeline. The seawater input pipeline, recovery pipeline, seawater circulation pipeline and discharge pipeline are respectively provided with There are salt water solenoid valve 7, water discharge solenoid valve 8, seawater recovery pump 5 and discharge solenoid valve 9. The test box 1 is connected with a fresh water input pipeline, and a fresh water solenoid valve 6 is arranged on the fresh water input pipeline. A seawater test solution circulation loop is also provided, and a seawater circulation pump 4 is arranged on the seawater test solution circulation loop.

Among them, the test chamber 1 is used to simulate the seawater test environment under different salinities, the mother liquid tank 2 provides high-salinity seawater mother liquid for the preparation of seawater with different salinities in the test chamber 1, and the recovery tank 3 is used for recovery and temporary storage of the test chamber 1 the seawater test solution discharged, the seawater circulation pump 4 is used for uniform mixing of the seawater test solution during the salinity preparation process in the test chamber 1, the seawater recovery pump 5 is used for recovering the seawater test solution with higher salinity in the recovery tank 3, fresh water Solenoid valve 6, salt water solenoid valve 7 and water discharge solenoid valve 8 are used to control the salinity and volume of the seawater test solution in the test chamber 1, and the discharge solenoid valve 9 is used to discharge the low-salinity seawater test solution in the recovery tank 3.

The PLC salinity control system includes an industrial computer 11, a PLC control unit 10, an I/O drive circuit interface module 20, a sensor interface module, a salinity sensor and a liquid level sensor, and the industrial computer 11 is the upper computer of the test device, And carry out data communication with the PLC control unit 10, the salinity sensor and the liquid level sensor are used to detect the salinity and liquid level information in the test chamber 1, the mother liquid tank 2 and the recovery tank 3, and the signal output of the salinity sensor and the liquid level sensor end is connected with the signal input end of the sensor interface module, the signal output end of the sensor interface module is connected with the analog input port of the PLC control unit 10, the I/O control port of the PLC control unit 10 is connected with the I/O drive circuit interface module 20 The I/O control input port is connected, and the I/O control output port of the I/O drive circuit interface module 20 is respectively connected with the seawater circulation pump 4, the seawater recovery pump 5, the fresh water solenoid valve 6, the salt water solenoid valve 7, the water discharge solenoid valve 8 and The drive end of the discharge solenoid valve 9 is connected. Among them, the salinity sensor and the liquid level sensor transmit the collected salinity and liquid level signals in the test chamber 1, the mother liquor tank 2 and the recovery tank 3 to the sensor interface module, and the sensor interface module transmits the received salinity and liquid level signals The signal is transmitted to the PLC control unit 10, and the PLC control unit 10 realizes the start-stop control of the seawater circulation pump 4 and the seawater recovery pump 5 through the I/O drive circuit interface module 20, as well as the fresh water solenoid valve 6, the salt water solenoid valve 7, and the water discharge solenoid valve 8 and the on-off control of the discharge solenoid valve 9.

Wherein, the salinity sensor includes a salinity sensor I12, a salinity sensor II14 and a salinity sensor III16, and the liquid level sensor includes a liquid level sensor I13, a liquid level sensor II15 and a liquid level sensor III17. The salinity sensor I12 and the liquid level sensor I13 are respectively installed inside and on the upper part of the test chamber 1, and are used to detect the salinity and liquid level of the seawater test solution in the test chamber 1. The salinity sensor II14 and the liquid level sensor II15 are respectively installed in the The interior of the mother liquid tank 2 and the upper part of the mother liquid tank 2 are used to detect the salinity and liquid level of the seawater mother liquid in the mother liquid tank 2. The salinity sensor III16 and the liquid level sensor III17 are respectively installed inside the recovery tank 3 and on the upper part of the recovery tank 3 , used for detecting the salinity and liquid level of the seawater discharged in the recovery tank 3 .

The sensor interface module includes a sensor interface module I18 and a sensor interface module II19.

The 4-20mA signal output terminal of the salinity sensor Ⅰ12 and the 4-20mA signal output terminal of the liquid level sensor Ⅰ13 are respectively connected with the corresponding 4-20mA signal input terminal of the sensor interface module Ⅰ18; the 4-20mA signal output terminal of the salinity sensor Ⅱ14 , The 4-20mA signal output terminal of the liquid level sensor II15 is respectively connected with the corresponding 4-20mA signal input terminal of the sensor interface module I18; the 4-20mA signal output terminal of the salinity sensor III16, the 4-20mA signal output of the liquid level sensor III17 The terminals are respectively connected to the corresponding 4-20mA signal input terminals of the sensor interface module II19; the 4-20mA signal output terminals of the sensor interface module I18 and the sensor interface module II194-20mA signal output terminals are respectively connected to the corresponding analog input ports of the PLC control unit 10 connect.

The 220V power supply interface of PLC control unit 10 is respectively connected with the 220V power supply output interface of 220V power supply 1 module; The 24V power supply interface of the circuit interface module 20 is connected with the 24V power supply output interface of the 24V power supply module respectively; The I/O control port of the PLC control unit 10 is connected with the corresponding I/O control input port of the I/O drive circuit interface module 20; The I/O control output port of the /O drive circuit interface module 20 is respectively connected with the I/O control of the fresh water solenoid valve 6, the salt water solenoid valve 7, the water discharge solenoid valve 8, the discharge solenoid valve 9, the seawater circulation pump 4, and the seawater recovery pump 5. The input port is connected; the PLC control unit 10 realizes the on-off control of the seawater circulation pump 4, the on-off control of the fresh water solenoid valve 6, the salt water solenoid valve 7, and the water discharge solenoid valve 8 through the I/O drive circuit interface module 20, so as to realize the mother liquor Self-adaptive preparation of high-salinity seawater mother liquor in tank 2 and tap water with different salinity seawater test solutions in test chamber 1.

As shown in Figure 3, the PLC salinity control system uses the industrial computer 11 as the upper computer of the seawater salinity test device; the PLC control unit 10 is the field control unit of the seawater salinity test device; The monitoring software of salinity test device, the RS232 communication interface of industrial computer 11 is connected with the RS485 communication interface of PLC control unit 10, realizes the data communication between PLC control unit 10 and industrial computer 11; PLC control unit 10 utilizes fuzzy control, switch control The fuzzy self-adaptive seawater salinity control program module is composed of such control strategies, which realizes self-adaptive fuzzy control of seawater salinity and builds a seawater salinity fuzzy self-adaptive control platform. Among them: the 4-20mA signal output terminals A1 and B1 of the salinity sensor I12 installed inside the test box 1 are respectively connected to the 4-20mA signal input terminals A1 and B1 of the sensor interface module I18; the liquid level installed on the upper part of the test box 1 The 4-20mA signal output terminals A2 and B2 of the sensor I13 are respectively connected to the 4-20mA signal input terminals A2 and B2 of the sensor interface module I18; the 4-20mA signal output terminals A1, B1 and 4-20mA signal output of the sensor interface module I18 The terminals A2 and B2 are respectively connected to the analog input ports A1, B1 and A2 and B2 of the PLC control unit 10; the 4-20mA signal output terminals A3 and B3 of the salinity sensor II 14 installed inside the mother liquid tank 2 are respectively connected to the sensor interface module The 4-20mA signal input terminals A3 and B3 of Ⅰ18 are connected; the 4-20mA signal output terminals A4 and B4 of the liquid level sensor II15 installed on the upper part of the mother liquid tank 2 are respectively connected with the 4-20mA signal input terminals A4 and B4 of the sensor interface module Ⅰ18 Connection; the 4-20mA signal output terminals A3, B3 and 4-20mA signal output terminals A4 and B4 of the sensor interface module I18 are respectively connected to the analog input ports A3, B3 and A4 and B4 of the PLC control unit 10; installed in the recovery tank 3 The 4-20mA signal output terminals A5 and B5 of the internal salinity sensor Ⅲ16 are respectively connected to the 4-20mA signal input terminals A5 and B5 of the sensor interface module Ⅱ19; the 4-20mA of the liquid level sensor Ⅲ17 installed on the upper part of the recovery tank 3 The signal output terminals A6 and B6 are respectively connected to the 4-20mA signal input terminals A6 and B6 of the sensor interface module II19; the 4-20mA signal output terminals A5, B5 and 4-20mA signal output terminals A6 and B6 of the sensor interface module II19 are respectively connected to The analog quantity input port A5, B5 of PLC control unit 10 is connected with A6, B6; The I/O control port Q0.0, Q0.1, Q0.2, Q0.3, Q0.4, Q0. 5 are respectively connected with the I/O control input port Q0.0, Q0.1, Q0.2, Q0.3, Q0.4, Q0.5 of the I/O drive circuit interface module 20; the I/O of the PLC control unit 10 The ground terminal M of the O control port is connected to the ground terminal GND of the I/O drive circuit interface module 20; the I/O control output port KQ0.0 of the I/O drive circuit interface module 20, the The ground terminal GND is respectively connected to the drive terminal KQ0.0 and the ground terminal GND of the fresh water solenoid valve 6; The terminal GND is respectively connected to the driving terminal KQ0.1 and the grounding terminal GND of the brine solenoid valve 7; the I/O control output port KQ0.2 of the I/O drive circuit interface module 20 is connected to the ground terminal of the I/O drive circuit interface module 20 GND respectively It is connected with the driving terminal KQ0.2 and the grounding terminal GND of the drain solenoid valve 8; the I/O control output port KQ0.3 of the I/O driving circuit interface module 20, and the grounding terminal GND of the I/O driving circuit interface module 20 are respectively The drive terminal KQ0.3 of the discharge solenoid valve 9 is connected to the ground terminal GND; the I/O control output port KQ0.4 of the I/O drive circuit interface module 20, and the ground terminal KM of the I/O drive circuit interface module 20 are respectively connected to the seawater The drive end KQ0.4 of the circulating pump 4 is connected to the power supply end N2; the I/O control output port KQ0.5 of the I/O drive circuit interface module 20, the ground terminal GND of the I/O drive circuit interface module 20 are respectively connected to the seawater recovery The drive terminal KQ0.5 of the pump 5 is connected to the power terminal N2; the power input terminals L1 and N1 of the PLC control unit 10 are respectively connected to the output terminals L1 and N1 of the 220V input power supply.

The I/O drive circuit interface module 20 in this device is shown in FIG. 4 . The 24V power input terminal +24V and the ground terminal GND of the I/O drive circuit interface module 20 are respectively connected to the power output terminal +24V and the ground terminal GND of the external switching power supply; the 220V power supply input terminal L2 of the I/O drive circuit interface module 20 , N2 are respectively connected to the output terminals L2 and N2 of the 220V input power supply; the I/O control input ports Q0.0, Q0.1, Q0.2, Q0.3, Q0.4, Q0.5 is respectively connected with the I/O control ports Q0.0, Q0.1, Q0.2, Q0.3, Q0.4, Q0.5 of the PLC control unit 10; the I/O control ports of the PLC control unit 10 The ground terminal M of the I/O drive circuit interface module 20 is connected to the ground terminal GND; the I/O control input port Q0.0 of the I/O drive circuit interface module 20 is connected to the control terminal Q0.0 of the intermediate relay KA0; I The ground terminal GND of the /O drive circuit interface module 20 is connected to the control ground terminal GND of the intermediate relay KA0; the input terminal IQ0.0 of the intermediate relay KA0 is connected to the 24V power input terminal +24V of the I/O drive circuit interface module 20; the middle The output terminal KQ0.0 of the relay KA0 is connected to the drive terminal KQ0.0 of the fresh water solenoid valve 6; the ground terminal GND of the I/O drive circuit interface module 20 is connected to the ground terminal GND of the fresh water solenoid valve 6; the I/O drive circuit interface The I/O control input port Q0.1 of the module 20 is connected to the control terminal Q0.1 of the intermediate relay KA1; the ground terminal GND of the I/O drive circuit interface module 20 is connected to the control ground terminal GND of the intermediate relay KA1; the intermediate relay KA1 The input terminal IQ0.1 of the I/O drive circuit interface module 20 is connected to the 24V power supply input terminal +24V; the output terminal KQ0.1 of the intermediate relay KA1 is connected to the drive terminal KQ0.1 of the brine solenoid valve 7; the I/O drive The ground terminal GND of the circuit interface module 20 is connected with the ground terminal GND of the brine solenoid valve 7; the I/O control input port Q0.2 of the I/O drive circuit interface module 20 is connected with the control terminal Q0.2 of the intermediate relay KA2; I The ground terminal GND of the /O drive circuit interface module 20 is connected to the control ground terminal GND of the intermediate relay KA2; the input terminal IQ0.2 of the intermediate relay KA2 is connected to the 24V power input terminal +24V of the I/O drive circuit interface module 20; The output terminal KQ0.2 of the relay KA2 is connected to the drive terminal KQ0.2 of the water discharge solenoid valve 8; the ground terminal GND of the I/O drive circuit interface module 20 is connected to the ground terminal GND of the water discharge solenoid valve 8; the I/O drive circuit interface The I/O control input port Q0.3 of the module 20 is connected to the control terminal Q0.3 of the intermediate relay KA3; the ground terminal GND of the I/O drive circuit interface module 20 is connected to the control ground terminal GND of the intermediate relay KA3; the intermediate relay KA3 The input terminal IQ0.3 and the I/O drive circuit The 24V power input terminal of the interface module 20 is connected to +24V; the output terminal KQ0.3 of the intermediate relay KA3 is connected to the drive terminal KQ0.3 of the discharge solenoid valve 9; the ground terminal GND of the I/O drive circuit interface module 20 is connected to the discharge solenoid valve 9 is connected to the ground terminal GND; the I/O control input port Q0.4 of the I/O drive circuit interface module 20 is connected to the control terminal Q0.4 of the intermediate relay KA4; the ground terminal GND of the I/O drive circuit interface module 20 is connected to The control ground terminal GND of the intermediate relay KA4 is connected; the input terminal IQ0.4 of the intermediate relay KA4 is connected with the 220V power input terminal L2 of the I/O drive circuit interface module 20; the output terminal KQ0.4 of the intermediate relay KA4 is connected with the seawater circulation pump 4 The drive terminal KQ0.4 of the I/O drive circuit interface module 20 is connected to the 220V power supply output terminal N2 of the seawater circulation pump 4; the I/O control input port Q0 of the I/O drive circuit interface module 20 .5 is connected to the control terminal Q0.5 of the intermediate relay KA5; the ground terminal GND of the I/O drive circuit interface module 20 is connected to the control ground terminal GND of the intermediate relay KA5; the input terminal IQ0.5 of the intermediate relay KA5 is connected to the I/O The 220V power supply input terminal L2 of the drive circuit interface module 20 is connected; the output terminal KQ0.5 of the intermediate relay KA5 is connected to the drive terminal KQ0.5 of the seawater recovery pump 5; the 220V power supply output terminal N2 of the I/O drive circuit interface module 20 is connected to the The power input terminal N2 of the seawater recovery pump 5 is connected.

The control method of the utility model PLC fuzzy adaptive seawater salinity test device comprises the following steps:

(1) The PLC control unit collects the data of the salinity sensor and the liquid level sensor, and the industrial computer displays the salinity and liquid level data collected by the PLC control unit on the monitoring interface;

(2) The user sets the control parameters on the monitoring interface, the control parameters include the change rate of the salinity of the seawater test solution in the test chamber, the salinity of the seawater test solution and the number of points prepared for the salinity of the seawater test solution;

(3) The PLC control unit selects the setting value of the salinity change rate of the seawater test solution according to the salinity preparation accuracy of the seawater test solution, and sets the salinity preparation process of the seawater test solution differently according to the change in the liquid level of the seawater test solution According to the salinity detection value, the salinity set value and the selected salinity change rate set value, the salinity deviation flag value and the salinity change rate deviation value of the seawater test solution are calculated, and then the fuzzy Control the look-up table to adaptively judge the value of the switch control mode that should be selected;

(4) The switch control module of the PLC control unit further controls the seawater circulation pump and seawater recovery pump through the I/O drive circuit interface module according to the salinity deviation flag value calculated in step (3) and the selected switch control mode value. The start and stop of the fresh water solenoid valve, the salt water solenoid valve, the water discharge solenoid valve and the discharge solenoid valve are controlled on and off, so as to realize the adaptive control of the salinity and liquid level of the seawater test solution in the test chamber.

The above step (3) is adjusted and controlled by the fuzzy self-adaptive seawater salinity adjustment module in the PLC control unit.

The switch control module of the PLC control unit is based on the control value of the seawater test solution mode output by the fuzzy self-adaptive seawater salinity adjustment module and the liquid level change data of the seawater test solution in the test chamber 1. The on/off of the electromagnetic valve 7 and the water discharge electromagnetic valve 8 is controlled to realize the adjustment of the salinity of the seawater test solution in the test chamber 1. At the same time, in order to ensure the uniformity of the salinity of the seawater test solution in the test chamber 1, the seawater circulation pump 4 is used throughout the test chamber. It is running during the preparation process; the fuzzy self-adaptive seawater salinity adjustment module is responsible for detecting the change rate of the salinity of the seawater test solution in the test chamber, and for adding fresh water or increasing the salinity in the process of adjusting the salinity of the seawater test solution The amount of seawater is adaptively adjusted, and the control liquid level of the seawater test solution in the test chamber is adjusted in real time at each stage of preparation to obtain high salinity preparation accuracy and short salinity preparation time.

Claims (1)

1. a PLC fuzzy self-adaption seawater salinity test unit, it is characterized in that: this test unit is by seawater salinity test platform and PLC salinity composition of the control system, described seawater salinity test platform comprises chamber (1), mother liquor tank (2) and accumulator tank (3), mother liquor tank (2) is delivered to seawater in chamber (1) by seawater intake line, seawater testing liquid in chamber (1) is delivered to accumulator tank (3) by reclaim line, recovery liquid in accumulator tank (3) route seawater circulation line after outlet pipeline flows out is delivered to mother liquor tank (2), another road emits through discharge pipe, described seawater intake line, reclaim line, on seawater circulation line and discharge pipe, be respectively equipped with salt water solenoid valve (7), water-drainage solenoid valve (8), seawater recovery pump (5) and discharge solenoid valve (9), described chamber is connected with freshwater input pipeline on (1), on freshwater input pipeline, be provided with fresh water solenoid valve (6), in chamber (1), be also provided with seawater testing liquid closed circuit, on seawater testing liquid closed circuit, be provided with sea water circulating pump (4),

Described PLC salinity control system comprises industrial computer (11), PLC control module (10), I/O drive interface module (20), sensor interface module, salinity sensor and liquid level sensor, the host computer that industrial computer (11) is described test unit, and carry out data communication with PLC control module (10), salinity sensor and liquid level sensor are for detection of chamber (1), salinity and liquid level information in mother liquor tank (2) and accumulator tank (3), the signal output part of salinity sensor and liquid level sensor is connected with the signal input part of sensor interface module, the signal output part of sensor interface module is connected with the analog input port of PLC control module (10), the I/O control port of PLC control module (10) is connected with the I/O control inputs port of I/O drive interface module (20), the I/O control output end mouth of I/O drive interface module (20) respectively with sea water circulating pump (4), seawater recovery pump (5), fresh water solenoid valve (6), salt water solenoid valve (7), water-drainage solenoid valve (8) is connected with the drive end of discharge solenoid valve (9).

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