Automatic chlorine demand detection system and method

Abstract

The invention discloses an automatic chlorine demand detection system and method. The automatic chlorine demand detection system at least comprises but is not limited to a sample injection module, a reaction module, a detection module and a control and display module, the reaction module is connected with the sample injection module, at least one reaction tank is arranged in the reaction module, the detection module is connected with the reaction module, and the control and display module is respectively connected with the sample injection module, the reaction module and the detection module; according to the scheme, the sample injection module is used for sample injection control of a sample water body, the sample water body enters the reaction module through a pipeline, the sample water body reacts with a medicament, the reacted water body enters the detection module, the detection module detects the reacted water body, and finally detected data is displayed in the control and display module. And the control and display module controls parts in each module at the same time, automatically calculates and processes related data according to an algorithm, and finally realizes automatic data acquisition.

Description

Technical Field

[0001] The present invention relates to the technical field of water quality detection, and in particular to a system and method for automatically detecting chlorine demand. Background Art

[0002] In the field of water treatment, ensuring water quality is safe and hygienic is of vital importance. Chlorination disinfection is a key link in tap water production and plays a decisive role in killing harmful microorganisms in water. However, the quality of source water is complex and changeable due to many factors such as season, climate, geographical environment and human activities. In the process of tap water production, this situation requires that the amount of chlorine required for water treatment in the chlorination disinfection link must be adjusted in real time according to the changes in the quality of the source water, especially during the period of ammonia nitrogen pollution, when the source water contains a rich variety of substances and complex components, and the chlorine-nitrogen reaction ratio is difficult to determine.

[0003] At present, in the actual tap water production process, the amount of chlorine disinfectant added is more dependent on the results of artificial chlorination experiments to calculate the chlorine demand, and then the chlorine addition is adjusted in combination with the display value of the outlet residual chlorine meter. However, this method has many disadvantages. Manual detection is discontinuous, there are detection intervals, and it is easy to introduce errors and low efficiency. The detection data of the outlet residual chlorine meter has a time lag and cannot reflect the actual chlorine demand of the current water quality in a timely manner. It may lead to insufficient chlorine addition affecting water quality safety, or excessive chlorine addition causing waste of resources and the production of harmful disinfection by-products, threatening human health and the environment.

[0004] The existing water treatment chlorine demand detection and adjustment methods are difficult to meet the increasingly stringent water quality requirements and the needs of efficient production. There is an urgent need for a method and system that can detect chlorine demand in real time, accurately and automatically to optimize the water treatment process and ensure water quality safety and production efficiency. In the field of chlorine demand detection, in order to achieve more accurate, efficient and reliable detection goals, there are still the following technical difficulties.

[0005] 1. Accuracy of water sample injection and reagent dosage:

[0006] In the water sampling process, the accuracy, continuity and representativeness of the injection volume are difficult to guarantee. Given the complex and variable characteristics of source water, it may contain impurities or particles, which can easily cause the injection pump to be blocked or the injection volume to fluctuate, which will have a negative impact on the accuracy and continuity of the test. Furthermore, the material selection and design planning of the injection pipeline may not be able to effectively avoid the residue and cross contamination of the water sample, thereby interfering with the subsequent test results.

[0007] The actual amount of sodium hypochlorite contained in the added reagent is difficult to guarantee. The reaction reagent in the chlorine demand detection is sodium hypochlorite, which is unstable and easily decomposed by light. As the reagent is placed over time, its concentration decreases, which directly affects the calculation results of the automatic chlorine demand detection. In addition, the added amount is milliliters, and the small amount added makes it more difficult to control the accuracy. Therefore, the detection and accurate addition of sodium hypochlorite concentration in the automatic chlorine demand detection is particularly critical.

[0008] 2. Chlorination reaction sufficiency:

[0009] The water quality reaction system faces the dilemma of difficult to accurately control the reaction conditions. For example, the substances in the water sample are changeable and uncertain, and the required reagent dosage and reaction time are different. It is difficult to determine the dosage of the reaction reagent according to the changes in the water sample, and the accuracy of the reaction time is also difficult to guarantee, which may cause insufficient or excessive reaction with the substances in the water sample; in addition, uneven stirring of the reaction tank will also affect the reaction effect, and then produce errors in the chlorine demand detection.

[0010] 3. Adaptability to different water samples:

[0011] Due to different water systems and seasons, the reducing substances, microorganisms, algae and other substances in water samples are different, and the requirements for various parameters of automatic chlorination reaction are also different, such as pre-detection time, reaction time, sodium hypochlorite dosage, etc. In actual production testing, according to different production conditions, users will also have different requirements for automatic detection of chlorine demand. For example, if the water sample is reservoir water with stable water quality, the user pursues faster automatic detection. Therefore, the reaction time just meets the requirement of "the determination of free chlorine index in the "Sanitary Standard for Drinking Water" should ensure that the chlorination reaction time is greater than 30 minutes". Therefore, the parameters of the automatic detection method should be adjustable to meet actual detection needs.

[0012] 4. Shorten the water sample injection cycle and increase the frequency of periodic water sample testing: When the reaction module is performing a chlorination reaction, the reaction tank is occupied and water sampling cannot be performed during the reaction. The conditions for water sample injection must be met after the reaction tank is completed and cleaned. This prolongs the water injection test cycle and reduces the frequency of water sample testing. Therefore, it is necessary to find a method to shorten the water sample injection cycle and increase the detection frequency.

[0013] 5. Data processing:

[0014] The data processing system has defects in the accuracy and adaptability of the algorithm. Complex water quality conditions may cause abnormal fluctuations in data, and the existing algorithm may not be able to effectively identify and process these abnormal values, thus affecting the final chlorine demand calculation results. At the same time, the data storage and management mode may lack efficiency, which is not conducive to the rapid retrieval and long-term retention of data.

[0015] In summary, the existing automatic detection of chlorine demand has technical difficulties to varying degrees, and it is urgent to find a suitable automatic detection method and a reliable, accurate and easy-to-use detection device. Summary of the invention

[0016] The object of the present invention is to provide a system and method for automatically detecting chlorine demand in view of the above-mentioned deficiencies, so as to solve the problems in the prior art of low accuracy of water sample injection and reagent dosage, inability to fully react chlorination reaction under different water samples, inability to adapt to different water samples, low frequency of periodic detection of water samples, inability to identify and process abnormal data, and inefficient data storage and management mode.

[0017] The present invention is achieved through the following scheme:

[0018] A chlorine demand automatic detection system includes at least but not limited to a sampling module, a reaction module, a detection module and a control and display module; the reaction module is connected to the sampling module, at least one reaction tank is arranged in the reaction module, the detection module is connected to the reaction module, and the control and display module is respectively connected to the sampling module, the reaction module and the detection module.

[0019] Based on the structure of the above-mentioned automatic chlorine demand detection system, the injection module includes a liquid inlet switching valve, a liquid inlet pump and a reagent giving component; one end of the liquid inlet switching valve is respectively connected to the pure water inlet pipe and the raw water inlet pipe, and the other end is connected to the liquid inlet pump, and the liquid inlet pump and the reagent giving component are connected to the reaction module.

[0020] Based on the structure of the above-mentioned automatic chlorine demand detection system, the reaction module includes a reaction tank, a pre-test tank and a detection tank, and the reaction tank is connected to the pre-test tank and the detection tank through a first pipeline and a second pipeline respectively; the liquid inlet end of the reaction tank is connected to the agent giving component and the liquid inlet pump respectively, and the pre-test tank and the detection tank are connected to the detection module through pipelines.

[0021] Based on the structure of the above-mentioned automatic chlorine demand detection system, the detection module includes a detection switching valve, a filter component and a residual chlorine detection unit; the detection switching valve is connected to the pre-test tank and the detection tank respectively, the detection switching valve is connected to the filter component, and the filter component is connected to the residual chlorine detection unit; a stirring component is arranged at the top position of the reaction tank, at least two liquid level sensors are arranged on the inner wall of the reaction tank, a pre-test liquid inlet valve is arranged on the first pipeline, and a detection liquid inlet valve is arranged on the second pipeline; a drain valve is also arranged at the bottom of the reaction tank, and a pre-test vent valve and a detection vent valve are also arranged at the bottom of the pre-test tank and the detection tank; the control and display module includes a controller and a touch screen; the controller is electrically connected to the components in the injection module, the reaction module and the detection module, and the touch screen is connected to the controller.

[0022] This solution provides a method for automatically detecting chlorine demand, which comprises the following steps:

[0023] S1: Take samples, start the liquid inlet pump to feed raw water into the reaction tank, and start the reagent setting component to add reagents into the reaction tank;

[0024] S2: Reaction: After a short-time chlorination reaction, the chlorine consumption of the water body is pre-judged. If the residual chlorine is sufficient, it will automatically enter the detection tank for residual chlorine detection after sufficient reaction; if the residual chlorine is insufficient, it will automatically add the drug for the second time, and then enter the detection tank for residual chlorine detection after sufficient reaction;

[0025] S3: Detection: Detect the free residual chlorine index through the residual chlorine detection unit;

[0026] S4: Calculation. By collecting multiple sets of data and analyzing and comparing them, the calculation module is capable of automatically identifying and eliminating abnormal data, automatically calculating and selecting normal data within the measurement period and displaying it on the human-computer interaction interface; repeat S1 to S4 as needed.

[0027] In S1, the specific steps of sampling are: start the water inlet peristaltic pump to feed V1ml of raw water into the reaction tank, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V2ml into the reaction tank;

[0028] In S2, the specific steps of the reaction are: start the stirring component to fully mix the solution in the reaction tank; after T0 minutes, put V3ml of the mixed solution into the pre-test tank and detect the residual chlorine value Kmg / l of the mixed solution; judge the K value;

[0029] When K>m, after T1min, open the test liquid inlet valve and put the solution into the test tank;

[0030] When n<K<m, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V4ml into the reaction tank, and after T2min, open the detection liquid inlet valve to put the solution into the detection tank;

[0031] When K<n, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V5ml into the reaction tank. After T3min, open the detection liquid inlet valve to put the solution into the detection tank.

[0032] In S3, the specific steps of detection are: detecting the free residual chlorine index through a residual chlorine detection unit;

[0033] When K>m, after T1min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K1mg / l;

[0034] When n<K<m, after T2min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K2mg / l;

[0035] When K<n, after T3min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K3mg / l, T1<T2<T3; in S4, the specific steps of calculation are to obtain the expression of raw water chlorine demand according to steps S1, S2, and S3:

[0036] C=[1000*a*V2-K1(V1+V2)] / V1K>m

[0037] C=[1000*a*(V2+V4)-K2(V1+V2+V4)] / V1n<K<m

[0038] C=[1000*a*(V2+V5)-K3(V1+V2+V5)] / V1K<n

[0039] Wherein, C is the chlorine demand of raw water, in mg / l; a is the concentration of sodium hypochlorite, in mg / l; V2 is the initial dosage of sodium hypochlorite, in ml; V4 is the secondary dosage of sodium hypochlorite when n<K<m, in ml; V5 is the secondary dosage of sodium hypochlorite when K<n, in ml; K is the residual chlorine of the solution during pre-test, in mg / l; K1 is the residual chlorine value of the solution in the test tank when K≥m, in mg / l; K2 is the residual chlorine value of the solution in the test tank when n<K<m, in mg / l; K3 is the residual chlorine value of the solution in the test tank when K<n, in mg / l; m and n are constants, and m>n>0.

[0040] In S4, a drug concentration calibration process is also provided, which includes the following steps:

[0041] S41: Take a sample, open the liquid inlet switching valve, start the water inlet peristaltic pump to feed V1ml of pure water into the reaction tank, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V2ml into the reaction tank;

[0042] S42: Reaction, start the mixing and stirring component to fully mix the solution in the reaction tank; after T1 minute, put V3ml of the mixed solution into the pre-inspection tank;

[0043] S43: Detection, through the residual chlorine detection unit, after T1min, the residual chlorine detection unit measures the residual chlorine value of the solution to be K1mg / l;

[0044] S44: Data calculation, according to steps S41, S42, S43, the sodium hypochlorite concentration expression is obtained:

[0045] a1=(V1+V2)*K1 / (1000*V2)

[0046] Among them, a1 is the actual sodium hypochlorite, in mg / ml; V1 is the volume of pure water, in ml; V2 is the amount of sodium hypochlorite added, in ml; K1 is the residual chlorine value of the solution in the pre-test tank, in mg / l.

[0047] The present solution also provides a method for automatically detecting chlorine demand, which includes a plurality of reaction tanks, wherein the input ends of the plurality of reaction tanks are connected to the sampling module, and the output ends of the plurality of reaction tanks are respectively connected to the pre-test tank and the reaction tank; the method includes the following steps:

[0048] S1: Take samples in sequence, start the liquid inlet pump to feed raw water into the designated reaction tank, and start the reagent setting component to add sodium hypochlorite into the designated reaction tank;

[0049] S2: Reaction: After a short-time chlorination reaction, the chlorine consumption of the water body is pre-judged. If the residual chlorine is sufficient, it will automatically enter the detection tank for residual chlorine detection after sufficient reaction; if the residual chlorine is insufficient, it will automatically add the drug for the second time, and then enter the detection tank for residual chlorine detection after sufficient reaction;

[0050] S3: Detection: Detect the free residual chlorine index through the residual chlorine detection unit; after setting the interval time according to the number of reaction tanks N and the water pollution situation, start the sampling operation of the next-level reaction tank, where N is an integer greater than 1;

[0051] S4: Calculation. Through analysis and comparison, the calculation module is capable of automatically identifying and eliminating abnormal data, automatically selecting normal data within the measurement cycle and displaying it on the human-computer interaction interface; and repeating S1 to S4 as needed.

[0052] In S3, the specific steps of detection are: detecting the free residual chlorine index through a residual chlorine detection unit;

[0053] When K>m, after T1min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K1mg / l;

[0054] When n<K<m, after T2min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K2mg / l;

[0055] When K<n, after T3min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K3mg / l;

[0056] The time for the second injection of the secondary reaction tank is set by the following method;

[0057] When K>m, after (T0+T1) / Nmin, the next-level reaction tank is sampled, the water inlet peristaltic pump and the switching valve are started to feed V1ml of raw water into the reaction tank, and the micro-injection pump and the switching valve are started to add sodium hypochlorite with a concentration of amg / ml and a volume of V2ml into the reaction tank;

[0058] When n<K<m, after (T0+T2) / Nmin, the next-level reaction tank is sampled, the water inlet peristaltic pump and the switching valve are started to feed V1ml of raw water into the reaction tank, and the micro-injection pump and the switching valve are started to add sodium hypochlorite with a concentration of amg / ml and a volume of V2ml into the reaction tank;

[0059] When K<n, after (T0+T3) / Nmin, the next-level reaction tank is sampled, the water inlet peristaltic pump and the switching valve are started to feed V1ml of raw water into the reaction tank, and the micro-injection pump and the switching valve are started to add sodium hypochlorite with a concentration of amg / ml and a volume of V2ml into the reaction tank.

[0060] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0061] 1. In this scheme, the injection module is used for the injection control of the sample water. The sample water enters the reaction module through the pipeline to make the sample water react with the reagent. The water after the reaction enters the detection module, and the detection module detects it. The final data after detection is displayed in the control and display module. The control and display module controls the components in each module at the same time, and finally realizes automatic data collection.

[0062] 2. Through this solution, in terms of detection accuracy, through advanced detection equipment and meticulous detection methods, the chlorine demand in water samples can be accurately measured, the error can be greatly reduced, and accurate data support can be provided for water treatment;

[0063] 3. In terms of real-time performance, the detector can realize continuous periodic detection and real-time monitoring, timely reflect the dynamic changes of water quality, and provide a scientific and accurate basis for determining the amount of chlorine added. On the one hand, it avoids the risk of water production caused by discontinuous manual detection data. On the other hand, the continuity and accuracy of the detection data are more conducive to the precise control of the amount of chlorine added, avoiding substandard water quality due to insufficient chlorination or unnecessary cost waste and increase of disinfection by-products due to excessive chlorination;

[0064] 4. In terms of automation, the entire process from water sample collection, testing and analysis to data processing and result output is automated, reducing human intervention. This not only improves work efficiency but also reduces the impact of human errors.

[0065] 5. The device adopts modular design, and each module is connected by a quick-pull connector, which is convenient for addition and removal. One or more reaction tank modules can be added as needed to increase the detection frequency exponentially and detect water quality changes in a timely manner.

[0066] 6. This solution has good adaptability to complex water quality conditions. It can accurately detect the chlorine demand of water samples from various water sources and with different pollution levels, and is not significantly affected by factors such as impurities and interfering substances in the water samples; the intelligent data processing and analysis functions can effectively manage and deeply mine a large amount of test data, providing a strong basis for optimizing water treatment processes and predicting water quality change trends;

[0067] 7. At the same time, the long-term stability and reliability of the detector have been significantly improved, reducing maintenance costs and equipment failure rates, ensuring that accurate test results can be continuously and stably provided during long-term operation.

[0068] 8. The reaction system is equipped with a two-stage chlorination program. The chlorination amount can be adjusted in real time according to the changes in the water body. When the chlorine consumption is low, only the first-stage chlorination can be started to reduce the cycle time. When the chlorine consumption increases, the second-stage chlorination can be started, and the reaction time can be adjusted according to the type of pollution, providing data basis for the water plant's emergency decision-making. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a schematic diagram of the structure of embodiment 1 of the invention;

[0070] Figure 2 It is a schematic diagram of the structure of multiple reaction tanks in the invention;

[0071] Figure 3 A control flow diagram of an automatic chlorine demand detection device is invented;

[0072] Figure 4 A schematic diagram of the control flow of reagent calibration for an automatic chlorine demand detection device is invented;

[0073] Figure numerals: 1. Sampling module; 2. Reaction module; 3. Detection module; 4. Control and display module; 11. Liquid inlet switching valve; 12. Liquid inlet pump; 13. Drug dosing component; 14. Pure water inlet pipe; 15. Raw water inlet pipe; 131. Drug bottle; 132. Micro injection pump; 21. Reaction tank; 22. Pre-test tank; 23. Detection tank; 24. First pipeline; 25. Second pipeline; 26. Stirring component; 27. Liquid level sensor; 28. Pre-test liquid inlet valve; 29. ​​Detection liquid inlet valve; 210. Drain valve; 211. Pre-test vent valve; 212. Detection vent valve; 31. Detection switching valve; 32. Filter component; 33. Residual chlorine detection unit. DETAILED DESCRIPTION

[0074] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0075] Any feature disclosed in this specification (including any additional claims and abstract), unless otherwise stated, may be replaced by other equivalent or alternative features having similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0076] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a predetermined direction, be constructed and operated in a predetermined direction, and therefore cannot be understood as a limitation on the present invention.

[0077] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0078] Example 1

[0079] like Figure 1 The present invention provides a technical solution:

[0080] A chlorine demand automatic detection system, which at least includes but is not limited to a sampling module 1, a reaction module 2, a detection module 3 and a control and display module 4; the reaction module 2 is connected to the sampling module 1, at least one reaction tank 21 is arranged in the reaction module 2, the detection module 3 is connected to the reaction module 2, and the control and display module 4 is respectively connected to the sampling module 1, the reaction module 2, and the detection module 3.

[0081] Based on the above structure, the injection module 1 is used for the injection control of the sample water body. The sample water body enters the reaction module 2 through the pipeline, so that the sample water body reacts with the reagent. The water body after the reaction enters the detection module 3, and the detection module 3 detects it. The final data after detection is displayed in the control and display module 4. The control and display module 4 controls the components in each module at the same time, and finally realizes automatic data collection.

[0082] As an example, the injection module 1 may include a liquid inlet switching valve 11, a liquid inlet pump 12 and a reagent dosing component 13; one end of the liquid inlet switching valve 11 is respectively connected to the pure water inlet pipe 14 and the raw water inlet pipe 15, and the other end is connected to the liquid inlet pump 12, and the liquid inlet pump 12 and the reagent dosing component 13 are connected to the reaction module 2.

[0083] Based on the above structure, the liquid inlet can be switched through the liquid inlet switching valve 11 to achieve pure water inlet or raw water inlet according to actual needs. At the same time, the reagent giving component 13 is used to add the reagent to the reaction module 2 to achieve the reaction of the raw water or the measurement and calibration of the reagent.

[0084] As an example, the drug administering component 13 may include a drug bottle 131 and a micro-injection pump 132; the drug bottle 131 is connected to the micro-injection pump 132, and the micro-injection pump 132 is connected to the reaction module 2; the liquid inlet pump 12 may be a peristaltic pump; and the liquid inlet switching valve 11 may be an electromagnetic tube clamp valve.

[0085] Based on the above structure, this solution adopts a high-precision, corrosion-resistant peristaltic pump to draw water, which can achieve high-precision water intake. At the same time, the liquid inlet switching valve 11 of this solution adopts a chemically corrosion-resistant, long-life electromagnetic tube clamp valve; the liquid flow direction is controlled by squeezing or loosening the hose, avoiding the leakage and inaccurate control problems that may occur in traditional valves; the sampling pipeline uses a silicone tube made of high-quality inert material, and its inner wall has been specially treated and is extremely smooth, thereby greatly reducing the probability of water sample residue and cross contamination; the drug extraction adopts a high-precision, corrosion-resistant, long-life micro-injection pump 132, which can perform micro-precision drug extraction.

[0086] As an example, the reaction module 2 may include a reaction tank 21, a pre-test tank 22 and a detection tank 23, and the reaction tank 21 is connected to the pre-test tank 22 and the detection tank 23 through a first pipeline 24 and a second pipeline 25, respectively; the liquid inlet end of the reaction tank is respectively connected to the drug giving component 13 and the liquid inlet pump 12, and the pre-test tank 22 and the detection tank 23 are connected to the detection module 3 through pipelines.

[0087] Based on the above structure, the reaction tank 21 is used to react the original liquid or pure water with the reagent. The liquid after the reaction of the original liquid and the reagent is first passed into the pre-test tank 22 to preliminarily judge whether the reagent in the reaction tank 21 is sufficient. According to the feedback in the pre-test tank 22, the reagent is added for the second time to make the reaction complete. Then, the liquid after the reaction is complete is passed into the detection tank 23 for temporary storage, and is continuously transported to the detection module 3 for detection as needed.

[0088] As an example, a stirring assembly 26 can be provided at the top position of the reaction tank 21, at least two liquid level sensors 27 can be provided on the outer wall of the reaction tank 21, a pre-inspection liquid inlet valve 28 can be provided on the first pipeline 24, and a detection liquid inlet valve 29 can be provided on the second pipeline 25; a drain valve 210 can also be provided at the bottom of the reaction tank 21, and a pre-inspection drain valve 211 and a detection drain valve 212 can also be provided at the bottom of the pre-inspection tank 22 and the detection tank 23.

[0089] Based on the above structure, the reaction between the reagent and the raw water can be accelerated by setting a stirring component 26. By using at least two liquid level sensors 27, the liquid level of the reaction liquid can be detected at different liquid level positions, so as to accurately calculate the amount of reaction liquid transported outward. It can efficiently and accurately determine the amount of output reaction liquid through a simple device. By setting a pre-inspection liquid inlet valve 28 and a detection liquid inlet valve 29, the on-off of the pipeline in which they are located can be accurately controlled. By setting a pre-inspection drain valve 211 and a detection drain valve 212, unused waste liquid can be discharged to ensure the accuracy of the data.

[0090] In this scheme, when the raw water reaches a certain height and the reagent is added, it is used for mixing and stirring to make it fully react; one end of the reaction tank 21 is connected to the water inlet peristaltic pump and the micro-injection pump 132, and the other end is connected to the pre-test liquid inlet valve 28 and the detection liquid inlet valve 29, which is used as the reaction place of the raw water and the reagent; the liquid level sensor 27 is installed on the reaction tank 21 to detect the liquid level and to control the switch of the pre-test tank 22 liquid inlet valve; the reaction tank 21 drain valve 210 is installed at the bottom of the reaction tank 21 to empty the remaining reaction liquid and flushing water; the pre-test liquid inlet valve 28 is connected to the reaction tank 21 at one end and to the pre-test tank 22 at the other end, and is used to drain the pre-reaction liquid in the reaction tank 21. The pre-inspection tank 22 is respectively connected to the pre-inspection liquid inlet valve 28 and the switching valve of the residual chlorine detection unit 33 in the detection system, and is used to store the pre-reaction liquid; the pre-inspection vent valve 211 is installed at the bottom of the pre-inspection tank 22, and is used to vent the remaining pre-reaction liquid; the detection liquid inlet valve 29 is connected to the reaction tank 21 at one end and to the detection tank 23 at the other end, and is used to transport the reaction liquid that has completely reacted in the reaction tank 21 to the detection tank 23; the detection tank 23 is respectively connected to the detection liquid inlet valve 29 and the switching valve of the residual chlorine detection unit 33, and is used to store the reaction liquid; the detection vent valve 212 is installed at the bottom of the detection tank 23, and is used to vent the remaining reaction liquid;

[0091] In the reaction module 2 of this embodiment, the container is made of high-quality acrylic material, which has excellent chemical stability and good transparency, and has a capacity scale display, which is convenient for observing the reaction; the mixing and stirring component 26, whose stirring speed can be flexibly adjusted by the controller, and adopts a two-stage paddle to ensure that the reaction liquid is fully and evenly mixed; the venting and switching valves are chemically resistant and have a long life electromagnetic pipe clamp valve. The flow direction of the liquid is controlled by squeezing or loosening the hose, avoiding the leakage and inaccurate control problems that may occur in traditional valves; the connecting pipeline uses a silicone tube made of high-quality inert material, and its inner wall is specially treated and extremely smooth, thereby greatly reducing the probability of water sample residue and cross contamination.

[0092] As an example, the detection module 3 may include a detection switching valve 31, a filter component 32 and a residual chlorine detection unit 33; the detection switching valve 31 is connected to the pre-inspection tank 22 and the detection tank 23 respectively, the detection switching valve 31 is connected to the filter component 32, and the filter component 32 is connected to the residual chlorine detection unit 33.

[0093] Based on the above structure, one end of the detection switching valve 31 is connected to the pre-detection tank 22 and the detection tank 23, and the other end is connected to the filter group, which is used to control the switching of the reaction liquid in the pre-detection tank 22 and the reaction liquid in the detection tank 23, and transport them to the residual chlorine detection unit 33; one end of the filter component 32 is connected to the switching valve of the residual chlorine detection unit 33, and the other end is connected to the residual chlorine detection unit, which is used to filter impurities in the reaction liquid; the residual chlorine detection unit 33 is connected to the filter component 32 through the liquid inlet pipe, and is used to detect the residual chlorine in the reaction liquid.

[0094] The detection module 3 in this solution uses a high-precision, wide-range residual chlorine detection unit 33 for residual chlorine detection; at the same time, a high-molecular, acid-resistant filter component 32 is used to effectively filter impurities in the raw water; the switching valve uses a chemically resistant, long-life electromagnetic pipe clamp valve. The flow direction of the liquid is controlled by squeezing or loosening the hose, avoiding the leakage and inaccurate control problems that may occur in traditional valves; the connecting pipeline uses a silicone tube made of high-quality inert material, and its inner wall is specially treated and extremely smooth, thereby greatly reducing the probability of water sample residue and cross contamination.

[0095] As an example, the control and display module 4 includes a controller and a touch screen; the controller is electrically connected to the components in the injection module 1, the reaction module 2, and the detection module 3, and the touch screen is connected to the controller for controlling the operation and data calculation of the entire device; the touch screen is used for data display and related parameter settings, etc.

[0096] Based on the above structure, the control and display module 4 in this solution adopts a high-performance industrial processor, multiple communication protocols, and a display system with touch function, which has friendly human interaction. It can automatically complete the whole process of sample solution collection, reagent addition, reaction, analysis, data processing, etc., without human intervention, and fully automated control.

[0097] Example 2

[0098] like Figure 3-4 As shown, based on the system of the above embodiment 1, this embodiment provides a method for automatically detecting chlorine demand, which includes the following steps:

[0099] S1: Take samples, start the liquid inlet pump to feed raw water into the reaction tank, and start the reagent setting component to add sodium hypochlorite into the reaction tank;

[0100] S2: Reaction: After a short-time chlorination reaction, the chlorine consumption of the water body is pre-judged. If the residual chlorine is sufficient, it will automatically enter the detection tank for residual chlorine detection after sufficient reaction; if the residual chlorine is insufficient, it will automatically add the drug for the second time, and then enter the detection tank for residual chlorine detection after sufficient reaction;

[0101] S3: Detection: Detect the free residual chlorine index through the residual chlorine detection unit;

[0102] S4: Calculation. Through analysis and comparison, the calculation module is capable of automatically identifying and eliminating abnormal data, automatically selecting normal data within the measurement cycle and displaying it on the human-computer interaction interface; and repeating S1 to S4 as needed.

[0103] In S1, the specific steps of sampling are: start the water inlet peristaltic pump to feed V1ml of raw water into the reaction tank, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V2ml into the reaction tank;

[0104] In S2, the specific steps of the reaction are: start the stirring component to fully mix the solution in the reaction tank; after 15 minutes, put V3ml of the mixed solution into the pre-test tank and detect the residual chlorine value Kmg / l of the mixed solution; judge the K value;

[0105] When K>m, after T1min, open the test liquid inlet valve and put the solution into the test tank;

[0106] When n<K<m, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V4ml into the reaction tank, and after T2min, open the detection liquid inlet valve to put the solution into the detection tank;

[0107] When K<n, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V5ml into the reaction tank. After T3min, open the detection liquid inlet valve to put the solution into the detection tank.

[0108] In this scheme, the chlorine consumption in the liquid of the initial reaction is judged through the pre-test tank, and a specified amount of reagent is added to the reaction tank again according to different chlorine consumption levels. Since the amount of raw water entering the pre-test tank can be accurately determined by two liquid level detectors, the amount of secondary reagent added can also be obtained, and the chlorine demand of the raw water can be accurately obtained through calculation.

[0109] In S3, the specific steps of the detection are: using a residual chlorine detection unit to detect the free residual chlorine index using the N, N-diethyl-p-phenylenediamine spectrophotometric method specified in the national standard;

[0110] When K>m, after T1min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K1mg / l;

[0111] When n<K<m, after T2min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K2mg / l;

[0112] When K<n, after T3min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K3mg / l, T1<T2<T3; in S4, the specific steps of calculation are to obtain the expression of raw water chlorine demand according to steps S1, S2, and S3:

[0113] C=[1000*a*V2-K1(V1+V2)] / V1K>m;

[0114] C=[1000*a*(V2+V4)-K2(V1+V2+V4)] / V1n<K<m;

[0115] C=[1000*a*(V2+V5)-K3(V1+V2+V5)] / V1K<n;

[0116] Where, C is the chlorine requirement of raw water, in mg / l, a is the concentration of sodium hypochlorite, in mg / ml,

[0117] V2 is the initial amount of sodium hypochlorite added, in ml.

[0118] V4 is the secondary addition amount of sodium hypochlorite when n<K<m, unit is ml;

[0119] V5 is the secondary addition amount of sodium hypochlorite when K < n, in ml.

[0120] K is the residual chlorine in the solution during pre-test, in mg / l;

[0121] K1 is the residual chlorine value of the solution in the test tank when K≥m, in mg / l;

[0122] K2 is the residual chlorine value of the test tank solution when n<K<m, in mg / l;

[0123] K3 is the residual chlorine value of the solution in the detection tank when K < n, in mg / l;

[0124] m, n are constants, and m>n>0.

[0125] As an example, a drug concentration calibration process may also be provided in S4, which includes the following steps:

[0126] S41: Sampling, through micro-flow control technology, to ensure the precise addition of pure water and medicine.

[0127] Open the liquid inlet switching valve, start the water inlet peristaltic pump to feed pure water V1ml into the reaction tank, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V2ml into the reaction tank;

[0128] S42: Reaction, start the mixing and stirring component to fully mix the solution in the reaction tank; after T1 minute, put V3ml of the mixed solution into the pre-inspection tank;

[0129] S43: Detection: Through the residual chlorine detection unit, the free residual chlorine index is detected by the N, N-diethyl-p-phenylenediamine spectrophotometric method specified in the national standard;

[0130] After T1min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K1mg / l;

[0131] S44: Data calculation, through analysis and comparison, the calculation module has the ability to automatically identify and exclude abnormal data, and automatically select normal data within the measurement period.

[0132] According to steps S41, S42, and S43, the sodium hypochlorite concentration expression is obtained:

[0133] a1=(V1+V2)*K1 / (1000*V2);

[0134] Wherein, a1 is the actual sodium hypochlorite, in mg / ml;

[0135] V1 is the volume of pure water, in ml;

[0136] V2 is the amount of sodium hypochlorite added, in ml;

[0137] K1 is the residual chlorine value of the pre-test tank solution, in mg / l;

[0138] Since it is impossible to confirm the dosage accuracy of the existing technology, the reaction reagent in the chlorine demand detection is sodium hypochlorite, which is unstable and easily decomposed by light. As the reagent is placed over time, its concentration decreases, which directly affects the automatic detection and calculation results of chlorine demand. Therefore, this method can periodically start the reagent concentration calibration process to ensure the accuracy of the reagent concentration, thereby obtaining accurate raw water chlorine demand data.

[0139] The method for detecting chlorine demand in this scheme is based on the principle of chlorination reaction, which can truly simulate the actual production situation, and the chlorine demand detection is more accurate;

[0140] The method for detecting chlorine demand in this scheme pre-judges the chlorine consumption of the water body through a short-time chlorination reaction. If the residual chlorine is sufficient, the water sample automatically enters the detection tank for residual chlorine detection; if the residual chlorine is insufficient, chlorine is automatically added for a second time, and after sufficient reaction, it enters the detection tank and finally detects the residual chlorine to ensure accurate chlorine demand detection;

[0141] The method for detecting chlorine demand in this scheme includes a one-key calibration function for reagent concentration. By calibrating the reagent concentration and transmitting the data to the system in real time, when the concentration of the reagent volatilization exceeds the set value, an alarm is issued in time to remind the replacement of the reagent, thereby reducing the impact of reagent volatilization and concentration reduction on the measurement, and further improving the accuracy of chlorine demand detection;

[0142] The method for detecting chlorine demand in this scheme can manually set relevant parameters according to specific circumstances. It has good adaptability and can accurately detect the chlorine demand of water samples from various water sources and with different pollution levels, and is not limited by impurities in the water samples and reaction time.

[0143] Example 3

[0144] like Figure 2 As shown, based on the system of the above embodiment 1, the system can be provided with multiple reaction tanks to shorten the time interval for detecting the raw water chlorine demand data. The input ends of the multiple reaction tanks are all connected to the sampling module, and the output ends of the multiple reaction tanks are respectively connected to the pre-test tank and the reaction tank.

[0145] This embodiment provides a method for automatically detecting chlorine demand, which comprises the following steps:

[0146] S1: Take samples in sequence, start the liquid inlet pump to feed raw water into the designated reaction tank, and start the reagent setting component to add sodium hypochlorite into the designated reaction tank;

[0147] S2: Reaction: After a short-time chlorination reaction, the chlorine consumption of the water body is pre-judged. If the residual chlorine is sufficient, it will automatically enter the detection tank for residual chlorine detection after sufficient reaction; if the residual chlorine is insufficient, it will automatically add the drug for the second time, and then enter the detection tank for residual chlorine detection after sufficient reaction;

[0148] S3: Detection, detecting the free residual chlorine index through the residual chlorine detection unit; after a preset time is set according to the number of reaction tanks, the Nth level detection operation is started, N is an integer greater than 1; after an interval time is set according to the number of reaction tanks N and the water pollution situation, the next level reaction tank sampling operation is started, N is an integer greater than 1;

[0149] S4: Calculation. Through analysis and comparison, the calculation module is capable of automatically identifying and eliminating abnormal data, automatically selecting normal data within the measurement cycle and displaying it on the human-computer interaction interface; and repeating S1 to S4 as needed.

[0150] In S1, the specific steps of sampling are: start the water inlet peristaltic pump to feed V1ml of raw water into the reaction tank, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V2ml into the reaction tank;

[0151] In S2, the specific steps of the reaction are: start the stirring component to fully mix the solution in the reaction tank; after T0 minutes, put V3ml of the mixed solution into the pre-test tank, and detect the residual chlorine value Kmg / l of the mixed solution.

[0152] When K>m, after T1min, open the test liquid inlet valve and put the solution into the test tank;

[0153] When n<K<m, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V4ml into the reaction tank, and after T2min, open the detection liquid inlet valve to put the solution into the detection tank;

[0154] When K<n, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V5ml into the reaction tank. After T3min, open the detection liquid inlet valve to put the solution into the detection tank.

[0155] In this scheme, the chlorine consumption in the liquid of the initial reaction is judged through the pre-test tank, and a specified amount of reagent is added to the reaction tank again according to different chlorine consumption levels. Since the amount of raw water entering the pre-test tank can be accurately determined by two liquid level detectors, the amount of secondary reagent added can also be obtained, and the chlorine demand of the raw water can be accurately obtained through calculation.

[0156] In S3, the specific steps of the detection are: using a residual chlorine detection unit to detect the free residual chlorine index using the N, N-diethyl-p-phenylenediamine spectrophotometric method specified in the national standard;

[0157] When K>m, after T1min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K1mg / l;

[0158] When n<K<m, after T2min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K2mg / l;

[0159] When K<n, after T3min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K3mg / l, T1<T2<T3; in S4, the specific steps of calculation are to obtain the expression of raw water chlorine demand according to steps S1, S2, and S3:

[0160] C=[1000*a*V2-K1(V1+V2)] / V1K>m;

[0161] C=[1000*a*(V2+V4)-K2(V1+V2+V4)] / V1n<K<m;

[0162] C=[1000*a*(V2+V5)-K3(V1+V2+V5)] / V1K<n;

[0163] Where, C is the chlorine requirement of raw water, in mg / l, a is the concentration of sodium hypochlorite, in mg / ml,

[0164] V2 is the initial amount of sodium hypochlorite added, in ml.

[0165] V4 is the secondary addition amount of sodium hypochlorite when n<K<m, unit is ml;

[0166] V5 is the secondary addition amount of sodium hypochlorite when K < n, in ml.

[0167] K is the residual chlorine in the solution during pre-test, in mg / l;

[0168] K1 is the residual chlorine value of the solution in the test tank when K≥m, in mg / l;

[0169] K2 is the residual chlorine value of the test tank solution when n<K<m, in mg / l;

[0170] K3 is the residual chlorine value of the solution in the detection tank when K < n, in mg / l;

[0171] m, n are constants, and m>n>0.

[0172] The time for the second injection of the secondary reaction tank is set by the following method;

[0173] When K>m, after (T0+T1) / Nmin, the next-level reaction tank is sampled, the water inlet peristaltic pump and the switching valve are started to feed V1ml of raw water into the reaction tank, and the micro-injection pump and the switching valve are started to add sodium hypochlorite with a concentration of amg / ml and a volume of V2ml into the reaction tank;

[0174] When n<K<m, after (T0+T2) / Nmin, the next-level reaction tank is sampled, the water inlet peristaltic pump and the switching valve are started to feed V1ml of raw water into the reaction tank, and the micro-injection pump and the switching valve are started to add sodium hypochlorite with a concentration of amg / ml and a volume of V2ml into the reaction tank;

[0175] When K<n, after (T0+T3) / Nmin, the next-level reaction tank is sampled, the water inlet peristaltic pump and the switching valve are started to feed V1ml of raw water into the reaction tank, and the micro-injection pump and the switching valve are started to add sodium hypochlorite with a concentration of amg / ml and a volume of V2ml into the reaction tank.

[0176] In this way, through multiple reaction tanks, each reaction tank is sampled according to a preset time interval, which can increase the detection frequency exponentially and detect water quality changes in a timely manner.

[0177] Example 4

[0178] This embodiment provides a specific automatic detection step as follows:

[0179] Step 1: Set the sodium hypochlorite concentration a and the initial dosage V2 on the control and display unit.

[0180] Step 2: Change the control mode to automatic control on the control and display unit.

[0181] Step 3: Start the water inlet peristaltic pump to add liquid to the reaction tank, and time T1 minute.

[0182] Step 4: Turn on the mixer and stir.

[0183] Step 5: Turn on the micro-injection pump and add sodium hypochlorite. When the set amount is reached, turn off the micro-injection pump.

[0184] Step 6: The liquid level sensor detects the liquid level signal, the reaction tank reaches the set liquid inlet volume V1, and the water inlet peristaltic pump is turned off.

[0185] Step 7: Time T2 minutes and stop the mixing agitator.

[0186] Step 8: Set the timer to T3 minutes, open the pre-test tank liquid inlet valve and the residual chlorine test switch valve, and the residual chlorine test unit will perform residual chlorine test.

[0187] Step 9: The liquid level signal of the liquid level sensor disappears and reaches the set volume V3, and the pre-detection tank inlet valve is closed.

[0188] Step 10: Time to T4 minutes and close the residual chlorine detection switching valve.

[0189] Step 11: If the residual chlorine detection unit detects a value n<K<m, the micro-injection pump is turned on to add sodium hypochlorite until the set amount V4 is reached, the micro-injection pump is turned off, the timing T7 is up, and the process proceeds to step 14;

[0190] Step 12: If the residual chlorine detection unit detection value K < n, turn on the micro-injection pump, add sodium hypochlorite, reach the set amount V5, turn off the micro-injection pump, time T7 to go to step 14;

[0191] Step 13: If the residual chlorine detection unit detects the value K ≥ m, the timing T4 is up, and the process goes to step 14; Step 14: Open the liquid inlet valve of the detection tank, the residual chlorine detection unit performs residual chlorine detection, and the control and display unit calculates and displays the raw water chlorine demand in real time.

[0192] C=[1000*a*V2-K1(V1+V2)] / V1K>m;

[0193] C=[1000*a*(V2+V4)-K2(V1+V2+V4)] / V1n<K<m;

[0194] C=[1000*a*(V2+V5)-K3(V1+V2+V5)] / V1K<n;

[0195] Where, C is the chlorine demand of raw water, in mg / l, a is the concentration of sodium hypochlorite, in mg / ml;

[0196] V1 is the original water volume, in ml;

[0197] V2 is the initial amount of sodium hypochlorite added, in ml;

[0198] V4 is the secondary addition amount of sodium hypochlorite when n<K<m, unit is ml;

[0199] V5 is the secondary addition amount of sodium hypochlorite when K < n, in ml;

[0200] K is the residual chlorine in the solution during pre-test, in mg / l;

[0201] K1 is the residual chlorine value of the solution in the test tank when K≥m, in mg / l;

[0202] K2 is the residual chlorine value of the test tank solution when n<K<m, in mg / l;

[0203] K3 is the residual chlorine value of the solution in the detection tank when K < n, in mg / l;

[0204] m, n are constants, and m>n.

[0205] Step 15: Time T5 seconds, close the liquid inlet valve of the detection tank, and open the drain valve of the reaction tank.

[0206] Step 16: Time T6 seconds, close the reactor drain valve, and then proceed to step 1.

[0207] 3. The one-key calibration function of the reagent concentration of the automatic chlorine demand detection device is as follows:

[0208] Step 1: Set the initial dosage V2 on the control and display unit and switch the control mode to manual control; Step 2: Click the drug concentration calibration button on the control and display unit.

[0209] Step 3: The device automatically opens the liquid inlet switching valve, starts the water inlet peristaltic pump, and feeds pure water into the reaction tank, with a timing of T1 minute.

[0210] Step 4: Turn on the mixer and mix.

[0211] Step 5: Turn on the micro-injection pump and add sodium hypochlorite. When the set amount is reached, turn off the micro-injection pump.

[0212] Step 6: The liquid level sensor detects the liquid level signal, the reaction tank reaches the set liquid inlet volume V1, and the water inlet peristaltic pump is turned off to stop the pure water inlet.

[0213] Step 7: Time T2 minutes and stop the mixing agitator.

[0214] Step 8: Set the timer to T3 minutes, open the pre-test tank liquid inlet valve and the residual chlorine test switch valve, and the residual chlorine test unit will perform residual chlorine test.

[0215] Step 9: When the liquid level signal of the liquid level sensor disappears, close the liquid inlet valve of the pre-detection tank.

[0216] Step 10: Time to T4 minutes and close the residual chlorine detection switching valve.

[0217] Step 11: Automatically calculate the concentration of the reagent: the residual chlorine detection unit detection value K1,

[0218] a1=(V1+V2)*K1 / (1000*V2);

[0219] Among them, a1 is the actual sodium hypochlorite, unit mg / ml

[0220] V1 is the volume of pure water, in ml;

[0221] V2 is the amount of sodium hypochlorite added, in ml;

[0222] K1 is the residual chlorine value of the pre-test tank solution, in mg / l;

[0223] Automatically display a1 on the control and display unit display.

[0224] Step 12: Open the drain valve of the reaction tank and the vent valve of the pre-test tank.

[0225] Step 14: Time T5 seconds, close the reaction tank drain valve and the pre-test tank vent valve, and complete the reagent concentration calibration.

[0226] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A chlorine demand automatic detection system, characterized in that: At least includes but is not limited to a sampling module, a reaction module, a detection module and a control and display module; the reaction module is connected to the sampling module, at least one reaction tank is provided in the reaction module, the detection module is connected to the reaction module, and the control and display module is respectively connected to the sampling module, the reaction module and the detection module.

2. The automatic chlorine demand detection system according to claim 1, characterized in that: The injection module includes a liquid inlet switching valve, a liquid inlet pump and a reagent dosing component; one end of the liquid inlet switching valve is connected to the pure water inlet pipe and the raw water inlet pipe respectively, and the other end is connected to the liquid inlet pump, and the liquid inlet pump and the reagent dosing component are connected to the reaction module.

3. An automatic chlorine demand detection system as claimed in claim 1 or 2, characterized in that: The reaction module includes a reaction tank, a pre-test tank and a detection tank, wherein the reaction tank is connected to the pre-test tank and the detection tank through a first pipeline and a second pipeline respectively; the liquid inlet end of the reaction tank is connected to a medicine giving component and a liquid inlet pump respectively, and the pre-test tank and the detection tank are connected to the detection module through pipelines.

4. The automatic chlorine demand detection system according to claim 3, characterized in that: The detection module includes a detection switching valve, a filter assembly and a residual chlorine detection unit; the detection switching valve is connected to the pre-test tank and the detection tank respectively, the detection switching valve is connected to the filter assembly, and the filter assembly is connected to the residual chlorine detection unit; a stirring assembly is arranged at the top position of the reaction tank, at least two liquid level sensors are arranged on the inner wall of the reaction tank, a pre-test liquid inlet valve is arranged on the first pipeline, and a detection liquid inlet valve is arranged on the second pipeline; a drain valve is also arranged at the bottom of the reaction tank, and a pre-test vent valve and a detection vent valve are also arranged at the bottom of the pre-test tank and the detection tank; the control and display module includes a controller and a touch screen; the controller is electrically connected to the components in the injection module, the reaction module and the detection module, and the touch screen is connected to the controller.

5. A method for automatically detecting chlorine demand, characterized in that: It includes the following steps: S1: Take samples, start the liquid inlet pump to feed raw water into the reaction tank, and start the reagent setting component to add reagents into the reaction tank; S2: Reaction: After a short-time chlorination reaction, the chlorine consumption of the water body is pre-judged. If the residual chlorine is sufficient, it will automatically enter the detection tank for residual chlorine detection after sufficient reaction; if the residual chlorine is insufficient, it will automatically add the drug for the second time, and then enter the detection tank for residual chlorine detection after sufficient reaction; S3: Detection: Detect the free residual chlorine index through the residual chlorine detection unit; S4: Calculation. Through analysis and comparison, the calculation module is capable of automatically identifying and eliminating abnormal data, automatically selecting normal data within the measurement cycle and displaying it on the human-computer interaction interface; and repeating S1 to S4 as needed.

6. A method for automatically detecting chlorine demand as claimed in claim 5, characterized in that: In S1, the specific steps of sampling are: start the water inlet peristaltic pump to feed V1ml of raw water into the reaction tank, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V2ml into the reaction tank; In S2, the specific steps of the reaction are: start the stirring component to fully mix the solution in the reaction tank; after T0 minutes, put V3ml of the mixed solution into the pre-test tank and detect the residual chlorine value Kmg / l of the mixed solution; judge the K value; When K>m, after T1min, open the test liquid inlet valve and put the solution into the test tank; When n<K<m, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V4ml into the reaction tank, and after T2min, open the detection liquid inlet valve to put the solution into the detection tank; When K<n, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V5ml into the reaction tank. After T3min, open the detection liquid inlet valve to put the solution into the detection tank.

7. A method for automatically detecting chlorine demand as claimed in claim 5, characterized in that: In S3, the specific steps of detection are: detecting the free residual chlorine index through a residual chlorine detection unit; When K>m, after T1min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K1mg / l; When n<K<m, after T2min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K2mg / l; When K<n, after T3min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K3mg / l, T1<T2<T3; in S4, the specific steps of calculation are to obtain the expression of raw water chlorine demand according to steps S1, S2, and S3: C=[1000*a*V2-K1(V1+V2)] / V1K>m C=[1000*a*(V2+V4)-K2(V1+V2+V4)] / V1n<K<m C=[1000*a*(V2+V5)-K3(V1+V2+V5)] / V1K<n Wherein, C is the chlorine demand of raw water, in mg / l; a is the concentration of sodium hypochlorite, in mg / l; V2 is the initial dosage of sodium hypochlorite, in ml; V4 is the secondary dosage of sodium hypochlorite when n<K<m, in ml; V5 is the secondary dosage of sodium hypochlorite when K<n, in ml; K is the residual chlorine of the solution during pre-test, in mg / l; K1 is the residual chlorine value of the solution in the test tank when K≥m, in mg / l; K2 is the residual chlorine value of the solution in the test tank when n<K<m, in mg / l; K3 is the residual chlorine value of the solution in the test tank when K<n, in mg / l; m and n are constants, and m>n>0.

8. A method for automatically detecting chlorine demand as claimed in claim 5, characterized in that: In S4, a drug concentration calibration process is also provided, which includes the following steps: S41: Take a sample, open the liquid inlet switching valve, start the water inlet peristaltic pump to feed V1ml of pure water into the reaction tank, start the micro-injection pump to add sodium hypochlorite with a concentration of a mg / ml and a volume of V2ml into the reaction tank; S42: Reaction, start the mixing and stirring component to fully mix the solution in the reaction tank; after T1 minute, put V3ml of the mixed solution into the pre-inspection tank; S43: Detection, through the residual chlorine detection unit, after T1min, the residual chlorine detection unit measures the residual chlorine value of the solution to be K1mg / l; S44: Data calculation, according to steps S41, S42, S43, the sodium hypochlorite concentration expression is obtained: a1=(V1+V2)*K1 / (1000*V2) Among them, a1 is the actual sodium hypochlorite, in mg / ml; V1 is the volume of pure water, in ml; V2 is the amount of sodium hypochlorite added, in ml; K1 is the residual chlorine value of the solution in the pre-test tank, in mg / l.

9. A method for automatically detecting chlorine demand, characterized in that: The method includes N reaction tanks, the input ends of the N reaction tanks are connected to the sample injection module, and the output ends of the N reaction tanks are respectively connected to the pre-test tank and the reaction tank; It includes the following steps: S1: Take samples in sequence, start the liquid inlet pump to feed raw water into the designated reaction tank, and start the reagent setting component to add sodium hypochlorite into the designated reaction tank; S2: Reaction: After a short-time chlorination reaction, the chlorine consumption of the water body is pre-judged. If the residual chlorine is sufficient, it will automatically enter the detection tank for residual chlorine detection after sufficient reaction; if the residual chlorine is insufficient, it will automatically add the drug for the second time, and then enter the detection tank for residual chlorine detection after sufficient reaction; S3: Detection: Detect the free residual chlorine index through the residual chlorine detection unit; after setting the interval time according to the number of reaction tanks N and the water pollution situation, start the sampling operation of the next-level reaction tank, where N is an integer greater than 1; S4: Calculation. Through analysis and comparison, the calculation module is capable of automatically identifying and eliminating abnormal data, automatically selecting normal data within the measurement cycle and displaying it on the human-computer interaction interface; and repeating S1 to S4 as needed.

10. A method for automatically detecting chlorine demand as claimed in claim 9, characterized in that: In S3, the specific steps of detection are: detecting the free residual chlorine index through a residual chlorine detection unit; When K>m, after T1min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K1mg / l; When n<K<m, after T2min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K2mg / l; When K<n, after T3min, the residual chlorine value of the solution measured by the residual chlorine detection unit is K3mg / l; The time for the second injection of the secondary reaction tank is set by the following method; When K>m, after (T0+T1) / Nmin, the next-level reaction tank is sampled, the water inlet peristaltic pump and the switching valve are started to feed V1ml of raw water into the reaction tank, and the micro-injection pump and the switching valve are started to add sodium hypochlorite with a concentration of amg / ml and a volume of V2ml into the reaction tank; When n<K<m, after (T0+T2) / Nmin, the next-level reaction tank is sampled, the water inlet peristaltic pump and the switching valve are started to feed V1ml of raw water into the reaction tank, and the micro-injection pump and the switching valve are started to add sodium hypochlorite with a concentration of amg / ml and a volume of V2ml into the reaction tank; When K<n, after (T0+T3) / Nmin, the next-level reaction tank is sampled, the water inlet peristaltic pump and the switching valve are started to feed V1ml of raw water into the reaction tank, and the micro-injection pump and the switching valve are started to add sodium hypochlorite with a concentration of amg / ml and a volume of V2ml into the reaction tank.

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