Dual-chamber split-flow stepwise mechanical pipeline mixer and control method thereof

Abstract

This invention discloses a dual-chamber, split-flow, step-by-step mechanical pipeline mixer and its control method. The mixer includes an upper mixing chamber and a lower mixing chamber separated by a water seal baffle. An axial thrust guide shroud is fixed on the water seal baffle. The outlet of the lower mixing chamber is connected to an outlet pipe. The upper mixing chamber is connected to an inlet pipe via a split pipe. A stirring device extending into the axial thrust guide shroud is installed on the upper mixing chamber. A first dosing device and a second dosing device are respectively installed at the split pipe and the axial thrust guide shroud. The lower mixing chamber is connected to the inlet pipe via a venturi tube. The cross-sectional area of ​​the venturi tube neck is 20-30% of the cross-sectional area of ​​the inlet pipe, and the cross-sectional area of ​​the venturi tube neck plus the cross-sectional area of ​​the split pipe is greater than or equal to the cross-sectional area of ​​the inlet pipe. The stirring device, the first dosing device, and the second dosing device are all electrically connected to the controller.

Description

Technical Field

[0001] This invention relates to the field of water treatment, specifically to a dual-chamber split-flow step-by-step mechanical pipeline mixer and its control method. Background Technology

[0002] Coagulation refers to the process of agglomerating colloidal particles and tiny suspended solids in water through a certain method (such as adding chemical agents). It is a unit operation in water and wastewater treatment processes. Mixing and reaction are two stages in the coagulation process. The role of mixing is to rapidly and uniformly diffuse the agent into the water to create favorable conditions for hydrolysis and polymerization. The role of reaction is to enable the agglomerated particles to form large flocs with good sedimentation properties through flocculation.

[0003] The existing technology ZL202110587402.6 discloses a dual-chamber three-dimensional high-power mechanical pipeline mixer, which can fully mix the added agents through a stirrer and multiple mixing plates inside the pipeline. However, during water purification, when the water supply to the inlet pipeline decreases, the inlet flow rate cannot meet the flow requirements of the diversion pipe. The flow-guiding mixing plates installed in the main inlet pipeline cannot limit the flow or perform the function of guiding and mixing. Furthermore, experiments have shown that designing the diversion pipe to be 15%~20% the diameter of the main inlet pipeline results in a smaller inlet flow rate in the upper mixing chamber, leading to a larger ratio of the discharge volume in the upper mixing chamber to the flow rate in the lower mixing chamber, thus affecting the mixing effect. Summary of the Invention

[0004] In view of the above-mentioned shortcomings in the prior art, the dual-chamber split-flow step-by-step mechanical pipeline mixer and its control method provided by the present invention solve the problem of poor mixing effect of existing pipeline mixers when the inlet water flow is reduced.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0006] A dual-chamber, split-flow, step-by-step mechanical pipeline mixer is provided, comprising an upper mixing chamber and a lower mixing chamber separated by a water seal baffle, wherein an axial thrust guide shroud is fixed on the water seal baffle; the outlet of the lower mixing chamber is connected to an outlet pipe; the upper mixing chamber is connected to an inlet pipe via a split pipe, and a stirring device extending into the axial thrust guide shroud is installed on the upper mixing chamber; a first dosing device and a second dosing device are respectively provided at the split pipe and the axial thrust guide shroud;

[0007] The lower mixing chamber is connected to the inlet pipe via a Venturi tube. The cross-sectional area of ​​the venturi tube neck is 20-30% of the cross-sectional area of ​​the inlet pipe. The cross-sectional area of ​​the venturi tube neck plus the cross-sectional area of ​​the diversion pipe is greater than or equal to the cross-sectional area of ​​the inlet pipe. The stirring device, the first dosing device, and the second dosing device are all electrically connected to the controller.

[0008] The beneficial effects of this invention are as follows: After setting up a Venturi pipe between the water inlet pipe and the lower mixing chamber, the flow rate of the water inlet pipe can be limited when the water supply is reduced, so as to avoid the flow rate in the diversion pipe being greatly reduced and affecting the mixing effect of water and reagent; furthermore, the jet mixing effect generated by the Venturi pipe is far better than the mixing effect of the flow guiding mixing plate.

[0009] The unique configuration of the Venturi tube and the cross-sectional area of ​​the diversion pipe in this design can increase the cross-sectional area of ​​the diversion pipe, allowing the upper mixing chamber to fully utilize its mixing efficiency, and reducing the ratio of liquid discharge to liquid inlet flow in the upper and lower mixing chambers, thereby improving the mixing effect.

[0010] Furthermore, the stirring device includes a power unit installed on the top of the upper mixing chamber. The power unit is connected to a drive shaft. The drive shaft is equipped with a stirring impeller located in the middle part of the upper mixing chamber and a thrust stirring impeller located inside the axial thrust guide shroud. The bottom surface of the thrust stirring impeller is higher than the top surface of the liquid inlet pipe.

[0011] The beneficial effects of the above technical solution are as follows: the process of the impeller of this solution discharging the mixture downward in a spiral shape can remix the mixture. The mixture that reaches the axial thrust guide shroud is discharged downward in a spiral shape again by the thrust impeller. The spiral discharge has axial flow and circumferential circulation, which makes the mixture and the radial flow entering from the main inlet pipe form a three-dimensional fluid flow in the lower mixing chamber, realizing strong hydraulic shear or high turbulence, making the liquid achieve multiple turbulence, making the mixing more uniform, and greatly improving the mixing effect.

[0012] Furthermore, an arc-shaped plate is hinged to the upper surface of the axial thrust deflector, and the total area of ​​the arc-shaped plate is less than half of the flow area of ​​the axial thrust deflector; a connecting block is fixedly installed on the top edge of the arc-shaped plate, and the top edge of the connecting block adjacent to the edge of the axial thrust deflector is hinged to the push rod end of the electric push rod, and the other end of the electric push rod is hinged to the side wall of the upper mixing chamber, and the electric push rod is electrically connected to the controller.

[0013] The beneficial effects of the above technical solution are as follows: After the arc plate is set in this solution, the outlet flow rate of the upper mixing chamber can be adjusted when the inlet flow rate decreases, so as to ensure that the mixed liquid entering the upper mixing chamber has sufficient residence time and ensures mixing efficiency.

[0014] Furthermore, water seal baffles extend from both ends of the axial thrust guide shroud, and the outlet of the second dosing device is located directly above the axial thrust agitator impeller.

[0015] Furthermore, a hollow sphere with a diameter equal to that of the branch pipe is installed inside the branch pipe at the first dosing device; the hollow sphere is provided with a main water inlet and several evenly distributed water passage holes, with the main water inlet located at the water surface of the branch pipe;

[0016] The main water inlet is connected to the rotating nozzle. The rotating nozzle includes a water inlet pipe that is fixedly connected to the main water inlet. A spherical shell is rotatably mounted on the free end of the water inlet pipe via a bearing. Several water outlet holes are evenly distributed on the spherical shell.

[0017] The first dosing device has an L-shaped outlet pipe located in the diversion pipe, and its outlet extends into the main water inlet of the hollow sphere.

[0018] The beneficial effects of the above technical solution are as follows: The liquid entering the diversion pipe and the chemical solution added by the first dosing device enter the hollow sphere simultaneously. They are initially mixed under the rotating spherical shell, and then sprayed through the spherical shell to different positions of the hollow sphere to mix again with the liquid inside the hollow sphere. The mixture flows out from the water passage hole, disturbing the water in the diversion pipe, so that the mixed liquid flowing out of the hollow sphere is fully mixed, thereby ensuring that the chemical in the liquid diffuses rapidly and evenly, and improving the purification effect of the water.

[0019] Furthermore, the dual-chamber diversion and step-by-step mechanical pipeline mixer also includes a third dosing device installed on the liquid outlet pipe and a mixing device located inside the liquid outlet pipe. The third dosing device is electrically connected to the controller. The mixing device includes a first water-passing plate and a second water-passing plate installed inside the liquid outlet pipe and having a diameter equal to that of the liquid outlet pipe. At least half of the upper surface of the first water-passing plate is evenly distributed with a plurality of water-passing holes.

[0020] The second water-passing plate has several water-passing holes evenly distributed; multiple guide plates are evenly spaced and staggered on the liquid outlet pipe between the first and second water-passing plates, and the guide plate adjacent to the first water-passing plate is installed on the upper half of the liquid outlet pipe section; the guide plate has several water-passing holes evenly distributed, and the height of the guide plate is between the radius and diameter of the liquid outlet pipe; the outlet of the third dosing device is located between the first water-passing plate and the guide plate adjacent to the first water-passing plate.

[0021] The beneficial effects of the above technical solution are as follows: the mixing device allows the mixed liquid to be mixed multiple times with the agent added by the third dosing device, so as to ensure that the agent in the liquid is rapidly and evenly diffused in the water, thereby creating good hydrolysis and polymerization conditions and improving the purification effect of the water.

[0022] Furthermore, the axial height of the lower mixing chamber is 300-400 mm larger than the diameter of the inlet and / or outlet pipes.

[0023] The beneficial effects of the above technical solution are as follows: The radial section design of the lower mixing chamber of ZL202110587402.6 cannot meet the mixing time requirement of the lower mixing chamber with a mixing residence time of ≥4s at a flow velocity of 0.8m / s. After introducing the Venturi tube in this solution, combined with the unique setting of the axial height of the lower mixing chamber, it can ensure that the mixing time of the lower mixing chamber is ≥ the optimal coagulant mixing requirement on the basis of 120% of the water plant's designed production capacity.

[0024] Secondly, a control method for a dual-chamber split-flow step-by-step mechanical pipeline mixer is provided, characterized by comprising the following steps:

[0025] S1. When there is flow in the upper mixing chamber, start the stirring device, the first dosing device and the second dosing device;

[0026] S2. Collect the cross-sectional flow rate of the diversion pipe every preset time interval, and determine whether the cross-sectional flow rate is less than the cross-sectional flow rate of the axial thrust guide. If it is, proceed to step S3; otherwise, proceed to step S6.

[0027] S3. Control the electric push rod to extend, drive the arc plate to a horizontal state, and determine whether the cross-sectional flow rate of the diversion pipe is less than the preset flow rate. If yes, proceed to step S4; otherwise, proceed to step S6.

[0028] S4. Calculate the output power of the stirring motor based on the cross-sectional flow rate of the diversion pipe:

[0029]

[0030] in, N This refers to the output power of the stirring motor; μ The viscosity of water; t For designing mixed time; Q The flow rate of the upper mixing chamber; η For the conversion efficiency of the stirring motor; G For velocity gradient; q 1 and q 2 represents the cross-sectional flow rate collected in two consecutive measurements of the diversion pipeline;

[0031] S5. Adjust the output power of the stirring motor of the power unit, and adjust the output of the first and second dosers to the level of the previous moment. times, Q 1 and Q 2 represents the cross-sectional flow rate collected from two adjacent samples of the inlet pipe, and then proceeds to step S7;

[0032] S6. Keep the curved plate vertical and adjust the dosage of the first and second dosing devices to the level of the previous moment. Then proceed to step S7;

[0033] S7. Determine if there is flow in the upper mixing chamber. If yes, return to step S2. Otherwise, turn off the stirring device, the first dosing device and the second dosing device, and keep the arc plate in a vertical position.

[0034] Furthermore, when water is flowing out of the outlet pipe, it also includes determining whether the water flow from the outlet pipe meets the water plant's design requirements. If it does not meet the requirements, the third dosing device is activated; otherwise, the third dosing device is not activated.

[0035] The beneficial effects of the above technical solution are as follows: In the process of water purification, this solution can judge the flow rate entering the diversion pipe to adjust the arc plate, so as to ensure the residence time of the mixed liquid in the upper mixing chamber and thus ensure the uniformity of mixing; by inputting the flow rate change of the diversion pipe, the output power of the stirring motor can be adjusted to ensure thorough mixing while saving energy.

[0036] Thirdly, a control method for a dual-chamber split-flow step-by-step mechanical pipeline mixer is provided, characterized by comprising the following steps:

[0037] S1, Gt optimized closed-loop hybrid control

[0038] S11. Collect the pH value of the raw water and the flow current SC of the raw water using a flow current detector as reference values. Set the mixing time t to 4~10s according to the flow rate change. Set the speed of the stirring motor to 200 rpm. The coagulant dosage is set based on the coagulant dosage in the beaker experiment for 1,000 tons of water.

[0039] S12. According to the parameters set in step S11, the mixer enters the manual operation experimental state. The current detector is used to detect SC and the corresponding mixer stirring motor speed. The stirring motor speed is increased, and the change value of SC is recorded as the increase is increased. When the detected SC value approaches and stabilizes at a value greater than or less than the SC reference value, the detected SC value is used as the automatic operation setting value.

[0040] S13. Automatic control operation: The mixer enters the automatic operation mixing and adjustment state. After entering automatic operation, the controller uses the SC reference value as the target, automatically adjusts the speed of the stirring motor, and observes the relative difference between the SC value and the SC set value. If it is ≥ the SC set value, the colloid polymerization sedimentation effect conforms to the relationship between the raw water pH value and the coagulant.

[0041] S2, PID variable frequency dosing system closed-loop control

[0042] S21. Take the observed SC≥SC set value, and use the coagulant dosage based on the Gt optimized closed-loop mixing control dosage.

[0043] S22 and Gt optimized closed-loop hybrid control are running normally and automatically. Manually adjust the variable frequency dosing system and detect the effect of increasing or decreasing the dosage on the SC detection value.

[0044] S23. Based on the mixing effect SC value generated under the Gt optimized closed-loop mixing control, the coagulant dosage of the PID variable frequency dosing system is automatically adjusted. If the SC value approaches SC≤zero during the adjustment process, the coagulant dosage is adjusted and the PID variable frequency control system continues to adjust automatically; otherwise, the PID variable frequency control system automatically stops adjusting the coagulant dosage. Attached Figure Description

[0045] Figure 1 Front view of a dual-chamber split-flow mechanical pipeline mixer;

[0046] Figure 2 A top view of a dual-chamber split-flow mechanical pipeline mixer;

[0047] Figure 3 for Figure 1 Enlarged view of section A in the middle;

[0048] Figure 4 A schematic diagram of a hollow sphere with a rotating nozzle installed inside;

[0049] Figure 5 A schematic diagram of a mixing device installed inside the liquid outlet pipe;

[0050] Figure 6 This is a schematic diagram illustrating the flow principle of the liquid medium inside a dual-chamber split-flow step-by-step mechanical pipeline mixer.

[0051] The components are as follows: 1. Upper mixing chamber; 11. Upper guide plate; 2. Lower mixing chamber; 21. Lower guide plate; 22. Venturi tube; 3. Water seal baffle; 4. Axial thrust guide shroud; 41. Arc plate; 42. Connecting block; 43. Electric push rod; 5. Stirring device; 51. Stirring impeller; 52. Stirring motor; 53. Drive shaft; 54. Thrust stirring impeller; 6. Inlet pipe; 7. Outlet pipe; 71. Mixing device; 711. First water-passing plate; 712. Second water-passing plate; 713. Guide plate; 8. Diversion pipe; 81. Hollow sphere; 811. Water-passing hole; 82. Rotary nozzle; 821. Inlet pipe; 822. Bearing; 823. Spherical shell; 83. Second dosing device; 84. Mixing guide plate; 9. First dosing device; 10. Third dosing device. Detailed Implementation

[0052] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0053] like Figure 1 and Figure 2 As shown, the dual-chamber split-flow mechanical pipeline mixer provided in this solution includes an upper mixing chamber 1 and a lower mixing chamber 2 separated by a water seal baffle 3. An axial thrust guide hood 4 is fixed on the water seal baffle 3. The outlet of the lower mixing chamber 2 is connected to the liquid outlet pipe 7. The upper mixing chamber 1 is connected to the liquid inlet pipe 6 through a split pipe 8. A stirring device 5 extending into the axial thrust guide hood 4 is installed on the upper mixing chamber 1. A first dosing device 9 and a second dosing device 83 are respectively provided at the split pipe 8 and the axial thrust guide hood 4.

[0054] The lower mixing chamber 2 is connected to the inlet pipe 6 via a venturi tube 22. The cross-sectional area of ​​the neck of the venturi tube 22 is 20-30% of the cross-sectional area of ​​the inlet pipe 6. The cross-sectional area of ​​the neck of the venturi tube 22 plus the cross-sectional area of ​​the diversion pipe is greater than or equal to the cross-sectional area of ​​the inlet pipe 6. The stirring device 5, the first dosing device 9, and the second dosing device 83 are all electrically connected to the controller.

[0055] like Figure 6 As shown in the attached diagram, the working principle of the dual-chamber split-flow step-by-step mechanical pipeline mixer of this scheme will be explained in detail below:

[0056] During equipment operation, the water flow X from the inlet pipe 6 enters the upper mixing chamber 1 through the branch pipe 8. The coagulant is added to the branch pipe 8 via the first dosing device 9. A small volume of the branch flow X mixes with the coagulant through primary turbulent mixing to form a small volume of primary liquid, which is then introduced into the upper mixing chamber 1. Within the upper mixing chamber 1, the stirring impeller 51 provides powerful mechanical mixing, creating secondary turbulent mixing to achieve a more uniform mixing effect for the primary mixture. This achieves a small-sized, powerfully stirred second mixing zone and a secondary mixture. The secondary mixture is connected to the sealed upper mixing chamber 1 and lower mixing chamber 2 only through an axial thrust guide shroud 4. The high-speed rotation of the thrust stirring impeller 54 within the axial thrust guide shroud 4 generates high turbulence in the upper liquid, causing the liquid within the upper mixing chamber 1 to flow through the branch pipe 8... The introduced primary mixed liquid and the drug solution added through the second dosing device 83 generate strong shear, making the secondary mixture more uniform. The high-speed rotation of the stirring device 5 forces the secondary mixture downward in an axial spiral shape through the axial guide shroud and axial thrust impeller. The spiral discharge has axial flow and circumferential circulation. This discharged liquid first passes through the inlet pipe 6 radially and collides with the bottom of the lower mixing chamber 2 to form a reverse axial flow and circumferential circulation. Secondly, the forward and reverse axial flow and circumferential circulation generate multiple hydraulic shears with the radial flow of the Venturi tube jet, and form a three-dimensional liquid flow in the lower mixing chamber 2. Finally, a tertiary mixture is achieved in a closed environment where the main fluid and the secondary mixture undergo rapid hydraulic shear and highly turbulent mixing at all times and at all flow rates, which greatly improves the mixing effect.

[0057] Refer again Figure 1The stirring device 5 includes a power unit installed on the top of the upper mixing chamber 1. The power unit includes a stirring motor 52 and a reducer connected to the stirring motor 52. The output end of the reducer is connected to the drive shaft 53. The drive shaft is equipped with a stirring impeller 51 located in the middle part of the upper mixing chamber 1 and a thrust stirring impeller 54 located inside the axial thrust guide shroud 4. The bottom surface of the thrust stirring impeller 54 is higher than the top surface of the liquid inlet pipe 6.

[0058] like Figure 3 As shown, an arc-shaped plate 41 is hinged to the upper surface of the axial thrust guide shroud 4. The total area of ​​the arc-shaped plate 41 is less than half of the flow area of ​​the axial thrust guide shroud 4. A connecting block 42 is fixedly installed on the top edge of the arc-shaped plate 41. The top edge of the connecting block 42 adjacent to the edge of the axial thrust guide shroud 4 is hinged to the push rod end of the electric push rod 43. The other end of the electric push rod 43 is hinged to the side wall of the upper mixing chamber 1. The electric push rod 43 is electrically connected to the controller. If the lower surface of the electric push rod 43 in this solution cannot be in contact with the interior of the upper mixing chamber 1, a support block can be fixed on the side wall of the upper mixing chamber 1 to facilitate the support of the electric push rod 43.

[0059] When the flow sensor in the diversion pipe 8 detects a decrease in flow rate inside the diversion pipe 8, and the cross-sectional flow rate is less than the cross-sectional flow rate of the axial thrust guide shroud 4, the controller controls the electric push rod 43 to extend, causing the arc plate 41 to rotate towards the axial thrust guide shroud 4 until it is in a horizontal state. This reduces the outlet area of ​​the axial thrust guide shroud 4, increasing the residence time of the mixed liquid in the upper mixing chamber 1 to achieve uniform mixing. When the cross-sectional flow rate of the diversion pipe increases to a level greater than the cross-sectional flow rate of the axial thrust guide shroud 4, the electric push rod is controlled to shorten until the arc plate 41 is essentially in a vertical state.

[0060] In practice, the preferred design is to extend water seal baffles 3 from both ends of the axial thrust guide shroud 4, and the outlet of the second dosing device 83 is located directly above the axial thrust stirring impeller 54.

[0061] like Figure 4 As shown, a hollow sphere 81 with a diameter equal to that of the diversion pipe 8 is installed inside the diversion pipe 8 at the first dosing device 9; the hollow sphere 81 is provided with a main water inlet and several evenly distributed water passage holes 811, and the main water inlet is located at the water surface of the diversion pipe 8.

[0062] The main water inlet is connected to the rotating nozzle 82. The rotating nozzle 82 includes a water inlet pipe 821 fixedly connected to the main water inlet. A spherical shell 823 is rotatably mounted on the free end of the water inlet pipe 821 via a bearing 822. Several water outlet holes are evenly distributed on the spherical shell 823. The first dosing device 9 has an L-shaped dosing pipe located in the diversion pipe 8, and its outlet extends into the main water inlet of the hollow sphere 81.

[0063] When water flows into the diversion pipe 8, most of the water enters the hollow sphere 81, while some water enters the rotating spherical shell 823 through the main inlet hole, where it undergoes preliminary mixing with the reagent. Then, the water is sprayed through the spherical shell 823 to different positions within the hollow sphere 81, where it mixes again with the liquid inside the hollow sphere 81. The mixture then flows out through the water outlet 811, disturbing the water in the diversion pipe 8. This ensures that the mixture flowing out of the hollow sphere 81 is fully mixed, guaranteeing rapid and uniform diffusion of the reagent in the liquid and improving the water purification effect.

[0064] like Figure 5 As shown, the dual-chamber split-flow mechanical pipeline mixer also includes a third dosing device 10 disposed on the outlet pipeline 7 and a mixing device 71 located inside the outlet pipeline 7. The third dosing device 10 is electrically connected to the controller. The mixing device 71 includes a first water-passing plate 711 and a second water-passing plate 712 disposed inside the outlet pipeline 7 and having a diameter equal to that of the outlet pipeline 7. At least half of the upper part of the first water-passing plate 711 has a plurality of water-passing holes 811 evenly distributed.

[0065] The second water-passing plate 712 has a plurality of water-passing holes 811 evenly distributed on it; the liquid outlet pipe 7 between the first water-passing plate 711 and the second water-passing plate 712 has a plurality of guide plates 713 arranged at equal intervals and in an alternating manner, and the guide plate 713 adjacent to the first water-passing plate 711 is installed on the upper half of the liquid outlet pipe 7; the guide plate 713 has a plurality of water-passing holes 811 evenly distributed on it, and the height of the guide plate 713 is between the radius and the diameter of the liquid outlet pipe 7; the outlet of the third dosing device 10 is located between the first water-passing plate 711 and the guide plate 713 adjacent to the first water-passing plate 711.

[0066] The mixture entering the outlet pipe 7 can undergo primary mixing with the mixture that quickly passes through the first water-passing plate 711. Afterwards, part of the mixture passes through the water-passing hole 811 of the guide plate 713, while the majority of the mixture flows from the gap between the guide plate 713 and the outlet pipe 7 to the next guide plate 713. The water flowing in from the gap will mix again with the water in the water-passing hole 811. This process is repeated so that the mixture is mixed multiple times between the guide plates 713, and finally discharged from the second water-passing plate 712.

[0067] In implementation, the preferred first dosing device 9, second dosing device 83, and third dosing device 10 of this scheme all include a liquid medicine storage device, a liquid medicine output pipe, a liquid medicine flow regulating valve, and a liquid medicine flow sensor. The liquid medicine output pipe is used to deliver the liquid medicine stored in the liquid medicine storage device to the upper mixing area. The liquid medicine flow sensor is used to monitor the flow rate of the liquid medicine in the liquid medicine output pipe and feed it back to the controller. The controller controls the liquid medicine flow regulating valve to adjust the liquid medicine flow rate so that the liquid medicine is always input according to the preset flow rate value.

[0068] In implementation, this scheme preferably allows the axial height of the lower mixing chamber 2 to be 300-400 mm larger than the diameter of the inlet pipe 6 and / or the outlet pipe 7.

[0069] like Figure 1 As shown, a cross-shaped mixing guide plate 84 is provided near the upper mixing chamber 1 in the diversion pipe 8, an upper guide plate 11 is provided in the upper mixing chamber 1, and a lower guide plate 21 is provided in the lower mixing chamber 2.

[0070] This solution also provides a control method for a dual-chamber split-flow stepwise mechanical pipeline mixer, which includes the following steps:

[0071] S1. When there is flow in the upper mixing chamber 1, start the stirring device 5, the first dosing device 9 and the second dosing device 83;

[0072] S2. Collect the cross-sectional flow rate of the diversion pipe 8 every preset time interval, and determine whether the cross-sectional flow rate is less than the cross-sectional flow rate of the axial thrust guide shroud 4. If so, proceed to step S3; otherwise, proceed to step S6.

[0073] S3. Control the electric push rod 43 to extend, drive the arc plate 41 to a horizontal state, and determine whether the cross-sectional flow rate of the diversion pipe 8 is less than the preset flow rate. If it is, proceed to step S4; otherwise, proceed to step S6.

[0074] S4. Calculate the output power of the stirring motor 52 based on the cross-sectional flow rate of the diversion pipe:

[0075]

[0076] in, N This refers to the output power of the stirring motor 52; μ The viscosity of water; t For designing mixed time; Q The flow rate of the upper mixing chamber is 1. η The conversion efficiency of the stirring motor 52; G For velocity gradient; q 1 and q 2 represents the cross-sectional flow rate collected from two adjacent samples of the diversion pipe 8;

[0077] S5. Adjust the output power of the stirring motor 52 of the power unit, and adjust the output of the first dosing device 9 and the second dosing device 83 to the level of the previous moment. times, Q 1 and Q 2 represents the cross-sectional flow rate collected from two adjacent samples of the inlet pipe 6, and then proceeds to step S7;

[0078] S6. Keep the curved plate vertical and adjust the dosage of the first dosing device 9 and the second dosing device 83 to the level of the previous moment. Then proceed to step S7;

[0079] S7. Determine whether there is flow in the upper mixing chamber 1. If yes, return to step S2. Otherwise, turn off the stirring device 5, the first dosing device 9 and the second dosing device 83, and keep the arc plate in a vertical position.

[0080] In practice, this scheme preferably includes determining whether the water flow from the outlet pipe 7 meets the water plant design requirements when there is water flow out of the outlet pipe 7. If it does not meet the requirements, the third dosing device 10 is activated; otherwise, the third dosing device 10 is not activated.

[0081] This solution also provides a control method for a dual-chamber split-flow stepwise mechanical pipeline mixer, characterized by including the following steps:

[0082] S1, Gt optimized closed-loop hybrid control (where G refers to the velocity gradient)

[0083] S11. Collect the pH value of the raw water and the flow current SC of the raw water using a flow current detector as reference values. Set the mixing time t to 4~10s according to the flow rate change. Set the speed of the stirring motor to 200 rpm. The coagulant dosage is set based on the coagulant dosage in the beaker experiment for 1,000 tons of water.

[0084] S12. According to the parameters set in step S11, the mixer enters the manual operation experimental state. The current detector is used to detect SC and the corresponding mixer stirring motor speed. The stirring motor speed is increased, and the change value of SC is recorded as the increase is increased. When the detected SC value approaches and stabilizes at a value greater than or less than the SC reference value, the detected SC value is used as the automatic operation setting value.

[0085] S13. Automatic control operation: The mixer enters the automatic operation mixing and adjustment state. After entering automatic operation, the controller uses the SC reference value as the target, automatically adjusts the speed of the stirring motor, and observes the relative difference between the SC value and the SC set value. If it is ≥ the SC set value, the colloid polymerization sedimentation effect conforms to the relationship between the raw water pH value and the coagulant.

[0086] S2, PID variable frequency dosing system closed-loop control

[0087] S21. Take the observed SC≥SC set value, and use the coagulant dosage based on the Gt optimized closed-loop mixing control dosage.

[0088] S22 and Gt optimized closed-loop hybrid control are running normally and automatically. Manually adjust the variable frequency dosing system and detect the effect of increasing or decreasing the dosage on the SC detection value.

[0089] S23. Based on the mixing effect SC value generated under the Gt optimized closed-loop mixing control, the coagulant dosage of the PID variable frequency dosing system is automatically adjusted. If the SC value approaches SC≤zero during the adjustment process, the coagulant dosage is adjusted and the PID variable frequency control system continues to adjust automatically; otherwise, the PID variable frequency control system automatically stops adjusting the coagulant dosage.

[0090] The two closed-loop systems described above differ in their approaches. The former optimizes Gt (Gross Threat) to create favorable hydraulic conditions for improved mixing. The latter relies on adjusting the coagulant dosage to determine the optimal dosage for enhanced mixing. Both systems share the same goal but employ different methods. The former optimizes the mixing facility's inherent hydraulic conditions using Gt to achieve the best mixing efficiency. The latter, building upon the former's already optimal mixing efficiency, adjusts the coagulant dosage as needed to achieve the best mixing effect. These two systems form a closed-loop control system, sharing the same objective while functioning independently. Their causal relationship is clear, ensuring safety, reliability, and ease of implementation.

[0091] Scheme and working principle of fluid in a three-dimensional turbulent state

[0092] The dual-chamber, split-flow, step-by-step mechanical pipeline mixer adopts a three-dimensional mixing structure design with upper and lower mixing chambers, double-layer mechanical stirring, and hydraulic shearing. A stirring blade and a thrust stirring blade are located at the center of each mixing chamber. Part of the raw water is diverted into the static mixer to complete the initial mixing of the raw liquid and coagulant. It then enters the upper mixing chamber, where mechanical stirring further enhances the strong mixing of the primary mixture. After mixing, it enters the axial thrust guide shroud and, propelled by the high-speed rotation of the thrust stirring blades, enters the lower mixing chamber. There, it forms a three-dimensional hydraulic shearing effect with the radial jet flow from the venturi tube under the influence of the rotating impeller and the flow field, resulting in strong mixing. This allows the coagulant to initially mix with other coagulants. Driven by the impeller, it then enters the lower mixing chamber and is completely mixed with the main stream. When the dual-chamber three-dimensional high-power mechanical pipeline mixer is running, the coagulant is added to the diversion pipe. A primary mixture is formed through static mixing of a small volume of diversion. The primary mixture then enters the upper mixing chamber and is stirred at high speed by a variable frequency speed-regulating agitator, achieving two turbulent flows to form a secondary mixture. The secondary mixture is then discharged into the lower mixing chamber by pressure through an axial flow mechanical agitator. In the lower mixing chamber, hydraulic shearing is achieved with the water inlet in the Venturi tube, and a three-dimensional flow field of radial flow, axial flow, and axial circulation is formed in the lower mixing chamber. This allows the chemical and liquid to achieve rapid, full-flow, and thorough uniform mixing within 4-8 seconds, enabling the coagulant to exert its coagulation effect more fully, reducing emissions and saving energy, with a wide range of applications, and improving the quality of effluent.

[0093] In summary, the pipeline mixer of this solution can achieve uniform mixing of chemicals and water when the water volume is large, and can also ensure the water volume in the diversion pipeline 8 when the water volume is small, so as to avoid a significant reduction in the flow rate in the diversion pipeline 8, which would affect the mixing effect of water and chemicals.

Claims

1. A dual-chamber, multi-stage mechanical pipeline mixer, comprising an upper mixing chamber and a lower mixing chamber separated by a water seal baffle, wherein an axial thrust guide shroud is fixed on the water seal baffle; the outlet of the lower mixing chamber is connected to an outlet pipe; the upper mixing chamber is connected to an inlet pipe via a diversion pipe, and a stirring device extending into the axial thrust guide shroud is installed on the upper mixing chamber; a first dosing device and a second dosing device are respectively provided at the diversion pipe and the axial thrust guide shroud; characterized in that: The lower mixing chamber is connected to the inlet pipe via a Venturi tube. The cross-sectional area of ​​the venturi tube neck is 20-30% of the cross-sectional area of ​​the inlet pipe, and the cross-sectional area of ​​the venturi tube neck plus the cross-sectional area of ​​the diversion pipe is greater than or equal to the cross-sectional area of ​​the inlet pipe. The stirring device, the first dosing device, and the second dosing device are all electrically connected to the controller. The stirring device includes a power unit installed on the top of the upper mixing chamber. The power unit is connected to a drive shaft. The drive shaft is equipped with a stirring impeller located in the middle part of the upper mixing chamber and a thrust stirring impeller located inside the axial thrust guide shroud. The bottom surface of the thrust stirring impeller is higher than the top surface of the liquid inlet pipe. An arc-shaped plate is hinged to the upper surface of the axial thrust guide shield, and the total area of ​​the arc-shaped plate is less than half of the flow area of ​​the axial thrust guide shield. A connecting block is fixedly installed on the top edge of the arc-shaped plate. The top edge of the connecting block, adjacent to the edge of the axial thrust guide, is hinged to the push rod end of the electric push rod. The other end of the electric push rod is hinged to the side wall of the upper mixing chamber. The electric push rod is electrically connected to the controller.

2. The dual-chamber split-flow step-by-step mechanical pipeline mixer according to claim 1, characterized in that, Water seal baffles extend from both ends of the axial thrust guide shroud, and the outlet of the second dosing device is located directly above the axial thrust stirring impeller.

3. The dual-chamber split-flow mechanical pipeline mixer according to claim 1, characterized in that, A hollow sphere with a diameter equal to that of the diversion pipe is installed inside the first dosing device; the hollow sphere is provided with a main water inlet and several evenly distributed water passage holes, and the main water inlet is located at the water inlet surface of the diversion pipe; The main water inlet is connected to the rotating nozzle. The rotating nozzle includes a water inlet pipe fixedly connected to the main water inlet. A spherical shell is rotatably mounted on the free end of the water inlet pipe via a bearing. Several water outlet holes are evenly distributed on the spherical shell. The first dosing device has an L-shaped outlet pipe located in the diversion pipe, and its outlet extends into the main water inlet of the hollow sphere.

4. The dual-chamber split-flow step-by-step mechanical pipeline mixer according to claim 1, characterized in that, It also includes a third dosing device installed on the liquid outlet pipe and a mixing device located inside the liquid outlet pipe. The third dosing device is electrically connected to the controller. The mixing device includes a first water-passing plate and a second water-passing plate installed inside the liquid outlet pipe and having a diameter equal to that of the liquid outlet pipe. At least half of the upper surface of the first water-passing plate is evenly distributed with a plurality of water-passing holes. The second water-passing plate is evenly distributed with several water-passing holes; multiple guide plates are evenly spaced and staggered on the liquid outlet pipe between the first and second water-passing plates, and the guide plate adjacent to the first water-passing plate is installed on the upper half of the liquid outlet pipe section; the guide plate is evenly distributed with several water-passing holes, and the height of the guide plate is between the radius and diameter of the liquid outlet pipe; the outlet of the third dosing device is located between the first water-passing plate and the guide plate adjacent to the first water-passing plate.

5. The dual-chamber split-flow step-by-step mechanical pipeline mixer according to claim 1, characterized in that, The axial height of the lower mixing chamber is 300-400 mm larger than the diameter of the inlet pipe and / or outlet pipe.

6. The dual-chamber split-flow step-by-step mechanical pipeline mixer according to claim 1, characterized in that, The diversion pipe is provided with a cross-shaped mixing guide plate near the upper mixing chamber, the upper mixing chamber is provided with an upper guide plate, and the lower mixing chamber is provided with a lower guide plate.

7. A control method for a dual-chamber split-flow step-by-step mechanical pipeline mixer according to any one of claims 1-6, characterized in that, Including the following steps: S1, Gt optimized closed-loop hybrid control S11. Collect the pH value of the raw water and the flow current SC of the raw water using a flow current detector as reference values. Set the mixing time t to 4~10s according to the flow rate change. Set the speed of the stirring motor to 200 rpm. The coagulant dosage is set based on the coagulant dosage in the beaker experiment for 1,000 tons of water. S12. According to the parameters set in step S11, the mixer enters the manual operation experimental state. The current detector is used to detect SC and the corresponding mixer stirring motor speed. The stirring motor speed is increased, and the change value of SC is recorded as the increase is increased. When the detected SC value approaches and stabilizes at a value greater than or less than the SC reference value, the detected SC value is used as the automatic operation setting value. S13. Automatic control operation: The mixer enters the automatic operation mixing and adjustment state. After entering automatic operation, the controller uses the SC reference value as the target, automatically adjusts the speed of the stirring motor, and observes the relative difference between the SC value and the SC set value. If it is ≥ the SC set value, the colloid polymerization sedimentation effect conforms to the relationship between the raw water pH value and the coagulant. S2, PID variable frequency dosing system closed-loop control S21. Take the observed SC≥SC set value, and use the coagulant dosage based on the Gt optimized closed-loop mixing control dosage. S22 and Gt optimized closed-loop hybrid control are running normally and automatically. Manually adjust the variable frequency dosing system and detect the effect of increasing or decreasing the dosage on the SC detection value. S23. Based on the mixing effect SC value generated under the Gt optimized closed-loop mixing control, the coagulant dosage of the PID variable frequency dosing system is automatically adjusted. If the SC value approaches SC≤zero during the adjustment process, the coagulant dosage is adjusted and the PID variable frequency control system continues to adjust automatically; otherwise, the PID variable frequency control system automatically stops adjusting the coagulant dosage.

8. A control method for a dual-chamber split-flow mechanical pipeline mixer according to any one of claims 1-6, characterized in that, Including the following steps: S1. When there is flow in the upper mixing chamber, start the stirring device, the first dosing device and the second dosing device; S2. Collect the cross-sectional flow rate of the diversion pipe once every preset time interval, and determine whether the cross-sectional flow rate is less than the cross-sectional flow rate of the axial thrust guide. If yes, proceed to step S3; otherwise, proceed to step S6. S3. Control the electric push rod to extend, drive the arc plate to a horizontal state, and determine whether the cross-sectional flow rate of the diversion pipe is less than the preset flow rate. If yes, proceed to step S4; otherwise, proceed to step S6. S4. Calculate the output power of the motor based on the cross-sectional flow rate of the pipe: in, N This refers to the motor's output power. μ The viscosity of water; t For designing mixed time; Q The flow rate of the upper mixing chamber; η For motor conversion efficiency; G For velocity gradient; q 1 and q 2 represents the cross-sectional flow rate collected from two adjacent samples of the diversion pipeline; S5. Adjust the output power of the motor of the power unit, and adjust the output of the first and second dosing devices to the level of the previous moment. times, Q 1 and Q 2 represents the cross-sectional flow rate collected from two adjacent samples of the inlet pipe, and then proceeds to step S7; S6. Keep the electromagnet de-energized and adjust the dosage of the first and second dosing devices to the level of the previous moment. Then proceed to step S7; S7. Determine if there is flow in the upper mixing chamber. If yes, return to step S2. Otherwise, turn off the stirring device, the first dosing device and the second dosing device, and keep the electromagnet in the de-energized state.

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