Nanjing Nanlan Environmental Protection Equipment Manufacturing Co., Ltd. has improved and perfected its existing submersible mixer series products based on the technology of similar foreign products, making its series products close to or reach the level of similar foreign products, and conducting research and development on equipment integration.

Optimization and improvement can be carried out from the following aspects

1. Optimize the hydraulic performance of the submersible mixer impeller

The main function of a submersible mixer is to stir and push the flow. According to the theory of fluid mixing, the main factors affecting the hydraulic performance of the mixer are the shape, size, and placement angle of the impeller. Therefore, the key component of the agitator is the impeller. Optimizing the agitator impeller can improve work efficiency and maximize the flow field generated by the agitator impeller, creating a * flow state. The selection of impeller shape should consider both the lift to drag ratio and improve the cavitation performance of the impeller.

To meet the requirements of different process and mixer flow characteristics, the upward tilt angle oL at the inlet and outlet edges of the impeller can be between 10-30. The adjustment and placement angle can be between 5 and 10. Or around 5-10. Adjusting between them, if the clockwise placement angle is positive, the larger the upward tilt angle d and the larger the placement angle 0, the stronger the cycling ability; Otherwise, the cutting ability will be enhanced and the cycling ability will be weakened. Through mixing experiments, the hydraulic model of a three blade swept back mixer with the same machine number but different specific speeds ns was tested for dynamic characteristics and shear cycle characteristics at different speeds, and optimized for selection. The parameters of mixing characteristics, unit efficiency, and comprehensive economic indicators were finally determined, and then the design parameters for industrial use were calculated through amplification design.

In addition, to generate the largest axial flow, the optimized design of the mixer will adopt a hyperbolic guide cover. Because the flow of people through any mixer impeller is largely axial. In order to help reduce losses and wing tip vortices caused by changes in flow direction, it has been decided to use and develop a diffuser. The diversion hood has appropriate hydraulic design, which can improve the deviation of flow by controlling the flow of people. The pressure difference on the diffuser increases axial flow and reduces radial flow. Therefore, the hydraulic load and vibration on the blades are reduced, and longer and more stable flow is generated. After experiments, the efficiency of the mixer can be increased by 10% to 15% in water, and even more in other fluids with higher viscosity.

When the liquid level is very shallow, it is easy to cause air vortices to enter the agitator impeller thruster from the liquid level, resulting in impeller vibration and performance degradation. To avoid such situations, we have designed a protective cover that can prevent vortex generation and can be reliably connected to the guide cover.

The sealing and protection performance of motors can be solved from the following aspects:

By reasonably selecting the shaft diameter and the inner diameter of the mechanical seal static ring, and appropriately increasing the gap between the shaft and the static ring; By adjusting the axial dimensions, materials, and shaft diameter of the mixer, the rigidity of the shaft can be improved to reduce the deflection of the mixer shaft during operation; By improving the tolerance requirements for the shape and position of the mixer components, as well as the precision of machining and fitting dimensions, the inner ring of the mechanical seal static ring of the main engine will not rub against the shaft within the allowable operating conditions, and the dynamic and static ring surfaces will operate smoothly

Maintain a stable relative parallel state during the rotation process to reduce local wear on the mechanical sealing surface. In theory, the surface of mechanical seals is usually separated by a liquid film. But in reality, there is always direct contact between rings, which leads to wear on the sealing surface. Therefore, the reasonable selection of materials and sliding properties for the friction pair of the dynamic and static rings is very important for the service life of the mechanical seal. The sealing form adopted in this structural design is two sets of independent mechanical seals connected in series. The oil chamber and motor chamber seals use corrosion-resistant sintered tungsten carbide/silicon carbide as the dynamic and static ring materials. The seal between the oil chamber and impeller and the stirring medium is made of corrosion-resistant sintered tungsten carbide. For the bearing box of the mixer with a deceleration mechanism, the shaft sleeve is lengthened to reduce the cantilever length of the mixing shaft, thereby reducing the deflection of the mixing shaft and improving the operating life of the mechanical seal. Improve the machining accuracy and smoothness of the fitting surface of parts, and enhance the mechanical properties and anti-aging properties of static sealing rubber parts.

Developing flexible cables for submersible agitators that exceed typical standards in terms of mechanical performance, particularly in terms of tensile strength, corrosion resistance, and tensile strength. And improve the existing cable sealing structure by adopting a detachable and reusable one-time press vulcanization formed watertight cable to eliminate the sealing hazards of motor incoming cables.

To enhance the reliability of the motor and ensure its service life, the insulation level of the motor is F and the protection level is IP68. Water leakage and winding overheating protection are installed inside the motor chamber. The stator winding of the motor adopts the vacuum pressure impregnation solvent-free paint (VPI) process technology, and is treated with moisture-proof, anti mold, and anti salt spray. The insulation performance is excellent and reliable, and the mechanical strength is high. All terminals are insulated, waterproof, and fireproof wrapped, making the motor have excellent moisture-proof and insulation capabilities. To prevent the insulation resistance of the motor winding from decreasing due to condensation caused by temperature changes in the motor chamber during the operation of the mixer, non dissipative anti condensation measures will be adopted in the design of the mixer. Before assembling and sealing the motor, the stator winding of the motor is heated and dehumidified. After assembling and sealing, the stator chamber is vacuumed and pressurized with a certain amount of 0.1MPa nitrogen gas to eliminate the presence of air and water molecules in the chamber. This eliminates the condensation phenomenon caused by the temperature difference between the inside and outside of the casing reaching the critical condensation temperature during the cooling process of the stator chamber after the motor is stopped. As a result, the insulation of the winding is always maintained within a high resistance range, reaching and exceeding the specified values of relevant standards, so that the water pump unit is always in a normal state.

Develop and master the operational techniques of submersible mixers

Determine the critical impeller speed for suspending particles

Based on the characteristics of sewage and sludge, simulate the actual treatment situation, use commonly used calculation formulas and computer fluid dynamics software, and determine the critical speed of particle suspension on the basis of meeting the experimental conditions of the formulas.

During the installation and positioning process of the mixer, the pool type should be fully considered

In order to make installation and maintenance more convenient, the structure of the mixer will be designed to be more robust and compact, reducing the footprint, and allowing for flexible adjustment of the horizontal and vertical angles of the mixer jet without the need to discharge water from the pool, as well as quick installation and disassembly of the submersible mixer; Develop an installation system for submersible mixers based on various processes, tank types, and mixers for different purposes, modularizing the installation operation to make installation easier.

After experimental testing, the investment cost of the improved and optimized main equipment of the submersible mixer has been determined

Reduce by more than 30% compared to current similar equipment; The service life is longer than that of similar domestic equipment currently in use

An average increase of over 15%; Reduce operating costs by more than 5%. Blender efficiency and reliability

The performance has been improved, and the efficiency of the unit has increased by 5% to 8% compared to similar domestic products. blender

*The working time has increased to 3 years, and the overall service life of the machine has reached 15-20 years.