QJB Submersible Mixer

Du'an Environmental Protection QJB Low-Speed Submersible Mixer is suitable for various water treatment processes and industrial applications where uniform mixing and reaction of solid-liquid two-phase or solid-liquid-gas three-phase media need to be maintained. It is mainly composed of a submersible motor, gear reducer, spiral propeller, sealing system, hand-operated hoisting mechanism, installation system, and electrical control devices.

QJB Low-Speed Submersible Mixer Model Description

QJB------Low-Speed Submersible Mixer (Submersible Propeller)

1.5-----Motor Power (KW)

4-----Motor Poles

42-----Propeller Diameter (mm)

2-----Number of Blades

1800-----Rated Speed (r/min)

S/P-----Material: S stands for stainless steel, P stands for polyurethane 

Du'an Environmental Protection Submersible Mixer Technical Performance Requirements:

The submersible mixers produced by Du'an Environmental Protection can be fully installed on the original mounting brackets without stopping water flow on-site.

All electrical interfaces of the submersible mixer are consistent with the on-site electrical control equipment interfaces to avoid causing faults in the electrical control system.

Submersible Mixer Performance and Structure:

The submersible mixer mainly consists of a two-blade propeller, gear reducer, submersible motor, and underwater sealed cable.

The output power of the submersible mixer ensures thorough mixing in the tank without significant sedimentation, meeting the required hydraulic and flow conditions.

The submersible mixer is installed on a bracket at the bottom of the tank via guide rails, allowing free lifting along the guide rails without the need to drain the tank during installation or maintenance. The entire weight of the submersible mixer is supported by the lifting bracket, which can withstand the thrust generated by the mixer.

Each submersible mixer must operate continuously at a maximum submersion depth of 20 meters underwater, while also supporting intermittent operation and resuming operation after prolonged shutdowns. Throughout operation, the mixer ensures smooth, vibration-free performance without jamming.

Housing Material:

The housing of the submersible mixer is made of high-quality gray cast iron GG25 or better, with a design thickness sufficient to withstand loads. The surface is smooth and free of pores, with a compact structure. All water-sealed surfaces are sealed with nitrile rubber O-rings.

Propeller Blade Material:

The propeller is two-bladed, made of polyurethane or fiberglass with an internal metal frame and an external protective coating, designed for handling conventional wastewater. It features a non-clogging, self-cleaning design with swept-back hydraulic balance. The propeller offers excellent hydraulic performance, promoting the flow of wastewater in tank channels.

The blades are "flexible" and capable of absorbing changing hydraulic loads. Each blade is mounted in a socket on the hub side via a cast iron shaft. The hub is fixed to the shaft end with a single key, sealed with a protective cap, and secured with a locking washer system.

Main Shaft Material Description:

The motor shaft and propeller shaft are connected via a gearbox. The shafts are made of wear-resistant stainless steel and can withstand all axial and radial loads. The propeller shaft is fully protected by mechanical seals, O-rings, and radial seals, isolating it from the mixing medium to prevent corrosion.

Bearing Description:

All bearings in the submersible mixer are high-quality, maintenance-free bearings with long-term grease lubrication, capable of handling axial and radial loads. The design life of the bearings is no less than 100,000 hours.

Shaft Seal or Mechanical Seal:

A mechanical seal and two radial seal rings are installed between the mixer gearbox and the hub. The radial seal rings are placed on bronze sleeves, providing additional protection for the mechanical seal and facilitating replacement. The shaft seal system includes a sealed oil chamber where the mechanical seal operates. A pair of radial seal rings is also installed between the motor chamber and the gearbox. The mechanical seal is maintenance-free and can rotate clockwise or counterclockwise without affecting its sealing function. The mechanical seal is made of silicon carbide or tungsten carbide, offering high mechanical strength and resistance to thermal shock, with a medium pH range of 4-10. The sealing material is nitrile rubber, known for its strong tear resistance and long service life. The design life of the mechanical seal exceeds 25,000 hours.

Submersible Motor Description:

The submersible motor is a three-phase squirrel-cage induction motor. The motor has an IEC IP68 protection rating and an insulation class of F, 155°C. The rated power of the motor ensures that the submersible mixer does not experience overload during operation. The motor can be started more than 10 times per hour. The motor shaft and rotor undergo dynamic and static balance tests. The motor is designed to operate in environments up to 40°C (104°F), capable of submersion and continuous mixing of liquids at 40°C, with an average stator winding temperature rise not exceeding 80°C. To monitor the temperature of each phase winding, thermal switches are installed in each stator winding coil, set to open at 130°C. The thermal switches are connected to the control cabinet and linked to control relays.

The motor and cable can operate continuously at a maximum submersion depth of 20 meters without losing their waterproof performance (meeting IP68 protection rating). The submersible motor is adequately cooled by the surrounding medium without relying on cooling jackets or external cooling systems. Additionally, the motor chamber is filled with insulating oil to ensure excellent insulation and cooling performance, preventing water leakage and motor burnout.

Underwater Sealed Cable Description:

The motor is equipped with a submersible sealed cable that includes both control and power cores. The motor has a separate, reliable cable entry. The cable complies with IEC standards and is provided with sufficient length to connect to the junction box or local control cabinet without splicing. The cable enters the terminal chamber using a reusable double-compression rubber sleeve seal, ensuring quick cable replacement. The cable seal is specially vulcanized to prevent liquid ingress into the motor due to cable sheath damage. The cable outlet is axial, flush with the outer surface of the motor housing, and secured with cable clamps to prevent movement due to water flow and avoid snagging during lifting. Both the motor and cable can operate continuously at a 20-meter submersion depth without losing waterproof performance.

Gearbox Description:

The submersible mixer is driven by an efficient planetary gearbox. The gearbox housing is integrated with the mixer housing, with a smooth transition to the hub and motor housing, ensuring high flow stability and excellent hydraulic characteristics, thereby improving the overall efficiency of the submersible mixer. The gearbox is equipped with high-precision, high-efficiency, low-load two-stage planetary gears made of high-wear-resistant alloy steel. The gearbox is filled with oil to lubricate and cool the transmission system. The gearbox brand is Shuntian or SEW. The design life is no less than 100,000 hours.

Monitoring System Description:

Three series-connected thermal switches are installed in the three-phase stator windings of the submersible mixer to monitor stator temperature rise. Thermal protection activates at 130°C, triggering an alarm and stopping the motor. The submersible mixer is equipped with a leakage sensor to detect leaks in the sealed oil chamber, preventing water ingress and motor damage. The leakage sensor is an electrode-type sensor, with signals monitored by a protection relay that triggers an alarm if water enters the motor.

Main Material Description:

The materials used in the submersible mixer are suitable for industrial wastewater treatment requirements.

Anti-Corrosion Coating Description:

All materials used in the manufacture of the submersible mixer are suitable for the corrosive environment of industrial sewage plants. Unprotected or non-corrosion-resistant materials are treated according to general technical requirements.

Submersible Mixer Technical Parameters:

Other Optional Accessories or Requirements

The submersible mixer is equipped with six sets of hand-operated hoisting devices (including steel cables and three-prong hooks) installed on the original lifting brackets. Some steel cables and hooks can be reused, with replacements and supplements provided based on on-site conditions. The hoisting device material for underwater parts must be stainless steel 304 or better, and for above-water parts, stainless steel 201, 304, or 316 or better. The hoisting device allows flexible forward and reverse operation, with immediate braking upon stopping, and automatic brake release during manual operation. The hand crank of the hoisting device must have an anti-loosening structure to prevent detachment.

The submersible mixer comes with a two-year warranty. During the warranty period, on-site or remote guidance is provided for maintenance. If a non-human-caused failure occurs during the warranty period, repairs will be arranged, and the warranty period for that mixer will be recalculated from the date it is put back into service after repair. If the same failure occurs twice or more for the same mixer during the warranty period, a free replacement with a new mixer of the same model will be provided.

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