Leak Free Canned Motor Pump Shielding Pump Used In Power Plants

Principles and structural characteristics of canned pumps

A canned motor pump is a type of centrifugal pump that incorporates an integral electric motor and pump impeller into a single compact unit. Unlike conventional pumps, where the motor is separate from the pump and connected by a shaft, a canned motor pump eliminates the need for a separate motor, coupling, and mechanical seals.

The construction of a canned motor pump includes the following key components:

1. Stator and Rotor: The stator is the stationary part of the electric motor, consisting of windings that generate a rotating magnetic field when supplied with electrical power. The rotor is the rotating part of the motor, which is magnetically coupled to the stator and driven by the rotating magnetic field.

2. Pump Impeller: The pump impeller is mounted directly on the rotor shaft. It consists of curved blades that rotate with the rotor, imparting centrifugal force to the fluid and creating pressure to move the liquid through the pump.

3. Canning: The motor and impeller assembly is enclosed within a hermetically sealed housing known as the "can." The can is typically made of corrosion-resistant materials such as stainless steel and serves as a containment vessel for the pumped fluid and the motor.

4. Bearings: Canned motor pumps incorporate specialized bearings that provide support and stability to the rotor shaft within the can. These bearings are designed to handle the hydraulic and mechanical forces generated during pump operation.

5. Stator Cooling: To prevent overheating of the stator windings, canned motor pumps often feature internal cooling circuits. The pumped fluid flows through the cooling circuit, dissipating heat and helping to maintain the stator at an appropriate operating temperature.

Canned motor pumps offer several advantages over traditional pump-motor configurations:

1. Elimination of Shaft Seals: The hermetic sealing of the can eliminates the need for mechanical shaft seals, which are a common source of leakage and maintenance issues in conventional pumps. This makes canned motor pumps highly suitable for handling hazardous, toxic, or environmentally sensitive fluids.

2. Enhanced Safety: The absence of shaft seals reduces the risk of leaks, ensuring a higher level of safety for personnel and the surrounding environment. Canned motor pumps are commonly used in applications where leak-free operation is critical, such as in the chemical and petrochemical industries.

3. Compact Design: The integration of the motor and pump into a single unit results in a compact design, saving space and simplifying installation. Canned motor pumps are often used in applications where space is limited or where a small footprint is desired.

4. Improved Efficiency: Canned motor pumps can achieve high levels of hydraulic and overall efficiency due to the elimination of energy losses associated with shaft seals and couplings.

Canned motor pumps are widely used in various industries, including chemical processing, oil and gas, refrigeration, heat transfer systems, and nuclear power plants. They are particularly valuable in applications that require high reliability, safety, and leak-free operation.