Centrifugal Pumps – construction
Pumps are categorized into several types according to operating principle and construction. Centrifugal pumps move fluid inside the pump chamber (casing) using centrifugal force generated by a rotating impeller.
Subsequently centrifugal pumps can be categorized into two different pump designs:
Magnetic drive centrifugal pumps
Mag drive pumps are magnetically driven centrifugal pumps without shaft seals.
An impeller incorporating a permanent magnet is rotated and driven by the magnet mounted on the motor shaft.
The magnetic force from the drive magnet causes the magnet on the impeller to rotate.
Since there is no shaft seal passing through the casing, the pump chamber is completely isolated and hermetically sealed, which eliminates the potential for leakage of toxic and aggressive fluids.
The elimination of leakage makes the pump well suited for pumping toxic and aggressive fluids, as it does not pose a threat to people and the environment.
Shaft seal centrifugal pumps
Shaft sealed centrifugal pumps have a pump shaft passing through the casing to transmit the motor power to an impeller in the casing.
The power generated from the motor is transferred to the impeller mounted on the shaft, which transform the power into torque and pressure, causing the pump to move the fluid.
To prevent the fluid from leaking, the opening where the shaft enters the casing has a shaft seal, such as a mechanical seal or gland packing.
However, these seals are not completely leak-free and with time, seals may in addition become worn-out, causing an even greater leakage.
Leakage of aggressive and toxic fluids may be dangerous and pose a threat to people and the environment.
