API 685 – Centrifugal Pump (Sealless)

A sealless centrifugal pump is a type of pump that uses centrifugal force to generate flow and does not have a mechanical seal to contain the fluid being pumped. This makes sealless pumps an attractive option for handling hazardous or toxic fluids, as there is no risk of leakage due to a faulty seal.

Sealless pumps are typically made from corrosion-resistant materials such as stainless steel or exotic alloys, making them suitable for handling corrosive fluids. They are also often designed with a casing that is cooled by the pumped fluid, allowing them to handle high temperatures.

There are two main types of sealless pumps: magnetic drive pumps and canned motor pumps. Magnetic drive pumps use a magnetic coupling to transmit torque from the motor to the impeller, while canned motor pumps use a rotor that is suspended in the fluid being pumped.

One of the main advantages of sealless pumps is their ability to handle hazardous or toxic fluids without the risk of leakage. This makes them ideal for use in chemical plants, oil refineries, and other industrial settings where the risk of leakage could have serious consequences.

Sealless pumps are also generally more reliable than pumps with mechanical seals, as they have fewer moving parts and are less prone to wear and tear. This results in lower maintenance costs and longer lifespans.

However, sealless pumps can be more expensive to purchase and maintain than their sealed counterparts, as the materials and design are more complex. They may also be less efficient, as the lack of a mechanical seal means that some of the energy from the motor is lost to the pumped fluid.

Despite these drawbacks, sealless pumps are a valuable tool in many industrial settings due to their ability to safely handle hazardous or toxic fluids. With proper maintenance and care, they can provide reliable service for many years.