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What is a mechanical seal in a pump?

Intended to keep internal fluids or gases from escaping the pump, mechanical seals are devices that secure the gap within the rotor. Each of the two sections of the mechanical seal is connected to a certain part of the pump: the stationary section is attached to the pump housing, while the rotating segment is attached on the rotating shaft.

Choosing mechanical seals instead of compression packing is highly beneficial not only to you, but to your pumps as well.

• Handles high pressures from the fluids
• Little to no friction between the moving parts
• No wear and damage, requiring minimal maintenance
• Less to no leaking from the pump

Type of mechanical seals.

Different mechanical seals are available, with each one best suited for a specific application or function.

• Pusher and non-Pusher types are simple and cost-effective options that can tolerate a little amount of misalignment and vibration. They differ in the assembly used in the middle, with pusher types employing a spring that is axially mounted on the shaft assembly. Non-pusher types, on the other hand, prefer sealed bellows over the spring attachment to push the halves together.
• Balanced types are perfect for high-pressure setups and have low lubrication fluids. Unbalanced types are better-suited to setups with a lot of vibration and misalignment.
• Conventional types are great as retrofits for mechanisms that originally did not use seals, though may require some engineering and maintenance.
• Cartridge types are easy to replace and provide static sealing to the shaft and the housing. Easy to maintain, these are the preferred sealing type for newer machines.

Why do mechanical seals fail?

As with most pieces of machinery or equipment, mechanical seals can still fail when mishandled or not used properly. Here are some common things to avoid for an efficient mechanical seal:

• Vibration, caused by misaligned or imbalanced pumps, can damage the seal and reduce its service life.
• Placing couplings on the pump shaft using hammers can affect the seal and could create damage.
• Omitting or improperly using the mechanical seal flush plan can contaminate the seal, leading to possible overheating or erosion.
• Thermal shock, brought by allowing the pump to dry up, can cause the seal to shatter.
• Not following the recommended start-up procedures of the pump can bring damage not only to the seal, but to other parts as well.
• Picking the wrong mechanical seal for the pump accounts to some common errors on installation and use.