MECO Seals for the Plastics Industry

Aaron Kress

MECO Seals for the Plastics Industry

MECO seals are a consistently reliable sealing solution in the plastic production industry. The fully split EP Type 2 and EP Type 3 seals are popular options for polymer dryers and extruders and can be custom engineered for your machines and processes. Switching to MECO seals from traditional packing seals can often reduce a machine’s necessary runtime by improving vacuum containment and efficiency. Torque load from MECO seals is typically lower than that of packing, so they can also save costs by reducing motor current. Additionally, they help eliminate product loss by effectively sealing hazardous process solvents that are often used in plastic production. The EP seal’s self-adjusting design also offers extended service life between rebuilds to help minimize downtime for maintenance.

MECO EP Type - 2:

The EP Type 2 is a great choice if you have:

High runout

Ambient to moderately high temperatures

Low to moderate speeds

Infrequent thermal fluctuations or shaft growth / shrinkage

Infrequent pressure / vacuum fluctuations

Infrequent axial thrust

MECO EP Type - 3:

The EP Type 3 is a great choice if you have:

High runout

Ambient to high temperatures

Low to high speeds

Frequent thermal fluctuations or shaft growth / shrinkage

Frequent pressure / vacuum fluctuations

Frequent axial thrust

Process Factors that can Impact Seal Choice:

Nonuniform Movement of Shaft and Vessel:

Nonuniform movement of a machine's shaft and vessel can have several different causes:

The shaft and vessel may expand or contract at different rates if they operate at different temperatures or are heated at different rates, as is often the case with dryers.

Pressure/vacuum cycles may cause the vessel’s end wall to flex, resulting in nonuniform movement between the vessel and shaft.

Some machines, like extruders, may experience axial thrust during startup and shutdown.

The EP Type 3 is specifically designed to accommodate dissimilar movement between the vessel and shaft by allowing the drive collar to slide axially within the seal while still driving the seal’s rotors.


Shaft speed is always an important consideration when designing shaft seals, and this is especially true for the ever-increasing speeds of modern extruders. Faster applications impart more starting torque and generate more heat. In faster applications, the locking collar of the EP Type 3 is a better option than the EP Type 2’s elastomer drive to ensure that the rotors don’t slip during a high torque startup. Additionally, the EP Type 3’s seal face loading is more consistent and predictable than elastomer driven seals, allowing for better thermal control.

Why MECO Seals:

MECO seals are an excellent way to be proactive about product loss. Leaking seals are not only a nuisance that degrade your working environment, but they can also have a significant effect on process efficiency and safety. Unlike packing and lip seals, MECO seals are non-abrasive to shafts and are designed for minimal purge gas consumption. MECO’s fully split designs significantly reduce install and rebuild times, and with proper maintenance, can save on costly downtime with their high reliability. Improved seal integrity also enhances environmental safety by containing toxic process materials. A MECO seal today keeps emergency maintenance away!