Introduction to E-style seals 

E-style seals are external mechanical double seals. It’s located within a stuffing box assembly that is fitted over the pump’s rotating shaft. The stuffing box assembly consists of a standard backplate that is fitted with a housing called a flush housing or a stuffing box. The double mechanical seal sits inside the housing over the shaft, with another small plate on the other end as a stuffing box cover.  

A water flush inlet is mounted on the side of the stuffing box assembly, and the water outlet is on the top. This is to ensure that the whole system is full, and your seal will always be encapsulated in water.  

E-style seals are used on certain centrifugal pumps, such as the C216, C+216, and other larger C-Series models. While the lobe pump, circumferential piston pumps, and the twin-screw pump use an equivalent seal configuration, we don’t call them ‘E’ seals. The ‘E’ designation is specific to the C-Series, so on those pumps, they’re identified as double mechanical seals. 

Why use an E-Style seal? 

This type of seal is a great choice for slurries, sticky and abrasive products, and heavy-duty vacuum applications. Examples include: 

Food and Beverage Processing: Hot honey, liquid sugar, high-gravity wort, juice concentrates, and liquid chocolate. You can’t use a water flush on chocolate, as they do not mix well. Instead, you would use a vegetable oil to flush your seal to keep it clean. 

Pharmaceuticals: Water for injection, where zero contamination is critical. In this case, the product itself would be used to flush the seal. 

Conclusion 

E-style seals are external mechanical double seals that are installed within a stuffing box assembly. A water flush is used to flush the assembly full of water, keeping your seal constantly lubricated and cool. This style of seal is great for tough applications like slurries, sticky and abrasive products, and heavy-duty vacuum applications.