Chesterton DirectFit Series—Single & Dual Seals

Chesterton DirectFit Series—Single & Double Seals
Seals Designed to Fit Sulzer™* APP/APT and NPP/NPT Series Pumps

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Chesterton DirectFit™ Series mechanical seals are designed to fit the Sulzer* APP/APT and NPP/NPT series process pumps, providing an easy and convenient upgrade in sealing performance without modification.

  • ​​​​​Incorporates the latest in seal face design technology to minimize heat generation and optimize performance in the most difficult process services
  • Ideal for paperstock, hot condensate, liquors, solvents, and evaporation services in a variety of industries

​* Sulzer Ltd. is in no way associated or affiliated with A.W. Chesterton Company. This reference to Sulzer pumps is intended solely to identify products of this other manufacturer for which A.W. Chesterton Company designed its DirectFit seals to be compatible.

Chesterton DirectFit
High-torque, monolithic seal faces
Designed to fit Sulzer* APP/APT and NPP/NPT pumps
Adjustable barrier/buffer fluid ports
Automatic centering
Field repair-capable​​​​​​​
Sizes30 mm to 90 mm (1.18" to 3.5")
Pressure711 mm (28") Hg Vacuum to 20 bar g (300 psig*)
Temperature–55° C to 300° C (–67° F to 570° F)
Speed25 m/s (5000 fpm)
*Seal pressure capabilities are dependent on the fluid sealed, temperature, speed, and seal face combinations.Temperature is dependent on elastomer type. For operation outside the limits and additional materials, consult Chesterton Mechanical Seal Engineering.



Technical Material Reference (English) Material Reference (English)pdf
Brochure: Chesterton Direct-Fit Single and Dual Seals (English) Chesterton Direct-Fit Single and Dual Seals (English)pdf
Installation Instructions: DirectFit Dual Seal (Multiple Languages) Instructions: DirectFit Dual Seal (Multiple Languages)pdf
Brochure: Chesterton DirectFit Seal Imperial (English) Chesterton DirectFit Seal Imperial (English)pdf
Installation/Rebuild Instructions: DirectFit Single Seal (Multiple Languages) Instructions: DirectFit Single Seal (Multiple Languages)pdf