Mechanical Seals

Flexibox Mechanical Seals

Flexibox is a leading supplier of mechanical seals for all applications, but specialising in the Marine and Oil & Gas sectors. Flexibox Ltd was founded in 1945 by F. B. Porges and Manchester Oil Refinery to manufacture and sell mechanical seals.


Norton Wells has supplied Flexibox mechanical seals for over 40 years, and can supply the full product range, including:

Flexibox FFET Cartridge Mechanical Seal

The compactness of the FFET cartridge seal ensures that it will fit all ANSI and DIN stuffing boxes and offers an ideal upgrade from packing. The FFET is a robust cartridge seal used for a variety of duties from chemicals to oil and water, and for many abrasive and crystallizing duties. It is ideal for use on top-entry mixers, where the liquid product may not provide continuous cooling and lubrication of the seal faces. The use of premium seal face materials ensures low heat generation and dry-running thermal stability. On top-entry agitators a design variation is available for use on hygienic applications.

  • Heavy-duty drive.
  • Stationary flexible unit permits high tolerance to solids.
  • Stationary external spring improves tolerance to clogging.
  • Indirect positive sleeve/shaft drive prevents shaft damage.
  • Easy, fast and reliable installation as a pressure-tested preset unit.
  • Multi-functional gland plate.


PRESSURE LIMITS Dynamic: 300 psi(g)/21 bar(g)

Hydrostatic: 435 psi(g)/30 bar(g)

SPEED LIMITS 5000fpm/25m/s

The Flexibox R Series (including R00R/L, R10R/L, R20R/L, R30R/L) Mechanical Seal


The Flexibox R series mechanical seal is commonly used in many different industrial and marine applications. The R Series can be specified with carbon, silicon carbide and tungsten carbide faces. The R series is available in many different configurations to suit the specific application, please see below.

The Flexibox R0OR (right hand spring) and R0OL (left hand spring) mechanical seal utilises a parallel spring, designed to locate directly onto a shaft.

The Flexibox R1OR (right hand spring) and R1OL (left hand spring) mechanical seal utilises a parallel spring with a split sleeve and washer which locates onto the shaft.

The Flexibox R2OR (right hand spring) and R2OL (left hand spring) mechanical seal utilises a parallel spring with locating collar which secures onto the shaft using grub screws.