MASON SAFEFLEX Flexible Rubber Expansion Bellows

Applications – Non-Seismic

  • Fans
  • Pumps
  • Air Compressors
  • Air Handling Units


  • 5kg – 18144kg


  • 25mm – 127mm


  • Height Saving Brackets
  • Seismic Snubbers
  • Bolted Base (SLF-H)

MASON SAFEFLEX Flexible Rubber Expansion Bellows

SAFEFLEX EPDM and KEVLAR reinforced flanged rubber bellows are moulded and vulcanised in hydraulic presses. This high pressure process produces a smooth finish product with outstanding adhesion between the cover, reinforcement and tube.
Most of the competition still use Natural Rubber impregnated Nylon tire cord between sulfur cured EPDM covers and tubes. This construction becomes brittle wit age at higher temperatures, so we moved from Nylon to Kevlar as Kevlar has a higher modulus that minimises swell and elongation with outstanding temperature tolerance up to 120oC.
Another serious problem with flexible expansion joints is the body pulling out of the flange. Our solution is to wrap the tire cord around a solid steel ring in place of the cable. Sealing pressure is amplified by the ductile iron flanges that rotate inward around solid exterior stops. The split flanges are hooked together to prevent spreading. In over 25 years of production we have not a had the ring pull through.

Available in both single sphere and twin sphere, please refer to data sheet for flange options and pressure ratings.

Nominal Bore

  • 20mm – 50mm (SFU)
  • 40mm – 600mm (SFEJ/SFDEJ)

Options – SFU

  • 304 Stainless Steel Threaded Ends (SFU-SS)
  • Sweat ends for copper pipe (SFU-CT)
  • Brass Threaded Ends (SFU-BT)
  • Nominal Pressure – 14bar – 121oC with pressure correction

Options – SFEJ/SFDEJ

  • Single Sphere (SFEJ) or Twin Sphere (SFDEJ)
  • Refer to data sheet for pressures
  • British standard, ASA, Din, PN and JIN bolt pattern flanges available.
  • Control Rods and Control Cables
  • Reducing Expansion Joints (SFDCR)

Please contact your Mason Mercer representative to discuss your requirement prior to ordering to ensure correct selection.

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