Lens expansion joints

Lens expansion joints are single-walled metal expansion joints in single or multi-shaft variations with lower expansion and very robust construction. These consist of one or several semi-circles that are welded into corrugation peaks and troughs with circular seams.

HKS triple-convolution stainless steel lens expansion joint, DN 700
HKS lens expsion joint made of stainless steel
Lens expansion joint parameters

Bellows materials

  • C steel (S235JR)
  • elevated temperature steels (P265GH, 16Mo3, 13 CrMo 44, etc.)
  • high-alloyed steel (1.4401, 1.4541, 1.4571, 1.4828, etc.)
  • various Ni alloys (2.4858, 2.4858, etc)

Connection parts

  • without additional connection parts
  • Weld ends
  • Fixed/Swivel flanges


  • Fluids
  • Gases
  • abrasive media and solids

Nominal widths

  • DN50 to DN9000 (in circles)
  • any size in oval cross-sections

Operating temperature

  • up to 1000°C

Pressure levels

  • PN1 to PN100

Construction shapes

  • circular
  • oval
  • Special shapes

Inner protection tube

  • Variations with or without inner guide tube and/or
  • Guide tube possible

Movement absorption

  • axial
  • lateral
  • angular
  • Combinations thereof
Production of lens expansion joints