Neles® butterfly valve, series BM

Zero leakage with double block and bleed full metal sealing

Metso's Neles® Mapabloc high performance butterfly valve with double block and bleed sealing system, is developed for ethylene plants to optimize the process of the transfer and decoking gas lines. The valve is designed to prevent all operation problems of traditional gate valve designs, such as coke accumulation and jamming due to high temperature differentials. The valves are in service world-wide in various ethylene plants.


High operational reliability, best thermal expansion resistance  - works in all process conditions

Maximized process uptime, faster transition to decoking mode and fast operation

Compact and low weight construction – no extra piping support needed

Flexible plant design - suitable for all installation directions and high temperatures up +600 ºC


  • Steam purging in seat area for continuous protection and cleaning, bearing protection as an option
  • Two piece shaft design for maximized capacity
  • Patented position indicator for highest process safety
  • Double block and bleed (DBB) sealing system for hydrocarbon and oxygen segregation
  • Compact and solid design
  • 100% fluid segregation
  • Block function with steam
  • High corrosion and abrasion resistance
  • Cobalt based alloy sealing surfaces and disc edge protection
  • Fire safe design
  • Gate valve face to face length
  • Zero leak construction prevents the back flow of the process gas to cracker furnace
  • Minimized OPEX - maintenance free up to 5 years
  • Optimized maintenance process for maximized process uptime



  • Ethylene cracking
  • Steam cracking
  • Oil and gas




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