Back pressure flap B-FLAP I

B-FLAP I is a mechanical device designed to prevent propagation of flame and pressure between pieces of technology equipment during explosion. B-FLAP I is, together with other safety measures, a part of a system that protects technologies intended for operation in an explosion danger environment. Economical solution of protection against propagation of explosion between pieces of technology equipment is the B-FLAP I back flap.


  • Wide variety of sizes from DN 100 to DN 800
  • Mechanical device that does not need electrical energy or
    activation system
  • Low pressure losses
  • High pressure resistance
  • Optional position indicator
  • Optional signalization of dirt on flap seating surface
  • Simple installation, inspections and maintenance
  • Low maintenance costs
  • Mechanical shut-down when the flap closes
  • Suitable for technologies working with light metal dust
  • Possibility of complementing with the mechanism RPD
    (Reducer of Pressure Drop)
  • Can be applied to piping with elbows.

Equipment suitable for explosion isolation in pipe of:

  • Filters
  • Silos
  • Reservoirs
  • Mills
  • Mixers
  • Cyclons
  • Spray driers
  • and other devices with danger of dust explosions

Diagram of the B-FLAP I instalation on a pipe

Dust explosion on a pipe without/with back flap

In normal operation, the back pressure flap is open due to the flow of air volume inside the piping, or it is kept in the open state by the mechanism RPD which ensures opening the flap independently of the air volume flow. This solution reduces pressure loss in the piping system significantly.

In the case of explosion, the back flap is closed and locked, thus preventing the spread of the explosion to other parts of the equipment or production technology.



  • Construction steel
  • Stainless steel


  • Komaxit (RAL 3000 – red)

Technical specification of back flap

Price offer

I agree to the processing of personal data I want to know more

Completed projects

I want to help with the selection