Secondary explosions tend to cause the most damage in an unprotected system, rather than the first explosion. This tends to be due to insufficient explosion isolation in the ducting between vessels or connecting plant equipment in plant at risk. Often , weak enclosures such as dust collectors, cyclones, bins , silos and bucket elevators are only protected with explosion venting, and while this may relieve some over-pressure or decouple the explosion somewhat , however there is still a greater risk of further damage if explosion isolation measures are not implemented to prevent the propagation of explosions between vessels. The explosion will not selectively travel only through the explosion vent opening. The explosion will enter through all the available openings. If the explosion enters connecting ducting and is allowed to travel to connected equipment , the hazard becomes very dangerous. The plant equipment can be protected by the use of explosion isolation products.
Active isolation systems (as opposed to active isolation valves) require the use of an explosion detector and control panel, and are comprised of either or both chemical and mechanical isolation solutions.
Active explosion protection with mechanical isolation involves triggering a high-speed valve to form a mechanical barrier in the pipeline. This barrier can protect against flame as well as pressure propagation into connected vessels. Valve designs such as ” explosion protection guillotine valves / slide valves eg Rico RSV ” or explosion protection float valves eg Rico ESI-P
Chemical isolation uses an explosion suppressant powder ( eg Food Grade Sodium Bicarbonate or mono – ammonium phosphate ) discharged into the duct work between interconnected vessels to suppress the propagating flame front before it has the opportunity to travel and achieve an enhanced explosion.
· IEP Technologies Active System Components: Control Units (EX100-1, EX200), Dynamic Explosion Pressure Detector, Infrared & Ultraviolet Infrared Detectors, and Static Explosion Pressure Detector.
· IEP Technologies Chemical Isolation: PHRD Suppressor
· Rico Ventex Explosion Isolation Valves: ESI-P, RSV-D, RSV-G, RSV-P and REDEX Slide.
Passive explosion isolation relies solely on the pressure wave from the explosion to trigger a the isolation mechanism. These solutions function without detection or control units.
· Brilex Isolation Valves: BPF-M and RSK (discontinued)
· Brilex Explosion Diverter: REXS
· Thorwesten Vent Explosion Diverters: STT and DES
· IEP Technologies Isolation Valve: ProFlapPlusII and IsoFlap
· Rico Ventex Isolation Valves: New Gen, ESI-D, ESI-E, ESI-C, and REDEX Flap