Based on long period observation and thinking, Brick creates the concept of “Three levels of logical requirements reflecting the safety and reliability of HVLS fans”:

A) Avoid fracture of blade

B) Avoid blade free fall if blade broken

C) Avoid fatal losses in case of free fall

Brick invents Al-Pc Complex Balde and Blade Interconnect Grills, which perfectly interprets the levels

• Avoid fracture of blade: the plastic enclosure imbedded aluminum skeleton reduces 40% in weight, no metal resonance, to relief the tension pressure on fixing position, all the measures cut down the chance to fracture.

• Avoid free fall of broken blade: twofold device were emplaced: Blade Interconnect Ring and Blade Interconnect Grille, which will hold the broken blade in the air by adjacent normal blades.

• Avoid fatal losses in case of free fall: Every blade was connected by three pieces of nylon cord with adjacent blades, even if the nylon cord broke accidently at some place, the blade was hold by other two cords which would provide enough time for people underneath to escape.