Engineers at the Battelle Memorial Institute are patenting a special vortex gun they developed. It might find use firing rings of ionized air at fires to clear smoke or sending rings of pesticide at hard-toreach wasp nests or other pests. And police might use it to disperse tear gas into a crowd without the danger of a canister hurting anyone or the risk of a miscreant hurling the canister back at the police.
The gun forces air or some other gas down its barrel at speeds of at least 90 mph. Friction of the gas against the inside of the barrel causes a thin layer of the gas to roll forward on itself, forming a ring. The developers liken the effect to a tornado formed into a donut. The ring revolves, letting it stay together rather than disperse. Tests show rings can stay together for at least 50 yards and travel at 60 mph. The vortex rings are even stable in crosswinds, but they tend to turn into the crosswind.