What are they air horn used at refinery?

Air Movers, or air horns, are used wherever there is a need to disperse fumes, move air into confined spaces, cool men working in elevated temperature conditions, or cool machinery or products with a blast of directed air. Common applications are found in refineries, chemical plants, utilities and congeneration units, metal fabrication plants, paper and pulp plants, shipyards, the marine industry and the steel industry.