Tham khảo tài liệu 'volume 06 - welding, brazing and soldering part 18', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Acetylene Acetylene is the most widely used cutting gas. It burns hotter than any of the other common fuel gases maki indispensable for certain jobs. The volume of oxygen consumed per volume of acetyláneQenẩbustion occurs in stages. In the small inner cone at the tip of the torch acetylene burns with feed-line oxygen. This reaction gives blistering amount of heat the tip of the inner cone is the hottest part. Burning continues in the outer envelope o flame in a cooler blue-colored region. 1 Most oxygen for this reaction comes from the air surrounding the flame. OF-ttpsas of oxygen needed for acetylene .1 to burn completely abouW comes from the air and 1 part from line oxygen. A neutral flame recommended for mam cutting consumes equal volumes of line oxygen and acetylene. In practice operators may raise the line oxygen rc 1 . . _ . . . . a proportion that produces an oxidizing flame. The inner cone contracts and becomes sharply defined. This i hottest flame attainable with acetylene or with any other raw fuel gas. The triple bond in acetylene makes it the h burning gas. In cutting of steel operators should adjust the acetylene-to-oxygen ratio to produce a neutral flame though it is below the highest possible temperature. A neutral flame minimizes oxidation and carburization of the I metal. Users sometimes use the hotter oxidizing flame for piercing at the start of a cut. Acetylene is unstable at room temperature and moderate pressure and can explode under a blow even witho presence of air or oxygen. For safe storage and handling it is dissolved in acetone. A typical cylinder is filled with hi porous clay which holds the acetone. Acetylene forced into the cylinder saturates the acetone. When the cylinder opens acetylene vaporizes above the acetone solution. The regulator limits outlet pressure to 105 kPa gage press psig or less. Cylinders for acetylene should be handled with care. Safety requires them to be placed upright to prevent acetone s from entering the .
