an apparatus for producing acetylene, C2H2, by decomposing calcium carbide, CaC2, with water. As a result of the reaction CaC2 + 2H2O = C2H2+ Ca(OH)2 at 20° C and 101,325 newtons per sq m (N/m2), or 760 mm of mercury (mm Hg), 235-285 liters (l) of C2H2 are obtained from 1 kg of industrial CaC2; theoretically 1 kg of CaC2 gives 370 l of C2H2. The CaC2 is decomposed to produce the acetylene in a gas generator from which the gas passes into a gas collector (gas holder).
Acetylene generators are divided into low-pressure types, with pressures no higher than 0.01 meganewton per sq m (MN/m2), or 0.1 kilogram-force per sq cm (kgf/cm2); medium-pressure types, with pressures of 0.01-0.15 MN/m2, or 0.1-1.5 kgf/cm2 (used for welding); and high-pressure types, with pressures of more than 0.15 MN/m2, or 1.5 kgf/cm2 (not generally used for welding). An acetylene generator can produce 0.8-150 cu m of acetylene per hour. Because of the danger of explosion, the generators are installed in a separate generator room, which is isolated from other factory buildings. Such generators produce acetylene that is saturated with water vapor, thus giving a lower flame temperature during welding. Consequently, for small amounts of welding the use of dissolved acetylene, which comes in steel tanks filled with a porous mass saturated with acetone, is advisable. This acetylene contains no water vapor, gives a hotter flame, and is explosion-proof.
K. K. KHRENOV