Eyebrow coil jacket, a heat control apparatus of a reactor using the eyebrow coil jacket, and a method for manufacturing the heat control apparatus

A reactor including a reflux condenser, an outer wall having an outer surface, and a heat control apparatus, the heat control apparatus comprises a semi-circularly shaped pipe having a radius of curvature and a chord length that is 50 to 80% of the radius, the semi-circularly shaped pipe includes first and second edges along the length of the pipe, the edges defined by the ends of the semi-circular shape, wherein the semi-circularly shaped pipe is provided along the outer wall of the reactor such that the edges contact the outer surface, wherein the semi-circularly shaped pipe forms a spiral tunnel having a plurality of adjacent spirals surrounding the reactor, wherein the spiral tunnel is provided along the outer wall such that the first and second edges of the adjacent spirals are fixed to the outer wall by a single welding portion, wherein the reactor is a continuous or batch polymerization reactor for exothermic polyvinyl chloride polymerization, wherein the spiral tunnel is configured such that each contact point between the edges of the semi-circularly shaped pipe and the outer surface of the reactor defines a respective angle, wherein the angle is between a normal line of the outer surface at the respective contact point and a tangent line of the semi-circular shaped pipe at the edge at the respective contact point, wherein the angle is equal to or greater than 35° and less than 50°, and wherein the chord length of the semi-circularly shaped pipe is twice or more of a thickness of the outer wall of the reactor.