Abstract: In apparatus for polymerizing high-pressure ethylene to produce polyethylene, a tubular reactor is connected to a source of solution to the tubular reactor. This solution includes one or more catalysts which promote the polymerization reaction. Within the tubular reactor, a peak temperature occurs in proximity of the point at which the catalysts are introduced. If the catalysts are introduced at more than one point, peak temperatures will result downstream of each of such points. For various reasons, the peak temperatures are displaced along the tubular reactor and a plurality of thermocouples are distributed at spaced positions in the tubular reactor to measure the temperatures at the positions at which the peak temperature might occur. These thermocouples generate signals which are fed into a gating arrangement which selects the peak signal which is compared in a comparator circuit with an adjustable or selectable signal representative of the peak temperature which is desired.

Abstract: In apparatus for polymerizing high-pressure ethylene to produce polyethylene, a tubular reactor is connected to a source of high pressure ethylene. An intensifier supplies an initiator solution to the tubular reactor. This solution includes one or more catalysts which promote the polymerization reaction. Within the tubular reactor, a peak temperature occurs in proximity of the point at which the catalysts are introduced. If the catalysts are introduced at more than one point, peak temperatures will result downstream of each of such points. For various reasons, the peak temperatures are displaced along the tubular reactor and a plurality of thermocouples are distributed at spaced positions in the tubular reactor to measure the temperatures at the positions at which the peak temperature might occur.