# 1995 Edinburgh
Heat transfer coefficients for splay cooling in the manufacture of blue, yellow and black PE-80 and PE100 MDPE pipes are determined by measuring pipe surface tempemhtres in the annealing zones between splay tanks, and then fitting a computer simulation of the cooling process by adjustment of heat wander coefficients. Data were collected fmm six exhusion lines producing pipes fmm 63 to 315mm diameter. T d e r coefficients were found not to depend simcantly on pipe diameter, or on the variations in spray arrangements hetween exhusion lines; however, a si@icant and consistent reduction in values was found for successive tanks along the cooling line. In the first (vacuum) tanks a value of about 1500 w/m2 K was fo\md; in the second 500 w/m2 K and in the third 250 Wlm K. There is no conclusive evidence that polymer material affects the values, though somewhat higher mmfer coefficients were deduced for black PE-100.