Activity: Talk or presentation › Oral presentation
The process of pipe belling applied to thermoplastic sewer pipes is a special type of thermoforming of plastics. The process can be subdivided into three basic steps: heating, forming and cooling of the pipe end. In this paper the heating step is described by means of a physical model using two optical quantities, reflection and penetration depth, for the description of the radiation absorption. The reflection is measured directly using a specially equipped spectrometer. The penetration depth is calculated from the measured quantities reflection and transmission. Numerical calculations based on the mathematical model are performed for different radiator temperatures and for two different heat transfer coefficients on the inner pipe surface. The temperature distribution in the pipe end is calculated as a function of radius and time. Additionally, minimum and a maximum heating time and temperature homogeneity are determined.