Apparatus for sensing the temperature of a thermoplastic sheet in a differential pressure forming machine

摘要

Apparatus the temperature of a thermoplastic sheet including a hollow wave guide having a bend therein, for receiving and transmitting infrared energy emitted by the sheet between a sheet heater at a sheet forming station and differential pressure forming apparatus at a forming station. One end of the hollow channel is mounted adjacent the sheet. At the opposite end of the hollow channel, a plurality of infrared energy sensors is mounted for sensing the infrared energy. Infrared sensors include mechanism for converting the infrared energy to electrical energy to operate a control system which controls the level of electrical power to the heater and thus controls the temperature of the sheet.