摘要 |
A plastic material extruder having a barrel and an outer sheath with heating and cooling means in the outer sheath is disclosed, together with means for maintaining the temperature of the inner barrel, including two temperature sensing devices, one on the barrel and one on the other sheath, the sensing devices connected to control circuitry which actuates the heating and cooling means to maintain a temperature gradient between the two sensors by sensing the temperature change from the barrel and adjusting the set point of the sensing device on the sheath.
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