Cast film machine ventilation system

For many years, the cast‑film production of polyimide films has relied on conventional equipment: a blower draws ambient air into a duct, where it is heated to 180–230°C by a heater before being fed into the cast‑film extruder. An exhaust fan then removes the spent gas—containing evaporated solvents—and cools it to ambient temperature using chilled water before discharging it. However, heating ambient air to 180–230°C and subsequently cooling it back down to room temperature consumes substantial energy, while the large volume of chilled water required for this process drives up both energy consumption and overall production costs.

To address the shortcomings of existing technologies, a ventilation system for a coating machine is provided that recycles waste‑gas heat, reduces energy consumption, and thereby lowers production costs.

The cast‑film machine ventilation system comprises a blower, a heater, an exhaust fan, and an exhaust‑gas cooling system. It is characterized by the further inclusion of a heat exchanger: the blower’s air outlet is connected to the heat exchanger’s air inlet; the heat exchanger’s air outlet is connected to the heater’s gas inlet; the heater’s gas outlet is connected to the cast‑film machine’s gas inlet; the cast‑film machine’s exhaust outlet is connected to the heat exchanger’s waste‑gas inlet; the heat exchanger’s waste‑gas outlet is connected to the exhaust‑gas cooling system’s gas inlet; and the exhaust‑gas cooling system’s gas outlet is connected to the exhaust fan’s gas inlet.

The cast‑film machine’s ventilation system recovers the thermal energy from exhaust gases to preheat the incoming air, thereby reducing process energy consumption, decreasing cooling water usage, and lowering production costs.