DRYING PLANT, PARTICULARLY FOR TIMBER

摘要

The plant comprises a refrigerating system acting on the recycle air, including an auxiliary evaporator exposed to external air whereby the system may operate as heat pump. The valves controlling the system have a position in which the auxiliary evaporator (50 E/C) is rendered operative while the dehumidifying evaporator(40) is rendered inoperative. The outlet port (20) of the drying chamber comprises a by-pass section (20') which has associated therewith a first damper (46) by which the by-pass air flow is either recirculated to the condenser (38) or discharged to the outside through the auxiliary evaporator. A second damper (44) is provided to admit external air to the condenser (38) when the first damper (46) connects the by-pass section (20') with the auxiliary evaporator. Temperatures as high as 65-70.degree.C are practically achievable in the manner in the drying chamber (10) by the effect of "heat pump"; the performance factor of the heat pump is extraordinarily high and may correspond to 5750 - 6000 Cal/kWh when the external air temperature is above about 15.degree.C. (Fig.1 for publication).