GB1378191A - Drying of timber - Google Patents

Abstract

1378191 Drying apparatus GKN BIRWELCO Ltd E H A BARNES and M D A RICHARDSON 30 May 1973 [6 April 1972] 15910/72 Heading F4G Apparatus for drying timber comprises a closable kiln chamber 1, Fig. 1, having air inlet and outlet apertures, an air blower 7, an air heater 9 and ducting connecting the apertures and the blower and heater, such that, in use, heated air is blown through a stack of cut timber in the chamber 1, the air circulation being substantially in closed circuit and such that a positive pressure is maintained in use throughout the kiln chamber 1. The latter is formed between inner side walls 2A, 2B, Fig. 3, which are louvred over substantially their whole areas, and between a fixed end wall 5A, Fig. 2, and a rolling shutter door 5B, Fig. 3. Plenum spaces 4A, 4B are formed between respective inner walls 2A, 2B and outer walls 3A, 3B. Ducts 6A, 6B are provided, the blower 7 is connected by a duct 8, Fig. I, to the heater 9, the air is heated by an oil burner 10, a duct 11 connects the heater 9 to the duct 6A, an exhaust gas flue 9A leads combustion gas from the heater 9 to atmosphere, the blower 7 is driven by an electric motor 7A via a belt 7B, and a control panel 12 is provided. In use heated air in the chamber 1 circulates from the heater 9, duct 11, duct 6A, plenum space 5A and louvred inner wall 2A to the kiln chamber 1 and returns, via the louvred inner wall 2B, plenum space 4B, duct 6B, blower 7 and duct 8, to the heater 9. Thus air is blown in through the inner wall 2A and out through the inner wall 2B and a positive pressure exists within the chamber 1. An adjustable air outlet valve 13, Fig. 2, communicates with the duct 8, which is at the location of highest pressure in the air circulation path, and an adjustable air inlet valve 14 is placed near the bottom of the wall 5A, this being at the location of lowest pressure.