GB1432010A - Apparatus and processes for the fluid impregnation of timber - Google Patents

Abstract

1432010 Impregnating timber C G W MASON 25 June 1973 [3 July 1972] 30077/73 Heading DIP An apparatus for longitudinal fluid impregnation of a log comprises a cap 10 for enclosing one end of a log L so as to define a fluid treatment zone, members 30 inserted through apertures in the side wall of the cap for positioning it on the log, a seal arrangement comprising a resiliently compressible sealing means 18 sandwiched between first and second rings 17, 19 for encircling the log, the second ring having or being associated with means 20 for retaining it against movement on the log, means 13, 21, 22 for exerting pressure on the end of the log so that compression will be applied to the sealing means, and means 14, 24, 25 for introducing a pressurised log-treating fluid into the treatment zone for the fluid to be forced along within the log. The sealing means preferably comprises an elastomeric ring of U- or W-shaped cross-section made of natural or silicone rubber. It may be stretched to pass over the end of the log. The seal may be improved by spreading paste on the surface of the log. The rings 17 and 19 may each consist of two hinged semi-circular halves lockable together, the ring 17 being a loose fit about the log and abutting the member 30, and the ring 19 conforming closely to the contours of the log and filling the space between the log and the inside surface of the cap. The retaining means 20 preferably comprises a chain which can be tightened about the log. The sealing assembly 17-19 is preferably upstream of the members 30 but may alternatively be located downstream of them in which case a sub-atmospheric pressure is applied to the other end of the log. The members 30 preferably comprise spring loaded bayonet pins or press-studs located radially around the periphery of the cap. The cap may be made of fibre glas-polyester resin or steel and may have a diameter up to 250 cm., the material being selected so that the cap can support a pressure up to 14 kg/sq. cm. The means 13, 21, 22 comprise a hydraulic ram supplied with fluid along lines 14, and having a piston 21 actuatable to press against the end of the log. A line 24 having a gauze 25 covering its outlet is provided for passing fluid into the treatment zone. The fluid may be impregnation fluid. Alternatively, the means 13, 21, 22 may comprise a member which is activated by pneumatic or mechanical pressure. A pressure release valve 16 is provided to enable air to escape from the treatment zone during filling with fluid. In operation the rings 17, 18 and 19 and the retaining chain 20 are positioned around the log, and the cap passed over the log and sealing assembly, and retained in position by the members 30. The sealing ring 18 is then set by actuating the piston 21 of the ram 13 with fluid along a line 14 to abut against the end of the log, the ring 19 thereby compressing the resilient ring 18 against the ring 17 which abuts the members 30, to seal against the inside of the cap and the surface of the log. Impregnating fluid is then introduced into the treatment zone via line 24 to be forced along within the log.