Impregnation Regimes of Pine Wood Assortments with Oily Antiseptics

Abstract

Technological properties of oil impregnations used in the manufacture of sleepers and poles of power transmission lines made of soft hardwoods are investigated. The aim is to optimize the parameters of wood modification during the production of railway sleepers and poles of power transmission lines and to increase their service life. The analyzed factor is the absorption depth across the fibers. A laboratory impregnation unit with an autoclave with an operating pressure of up to 20 atm was used. The oily antiseptic in the volume of 10 liters is heated by tubular electric heaters up to the temperature of 110 °С. The installation by its purpose is equivalent to the work of autoclave in the wood impregnation shop. At different modes, 25 samples of sleepers and 25 samples of power transmission poles were impregnated. The duration of the process is from 2 to 4 hours. The standardized antiseptic content of 19 % is provided by the pressure of 10–14 atm at the duration of the samples holding time of 60 min. Heating of the workpiece turned out to be the most influential factor on the depth of absorption – both for sleepers and poles. It is shown that the normal depth of impregnation is provided at a wood temperature of at least 70 °C for coal oil, as its viscosity is halved. For absorbent oil such dependence is not observed, its viscosity depends little on temperature. This temperature should be recommended for absorbent and shale oils, as the minimum allowable difference between the temperature of the impregnating agent of 110 °C and the temperature of the wood of 70 °C should not exceed 40 °C to prevent cracking of the wood. Of the 6 options for antiseptics, the following oils are recommended for use: coal oil, absorbent oil, Shuberkol komir and anthracene oil. For them impregnation regimes for sleepers and power transmission line supports are developed. At exposure of sleepers and poles blanks in vacuum with 0.2 atm rarefaction during 40 min oil leakage from blanks after the end of impregnation is completely excluded. For citation: Shamaev V.A., Medvedev I.N., Russu A.V. Impregnation Regimes of Pine Wood Assortments with Oily Antiseptics. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 6, pp. 136–148. (In Russ.). https://doi.org/10.37482/0536-1036-2023-6-136-148