Method for drying wood and an apparatus for the implementation thereof

Abstract

The invention relates to the sector of wood conversion, in particular, to the method of timber drying and the unit using in practice thermo-vacuum-impulsive treatment. The method of timber drying by means of repeated alternation cycles including the blowing of timber with heating medium operation at atmospheric pressure and heating the timber to average volume temperature 80 - 100 °C, impulsive (quick) vacuum treatment operation at pressure not more than 50 mm Hg during time not more than 10 s with pressing-out of free moisture from timber without water to vapour transition to reach stable constant value of timber temperature, vacuum relief to atmospheric pressure by means of heating medium supplying, at that timber blowing and vacuum relief are performed by using heat recuperating air with temperature 150-300 °C, and at manometer pressure not more than 0,07 MPa. The apparatus to work in practice the method for timber drying comprises two drying chambers connected through pipelines with quick-response valves to cooled receiver, which is placed in series to the second one and connected to vacuum pump through pipeline with vacuum lock. The first receiver is equipped with spiral-shaped guide devices for vapour-and-drop flow direction, which are installed at a tangent to inner diameter of receiver body. The drying chambers are connected to the system for preparation of hot heating medium supply. The method and the unit stimulate the drying process at simultaneous improvement of dried timber quality.

Description

technical field [0001] The invention relates to the field of wood treatment, in particular, the invention relates to wood vacuum drying technology, and the invention can be used in wood industry, wood treatment industry and other industries. Background technique [0002] The method currently used is pulsed vacuum drying of construction materials by means of repeated alternating cycles of heating, while the material is blown by means of heating medium and vacuum, and during each cycle the heating and vacuum are applied for a duration equal to the blowing time. There is adiabaticity between processing operations. Blowing was performed within 6 minutes at a temperature of 160° C. and at a moisture content of 15 g / kg by means of gas-air mixture operation. Vacuum treatment was performed within two minutes at a residual pressure of 300 mmHg (cf. a.c. USSR No. 1000701, class. F26B5 / 04, 1981 publication г.). The apparatus includes a drying chamber and a vacuum pump connected to a ...

AI Technical Summary

Problems solved by technology

[0003] Disadvantages of this method and this device include: high energy consumption due to the long time required to generate the vacuum and to carry out the drying operation; the poor quality of wood drying in the cross-sectional area; and the final moisture content along the The length of the pile is quite uneven

The above formula for determining the pipe diameter does not appear to be correct

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