RU2397413C1 - Method for wood drying - Google Patents

Abstract

FIELD: wood working industry.

SUBSTANCE: method for wood drying in chamber isolated from atmosphere includes heating drying agent with the help of heaters, facilities for heating and circulation of liquid high-temperature coolant connected in upper part of shell in parallel with manifold pipelines, reversible fans and flow dividers, providing for motion and distribution of drying agent along stack through diffuser channels, every of which is symmetrical to rows of stack gaskets, leveling moisture along wood section by moistening system with subsequent time delay, removal of drying agent from chamber into condensation facility and control of technological process by means of pressure, temperature and moisture control. The novelty is the fact that wood is moistened within the limits of 50-65°C depending on type and assortment of wood with water of temperature of at least 75°C, with subsequent time delay within the limits of 20-40 min., moisture is evaporated from wood by means of its heating to the temperature of at least 102°C, increasing wood temperature in stages of 2°C up to 118°C with delay at each stage within the limits of 10-30 min. by means of drying agent, heated up to temperature that exceeds current wood temperature, with value of not more than 10°C, until pressure in chamber is not more than 1000 mm of mercury column, drying agent is removed until underpressure in chamber reaches value of 600 mm of mercury column.

EFFECT: accelerated production of high-quality boards, timber in serially produced drying chamber without creation of vacuum pulse in it by intensification of wood drying process.

3 dwg

Description

The invention relates to accelerated drying of various species and cross-sections of wood equipment, providing moisture transfer through exposure to relatively high temperatures, moisture content and variable pressure.

Known, for example, a drying chamber (RF patent 2091684, Mcl F26B 5/04, publ. 1997), including a heating cavity, a cooling cavity, the inlet and outlet gas line, a condenser, a vacuum pump, a heat exchanger, a flow meter and a vortex the pipe.

The disadvantages of the known drying chamber can be attributed to the relatively low quality of the dried lumber due to the unevenness of its heating by constantly changing heated air at the beginning, end, top and bottom of the stack.

The method of drying wood and a device for its implementation are claimed to develop a variety of drying methods by making greater use of the structural base of the working chamber with the components set forth in RF patent 2334924, M. F26В 5/04 (publ. 2008), where the drying of wood is carried out in a chamber isolated from the atmosphere using heaters, reversible fans and flow dividers, providing movement and distribution of the drying agent along the stack through diffuser channels, each of which is symmetrical to the rows of gaskets .

Thus, the task to which the invention is directed is to expedite the receipt of high-quality boards, timber, etc. in a commercially available drying chamber according to the patent of the Russian Federation No. 2349424 without creating a vacuum pulse in it by intensifying the drying process of wood by combining the use of temperature gradients, moisture content and alternating pressure without the conditioning phase using auxiliary devices that remove the drying agent from the chamber through the main paths and a condenser made with the ability to move the liquid into the collector and return the dried steam for reuse.

This task is achieved by the fact that the method of drying wood in a chamber isolated from the atmosphere involves heating the drying agent using heaters connected in parallel to the upper part of the shell with main pipelines for heating and circulating liquid high-temperature coolant, reversible fans and flow dividers, which ensure movement and distribution of the drying agent along the stack through diffuser channels, each of which is symmetrical to the rows of stack gaskets, moisture leveling along the wood cross section a humidification system, followed by a time delay, removal of the drying agent from the chamber into a condensation means and regulation of the process by means of pressure, temperature and humidity control, according to the invention, the wood is moistened in the range from 50 to 65 ° C depending on the type and variety of wood with water at a temperature of at least 75 ° C, followed by a time delay ranging from 20 to 40 minutes, the evaporation of moisture from the wood is carried out by heating the wood to a temperature of at least 102 ° C, raising it in steps of 2 ° C wood temperature up to 118 ° С with exposure at each step in the range of 10 to 30 min, with a drying agent heated to a temperature exceeding the current wood temperature of no more than 10 ° С, until the chamber pressure reaches not more than 1000 mm Hg, removal of the drying agent is carried out until a vacuum of at least 600 mm Hg is reached in the chamber.

Uniform distribution of the drying agent over the slots of the stack by flow dividers formed by diffuser channels due to a gradually increasing cross-section to the side walls of the chamber symmetrically to the rows of stack gaskets, in combination with a drying device, fans and heaters mounted in diffuser channels connected in parallel with main pipelines means for circulating and heating a high-temperature liquid coolant, as well as removing the drying agent from the chamber through a condenser, see sheniya vacuum pump sending fluid into the condensate collection and steam through its drainage means for subsequent reuse provided together with strengthening and accelerating the drying process, a combination of high temperature heating and alternating pressure at a given temperature reduction in power consumption.

Thus, the combination of the above distinguishing features allows us to sufficiently improve the quality of wood drying using energy-saving technology, reduce drying time and use a commercially available drying chamber according to the patent of the Russian Federation 2334924 (publ. 2008), which reduces capital labor costs when launch into production.

The drawings show:

- figure 1 is a flow chart of equipment for drying the proposed drying method;

- figure 2 is a section aa in figure 1;

- figure 3 is a section bB in figure 2.

On the proposed according to the technological scheme (figure 1) equipment drying method is as follows.

A cart with lumber with an ambient temperature is loaded into the chamber 1, hermetically sealed.

Moisture is evaporated from the wood by heating the wood to a temperature of at least 102 ° С, raising the temperature stepwise through 2 ° С to 118 ° С with holding at each step for 10 to 30 minutes with a drying agent heated by a high-temperature liquid heat medium to a temperature reaching not more than 10 ° C from the temperature of the wood, to achieve a pressure in chamber 1 of not more than 1000 mm RT. Art., respectively, with the help of fans 4 mounted in the upper part of the shell 2 along its entire length in the diffuser channels 3, reversibly providing the movement of the drying agent through flow dividers 4, evenly distributing the flow along the stack, and heaters 5, connected in parallel with the main pipelines of circulation means 6, pumping a high-temperature liquid coolant from heating means 7 through heaters 5.

The softening and leveling of moisture along the cross-section of the assortment when the wood temperature reaches 50 to 65 ° C, depending on the type and assortment of lumber with hot water with a temperature of at least 75 ° C, is carried out by a humidification system 9 with a subsequent exposure of 20-40 minutes at each step.

The drying agent is removed from the chamber 1 through a mixing condenser 10 by a vacuum pump 11 until a vacuum of up to 600 mmHg is reached. with the supply of a steam pump separated by a water separator, a vacuum pump 10 to the means 12 for draining it for reuse.

Thus, accelerated evaporation of moisture uniform over sections of the stack is carried out when the temperature in the wood is kept in steps of 2 ° C from 102 to 118 ° C by a drying agent heated by a liquid coolant to a temperature reaching no more than 10 ° C from the wood temperature, followed by holding at each degree until the pressure in the chamber reaches not more than 1000 mm Hg and the removal of moisture in a misty-vapor state, to a vacuum in the chamber of at least 600 mm Hg By means of moisture transfer gradients in temperature, moisture content and pressure, the timber can be dried without internal stresses and deformations while preserving the natural color.

Claims (1)

A method of drying wood in a chamber isolated from the atmosphere, including heating a drying agent using heaters connected in parallel to the upper part of the shell with main pipelines of a means for heating and circulating a liquid high-temperature coolant, reversible fans and flow dividers, providing movement and distribution of the drying agent in a stack through diffuser channels, each of which is symmetrical to the rows of stack gaskets, moisture leveling along the cross section of the wood with a humidification system, followed by time delay, removal of the drying agent from the chamber to the condensation means and process control by means of pressure, temperature and humidity control, characterized in that the wood is moistened in the range from 50 to 65 ° C depending on the type and variety of wood with water at a temperature not less than 75 ° С followed by a time exposure ranging from 20 to 40 minutes, moisture is evaporated from the wood by heating the wood to a temperature of at least 102 ° С, raising the temperature of the wood in steps of 2 ° С to 118 ° С Exposure at each stage in the range from 10 to 30 minutes with a drying agent heated to a temperature exceeding the current wood temperature of no more than 10 ° C, until the pressure in the chamber reaches not more than 1000 mm Hg, the drying agent is removed until a rarefaction chamber of at least 600 mm Hg

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