RU2319086C1 - Method for lumber drying and installation for its realization - Google Patents

Abstract

FIELD: forestry and wood-working industry, in particular, lumber drying practice.

SUBSTANCE: the method for lumber drying consists in heating of it in a drying chamber with the aid of convectors, collection of the moisture evaporable inside the chamber on condensers with a subsequent removal of the condensed moisture outside of the condensed moisture outside of the chamber. The processes of heating to a temperature not exceeding 35-45°C and condensation are accomplished without any heat exchange with the environment simultaneously in response to the signals of the temperature-sensitive and moisture-sensitive element under the control of the computer according to the programs developed for lumber of each type. The lumber drying installation has a drying chamber with converters (heaters), condensers installed in it and provided with a system for collection, canalization and removal of the condensed moisture. The drying chamber is made heat-and-moisture insulated from the environment. The condensers represent tubes (radiators) cooled by water or air of the required temperature, or thermoelectric Peltier modules cooled by the electric current flowing through them, installed vertically on each side of the lumber pile. The chamber is provided with air temperature and relative humidity sensitive elements in the chamber, lumber temperature and humidity sensitive elements, connected to the control circuit.

EFFECT: reduced power consumption by the drying process, enhanced capacity of the process and drying quality, provided collection of the evaporable moisture for its further processing.

2 cl, 1 dwg

Description

Technical field

The invention relates to the forestry and woodworking industries, in particular to the technology of drying lumber.

State of the art

A known method and device for drying wood (RU No. 2128811, IPC F26B 7/00, published on April 10, 1999) The invention provides for heating wood in a sealed chamber with steam under atmospheric pressure, having a temperature lower than the boiling point of moisture contained in the wood, condensation and removal of released moisture, resinous substances and gases, and the temperature of the vapor is maintained constant. But not more than 110 ° C, for a time sufficient to remove resinous substances to a predetermined threshold concentration. After that, the steam in the chamber is replaced with air at the same pressure and at a temperature of 0-10 ° C below the temperature of the steam and air is ejected from the chamber through adjustable exits; during the entire drying period, air parameters are maintained at a constant evaporation rate (temperature, pressure, flow rate and humidity) such that the rate of moisture separation is maximum, and when going to the drying period with a falling evaporation rate, the listed air parameters are changed so that at each given time interval the speed lagging was maximum. Drying is stopped when the desired final moisture content of the wood is reached. This method is taken as a prototype. The device comprises a platform for placing a stack of layered wood. Means of condensation and removal of the vapor-gas medium, means of moisture removal, controls, temperature sensors. Pressure sensors, humidity sensors and an interface connected to the controller, and, in addition, contains means for creating and maintaining conditions for the maximum release rate of tarry substances, carbon dioxide and methane during steaming wood, and means for creating and maintaining conditions for maximum moisture separation during air drying as during a period of constant evaporation rate, and in a period of falling evaporation rate, moreover, as a means of maintaining conditions of maximum rate of release of tarry substances, gases and moisture and They use a single control complex that is taken outside the chamber and includes a steam generator-humidifier, a compressor, a flow regulator — a flow meter, a heater, and a controlled valve connected to the controller; it contains carbon dioxide and methane concentration analyzers that are also connected to the controller, and the moisture condenser is outside chamber and made in the form of a utilizer of harmful substances released during the drying of wood.

The disadvantages of the known technical solutions is the high drying temperature and, as a result, high energy consumption, marriage during drying, the need for steaming wood.

Known dryer for lumber (RU No. 21115871, IPC F26B 9/06, 5/04, publ. 07/20/98), which is taken as a prototype containing a horizontal cylindrical body, a circulation fan, a heating volume for heating the drying agent, a drying volume with lumber located in fibers along the direction of travel of the drying agent, the condensation volume in which the plate heater, cooled by cold water, is located, a vacuum pump partially suctioning the spent drying agent after the condensation volume, heating atelny volume is formed as an annular space defined by the cylindrical side-bar situated concentrically casing annulus evenly spaced tubes along the generatrices of the cylindrical body and the side-bar connected to the external boiler, in the inner part of the cylindrical side-bar mounted trolley loaded top lumber into a cylindrical shape. Condensation volume with a plate heater, cooled by cold water, is tightly closed on the sides along the generatrix and open on both ends, on one end of the drying volume. Under operating conditions, the drying agent moves only in one direction in the drying volume with lumber towards the condensation volume.

The disadvantages of the known drying method and devices mentioned above are:

- high energy intensity of the process, due to the need to remove humidified air outside the drying chamber, while a significant part of the thermal energy supplied to the chamber for heating the lumber in order to intensify the drying process is lost;

- environmental pollution by wood fumes;

- loss of valuable substances contained in the output moisture;

- a significant amount of scrap among the dried lumber.

Disclosure of invention

The objective of the invention is to develop such a method and a device that implements it, which would provide a technical result in the form of reducing the energy intensity of the drying process while increasing the productivity of the process and the drying quality, as well as the ability to collect evaporated moisture for its further processing.

This technical result is achieved thanks to the present invention, a method for drying lumber, which consists in heating them in a drying chamber using convectors, collecting evaporated moisture inside the chamber on condensers, followed by the removal of condensed moisture outside the chamber, while the processes of heating to a temperature of not more than 35- 45 ° С and condensation are carried out without heat exchange with the environment at the same time according to the signals of temperature and humidity sensors under computer control according to the programs developed nym for each type of timber.

The same technical result is achieved thanks to the present invention, which provides an installation for drying lumber, including a drying chamber with convectors (heaters) installed in it, condensers and equipped with a system for collecting, draining and removing condensed moisture, while the drying chamber is heat-insulated from the environment, and condensers are pipes (radiators) cooled by water or air of the required temperature, or Peltier thermoelectric modules cooled by leaking m therethrough electrocution mounted vertically on the sides of the stack of sawn timber, wherein the chamber is provided with temperature sensors and relative humidity in the chamber, temperature and humidity sensors timber connected to the control circuit.

Convectors are made in the form of heat pipes placed at the bottom of the chamber.

The control circuit includes a computer or controller with a set of control programs and switching devices.

The novelty of the claimed technical solutions is due to the ability to significantly reduce the consumption of thermal and (or) electric energy while improving the process productivity and drying quality, as well as the ability to collect evaporated moisture for its further processing. This is due to the fact that the process of heating lumber and the simultaneously occurring process of condensation of the moisture evaporating at the same time do not require the release of heated steam into the environment. Due to this, maintaining the temperature in the chamber above 35-45 ° C is not required, which makes the process economical and creates conditions for a mild drying mode and, accordingly, significantly reduces the possibility of marriage in the form of cracking and warping of lumber.

According to the scientific, technical and patent literature, the authors are not aware of the claimed combination of features aimed at achieving the objectives, and these solutions do not follow clearly from the prior art, which allows us to conclude that technical solutions correspond to the level of inventions.

The invention is illustrated by the drawing, which shows a General view of the installation for drying lumber that implements the proposed method.

The implementation of the invention

The present invention can be implemented using the device shown in the drawing. The installation includes a drying chamber 1 with convectors (heaters) 2 installed in it, condensers 3, and equipped with a system for collecting, draining and removing condensed moisture 4. The drying chamber 1 is thermally moisture insulated from the environment, and the condensers 3 are pipes (radiators) that are cooled water or air of the desired temperature, or Peltier thermoelectric modules, cooled by the flow of electric current through them, mounted vertically on the sides of the stack of lumber 5, while the chamber 1 is equipped with tchikami temperature and relative humidity in the chamber 6, temperature sensors and humidity timber 7 connected to the control circuit 8.

Convectors 2 are made in the form of heat pipes placed at the bottom of the chamber 1. The control circuit 8 includes a computer or controller with a set of control programs and a switching device 9.

The method of the present invention is implemented in the installation according to the drawing as follows.

Inside the drying chamber 1, lumber (for example, boards) is placed, assembled in a stack 5 in a short order, with gaskets between the rows. After closing the gates of the chamber, the control system is started according to the program corresponding to the type of lumber and geometric dimensions. The method of drying lumber consists in heating them in the drying chamber using convectors 2, collecting the evaporated moisture inside the chamber on the condensers 3, followed by the removal of condensed moisture outside the chamber, while the processes of heating to a temperature of no more than 35-45 ° С and condensation are carried out without heat exchange with the environment at the same time according to the signals of temperature and humidity sensors 6, 7 under the control of a computer according to the programs developed for each type of lumber. (Software is not the subject of invention). The method does not include steaming wood.

The control system 8, based on the signals of the temperature and humidity sensors 6, 7, regulates the operating modes of the installation by changing the temperature of the heaters 2 and condensers 3. The moisture released on the condensers is discharged outside the chamber and collected in storage tanks (not shown in the diagram).

Although the present invention is described by way of examples of its implementation, the scope of the present invention is not limited to these examples, but is determined only by the claims taking into account possible equivalents.

Claims (4)

1. The method of drying lumber, which consists in heating them in a drying chamber using convectors, collecting evaporated moisture inside the chamber on condensers, followed by the removal of condensed moisture outside the chamber, characterized in that the processes of heating to a temperature of no higher than 35-45 ° C and condensation they are carried out without heat exchange with the environment simultaneously according to the signals of temperature and humidity sensors under computer control according to the programs developed for each type of lumber. 2. Installation for drying lumber, including a drying chamber, with convectors (heaters) installed in it, condensers and equipped with a system for collecting, draining and removing condensed moisture, characterized in that the drying chamber is thermally moisture insulated from the external environment, and the condensers are pipes ( radiators), cooled by water or air of the required temperature, or Peltier thermoelectric modules, cooled by electric current flowing through them, mounted vertically on the sides of the stack lumber, while the camera is equipped with temperature and relative humidity sensors in the chamber, temperature and humidity sensors of the lumber connected to the control circuit. 3. Installation according to claim 2, characterized in that the convectors are made in the form of heat pipes placed in the lower part of the chamber. 4. Installation according to claim 2, characterized in that the control circuit includes a computer or controller with a set of control programs and a switching device.