Device for drying wood particularly trees in leaf, bamboo canes in leaf and similar plants carrying out by heat

SUMMARY OF THE INVENTION The combustion chamber (21) is formed in the lower part of the combustion gas generator (2) and the exhaust gas passage (3) extending from the upper part of the combustion gas generator (2) to the upper part of the arable chamber (1). (7) extending the waste gas line (6) extending from the lower part of the drying chamber (1) to the combustion gas return line (5) and the gas flow control unit located at least one combustion gas return line ( 5) and a spent gas outlet line (6).

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HU 209 986 B

Scope of the description: 6 pages (including 1 page figure)

HU 209 986 Β

FIELD OF THE INVENTION The present invention relates to an apparatus for the drying of wood, in particular the heat-drying of deciduous trees, deciduous bamboos and the like, in order to produce within a short time, dried wood, dried bamboo and the like. dried plants whose water content is stabilized.

After harvesting, the water content of deciduous trees and the like is high and usually contains many insects and their eggs. In the production of construction or furniture wood, deciduous wood must be dried and chemically treated to kill insects and their eggs.

During the drying process, the deciduous trees have been so far subjected to the natural drying, during which the deciduous trees have been left in the yard for a long time, such as 3-5 years. During this time, logging workers often had to move the tree to help it dry. However, leaving the tree in the yard for such a long time is a very bad investment, and the tree has to be protected from insects.

Under these circumstances, several drying methods have been proposed so far to dry the wood in a short amount of time. One such conventional drying method is vacuum drying, and another known method is heat drying, in which a field chamber is used and hot air is supplied to it.

However, wood produced by conventional known drying processes is disadvantageous because it prevents the wood from forming cracks that absorb moisture and therefore deform the wood. Such wood results in natural drying.

In order to solve problems associated with the usual rapid drying process, another method, heat drying, has been suggested. In conventional heat-drying, the deciduous wood is first placed in a drying chamber which is obtained by burning the wood or the like, is introduced directly. The deciduous tree is brought into contact with the hot burning gas to dry it and to remove the insects from the heat and various smoke elements from the burning gas. They kill insects and their eggs in the tree without undergoing chemical treatment or undergoing deformation of the dried tree.

Married. 59-129,373 and 60-103,281. Japanese Patent Specifications disclose a conventional heat plowing process in which the wood is placed in a treatment chamber, the upper part of which is exposed to hot air flow and the lower part subject to cold air flow to dry the wood. These patents also describe a system for carrying out the process, but which is of low efficiency. In the process when large amounts of deciduous wood are placed in the treatment chamber in order to increase the efficiency of the treatment, the water content of the resulting dry wood will be variable, which means that the quality of the product or dried wood cannot without being stabilized.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the shortcomings of known methods and apparatus. According to the present invention, this object is solved by providing an apparatus for efficient drying of a large amount of wood having a sealable drying chamber, with an inlet duct for supplying fresh air to the combustion chamber and a combustion chamber in the lower part of the combustion gas generator. and a passage of the combustion gas from the upper part of the combustion gas generator to the upper part of the drying chamber, from the lower part of the drying chamber to the chimney, a spent gas discharge line, a combustion gas return line from the lower part of the drying chamber to the combustion gas generator, and a gas flow control unit arranged in at least one combustion gas return line and a spent gas discharge line.

According to the invention, the combustion gas return line can be directly connected to the combustion gas generator. It is also possible to connect the combustion gas return line to the air intake line.

In a preferred embodiment of the device according to the invention, the gas flow control unit, which is located at least one exhaust gas discharge line and the combustion gas return line, consists of a combination of a fan and a damper. It is also possible for the gas flow control unit to consist only of a fan or damper.

Preferably, the fan and / or damper is located in an air intake duct of the system. However, the air intake duct is not required for the system. It is also advantageous if a fan is provided with at least one air intake duct, exhaust gas exhaust duct or flue gas return duct.

In the apparatus for drying hardwood and the like according to the present invention, the waste wood and the like are burned in the system's combustion gas generator to produce the hot combustion gas carried by the smoke. The hot combustion gas is then introduced into the upper part of the drying chamber through the combustion gas inlet.

In the drying chamber, the hot combustion gas passes through the deciduous wood accumulated in the drying chamber downwards to the heat and dry the wood, and then reaches the lower part of the drying chamber, from where the combustion gas flows into the exhaust gas conduit and discharges into the atmosphere.

In such an operation, the portion of the combustion gas exiting the lower portion of the drying chamber is circulated so as to enter the combustion gas recirculation line through which the recirculated portion of the combustion gas returns to the combustion gas generator, where it is used to regulate the combustion rate of the fuel. working with fresh air.

operation of the drying system of the present invention requires the production of a combustion gas that is substantially free of oxygen. In addition, it is undesirable that the temperature of the combustion gas is too high. Therefore, flue gas recirculation in the system is advantageous. If the combustion gas is one

If the system is circulated in the system, steam and volatiles can be recovered from it before the gas leaves the system via a chimney. The volatiles thus obtained are again incinerated in the apparatus before being released into the atmosphere via the chimney. This combustion contributes to the reduction of air pollution caused by volatile substances in the combustion gases and also leads to cost savings as the volatiles are used as fuel in the system.

DETAILED DESCRIPTION OF THE INVENTION The invention will be described in greater detail with reference to the drawing, which schematically illustrates a longitudinal section of an exemplary embodiment of the apparatus of the invention.

As shown in the drawing, when drying deciduous trees and the like, the wood is placed in a drying chamber 1 and accumulated. The drying chamber 1 may be sealed and positioned so as to be adjacent to the combustion gas generator 2, the upper portion of which is in communication with the upper portion of the plow chamber 1 via passage 3.

The lower part of the combustion gas generator 2 forms a combustion chamber 21 in which a suitable fuel such as waste wood or like can be burned to produce hot combustion gas. An inlet duct 4 is connected to the combustion chamber 21 of the combustion gas generator 2 through which fresh air flows into the combustion chamber 21.

A rotatable damper 41 is incorporated in the end piece of the air inlet conduit 4 for controlling the amount of fresh air introduced into the combustion chamber 21 of the combustion gas generator 2.

The bottom of the drying chamber 1 is connected in several places to the return gas line 5 which is connected to the air inlet line 4.

A fan 51 is provided in each of the combustion gas return lines 5 which draws the combustion gas from the drying chamber 1 and delivers it to the combustion gas generator 2, and a damper 52 to control the flow rate of the combustion gas extracted from the combustion chamber 1.

One exhaust pipe 6 is connected to one of the corners of the drying chamber 1 in a direction transverse to the flue gas supply passage 3. As a result, the exhaust gas discharge line 6 is located at the point of the drying chamber 1 furthest from the flue gas inlet 3. The exhaust gas discharge line 6 leads to a chimney 7, from where the spent gas flowing through the discharge line 6 enters the atmosphere.

A rotary damper 61 is disposed in the exhaust gas discharge line 6 to control the amount of exhaust gas flowing into the horn. In the operation of the wood drying apparatus according to the invention, it is primarily a suitable conveyor such as a rotary conveyor that conveys the deciduous wood to the drying chamber 1, where the deciduous wood is accumulated on the floor of the drying chamber. The drying chamber 1 is then closed so as to be hermetically sealed, and a suitable fuel such as waste wood or the like is burned in the combustion chamber 21 of the combustion gas generator 2 to create a spinning gas that flows from the combustion gas generator into the combustion chamber 3 across.

At this time when the flap 6 of the exhaust gas outlet duct 6 is closed, the hot combustion gas gradually fills the drying chamber 1 to occupy the space previously contained in the drying chamber 1. The air is drawn into the combustion chamber 21 of the combustion gas generator 2 by the fan through the combustion gas return lines. As long as the drying chamber 1 is filled with the combustion gas, the resulting hot combustion gas circulates through the system.

As the temperature of the drying chamber 1 is increased by the heat from the hot combustion gas, the oxygen content of the atmosphere in the drying chamber 1 decreases and restricts the fuel flow to the combustion chamber 21 of the combustion gas generator 2 so that the rate of temperature rise in the drying chamber 1 decreases.

Under these conditions, the damper 61 in the exhaust gas discharge line 6 opens slightly to allow a portion of the combustion gas to escape into the chimney 7 via the discharge line 6. As a result, fresh air is introduced into the combustion chamber 21 through the air inlet conduit 4 and the amount of fresh air thus introduced corresponds to the amount of combustion gas escaping from the drying chamber 1. By controlling the amount of fresh air introduced into the combustion chamber 21, the combustion rate of the fuel in the combustion chamber 21 can also be controlled.

In addition, when both fans 51 and dampers 52, which are located in the combustion gas return ducts 5, are actuated during operation, the portion of the combustion gas in the drying chamber 1 is forced through the system to enter the combustion chamber 21 of the combustion gas generator. the fresh air introduced into this combustion chamber 21 is diluted with the recirculated combustion gas. In this way, the oxygen content of the atmosphere in the drying chamber 1 is kept low. As a result, the oxygen content of the atmosphere in the drying chamber 1 is unchanged and the temperature in the drying chamber 1 is uniform.

As stated above, during the drying operation, the drying chamber 1 is filled with a hot combustion gas which has a low oxygen content and a stable temperature distribution. The hardwood can be dried very efficiently in the drying chamber 1 of the system. Volatile gases from the deciduous wood in the drying chamber 1 are circulated during the drying operation to enter the combustion chamber 21 of the combustion gas generator 2 where these volatile gases are co-incinerated with the fuel such as waste wood to form a combustion gas . The present invention prevents the atmosphere from being contaminated by these volatile gases.

In the outlined embodiment, the exhaust gas discharge line 6 is directly connected to the corner of the drying chamber 1. However, it is conceivable that part of the exhaust gas discharge line 6 forms the combustion gas return line 5.

It is also possible for exhaust gas to be exhausted

EN 209 986 Β should be constructed as branch line for combustion gas return line 5.

In the field implement according to the invention, the control unit consists of fans 51, dampers 52 or only dampers 41 and 61. However, this gas flow control system can also be replaced by speed control fans, where the speed of rotation can be controlled.

In the drying apparatus according to the invention, since the oxygen content of the hot air in the drying chamber 1 is low, the temperature distribution is uniform and stable, and the high quality dried wood can be produced in high yield.