RU2847991C1 - Device for drying wood materials - Google Patents

Abstract

FIELD: woodworking, furniture and other industries.

SUBSTANCE: drying of solid materials or objects by removing moisture from them, in particular devices for continuous movement of material with its heating by an electric, magnetic or electromagnetic field - heating using microwaves. The device for drying sawn timber comprises a chamber mounted on a support, in which the sawn timber is located, a means for moving the sawn timber, a microwave energy source, a blowing means, a moisture removal means, and a control means. The chamber is made in the form of a hollow prism, one of the faces is made in the form of a removable flat cover equipped with a blowing device. Microwave energy sources in the form of magnetrons are mounted in two rows on the side faces, with at least six in each row. Boxes for the blowing device and transformers are installed on the outer sides of the faces. The moisture removal device is located under the bottom edge of the chamber. The device for moving sawn timber is made of a reducer installed under the bottom edge of the chamber and interconnected with a trolley located inside on the bottom edge of the chamber with the possibility of reciprocating movement. The control device is designed as an electrical panel equipped with a control panel, and the chamber is connected to a vacuum pump equipped with a vacuum pressure gauge.

EFFECT: technical result is manifested in a reduction in the dimensions of the device, allowing it to be placed in an area of no more than six square metres, the possibility of manual loading without the use of lifting equipment and machinery, a reduction in the drying time of various types of wood, and ease of use.

3 cl, 8 dwg

Description

The invention relates to woodworking, furniture and other industries, in particular to the drying of solid materials or objects by removing moisture from them, in particular to devices for the continuous movement of material and its heating by an electric, magnetic or electromagnetic field - heating using microwave (ultra-high frequency radiation).

A device and method are known for treating wood and other fibrous materials in a hermetically sealed, heat-insulated chamber, comprising means for applying a given mechanical pressure to said fibrous materials, means for regulating conditions within said chamber, under which steam is formed in the center of said fibrous materials, and means for subsequently removing said steam; the means are additionally provided for painting, finishing, imparting fire resistance, laminating, molding, shaping, and increasing the density and tensile strength of said fibrous materials (Patent No. US4017980A. Published 1977-04-19).

However, the known device and method, despite being used for drying wood, have a complex design and are not intended for drying soft and hard wood species using microwaves.

An improved kiln for drying wood is known, which dries wood placed therein using the energy of electromagnetic waves of the highest frequency (microwaves). The kiln comprises a main scattering antenna having a structure in the shape of an inverted T; antennas scattering electromagnetic waves, which are made by connecting certain parts; connections for transmitting electromagnetic waves with conductive properties, which are made of aluminum and resistant to electromagnetic waves, and are located in the areas where the said antennas face each other; aeration pipes that pass into the chamber and suck air through a plurality of holes, which collect the said air and move it out; condensation pipes (copper), which collect water (Application No. WO 2011090448A1. Published 2011-07-28).

However, the known design is complex, has large dimensions, loading into the chamber is carried out using lifting equipment and machinery, and the drying time for various types of wood is quite long.

A device is known for drying and processing wood, comprising a sealed chamber with thermal insulation, a device for placing wood, a device for heating a gas medium, a device for circulating a gas medium inside the sealed chamber, consisting of a fan and a distribution device, an outlet device with a condenser, a temperature and humidity control system, in which the temperature and humidity control system is additionally provided with a gas medium pressure control system, the sealed chamber is thermally insulated, a device for placing wood, operatively combined with a distribution device, is made in the form of a container that provides, with the help of at least one fan, circulation of a gas medium flow, the device for heating the gas medium is located under the floor of the container, and / or along its sides, and / or above its ceiling, the outlet device is provided with a control valve, and the floor and ceiling of the container are provided with openings, the dimensions of which ensure the fulfillment of the condition S1 > S2, and S4 > S3, where S1 is the cross-sectional area of the fan outlet, S2 is the total cross-sectional area of the openings in the floor of the container, S3 is the total cross-sectional area of the openings in container ceiling, S4 is the cross-sectional area of the fan inlet (Patent No. RU 2182293. Published 10.05.2002).

However, the known device for drying and processing wood has a complex design, large dimensions, loading into the chamber is carried out using lifting equipment and machinery, and the drying time for various types of wood is quite long.

A device is known for drying wood products, comprising at least one drying chamber, units for feeding relatively dry and/or warm air into the chamber and removing more humid and/or cold exhaust air from it, conveyors located in the upper or lower parts of the chamber with a number of elongated, preferably vertically directed transfer elements installed between them, located in individual chambers at a distance from each other to form a large number of preferably vertical compartments, in which the material is products in the form of boards or planks, and the transfer elements have the shape of an eccentric, are installed with the possibility of rotation and ensure the placement of the material in the vertical compartments with the edges on top of each other with the possibility of their clamping (Patent No. 2092756. Published 10.10.1997).

However, the known device operates on a different principle, specifically by placing wood products vertically for drying and rotating them. Furthermore, it has a complex design.

A device for producing modified wood is known, which includes a microwave electromagnetic energy generator, a waveguide and a hot air blowing system. For this purpose, the waveguide consists of a metal cassette of a box-shaped cross-section and two horns in the form of truncated pyramids, the large bases of which are connected to the end walls of the cassette. In the horn, located between the generator and the cassette, a V-shaped electromagnetic energy diffuser is installed (Patent No. RU2151 691. Published on June 27, 2000).

However, the known device is intended for obtaining modified wood and is not intended for drying wood of various hard species.

A device is known for drying wooden parts, mainly boards, using microwave energy, comprising a device for moving the parts to be dried along a given trajectory, at least one source of microwave energy, one device for acting on wooden parts with microwave energy, a line transmitting microwave energy to this device, a device for blowing on the parts and removing suspended moisture, as well as a device for automatically monitoring the drying process, an optimal arrangement of the microwave energy source and the transmission line, a computer and a control unit, as well as a control unit, connected in series (Patent No. RU 2075709. Published 20.03.1997).

However, despite the fact that the known device is designed to increase the efficiency of drying wooden parts, it is not suitable for drying boards of various wood species, is large, and is not designed for installation in an area smaller than six square meters. Furthermore, it lacks the ability to load boards manually and has a relatively long drying time.

The objective of the present invention is to expand the range of dryers for various types of hard wood.

The technical result is manifested in the reduction of the device dimensions, allowing its placement in an area of no more than six square meters, the possibility of manual loading without the use of lifting equipment and machinery, a reduction in the drying time of various types of wood, and ease of use.

The stated technical result is achieved by the fact that in a device for drying lumber, comprising a chamber mounted on a support in which lumber is located, a means for moving lumber, a microwave energy source, a blowing means, a moisture removal means, a control means, the chamber is made in the form of a hollow prism having three faces in the form of planes, the fourth face is made in the form of a removable plane-cover equipped with a blowing means, on the side faces microwave energy sources are mounted in two rows, made in the form of magnetrons in each row of at least six pieces, which are installed at equal intervals, along the outer sides of the faces there are boxes of the blowing means and transformers, wherein on each side face two boxes of the blowing means are fixed opposite the magnetrons, and the box of the transformers is located closer to the lower edge of the side faces, the moisture removal means is located under the lower face of the chamber, the means for moving lumber is made of a gearbox installed under the lower face of the chamber and interconnected with a trolley located inside on the lower edge of the chamber with the possibility of reciprocating movement, while the control means is made in the form of an electrical panel equipped with a control panel, the chamber is connected to a vacuum pump equipped with a vacuum pressure gauge.

To increase the efficiency of condensate collection, it is advisable to equip the cover plane with two planes connected at an angle, or a part of a cylindrical plane made of polycarbonate.

To simplify the installation of the blower, it is advisable to make it in the form of a fan.

The present invention is explained by a detailed description, an example of implementation and diagrams, in which:

Fig. 1 is a main sectional view of a device for drying lumber according to the invention;

Fig. 2 - right side view, with electrical panel connected to the chamber and vacuum pump equipped with vacuum gauge;

Fig. 3 - photo of a general view of a device for drying lumber, connected to an electrical panel, according to the invention;

Fig. 4 - photo of the electrical panel with the location of the vacuum pump with a vacuum pressure gauge;

Fig. 5 - photo inside the chamber, with a trolley placed in it, capable of reciprocating movement;

Fig. 6 - photo of axonometric view of the device from the left;

Fig. 7 - photo of the arrangement of lumber loaded onto a trolley;

Fig. 8 - photo of the arrangement of lumber along the length of the trolley.

A device for drying lumber (hereinafter referred to as the dryer) comprises a chamber (housing) 1 mounted on supports (not shown) (Fig. 1). The support may be in the form of a frame or four legs located at the corners of chamber 1, or otherwise. Chamber 1 is in the form of a hollow prism having three faces in the form of planes, the fourth face being in the form of a removable cover plane 2. Removable cover 2 is in the form of a face - a plane, along the perimeter of which a connecting element 3 - a board for fastening it with ties (not shown) to chamber 1 is made. Removable cover 2 is secured with the possibility of opening and closing (Figs. 1, 2). A design in the form of two planes connected at an angle (Fig. 2) or in the form of a part of a cylindrical plane made of polycarbonate (not shown) can be installed on removable cover 2.

Chamber 1 contains a lumber handling device capable of reciprocating motion, comprised of a trolley 4 mounted on the inner lower edge of chamber 1 via at least three axles 5, 6, and 7 equipped with pairs of wheels. The lumber handling device is also interconnected with a gearbox 8 mounted externally beneath the lower edge of chamber 1 and interconnected with the trolley capable of reciprocating motion. A tank 9 with a drain for collecting condensate, i.e., water formed (precipitated) from the air on the surfaces of chamber 1 and from the layers of lumber, is located beneath the lower edge of chamber 1.

The microwave energy source is in the form of magnetrons 10-21. Magnetrons 10-21 are mounted in parallel in two rows on each side face (plane) of chamber 1 and secured using fluoroplastic plates.

In this case, magnetrons 10-21 are located in each row in quantities of at least six pieces. Magnetrons 10-21 are installed at equal intervals between each other. On the outer side of each lateral face of chamber 1, opposite each row of magnetrons 10-15 and 16-21, respectively, there are boxes 22, 23 and 24, 25 of blowing means, made in the form of fans. In addition, below the blowing means 24, 25, on each face of chamber 1 there are transformer boxes, respectively, 26 and 27 closer to the lower edge of the lateral faces of chamber 1. In front of the cover 2, on the upper face of chamber 1, there is a fan 28. Chamber 1 is connected by cables to a control means made in the form of an electrical panel 29, and a vacuum pump 30 equipped with a vacuum pressure gauge 31.

The device for drying lumber (hereinafter referred to as the dryer) operates as follows.

In practical terms, specialists refer to a device for drying lumber as a high-speed mini-electric vacuum dryer, or a microwave (ultra-high frequency) device - this is electromagnetic radiation that includes decimeter, centimeter, and millimeter ranges of radio waves.

The device is designed for drying softwood and hardwood lumber. Drying time depends on the wood's density. Oak and larch are considered difficult, while others, such as pine and birch, are easy. A drying mode is selected for each lumber species, ensuring high-quality drying results. No spacers are needed between the boards, so they can be loaded either flat or on edge.

Chamber 1 of the dryer is loaded with lumber of both soft and hard wood species with a maximum capacity of 0.5 ^m3 . The dryer has the following technical characteristics:

1. Power 17 kW.

2. Power consumption in 24-hour mode - 126 kW.

3. Drying time from 20 - 70% humidity to 5 - 7% from 8 to 24 hours.

4. Size of sawn timber 300 - 550 - 3000 mm.

The dryer is housed directly in a six-square-meter workshop, allowing one operator to manually load it in ten minutes (Fig. 3). Drying time ranges from 8 to 24 hours. Magnetrons 10-21 are from the most affordable line, allowing for easy maintenance and vacuum operation.

Vacuum pump 30 with vacuum pressure gauge 31 are placed nearby, at a distance of no more than two meters, on a stand and connected to chamber 1 of the dryer with a rubber hose (Fig. 4). This is convenient for carrying, transporting, installing and operating the dryer itself. The control means in the form of electrical panel 29 (hereinafter panel) is a control panel with start and stop buttons, various protections and a relay. Panel 29 is also located at a distance of no more than two meters and is connected to the structural elements of the dryer: chamber 1, gearbox 8, magnetrons 10-231, blower means - fans 22-25, 28, transformer boxes 26, 27 by cables.

Magnetrons 10-21 are arranged in two rows of six on the side faces of chamber 1 (housing) on both sides (Fig. 5). Magnetrons 10-21 are bolted to the housing using sealant, ensuring proper vacuum operation.

Magnetrons 10-21 are placed on the side walls of chamber (housing) 2 using fluoroplastic plates, which protect the magnetrons from moisture and vacuum. Fluoroplastic meets all requirements: it is heat and moisture resistant, maintains a vacuum well through sealants, and, most importantly, transmits microwaves up to 96%. The fluoroplastic plates are visible in photo 5. They are the 6 mm thick white squares located between magnetrons 10-21 and the side walls of chamber 1.

This arrangement of magnetrons 10-21 covers the area of the entire stack and heats the lumber pointwise, due to the smooth reciprocating movement of the lumber transport means in the form of a trolley 4, which achieves uniform heating of the loaded stack of lumber.

Twelve magnetrons 10-15 on one side and twelve magnetrons 16-21 on the other side are arranged in the side faces of chamber 1, evenly spaced relative to each other. Along the outer surface of the side faces of chamber 1, opposite each row of magnetrons 16-21, corresponding boxes 22, 23 and 24, 25 are installed (Fig. 6). Magnetrons 10-21 are controlled automatically via a time relay located in the general control panel on the electrical panel 29. Control is carried out as follows: magnetrons 10-21 on the sides of chamber 1 operate in turn, namely: if magnetrons 10-15 operate, then magnetrons 16-21 are switched off at this time, i.e. rest, then vice versa. Magnetrons 10-15 and 16-21 on each side of chamber 1 operate in turn for ten minutes, depending on what material is being dried and what drying mode is required.

On the side faces of chamber 1, under the location of boxes with magnetrons 10-21, respectively, boxes of blowing means 22, 23 and 24, 25 in the form of fans 26, 27 are located. Blowing means 28 in the form of a fan is installed on the upper face - cover 2 of chamber 1.

Description of the drying process for edged boards

Freshly cut boards (hereinafter referred to as boards or lumber) were used, even allowing boards of varying thicknesses to be mixed in a single load (Fig. 7). When loading stacks of boards of varying calibers, they were loaded without using spacers between them, as permitted by the proposed technology. Freshly cut boards were loaded into chamber 1 on trolley 4, without exceeding its dimensions (Fig. 8). The lumber was loaded vertically from top to bottom and unloaded in the opposite direction. This loading and unloading process did not take up much space.

After laying the required number of boards (they checked the correctness of laying by turning on the movement of the trolley and, making sure that the lumber did not touch the inner walls (edges) of chamber 1, they stopped the trolley 4 and continued the process of preparation for drying. For this, chamber 1 was covered with a lid 2 and the connecting element - side 3 was tightly pulled through the rubber seal to the edges of chamber 1 with clamping screws. Then they pressed the button and started the vacuum pump 30. The latter then worked in automatic mode. When the readings of the vacuum gauge 31 reached minus 0.5 atmospheres, the operating mode was started. One of the buttons on the panel 29 again turned on a very smooth movement of the trolley 4, in automatic mode. This movement allows for uniform heating of all the lumber (stack), which was placed on the trolley 4. Another button on the panel 29 turned on the magnetrons 10-21. Simultaneously with the switching on of the magnetrons 10-21 included blowing means in the form of fans 22, 23 and 24, 25, transformers 26, 27 for cooling them and fan 28 for blowing chamber 1.

The stack was heated automatically in 10-minute increments, alternating between the heating cycles. Magnetrons 10-15 operated initially, while magnetrons 16-21 cooled. Magnetrons 16-21 then operated, while magnetrons 10-15 cooled. In this mode, magnetrons 10-21 did not overheat. Overheating was also prevented by overheating sensors installed in panel 29. This combination of operation, coupled with the smooth running of trolley 4, prevented the stack of lumber from overheating, thereby ensuring high-quality drying.

Drying time depended on the input moisture content of freshly cut boards (20-50-70%) and the required output moisture content (12-8-5%). Drying times ranged from 8 to 24 hours. Cooling chamber 1 also accelerated the drying process, as condensation formed faster on a cold surface than on a hot one. Fan 28 was used to cool the surface of chamber 1. A low-power refrigeration unit (not shown) can also be used. The resulting condensate flowed neatly down the slopes (shaped as angled planes), cover 2, and then along the walls of chamber 1 to the bottom, condensate collection tank 9, which was inclined toward the drain. Condensate collection tank 9 was emptied after the dryer was turned off, unloaded, and the next batch was loaded. The dryer was switched off automatically using a time relay, set based on the incoming moisture and the dryness requirement of the product made from these boards.

The use of the proposed dryer has shown its advantages:

1. Due to its small dimensions, the dryer can be placed indoors without taking up much space.

2. Rapid heating occurs due to magnetrons 10-21, and uniformity is achieved due to the smooth movement of trolley 4. Thanks to this, the lumber is heated from the inside, which does not lead to defects (cracks, bends, etc.).

3. Due to the cooling of the surface of the housing (chamber) 1 inside, condensate flows down the walls into the container 9, without interfering with the drying process.

4. Chamber 1 is also equipped with a vacuum pump 29, which creates a vacuum and ensures the extraction of hot moisture from the wood, even when magnetrons 10-21 are turned off, which helps cool chamber 1.

5. Camera 1 does not have expensive devices and mechanisms, which allows its maintenance in the easiest and most accessible way.

6. All together makes the device for drying lumber more efficient in drying lumber.

The proposed invention makes it possible to expand the range of small-sized dryers for various types of hard wood, which can be placed in an area of no more than six square meters.

In addition, loading lumber of various types of wood into the chamber can be carried out manually without the use of lifting equipment and machinery.

The proposed invention makes it possible to reduce the drying time of various types of wood.

Claims (3)

1. A device for drying lumber comprising a chamber mounted on a support in which lumber is located, a means for moving lumber, a microwave energy source, a blowing means, a moisture removal means, a control means, characterized in that the chamber is made in the form of a hollow prism having three faces in the form of planes, the fourth face is made in the form of a removable plane-cover equipped with a blowing means, microwave energy sources made in the form of magnetrons are mounted in two rows on the side faces, at least six pieces in each row, which are installed at equal intervals, boxes of the blowing means and transformers are installed along the outer sides of the faces, while on each side face two boxes of the blowing means are fixed opposite the magnetrons, and the box of the transformers is located closer to the lower edge of the side faces, the moisture removal means is located under the lower face of the chamber, the means for moving lumber is made of a gearbox installed under the lower face of the chamber and interconnected with a trolley located inside on the lower edge of the chamber with the possibility of reciprocating movement, while the control means is made in the form of an electrical panel equipped with a control panel, the chamber is connected to a vacuum pump equipped with a vacuum pressure gauge. 2. The device according to paragraph 1, characterized in that the cover plane is equipped with two planes connected at an angle or a part of a cylindrical plane made of polycarbonate. 3. The device according to paragraph 1, characterized in that the blowing means is made in the form of a fan.