JPH0537192Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is applicable to thin plate-like materials that contain a lot of water, such as veneers that are used as materials for plywood products, or thin sheet-like materials such as sheet-like woven fabrics. This invention relates to a material drying device.

[Conventional technology]

In conventional drying equipment, most of the drying equipment is shielded in the form of an airtight container with a heat-retaining plate filled with heat insulating material, etc., except for the inlet and takeout parts of the drying material.
In order to heat the air inside the device, an in-machine air heating device is provided, such as a heat exchanger installed in the in-machine air path or a device that directly feeds high-temperature gas from a combustion burner to the drying device.

On the other hand, a conveyance mechanism is provided to transport the material to be dried into the machine at an appropriate speed, and a fan is also disposed to energize the aforementioned high-temperature air into hot air.
The energized hot air is forced into a hot air blowing duct through a ventilation passage, etc., and the hot air is blown forcefully from the thin grooves of the duct toward the front and back sides of the object to be dried while it is being transported, thereby drying the object. There is.

An example of such a conventional example is "Multi-stage folding dryer" Utility Application No. 49-32280
122370). This idea consists of a veneer transport mechanism (endless transport belt), a burner that heats the air inside the machine and converts it into hot air, and a separate combination of burners for high and low temperatures, as well as a blower for circulating the heated hot air, Using technology adopted in conventional veneer drying equipment, such as ventilation channels and hot air ducts that spray hot air onto the items to be dried, efficient drying is attempted by dividing the veneer into high and low temperature zones using the burner. It is something.

[Problem that the invention attempts to solve]

Conventional drying equipment has undergone various improvements with the aim of increasing drying efficiency, and in that respect it feels like it has almost reached the stage of perfection. However, the device itself occupies a huge amount of space, and the conventional veneer drying device used is a cross-circulation type (a method in which hot air circulates in a direction perpendicular to the direction of conveyance of the material to be dried). ) It is not uncommon for dryers to have a total length of around 30m.

It was difficult to dry the materials uniformly with these conventional drying devices. In particular, the moisture content of veneers obtained from natural wood varies depending on the sapwood, heartwood, etc., so it was extremely difficult to dry them to an average moisture content after the drying process. As a result, it was necessary to select and re-dry the materials that did not reach the specified moisture content after the drying process, which was a wasteful task.

Furthermore, large drying equipment consumes a large amount of thermal energy, and the larger the equipment, the larger the area of heat radiation to the atmosphere, resulting in increased waste in petroleum and other thermal energy consumption.

[Means for solving problems]

This invention uses a conveyor belt on which the article is placed and transported inside the machine, and a conveyor belt on which the article to be dried is placed and transported inside the machine, and the article to be dried placed on the conveyor belt is conveyed while being pressed from above. Use a metal conveyor belt such as a wire mesh on both conveyor belts of the presser conveyor belt, or either one, and coat the conveyor belt with a far-infrared emitting substance that emits far-infrared rays with a wavelength of 2.5 micrometers or more, or It is characterized by being welded.

In this invention, the material to be dried is dried by being exposed to hot air from a hot air blowing duct while being transported by a transport mechanism such as a transport belt. When the far-infrared rays are applied, for example, by coating, the far-infrared rays are effectively emitted from the part and irradiate the front and back of the object to be dried during conveyance.

In general, most organic substances such as polymer compounds and some inorganic substances have a tuning point in a long wavelength range of 2.5 micrometers or more, which means that objects exposed to electromagnetic waves (far infrared rays) in that wavelength range This causes an electromagnetic resonance phenomenon.

Therefore, the material to be dried that is irradiated with far-infrared rays causes an electromagnetic resonance phenomenon and self-heats, rapidly reducing the temperature difference between the surface and the inside, and at the same time homogenizing the internal moisture distribution, resulting in an even, average The drying process will be carried out accordingly.

In other words, as the material to be dried is conveyed through the device, drying is promoted by both the hot air bath and the far-infrared rays bath, which shortens the drying time compared to conventional devices, and as a result, the entire device It is possible to store the product in a compact size, and it also enables efficient drying by circulating hot air at a relatively low temperature, making it possible to prevent problems such as drying distortion caused by high-temperature drying.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings. 1st
The figure is a side view of the entire drying device, and FIG. 2 is a partial side view. Moreover, FIG. 3 is a cross-sectional view seen from the front. In the figure, the drying device 10 has three conveyance paths arranged in the vertical direction for conveying the material to be dried in the direction of arrows A to C, and has a plurality of unit drying sections 11 connected in series, each of which independently heats and circulates hot air. An inlet conveyor 1 is provided at the starting end (left end in FIG. 1) for feeding the material to be dried into the machine in the direction of arrow A.

A cooling section 10C is installed at the end of the plurality of unit drying sections 11 (right end in Fig. 1), which cools the material to be dried whose temperature has risen by receiving hot air to an appropriate temperature, and continues to cool the material to be dried outside the machine. An exit conveyor 23 is provided for taking out the food.

Figure 2 shows 3 parts of the unit drying section for illustrative purposes.
The section is shown with the outer panel partially removed. 14R is a conveyance roller;
Reference numeral 4 denotes a conveyance belt made of a metal net or the like, supported by conveyance rollers, on which the material to be dried is placed and conveyed.

Further, 14K is a holding conveyance belt, which conveys the material to be dried placed on the conveyance belt 14 while pressing it from above to prevent the material from flaring as the material to be dried dries. It is placed on top of the wall facing the wall. In the illustrated embodiment, the above two conveyor belts form a three-stage conveyance path surface in the upper and lower directions, and the material to be dried is conveyed in the directions of arrows A to C by a drive device (not shown).

Note that depending on the object to be dried, the presser conveyor band may be omitted.

FIG. 4 is a plan view of the conveyance belt 14, and shows a conveyance belt made of wire mesh.The presser conveyance belt 14K is also often made of wire mesh, and a mesh size smaller than that of the conveyance belt 14 is usually adopted. In the present invention, for example, a powdery far-infrared radiation material 6 is applied to the side of both conveyance belts facing the material to be dried, or the entire outer peripheral surface of the conveyance belt, or powdered or other far-infrared radiation material 6 is applied. It welds the radiation.

For coating, powdered far-infrared rays are appropriately mixed into the paint and applied, and for welding, plasma spraying on a metal conveyor belt, and other methods are used.

The far infrared rays 6 are made of zirconia, for example.
Ceramics fired mainly from alumina, titania, etc., manganese dioxide, chromium oxide,
Ceramics or the like fired using transition element oxides such as iron oxide or cobalt oxide as main raw materials are used in powder form as needed. In any case, the wavelength
Those that have the characteristic of emitting a large amount of far-infrared rays of 2.5 micrometers or more are used.

13 is a fan, which is rotationally driven by the electric motor 12, and the cabin air energized by the fan descends in the direction of arrow O through the ventilation passage 15 arranged on the right side of FIG. The hot air flows to ducts 16 arranged in stages for blowing out hot air.

The hot air (whose temperature has been raised by a heating device 18, which will be described later) that is forced into the hot cold blowing duct is vigorously blown out from slits opened at the top and bottom of the duct, and is then passed through the conveyor belt 14 and 14K. At this time, the material to be dried is heated, but at that time, the conveyor belt is naturally heated, and the temperature of the far-infrared radiation material coated or welded is also increased, effectively increasing the temperature of the far-infrared radiation material with a wavelength of 2.5 micrometers or more. It will emit infrared rays.

Therefore, the material to be dried sandwiched between both conveyor belts is irradiated with hot air and a large amount of far-infrared rays from the front and back as it is transported through the machine, causing self-heating due to the electromagnetic resonance phenomenon, resulting in extremely effective drying work. It will be done.

The hot air ejected from the hot air injection duct rubs the material to be dried, dries it, lowers its temperature, passes through the ventilation passage 17 in FIG. 3, rises in the direction of arrow Q, and is sucked into the fan 13. It moves from arrow R to direction S.

18 is a heating device; in the illustrated embodiment, a fin heater that introduces a heat source such as steam through a stop valve 33 is used;
The low-temperature hot air sucked in by 3 passes through the heating device 18 from arrow R to S, where it is reheated and becomes high-temperature hot air, and then continues down the ventilation passage 15 in the direction of arrow O, and then passes through the hot air blowing duct. Then, the drying operation is continued while repeating the hot air path circulation described above.

The heating device includes a heat exchanger such as a fin heater, as well as a combustion burner attached to the side wall of the drying device.
There is also a method of directly feeding combustion gas into the cabin.

Reference numeral 19 denotes an exhaust pipe for discharging humid air generated as the drying progresses to the outside of the machine.

With the above configuration, the cabin air energized by the fan 13 is heated by passing through the heating device 18 while repeating circulation in the direction of the arrow OPQRS. The dried products are transported one after another and are successively dried by being exposed to these hot air.

Furthermore, far-infrared rays with a wavelength of 2.5 micrometers or more are emitted from the conveyor belt that holds and transports the dried material, and the dried material is irradiated with far-infrared rays from both sides, causing an electromagnetic resonance phenomenon.
This causes self-heating, further accelerating drying.

As described above, in this invention, the material to be dried is irradiated with far infrared rays to induce self-heating of the material to be dried, and then the hot air is superimposed and blown on both sides to dry the material, so there is no need to raise the hot air temperature much higher than in conventional drying methods. It is.

Furthermore, the electromagnetic resonance phenomenon caused by far infrared rays has the effect of eliminating the temperature difference between the surface and the inside of the object to be dried, resulting in a uniform moisture distribution, making it difficult to dry evenly, such as with veneers obtained from natural wood. It is possible to achieve even drying even with the most durable materials.

In this embodiment, both the conveyance belt 14 and the presser conveyance belt 14K are described in detail as an example of a wire mesh conveyance belt, but examples in which the conveyance belt is a chain, a track pillar, a perforated steel belt, etc. It is also possible to use a coil spring wire formed by tightly winding a wire into a spring shape, or to arrange the above-mentioned conveyance belts in various combinations in the front and back or the top and bottom.

Furthermore, with regard to coating or welding of the far-infrared rays to each conveyance belt, in addition to applying it to both the conveyance belt 14 and the presser conveyance belt 14K, it may be applied only to the conveyance belt on either side of the upper or lower arrangement. Alternatively, various combinations may be adopted, such as dividing the drying device into a front and a second half, applying far-infrared radiation to both the upper and lower conveyor belts in the first half, and applying far-infrared radiation only to the lower conveyor belt in the latter half.

Furthermore, in this embodiment, the hot air circulation direction is perpendicular to the direction of transport of the material to be dried, so-called cross-circulation type drying apparatus has been described. Even in the hot air vertical circulation method parallel to the conveying direction,
A similar effect can be achieved by using a conveyance belt to convey the material to be dried within the machine and by coating or welding a far-infrared emitting material onto the conveyance belt.

Also, depending on the type of material to be dried, a method may be used in which the presser conveyor belt is omitted and the material to be dried is simply placed on the conveyor belt and dried while being transported.In this case, far infrared rays are irradiated from below. Although it depends on the product, it can be effective in drying relatively thin woven fabrics.

[Effect of idea]

According to the present invention described above, the following effects can be obtained.

(1) Self-heating due to electromagnetic resonance phenomenon increases drying efficiency, making it possible to save energy and space.

(2) It is possible to dry at a lower temperature than conventional drying, and as a result, it is possible to prevent the occurrence of cracks due to rapid drying shrinkage and the quality deterioration of the dried material due to drying distortion.

(3) Low-temperature drying makes it possible to reduce drying shrinkage and is expected to improve yield.

(4) When drying veneers, which are the raw material for plywood products, the difference in moisture content between the core and sapwood parts causes uneven drying of the finished moisture content, making it necessary to re-dry some parts. However, according to the present invention, by uniformizing the moisture distribution of the material to be dried by far-infrared irradiation, it is possible to achieve an even drying finish, and wasteful work such as re-drying can be omitted.

[Brief explanation of drawings]

The drawings schematically show one embodiment of the present invention, and FIG. 1 is a side view of the entire drying device, FIG. 2 is a partial side view, FIG. 3 is a sectional view seen from the front, and FIG. The figure is a plan view of the conveyor belt. 1...Entrance conveyor, 6...Far-infrared radiation,
10... Drying device, 11... Unit drying section, 14... Conveyance belt, 14K... Presser conveyance belt, 1
5, 17...Ventilation path, 23...Exit conveyor.

Claims (1)

[Claims for Utility Model Registration] 1. A drying device that dries objects to be dried while conveying them, comprising a heating device that heats the air inside the machine, a fan that circulates the heated air inside the machine, and a place on which the objects to be dried are placed. and a presser conveyor belt that presses and conveys the material to be dried while being conveyed from above. A drying device characterized by coating or welding far-infrared radiation. 2. The far-infrared rays that are coated or welded to the conveyor belt and/or presser conveyor belt are characterized by emitting far-infrared rays with a wavelength of 2.5 micrometers or more. Drying equipment as described. 3. The drying device according to claim 1 or 2, wherein the conveyance belt and/or the presser conveyance belt are constructed of a metal net. 4. The drying device according to claim 1 or 2, wherein the conveyance belt and/or the presser conveyance belt are constituted by a chain. 5. The drying device according to claim 1 or 2, wherein the conveyance belt and/or the presser conveyance belt are constituted by caterpillars. 6. The drying device according to claim 1 or 2, wherein the conveyance belt and/or the presser conveyance belt are constructed of coil spring wire. 7. The scope of the utility model registration claim characterized in that the hot air circulating inside the machine is circulated perpendicularly to the conveying direction of the dried material while rubbing the dried material transported in the drying device, Paragraphs 1 to 7 The drying device according to any one of Item 6.