JPH0467900A - Method and device for drying plate shape fiber material - Google Patents

Abstract

PURPOSE:To dry a material to be dried continuously with high efficiency and to improve the quality of a product after drying by drying the material by far infrared radiation, and drying by performing dielectric heating by a microwave. CONSTITUTION:The material 5 to be dried such as a bedding, etc., is carried from an upstream side to a downstream side, and a far infrared radiation drying area 6 is formed at the upstream side of a carrier path 3, and a microwave drying area 7 is formed at the downstream side than the far infrared radiation area 6. A carrier means 2 is formed by stretching a conveyer belt 8 by guiding of guide rollers 9, 10 and 11, 12. The conveyer belt 8 is stretched horizontally between the rollers 9, 10, and the material 5 to be dried is loaded on an upper stretching part 8a from an entry 13, and the material 5 to be dried after drying is ejected from an exit 14. The upper part of the exit 14 is covered in such a way that it can be opened and closed with a cover 15 supported so as to displace an angle around a horizontal axis. The bedding that is the material 5 to be dried is whole-washed with water, and the percentage of water content of the material 5 to be dried sent from the entry 13 can be set at around 50%, assuming that the percentage of water content in whole washing is set as 100% by performing a centrifugal dehydration or decompression suction operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for drying tabular fibrous materials such as futons and the like.

A conventional futon has a structure in which a filling layer of a flat fiber material such as cotton or linen is covered with a cloth such as cotton or linen. To wash this futon, first wash the futon with water, then spin it out.If the moisture content at the time of washing is 100%, after spin-drying it will be about 50%, and then dry it. The conventional drying method for flat fiber materials with high water content, such as futons, involves heating air to an appropriate temperature, bringing the heated air into contact with the material to be dried, which is the futon, and raising the temperature of the material to be dried. A method is used in which the moisture contained in the heated air is diffused onto the surface of the object to be dried, the moisture is evaporated by the heat of the same heated air, and the evaporated moisture is discharged to the outside together with the exhaust air.

Problems to be Solved by the Invention However, in this conventional method, the temperature is increased by heating from the surface of the flat fiber material, and the transfer of heat from the surface of the flat fiber material to the inside is limited to the structure of the flat fiber material. The amount of heat determined by the physical properties and thermal conductivity characteristics is limited, and since fiber materials generally have low thermal conductivity, the temperature rises slowly in the center, making it difficult to promote water evaporation. Therefore, with conventional drying methods, it is not possible to increase the amount of water evaporated per unit time, and as a result, the drying time is extremely long, making continuous operation difficult and requiring excessive labor for batch operation. be. A particularly big drawback is that the evaporation rate of water vapor, which occurs in proportion to the rate of heat transfer from the back surface of the fiber material to the center layer, is slow, resulting in poor texture and poor quality of the product. That's true.

An object of the present invention is to provide a method and apparatus for drying a flat fiber material, which can continuously and efficiently dry a material to be dried, and can improve the quality of the product after drying. It is.

Means for Solving the Problems The present invention is a method for drying a flat fibrous material, which is characterized in that the fibrous material is dried using far infrared rays, and then dielectrically heated using microwaves for drying.

The present invention also provides a drying device main body, a transport means for transporting the material to be dried into the main body, and a gas burner provided in the middle of the transport path of the transport means and radiating far infrared rays to form a far infrared drying region. and a microwave generating means which is provided on the downstream side of the gas burner in the conveying path of the conveying means and which radiates microwaves to form a microwave drying area, and a far infrared drying area and a microwave drying area on each downstream side. This drying apparatus for flat fiber material is characterized in that it includes hot air supply means for supplying hot air from each upstream side and discharging hot air from each upstream side.

Function According to the present invention, an object to be dried such as a futon is first dried by far infrared rays so that the moisture content is reduced to a predetermined amount, and then heated by microwaves. As a result, drying is performed continuously until the moisture content of the dried material reaches a predetermined target value. In other words, far infrared rays are used to actively dry the area near the surface of the material to be dried, thereby reducing the moisture content of the layer near the surface of the flat II fiber material. Therefore, radiation of far infrared rays causes a large gradient in the moisture content of the material to be dried in the thickness direction. By radiating microwaves to the object to be dried in this state, the object to be dried is dielectrically heated. This microwave has the property of being easily absorbed by water during boat fishing. As mentioned above, the layer near the surface of the material to be dried is
Since it has been pre-dried to a low moisture content by far infrared rays, the microwave energy can easily reach the center layer of the material to be dried, and therefore selectively heats the center layer. The water vapor and water droplets from the debris pass through the layer near the surface, which has a low moisture content, and are radiated to the outside. In this way, not only the layer near the surface of the object to be dried but also the center layer is sufficiently dried to prevent uniform drying from occurring.

Moreover, according to the present invention, since the post-drying process is performed by dielectric heating using microwaves, the material to be dried swells and a product with an extremely good texture is obtained, which is especially convenient for drying futons. be.

Furthermore, according to the present invention, hot air supply means is provided in the far-infrared drying area and the microwave drying area, and the hot air is guided from the downstream side to the upstream side of the conveyance path. Therefore, water vapor and water droplets released from the material to be dried are discharged from the main body of the drying apparatus by this hot air, that is, to the outside of the system. Moreover, since this hot air is supplied from the downstream side to the upstream side of the conveyance path as described above, water vapor and water droplets are guided by the hot air to the upstream side of the conveyance path where there are many water vapor and water droplets. Advantageously, this hot air lowers the moisture content downstream of the conveying path in each drying zone.

In the explanation of the above-mentioned operation, the explanation has been made assuming that the material to be dried contains water, but the present invention can be carried out in the same manner even when a liquid other than water is contained in the material to be dried.

Example FIG. 1 is a sectional view of one embodiment of the present invention.

In the drying device main body 1, an object to be dried 5 such as a futon is conveyed from upstream to downstream in the direction of an arrow 4 along a conveying path 3 of a conveying means 2. A far-infrared drying region 6 is formed, and a microwave drying region 7 is formed downstream of this far-infrared drying region 6. The conveyance means 2 includes an endless conveyor belt 8 and a guide roller 9.
, 10 and 11.12.

The conveyor belt 8 is stretched horizontally between the rollers 9 and 10, and the material to be dried 5 is placed on this stretched portion 8a from the inlet 13, and the material to be dried 5 after being dried is carried from the outlet 14. be discharged. The outlet 14 is openably and closably closed by a lid 15 whose upper portion is supported so as to be angularly displaceable around a horizontal axis.

As shown in FIG. 2, the conveyor belt 8 has a mesh-like plane, which facilitates the dissipation of water vapor and water droplets caused by heating.

The conveyor belt 8 is made of a material that does not easily absorb microwaves and has strong thermal or mechanical characteristics, such as a special glass cloth coated with Teflon.

The futon, which is the item to be dried 5, is washed with water, and then
When the moisture content during washing is set to 100% by centrifugal dehydration or vacuum suction operation, the moisture content of the dried material 5 fed through the inlet 13 is approximately 50%. This conveyor belt 8 is driven and run so that its overstretched portion 8a is in the conveyance direction 4.

In the far-infrared drying area 6, flat gas burners 16 and 17 that emit far-infrared rays are provided above and below the overstretched portion 8a of the conveyor belt 8.

The wavelength of the far infrared rays emitted from these gas burners 16 and 17 is, for example, 4 to 1000 μm.

The microwave drying area 7 is separated from the far-infrared drying area 6 by a partition plate 18, and the partition plate 18 has an extension 19 extending along the microwave drying area 7, so that each area 6. 7, the gas flow between them is made to be as small as possible.

Microwaves are emitted from the microwave generation source 22 to the upper part 22 of the microwave drying area 7 via the waveguide 21 .

The frequency of this microwave is, for example, 2450 MHz. This opening 20 is covered with a shielding member 23 to prevent gas from entering the microwave drying area 7. This shielding member 23 is made of a material with low microwave loss and strong thermal characteristics, for example,
Made of polyimide resin, etc.

The partition plate 18 functions to minimize the amount of microwaves radiated to the microwave drying area 7 leaking into the far-infrared drying area 6.

This extension 19 of the partition member 18 serves to minimize leakage of microwaves. The aforementioned inlet 13 is also formed with an elongated extension 25 extending along the overhang portion 8a of the conveyor belt 8, thereby preventing microwaves and gas from leaking to the outside. Drying device main body 1, partition 18 and extension part 19.2
5 and even i15 etc. are made of a conductive material, such as metal, which is grounded to prevent microwave leakage.

Rollers 10.11 of the conveying means 2 in the drying device main body 1
In between, the conveyor belt 8 is moved along the extension 26, which also prevents leakage of gases etc. and also prevents leakage of microwaves. The material to be dried 5 conveyed by the overstretched part 8 of the conveyor belt 8 of the conveying means 2 is delivered to the outlet 14 by a roller conveyor 27 arranged downstream of the microwave drying area 7 (left side in FIG. 1). It will be transported further towards the destination.

In the far-infrared drying area 6, a hot air injection nozzle 28.29 is provided between the overstretched portion 8a of the conveyor belt 8 and the gas burners 16, 17.
In this case, relatively high temperature gas from the heat source 30 is transferred to the heat exchanger 3.
The temperature is further increased by 1, for example, 98℃
The hot air having this temperature is supplied from the pipe line 33 to the nozzle 28, 29 via a flow rate control valve 32P such as a damper. Similarly, the hot air from the heat exchanger 31 is supplied to the nozzles 36 and 37 of the microwave drying area 7 through a flow rate control valve 34 such as a damper. Nozzle 36.3
7 are respectively arranged above and below with respect to the upper rack part 8a of the conveyor belt 8 in the microwave drying area 7, and are arranged on the downstream side of the conveyance path.

Pipe lines 38 and 39 are provided upstream of the far-infrared drying area 6 and the microwave drying area 7 in the conveying direction 4, respectively, and the gas in each area 6.7 is drawn by an exhaust fan 40.41 to the atmosphere. Dissipated.

FIG. 3 (1) is a cross-sectional view of a part of the futon, which is the object 5 to be dried. A flat fiber material 42 such as cotton or linen is covered with a cloth 43 made of the same material. The moisture content of the dried material 5 fed through the inlet 13 after being completely washed and dehydrated is approximately 50%, as shown by reference numeral 11 in FIG. 3(2), and the moisture content in the thickness direction (
1 and 3 (in the vertical direction (1)).

When such a material to be dried is transported from the inlet 13 to the far-infrared drying area 6 by the transport means 2, the gas burner 16,
The layers 44 and 45 near the upper and lower surfaces of the futon 5 are rapidly heated and dehumidified by the radiation of the far infrared rays 17. At this time, a relatively large amount of moisture remains in the center portion 46. In this way, after the material to be dried 5 passes through the far-infrared drying region 6, as shown by reference numeral 12 in FIG. It has a gradient of rate.

Steam and moisture evaporated from the material to be dried 5 in the far-infrared drying area 6 are moved by hot air from the nozzles 28 and 29 from the downstream side to the upstream side of the conveyance path 3 (from the left to the right in FIG. 1). and is drawn from conduit 38 by exhaust fan 40. Therefore, the humidity of the gas is low on the downstream side of the conveyance path 3 of the far-infrared drying area 6, that is, near the nozzles 28 and 29, and therefore the moisture content of the material to be dried 5 conveyed to the subsequent microwave drying area 7 is compared. can do.

In the microwave drying region 7, since the moisture content of the layers 44, 45 near the surface of the object to be dried 5 is low, the microwaves reach the central layer 46 without being absorbed by water. As a result, water in the center layer 46 having a high water content is heated and evaporated. Water vapor and water droplets from the central layer 46 smoothly pass through the layer 4445 near the surface and are discharged into the space within the microwave drying region 7. The hot air from the nozzles 36 and 37 guides the water vapor and water droplets from the material to be dried 5 to the upstream side of the conveyance path 3, and from the pipe 39 to the exhaust fan 41.
is attracted and excreted. In this way, it is possible to remove moisture near the center layer 46 of the object to be dried 5 and dry it using microwaves. At the upstream position where the nozzles 36 and 37 of the microwave drying area 7 are provided, the humidity in the gas is low, and therefore the moisture content of the dried material 5 after drying can be sufficiently reduced. In the material to be dried 5 transported to the microwave drying area 7, the center layer 46 has a higher moisture content than the layers 44 and 45 near the surface, so the penetration power of microwaves into the material to be dried increases. As a result, the center layer 46 of the material to be dried 5 is selectively heated, the drying effect is improved, and finally the material to be dried 5 can be dried uniformly in the thickness direction. In addition, a far infrared drying area 6 using gas burners 16 and 17
Since drying can be carried out while the object to be dried 5 is conveyed by the conveying means 2 having the conveyor belt 8 in the microwave drying area 7 using the microwave that follows it, a continuous drying operation can be achieved. be able to. The material to be dried 5 whose moisture content has been reduced to the target value in this way is
1215 is opened, the sheets are instantly transported one by one to the outside of the drying apparatus main body 1 by the roller conveyor 27. When the lid 15 is opened and the dried material 5 is discharged from the main body 1, the microwave generation source 22 temporarily stops oscillating, thereby ensuring safety against microwave leakage.

In this way, heating drying using microwaves is used as a post-drying process using far infrared rays, so that the moisture remaining in the material to be dried 5 is directed toward the layers 44 and 45 near the surface in the microwave drying area 7. It dries through a process of rapid evaporation. Therefore, the material 42 of the dried material 5 is finished in a swollen shape as a whole, and a product with an extremely good texture can be obtained.

If you try to dry the material to be dried 5 which has a high water content using only microwaves, the material to be dried which is in a state of high moisture content will be directly irradiated with microwaves due to the high absorption property of microwaves for moisture. There is a problem in that only the surface portion of No. 5 is heated strongly, resulting in non-uniform drying in the thickness direction. Additionally, if microwaves alone were to provide the energy needed for drying, the equipment would be expensive.
There are also problems from an economic standpoint.

Therefore, in the above-described embodiment of the present invention, the object 5 to be dried, which is a futon whose moisture content has become, for example, about 30% by centrifugal dehydration or vacuum suction operation, is first treated with far infrared rays on both the upper and lower sides of the object 5 to be dried. The layers 44 and 45 near the surface are actively dried, and the moisture contained in the layer 44 and the center layer 46 is rapidly dried between the layers 44 and 45 and the center layer 46.
By radiating microwaves to the object 5 to be dried after forming the object 5, the microwave energy can easily reach the center layer 46 of the object 5 to be dried, and only the center layer 46 is selectively irradiated. This allows for efficient and uniform drying in the thickness direction.

Furthermore, by combining the heating processes of far infrared rays and microwaves, it becomes cheaper and has greater economical advantages than equipment that uses only microwaves. It is also possible to combine the individual wave drying steps to make the drying operation continuous.

Furthermore, in the present invention, since microwaves are used as a post-drying process using far-infrared rays, the futon, which is the object to be dried 5, swells up as a whole, resulting in a product with an extremely good texture.

The present invention can be applied not only to drying objects such as futons, but also to a wide range of other uses.

Effects of the Invention As described above, according to the present invention, items to be dried such as futons are dried with far infrared rays and then dielectrically heated with microwaves, so that the items to be dried can be dried continuously and efficiently. It becomes possible to remove liquids such as moisture and sufficiently dry the central layer.

Furthermore, since dielectric heating using microwaves is performed after drying using far infrared rays, the flat fiber material to be dried swells, resulting in a product with an extremely good texture.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a plan view of a conveyor belt 8, and FIG. 3 is a diagram for explaining the operation when drying an object 5 to be dried. DESCRIPTION OF SYMBOLS 1... Drying apparatus main body, 2... Conveying means, 3... Conveying path, 4... Conveying direction, 5... Material to be dried, 6...
・Far-infrared drying area, 7...Microwave drying area, 8
... Conveyor belt, 13... Inlet, 14... Outlet, 16... Far infrared gas burner, 22. Microwave source, 28° 29; 36, 37... Nozzle, 30...
Heat source, 31 Heat exchanger, 40, 41...Exhaust fan, 44
．． 45・Layer near the surface, 46...Central layer agent Patent attorney Keiichi Saikyo

Claims (2)

[Claims] (1) A method for drying a flat fiber material, which comprises drying the flat fiber material using far infrared rays, and then dielectrically heating the fiber material using microwaves. (2) A drying device main body, a transport means for transporting the material to be dried into the main body, a gas burner provided in the middle of the transport path of the transport means and radiating far-infrared rays to form a far-infrared drying region; A microwave generating means is provided on the downstream side of the gas burner in the conveyance path of the means and radiates microwaves to form a microwave drying area, and a microwave generating means is provided downstream of a far-infrared ray drying area and a microwave drying area. 1. An apparatus for drying a flat fiber material, comprising hot air supply means for respectively supplying hot air and discharging hot air from each upstream side.