Roundwood fuel

Abstract

To be able to provide well-burning log fuel with a necessary minimum ignition property at low cost. 【Solution means】In a log fuel 1A for a stove made of logs 10 cut into a columnar shape of a predetermined length, the log 10 has bark 12 left on the outer peripheral surface as it was at the time of felling, and a cover body 5A is provided in which cardboard 50, 50 is fixed in a state of covering all of the outer peripheral surface of the bark 12.

Description

Technical Field

[0001] The present invention relates to log-shaped firewood used as fuel for combustion equipment such as stoves, and more particularly to firewood logs obtained by cutting raw logs into cylindrical logs of a predetermined length and artificially drying them.

Background Art

[0002] In recent years, from the perspectives of increasing environmental awareness and forest protection, there has been an active movement to utilize thinned wood and surplus wood as fuel. However, the wood obtained from logging operations mainly carried out in summer has a high moisture content and requires a long time to dry. Therefore, if it is used without being sufficiently dried, in addition to the fact that combustion is difficult to proceed due to the presence of a large amount of moisture and the energy efficiency is poor, there is a problem that a large amount of CO2 and smoke are generated during combustion.

[0003] Therefore, for example, in the case of firewood for stoves, although the wood is sometimes put into a drying kiln and artificially dried, in the case of wood with a high moisture content, this drying process requires a long time and consumes extra fuel, leading to an increase in the cost required for the production of firewood fuel. As a result, CO2 is extra emitted while wasting combustion energy in the production process. In addition, about 70% of privately-owned forests in Japan are planted with cedar, pine, and hinoki, but these coniferous trees are not suitable for firewood fuel for stoves because they have poor ignition properties, and it has been difficult to utilize them as thinned wood.

[0004] On the other hand, the firewood logs obtained by cutting raw logs into log shapes of a predetermined length, which have become popular among firewood stove enthusiasts in recent years because of their good ignition properties, have a relatively small area of the cross-sectional part (the cut surface) covered with bark to promote drying on the outer peripheral surface, so they require a relatively long drying time. In addition, since this firewood log has a shape that is difficult to ignite compared to ordinary firewood, it requires an extra combustion process using ignition firewood, an ignition agent, etc. In addition to the poor usability as fuel, it is said that the overall energy efficiency is low.

[0005] Therefore, for example, as described in Japanese Utility Model Registration No. 3213970 and shown in Fig. 5(B), a log fuel 1F is proposed in which cuts are made evenly from the end face of the log so as to form a plurality of cuts (slits) passing through the center of the circle of the end face while leaving the lower part so that they are not separated.

[0006] In this way, by making a plurality of cuts in a direction perpendicular to the cut surface (end face) cut in a log shape to provide a plurality of slits, the total area of the cut surface is enlarged and the drying time is shortened. For example, when cutting to a depth of about three-fourths from the end face and radially dividing into eight equal parts as shown in the figure, when artificially drying to a moisture content of about 20%, drying can be completed in about half the time required for a log without slits of the same size.

[0007] However, since the cross-section by such slits is cut along the conduits in the wood tissue, the function of drying the wood tissue is weaker than that of the end face cut in a direction perpendicular to the conduits. Therefore, in order to dry in a short time, it is necessary to provide a large number of cuts as shown in the figure. In order to radially provide a large number of cuts at the end face, it is necessary to perform a cutting operation while rotating the log around its axis and leave a non-cut part, resulting in excessive labor and cost for the operation.

[0008] Therefore, the inventors / applicants of the present application proposed a log fuel 1E in Japanese Patent Application Laid-Open No. 2015-81332, which is formed by continuously providing slits 90, 90, 90 formed by cutting parallel to the end face from the outer peripheral surface of the log at a depth of two-thirds or more of the diameter at a pitch shorter than the diameter. In this log fuel 1E, moisture is released and dried through the cut surfaces formed by a plurality of slits in addition to the end faces at both ends, so that a shorter drying time can be realized and high energy efficiency can be achieved at low cost.

[0009] However, in a normal wood stove, after sufficiently warming a room with relatively high heat, a good fire that continues to burn for a long time with a smaller amount of heat is also required. In the case of the conventional round logs 1E and 1F described above, although they are excellent in ignition and combustibility due to the presence of slits deeply cut into the logs, they burn up to the center of the log in a relatively short time, so it has to be said that they are insufficient in terms of fire endurance compared to normal round logs. Further, in the above-described conventional examples, there was a problem that the portions partitioned by the deep slits were easily broken during transportation.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0011] The present invention aims to solve the above problems, and an object thereof is to provide a round log for stove fuel having good fire endurance at low cost while having a minimum required ignition property.

Means for Solving the Problems

[0012] Therefore, the present invention provides a round log for stove fuel made of a cylindrical log of a predetermined length, wherein the log has the bark as it was at the time of felling remaining, and a cover body in which cardboard is fixed in a state of covering the entire outer peripheral surface of the bark is provided.

[0013] In this way, by using round logs with bark as round log fuel without providing slits, it becomes fuel for a stove with good combustion persistence. However, by adopting a configuration in which the periphery of the bark is covered with cardboard, due to the drying promotion effect of cardboard that contains a large amount of air and is excellent in moisture absorption and desorption functions, the drying of the round logs can be completed in a relatively short period only by natural drying without using a dryer. Also, when used as stove fuel, since the cardboard can be used as a kindling material, by applying or injecting a liquid fuel onto the cardboard, it becomes excellent in ignitability.

[0014] Moreover, in this round log fuel, if it is characterized in that the cutting length of the round log is in the range of 100 mm to 250 mm, it becomes possible to dry up to the center part of the round log even with natural drying for a relatively short period, while it is easy to ensure good combustion persistence.

[0015] In this case, if the cardboard is characterized in that it has a liner paper only on one side of a corrugated core, and the side where the corrugated core is exposed faces outward and is fixed, due to the corrugated surface shape, the surface area of the outer peripheral surface of the round log fuel becomes significantly larger and it becomes even more excellent in drying property. Furthermore, if the cardboard is fixed in a state where the round log is wound two or more times while the side where the core is exposed faces outward, it becomes even more excellent in drying property and ignitability.

[0016] Furthermore, in the above-mentioned round log fuel, from the upper end side and / or the lower end side of the cardboard located on the end side of the round log, a plurality of perforations are provided in the vertical direction with a predetermined length and are arranged in parallel. By cutting along the perforations from the edge side of the cardboard into a tongue shape with a predetermined width, a flap for ignition is formed on the outer peripheral surface. If it is characterized in this way, the ignition operation becomes even easier. If the base end side of the flap is cut into a strip-shaped cardboard piece, it can also be used as a kindling material to be inserted into the gap on the end side.

Effects of the Invention

[0017] According to the present invention in which the outer peripheral surface of a log with bark is covered with cardboard, even in natural drying, the drying of the log can be completed in a short period due to the drying acceleration effect of the cardboard, and good flammability can also be achieved. Since the cardboard becomes an ignition material during use, it is excellent in ignitability.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[0020] Fig. 1(A) shows a roundwood fuel 1A for a firewood stove according to this embodiment in a perspective view, and Fig. (B) shows the roundwood 10 used for the roundwood fuel 1A. Although it is assumed that thinned wood and surplus wood are used as the roundwood 10, conifers such as cedar, pine, and hinoki, which have not been utilized as firewood fuel for stoves because of their poor burning properties, have become usable firewood fuels with an extended burning time due to the feature of the present invention that they char from the surface and burn slowly. Further, the roundwood 10 is obtained by cutting a felled log with its bark attached into a columnar roundwood having a length of about 100 mm to 250 mm (preferably 150 mm to 200 mm) suitable for a general firewood stove, and it is assumed that the moisture content is reduced to a level suitable for combustion by natural drying before use.

[0021] That is, when using a roundwood 10 with its bark attached having a diameter of about 150 mm to 250 mm in consideration of the burning time, burning energy, and general size of the combustion chamber of the roundwood fuel 1A, experiments have shown that a roundwood length of about 100 mm to 250 mm is necessary to ensure good burning properties while drying in a relatively short period even by natural drying. In particular, it is known that a length of 150 mm to 200 mm is excellent in the balance between the drying time and the burning time. Further, by using the roundwood 10 with its bark attached, there is an advantage that not only can the amount of dust emissions be reduced, but also the burning energy of the bark part can be utilized.

[0022] And in the present invention, as shown in Fig. 1(A), a cover body 5 is provided in which a cardboard 50 is fixed in a state of covering the entire outer peripheral surface of the bark 12 of the roundwood 10, and this point is the most characteristic part in the present invention. In this embodiment, the cardboard 50 is provided in a two-layer structure that covers the outer peripheral surface of the bark 12 of the roundwood 10 in a double layer, but even if it is a single layer, the functions and effects according to the present invention can be fully expected. Further, the two flexible cardboards 50, 50 may be fixed to the bark 12 side with staples or the like to form the cover body 5.

[0023] As described above, by not providing a slit while using the round log 10 with bark, even when using fast-burning coniferous trees, the combustion of the firewood fuel slowly progresses inward while carbonizing from the surface of the log, resulting in a firewood fuel for a stove with good fire retention. However, by covering the periphery of the bark 12 with cardboard 50, the drying time of the log in natural drying can be shortened by 30% to 40% due to the drying promotion effect of the cardboard 50 with excellent moisture absorption and desorption functions. Also, during combustion when used as a stove fuel, it is possible to use it as a kindling material by applying or injecting a liquid fuel onto the paper-made cardboard 50 in the round log firewood that is difficult to ignite.

[0024] Figure 2 shows a cross-sectional partial view enlarged so that the detailed states of the round log firewoods 1B and 1C, which are modified examples of the round log firewood 1A in Fig. 1(A), can be seen. In this example, regarding the configuration of the cardboard 51 that constitutes the cover members 5B and 5C, a material formed by laminating a liner paper only on one side of a corrugated core of paper is used, and it is characterized in that the side where the corrugated core is exposed faces outward and is fixed.

[0025] That is, the round log firewood 1B in Fig. (A) is formed by winding a single strip of cardboard 51 around the bark 12 twice to form two layers, and the round log firewood 1C in Fig. (B) is formed by winding it once to form one layer. In this way, the cardboard 51 with a liner paper laminated only on one side of the core is easy to bend along the continuous direction of the corrugation shape, so it is easy to be arranged in close contact with the outer peripheral surface of the log, and it has the characteristic that even when wound multiple times, they are easy to stack closely with each other.

[0026] Also, due to the corrugated surface shape formed by the cardboard 51, the surface area of the outer peripheral surface of the round log firewood 1B is significantly increased, making it even more excellent in the drying property of the log. In the round log firewood 1B formed by winding and fixing the log two or more times with the cardboard 51, it is even more excellent in drying property and ignitability.

[0027] FIG. 3(A) shows a log fuel 1D as an application example of the above-described log fuels 1A, 1B, and 1C. In the log fuel 1D of this example, a plurality of perforations 52 and 53 are provided in parallel in the vertical direction with a predetermined length from the upper end side and / or the lower end side of the cardboard 51 located on the end side of the cover body 5D on the end side of the log. As shown in FIG. (B), by lifting the end while cutting in a tongue shape with a predetermined width along the perforation from the edge side of the cardboard 51, ignition flaps 55 and 56 are formed on the outer peripheral surface, which is a characteristic feature.

[0028] As a result, the ignition operation of the log fuel 1D becomes even easier. However, as shown in FIG. 4, if the base end side of the flap 56 is cut into a strip-shaped cardboard piece 560, it can also be used as an ignition material while being inserted into the gap on the end side of the log.

[0029] In addition, since a gap is formed between the log body 11 and the bark 12 as the log 10 dries, the cardboard piece 560 may be inserted into the gap to perform the ignition operation. Further, although the above-described log fuels 1A, 1B, 1C, and 1D are assumed to promote ignition by applying or injecting liquid fuel into the above-described gap or the end of the log immediately before ignition, by using the gap between the bark and the log body described above, a solid fuel such as paraffin that melts at a low temperature in advance is poured into a predetermined position thereof and solidified to form an ignition part.

[0030] As described above, regarding the log fuel, with the present invention, while ensuring good fire retention, the log can be dried in a short period at low cost even by natural drying due to the drying promotion effect of the cardboard, and at the time of its use, the cardboard functions as an ignition material, so that it also has excellent ignitability.

Explanation of Reference Numerals

[0031] 1A, 1B, 1C, 1D Log fuels, 5A, 5B, 5C, 5D Cover bodies, 10 Log, 11 Log body, 12 Bark, 50, 51 Cardboard, 52, 53 Perforations, 55, 56 Flaps, 560 Cardboard piece

Claims

1. In a log fuel for a stove made of a cylindrical log of a predetermined length, the log has the bark as it was at the time of felling remaining thereon, and a cover body is provided in a state where cardboard is fixed so as to cover the entire outer peripheral surface of the bark. The log fuel is characterized by this.

2. The cut length of the log is 100 mm to 250 mm. The log fuel according to Claim 1 is characterized by this.

3. The cardboard has a liner paper provided only on one side of a corrugated core, and is fixed in a state where the side where the corrugated core is exposed faces outward. The log fuel according to Claim 2 is characterized by this.

4. The cardboard is fixed in a state where the log is wound two or more times while the side where the core is exposed faces outward. The log fuel according to Claim 3 is characterized by this.

5. From the upper end side and / or the lower end side of the cardboard located on the butt end side of the log, a plurality of perforations are provided in parallel in the vertical direction with a predetermined length, and a flap for ignition is formed on the outer peripheral surface by cutting in a tongue shape with a predetermined width along the perforations from the edge side of the cardboard. The log fuel according to Claim 1, 2, 3 or 4 is characterized by this.

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