JP2007232241A - Wood pellet fuel combustion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wood pellet fuel combustion device capable of properly burning wood pellet while preventing adhesion of ash and soot scattering in a space of a combustion chamber to an inner side of heat-resisting glass of an inspection window, preventing adhesion of tar to an inner surface of the heat-resisting glass by circulating and spraying a part of the combustion wind of high temperature as it is, as the wind sprayed to the inner surface of the heat-resisting glass, preventing lowering of a temperature of the combustion chamber, and further controlling the generation of tar. <P>SOLUTION: This wood pellet fuel combustion device comprises the transparent or translucent heat-resisting glass disposed at least at a front side of the combustion portion, and a blowing-out portion for supplying the air toward an inner surface faced into the combustion portion, of the heat-resisting glass, and further comprises a circulating passage communicating a discharge portion and a blowing-out portion of the combustion wind. A part of the combustion wind discharged from the discharge portion of the combustion wind is supplied to the circulating passage, and the supplied combustion wind is blown out from the blowing-out portion toward the inner surface of the heat-resisting glass. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wood pellet fuel combustion apparatus for preventing adhesion of ash, soot and the like to heat-resistant glass such as a heater using wood pellets as combustion fuel.

  Conventionally, fossil fuel coal and oil, which have been used as fuels for heating and the like, have been converted to natural friendly resources instead of natural warming due to greenhouse gases such as carbon dioxide.

  Of the expected resources, biomass fuel, which is considered to be effective due to environmental problems, is attracting attention as fuel for rice husk or its pellets, firewood, etc., especially thinned wood, large sawdust, driftwood, etc. The wood material which has been used is granulated as wood pellets and used as a combustion fuel for a heater or the like, and its apparatus becomes known as a solid fuel stove described in Japanese Utility Model Publication No. 58-190301 (Patent Document 1). Yes.

  Among the wood pellet fuel combustion devices, the wood pellet stove has an effect of giving a peace of mind by producing a flame during combustion in addition to the effective use of the biomass fuel, and Japanese Patent Application Laid-Open No. 2004-293930 (Patent Publication 2). A wood pellet stove equipped with a transparent plate that can confirm the flame burning in the combustion chamber from the outside is also known.

  By the way, the amount of ash generated after burning the wood pellets, for example, the wood pellets formed in the wood part of the wood has an ash content of about 0.5 to 2.0%, but the pellets molded with bark In ash, the amount of ash increases to about 5 to 7%, and the amount of ash varies depending on the wood to be pelletized. Of course, the ash deposited after burning the wood pellets with a large amount of ash and the combustion wind The amount of ash that soars also increases.

  In addition, the ignitability of wood pellets varies depending on the quality of the wood, and the ignitability of the pellets formed from bark is worse than the pellets formed from the xylem. There is a tendency not to ignite easily.

  Even in the combustion of wood pellets formed by the wood part of the wood, soot is likely to be generated along with the ash that rises somewhat with the combustion wind, especially in the case of incomplete combustion, ignition, etc. When it adheres to the inner surface of the heat-resistant glass viewing window that is provided so that the flame can be seen, especially when the aforementioned bark pellets are burnt, the observation window is fogged, especially due to ignitability, and the stove is controlled A person frequently needs to clean the sight glass.

  Therefore, as disclosed in Japanese Patent Application Laid-Open No. 2004-191017 (Patent Document 3), a blowing unit that blows air toward the inner surface of the heat-resistant glass serving as a viewing window, an air supply unit that takes in outside air, and air that connects the two. A passage is provided so that a part of the combustion air taken in from the air supply part is guided to the air passage, and the air is blown from the blowing part toward the inside of the heat-resistant glass to be applied to the inner surface of the heat-resistant glass. Also known is an invention that prevents adhesion of ash and soot, promotes prevention of dirt on the heat-resistant glass, and eliminates periodic cleaning of the glass surface.

Japanese Utility Model Publication No. 58-190301 JP 2004-293930 A JP 2004-191017 A

  When wood pellets are burned, tar is generated in addition to the ash and soot, and tar generation increases when the combustion temperature is about 150 ° C. or lower. In particular, when the aforementioned bark pellets are burned, the amount of tar generated increases due to the problem of ignitability.

  Although it is possible to prevent soot and ash from adhering to the inner surface of the heat-resistant glass by spraying a part of the outside air from the air supply part on the inside of the heat-resistant glass in Patent Document 3, it is directed toward the heat-resistant glass. Since the outside air is blown, the temperature in the vicinity of the heat-resistant glass is low, and it can be said that tar is likely to be generated.

  Even if outside air is blown toward the heat-resistant glass, some of the combustion wind that spirals in the combustion chamber may pass near the inner surface of the heat-resistant glass, and the combustion air is mixed with the outside air. There is a situation in which tar is generated due to low temperature, and it adheres to the heat-resistant glass and becomes cloudy.

  In addition, since the outside air is taken into the combustion chamber, it prevents the temperature of the combustion chamber from rising, such as when the outside air is extremely low, and prevents good combustion of the wood pellets by promoting the tar generation environment and lowering the temperature of the combustion section. Is.

  Therefore, in the present invention, the effect of preventing ash and soot scattered in the space in the combustion chamber from adhering to the inner surface of the heat-resistant glass of the viewing window, and the wind blown on the inner surface of the heat-resistant glass, A wood pellet fuel combustion system that can prevent and prevent tar from adhering to the inner surface of the heat-resistant glass and prevent the temperature of the combustion chamber from decreasing and perform good wood pellet combustion by circulating and spraying as it is. The purpose is to provide.

  In addition, part of the combustion air blown on the inner surface of the heat-resistant glass passes through the dust collector, so that ash scattering in the combustion chamber is suppressed and the circulating combustion air is heated in the combustion section to increase the temperature. By spraying on the inner surface of the heat-resistant glass while maintaining it, the object is to prevent further tar adhesion and prevent the temperature of the combustion part from decreasing.

  In order to achieve the above object, the present invention proposes a wood pellet fuel combustion apparatus according to claims 1 to 3.

  That is, the wood pellet fuel combustion apparatus according to claim 1 is a combustion tank that stores wood pellets, a combustion section having an ignition device, a fuel supply apparatus that supplies wood pellets from the fuel tank to the combustion section, and a combustion section. A wood pellet fuel combustion apparatus comprising an air passage for supplying air and a combustion wind exhaust for discharging combustion wind burned in the combustion section, wherein the apparatus is a transparent or translucent disposed at least on the front side of the combustion section A heat-resistant glass and a blowout portion that supplies air toward the inner surface facing the combustion portion of the heat-resistant glass, a circulation passage that communicates the exhaust portion of the combustion wind and the blowout portion, and from the exhaust portion of the combustion wind A part of the exhausted combustion wind is supplied to the circulation passage, and the supplied combustion wind is blown out from the blowing portion toward the inner surface of the heat-resistant glass.

  The wood pellet fuel combustion apparatus according to claim 2 is the wood pellet fuel combustion apparatus according to claim 1, wherein the exhaust portion of the combustion wind includes a dust collector, and the combustion wind passes through the dust collector of the exhaust portion, It is characterized by being configured to blow out to the heat-resistant glass from the blowing part.

  The wood pellet fuel combustion apparatus according to claim 3 is the wood pellet fuel combustion apparatus according to claim 1 or 2, wherein a part of the circulation passage that communicates the exhaust portion and the blowout portion of the combustion wind is wood in the combustion portion. The pellets are arranged in contact with a combustion dish in which the pellets burn.

  The soot and ash generated by burning wood pellets is prevented from adhering to the inner surface of the heat-resistant glass that serves as a viewing window in the combustion chamber. Since it is sprayed in a circulating manner, its temperature is high and has the effect of preventing tar adhesion. Furthermore, since a part of the circulated combustion wind is configured to pass through the dust collector, the ash scattering is reduced, and the circulated combustion wind is configured to pass near the combustion dish of the combustion unit. Therefore, it increases the spraying temperature and has the effect of suppressing the generation of tar adhering to the inner surface of the heat-resistant glass.

  In addition to preventing the temperature of the combustion chamber from lowering by circulating the combustion air and suppressing the tar generation environment, it is possible to perform good combustion of the wood pellets by keeping the combustion chamber temperature at a high temperature. Is.

  As an example of the wood pellet fuel combustion apparatus of the present invention, a pellet stove using wood pellets as fuel will be described below.

  FIG. 1 is a schematic side sectional view showing a pellet stove as a basic structure of the present invention. FIG. 2 is a schematic side sectional view of a wood pellet stove illustrating a wood pellet fuel combustion apparatus according to the first embodiment of the present invention. FIG. 3 is a schematic side sectional view of a wood pellet stove illustrating a wood pellet fuel combustion apparatus according to a second embodiment of the present invention. FIG. 4 is a perspective view showing a blowout portion and a combustion portion of the embodiment of FIG. FIG. 5 is a plan view showing the blowout part and the combustion part (combustion dish) of FIG. 4. 6 is a plan view showing another example of FIG.

  In FIG. 1, 1 is a wood pellet stove. “a” is a wood pellet, and in the pellet stove 1, a combustion chamber 2 in which the wood pellet a burns, and a heat exchanging portion 5 are provided from the middle to the top. A combustion wind exhaust port 7 is provided at the upper end of the combustion chamber 2 to circulate the combustion wind to the exhaust section 6. A fuel tank 3 is provided adjacent to the combustion chamber 2, and a fuel supply device 4 for supplying the wood pellets a from the fuel tank 3 to the combustion chamber 2 is provided in close contact with the fuel tank 3. Reference numeral 38 denotes an air passage, which is an opening for taking outside air into the wood pellet stove 1, and the outside air sucked from the air passage 38 is used as hot air and combustion air for cooling and ignition of each portion. The fuel tank 3 shown in FIG. 1 has a space up to the upper end of the pellet stove 1, and the upper surface of the pellet stove 1 serves as a door so that the wood pellet a can be put into the fuel tank 3 (see FIG. 1). Not shown).

  The bottom plate 10 constituting the lower end of the fuel tank 3 is inclined toward the fuel supply device 4 so that the wood pellets a can be input to the input port 9 of the screw conveyor 8 of the fuel supply device 4 without leakage. At the upper end of the screw conveyor 8, there are provided an input chute 11 for introducing the wood pellet a into the combustion chamber 2, and an air vent 12 for allowing outside air to pass through the input chute 11. It may be provided in the middle. The power of the screw conveyor 8 is obtained by the rotation of the motor 24.

  The rear wall 34 of the combustion chamber 2, the fuel tank 3, and the fuel supply device 4 are configured with a cooling space 17 therebetween, and outside air from the air passage 38 circulates in the cooling space 17, and combustion The combustion heat in the chamber 2 is not transferred to the fuel tank 3 and the fuel supply device 4.

  Below the combustion chamber 2, there is a combustion section 26, in which the wood pellets a that have fallen from the input chute 11 accumulate and burn, and a combustion dish 13 having a plurality of slits 14, and a combustion dish 13 The rear surface is provided with a heater 16 in a long thin tube, and the air passing through the long thin tube is heated to a high temperature (about 250 ° C. or higher) by the heater 16 and ignited by applying the high temperature air to the wood pellet a. An ignition device 15 having a structure is provided.

  On the front surface of the combustion chamber 2, there is provided a viewing window through which the flame of the wood pellets combusted in the combustion dish 13 can be confirmed from the outside in a range not reaching the heat exchange unit 5 from the combustion unit 26. The viewing window is composed of a transparent or semi-transparent heat-resistant glass 25, and the viewing window itself can be opened and closed so that the size of the viewing window can be cleaned.

  The slit 14 of the combustion dish 13 is formed in an elongated shape in either the front, rear, left, or right direction on the substantially entire surface of the combustion dish 13 while maintaining an opening width at which the input wood pellet a does not fall. A vertical slit on the side surface is connected to maintain the same opening width, and an ash collection container in which ash generated by combustion on the combustion dish 13 falls through the slit 14 and accumulates below the combustion dish 13. 29 is provided in a range covering the installation surface of the combustion dish 13.

  The heat exchanging section 5 that longitudinally cuts the combustion chamber 2 back and forth from the middle to the upper side of the combustion chamber 2 is composed of a plurality of heat radiating pipes 18. Then, warm air is supplied to the outside from the warm air outlet 20.

  The hot air exhaust port 7 at the upper end of the combustion chamber 2 is provided with an exhaust air section 6, which sucks the combustion air by the suction action of the suction fan 21 and exhausts the combustion air from the exhaust duct 22 to the outside of the machine.

  Reference numeral 23 denotes a temperature sensor, which is provided at either the exhaust duct 22 or the inlet / outlet of the suction fan 21. The temperature sensor 23, the motor 24, the heater 16, the pressure feed fan 19, and the suction fan 21 are connected to the control unit 31 and controlled. ing.

  As a result of the operation of the suction fan 21, the outside air passes directly from the air passage 38 or directly through the cooling space 17 through the slit 14 of the combustion unit 26 and the elongated cylinder of the ignition device 15, and part of the outside air passes through the charging chute 11. It reaches the combustion chamber 2. The wood pellet a is charged from the fuel tank 3 via the screw conveyor 8 into the combustion section 26 of the combustion chamber 2 and ignited by the ignition device 15, receives ventilation from the slit 14, and the wood pellet a continues to burn stably. . Thereafter, the combustion air is heat-exchanged in the heat exchanging section 5, passes through the suction fan 21 from the combustion air exhaust port 7, and is discharged out of the machine from the exhaust duct 22.

  When the operation is started, the heater 16 is energized. After the energization is completed for a predetermined time, it is determined that preheating is completed, and the motor 24 is operated to supply fuel onto the combustion dish 13. Thereafter, the suction fan 21 is started after the set time has elapsed, and the supply of fuel is stopped after supplying the wood pellet a on the combustion dish 13 for the set time. Assuming that combustion is detected when the temperature exhausted by the temperature sensor 23 reaches the set temperature (40 ° C.), the pumping fan 19 is operated, and the motor 24 is energized within the set interval and set time range to burn The fuel is supplied periodically, and thereafter, if the temperature of the temperature sensor 23 does not fall below the set temperature, it is determined that the combustion is stable and the energization to the heater 16 is stopped.

  As temperature adjustment for heating during stable combustion, the fuel supply can be adjusted in three stages, and the air volume of the suction fan 21 is controlled in three stages in accordance with the adjustment of the supply amount. In the case of fuel supply “large”, the wind speed rising up the slit 14 is about 2 to 3 m / s, the wind speed at “medium” is about 80% of the wind speed of “large”, and the wind speed at “small” is the speed of “large” About 70%.

  In the wood pellet stove 1 configured as described above, as shown in FIG. 2, a dust collecting device 27 is provided in the exhaust section 6 to allow the combustion air after dust to flow into the suction fan 21 and then a part of the combustion air Is sent to the circulation passage 28 and sprayed from the blowout portion 30 to the inner surface of the heat-resistant glass 25 of the viewing window.

  The dust collector 27 shown in FIG. 2 includes an ash collection box 33 serving as a space for collecting scattered ash on the outside of the arc by centrifugal force with the arc end of the hot air duct 32 partially arced as a double. The inside of the arc is connected to the suction fan 21. Further, an exhaust air branching portion 35 is connected to the outlet of the suction fan 21, and in this exhaust air branching portion 35, an exhaust duct 22 that discharges combustion air to the outside of the machine and a circulation passage that circulates a part of the combustion air to the combustion portion 26. 28. The exhaust air branching section 35 is preferably provided with a shutter 36 for switching the distribution amount between the exhaust duct 22 and the circulation passage 28.

  The circulation passage 28 is connected to the blowout portion 30 via the lower portion of the combustion portion 26, and the blowout portion 30 is blown out toward the inner surface of the heat resistant glass 25 of the observation window, and is uniform over the entire width of the heat resistant glass 25. In addition, it is better to flow upward without winding.

  Combustion wind guided from the combustion wind exhaust port 7 to the exhaust section 6 by the suction action of the suction fan 21 is brought to the arc surface from the combustion wind by the arc-shaped hot air duct 32 of the dust collector 27, and only the ash is collected. The combustion air collected in the box 33 and collected to separate the ash reaches the suction fan 21. Thereafter, the exhaust air branching section 35 distributes the combustion air toward the exhaust duct 22 and the circulation passage 28. Since the combustion air distributed to the circulation passage 28 does not require much, the air volume is adjusted by the shutter 36.

  The wood pellet stove 1 shown in FIG. 3 shows a configuration in which a cyclone 37 is used in the dust collector 27 of the air exhaust unit 6 of the first embodiment and a configuration in which a part of the circulation passage 28 passes through the combustion unit 26. It is. A part of the circulation passage 28 is arranged in contact with the combustion dish 13 of the combustion section 26 as shown in FIGS. 4, 5, and 6, and the back surface and both side surfaces of the combustion dish 13 as shown in FIG. 6 and the shape of the circulation passage 28 in which the back surface of the combustion dish 13 and one of the side surfaces are in contact with each other as shown in FIG.

  The combustion wind that has passed through the dust collector 27 is accumulated in the ash collection box 33 by ash contained in the combustion wind by the cyclone 37, and the combustion wind that has separated the ash is directed from the suction fan 21 to the exhaust duct 22 by the exhaust air separator 35. And in the direction of the circulation passage 28. The combustion wind guided in the direction of the circulation passage 28 is guided to the circulation passage 28 having a wide and thin contact surface on the combustion dish 13 of the combustion portion 26 and is heated by the heat of the combustion dish 13 where the wood pellets are burned. Further, heat is absorbed by the circulating passage 28 and is sprayed from the blowout portion 30 onto the inner surface of the heat-resistant glass 25 of the viewing window.

  As shown in FIG. 4, the shape of the blow-out portion 30 of the first or second embodiment has a plurality of holes that are parallel to the heat-resistant glass 25 and blow the combustion air toward the inner surface of the heat-resistant glass 25. Thus, the combustion air that circulates uniformly over substantially the entire width of the heat-resistant glass 25 is blown.

  The circulating combustion wind blown out from the blowing unit 30 of the first embodiment or the second embodiment has a high temperature. In particular, the circulating combustion wind guided to the circulation passage 28 in the form of the second embodiment is the combustion of the combustion section 26. Since it is provided in contact with the pan 13, its temperature is further increased, and high-temperature combustion air is blown onto the inner surface of the heat-resistant glass 25.

  Immediately after ignition of the wood pellet fuel or when combustion is performed at a combustion temperature of 150 ° C. or less, such as during incomplete combustion, tar is particularly generated, and tar that has risen by the combustion wind is generated in the combustion chamber 2. The eddy current may adhere to the heat-resistant glass 25 and reduce its transparency. However, since the temperature of the circulated combustion air blown from the blow-out unit 30 can be increased to 150 ° C. or higher, the heat-resistant glass 25 Even when the tar adheres to the surface, the tar disappears at the temperature of the combustion air blown and the transparency of the heat-resistant glass 25 can be maintained. Needless to say, the circulated combustion wind is always blown to the heat-resistant glass 25 from the blow-out portion 30, and the combustion wind blown from the blow-out portion 30 has a higher wind speed than the combustion wind blown from the combustion portion 26. If so, the vortex generated in the combustion chamber 2 does not approach the vicinity of the heat-resistant glass 25 and soot and ash do not adhere.

  Although the temperature of the circulating combustion air blown out from the blow-out unit 30 is slightly lowered in the first embodiment, even if it is blown out from the blow-out unit 30 into the combustion chamber 2, the temperature of the combustion chamber 2 itself is not lowered. Since the temperature of the combustion chamber 2 is equal to or higher than the temperature of the combustion chamber 2, the temperature of the combustion chamber 2 can be maintained at an efficient temperature regardless of the outside air. Has the effect of suppressing incomplete combustion and tar generation.

It is a side cross-sectional schematic diagram which shows the pellet stove used as the basic composition of this invention. 1 is a schematic side sectional view of a wood pellet stove illustrating a wood pellet fuel combustion apparatus according to a first embodiment of the present invention. It is a side section schematic diagram of the wood pellet stove which illustrates the wood pellet fuel combustion device of a second embodiment of the present invention. It is the perspective view showing the blowing part and combustion part of embodiment of FIG. It is a top view showing the blowing part and combustion part (combustion dish) of FIG. It is the top view which showed the other example of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wood pellet stove 2 Combustion chamber 3 Fuel tank 4 Fuel supply device 5 Heat exchange part 6 Exhaust part 7 Combustion air exhaust port 8 Screw conveyor 9 Input port 10 Bottom plate 11 Input chute 12 Ventilation port 13 Combustion dish 14 Slit 15 Ignition device DESCRIPTION OF SYMBOLS 16 Heater 17 Cooling space 18 Radiation pipe 19 Pressure feed fan 20 Hot air blower outlet 21 Suction fan 22 Exhaust duct 23 Temperature sensor 24 Motor 25 Heat resistant glass 26 Combustion part 27 Dust collector 28 Circulation path 29 Ash collection container 30 Blowout part 31 Control part 32 Hot air duct 33 Ash collection box 34 Rear wall 35 Exhaust air branch 36 Shutter 37 Cyclone 38 Air passage a Wood pellet

Claims (3)

Combustion tank for storing wood pellets, combustion part having an ignition device, fuel supply device for supplying wood pellets from the fuel tank to the combustion part, an air passage for supplying air to the combustion part, and combustion burned in the combustion part A wood pellet fuel combustion device comprising a combustion wind exhaust for discharging wind,
A transparent or translucent heat-resistant glass disposed at least on the front side of the combustion part, a blow-out part for supplying air toward the inner surface facing the combustion part of the heat-resistant glass, and an exhaust part and a blow-off part for the combustion wind A circulation passage that communicates with
Wood pellet fuel combustion characterized in that a part of the combustion air discharged from the exhaust portion of the combustion air is supplied to the circulation passage, and the supplied combustion air is blown out from the blow-out portion toward the inner surface of the heat-resistant glass. apparatus.   The wood pellet according to claim 1, wherein a dust collector is provided in an exhaust part of the combustion wind, and the combustion wind passes through the dust collector in the exhaust part and is blown out to the heat-resistant glass from the blow-out part. Fuel combustion device. 3. The wood pellet according to claim 1, wherein a part of the circulation passage communicating the exhaust portion and the blow-out portion of the combustion air is disposed in contact with a combustion dish in which the wood pellet in the combustion portion burns. Fuel combustion device.

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