JP2006300451A - Wood pellet combustion apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wood pellet combustion apparatus capable of evenly supplying fuel to a combustion part, and finely controlling a combustion amount by raising a filling factor of wood pellets in a fuel supplying means. <P>SOLUTION: The wood pellet combustion apparatus is composed such that a storage space b for accumulating the wood pellets is formed from an end point of a conveyance blade 33 in a screw conveyor 8 conveying the wood pellets upward, up to a discharge opening 35 of the conveyor to supply a fixed quantity of wood pellets to the combustion part, and a shredding means for shredding the wood pellets is provided on an input opening of the screw conveyor, and a falling preventing means is provided in a discharge opening direction of the screw conveyor to improve the filling factor of wood pellets, and to evenly supply the wood pellets to the combustion part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wood pellet combustion apparatus that uses wood pellets formed by compressing and processing pulverized products of driftwood and thinned wood, large sawdust, and the like.

  Conventionally, fossil fuel oil, which has been used as a fuel for combustion devices and heaters, generates carbon dioxide, which becomes a greenhouse gas, by burning, causing a problem of global warming. There is an urgent need to switch to a fuel resource that generates less carbon dioxide as a greenhouse gas as soon as possible, and that can be continuously recycled.

  Therefore, in recent years, attempts have been made to establish a recycling society by effectively using organic resources (biomass) that can be recycled and used as fuel. In particular, large sawdust, thinned wood, construction wood and driftwood that have been disposed of by incineration can be a useful resource for combustion fuel, and can be compressed into a fixed grain shape for combustors and heaters. It is starting to be used for fuel. For example, a solid fuel stove described in Japanese Utility Model Publication No. 58-190301 (Patent Publication 1) is known.

  Wood pellets that are formed into granules by compressing thinned wood, construction-generated timber, timber from thinned wood and driftwood, and large sawdust, etc., are usually in the shape of a cylinder with a diameter of 6 to 8 mm and a length of about 10 to 25 mm. The dimensions themselves are quite different. In addition, the shape and length of the wood pellets are slightly different depending on the wood to be pelletized. In particular, in the case of wood with low lignin content such as cedar wood, pelletization is not easy and the shape of the molded pellets is easily shredded in the length direction. The length is difficult to be constant.

  Since fossil fuel oil, which has been considered as a conventional combustion fuel, is liquid, it has the advantage that the amount of combustion is finely controlled and that it can be continuously performed and stable combustion can be obtained. . Even when wood pellets are used as combustion fuel, it is important to supply fuel uniformly and continuously to the combustion part, but it is supplied uniformly from the difference in the shape and length of the fuel to ensure stable combustion. It was difficult.

  Therefore, as disclosed in Japanese Patent Application Laid-Open No. 2004-191011 (Patent Publication 2), the pitch of the blades at the screw conveyor outlet of the conveying means for conveying the pellet fuel from the fuel tank to the combustion section is made shorter than the pitch of the other blades. A configuration in which a delayed fuel is filled in the conveyor and the fuel supply amount is made constant is known.

  In addition, a pellet fuel combustion apparatus that has a structure in which the inclination of the blades is reversed to the other blades at the outlet upper part of the screw conveyor so that the fuel can be stably supplied without reaching the motor part of the upper part is also known. ing.

Japanese Utility Model Publication No. 58-190301 JP 2004-191011 A

  In the above-mentioned Patent Document 2, since the pellet fuel that is transported upward by the screw conveyor is filled with the pellet fuel that is delayed in a place where the blade pitch in the direction of the outlet of the screw conveyor is short, Supply is possible, but even if the pitch is shortened near the discharge part in the screw conveyor, the blades of the carrier itself exist, so it is impossible to efficiently store the entire cross section in the screw conveyor with pellet fuel However, many voids are generated between the blades and the pellet fuel, which hinders an increase in the filling rate of the pellet fuel.

  Also, wood pellet fuel has different lengths, so when long pellet fuel is thrown into the inlet of the screw conveyor, the gap between the pellet fuel is large, so the pellets thrown from the inlet The total amount of fuel will be reduced, and no matter how much the blade pitch near the discharge port of the screw conveyor will be shortened to pack the fuel, a large space will be generated depending on the arrangement of pellet fuels. Since the gap is introduced into the combustor without narrowing, the pellet fuel cannot be stably supplied quantitatively.

  Therefore, in the present invention, a storage space that does not have a carrier for increasing the filling rate of the wood pellet fuel is provided in the fuel supply means for supplying the wood pellet fuel to the combustion section, and fuel is quantitatively supplied from the storage space. A structure capable of cutting and chopping wood pellet fuel to approximately the set length or less at the input portion of the fuel supply means, and reducing the gap between the wood pellet fuels in the fuel supply means to increase the filling rate Furthermore, since the wood pellets that have reached the storage space are provided with a fall prevention means for preventing the fall from the gap between the blades and the conveyor case, it is possible to supply the metered fuel further by the combustion section and to control the combustion amount finely. An object is to provide a wood pellet combustion apparatus.

  In order to achieve the above object, the present invention proposes a wood pellet combustion apparatus according to claims 1 to 7.

  That is, the wood pellet combustion apparatus according to claim 1 is a wood pellet combustion apparatus for supplying wood pellet fuel to the combustion section from the fuel tank by the fuel supply means. The fuel supply means has a storage space for depositing the wood pellet fuel. It is characterized by having.

  The wood pellet combustion apparatus according to claim 2 is the wood pellet combustion apparatus according to claim 1, wherein the fuel supply means is a screw conveyor that ascends and conveys the wood pellet fuel from below the fuel tank and supplies it to the combustion section. In the screw conveyor, the space between the upper end of the conveying blade provided from the substantially lower end and the lower surface of the discharge port of the screw conveyor located above is used as a storage space for wood pellets. is there.

  The wood pellet combustion apparatus according to claim 3 is characterized in that, in the wood pellet combustion apparatus according to claim 2, the storage space inside the screw conveyor is provided with a delivery blade adjacent to a substantially upper surface of the space. To do.

  The wood pellet combustion apparatus according to claim 4 is the wood pellet combustion apparatus according to claim 2 or 3, further comprising a shredding means for shredding the wood pellet fuel below the screw conveyor. Is.

  The wood pellet combustion apparatus according to claim 5 is the wood pellet combustion apparatus according to claim 4, wherein the shredding means for shredding the wood pellet fuel has a different pitch of the conveying blades within a range covering the inlet of the screw conveyor. It is characterized by being shorter than the pitch of the conveying blades.

  The wood pellet combustion apparatus according to claim 6 is the wood pellet combustion apparatus according to claim 4, wherein the shredding means for shredding the wood pellet fuel has a conveying blade more than double within a range covering the inlet of the screw conveyor. It is characterized by that.

  The wood pellet fuel device according to claim 7 is the wood pellet combustion device according to claim 2, 3, 4, 5 or claim 6, wherein the upper end of the conveying blade has a double or more conveying blade. The wood pellet fuel that has reached the storage space is prevented from falling.

  According to the wood pellet combustion apparatus of the present invention, the storage space is provided above the fuel supply means for supplying the wood pellet fuel to the combustion section so that the gap between the wood pellet fuels is reduced as much as possible to increase the filling rate. Therefore, a fixed amount can be supplied from the storage space to the combustion section to provide stable combustion.

  Furthermore, since the fuel supply means is provided with a chopping means for cutting the wood pellet fuel to a specified length or less, the gap between the wood pellet fuels in the fuel supply means can be reduced and the storage space can be reached. Since the wood pellets are provided with the fall prevention means for preventing the fall from the gap between the blade and the conveyor case, there is an effect that a fixed amount of fuel can be supplied to the combustion section.

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

  FIG. 1 is a schematic cross-sectional view of a pellet stove illustrating a wood pellet combustion apparatus according to the present invention. FIG. 2 is a cross-sectional view of the fuel supply means showing the first embodiment of the present invention, and FIG. 3 is a plan cross-sectional view showing the vicinity of the discharge port of the fuel supply means of the embodiment of the present invention. 4 is a plan sectional view showing another example of the delivery spring in FIG. FIG. 5 is a sectional view of the fuel supply means showing a second embodiment of the present invention. FIG. 6 is a sectional view of the fuel supply means showing a third embodiment of the present invention.

  In FIG. 1, 1 is a pellet stove. a is a wood pellet, and inside the pellet stove 1 is provided a combustion chamber 2 provided with a combustion portion 25 in which the wood pellet a burns, and a heat exchanging portion 5 extending from an intermediate portion of the combustion chamber 2 upward. ing. A combustion wind exhaust port 7 is provided at the upper end of the combustion chamber 2 to circulate the combustion wind C to the exhaust section 6. The combustion chamber 2 is provided with a fuel tank 3 across the rear wall 34 and the cooling space 17, and fuel supply means 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. . 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 means 4 so that the wood pellets a can be introduced into the insertion port 9 of the screw conveyor 8 of the fuel supply means 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 section 25, and an air vent 12 for allowing outside air to pass through the input chute 11. It may be provided on the way. The power of the screw conveyor 8 is obtained by the rotation of the motor 24.

  In addition, outside air flows through the cooling space 17 between the rear wall 34 of the combustion chamber 2 and the fuel tank 3 and the fuel supply means 4, and the combustion heat in the combustion chamber 2 is transferred to the fuel tank 3 and the fuel supply means. No heat transfer to 4.

  In the combustion part 25 below the combustion chamber 2, the wood pellets a flowing down from the input chute 11 accumulate and burn, and a combustion dish 13 having a plurality of slit parts 14, and a rear surface of the combustion dish 13 in a long cylinder There is provided an igniter 15 having a structure that includes a heater 16 and ignites the air passing through the long narrow cylinder by applying high temperature air (approx. 250 ° C. or higher) to the wood pellet a. .

  The slit portion 14 of the combustion dish 13 is opened in a long and narrow shape in either the front, back, left, or right direction on the substantially entire surface of the combustion dish 13 while maintaining an opening width that does not cause the dropped wood pellet a to fall. The ash after combustion of the wood pellet falls from the slit portion 14. An ash collection container 29 for depositing ash falling from the slit portion 14 is provided in a range that covers the installation surface of the combustion dish 13.

  Although not shown in the figure, a rotating body passes through the opening of the slit portion 14 and forcibly passes below the opening of the slit portion 14 in order to remove the solid ash that floats or adheres to the combustion plate 13 and is solidified. Ash removing means for dropping the ash downward may be provided.

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

  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 C by the suction action of the suction fan 21 and exhausts the combustion air C from the exhaust duct 22 to the outside of the machine. . In addition, in order to prevent the light ash that reaches the exhaust section 6 from riding on the combustion air C, the exhaust section 6 is provided with a dust collector such as a cyclone to collect and collect the dust. The configuration may be such that the combustion air C that has passed through the dust device is discharged from the suction fan 21 to the outside of the machine (not shown).

  Reference numeral 23 in FIG. 1 denotes a temperature sensor, which is provided at either the exhaust duct 22 or the inlet / outlet of the suction fan 21, and the temperature sensor 23, motor 24, heater 16, pressure feed fan 19, and suction fan 21 are connected to the control unit 31. Are controlled.

  By the operation of the suction fan 21, the outside air is directly or via the cooling space 17 in the slit portion 14 of the combustion portion 25 and the elongated cylinder of the ignition device 15, and a part of the outside air is passed through the charging chute 11 and the combustion chamber 2. Reach inside. Wood pellet a is put into the combustion chamber 2 from the fuel tank 3 via the screw conveyor 8 and ignited by the igniter 15, receives ventilation from the slit portion 14, and the wood pellet a burns. Thereafter, the combustion air C 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, and after energizing the specified time, it is determined that the preheating is completed, and the motor 24 is operated to supply the wood pellets onto the combustion dish 13. Thereafter, after the set time has elapsed, the suction fan 21 is activated to supply the wood pellet a onto the combustion dish 13 for a set time, and then the supply of the wood pellet is stopped. When the temperature exhausted by the temperature sensor 23 after ignition reaches the set temperature (40 ° C.), it is considered that combustion has been detected, the pumping fan 19 is operated, and the motor is operated within the set interval and set time range. 24 is energized to supply combustion fuel periodically, and thereafter, if the temperature of the temperature sensor 23 does not fall below the set temperature, it is determined that stable combustion is made, and 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 combustion dish vent 14 is about 2 to 3 m / s, the wind speed in “medium” is about 80% of the wind speed in “large”, and the wind speed in “small” is “large”. It is about 70% of the wind speed.

  The screw conveyor 8 of the fuel supply means 4 shown in FIG. 2 includes a screw shaft 27 in the approximate center of the conveyor case 26. The screw shaft 27 is moved by the bearings 32 of the bottom plate 28 and the upper plate 30 of the screw conveyor 8. It is fixed and can be easily rotated around the axis of the screw shaft 27, and a motor 24 is provided at one end (lower end) thereof.

  A conveying blade 33 is attached to the screw shaft 27 below the insertion port 9 with a slight distance from the bottom plate 28, and is attached with a distance of the storage space b from the upper end of the conveying blade 33 to the lower surface 36 of the discharge port 35. Yes. This storage space is always a space for storing a certain amount of wood pellets, and the screw shaft 27 is provided with a delivery blade 37 adjacent to the substantially upper surface of the storage space b, so as to move upward from the storage space b. The wood pellets that flow are allowed to flow down from the charging chute 11 to the combustion section 25. As shown in FIG. 3, three of the feed blades 37 are attached to the screw shaft 27 with an equal angle of 120 °, but two are attached at an angle of 180 ° or four at an angle of 90 °. Also good. Further, as shown in FIG. 4, it is preferable that the delivery blade 37 is joined with a shape having an action of pushing the conveyed product outward in the rotational direction and a receding angle with respect to the rotational direction. Although not shown in the figure, the linear delivery blade 37 shown in FIG. 3 may be joined to the screw shaft 37 with a receding angle.

  With the start of operation, the pellet stove 1 is started sequentially by the program of the control unit 31, and the motor 24 also periodically repeats operation in order to continue supplying ignition fuel to the combustion unit 25 and periodic supply during combustion.

  The wood pellet a charged in the fuel tank 3 rotates the screw shaft 27 by the operation of the motor 24, and the wood pellet a that contacts the conveying blade 33 in the vicinity of the inlet 9 is continuously applied to the rotation and the inlet 9 by pressure. The conveyor case 26 begins to rise. However, the wood pellet a has many gaps in the space above and below the conveying blade 33 due to the difference in particle size and in particular the length thereof, and it cannot be determined that the fixed amount is always supplied from the inlet 9. Therefore, the wood pellet a rising on the screw conveyor 8 reaches the storage space b while the places where the filling rate of the wood pellet is high and the low place are mixed depending on the conveying part.

  Since the storage space b is a portion that does not have the transport body of the transport blade 33, the lower transport blade 33 is filled with the wood pellets pushed up one after another, gradually increasing the thickness of the storage space b, and the lower surface of the discharge port 35 The thickness is increased until 36 is reached.

  While the storage space b reaches the lower surface 36 of the discharge port 35, the wood pellets a are pushed out to the inner wall surface of the conveyor case 26 by the rotation of the delivery blade 37 attached to the screw shaft 27, and from the lower surface 36 of the discharge port 35. It gradually overflows, flows down the charging chute 11 and is supplied to the combustion section 25. In particular, the delivery blade 37 may have a shape as shown in FIG. 4 so as to push the conveyed product stored in the conveyor case 26 onto the inner wall surface of the conveyor case 26.

  Although the wood pellets a of the storage space b have some gaps between the pellets, the filling rate is increased because no conveying body is interposed, and the wood pellets a are quantitatively converted to the combustion unit 25 with respect to the rotation of the screw shaft 27. It becomes possible to supply to.

  The fuel supply means of the wood pellet combustion apparatus shown in FIG. 5 has a configuration in which the fuel supply means of the pellet stove 1 shown in Embodiment 1 is provided with shredding means 41 for shredding the wood pellets a below the screw conveyor 8. It is shown. The shredding means 41 has an angle of 180 ° from the starting point of the lower end of the conveying blade 33 with the blade A38 having the same pitch as that of the conveying blade 33 provided on the screw shaft 27 in a range covering the insertion port 9 of the screw conveyor 8. The blades of the screw are provided in the screw shaft 27, and the blades of the screw have a double structure in the range covering the inlet 9, and the mounting pitch between the blades is halved.

  The rotation of the screw shaft 27 in the screw conveyor 8 tries to convey the wood pellets near the inlet 9 and the wood pellets in the fuel tank 3 flows down to enter the conveyor case 26. The opening 9 covers the range and the pitch is reduced by about half by the conveying blade 33 and the blade A38. Therefore, when the length of the wood pellet a trying to enter the conveyor case 26 is longer than the pitch, Only a part thereof can enter the conveyor case 26. Then, the wood pellet a is transported upward by the transport blade 33 in a state where a part of the wood pellet a enters the conveyor case 26, and the portion that cannot enter the conveyor case 26 is the input portion of the input port 9. The wood pellet a is shredded by the further rotation of the screw shaft 27 after the upper surface 39 is sandwiched between the contacted portion and the conveying blade 33 and the blade A38.

  Part of the wood pellets that have been shredded and not transported upward by the transport blades 33 enters the conveyor case 26 from the input port again and is transported upward again.

  Since the pitch between the blades is narrow in a range covering the input portion 9, the wood pellet a longer than the pitch width is less likely to be conveyed upward if the shape (length) is unchanged. That is, when the wood pellet a is rotated by the transport blade 33 to rotate upward, the pitch between the blades is narrowed, so there is no room for the wood pellet to escape, and the wood pellet has the blade and the input portion. The possibility of being sandwiched between the upper surfaces 39 is significantly increased. Further, the wood pellet a is shredded by further rotation of the blades, and only the shredded portion is transported upward. By repeating this, the wood pellet a conveyed upward is shorter than a certain length, but is conveyed upward with the filling ratio increased.

  And in the storage space b of the upper end of the conveyance blade | wing 33, since a conveyance body does not intervene and the shape (length) of the wood pellet conveyed upward by the shredding means 41 is remarkably small, the filling rate is further increased. As well as the effect of the feed blade 37, the wood pellet a can be quantitatively supplied to the combustion unit 25 with respect to the rotation of the screw shaft 27.

  5 is provided at an angle of 180 ° between the blade A38 and the lower portion of the conveying blade 33. However, two blades A38 are used, and the attachment angle with the conveying blade 33 is 120 °, or the blade A38 is attached. A configuration in which the number of blades A38 is made plural and the pitch between the blades is made finer, such as three mounting angles with the conveying blades 33 is set, and the pitch of the conveying blades 33 is shortened in a range covering the insertion port 9. It may be configured, and the shape (length) of the wood pellet a may be more finely cut to further increase the filling rate (not shown).

  The fuel supply means of the wood pellet combustion apparatus shown in FIG. 6 is the same as the fuel supply means of the pellet stove 1 shown in the first and second embodiments. The fall prevention means 42 prevents the wood pellets from dropping at the upper end of the conveying blade 33. It is equipped with. This fall prevention means 42 is a blade B40 having the same pitch as that of the spiral blade 33, and is attached to the screw shaft 27 at an angle of 180 ° with the end point of the upper end of the attachment of the spiral blade 33. This blade B40 shown in FIG. 6 is provided with a length of half pitch (half winding) from the end of the upper end of the conveying blade 33, but a pitch number of about 1 pitch (one turn) is sufficient. It is.

  The wood pellet a pushed up by the spiral blade 33 by the rotation of the screw shaft 27 is pushed up to the height at which the lower starting point of the blade B40 is provided as it moves upward, and the pitch width is halved. Reach inside and continue to rise. The wood pellet gradually fills the charging chute 11 due to the push-out effect of the feed blade 37 when the storage space b without the carrier is filled and the upper surface of the storage space b on the lower surface 36 of the discharge port 35 is reached while increasing the filling rate. And flows into the combustion section 25.

  The blade B40 of the fall prevention means 42 and the conveying blade 33 give a force to push the wood pellets further upward, and reduce the amount of wood pellets falling from the gap between the inner surface of the conveyor case 26 and each blade. Therefore, the wood pellets can be efficiently conveyed upward.

  Further, when the wood pellet is lifted and transported only by the transport blade 33 up to the storage space b, it is formed slightly before the end point of the upper end of the transport blade 33 due to the pushing-up action of the wood pellet in the rotation direction. The upper surface of the storage space b has an inclined slope due to the mountain on the upper surface of the storage space b, resulting in a problem in that the difference in the amount of wood pellets supplied to the input chute 11 from each delivery blade 37 occurs.

  Therefore, since the end points of the upper ends of the blades B40 and the conveying blades 33 have the same height, two peaks are formed on the upper surface of the storage space b formed by pushing up the wood pellets by the rotation of the screw shaft 27. Thus, the level difference on the surface of the storage space b is greatly reduced, so that the amount of wood pellets flowing down the charging chute 11 by the delivery blade 37 can be stabilized.

  In addition, although the space | interval attached to the screw shaft 27 of the blade | wing B40 shown in FIG. 6 and the conveyance blade 33 is provided with the angle of an end point at 180 degrees, the blade B40 is made into two sheets and the attachment angle with the conveyance blade 33 is 120 degrees, Alternatively, if the pitch between the blades is made finer by using a plurality of blades B40, such as three blades B40 and an attachment angle of 90 ° with the conveying blades 33, peaks formed on the surface of the storage space b And the difference between the low surfaces is further reduced, and the amount of wood pellets flowing into the charging chute 11 can be stabilized.

  The configuration in which the blades B40 and the conveying blades 33 are double or more has an effect of increasing the lifting ability to push up the wood pellets, and can increase the accumulation layer in the storage space. The thicker the storage space b is, the smaller the level difference caused by the rotation of the carrier on the upper surface of the layer, and the stable supply of the wood pellets to the combustion unit 25 becomes possible.

1 is a schematic cross-sectional view of a pellet stove illustrating a wood pellet combustion apparatus according to the present invention. Sectional drawing of the fuel supply means which shows the 1st Embodiment of this invention. FIG. 3 is a plan sectional view showing the vicinity of the discharge port of the fuel supply means according to the embodiment of the present invention. FIG. 4 is a plan sectional view showing another example of the delivery spring in FIG. 3. Sectional drawing of the fuel supply means which shows the 2nd Embodiment of this invention. Sectional drawing of the fuel supply means which shows the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pellet stove 2 Combustion chamber 3 Fuel tank 4 Fuel supply means 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 unit 15 Ignition device DESCRIPTION OF SYMBOLS 16 Heater 17 Cooling space 18 Radiation pipe 19 Pressure feed fan 20 Warm air blower outlet 21 Suction fan 22 Exhaust duct 23 Temperature sensor 24 Motor 25 Combustion part 26 Conveyor case 27 Screw shaft 28 Bottom plate 29 Ash collection container 30 Upper plate 31 Control part 32 Bearing 33 Transport blade 34 Rear wall 35 Discharge port 36 Lower surface 37 Delivery blade 38 Blade A
39 Top of inlet 40 Blade B
41 Shredding means 42 Fall prevention means a Wood pellet b Storage space C Combustion air

Claims (7)

In the wood pellet combustion apparatus for supplying wood pellet fuel to the combustion section by the fuel supply means from the fuel tank,
A wood pellet combustion apparatus, wherein the fuel supply means includes a storage space for depositing wood pellet fuel. The fuel supply means is a screw conveyor that ascends and conveys the wood pellet fuel from below the fuel tank and supplies it to the combustion section,
Inside the screw conveyor, the space between the upper end of the conveying blade provided from substantially the lower end and the lower surface of the discharge port of the screw conveyor located above is used as a storage space for wood pellets. 1. A wood pellet combustion apparatus according to 1.   3. The wood pellet combustion apparatus according to claim 2, wherein the storage space inside the screw conveyor is provided with a delivery blade adjacent to a substantially upper surface of the space.   The wood pellet combustion apparatus according to claim 2 or 3, further comprising a shredding means for shredding the wood pellet fuel below the screw conveyor.   The wood pellet combustion according to claim 4, wherein the shredding means for shredding the wood pellet fuel makes the pitch of the conveying blades shorter than the pitch of the other conveying blades in a range covering the inlet of the screw conveyor. apparatus.   5. The wood pellet combustion apparatus according to claim 4, wherein the shredding means for shredding the wood pellet fuel has double or more conveying blades in a range covering the inlet of the screw conveyor. The upper end of the conveyance blade is provided with a fall prevention means that makes the conveyance blade doubly or more so as to prevent the fall of the wood pellet fuel that has reached the storage space. The wood pellet combustion apparatus of Claim 5 or Claim 6.

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