Solid fuel combustion device

Abstract

To provide a solid fuel combustion device that can restrain damage to the device and an abnormal stop caused by a foreign body mixed in fuel.SOLUTION: A solid fuel combustion device comprises: a combustion chamber 14 for burning solid fuel; a combustion plate 15 provided in the combustion chamber 14, and on which the solid fuel to be burned is placed on a surface; a solid fuel introduction part 12 for introducing the solid fuel onto the combustion plate 15; a rake 16 provided on the combustion plate 15; and a driving part 17 for rotating and driving at least one of the combustion plate 15 and the rake 16. The rake 16 comprises a lifting mechanism 168 for releasing a foreign body by lifting the rake 16 when the foreign body is caught between itself and the combustion plate 15.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a solid fuel combustion device, and more particularly to a solid fuel combustion device capable of effectively suppressing damage to the device, abnormal shutdown, etc., caused by foreign matter mixed in the fuel. [Background technology]

[0002] Conventionally, in a grain drying system for drying grains, a technology is known in which rice husks, which are an example of biomass fuel, are burned as fuel for a combustion device that supplies a heat source for drying. As technologies related to such combustion devices, grain drying equipment and solid fuel combustion devices that can effectively utilize the thermal energy of biomass combustion hot air generated in a biomass combustion furnace are known (for example, see Patent Documents 1 and 2).

[0003] The grain drying equipment described in Patent Document 1 has a biomass combustion furnace that generates hot air based on the combustion heat of biomass fuel and outside air taken in from the outside, and a circulating grain dryer equipped with a grain drying section to which the hot air generated in the biomass combustion furnace is supplied via a hot air supply piping.

[0004] The solid fuel combustion device described in Patent Document 2 includes a combustion chamber for burning rice husks, a combustion plate provided in the combustion chamber, a solid fuel introduction section for introducing the rice husks onto the combustion plate, a rake provided on the combustion plate, and a drive section for rotating at least one of the combustion plate and the rake. The rake provided on the combustion plate is intended to level the introduced rice husks by spreading them on the combustion plate, and to push out a portion of the ash that has accumulated to a predetermined thickness or more among the ash that has been burned on the combustion plate, and to move it toward the outside of the combustion plate. The rake is also said to have the effect of continuously rotating on the combustion plate, thereby continuously coming into contact with the ash on the combustion plate and stirring the ash on the combustion plate.

[0005] In addition to the combustion device that uses rice husks as fuel as in Patent Document 2, various heating devices are also known that can use, for example, irregular pieces of wood made by cutting or crushing construction waste or thinning materials into small pieces as solid fuel materials (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2013 / 057838 [Patent Document 2] International Publication No. 2019 / 171466 [Patent Document 3] JP 2012-225530 A Summary of the Invention [Problem to be solved by the invention]

[0007] The solid fuel combustion device described in Patent Document 2 uses rice husks, which are the outer skin of grains, as fuel. For this reason, depending on the storage method and storage environment of the rice husks, foreign objects may be mixed into the rice husks that are used as fuel. For example, rice husks may be stored by piling them up on the ground such as sand and gravel, and when they are collected, foreign objects such as pebbles may be collected together. If these foreign objects are supplied together with the fuel, they may be caught between the combustion plate and the rake, causing damage to components such as the combustion plate and the rake. In particular, when the rice husks are not well managed, these foreign objects may become more problematic. In addition, the combustion device described in Patent Document 3 also uses combustible materials such as wood chips other than rice husks as fuel, so in addition to the foreign objects that are mixed in when collected from the storage place as described above, foreign objects that cause damage to components such as the combustion plate and the rake may be included in the fuel.

[0008] The present invention has been made in consideration of the problems of the prior art, and aims to provide a solid fuel combustion device that can effectively prevent damage to the device or abnormal shutdown caused by foreign matter mixed in the fuel. [Means for solving the problem]

[0009] According to the present invention, there is provided a solid fuel combustion device as described below.

[0010] [1] a combustion chamber for burning a solid fuel; a combustion plate provided in the combustion chamber, the solid fuel being capable of being placed on a surface thereof; a solid fuel introduction section for introducing the solid fuel onto the combustion plate; A rake provided on the combustion plate; A drive unit that rotates at least one of the combustion plate or the rake, The solid fuel combustion device, wherein the rake has a lifting mechanism that lifts the rake to allow a foreign object to escape when the foreign object becomes caught between the rake and the combustion plate.

[0011] [2] The solid fuel combustion device described in [1], wherein the rake comprises an approximately cylindrical rake main shaft and a rake shaft located inside the rake main shaft, and the lifting mechanism of the rake comprises a camshaft that slidably holds the rake main shaft and the rake shaft, and a cam groove that engages with the camshaft provided on at least one of the rake main shaft and the rake shaft.

[0012] [3] The solid fuel combustion device described in [2], wherein the cam groove is formed at an angle in a direction to convert the rotational driving force received by the rake when the foreign object becomes caught into a force that lifts the rake main shaft.

[0013] [4] The solid fuel combustion device described in [2], further comprising a load application unit that applies a vertically downward load to the camshaft.

[0014] [5] The solid fuel combustion device according to [1] or [2], wherein the solid fuel is a biomass fuel.

[0015] [6] The solid fuel combustion device described in [5], wherein the solid fuel is rice husk. Effect of the Invention

[0016] The solid fuel combustion device of the present invention has an effect of effectively suppressing damage to the device or abnormal stoppage caused by foreign matter mixed in the fuel. Specifically, in the solid fuel combustion device of the present invention, the rake provided on the combustion plate has a lifting mechanism that lifts the rake to allow foreign matter to escape. This makes it possible to effectively deal with situations in which foreign matter such as pebbles mixed in the fuel gets stuck between the combustion plate and the rake and inhibits the rotation of the rake, and extremely effectively prevents damage to components such as the combustion plate and the rake due to foreign matter getting caught. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic configuration diagram showing a grain drying system in which an embodiment of a solid fuel combustion apparatus of the present invention is installed. [Diagram 2] FIG. 2 is a front view of the solid fuel combustion device. [Diagram 3] FIG. 2 is a schematic diagram showing the internal structure of a solid fuel combustion device. [Figure 4] FIG. 2 is a plan view showing the internal structure of the solid fuel combustion device. [Diagram 5] 4 is an enlarged schematic view showing a part of a combustion chamber in the internal structure of the solid fuel combustion apparatus shown in FIG. 3. FIG. [Diagram 5] FIG. 2 is a front view of the burner plate and rake. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The following describes the embodiments of the present invention, but the present invention is not limited to the following embodiments. In other words, it should be understood that the scope of the present invention includes any modifications and improvements to the following embodiments based on the ordinary knowledge of a person skilled in the art without departing from the spirit of the present invention.

[0019] One embodiment of the solid fuel combustion apparatus of the present invention is a solid fuel combustion apparatus 10 as shown in Figs. 2 to 4. The solid fuel combustion apparatus 10 of this embodiment is an apparatus for burning solid fuel, and can be used, for example, in a grain drying system 1 as shown in Fig. 1. Here, Fig. 1 is a schematic configuration diagram showing a grain drying system in which one embodiment of the solid fuel combustion apparatus of the present invention is installed. Fig. 2 is a front view of the solid fuel combustion apparatus. Fig. 3 is a schematic diagram showing the internal structure of the solid fuel combustion apparatus. Fig. 4 is a plan view showing the internal structure of the solid fuel combustion apparatus.

[0020] First, a grain drying system 1 shown in FIG. 1 in which the solid fuel combustion apparatus 10 of this embodiment can be used will be described. As shown in FIG. 1, the grain drying system 1 includes the solid fuel combustion apparatus 10, a rice husk supplying apparatus 20, a grain dryer 30, a hot air supplying duct 40, and a blower 50. An example in which the heat generated by the solid fuel combustion apparatus 10 of this embodiment is used for grain drying will be described below. Note that the use of the solid fuel combustion apparatus 10 is not limited to the grain drying system 1 shown in FIG. 1, and it can be used for purposes other than grain drying. For example, the solid fuel combustion apparatus 10 can also be used as a heat utilization device such as a heating device or a heating and drying device.

[0021] The solid fuel combustion apparatus 10 in the grain drying system 1 shown in Fig. 1 is an apparatus that burns rice husks, which are the outer skin of rice, which is an example of grain, as a solid fuel and exchanges heat with air supplied from a blower 50 or the like. The solid fuel combustion apparatus 10 supplies heat generated by burning the rice husks to a heat supply target such as a grain dryer 30. The solid fuel combustion apparatus 10 will be described in detail later.

[0022] The rice husk supplying device 20 is a device that supplies rice husks during operation of the solid fuel combustion device 10. The rice husk supplying device 20 includes a hopper for storing rice husks, a supply path such as a screw for transporting the rice husks from the hopper to the solid fuel combustion device 10, and power supplied from the hopper.

[0023] The grain dryer 30 is a device that dries grains such as rice by using heat generated by the solid fuel combustion device 10. Although two grain dryers 30 are provided in Fig. 1, the number of grain dryers 30 is not limited.

[0024] The hot air supply duct 40 is a duct for sending hot air heated by the heat generated by the solid fuel combustion device 10 to the grain dryer 30. The hot air supply duct 40 is made of a material corresponding to the temperature of the hot air sent to the grain dryer 30, and is formed with dimensions corresponding to the supply amount.

[0025] The blower 50 is attached to the side of the solid fuel combustion apparatus 10. The air sent by the blower 50 passes between the exterior body 11 and the combustion chamber 14 and is discharged from the hot air supply port 13. The blower 50 sends air to a heat exchanger provided on the upper part of the solid fuel combustion apparatus 10. The air sent to the heat exchanger becomes hot air by receiving heat generated by the solid fuel combustion apparatus 10 and is sent to the grain dryer 30. Although not shown, a combustion air fan may be attached to the solid fuel combustion apparatus 10. The combustion air fan (not shown) sends air required for the combustion of rice husks by the solid fuel combustion apparatus 10 from the outside. For example, the combustion air fan (not shown) controls the amount of air sent to the solid fuel combustion apparatus 10 to control the combustion state of the solid fuel combustion apparatus 10.

[0026] In the grain drying system 1, the configurations of the rice husk supplying device 20 and the blower 50 are not limited to the above-mentioned examples, and various configurations can be used.

[0027] Next, the configuration of the solid fuel combustion apparatus 10 of this embodiment will be described.

[0028] As shown in Figs. 2 to 5, the solid fuel combustion apparatus 10 includes an exterior body 11, a solid fuel introduction section 12, and a hot air supply port 13. The solid fuel combustion apparatus 10 heats air by burning rice husks, which are an example of biomass fuel, as solid fuel. Here, Fig. 2 is a view of the solid fuel combustion apparatus 10 seen from a direction opposite to the extension direction of the hot air supply duct 40 in Fig. 1. Hereinafter, the solid fuel combustion apparatus 10 will be described with the surface opposite to the extension direction of the hot air supply duct 40 as the front. Here, Fig. 2 is a front view of the solid fuel combustion apparatus. Fig. 3 is a schematic view showing the internal structure of the solid fuel combustion apparatus. Fig. 4 is a plan view showing the internal structure of the solid fuel combustion apparatus (particularly, the periphery of the combustion plate 15). Fig. 5 is a front view of the combustion plate and the rake.

[0029] The exterior body 11 forms the outer shape of the solid fuel combustion device 10. The exterior body 11 is composed of a panel 111 that separates the inside and outside of the device to accommodate components of the solid fuel combustion device 10 such as a combustion chamber described below, a frame 112 that holds the components and determines the outer shape of the device, and the like.

[0030] The solid fuel introduction section 12 is a member for supplying rice husks as a solid fuel supplied from a rice husk supplying device 20 (see FIG. 1) into the combustion chamber .

[0031] The hot air supply port 13 is an opening for sending out the hot air that has been subjected to heat exchange to the hot air supply duct 40 (see FIG. 1). The hot air supply port 13 communicates with the hot air supply duct 40 (see FIG. 1).

[0032] The solid fuel combustion device 10 includes, inside the exterior body 11, a combustion chamber 14, a drive unit 17, an exhaust unit 18, and an air supply unit 19.

[0033] The combustion chamber 14 constitutes a space in which rice husks as solid fuel are burned. The combustion chamber 14 is made of a material that can withstand the combustion of the solid fuel. The combustion chamber 14 includes a combustion plate 15 and a rake 16 in the space in which the solid fuel is burned.

[0034] The combustion plate 15 is provided inside the combustion chamber 14. The combustion plate 15 has a surface that is, for example, flat so that the solid fuel to be burned (for example, rice husks) can be placed thereon.

[0035] The combustion plate 15 is formed, for example, in a circular shape in a plan view to match the shape and operating range of the rake 16 (see, for example, FIG. 4). The combustion plate 15 is composed of a combustion table 151 and a combustion plate body 152. The combustion table 151 is supported by the panel 111. The combustion table 151 is formed in a cylindrical shape. The combustion plate body 152 is placed on the upper part of the combustion table 151. The combustion table 151 makes the height of the combustion plate body 152 higher than the bottom surface of the combustion chamber 14.

[0036] The combustion plate body 152 is formed of a heat-resistant material, such as a heat-resistant stainless steel plate, so that the solid fuel to be burned at high temperature is placed on the surface. The above-mentioned stainless steel plate forming the combustion plate body 152 may be formed as a single plate, or may be formed by arranging multiple plates. The combustion plate body 152 is a stainless steel punched metal-shaped plate material with multiple holes that penetrate between the front and back sides. The holes allow air to pass between the front and back sides of the combustion plate body 152.

[0037] The combustion plate body 152 is not limited to the stainless steel punched metal shape as described above, but may be, for example, a porous ceramic plate material with air permeability, or may be a material other than ceramic that can withstand high temperatures. In addition, the planar shape of the combustion plate body 152 is not limited to the circular shape as described above.

[0038] An air chamber 153 is formed inside the combustion plate 15 by the combustion stand 151 and the combustion plate body 152 provided on the panel 111. The air chamber 153 is filled with air supplied from a combustion air fan (not shown) via the air supply unit 19. The air in the air chamber 153 passes through holes in the combustion plate body 152 and is discharged upward (towards the surface of the combustion plate body 152).

[0039] The solid fuel introduction section 12 is disposed so that its tip portion is located above the vicinity of the center of the combustion plate 15. Therefore, the solid fuel introduction section 12 can introduce the solid fuel above the vicinity of the center of the combustion plate 15. For example, when rice husks are used as the solid fuel, the solid fuel introduction section 12 can supply the amount of rice husks required for the set temperature (for example, 7 to 60 kg / h). The input amount of solid fuel is arbitrarily determined, for example, when the solid fuel combustion device 10 is started up or during operation.

[0040] The solid fuel introduction section 12 continuously inputs the solid fuel. When rice husks are used as the solid fuel, if the input rate of rice husks is, for example, 60 kg / h, 1 kg of rice husks is input per minute for 60 minutes. The solid fuel introduction section 12 is provided with a mechanism for continuously inputting rice husks per hour, such as a screw conveyor (not shown), at the base of the solid fuel introduction section 12. The solid fuel introduction section 12 controls the input rate of rice husks by controlling the rotation speed of the screw conveyor. The solid fuel combustion device 10 can control the combustion temperature and combustion time of the rice husks by adjusting the rotation speed of the rake 16 and the input rate of rice husks.

[0041] The drive unit 17 is for driving and rotating at least one of the combustion plate 15 and the rake 16. For example, when the shaft of the rake 16 is located approximately at the center of the combustion plate 15, the drive unit 17 is configured with an electric motor, gears, etc., in order to drive and rotate the rake 16 about the shaft. Note that the drive unit 17 may be one that drives and rotates the combustion plate 15, or may be one that drives and rotates both the combustion plate 15 and the rake 16.

[0042] The rake 16 is provided on the combustion plate 15. The rake 16 is a member for leveling the solid fuel supplied from the solid fuel introduction section 12 onto the combustion plate 15 and the ash generated by the combustion of the solid fuel. Therefore, there are no particular limitations on the specific shape, etc., of the rake 16, so long as it is configured to move and agitate the solid fuel and ash on the combustion plate 15 to promote combustion. The configuration of the rake 16 shown in Figs. 3 to 5 will be described below.

[0043] 3 to 5, the rake 16 has a rake main shaft 161a and a rake shaft 161b that serve as an axis portion, a support portion 162, first rake portions 163a and 163b, second rake portions 164a and 164b, and third rake portions 165a and 165b. The rake 16 further has a lifting mechanism 168 that lifts the rake 16 when a foreign object becomes caught between the rake 16 and the combustion plate 15, to allow the foreign object to escape.

[0044] The solid fuel combustion device 10 has a lifting mechanism 168 that lifts the rake 16 to allow the foreign object to escape when the foreign object becomes caught between the rake 16 and the combustion plate 15 as described above, thereby effectively preventing damage to the device (e.g., the combustion plate 15 or rake 16) due to foreign object getting caught and abnormal shutdown of the solid fuel combustion device 10.

[0045] For example, since the conventional solid fuel combustion apparatus does not have the lifting mechanism 168 for lifting the rake 16 as described above, when a foreign object is caught between the rake 16 and the combustion plate 15, the foreign object must be crushed by the relative rotational force between the rake 16 and the combustion plate 15, or the foreign object must be forcibly removed. For this reason, depending on the hardness and shape of the foreign object, the components may be damaged, or the operation may be stopped due to an overload of the motor that applies the rotational force. On the other hand, in the solid fuel combustion apparatus 10 of this embodiment, when a foreign object is caught between the rake 16 and the combustion plate 15 (when the foreign object is caught), the lifting mechanism 168 lifts the rake 16 to release the foreign object and restore the normal rotation state. For this reason, the solid fuel combustion apparatus 10 can effectively prevent damage caused by the foreign object that has entered the apparatus, and the apparatus is less likely to stop due to the entry of the foreign object, and can continue to operate smoothly.

[0046] 3 to 5, rake 16 has a rake main shaft 161a and a rake shaft 161b that form the shaft portion, which are located approximately at the center of combustion plate 15. Rake main shaft 161a has a substantially cylindrical shape, and rake shaft 161b is disposed inside rake main shaft 161a.

[0047] In the solid fuel combustion device 10, it is preferable that the lifting mechanism 168 of the rake 16 has a camshaft 168a that slidably holds the rake main shaft 161a and the rake shaft 161b, and a cam groove 168b that engages with the camshaft 168a provided on at least one of the rake main shaft 161a and the rake shaft 161b. For example, a V-shaped groove (cam groove 168b) is formed in the rake shaft 161b for driving the rake 16. The rake shaft 161b is connected to the rake main shaft 161a via the camshaft 168a in a manner that penetrates the cam groove 168b. With this configuration, when a foreign object or the like is caught during the rotation of the rake 16 and a stress that inhibits the rotation of the rake 16 is applied, the rake 16 rises via the camshaft 168a by sliding up the V-shaped cam groove 168b, and the caught foreign object can be released. In particular, by using the above-described structure (cam mechanism), the lifting mechanism 168 of the rake 16 can be realized with a simpler configuration.

[0048] In the above explanation of the configuration of the lifting mechanism 168, an example has been described in which the rake 16 rotates on the combustion plate 15, but the solid fuel combustion device 10 may be configured so that at least one of the combustion plate 15 and the rake 16 is rotationally driven by the drive unit 17. In other words, the combustion plate 15 may rotate, and a relative rotational force may act on the rake 16 on the combustion plate 15. Even in the case where the combustion plate 15 is rotationally driven by the drive unit 17, the lifting mechanism 168 using the above-mentioned cam mechanism can lift the rake 16 when a stress that inhibits the relative rotation of the rake 16 is applied.

[0049] The cam groove 168b is not limited to the V-shaped groove described above, as long as it is inclined in a direction that converts the rotational driving force that the rake 16 receives when a foreign object gets caught into a force that lifts the rake main shaft 161a. On the other hand, by making the cam groove 168b a V-shaped groove, the rake 16 can be lifted by the lifting mechanism 168 regardless of the rotational direction of the rake 16.

[0050] For example, rake shaft 161b may be provided with cam groove 168b in the opposite direction to the rotation direction of rake 16 or in the diagonally upward direction in the same direction as the rotation direction of combustion plate 15. With this configuration, when rake 16 is rotating in the forward direction, cam groove 168b of rake shaft 161b can be used to raise rake 16 and release any trapped foreign matter.

[0051] Furthermore, when the cam groove 168b for lifting the rake 16 when the rake 16 rotates in the forward direction relative to the rake shaft 161b is provided as described above, the rake shaft 161b may further be provided with a cam groove 168b in the same direction as the rotation direction of the rake 16 or in an obliquely upward direction opposite to the rotation direction of the combustion plate 15. With this configuration, even when the rake 16 is rotating in the reverse direction, the cam groove 168b of the rake shaft 161b can be used to lift the rake 16 and release any trapped foreign matter.

[0052] The cam groove 168b may be provided on the rake main shaft 161a. For example, the cam groove 168b may be provided on the rake main shaft 161a in the same direction as the rotation direction of the rake 16 or in the diagonally downward direction opposite to the rotation direction of the combustion plate 15. With this configuration, when the rake 16 rotates in the forward direction, the cam groove 168b of the rake main shaft 161a can be used to raise the rake 16 and release any trapped foreign matter.

[0053] Furthermore, when the cam groove 168b for lifting the rake 16 when the rake 16 rotates in the forward direction is provided on the rake main shaft 161a as described above, the rake main shaft 161a may further be provided with a cam groove 168b in the opposite direction to the rotation direction of the rake 16 or in the diagonally downward direction in the same direction as the rotation direction of the combustion plate 15. By configuring in this manner, even when the rake 16 is rotating in the reverse direction, the cam groove 168b of the rake main shaft 161a can be used to lift the rake 16 and release any trapped foreign matter.

[0054] There are no particular limitations on the shape of the cam groove 168b, but for example, the rise width of the rake 16 can be adjusted according to the shape of the cam groove 168b. For example, in the solid fuel combustion device 10, the rake main shaft 161a is configured to be able to move vertically upward up to a maximum of 16 mm to release any trapped foreign matter. When the trapped foreign matter is released and the load that inhibits the rotation of the rake 16 is removed, the cam shaft 168a returns to the original position of the cam groove 168b (i.e., the position before it rose), and the rake main shaft 161a returns to the height of the initial state.

[0055] The lifting mechanism 168 for lifting the rake 16 may further include a load applying unit 169 for applying a load to the camshaft 168a in a vertically downward direction. The load applying unit 169 may be, for example, a spring material such as a preload spring. For example, one end of the spring material as the load applying unit 169 is connected to the camshaft 168a via a spring joint, and the other end is connected to the vertically lower side of the device via another spring joint. With this configuration, the rake 16 is fixed at the lowest position of the cam groove 168b when no extra stress that inhibits rotation is applied to the rake 16. On the other hand, when a load (i.e., an allowable load) greater than a certain value determined by the load applying unit 169 is applied to the rake 16, the camshaft 168a begins to shift in a direction climbing up the cam groove 168b. By providing an allowable load for the lifting mechanism 168 in this way, when a foreign object gets caught in the rake 16, the rotational force of the rake 16 can attempt to remove or crush the foreign object up to a certain load, and the force for crushing the foreign object can be increased by adjusting the allowable load. The allowable load of the load applying portion 169 can be set by the strength of a spring material such as a preload spring. For example, it can be set appropriately taking into consideration the resistance to the substantial smoothing portions of the rake 16 (for example, the first rake portions 163a, 163b and the second rake portions 164a, 164b).

[0056] The support portion 162 of the rake 16 is attached so as to be oriented perpendicular or approximately perpendicular to the rake main shaft 161a serving as the shaft portion. The support portion 162 is disposed toward the radially outer side of the combustion plate body 152 with the rake main shaft 161a as the center. In the solid fuel combustion device 10, two support portions 162 are disposed toward the radially outer side of the combustion plate body 152 with the rake main shaft 161a as the center, and each support portion 162 is disposed in the opposite direction with the rake main shaft 161a as the center. The length of each support portion 162 is longer than the radius of the combustion plate body 152. That is, the radially outer end portion of each support portion 162 is located outside the outer circumferential edge of the combustion plate body 152.

[0057] First rake portions 163a, 163b and second rake portions 164a, 164b are disposed on the support portion 162 of the rake 16 as substantial leveling portions of the rake 16. In addition, third rake portions 165a, 165b are disposed on the end portion of the support portion 162 on the outer circumferential edge side of the combustion plate body 152 for raking up ash that has fallen from the combustion plate body 152 onto the upper surface of the combustion table 151 during operation of the solid fuel combustion apparatus 10.

[0058] The first rake parts 163a and 163b are provided as a pair near the center of the combustion plate 15 of the support part 162. The first rake parts 163a and 163b are rod-shaped members having an approximately L-shape. One end of the approximately L-shaped rod-shaped member constituting the first rake parts 163a and 163b is connected downward to the support part 162, and is bent toward the center of the combustion plate main body 152 just before contacting the combustion plate main body 152. The bent part of the rod-shaped member is configured to be approximately parallel to the surface of the combustion plate main body 152 so as to maintain a certain distance from the surface. The first rake parts 163a and 163b level the solid fuel (e.g., rice husks) introduced from the solid fuel introduction part 12 to the vicinity of the center of the combustion plate main body 152 on the combustion plate main body 152 by rotating the rake 16. The first rake portions 163a and 163b also come into contact with the burning solid fuel and ash produced by the combustion, stirring them up. Then, the first rake portions 163a and 163b push and move the solid fuel and ash that have accumulated to a level that exceeds the clearance between the surface of the combustion plate main body 152 and the solid fuel and ash to the outside of the combustion plate 15.

[0059] The second rake portions 164a, 164b are provided as a pair on the outer side of the combustion plate 15 of the support portion 162. The second rake portions 164a, 164b are also rod-shaped members having an approximately L-shape. One end of the approximately L-shaped rod member constituting the second rake portions 164a, 164b is connected downward to the support portion 162, and is bent toward the approximately center of the combustion plate body 152 just before contacting the combustion plate body 152. However, the other bent end side of the rod member constituting the second rake portions 164a, 164b is bent at a predetermined angle θ with respect to the support portion 162, starting from the support portion 162, when viewed from a direction facing the extension direction of the rake main shaft 161a (see, for example, FIG. 4). That is, the rod-like members of the second rake parts 164a and 164b, which are substantially L-shaped, are bent toward the direction of the rotational direction at an angle θ with respect to the direction toward the center of the combustion plate body 152. The second rake parts 164a and 164b also level the solid fuel and ash by rotating the rake 16, spreading them on the combustion plate body 152. In particular, by adopting the above-mentioned configuration, it is possible to push out a portion of the ash that has accumulated to a predetermined thickness or more among the ash burned on the combustion plate 15, and move it to the outside of the combustion plate 15, that is, toward the combustion table 151. The second rake parts 164a and 164b also have the effect of stirring the solid fuel and ash being burned on the combustion plate body 152 by continuously contacting the solid fuel and ash being burned as the rake 16 rotates.

[0060] The third rake parts 165a and 165b are substantially rectangular plate materials. The third rake parts 165a and 165b are provided so that the long sides are substantially perpendicular to the combustion table 151 when the rake 16 is attached to the combustion plate 15. The third rake parts 165a and 165b are provided on the third rake support members 166a and 166b that extend vertically downward from the end of the support part 162 on the outer periphery side of the combustion plate main body 152. The third rake parts 165a and 165b are provided at positions facing the combustion table 151 when the rake 16 is attached to the combustion plate 15. Therefore, the third rake parts 165a and 165b come into contact with ash that has fallen from the combustion plate main body 152 onto the upper surface of the combustion table 151 during operation of the solid fuel combustion device 10.

[0061] It is preferable that the first rake portions 163a, 163b and the second rake portions 164a, 164b are configured so that their respective bottom ends (i.e., the bent portions of the rod-shaped members in a substantially L-shape) do not come into contact with the upper surface of the combustion plate body 152, that is, so that a predetermined thickness of ash remains. Here, it is preferable that the positions of the bottom ends of the first rake portions 163a, 163b and the second rake portions 164a, 164b are such that the distance between the bottom end of the rake 16 and the upper surface of the combustion plate body 152 is, for example, about 2 to 5 cm, so that the height of the ash is an appropriate value (for example, 1 to 5 cm), assuming that the amount of air sent into the inside of the combustion chamber 14 is determined by the air permeability of the combustion plate body 152 containing ash.

[0062] Here, if a foreign object is mixed in the solid fuel, the foreign object that is obviously smaller than the distance between the bottom end of the rake 16 and the upper surface of the combustion plate body 152 described above is unlikely to hinder the rotation of the rake 16. Also, if the foreign object is obviously larger than the above distance and can be removed by the rotational force of the rake 16, it will be pushed out together with the solid fuel and ash by the rotation of the rake 16 and moved to the outside of the combustion plate 15. On the other hand, a foreign object of a size similar to the above distance will easily get caught between the rake 16 and the combustion plate 15 and cause damage to components such as the combustion plate 15 and the rake 16. The solid fuel combustion device 10 has a lifting mechanism 168 that lifts the rake 16 to release the foreign object when the foreign object is caught between the combustion plate 15 and the rake 16, so that the device can be effectively prevented from being damaged even if the above-mentioned foreign object is mixed in the solid fuel. In addition, if the foreign object is one that hinders the rotation of the rake 16, even if the foreign object is not caught between the combustion plate 15, the lifting mechanism 168 will function to lift the rake 16 when the above-mentioned allowable load is exceeded, in an attempt to avoid the foreign object.

[0063] There is no particular restriction on the material of the rake 16, but it is preferable that the rake 16 is made of a hard, heat-resistant material such as metal. For example, the parts that come into contact with the burning flame, such as the rake main shaft 161a, the support part 162, the first rake parts 163a, 163b, the second rake parts 164a, 164b, and the third rake parts 165a, 165b, and the third rake support members 166a, 166b, are preferably made of an alloy having excellent heat resistance and corrosion resistance, such as stainless steel. The rake shaft 161b is disposed so as to be located inside the rake main shaft 161a, so it may be made of an alloy such as stainless steel, or may be made of a metal such as iron. Note that the rake shaft 161b and the rake main shaft 161a may be configured to send air taken in from outside the device into them. By configuring in this way, it is possible to expect an air-cooling effect of the rake 16 when the solid fuel is burned.

[0064] As shown in Fig. 3, the driving unit 17 is disposed below the rear surface of the combustion plate 15. The driving unit 17 is composed of an electric motor, gears, etc., in order to rotate the rake 16 around the shaft. The driving unit 17 rotates the rake 16 at a speed of, for example, about 13 seconds per revolution so that the chaff introduced onto the combustion plate 15 from the solid fuel introduction unit 12 can be discharged while the rake 16 configured as described above makes several revolutions around the combustion plate 15.

[0065] The discharge section 18 is provided outside the combustion plate body 152. The discharge section 18 forms a path for discharging the solid fuel and ash generated by combustion to the outside of the solid fuel combustion device 10. The discharge section 18 is provided to discharge the ash on the combustion table 151 collected by the third rake sections 165a, 165b to the outside of the solid fuel combustion device 10. The discharge section 18 is disposed on the moving line of the third rake sections 165a, 165b. The discharge section 18 is provided below the combustion table 151 in a front view. The opening width of the discharge section 18 is preferably about the same as the width of the third rake sections 165a, 165b. The number of the discharge sections 18 and the position in a plan view are not limited to those of this embodiment.

[0066] The air supply unit 19 takes in air taken in from outside the device into the inside of the solid fuel combustion device 10. The air supply unit 19 supplies the air taken in from the combustion air fan to the inside of the combustion chamber 14 through a hole provided in the combustion plate body 152 from the back side of the combustion plate body 152 of the combustion plate 15. For example, the air supply unit 19 is connected to the air chamber 153 of the combustion plate 15, and the air introduced from the air supply unit 19 passes through the air chamber 153 of the combustion plate 15 and is supplied to the inside of the combustion chamber 14 from the back side of the combustion plate body 152. In addition, as described above, the air introduced from the air supply unit 19 to the air chamber 153 of the combustion plate 15 may be sent into the rake shaft 161b and the rake main shaft 161a of the rake 16 via the air chamber 153, so that an air-cooling effect of the rake 16 can be expected.

[0067] Next, an example of the operation of the solid fuel combustion apparatus 10 will be described. In the solid fuel combustion apparatus 10, ignition of rice husks at the start of operation is performed by putting in fuel such as kerosene and a pilot flame. The method of igniting rice husks at the start of operation is not particularly limited.

[0068] At the start of operation of the solid fuel combustion apparatus 10, ash from rice husks that have already been introduced into the combustion chamber 14 is accumulated on the surface of the combustion plate body 152 of the combustion plate 15. In the solid fuel combustion apparatus 10, rice husks are introduced from the solid fuel introduction section 12 onto the surface near the center of the combustion plate 15. The rake 16 then rotates, for example, clockwise when viewed from a direction facing the extension direction of the rake main shaft 161a (see, for example, FIG. 4).

[0069] The chaff fed from the solid fuel introduction section 12 is burned while being stirred on the combustion plate main body 152 by the first rake sections 163a, 163b and the second rake sections 164a, 164b. Then, the first rake sections 163a, 163b and the second rake sections 164a, 164b sequentially push out some of the ash that has accumulated to a predetermined thickness or more, and move it to the outside of the combustion plate 15, that is, in the direction of the combustion table 151. Finally, the ash on the combustion plate main body 152 is discharged to the outside of the combustion plate main body 152 by the second rake sections 164a, 164b.

[0070] The third rake portions 165a and 165b rake up the ash that has been discharged outside the combustion plate body 152 and fallen onto the upper surface of the combustion table 151, and move it to the discharge portion 18. The ash moved to the discharge portion 18 is discharged to the outside of the solid fuel combustion apparatus 10.

[0071] Furthermore, in the event that a foreign object becomes mixed into the solid fuel and gets caught between the rake 16 and the combustion plate 15, the rake 16 can be raised by the lifting mechanism 168 as appropriate to allow the foreign object to escape, thereby effectively avoiding the device from stopping due to the foreign object and allowing operation to continue smoothly.

[0072] In addition to rotating the rake 16 at an arbitrary rotation speed, the solid fuel combustion device 10 can control the period during which the rice husks stay on the combustion plate 15, that is, the combustion time and accumulation amount of the rice husks, by controlling the rotation speed of the rake 16 to be synchronized with the amount of rice husks fed by the solid fuel introduction unit 12. By rotating the rake 16 at an arbitrary rotation speed, the solid fuel combustion device 10 can keep the accumulation amount and accumulation thickness (1 to 5 cm) of rice husks on the combustion plate 15 constant for the amount of rice husks supplied (7 to 60 kg / h) required for the set temperature. In addition, by providing the rake 16, the solid fuel combustion device 10 can stabilize the thickness of rice husks and ash on the combustion plate main body 152, and can appropriately manage the combustion temperature and combustion time by controlling the amount of air supply and exhaust required for combustion in accordance with the amount of rice husks supplied. The amount of air supply may be constant.

[0073] [Other embodiments] In this embodiment, the rake 16 rotates on the surface of the combustion plate 15 by the drive unit 17, but the present invention is not limited to this. For example, the rake may be fixed to an axis and the solid fuel may be stirred and moved by rotating the combustion plate.

[0074] Furthermore, the surface of the combustion plate 15 may be other than flat, for example, gently curved or slightly uneven, as long as it does not affect the combustion of the solid fuel or the stirring or movement of the solid fuel and ash by the rake 16. [Industrial Applicability]

[0075] The solid fuel combustion apparatus of the present invention is an apparatus for burning solid fuel, and for example, the heat obtained by combustion can be used for various purposes. For example, the heat obtained by burning solid fuel can be used for drying grains and other purposes, such as heating. The solid fuel combustion apparatus of the present invention can also be used in cases where the heat is not utilized, but rice husk ash is used as charcoal, that is, a soil improvement material. The above-described solid fuel combustion apparatus can also be used for biomass materials such as wood pellets and rice straw cut into lengths of 3 to 5 cm. [Explanation of symbols]

[0076] 1: Grain drying system 10: Solid fuel combustion device 11: Exterior body 12: Solid fuel introduction part 13: Hot air supply port 14: Combustion chamber 15: Burning board 16: Rake 17: Drive unit 18: Discharge section 19: Air supply section 20:Rice husk supply device 30: Grain dryer 40: Hot air supply duct 50: Blower 111: Panel 112: Frame 151: Burning stand 152: Combustion plate body 153: Air chamber 161a: Rake main shaft 161b: Rake shaft 162: Support part 163a, 163b: First rake section 164a, 164b: Second rake section 165a, 165b: 3rd rake section 166a, 166b: third rake support member 168: Lifting mechanism 168a: Camshaft 168b: Cam groove 169: Load application section

Claims

1. a combustion chamber for burning a solid fuel; a combustion plate provided in the combustion chamber and capable of placing the solid fuel to be combusted on a surface thereof; a solid fuel introduction section for introducing the solid fuel onto the combustion plate; A rake provided on the combustion plate; A drive unit that rotates at least one of the combustion plate or the rake, The solid fuel combustion device, wherein the rake has a lifting mechanism that lifts the rake to allow a foreign object to escape when the foreign object becomes caught between the rake and the combustion plate.

2. The rake has a substantially cylindrical rake main shaft and a rake shaft located inside the rake main shaft, 2. The solid fuel combustion device as described in claim 1, wherein the rake raising mechanism includes a rake main shaft, a cam shaft that slidably holds the rake shaft, and a cam groove that engages with the cam shaft provided on at least one of the rake main shaft and the rake shaft.

3. 3. The solid fuel combustion device according to claim 2, wherein the cam groove is formed inclined in a direction to convert a rotational driving force received by the rake when the foreign object is caught thereinto into a force that lifts the rake main shaft.

4. The solid fuel combustion device according to claim 2 , further comprising a load applying section that applies a vertically downward load to the camshaft.

5. The solid fuel combustion device according to claim 1 or 2, wherein the solid fuel is a biomass fuel.

6. The solid fuel combustion device according to claim 5 , wherein the solid fuel is rice husk.

Images