Patent Description:
Biomass fuel is a granular environment-friendly new energy material processed from stalks, dung of cattle and sheep, rice straw, rice husk, peanut shells, corn kernel, cottonseed shells, as well as the "three remnants". Currently, equipment for heating by burning biomass particles has been widely used.

These existing heating appliances are used by feeding biomass fuel into the furnace body through a feed hopper, where the biomass fuel is combusted in a first chamber, and the flame and some of the flue gases flow into a second chamber for complete combustion, with the flame exiting from a chimney connected to the second chamber. However, since the feed hopper is also of a certain height, it is also equivalent to a chimney. After completing the combustion of biomass fuel, there will be smoke returning to the feed hopper, which eventually leads to smoke running out from the feed hopper and polluting the environment.

<CIT> shows a gasification stove for heating air and water of living spaces comprising a containment structure which accommodates a storage tank for biomass fuel, a gasification crucible connected to an expansion chamber which in turn is connected to a combustion chamber, and an air-air heat exchanger.

In order to solve at least one of the above existing problems of the prior art, in accordance with an aspect of the present invention, provided is a biomass fuel burning furnace, including: a furnace body, provided with a first air inlet for inflowing air into the furnace body and a fuel inlet for feeding biomass fuel into the furnace body, provided with a first combustion chamber, a second combustion chamber, and a third combustion chamber sequentially communicating within the furnace body, wherein the first combustion chamber is used to receive biomass fuel conveyed from the fuel inlet for an initial combustion of the biomass fuel and a generation of flue gases, the second combustion chamber is used for a combustion of the flue gases and for a mixing of the flue gases with oxygen inflow from the first air inlet to obtain a mixture to be combusted, and the third combustion chamber is used for a combustion of the flue gases in the mixture to be combusted; a combustion guide conduit, connected to the furnace body and connected to the third combustion chamber for directing a flame resulting from the combustion of flue gases in the mixture to be combusted;.

In some implementations, the furnace body includes a housing and an enclosing frame provided within the housing;.

In some implementations, a part of the combustion guide conduit is provided within the third combustion chamber, the enclosing frame is enclosed out of the combustion guide conduit, and the second combustion chamber is formed by enclosing between the enclosing frame and the combustion guide conduit.

In some implementations, the enclosing frame includes a plurality of vertical enclosing plates and a support plate provided below the plurality of vertical enclosing plates, the vertical enclosing plate is provided with the second air inlet, and the support plate is for mounting the combustion guide conduit and is provided with the first air outlet.

In some implementations, a part of the combustion guide conduit enclosed by the vertical enclosing plate is provided with a third air inlet, and the third air inlet is in communication with the second combustion chamber.

In some implementations, a side of the enclosing frame facing the first combustion chamber is provided with a first gap, a second gap is provided in an area, corresponding to the first gap, of the combustion guide conduit, and a projected arc formed by the second gap on a reference plane in a vertical direction is at least a quarter of a projected circumference formed by the combustion guide conduit on the reference plane.

In some implementations, the combustion guide conduit includes a first section, a second section and a third section in sequence from bottom to top;.

In some implementations, a side wall of the second section is provided with a fourth air inlet, and/or a side wall of the third section is provided with a fifth air inlet.

In some implementations, a heat storage cover connected to the furnace body and covering the combustion guide conduit positioned out of the furnace body.

In some implementations, the first air inlet is provided corresponding to the third combustion chamber and the second combustion chamber, the furnace body is further provided with a main air inlet, the main air inlet is provided corresponding to the first combustion chamber, and an opening area of the main air inlet is larger than an opening area of the first air inlet.

In some implementations, a first support and a second support;.

In some implementations, a fuel-guiding shelf, provided in the first combustion chamber, is used to support the biomass fuel inputted from the fuel inlet, and is provided with an air inlet gap.

In some implementations, the fuel-guiding shelf is disposed angled upwardly in a direction distal to the second combustion chamber.

In some implementations, a sliding separator is slidably provided with respect to the fuel-input funnel and/or the furnace body to open or close the fuel inlet.

In some implementations, the fuel-input funnel includes a fuel-input section and a buffer section in sequence from top to bottom, the buffer section is connected to the first combustion chamber, and the sliding separator is slidably provided between the fuel-input section and the buffer section.

In some implementations, the sliding separator includes a barrier part and a fuel-guiding part, the barrier part is slidably provided between the fuel-input section and the buffer section for opening or closing a communicating opening, connected to the fuel-input section, of the buffer section, and the fuel-guiding part is provided angled upwardly in a direction from the furnace body to the fuel-input section.

In some implementations, a side wall of the buffer section corresponding to a sliding direction of the fuel-guiding part is disposed at an angle, and the side wall and the fuel-guiding part share a same angled direction.

In some implementations, the barrier part is provided with a fuel-input opening for being in communication with the communicating opening to open the fuel inlet by the barrier part or for crisscrossing the communicating opening to close the fuel inlet by the barrier part.

Labels: <NUM> biomass fuel burning furnace; <NUM> furnace body; <NUM> first combustion chamber; <NUM> second combustion chamber; <NUM> third combustion chamber; <NUM> first air inlet; <NUM> fuel inlet; <NUM> housing; <NUM> enclosing frame; <NUM> second air inlet; <NUM> first air outlet; <NUM> vertical enclosing plate; <NUM> support plate; <NUM> first gap; <NUM> main air inlet; <NUM> combustion guide conduit; <NUM> third air inlet; <NUM> second gap; <NUM> first section; <NUM> second section; <NUM> fourth air inlet; <NUM> third section; <NUM> fifth air inlet; <NUM> heat storage cover; <NUM> sixth air inlet; <NUM> first support; <NUM> second support; <NUM> fuel-guiding shelf; <NUM> air inlet gap; <NUM> fuel-guiding tube; <NUM> connecting tube; <NUM> adapter frame; <NUM> fuel-input funnel; <NUM> fuel-input section; <NUM> input opening; <NUM> funnel part; <NUM> guiding part; <NUM> restricting part; <NUM> third gap; <NUM> sliding slot; <NUM> inserted slot; <NUM> buffer section; <NUM> communicating opening; <NUM> angled side wall; <NUM> adjustable air inlet; <NUM> buffer part; <NUM> mounting part; <NUM> mounting plate; <NUM> insertion plate; <NUM> sliding separator; <NUM> barrier part; <NUM> fuel-input opening; <NUM> horizontal plate; <NUM> vertical plate; <NUM> fuel-guiding part; <NUM> revolving door; <NUM> retainment plate; <NUM> eighth air inlet; <NUM> lateral plate; <NUM> connecting hole; <NUM> ash receiver.

For a better understanding and implementation, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the attached drawings of the present invention.

In the description of the present invention, it is to be noted that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and other orientation or position relationships are based on the orientation or position relationships shown in the attached drawings. It is only intended to facilitate description of the present disclosure and simplify description, but not to indicate or imply that the referred device or element has a specific orientation, or is constructed and operated in a specific orientation. Therefore, they should not be construed as a limitation of the present invention.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are used only to describe specific embodiments and are not intended as a limitation of the invention.

The present disclosure is described in further detail below in conjunction with the attached drawings.

Referring to <FIG>, the biomass fuel burning furnace <NUM> provided in the embodiment of the present invention includes a furnace body <NUM> and a combustion guide conduit <NUM>.

Referring to <FIG>, a furnace body <NUM> is provided with a first air inlet <NUM> for inflowing air into the furnace body <NUM> and a fuel inlet <NUM> for feeding biomass fuel into the furnace body <NUM>. The furnace body <NUM> is provided with a first combustion chamber <NUM>, a second combustion chamber <NUM>, and a third combustion chamber <NUM> sequentially communicating within the furnace body <NUM>, in which the first combustion chamber <NUM> is used to receive biomass fuel conveyed from the fuel inlet <NUM> for an initial combustion of the biomass fuel and a generation of flue gases, the second combustion chamber <NUM> is used for a combustion of the flue gases and for a mixing of the flue gases with oxygen inflow from the first air inlet <NUM> to obtain a mixture to be combusted, and the third combustion chamber <NUM> is used for a combustion of the flue gases in the mixture to be combusted; a combustion guide conduit <NUM> is connected to the furnace body <NUM> and connected to the third combustion chamber <NUM> for directing a flame resulting from the combustion of flue gases in the mixture to be combusted; a fuel-input funnel is mounted on the furnace body <NUM> and connected to the fuel inlet <NUM> for feeding biomass fuel into the fuel inlet <NUM>, a side wall of the fuel-input funnel <NUM> being provided with an adjustable air inlet <NUM>; and a revolving door <NUM> is rotatably provided with respect to the fuel-input funnel <NUM>, and a gravity center of the revolving door <NUM> is shifted away from a rotation axis of the revolving door <NUM>, allowing for a closure of the adjustable air inlet <NUM> under a pressure of the biomass fuel, and for an opening of the adjustable air inlet <NUM> by own gravity when losing a pressure of the biomass fuel.

The biomass fuel burning furnace <NUM> mentioned above conveys the biomass fuel to the fuel inlet <NUM> through the fuel-input funnel <NUM>. Oxygen inflow through the first air inlet <NUM>. The furnace body <NUM> is configured to include three combustion chambers. The first combustion chamber <NUM> is used for the initial combustion of biomass fuel. The part that is not burned out becomes flue gas, which enters the second combustion chamber <NUM>, burns in the second combustion chamber <NUM>, and also mixes with oxygen to obtain the mixture to be combusted. The mixture to be combusted enters the third combustion chamber <NUM> to be completely combusted and the flame produced by combustion is directed upward through a range restricted by the combustion guide conduit <NUM> to be used for heating, water heating, food cooking, and so on. By providing a combustion guide conduit <NUM> with a certain length, the flue gas in the mixture to be combusted causes a chimney effect when combusting in the combustion guide conduit <NUM>, so that the hot air flow in the combustion guide conduit <NUM> creates an intensive convection, creating a negative pumping force at a lower end of the combustion guide conduit <NUM>, which contributes to the atmospheric pressure that presses the external oxygen from the first air inlet <NUM> to the furnace body <NUM>, so that the oxygen and the flue gas inside the second combustion chamber <NUM> as well as the flue gas inside the third combustion chamber <NUM> are further mixed, which contributes to the complete combustion of the flue gas and increases the speed of the flames when ejected from the combustion guide conduit <NUM>. Also, by providing a revolving door <NUM> on the fuel-input funnel <NUM> to open and close the adjustable air inlet <NUM> on the fuel-input funnel <NUM>, when the biomass fuel in the fuel-input funnel <NUM> finishes combusting, the revolving door <NUM> may automatically open by gravity, and oxygen may flow into the fuel-input funnel <NUM> through the adjustable air inlet <NUM> to break the chimney effect formed by the fuel-input funnel <NUM>, so as to avoid a phenomenon of returning smoke when the flue gas in the combustion guide conduit <NUM> is returned to the fuel-input funnel <NUM>, which contributes to the complete combustion of the flue gas in the fuel-input funnel <NUM>, and avoids the pollution of the environment by the flue gas. In such a setup, the furnace body <NUM> in the present embodiment is configured to include three combustion chambers, which achieves staged complete combustion of biomass fuels, which achieves efficient utilization of biomass fuels and avoids pollution of the environment by emitting unburnt flue gases into the air. Also, the combustion efficiency of the biomass fuel is effectively improved by providing the combustion guide conduit <NUM> to take advantage of the chimney effect.

Specifically, referring to <FIG>, the furnace body <NUM> of the present embodiment includes a housing <NUM> and an enclosing frame <NUM> provided inside the housing <NUM>. The housing <NUM> is provided with a first air inlet <NUM>. The second combustion chamber <NUM> is formed within the enclosing frame <NUM>. The enclosing frame <NUM> is provided with a second air inlet <NUM> in communication with the first combustion chamber <NUM> and a first air outlet <NUM> in communication with the third combustion chamber <NUM>. In such a setup, as the second combustion chamber <NUM> is in communication with the first air inlet <NUM> and also provided with a second air inlet <NUM> in communication with the first combustion chamber <NUM>, the flue gas produced by combustion in the first combustion chamber <NUM> enters the second combustion chamber <NUM> from the second air inlet <NUM> and mixes with the oxygen that enters the second combustion chamber <NUM> from the first air inlet <NUM> to obtain the mixture to be combusted, and also part of the flue gas is combusted in the second combustion chamber <NUM>. As the enclosing frame <NUM> is provided with a first air outlet <NUM> in communication with the third combustion chamber <NUM>, the mixture to be combusted obtained by mixing in the second combustion chamber <NUM> enters into the third combustion chamber <NUM>, and then enters into the combustion guide conduit <NUM>, and is sufficiently combusted in the third combustion chamber <NUM> and the combustion guide conduit <NUM>.

Specifically, for facilitating the setup of the second combustion chamber <NUM>, a part of the combustion guide conduit <NUM> is provided within the third combustion chamber <NUM>, and the enclosing frame <NUM> is provided outside the combustion guide conduit <NUM>, and the second combustion chamber <NUM> is formed by enclosing between the enclosing frame <NUM> and the combustion guide conduit <NUM>. In such a setup, the second combustion chamber <NUM> is formed by setting a part of the combustion guide conduit <NUM> within the third combustion chamber <NUM>, and by setting the enclosing frame <NUM> outside the combustion guide conduit <NUM>, which facilitates the setting of the second combustion chamber <NUM>. Compared with the way of designing the second combustion chamber <NUM> by the enclosing frame <NUM> itself, it is sufficient to set the enclosing frame <NUM> and the combustion guide conduit <NUM> to have a gap between them, and the second combustion chamber <NUM> is formed.

Specifically, referring to <FIG>, the enclosing frame <NUM> of the present embodiment includes four vertical enclosing plates <NUM> and a support plate <NUM> provided on a bottom of the four vertical enclosing plates <NUM>. The support plate <NUM> is provided with a first air outlet <NUM>. The vertical enclosing plates <NUM> are enclosed outside the combustion guide conduit <NUM> and provided with a second air inlet <NUM>. The support plate <NUM> is connected to the housing <NUM> and connected to the combustion guide conduit <NUM>. In such a setup, the support plate <NUM> is supported to the combustion guide conduit <NUM> and the vertical enclosing plates <NUM> to achieve the installation of both the combustion guide conduit <NUM> and the vertical enclosing plates <NUM>. A first air outlet <NUM> is provided on the support plate <NUM> to achieve being in communication with the third combustion chamber <NUM>.

It is to be understood that, in order to facilitate the inflow of oxygen from the housing <NUM> into the second combustion chamber <NUM>, a gap is provided between the vertical enclosing plates <NUM> and the housing <NUM>, though which the oxygen may inflow.

Further, in order to allow the mixture to be combusted produced in the second combustion chamber <NUM> to quickly enter the combustion guide conduit <NUM> for combustion, a part of the combustion guide conduit <NUM> enclosed by the vertical enclosing plates <NUM> is provided with a third air inlet <NUM>, and the third air inlet <NUM> is connected to the second combustion chamber <NUM>. In such a setup, the mixture to be combusted in the second combustion chamber <NUM> may directly and quickly enter into the combustion guide conduit <NUM> to allow the flue gases in the mixture to be combusted to be burned in the combustion guide conduit <NUM> and the flame to be directed out by the combustion guide conduit <NUM>, avoiding lowering the temperature of the mixture to be combusted by means of flowing from the first air outlet <NUM> through the third combustion chamber <NUM> and then into the combustion guide conduit <NUM>. Also, the particles being combusted within the second combustion chamber <NUM> flame up from the third air inlet <NUM> to contribute to the combustion of the combustible material to be combusted within the combustion guide conduit <NUM>.

Moreover, in order to facilitate the entry of the mixture to be combusted into the combustion guide conduit <NUM>, a first gap <NUM> is provided on a side of the enclosing frame <NUM> facing the first combustion chamber <NUM>, the combustion guide conduit <NUM> is provided with a second gap <NUM> in an area corresponding to the first gap <NUM>, and a projected arc formed by the second gap <NUM> on a reference plane in a vertical direction is at least a quarter of the projected circumference formed by the combustion guide conduit <NUM> on the reference plane. In such a setup, by providing a first gap <NUM> on the enclosing plates, a larger flow area is available, allowing the flue gases as well as the mixture to be combusted to flow quickly from the second combustion chamber <NUM> into the combustion guide conduit <NUM>, while the combustion guide conduit <NUM> is provided with a second gap <NUM> corresponding to the position of the first gap <NUM>. Due to the Coanda effect, the fluid has a tendency to flow with a surface of the object instead of an original flow direction. Also, since an inner wall of the combustion guide conduit <NUM> is not absolutely smooth and has protrusions, and the fluid is viscous, the flue gases, as well as the mixture to be combusted, have a tendency to flow along the inner wall of the combustion guide conduit <NUM> so as to flow along a tangential direction of the combustion guide conduit <NUM>, thereby forming a spiral upward flow pattern. Compared to the combustion mode of direct vertical upward flow along an axial direction of the combustion guide conduit <NUM>, the spiral upward flow takes a longer travel path. Since a length of the combustion guide conduit <NUM> is a certain length, the combustion time within the combustion guide conduit <NUM> is a certain period, which leads to a greater flow speed of the spiral flow of the substance to be combusted in order to provide the substance to be combusted with greater firepower for combustion, which contributes to the rapid combustion of the flue gases, as well as the substance to be combusted, within the combustion guide conduit <NUM>. Also, in conjunction with the chimney effect, a greater pumping force is generated, and air is pressed into the first air inlet <NUM> more rapidly, achieving rapid mixing of the air in the third combustion chamber <NUM> and the flue gases in the combustion guide conduit <NUM>.

It is to be understood that, in order to ensure the spiral effect of the airflow on an inner wall of the combustion guide conduit <NUM>, a projected arc formed by the second gap <NUM> on a reference plane in a vertical direction is required to be less than or equal to half of a projected circumference formed by the combustion guide conduit <NUM> on the reference plane.

Referring to <FIG>, in an embodiment of the present invention, corresponding to the aforementioned air intake structure of the furnace body <NUM>, the combustion guide conduit <NUM> includes a first section <NUM>, a second section <NUM>, and a third section <NUM> in sequence from bottom to top. The first section <NUM> is positioned in the third combustion chamber <NUM>, and a diameter of the first section <NUM> is increased gradually from bottom to top. The second section <NUM> is connected to an end of the first section <NUM> and is enclosed with the enclosing frame <NUM> to form the second combustion chamber <NUM>, the second section <NUM> is provided with a third air inlet <NUM> and a second gap <NUM>, and a diameter of the second section <NUM> is constant. A diameter of the third section <NUM> is decreased gradually from bottom to top. In such a setup, as the first section <NUM> is provided to be positioned within the third combustion chamber <NUM>, oxygen inlet is available, and setting the diameter of the first section <NUM> to be gradually increased from bottom to top, when the airflow flows from the first section <NUM> into the second section <NUM>, the airflow may be diffused and the pressure is reduced, and the diffused oxygen may promote the combustion of the flue gases within the combustion guide conduit <NUM>. By setting the diameter of the second section <NUM> to be constant and the diameter of the third section <NUM> to be gradually reduced from bottom to top, the high-pressure gas flows out of the third section <NUM>, which has a gradually reduced diameter, with a large flowing speed according to the venturi effect. Also, in conjunction with the chimney effect, the combustion guide conduit <NUM> is caused to be under negative pressure at a lower end part, which facilitates the compression of oxygen into the third combustion chamber <NUM> and the second combustion chamber <NUM>, as well as helps the rapid outflow of high-pressure gases to drive the flame from an opening of the combustion guide conduit <NUM>. In such a manner, a rapid airflow circulation is achieved, which contributes to the rapid combustion of the flue gas particles in the mixture to be combusted.

Further, referring to <FIG>, in order to ensure complete combustion of the flue gas particles within the second section <NUM> and the third section <NUM>, a side wall of the second section <NUM> is provided with a fourth air inlet <NUM>, and/or a side wall of the third section <NUM> is provided with a fifth air inlet <NUM>. By means of an air inlet also provided on the second section <NUM> and/or the third section <NUM>, it contributes to a further supply of oxygen into the second section <NUM> and/or the third section <NUM>, further contributing to a complete combustion of the flue gas particles.

Specifically, in the present embodiment, a side wall of the second section <NUM> is provided with a plurality of fourth air inlets <NUM>, and a side wall of the third section <NUM> is provided with a plurality of fifth air inlets <NUM>. The plurality of fourth air inlets <NUM> are provided in a straight line in a vertical direction, and the plurality of fifth air inlets <NUM> are provided in a circumferential array on the third section <NUM>.

Referring to <FIG>, <FIG>, and <FIG>, in the present embodiment, the first air inlet <NUM> is provided corresponding to the third combustion chamber <NUM> and the second combustion chamber <NUM>. The furnace body <NUM> is also provided with a main air inlet <NUM>, the main air inlet <NUM> is provided corresponding to the first combustion chamber <NUM>, and an opening area of the main air inlet <NUM> is larger than an opening area of the first air inlet <NUM>. In such a setup, inflow of oxygen is primarily fed through the first air inlet <NUM> to the third combustion chamber <NUM> and the second combustion chamber <NUM>, and inflow of oxygen is primarily fed through the main air inlet <NUM> to the first combustion chamber <NUM>. Since the first combustion chamber <NUM> is an area for the main combustion of the biomass fuel, by setting the main air inlet <NUM> with a larger opening area, it is possible to provide more oxygen to the first combustion chamber <NUM> quickly, avoiding the biomass fuel from having a slower combustion rate due to insufficient supply of oxygen, as well as generating too much flue gas.

Specifically, in the present embodiment, the first air inlet <NUM> is configured to be in a long-strip shape and is disposed in a horizontal direction, and the height where the first air inlet <NUM> is opened is relatively low. In such a setup, in conveying oxygen to the second combustion chamber <NUM> and the third combustion chamber <NUM> through the first air inlet <NUM>, it is avoided to result in lowering the temperature inside the second combustion chamber <NUM> and the third combustion chamber <NUM> due to the opening area of the first air inlet <NUM> being excessively large, and by providing the first air inlet <NUM> with a relatively small opening area, the flue gases inside the combustion guide conduit <NUM> may generate a negative pressure inside the combustion guide conduit <NUM> by the chimney effect when being combusted, and it is avoided that the negative pressure environment inside the combustion guide conduit <NUM> may be broken due to the opening area of the first air inlet <NUM> being relatively large.

Additionally, referring to <FIG> and <FIG>, for ensuring a high temperature environment in the combustion guide conduit <NUM>, the biomass fuel burning furnace <NUM> further includes a heat storage cover <NUM> connected to the furnace body <NUM> and covering outside of both the third section <NUM> and a part of the second section <NUM>, and the heat storage cover <NUM> is provided with a sixth air inlet <NUM> in communication with the fourth air inlet <NUM> and/or the fifth air inlet <NUM>. In such a setup, by setting the heat storage cover <NUM> outside the combustion guide conduit <NUM>, i.e., the heat storage cover <NUM> is covered outside the combustion guide conduit <NUM>, which ensures the high temperature environment in the combustion guide conduit <NUM>, allowing effective combustion of the flue gases in the combustion guide conduit <NUM>.

Specifically, in the present embodiment, when setting the sixth air inlet <NUM> outside the heat storage cover <NUM>, the sixth air inlet <NUM> is provided at an end of the heat storage cover <NUM> connected to the furnace body <NUM>, i.e., at a lower end part of the heat storage cover <NUM>, so as to allow the oxygen entering the sixth air inlet <NUM> at the lower end part to flow gradually upwardly to flow into the second section <NUM> and the third section <NUM> of the combustion guide conduit <NUM> through the fourth air inlet <NUM> and the fifth air inlet <NUM>.

It should be understood that, referring to <FIG>, <FIG>, <FIG> and <FIG>, in order to improve the combustion efficiency of the entire biomass fuel burning furnace, the biomass fuel burning furnace <NUM> further includes a first support <NUM> and a second support <NUM>. The first support <NUM> is provided on the first combustion chamber <NUM> to support a heating element for heating the biomass fuel. The second support <NUM> is provided in the third combustion chamber <NUM> and positioned below the combustion guide conduit <NUM> to support a heating element for heating the mixture to be combusted. In such a setup, by setting the first support <NUM> and the second support <NUM> to support the heating element respectively, it helps the heating element to heat the biomass fuel or the flue gases. For example, by supporting an alcohol burner or a wax block, the biomass fuel or flue gas is heated by the heat generated by the burning of the alcohol burner or the wax block, which contributes to the rapid combustion of the flue gas in the third combustion chamber <NUM>. Compared to only heating the biomass fuel individually by one heating element, two heating elements simultaneously heating the biomass fuel and the flue gases improves the combustion efficiency of the entire biomass fuel, which further contributes to the rapid combustion of the flue gas particles in the combustion guide conduit <NUM>.

Referring to <FIG>, in an embodiment of the present invention, in order to avoid an excessive accumulation of biomass fuel in the first combustion chamber <NUM> without efficiently getting heated, the biomass fuel burning furnace <NUM> further includes a fuel-guiding shelf <NUM> provided in the first combustion chamber <NUM> to support the biomass fuel inputted from the fuel inlet <NUM>, and the fuel-guiding shelf <NUM> is provided with an air inlet gap <NUM>. In such a setup, by setting the fuel-guiding shelf <NUM>, the biomass fuel entering from the fuel inlet <NUM> may be supported, and the fuel-guiding shelf <NUM> is provided with an air inlet gap <NUM> to allow the airflow to enter into the biomass fuel from the air inlet gap <NUM>, so as to avoid the accumulation of the biomass fuel resulting in a state of excessive oxygen deprivation, which leads to the inability of efficiently heating and combustion. Also, by setting the fuel-guiding shelf <NUM>, the biomass fuel is avoided from falling directly onto a bottom wall of the furnace body <NUM> after entering from the fuel inlet <NUM> and not being effectively combusted.

Specifically, the fuel-guiding shelf <NUM> in the present embodiment is provided to be positioned above the first support <NUM>, and the heating element on the first support <NUM> is positioned below the biomass fuel, so that the heating element on below heats the biomass fuel on above. The heated biomass fuel burns gradually, and the heat is transferred to the inside of the biomass fuel sequentially from bottom to top, which contributes to the combustion of the biomass fuel.

Further, referring to <FIG>, in order to allow the smoke and heat generated by the combustion of the biomass fuel in the first combustion chamber <NUM> to be quickly directed to the second combustion chamber <NUM>, the fuel-guiding shelf <NUM> is provided at an upward angle in a direction distal to the second combustion chamber <NUM>, i.e., the fuel-guiding shelf <NUM> is provided at an angle inside the first combustion chamber <NUM>, the biomass fuel enters from the fuel inlet <NUM>, and is gradually accumulated on the fuel-guiding shelf <NUM>, so that the heat and the gases are directly directed to the second combustion chamber <NUM> to allow rapid entry into the second combustion chamber <NUM> when burning takes place.

Specifically, in the present embodiment, the fuel-guiding shelf <NUM> includes a plurality of fuel-guiding tubes <NUM> and a plurality of connecting tubes <NUM>. The plurality of fuel-guiding tubes <NUM> are spaced apart, between each adjacent two fuel-guiding tubes <NUM> is the air inlet gap <NUM>, each fuel-guiding tube <NUM> is provided angled upwardly in a direction distal to the second combustion chamber <NUM>, and the plurality of connecting tubes <NUM> are connected to the fuel-guiding tubes <NUM> respectively, i.e., the fuel-guiding shelf <NUM> is provided in a form of a supporting frame formed by a plurality of tubes connected to each other, so as to allow for setting up the air inlet gap <NUM> between the tubes, so that oxygen may effectively enter into the biomass fuel positioned on above through the gaps between the tubes.

It is to be understood that, referring to <FIG>, in order to facilitate the transfer of ash generated by the combustion of the biomass fuel in the first combustion chamber <NUM>, the biomass fuel burning furnace <NUM> further includes an ash receiver <NUM>, the ash receiver <NUM> being mounted to the furnace body <NUM> in a form of a drawer, so as to facilitate the pulling out of the ash for transfer. In order to help biomass fuel inputted from the fuel inlet <NUM> to fall onto the fuel-guiding shelf <NUM>, the biomass fuel burning furnace <NUM> further includes an adapter frame <NUM>, in which the adapter frame <NUM> is connected to a side wall of the fuel inlet <NUM> to be abutted against the fuel-guiding shelf <NUM>, so as to guide biomass fuel inputted from the fuel inlet <NUM> to the fuel-guiding shelf <NUM> orderly.

Referring to <FIG> and <FIG>, in an embodiment of the present invention, in order to allow for continuous feeding of biomass fuel into the furnace body <NUM>, the biomass fuel burning furnace <NUM> further includes a fuel-input funnel <NUM> mounted on the furnace body <NUM> and in communication with the fuel inlet <NUM>. In such a setup, by setting up the fuel-input funnel <NUM>, a larger amount of biomass fuel may be input into the fuel-input funnel <NUM> all at once to temporarily store the biomass fuel through the fuel-input funnel <NUM>, and the biomass fuel within the fuel-input funnel <NUM> may slowly fall from the fuel inlet <NUM> when the biomass fuel in the first combustion chamber <NUM> is burning and gradually reduced. Also, the biomass fuel inputted from the input opening <NUM> of the fuel-input funnel <NUM> may be replenished simultaneously for continuous replenishment of the biomass fuel within the first combustion chamber <NUM> to ensure that the first combustion chamber <NUM> may be kept in a state of continuous combustion.

Further, referring to <FIG>, <FIG>, <FIG> and <FIG>, in order to facilitate control of the on-off of the biomass fuel feeding into the fuel inlet <NUM>, the biomass fuel burning furnace <NUM> further includes a sliding separator <NUM>, the sliding separator <NUM> being slidably disposed with respect to the fuel-input funnel <NUM> and/or the furnace body <NUM> to open or close the fuel inlet <NUM>, so that the fuel inlet <NUM> may be conveniently opened or closed by pushing the sliding separator <NUM> to control the on-off state of the biomass fuel entering into the fuel inlet <NUM>.

Specifically, referring to <FIG>, <FIG>, <FIG> and <FIG>, in order to avoid that the biomass fuel in the fuel-input funnel <NUM> continues to be combusted after the fuel inlet <NUM> is closed, the fuel-input funnel <NUM> includes a fuel-input section <NUM> and a buffer section <NUM> in sequence from top to bottom, and the buffer section <NUM> is connected to the first combustion chamber <NUM>, and the sliding separator <NUM> is slidably disposed between the fuel-input section <NUM> and the buffer section <NUM>, which is equivalent to the sliding separator <NUM> being disposed in a middle of the fuel-input funnel <NUM>. When the fuel inlet <NUM> is closed, there is a certain distance between the sliding separator <NUM> and the fuel inlet <NUM>, i.e., there is a certain height difference between the sliding separator <NUM> and the first combustion chamber <NUM>, so as to avoid the risk of the continued combustion of the biomass fuel in the fuel-input section <NUM> occurring due to the flames and the heat being transferred to the sliding separator <NUM>, and then from the sliding separator <NUM> to the biomass fuel in the fuel-input section <NUM> when the biomass fuel in the first combustion chamber <NUM> continues to be combusted after the fuel inlet <NUM> is closed.

Specifically, referring to <FIG>, in the present embodiment, the sliding separator <NUM> includes a barrier part <NUM> and a fuel-guiding part <NUM>, the barrier part <NUM> is slidably provided between the fuel-input section <NUM> and the buffer section <NUM> for opening or closing a communicating opening <NUM>, in communication with the fuel-input section <NUM>, of the buffer section <NUM>, and the fuel-guiding part <NUM> is provided angled upwardly in a direction from the furnace body <NUM> to the fuel-input section <NUM>. Therefore, the sliding separator <NUM> is not only provided with the barrier part <NUM> for opening or closing the fuel inlet <NUM> but also provided with an angled fuel-guiding part <NUM>. When the biomass fuel falls gradually from the fuel-input section <NUM>, as shown in <FIG>, the biomass fuel falls from the drop zone A. Due to the obstruction of the fuel-guiding part <NUM> of the sliding separator <NUM>, there is a vacant zone B positioned between a rear side of the fuel-guiding part <NUM> and a side wall of the buffer section <NUM>, and the vacant zone B is not filled with the biomass fuel. When pushing the barrier part <NUM> to slide for closing the buffer section <NUM>, the biomass fuels, which are of a certain hardness, accumulate with each other and are of high resistance to the pushing of the sliding separator <NUM>, thereby hindering the sliding of the barrier part <NUM>. By angling the fuel-guiding part <NUM> of the sliding separator <NUM> to allow the forming of the vacant zone B for releasing pressure, the fuel-guiding part <NUM> gradually moves toward the vacant zone B when the sliding separator <NUM> is gradually pulled, thereby achieving pressure relief until the barrier part <NUM> covers the buffer section <NUM>.

Further, in order to allow the biomass fuel within the buffer section <NUM> to flow to the fuel inlet <NUM>, the buffer section <NUM> is provided at an angle corresponding to a side wall of the fuel-guiding part <NUM>, and the side wall and the fuel-guiding part <NUM> share a same angled direction. For facilitating the description, the angled provided side wall is defined as the angled side wall <NUM>. In such a setup, by setting the angled side wall <NUM>, the biomass fuel is guided to gradually move toward a bottom of the fuel-guiding part <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the barrier part <NUM>, in opening and closing the buffer section <NUM>, is specified in such a way that the barrier part <NUM> is provided with a fuel-input opening <NUM> for being in communication with the communicating opening <NUM> to open the fuel inlet <NUM> by the barrier part <NUM> or for crisscrossing the communicating opening <NUM> to close the fuel inlet <NUM> by the barrier part <NUM>. In such a setup, by setting the fuel-input opening <NUM> on the barrier part <NUM>, in comparison to directly setting the entire barrier part <NUM> in a shape of a plate to open and close the fuel inlet <NUM>, when the fuel inlet <NUM> is opened or closed, it may be achieved by pulling the barrier part <NUM> to move by a relatively small distance.

Referring to <FIG>, a structural diagram of the fuel-input funnel <NUM> is shown, in which the fuel-input section <NUM> is provided with an input opening <NUM> and includes a funnel part <NUM>, a guiding part <NUM> and a restricting part <NUM>. The guiding part <NUM> is positioned on a lower end of the funnel part <NUM> and is integrated with the funnel part <NUM>. A third gap <NUM> is formed on the guiding part <NUM> in a movement direction X along the sliding separator <NUM>, and the guiding part <NUM> is inserted in the restricting part <NUM>, so that the biomass fuel entering from the funnel part <NUM> flows to the buffer section <NUM> through the guiding part <NUM> and the restricting part <NUM> in sequence, and the guiding part <NUM> is extended in a vertical direction to allow for downward guidance of the biomass fuel.

The restricting part <NUM> is provided with a sliding slot <NUM> for sliding the sliding separator <NUM>, while restricting the sliding separator <NUM> to slide in a straight line in the X direction. Specifically, in sliding relative to the restricting part <NUM>, the barrier part <NUM> includes a horizontal plate <NUM> and a vertical plate <NUM>, the horizontal plate <NUM> is provided with a fuel-input opening <NUM> for being in communication with the communicating opening <NUM>, and the vertical plate <NUM> is used to slide along the restricting part <NUM> in the sliding slot <NUM>, so as to drive the crossing and overlapping between the fuel-input opening <NUM> and the communicating opening <NUM> of the buffer section <NUM>, so as to achieve the closure and opening of the fuel inlet <NUM> of the furnace body <NUM>.

Further, for facilitating mounting of the fuel-input section <NUM> and the sliding separator <NUM>, the buffer section <NUM> includes a buffer part <NUM> and a mounting part <NUM> disposed at a top of the buffer part <NUM>, in which the mounting part <NUM> is provided with a communicating opening <NUM>, and the mounting part <NUM> includes a mounting plate <NUM> and an insertion plate <NUM>, with the mounting plate <NUM> disposed in a horizontal direction, and the insertion plate <NUM> disposed in a vertical direction. When mounting the fuel-input section <NUM> and the sliding separator <NUM>, the restricting part <NUM> of the fuel-input section <NUM> is provided with an insertion slot <NUM>, and the insertion plate <NUM> is inserted into the insertion slot <NUM>, while the horizontal plate <NUM> of the sliding separator <NUM> is slid along the mounting plate <NUM> and the restricting part <NUM>, so as to achieve the closure and opening of the fuel inlet <NUM> of the furnace body <NUM>.

In such a setup, by setting a third gap <NUM> on a side of the guiding part <NUM> along the movement direction X, when the sliding separator <NUM> is slid along the X direction to perform a closure of the fuel inlet <NUM>, the biomass fuel within the fuel-input section <NUM> may gradually move along the third gap <NUM> under the support of the horizontal plate <NUM>, so as to achieve for a slow release of the pressure, and to avoid an excessive resistance to the movement of the sliding separator <NUM> due to the accumulated biomass fuel when the sliding separator <NUM> is being pulled.

Referring to <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, in an embodiment of the present invention, in order to avoid any return of smoke from the combustion guide conduit <NUM>, the biomass fuel burning furnace <NUM> further includes a revolving door <NUM>, the fuel-guiding part <NUM> is provided with an adjustable air inlet <NUM>, the revolving door <NUM> is rotatably provided with respect to the fuel-guiding part <NUM>, and a gravity center of the revolving door <NUM> is shifted away from a rotation axis of the revolving door <NUM>, allowing for a closure of the adjustable air inlet <NUM> under the gravity of the biomass fuel, and for an opening of the adjustable air inlet <NUM> by the own gravity when the biomass fuel finishes combustion. In such a setup, when combustion of the biomass fuel is required, the biomass fuel enters the buffer section <NUM> from the fuel-input section <NUM>, and then enters the first combustion chamber <NUM> from the buffer section <NUM>. The biomass fuel gradually falls and is accumulated in the buffer section <NUM>, and applies pressure to the revolving door <NUM> to press the revolving door <NUM> against the adjustable air inlet <NUM> to achieve the closure of the adjustable air inlet <NUM>. When the buffer section <NUM> is closed by sliding the retainment plate <NUM>, the biomass fuel positioned in the buffer section <NUM> gradually falls into the first combustion chamber <NUM> to gradually complete combustion, at which time the revolving door <NUM> loses the compression of the biomass fuel and is able to be rotated, and since the gravity center of the revolving door <NUM> is shifted away from the rotation axis of the revolving door <NUM>, the revolving door <NUM> is rotated along its own rotating axis to open the adjustable air inlet <NUM>. In this case, the adjustable air inlet <NUM> allows air to enter, avoiding a vacuum state in the buffer section <NUM> when the biomass fuel in the buffer section <NUM> completes combustion, which results in the flue gases in the second combustion chamber <NUM> and the third combustion chamber <NUM> returning to the buffer section <NUM>, and thus results in the biomass fuel not being completely combusted.

Specifically, referring to <FIG>, the rotating center of the revolving door <NUM> is b, the gravity center of the revolving door <NUM> is a, and they are not positioned on the same line.

Specifically, referring to <FIG>, the revolving door <NUM> includes a retainment plate <NUM> and two lateral plates <NUM> provided on two opposite sides of the retainment plate <NUM>. Two lateral plates <NUM> are provided with connecting holes <NUM> through which a rotating shaft is provided to open and close the adjustable air inlet <NUM> by means of the retainment plate <NUM>.

It is to be understood that, since the gravity center of the revolving door <NUM> and the center of the rotating shaft deviate from each other, the center of the entire revolving door <NUM> in the present embodiment is positioned on the retainment plate <NUM>, but the center of the rotating shaft is positioned on the connecting center of the two connecting holes <NUM>. In such a setup, when the biomass fuel in the buffer section <NUM> is burned out, the revolving door <NUM> is rotated around the rotating axis so as to disengage the adjustable air inlet <NUM> in order to achieve the opening of the adjustable air inlet <NUM>, thereby avoiding the return of smoke in the buffer section <NUM>.

Further, after the biomass fuel in the buffer section <NUM> finishes combustion, in order to allow more rapid entry of air into the buffer section <NUM>, the retainment plate <NUM> may be provided with an eighth air inlet <NUM>, so that the air entering from the adjustable air inlet <NUM> may also flow rapidly from the eighth air inlet <NUM> into the buffer section <NUM>.

In the biomass fuel burning furnace <NUM> mentioned above, the furnace body <NUM> is configured to include the first combustion chamber <NUM>, the second combustion chamber <NUM>, and the third combustion chamber <NUM>. The first combustion chamber <NUM> is used for the initial combustion of biomass fuel. The flue gas particles mix with oxygen in the second combustion chamber <NUM> to obtain the mixture to be combusted. The flue gases in the mixture to be combusted enter the third combustion chamber <NUM> to be completely combusted and the flame produced by combustion is directed rapidly through the combustion guide conduit <NUM>. The furnace body <NUM> is further provided with a fuel-input funnel <NUM> to continuously convey biomass fuel to the furnace body, which ensures the first combustion chamber <NUM> to be in a state of continuous combustion. The fuel-input funnel <NUM> is configured to include the fuel-input section <NUM>, the buffer section <NUM>, and the sliding separator <NUM>, in which the sliding separator <NUM> closes or opens the fuel inlet <NUM>, which prevents spontaneous combustion of the biomass fuel above the sliding separator <NUM> after the sliding separator <NUM> closes against the fuel inlet <NUM>. The buffer section <NUM> is configured with the revolving door <NUM> and the adjustable air inlet <NUM>, so that the revolving door <NUM> is capable of opening and closing the adjustable air inlet <NUM> to avoid the presence of flue gases flowing from the combustion guide conduit <NUM> in the buffer section <NUM>, i.e., avoid the phenomenon of returning flue gases.

In summary, the biomass fuel burning furnace provided in the present invention has technical effects as follows:
The biomass fuel is conveyed through the fuel inlet. Oxygen inflow through the first air inlet. The furnace body is configured to include three combustion chambers. The first combustion chamber is used for the initial combustion of biomass fuel. The part that is not burned out becomes flue gas, which enters the second combustion chamber, burns in the second combustion chamber, and also mixes with oxygen to obtain the mixture to be combusted. The mixture to be combusted enters the third combustion chamber to be completely combusted and the flame produced by combustion is directed upward through a range restricted by the combustion guide conduit to be used for heating, water heating, food cooking, and so on. By providing a combustion guide conduit with a certain length, the flue gas in the mixture to be combusted causes a chimney effect when being combusted in the combustion guide conduit, so that the hot air flow in the combustion guide conduit creates an intensive convection, creating a negative pumping force at a lower end of the combustion guide conduit, which contributes to the atmospheric pressure that presses the external oxygen from the first air inlet to the furnace body, so that the oxygen and the flue gas inside the second combustion chamber, as well as the flue gas inside the third combustion chamber, are further mixed, which contributes to the complete combustion of the flue gas and increases the speed of the flames when ejected from the combustion guide conduit. Also, by providing a revolving door on the fuel-input funnel to open and close the adjustable air inlet on the fuel-input funnel, when the biomass fuel in the fuel-input funnel finishes being combusted, the revolving door may automatically open by gravity, and oxygen may flow into the fuel-input funnel through the adjustable air inlet to break the chimney effect formed by the fuel-input funnel, so as to avoid the phenomenon of returning smoke when the flue gas in the combustion guide conduit is returned to the fuel-input funnel, which contributes to the complete combustion of the flue gas in the fuel-input funnel, and avoids the pollution of the environment by the flue gas.

Claim 1:
A biomass fuel burning furnace (<NUM>), comprising:
a furnace body (<NUM>), provided with a first air inlet (<NUM>) for inflowing air into the furnace body (<NUM>) and a fuel inlet (<NUM>) for feeding biomass fuel into the furnace body (<NUM>), provided with a first combustion chamber (<NUM>), a second combustion chamber (<NUM>), and a third combustion chamber (<NUM>) sequentially communicating within the furnace body (<NUM>), wherein the first combustion chamber (<NUM>) is used to receive biomass fuel conveyed from the fuel inlet (<NUM>) for an initial combustion of the biomass fuel and a generation of flue gases, the second combustion chamber (<NUM>) is used for a combustion of the flue gases and for a mixing of the flue gases with oxygen inflow from the first air inlet (<NUM>) to obtain a mixture to be combusted, and the third combustion chamber (<NUM>) is used for a combustion of the flue gases in the mixture to be combusted;
a combustion guide conduit (<NUM>), connected to the furnace body (<NUM>) and connected to the third combustion chamber (<NUM>) for directing a flame resulting from the combustion of flue gases in the mixture to be combusted;
a fuel-input funnel (<NUM>), mounted on the furnace body (<NUM>) and connected to the fuel inlet (<NUM>) for feeding biomass fuel into the fuel inlet (<NUM>), a side wall of the fuel-input funnel (<NUM>) being provided with an adjustable air inlet (<NUM>); and
a revolving door (<NUM>), rotatably provided with respect to the fuel-input funnel (<NUM>), and a gravity center of the revolving door (<NUM>) being shifted away from a rotation axis of the revolving door (<NUM>), allowing for a closure of the adjustable air inlet (<NUM>) under a pressure of the biomass fuel, and for an opening of the adjustable air inlet (<NUM>) by own gravity when losing a pressure of the biomass fuel.