Direct-fired hot air furnace

Abstract

The utility model discloses a direct combustion hot -blast stove belongs to hot -blast stove technical field, including combustion cavity, the combustion cavity one side is connected with total air supply pipe, the combustion cavity other side is connected with hot -blast mixing chamber, the outlet of hot -blast mixing chamber is connected with double hot -blast pass through hot -blast switching output assembly intercommunication, be provided with flame observation window on the combustion cavity outer wall. The utility model can realize hot -blast stove combustion stability, and the heat flow distribution is adjustable.

Description

Technical Field

[0001] This utility model belongs to the field of hot blast stove technology, specifically relating to a direct-fired hot blast stove. Background Technology

[0002] Currently, the drying of nuts (such as peanuts, sunflower seeds, walnuts, almonds, etc.) mostly uses hot air furnaces to provide high-temperature hot air, gradually removing the moisture inside the nuts to extend shelf life and improve flavor. However, existing direct-fired hot air furnaces suffer from unstable combustion during the nut drying process. Most direct-fired hot air furnaces use a single-chamber combustion structure, which is greatly affected by fluctuations in gas pressure and air volume. The flame is prone to drift or incomplete combustion, leading to fluctuations in hot air temperature. Nuts are sensitive to drying temperature, and unstable temperature can cause some nuts to char while the inside remains uncooked. The hot air outlets of existing devices are mostly fixed channels, which cannot flexibly adjust the heat supply for different stages of the nut drying process (such as preheating, dehydration, and shaping). This can easily lead to insufficient or excessive heat at certain stages, affecting the uniformity of drying and flavor quality of the nuts. Traditional hot air furnaces lack effective airflow rectification measures between the combustion chamber and the outlet, resulting in localized high-temperature and low-temperature zones in the hot air. This causes uneven heating of the nuts in different areas, easily leading to "dry outside and wet inside" or "partially over-roasted" conditions.

[0003] Therefore, a direct-fired hot air furnace with more stable combustion, uniform airflow, and the ability to achieve multi-path distribution of hot air is needed to meet the requirements of temperature stability and hot air uniformity in the nut drying process. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a direct-fired hot air furnace that can achieve stable combustion and adjustable heat flow distribution.

[0005] The technical solution adopted by this utility model is a direct-fired hot air furnace, including a combustion chamber, a main air supply pipe connected to one side of the combustion chamber, a hot air mixing chamber connected to the other side of the combustion chamber, the outlet of the hot air mixing chamber being connected to a dual hot air passage through a hot air switching output component, and a flame observation window provided on the outer wall of the combustion chamber.

[0006] The present invention is further characterized in that, The combustion chamber is divided into an ignition chamber, a main combustion chamber, and a flame stabilization chamber from left to right. The ignition chamber is equipped with an igniter and an oxygen-supporting nozzle. The main combustion chamber is equipped with a main gas nozzle and an annular oxygen-supporting disc. The flame stabilization chamber is equipped with a swirl guide vane and a porous flame stabilization disc from left to right. The cavity between the swirl guide vane and the porous flame stabilization disc is an expansion section, i.e., a recirculation zone.

[0007] Both the oxygen-aiding nozzle and the annular oxygen-aiding disc are connected to the main air supply pipe.

[0008] The hot air mixing chamber is equipped with a flow guide and rectifier grid. The hot air switching output component includes a distribution rotary valve, and a fan-shaped valve plate is symmetrically connected to the outer center of the distribution rotary valve.

[0009] The dual hot air passages include a preheating section air passage and a main drying section air passage.

[0010] The beneficial effects of this utility model are: (1) This utility model provides a direct-fired hot air furnace with a combustion chamber consisting of a three-section structure: an ignition chamber, a main combustion chamber, and a flame stabilization chamber. The ignition chamber is equipped with an igniter and an oxygen-supporting nozzle. The main combustion chamber is supplied with oxygen by a main gas nozzle and an annular oxygen-supporting disc. The flame stabilization chamber is equipped with swirling guide vanes and a porous flame stabilization disc, forming a recirculation zone, which effectively suppresses flame drift and backfire, and improves combustion stability and efficiency.

[0011] (2) This utility model provides a direct-fired hot air furnace that, through the structural design of the distribution rotary valve and the fan-shaped valve plate, can switch the hot air to different hot air paths, realize differentiated air supply between the preheating section and the main drying section, and meet the drying needs of different stages. Attached Figure Description

[0012] Figure 1 This is a structural diagram of a direct-fired hot air furnace according to this utility model; Figure 2 This is a cross-sectional view of a direct-fired hot air furnace according to this utility model; Figure 3 This is a structural diagram of a hot air switching output component in a direct-fired hot air furnace according to this utility model.

[0013] In the diagram, 1. Combustion chamber, 101. Ignition chamber, 102. Main combustion chamber, 103. Flame stabilization chamber, 104. Igniter, 105. Oxygen-supporting nozzle, 106. Main gas nozzle, 107. Annular oxygen-supporting disc, 108. Swirl guide vane, 109. Perforated flame stabilization disc, 110. Recirculation zone, 2. Main air supply duct, 3. Hot air mixing chamber, 301. Flow guide and rectifier grid, 4. Hot air switching output assembly, 401. Distribution rotary valve, 402. Sector valve plate, 5. Dual hot air passages, 501. Preheating section air passage, 502. Main drying section air passage, 6. Flame observation window. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model. Example 1:

[0015] like Figure 1-3 As shown, this utility model discloses a direct-fired hot air furnace, including a combustion chamber 1. One side of the combustion chamber 1 is connected to a main air supply pipe 2 for providing combustion-supporting gas flow to ensure air supply during combustion. The other side of the combustion chamber 1 is connected to a hot air mixing chamber 3 for receiving the high-temperature airflow formed after combustion and rectifying and homogenizing it. The outlet end of the hot air mixing chamber 3 is connected to a dual hot air passage 5 through a hot air switching output component 4, which can selectively deliver hot air to the preheating section or the main drying section according to different working conditions, realizing differentiated heating for different drying stages. A flame observation window 6 is provided on the outer wall of the combustion chamber 1, which facilitates the operator to monitor the combustion status and flame shape in real time, thereby ensuring the safety and stability of operation.

[0016] The combustion chamber 1 is divided into an ignition chamber 101, a main combustion chamber 102, and a flame stabilization chamber 103 from left to right. Each chamber has a clearly defined functional area and is tightly connected to the others. The ignition chamber 101 is equipped with an igniter 104 and an oxygen-supporting nozzle 105 to provide an initial ignition source and a stable air supply during the start-up phase, ensuring that the combustion gas can be successfully ignited and quickly form a flame. The main combustion chamber 102 is equipped with a main combustion gas nozzle 106 and an annular oxygen-supporting disc 107. The main combustion gas nozzle 106 is used to inject the main combustion gas, while the annular oxygen-supporting disc 107 is arranged around the nozzle to provide uniform combustion. Combustion air is provided to ensure that the flame burns fully in the main combustion chamber 102, releasing a large amount of heat energy. The flame stabilizing chamber 103 is provided with a swirl guide vane 108 and a porous flame stabilizing disk 109 arranged from left to right. The swirl guide vane 108 is used to generate rotational motion of the airflow, and the porous flame stabilizing disk 109 is used to disperse the flame and stabilize the combustion state. The cavity between the two forms an expansion section, namely the recirculation zone 110, which can guide some of the high-temperature flue gas back to the front end of the combustion, thereby improving the stability and completeness of combustion, avoiding flame backfire and extinction, and ensuring the continuity, efficiency and safety of the overall combustion process.

[0017] Both the oxygen-supporting nozzle 105 and the annular oxygen-supporting disk 107 are connected to the main air supply pipe 2. The main air supply pipe 2 serves as a unified air supply channel, continuously supplying air into the combustion chamber 1 via a blower. The oxygen-supporting nozzle 105 is arranged in the ignition chamber 101 to provide a local high concentration of combustion-supporting air in the initial stage of ignition, enabling the gas to be quickly ignited and burn stably. The annular oxygen-supporting disk 107 is located in the main combustion chamber 102 and is distributed in a ring around the main gas nozzle 106. After being connected to the main air supply pipe 2, it can evenly spray the supplied air around the flame to form a uniform air curtain layer, thereby promoting the full mixing of gas and air and improving combustion efficiency. Through this dual-path air supply method, the different requirements for air volume and air distribution in the ignition and main combustion stages can be met respectively, realizing the step-by-step enhancement and stable control of the combustion process, ensuring more complete overall combustion and a more stable flame.

[0018] The hot air mixing chamber 3 is provided with a flow guide and rectifier grid 301. The flow guide and rectifier grid 301 is arranged along the hot air flow direction. The grid structure can disperse and rectify the air flow after the high temperature air flow enters the mixing chamber, so that the turbulent air flow is transformed into a uniform flow field, thereby avoiding the generation of local high temperature zones and ensuring that the distribution of hot air in the subsequent channels is more balanced. The hot air switching output component 4 includes a distribution rotary valve 401, and a sector valve plate 402 is symmetrically connected to the outer center of the distribution rotary valve 401. The sector valve plate 402 can rotate around the central axis of the distribution rotary valve 401 under the drive of the actuator. Different angles correspond to different opening areas, so as to realize the selection and distribution of dual hot air passages.

[0019] The dual hot air passage 5 includes a preheating section air passage 501 and a main drying section air passage 502. The preheating section air passage 501 is used to deliver hot air at a lower temperature before the material enters the drying process, so as to slowly heat up the material and avoid surface hardening or cracking due to sudden heating, thereby ensuring the stability of subsequent drying. The main drying section air passage 502 corresponds to the main drying area and is used to deliver hot air at a higher temperature and with a larger air volume to fully heat and evaporate the moisture of the preheated material. Through this dual hot air passage setup, the drying process can be segmented and precise, so that the hot air furnace can meet the differentiated requirements of temperature and air volume at different process stages, and improve the overall thermal efficiency and drying quality.

[0020] Working principle: When the hot blast stove is started, the blower provides a continuous and stable supply of air to the combustion chamber 1 through the main air supply pipe 2. The igniter 104 in the ignition chamber 101 ignites the gas, while the oxygen-supporting nozzle 105 injects local air to ensure rapid flame formation and stable combustion. The main gas nozzle 106 in the main combustion chamber 102 injects gas, and the annular oxygen-supporting disk 107 supplies oxygen evenly to the periphery of the flame, so that the gas and air are fully mixed and a high-temperature flame is generated. The swirling guide vanes 108 in the flame stabilizing chamber 103 rotate the airflow, and the porous flame stabilizing disk 109 disperses and stabilizes the flame. The expansion section recirculation zone 110 guides some of the high-temperature gas back, further enhancing the stability and completeness of combustion. The high-temperature gas flow generated after combustion enters the hot air mixing chamber 3. Under the action of the flow guide and rectifier grid 301, the airflow is homogenized, avoiding local high-temperature zones. The homogenized hot air enters the dual hot air passage 5. The distribution rotary valve 401, driven by the actuator, drives the sector valve plate 402 to rotate, thereby selectively distributing the hot air to the preheating section air passage 501 or the main drying section air passage 502 in the dual hot air passage 5. The preheating section air passage 501 is used to provide the material with lower temperature hot air to achieve slow heating; the main drying section air passage 502 is used to provide the material with high temperature and large volume hot air to accelerate moisture evaporation. Through the above process, the entire device achieves the synergistic effect of zoned combustion, flame stabilization control, airflow homogenization, and branched air supply, ensuring the stability, uniformity, and adaptability of hot air output, thereby improving the material drying efficiency and quality.

[0021] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A direct-fired hot air furnace, characterized in that, It includes a combustion chamber (1), a main air supply pipe (2) connected to one side of the combustion chamber (1), a hot air mixing chamber (3) connected to the other side of the combustion chamber (1), the outlet of the hot air mixing chamber (3) is connected to a dual hot air passage (5) through a hot air switching output component (4), and a flame observation window (6) is provided on the outer wall of the combustion chamber (1).

2. The direct-fired hot blast stove according to claim 1, characterized in that, The combustion chamber (1) is divided into an ignition chamber (101), a main combustion chamber (102), and a flame stabilization chamber (103) from left to right. An igniter (104) and an oxygen-supporting nozzle (105) are provided in the ignition chamber (101). A main gas nozzle (106) and an annular oxygen-supporting disc (107) are provided in the main combustion chamber (102). A swirl guide vane (108) and a porous flame stabilization disc (109) are provided in the flame stabilization chamber (103) from left to right. The cavity between the swirl guide vane (108) and the porous flame stabilization disc (109) is an expansion section, namely the recirculation zone (110).

3. A direct-fired hot blast stove according to claim 2, characterized in that, Both the oxygen-aiding nozzle (105) and the annular oxygen-aiding disc (107) are connected to the main air supply pipe (2).

4. A direct-fired hot blast stove according to claim 3, characterized in that, The hot air mixing chamber (3) is provided with a flow guide and rectifier grid (301). The hot air switching output component (4) includes a distribution rotary valve (401), and a fan-shaped valve plate (402) is symmetrically connected to the outer center of the distribution rotary valve (401).

5. A direct-fired hot blast stove according to claim 4, characterized in that, The dual hot air passage (5) includes a preheating section air passage (501) and a main drying section air passage (502).

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