Full-premixing efficient semi-radiation gas stove with regenerative air pre-heater heat shield

Abstract

The invention discloses a full-premixing efficient semi-radiation gas stove with a regenerative air pre-heater heat shield, and relates to the technical field of gas equipment. The gas inlet device comprises a gas inlet shell, an outer ring radiation cooking range is installed in the gas inlet shell, and an inner ring convection cooking range assembly is arranged in the outer ring radiation cooking range. According to the invention, a heat insulation hearth air preheater structure is adopted, high-temperature flue gas heat is recovered to preheat air, and a combined structure of a fan and a full-premixing ejector is adopted, so that the pressure difference between two ends of an air nozzle is increased, the ejection capacity of fuel gas to air is improved, full-premixing ejection and stability of a variable-load air-fuel ratio are realized, and the energy consumption is reduced. A combined structure of the inner-ring convection cooking range and the outer-ring radiation cooking range is adopted, the radiation heat transfer capacity of the gas stove is greatly enhanced, meanwhile, the convective heat transfer and open fire characteristics of the inner-ring cooking range are reserved, high-temperature flue gas generated by the inner-ring cooking range and high-temperature flue gas generated by the outer-ring radiation cooking range are converged, and the heat transfer efficiency of the gas stove is improved. And the wall-attached jet heat transfer capability of high-temperature flue gas of the outer ring radiation cooking range to the pot bottom is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas equipment, and particularly relates to a fully premixed high-efficiency semi-radiant gas stove with a recuperative air preheater heat shield. Background Art

[0002] Currently, the mainstream gas stoves on the market are atmospheric gas stoves, which adopt semi-premixed combustion. That is, the gas stove ejector uses the gas pressure head to eject part of the air, and the air coefficient is 30% - 70% of the theoretical air volume. The semi-premixed gas after ejection is ejected through the holes of the burner head and burns, and the insufficient air (secondary air) is supplemented through the environment. Therefore, atmospheric gas stoves are all of an open structure (to facilitate the supplement of secondary air); and the high-temperature flame formed by combustion mainly exchanges heat with the bottom of the pot in a convective manner, resulting in the thermal efficiency of atmospheric gas stoves being concentrated between 53% - 65%, and it is very difficult to significantly improve the thermal efficiency. The ways of heat loss include the direct thermal radiation of the high-temperature flame to the environment and the bottom surface of the burner head, and at the same time, a large amount of heat is discharged with the flue gas. In addition, the outer flame surface of semi-premixed combustion is a diffusion flame surface, and there will be situations of local uneven combustion and incomplete combustion. The flame surface temperature is not as high as that of fully premixed combustion, the burnout degree is incomplete, a small amount of CO and NOx are generated, and at the same time, the flame temperature decreases due to incomplete combustion and heat dissipation to the environment, which limits the heat transfer ability of the flame to the cookware. With the deepening of energy conservation, emission reduction and low-carbon emission policies, it has become extremely urgent to improve the thermal efficiency of household gas stoves.

[0003] In addition, the infrared radiation gas stoves on the market mainly use porous ceramic burner head materials coated with high emissivity. The porous structure can divide the semi-premixed gas into countless small airflows, which burn on the surface or in the holes of the pores, keeping the porous burner head at a relatively high temperature. The solid porous burner head conducts radiative heat transfer to the cookware at high temperature, greatly improving the radiative heat transfer efficiency of the gas stove. However, the flat flame results in a short flame, and the convective scouring heat transfer ability of the high-temperature flame to the bottom of the pot is reduced. The overall thermal efficiency has been improved compared with the mainstream open convection stoves, but because people are more accustomed to gas stoves with visible flames and the phenomenon of the flame wrapping the pot, the acceptance of infrared radiation stoves is relatively low.

[0004] Fully premixed combustion has the advantages of high combustion heat intensity, fast combustion speed, high and uniform flame temperature, high burnout rate and low pollutant emissions. However, fully premixed combustion requires pre-mixing the gas and the required combustion air before combustion, and at the same time, the flow rate of the premixed gas can change proportionally with the change of the operating load of the gas stove, and the air-fuel ratio of the premixed gas can also be maintained stable; the ejectors of the existing atmospheric gas stoves on the market cannot meet this requirement. In addition, the fully premixed burner has flashback and blow-off phenomena, and its combustion stability is worse than that of atmospheric (semi-premixed) type.

[0005] Therefore, we provide a fully premixed high-efficiency semi-radiant gas stove with a recuperative air preheater heat shield to solve the above problems. Summary of the Invention

[0006] The object of the present invention is to provide a fully premixed high-efficiency semi-radiation gas stove with a recuperative air preheater heat shield. Through the cooperation of the inner-ring convective burner assembly, the fully premixed injector assembly, and the heat shield air preheater assembly, the problems of flashback and blowout existing in the fully premixed burner in the prior art, and its combustion stability being lower than that of the atmospheric burner are solved.

[0007] To solve the above technical problems, the present invention is realized through the following technical solutions.

[0008] The present invention is a fully premixed high-efficiency semi-radiation gas stove with a recuperative air preheater heat shield, including an air inlet housing. An outer-ring radiation burner is installed inside the air inlet housing, and an inner-ring convective burner assembly is arranged inside the outer-ring radiation burner to increase the stability of the flame through the inner-ring convective burner assembly; a fully premixed injector assembly is installed at the bottom of the air inlet housing. The fully premixed injector assembly includes an air inlet pipe connected to the bottom of the air inlet housing, a diffuser pipe connected to the air inlet pipe, a throat pipe connected to one end of the diffuser pipe, a hot air chamber connected to the throat pipe, and a gas nozzle installed inside the hot air chamber to adjust the air volume and air pressure through the fully premixed injector assembly; a heat shield air preheater assembly is arranged on the surface of the air inlet housing. The heat shield air preheater assembly includes a heat shield body installed on the surface of the air inlet housing, a vacuum chamber and an air chamber opened inside the heat shield body to absorb the heat of the flue gas in the flue to preheat the air through the heat shield air preheater assembly.

[0009] The present invention is further configured such that the fully premixed injector assembly further includes a hot air pipe connected to the bottom of the heat shield body, an air valve opened on the surface of the hot air pipe, and the outlet of the hot air pipe is connected to the side wall of the hot air chamber of the injector.

[0010] The present invention is further configured such that the hot air chamber is a tapered pipe structure, a gas nozzle is sleeved along the axis inside, the outlet of the gas nozzle is located at the minimum cross-section of the hot air chamber, the outlet of the hot air chamber is connected to the throat pipe, and the outlet of the throat pipe is a diffuser pipe, and the diffuser pipe is a tapered expansion pipe structure.

[0011] The present invention is further configured such that the heat shield air preheater assembly further includes a cold air inlet pipe, and the other end of the cold air inlet pipe is connected to a blower The present invention is further configured such that the outer-ring radiation burner is made of cordierite and porous ceramic materials, and straight holes are uniformly opened inside.

[0012] The present invention is further configured such that the inner-ring convective burner assembly includes a burner housing installed inside the outer-ring radiation burner, and an upper burner hole and a side burner hole opened inside the burner housing.

[0013] The present invention is further configured such that the aperture of the side burner hole is larger than that of the upper burner hole, and the surface of the burner head shell is made of copper material.

[0014] The present invention is further configured such that the height of the outer ring radiant burner head is higher than that of the inner ring convection burner head assembly, and an infrared radiation coating is applied inside the outer ring radiant burner head.

[0015] The present invention is further configured such that an air duct baffle is installed inside the air cavity for adjusting the air flow direction.

[0016] The present invention is further configured such that the hot air cavity, the throat pipe, and the diffuser pipe form a Venturi tube, and the inlet section of the Venturi tube is a flared reduced opening.

[0017] The present invention has the following beneficial effects.

[0018] 1. By adopting the structure of the heat-insulating furnace chamber air preheater, the present invention recovers the radiant heat dissipated by the high-temperature flue gas to the environment to preheat the air, obtains the combustion-required air with a temperature higher than the ambient temperature, adopts the combined structure of a fan and a fully premixed injector, increases the pressure difference at both ends of the air nozzle, improves the injector capacity of the gas to the air, realizes the stability of fully premixed injection and variable-load air-fuel ratio, adopts the combined structure of the inner ring convection burner head and the outer ring radiant burner head, greatly enhances the radiant heat transfer capacity of the gas stove, and at the same time retains the convective heat transfer and open flame characteristics of the inner ring burner head. The confluence of the high-temperature flue gas generated by the inner ring burner head and the high-temperature flue gas generated by the outer ring radiant burner head strengthens the wall-attached jet heat transfer capacity of the high-temperature flue gas of the outer ring radiant burner head to the bottom of the pot.

[0019] 2. The present invention greatly improves the combustion efficiency of the gas by adopting the fully premixed combustion method, reduces the generation of CO and NOx; the heat-insulating furnace chamber air preheater changes the open furnace structure into a closed heat-insulating structure, and by recovering the heat dissipation of the high-temperature flame, the intake temperature of the premixed gas is increased, thereby improving the ignition performance and stable combustion characteristics of the gas, at the same time increasing the flame temperature, strengthening the heat exchange between the flame and the cookware, and the radiant burner head increases the radiant heat exchange area and radiant heat exchange capacity of the burner head, effectively improving the thermal efficiency of the gas stove.

[0020] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments will be briefly introduced below.

[0022] Figure 1 It is a three-dimensional view of a fully premixed high-efficiency semi-radiant gas stove with a regenerative air preheater heat shield.

[0023] Figure 2Full-premix high-efficiency semi-radiant gas stove with recuperative air preheater heat shield Figure 1 Bottom view.

[0024] Figure 3 Cross-sectional view of the structure of a full-premix high-efficiency semi-radiant gas stove with recuperative air preheater heat shield

[0025] Figure 4 Cross-sectional view of the diffuser tube, throat tube and gas nozzle in a full-premix high-efficiency semi-radiant gas stove with recuperative air preheater heat shield

[0026] Figure 5 Cross-sectional view of the burner head shell in a full-premix high-efficiency semi-radiant gas stove with recuperative air preheater heat shield

[0027] Figure 6 Separation schematic diagram of the intake housing and the outer-ring radiant burner head in a full-premix high-efficiency semi-radiant gas stove with recuperative air preheater heat shield

[0028] Figure 7 Cross-sectional view of the heat shield body and the hot air duct in a full-premix high-efficiency semi-radiant gas stove with recuperative air preheater heat shield

[0029] Figure 8 Side view of the heat shield body in a full-premix high-efficiency semi-radiant gas stove with recuperative air preheater heat shield

[0030] In the attached drawings: 1. Intake housing; 2. Outer-ring radiant burner head; 3. Inner-ring convection burner head assembly; 4. Full-premix injector assembly; 401. Inlet pipe; 406. Hot air chamber; 403. Gas nozzle; 405. Throat tube; 402. Diffuser tube; 5. Heat shield air preheater assembly; 501. Heat shield body; 502. Vacuum chamber; 503. Air chamber; 404. Hot air duct; 407. Air valve; 504. Cold air inlet pipe; 301. Burner head shell; 302. Upper burner hole; 303. Side burner hole; 6. Air duct baffle. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be described in conjunction with the attached drawings in the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Embodiment

[0032] Please refer to Figures 1-8, the present invention is a fully premixed high-efficiency semi-radiation gas stove with a recuperative air preheater heat shield, including an intake housing 1. An outer-ring radiation burner 2 is installed inside the intake housing 1, and an inner-ring convection burner assembly 3 is arranged inside the outer-ring radiation burner 2 to increase the stability of the flame through the inner-ring convection burner assembly 3. A fully premixed ejector assembly 4 is installed at the bottom of the intake housing 1. The fully premixed ejector assembly 4 includes an intake pipe 401 connected to the bottom of the intake housing 1, a diffuser pipe 402 connected to one end of the intake pipe 401, a throat pipe 405 connected to the diffuser pipe, a hot air chamber 406 connected to the other end of the throat pipe 405, and a gas nozzle 403 installed inside the hot air chamber 406. The air volume and air pressure are adjusted through a fan and the fully premixed ejector assembly 4. An air preheater heat shield assembly 5 is arranged on the surface of the intake housing 1. The air preheater heat shield assembly 5 includes a heat shield body 501 installed on the surface of the intake housing 1, a vacuum chamber 502 and an air chamber 503 opened inside the heat shield body 501. The heat of the flue gas in the flue is absorbed by the air preheater heat shield assembly 5 to preheat the air.

[0033] Specifically: The air preheater heat shield assembly 5 is a double-layer cavity structure. The upper air chamber 503 is an air flow passage. The cold air is provided by a fan and sent into the air chamber 503 through the cold air intake pipe 504 on the lower surface of the heat shield body 501. The cold air absorbs the heat from the furnace chamber and the flue in the cavity of the heat shield body 501. The preheated air flows out from the hot air pipe 404 on the lower surface of the heat shield body 501 and is sent into the fully premixed ejector assembly 4. There is an air duct baffle inside the air chamber 503 at the cold air inlet and the hot air outlet of the heat shield body 501, which plays a role in adjusting the wind direction. The lower cavity of the heat shield body 501 is a vacuum chamber 502, which plays an adiabatic and heat preservation role. The upper surface of the heat shield body 501 and the bottom of the pot form a flue, and the heat of the flue gas in the flue is absorbed to preheat the air. The lower inner wall surface of the heat shield body 501 is the inner wall surface of the furnace chamber, which absorbs the radiant heat of the high-temperature flame to preheat the air. The lower surface and the outer wall surface of the heat shield body 501 are in contact with the environment. Due to the vacuum interlayer, the heat dissipation to the environment is isolated. The material of the heat shield body 501 is a metal material. Embodiment

[0034] Please refer to Figures 1-8, on the basis of Embodiment 1, the fully premixed injector assembly 4 further includes a hot air pipe 404 connected to the bottom of the heat insulation cover body 501, an air valve 407 opened on the surface of the hot air pipe 404, a hot air cavity 406 connected to the hot air pipe 404, a gas nozzle 403 sleeved inside the hot air cavity 406, the other end of the hot air cavity 406 is a throat pipe 405, the outlet of the throat pipe 405 is a diffuser pipe 402, and the diffuser pipe 402 is connected to the air inlet pipe 401. The inside of the vacuum cavity 502 is in a vacuum state. The heat insulation cover air preheater assembly 5 further includes a cold air inlet pipe 504, and the other end of the cold air inlet pipe 504 is connected to a fan. The outer ring radiant burner head 2 is made of cordierite and porous ceramic materials, and is uniformly provided with straight holes inside. The inner ring convection burner head assembly 3 includes a burner head shell 301 installed inside the outer ring radiant burner head 2, an upper burner hole 302 and a side burner hole 303 opened inside the burner head shell 301.

[0035] Specifically: The fully premixed injector assembly 4 adopts a Venturi tube plus gas nozzle 403 structure. The inlet section of the Venturi tube is a flared reduced opening, which is also an air nozzle. The hot air coming out of the heat insulation cover air preheater assembly 5 enters the air nozzle in the reduced opening section of the Venturi tube, reduces pressure and increases speed, and flows into the throat pipe 405. A gas nozzle 403 is arranged on the central axis of the reduced opening section of the Venturi tube, and the nozzle outlet is located at the inlet position of the throat pipe 405 of the Venturi tube. The gas is depressurized and accelerated through the nozzle and forms a low-pressure environment at the position of the throat pipe 405 at the nozzle outlet. The hot air coming out of the heat insulation cover air preheater assembly 5 has a certain pressure. Under the action of the pressure difference between the inlet and outlet of the air nozzle, it is entrained into the Venturi tube, reduces pressure and increases speed, and flows into the throat pipe 405 to mix with the gas at the outlet of the gas nozzle 403. The mixed premixed gas flows out after being depressurized and accelerated through the flared section of the Venturi tube. The difference between the fully premixed injector assembly 4 and the existing atmospheric injector is that the air entering the injector is hot air. In addition, the hot air has a certain wind pressure (the reason is that the cold air is sent by a fan and preheated in the air preheater, and the outlet head is higher than the ambient pressure). Because the pressure difference between the inlet and outlet of the air nozzle is higher than that of the atmospheric type, the entrained air volume increases, realizing the full premixed injection of gas into air. The air inlet section of the fully premixed injector assembly 4 is connected to the heat insulation cover body 501 through the hot air pipe 404, and there is a damper on the connecting air pipe to adjust the air volume and wind pressure. Embodiment

[0036] Please refer to Figures 1-8 , on the basis of Embodiment 1 and Embodiment 2, the aperture of the side burner hole 303 is larger than that of the upper burner hole 302. The surface of the burner head shell 301 is made of copper material. The height of the outer ring radiant burner head 2 is higher than that of the inner ring convection burner head assembly 3. The inside of the outer ring radiant burner head 2 is coated with an infrared radiation coating. An air duct baffle 6 is installed inside the air cavity 503 to adjust the air flow direction. The hot air cavity 406, the throat pipe 405 and the diffuser pipe 402 form a Venturi tube, and the inlet section 406 of the Venturi tube is a flared reduced opening.

[0037] Specifically, there are two to three rows of upper burner holes 302 on the upper surface of the burner housing 301. The side wall of the burner housing 301 is composed of multiple rows of side burner holes 303. The diameters of the two rows of staggered burner holes are slightly smaller than those of the atmospheric burner holes, and the large and small holes are staggered, which increases the stability of the flame. The surface of the burner housing 301 is made of copper material to enhance the heat transfer of the burner wall surface. The outer ring radiant burner 2 is made of porous ceramic materials such as cordierite, has a certain thickness, and is evenly distributed with multiple rows of straight holes inside. The aperture of the holes is small. The surface of the radiant burner and the internal pores of the cordierite are coated with an infrared radiation coating to enhance the radiation characteristics of the radiant burner. The arrangement height of the outer ring radiant burner 2 is slightly higher than that of the burner housing 301. mainly because the combustion of the outer ring radiant burner 2 mostly occurs inside or on the surface of the burner holes, forming a planar flame with a relatively small flame height, which is significantly shorter than the flame height of the convection burner. Therefore, the distance between the surface of the radiant burner and the bottom of the pot should not be too large, and there is an optimal distance. The air inlet cavity is arranged on the lower surface of the inner and outer burners, and the lower end of the air inlet pipe is connected to the outlet of the fully premixed ejector assembly 4, which plays a role in shunting and premixing the gas.

[0038] The working principle of the present invention is as follows: The blower provides all the air required for combustion. The fully premixed ejector assembly 4 is composed of a Venturi tube and a gas nozzle 403. The gas nozzle 403 is arranged in the air inlet pipe section of the Venturi tube. The gas is depressurized and accelerated by the nozzle, forming a low-pressure environment in the throat of the Venturi tube, so that there is a pressure difference between the inlet and outlet of the air inlet section (the trumpet-shaped constriction section) of the Venturi tube. Air is entrained and sucked into the Venturi tube, and after being depressurized and accelerated by the air nozzle in the constriction section, it flows into the throat 405 and mixes with the gas. Since the air is sent by the blower and has a certain head before entering the Venturi tube, this increases the pressure difference between the two ends of the constriction section (the air nozzle) of the Venturi tube, which is conducive to entraining more air, thereby realizing the full premixed entrainment of gas by air. When the gas stove operates at variable load, the inlet head and flow rate of the gas nozzle 403 decrease simultaneously. Adjusting the frequency of the blower and the air inlet valve can also change the air volume and air pressure to achieve a stable air-fuel ratio entrainment under variable combustion load.

[0039] At the same time, the gas stove adopts an insulated furnace chamber structure with an insulated cover 501. The insulated furnace chamber absorbs the radiant heat of the high-temperature flame on the furnace chamber wall and preheats the cold air sent by the blower. The insulated cover 501 is a double-layer cavity structure. The upper air cavity 503 is an air flow channel. The cold air is provided by the blower and sent into the air cavity 503 from the cold air inlet pipe 504 on the lower surface of the insulated cover 501. Inside the cavity of the insulated cover 501, it absorbs the heat from the furnace chamber and the flue, and the preheated air flows out from the hot air pipe 404 on the lower surface of the insulated cover 501 and is sent into the fully premixed ejector assembly 4 to mix with the gas, which improves the initial temperature and ignition performance of the premixed gas, increases the flame temperature at the same time, enhances the heat transfer between the flame and the bottom of the pot, and isolates the radiant heat dissipation of the flame to the environment, reducing the heat dissipation loss.

[0040] Only certain exemplary embodiments of the present invention have been described by way of illustration. Without doubt, for those of ordinary skill in the art, the described embodiments can be modified in various different ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A fully premixed high-efficiency semi-radiation gas stove with a recuperative air preheater heat shield, including an air inlet housing (1), characterized in that, An outer ring radiant burner head (2) is installed inside the intake housing (1), and an inner ring convection burner head assembly (3) is arranged inside the outer ring radiant burner head (2) to increase the stability of the flame; A fully premixed ejector assembly (4) is installed at the bottom of the intake housing (1). The fully premixed ejector assembly (4) includes an intake pipe (401) connected to the bottom of the intake housing (1), a diffuser pipe (402) connected to one end of the intake pipe (401), a throat pipe (405) connected to the diffuser pipe (402), and a hot air pipe (406) connected to the throat pipe (405). A gas nozzle (403) is installed inside the hot air pipe (406) to adjust the air volume and air pressure through the fully premixed ejector assembly (4); An insulated hood air preheater assembly (5) is arranged on the surface of the intake housing (1). The insulated hood air preheater assembly (5) includes an insulated hood body (501) installed on the surface of the intake housing (1), a vacuum chamber (502) and an air chamber (503) opened inside the insulated hood body (501), and the insulated hood air preheater assembly (5) absorbs the heat of the flue gas in the flue to preheat the air; 2. The fully premixed high-efficiency semi-radiation gas stove with a recuperative air preheater heat insulation cover according to claim 1, wherein: The fully premixed ejector assembly (4) further includes a hot air pipe (404) connected to the bottom of the insulated hood body (501), an air valve (407) on the hot air pipe (404), and an intake pipe (401) connected between the diffuser pipe (402) and the intake housing (1); 3. The all-premix high-efficiency semi-radiation gas stove with a recuperative air preheater heat shield according to claim 2, characterized in that: The other end of the hot air pipe (404) is communicated with the hot air chamber (406), and the inside of the vacuum chamber (502) is in a vacuum state; 4. The fully premixed high-efficiency semi-radiation gas stove with a recuperative air preheater heat shield according to claim 1, characterized in that: The insulated hood air preheater assembly (5) further includes a cold air intake pipe (504), and the other end of the cold air intake pipe (504) is communicated with a blower; 5. The fully premixed high-efficiency semi-radiation gas stove with a recuperative air preheater heat shield according to claim 1, characterized in that: The outer ring radiant burner head (2) is made of cordierite and porous ceramic materials, and straight holes are uniformly opened inside; 6. The all-premix high-efficiency semi-radiation gas stove with a recuperative air preheater heat shield according to claim 1, wherein: The inner ring convection burner head assembly (3) includes a burner head shell (301) installed inside the outer ring radiant burner head (2), an upper burner hole (302) and a side burner hole (303) opened inside the burner head shell (301); 7. The fully premixed high-efficiency semi-radiation gas stove with a recuperative air preheater heat insulation cover according to claim 6, characterized in that: The aperture of the side burner hole (303) is larger than that of the upper burner hole (302), and the surface of the burner head shell (301) is made of copper material; 8. The all-premixed high-efficiency semi-radiation gas stove with a recuperative air preheater heat shield according to claim 1, characterized in that: The height of the outer ring radiant burner head (2) is higher than that of the inner ring convection burner head assembly (3), and an infrared radiation coating is applied inside the outer ring radiant burner head (2); 9. The fully premixed high-efficiency semi-radiation gas stove with a recuperative air preheater heat insulation cover according to claim 1, characterized in that: An air duct baffle (6) is installed inside the air chamber (503) to adjust the air flow direction; 10. The fully premixed high-efficiency semi-radiation gas stove with a recuperative air preheater heat shield according to claim 1, characterized in that: The hot air chamber (406), the throat pipe (405) and the diffuser pipe (401) form a Venturi tube, and the hot air chamber (406) at the inlet section of the Venturi tube is in a shape of a flared necking.

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