Full-premixing burner

Abstract

The invention discloses a full-premixing burner which comprises an air shell, an ignition flame stabilizing needle is further arranged in the air shell, and the full-premixing burner further comprises a nozzle fixed to the head end of the air shell and used for allowing high-speed fuel gas to enter; the injection pipe is located in the air shell, is arranged to be a Venturi pipe and is used for fully and uniformly mixing fuel gas and air, an inlet of the injection pipe is connected with an outlet of the nozzle, an outlet of the injection pipe is connected with a burner head, and the ignition flame stabilizing needle is used for igniting an ignition hole in the burner head; the secondary air inlet is formed in the side part of the air shell and is communicated with the interior of the air shell; and the short fire protection cylinder is fixed at the tail end of the air shell and is used for spraying ignited flames to a hearth. Thus, after the fuel gas and the air are fully and uniformly mixed, the fuel gas and the air are mixed with the secondary air and combusted at the same time, the combustion heat efficiency is improved, the consumption of the fuel gas is reduced, the emission amount of waste gas such as CO, CO2 and NOX is reduced, and low-nitrogen emission is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of burners, and in particular to a full premixed burner. Background Art

[0002] At present, in the field of industrial kilns, most of the combustion devices are diffusion combustion methods and a small number of them adopt semi-premixed combustion methods. Among them, (1) the diffusion industrial combustion method mainly adopts the gas interface to spray gas through the burner fixed seat and the inner cavity of the burner core, and then the secondary air blown in by the power fan is mixed inside the burner air shell by the burner head, and it is mixed while burning after ignition. Its primary air coefficient α is less than 0 (no primary air); (2) the atmospheric combustion method mainly adopts the gas interface to spray gas and air through the burner fixed seat and the inner cavity of the burner core for partial premixing in advance, and the secondary air blown in by the power fan is mixed again inside the burner air shell by the burner head, and finally released by the ignition needle to release high voltage electricity to ignite, and it is mixed while burning. Its primary air coefficient α has a value range of: 0<α<1.

[0003] Therefore, no matter whether it is the primary air sucked in by high-speed fuel gas injection through the air door or the primary air forced in by a power blower, the primary air coefficient (set to α) is in the range of 0<α<1 in the above two combustion methods. In order to achieve a sufficiently high combustion thermal efficiency, secondary air must be provided, that is, excess air must be added. When too much excess air is added, the consumption of fuel gas and the generation of a large amount of harmful waste gases such as CO, CO2, NOX, etc. will increase.

[0004] The disadvantages of the above two combustion methods are: (1) low thermal efficiency; (2) increased gas consumption and the generation of large amounts of harmful waste gases such as CO, CO2, NOX, etc., which in turn cause pollution. Summary of the invention

[0005] In order to solve the technical problems existing in the background technology, the present invention proposes a full premixed burner.

[0006] The present invention provides a fully premixed burner, comprising an air housing, an ignition flame stabilizing needle disposed inside the air housing, and further comprising:

[0007] A nozzle, fixed at the head end of the air housing, for high-speed combustion gas to enter;

[0008] The ejector tube is located in the air housing and is configured as a venturi tube for fully and evenly mixing the gas and the air. The inlet of the ejector tube is connected to the outlet of the nozzle, and the outlet is connected to the burner head. The ignition flame stabilizing needle is used to ignite the ignition hole of the burner head.

[0009] A secondary air inlet, located at a side of the air housing and communicating with the interior of the air housing;

[0010] A short flame protection tube is fixed at the rear end of the air shell and is used for spraying the ignited flame into the furnace.

[0011] Preferably, the nozzle includes an inlet section, a middle section and an outlet section connected thereto, the inlet section is set as a tapered inlet with a front diameter greater than a rear diameter, the outlet section is set as a tapered outlet with a front diameter less than a rear diameter, the rear diameter of the tapered inlet is equal to the front diameter of the tapered outlet, and the cross-sectional area of ​​the middle section is equal from front to back.

[0012] Preferably, the included angle of the conical inlet is set to 105° to 120°, and the included angle of the conical outlet is set to 30° to 60°.

[0013] Preferably, the venturi tube comprises:

[0014] A contraction tube connected to the conical outlet;

[0015] Mixing tube, used to mix gas and air;

[0016] The outlet end of the diffuser pipe is connected to the burner head through a fixing sleeve.

[0017] Preferably, there are multiple ignition holes, the diameter of the ignition hole close to the ignition needle is set to 4-5 mm, and the diameter of the other ignition holes is 1.5-2.0 mm.

[0018] Preferably, the shape of the burner head is set to be a concave arc-shaped honeycomb mesh body.

[0019] Preferably, the number of the ignition holes is set to 150-180, and the ignition flame-stabilizing needle ignites the first ignition hole and transmits the ignition to all ignition holes in the entire burner head to form a conical fire ring.

[0020] Preferably, the burner head is formed by one-step firing of ceramics.

[0021] Preferably, the system further comprises a blower, wherein the blower is used to blow the secondary air into the system through the secondary air inlet.

[0022] In summary, the present invention has the following beneficial effects: the gas is injected into the nozzle at high speed and pressure, and the surrounding air is sucked in through the air gate, and then enters the ejector tube of the burner. When the mixed gas enters the ejector tube, since the ejector tube adopts a Venturi structure, the gas enters the mixing tube at a super high speed after passing through the contraction tube of the ejector tube, and the air molecules and the gas molecules collide with each other. At this time, the primary air and the gas are highly evenly mixed. After the mixed gas / air mixture is ejected through the ignition hole at a certain high speed, it is mixed again with the secondary air (combustion-supporting air). The first ignition hole is ignited by the ignition flame stabilizing needle, and the flame is transmitted to all the ignition holes of the entire burner head through the first ignition hole to form a conical fire ring, and finally the flame is ejected to the furnace through the short fire protection tube. In this way, after the gas and air are fully mixed, they are mixed with the secondary air while burning, which improves the combustion thermal efficiency, reduces the consumption of gas, and reduces the emission of waste gases such as CO, CO2, and NOX, and achieves low nitrogen emissions.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a full premixed burner according to an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of the structure of a nozzle according to an embodiment of the present invention;

[0026] Figure 3 For the embodiment of the present invention Figure 1 Left view of

[0027] Figure 4 A front view of a burner head according to an embodiment of the present invention;

[0028] Figure 5 It is a side view of a burner head according to an embodiment of the present invention.

[0029] In the figure:

[0030] 1. Air shell; 2. Ignition flame stabilizing needle; 3. Nozzle; 31. Inlet section; 32. Middle section; 33. Outlet section; 4. Ejector tube; 41. Contraction tube; 42. Mixing tube; 43. Diffuser; 5. Burner head; 6. Fixed sleeve; 7. Secondary air inlet; 8. Short fire protection tube; 9. Ignition hole; 10. Air outlet; 11. Silicone sealing ring; 13. Metal sleeve. DETAILED DESCRIPTION

[0031] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0032] like Figure 1-5 As shown, a full premix burner proposed in this embodiment includes an air housing 1, an ignition flame stabilizing needle 2 is also provided inside the air housing, and also includes:

[0033] The nozzle 3 is fixed to the head end of the air housing 1;

[0034] The ejector tube 4 is located in the air housing 1 and is set as a venturi tube, and is used to fully and evenly mix the gas and the air. The inlet of the ejector tube 4 is connected to the outlet of the nozzle 3, and the outlet is connected to the burner head 5. The ignition flame stabilizing needle 2 is used to ignite the ignition hole 9 of the burner head 5;

[0035] A secondary air inlet 7 is located at a side of the air housing 1 and communicates with the interior of the air housing 1;

[0036] The air conditioner also includes a blower, which is used to blow the secondary air into the air through the secondary air inlet 7.

[0037] The short flame shield 8 is fixed to the rear end of the air shell 1 and is used to spray the ignited flame into the furnace.

[0038] In this way, the gas is injected into the nozzle 3 at high speed and pressure, and the surrounding air is sucked in through the air gate 10 (located on both sides of the nozzle 3) and enters the ejector tube 4 of the burner. When the mixed gas enters the ejector tube 4, since the ejector tube 4 adopts a Venturi structure, the gas enters the mixing tube 42 at a super high speed after passing through the contraction tube 41 of the ejector tube 4, and the air molecules and the gas molecules collide with each other. At this time, the primary air and the gas are highly evenly mixed. After the mixed gas / air mixture is ejected through the ignition hole 9 at a certain high speed, it is mixed again with the secondary air (combustion-supporting air). The first ignition hole is ignited by the ignition flame stabilizing needle 2, and the flame is transmitted to all the ignition holes 9 of the entire burner head 5 through the first ignition hole, and finally the flame is ejected to the furnace through the short flame protection tube 8. In this way, after the gas and air are fully mixed, they are mixed with the secondary air while burning, which improves the combustion thermal efficiency, reduces the gas consumption, and reduces the emission of exhaust gases such as CO, CO2, and NOX, achieving low nitrogen emissions.

[0039] Furthermore, if Figure 2As shown, the nozzle 3 includes an inlet section 31, a middle section 32 and an outlet section 33 connected thereto, the inlet section 31 is set as a tapered inlet with a front diameter larger than a rear diameter, the outlet section 33 is set as a tapered outlet with a front diameter smaller than a rear diameter, the rear diameter of the tapered inlet is equal to the front diameter of the tapered outlet, and the cross-sectional area of ​​the middle section 32 is equal from front to back.

[0040] Furthermore, due to the input high-speed gas pressure, the gas moves into the nozzle 3 in the high-speed airflow, the angle of the conical inlet is set to 105°~120°, the angle of the conical outlet is set to 30°~60°, the gas flow velocity at the conical inlet is low, and the gas flow velocity at the conical outlet is high, which can make the pressure of the primary air and gas (mixed gas) obtain a higher injection velocity again.

[0041] In this embodiment, Figure 1 As shown, the venturi tube 4 comprises:

[0042] The shrink tube 41 is connected to the conical outlet;

[0043] A mixing tube 42, used for mixing gas and air;

[0044] The outlet end of the diffuser tube 43 is connected to the burner head 5 through the fixing sleeve 6 .

[0045] When the mixed gas enters the ejector tube 4, since the ejector tube 3 adopts a Venturi structure, the fuel gas enters the mixing tube 42 at an extremely high speed after passing through the contraction tube 41 of the ejector tube 4, and the air molecules and the fuel gas molecules collide with each other. At this time, the air and the fuel gas are highly evenly mixed, and finally ejected through the diffuser tube of the ejector tube 4 to the ignition holes 9 of the burner head 5.

[0046] Preferably, if Figure 4 As shown, there are multiple ignition holes 9, and the diameter of the ignition hole close to the ignition flame stabilizing needle 2 is set to 4-5mm, which is conducive to improving the ignition rate and the ignition flame stabilizing needle needle head completely contacts the flame to maintain the normal operation of the burner; the diameter of other ignition holes is 1.5-2.0mm. Specifically, the number of ignition holes is set to 150-180, and the ignition flame stabilizing needle 2 ignites the first ignition hole, which is transmitted to all ignition holes in the entire burner head 5 to form a conical fire ring. The primary air coefficient can reach 1.02-1.05, the flame ejection speed can reach: 15-20m / s, the ejection flame length is short, the combustion thermal efficiency is as high as over 90%, the power: 10-40kW, the adjustment ratio range: 3:1-12:1, the applicable gas types: natural gas, liquefied petroleum gas, methane, propane, butane, coke oven gas, etc., the maximum furnace temperature is ≤1500℃, the air inlet pressure is: 300-500Pa, the air inlet pressure is: <700Pa, NOX≤5ppm, and it has excellent technical performance.

[0047] It should be noted that if Figure 5 As shown, the shape of the burner head 5 is set to be a concave arc-shaped honeycomb mesh body. Specifically, the burner head 5 is set to be formed by ceramic firing in one step. The temperature resistance can be as high as 1500°C or above. Furthermore, a metal sleeve 12 is also configured on one side of the burner head 5 where the ignition hole 9 is provided, which can not only protect the burner head 5 from external impact, but also, since the burner head 5 is made of ceramic material, there will be thermal expansion and contraction, and the metal sleeve 12 can prevent the burner head 5 from deformation.

[0048] It should be noted that the nozzle 3 in this embodiment is made of HPb59-1 (lead brass), which has the advantages of high temperature resistance of more than 800°C, high corrosion resistance, good mechanical strength, excellent processing and cutting performance, high processing qualification rate, and low cost.

[0049] The venturi tube 4 can be made of JYH21CT stainless steel (also known as 443 stainless steel), which has the characteristics of low carbon, low nitrogen, nickel-free, molybdenum-free, high chromium, high corrosion resistance, good thermal conductivity, and low thermal expansion coefficient, and is known as green and environmentally friendly stainless steel.

[0050] The burner head 5 is made of SUS316 stainless steel, which has the advantages of high temperature resistance above 1600℃ and high corrosion resistance. The ignition flame stabilizing needle is made of chromium-nickel alloy steel wire + 95 ceramic composite material.

[0051] The air housing 1 is machined from a SUS316 stainless steel pipe.

[0052] The short fire shield 8 is made of silicon carbide and has a high temperature resistance of over 1600°C.

[0053] Among them: the nozzle 3 and the conical spring are fixed in the burner fixing seat assembly through threaded connection. The burner fixing seat assembly and the air shell 1 are connected by 4 SUS304 stainless steel hardened heat-treated M4*10 countersunk screws. The burner fixing seat assembly and the air shell 1 are easy to assemble, easy to disassemble and repair, and replace the wearing parts such as the sealing ring. The burner fixing seat assembly and the burner core (Venturi tube and burner head) are formed into one body by seamless full welding process to ensure that it has sufficient mechanical strength. The seal of the burner fixing seat assembly and the air shell 1 is provided with a silicone sealing ring 11 to ensure that it has excellent sealing and high corrosion resistance such as strong acid and alkali. The tail of the ignition flame stabilizing needle 2 is designed with a thread and the tail end is fixed to the burner fixing seat assembly with a hexagonal nut. The needle head ceramic body of the ignition flame stabilizing needle 2 is designed with 3 circles of concave annular rings, and a 65Mn spring steel sheet retaining ring is used to fix it on the flame stabilizing disk. Considering the ignition rate performance, the ignition distance between the ignition flame-stabilizing needle 2 and the ignition hole 9 (i.e., the hypotenuse distance of the right triangle) must be controlled within 3-4 mm.

[0054] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0056] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0058] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A full premix burner, comprising an air housing, an ignition flame stabilizing needle is provided inside the housing, characterized in that: Also includes: A nozzle, fixed at the head end of the air housing, for high-speed combustion gas to enter; The ejector tube is located in the air housing and is configured as a venturi tube for fully and evenly mixing the gas and the air. The inlet of the ejector tube is connected to the outlet of the nozzle, and the outlet is connected to the burner head. The ignition flame stabilizing needle is used to ignite the ignition hole of the burner head. A secondary air inlet, located at a side of the air housing and communicating with the interior of the air housing; A short flame protection tube is fixed at the rear end of the air shell and is used for spraying the ignited flame into the furnace.

2. The full premix burner according to claim 1, characterized in that: The nozzle includes an inlet section, a middle section and an outlet section connected thereto, the inlet section is set as a tapered inlet with a front diameter larger than a rear diameter, the outlet section is set as a tapered outlet with a front diameter smaller than a rear diameter, the rear diameter of the tapered inlet is equal to the front diameter of the tapered outlet, and the cross-sectional area of ​​the middle section is equal from front to back.

3. The full premix burner according to claim 2, characterized in that: The included angle of the conical inlet is set to 105° to 120°, and the included angle of the conical outlet is set to 30° to 60°.

4. The full premix burner according to claim 1, characterized in that: The venturi tube comprises: A contraction tube connected to the conical outlet; Mixing tube, used for mixing gas and air; The outlet end of the diffuser pipe is connected to the burner head through a fixing sleeve.

5. The full premix burner according to claim 1, characterized in that: There are multiple ignition holes, the diameter of the ignition hole close to the ignition needle is set to 4-5 mm, and the diameter of the other ignition holes is 1.5-2.0 mm.

6. The full premix burner according to claim 1, characterized in that: The shape of the burner head is set to be a concave arc-shaped honeycomb mesh body.

7. The full premix burner according to claim 5, characterized in that: The number of the ignition holes is set to 150-180. The ignition flame stabilizing needle ignites the first ignition hole and transmits the ignition to all the ignition holes in the entire burner head to form a conical fire ring.

8. The full premix burner according to claim 6, characterized in that: The burner head is formed by one-step firing of ceramics.

9. The full premix burner according to claim 5, characterized in that: Also included is a blower for blowing secondary air through the secondary air inlet.

Images