CN108844068B - Full-premix surface type burner gas-air blender - Google Patents

Abstract

A fully premixed surface burner gas-air blender, which belongs to the technical field of combustion equipment. The invention is intended to solve the problem that traditional burners are difficult to achieve uniform mixing of gas and air, and the burners are prone to backfire, have low combustion efficiency, and have low levels of pollutant gas emissions. high question. The Venturi annular gas chamber is located in the gas and air premixing chamber and is coaxially arranged. One end of the main gas pipe is fixed on the gas and air premixing chamber through a fixed flange, and the other end passes through the gas and air premixing chamber and is connected to the Venturi annular gas chamber. There is an inner air duct in the Venturi annular gas chamber, and an outer air duct is provided between the Venturi annular gas chamber and the gas air premixing chamber. The two ends of the Venturi annular gas chamber are respectively equipped with upstream swirl blades and downstream The swirl blades, the upstream swirl blades and the downstream swirl blades are all provided with an included angle with the axial direction. The fully premixed surface burner gas-air blender of the present invention can fully mix air and gas, and finally achieve uniform mixing of gas and air through swirl blades.

Description

A fully premixed surface burner gas air blender

Technical field

The invention relates to a fully premixed surface burner gas-air blender and belongs to the technical field of combustion equipment.

Background technique

Most of the gas-air mixing structures used in existing premixed burners are very simple, and it is difficult to achieve the effect of uniform mixing of gas and air. Therefore, the burner is prone to backfire, the combustion efficiency is low, and the pollutant gas emissions are high.

The following three blending structural forms are common technical forms. Examples of typical structures are given as follows:

1. Swirl blade/mixing wheel type

Patent number: CN105546533A

A plurality of gas nozzles and a plurality of swirl blades are arranged at the rear end of the gas pipe; the gas enters the throat evenly through the nozzle holes on the gas nozzle gun and the gas pipe holes on the gas pipe; at the same time, the combustion air and the The gas is mixed evenly in the throat, and then is further mixed evenly by the swirling blades installed at the end of the gas pipe. The mixing distance is shortened, which effectively avoids uneven flame temperature due to uneven mixing of the gas, thus reducing NOx. emission.

Disadvantages: It has a mixing dead zone, and the closer it is to the inner wall of the throat, the more uneven the gas/air concentration components will be.

2. Venturi structure

Patent number: WO2012007823A1

A venturi channel type air/gas mixer is positioned downstream of the fan with respect to the air flow (AF). The mixer includes a local pressure loss device, in this case consisting of a venturi duct tube. The air/gas ratio is mainly adjusted by adjusting the nozzle size (UGL) (UG2), followed by the adjustment of the flow regulator. A flow regulator placed on the connecting pipe between the gas valve and the venturi channel type air/gas mixer allows precise adjustment of the supplied gas volume to have an optimal air/gas ratio for mixed combustion in the combustion head .

Disadvantages: The characteristic size of the flow channel is reduced, the flow rate changes, and the air side pressure suddenly increases, resulting in a significant pressure difference between gas/air, and insufficient gas injection, resulting in uneven radial mixing of gas/air.

3. Orifice plate/wire mesh structure

Patent number: US6834504B2

The swirl generator has an axially extending, at least approximately rotationally symmetrical chamber, with combustion flowing through an inlet slit preferably parallel to the longitudinal axis. As a result of the tangential orientation of these more or less slit-shaped inlets, the combustion air experiences a strong tangential velocity component, causing interaction with an axial component towards the burner mouth or outlet to swirl through the internal chamber . Enrichment of the fuel is optionally or complementarily carried out by means on the housing hood in the vicinity of the combustion air inlet slit and/or via a central feed in the burner axis. A mesh structure is arranged in the downstream portion of the burner within the mixing portion of the combustion air with the fuel. The mesh structure consists of at least one wire mesh spanning the flow cross-section.

Disadvantages: The main function of the mesh structure is to enhance the turbulence of the mixed gas after passing through the mesh structure, thereby enhancing the mixing. However, the gaps in the mesh structure are very small, which will cause greater resistance to the flow.

Contents of the invention

The object of the present invention is to provide a fully premixed surface burner gas-air blender to solve the above problems.

A fully premixed surface burner gas air mixer includes a gas air premixing chamber, an upstream swirl blade, a downstream swirl blade, a Venturi annular gas cavity, a main gas pipe, an inner air duct, an outer air duct and a fixed flange;

The Venturi annular gas chamber is located in the gas and air premixing chamber and is coaxially arranged. One end of the main gas pipe is fixed on the gas and air premixing chamber through a fixed flange, and the other end passes through the gas and air premixing chamber and is connected to the Venturi annular gas chamber. There is an inner air duct in the Venturi annular gas chamber, and an outer air duct is provided between the Venturi annular gas chamber and the gas air premixing chamber. The two ends of the Venturi annular gas chamber are respectively equipped with upstream swirl blades and downstream The swirl blades, the upstream swirl blades and the downstream swirl blades are all provided with an included angle with the axial direction.

Preferably: the gas air premixing chamber is a cylinder with openings at both ends. The gas air premixing chamber is provided with a premixing chamber fan flange on the end face of one end, and a flange is provided on the end face of the other end. The end face of the flange is open. There are bolt holes.

Preferably: the Venturi annular gas chamber includes a first reducing tube, a second reducing tube, an outer Venturi tube and an inner Venturi tube;

The inner venturi tube is located in the outer venturi tube. The left and right ends of the inner venturi tube are connected to the left and right ends of the outer venturi tube through the first reducing tube and the second reducing tube respectively. The outer venturi tube and the inner venturi tube The outer venturi annular cavity gas injection holes and the inner venturi annular cavity gas injection holes are respectively opened on the wall of the inner pipe. The outer venturi annular cavity gas injection holes and the inner venturi annular cavity gas injection holes are equally spaced or misaligned. Distribution or dense distribution or different hole diameter distribution on the inner and outer tubes, and the opening direction is perpendicular to the central axis of the gas-air premixing chamber. There are connections on the end faces of the small diameter ends of the first reducer tube and the second reducer tube. Flange, the two connecting flanges are respectively connected to the upstream swirl blade and the downstream swirl blade through the upstream swirl blade fixed flange and the downstream swirl blade fixed flange. The bottom end of the outer venturi tube is provided with an internally threaded pipe joint. One end of the internally threaded pipe joint is connected to the inside of the venturi annular gas chamber, and the other end is threadedly connected to the main gas pipe.

Preferably: the bottom end of the cylinder is provided with an opening, the main gas pipe is located in the opening, the opening end is provided with a main gas pipe fixed joint, the main gas pipe fixed joint and the fixed flange are connected through a first bolt, and the main gas pipe is A limiting boss is provided at a position opposite to the fixed joint of the main gas pipe, and a sealing ring is installed on the lower end of the limiting boss.

Preferably: the upstream swirl blade fixed flange and the downstream swirl blade fixed flange are respectively provided with a plurality of upstream swirl blade mounting holes and a plurality of downstream swirl blade holes, and the upstream swirl blades and downstream swirl blades are respectively tightened. Install the fastening bolts on the flow blade mounting holes and the downstream swirl blade holes.

Compared with existing products, the present invention has the following effects: due to the special annular gas chamber structure, the air is sucked in by the fan and then turbulent by the upstream swirl blades before entering the inner air duct and the outer air duct, and the gas passes through the Venturi annular gas chamber. The gas jet air enters the inner air duct and the outer air duct, and mixes with the air. Finally, it is fully mixed again through the downstream swirl blades, so the air and gas can be fully mixed, and the air and gas are mixed within a limited premixing distance. Full mixing can be achieved within the system, thereby achieving uniform mixing of gas and air, thereby improving combustion.

Description of the drawings

Figure 1 is a schematic structural diagram of a fully premixed surface burner gas-air blender according to the present invention;

Figure 2 is a schematic structural diagram of the installation position of the swirl blade;

Figure 3 is a schematic structural diagram of the Venturi annular gas chamber:

Figure 4 is a schematic diagram of the connection structure between the main gas pipe and the gas air premixing chamber.

In the picture: 1-gas air premixing chamber; 2-upstream swirl blades; 3-downstream swirl blades; 4-Venturi annular gas chamber; 5-main gas pipe; 51-inner horizontal pipe; 52-outer layer Horizontal pipe; 53-first reducing pipe; 54-second reducing pipe; 6-inner air duct, 7-outer air duct; 8-fan; 9-fixed flange; 11-premix chamber fan flange; 12-flange, 13-main gas pipe fixed joint, 21-upstream swirl blade fixed flange, 31-downstream swirl blade fixed flange, 41-first reducing pipe, 42-second reducing pipe, 43 -Outer Venturi tube, 44-inner Venturi tube, 45-outer Venturi annular cavity gas injection hole, 46-inner Venturi annular cavity gas injection hole, 47-internal threaded pipe joint, 410-connecting flange, 51- Limiting boss, C1-sealing ring.

Detailed ways

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in Figures 1 to 4, a fully premixed surface burner gas air mixer according to the present invention includes a gas air premixing chamber 1, an upstream swirl blade 2, a downstream swirl blade 3, a venturi Annular gas chamber 4, main gas pipe 5, inner air duct 6, outer air duct 7 and fixed flange 9;

The Venturi annular gas chamber 4 is located in the gas and air premixing chamber 1 and is coaxially arranged. One end of the main gas pipe 5 is fixed on the gas and air premixing chamber 1 through a fixed flange 9, and the other end passes through the gas and air premixing chamber 1. It is connected with the Venturi annular gas chamber 4. The Venturi annular gas chamber 4 is provided with an inner air duct 6. There is an outer air duct 7 between the Venturi annular gas chamber 4 and the gas air premixing chamber 1. The Venturi annular gas chamber 4 is connected with the Venturi annular gas chamber 4. The two ends of the cavity 4 are respectively provided with upstream swirl blades 2 and downstream swirl blades 3, and the upstream swirl blades 2 and the downstream swirl blades 3 have an included angle with the axial direction.

Further: the gas air premixing chamber 1 is a cylinder with openings at both ends. The gas air premixing chamber 1 is provided with a premixing chamber fan flange 11 on the end face of one end, and a flange 12 is provided on the end face of the other end. The flange 12 There are bolt holes 121 on the end face.

Further: the Venturi annular gas chamber 4 includes a first reducing tube 41, a second reducing tube 42, an outer Venturi tube 43 and an inner Venturi tube 44;

The inner venturi tube 44 is located in the outer venturi tube 43. The left and right ends of the inner venturi tube 44 are connected to the left and right ends of the outer venturi tube 43 through the first reducing tube 41 and the second reducing tube 42 respectively. The outer venturi annular cavity gas injection hole 45 and the inner venturi annular cavity gas injection hole 46 are respectively opened on the tube walls of the outer venturi tube 43 and the inner venturi tube 44. The outer venturi annular cavity gas injection hole 45 and the inner venturi annular cavity gas injection hole 45 The gas injection holes 46 in the inner annular cavity are equally spaced or staggered, or are densely distributed or have different hole diameters on the inner and outer tubes, and the opening direction is perpendicular to the central axis of the gas-air premixing chamber 1. The first reducing tube 41 and the small-diameter end of the second reducer 42 are provided with connecting flanges 410. The two connecting flanges 410 are respectively connected to the upstream swirl blades through the upstream swirl blade fixed flange 21 and the downstream swirl blade fixed flange 31. 2 is connected to the downstream swirl blade 3. The bottom end of the outer venturi pipe 43 is provided with an internally threaded pipe joint 47. One end of the internally threaded pipe joint 47 is internally connected with the venturi annular gas chamber 4, and the other end is threaded with the main gas pipe 5 connect.

Further: the bottom end of the cylinder is provided with an opening, the main gas pipe 5 is located in the opening, and the main gas pipe fixed joint 13 is provided at the end of the opening. The main gas pipe fixed joint 13 and the fixed flange 9 are connected through the first bolt 9131. The main gas pipe 5 is provided with a limiting boss 51 at a position opposite to the main gas pipe fixed joint 13, and a sealing ring C1 is installed on the lower end of the limiting boss 51.

Further: the upstream swirl blade fixed flange 21 and the downstream swirl blade fixed flange 31 are respectively provided with a plurality of upstream swirl blade mounting holes 211 and a plurality of downstream swirl blade holes 311. The upstream swirl blade 2 and the downstream swirl blade The blades 3 are respectively installed on the flow blade mounting holes 211 and the downstream swirl blade holes 311 through fastening bolts.

working principle:

The fully premixed surface burner mixer uses double swirl blades and an inner and outer venturi channel structure. The fan 8 draws air 1F upstream of the new gas-air mixing structure, forming an outer passage 2F and an inner passage 3F at the upstream swirl blades. The air in the 2F passage enters the Venturi annular cavity 4, and the air in the 3F passage passes through the upstream swirl blade. After being disturbed by the flow blades, it enters the outer air duct to form swirling air 4F; the gas is supplied from the external gas pipe along the passage 5F, forming a circulation passage 6F in the venturi annular gas chamber 4, part of which is formed by the gas injection hole 45 of the outer venturi annular cavity The gas 8F flows out to the outer air duct 7; the other part flows out from the inner venturi annular cavity gas injection hole 46 to form the gas 7F to the inner air duct 6. The gas 8F passing through the outer air duct 4 is mixed with the swirling air 4F, and the mixing is enhanced by the downstream swirling blades 3 to form a uniform gas-air mixture 10F; the gas 7F passing through the inner air duct 6 is mixed with the air in the 3F passage Finally, the mixed gas 9F is formed, and finally the mixed gas in the inner and outer air ducts merges downstream of the high-efficiency gas air mixing structure to form a uniform mixed gas 11F.

This embodiment is only an illustrative description of this patent and does not limit its protection scope. Those skilled in the art can also make partial changes to it. As long as the spirit and essence of this patent are not exceeded, they are all within the protection scope of this patent.

Claims (4)

1. A fully premixed surface burner gas-air blender, characterized by: including a gas-air premixing chamber (1), an upstream swirl blade (2), a downstream swirl blade (3), and a Venturi annular Gas chamber (4), main gas pipe (5), internal air duct (6), external air duct (7) and fixed flange (9); The Venturi annular gas chamber (4) is located in the gas-air premixing chamber (1) and is coaxially arranged. One end of the main gas pipe (5) is fixed to the gas-air premixing chamber (1) through a fixed flange (9) on the top, the other end passes through the gas-air premixing chamber (1) and is connected to the Venturi annular gas chamber (4). The Venturi annular gas chamber (4) is equipped with an internal air duct (6), and the Venturi annular gas chamber (4) 4) There is an external air duct (7) between the gas air premixing chamber (1), and the two ends of the Venturi annular gas chamber (4) are respectively equipped with upstream swirl blades (2) and downstream swirl blades (3). ), the upstream swirl blade (2) and the downstream swirl blade (3) are provided with an included angle with the axial direction; The Venturi annular gas chamber (4) includes a first reducing tube (41), a second reducing tube (42), an outer Venturi tube (43) and an inner Venturi tube (44); The inner venturi tube (44) is located in the outer venturi tube (43), and the left and right ends of the inner venturi tube (44) are connected to each other through the first reducing tube (41) and the second reducing tube (42) respectively. The left and right ends of the outer venturi tube (43) are connected. The outer venturi annular cavity gas injection hole (45) and the inner venturi are respectively opened on the walls of the outer venturi tube (43) and the inner venturi tube (44). The gas injection holes (46) in the inner annular cavity, the gas injection holes (45) in the outer venturi annular cavity and the gas injection holes (46) in the inner venturi annular cavity are equally spaced or staggered, or the density of the inner and outer tubes is different or different. The hole diameter is distributed, and the opening direction is perpendicular to the central axis of the gas-air premixing chamber (1). The first reducing pipe (41) and the second reducing pipe (42) are provided with connecting flanges on the end faces of the small diameter ends. (410), the two connecting flanges (410) are connected to the upstream swirl blade (2) and the downstream swirl blade (3) respectively through the upstream swirl blade fixed flange (21) and the downstream swirl blade fixed flange (31). ) are connected to each other, and the bottom end of the outer venturi pipe (43) is provided with an internally threaded pipe joint (47). One end of the internally threaded pipe joint (47) is internally connected to the venturi annular gas chamber (4), and the other end is connected to the main gas pipe. (5)Threaded connection. 2. A fully premixed surface burner gas-air blender according to claim 1, characterized in that: the gas-air premixing chamber (1) is a cylinder with both ends open, and the gas-air premixing chamber (1) is a cylinder with both ends open. A premixing chamber fan flange (11) is provided on the end face of one end of the chamber (1), a flange (12) is provided on the end face of the other end, and a bolt hole (121) is provided on the end face of the flange (12). 3. A fully premixed surface burner gas-air blender according to claim 2, characterized in that: the bottom end of the cylinder is provided with an opening, and the main gas pipe (5) is located in the opening, and the opening There is a main gas pipe fixed joint (13) at the end. The main gas pipe fixed joint (13) is connected to the fixed flange (9) through the first bolt (9131). The main gas pipe (5) is fixed to the main gas pipe. A limiting boss (51) is provided at the relative position of the joint (13), and a sealing ring (C1) is installed on the lower end of the limiting boss (51). 4. A fully premixed surface burner gas-air blender according to claim 1, characterized in that: the upstream swirl blade fixed flange (21) and the downstream swirl blade fixed flange (31 ) are respectively provided with a plurality of upstream swirl blade mounting holes (211) and a plurality of downstream swirl blade holes (311). The upstream swirl blades (2) and downstream swirl blades (3) are respectively installed on the flow through fastening bolts. On the blade mounting hole (211) and the downstream swirl blade hole (311).