Premixer of combustor

Abstract

The utility model discloses a premixer of a combustor, which comprises a cylinder body with a mixing cavity inside, and an air inlet and a mixed gas outlet which are communicated with the mixing cavity are respectively arranged at two ends of the cylinder body, and is characterized in that a turbulent flow impeller is arranged at the mixed gas outlet, a gas outlet pipe is further arranged in the mixing cavity, and a gas outlet pipe is arranged in the mixing cavity. The gas outlet pipe and the mixing cavity are coaxially arranged, a gas cavity is formed in the gas outlet pipe, the front end of the gas outlet pipe is arranged close to the turbulent flow impeller, and the rear end of the gas outlet pipe is communicated with a gas supply pipe; the outer diameter of the middle of the gas outlet pipe is larger than the outer diameters of the two ends of the gas outlet pipe, the outer edge of the middle of the gas outlet pipe is arranged close to the inner wall of the mixing cavity, a plurality of gas outlet holes are annularly and evenly distributed in the outer edge face of the middle of the gas outlet pipe, and the gas cavity is communicated with the mixing cavity through the gas outlet holes. The gas mixing uniformity is improved, the size is reduced, and the combustion efficiency is improved.

Description

Technical Field

[0001] The utility model relates to a combustion system, in particular to a premixer of a burner. Background Art

[0002] In a fully premixed combustion system, such as a boiler, a premixer is installed before the burner to mix the gas and air to improve combustion efficiency and reduce gas usage.

[0003] In the prior art, common premixers basically adopt a Venturi-type arrangement structure, where a ring-shaped gas chamber 103 structure with an annular cavity is formed by two components, a convergent pipe 101 and a divergent pipe 102. Air passes through the inside of the annular gas chamber, and the gas is sent out from the annular gas chamber to mix with the air. The gas enters the air from the outer ring of the air flowing through the annular gas chamber to mix, and the gas inlet 104 can only be set at one side of the mixing pipe. Figure 1 As shown. Since the gas inlet can only be set on one side of the mixing tube, when this type of mixing tube is arranged, in order to ensure uniform gas pressure and flow rate in the annular gas chamber and uniform mixing of air and gas in the mixing tube, the gas chamber in the mixing tube needs to be set large enough. In this way, the space occupied is large and the cost is higher. At the same time, if the mixing tube is working normally (when the air is flowing normally), the gas valve will be opened for a period of time, and the pressure in the annular gas chamber will be inconsistent and the airflow distribution will be uneven, resulting in uneven mixing of gas and air.

[0004] At the same time, when the applied power and size of the mixing tube of this structure increase, the gas enters from the outer ring of the air, and the air flow rate is faster at this time. The mixing of gas and air occurs in the outer area of ​​the air, and the mixing effect is poor. Therefore, how to solve the above technical problems is the direction that technicians in this field need to work hard on. Summary of the invention

[0005] The utility model aims to provide a premixer for a burner. By using the structure, the mixing effect is improved and the subsequent combustion efficiency is improved.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a premixer of a burner, comprising a cylinder with a mixing chamber inside, an air inlet and a mixed gas outlet connected to the mixing chamber are respectively arranged at two ends of the cylinder, a turbulent impeller is installed at the mixed gas outlet, an air outlet pipe is also arranged in the mixing chamber, the air outlet pipe is coaxially arranged with the mixing chamber, a fuel gas chamber is arranged inside the air outlet pipe, the front end of the air outlet pipe is arranged close to the turbulent impeller, and the rear end of the air outlet pipe is connected to a fuel gas supply pipe;

[0007] The outer diameter of the middle part of the gas outlet pipe is larger than the outer diameters of the two ends of the gas outlet pipe. The outer edge of the middle part of the gas outlet pipe is arranged close to the inner wall of the mixing chamber. A plurality of gas outlet holes are evenly distributed in an annular pattern on the outer edge surface of the middle part of the gas outlet pipe. The gas outlet holes connect the gas chamber with the mixing chamber.

[0008] In the above technical solution, the air outlet pipe is a spindle structure that is large in the middle and small at both ends.

[0009] In the above technical solution, the middle outer surface of the outlet pipe has a straight section, the straight section is arranged parallel to the inner wall of the mixing chamber, and the outer diameter of the straight section is arranged at the maximum outer diameter of the outlet pipe;

[0010] The gas outlet is arranged on the straight section.

[0011] In the above technical solution, the outer diameter of the air outlet pipe gradually decreases from the straight section toward both ends, and the front end of the air outlet pipe is a closed pointed structure.

[0012] In the above technical solution, the front end of the gas supply pipe is connected to the rear end of the gas outlet pipe, and the rear end of the gas supply pipe passes through the cylinder and is arranged outside the cylinder.

[0013] In the above technical solution, a sleeve is also sleeved on the outside of the connection between the rear end of the gas outlet pipe and the gas supply pipe, and the outer surface of the sleeve is connected to the inner wall of the mixing chamber via a connecting frame.

[0014] In the above technical solution, the connecting frame includes multiple connecting rods, which are evenly distributed in an annular shape on the outer surface of the sleeve, the inner ends of the connecting rods are connected to the outer surface of the sleeve, and the outer ends of the connecting rods are connected to the inner wall of the mixing chamber.

[0015] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art:

[0016] 1. In the utility model, the gas outlet pipe is coaxially arranged inside the mixing chamber, and the gas is sent from the gas outlet hole of the gas outlet pipe to the mixing chamber to mix with the air. Compared with the gas chamber of the previous annular cavity, the pressure of the gas at various places inside the gas outlet pipe can be basically kept consistent, and the size can be more miniaturized, which reduces the cost and space occupation;

[0017] 2. In the utility model, when the gas is turned on, the annular airflow distribution of each gas outlet can be ensured to be uniform, and the airflow distribution can be ensured to be uniform, and the mixing uniformity with the air can be ensured;

[0018] 3. The gas distribution in the utility model adopts a ring structure composed of multiple gas outlet holes. Compared with the previous Venturi structure, it can better control the processing accuracy and dimensional error, and better control the ratio of gas to air, so as to ensure the subsequent combustion efficiency and save energy consumption;

[0019] 4. In the utility model, the gas flow space from the air inlet to the maximum outer diameter of the gas outlet pipe and then to the mixer outlet is also a Venturi structure. The gas flow rate reaches the maximum at the maximum outer diameter of the gas outlet pipe. At this time, the gas flow rate is the maximum and the pressure is the minimum. The gas outlet pressure requirement of the circular hole of the gas outlet pipe is reduced, which can reduce the gas demand pressure, so that the gas demand pressure of the burner using the premixer is reduced;

[0020] 5. The outlet pipe in the utility model is a structure with a large middle and small ends. The fuel gas is mixed with the air from the inner ring of the air, and the mixed gas flows to the entire mixing chamber through the contour part of the outlet pipe, which can achieve a good mixing effect of air and fuel gas, reduce the excess air coefficient as much as possible, reduce the carbon monoxide generation rate, and improve the combustion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the background technology;

[0022] Figure 2 It is a schematic diagram of the structure of the first embodiment of the present utility model;

[0023] Figure 3 This is a schematic diagram of a half-section structure in Embodiment 1 of the present utility model;

[0024] Figure 4 yes Figure 3 A partial enlarged view of the middle straight section.

[0025] Among them: 1. mixing chamber; 2. cylinder; 3. air inlet; 4. mixed gas outlet; 5. turbulent impeller; 6. outlet pipe; 7. fuel gas chamber; 8. fuel gas supply pipe; 9. fuel gas outlet hole; 10. gradually contracting space; 11. gradually expanding space; 12. straight section; 13. sleeve; 14. connecting frame; 15. flange; 16. connecting flange; 101. gradually contracting pipe; 102. gradually expanding pipe; 103. annular fuel gas chamber; 104. fuel gas inlet. DETAILED DESCRIPTION

[0026] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0027] Example 1: See Figures 2 to 4As shown, a premixer of a burner comprises a cylinder 2 with a mixing chamber 1 inside, an air inlet 3 and a mixed gas outlet 4 connected to the mixing chamber 1 are respectively arranged at two ends of the cylinder 2, a turbulent impeller 5 is installed at the mixed gas outlet 4, an outlet pipe 6 is also arranged in the mixing chamber 1, the outlet pipe 6 is coaxially arranged with the mixing chamber 1, a fuel gas chamber 7 is arranged inside the outlet pipe 6, the front end of the outlet pipe 6 is arranged close to the turbulent impeller 5, and the rear end of the outlet pipe 6 is connected to a fuel gas supply pipe 8;

[0028] The outer diameter of the middle part of the gas outlet pipe 6 is larger than the outer diameters of the two ends of the gas outlet pipe 6. The outer edge of the middle part of the gas outlet pipe 6 is arranged close to the inner wall of the mixing chamber 1. A plurality of gas outlet holes 9 are evenly distributed in a ring on the outer edge surface of the middle part of the gas outlet pipe 6. The gas outlet holes 9 connect the gas chamber 7 with the mixing chamber 1.

[0029] In the present embodiment, in actual use, since the air outlet pipe is coaxially arranged in the mixing chamber, the outer diameter of the middle part of the air outlet pipe is larger than the outer diameters of the two ends of the air outlet pipe, so that the air enters the mixing chamber from the air inlet, flows through the outer surface of the air outlet pipe, and then flows out from the mixed gas outlet, that is, the mixing chamber from the air inlet to the maximum outer diameter of the air outlet pipe is a gradually contracting space 10 (the volume changes from large to small), and the mixing chamber from the maximum outer diameter of the air outlet pipe to the mixed gas outlet is a gradually expanding space 11 (the volume changes from small to large), and the air flow space is also a Venturi structure, and the middle outer diameter of the air outlet pipe is the throat of the air flow channel (the air flow area and volume are the smallest), and the gas is supplied through the gas supply pipe and sent into the air outlet pipe, and then it will be sent from multiple gas outlets to the throat of the mixing chamber and mixed with the air flowing through the throat. The air flowing through the throat is annular, and a plurality of gas outlet holes are evenly distributed in annular shapes on the outer surface of the middle of the gas outlet pipe, that is, forming an annular gas channel, so that the gas is sent out from the gas outlet hole and will contact the inside of the annular cavity flowing through the throat, so that the gas is mixed from the inside of the air to the outside, and then the mixed gas of air and gas is expanded through the gradually expanding space at the rear end to mix in the entire gradually expanding space. Compared with the previous method of mixing with air from the outside to the inside, the mixing is more uniform and the mixing effect is better. Among them, the mixed gas will flow out from the mixed gas outlet and pass through the turbulent impeller, and the turbulent impeller will further enhance the mixing effect of the gas and air. Among them, in this embodiment, the gas outlet hole adopts a circular structure.

[0030] At the same time, in this embodiment, the gas cavity is inside the gas outlet pipe, not the conventional annular cavity structure, so that during normal mixing, the gas pressure at various locations inside the gas cavity is basically consistent. At the same time, after the gas valve is opened, the gas supply pipe supplies gas to the gas cavity, which can ensure that the gas flow distribution of the annular gas distribution ring composed of multiple gas outlets is uniform, and can avoid the situation that the annular distribution ring may have uneven pressure in the annular cavity in the conventional structure, resulting in uneven gas flow distribution, so as to ensure the uniformity of gas and air mixing. At the same time, the use of multiple gas outlets to form an annular structure can better control the processing accuracy and dimensional error, and better control the ratio of gas to air, thereby ensuring the subsequent combustion efficiency and saving energy consumption;

[0031] The outlet pipe is a spindle structure with a large center and small ends. The outer diameter of the outlet pipe gradually increases from the back to the center, and the outer diameter of the outlet pipe gradually decreases from the center to the front, thereby realizing the gradual contraction and expansion of air flow.

[0032] See also Figures 2 to 4 As shown, the middle outer surface of the outlet pipe 6 has a straight section 12, and the straight section 12 is arranged parallel to the inner wall of the mixing chamber 1, and the outer diameter of the straight section 12 is arranged at the maximum outer diameter of the outlet pipe 6;

[0033] The gas outlet hole 9 is arranged on the straight section 12 .

[0034] The outer diameter of the outlet pipe gradually decreases from the straight section toward the two ends, and the front end of the outlet pipe is a closed pointed structure. The pointed structure makes the gradually expanding space at the front end larger, and increases the mixing space of gas and air as much as possible. At the same time, the setting of the straight section makes the outer wall of the outlet pipe at this place an annular structure, and the gas outlet hole is set on the straight section, so as to form a gas distribution ring, which contacts with the air from the inside to the outside, thereby ensuring the uniformity of mixing with the air.

[0035] See also Figure 2 , 3 As shown, the front end of the gas supply pipe is connected to the rear end of the gas outlet pipe, and the rear end of the gas supply pipe passes through the cylinder and is arranged outside the cylinder. In this embodiment, the rear ends of the gas supply pipe and the gas outlet pipe are screwed, which is convenient for installation and disassembly. The connection between the gas supply pipe and the cylinder can be connected and fixed by welding.

[0036] See also Figure 2 , 3 As shown, a sleeve 13 is sleeved outside the connection between the rear end of the gas outlet pipe 6 and the gas supply pipe 8 , and the outer surface of the sleeve 13 is connected to the inner wall of the mixing chamber via a connecting frame 14 .

[0037] The connecting frame includes a plurality of connecting rods, which are evenly distributed in an annular shape on the outer surface of the sleeve, the inner ends of the connecting rods are connected to the outer surface of the sleeve, and the outer ends of the connecting rods are connected to the inner wall of the mixing chamber.

[0038] In this embodiment, the sleeve is used to support and position the connection between the gas outlet pipe and the gas supply pipe, and the sleeve is connected to the inner wall of the cylinder by a connecting rod, so as to prevent the gas outlet pipe from shaking during the gas flow, ensure the stability of the mixing, reduce the maintenance rate, and extend the service life. In addition, the sleeve is positioned by a connecting rod, which does not affect the normal flow of air.

[0039] Among them, one end of the gas supply pipe is connected to the rear end of the outlet pipe, and the other end is outside the cylinder. It has a flange 15 for connecting to an external gas source providing mechanism. A connecting flange 16 is provided on the outer surface of the rear end of the cylinder for connecting to other components. In this structure, the length of the cylinder and the outlet pipe can be shorter, the size and space occupied are smaller, and the cost is lower.

[0040] In the description of the present invention, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0041] In the present utility model, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, or a detachable connection, or an integral one; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, for example, the two can form a mechanical abutment or abutment connection through abutment, contact, etc., the two can also be directly hung or hung through an intermediate medium, etc., or it can be the internal connection of the two elements or the interaction relationship between the two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A premixer for a burner, comprising a cylinder having a mixing chamber therein, wherein two ends of the cylinder are respectively provided with an air inlet and a mixed gas outlet communicating with the mixing chamber, wherein: A turbulent impeller is installed at the outlet of the mixed gas, and an outlet pipe is also arranged in the mixing chamber. The outlet pipe is coaxially arranged with the mixing chamber, and a fuel gas chamber is arranged inside the outlet pipe. The front end of the outlet pipe is arranged close to the turbulent impeller, and the rear end of the outlet pipe is connected to a fuel gas supply pipe; The outer diameter of the middle part of the gas outlet pipe is larger than the outer diameters of the two ends of the gas outlet pipe. The outer edge of the middle part of the gas outlet pipe is arranged close to the inner wall of the mixing chamber. A plurality of gas outlet holes are evenly distributed in an annular pattern on the outer edge surface of the middle part of the gas outlet pipe. The gas outlet holes connect the gas chamber with the mixing chamber.

2. The premixer of the burner according to claim 1, characterized in that: The air outlet pipe is a spindle structure that is large in the middle and small at both ends.

3. The premixer of the burner according to claim 1, characterized in that: The middle outer surface of the outlet pipe has a straight section, the straight section is arranged parallel to the inner wall of the mixing chamber, and the outer diameter of the straight section is arranged at the maximum outer diameter of the outlet pipe; The gas outlet is arranged on the straight section.

4. The premixer of the burner according to claim 3, characterized in that: The outer diameter of the air outlet pipe gradually decreases from the straight section toward two ends, and the front end of the air outlet pipe is a closed pointed structure.

5. The premixer of the burner according to claim 1, characterized in that: The front end of the gas supply pipe is connected to the rear end of the gas outlet pipe, and the rear end of the gas supply pipe passes through the cylinder and is arranged outside the cylinder.

6. The premixer of the burner according to claim 1, characterized in that: A sleeve is also sleeved on the outside of the connection between the rear end of the gas outlet pipe and the gas supply pipe, and the outer surface of the sleeve is connected to the inner wall of the mixing chamber via a connecting frame.

7. The premixer of the burner according to claim 6, characterized in that: The connecting frame includes a plurality of connecting rods, which are evenly distributed in an annular shape on the outer surface of the sleeve, the inner ends of the connecting rods are connected to the outer surface of the sleeve, and the outer ends of the connecting rods are connected to the inner wall of the mixing chamber.

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