Mixers and gas combustion systems

Abstract

The present application provides a mixer and a gas combustion system. The mixer comprises: a venturi (32) having an air inlet (321), a gas inlet (322) and a mixed gas outlet (323), the gas inlet (322) being arranged at a throat (325) of the venturi; an adjusting component (34) arranged in the venturi (32) and downstream of the throat, the adjusting component (34) being capable of being driven to move towards or away from the throat (325) so as to change the flow area of the gas in the venturi (32).

Description

TECHNICAL FIELD

[0001] The present application relates to the field of gas combustion, and in particular to a mixer for premixing air and gas in a gas combustion system and a gas combustion system having the same. BACKGROUND

[0002] Gas combustion can be classified into diffusion combustion, partial premixed combustion (atmospheric combustion) and full premixed combustion. Full premixed combustion refers to a process in which air and gas are premixed in a certain ratio to form a premixed gas, and the premixed gas is ignited and combusted in a burner. Premixed combustion generally occurs in a relatively closed system. Compared with diffusion combustion, premixed combustion has faster flame propagation speed, higher combustion temperature and better spreadability, and is widely used in industrial boilers.

[0003] A typical premixed combustion system generally uses a Venturi mixer to ensure that air and gas are fully mixed in a certain ratio, and a fan is used to send the premixed gas into the burner. The mixing of gas and air can be arranged at the inlet of the fan, which is called "front premixing". The mixing of gas and air can also be arranged at the outlet of the fan, which is called "rear premixing".

[0004] The front premixing system is more commonly used in the market. Since the front premixing combustion system mixes gas and air at the inlet of the fan, a special EC (Electrical Commutation) fan, i.e. a fan with a direct-current brushless variable-frequency motor, is required, which is expensive and the specification requires that the power of the EC fan can only be up to 2.8 MW.

[0005] The rear premixing combustion system has very high requirements for the mixer due to the short mixing distance. The static rear premixing mixer is commonly seen in the market, and the structure of the Venturi tube is static. This static rear premixing mixer is difficult to achieve high regulation ratio at low load, because at low load the flow rate is low and the mixing effect of air and gas is poor, which leads to deterioration of combustion conditions, greatly limiting the promotion and application of the rear premixing system in the market. In order to improve the mixing effect, some rear premixing mixers of the prior art increase the number of swirl vanes or increase the resistance of the flow channel, but the internal mechanical structure of the mixer is still static, and it cannot adapt to the condition of low load. Therefore, it is necessary to develop a mixer suitable for a high-power rear premixing system to broaden the application range of full premixed combustion. SUMMARY

[0006] In view of this, one object of the present invention is to provide a mixer for a post-premixed combustion system, which can effectively improve the mixing effect under low load conditions, that is, under low flow rates. Another object of the present invention is to provide a mixer for a post-premixed combustion system and a combustion system thereof, which can achieve a higher regulation ratio under low fire flow rates. Another object of the present invention is to provide a mixer for a post-premixed combustion system and a combustion system thereof, which can have lower requirements for gas pressure. Yet another object of the present invention is to provide a mixer for a post-premixed combustion system and a combustion system thereof, which can not only realize gas flow regulation, but also enable the flow regulation device to be integrated into the mixer, so that the combustion system structure is simple.

[0007] In one embodiment of the present invention, a mixer is provided in a gas combustion system to mix air and gas to form a combustible mixed gas. The mixer is characterized in that it includes: a venturi tube having an air inlet, a gas inlet, and a mixed gas outlet, the venturi tube having a central axis and a throat located between the air inlet and the mixed gas outlet along the central axis, the gas inlet being located at the throat; an adjustment component disposed in the venturi tube and downstream of the throat, the adjustment component being capable of being driven to move toward or away from the throat along the central axis, thereby changing the flow area of ​​the gas in the venturi tube. Preferably, the adjustment component is a conical valve plug, the conical outer surface of which, on the side facing the throat, cooperates with the inner surface of the throat of the venturi tube.

[0008] Preferably, the mixer further comprises a driving mechanism for driving the adjusting component, the driving mechanism comprising: a central shaft, which is placed in the venturi tube in a manner capable of reciprocating along the central axis direction, the adjusting component being sleeved and fixed on the central shaft; a transmission assembly, one end of which is connected to the central shaft and the other end is connected to an actuator, the transmission assembly causing the central shaft to move under the drive of the actuator.

[0009] More preferably, the transmission assembly includes: a transmission shaft, which extends in a direction perpendicular to the direction of the central axis and rotates under the drive of the actuator; a shaft shifter, one end of which is fixedly connected to the transmission shaft and the other end is connected to the central shaft, wherein the transmission shaft rotates to drive the shaft shifter, and then the shaft shifter pushes the central shaft to move linearly along the central axis.

[0010] Particularly preferably, the shifter is fixedly sleeved on the transmission shaft, and the shifter extends two lever parts in a direction perpendicular to the transmission shaft, the two lever parts are spaced apart and arranged in parallel with each other so that the central axis is suitable for being placed therebetween, and each lever part has a long hole along its length direction; a connecting rod is suitable for passing through the long holes of the two lever parts and the through hole on the central axis placed between the two lever parts, and the connecting rod is parallel to the transmission shaft.

[0011] Another embodiment of the present invention provides a gas combustion system, characterized in that it includes: an air channel in which a fan is provided for blowing air; a gas channel for providing gas; a mixer as described above, wherein the air inlet is connected to the air channel, the gas inlet is connected to the gas channel, and the mixed gas outlet is connected to a combustion furnace; an actuator, which is connected to the mixer and is used to drive the regulating component in the mixer; a combustion controller, which is connected to the actuator and drives the regulating component by controlling the actuator to adjust the gas flow.

[0012] Preferably, the gas combustion system further comprises a first sensor for sensing the temperature and / or pressure in the combustion furnace, the combustion controller is connected to the first sensor, and controls the actuator in response to the sensing data of the first sensor. Preferably, the gas combustion system further comprises a proportional control valve, which uses a diaphragm mechanical structure to make the differential pressure of the air channel and the differential pressure of the gas channel constant in proportion. More preferably, the gas combustion system further comprises a second sensor, which is arranged at the fan and is used to sense the air velocity; the combustion controller is connected to the second sensor, and suspends ignition and restarts the fan in response to the second sensor. Particularly preferably, the gas combustion system further comprises a human-machine interaction panel, which is connected to the combustion controller.

[0013] An adjustment component is used within the mixer to adjust the flow rate based on the load. When the load decreases, the adjustment component moves in the direction of the airflow (toward the throat), reducing the flow area within the Venturi tube and increasing the flow rate. This maintains a higher flow rate and flow resistance even at low flows / light loads. This increases the Reynolds number and turbulence, ensuring better mixing even at low burns in the furnace. Furthermore, the aforementioned mixer with dynamic adjustment capabilities can simultaneously achieve mixing and flow regulation, thereby reducing the number of mixer components and achieving certain cost savings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 1 is a schematic structural diagram of a post-premixed gas combustion system according to an embodiment of the present invention;

[0015] Figure 2 is a perspective view of a mixer according to one embodiment of the present invention;

[0016] Figure 3 is a cross-sectional view of a mixer according to one embodiment of the present invention;

[0017] Figure 4 FIG. 1 is a schematic diagram of adjusting the position of components in a mixer under heavy load according to one embodiment of the present invention.

[0018] List of reference numerals:

[0019] 100: Combustion system

[0020] 10: Air channel 12: Air filter 14: Fan,

[0021] 20: Gas channel 22: Proportional control valve 24: Gas single valve

[0022] 30: Mixer

[0023] 32: Venturi tube 321: Air inlet 322: Gas inlet 323: Mixed gas outlet

[0024] 325: throat 34: adjustment part

[0025] 36: driving mechanism 361: central shaft 363: transmission assembly 363-1: transmission shaft

[0026] 363-2: Shifter T: Shifter L: Long hole R: Connecting rod

[0027] 40: Combustion furnace 50: Combustion controller 60: Actuator

[0028] 72: First sensor 74: Ion needle 76: Air pressure sensor DETAILED DESCRIPTION

[0029] Figure 1 A post-premixed combustion system 100 is shown as an example. Figure 1 As shown, the combustion system 100 includes an air passage 10 , a gas passage 20 , a mixer 30 connected to the air passage and the gas passage, a combustion furnace 40 connected to an outlet of the mixer 30 , and a combustion controller 50 .

[0030] An air filter 12 is provided at the entrance of the air passage 10 for filtering foreign matter (such as dust, waste residue, etc.) contained in the air. A fan 14 is also provided in the air passage 10, which is capable of blowing air into a mixer 30 and then into a combustion furnace 40. The mixer 30 is placed downstream of the fan 14. One inlet of the mixer 30 is connected to the air passage 10, and its outlet is connected to the combustion furnace 40. The other inlet of the mixer 30 is connected to the gas passage 20. The mixer 30 is capable of premixing air and gas downstream of the fan 12 and delivering the premixed gas into the combustion chamber 40. An igniter is provided in the combustion chamber 40, which can ignite under the control of a combustion controller 50 to ensure that the premixed combustible gas is fully burned.

[0031] like Figure 1 The post-premix combustion system shown in the figure has lower requirements for the fan because the premixing of gas and air occurs downstream of the fan, so a more cost-effective ordinary fan can be used. The post-premix combustion system also has the characteristics of short mixing distance and high efficiency. This also puts very high demands on the mixer, which needs to be able to adapt to the requirements for air-fuel mixing effects under different loads. Taking this into consideration, the inventors of the present invention have proposed a mixer with adjustable flow rate, an exemplary structure of which is shown in FIG. Figures 2-4 The mixer can automatically adjust the amount of air and gas according to the load of the burner.

[0032] Figures 2-4 Schematically showing a perspective view and a cross-sectional view of a mixer 30 according to an embodiment of the present invention. Figures 2-4 As shown, the mixer 30 is a Venturi mixer, which is basically composed of a Venturi tube 32. Unlike traditional Venturi mixers, the mixer 30 according to an embodiment of the present invention further has an adjustment component 34, which is placed in the Venturi tube 32 and can be driven to change the gas flow area in the Venturi tube, thereby adjusting the amount of air and gas.

[0033] Specifically, as shown in the figure, the Venturi tube 32 is generally tubular and extends along its central axis direction A. The inlet of the Venturi tube is the air inlet 321, which is connected to the air passage 10 and receives air blown in by the blower 14. The outlet of the Venturi tube 32 is the mixed gas outlet 323. A gas inlet 322 is formed at the throat 325 of the Venturi tube 32, which is connected to the gas passage 20 to receive gas input. The gas introduced at the throat 325 and the air input from the air inlet 321 are thoroughly mixed to form a mixed gas, which is then output from the mixed gas outlet 323 to the combustion chamber 40.

[0034] like Figure 3As shown, the regulating member 34 is positioned within the diverging section of the venturi tube 32, downstream of the throat 325. The regulating member 34 has a radial dimension extending perpendicular to the central axis A, which can form a barrier to the air / gas mixture within the venturi tube 32. Furthermore, the regulating member 34 can reciprocate along the central axis of the venturi tube 32, moving toward or away from the throat 325. The closer the regulating member 34 is to the throat 325, the narrower the annular gap between the regulating member 34 and the inner wall of the venturi tube 32, thereby increasing the velocity of the air flowing through this gap. Figure 3 The condition in which the regulating member 34 is tightly pressed against the throat 325 is shown. This is an extreme position in which the air flow can hardly pass. Figure 4 The following example shows a situation where the regulating member 34 is positioned away from the throat 325. The further the regulating member 34 moves away from the throat 325, the larger the annular gap between the regulating member 34 and the interior of the Venturi tube 32. This increases the flow rate of air flowing through this gap while decreasing the flow velocity. Thus, the regulating member 34 can change the cross-sectional area of ​​gas flow in the Venturi tube by moving toward or away from the throat 325, thereby achieving flow regulation.

[0035] like Figures 2-4 As shown, in the venturi tube, air enters from the air inlet 321, and the static pressure decreases when passing through the throat 325. The gas enters the mixer 30 from the gas inlet 322 at the throat 325 to achieve initial mixing. The initial mixed airflow is then mixed again through the annular gap between the regulating component 34 and the inner wall of the venturi tube 32, and the final mixed gas is output to the combustion furnace 40 from the mixed gas outlet 323. Moving the regulating component 34 can make the flow area of ​​the annular gap change with the size of the load. In particular, when the load decreases, the regulating component moves in the direction of the airflow (towards the throat), the annular gap area decreases, and the flow rate increases, thereby maintaining a larger flow rate and flow resistance even at small flow / small load, increasing the Reynolds number, and increasing the turbulent effect, ensuring that there is also a better mixing effect when the fire in the combustion furnace is small. In addition, the above-mentioned mixer with dynamic adjustment capability can simultaneously achieve the functions of mixing and flow regulation, thereby reducing the number of mixer components and saving costs to a certain extent.

[0036] Preferably, the regulating member 34 is a tapered valve plug. Its tapered outer surface, facing the throat 325, mates with the inner surface of the venturi tube 32 near the throat 325. The tapered surface facing the airflow facilitates airflow. Furthermore, the interaction between the tapered outer surface and the inner surface of the venturi tube allows airflow to flow within a narrow gap, effectively increasing the flow rate without excessively obstructing gas flow.

[0037] like Figures 2-4The regulating member 34 shown in FIG can be placed in the venturi tube in a variety of different ways to achieve the regulation drive, and the regulating member 34 itself can also adopt a variety of different shapes. Figures 2-4 The example shown is used as an example for explanation. However, as those skilled in the art will appreciate, the driving mode and shape of the adjustment component 34 are not limited to Figures 2-4 The situation shown.

[0038] In such Figures 2-4 In the illustrated example, the adjustment component 34 has a drive mechanism 36 comprising a central shaft 361 and a transmission assembly 363. The central shaft 361 extends along a central axis direction A and is reciprocally movable along the central axis direction. The adjustment component 34 is sleeved and fixed to the central shaft 361. The adjustment component 34 moves in conjunction with the movement of the central shaft 361. The transmission assembly 363 is connected to the central shaft 361 at one end and to an actuator 60 at the other end. Driven by the actuator 60, the transmission assembly 363 is capable of causing the central shaft 361 to move.

[0039] Specifically, in Figures 2-4 In the illustrated example, the transmission assembly 363 further includes a transmission shaft 363-1 and a shifter 363-2. Driven by the actuator 60, the transmission shaft 363-1 is capable of self-rotation, i.e., rotation in a direction perpendicular to the central axis. The shifter 363-2 is connected to the transmission shaft 363-1 and the central shaft 361, respectively. The shifter 363-2 acts as a connector and a drive converter, converting the rotation (angular travel) of the transmission shaft 363-1 into linear movement (linear travel) of the central shaft 361 in the direction of the central axis.

[0040] exist Figures 2-4 In the example, the shifter 363-2 is generally U-shaped, with the bottom of the U fixedly mounted on the transmission shaft 363-1, allowing the shifter 363-2 to rotate synchronously with the transmission shaft 363-1. The shifter 363-2 has two shifter rods T, which extend in a direction perpendicular to the transmission shaft and are arranged parallel to each other and spaced apart. The two shifter rods T are arranged so that the central shaft 361 can be placed therebetween. Each shifter rod T has an elongated hole L along its length. A detachable connecting rod R is also provided at the U-shaped opening of the shifter, which is adapted to pass through the elongated holes L of the two shifter rods T and a through hole in the central shaft 361 located between the two shifter rods T. The connecting rod R is arranged substantially parallel to the axial direction of the transmission shaft 363-1. Thus, when the transmission shaft 363 - 1 rotates due to the drive of the actuator 60 , the lever portion T of the shifter 363 - 2 swings under the drive of the transmission shaft 363 - 1 , and the connecting rod R drives the central shaft 361 to move along a straight line.

[0041] Combination of the aboveFigures 2-4 The examples given describe in detail the specific structure of the mixer according to one embodiment of the present application. However, it is understood by those skilled in the art that the adjustment member of the mixer can also be non-tapered in combination with the actual application conditions. For example, the adjustment member can be a blocking member extending in a direction perpendicular to the central axis, or the adjustment member can also be a semi-spherical or other shape. In Figures 2-4 In the example shown, the adjustment member 34 is fixedly connected to a central shaft 361 and moves under the drive of the central shaft. Alternatively, the adjustment member 34 can be directly pushed by a straight stroke actuator without the central shaft, or the straight stroke actuator can directly push the central shaft 361. If the angular stroke actuator 60 is continued to be used, the central shaft 361 can also be driven by the actuator through gear engagement, for example, a gear is sleeved on the transmission shaft 363-2 and the central shaft 361 has a straight rack that can engage with the gear. Alternatively, the transmission assembly 363 can also be arranged outside the venturi. Alternatively, the central shaft can also be cancelled, and the adjustment member can also be supported on the inner wall of the venturi and driven adjustment can be achieved by mechanical adjustment.

[0042] Figures 2-4 The mixer shown in Figure 1 can be used in the combustion system shown in Figure 1 . The following returns to to specifically describe the combustion system with the above-mentioned mixer 30.

[0043] As shown in Figure 1 , in the post-mix combustion system 100 according to one embodiment of the present application, air enters the fan 14 through the air filter 12 and is blown into the air inlet 321 of the mixer 30 by the fan 14. Fuel gas enters the gas inlet 322 of the mixer 30 through a proportional control valve 22, and after mixing in the mixer 30, the air and fuel gas enter the head of the combustion furnace from the mixed gas outlet 323. In the combustion furnace, the igniter ignites to make the mixed combustible gas burn. In Figure 1 the example shown, the combustion controller 50 can adjust the gas flow according to its pre-set parameters (such as load parameters), that is, by controlling the actuator 60 to drive the adjustment member 34 to move forward and backward, to adjust the amount of air and fuel gas while ensuring uniform mixing.

[0044] Preferably, the combustion system 100 further comprises a sensor 72 arranged in the combustion furnace. The sensor 72 can detect the temperature and / or pressure in the combustion furnace. The output of the sensor 72 is connected to the combustion controller 50. The combustion controller 50 adjusts the flow size according to the data sensed by the sensor, that is, by controlling the actuator 60 to drive the adjustment member 34 to move forward and backward, to automatically adjust the amount of air and fuel gas while ensuring uniform mixing.

[0045] AsFigure 1 As shown, the combustion system 100 preferably also includes a proportional control valve 22, one side of which is connected to the air passage 10 to obtain the air pressure in the air passage, and the other side is connected to the gas passage 20 to obtain the gas pressure in the gas passage. The proportional control valve 22 is capable of maintaining a constant pressure difference between the air and gas sides. In other words, when the air flow in the air passage decreases, the proportional control valve 22 can adjust the pressure on the gas side accordingly, thereby maintaining a highly accurate air-fuel ratio.

[0046] Specifically, preferably, on the air side, the proportional control valve 22 detects the difference between the total pressure at the air inlet inside the mixer 30 and the static pressure at the throat of the venturi tube. On the gas side, the proportional control valve 22 obtains the gas pressure difference before and after the gas single valve 24 in the gas channel. The proportional control valve 22 maintains the equality of the differential pressures on the air and gas sides through a diaphragm mechanical structure, thereby ensuring a constant air-fuel ratio. Even if the air side is blocked, the air-fuel ratio can be automatically maintained without the need for a compensation device. This diaphragm mechanical structure achieves pressure differential balance, is simple in structure, responds quickly and reliably, is simple to control, and is highly safe. Optionally, the proportional control valve can also be replaced with an electronic differential pressure control device that simultaneously detects the air and gas pressures. After receiving the signal, the differential pressure control device adjusts the opening of the air valve and the gas valve.

[0047] Preferably, the combustion system 100 further includes an ionization probe 74 placed in the combustion furnace for flame detection, which can sense whether flameout occurs and output the sensing result to the combustion controller 50. The combustion controller 50 can control the delivery of the mixed gas based on the sensing result fed back by the ionization probe.

[0048] Preferably, the combustion system 100 further includes an air pressure sensor 76 disposed near the blower 14 to sense air pressure changes and thereby determine whether the blower is operating. The air pressure sensor 76 is also connected to the combustion controller 50 to suspend subsequent ignition operations and restart the blower 14 if the blower 14 fails to operate normally.

[0049] More preferably, the combustion system 100 further includes a human-machine panel 90 , which is connected to the combustion controller 50 , so as to facilitate the operator to obtain the current working status and control the combustion system through the human-machine panel 100 .

[0050] The above Figure 1The shown combustion system 100, due to the use of the mixer with the adjusting component, the post-premix combustion system can adjust the flow according to the load size. When the combustion furnace is in small fire, the air and gas flow is small, at this time the adjusting component will move to the flow direction (towards the throat), to reduce the gas flow area, increase the gas flow rate and resistance, improve the mixing effect, so that the adjustment ratio reaches a higher value (for example greater than 5:1). When the combustion furnace is in large fire, the air and gas flow is large, at this time the adjusting component will move to the flow direction (away from the throat), to increase the gas flow area, reduce the gas flow rate and resistance, improve the mixing effect, so that the adjustment ratio remains at a higher value (for example greater than 5:1).

[0051] Generally, the gas pressure and the air pressure should be substantially equivalent to facilitate the pre-mixing of the gas and air in the mixer. In the above-mentioned combustion system 100, the inside of the mixer 30 is a Venturi scaling structure. With this structure, when the air flows through the mixer 30, due to the decrease of the gas flow area at the throat, the air flow rate increases, the dynamic pressure increases, and the static pressure decreases. In the mixer 30, the gas enters the mixer from the low static pressure area at the throat 325 (gas inlet), at this time the gas only needs a relatively low gas supply pressure to be injected into the mixer, which is about 2Kpa lower than the conventional gas supply pressure. This is very beneficial for those applications with relatively low gas supply pressure.

[0052] In the above-mentioned combustion system, in addition to using a mixer that can automatically adjust the flow, a proportional control valve is also used to maintain a constant air-fuel ratio. The high adjustment ratio can improve the mixing effect, and the stable air-fuel ratio can maintain good complete combustion, avoiding excessive harmful emissions (such as NOx and CO) due to incomplete combustion.

[0053] The above has shown and described in detail the present application through the accompanying drawings and preferred embodiments, however, the present application is not limited to these disclosed embodiments, and as can be known by those skilled in the art based on the above-mentioned multiple embodiments, the code review means in the above-mentioned different embodiments can be combined to obtain more embodiments of the present application, and these embodiments are also within the protection scope of the present application.

Claims

1. A mixer, which is arranged in a gas combustion system to mix air and gas to form a combustible mixed gas, characterized in that: include: A venturi tube (32) having an air inlet (321), a gas inlet (322) and a mixed gas outlet (323); the venturi tube (32) has a central axis direction (A) and a throat portion (325) disposed between the air inlet (321) and the mixed gas outlet (323) along the central axis direction; the gas inlet (322) is disposed at the throat portion (325); An adjusting component (34) is provided in the venturi tube (32) and is located downstream of the throat. The adjusting component (34) can be driven to move toward or away from the throat (325) along the central axis, thereby changing the flow area of ​​the gas in the venturi tube (32). The adjusting component (34) is a conical valve plug, and its conical outer surface on the side facing the throat (325) cooperates with the inner surface of the throat (325) of the venturi tube (32).

2. The mixer according to claim 1, wherein The invention also includes a driving mechanism (36) for driving the adjusting component (34), wherein the driving mechanism (36) includes: A central shaft (361) is placed in the venturi tube (32) in a manner capable of reciprocating along the central axis direction, and the adjustment component (34) is sleeved and fixed on the central shaft (361); A transmission component (363) has one end connected to the central shaft (361) and the other end connected to an actuator (60). The transmission component (363) causes the central shaft (361) to move under the drive of the actuator (60).

3. The mixer according to claim 2, wherein The transmission assembly (363) comprises: a transmission shaft (363-1) extending in a direction perpendicular to the central axis and rotating under the drive of the actuator (60); A shaft shifter (363-2) has one end fixedly connected to the transmission shaft (363-1) and the other end connected to the central shaft (361), wherein the transmission shaft (363-1) rotates to drive the shaft shifter (363-2), and then the shaft shifter (363-2) pushes the central shaft (361) to move linearly along the central axis.

4. The mixer according to claim 3, wherein The shaft shifter (363-2) is fixedly sleeved on the transmission shaft (363-1), and the shaft shifter (363-2) extends two shifting rods (T) in a direction perpendicular to the transmission shaft (363-1). The two shifting rods (T) are spaced apart and arranged in parallel so that the central shaft (361) is suitable for being placed therebetween, and each shifting rod has a long hole (L) along its length direction. A connecting rod (R) is adapted to pass through the long holes (L) of the two shifting rod parts (T) and the through hole on the central axis (361) disposed between the two shifting rod parts (T), and the connecting rod (R) is parallel to the transmission shaft (363-1).

5. Gas combustion system, characterized in that, include: an air passage (10) in which a fan (14) is provided for blowing air; a gas channel (20) for providing gas; A mixer (30) according to any one of claims 1 to 4, wherein the air inlet (321) is connected to the air channel (10), the gas inlet (322) is connected to the gas channel (20), and the mixed gas outlet (323) is connected to a combustion furnace (40); an actuator (60) connected to the mixer (30) for driving the regulating component (34) in the mixer (30); A combustion controller (50) is connected to the actuator (60) and drives the regulating component (34) by controlling the actuator (60) to regulate the gas flow.

6. The system according to claim 5, wherein: Also included is a first sensor (72) for sensing the temperature and / or pressure in the combustion furnace, The combustion controller (50) is connected to the first sensor (72) and controls the actuator (60) in response to sensing data of the first sensor (72).

7. The system according to claim 5, wherein: It also includes a proportional control valve (22) which uses a diaphragm mechanical structure to keep the differential pressure of the air channel (10) and the differential pressure of the gas channel (20) constant in proportion.

8. The system according to claim 5, wherein: Also included is a second sensor (76) disposed at the fan (14) for sensing air velocity; The combustion controller (50) is connected to the second sensor (76) and suspends ignition and restarts the blower (14) in response to the second sensor (76).

9. The system according to claim 5, wherein: Also included is a human-machine interaction panel (90) connected to the combustion controller (50).

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