阅读说明：本技术 一种自力式热风比例调节喷嘴系统 (Self-operated hot air proportion adjusting nozzle system ) 是由 张麒麟 陈恪彬 熊昌宇 陈万福 于 2021-08-23 设计创作，主要内容包括：本发明公开了一种自力式热风比例调节喷嘴系统,包括燃烧喷嘴,燃烧喷嘴上的空气接口、燃气接口分别连接空气管道和燃气管道,燃气管道上设有空燃比例阀,空燃比例阀与空气管道之间设有压力反馈管,所述压力反馈管上设有节流装置,空气管道上设有与节流装置下游压力反馈管连通的温度补偿装置,温度补偿装置用于感受空气管道内温度变化从而改变节流装置下游压力反馈管内的气压,温度升高,节流装置下游压力反馈管内的气压降低,反之,则是节流装置下游压力反馈管内的气压升高。本发明既能采用性价比高的空燃比例阀,又能防止空燃比随空气预热温度变化而变化,确保助燃空气预热过程中空气/燃气配比的稳定。(The invention discloses a self-operated hot air proportion adjusting nozzle system which comprises a combustion nozzle, wherein an air interface and a fuel gas interface on the combustion nozzle are respectively connected with an air pipeline and a fuel gas pipeline, an air-fuel proportion valve is arranged on the fuel gas pipeline, a pressure feedback pipe is arranged between the air-fuel proportion valve and the air pipeline, a throttling device is arranged on the pressure feedback pipe, a temperature compensation device communicated with a pressure feedback pipe at the downstream of the throttling device is arranged on the air pipeline, the temperature compensation device is used for sensing the temperature change in the air pipeline so as to change the air pressure in the pressure feedback pipe at the downstream of the throttling device, the temperature is increased, the air pressure in the pressure feedback pipe at the downstream of the throttling device is reduced, and otherwise, the air pressure in the pressure feedback pipe at the downstream of the throttling device is increased. The invention can not only adopt the air-fuel proportional valve with high cost performance, but also prevent the air-fuel ratio from changing along with the change of the air preheating temperature, and ensure the stability of the air/fuel ratio in the process of preheating the combustion air.)

1. A self-operated hot air proportion adjusting nozzle system comprises a combustion nozzle (14), an air interface and a fuel gas interface on the combustion nozzle (14) are respectively connected with an air pipeline (16) and a fuel gas pipeline (15), an air-fuel proportion valve (18) is arranged on the fuel gas pipeline (15), a pressure feedback pipe (17) is arranged between the air-fuel proportion valve (18) and the air pipeline (16), the air pressure control device is characterized in that a throttling device is arranged on the pressure feedback pipe (17), a temperature compensation device (2) communicated with the pressure feedback pipe (17) at the downstream of the throttling device is arranged on the air pipeline (16), the temperature compensation device (2) is used for sensing temperature change in the air pipeline (16) so as to change the air pressure in the pressure feedback pipe (17) at the downstream of the throttling device, the temperature is increased, the air pressure in the pressure feedback pipe (17) at the downstream of the throttling device is reduced, and otherwise, the air pressure in the pressure feedback pipe (17) at the downstream of the throttling device is increased.

2. The self-operated hot air proportion regulation nozzle system according to claim 1, wherein the temperature compensation device (2) comprises a temperature sensing container and a pressure relief device, the temperature sensing container is filled with a liquid material, the lower end of the temperature sensing container is located in the air pipeline (16), the upper end of the pressure relief device is communicated with the pressure feedback pipe (17), the lower end of the pressure relief device is connected with the temperature sensing container in a sliding manner, and the liquid material in the temperature sensing container senses the temperature change in the air pipeline (16) so as to promote the pressure relief device to change the air pressure in the pressure feedback pipe (17).

3. The self-operated hot air proportion adjusting nozzle system according to claim 2, wherein the temperature sensing container is composed of a first temperature sensing container (11) and a second temperature sensing container (12), the diameter of the first temperature sensing container (11) is larger than that of the second temperature sensing container (12), the first temperature sensing container (11) is located on the upper surface of the second temperature sensing container (12) and communicated with the second temperature sensing container (12), the second temperature sensing container (12) is located in the air pipeline (16), the first temperature sensing container (11) is located outside the air pipeline (16), and the lower end of the pressure relief device is connected with the first temperature sensing container (11) in a sliding matching manner and the connection position is sealed.

4. The self-operated hot air proportion regulation nozzle system according to claim 3, wherein the pressure relief device comprises a pressure relief box (3), a spring, an inverted triangular cone (5), a piston (7) and a connecting rod (6), the upper end of the pressure relief box (3) is communicated with a pressure feedback pipe (17), the lower end of the pressure relief box is provided with a through hole (10), the larger end of the inverted triangular cone (5) is positioned in the pressure relief box (3), the smaller end of the inverted triangular cone downwards penetrates through the through hole (10) and extends to the outside of the pressure relief box (3), the up-and-down movement of the inverted triangular cone (5) changes the conduction or the blockage of air flow at the through hole (10), the spring is positioned in the pressure relief box (3), one end of the spring acts on the top surface of the larger end of the inverted triangular cone (5), the other end of the spring acts on an annular pressing plate (13) in the pressure relief box (3), the annular pressing plate (13) is matched with the inner cavity of the pressure relief box (3), the smaller end of the inverted triangular cone (5) is fixedly connected with one end of the connecting rod (6), the other end of the connecting rod (6) is connected with a piston (7), and the piston (7) is arranged in the first temperature sensing container (11) in a sliding way.

5. The self-operated hot air proportion regulation nozzle system according to claim 4, wherein the inverted triangular cone (5) is made of rubber.

6. The self-operated hot air proportion adjusting nozzle system according to claim 2, wherein the first temperature sensing container (11) and the second temperature sensing container (12) are both made of cylindrical metal.

7. The self-operated hot air proportional regulating nozzle system according to claim 6, wherein the metal is aluminum.

8. The self-operated hot air proportion regulation nozzle system according to claim 1, wherein the throttling device is a reducing port (1) arranged in the pressure feedback pipe (17), and an air flow passage in the middle of the reducing port (1) is smaller than an air inlet end passage and an air outlet end passage.

9. The self-operated hot air proportional regulating nozzle system according to claim 1, wherein the liquid material is mercury.

10. A self-operated hot air proportional control nozzle system according to claim 4, wherein the pressure feedback tube (17) is in communication with the through hole (10).

Technical Field

The invention relates to the technical field of nozzles, in particular to a self-operated hot air proportion adjusting nozzle system.

Background

The air-fuel proportional valve is self-operated equipment with the highest neutral-price ratio and the most stable air-fuel ratio in the gas heating process, the basic working principle is that the downstream gas pressure of the air-fuel proportional valve is ensured to be consistent with the feedback pressure of combustion air through the up-and-down movement of a diaphragm, the proportional valve diaphragm can be stable only when the following equation is established in the working process of the proportional valve, otherwise the proportional valve diaphragm can move towards the direction with small acting force when the acting force on the upper surface and the lower surface of the proportional valve is different, and simultaneously drives a triangular cone to move towards the same direction, so that the area of a through-flow circular seam on the proportional valve is changed, the through-flow capacity of the proportional valve is changed, as shown in fig. 4 and 5, the downstream pressure P1 of the proportional valve is finally changed until the equation is established again. P2+ P3 ═ P1, where P1-the combustion air feedback pressure, P2-the gas pressure downstream of the proportional valve, P3-the preload pressure of the spring (this pressure is small, only a few micro-adjustments can be made)

However, in many industrial sites, the flue gas waste heat is recovered for the purpose of energy saving, wherein the most common flue gas waste heat recovery method is to preheat combustion air through flue gas, so that the flue gas temperature is reduced and then discharged, and the combustion air is heated to a certain temperature and then is input to a burner to be mixed with fuel gas and combusted. The energy-saving effect of the waste heat recovery mode is very obvious, but the air-fuel ratio is very difficult to control by adopting the high-cost-performance proportional valve in the mode, because the volume of the preheated combustion-supporting air expands, the pressure of the preheated air increases under the same mass flow, namely P1 increases, according to the proportional valve principle, P2 also increases correspondingly, P2 increases, which means larger gas flow, the gas is excessive, the preheating temperature of the combustion-supporting air is higher, and the excessive gas is more; the condition of excessive gas is a dangerous working condition in the conventional industrial combustion field, has huge potential safety hazard, and must be stopped.

Disclosure of Invention

The invention aims to provide a self-operated hot air proportion adjusting nozzle system which can not only adopt an air-fuel proportion valve with high cost performance, but also prevent the air-fuel ratio from changing along with the change of air preheating temperature and ensure the stability of air/fuel gas ratio in the process of preheating combustion air.

In order to solve the technical problem, the invention adopts the following scheme:

the utility model provides a hot-blast proportion of self-reliance adjusts nozzle system, includes combustion nozzle, and air connection, gas connection on the combustion nozzle connect air conduit and gas pipeline respectively, are equipped with air-fuel proportional valve on the gas pipeline, are equipped with the pressure feedback pipe between air-fuel proportional valve and the air conduit, be equipped with throttling arrangement on the pressure feedback pipe, be equipped with the temperature compensation device with throttling arrangement downstream pressure feedback pipe intercommunication on the air conduit, thereby temperature compensation device is used for perceiving the interior temperature variation of air conduit and changes the atmospheric pressure in the throttling arrangement downstream pressure feedback pipe, and the temperature risees, and the atmospheric pressure in the throttling arrangement downstream pressure feedback pipe reduces, otherwise, then the atmospheric pressure in the throttling arrangement downstream pressure feedback pipe risees. Compared with the prior art, the volume can expand after combustion air carries out the heat exchange in prior art, and under the same mass flow, pressure can increase after the air preheats, and combustion air's feedback pressure can increase promptly, and according to the principle of air-fuel proportional valve, the gas pressure of air-fuel proportional valve low reaches also can corresponding increase, and the pressure increase of low reaches gas means bigger gas flow, and the gas can be surplus, and combustion air preheats the temperature and is higher, and the gas surplus is more. In the scheme, after the combustion air in the air pipeline is preheated, the volume of the combustion air with the same mass flow expands, the pressure is increased, meanwhile, the heat of the combustion air is transferred to the temperature compensation device, the temperature compensation device senses the temperature rise in the air pipeline so as to reduce the air pressure in the downstream pressure feedback pipe of the throttling device, thus, the pressure at the pressure taking point of the air feedback pressure obtained by the air-fuel proportional valve is reduced, when the temperature of the combustion air is reduced, the air pressure in the downstream pressure feedback pipe of the throttling device is increased, the air feedback pressure obtained by the air-fuel proportional valve is closer to the pressure at the pressure taking point, when the temperature is reduced to the normal temperature, the pressure on the downstream pressure feedback pipe of the throttling device is not reduced, the air feedback pressure obtained by the air-fuel proportional valve is completely equal to the pressure at the pressure taking point, and thus, through the cooperative work of the throttling device and the temperature compensation device, when the temperature of the combustion air changes, the system automatically carries out self-operated temperature compensation on the air feedback pressure of the air-fuel proportional valve, so that the air-fuel ratio of the system is ensured to be stable, the condition of excessive gas is avoided, and the potential safety hazard is reduced.

Preferably, the temperature compensation device comprises a temperature sensing container and a pressure relief device, the temperature sensing container is filled with a liquid material, the lower end of the temperature sensing container is located in the air pipeline, the upper end of the pressure relief device is communicated with the pressure feedback pipe, the lower end of the pressure relief device is connected with the temperature sensing container in a sliding mode, and the liquid material in the temperature sensing container senses the temperature change in the air pipeline so as to enable the pressure relief device to change the air pressure in the pressure feedback pipe.

Preferably, the temperature sensing container is composed of a first temperature sensing container and a second temperature sensing container, the diameter of the first temperature sensing container is larger than that of the second temperature sensing container, the first temperature sensing container is located on the upper surface of the second temperature sensing container and communicated with the second temperature sensing container, the second temperature sensing container is located in the air pipeline, the first temperature sensing container is located outside the air pipeline, and the lower end of the pressure relief device is connected with the first temperature sensing container in a sliding matching mode and the joint of the pressure relief device is sealed.

Preferably, pressure relief device includes the pressure release box, a spring, the inverted triangle awl, piston and connecting rod, pressure release box upper end and pressure feedback pipe switch-on, the lower extreme is equipped with the through-hole, the great end of inverted triangle awl is located the pressure release box, less end passes the through-hole downwards and extends to the outside of pressure release box, the reciprocating of inverted triangle awl changes switching on or blocking of through-hole department air current, the spring is located the pressure release box and one end acts on the great end top surface of inverted triangle awl, the other end acts on the annular clamp plate in the pressure release box, annular clamp plate and the interior chamber matching of pressure release box, the less end of inverted triangle awl and connecting rod one end fixed connection, the connecting rod other end and piston connection, the piston slides and locates in the first temperature sensing container. When the combustion air is at normal temperature, the annular pressure plate is pressed downwards by the spring under the action of air pressure, the inverted triangular cone completely seals the through hole, so that the air in the pressure taking pipe does not flow, no pressure drop is generated at the downstream of the throttling device, and the air feedback pressure obtained by the air-fuel proportional valve is the combustion air pressure at the feedback pressure taking point;

after combustion air preheats, the combustion air of equal mass flow increases at the pressure that the pressure point department formed is got in the feedback, the heat passes through the temperature sensing container casing and conducts the liquid for in the container simultaneously, liquid temperature risees, the volume expansion, the piston rebound, reverse triangle awl moves up in step, make the through-hole have the area that switches on, reverse triangle awl can effectively change the area that the air current circulates, the air in the air feedback pipe flows into the atmosphere from the through-hole, because the air flow in the air feedback pipe, produce the pressure drop downstream throttling arrangement, thereby make the air feedback pressure that air-fuel ratio valve department obtained to get the pressure of pressure point department low.

When the temperature of combustion air is reduced, liquid in the temperature sensing container contracts, the inverted triangular cone moves downwards under the action of the spring, the conduction area of the through hole is reduced, the flow rate in the air feedback pipe is reduced, the pressure drop generated by the throttling device is also reduced, the air feedback pressure obtained by the air-fuel proportional valve is also closer to the pressure of a pressure taking point, when the temperature is reduced to normal temperature, the through hole is sealed by the inverted triangular cone, the flow rate does not exist in the air feedback pipe, the pressure drop does not exist downstream of the throttling device, the air feedback pressure obtained by the air-fuel proportional valve is completely equal to the pressure of the pressure taking point, so that the air-fuel ratio of the system is stable, the condition of gas excess cannot occur, and the potential safety hazard is reduced.

Preferably, the inverted triangular cone is made of rubber. The rubber material makes the reverse triangular cone seal the through hole more closely, avoids the pressure in the pressure feedback pipe of throttling arrangement low reaches to change.

Preferably, the first temperature sensing container and the second temperature sensing container are both made of cylindrical metal materials.

Preferably, the metal is aluminum. The heat conductivity coefficient of the aluminum is very high, so that the heat transfer speed of the temperature sensing container is high, the temperature in the air pipeline can be quickly transferred to the liquid material in the temperature sensing container, and the adjustment of the air pressure in the pressure feedback pipe by the temperature compensation device can be quickly realized.

Preferably, the throttling device is a reducing opening arranged in the pressure feedback pipe, and an air flow channel in the middle of the reducing opening is smaller than the air inlet end and the air outlet end.

Preferably, the liquid material is mercury. The boiling point of mercury is high, heat can be absorbed quickly, and the piston is forced to move up and down by expansion with heat and contraction with cold.

Preferably, the pressure feedback tube is in communication with the through hole. So that the air flow in the air feedback pipe is realized, and the pressure drop is generated above the reducing port.

The invention has the following beneficial effects:

1. the reducing port is arranged on the air feedback pipe of the proportional valve, the obtained air feedback pressure of the proportional valve after air preheating is compensated through the pressure loss change of the reducing port under different air flow rates, the air feedback pressure obtained by the proportional valve under the combustion air preheating working condition and the normal temperature air working condition is basically unchanged, and therefore the stability of the air-fuel ratio of the proportional valve under the combustion air preheating working condition is ensured.

2. The air velocity in the air feedback pipe is adjusted by utilizing the thermal expansion and cold contraction performance of the liquid material and combining the method of changing the cross section area of the gas circulation flow by the inverted triangular cone, so that the reducing port on the air feedback pipe generates different pressure drops when the temperature of combustion air changes.

3. Through the cooperative work of the reducing port and the temperature compensator, when the temperature of combustion air changes, the system automatically performs self-operated temperature compensation on the air feedback pressure of the proportional valve, and the air-fuel ratio of the system is ensured to be stable.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural diagram of a temperature compensation device;

FIG. 3 is a schematic view of a portion of the enlarged structure at A in FIG. 1;

FIG. 4 is a prior art nozzle system for an air/fuel ratio valve;

fig. 5 is a schematic structural view of the air-fuel ratio valve.

Reference numerals: 1-reducing port, 2-temperature compensation device, 3-pressure relief box, 4-Tahuang, 5-inverted triangular cone, 6-connecting rod, 7-piston, 8-liquid material, 9-pressure taking point, 10-through hole, 11-first temperature sensing container, 12-second temperature sensing container, 13-annular pressure plate, 14-combustion nozzle, 15-gas pipeline, 16-air pipeline, 17-pressure feedback pipe and 18-air-fuel ratio valve.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited to these examples.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inner", "outer", "front", "rear", "top", "bottom", and the like indicate orientations or positional relationships that are based on the orientations or positional relationships shown in the drawings, or that are conventionally placed when the product of the present invention is used, and are used only for convenience in describing and simplifying the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the invention.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "open," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example 1

As shown in fig. 1-2, a self-operated hot air proportion adjusting nozzle system includes a combustion nozzle 14, an air interface and a gas interface on the combustion nozzle 14 are respectively connected to an air pipeline 16 and a gas pipeline 15, the gas pipeline 15 is provided with an air-fuel proportion valve 18, a pressure feedback pipe 17 is provided between the air-fuel proportion valve 18 and the air pipeline 16, the pressure feedback pipe 17 is provided with a throttling device, the air pipeline 16 is provided with a temperature compensation device 2 communicated with the pressure feedback pipe 17 downstream of the throttling device, the temperature compensation device 2 is used for sensing temperature change in the air pipeline 16 so as to change air pressure in the pressure feedback pipe 17 downstream of the throttling device, the temperature is increased, the air pressure in the pressure feedback pipe 17 downstream of the throttling device is decreased, otherwise, the air pressure in the pressure feedback pipe 17 downstream of the throttling device is increased. Compared with the prior art, the volume can expand after combustion air carries out the heat exchange in prior art, and under same mass flow, the air preheats back pressure and can increase, and combustion air's feedback pressure can increase promptly, and according to the principle of air-fuel proportional valve 18, the gas pressure of air-fuel proportional valve 18 low reaches also can corresponding increase, and the pressure increase of low reaches gas means bigger gas flow, and the gas can be excessive, and combustion air preheats the temperature and is higher, and the gas is excessive.

In this embodiment, after the heat exchanger is added at the upstream of the air duct 16 and the combustion air is preheated, the volume of the combustion air with the same mass flow rate is expanded, the pressure is increased, meanwhile, the heat of the combustion air is transferred to the temperature compensation device 2, the temperature compensation device 2 senses the temperature rise in the air duct 16 so as to reduce the air pressure in the pressure feedback pipe 17 at the downstream of the throttling device, so that the pressure at the pressure taking point 9 of the air feedback pressure obtained by the air-fuel proportional valve 18 is reduced, when the temperature of the combustion air is reduced, the air pressure in the pressure feedback pipe 17 at the downstream of the throttling device is increased, the air feedback pressure obtained by the air-fuel proportional valve 18 is also closer to the pressure at the pressure taking point 9, when the temperature is reduced to normal temperature, there is no pressure drop in the pressure feedback pipe 17 at the downstream of the throttling device, the air feedback pressure obtained by the air-fuel proportional valve 18 is completely equal to the pressure at the pressure taking point 9, therefore, through the cooperative work of the throttling device and the temperature compensation device 2, when the temperature of combustion air changes, the system automatically carries out self-operated temperature compensation on the air feedback pressure of the air-fuel proportional valve 18, the air-fuel ratio of the system is ensured to be stable, the condition of excessive gas is avoided, and the potential safety hazard is reduced.

Example 2

As shown in fig. 1-3, the temperature compensation device 2 includes a temperature sensing container and a pressure relief device, the temperature sensing container is filled with a liquid material, and the lower end of the temperature sensing container is located in the air duct 16, the temperature sensing container is made of aluminum, the thermal conductivity of aluminum is very high, so that the heat transfer speed of the temperature sensing container is high, the temperature in the air duct 16 can be rapidly transferred to the liquid material in the temperature sensing container, and the adjustment of the temperature compensation device 2 to the air pressure in the pressure feedback tube 17 can be rapidly realized, the upper end of the pressure relief device is communicated with the pressure feedback tube 17, the lower end of the pressure relief device is connected with the temperature sensing container in a sliding manner, and the liquid material in the temperature sensing container senses the temperature change in the air duct 16, so that the pressure relief device changes the air pressure in the pressure feedback tube 17.

The temperature sensing container is composed of a first temperature sensing container 11 and a second temperature sensing container 12 which are cylindrical, the diameter of the first temperature sensing container 11 is larger than that of the second temperature sensing container 12, the first temperature sensing container 11 is located on the upper surface of the second temperature sensing container 12 and communicated with the second temperature sensing container 12, the second temperature sensing container 12 is located in an air pipeline 16, the first temperature sensing container 11 is located outside the air pipeline 16, and the lower end of a pressure relief device is connected with the first temperature sensing container 11 in a sliding matching mode and the connection position of the pressure relief device is subjected to sealing treatment.

The pressure relief device comprises a pressure relief box 3, a spring, an inverted triangular cone 5, a piston 7 and a connecting rod 6, wherein the upper end of the pressure relief box 3 is communicated with a pressure feedback pipe 17, the lower end of the pressure relief box is provided with a through hole 10, the pressure feedback pipe 17 is communicated with the through hole 10, so that gas flow is realized in an air feedback pipe, pressure drop is generated above a reducing hole 1, the larger end of the inverted triangular cone 5 is positioned in the pressure relief box 3, the smaller end of the inverted triangular cone 5 downwards penetrates through the through hole 10 to extend to the outside of the pressure relief box 3, the up-and-down movement of the inverted triangular cone 5 changes the communication or blocking of the air flow at the through hole 10, the inverted triangular cone 5 is made of rubber, the rubber material enables the inverted triangular cone 5 to seal the through hole 10 more tightly, the pressure in the pressure feedback pipe 17 at the downstream of the throttling device is prevented from changing, the spring is positioned in the pressure relief box 3, one end of the spring acts on the top surface of the larger end of the inverted triangular cone 5, the other end acts on an annular pressing plate 13 in the pressure relief box 3, the annular pressing plate 13 is matched with the inner cavity of the pressure relief box 3, the smaller end of the inverted triangular cone 5 is fixedly connected with one end of the connecting rod 6, the other end of the connecting rod 6 is connected with the piston 7, and the piston 7 is slidably arranged in the first temperature sensing container 11. When the combustion air is at normal temperature, the annular pressure plate 13 is pressed downwards under the action of air pressure to enable the spring to press the inverted triangular cone 5 downwards, the inverted triangular cone 5 completely seals the through hole 10, so that air in the pressure taking pipe does not flow, no pressure drop is generated at the downstream of the throttling device, and the air feedback pressure obtained by the air-fuel ratio valve 18 is the combustion air pressure at the feedback pressure taking point 9.

The working principle of the invention is as follows:

when the combustion air is at normal temperature, the inverted triangular cone 5 is pressed downwards by the spring, the through hole 10 on the pressure relief box 3 is completely sealed by the inverted triangular cone 5 (the conduction area of the through hole 10 and the external atmosphere is 0), so that the air in the pressure feedback pipe 17 does not flow, no pressure drop is generated on the reducing port 1 (or delta P is 0), and the air feedback pressure obtained by the proportional valve is the combustion air pressure at the feedback pressure taking point 9;

after the combustion air is preheated, the pressure formed by the combustion air with the same mass flow at the feedback pressure taking point 9 is increased, meanwhile, the heat is conducted to the liquid in the aluminum container through the aluminum container shell, the temperature of the liquid is increased, the volume is expanded, the piston 7 moves upwards, the inverted triangular cone 5 moves upwards synchronously, the through hole 10 in the pressure relief box 3 forms a conduction area, the air in the air feedback pipe flows into the atmosphere from the conduction area, and due to the flow of the gas in the pressure feedback pipe 17, a pressure drop delta P is generated on the reducing port 1, so that the feedback pressure of the air obtained at the air-fuel ratio valve 18 is lower than the pressure at the pressure taking point 9 by delta P.

When the temperature of combustion air is reduced, liquid in the aluminum container contracts, the inverted triangular cone 5 moves downwards under the action of the spring, the conduction area of the through hole 10 in the pressure relief box 3 is reduced, the flow rate in the pressure feedback pipe 17 is reduced, the pressure drop generated on the reducing port 1 is also reduced, the air feedback pressure obtained by the air-fuel ratio valve 18 is also closer to the pressure at the pressure taking point 9 (when the temperature is reduced to the normal temperature, the conduction area at the through hole 10 is 0, the flow rate in the pressure feedback pipe 17 is also reduced to 0, no pressure drop exists on the reducing port 1, and the air feedback pressure obtained by the air-fuel ratio valve 18 is completely equal to the pressure at the pressure taking point 9).

After the shape of the cylindrical container and the liquid material in the cylindrical container are selected, the taper of the inverted triangular cone 5 is properly selected, the corresponding relation between the area of the through hole 10 on the pressure relief box 3 for conducting the atmosphere and the stroke of the piston 7 caused by the temperature rise of the preheated air is well controlled, and the pressure rise value at the pressure taking point 9 caused by the temperature rise of the combustion-supporting air can be equal to or close to the pressure drop value delta P generated at the reducing port 1 under the temperature of the combustion-supporting air, so that the feedback pressure of the combustion-supporting air obtained by the air-fuel ratio valve 18 can not change due to the temperature change of the combustion-supporting air under the condition of certain mass flow of the combustion-supporting air, and the stability of the air/gas ratio in the combustion-supporting air preheating process is ensured.

The foregoing is only a preferred embodiment of the present invention, and the present invention is not limited thereto in any way, and any simple modification, equivalent replacement and improvement made to the above embodiment within the spirit and principle of the present invention still fall within the protection scope of the present invention.