阅读说明：本技术 一种用于镀锌/铝气刀的氮气空气混和系统 (Nitrogen and air mixing system for zinc/aluminum plating air knife ) 是由 李文 于 2021-06-23 设计创作，主要内容包括：本发明提供了一种用于镀锌/铝气刀的氮气空气混和系统,包括制氮机、第一输氮管、空压机、第一供气管和混和气控制系统,制氮机通过第一输氮管与混和气控制系统相连,空压机通过第一供气管与混和气控制系统相连,混和气控制系统通过第一混和气管与气刀相连,混和气控制系统用于调控氮气和空气的混和情况,混和气控制系统包括第一气动控制器、第一压力调节阀、第二气动控制器、第二压力调节阀和汇集管,第一压力调节阀设于第一输氮管上,第二压力调节阀设于第一供气管上,本发明可以在保证退火炉用氮气的情况下,能充分利用氮气站产生的富余氮气(改前全部排放),节约了成本,可利用氮气量：12000000m～3。(The invention provides a nitrogen and air mixing system for a zinc/aluminum plating air knife, which comprises a nitrogen making machine, a first nitrogen conveying pipe, an air compressor and a first nitrogen conveying pipeAir supply pipe and gas mixing control system, the nitrogen generator links to each other with gas mixing control system through first defeated nitrogen pipe, the air compressor machine links to each other with gas mixing control system through first air supply pipe, gas mixing control system links to each other with the air knife through first mixed gas pipe, gas mixing control system is used for regulating and controlling the mixed condition of nitrogen gas and air, gas mixing control system includes first pneumatic controller, first pressure regulating valve, second pneumatic controller, second pressure regulating valve and header, first pressure regulating valve locates on first defeated nitrogen pipe, second pressure regulating valve locates on first air supply pipe, the invention can be under the condition of guaranteeing the nitrogen gas for the annealing furnace, the abundant nitrogen gas that the ability make full use of nitrogen gas station produced (discharge all before changing), and the cost is saved, usable nitrogen gas volume: 12000000m 3 。)

1. A nitrogen air mixing system for a zinc/aluminum plating air knife, characterized by: including nitrogen generator (10), first defeated nitrogen pipe (20), air compressor machine (30), first air supply pipe (40) and thoughtlessly admit air control system (50), nitrogen generator (10) through first defeated nitrogen pipe (20) with thoughtlessly admit air control system (50) link to each other, air compressor machine (30) pass through first air supply pipe (40) with thoughtlessly admit air control system (50) link to each other, thoughtlessly admit air control system (50) link to each other with air knife (70) through first mixed trachea (60), thoughtlessly admit air control system (50) are used for the mixed condition of regulation and control nitrogen gas and air.

2. A nitrogen air mixing system for a zinc/aluminum plating air knife according to claim 1 wherein: the gas mixing and mixing control system (50) comprises a first pneumatic controller (51), a first pressure regulating valve (52), a second pneumatic controller (53), a second pressure regulating valve (54) and a collecting pipe (55), wherein the first pressure regulating valve (52) is arranged on the first nitrogen conveying pipe (20), the first pneumatic controller (51) is used for controlling the opening and closing condition of the first pressure regulating valve (52), the second pneumatic controller (53) is used for controlling the opening and closing condition of the second pressure regulating valve (54), and the second pressure regulating valve (54) is arranged on the first gas supply pipe (40).

3. A nitrogen air mixing system for a zinc/aluminum plating air knife according to claim 2 wherein: one end of the first pneumatic controller (51) is connected with the front end of the first nitrogen conveying pipe (20), the other end of the first pneumatic controller (51) is connected with the first pressure regulating valve (52), and the first pneumatic controller (51) is used for acquiring a pressure signal at the front end of the pipeline of the first nitrogen conveying pipe (20);

one end of the second pneumatic controller (53) is connected with the first mixed gas pipe (60), the other end of the second pneumatic controller (53) is connected with the second pressure regulating valve (54), and the second pneumatic controller (53) is used for acquiring a pressure signal in a pipeline of the first mixed gas pipe (60).

4. A nitrogen air mixing system for a zinc/aluminum plating air knife according to claim 2 wherein: the first pressure regulating valve (52) and the second pressure regulating valve (54) are respectively provided with a positioner (56) and an actuator (57), the first pneumatic controller (51) and the second pneumatic controller (53) are respectively connected with the positioners (56) on the first pressure regulating valve (52) and the second pressure regulating valve (54), the first pneumatic controller (51) and the second pneumatic controller (53) are respectively connected with the actuators (57) on the first pressure regulating valve (52) and the second pressure regulating valve (54) through instrument air pipes (58), and the actuators (57) are used for controlling the corresponding first pressure regulating valve (52) or the corresponding second pressure regulating valve (54).

5. A nitrogen-air mixing system for a zinc/aluminum plating air knife according to claim 4 wherein: one end of the instrument air pipe (58) close to the first pneumatic controller (51) or the second pneumatic controller (53) is provided with a two-stage pressure reducer (59), and one end of the instrument air pipe (58) close to the actuator (57) is provided with a pressure reducer (591).

6. A nitrogen air mixing system for a zinc/aluminum plating air knife according to claim 2 wherein: the first nitrogen conveying pipe (20) is provided with at least two one-way valves (21) between the first pressure regulating valve (52) and the collecting pipe (55) so as to prevent gas in the collecting pipe (55) from flowing back to the front end of the first nitrogen conveying pipe (20), an oxygen content detector (22) is arranged between the nitrogen making machine (10) and the first pressure regulating valve (52) of the first nitrogen conveying pipe (20), and the oxygen content detector (22) is used for detecting oxygen content information in the first nitrogen conveying pipe (20).

7. A nitrogen air mixing system for a zinc/aluminum plating air knife according to claim 1 wherein: all be equipped with flowmeter (80) and manometer (90) on first nitrogen transmission pipe (20) and first air supply pipe (40), flowmeter (80) are used for monitoring gas flow information in first nitrogen transmission pipe (20) or first air supply pipe (40), manometer (90) are used for monitoring gas pressure information in first nitrogen transmission pipe (20) or first air supply pipe (40).

8. A nitrogen air mixing system for a zinc/aluminum plating air knife according to claim 2 wherein: the first mixed gas pipe (60) is connected with the diffusing pipe (62) through a second mixed gas pipe (61), the first gas supply pipe (40) is connected with the diffusing pipe (62) through a second gas supply pipe (41), and ball valves are arranged on the second mixed gas pipe (61) and the second gas supply pipe (41).

9. A nitrogen air mixing system for a zinc/aluminum plating air knife according to claim 1 wherein: the nitrogen making machine (10) is connected with the annealing furnace (24) through a second nitrogen conveying pipe (23), the nitrogen making machine (10) is directly connected with the air knife (70) through a third nitrogen conveying pipe (25), and ball valves are arranged on the second nitrogen conveying pipe (23) and the third nitrogen conveying pipe (25).

10. A nitrogen air mixing system for a zinc/aluminum plating air knife according to claim 1 wherein: the air compressor (30) is connected with the galvanized/aluminum unit (43) through a third air supply pipe (42), and a ball valve is arranged on the third air supply pipe (42).

Technical Field

The invention relates to the technical field of strip steel production, in particular to a nitrogen and air mixing system for a zinc/aluminum plating air knife.

Background

The TKASCQ galvanizing line has two products of galvanizing and aluminizing, redundant zinc/aluminum liquid on the surface of strip steel needs to be blown off by an air knife, and the air knife generally uses two media: (1) air: a fan directly generates normal-pressure air, the air knife sweeps the surface of the strip steel, a 7-grade plate with lower surface quality requirement is produced, the power of the fan is 400KW, but the surface quality is poorer, and the complaint rate of customers is higher; (2) pure nitrogen: pure nitrogen is provided by a nitrogen making machine of a nitrogen station, strip steel is blown by an air knife, high surface quality requirements such as 3-grade plates (O5 plates) are produced, products between 3-7-grade plates are produced, the requirements of users are met, the high generation and the low use are achieved, pure nitrogen is used for production, and the investment cost is high.

The basic load of a nitrogen making machine (supplying air to a galvanizing air knife) at a nitrogen-hydrogen station is 3400m³About/h nitrogen, except for ensuring the annealing furnace (average 1600 m)³H) use, average about 1700m³The surplus nitrogen gas of/h and above is discharged into the air, which is wasted. If the air knife is charged with pure nitrogen, it is usually 2700m³Once the dosage of the annealing furnace is increased, liquid nitrogen is added for a long time, so the consumption cost is high. Meanwhile, the air compression station supplies compressed air to the unit by about 1400-1600m³Per, rated flow of single air compressor is 2000m³And h, 3 air compressors are used in total, and if 1 air compressor is started, the requirement of the unit is met.

At this point, the nitrogen generator is preliminarily calculated to be rich in residual nitrogen (about 1700 m)³H and above), in addition start 2 air compressors, mix two kinds of gas together, both satisfied annealing stove and unit with the gas outward, still can satisfy air knife gas consumption, but has several difficult points and risks:

(1) on the premise of meeting the requirements of an annealing furnace and a unit, the annealing furnace and the unit are mixed together;

(2) even if they can be mixed together, there is a risk of affecting the quality of the board surface once the mixing is not uniform;

(3) the difference between the oxygen content (about 21%) of the compressed air and the oxygen content (required to be less than or equal to 20PPM) required by the annealing furnace is large, and once oxygen in the air leaks into the annealing furnace, serious consequences are brought;

(4) and how to ensure the matching of the annealing furnace and the air knife pressure.

It is therefore desirable to provide a new nitrogen and air mixing system to solve the problems of the prior art.

Disclosure of Invention

In order to solve the technical problem, an embodiment of the present invention provides a nitrogen and air mixing system for a zinc/aluminum plating air knife, including a nitrogen generator, a first nitrogen conveying pipe, an air compressor, a first air supply pipe, and a mixing and air control system, where the nitrogen generator is connected to the mixing and air control system through the first nitrogen conveying pipe, the air compressor is connected to the mixing and air control system through the first air supply pipe, the mixing and air control system is connected to the air knife through the first mixing air pipe, and the mixing and air control system is used to regulate and control the mixing condition of nitrogen and air.

Further, mix gas control system includes first pneumatic control ware, first pressure regulating valve, second pneumatic control ware, second pressure regulating valve and manifold, first pressure regulating valve locates on the first nitrogen pipe of failing, first pneumatic control ware is used for control the condition of opening and shutting of first pressure regulating valve, second pneumatic control ware is used for controlling the condition of opening and shutting of second pressure regulating valve, second pressure regulating valve locates on the first air supply pipe.

Furthermore, one end of the first pneumatic controller is connected with the front end of the first nitrogen conveying pipe, the other end of the first pneumatic controller is connected with the first pressure regulating valve, and the first pneumatic controller is used for acquiring a pressure signal at the front end of the first nitrogen conveying pipe;

one end of the second pneumatic controller is connected with the first mixed gas pipe, the other end of the second pneumatic controller is connected with the second pressure regulating valve, and the second pneumatic controller is used for acquiring a pressure signal in the first mixed gas pipe.

Furthermore, the first pressure regulating valve and the second pressure regulating valve are respectively provided with a positioner and an actuator, the first pneumatic controller and the second pneumatic controller are respectively connected with the positioners on the first pressure regulating valve and the second pressure regulating valve, the first pneumatic controller and the second pneumatic controller are respectively connected with the actuators on the first pressure regulating valve and the second pressure regulating valve through instrument air pipes, and the actuators are used for controlling the corresponding first pressure regulating valve or the corresponding second pressure regulating valve.

Furthermore, one end of the instrument air pipe, which is close to the first pneumatic controller or the second pneumatic controller, is provided with a two-stage pressure reducer, and one end of the instrument air pipe, which is close to the actuator, is provided with a pressure reducer.

Furthermore, the first nitrogen conveying pipe is provided with at least two one-way valves between the first pressure regulating valve and the collecting pipe, so that gas in the collecting pipe is prevented from flowing back to the front end of the first nitrogen conveying pipe, an oxygen content detector is arranged between the nitrogen making machine and the first pressure regulating valve of the first nitrogen conveying pipe, and the oxygen content detector is used for detecting oxygen content information in the first nitrogen conveying pipe.

Furthermore, all be equipped with flowmeter and manometer on first nitrogen transmission pipe and the first air supply pipe, the flowmeter is used for monitoring gas flow information in first nitrogen transmission pipe or the first air supply pipe, the manometer is used for monitoring gas pressure information in first nitrogen transmission pipe or the first air supply pipe.

Further, first gas mixing pipe links to each other with the diffusion pipe through second gas mixing pipe, first gas supply pipe pass through the second gas supply pipe with the diffusion pipe links to each other, the second gas mixing pipe with all be equipped with the ball valve above the second gas supply pipe.

Furthermore, the nitrogen making machine is connected with the annealing furnace through a second nitrogen conveying pipe, the nitrogen making machine is directly connected with the air knife through a third nitrogen conveying pipe, and ball valves are arranged on the second nitrogen conveying pipe and the third nitrogen conveying pipe.

Furthermore, the air compressor is connected with the zinc/aluminum plating unit through a third air supply pipe, and a ball valve is arranged on the third air supply pipe.

The invention has the beneficial effects that:

1) the invention can fully utilize the surplus nitrogen generated by the nitrogen station (all the nitrogen is discharged before the nitrogen station is changed) under the condition of ensuring the nitrogen for the annealing furnace, thereby saving the cost, and utilizing the following nitrogen amount: 12000000m³。

2) The invention changes the mode that the prior air knife is dare not to easily throw nitrogen, and the nitrogen of the annealing furnace is not enough, and simultaneously, the invention stabilizes the pressure of the gas supply of the annealing furnace and the air knife, reduces the throw-in of liquid nitrogen, and the pressure error of the mixed gas is lower than 0.1 bar. Liquid nitrogen is saved by about 100 tons each year.

3) The nitrogen content of the gas mixed by the method is obviously increased, and the surface quality of the strip steel is obviously improved.

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram of a nitrogen-air mixing system for a zinc/aluminum plating air knife in an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a mixing and air-conditioning control system in an embodiment of the invention.

Reference numerals: 10-nitrogen making machine, 20-first nitrogen conveying pipe, 21-one-way valve, 22-oxygen content detector, 23-second nitrogen conveying pipe, 24-annealing furnace, 25-third nitrogen conveying pipe, 30-air compressor, 40-first air supply pipe, 41-second air supply pipe, 42-third air supply pipe, 43-zinc/aluminum plating unit, 50-mixed gas control system, 51-first pneumatic controller, 52-first pressure regulating valve, 53-second pneumatic controller, 54-second pressure regulating valve, 55-collecting pipe, 56-positioner, 57-actuator, 58-instrument air pipe, 59-two-stage pressure reducer, 591-pressure reducer, 60-first mixed gas pipe, 61-second mixed gas pipe, 62-diffusing pipe, 70-air knife, 80-flowmeter, 90-pressure gauge.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.

Referring to fig. 1-2, fig. 1 is a schematic structural diagram of a nitrogen-air mixing system for a zinc/aluminum plating air knife in an embodiment of the present invention, the nitrogen-air mixing system for a zinc/aluminum plating air knife includes a nitrogen generator 10, a first nitrogen pipe 20, an air compressor 30, a first air supply pipe 40, and a mixing and degassing control system 50, the nitrogen generator 10 is connected to the mixing and degassing control system 50 through the first nitrogen pipe 20, the air compressor 30 is connected to the mixing and degassing control system 50 through the first air supply pipe 40, the mixing and degassing control system 50 is connected to an air knife 70 through the first mixing and degassing pipe 60, the mixing and degassing control system 50 is configured to regulate a mixing condition of nitrogen and air, the air knife 70 is configured to blow off excessive zinc/aluminum liquid on a strip steel surface, so as to prevent the excessive zinc/aluminum liquid from depositing on the strip steel surface and causing uneven product surface coating, causing product quality defects.

In some preferred embodiments, the mixing and gas control system 50 includes a first pneumatic controller 51, a first pressure regulating valve 52, a second pneumatic controller 53, a second pressure regulating valve 54 and a collecting pipe 55, the first pressure regulating valve 52 is disposed on the first nitrogen pipe 20, the first pneumatic controller 51 is used for controlling the opening and closing of the first pressure regulating valve 52, the second pneumatic controller 53 is used for controlling the opening and closing of the second pressure regulating valve 54, and the second pressure regulating valve 54 is disposed on the first gas supply pipe 40.

In some preferred embodiments, one end of the first pneumatic controller 51 is connected to the front end of the first nitrogen input pipe 20, the other end of the first pneumatic controller 51 is connected to the first pressure regulating valve 52, and the first pneumatic controller 51 is used for acquiring a pressure signal of the front end of the first nitrogen input pipe 20;

one end of the second pneumatic controller 53 is connected to the first mixed gas pipe 60, the other end of the second pneumatic controller 53 is connected to the second pressure regulating valve 54, and the second pneumatic controller 53 is configured to obtain a pressure signal in the first mixed gas pipe 60.

In some preferred embodiments, a positioner 56 and an actuator 57 are provided on each of the first pressure regulating valve 52 and the second pressure regulating valve 54, the first pneumatic controller 51 and the second pneumatic controller 53 are respectively connected to the positioner 56 on each of the first pressure regulating valve 52 and the second pressure regulating valve 54, the first pneumatic controller 51 and the second pneumatic controller 53 are respectively connected to the actuator 57 on each of the first pressure regulating valve 52 and the second pressure regulating valve 54 through an instrument air pipe 58, and the actuator 57 is used for controlling the corresponding first pressure regulating valve 52 or the corresponding second pressure regulating valve 54.

In some preferred embodiments, a two-stage pressure reducer 59 is arranged at one end of the instrument air pipe 58 close to the first pneumatic controller 51 or the second pneumatic controller 53, and a pressure reducer 591 is arranged at one end of the instrument air pipe 58 close to the actuator 57, so that the air source pressure can be reduced to 0-2 bar, and therefore, the pneumatic control cannot be damaged due to overhigh air source pressure.

In some preferred embodiments, the first nitrogen delivery pipe 20 is provided with at least two check valves 21 between the first pressure regulating valve 52 and a header 55, thereby preventing the gas in the collecting pipe 55 from flowing back to the front end of the first nitrogen delivery pipe 20, the first nitrogen delivery pipe 20 is provided with an oxygen content detector 22 between the nitrogen generator 10 and the first pressure regulating valve 52, the oxygen content detector 22 is used for detecting the oxygen content information in the first nitrogen transmission pipe 20, in actual use, designing a check valve 21 also prevents reverse flow, but after considering a check valve 21 is damaged, the front end of the first nitrogen delivery pipe 20 is flushed with air, which affects the whole production line, so that at least two check valves 21 are provided on the line, after damage to one of the check valves 21, the other can continue to be used, leaving sufficient maintenance time for the operator.

In certain preferred embodiments, the first nitrogen delivery pipe 20 and the first gas supply pipe 40 are both provided with a flow meter 80 and a pressure gauge 90, the flow meter 80 is used for monitoring the gas flow information in the first nitrogen delivery pipe 20 or the first gas supply pipe 40, and the pressure gauge 90 is used for monitoring the gas pressure information in the first nitrogen delivery pipe 20 or the first gas supply pipe 40.

In some preferred embodiments, the first gas mixing pipe 60 is connected to a diffusing pipe 62 through a second gas mixing pipe 61, the first gas supply pipe 40 is connected to the diffusing pipe 62 through a second gas supply pipe 41, and ball valves are disposed on both the second gas mixing pipe 61 and the second gas supply pipe 41.

In some preferred embodiments, the nitrogen generator 10 is connected to the annealing furnace 24 through a second nitrogen pipe 23, the nitrogen generator 10 is directly connected to the air knife 70 through a third nitrogen pipe 25, and ball valves are disposed on the second nitrogen pipe 23 and the third nitrogen pipe 25.

In some preferred embodiments, the air compressor 30 is connected to the zinc/aluminum plating unit 43 through a third air supply pipe 42, and a ball valve is disposed on the third air supply pipe 42.

The working principle of the invention is as follows:

1. the nitrogen main pipe and the air main pipe reserved on the platform are respectively connected with the corresponding pipelines of the mixing system, and the two gases are fully mixed by the collecting pipe 55 and then are used by gas equipment. Preferably, nitrogen is used for air knife 70. When the nitrogen pressure is lower than the set pressure (5.9bar) of the gas controller, the nitrogen is supplemented by compressed air, and the process is automatically controlled, namely: the positioners 56 on the pipelines for controlling two media (nitrogen and compressed air respectively) input pressure signals respectively by a pneumatic controller so as to control the opening angle of the regulating valve. In order to prevent air from entering the upstream nitrogen pipeline, at least 1 set of wafer-type check valves are arranged on the nitrogen pipeline, so that the nitrogen upstream pipeline is ensured not to be leaked, and meanwhile, the mixed gas outlet pressure (5.0-5.1bar) is set to be lower than the set pressure of the nitrogen. When the pressure in the equipment header 55 and the pressure in the air duct exceed the set pressures, the overpressure gas is discharged outside the plant through the bleed-off pipe 62.

2. The first pneumatic controller 51 for controlling the first pressure regulating valve 52 on the nitrogen pipeline takes a pipeline pressure signal from the front end of the nitrogen pipeline and outputs the pipeline pressure signal to the positioner 56 on the nitrogen pipeline, and the positioner 56 is linked with the actuator 57, so that the opening angle of the first pressure regulating valve 52 is changed, the valve clack of the first pressure regulating valve 52 on the nitrogen pipeline is in a stable state after the regulation is finished, wherein the initial state of the valve clack of the first pressure regulating valve 52 is fully opened.

3. A second pneumatic controller 53, which controls a second pressure regulating valve 54 on the compressed air line, takes a line pressure signal from the plant mix and gas outlet line front. And outputting the output to a positioner 56 on the air pipeline, and changing the opening angle of the second pressure regulating valve 54 by the positioner 56 in linkage with an actuator 57, wherein the valve clack of the second pressure regulating valve 54 on the air pipeline is in a stable state after the regulation is finished, wherein the valve clack of the second pressure regulating valve 54 is in a fully closed state.

4. The pneumatic controller drives the air source inlet to install the two-stage pressure reducer, and the air source pressure is reduced to 0-2 bar, so that the pneumatic controller is guaranteed against being damaged due to overhigh air source pressure.

5. In practical use, the wind wheel type collecting pipe 55 is adopted, so that two gases can be fully mixed, the gas blown out by the air knife is more stable, the stable blowing of the surface coating of the strip steel by the air knife is ensured, and the phenomenon that the blowing force of each section of the strip steel is different due to insufficient mixing of the gases, and the performance of each section of the strip steel is unstable is avoided.

In the description herein, references to the description of the terms "one embodiment," "certain embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In summary, although the present invention has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, therefore, the scope of the present invention shall be determined by the appended claims.