Nitrogen spray apparatus and method

Abstract

The application discloses a nitrogen spraying device and method. The device comprises a nitrogen supply mechanism and a spraying mechanism. The spraying mechanism is connected with the gas outlet end of the nitrogen supply mechanism. The nitrogen supply mechanism is used for generating and conveying nitrogen to the spraying mechanism. The nitrogen supply mechanism comprises, along a gas conveying path, an air compressor, a water-gas separator, a cold dryer, a nitrogen generator and a curing furnace in sequence. The air compressor is used for providing compressed air. The water-gas separator is used for removing water from the compressed air. The cold dryer is used for freeze-drying the compressed air. The nitrogen generator is used for separating nitrogen from the dried air. The curing furnace is used for heating the nitrogen. The method is realized by using the above device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of spray production, in particular to a nitrogen gas spraying device and method. BACKGROUND

[0002] Spraying process is a surface treatment technology that forms a protective, decorative or other functional coating on the surface of an object by spraying paint onto the surface. Among them, nitrogen gas spraying process as an improved technology, using high-purity nitrogen gas instead of traditional compressed air as the carrier of paint, can effectively reduce the oxygen content in the spraying process and reduce the oxidation reaction between paint and workpiece. However, the existing nitrogen gas spraying technology still has many deficiencies in actual application: first, the temperature control of nitrogen gas in the delivery process is not accurate, which leads to unstable spraying effect; second, nitrogen gas will absorb a lot of heat during spraying, causing the surface temperature of the workpiece to drop sharply, which seriously affects the adhesion performance of the coating; third, the existing equipment lacks a pretreatment system for nitrogen gas, which cannot effectively remove the moisture and impurities in compressed air, affecting the purity of nitrogen gas and the spraying quality. In addition, the traditional equipment has a simple structure and lacks a stable control device for nitrogen gas pressure, resulting in large pressure fluctuations during spraying, which affects the uniformity of spraying. SUMMARY

[0003] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes a nitrogen gas spraying device and method, which has the advantages of improving the temperature control accuracy of nitrogen gas, enhancing the adhesion performance of the coating, and improving the purity of nitrogen gas.

[0004] In a first aspect, the nitrogen gas spraying device according to the embodiments of the present application comprises a nitrogen gas supply mechanism and a spraying mechanism, the spraying mechanism is connected with the gas outlet end of the nitrogen gas supply mechanism, and the nitrogen gas supply mechanism is used to generate and transport nitrogen gas to the spraying mechanism. The nitrogen gas supply mechanism comprises an air compressor, a water-gas separator, a cold dryer, a nitrogen generator and a solidification furnace arranged in sequence along the gas delivery path, the air compressor is used to provide compressed air, the water-gas separator is used to remove water from the compressed air, the cold dryer is used to freeze and dry the compressed air, the nitrogen generator is used to separate nitrogen gas from the dry air, and the solidification furnace is used to heat the nitrogen gas.

[0005] The nitrogen spraying device according to the embodiment of the present application has at least the following beneficial effects: the nitrogen supply path including an air compressor, a water-gas separator, a cold dryer, a nitrogen generator and a curing furnace is constructed, high-purity nitrogen is generated, and the nitrogen is heated at the same time to offset the temperature drop caused by heat absorption of the nitrogen during spraying. The air compressor provides initial compressed air, the water-gas separator removes liquid water in the compressed air through physical separation, the cold dryer further reduces the humidity of the gas through freeze drying to ensure that the air input into the nitrogen generator is in a low-moisture state, thereby improving the nitrogen separation efficiency. After the high-purity nitrogen is separated from the dry air by the nitrogen generator, the curing furnace heats the nitrogen, so that the nitrogen maintains a high temperature when being delivered to the spraying mechanism, thereby avoiding the temperature drop of the workpiece surface caused by heat absorption of the nitrogen during spraying, and improving the adhesion performance of the coating. The components are arranged in sequence according to the gas processing order to form a complete process from air compression, water removal and drying, nitrogen separation to temperature regulation, and finally the stability of the spraying process is improved through the heated nitrogen carrier.

[0006] The nitrogen spraying device according to the embodiment of the present application is characterized in that a first gas storage tank is arranged between the air compressor and the water-gas separator, and the first gas storage tank is used for stabilizing the compressed air pressure.

[0007] The nitrogen spraying device according to the embodiment of the present application is characterized in that a second gas storage tank is arranged between the nitrogen generator and the curing furnace, and the second gas storage tank is used for storing the nitrogen generated by the nitrogen generator.

[0008] The nitrogen spraying device according to the embodiment of the present application is characterized in that an ionization device is arranged between the second gas storage tank and the curing furnace, and the ionization device is used for ionizing the nitrogen.

[0009] The nitrogen spraying device according to the embodiment of the present application is characterized in that the ionization device is a corona discharge ionizer.

[0010] The nitrogen spraying device according to the embodiment of the present application is characterized in that the water-gas separator is a cyclone separation type structure, and a spiral flow channel for generating rotational centrifugal motion of the gas is arranged in the water-gas separator.

[0011] The nitrogen spraying device according to the embodiment of the present application further includes a temperature control device, the temperature control device includes a temperature sensor arranged at the outlet of the curing furnace and a PID controller connected with the temperature sensor, and the PID controller is used for regulating the heating power of the curing furnace to stabilize the output temperature of the nitrogen of the curing furnace at a preset value.

[0012] In a second aspect, the nitrogen spraying method according to the embodiment of the present application includes the following steps: S1: providing compressed air by an air compressor; S2: the compressed air is sequentially subjected to water removal by a water-gas separator and drying by a cold dryer; S3: Pass the dried compressed air into the nitrogen generator to obtain nitrogen; S4: Pass the generated nitrogen gas into a curing oven at a constant temperature of 75°C and heat it to 53°C; S5: Nitrogen gas at 53°C is delivered to the spraying mechanism to perform coating operations on the workpiece.

[0013] The nitrogen spraying method according to embodiments of the present invention has at least the following beneficial effects: This application establishes a staged temperature-controlled nitrogen treatment process, which, while maintaining the low oxidation advantage of nitrogen spraying, specifically addresses adhesion defects caused by low temperatures. In step S1, compressed air generated by an air compressor is used as the basic gas source to provide stable gas pressure conditions for subsequent nitrogen preparation; in step S2, a dual dehumidification mechanism is formed through the series processing of a water-air separator and a refrigerated dryer to ensure the dryness of the compressed air and avoid the influence of moisture on subsequent nitrogen production processes and coating quality; in step S3, high-purity nitrogen is separated from the dry air by a nitrogen generator to establish the core conditions of an inert gas environment; in step S4, a curing oven at a constant temperature of 75°C is innovatively set to precisely heat the nitrogen to 53°C, which avoids the gas expansion caused by high temperature affecting the spraying atomization effect, and compensates for the temperature drop caused by nitrogen heat absorption by moderately raising the temperature; in step S5, the temperature-optimized nitrogen is applied to the spraying operation, and the bonding strength between the coating and the substrate is improved while maintaining low oxygen content through precise control of temperature parameters. Each step forms a temperature gradient control chain, ensuring nitrogen purity through pre-drying treatment and balancing temperature loss through post-heating treatment, ultimately achieving dual optimization of spraying quality.

[0014] According to the nitrogen spraying equipment of the present invention, in step S2, compressed air first enters the first gas storage tank for pressure stabilization, and then enters the water-gas separator; And / or, After step S3 and before step S4, the generated nitrogen gas is stored in the second gas storage tank.

[0015] According to an embodiment of the present invention, the nitrogen spraying equipment further includes the step of passing nitrogen into an ionization device for ionization treatment after storing nitrogen in a second gas storage tank and before passing it into a curing oven.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of a nitrogen spraying device according to an embodiment of the present invention; Figure 2 This is a flowchart of a nitrogen spraying method according to an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: Air compressor 100; Water-air separator 200; Refrigerated dryer 300; Nitrogen generator 400; Curing oven 500; First gas storage tank 600; Second gas storage tank 700; Ionization device 800. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0021] In the description of the invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. If the terms "first" and "second" are used, they are only for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0022] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0023] In existing technologies, nitrogen spraying processes use high-purity nitrogen instead of compressed air as the coating carrier, which can reduce oxygen content and decrease oxidation reactions. However, in practical applications, nitrogen absorbs heat during spraying, leading to a decrease in workpiece surface temperature and reduced coating adhesion. This problem is particularly prominent in coating scenarios involving precision instruments or temperature-sensitive materials, where workpiece surface temperature fluctuations directly affect coating uniformity and bonding strength. Existing technologies lack effective means of controlling nitrogen temperature, making it difficult to balance the dual requirements of oxidation control and temperature maintenance.

[0024] To address the aforementioned issues, analysis revealed that the temperature drop caused by nitrogen's heat absorption is a key factor affecting adhesion. Traditional solutions often focus on improving coating formulations or optimizing spraying parameters, failing to fundamentally solve the temperature problem. Based on thermodynamic principles, this study explores introducing a heating element into the nitrogen delivery process to compensate for heat loss during spraying by increasing the initial nitrogen temperature. Through system design, a heating device was placed at the end of the nitrogen generation process, avoiding the impact of high temperatures on nitrogen generation efficiency while ensuring that the nitrogen reaches a suitable temperature before being delivered to the spraying mechanism.

[0025] Therefore, referring to Figure 1 This invention provides a nitrogen spraying device. Specifically, the nitrogen spraying device includes a nitrogen supply mechanism and a spraying mechanism. The spraying mechanism is connected to the outlet of the nitrogen supply mechanism. The nitrogen supply mechanism generates and delivers nitrogen to the spraying mechanism. The nitrogen supply mechanism includes an air compressor 100, a water-air separator 200, a refrigerated dryer 300, a nitrogen generator 400, and a curing oven 500 arranged sequentially along the gas delivery path. The air compressor 100 provides compressed air and removes water from the compressed air. The refrigerated dryer 300 freeze-dries the compressed air. The nitrogen generator 400 separates nitrogen from the dried air. The curing oven 500 heats the nitrogen.

[0026] Among them, air compressor 100 refers to a device that compresses ambient air to form high-pressure gas, specifically using a piston or screw compressor. It increases gas pressure through mechanical work, providing a power source for subsequent processing. Water-air separator 200 refers to a device that removes liquid water from compressed air through physical means, specifically using a cyclone separator structure. It utilizes centrifugal force to achieve gas-liquid separation, preventing moisture from entering subsequent equipment. Refrigerated dryer 300 refers to a device that lowers the gas temperature through a refrigeration cycle, specifically using a combination of evaporator and condenser, further removing water vapor from the gas through freeze drying. Nitrogen generator 400 refers to a device that extracts nitrogen from air through adsorption or membrane separation technology, specifically using a pressure swing adsorption system, utilizing molecular sieves to selectively adsorb oxygen components. Curing oven 500 refers to a closed cavity that heats the gas, specifically using a combination of resistance heating tubes and insulation layers, with a temperature control module maintaining a stable nitrogen output temperature.

[0027] Specifically, compressed air is pressurized by air compressor 100, then passes through water-air separator 200 to remove liquid water, and then through refrigerated dryer 300 to lower the gas dew point, ensuring that the air entering nitrogen generator 400 is in a low-humidity state. Nitrogen generator 400 separates high-purity nitrogen from the dry air and introduces it into curing oven 500 for heating treatment. The heated nitrogen is then transported through pipelines to the spraying unit, where a suitable temperature is maintained during spraying to offset the temperature drop caused by the heat absorption of nitrogen expansion. The entire gas treatment path forms a continuous process of compression, dehumidification, nitrogen generation, and temperature control, with a temperature compensation mechanism ensuring stable workpiece surface temperature during spraying.

[0028] Compared to existing technologies, traditional nitrogen spraying equipment typically only includes a nitrogen generation module and lacks a temperature control device, or it uses post-spraying heating of the workpiece, resulting in high energy consumption and delayed temperature control. This solution achieves simultaneous temperature compensation and spraying operation by directly heating the nitrogen after generation, avoiding additional energy consumption and ensuring real-time temperature control.

[0029] Through the above technical solution, this application effectively solves the problem of workpiece surface temperature drop caused by gas heat absorption during nitrogen spraying. The heated nitrogen carrier maintains a stable temperature in the spraying area, improving the adhesion strength between the coating and the substrate. The integrated design of the gas treatment process ensures nitrogen purity while achieving temperature control, enhancing the stability and applicability of the spraying process.

[0030] According to some embodiments of this application, a first air storage tank 600 is provided between the air compressor 100 and the water-air separator 200. The first air storage tank 600 is used to stabilize the compressed air pressure.

[0031] The first air storage tank 600 refers to a sealed container with a specific volume, which can be made of welded carbon steel and equipped with a pressure gauge and a safety valve. Its internal cavity is used to temporarily store the compressed air output by the air compressor 100. Through the volume buffering effect, it can absorb instantaneous pressure fluctuations during gas transportation.

[0032] Specifically, the air compressor 100 experiences pressure fluctuations in its output air due to periodic exhaust or load changes during operation. A first air storage tank 600 is located downstream of the air compressor 100. When the output pressure of the air compressor 100 increases instantaneously, excess gas is stored in the tank; when the pressure decreases, the stored gas is released to replenish the flow. Through this dynamic balance of gas storage and release, the compressed air pressure entering the water-air separator 200 is maintained within a stable range. This pressure regulation method avoids the decrease in separation efficiency of the cyclone separation structure inside the water-air separator 200 due to airflow impact, while simultaneously providing stable air intake conditions for the refrigerated dryer 300, ensuring a continuous supply of stable pressure dry air to the subsequent nitrogen generator 400.

[0033] Compared to existing technologies, in traditional nitrogen spraying equipment, the air compressor 100 is directly connected to the water-air separator 200. Fluctuations in compressed air pressure can easily cause turbulent airflow inside the water-air separator 200, reducing dewatering efficiency. This solution adds a first air storage tank 600, utilizing its volume buffering characteristics to actively regulate air pressure, fundamentally eliminating the negative impact of pressure fluctuations on subsequent equipment.

[0034] Through the above technical solution, this application can effectively suppress pressure pulsation during compressed air transportation, ensure that the water-air separator 200, the refrigerated dryer 300 and the nitrogen generator 400 operate under constant pressure conditions, avoid equipment performance fluctuations caused by sudden changes in air pressure, and thus improve the stability and continuity of the nitrogen preparation process.

[0035] According to some embodiments of this application, a second gas storage tank 700 is provided between the nitrogen generator 400 and the curing oven 500, and the second gas storage tank 700 is used to store nitrogen generated by the nitrogen generator 400.

[0036] The second gas storage tank 700 refers to a gas storage container located downstream of the nitrogen generator 400. It can be implemented as a pressure vessel or a buffer tank, and its internal volume is sufficient to hold the amount of nitrogen produced by the nitrogen generator 400 per unit time. By storing the nitrogen output from the nitrogen generator 400, this storage tank can buffer fluctuations in the nitrogen generator 400's gas production, preventing sudden changes in gas pressure in subsequent process stages due to insufficient or excessive instantaneous gas production from the nitrogen generator 400.

[0037] The storage of nitrogen generated by nitrogen generator 400 refers to the temporary storage of nitrogen continuously output by nitrogen generator 400 through the buffering effect of a gas storage tank. Specifically, dynamic balance can be achieved by adjusting the opening of the inlet and outlet valves of the gas storage tank. This storage process decouples the gas delivery path between nitrogen generator 400 and curing oven 500, so that the nitrogen supply to curing oven 500 is not affected by fluctuations in nitrogen generator 400 production.

[0038] Specifically, the nitrogen generator 400 may experience fluctuations in nitrogen production during operation due to changes in the adsorbent regeneration cycle or compressed air input. The second gas storage tank 700 temporarily stores nitrogen, accumulating excess gas when the nitrogen generator 400's production exceeds the curing oven 500's requirements, and releasing the stored gas when production is insufficient, thus maintaining a constant nitrogen flow rate and pressure entering the curing oven 500. The buffering effect of the storage tank ensures that the heating power of the curing oven 500 can stably act on the constant flow of nitrogen, avoiding temperature changes caused by gas flow fluctuations. Therefore, the nitrogen temperature received by the spraying mechanism remains uniform, and the problem of decreased coating adhesion on the workpiece surface due to temperature fluctuations is solved.

[0039] Compared to existing technologies, current nitrogen spraying equipment typically connects the nitrogen generator 400 directly to the curing oven 500 without an intermediate gas storage tank. When the nitrogen generator 400's output fluctuates, the inlet pressure of the curing oven 500 changes accordingly, leading to unstable nitrogen temperature after heating. This solution introduces a second gas storage tank 700, dividing the gas delivery path between the nitrogen generator 400 and the curing oven 500 into two independently controlled stages. Fluctuations in the nitrogen generator 400's output are absorbed by the storage tank, ensuring the curing oven 500 always receives a stable flow of nitrogen, thus guaranteeing accurate temperature control.

[0040] Through the above technical solution, this application can eliminate the influence of nitrogen generator 400 gas production fluctuations on the temperature stability of curing oven 500, so that nitrogen gas maintains a uniform temperature distribution during heating, and avoids the reduction of coating adhesion on the workpiece surface due to nitrogen gas temperature fluctuations during spraying.

[0041] According to some embodiments of this application, an ionization device 800 is provided between the second gas storage tank 700 and the curing oven 500, and the ionization device 800 is used to ionize nitrogen gas.

[0042] Among them, the ionization device 800 refers to a device that ionizes gas molecules through the action of an electric field. Specifically, it can be implemented by a corona discharge ionizer, which generates an ionization region through a high-voltage electrode, so that nitrogen molecules acquire an electric charge.

[0043] The arrangement between the second gas storage tank 700 and the curing oven 500 refers to placing the ionization device 800 in the gas delivery pipeline between the outlet of the gas storage tank and the inlet of the curing oven 500. This position allows the nitrogen gas to undergo ionization treatment after storage and stabilization, and the ionized active nitrogen gas directly enters the temperature-controlled curing oven 500.

[0044] Specifically, nitrogen gas exits from the second gas storage tank 700 and enters the ionization device 800, where some nitrogen molecules are ionized into charged particles under the influence of a high-voltage electric field. The charged nitrogen then enters the curing oven 500, where its ionized state is maintained under temperature control. During the spraying process, the charged nitrogen acts as a carrier, mixing with the paint particles. Through charge interaction, it enhances the uniformity of particle dispersion. Simultaneously, the charged nitrogen generates an electrostatic adsorption effect upon contact with the workpiece surface, improving the wettability of the paint on low-temperature surfaces. The ionized nitrogen gas maintains temperature stability in the curing oven 500, preventing the ionization effect from attenuating due to temperature fluctuations.

[0045] Compared to existing technologies, traditional nitrogen spraying processes do not ionize nitrogen gas and rely solely on temperature control to improve adhesion. This solution, however, introduces a charge effect through an ionization device 800, enhancing the adhesion between the coating and the substrate at a physicochemical level. In existing technologies, if ionization is involved, the ionization device 800 is typically placed near the spraying mechanism, but the synergistic effect of nitrogen storage and temperature control is not considered. This results in the ionized nitrogen losing its activity due to long-distance transport or temperature changes.

[0046] Through the above technical solution, this application solves the problem of reduced coating adhesion caused by low temperature during nitrogen spraying. By ionization treatment, nitrogen carries a charge, which enhances the dispersion uniformity of coating particles and the electrostatic adsorption effect on the workpiece surface. At the same time, combined with the temperature control of the curing oven 500, the stability of the ionization effect is maintained, thereby improving the coating adhesion strength.

[0047] Preferably, the ionization device 800 is a corona discharge ionizer. Specifically, after nitrogen gas enters the corona discharge ionizer, in the high-voltage electric field formed between the needle-shaped electrode and the plate-shaped electrode, gas molecules are accelerated and ionized by collisions with high-energy electrons, generating uniformly distributed charged ions. The ionization intensity is controlled in real time by a voltage regulation module, for example, using a 0-30kV adjustable DC power supply, so that the nitrogen ionization efficiency matches the requirements of the spraying process. The ionized nitrogen gas carries a charge and enters the spraying mechanism. Under the action of the electric field force, the charged paint particles are more uniformly adsorbed onto the workpiece surface, overcoming the problem of decreased adhesion at low temperatures.

[0048] Furthermore, the water-gas separator 200 of this application has a cyclone separation structure, and the interior of the water-gas separator 200 is provided with a spiral flow channel that causes the gas to generate a rotating centrifugal motion.

[0049] It is understandable that a cyclone separator structure refers to a device that uses the centrifugal force generated by the rotational motion of gas to achieve gas-liquid separation. Specifically, it can be implemented using a cylindrical structure with a tangential air inlet and an axial exhaust pipe. The tangential air inlet causes the gas to form a swirling flow within the cylinder. The spiral flow channel refers to a channel structure located inside the separator that guides the gas along a spiral trajectory. Specifically, it can be implemented using guide plates or spiral blades that continuously extend around the central axis, thereby enhancing the centrifugal separation effect by extending the gas flow path.

[0050] Specifically, compressed air enters the water-air separator 200 and is tangentially guided into the cylinder, forming a high-speed rotating airflow under the guidance of the spiral flow channel. Denser liquid water particles in the gas are thrown against the inner wall of the cylinder by centrifugal force, accumulating along the wall and being discharged through the bottom drain. The dry gas then enters the subsequent processing stage from the top outlet. The spiral flow channel increases the number of gas rotations, allowing moisture to be fully separated over a longer path, eliminating the need for filter media interception and avoiding the efficiency reduction problem caused by filter media clogging in traditional filter-type separators.

[0051] Compared to existing technologies, traditional water-air separation methods often employ multi-stage filtration or adsorption materials to intercept moisture, resulting in drawbacks such as frequent filter replacement, high operating costs, and susceptibility to clogging. This solution, however, utilizes physical centrifugal separation to achieve continuous and efficient water removal without consumables. The separation efficiency is unaffected by fluctuations in moisture content, and the maintenance cycle is significantly extended.

[0052] Through the above technical solution, this application effectively improves the dehydration efficiency of compressed air, ensuring that the moisture content of the gas entering the refrigerated dryer 300 and nitrogen generator 400 is reduced to a lower level, thereby avoiding the impact of residual moisture on the purity of nitrogen production and ensuring that the final nitrogen quality meets the requirements of the spraying process.

[0053] According to some embodiments of this application, the temperature control device includes a temperature sensor disposed at the outlet of the curing oven 500 and a PID controller connected thereto. The PID controller is used to regulate the heating power of the curing oven 500 so that the output nitrogen temperature of the curing oven 500 can be stabilized at a preset value. The temperature sensor is a sensing element used to detect gas temperature, specifically a thermocouple or a resistance temperature detector (RTD). Its placement at the outlet of the curing oven 500 allows for direct measurement of the actual temperature of the output nitrogen, avoiding measurement deviations caused by pipeline heat dissipation or environmental interference. The PID controller is a closed-loop control device based on proportional, integral, and derivative operations. Specifically, it can be implemented using a programmable controller with analog input / output functionality. By receiving feedback signals from the temperature sensor in real time and comparing them with the preset temperature value, it generates an adjustment signal to dynamically adjust the heating power of the curing oven 500.

[0054] Specifically, the temperature sensor transmits the detected nitrogen temperature signal to the PID controller. The PID controller, based on the deviation between the preset temperature value and the actual temperature, rapidly responds to temperature fluctuations through proportional calculations, eliminates steady-state errors through integral calculations, and predicts temperature change trends through derivative calculations. These three functions work together to output a control signal to the heating element of the curing oven 500. The heating power is dynamically adjusted according to the control signal; for example, the power output increases when the detected temperature is lower than the preset value, and decreases when it is higher, thus forming a closed-loop regulation circuit to continuously maintain the nitrogen temperature within the preset range.

[0055] Compared to existing technologies, traditional spraying equipment typically employs open-loop temperature control, relying solely on preset heating power for unidirectional control. This approach cannot compensate for temperature drift caused by changes in ambient temperature or fluctuations in gas flow in real time. In contrast, this solution combines closed-loop control with a PID algorithm to proactively correct temperature deviations and suppress the impact of external disturbances on nitrogen temperature, overcoming the hysteresis and insufficient adjustment precision inherent in open-loop control. Through the above technical solution, this application can accurately control the nitrogen temperature output by the curing oven 500, avoid the nitrogen absorbing too much heat during the spraying process due to temperature fluctuations, thereby reducing the surface temperature of the workpiece, effectively improving the adhesion strength between the coating and the workpiece, and ensuring the stability of the spraying quality.

[0056] Furthermore, the conveying pipe between the curing oven 500 and the spraying mechanism is covered with thermal insulation material.

[0057] Reference Figure 2 The present invention also provides a nitrogen spraying method, which is implemented by using the nitrogen spraying equipment described above.

[0058] Specifically, the nitrogen spraying method includes the following steps: S1: Compressed air is supplied via air compressor 100; S2: Compressed air passes sequentially through a water-air separator 200 to remove water and a refrigerated dryer 300 to dry it. S3: The dried compressed air is passed into the nitrogen generator 400 to produce nitrogen; S4: The generated nitrogen gas is introduced into a curing oven 500 at a constant temperature of 75°C and heated to 53°C; S5: Nitrogen gas at 53°C is delivered to the spraying mechanism to perform coating operations on the workpiece.

[0059] It is understandable that the 75℃ curing oven 500 refers to a heating device with temperature maintenance function, which can be achieved by using an electric heating element in conjunction with an insulation layer structure, for stable heating of nitrogen. Heating to 53℃ refers to raising the nitrogen temperature to a specific range, which can be achieved by adjusting the heating power in conjunction with a temperature sensor and controller to balance the temperature drop caused by nitrogen absorbing heat. The water-air separator 200 removes water, which is the process of removing liquid moisture from compressed air, which can be achieved by using a cyclone separator structure, separating moisture through the centrifugal force generated by gas rotation. The refrigerated dryer 300 further reduces the humidity of compressed air, which can be achieved by using a refrigerant circulation cooling method, removing gaseous moisture through condensation.

[0060] Specifically, after compressed air is generated by air compressor 100, it first enters water-air separator 200 for preliminary dehydration, where liquid water is separated and discharged by centrifugal force. Then, it enters refrigerated dryer 300 for deep drying, where gaseous water condenses into liquid at low temperature and is discharged. The dried compressed air then enters nitrogen generator 400, where oxygen is separated by molecular sieve adsorption to obtain high-purity nitrogen. The nitrogen then enters a temperature-controlled curing oven 500, where it undergoes heating treatment at a preset temperature. For example, the power of the heating element is adjusted by a PID controller to stably raise the nitrogen temperature to the target value. The heated nitrogen is then delivered to the spraying mechanism, where it atomizes the coating while maintaining the surface temperature of the workpiece, preventing a decrease in coating adhesion due to nitrogen heat absorption.

[0061] Compared to existing technologies, traditional nitrogen spraying methods do not actively regulate nitrogen temperature, leading to a decrease in workpiece surface temperature and affecting coating adhesion. This method adds a 500°C heating stage to the curing oven, specifically compensating for heat loss during the spraying process while maintaining an inert nitrogen environment. Simultaneously, a staged temperature control strategy is employed to avoid gas expansion caused by high temperatures affecting atomization while ensuring the nitrogen temperature remains within the optimized range.

[0062] Through the above technical solution, this application effectively solves the problem of workpiece surface temperature drop caused by gas heat absorption during nitrogen spraying. While maintaining low oxygen content to inhibit coating oxidation, temperature compensation improves the adhesion strength between the coating and the substrate. The synergistic effect of drying and heating treatment ensures the dual stability of nitrogen purity and spraying temperature, thereby obtaining a more uniform and dense coating structure.

[0063] Furthermore, in step S2, the compressed air first enters the first gas storage tank 600 for pressure stabilization, and then enters the water-gas separator 200; and / or, after step S3 and before step S4, the generated nitrogen is stored in the second gas storage tank 700.

[0064] Specifically, compressed air is first introduced into the first gas storage tank 600 before entering the water-gas separator 200. The internal volume of the tank buffers gas pressure fluctuations, making the inlet pressure of the subsequent water-gas separator 200 more stable and preventing a decrease in gas-liquid separation efficiency due to sudden pressure changes. The nitrogen generated by the nitrogen generator 400 is temporarily stored in the second gas storage tank 700 before entering the curing oven 500. When the gas production rate of the nitrogen generator 400 is lower than the consumption demand of the curing oven 500, the storage tank releases stored gas to supplement the supply gap; when the gas production rate is higher than the consumption demand, the excess gas is stored to maintain system pressure stability, thereby achieving dynamic matching between nitrogen supply and heating demand.

[0065] In some specific embodiments, the volume of the first air storage tank 600 can be 3-5 times the discharge volume of the air compressor 100 per minute, and the inlet and outlet pipe diameters can be set to 1.2-1.5 times that of the main compressed air pipeline. The second air storage tank 700 can be equipped with a pressure sensor and interlocked with the nitrogen generator 400 for control. When the pressure inside the tank is lower than a set threshold, the nitrogen generator 400 is triggered to start replenishing air.

[0066] Compared to existing technologies, the traditional nitrogen spraying process directly connects the air compressor 100 and the water-gas separator 200. Fluctuations in compressed air pressure cause turbulent airflow within the separator, affecting dehydration efficiency. This solution eliminates pressure pulsations through a pre-positioned gas storage tank, allowing the gas-liquid separation process to proceed under steady-state conditions. In existing technologies, when the nitrogen generator 400 is directly connected to the curing oven 500, the discontinuous gas production from the nitrogen generator 400 causes temperature fluctuations within the oven exceeding ±5℃. This solution controls temperature fluctuations within ±1℃ by incorporating a buffer storage tank.

[0067] Through the above technical solutions, this application achieves pressure stability of the compressed air treatment system, enabling the water-air separator 200 to operate under constant conditions, and improving the gas-liquid separation efficiency by about 18%; at the same time, through the nitrogen buffer storage mechanism, the fluctuation rate of nitrogen flow rate at the inlet of the curing oven 500 is reduced from the original 15% to less than 3%, improving the surface temperature uniformity of the sprayed workpiece and enhancing the coating adhesion.

[0068] Furthermore, after storing nitrogen in the second gas storage tank 700 and before introducing it into the curing oven 500, the process includes the step of introducing nitrogen into an ionization device 800 for ionization treatment. The ionization device 800 is a device that ionizes gas molecules through an electric field; specifically, it can be implemented using a corona discharge ionizer, which generates corona discharge through high-voltage electrodes, causing nitrogen molecules to lose or gain electrons to form charged ions. The purpose of ionization treatment is to change the physical properties of nitrogen, making it carry a charge, thereby enhancing the interaction between paint particles and the workpiece surface during subsequent spraying.

[0069] Specifically, after nitrogen is stored in the second gas storage tank 700, it enters the ionization device 800 for ionization treatment. During ionization, nitrogen molecules are decomposed into charged ions. These charged ions combine with paint particles during the spraying stage, forming a charged mixed gas flow. When the charged paint particles contact the workpiece surface, the charge adsorption compensates for the weakening of intermolecular forces caused by the decrease in nitrogen temperature. After being heated in the curing oven 500, the ionized nitrogen remains charged, enhancing the adhesion between the paint and the substrate during spraying through charge attraction.

[0070] Compared to existing technologies, traditional nitrogen spraying processes do not ionize nitrogen gas and rely solely on temperature control to improve adhesion. However, low-temperature nitrogen gas still suffers from poor charge distribution uniformity. This solution ionizes nitrogen gas to carry a controllable charge, utilizing the charge adsorption effect to directly enhance the adhesion between the coating and the workpiece, thus overcoming the limitations of relying solely on temperature control.

[0071] Through the above technical solution, this application effectively solves the problem of decreased adhesion to the workpiece surface due to temperature reduction during nitrogen spraying. Ionized nitrogen enhances the bonding strength between coating particles and the substrate through charge adsorption, maintaining stable coating adhesion even at low temperatures, while avoiding energy waste caused by excessive heating of nitrogen.

[0072] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0073] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A nitrogen spraying device, comprising a nitrogen supply mechanism and a spraying mechanism, wherein the spraying mechanism is connected to the outlet end of the nitrogen supply mechanism, and the nitrogen supply mechanism is used to generate and supply nitrogen to the spraying mechanism, characterized in that: The nitrogen supply mechanism includes an air compressor, a water-air separator, a refrigerated dryer, a nitrogen generator, and a curing oven arranged sequentially along the gas transport path. The air compressor is used to provide compressed air, the water separator is used to remove water from the compressed air, the refrigerated dryer is used to freeze-dry the compressed air, the nitrogen generator is used to separate nitrogen from the dried air, and the curing oven is used to heat the nitrogen.

2. The nitrogen spraying equipment according to claim 1, characterized in that, A first air storage tank is provided between the air compressor and the water-air separator. The first air storage tank is used to stabilize the compressed air pressure.

3. The nitrogen spraying equipment according to any one of claims 1 or 2, characterized in that, A second gas storage tank is provided between the nitrogen generator and the curing oven, and the second gas storage tank is used to store the nitrogen generated by the nitrogen generator.

4. The nitrogen spraying equipment according to claim 3, characterized in that, An ionization device is provided between the second gas storage tank and the curing oven, and the ionization device is used to ionize nitrogen gas.

5. The nitrogen spraying equipment according to claim 4, characterized in that, The ionization device is a corona discharge ionizer.

6. The nitrogen spraying equipment according to claim 1, characterized in that, The water-gas separator is a cyclone separator structure, and its interior is equipped with a spiral flow channel that causes the gas to rotate and centrifugally.

7. The nitrogen spraying equipment according to claim 1, characterized in that, It also includes a temperature control device, which includes a temperature sensor installed at the outlet of the curing oven and a PID controller connected thereto. The PID controller is used to regulate the heating power of the curing oven so that the nitrogen output temperature of the curing oven can be stabilized at a preset value.

8. A nitrogen spraying method, implemented using the nitrogen spraying equipment according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1: Compressed air is supplied via an air compressor; S2: Compressed air passes through a water-air separator to remove water and then through a refrigerated dryer for drying. S3: Pass the dried compressed air into the nitrogen generator to obtain nitrogen; S4: Pass the generated nitrogen gas into a curing oven at a constant temperature of 75°C and heat it to 53°C; S5: Nitrogen gas at 53°C is delivered to the spraying mechanism to perform coating operations on the workpiece.

9. The nitrogen spraying method according to claim 8, characterized in that, In step S2, compressed air first enters the first air storage tank for pressure stabilization, and then enters the water-air separator; And / or, After step S3 and before step S4, the generated nitrogen gas is stored in the second gas storage tank.

10. The nitrogen spraying method according to claim 8, characterized in that, After storing nitrogen in the second gas storage tank and before passing it into the curing oven, the process also includes the step of passing nitrogen into an ionization device for ionization treatment.

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