Titanium nano coating heat exchanger

Abstract

The invention provides a titanium nano-coating heat exchanger and a coating method thereof, the titanium nano-coating heat exchanger comprises a main body and a heat exchange tube arranged in the main body, the two sides of the main body are provided with an air inlet and an air outlet respectively, and the two ends of the heat exchange tube are provided with a water inlet and a water outlet respectively; the inner wall of the main body and / or the inner wall of the air inlet and / or the inner wall of the air outlet and / or the inner wall and / or the outer wall of the heat exchange tube are / is a bottom surface, and a titanium nano coating is arranged on the bottom surface. According to the titanium nano-coating heat exchanger provided by the invention, the titanium nano-coating is arranged on the bottom surface of the heat exchanger, so that the requirement on corrosion resistance of a heat exchanger manufacturing material is reduced, the overall manufacturing cost of the heat exchanger is further reduced, and the capital investment of an enterprise is reduced. The titanium nano coating has the characteristics of compact structure and high surface smoothness, is small in friction coefficient, inhibits scaling in the heat exchanger, improves the heat exchange efficiency, has good corrosion resistance, and can prolong the service life of the heat exchanger.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and more specifically, to a titanium nano-coated heat exchanger. Background Art

[0002] In recent years, as people's awareness of environmental protection and energy conservation and consumption reduction continues to increase, my country has increasingly attached importance to flue gas waste heat recovery. By using flue gas heat to heat the circulating water in the water heating system, the heating capacity can be improved, coal consumption can be reduced, and a good energy-saving and emission-reduction effect can be achieved. In the flue gas waste heat recovery system, the heat exchanger is a necessary equipment to meet the process conditions, and it is also one of the main equipment to improve energy utilization.

[0003] Because the flue gas contains corrosive media H2S and SO x 、NO x , Cl-, F-, H+, etc., which will react chemically with the heat exchanger material under certain temperature and humidity to generate soluble salts, which will gradually corrode and damage the heat exchanger; due to the change of flue gas temperature, soluble salts will be deposited in the heat exchanger, and a dense and hard scale will be formed on the inner surface of the heat exchanger over time. Since the heat transfer coefficient of scale is extremely low, the thermal efficiency of the heat exchanger continues to decline, causing huge losses to the company.

[0004] The existing methods for solving the above problems are mainly as follows: (1) Using corrosion-resistant materials to manufacture heat exchangers, generally using expensive materials such as titanium and Hastelloy. These materials are expensive, which makes the cost of the heat exchanger too high, resulting in an increase in the overall cost of the entire system. Moreover, most of these materials have a low heat transfer coefficient, which greatly affects the heat exchange effect. (2) Using 316 stainless steel + nickel metal plating. After operation, this method has been proved to be unable to meet the requirements of flue gas corrosion resistance, and rust and blockage are serious. It needs to be replaced within two years of working time, which cannot meet the company's operation and environmental protection requirements. (3) Using nitriding technology. Although nitriding technology has good corrosion resistance, it is difficult to solve the problem of scaling and high-temperature treatment that causes the material to become more brittle.

[0005] Therefore, the problems existing in the prior art need to be further improved and developed. Summary of the invention

[0006] (I) Purpose of the invention: In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a titanium nano-coated heat exchanger and a coating method thereof.

[0007] (II) Technical solution: In order to solve the above technical problems, the present technical solution provides a titanium nano-coated heat exchanger, comprising a main body and a heat exchange tube arranged inside the main body, an air inlet and an air outlet are respectively arranged on both sides of the main body, a water inlet and a water outlet are respectively arranged at both ends of the heat exchange tube, the inner wall of the main body and / or the inner wall of the air inlet and / or the inner wall of the air outlet and / or the inner wall and / or the outer wall of the heat exchange tube are the bottom surface, the surface of the bottom surface is smooth and free of attachments, and the surface roughness of the bottom surface is 40 to 70 μm; a titanium nano-coating is arranged on the bottom surface, and the total thickness of the titanium nano-coating reaches 27 The invention discloses a titanium nano-coating having a thickness of 270 μm or more, wherein the titanium nano-coating comprises 2 layers of primer films and 4 layers of topcoat films, and the total thickness ranges from 270 μm to 300 μm. The titanium nano-coating comprises a primer layer and a topcoat layer, wherein the primer layer comprises at least two layers of primer films, and the topcoat layer comprises at least four layers of topcoat films; the components and proportions of the primer film comprise: 43% epoxy resin, 24% titanium nano-metal powder, 18% acetone, 5% curing agent, and 10% mica powder; the components and proportions of the topcoat film comprise: 63% polyurethane resin, 15% titanium nano-metal powder, 12% acetone, 4% curing agent, and 6% mica powder.

[0008] The present invention also provides a coating method for a titanium nano-coated heat exchanger, comprising the following steps:

[0009] Step 1: Clean, remove rust and roughen the bottom surface to make the surface roughness reach 40-70μm;

[0010] Step 2: Mix epoxy resin, titanium nano metal powder, acetone, curing agent and mica powder in different proportions to form a primer and a topcoat of the titanium nano polymer coating, and add a diluent;

[0011] Step 3: Apply two layers of primer and four layers of topcoat on the bottom surface in sequence and cure them to obtain a titanium nano-coated heat exchanger;

[0012] Step 4: Perform appearance inspection, thickness inspection, leakage inspection and adhesion inspection on the titanium nano-coated heat exchanger.

[0013] A method for coating a titanium nano-coated heat exchanger, wherein the step 1 specifically comprises:

[0014] Step 11: Use lye to wash the bottom surface with high pressure hot water to remove grease and dirt;

[0015] Step 12: Use quartz sand as abrasive material, add it into the sandblasting machine, and sandblast the bottom surface;

[0016] Step 13: After sandblasting, use a vacuum cleaner, dry and clean compressed air or a brush to remove dust from the bottom surface to ensure that there is no residue on the surface.

[0017] A coating method for a titanium nano-coated heat exchanger, wherein the particle sizes of the sand materials are the same or different, and the proportions of the sand materials with different particle sizes are roughly equal; and the compressed air pressure in the sand blasting machine is controlled at 0.4-0.8Mpa.

[0018] A coating method for a titanium nano-coated heat exchanger, wherein the adding of a diluent in step 2 specifically comprises: preparing the primer and the topcoat in a correct ratio, and adding a diluent not exceeding 20% ​​of the total amount to the primer and the topcoat respectively, stirring evenly and then standing for 5-10 minutes to eliminate bubbles, wherein the diluent is ethylene glycol methyl ether.

[0019] A method for coating a titanium nano-coated heat exchanger, wherein the step 3 specifically comprises the following steps:

[0020] Step 31: After the bottom surface is treated and cleaned, two coats of the primer in the titanium nano polymer coating are applied, and the interval between the coatings of the primers is 4 hours to ensure the interlayer bonding strength;

[0021] Step 32: After waiting for 4 hours and the primer is cured, four coats of the titanium nano polymer coating are applied, with each coat of topcoat applied at an interval of 4 hours, during which the bottom surface to be constructed is rotated 180 degrees to ensure uniform coating;

[0022] Step 33: After all coatings are applied, cure at room temperature for more than 7 days.

[0023] A coating method for a titanium nano-coated heat exchanger, wherein after each coating of a primer or topcoat, the appearance and thickness of the primer film or topcoat film are checked to ensure that there is no missing coating and that the thickness of each layer is uniform; when missing coating or insufficient thickness occurs, the coating is promptly supplemented; after the last primer film is completely dried and before solidification, the thickness of the primer layer is checked, and if the thickness is less than 80 μm, the number of coating layers is increased until it is qualified; after the last topcoat film is completely dried and before solidification, the thickness of the topcoat layer is checked, and if the thickness is less than 170 μm, the number of coating layers is increased until it is qualified.

[0024] A coating method for a titanium nano-coated heat exchanger, wherein the appearance inspection specifically includes visually inspecting whether the surface of the titanium nano-coating is flat and smooth, and whether there are defects such as missing coating, stickiness, peeling, bubbles and scars;

[0025] The thickness inspection specifically includes using a thickness gauge to detect the thickness of the titanium nano coating, and the thinnest point of the titanium nano coating should be ≥150 μm;

[0026] The leakage point inspection is specifically to use a 5-10 times magnifying glass to inspect, and the one without leakage points is qualified;

[0027] The adhesion test is specifically to use a knife blade to cut through the titanium nano-coating to form a V-shaped incision, and then peel off the titanium nano-coating in the incision to test its adhesion.

[0028] A coating method for a titanium nano-coated heat exchanger, wherein when performing a thickness inspection, three areas to be inspected are selected on the surface of the titanium nano-coating of the part to be inspected, and 10% of the area of ​​each area to be inspected is taken for inspection. 2 For one inspection area, at least 2 points shall be randomly inspected in each inspection area, and the points shall be evenly distributed. The number of randomly inspected points at the weld shall not be less than 30% of the total number of inspection points.

[0029] A coating method for a titanium nano-coated heat exchanger, wherein the leak inspection sampling rate is equal to or greater than 5% of the coating area, and the weak links such as the welds are inspected intensively; if the number of leaks is 1 / m 2 , repair, if the number of leaks exceeds 1 / m 2 , for comprehensive recoating.

[0030] (III) Beneficial effects: The present invention provides a titanium nano-coated heat exchanger. Since the bottom surface of the heat exchanger is provided with a titanium nano-coating, the requirements for the corrosion resistance of the heat exchanger manufacturing material are reduced, thereby reducing the overall cost of the heat exchanger and reducing the capital investment of the enterprise. The titanium nano-coating has the characteristics of dense structure, high surface smoothness, and low friction coefficient, which inhibits scaling inside the heat exchanger and improves the heat exchange efficiency. At the same time, it has good corrosion resistance and can extend the service life of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the overall structure of a titanium nano-coated heat exchanger of the present invention;

[0032] Figure 2 This is a schematic diagram of the heat exchange tube structure of a titanium nano-coated heat exchanger of the present invention;

[0033] Figure 3 This is a schematic diagram of a coating method for a titanium nano-coated heat exchanger of the present invention;

[0034] Figure Number:

[0035] 1-main body, 2-air inlet, 3-air outlet, 4-water inlet, 5-water outlet, 6-heat exchange tube, 7-liquid collecting box, 8-drain outlet, 9-titanium nano coating. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with preferred embodiments. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0037] The accompanying drawings are schematic diagrams of embodiments of the present invention. It should be noted that the drawings are only examples and are not drawn to scale, and should not be used to limit the actual protection scope of the present invention.

[0038] This technical solution provides a titanium nano-coated heat exchanger, such as Figure 1 As shown, it comprises: a main body 1 and a heat exchange tube 6 arranged inside the main body 1, an air inlet 2 and an air outlet 3 are respectively arranged on both sides of the main body 1, high-temperature flue gas enters the main body 1 from the air inlet 2, and low-temperature flue gas leaves the main body 1 from the air outlet 3, and a water inlet 4 and a water outlet 5 are respectively arranged at both ends of the heat exchange tube 6, low-temperature liquid enters the heat exchange tube 6 from the water inlet 4, and high-temperature liquid leaves the heat exchange tube 6 from the water outlet 5. When the high-temperature flue gas passes through the heat exchange tube 6, it contacts the wall surface and transfers heat to the low-temperature liquid in the heat exchange tube 6, thereby achieving the effect of heat exchange.

[0039] Preferably, in the present invention, a liquid collecting box 7 is provided inside the main body 1 and below the heat exchange tube 6, and a drain port 8 is connected below the liquid collecting box 7 for collecting and discharging condensed water generated during the heat exchange process from inside the main body 1.

[0040] Preferably, the inner wall of the main body 1 and / or the inner wall of the air inlet 2 and / or the inner wall of the air outlet 3 and / or the inner wall and / or the outer wall of the heat exchange tube 6 are provided with a titanium nano coating 9. Figure 2 As shown, the outer surface of the heat exchange tube 6 is provided with a titanium nano coating 9. The inner wall of the main body 1 and / or the inner wall of the air inlet 2 and / or the inner wall of the air outlet 3 and / or the inner wall and / or the outer wall of the heat exchange tube 6 can be called the bottom surface, and the surface of the bottom surface is smooth and free of attachments, and the surface roughness of the bottom surface is 40-70 μm.

[0041] Preferably, the titanium nano coating comprises a primer layer and a topcoat layer. The primer layer comprises at least two primer films, i.e., the primer needs to be applied at least twice, each application forms a primer film; the topcoat layer comprises at least four topcoat films, i.e., the topcoat needs to be applied at least four times, each application forms a topcoat film.

[0042] Preferably, the composition and proportion of the primer film include: epoxy resin: 43%, titanium nano-metal powder: 24%, acetone: 18%, curing agent: 5%, mica powder: 10%. The composition and proportion of the topcoat film include: polyurethane resin: 63%, titanium nano-metal powder: 15%, acetone: 12%, curing agent: 4%, mica powder: 6%.

[0043] Preferably, the thickness of the primer layer is in the range of 80 μm to 100 μm, the thickness of the topcoat layer is in the range of 170 μm to 200 μm, and the total thickness of the titanium nano-coating is in the range of 270 μm to 300 μm.

[0044] The technical solution also provides a coating method for a titanium nano-coated heat exchanger, such as Figure 3 As shown, the following steps are included:

[0045] Step 1: Clean, remove rust and roughen the bottom surface to make the surface roughness reach 40-70μm;

[0046] Step 2: Mix epoxy resin, titanium nano metal powder, acetone, curing agent and mica powder in different proportions to form a primer and a topcoat of the titanium nano polymer coating, and add a diluent;

[0047] Step 3: Apply two layers of primer and four layers of topcoat on the bottom surface in sequence and cure them to obtain a heat exchanger with a titanium nano-coating;

[0048] Step 4: For the heat exchanger with titanium nano-coating, perform appearance inspection, thickness inspection, leakage inspection and adhesion inspection.

[0049] Preferably, the step 1 of the present invention specifically comprises:

[0050] Step 11: Use alkali solution to clean the bottom surface with high pressure hot water to remove grease and dirt. The bottom surface is the inner wall of the main body 1 and / or the inner wall of the air inlet 2 and / or the inner wall of the air outlet 3 and / or the inner wall and / or outer wall of the heat exchange tube 6.

[0051] Step 12: Use quartz sand as sand material, add it into a sandblasting machine, and sandblast the bottom surface. After sandblasting, the surface roughness of the bottom surface reaches 40-70 μm, there is no visible grease, dirt, oxide scale, rust and paint coating attachment on the surface, and it shows a uniform metallic luster.

[0052] Step 13: After sandblasting, use a vacuum cleaner, dry and clean compressed air or a brush to remove dust from the bottom surface to ensure that there is no residue on the surface.

[0053] Preferably, the particle sizes of the sand materials can be the same or different, and the proportions of sand materials with different particle sizes are roughly equal; and the compressed air pressure of the sand blasting machine is controlled at 0.4-0.8Mpa.

[0054] Preferably, in the step 2, epoxy resin, titanium nano metal powder, acetone, curing agent and mica powder are mixed in different proportions to form a primer and a topcoat of the titanium nano polymer coating. The proportions of the components in the primer are: epoxy resin: 43%, titanium nano metal powder: 24%, acetone: 18%, curing agent: 5%, and mica powder: 10%. The proportions of the components in the topcoat are: polyurethane resin: 63%, titanium nano metal powder: 15%, acetone: 12%, curing agent: 4%, and mica powder: 6%.

[0055] The primer and topcoat are configured in the correct ratio, and a diluent not exceeding 20% ​​of the total amount is added to the primer and the topcoat respectively to adjust the viscosity to reach the ideal spraying requirement. Preferably, the diluent is ethylene glycol monomethyl ether (MOE), and the diluent and the primer or the diluent and the topcoat are stirred evenly and then left to stand for 5-10 minutes to eliminate bubbles. The mixed primer and topcoat can be applied after being filtered with a 100-mesh filter.

[0056] Preferably, in the step 3 of the present invention, two layers of primer and four layers of topcoat are sequentially applied on the bottom surface and cured, which specifically comprises the following steps:

[0057] Step 31: After the bottom surface is treated and cleaned, two coats of the primer in the titanium nano polymer coating are applied. The interval between the coatings of the primer is 4 hours to ensure the interlayer bonding strength.

[0058] Step 32: Wait for 4 hours for the primer to cure, and then apply four coats of the titanium nano polymer coating. The interval between each coat of topcoat is 4 hours, and the bottom surface to be applied needs to be rotated 180 degrees during this period to ensure uniform coating.

[0059] Step 33: After all coatings are applied, cure at room temperature for more than 7 days.

[0060] Preferably, the present invention uses an airless sprayer to coat the bottom surface. More preferably, before coating, a small amount of the mixed titanium nano-polymer coating can be weighed for trial coating and verification to ensure the single film thickness and quality.

[0061] Preferably, in the present invention, once the titanium nano polymer coating over-reacts and thickens during the spraying process, the coating should be stopped immediately, and the coating should be scrapped and re-mixed. The over-reaction time of the coating is related to the ambient temperature. When the temperature is high, the time required is short and the material should be less. On the contrary, when the temperature is low, the time required is long and the amount of material can be appropriately increased.

[0062] Preferably, in step 3, after each coat of primer or topcoat is applied, the appearance and thickness of the primer film or topcoat film are checked to ensure that there is no missing coating and that the thickness of each layer is uniform; if missing coating or insufficient thickness occurs, re-coat in time.

[0063] More preferably, the thickness of the primer layer is checked after the last primer film is completely dry and before curing. If the thickness is less than 80 μm, the number of coating layers needs to be increased until it is qualified. The thickness of the topcoat layer is checked after the last topcoat film is completely dry and before curing. If the thickness is less than 170 μm, the number of coating layers needs to be increased until it is qualified.

[0064] Preferably, in step 4, the appearance inspection is to visually inspect whether the surface of the titanium nano-coating is flat and smooth, and whether there are defects such as missing coating, stickiness, peeling, bubbles and scars.

[0065] The thickness inspection is specifically to use a thickness gauge to detect the thickness of the titanium nano coating. The thinnest point of the titanium nano coating should be ≥150μm. Preferably, when performing the thickness inspection, three areas to be inspected are selected on the surface of the titanium nano coating at the part to be inspected, and 10% of the area of ​​each area to be inspected is inspected. 2 For one inspection area, at least 2 points shall be randomly inspected in each inspection area, and the points shall be evenly distributed. The number of randomly inspected points at the weld shall not be less than 30% of the total number of inspection points.

[0066] If more than one point in each area to be inspected fails, the area is considered unqualified. If the unqualified area does not exceed 5%, the area where the titanium nano coating thickness is less than 90% of the specified thickness is re-coated; if the unqualified area exceeds 5%, the corresponding part is double-checked. If the unqualified area after double inspection still exceeds 5%, the titanium nano coating thickness of this part is unqualified and re-coating is performed until it passes; if the unqualified area after double inspection does not exceed 5%, the area where the titanium nano coating thickness is less than 90% of the specified thickness is re-coated.

[0067] The leakage inspection is as follows: Since titanium nano polymer coating is a static conductive coating, spark leak detector cannot be used. Use a 5-10 times magnifying glass for inspection. The one without leakage is qualified. The sampling rate of leakage inspection is equal to or greater than 5% of the coating area, and focus on weak links such as welds. If the number of leakage points is 1 / m 2 , repair, if the number of leaks exceeds 1 / m 2 , for comprehensive recoating.

[0068] The adhesion test is specifically as follows: using a knife blade to cut through the titanium nano-coating to form a V-shaped incision, and then peeling off the titanium nano-coating in the incision to test its adhesion.

[0069] Preferably, a sharp blade is used to vertically cut through the titanium nano-coating to form a o Use the tip of the knife to peel off the titanium nano coating in the incision from the intersection of the cutting line. If the titanium nano coating at the picked-up position is brittle point-like fracture, the titanium nano coating adhesion is qualified; if the titanium nano coating at the picked-up position is picked up or peeled off in pieces, the titanium nano coating adhesion is unqualified.

[0070] Preferably, when testing the adhesion, three test points are selected on the surface of the titanium nanocoating at the part to be inspected. If the test points are qualified, the adhesion of this part is qualified; if one of the test points is unqualified, the unqualified part is double-checked; if there is still one unqualified point after double checking, the adhesion of the titanium nanocoating of this part is unqualified.

[0071] The above content is an explanation of the preferred embodiments of the present invention, which can help those skilled in the art to more fully understand the technical solution of the present invention. However, these embodiments are merely illustrative, and it cannot be determined that the specific implementation methods of the present invention are limited to the description of these embodiments. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions and transformations can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A titanium nano-coated heat exchanger, comprising a main body and a heat exchange tube arranged inside the main body, wherein an air inlet and an air outlet are respectively arranged on both sides of the main body, and a water inlet and a water outlet are respectively arranged at both ends of the heat exchange tube, characterized in that: The inner wall of the main body and / or the inner wall of the air inlet and / or the inner wall of the air outlet and / or the inner wall and / or the outer wall of the heat exchange tube is the bottom surface, the surface of the bottom surface is smooth and free of attachments, and the surface roughness of the bottom surface is 40 to 70 μm; The bottom surface is provided with a titanium nano coating, the total thickness of the titanium nano coating is in the range of 270 μm to 300 μm, the titanium nano coating comprises a primer layer and a topcoat layer, the primer layer comprises at least two primer films, and the topcoat layer comprises at least four topcoat films; The components and proportions of the primer film include: epoxy resin: 43%, titanium nano-metal powder: 24%, acetone: 18%, curing agent: 5%, and mica powder: 10%; the components and proportions of the topcoat film include: polyurethane resin: 63%, titanium nano-metal powder: 15%, acetone: 12%, curing agent: 4%, and mica powder: 6%.

2. A coating method for a titanium nano-coated heat exchanger, applicable to the titanium nano-coated heat exchanger according to claim 1, characterized in that: The following steps are involved: Step 1: Clean, remove rust and roughen the bottom surface to make the surface roughness reach 40-70μm; Step 2: Mix epoxy resin, titanium nano metal powder, acetone, curing agent and mica powder in different proportions to form a primer and a topcoat of the titanium nano polymer coating, and add a diluent; Step 3: Apply two layers of primer and four layers of topcoat on the bottom surface in sequence and cure them to obtain a titanium nano-coated heat exchanger; Step 4: Perform appearance inspection, thickness inspection, leakage inspection and adhesion inspection on the titanium nano-coated heat exchanger.

3. The coating method of a titanium nano-coating heat exchanger according to claim 2, characterized in that: The step 1 specifically includes: Step 11: Use lye to wash the bottom surface with high pressure hot water to remove grease and dirt; Step 12: Use quartz sand as abrasive material, add it into the sandblasting machine, and sandblast the bottom surface; Step 13: After sandblasting, use a vacuum cleaner, dry and clean compressed air or a brush to remove dust from the bottom surface to ensure that there is no residue on the surface.

4. The coating method of a titanium nano-coating heat exchanger according to claim 3 is characterized in that: The particle sizes of the sand materials are the same or different, and the proportions of the sand materials with different particle sizes are roughly equal; the compressed air pressure in the sand blasting machine is controlled at 0.4-0.8Mpa.

5. The coating method of a titanium nano-coating heat exchanger according to claim 2, characterized in that: The step 2 of adding the diluent specifically comprises: preparing the primer and the topcoat in a correct ratio, and adding no more than 20% of the diluent to the primer and the topcoat respectively, stirring evenly and then standing for 5-10 minutes to eliminate bubbles, wherein the diluent is ethylene glycol methyl ether.

6. The coating method of a titanium nano-coating heat exchanger according to claim 2, characterized in that: The step 3 specifically includes the following steps: Step 31: After the bottom surface is treated and cleaned, two coats of the primer in the titanium nano polymer coating are applied, and the interval between the coatings of the primers is 4 hours to ensure the interlayer bonding strength; Step 32: After waiting for 4 hours and the primer is cured, four coats of the titanium nano polymer coating are applied, with each coat of topcoat applied at an interval of 4 hours, during which the bottom surface to be constructed is rotated 180 degrees to ensure uniform coating; Step 33: After all coatings are applied, cure at room temperature for more than 7 days.

7. A method for coating a titanium nano-coating heat exchanger according to claim 6, characterized in that: After each application of a primer or topcoat, check the appearance and thickness of the primer film or topcoat to ensure that there is no missing coating and that the thickness of each layer is uniform; if there is a missing coating or the thickness is insufficient, apply additional coating in time; after the last primer film is completely dry and before solidification, check the thickness of the primer layer. If the thickness is less than 80μm, increase the number of coating layers until it is qualified; after the last topcoat film is completely dry and before solidification, check the thickness of the topcoat layer. If the thickness is less than 170μm, increase the number of coating layers until it is qualified.

8. The coating method of a titanium nano-coating heat exchanger according to claim 2, characterized in that: Specifically, the appearance inspection includes visually inspecting whether the surface of the titanium nano-coating is flat and smooth, and whether there are defects such as missing coating, stickiness, peeling, bubbles and scars; The thickness inspection specifically includes using a thickness gauge to detect the thickness of the titanium nano coating, and the thinnest point of the titanium nano coating should be ≥150 μm; The leakage point inspection is specifically to use a 5-10 times magnifying glass to inspect, and the one without leakage points is qualified; The adhesion test is specifically to use a knife blade to cut through the titanium nano-coating to form a V-shaped incision, and then peel off the titanium nano-coating in the incision to test its adhesion.

9. The coating method of a titanium nano-coating heat exchanger according to claim 8, characterized in that: When conducting thickness inspection, three areas to be inspected are selected on the surface of the titanium nano-coating at the part to be inspected, and 10% of the area of ​​each area to be inspected is taken for inspection. 2 For one inspection area, at least 2 points shall be randomly inspected in each inspection area, and the points shall be evenly distributed. The number of randomly inspected points at the weld shall not be less than 30% of the total number of inspection points.

10. The coating method of a titanium nano-coating heat exchanger according to claim 8, characterized in that: The spot check rate of the leakage point inspection is equal to or greater than 5% of the coating area, and the weak links at the welds are inspected in particular; if the number of leakage points is 1 / m 2 , repair, if the number of leaks exceeds 1 / m 2 , for comprehensive recoating.

Images