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Aluminium-pipe heat exchanger and surface treatment method

A technology of heat exchanger and aluminum tube, which is applied in the field of aluminum tube heat exchanger and its surface treatment, which can solve the problems of increasing the thermal resistance of tube-fin expansion joints, low compressive strength, and harmful environment, so as to improve corrosion resistance Performance, extended service life, and improved corrosion resistance

Inactive Publication Date: 2014-06-25
MIDEA GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Zinc spraying, galvanizing, and coating treatment are very effective for aluminum condensing heat exchangers at medium and low temperatures, low humidity, and non-corrosive gases, but in harsh environments such as high temperature, high humidity, and corrosive gases, due to Using the surface of the aluminum tube as a sacrificial anode will lead to a rapid reduction in the wall thickness of the aluminum tube, which will greatly reduce the safety of the aluminum alloy heat exchanger as a heat exchanger system on the condensing side for the aluminum alloy heat exchanger with low compressive strength
The rapid corrosion of the zinc spray layer on the surface will also greatly increase the thermal resistance of the tube-fin expansion joint and accelerate the attenuation of the heat transfer performance of the aluminum heat exchanger
In addition, zinc spraying and surface passivation by complex salts or electrophoretic painting treatment will cause a significant increase in cost, toxic Cr ion residues or residual liquid will pollute water or emit volatile VOCs, which are obviously harmful to the environment. Impact

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0069] The heat transfer tube 1 is a straight-toothed tube, and the fin 2 is a common bridge piece made of aluminum alloy 3003. Amorphous Ni-P chemical composite coating with molybdate as additive is plated under normal pressure and temperature of 88 degrees Celsius. The composition and content of the plating solution are:

[0070] Nickel sulfate: 43g / L;

[0071] Sodium dihydrogen phosphate: 25g / L

[0072] Sodium citrate: 40g / L

[0073] Ammonium acetate: 35g / L

[0074] Ammonium fluoride: 1g / L

[0075] Sodium molybdate: 1mg / L

[0076] The pH of the plating solution is controlled at 8, the temperature of the annealing dehydrogenation treatment and recrystallization annealing treatment of the surface coating is controlled at 490 degrees Celsius, and the thickness of the coating is 30 microns.

[0077] After the electroless plating is completed, connect the fins 2 to the heat transfer tube 1, and then dip-coat the part of the heat transfer tube that is not covered by the fins...

Embodiment 2

[0079] The heat transfer tube 1 is an ordinary round tube, and the fin 2 is a louver slit, with 3003 aluminum tube as the base material. At normal pressure and a temperature of 80 degrees Celsius, an amorphous nickel-phosphorus chemical composite coating with molybdate as an additive is plated. The composition and content of the plating solution are:

[0080] Nickel sulfate: 57g / L

[0081] Sodium dihydrogen phosphate: 20g / L

[0082] Sodium citrate: 45g / L

[0083] Ammonium acetate: 30g / L

[0084] Ammonium fluoride: 1g / L

[0085] Sodium molybdate: 1mg / L;

[0086] The pH of the plating solution is controlled at 7, and the temperature of the surface coating annealing dehydrogenation treatment and recrystallization annealing treatment is controlled at 505 degrees Celsius; the thickness of the coating film is 30 microns,

[0087] After the electroless plating is completed, connect the fins 2 to the heat transfer tube 1, and then dip-coat the part of the heat transfer tube that ...

Embodiment 3

[0089] The heat transfer tube 1 is an internally threaded tube, the fin 2 is a corrugated sheet, and the aluminum alloy 3003 is used as the base material. At normal pressure, the temperature is 90 degrees Celsius, and the nickel-phosphorus chemical composite coating is plated with molybdate as a stabilizer. The combination of the plating solution The points and content are:

[0090] Nickel sulfate: 40g / L

[0091] Sodium dihydrogen phosphate: 30g / L

[0092] Sodium citrate: 35g / L

[0093] Ammonium acetate: 40g / L

[0094] Ammonium fluoride: 2g / L

[0095] Sodium molybdate: 5mg / L

[0096] The pH value of the plating solution is controlled to be 9, the annealing temperature is 510 degrees Celsius, and the thickness of the coating film is 20 microns.

[0097] After the electroless plating is completed, connect the fin 2 to the heat transfer tube 1, and then brush the inorganic zinc paint on the part of the heat transfer tube that is not covered by fins. The main component of the...

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Abstract

The invention discloses an aluminium-pipe heat exchanger. The aluminium-pipe heat exchanger comprises an aluminium heat transferring pipe and aluminium fins partially coating the heat transferring pipe. The aluminium-pipe heat exchanger is characterized in that the outer surface of the heat transferring pipe is plated with amorphous Ni-P chemical composite plating layer; the exposed part of the heat transferring pipe, which is not coated by the aluminium fins, is coated with a corrosion inhibitor coating or an anti-corrosion coating. The invention also provides a method for preparing the aluminium-pipe heat exchanger and heat exchange equipment with the aluminium-pipe heat exchanger. The aluminium-pipe heat exchanger and the surface treatment method have the advantages that the corrosion resistance of the heat transferring pipe can be improved and the service life can be prolonged.

Description

technical field [0001] The invention relates to the technical field of aluminum tube heat exchangers, in particular to an aluminum tube heat exchanger and a surface treatment method thereof. Background technique [0002] As we all know, aluminum has good thermal conductivity and ductility, excellent extrusion and tensile properties, and it is easy to prepare round tubes, internal threaded tubes, straight-toothed tubes, oval tubes, etc. with high internal and external ribbing coefficients, making the equipment compact and lightweight Light, small size; and compared to copper alloys, the cost is low and the price fluctuation is small, so it is widely used in heat exchangers for refrigeration. [0003] The aluminum tube heat exchanger of the outdoor unit or condenser has been in the outdoor environment for a long time. Due to the diversity and harshness of the outdoor environment, the requirements for its surface corrosion resistance are relatively high. such as high temperatu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C18/32F25B39/04F28F21/08F28F19/06
Inventor 黄凤勇
Owner MIDEA GRP CO LTD