Heat Exchanger Tube, Heat Exchanger, and Manufacturing Method Thereof

Abstract

This invention relates to a method of manufacturing an aluminum heat exchanger tube. In forming a thermally sprayed layer 21 on a surface of an aluminum flat tube by thermally spraying Al—Si alloy thermal-spraying particles, quenching the thermally sprayed thermal-spraying particles in a molten state to make them adhere to the tube core 2 a . The surface of the thermally sprayed layer 21 is smoothed with, e.g., reduction rolls to form a brazing layer 20 . With this method, brazing defects due to fin detachment, erosion to the tube of the brazing material, etc., can be prevented, resulting in good brazing performance.

1 . A method of manufacturing an aluminum heat exchanger tube, the method comprising the steps of:
 in forming a thermally sprayed layer on a surface of an aluminum flat tube by thermally spraying Al—Si alloy thermal-spraying particles, quenching the thermally sprayed thermal-spraying particles in a molten state to make them adhere to a tube core; and   smoothing a surface of the thermally sprayed layer to form a brazing layer.   
   
   
       2 . The method of manufacturing an aluminum heat exchanger tube as recited in  claim 1 , wherein surface roughness (Ry) of the tube core is adjusted to less than 10 μm. 
   
   
       3 . The method of manufacturing an aluminum heat exchanger tube as recited in  claim 1  or  2 , wherein surface roughness (Ry) of the brazing layer is adjusted to less than 50 μm. 
   
   
       4 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  3 , wherein a thermal-spraying temperature of the thermal-spraying particles is adjusted to 3,000° C. or above. 
   
   
       5 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  4 , wherein the thermal-spraying particles are cooled to 800° C. or below after reaching the tube core. 
   
   
       6 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  5 , wherein in thermally spraying the thermal-spraying particles, a temperature difference between the thermal-spraying particles in a molten state and the thermal-spraying particles reached the tube core in a cooled state is adjusted to 2500° C. or more. 
   
   
       7 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  6 , wherein in thermally spraying the thermal-spraying particles, the thermal-spraying particles reached the tube core are cooled by releasing the heat to the tube core. 
   
   
       8 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  7 , wherein an average equivalent diameter of Si crystallization particles in the thermally sprayed layer is adjusted to 1 μm or less. 
   
   
       9 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  8 , wherein an apparent volume rate (filling rate) of the brazing material in the brazing layer is adjusted to 40% or more. 
   
   
       10 . The method of manufacturing an aluminum heart exchanger tube as recited in any one of  claims 1  to  9 , wherein in thermally spraying the thermal-spraying particles, a thermal-spraying distance from a spraying position of the thermal-spraying particles to an adhering position on the tube core is adjusted to 30 to 150 mm. 
   
   
       11 . The method of manufacturing an aluminum heart exchanger tube as recited in any one of  claims 1  to  10 , wherein thermal spraying of the thermal-spraying particles is performed by an arc spraying method. 
   
   
       12 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  11 , wherein a Si content in the thermally sprayed layer is adjusted to 6 to 15 mass %. 
   
   
       13 . The method of manufacturing an aluminum heart exchanger tube as recited in any one of  claims 1  to  12 , wherein an average thickness of the brazing layer is adjusted to 3 to 50 μm. 
   
   
       14 . The method of manufacturing an aluminum heart exchanger tube as recited in any one of  claims 1  to  13 , wherein the surface of the thermally sprayed layer is pressed with reduction rolls to smooth the surface. 
   
   
       15 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  14 , wherein Zn is contained to the thermally sprayed layer. 
   
   
       16 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  15 , wherein Zn and Cu are contained to the thermally sprayed layer. 
   
   
       17 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  16 , wherein the tube core is formed by extrusion, and the thermal-spraying particles are thermally sprayed to the tube core immediately after the extrusion. 
   
   
       18 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  17 , wherein each thermal-spraying particle adheres to the surface of the tube core in a flat state. 
   
   
       19 . The method of manufacturing an aluminum heat exchanger tube as recited in any one of  claims 1  to  18 , wherein the thermal-spraying particles are thermally sprayed under a non-oxidizing atmosphere. 
   
   
       20 . A method of manufacturing an aluminum heat exchanger tube, the method comprising the steps of:
 in forming a thermally sprayed layer on a surface of an aluminum flat tube by thermally spraying Al—Si alloy thermal-spraying particles, thermally spraying the thermal-spraying particles to a tube core by an arc spraying method, and quenching the thermally sprayed thermal-spraying particles to 800° C. or below; and   smoothing a surface of the thermally sprayed layer to form a brazing layer.   
   
   
       21 . A method of manufacturing an aluminum heat exchanger tube, the method comprising the steps of:
 in forming a thermally sprayed layer on a surf ace of an aluminum flat tube by thermally spraying Al—Si alloy thermal-spraying particles, performing the thermal spraying by arc spraying in which a thermal-spraying distance from a spraying position of the thermal-spraying particles to an adhering position of the tube core is adjusted to 30 to 150 mm; and   smoothing a surface of the thermally sprayed layer to form a brazing layer.   
   
   
       22 . A method of manufacturing an aluminum ha at exchanger tube, the method comprising the steps of:
 in forming a thermally sprayed layer on a surface of an aluminum flat tube by thermally spraying Al—Si alloy thermal-spraying particles, thermally spraying the thermal-spraying particles with a thermal-spraying temperature of 3,000° C. or above and cooling them to 800° C. or below to make them adhere to a tube core; and   smoothing a surface of the thermally sprayed layer to form a brazing layer.   
   
   
       23 . A method of manufacturing an aluminum heat exchanger tube, the method comprising the steps of:
 in forming a thermally sprayed layer on a surf ace of an aluminum flat tube by thermally spraying Al—Si alloy thermal-spraying particles, thermally spraying the thermal-spraying particles in a molten state and cooling to make them adhere to a tube core, and adjusting a temperature difference between the thermal-spraying particles in a molten state and the thermal-spraying particles after the cooling is adjusted to 2,500° C. or more; and   smoothing a surface of the thermally sprayed layer to form a brazing layer.   
   
   
       24 . An aluminum heat exchanger tube manufactured by the method as recited in any one of the  claims 1  to  23 . 
   
   
       25 . An aluminum heat exchanger tube, comprising:
 an aluminum flat tube core; and   a thermally sprayed layer formed on a surface of the tube core by thermally spraying thermal-spraying particles of molten Al—Si alloy,   wherein a surface of the thermally sprayed layer is smoothed to form a brazing layer, and   wherein an average equivalent diameter of Si crystallization particles in the thermally sprayed layer is adjusted to 1 μm or less.   
   
   
       26 . The aluminum heat exchanger tube as recited in  claim 25 , wherein an apparent volume rate (filling rate) of the brazing material in the brazing layer is adjusted to 40% or more. 
   
   
       27 . An aluminum heat exchanger including aluminum heat exchanger tubes and aluminum fins brazed to the tubes in an assembled state, wherein the heat exchanger tubes are manufactured by the method as recited in any one of  claims 1  to  23 . 
   
   
       28 . An aluminum heat exchanger including a pair of aluminum headers and a plurality of heat exchanger tubes arranged in a longitudinal direction of the header with a fin interposed therebetween, end portions of the heat exchanger tubes being communicated with the headers,
 wherein the heat exchanger tubes are manufactured by the method as recited in any one of  claims 1  to  23 .   
   
   
       29 . A method of manufacturing an aluminum heat exchanger, the method comprising:
 a step of preparing an aluminum heat exchanger tube manufactured by the method as recited in any one of  claims 1  to  23 ;   a step of preparing an aluminum fin; and   a step of brazing the heat exchanger tube and the fin in an assembled state.   
   
   
       30 . A method of manufacturing an aluminum heat exchanger, the method comprising:
 a step of preparing a plurality of aluminum heat exchanger tubes manufactured by the method as recited in any one of  claims 1  to  23 ;   a step of preparing a plurality of aluminum fins;   a step of preparing a pair of headers;   a step of obtaining a provisional assembly in which the plurality of heat exchanger tubes arranged in a longitudinal direction of the header with the fin interposed therebetween are assembled with the headers with end portions of each heat exchanging tube communicated with the headers;   a step of integrally brazing adjacent heat exchanger tubes and the fins by simultaneously brazing the provisional assembly.   
   
   
       31 . A refrigeration cycle in which refrigerant compressed by a compressor is condensed with a condensed, and the condensed refrigerant is decompressed by passing through a decompressor, and the decompressed refrigerant is evaporated with an evaporator and returned to the compressor,
 wherein the condenser is constituted by the aluminum heat exchanger as recited in  claim 28 .