Brazing a heat exchanger with a moving brazing tool
A method and apparatus for manufacturing a brazed heat exchanger. The method includes the steps of: assembling the heat exchanger components to form at least one unbrazed heat exchanger core in a core builder machine; without removing the at least one heat exchanger core from the core builder machine, enclosing the heat exchanger core with a brazing tool arrangement adapted to form a chamber, optionally, evacuating the chamber and/or filling the chamber with a controlled atmosphere; brazing the heat exchanger core in the chamber to form a brazed heat exchanger.
1. A method of manufacturing at least one brazed heat exchanger, comprising the steps of:
a. providing components for a heat exchanger and providing a core builder machine comprising a table and a brazing tool arrangement;
b. assembling the heat exchanger components to form at least one unbrazed heat exchanger core on the table of the core builder machine;
c. moving the brazing tool arrangement relative to the table such that the brazing tool arrangement forms a chamber on the table that at least partially encloses the at least one heat exchanger core on the table of the core builder machine, the brazing tool arrangement comprising means to heat the interior of the chamber, wherein moving the brazing tool arrangement comprises advancing opposing headers or opposing side plates towards the at least one heat exchanger core on the table and lowering a top plate towards the table such that the headers or side plates and the top plate together form the chamber on the table;
d. optionally, at least partially evacuating the chamber and/or at least partially filling the chamber with an inert and/or a reactive gas;
e. brazing the at least one heat exchanger core in the chamber to form the at least one brazed heat exchanger on the table of the core builder machine.
2. The method according to claim 1 , wherein the brazing step includes heating the at least one heat exchanger core in the chamber by inductive, radiation and/or conductive heating, optionally to a temperature in a range of about 530° C. to about 615° C., for a period long enough for melting, wetting and spreading of a filler metal or brazing material joining the components for the heat exchanger.
3. The method according to claim 1 , wherein the heat exchanger components are lubricated with an evaporative lubricant prior to being assembled, and wherein the at least partial vacuum is created in the chamber prior to the brazing step, until a sufficient portion of the evaporative lubricant has evaporated.
4. The method according to claim 1 , wherein the at least one heat exchanger core is not fluxed prior to brazing.
5. The method according to claim 1 , wherein at least some of the heat exchanger components are manufactured from aluminium alloy brazing sheet including a core layer clad on one or both sides with a filler alloy, and wherein the core alloy is selected from an alloy belonging to the AA1xxx, AA3xxx, AA5xxx, AA6xxx, AA7xxx or AA8xxx series, and the filler alloy belongs to the AA4xxx series.
6. The method according to claim 1 , wherein the brazing is carried out at temperatures between 570° C. and 610° C.
7. The method according to claim 1 , wherein the cycle time for the manufacturing the at least one brazed heat exchanger is between 1 and 45 minutes.
8. The method according to claim 1 , comprising a step of cooling of the at least one brazed heat exchanger after brazing.
9. The method according to claim 1 , wherein the cycle time for the manufacturing the at least one brazed heat exchanger is between 5 and 25 minutes.
10. The method according to claim 1 , wherein the components for the heat exchanger are selected from members of the group consisting of tubes, fins, headers, side supports/members, brackets and mounting components.