Distributor tube and end cap subassembly

A heat exchanger assembly for dissipating heat comprising:

• a first header having an interior surface and being generally circular in cross-section to define a first cavity for collecting a refrigerant vapor and extending along a first header axis between a pair of first header ends;
• a second header having an interior surface and being generally circular in cross-section to define a second cavity for receiving a refrigerant liquid and extending along a second header axis between a pair of second header ends;
• said second header axis being parallel to said first header axis;
• said headers each including a lanced surface being flat and extending parallel to said header axes between said corresponding header ends;
• each of said lanced surfaces including a plurality of truncated projections disposed in predetermined spaced intervals axially along said headers and extending into said corresponding cavities to define a plurality of header slots;
• said header slots of said first header facing toward said header slots of said second header;
• a first refrigerant conduit disposed in said first cavity and extending generally parallel to said first header axis between said first conduit ends for transferring said refrigerant vapor therethrough;
• said first refrigerant conduit including a plurality of orifices in fluid communication with said first cavity for transferring said refrigerant vapor from said first cavity to said first refrigerant conduit;
• a second refrigerant conduit disposed in said second cavity and extending generally parallel to said second header axis between said second conduit ends for transferring said refrigerant therethrough;
• said second refrigerant conduit including a plurality of orifices in fluid communication with said second cavity for transferring said refrigerant from said second refrigerant conduit to said second cavity;
• said refrigerant conduits each including a conduit body portion and a conduit outlet portion interconnected by a conduit transition portion with said conduit body portions being offset from said conduit outlet portions in said corresponding cavities for spacing said conduit body portions from said refrigerant tubes and for positioning said conduit outlet portions centrally in said corresponding cavities;
• said refrigerant conduits each having a generally uniform cross-section throughout said conduit portions;
• said conduit ends opposite said corresponding conduit outlet portions being sealed for closing one of said conduit ends of each of said refrigerant conduits;
• said refrigerant conduits comprising an aluminum material;
• said headers including a plurality of indentations extending into said corresponding cavities to contact said corresponding conduit body portions disposed in said cavities for positioning said refrigerant conduits against said interior surface of said corresponding headers;
• said indentations being spaced from one another and axially aligned in two rows parallel to said header axes;
• an open end cap engaging said interior surface of each of said headers at a predetermined axial position between said truncated projections and one of said corresponding header ends and a closed end cap engaging said interior surface of each of said headers at a predetermined axial position between said truncated projections and the opposite one of said header ends;
• said open end cap engaging said first header being adjacent the opposite one of said header ends from said open end cap engaging said second header;
• said open end caps each defining an aperture encompassing and engaging said corresponding conduit outlet portions adjacent said conduit transition portions so that said refrigerant conduits extend through said apertures and outward of said header ends for conveying said refrigerant;
• said closed end caps comprising a continuous sheet of metal;
• said open end caps comprising a clad two-sided material;
• a plurality of refrigerant tubes extending between refrigerant tube ends in spaced and parallel relationship to one another and transversely to said header axes between said headers;
• each of said refrigerant tube ends extending through one of said header slots of said corresponding headers and into said corresponding cavities;
• each of said refrigerant tubes having a generally rectangular cross-section and including at least one divider defining a plurality of fluid passages extending between said refrigerant tube ends and being in fluid communication with said cavities for transferring said refrigerant vapor from said second cavity to said first cavity;
• a pair of core reinforcements disposed outwards of said refrigerant tubes and extending between said headers in a parallel and spaced relationship to said refrigerant tubes for protecting said refrigerant tubes and defining a core structure;
• a plurality of cooling fins interleaved between adjacent refrigerant tubes and between said core reinforcements and said adjacent refrigerant tubes for transferring heat away from said refrigerant tubes;
• each of said refrigerant conduits including an inner radial abutment disposed about the circumference of said conduit outlet portions adjacent said conduit transition portions of said refrigerant conduits and abutting said corresponding open end caps;
• each of said refrigerant conduits including an outer radial abutment disposed about the circumference of said conduit outlet portions and spaced from said inner radial abutments by said open end caps and abutting said open end caps for retaining said open end caps in axial position for brazing said refrigerant conduits to said open end caps;
• each of said headers including a notch extending a predetermined distance axially from each of said header ends to a notch bottom.

A method for fabricating a heat exchanger assembly of the type including a plurality of refrigerant tubes extending between an inlet header and outlet header and a refrigerant conduit disposed in at least one of the headers for uniformly distributing a refrigerant comprising the steps of:

• inserting a first refrigerant conduit through an open end cap;
• inserting the first refrigerant conduit and the open end cap into a first header;
• disposing a second header in spaced and parallel relationship to the first header;
• inserting a plurality of refrigerant tubes each defining at least one fluid passage into the first header and into the second header so that refrigerant tubes extend between the first header and the second header;
• and
• forming an inner radial abutment for abutting the open end cap upon engaging the first refrigerant conduit to the open end cap and forming an outer radial abutment spaced from the inner radial abutment by the open end cap for retaining the open end cap in position between the abutments for inserting the first refrigerant conduit and the open end cap as a subassembly into the first header.

A method for fabricating a heat exchanger assembly of the type including a plurality of refrigerant tubes extending between an inlet header and outlet header and a refrigerant conduit disposed in at least one of the headers for uniformly distributing a refrigerant comprising the steps of:

• cutting a first generally cylindrical tube comprising an aluminum material and having a generally uniform cross-section to define a first header extending along a first header axis between a pair of first header ends and having an interior surface defining a first cavity;
• cutting a second generally cylindrical tube comprising a an aluminum material and having a generally uniform cross-section to define a second header extending along a second header axis between a pair of second header ends and having an interior surface defining a second cavity;
• puncturing a plurality of header slots radially into and at predetermined spaced intervals axially along each of the headers;
• cutting a first generally cylindrical tube comprising an aluminum material and having a generally uniform cross-section to define a first refrigerant conduit extending between a pair of first conduit ends;
• cutting a second generally cylindrical tube comprising an aluminum material and having a generally uniform cross-section to define a second refrigerant conduit extending between a pair of second conduit ends;
• puncturing a plurality of orifices in a conduit body portion in each of the refrigerant conduits;
• offsetting each of the refrigerant conduits adjacent to the conduit body portion thereof to define a conduit transition portion and a conduit outlet portion;
• sealing each of the conduit ends opposite the corresponding conduit outlet portions of each of the refrigerant conduits to close the corresponding conduit ends;
• inserting each of the conduit outlet portions through an aperture of an open end cap so that the open end caps engages the conduit outlet portions adjacent the conduit transition portions;
• inserting each of the refrigerant conduits and the corresponding open end caps into the corresponding headers so that the corresponding conduit body portion opposite the orifices engages the interior surface of the corresponding headers so that the orifices of the refrigerant conduits are disposed in a predetermined relation relative to the header slots and the open end caps are pressed into engagement with the interior surface of the headers;
• forming a plurality of indentations spaced from one another and axially aligned in two rows in each of the headers and extending into the corresponding cavities to contact the corresponding conduit body portion for positioning each of the refrigerant conduits against the interior surface of the adjacent one of the headers;
• inserting a closed end cap into each of the header ends opposite the corresponding open end cap and adjacent to the corresponding conduit ends in each of the headers so that the closed end caps are pressed into engagement with the corresponding interior surface of the headers;
• placing the first header and the second header in a stacker headering station fixture so that the open end cap engaging the first header end is disposed opposite from the open end cap engaging the second header end;
• disposing a plurality of refrigerant tubes each including at least one fluid passage extending between refrigerant tube ends in spaced and parallel relationship with one another;
• disposing a pair of core reinforcements outwards of the refrigerant tubes and cooling fins to define a core structure;
• interleaving cooling fins between adjacent refrigerant tubes and between said core reinforcements and said adjacent refrigerant tubes for transferring heat away from said refrigerant tubes;
• transferring the core structure to the stacker headering station;
• inserting the refrigerant tubes into of each of the headers by pressing the refrigerant tube ends into the header slots so that the fluid passages of the refrigerant tubes are in fluid communication with the corresponding header cavities and the refrigerant tubes are spaced from the corresponding refrigerant conduits in the cavities;
• furnace brazing the headers and the end caps and the refrigerant conduits and the core structure;
• leak testing the end caps about the header ends;
• forming an inner radial abutment about the circumference of the conduit outlet portions of each of the refrigerant conduits adjacent to the corresponding conduit transition portions for abutting the open end caps upon inserting the conduit outlet portions through the apertures of the open end caps;
• forming an outer radial abutment about the circumference of the conduit outlet portions of each of the refrigerant conduits and spaced from the inner radial abutments by the open end caps for abutting the open end caps and retaining the open end caps in position for inserting the refrigerant conduits and the open end caps into the corresponding headers;
• cutting a notch extending axially into each of the header ends to a notch bottom disposed a predetermined distance axially into in the headers;
• and
• wherein said pressing the end caps into the headers is further defined by engaging each of the end caps with a tool to push the end caps into the headers until the tool engages the notch bottom.