Non-cylindrical refrigerant conduit and method of making same

A heat exchanger assembly for transferring heat comprising;

• a first header having an interior surface and being generally cylindrical in cross-section to define a first cavity for collecting refrigerant vapor and extending along a first header axis between a pair of first header end portions;
• a second header defining a second cavity for receiving a refrigerant for liquid-to-vapor transformation and extending along a second header axis between a pair of second header end portions;
• said second header axis being parallel to said first header axis;
• each header including a lanced surface being flat and extending parallel to said corresponding header axis between said corresponding header end portions;
• each lanced surface including a plurality of truncated projections extending into said corresponding cavity and being axially spaced from one another between said corresponding header end portions to define valleys between adjacent truncated projections and defining a plurality of header slots extending transversely to said header axes;
• a plurality of refrigerant tubes each extending between a pair of refrigerant tube ends and extending in spaced and parallel relationship and transversely to said header axes between said headers;
• each of said refrigerant tubes having a generally rectangular cross-section and including at least one divider for supporting said refrigerant tube and defining a plurality of fluid passages extending between said refrigerant tube ends;
• each fluid passage being in fluid communication with said cavities for transferring refrigerant from said second cavity to said first cavity;
• said refrigerant tube ends of each refrigerant tube extending through one of said header slots of each header and into said corresponding 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;
• a plurality of fins disposed between adjacent refrigerant tubes and between each core reinforcement and the next adjacent of said refrigerant tubes for transferring heat from said refrigerant tubes;
• a refrigerant conduit having a conduit cross-section and disposed in said first cavity and extending along said first header axis;
• said conduit cross-section being generally semi-circular defining an arced surface and a chord surface interconnected with rounded ends;
• said refrigerant conduit including a plurality of orifices in fluid communication with said first cavity for transferring the refrigerant vapor from said first cavity to said refrigerant conduit to flow the refrigerant vapor along said refrigerant conduit;
• said first header including a plurality of support projections extending into said first cavity under said refrigerant conduit for positioning said refrigerant conduit;
• said support projections spaced from one another and aligned in two rows each parallel to said first header axis;
• a pair of first end caps each engaged and hermetically sealed to one of said first header end portions and to said refrigerant conduit;
• at least one of said first end caps defining a first aperture being in fluid communication with said refrigerant conduit for venting the refrigerant;
• a pair of second end caps each engaged and hermetically sealed to one of said second header end portions with at least one of said second end caps defining a second aperture in fluid communication with said second cavity for receiving the refrigerant;
• said arced surface of said conduit body portion engaged to said interior surface of said cylindrical first header and said chord surface of said conduit body portion being spaced from said refrigerant tube ends extending through said header slots and into said first cavity;
• said conduit end portion extending coaxially with said first header axis in one of said first header end portions to provide a central outlet for the refrigerant vapor;
• and
• said conduit body portion and said conduit transition portion extending along said first header axis between said first header end portions and said conduit end portion extending along said first header axis in one of said first header end portions;
• said refrigerant conduit defining a conduit body portion and at least one conduit end portion having a circular cross-section;
• said conduit body portion being offset from said conduit end portion in said first cavity;
• and
• a conduit transition portion interconnecting said conduit body portion and said conduit end portion.

A method for fabricating a heat exchanger assembly comprising the steps of;

• puncturing a generally cylindrical first header defining a first cavity and a generally cylindrical second header defining a second cavity in predetermined spaced intervals to define a plurality of header slots spaced along each header;
• producing a plurality of orifices in a generally cylindrical refrigerant conduit having a conduit cross-section and a conduit body portion and a conduit end portion;
• flattening a portion of the generally cylindrical refrigerant conduit to define the conduit cross-section as being generally semi-circular defining an arced surface and a chord surface;
• inserting the refrigerant conduit into the first cavity of the first header;
• engaging the arced surface of the conduit body portion of the refrigerant conduit with the first header;
• positioning the conduit end portion of the refrigerant conduit centrally in the first header;
• placing the first header and the second header in a stacker headering station fixture;
• pressing the headers onto a plurality of refrigerant tubes each defining a fluid passage for extending the refrigerant tubes through the header slots and into the cavities to fluidly communicate the fluid passages with the cavities;
• spacing the refrigerant tubes from the chord surface of the conduit body portion of the refrigerant conduit;
• and
• offsetting the conduit end portion of the refrigerant conduit from the conduit body portion of the refrigerant conduit before said inserting the refrigerant conduit into the first cavity step.

A method for fabricating a heat exchanger assembly comprising the steps of;

• oiling a pair of first header end portions of a generally cylindrical first header defining a first cavity and a pair of second header end portions of a generally cylindrical second header defining a second cavity;
• sealing one of a pair of first end caps about one of the first header end portions of the first header to seal the first cavity about one of the first header end portions;
• puncturing the first header and the second header in predetermined spaced intervals axially along each header to define a plurality of header slots spaced axially along each header;
• cutting a generally cylindrical tube to define a refrigerant conduit having a conduit cross-section and a conduit body portion and a conduit end portion;
• producing a plurality of orifices in the conduit body portion of the refrigerant conduit;
• flattening a portion of the generally cylindrical refrigerant conduit to define the conduit cross-section as being generally semi-circular defining an arced surface and a chord surface;
• inserting the refrigerant conduit into the first cavity of the first header;
• engaging the arced surface of the conduit body portion of the refrigerant conduit with the first header;
• positioning the conduit end portion of the refrigerant conduit centrally in the other of the first header end portions;
• producing a plurality of support projections spaced from one another and aligned in two rows on the first header and extending into the first cavity for contacting and supporting the conduit body portion of the refrigerant conduit;
• fluidly communicating the conduit end portion of the refrigerant conduit with a first aperture defined by the other of the pair of first end caps;
• sealing the other of the pair of first end caps about the other of the first header end portions and about the conduit end portion of the refrigerant conduit to seal the first cavity about the other of the first header end portions;
• sealing a pair of second end caps with at least one of the end caps defining a second aperture about the second header end portions of the second header to seal the second cavity about the second header end portions;
• placing the first header and the second header in a stacker headering station fixture;
• interleaving fins between a plurality of refrigerant tubes each defining a fluid passage to define a fin matrix;
• disposing a pair of core reinforcements outwards of the fin matrix to define a core assembly;
• transferring the core assembly to the stacker headering station;
• pressing the headers onto the fin matrix for extending the refrigerant tubes through the header slots and into the cavities to fluidly communicate the fluid passages with the cavities;
• spacing the refrigerant tubes from the chord surface of the conduit body portion of the refrigerant conduit;
• furnace brazing the headers and core assembly;
• leak testing the heat exchanger assembly;
• and
• offsetting the conduit end portion of the refrigerant conduit from the conduit body portion of the refrigerant conduit before said inserting the refrigerant conduit into the first cavity step.