Apparatus and process for making tube in sheet heat exchangers

An apparatus for forming an opening in a composite metal panel comprising at least two sheets of metal having a bond therebetween which can be broken by inflation, said opening extending between said sheets of metal and inwardly of said panel from an edge thereof, said composite metal panel being adapted for forming a heat exchanger therefrom having a desired pattern of inflated tubular passageways therein, said apparatus comprising:

• means for hammering said edge of said panel at a position wherein said opening is to be formed for delineating a bond interface between said sheets of said panel, said hammering means including a hammering member and means for moving said hammering member to and fro against said edge while simultaneously rocking said member about said edge, said hammering member comprising a cylindrical member defining a cylindrical hammer surface which is adapted to engage said edge of said panel, said cylindrical member defining a cylinder axis, said means for simultaneously rocking said member being adapted to cause said cylinder axis to rock about a plane of said panel;
• and
• means adapted to be positioned at said delineated bond interface at said edge of said panel for forming said opening;
• whereby improved delineation of said bond interface is provided.

In a process for forming an opening in a composite metal panel comprising at least two sheets of metal having a bond therebetween, which can be broken by inflation, said opening extending between said sheets of metal and inwardly of said panel from an edge thereof, said composite panel being adapted for forming a heat exchanger therefrom having a desired pattern of inflated tubular passageways therein, said process comprising:

• hammering with a blunt surface said edge of said panel at a position wherein said opening is to be formed for delineating a bond interface between said sheets of said panel;
• the improvement wherein;
• said hammering step comprises the steps of providing a hammering member and moving said hammering member to and fro against said edge while simultaneously rocking said member about said edge and a plane of said panel, said hammering step being adapted to upset the metal of said panel at said position at said edge to form widely spaced lips on said sheets to delineate said bond interface;
• whereby improved delineation of said bond interface is provided.

A process for forming an opening in a composite metal panel comprising at least two sheets of metal having a bond therebetween, which can be broken by inflation, said opening extending between said sheets of metal and inwardly of said panel from an edge thereof, said composite panel being adapted for forming a heat exchanger therefrom having a desired pattern of inflated tubular passageways therein, said process comprising:

• hammering said edge of said panel at a position wherein said opening is to be formed for delineating a bond interface between said sheets of said panel, said hammering step including the steps of providing a hammering member and moving said hammering member to and fro against said edge while simultaneously rocking said member about said edge, said step of providing said hammering member comprising providing a cylindrical member defining a cylindrical hammer surface which is adapted to engage an edge of said panel, said cylindrical member also defining a cylinder axis, and wherein said step of simultaneously rocking said member causes said cylinder axis to rock about a plane of said panel;
• and
• positioning at said delineated bond interface at said edge of said panel, a means for forming said opening;
• whereby improved delineation of said bond interface is provided.