Tubelet panel and method of and apparatus for manufacture thereof

DETAILED DESCRIPTION What is claimed is: 1.
Apparatus for producing a panel array of parallel tubes comprising; first means to engage the major faces of a plurality of strips, each having parallel longitudinal edges bordering opposed major faces and of stiff sheet material having a first melting temperature, and to support the strips with their major faces parallel and their first longitudinal edges parallel; means to engage and to support a first facing sheet against a first longitudinal edge of each strip in a region of said apparatus in which said means to engage strips engages the strips, the sheet being of a material having a second melting temperature above the first melting temperature of the strip material; means to apply heat and pressure to the face of the first facing sheet opposite the face adjacent the first edges of the strips at a temperature above the first melting temperature and below the second melting temperature in that region in which said first means to engage the strips is in engagement with the strips to melt the first longitudinal edges of the strips and displace the first sheet and the strips toward each other to bond the first edges to the first facing sheet without melting a preponderant portion of the major faces of the strips; second means to engage the major faces of the plurality of strips and to support the strips with their major faces parallel and their second longitudinal edges parallel; second means to engage and to support a second facing sheet against a second longitudinal edge of each strip in a region of said apparatus in which said second means to engage strips engages the strips, the sheet being of a material having a third melting temperature above the first melting temperature of the strip material; and means to apply heat and pressure to the face of the second facing sheet opposite the face adjacent the second longitudinal edge of the strips at a temperature above the first melting temperature and below the third melting temperature in the region in which said second means to engage the strips is in engagement with the strips to melt the second longitudinal edges of the strips and displace the second sheet and the strips toward each other to bond the second edges to the second facing sheet without melting a preponderant portion of the major faces of the strips