Sleeved flexible metal piping, method of manufacturing same and flue system application of same

A sleeved gas conduit system which includes:

• (a) an upstream section of sleeved flexible metal piping having an inlet and outlet ends;
• (b) a downstream section of sleeved flexible metal piping having an inlet and outlet ends;
• (c) each said sleeved flexible metal piping section including:
• (1) a first, inner spiral winding comprising a metallic band with leading and trailing edges;
• (2) a second, outer spiral winding comprising a metallic band with leading and trailing edges, said outer winding overlying said inner winding, aid outer spiral winding having an outer diameter;
• (3) said leading edge of said inner winding being interlocked with said trailing edge of said inner winding;
• (4) a spiral seam including means for connecting said outer winding leading and trailing edges with said inner winding interlocked leading and trailing edges respectively;
• (5) a tubular sleeve receiving said interlocked inner and outer spiral windings, said tubular sleeve having an inner diameter substantially equal to said outer spiral winding outer diameter, said tubular sleeve being in substantially continuous contact with said outer spiral winding;
• and
• (d) connector means for fluidically connecting said upstream section outlet end and said downstream section inlet end.

A method of forming insulated flexible metal piping, which comprises the steps of:

• (a) providing a first, inner spiral winding comprising a metallic band with leading and trailing edges;
• (b) providing a second, outer spiral winding comprising a metallic band with leading and trailing edges and winding said outer winding in overlying relationship with respect to said inner winding, and providing said outer winding with an outer diameter;
• (c) interlocking said inner winding leading edge with said inner winding trailing edge;
• (d) forming a spiral seam including means for connecting said outer winding leading and trailing edges with said inner winding interlocked leading and trailing edges respectively;
• and
• (e) providing a tubular sleeve and slidably, longitudinally inserting said inner and outer windings in said tubular sleeve, providing said tubular sleeve with an inner diameter substantially equal to the outer winding outer diameter, and contacting said outer winding substantially continuously with said sleeve.

Sleeved flexible metal piping, which includes:

• (a) a first, inner spiral winding comprising a metallic band with leading and trailing edges;
• (b) a second, outer spiral winding comprising a metallic band with leading and trailing edges, said outer winding overlying said inner winding;
• (c) said leading edge of said inner winding being interlocked with said trailing edge of said inner winding;
• (d) a spiral seam including means for connecting said outer winding leading and trailing edges with said inner winding interlocked leading and trailing edges;
• (e) a tubular sleeve receiving said interlocked inner and outer spiral windings;
• and
• (f) said spiral seam being knurled.

Sleeved flexible metal piping, which includes:

• (a) a first, inner spiral winding comprising a metallic band with leading and trailing edges;
• (b) a second, outer spiral winding comprising a metallic band with leading and trailing edges, said outer winding overlying said inner winding;
• (c) said leading edge of said inner winding being interlocked with said trailing edge of said inner winding;
• (d) a spiral seam including means for connecting said outer winding leading and trailing edges with said inner winding interlocked leading and trailing edges;
• (e) a tubular sleeve receiving said interlocked inner and outer spiral windings;
• and
• (f) an intermediate spiral winding comprising an insulating material spiral-wound between said inner and outer spiral windings.

Sleeved flexible metal piping, which includes:

• (a) a first, inner spiral winding comprising a metallic band with leading and trailing edges;
• (b) a second, outer spiral winding comprising a metallic band with leading and trailing edges, said outer winding overlying said inner winding;
• (c) said leading edge of said inner winding being interlocked with said trailing edge of said inner winding;
• (d) a spiral seam including means for connecting said outer winding leading and trailing edges with said inner winding interlocked leading and trailing edges;
• (e) a tubular sleeve receiving said interlocked inner and outer spiral windings;
• (f) said outer winding leading and trailing edges overlie each other;
• and
• (g) said interlocked spiral seam being knurled.