Cooling channel structure and burner

A cooling channel structure, comprising:

• a tubular member with openings at both ends;
• and
• cooling channels for a cooling medium for cooling the tubular member, the cooling channels including:
• spiral outer surface-side channels on an outer surface side of the tubular member;
• spiral inner surface-side channels on an inner surface side of the tubular member in an inner portion of the tubular member or on a surface of the tubular member;
• and
• folded channels, respectively, connecting the spiral outer surface-side channels and the spiral inner surface-side channels on one end side of the tubular member,
• wherein the folded channels are curved such that a first direction in which the spiral outer surface-side channels curve toward a downstream side along a spiral and a second direction in which the spiral inner surface-side channels curve toward the downstream side along the spiral are the same as each other.

A cooling channel structure, comprising:

• a tubular member with openings at both ends;
• a header;
• and
• cooling channels for a cooling medium for cooling the tubular member, the cooling channels including:
• spiral outer surface-side channels on an outer surface side of the tubular member;
• spiral inner surface-side channels on an inner surface side of the tubular member in an inner portion of the tubular member or on a surface of the tubular member;
• and
• folded channels, respectively, connecting the spiral outer surface-side channels and the spiral inner surface-side channels on a first end side of the tubular member,
• wherein the header connects end portions of the spiral inner surface-side channels, on a second end side of the tubular member.