Surface current heating apparatus having spaced-apart hollow heat generating members with conductor extending therethrough

A surface current heating apparatus, comprising:

• a plurality of hollow heat generating members each made of a ferromagnetic material and having a through-hole, said hollow heat generating members being spaced apart from each other so as to provide at least one array of said hollow heat generating members;
• and
• an electrically conductive wire electrically insulated and extending through said through-hole of said each hollow heat generating member, an alternating current from a power source being applied to said electrically conductive wire, to cause a surface current to flow through a skin layer of said each hollow heat generating member which is located near an inner surface of said through-hole, whereby heat is generating from said skin layer,
• and wherein said at least one array of said hollow heat generating members includes at least one array consisting of a plurality of heat generating tubes each of which has an axial length no more than 20 times an outside diameter thereof.

A surface current heating apparatus, comprising:

• a plurality of hollow heat generating members each made of a ferromagnetic material and having a through-hole, said hollow heat generating members being spaced apart from each other so as to provide at least one array of said hollow heat generating members;
• and
• an electrically conductive wire electrically insulated and extending through said through-hole of said each hollow heat generating member, an alternating current from a power source being applied to said electrically conductive wire, to cause a surface current to flow through a skin layer of said each hollow heat generating member which is located near an inner surface of said through-hole, whereby heat is generating from said skin layer,
• and wherein said at least one array of said hollow heat generating members includes at least one array consisting of a plurality of heat generating members includes at least one array consisting of a plurality of heat generating tubes which are arranged along a substantially entire portion of a closed loop, said electrically conductive wire extending through said each array of said heat generating tubes and along said closed loop, an axial length of a shortest one of said heat generating tubes in said each array being no more than {fraction (1/7)} of a total length of said at least one array of said heat generating tubes.

A surface current heating apparatus, comprising:

• a plurality of hollow heat generating members each made of a ferromagnetic material and having a through-hole, said hollow heat generating members being spaced apart from each other so as to provide at least one array of said hollow heat generating members;
• and
• an electrically conductive wire electrically insulated and extending through said through-hole of said each hollow heat generating member, an alternating current from a power source being applied to said electrically conductive wire, to cause a surface current to flow through a skin layer of said each hollow heat generating member which is located near an inner surface of said through-hole, whereby heat is generating from said skin layer,
• and wherein said at least one array of said hollow heat generating members includes at least one array of heat generating tubes which are axially spaced apart from each other by a distance not larger than three times an axial length of said heat generating tubes.