Electrical heating unit with flattened embedded heating coil

Claim 2

An electric heating unit comprising: a form-retaining ceramic fiber insulating body having a heat-radiating surface; an elongate resistance heating coil of wire having a plurality of turns at least substantially fully embedded in situ in the ceramic fiber material of said insulating body along said heat-radiating surface; each turn of said coil being formed with a substantially linear first segment lying generally parallel to and closely adjacent said surface of said insulating body, in contact with said ceramic material at least substantially along the entire length of said first segment, and a second segment lying generally parallel to said surface wholly within said body at a predetermined distance from said first segment; the portion of said heat-radiating surface immediately adjacent and extending alongside said first coil segment being substantially linear in a direction parallel to said first segment; the lateral dimension of each turn of said coil in a direction parallel to said first segment being greater than said predetermined distance; and means extending from said insulating body making electrical connection to the ends of said heating coil.

Claim 3

The electric heating unit as claimed in claim 1, wherein said second segment of said coil is a substantially linear segment identical to said first segment.

Claim 4

An electric heating unit comprising: a form-retaining insulating body comprised of a mass of insulating material and having a heat-radiating surface; a resistance heating coil of wire having a plurality of consecutive turns at least substantially fully embedded in said material of said insulating body along said heat-radiating surface; each of the turns of said coil being formed to provide a configuration wherein each turn includes (1) a substantially linear first segment lying generally in said heat-radiating surface of the insulating body, in contact with said insulating material at least substantially along the entire length of said first segment, and (2) a substantially linear second segment lying generally parallel to said first segment wholly within said body and in contact with said insulating material along the entire length of the segment; the portion of said heat-radiating surface immediately adjacent and extending alongside said first coil segment being substantially linear in a direction parallel to said first coil segment; the lateral dimension of each turn of said coil in a direction parallel to said first and second segments being greater than the distance said second segment is set in from said first segment; and means extending from said insulating body making electrical connection to the ends of said heating coil.

Claim 5

An electric heating unit comprising: a form-retaining insulating body comprised of a mass of insulating material and having a heat-radiating surface; a resistance heating coil of wire having a plurality of consecutive turns at least substantially fully embedded in said material of said insulating body along said heat-radiating surface; each of the turns of said coil being formed to provide a configuration wherein each turn includes (1) a substantially linear first segment lying generally in said heat-radiating surface of the insulating body, in contact with said insulating material at least substantially along the entire length of said first segment, and (2) a substantially linear second segment lying generally parallel to said first segment wholly within said body and in contact with said insulating material along the entire length of the segment; the portion of said heat-radiating surface immediately adjacent and extending alongside said first coil segment being substantially linear in a direction parallel to said first coil segment; the lateral dimension of each turn of said coil in a direction parallel to said first and second segments being greater than the distance said second segment is set in from said first segment; and means extending from said insulating body making electrical connection to the ends of said heating coil.

Claim 6

The electric heating unit as claimed in claim 3, wherein the thickness of said insulating body is no greater than about twice the depth of said resistance heating coil within said insulating body.

Claim 7

An electrical heating unit comprising: a form-retaining insulating body formed of a mass of insulating material and having a heat-radiating surface; a resistance heating coil of wire comprising a plurality of consecutive ovalized turns all at least substantially fully embedded in said insulating body along said heat-radiating surface; each turn of said coil having a major axis and a minor axis transverse to and smaller than said major axis, the major axis of each of said ovalized heating coil turns being generally parallel to the portion of said surface of said insulating body which is immediately adjacent such turn, and being within said body at a predetermined distance from said surface; each turn of said coil having an outer segment which is generally parallel to said portion of said surface and lying generally in said surface so that said outer segment is at least partly surrounded by and in intimate contact with said insulating material along at least substantially the entire length of said outer segment; each turn of said coil having a second segment directly opposite the first segment of that turn and set in from said body surface at a depth corresponding to said minor axis and in intimate contact with said insulating material; and means extending from said insulating body making electrical connections to the ends of said heating coil.

Claim 8

An electrical heating unit comprising: a form-retaining insulating body formed of a mass of insulating material and having a heat-radiating surface; a resistance heating coil of wire comprising a plurality of consecutive ovalized turns all at least substantially fully embedded in said insulating body along said heat-radiating surface; each turn of said coil having a major axis and a minor axis transverse to and smaller than said major axis, the major axis of each of said ovalized heating coil turns being generally parallel to the portion of said surface of said insulating body which is immediately adjacent such turn, and being within said body at a predetermined distance from said surface; each turn of said coil having an outer segment which is generally parallel to said portion of said surface and lying generally in said surface so that said outer segment is at least partly surrounded by and in intimate contact with said insulating material along at least substantially the entire length of said outer segment; each turn of said coil having a second segment directly opposite the first segment of that turn and set in from said body surface at a depth corresponding to said minor axis and in intimate contact with said insulating material; and means extending from said insulating body making electrical connections to the ends of said heating coil.