Electrical heating element, its manufacture and use

A radiant electric heater comprising a base of thermal and electrical insulation material and an electrical heating element partially embedded therein, the electrical heating element comprising an elongate electrically conductive strip comprising an elongate continuous portion and a discontinuous portion substantially co-extensive with the continuous portion, the discontinuous portion comprising a plurality of mounting tabs extending in a direction away from the continuous portion at spaced-apart locations, the tabs being secured on or in the base, there being provided in each tab at least one aperture, whereby thermal conduction into the tabs from the continuous portion is reduced or minimised and also variation in electric current density along the continuous portion of the strip, when energised, is reduced or minimised.

A radiant electric heater comprising a base of thermal and electrical insulation material and an electrical heating element partially embedded therein, the electrical heating element comprising an elongate electrically conductive strip comprising an elongate continuous portion and a discontinuous portion substantially co-extensive with the continuous portion, the discontinuous portion comprising a plurality of mounting tabs extending in a direction away from the continuous portion at spaced-apart locations, the tabs being secured on or in the base, there being provided in each tab at least one aperture, whereby thermal conduction into the tabs from the continuous portion is reduced or minimised and also variation in electric current density along the continuous portion of the strip, when energised, is reduced or minimised, wherein a plurality of spaced-apart tabs in at least one selected region of the heating element are replaced by a single elongate tab extending along the at least one selected region without an aperture formed therein to achieve a localised increase in the cross-sectional area over a predetermined length of the conductive strip such that the at least one selected region operates at a lower temperature and/or with a lower visible radiance than the remainder of the element.

An electrical heating element for a radiant electric heater, the element comprising an elongate electrically conductive strip adapted for edgewise mounting on a base of thermal and electrical insulation material, the strip comprising an elongate electrically conductive strip comprising an elongate continuous portion and a discontinuous portion substantially co-extensive with the continuous portion, the discontinuous portion comprising a plurality of mounting tabs extending in a direction away from the continuous portion at spaced-apart locations, for securement in or to the base, there being provided in each tab a single hole, whereby thermal conduction into the tabs from the continuous portion is reduced or minimised and also variation in electric current density along the continuous portion of the strip is reduced or minimised when the strip is electrically connected for operation in a radiant electric heater.

An electrical heating element for a radiant electric heater, the element comprising an elongate electrically conductive strip adapted for edgewise mounting on a base of thermal and electrical insulation material, the strip comprising an elongate electrically conductive strip comprising an elongate continuous portion and a discontinuous portion substantially co-extensive with the continuous portion, the discontinuous portion comprising a plurality of mounting tabs extending in a direction away from the continuous portion at spaced-apart locations, for securement to or in the base, there being provided in each tab at least one aperture, whereby thermal conduction into the tabs from the continuous portion is reduced or minimised and also variation in electric current density along the continuous portion of the strip is reduced or minimised when the strip is electrically connected for operation in a radiant electric heater, wherein the at least one aperture is omitted from the tabs in at least one selected region of the heating element to achieve a localised increase in cross-sectional area over a predetermined length of the conductive strip such that the at least one selected region operates in a heater at a lower temperature and/or with lower visible radiance than the remainder of the element.

An electrical heating element for a radiant electric heater, the element comprising an elongate electrically conductive strip adapted for edgewise mounting on a base of thermal and electrical insulation material, the strip comprising an elongate electrically conductive strip comprising an elongate continuous portion and a discontinuous portion substantially co-extensive with the continuous portion, the discontinuous portion comprising a plurality of mounting tabs extending in a direction away from the continuous portion at spaced-apart locations, for securement to or in the base, there being provided in each tab at least one aperture, whereby thermal conduction into the tabs from the continuous portion is reduced or minimised and also variation in electric current density along the continuous portion of the strip is reduced or minimised when the strip is electrically connected for operation in a radiant electric heater, wherein an additional piece of electrically conductive material is bonded to the strip in at least one selected region of the heating element to locally increase the thickness of the strip to achieve a localised increase in cross-sectional area over a predetermined length of the conductive strip such that the at least one selected region operates in a heater at a lower temperature and/or with lower visible radiance than the remainder of the element.

A radiant electric heater comprising a base of thermal and electrical insulation material and an electrical heating element partially embedded therein, the electrical heating element comprising an elongate electrically conductive strip comprising an elongate continuous portion and a discontinuous portion substantially co-extensive with the continuous portion, the discontinuous portion comprising a plurality of mounting tabs extending in a direction away from the continuous portion at spaced apart locations, the tabs being secured on or in the base, there being provided in each tab a single hole, whereby thermal conduction into the tabs from the continuous portion is reduced or minimised and also variation in electric current density along the continuous portion of the strip, when energised, is reduced or minimised.

A radiant electric heater comprising a base of thermal and electrical insulation material and an electrical heating element partially embedded therein, the electrical heating element comprising an elongate electrically conductive strip comprising an elongate continuous portion and a discontinuous portion substantially co-extensive with the continuous portion, the discontinuous portion comprising a plurality of mounting tabs extending in a direction away from the continuous portion at spaced-apart locations, the tabs being secured on or in the base, there being provided in each tab at least one aperture, whereby thermal conduction into the tabs from the continuous portion is reduced or minimised and also variation in electric current density along the continuous portion of the strip, when energised, is reduced or minimised, wherein the at least one aperture is omitted from the tabs in at least one selected region of the heating element to achieve a localised increase in cross-sectional area over a predetermined length of the conductive strip such that the at least one selected region operates at a lower temperature and/or with lower visible radiance than the remainder of the element.

A radiant electric heater comprising a base of thermal and electrical insulation material and an electrical heating element partially embedded therein, the electrical heating element comprising an elongate electrically conductive strip comprising an elongate continuous portion and a discontinuous portion substantially co-extensive with the continuous portion, the discontinuous portion comprising a plurality of mounting tabs extending in a direction away from the continuous portion at spaced-apart locations, the tabs being secured on or in the base, there being provided in each tab at least one aperture, whereby thermal conduction into the tabs from the continuous portion is reduced or minimised and also variation in electric current density along the continuous portion of the strip, when energised, is reduced or minimised, wherein an additional piece of electrically conductive material is bonded to the strip in at least one selected region of the heating element to locally increase the thickness of the strip to achieve a localised increase in cross-sectional area over a predetermined length of the conductive strip such that the at least one selected region operates at a lower temperature and/or with lower visible radiance than the remainder of the element.