GB833045A - Improvements in or relating to flexible electric heaters - Google Patents

Abstract

833,045. Flexible electric heaters. ELECTROTHERMAL ENGINEERING Ltd. July 24, 1958 [April 24, 1957], No. 13069/57. Class 39(3) A flexible electric heater, e.g. for heating a pipe, comprises a plurality of parallel rows of overlapping insulating blocks, e.g. of sintered aluminium oxide, each block being so constructed that the element can be located therein other than by threading through the block. As shown, upwardly directed U-shaped blocks 1 alternate in each row with inverted U-shaped blocks 2, each two adjacent blocks being spaced apart by a portion of a block in the next adjacent row and adjacent blocks at the outer edges of the heater being spaced apart by spacing members 4. Wires or bars 5 threaded through aligned holes 3 in the blocks hold the assembly together. The blocks 1 and 2 are so constructed that the base of the U of each block 2 lies above the plane of the base of the U of the adjacent block 1 so that a clear passageway is left along each row of blocks for a strip heating element 6. A block 8 (Figs. 8 to 10, not shown) is provided where the element 6 has to reverse direction in passing from one row to the next, and a block 7 serves as a termination block for connection to an external circuit. At least one of the engaging surfaces of the blocks 1 and 2 may be rounded to facilitate flexure of the heater. The blocks may be in the form of a Greek cross (Fig. 4, not shown) or a Z (Fig. 6, not shown). One face of the heater may be covered with a mat of heat insulating material, e.g. glass fibres.