GB562479A - Improvements in or relating to ovens for heating filamentary products - Google Patents

Abstract

562,479. Heating insulation on wires. DALGLEISH, J. W., and PYE, Ltd. Nov. 25, 1942, No. 16725. [Class 39 (iii)] [Also in Group XII] In the baking of enamelled wire by passing it continuously through a heated enclosure, the wire is introduced through a longitudinal slit into the enclosure, which slit is afterwards closed. The oven consists of a pair of quartz rods 1, each with a flat surface 2 and a rectangular channel 3 extending from end to end, so that when the rods are brought together a rectangular enclosure open at both ends is formed. Each rod 1 is secured at the ends to metal blocks 5, 6 carried by insulating brackets 7, 8 hinged at 9 so that the rods may be swung apart to open the oven. The oven is heated by nickel strips 12 laid along the bottom of each channel 3 and connected at the ends to plates 15, 16, the former being fixed and the latter attached to pivoted levers 17 carrying bars 20, 21 connected by springs 22 to brackets 7. The strips 12 are thereby maintained in tension. The bar 20 is provided with a micrometer adjusting screw (not shown) associated with a graduated head 29, whereby a stud 27 may be adjusted along its length to co-operate with a ramp 37 carried by a spring switchcontact blade 38. A fixed contact 40 carried by a bracket 41 is mounted on the insulating member 7. The end blocks 6 are connected by a flexible conductor 44. The linear expansion of the strips 12 relatively to the quartz rods 1, so that at a predetermined temperature stud 27 engages ramp 37 to open the contacts 39, 40, whereby a resistance (not shown) is included in the circuit and the current reduced. The oven halves are drawn together by spring 47 to close the oven, and are separated by a wedge 53 carried by a sliding rod 49. The system may be wholly enclosed to exclude dust, and a wire-breakage indicator may be provided. Conditioned air may be admitted to the oven, and solvent vapour may be recovered. The heating strips 12 may be replaced by metal. channels. The oven may be a nickel tube as described in Specification 557,597, with a longitudinal slit, housed in a quartz jacket with a removable cover for the slit. The oven may alternatively be heated by gas, or by hot air.