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Low electromagnetic and electrostatic field radiating heater cable

  • US 5,206,485 A
  • Filed: 10/01/1990
  • Issued: 04/27/1993
  • Est. Priority Date: 10/01/1990
  • Status: Expired due to Fees
First Claim
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1. A low electromagnetic field and low electrostatic field radiating AC-powered heater cable for a personal comfort product such as an electric blanket and the like, comprising:

  • an inner conductor;

    a flexible continuous, intermediate polymer layer enclosing the inner conductor;

    an outer conductor helically wrapped around the intermediate layer with a predetermined number of turns per unit length;

    a conductive polymer layer having a desired low resistivity and which extends around the outer conductor and in electrical contact therewith and covering regions between successive turns of the outer conductor;

    wherein the conductive polymer layer and the number of turns per unit length of the outer conductor are selected to inhibit the radiation of electromagnetic and electrostatic fields from the heater cable, with the number of turns per unit length of the outer conductor being sufficiently high and the resistivity of the conductive polymer being sufficiently low to limit the ESR field to a level of less than about three volts and the EMR field to generally less than about a fraction of a milligauss; and

    an insulative jacket enclosing the conductors and conductive polymer layer.

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