Abstract: A method of making a conductive polymer sheet in which a hollow conductive polymer extrudate is slit and flattened. The resulting sheet may have improved resistivity uniformity over conventionally extruded sheet. The sheet is useful in producing electrical devices such as heaters and circuit protection devices.

Abstract: Electrical systems, especially elongate heating systems, include means for monitoring circuit continuity and/or absence of ground faults. The systems comprise a switching device, e.g. a thermostat, as well as a circuit breaker. When the switching device is on, a relatively high current passes through the circuit and when it is off, little or no current passes through the circuit. In one embodiment, a small controlled residual current flows in the circuit even when the switching device is off, and a current-detecting device signals when a discontinuity causes the current to drop below the expected value for the residual current. In another embodiment, the switching device is placed so that the heater (or other electrical load) is at a positive potential with respect to ground even when the switching device is off, and a ground fault indicator is used to compare the currents in the two legs of the circuit and to signal when a ground fault causes the currents to differ.

Abstract: A method for manufacturing a laminar flow control aircraft structure, typically a wing or other aerodynamic surface, having an outer skin in which a plurality of spanwise oriented and chordwise spaced recesses have been machined. The method includes the installation of a strip of slot assembly tape in each of said recesses, preferably with an adhesive, and the removal of an element of the tape called a cover plate to expose a spanwise slot through which boundary layer air can be drawn. Also disclosed is a slot assembly tape having a protective cover plate and a pair of sidewalls, and a laminar flow control aircraft structure, typically a wing, in which the slot assembly tape has been employed.