Abstract: A signal isolator for providing at an output thereof representations of input currents from a source provided in an input conductor supported on a substrate having a bridge circuit suited for electrical connection to a source of electrical energization with a pair of series circuit members electrically connected in parallel with one another supported on a substrate with each series circuit member having a magnetoresistive member electrically connected in series with a current value controller, controlled at a controller terminal, at an output terminal of that controller. Each magnetoresistive members is electrically isolated from the input conductor and has a resistance versus applied external magnetic field characteristic that is substantially linear for at least relatively small externally applied magnetic fields.

Abstract: A self-cooled high-temperature fan apparatus for use in displacing high-temperature gases and atmospheres, such as the atmosphere within a high-temperature furnace. The preferred fan includes a frame supporting the fan. One or more bearings rotatably support a fan shaft. A fan element is supported by the fan shaft. Heat transfer through the fan and fan shaft is limited by an air-flow passageway and ports provided in the fan shaft and induction apparatus for inducing air flow through the passageway and ports as the fan shaft rotates. The fan apparatus is configured to limit heat transfer through the fan apparatus without the need for separate fan-cooling apparatus thereby preventing bearing damage and generally increasing the fan's operational life.

Abstract: This invention comprises high temperature fan apparatus for use in displacing high-temperature gases and atmospheres, such as the atmosphere within a high-temperature furnace. The fan apparatus is configured to limit heat transfer through the fan apparatus without the need for separate fan-cooling apparatus thereby preventing bearing damage and generally increasing the fan's operational life. The preferred fan includes a frame supporting the fan. One or more bearings rotatably support a fan shaft. A fan element is supported by the fan shaft, The fan element may be within the furnace interior. Heat transfer through the fan and fan shaft is limited by at least one bore positioned in at least a portion of the fan shaft. Heat transfer through the fan is further limited by thermal barrier material secured with respect to the frame. Oversized bearing structure may additionally be provided to further limit heat transfer from the fan shaft to the bearings.