Abstract: A fume detector including a gas sensor having a heater element and a variable impedance element associated therewith whose impedance decreases in the presence of toxic gases or fumes, or a decrease of free oxygen in an atmosphere being monitored. A load resistor in series circuit with the gas sensor and a pair of series connected potentiometers in parallel circuit with the gas sensor and the load resistor form a Wheatstone bridge. A first voltage comparator connected to one of the potentiometers and a reference voltage provides a signal when the supply voltage decreases below a predetermined level. A second voltage comparator connected to the other potentiometer and a junction between the gas sensor and the load resistor provides a signal when the gas sensor fails in the open circuit condition. A third voltage comparator connected across the bridge provides a signal when a toxic gas condition exists.

Abstract: A housing for magnetic particle devices comprising first and second housing members adopted to be assembled in side-by-side axial relation, at least one of said housing members having an annular cavity formed extending inwardly on one side thereof adjacent to the other housing member, an annular tapered surface formed on the side of one of said housing members at an intermediate location radially of the annular cavity and a sidewardly extending annular flange formed on the other housing member for engaging the annular tapered surface to divide the annular cavity into inner and outer cavity portions when the first and second housing members are connected, the annular flange separating the cavity into separate portions on opposite sides thereof, and members connecting the first and second housing members together whereby the annular flange moves axially against and is deformed by engagement with the annular tapered surface to seal between the separate cavity portions.

Abstract: A tension control system for use with a device which includes at least one roll over or around which a web or strand of material passes, a tension responsive transducer associated with the roll, a reference tension selector, a drive unit for effecting movement of the web or strand over or around the roll, and a tension controller associated with a tension control roll, the tension controller responsive to the outputs of the transducer and of the reference tension selector for controlling the torque applied to the tension control roll in order to control tension on the web or strand, the improvements comprising a control circuit connected between the transducer and the tension controller including an error limiter circuit responsive to the outputs of the transducer and of the reference tension selector to produce an error signal, the control circuit having circuit elements responsive to the error signal and connected to vary the torque applied to the torque control roll in a manner to maintain the web or stran

Abstract: An apparatus for measuring and monitoring the tension on a web or strand as it extends and/or moves over and around a roll including a support assembly for supporting at least one end of the roll, said support assembly including a bridge structure having spaced connected bridge portions aligned with the roll on opposite sides of the axis thereof, a mounting member attached to anchor one end of the bridge structure in fixed position, a diaphragm member attached to the opposite end of the bridge structure, a mounting structure for attaching the diaphragm member to the roll, at least two and preferably four strain sensitive gage members attached to one of said spaced connected bridge portions, and a bridge type electric circuit including circuit connections to said strain sensitivie gage members.