Abstract: A liquid filled differential pressure detector comprises two pressure sensors. Each sensor is constructed of one or more capsules, which are pairs of diaphragms sealed at their peripheries. The innermost diaphragms are interconnected by a tube which contains a rod assembly. The interior of the sensors and interconnection tube form a sealed volume filled with a incompressible liquid. The rod assembly contacts the outermost diaphragm of the sensors and is displaced by expansion and contraction of the capsules caused by a differential pressure change against the outer surface of the sensors. The motion of the rod assembly is transformed into an electrical signal to indicate the pressure measurement. The apparatus is symmetrical about the center point of the tube to reduce error caused by the fluid's thermal expansion by causing equal and opposite forces to cancel, thereby preventing motion of the rod assembly.

Abstract: A sealed position transducer which is self-wiping and which is readily adaptable for providing both linear and nonlinear electrical outputs. The transducer includes a housing, a resistive element received in the housing, and a flexible membrane, having a conductive portion formed thereon facing the resistive element, disposed over the resistive element and attached to the housing to seal the interior of the housing from the environment. An object whose position is to be sensed or measured is mounted on or connected to a carriage which movably engages a guide track formed as part of the housing. The carriage includes a roller which causes the conductive portion of the membrane to be deflected into contact with a portion of the resistive element.In one embodiment, where a linear relationship between resistance and distance is desired, a resistive element having a known, constant resistance per unit length is used.

Abstract: A remotely actuable switch includes a housing defining a cavity having first and second thermally separated chambers, each enclosing a pair of spaced electrical contacts and each having an associated heating element. An electrically conductive fusible element occupies one of the chambers and electrically bridges the spaced contacts therein. To activate the switch the first heating element is activated to melt the fusible element, allowing a Lorentz force resulting from an applied external magnetic field and from current passing between the bridged contacts to expel the melted fusible material from the first chamber into the second chamber. A helical passage may be used as an alternative to a cavity with discrete chambers.