Abstract: A pressure sensor includes an outer body defining a sensor cavity and a resonator element located at least partially within the sensor cavity. The pressure sensor also includes a bellows having an outer side and an inner side and that is located at least partially within the outer body. the inner side of the bellows defines an internal volume and is configured to receive a measured fluid into the internal volume. The pressure sensor also includes a measuring fluid filling at least a portion of an area between the outer side and the outer body.

Abstract: A pressure sensor includes an outer body defining a sensor cavity and a resonator element located at least partially within the sensor cavity. The pressure sensor also includes a bellows having an outer side and an inner side and that is located at least partially within the outer body. the inner side of the bellows defines an internal volume and is configured to receive a measured fluid into the internal volume. The pressure sensor also includes a measuring fluid filling at least a portion of an area between the outer side and the outer body.

Abstract: A differential pressure monitoring device utilizing two crystalline frequency sensors exposed to different pressures for generating two signals which are combined by a frequency mixer. Two offset based frequency crystal sensors are each exposed to different pressures and the resulting frequencies are mixed to measure the pressure differential between the two crystals. When the crystals are exposed to a common pressure, the crystals have an offset based frequency response that is consistent with pressure. When the two crystals are exposed to pressures, the offset frequencies are mixed together to create a differential frequency that is precisely related to the differential in the pressures placed on the two different crystal sensors.

Abstract: An apparatus particularly adaptable for recording pressure of subterranean formations in a downhole pressure gauge by providing a variable capacitance in response to changes in ambient pressure. The apparatus comprising a closed tubular housing having a deformable conductive end with an interior and exterior surface, the deformable end forming a diaphragm subject to the pressure in which the housing is positioned, increased pressure deflecting the deformable end inwardly. The deformable end has an axial boss portion extending inwardly from the inner surface. A stator having a central hub is positioned within the housing, the hub having an opening therein which receives the boss portion.

Abstract: Apparatus for digitally recording the value of pressure and temperature, or other parameters, in a borehole logging instrument. In one embodiment the values of the earth parameter are converted to an A.C. signal, the frequency of which is a function of the value of the parameter. Clock means are provided for presenting, at selected time intervals, voltage pulses of selected short time length. The A.C. signal is gated to a counter for the selected short interval of time, and the count of the counter becomes a measure of the parameter. Solid state memory means are provided, and the output of the counter in the form of binary bits is stored in the memory. Means are provided for retrieving the instrument and reading out of the memory the binary bits as stored.

Abstract: A gauge for remotely indicating the pressure in a subterranean formation penetrated by a bore hole, including a tubular closed housing, the lower end of the closed housing forming an integral diaphragm which is subjected to the pressure of the subterranean formation, the housing having an internal reduced diameter portion adjacent the diaphragm forming an integral circumferential ledge, a cup shaped stator element having a closed bottom and opened top, the external diameter of the stator element being slightly less than the internal diameter of the housing and having an enlarged external diameter lip which engages the internal ledge of the tubular housing to precisely position the stator element relative to the diaphragm, the stator element having a conductive surface on the lower end thereof spaced adjacent to the diaphragm forming therebetween a capacitive relationship responsive to pressure deflection of the diaphragm, means of connecting the end of the housing opposite the diaphragm to a conductive cable