Abstract: A transducer pressure crystal having improved thermal coupling with the environment external to a pressure housing in which the crystal is disposed. A cylindrical major portion of the side wall of the pressure crystal is located immediately adjacent an inner wall of a chamber within the pressure housing, separated therefrom only by dimensional tolerances sufficient to ensure that the crystal is surrounded by pressure-transmitting fluid exposed to pressure from the external environment. The thermal time constant of the transducer for external temperature changes is significantly decreased. The time constant of the transducer for temperature changes in the pressure-transmitting fluid produced by rapid pressure changes is similarly decreased. A thin, electrically insulating element may optionally be disposed between the crystal side wall and the inner wall to preclude electrical grounding of the crystal to the housing.

Abstract: A pressure transducer assembly for measuring fluid pressure. The transducer assembly includes a thickness-shear mode resonator pressure sensor and a thickness-shear mode resonator temperature sensor for temperature compensation of the pressure sensor. Both sensors are exposed to the pressurized fluid, and possess similar thermal time constants. The temperature sensor possesses a pressure sensitivity less than that of the pressure sensor, and a temperature sensitivity greater than that of the pressure sensor. The pressure and temperature sensors may be of similar size and configuration, and may be fabricated from the same material, such as quartz.

Abstract: A pressure transducer including a first pressure crystal, a second temperature crystal, a third reference crystal and associated electronics. All three crystals resonate in the thickness-shear mode.

Abstract: A vibratory temperature transducer includes a pair of elongate, generally parallel bars coupled together at one end in a type of tuning fork arrangement. The bars each have a thickness of t, a width of w and a length between free and fixed ends of L. The distance between the free end and the point where the bars are coupled together is m. Apparatus is provided to cause the bars to vibrate in torsional opposition, where the frequency of vibration is generally a function of temperature. Apparatus is also provided for determining the frequency of vibration of the bars so that when the bars are subjected to a change in temperature, the temperature can be readily determined by simply determining the magnitude of the frequency change. By careful determination of the dimensions L, m, t and w, spurious modes of oscillation of the transducer, which cause a reduction in the mechanical Q and thus an erroneous reading of temperature, are avoided.

Abstract: A transducer system for a weighing scale having a flexure mode crystal resonator includes a parallelogram linkage for supporting the load platform of the scale, a mounting structure for mounting the crystal resonator between two pivotally connected mounting arms, and a coupling assembly for coupling force from the parallelogram linkage to one arm of the mounting structure.