Abstract: A resonant sensor 1908 is used to determine fluid properties, the resonant sensor 1908 comprising a resonator 108 defining a lengthwise axis and having a central vibrational node (140), and a pair of opposed lengthwise end-portions (125); a support structure including a frame (115) and a set of flexible supports (110) extending from the frame to the central vibrational node and thereby supporting the resonator at the lengthwise midpoint; a driving and sensing assembly, adapted to drive the resonator to resonant motion and to sense resultant motion of the resonator and producing a motion sensed signal, responsive thereto; and a control and signal processing network adapted to control the driving and sensing assembly to drive the lengthwise end-portions in rotation about the lengthwise axis, in opposed rotational directions, and responsive to the motion sensed signal to determine at least one fluid property of a fluid under test in response to the motion sensed signal.

Abstract: A resonant sensor 1908 is used to determine fluid properties, the resonant sensor 1908 comprising a resonator 108 defining a lengthwise axis and having a central vibrational node (140), and a pair of opposed lengthwise end-portions (125); a support structure including a frame (115) and a set of flexible supports (110) extending from the frame to the central vibrational node and thereby supporting the resonator at the lengthwise midpoint; a driving and sensing assembly, adapted to drive the resonator to resonant motion and to sense resultant motion of the resonator and producing a motion sensed signal, responsive thereto; and a control and signal processing network adapted to control the driving and sensing assembly to drive the lengthwise end-portions in rotation about the lengthwise axis, in opposed rotational directions, and responsive to the motion sensed signal to determine at least one fluid property of a fluid under test in response to the motion sensed signal.

Abstract: A fluid density measurement device that includes a housing, defining a chamber and an aperture; a resonator having length that is at least 5 times greater than its smallest diameter and having a longitudinal axis and a nodal plane, transverse to the longitudinal axis. The resonator further includes a tube having a first end and a second end; a second-end closure, closing the second end; and a drive rod centrally attached to the second-end closure and extending to the tube first end. Further, the device includes a resonator transducer assembly and the resonator is sealingly joined to the aperture at the nodal plane, so that an enclosed portion extends into the chamber and an exposed portion extends outside of the chamber, and wherein the chamber tends to assume the temperature of the exposed resonator portion, causing the resonator to be isothermal.

Abstract: A fluid density measurement device (8) that includes a housing (54), defining a chamber (18) and an aperture; a resonator (10?) having length that is at least 5 times greater than its smallest diameter and having a longitudinal axis and a nodal plane, transverse to the longitudinal axis. The resonator further includes tube (44) having a first end and a second end; a second-end closure (52), closing the second end; and a drive rod (48) centrally attached to the second-end closure and extending to the tube first end. Further, the device includes a resonator transducer assembly (22) and the resonator is sealingly joined to the aperture at the nodal plane, so that an enclosed portion (10A?) extends into the chamber and an exposed portion (10B?) extends outside of the chamber, and wherein the chamber tends to assume the temperature of the exposed resonator portion, causing the resonator to be isothermal.