| 摘要 |
<p>1,143,050. Measuring physical properties electrically. AUTOMATION PRODUCTS Inc. July 17, 1967 [July 22, 1966], No.32794/67. Heading G1N. In apparatus for measuring e.g. viscosity, density &c. of a fluid by the frequency or amplitude of vibration of a rod protruding through a support in a wall of the container into the fluid, the damping effect of the support is effectively obviated by making the natural resonant frequencies of the probe inside the container and the housing outside the container equal, and the torque each exerts on the support is also made equal. The probe comprises an elongated tubular part 111 Fig. 2 protruding through support 20 in the wall 21 of the container. The outer end has a transverse member carrying armatures 56, 58 at the extremities in a housing 12, wherein the former co-operates with an A. C. -energized coil 36 to produce vibration, and the latter co-operates with a permanent magnet 42 and coil 38 to produce an output voltage whose amplitude and frequency represent the vibrations of the assembly. The resonant frequency of the housing 12 is lowered by adding a weight 100 and elongating the neck 102 to make it equal to that of the vibrating means 111; the bending moments at the support are made equal by appropriate mechanical design. The coils 36, 38 are incorporated in an oscillatory circuit to maintain vibrations at the common natural resonant frequency, with meters to monitor the frequency and amplitude of vibration.</p> |
