| 摘要 |
<p>854,873. Densimeters. NATIONAL RESEARCH COUNCIL. July 15, 1959 [July 29, 1958], No. 24368/59. Class 40 (1). [Also in Group XX] To measure the density of a liquid sample, a vessel 14 is filled with the liquid and shaft 20 rotated so that unbalance causes transverse oscillation of the shaft against the action of springs 35 bearing against a bush 34, the amplitude of oscillation being a measure of the density. This amplitude is measured by means of a rod 58 connected at one end to bush 34 and carrying at its other end a coil 61 cooperating with permanent magnet 63 to produce signals which are amplified and indicated or recorded at 65. Alternatively a crystal pick-up may be employed or electrostatic measurement employed making an element connected to bush 34 one of the plates of a capacitor. In a modification the amplitude of oscillation is measured by optical means or the coil-springs 35 are replaced by leaf-springs and a strain gauge is attached to one of the springs. The vessel 14 is pivoted at 15 in plates 16, adjusting screws 18, 21 being provided so that on filling the vessel 14 with pure water and rotating the shaft 20 at constant speed, the system may be made to balance so that the amplitude of oscillation is zero. Closure 29 is then removed, pivoted flaps 52, 56 raised, and vessel 14 tilted anticlockwise to empty the water into a waste pipe 54. The vessel 14 is tilted back to its normal position, filled with sample liquid and closure 29 replaced, the assembly then being rotated through shaft 20 at the constant speed and the magnitude of oscillation observed. A valve 26 allows flushing out the vessel 14 between samples.</p> |
