| 摘要 |
PROBLEM TO BE SOLVED: To enable accurate density measurement, in a magnetic levitation densimeter. SOLUTION: By magnetically levitating a ferromagnetic body 15 fixed to the upper end of a load change member 12 with a hybrid magnet 05 formed by combining an electromagnet suspended from an electronic balance and a permanent magnet, a tare-weighing position at which only the load change member 12 is magnetically levitated and a weight-weighing position at which the load change member 12 supporting a weight 07, having known density and volume is magnetically levitated are selectively levitation-controlled, and the weight at that time can be measured with the electronic balance 16 via a partition 02 in a non-contact state. The position of the load change member 12 is detected by a position sensor 10, and it can be levitated to a stable position by zero power control. By the use of such a mechanism, the difference in the effects of the magnetic force received by fluid between the tare weighing position and the weight weighing position can be reduced, and the effect of the transmission error on the force due to the magnetism of the fluid can be minimized, so that precise density measurement is enabled. COPYRIGHT: (C)2006,JPO&NCIPI
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