POSITION DETECTING DEVICE

摘要

PURPOSE:To improve detecting accuracy, by imparting minute sine wave vibration so that hysteresis does not appear in the average value of the pressure. CONSTITUTION:A liquid well 6 having a wide opening is connected to a flexible hose 8 through an orifice 14. The upper part of the hose 8 is connected to an upper pressure detector 12 through an upper branching pipe 15. The lower end of the hose 8 is connected to a lower pressure detector 9. A vibration pressure generator 16 is connected to the hose 8. Its diaphragm generates vibration pressure by exciting an electromagnet 17 by an oscillator 18. The polarity of the output of a lower sensor is inverted by an inverting amplifier 19. Then the difference between the output and the output of an upper sensor is amplified by a differential amplifier 20. The AC component of the oscillator frequency is removed by a filter 21. Then the result is read by a digital voltmeter 22.