| 摘要 |
PURPOSE:To always stably and accurately control the quantity of discharge by directly detecting the mechanical vibration of the moving part of a piezoelectric pump by means of a displacement sensor, and converting this into a d.c. voltage for comparing this with a reference voltage, and on the basis of the result of comparison, by controlling the intensity of the a.c. signal for driving a movable part. CONSTITUTION:The a.c. signal from an oscillator 18 passes through an electronic volume 34, and is amplified by an amplifier 19, and then this is converted into mechanical vibration by a piezoelectric actuator 12, and the displacement of the mechanical vibration is enlarged by an enlarging mechanism 16. The mechanism 16 vibrates a diaphragm 9 to forcibly feed the fluid from a piezoelectric pump 1. When the reactive pressure of a forcibly feeding device changes with the lapse of time, the vibration of the diaphragm 9 also changes. A change sensor 27 senses the vibration of a steel plate 28 being vibrated together with the diaphragm 9, and outputs an electric signal. This signal is detected by the detection part of a sensor driving part 30, and is compared with a reference voltage by means of a comparator 32. On the basis of the comparison result, the electronic volume 34 controls the intensity of the a.c. signal, thus, the amplitude of the mechanism 16, or the diaphragm 9 can be controlled. |
