Application Cases

Experiment Name: Application of Power Amplifiers in Flow Rate Testing of Compliant Valve Piezoelectric Pumps

Research Direction: Electronics

Test Objective:
The amplitude variation of the piezoelectric vibrator used in compliant valve piezoelectric pumps directly influences the volume of the pump chamber, as theoretical analysis indicates a positive correlation between amplitude and volumetric change. Consequently, changes in the pump chamber's volume directly affect the pump's output flow rate. Therefore, flow rate characteristics are a critical performance metric for piezoelectric pumps, necessitating research on their optimal driving conditions.

Test Equipment:
Signal generator, ATA-308 power amplifier, oscilloscope for monitoring input signals, prototype of the compliant valve piezoelectric pump, beakers for containing fluid, and an electronic balance for measuring mass.

Experimental Procedure:

1. Use a syringe to fill the silicone tubing and the prototype pump with water, ensuring the removal of any internal air bubbles. If air bubbles persist in the pump chamber, flow channels, or silicone tubing, clean the interior with alcohol before refilling with water.

2. To minimize the influence of the siphon effect during the experiment, use beakers with a large diameter and maintain the liquid levels in both beakers at the same height.

3. Conduct the tests within a short timeframe to reduce unnecessary experimental errors.

Experimental Results:
The relationship between flow rate, voltage, and frequency of the prototype pump is illustrated in the experiments. At voltages of 40V, 60V, 80V, and 100V, the maximum flow rates are 22.03 mL/min, 55.78 mL/min, 89.02 mL/min, and 119.61 mL/min, respectively, all occurring at a frequency of 25 Hz.

Figure 1 demonstrates that the flow rate versus frequency curves exhibit similar trends under different voltages. On one hand, within the frequency range of 10–25 Hz, the flow rate shows an almost positive correlation with frequency, increasing as frequency rises. On the other hand, within the frequency range of 25–40 Hz, the flow rate gradually decreases as frequency increases. The observed trend of flow rate first rising and then falling in the 10–40 Hz frequency range is primarily attributed to the amplitude variation of the piezoelectric vibrator with frequency.

Among the tested input signals, the maximum flow rate is achieved at 100V and 25 Hz. When the voltage is below 60V and the frequency is below 15 Hz, the flow rate is nearly always less than 5 mL/min.

Figure 2 illustrates that, regardless of whether the frequency is 20 Hz, 25 Hz, or 30 Hz, higher voltages result in greater flow rates. In summary, within the voltage range of 40–100V, the relationship between voltage and pump flow rate is almost positively correlated. The flow rate increases with higher voltages, and the overall trend of flow rate variation with frequency aligns closely with the amplitude variation trend.

Figure 1: Flow Rate-Frequency Characteristics Under Different Voltages

Figure 2: Flow Rate-Voltage Characteristics Under Different Voltages

Figure: ATA-308C Power Amplifier Specifications and Parameters