Application Cases

Experiment Name: Application of High-Voltage Amplifiers in Acid-Resistant Ultrasonic Transducers

Experiment Purpose:
To design and fabricate an ultrasonic transducer for descaling in highly acidic fluid systems. The study utilized a static fluid ultrasonic field strength testing system assembled with polypropylene pipelines to investigate factors affecting ultrasonic propagation.

Experiment Equipment:
Function generator, ATA-4011 high-voltage power amplifier, digital oscilloscope, ultrasonic detector, ultrasonic vibration system, etc.

Experiment Process:

(1) Design and Fabrication of the Ultrasonic Transducer:
The external structure of the transducer is shown in the figure below. The large-head screw is fixed along the central axis of the concave pit of the acid-resistant ceramic ultrasonic emitter, ensuring a tight connection between the ceramic and the screw. All components in the diagram are sealed and tightly connected. The support and sealing plates are made of acid-resistant polypropylene plastic, while the acid-resistant gaskets are made of polytetrafluoroethylene.

(2) Testing of Ultrasonic Emission Field Strength of the Transducer:
A static pipeline ultrasonic field strength testing system was designed and assembled, as shown in the figure below. The medium used was a 1.0 mol/L zinc sulfate solution or selected concentrations of highly acidic aqueous solutions. This system was used to test and compare the ultrasonic emission intensity of the designed transducer with that of a conventional transducer using a stainless steel emitter. For ease of characterization, both transducers were of the same dimensions, emission power, and operating frequency. Since the acoustic field strength is proportional to the electrical signal strength measured by the ultrasonic sensor, a self-made high-sensitivity composite piezoelectric sensor was used to measure voltage as a substitute for acoustic field strength in comparative analysis.

The sinusoidal wave generated by the function signal generator was amplified by the ATA-4011 high-voltage amplifier to drive the transducer.

(3) Acid Corrosion Testing:
Aqueous solutions of H₂SO₄, HCl, HNO₃ with concentrations of 0.05 mol/L, 0.1 mol/L, 0.2 mol/L, 0.5 mol/L, and 1.0 mol/L, as well as HF solutions with concentrations of 0.05 mol/L, 0.1 mol/L, 0.2 mol/L, and 0.5 mol/L, were prepared. The zinc sulfate solution in the testing system was replaced with solutions of varying acidity (H₂SO₄, HCl, HNO₃, or HF). The ultrasonic descaler was then connected to the ultrasonic generator for a one-month test. After the test, the ultrasonic transducer was disassembled to observe the corrosion level of the ceramic ultrasonic emitter.

Experiment Results:
The acoustic field strength of the ceramic ultrasonic emitter was significantly higher than that of the stainless steel emitter. This phenomenon can be attributed to differences in vibration modes. The vibration node of the former is at the support point, allowing greater freedom at the ceramic end, while the latter drives the stainless steel plate with limited freedom. Additionally, the ceramic ultrasonic emitter has lower density, higher rigidity, and significantly lower acoustic impedance compared to stainless steel, which facilitates ultrasonic transmission into the saline liquid.

The results indicate that the ceramic ultrasonic emitter is more conducive to ultrasonic propagation, and the effectiveness of ultrasonic transmission improves with an increase in the diameter of the thick end of the waveguide (i.e., the effective transmission area). Combined with finite element software analysis, designing the support point at the vibration node of the transducer is beneficial for transmitting acoustic waves into the liquid phase.

Figure: ATA-4011C High-Voltage Power Amplifier Specifications and Parameters