Digital Ultrasonic Sound Level Meter

Description

The intensity of ultrasound, also known as acoustic power, within a liquid sound field is a crucial factor in ultrasonic systems. It directly affects the cleaning performance of cleaning equipment and the efficiency of ultrasonic processors. A sound intensity meter allows for quick and convenient measurement of the sound field intensity at any time and place, displaying the acoustic power value clearly.

Ultrasonic power testers are available in portable and online monitoring models to suit various application needs.

Ultrasonic sound intensity meters (or sound level meters) utilize the piezoelectric effect of piezoelectric ceramics. This means that when a force is applied to the ceramic, it converts that force into an electrical signal. Under the same conditions, a stronger force produces a higher voltage. If the force changes periodically, the piezoelectric ceramic will output an AC voltage signal with the same frequency. Due to cavitation and other forms of interference, the actual voltage waveform is a combination of a main wave and multiple secondary waves. Our company’s high-precision ultrasonic frequency (energy) analyzer allows users to view the actual operating waveform and read the sound intensity value directly.

Key features

• One-touch automatic measurement with automatic display of sound intensity and waveform.
• Digital display of both sound intensity value and frequency.
• A 3.2-inch color LCD screen with 320×240 resolution and LED backlight.
• A built-in 2300mAh lithium battery pack and an external AC power adapter.
• Automatic shutdown after 10 minutes of no signal input.

Frequently Asked Questions

The data always reads zero.

A: When the probe is in the air, the sound intensity meter will immediately show a real-time sound intensity value of 0 W/cm² and will automatically turn off after one minute.

The readings appear to be inaccurate.

A: The sound intensity of ultrasound is a complex concept. It cannot be calculated simply by dividing the total power by the radiation area; it must be measured. Our sound intensity meters are calibrated using a standard sound intensity before leaving the factory, ensuring the measured values are accurate. There is a limit to sound intensity; once a certain threshold is reached in water, adding more transducers or increasing power may not lead to a linear increase in sound intensity, or even any change at all.

High-frequency devices cannot be measured.

A: Our sound intensity meters are designed for standard ultrasonic cleaning machines, covering a primary frequency range of 10-200kHz. Measurements taken outside of this range will be inaccurate. This can be addressed in two ways:

• Inform us of the specific frequency range you need to measure, and we can create a customized display and probe.
• Use an oscilloscope for relative measurement. The probe can be directly connected to the oscilloscope and the sound intensity can be compared by reading the oscilloscope’s time domain signal. This method does not provide an absolute sound intensity value, but allows for a comparison between measurements.

The reading is abnormal; a reading appears even when not in liquid.

A: This issue indicates damage to the display unit and requires return to our company for repair.

The display screen is black with no display.

A: The instrument has a power-saving mode. The display will turn off if the measured sound intensity is 0 W/cm² for one minute. If pressing the ON/OFF button does not restore the display, try replacing the battery. If the display remains off, this indicates the screen is damaged and requires return to our factory for repair.

Readings vary greatly when two devices are used simultaneously.

A: Our ultrasonic equipment is calibrated with a standard sound field before shipment. In ultrasonic cleaning, sound waves reflect off the container walls and water surface, causing the sound intensity to vary throughout the cleaning machine. This creates a standing wave field, where the sound intensity is minimal at nodes and maximal at antinodes.

For example, in a 28kHz cleaning machine, the sound wavelength in water is 5.4cm, with two nodes and two antinodes per wavelength. This means the distance between a node and an antinode is 1.3cm. For a 40kHz machine, this distance is 0.9cm.

Therefore, when using two sound intensity meters, it is essential that they are measuring the same point to compare readings accurately. Given the close proximity of nodes and antinodes, hand-held measurements are prone to error due to unavoidable movement, altering the sound field. Our company recommends using a mechanical clamping method to secure the probe and ensure consistent measurement locations. This controlled environment enables a meaningful comparison between the two devices.

Values vary greatly when tested at different points in the same tank.

A: Ultrasonic cleaning machines generally use wall-mounted transducers attached to the bottom or sides of the tank. The installation process, size specifications, and consistency of these transducers can all contribute to an uneven sound field within the cleaning tank, leading to variations in sound intensity at different points and, thus, different measured values.

How frequently does the instrument need recalibration, and how is it determined?

A: Based on the detection transducer calibration standard, this type of product should be calibrated once per year.

There is unusual noise in the display unit.

A: This may be caused by loose internal components. It is recommended to return the unit for inspection and repair.