Acoustic Performance of the BP7: Micropump Sound Emission Explained

Micropumps like the BP7 are compact, efficient, and free of rotating parts. But even without motors, they can still produce audible noise depending on how they are operated. In this article, we explore the acoustic behavior of the BP7 micropump, showing how signal shape, operating frequency, and the working medium impact sound levels.

Especially if your application requires silent operation: Let’s break it down.

How We Measured Sound Emission

To understand how the BP7 sounds in different scenarios, we tested 5 pump units under controlled lab conditions:

Test setup:

• Drive voltage: 250 Vpp
• Frequencies: 100 Hz and 300 Hz
• Signal shapes: Sine, SRS (rectangle-sine), and rectangular
• Media: Air and water
• Distances: Directly next to pump, 30 cm, and 1 meter
• Controller: mp-Labtronix
• Note: All tested pumps showed consistent behavior.

Sound Emission Results

With Air as Working Medium

Signal Shape	Frequency	Next to Pump	30 cm Distance	1 m Distance
Sine	100 Hz / 300 Hz	33.5–35 dB[A]	33.5–35 dB[A]	33.5–35 dB[A]
SRS	100 Hz	50–51 dB[A]	40.5 dB[A]	40 dB[A]
Rectangular	100 Hz	66.6 dB[A]	53.4 dB[A]	52 dB[A]
SRS	300 Hz	65–67 dB[A]	50.5–52 dB[A]	47.5 dB[A]
Rectangular	300 Hz	69.8 dB[A]	54.6 dB[A]	53 dB[A]

With Water as Working Medium

Signal Shape	Frequency	Next to Pump	30 cm Distance	1 m Distance
Sine	100 Hz	33.5–35 dB[A]	33.5–35 dB[A]	33.5–35 dB[A]
SRS	100 Hz	38.5 dB[A]	33.5–35 dB[A]	33.5–35 dB[A]
Rectangular	100 Hz	39.2 dB[A]	36.6 dB[A]	35.6 dB[A]
Sine	300 Hz	38.8 dB[A]	35.4 dB[A]	33.5–35 dB[A]
SRS	300 Hz	43.8 dB[A]	37 dB[A]	35 dB[A]
Rectangular	300 Hz	43.8 dB[A]	37.8 dB[A]	35.4 dB[A]

Key Takeaways

• Sine waves with water are the quietest option, staying around or below normal room noise, even directly at the pump.
• Rectangular signals create the most noise, due to sharp edges in the waveform.
• Water dampens sound significantly better than air. The fluid acts as a vibration absorber.
• Distance matters: At 1 meter, most setups stay below 40 dB[A].

Design Recommendations for Low-Noise Applications

• Choose sine or SRS waveforms for minimal acoustic output
• Prefer water over air where possible – the pump sounds quieter with liquids
• Reduce voltage or frequency if max flow isn’t required
• Use damping housings in wearable or mobile devices
• Closed-loop setups help maintain performance while allowing more flexibility in tuning for acoustic behavior

Summary

The BP7 micropump enables highly customizable operation and that includes managing how it sounds. By tuning drive signals, voltage, and fluid type, sound emissions can be reduced significantly. For noise-sensitive environments like medical devices or lab automation, these optimizations can make a real difference.