Core technology
Sonic horn
Also known as sonic horns, sonic cleaning horn, industrial sonic horn.
A sonic horn is a pneumatically-driven sound emitter that produces high-intensity, low-frequency sound waves — typically between 60 and 400 Hz at sound pressure levels of 140 to 180 dB — used to dislodge particulate fouling from inside industrial process equipment. Sonic horns are the most common form of acoustic cleaner and the default specification for cleaning ESPs, baghouses, SCR catalysts, boiler heat-transfer surfaces and hoppers and silos.
How a sonic horn works
Compressed plant air admitted through a solenoid valve drives a metal diaphragm — typically titanium or 316 stainless — into resonant oscillation at the horn's fundamental frequency. The oscillating pressure field is amplified by an exponential bell horn and projected into the vessel as a near-spherical sound wave. Particulate already deposited on internal surfaces receives an oscillating acceleration that overcomes adhesion; loosened material is then carried out with the gas flow before it can sinter, bridge or bond. Because the cleaning is acoustic and non-contact, the horn can fire while the plant is online without tube erosion, refractory damage or thermal shock.
Key parameters
| Parameter | Typical range |
|---|---|
| Fundamental frequency | 60–400 Hz |
| Sound pressure level | 140–180 dB |
| Compressed-air consumption | 8–14 Nm³/min at 4–7 bar |
| Operating temperature (with appropriate materials) | −40 °C to +500 °C |
| Firing cycle | 5–15 s burst, repeated every 3–15 minutes |
| Mass | 15–60 kg depending on horn size |
Frequency selection
Lower frequencies (60–125 Hz) project longer wavelengths and penetrate further into large open vessels — preheater cyclones, recovery-boiler superheaters, large ESP fields, silos. Higher frequencies (230–400 Hz) carry more energy per unit volume and suit finer dust loads in fabric-filter compartments, catalyst layers and smaller hopper geometries. See low-frequency acoustic cleaner and high-frequency acoustic cleaner.
Sonic horn vs steam sootblower
Sonic horns are increasingly specified alongside or in place of steam sootblowers because they consume no boiler-grade steam, cause no tube erosion, require almost no moving parts and can fire every few minutes without operator intervention. They are less effective on hard, fused slag than retractable steam lances, so on furnace waterwalls and high-temperature superheaters they typically complement rather than replace mechanical cleaning.
Related terms
Related terms
- Acoustic cleanerAn acoustic cleaner is any device that uses high-intensity sound waves to dislodge particulate fouling from inside industrial process equipment such as boilers, ESPs, baghouses and silos.
- Acoustic cleaning systemAn acoustic cleaning system is the engineered assembly of sonic horns, compressed-air supply, solenoid valves and cycle controllers that delivers programmed acoustic cleaning to industrial process equipment.
- Sonic sootblowerA sonic sootblower is a sonic horn used specifically on boiler heat-transfer surfaces. It uses low-frequency sound instead of high-pressure steam, eliminating tube erosion and steam consumption.
- Bell hornA bell horn is the conical or exponential flare that amplifies and projects sound from an industrial sonic horn's driver into the vessel being cleaned.
- Diaphragm hornA diaphragm horn is a sonic horn whose sound is generated by a vibrating titanium or stainless-steel diaphragm driven by pulsed compressed air. The dominant form-factor for low-frequency industrial cleaning.
- Low-frequency acoustic cleanerLow-frequency acoustic cleaners operate at 60–250 Hz. The long wavelength penetrates deep into large open vessels such as ESPs, recovery boilers and cement preheater cyclones.