Acoustic cleaning is the use of low frequency, high-energy sound waves to resonate and dislodge particulate deposits from structural surfaces. Sound is transmitted via the movement of particles in a medium, such as air. Cleaning energy is transferred via a series of compression and tension cycles that create movement in the air to fluidize dust particles that have collected on various surfaces. The acoustic disturbance can be represented as a wave, with the x-axis representing time, and the y-axis the displacement of a given particle in the medium from its rest position. Once the particulate has been displaced, it is removed by gravity and/or gas flow.

The sound we hear is described by its frequency. Frequency is measured in hertz (Hz), or cycles per second. The general range of hearing humans can detect is between 20 Hz and 20 kHz. The fundamental measurement of loudness is the "BEL" named for Alexander Graham Bell. The decibel (dB) is one-tenth of a BEL. The decibel is, technically, a logarithmic scale of acoustic pressure. In the measurement of sound, the focus is on amplitude of the acoustic pressure, measured in Pascals (Pa) and/or dB. An increase of 10 dB represents a 10-fold increase in sound pressure.

No. Acoustic energy emitted by Powerwave acoustic cleaners is at frequencies greater than 60 Hz. This is well above the natural (resonant) frequency of most structures. Since 1983, there have been thousands of Powerwave acoustic cleaners installed worldwide, without a single case of structural damage to equipment.

The selection of an acoustic cleaner for any given application is affected by many variables. These include the amount of area to be cleaned, the temperature of the process, the process gas conditions,and the type of particulate being cleaned are just some of the criteria to be considered. Placement of the acoustic cleaner is also important to ensure buildup areas are properly addressed. For best results, a full evaluation of the process and application must be made prior to purchasing and installing the acoustic cleaners. Qualified and experienced members of the BHA's Powerwave Acoustic Product Team are available to evaluate your system and recommend the best solution.

The ambient noise increase during the sounding of an acoustic cleaner will vary greatly by application. For example, the ambient noise of an acoustic cleaner being sounded in a thin wall storage bin will be louder than an acoustic cleaner being sounded in a well-insulated boiler. Typically, the intermittent operation of the acoustic cleaner will not increase the ambient noise enough to qualify the area as a hearing protection area. This is based on OSHA Permissible Noise Limits.

Any application that is suffering from buildup and/or flow problems caused by dry particulate deposits will benefit from acoustic cleaning. Acoustic cleaners also require gravity and/or gas flow to sweep away the particulate that has been resonated or fluidized by the acoustic energy.

Powerwave acoustic cleaners require no regular maintenance. Once installed, the unit will operate unattended. There is only one (1) moving part (diaphragm), which has a life expectancy of 2 to 5 years depending on the sounding requirements of the acoustic cleaner. In most applications, the diaphragm can be replaced while the equipment is on line.

The air requirements for sounding a Powerwave acoustic cleaner will vary slightly from model to model. The air pressure requirements will range from 50 to 90 PSI. The airflow rate will vary from 60 to 80 SCFM. It is important to note that the acoustic cleaners are not operated continuously. They are typically operated for several seconds every few minutes. Based on an operating cycle of ten seconds every ten minutes, an acoustic cleaner will consume less than two SCF per minute.