Application:

The food industry, oil and gas industry, power plants and construction facilities, and air conditioning

Acoustic Closure is used when it is not possible to control noise at the source or in the flow path due to technical, financial, or operational problems. The acoustic cover is placed on the device or equipment and its dimensions are as small as possible and the size of the device. The acoustic enclosure is designed to open easily if necessary during repairs or inspections and does not interfere with the operation of the device. Acoustic coatings are called Acoustic Cladding, Sound Lag, Acoustic Lagging, and Sound Proof.

The acoustic cover can be opened according to the needs of the employer so that if needed, the user can open the acoustic cover and install it again after the visit. The material of the acoustic coating is selected according to the environmental and working conditions according to the standards.

Ejector's Closure

In the figure below, a sample of one of the company’s noise pollution control projects is shown. The project involved the implementation of an acoustic enclosure at the Golshad Food Industries plant in Mashhad. The enclosure was designed and installed to mitigate noise emissions generated by a steam ejector.

Steam ejectors are widely used across various industrial sectors, including the food processing industry. These devices are commonly employed to create suction and vacuum conditions in adjacent vessels for applications such as concentration, evaporation, and material transfer.

Within the ejector, the incoming steam accelerates through a converging-diverging conical nozzle and reaches sonic velocity. This increase in steam velocity results in a pressure drop at the suction section of the ejector, thereby producing the required vacuum effect. However, the high-velocity steam flow and associated turbulent mixing generate significant broadband noise, which can propagate into the surrounding acoustic field and contribute to elevated sound pressure levels in the plant environment.

The image on the right illustrates the ejector prior to the installation of the acoustic enclosure, while the image on the left shows the system after installation. The enclosure was custom-designed and fabricated to match the exact geometry of the ejector, ensuring effective noise attenuation while maintaining operational accessibility and thermal considerations.

The sound pressure levels before and after the installation of the acoustic enclosure on the ejector were measured, and the results are presented in the chart below. The measurements indicate that the maximum noise level of the ejector occurs at a frequency of 4000 Hz, which is referred to as the critical frequency. This frequency served as the primary basis for the acoustic design.

The bar chart on the right shows that the overall (A-weighted) sound pressure level across all frequencies was reduced from 102 dB(A) to 82 dB(A), representing a total noise reduction of 20 dB. The acoustic enclosure demonstrated its greatest effectiveness at the critical frequency, where the highest level of noise attenuation was achieved.