Design noise enclosures

Acoustic control identification of sources of noise enclosure of noise muffling re-design of noise producing parts. 

In addition, they are usually constructed without isolation valves on the fuel supply lines. As a result the final connection in the pipework cannot be leak-tested. In practice, it is tested as far as possible at the manufacturer s works but often not leak-tested on-site. Reference 32 reviews the fuel leaks that have occurred, including a major explosion at a CCGT plant in England in 1996 due to the explosion of a leak of naphtha from a pipe joint. One man was seriously injured, and a 600-m chamber was lifted off its foundations. The reference also reviews the precautions that should be taken. They include. selecting a site where noise reduction is not required or can be achieved w ithout enclosure. If enclosure is essential, then a high ventilation rate is needed it is often designed to keep the turbine cool and is far too low to disperse gas leaks. Care must be taken to avoid stagnant pockets. 

In such cases, enclosed flares may provide one solution. Enclosed flares are designed to completely hide a flare flame in order to reduce noise and thermal radiation levels. The design of these flare systems typically consist of an insulated enclosure with a wind fence around the perimeter as shown in the photograph in Figure 8.28. These types of flares can substantially reduce noise emissions as compared to open elevated flares. 

There are several ways to modify the path sound waves may take. There are enclosures, room absorption, barriers or shields, absorption along a transmission path, and mufflers. Not all methods are available to reduce noise for each design problem. 

Machinery enclosures Walls of acoustic enclosures should consist of heavy but flexible panels lined internally with sound-absorbing material. Adequate ventilation, demountability of the enclosure for repairs, and arrangements for operating and/or observing the machine to be provided. If hot gas fans are acoustically enclosed, the surface of the fan casing should additionally be heat-insulated. For information on design and performance of enclosures for noise control see VDI2711. 

The outer frame is a simple fabricated enclosure that supports either the air inlets and silencers if the unit is open-ventilated (Fig. 6.33) or the roof and cooler enclosure if the unit is totally enclosed water-to-air-cooled. The outer frame further acts as an air guide to complete the ventilation paths, and as a sonndproof enclosure to keep noise levels low. Since the rotor is pedestal mounted, the end shields are very simple structures. As with the inner frame, the outer frame is designed to be free of resonances in the range of operating frequencies. 

With respect to noise control in mining, enclosed production processes and workstations, as mentioned above, are common. When enclosing a production process such as a crusher or a screen tower, noise levels in the surroimding plant areas are reduced however, levels inside the enclosure can be significantly increased. The design of an enclosed production process needs to consider minimizing the need for employees to enter the enclosure. Use of plastic or rubber screens is an effective method for reducing overall production noise levels. 

Design controls that could be used, such as isolation, enclosure, ventilation, noise, or radiation barriers. 

Specially designed, so-called warpless baseplates prevented pressure-generated tilt noise fi om contaminating horizontal components. The electronics are housed in a separate enclosure which is not sealed and which can require regular replacement of desiccant to avoid anomalous response characteristics (Hutt and Ringler 2011). 

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