Saturday, November 14, 2009

Compressed Air Receivers!

Sizing and Location of Air Receivers!
Air receivers are air tanks, placed in the compressed air system to serve as air supply buffers or demand surge tanks. Proper sizing of these tanks and correct location means a lot, depending upon the type of loads at hand, and what kinds of applications are being done at the load side.

Normally, an air receiver tank is placed to take care of demand fluctuations, and to take care for a 30second demand, time constant in the system. This will enable the air compressors to react to increases in demands, within thirty seconds, and at same time prevent a too large a drop in the overall system pressure. The system pressure, however, is not entirely dependent on the sizing of the compressors, and its reaction time. It is also dependent on the pipe sizing and the load demand. Assuming, the pipe sizing and load demand were properly designed, then the air receiver size will be more likely to be functioning as a buffer stock storage, and allowance for the compressor reaction time (usually within 30 seconds). To quantify this, one should calculate the capacity of the compressor to deliver vis-à-vis the load demand fluctuation in 30 seconds time. This can easily be determined by the general gas laws principles, and system calculations using quasi-static conditions, as your assumptions.

What about the locations of the air receivers? Normally, air receivers that are located immediately after the compressors, and situated before the refrigerated air dryers or dessicant dryers, will have the extra benefit of cooling the compressed air at the receiver, and serve as better collection tanks for moisture due to saturation. In system designs like these, the work load for the air dryers is lesser. The air dryers, however that have frequently varying loads in this design case, may also render the air quality to vary too much in certain installations. If the air demand fluctuations are too frequent, the high possibility of an undesirable air quality is present, especially if the air dryer sizing have not been given enough capacity allowance. Even then, the former arrangement, have still been proven to have reduced the energy consumption of the air dryer better, compared to the latter old conventional design of having air receivers after the air dryers. Author:http://www.linkedin.com/in/sannysuerte

No comments:

Post a Comment