Gas Mover Operating Parameters

The basic parameters to consider when purchasing, operating, or maintaining any gas mover are  

Gas movers have three other operating parameters that affect their safe operation heat of compression, surge, and stonewaU. 

Surge is a phenomenon that occurs at conditions of low flow in centrifugal gas movers. All manufacturers include in their equipment specification a minimum allowable flow. At low flow, the dynamics of the piping system and the operating curve of the gas mover can be out of balance, causing pressure pulses and equipment vibrations, known as surge. The vibration is translated to the thrust system and will ultimately destroy the equipment if surging is not stopped. 

or incipient surge, produces a noticeable drop in flowrate, while surge does not. This drop occurs when the gas stream actually separates fix m the impeller. Centrifugal fans and axial-flow fans arc susceptible to stall at flow rates just below that which produces tire peak discharge pressure. Stall there- 

---