Why surging is not happening in centrifugal pump & reciprocating compressor?

Surge can be defined as the capacity below 55 to 70%, which the centrifugal compressor performance becomes unstable. When surging occurs, the high-pressure gas at the discharge of the machine flows back through the compressor in a complete reversal of the normal direction of flow causing the collapse of pressure producing ability will repeat and cycle through the same sequence. Surging controlled by;

Increase the flow from process to compressor suction

By-pass some discharge through coolers, back to suction of the unit

Decrease the pressure ratio.

Please get yourself clarified.

Surging do happen in Centrifugal pump, but the chance of surging in gear pumps is very less. 

Surging can be occur in pumps...but it does not have dangerous effects like in compressor. surging in pumps can be controlled by NPSH (net positive suction head). SURGING IN Compressors refers to cavitation.