Pump Pump suren12564 (Mechanical) (OP) 13 Nov 15 11:59 What will happen when air is entrapped in a centrifugal pump? And if air is entrapped in pipe line loop? RE: Pump LittleInch (Petroleum) 13 Nov 15 13:17 The pump won't work at all or badly until the air is flushed out. Ditto for the piping. You usually need about 1 to 1.5 m/sec velocity to "sweep" out air in pipes. Very vague question so a general response. Do you have a more specific issue / problem? Remember - More details = better answers Also: If you get a response it's polite to respond to it.