Teach me plz................a....b....o...u....t.......

I think your are refering to air "purging". When the pump is being started, it is necessary to remove all the undisslved gases/ vapours formthe casing. trapped air in the pumo systems decreases the available head of the pump causing the overall plant efficciency to fall low. To avoid this, at the start up, pump i spurged with water or other fluid which will push the gases out. Thi sis my understanding. Kindly correct me if wrong.

Sparging uses compressed gases to perform mechanical mixing. In the case of a sump, it would be my assumption that that it would be used to re-suspend in solids that had precipitated out of solution and had been deposited on the sump floor. Such sparging, performed just prior to pumping the sump, would minimize the build up of solids in the sump. I am aware of no formal calculations for the number and size of holes to be used or the volume (or, more properly, volumetric flow rate) of air to be used, although I'd wager one of the knowledgeable posters who frequent this forum will be able to help you out in that regard. What I do know, is that for sparging to be effective, it must allow for complete coverage, I.E. no "dead spots". This is usually accomplished by a ring header for small surface areas, but may require additional headers for larger surface areas. I hope this helps.