Definition - What does Desander mean?
A Desander is a hydroclone that is used to remove sand and silt from drilling fluids in a drilling rig. Hydroclones operate on the basis of centrifugal force such that the mud with smaller particles is returned to the active system while the larger particles are discarded. The usual size of a desander is 6 inches and above, however, the most common size is 10 inches.
Petropedia explains Desander
A desander just like a desilter is a part of solid control equipment on drilling facilities. It is a hydroclone whose primary function is to remove sand particles which have a grain size of 50 to 70 microns. The installation position of desander is on the top of the mud tank following the shale shaker and the degasser, but before desilter. All solids that are not removed by a shale shaker are removed by the desander. Desanders do not have any moving parts hence the removal of sand and silt from the drilling fluid is done by the centrifugal force on the desander.