Abstract: System for diluting an ultrapure concentrated chemical including: (i) a first tank which contains the chemical in concentrated form having a predetermined purity P, (ii) a supply of ultrapure water of purity at least equal to P, (iii) a second tank for mixing the concentrated chemical with the ultrapure water to obtain a solution of diluted chemical whose purity is at least equal to P, (iv) a structure for adjusting the titre of the solution of diluted, chemical to a desired final concentration.

Abstract: An apparatus for delivering abrasive suspensions includes a reservoir containing an abrasive suspension, a loop for delivering the abrasive suspension to a point of use, the loop being connected to the reservoir, a pumping arrangement for circulating the abrasive suspension in the loop and for ensuring its return into the reservoir, the loop and the reservoir being arranged for recovering the abrasive suspension after circulation in the loop at a recovery point of the reservoir, and a control system for controlling the pumping arrangement so as to maintain a continuous circulation of the suspension.