a constant flow rate input fluid of mixed gas , oil , water and suspended solids separates into its phases by centrifuging in a chamber of a multiple phase separator . clean oil draws off through a mouth of a pitot tube tap which extends into the chamber . solids leave the chamber through radially perimetric orifices . water leaves the chamber through a radial passage opening into the chamber radially inward of the orifices and outward of the mouth of the pitot tube . gas leaves the chamber through an annular tap radially inside the mouth of the pitot tube . an overflow oil stream leaves through this annulus and keeps separate from the gas by gravity . the quantity of water in the chamber determines the radial positions of the lighter constituents of oil and gas so that each tap for these phases draws only the proper phase . insufficient water in the chamber reduces the water flow rate from the separator , which generates a signal that recirculates water from a reservoir into the separator to increase the quantity of water there . too much water increases the water flow rate from the separator . too little oil results in stoppage of the overflow oil stream . when the latter flow stops , oil flow from the pitot tube stops to allow the input fluid to increase the percentage of oil in the chamber . the overflow annulus is sufficiently capacious to drain excess oil without further phase adjustment .