Patent ID: 6953423

Claim:
Control equipment for a centrifugal separator for separating a light liquid having a relatively low density and a heavy liquid having a relatively high density from a mixture containing these two liquids, the centrifugal separator including: a rotor rotatable around a rotational axis and forming an inlet for said mixture, a separating chamber communicating with said inlet and having a radially inner part and a radially outer part, which parts during a separating operation contain separated light liquid and separated heavy liquid, respectively, and a space communicating with said radially outer part of the separating chamber such that during a separating operation it will contain separated heavy liquid but not separated light liquid, and control equipment including a supply device for supplying a control liquid to the rotor, said control liquid having a higher density than said light liquid, said supply device having a pressure source for supplying pressured control liquid and a supply conduit having one end connected to the pressure source for receiving pressurized control liquid and another end connected to a liquid transferring member for introducing pressurized control liquid into the rotor and means for sensing changes in liquid pressure in said space of the rotor, the supply device being arranged to supply control liquid to the rotor in response to a reduction of the liquid pressure in the space from a predetermined value but only in an amount per unit time required to get the predetermined value of the liquid pressure resumed, and thereby to avoid an interface layer formed in the separating chamber between the separated light liquid and the separated heavy liquid or control liquid moving radially outwardly from a predetermined radial supply level, a discharge device for discharging at least one of the separated heavy liquid and the control liquid from said space in the rotor, said discharge device having a discharge conduit and being arranged, when the rotor is charged with an excess amount of heavy liquid, to discharge at least one of the separated heavy liquid and control liquid from the rotor through said discharge conduit in an amount per unit time that is required to avoid said interface layer moving radially inwardly from a predetermined radial discharge level, and the discharge device being constructed for discharge of liquid from said space in the rotor a different way than through said supply device.