Patent ID: 6976948
Filing Date: 2005-12-20
Classification: B04B

Abstract:
1. A method for adjusting an interface formed between a specific light liquid phase and a specific heavier liquid phase to a wanted radial level in a centrifugal separator, which includes: a rotor having a rotation axis about which the rotor spins, an inlet chamber, in which a conduit for the supply of a mixture of the specific light phase and the specific heavier liquid phase, which is to be separated, opens, a separation chamber communicating with the inlet chamber, an outlet device for discharging the specific light liquid phase separated during operation comprising, the outlet devise an outlet passage connected to a radial inner portion of the separation chamber, and an outlet device for discharging the specific heavier liquid phase separated during operation, this outlet device comprising an outlet channel formed in the rotor extending radially and having an inlet opening at its radial outer end located at a certain radial level in a radial outer portion of the separation chamber, the outlet device at its radial inner end opening into an outlet chamber surrounding the rotation axis, in which the specific heavier liquid phase forms a rotating liquid body having a radially inwardly turned free liquid surface, the radial position of which during operation takes a position at a level in balance with the pressure prevailing in the separation chamber at the inlet opening, and in which a discharge device is arranged, which is non-rotatable with the rotor and has at least one internal discharge channel, which extends radially and at its radial outer end has an inlet opening and at its radial inner end is connected to an outlet, at least a radial outer part of the discharge device, in which the inlet opening is located, being movable in a way such that the inlet opening can be positioned in a different radial location in the outlet chamber, the centrifugal separator further comprising means for the supply of a predetermined volume of the specific heavier liquid phase to the separation chamber, a first indicating means for indicating that the separation chamber during operation is filled up to a certain wanted level, means for keeping the separation chamber filled up to this radial level, and a second indicating means for indicating the radial position of the free liquid surface in the outlet chamber for the specific heavier liquid phase, the method including the steps of causing the specific heavier liquid phase to be pressed radially inwardly in the outlet channel and further into the outlet chamber, thereby forming a rotating liquid body having a radially inwardly free liquid surface displaced inwardly until the separation chamber has been filled; sensing the radial position of the free liquid surface via the first indication means; adjusting the position of the radial outer part of the discharge device so that the inlet opening is moved toward the free liquid surface is the outlet chamber, this movement continuing until the inlet opening reaches the liquid surface and the specific heavier liquid phase in the outlet chamber is discharged through the inlet opening and the discharge channel; sensing that the heavier liquid phase is being discharged through the inlet opening via the second indicating means; preventing the inlet opening from moving by means of a force transferring element acting on the outer moveable portion of the discharge device; and allowing the centrifuge to operate so that separation takes place and the heavier liquid phase and the specific lighter liquid phase are each discharged, through one of the outlet devices while maintaining the desired radial level for the free liquid surface in the outlet chamber.