A hydrocyclone ( 1 ) for separating a liquid mixture into a heavy fraction and a light fraction, comprising a housing ( 2 ) forming an elongated separation chamber ( 3 ) having a circumferential wall ( 4 ), a base end ( 5 ), an apex end ( 6 ), means ( 10 ) for supplying the liquid mixture to the separation chamber ( 3 ) via the at least one inlet member ( 7 ), so that during operation a liquid stream is generated as a helical vortex ( 11 ) about a centre axis ( 12 ), at least one path ( 13 ) in the circumferential wall ( 4 ) at least over a portion of the separation chamber ( 3 ), and at least one means for creating turbulence, which comprises at least one step ( 14 ) in the path ( 13 ) of the circumferential wall ( 4 ) showing an increase of the radius of the separation chamber ( 3 ), wherein the at least one step ( 14 ) having an angle (α) relative the centre axis ( 12 ).
1. A hydrocyclone for separating a liquid mixture into a heavy fraction and a light fraction, comprising: a housing forming an elongated separation chamber having a circumferential wall, a base end, an apex end, at least one inlet member for supplying a liquid mixture into the separation chamber, at least one of the inlet members positioned at the base end, a first outlet member for discharging separated light fraction from the separation chamber at the base end, a second outlet member for discharging separated heavy fraction from the separation chamber at the apex end, means for supplying the liquid mixture to the separation chamber via the at least one inlet member, so that during operation a liquid stream is generated as a helical vortex about a centre axis in the separation chamber, said helical vortex extending from the base end to the apex end, at least one path in the circumferential wall at least over a portion of the separation chamber, and at least one means for creating turbulence, which comprises at least one step in the path of the circumferential wall showing an increase of the radius of the separation chamber, wherein the at least one step has an angle (α) relative the centre axis.
2. A hydrocyclone according to claim 1 , wherein the at least one step induces a pressure drop and a secondary vortex having a rotational axis, the angle relative the centre axis being about the same as the angle (α) for the step or increased.
3. A hydrocyclone according to claim 1 , wherein a passage is formed having about the same radius between two subsequent steps towards the apex end.
4. A hydrocyclone according to claim 1 , wherein a first and a second end of the step is rounded to smoothly connect to the subsequent paths in the circumferential wall.
5. A hydrocyclone according to claim 1 , wherein the path of the circumferential wall has a helical shape.
6. A hydrocyclone according to claim 5 , wherein the helical path is asymmetric so that one side of the circumferential wall is smooth and the opposite side has increased path depth compared to a symmetric helical path.
7. A hydrocyclone according to claim 1 , wherein the path of the circumferential wall is in the form of asymmetrically arranged cylinders, decreasing in radius towards the apex end, where one side of the circumferential wall is smooth and the opposite side has increased path depth compared to symmetrically arranged cylinders.
8. A hydrocyclone according to claim 1 , wherein each revolution of the path of the circumferential wall comprises a step.
9. A hydrocyclone according to claim 1 , wherein the angle (α) of the step relative the centre axis is between 2 and 70 degrees.
10. A hydrocyclone according to claim 9 , wherein the angle (α) of the step relative the centre axis is between 5 and 45 degrees.