EP0815944A2

EP0815944A2 - Cyclone separator

Info

Publication number: EP0815944A2
Application number: EP97304879A
Authority: EP
Inventors: Peter Gould; Martin Dennis Grewer
Original assignee: Kvaerner Process Systems AS
Current assignee: Fjords Processing AS
Priority date: 1996-07-06
Filing date: 1997-07-03
Publication date: 1998-01-07
Also published as: NO973130D0; CA2209954A1; GB9614258D0; NO973130L; EP0815944A3

Abstract

A cyclone (2) comprises a first and second chambers (14, 16) separated by a wall (18) having an aperture (20). Frusto-conical directing means (34) is provided for guiding a fluid within the first chamber (14) towards the aperture (20).

Description

This invention relates to a cyclone separator of the type used to separate a mixture comprising a fluid of a first density and fluid of a second density, for example, oil and water.

The separation of a mixture of fluids, for example oil and water, into its individual constituents is achieved in a known type of hydrocyclone by the generation of a vortex in the mixture within the hydrocyclone effecting centrifugal separation of the mixture so as to produce an "oil-core". The separated oil and water are collected individually at respective output ports. However, it has been found that transfer of the oil from the oil-core to the oil output port may be less than optimum, especially when the hydrocyclone is operating at low flow/pressure with consequent reduction in centrifugal forces in the mixture.

According to a first aspect of the present invention, there is provided a cyclone separator comprising a first chamber within which a separation vortex is generated in use, said chamber having an end wall, an aperture in said end wall, and, directing means tapering inwardly from said chamber towards said aperture for guiding a core of said vortex within the first chamber towards the aperture.

Desirably said wall defines said directing means.

Conveniently said directing means substantially surrounds said aperture.

Preferably said directing means is a frustum of a cone defined by said wall with said aperture at its apical region.

The invention will now be described, in more detail, with reference to the accompanying drawings, in which:

Figure 1 shows a cross-sectional view of a hydrocyclone according to an embodiment of the present invention; and

Figure 2 shows a part of Figure 1 in more detail.

The hydrocyclone 2 of Figure 1 comprises a tapering tube element 4 having a water output port 10 at its narrower end and an opposite end portion 6 having one or more, desirably tangential, input ports 8, and an oil output port 12.

Referring to Figure 2, the end portion 6 comprises a first chamber 14 defined in part by the tapering outer wall 26 of the tapering element 4. The mixture inlet ports 8 are disposed in the wall 26 of the chamber 14 so as to be in fluid communication therewith and the portion 6 further includes a second chamber 16, and a dividing wall 18 separating the first and

second chambers

14, 16. The dividing wall 18 has an aperture 20 located centrally therein and providing access from the chamber 14 to the chamber 16, the chamber 16 including the oil outlet port 12.

The dividing wall 18 has a main, annular portion 28 of frusto-conical shape which extends into the chamber 14 and tapers inwardly, having a generatrix inclined at an angle to a plane P which is perpendicular to a central axis A of the hydrocyclone 2. The central portion 34 of the dividing wall 18 is also of a frusto-conical shape which tapers inwardly, but the portion 34 extends in the opposite direction to the portion 28, towards the second chamber 16, and has the aperture 20 disposed at its apical region 36.

In use, an oil-water mixture is introduced into the hydrocyclone 2 via the inlet ports 8 so that a vortex is created within the first chamber 14 and the tube element 4.

The individual constituents, i.e. the oil and the water are separated, the water component residing at the periphery of the vortex and the oil component residing at the core of the vortex (known as an "oil-core"). The pressure balance within the hydrocyclone creates a back pressure providing the oil-core with an axial velocity towards the dividing wall 18. The inwardly tapering portion 34 of the wall 18 directs the peripheral portion of the oil-core towards the aperture 20 thereby minimising loss of transfer of the oil core from the first chamber to the oil output port 12 in low inlet flow and pressure operating conditions.

The oil channelled from the oil-core towards the aperture 20 by the portion 34 passes through the aperture 20 into the second chamber 16 and leaves the hydrocyclone 2 via the oil output port 12.

The water at the periphery of the vortex travels along the tube element 4 towards the water output port 10.

Although the above examples have been described in the context of the dividing wall 18 having the main portion 28 of frusto-conical shape, it is not intended that the invention be limited to such a configuration, other configurations being possible. For example, the main portion 28 can be formed so as to have a flat or bulged shape. Similarly, the portion 34 may have a shape other than a frusto-conical configuration provided that it possesses a shape having an opening wider than the widest expected "core" in use and capable of collecting and guiding fluid inwardly towards the aperture 20, for example a curved, dished shape.

Additionally, although the above examples have been described in the context of an oil-water mixture, it is not intended that the invention be limited to such a mixture and the use of other mixtures is envisaged, for example water/gas or powder/water. In this respect, it is not intended that the definition of the term fluid be limited to liquids and gasses alone, but instead to include powders or solids suspended in liquids or gases.

Claims

A cyclone separator comprising a first chamber (14) within which a separation vortex is generated in use, said chamber having an end wall (18), an aperture (20) in said end wall, and the cyclone being characterised by directing means (34) tapering inwardly from said chamber (14) towards said aperture (20) for guiding a core of said vortex within the first chamber towards the aperture.
A cyclone separator as claimed in Claim 1, characterised in that said wall (18) defines said directing means (34).
A cyclone separator as claimed in Claim 1 or claim 2, characterised in that said directing means (34) substantially surrounds said aperture (20).
A cyclone separator as claimed in any one of Claims 1 to 3, characterised in that said directing means (34) is a frustum of a cone defined by said wall (18) with said aperture (20) at its apical region.