AU2008263787B2

AU2008263787B2 - Cyclone separator and method for separating matter from a gas flow

Info

Publication number: AU2008263787B2
Application number: AU2008263787A
Authority: AU
Inventors: Rami Aaltonen; Petri Norri; Juha Tanttari
Original assignee: Metso Paper Oy
Current assignee: Valmet Technologies Oy
Priority date: 2007-06-11
Filing date: 2008-06-11
Publication date: 2011-02-10
Anticipated expiration: 2028-06-11
Also published as: FIU20070247U0; ES2487506T3; WO2008152203A1; CN101678369A; JP4922451B2; EP2167236A1; FI7743U1; EP2167236B1; AU2008263787A1; JP2010528830A; CN101678369B

Description

CYCLONE SEPARATOR AND A METHOD FOR SEPARATING MATERIAL FROM A GAS FLOW TECHNICAL FIELD OF THE INVENTION 5 The invention relates to a cyclone separator and methods employing cyclone separators. BACKGROUND Cyclone separators are needed in several industrial processes in which impurities, 10 such as water droplets, are separated from a gaseous substance. The cyclone separator can be arranged in the processes also before the silencer for maintaining the sound-absorption capacity. For example, registered utility model F12242 describes a cyclone separator for 15 separating particles, for example, water droplets, spray and other similar impurities, from a gas flow. The separator comprises a feed channel for feeding the gas to be purified into the separator chamber and a separator chamber for separating the particles from the gas flow, the diameter of which separator chamber is greater than that of the feed channel. The cyclone separator also comprises a gas discharge 20 channel and a particle discharge channel. The cyclone separator also has a vane group placed in the feed channel for bringing the gas flow into a swirling motion. A vane group is also placed in the gas discharge channel in order to straighten the gas flow which has been brought into a swirling motion. 25 One problem with known cyclone separators is that, at the central axis of the inlet connection, the distance travelled by the particles entering the separator chamber to the wall of the separator chamber is longer than that travelled by the particles that are already at the inlet connection close to the wall. For this reason, there is no time for some of the particles entering at the central axis to hit the wall of the separator 30 chamber, but they pass through the cyclone separator without any separation taking place. Separation may be improved by increasing the angle of the vane, in which case a larger proportion of the particles hits the wall of the separator and is separated from the gas flow. However, the problem with the increased angle of the vane is a higher pressure drop. 25047491 (GHMatters) 4/01111 -2 SUMMARY OF THE INVENTION It would be advantageous to provide a solution that improves the separation of the material to be separated in the cyclone separator. 5 It would be advantageous to reduce or even prevent the passing of the gas and the material to be separated contained therein through the cyclone separator at the central axis of the separator. 10 It would be advantageous to reduce the pressure drop in relation to the separation efficiency of the separator. In accordance with the invention, there is provided a cyclone separator for separating the material to be separated from a gas flow, which cyclone separator comprises: 15 a separator chamber, an inlet connection for feeding gas into the separator chamber, and a discharge connection for discharging gas from the separator chamber, which separator chamber, inlet connection and discharge connection have a central axis and a wall, and 20 a separation opening for discharging the separated material from the separator chamber, and at least one guide vane in the inlet connection and/or separator chamber for directing the gas flow towards the wall of the cyclone separator, which guide vane has - a first surface and a longitudinal axis substantially parallel to it, and 25 - a base portion by means of which the guide vane is arranged in conjunction with the central axis of the inlet connection and/or that of the separator chamber, from where the first surface and the longitudinal axis are arranged radially so that they protrude towards the wall of the separator chamber and/or that of the inlet connection, 30 wherein at least a portion of the first surface of the guide vane is arranged, by turning it around its longitudinal axis or in a similar way, at an angle (a) which is 1-90 degrees, preferably 5-70 degrees, very preferably 10-60 degrees in relation to the main direction of the gas flow, whereby the angle (x) of the first surface in relation to the main direction of the gas flow is arranged to be variable at least in the direction 35 substantially perpendicular to the main direction of the gas flow, i.e. in the radial 2504749_1 (GHMatters) 4101/111 -3 direction, in such a way that the angle (cx) is greatest in conjunction with the central axis and decreases on average towards the wall of the cyclone separator. Described herein is a cyclone separator for separating the material to be separated 5 from a gas flow comprises - a separator chamber, - an inlet connection for feeding gas into the separator chamber, and - a discharge connection for discharging gas from the separator chamber, which separator chamber, inlet connection and discharge connection have a 10 central axis and a wall. The cyclone separator also comprises - a separation opening for discharging the separated material from the separator chamber, and 15 - at least one guide vane in the inlet connection and/or separator chamber to direct the gas flow towards the wall of the cyclone separator. The guide vane has - a first surface and a longitudinal axis substantially parallel to it, and 20 - a base portion by means of which the guide vane is arranged in conjunction with the central axis of the inlet connection and/or that of the separator chamber, from where the first surface and the longitudinal axis are arranged radially so that they protrude towards the wall of the separator chamber and/or that of the inlet connection. 25 At least a proportion of the first surface of the guide vane is arranged, by turning it around its longitudinal axis or in a similar way, at an angle which is 1-90 degrees in relation to the main direction of the gas flow, preferably 5-70 degrees, very preferably 10-60 degrees. 30 In accordance with the invention, there is provided a method for separating material from a gas flow in a cyclone separator, whereby gas containing material to be separated is directed via the inlet connection of the cyclone separator to its separator chamber, and at the same time 35 - a base portion by means of which the guide vane is arranged in 25047491 (GHMatlers) 4101/11 - 3A said gas is directed from the central axis of the inlet connection and/or the separator chamber of the cyclone separator towards its wall by means of at least one guide vane arranged in the inlet connection and/or separator chamber, which guide vane has 5 - a first surface and a longitudinal axis substantially parallel to it, and - conjunction with the central axis of the inlet connection and/or - that of the separator chamber, from where the first surface and - the longitudinal axis are arranged radially so that they protrude - towards the wall of the cyclone separator, 10 - the gas from which the material has been separated is discharged from the separator chamber of the cyclone separator through the discharge connection, the separated material is discharged through the separation opening located in the separator chamber of the cyclone separator, wherein 15 said gas is directed towards the wall of the cyclone separator by arranging at least a portion of the first surface of the guide vane, by turning it around its longitudinal axis or in a similar way, at an angle (a) which is 1-90 degrees, preferably 5-70 degrees, very preferably 10-60 degrees in relation to the main direction of the gas flow, and the angle (cc) of the first surface in relation to the main direction of the gas flow is arranged 20 to be variable at least on average in the direction substantially perpendicular to the main direction of the gas flow, i.e. in the radial direction, in such a way that the angle (a) is greatest in conjunction with the central axis and decreases, on average, towards the wall of the cyclone separator. 25 Described herein is a method for separating material from the gas flow in a cyclone separator - gas containing material to be separated is directed via the inlet connection of the cyclone separator to its separator chamber, and at the same time - said gas is directed from the central axis of the inlet connection and/or the 30 separator chamber of the cyclone separator towards its wall by means of at least one guide vane arranged in the inlet connection and/or separator chamber, which guide vane has - a first surface and a longitudinal axis substantially parallel to it, and 35 - a base portion by means of which the guide vane is arranged in 25047491 (GHMatters) 4101/11 - 3B conjunction with the central axis of the inlet connection and/or that of the separator chamber, from where the first surface and the longitudinal axis are arranged radially so that they protrude towards the wall of the cyclone separator, 5 - the gas from which the material has been separated is discharged from the separator chamber of the cyclone separator through the discharge connection, 25047491 (GHMatters) 4101/11 WO 2008/152203 PCT/F12008/050349 4 - the separated material is discharged through the separation opening located in the separator chamber of the cyclone separator, - said gas is directed towards the wall of the cyclone separator by arranging at least a portion of the first surface of the guide vane, by 5 turning it around its longitudinal axis or in a similar way, at an angle (Ua) which is 1-90 degrees, preferably 5-70 degrees, very preferably 10-60 degrees in relation to the main direction of the gas flow. The different embodiments and characteristics of the invention described in this 10 application relate, when applicable, both to the cyclone separator and the method for separating material from a gas flow according to the invention, even if it is not always specifically stated. In a preferred embodiment of the invention, the directing of the gas flow towards 15 the wall of the cyclone separator refers to the wall of the separator chamber in particular, but in certain embodiments the gas flow may also be directed towards the wall of the inlet connection. The fact that the cyclone separator comprises at least one guide vane in the 20 inlet connection and/or separator chamber means that at least one vane may be arranged either in the inlet connection or in the separator chamber or simultaneously in both the inlet connection and the separator chamber, in which case the guide vane extends at least partly from the inlet connection to the separator chamber. Also several guide vanes may have been arranged in the 25 inlet connection and/or separator chamber. Typically, there are 2, 3, 4, 5, 6, 7, 8, 9, 10 guide vanes, more typically 2-12 guide vanes, preferably 4-10 guide vanes. The central axis of the inlet connection, separator chamber and discharge 30 connection may be imaginary, that is the central axis does not need to be a real physical structure. Preferably, the central axes of the inlet connection, separator chamber and discharge connection are analogous and congruent, that is they are parallel and set on the same imaginary line.

WO 2008/152203 PCT/F12008/050349 5 According to one embodiment of the invention, the cyclone separator also comprises at least one straightening vane in the discharge connection for straightening the gas flow to be discharged from the separator chamber. 5 Typically, 2, 3, 4, 5, 6, 7, 8, 9, 10 straightening vanes are arranged in the discharge connection. By arranging straightening vane(s) in the discharge connection, the swirling of the gas being discharged from the separator can be reduced in the discharge channel system after the separator. 10 In a preferable embodiment of the invention, the straightening vane has - a first surface and a longitudinal axis substantially parallel to it, and - a base portion by means of which the straightening vane is arranged in conjunction with the central axis of the discharge connection, from where the first surface and the longitudinal axis are arranged radially so that 15 they protrude towards the wall of the discharge connection. At least a portion of the first surface of the straightening vane is arranged, by turning it around its longitudinal axis or in a similar way, at an angle which is 0 90 degrees in relation to the main direction of the gas flow, preferably 5-70 degrees, very preferably 10-60 degrees. 20 The straightening vane may also be placed completely or partially on the side of the separator chamber, close to the discharge connection. In practice, a straightening vane is defined in this application as a vane that is located in the main direction of the gas flow after the centre line of the separator chamber, in 25 the part that is on the side of the discharge connection of the separator chamber. Correspondingly, a guide vane is defined as a vane that is located in the main direction of the gas flow before the centre line of the separator chamber, in the part that is on the side of the inlet connection of the separator chamber. 30 In this application, a guide vane or straightening vane is also referred to generally as a vane. A vane is typically formed of a planar material, for example of a metal plate, such as steel plate, or a plate-like composite material, such as WO 2008/152203 PCT/F12008/050349 6 glass fibre. The vane comprises a first edge that is arranged to meet the- gas flow and a second edge perpendicular to the first edge. The vane is arranged, at its base portion, in conjunction with the central axis of the cyclone separator and the outer edge of the vane is against the base portion, near or in 5 conjunction with the outer wall of the cyclone separator. It is clear that the angle of the first surface of a vane does not need to be the same for the vanes of the inlet connection and those of the discharge connection, that is the guide vanes and the straightening vanes. 10 In this application, material or particles to be separated refers, for example, to water droplets and impurities contained in them, dust, fibres and/or other solid particles. 15 The first surface of the guide and straightening vanes refers to the surface which the gas flow is mainly intended to hit and the main purpose of which surface is to turn and to direct the gas flow in the direction determined by the said surface. 20 By directing the gas flow towards the wall of the cyclone separator, the aim is to bring the gas flow into a swirling motion in the separator chamber. When the gas swirls near the wall, material to be separated is separated from the gas by centrifugal force. 25 Even though the motion of the gas is turbulent and turbulence is intentionally caused particularly in the separator chamber, the main direction of the gas flow typically refers to the direction in which the gas is intended to travel. This direction is often substantially from the direction of the inlet connection through the separator chamber towards the direction of the discharge connection. In 30 most embodiments of the invention, the main direction of the gas flow is the same as that of the central axis of the separator chamber from the inlet connection towards the discharge connection.

WO 2008/152203 PCT/F12008/050349 7 According to one preferred embodiment of the invention, the cyclone separator according to the invention is used as a droplet separator. The cyclone separator according to the invention is well-suited, for example for removing moisture from the gases of the processing industry, particularly well-suited for removing 5 moisture from discharge gases produced in the paper and pulp industry. Especially preferably a cyclone separator according to the invention can be placed in conjunction with the wet end of a paper machine, for example in conjunction with a wire or a press section. The air to be discharged from the wet end comprises water droplets and moisture, which contains also fibres, filler 10 particles and other impurities. These impurities can easily be separated from the air with the solutions according to the invention. An advantage of the cyclone separators according to the invention is their reliability of operation, i.a. they are not clogged as easily as conventional lamellar separators, and they also are very compact in size, which makes it easier to locate them in 15 conjunction with other processing devices. The separator chamber may, for example, be similar in shape to a circular cylinder, a rectangular prism or the like. Its diameter may, for example, be equal to the diameter of the inlet connection leading to it and/or that of the discharge 20 connection leading from it. Preferably the diameter of the separator chamber is greater than that of the inlet connection and/or the discharge connection. The diameter of the separator chamber is typically 0,3-3 m, more typically 0,5-2,5 m, very typically 0,8-2,2 m. 25 The inlet connection comprises at least edges of the inlet opening, in conjunction with which the gas inlet channel may be arranged. Similarly, the discharge connection comprises at least edges of the discharge opening, in conjunction with which opening the gas discharge channel may be arranged for the gas to be discharged from the separator chamber. An inlet opening may 30 also comprise, in addition to the inlet opening, walls located before the inlet opening, and a discharge opening may comprise walls located after the discharge opening, whereby the inlet connection and/or the discharge connection may be independently of each other for example similar in shape to WO 2008/152203 PCT/F12008/050349 8 a circular cylinder, a rectangular prism or the like. The inlet and/or discharge connections can be arranged as separate from the separator chamber, or they can be integral with the separator chamber. The diameter of an inlet and/or a discharge connection is typically 0,25-2,5 m, more typically 0,4-2 m, very 5 typically 0,6-1,8 m. The diameters of the inlet and discharge connections need not be equal in size, but the diameter of the inlet connection can be larger than the diameter of the discharge connection. The length of the inlet connection can also have a different size as compared to the length of the discharge connection. 10 The total length of the cyclone separator is typically in the direction of its central axis typically 0,6-6 m, more typically 1,0--5,0 m, very typically 1,5-4,5 m. Preferably, there is more than one vane arranged in conjunction with the inlet connection and/or separator chamber and/or discharge connection, for example, 15 2-15 or 4-10. According to one embodiment of the invention, the angle of the first surface of the vane is arranged to be variable. This means that in one first part of the first surface, the angle of the vane is of a certain magnitude in relation to the main 20 direction of the gas flow and in a second part of the first surface the angle of the vane is of some other magnitude, i.e. deviating from the first angle. In an embodiment of the invention the angle of the guide vane typically decreases from the base portion of the vane towards its outer edge. At the same time, the angle of the straightening vane typically increases from the first edge towards 25 its second edge in the main direction of the gas flow. The vane may be arranged at the said angle, for example, by turning, twisting, bending, casting to shape. Preferably, the vane is arranged to have a variable angle by turning or twisting the vane, because it is easy and economical. 30 The variable angle may be formed, for example, by folding a finite number of angles in the first surface or by arranging the first surface to be smoothly variable without any visible folds. In an embodiment of the invention the vane is WO 2008/152203 PCT/F12008/050349 9 arranged to have one or more discontinuities, i.e. folds, in which the angle of the first surface of the vane changes. An embodiment of the invention relates to a method for enhancing the 5 separation of particles in cyclone separator comprising a separation chamber, whereby - gas flow containing particles is lead to the separator chamber through the inlet connection located at its first end, - said gas flow containing particles is directed along the surface of at least 10 one guide vane arranged in the inlet connection or the separator chamber, whereby the gas flow is brought in motion towards the other end of the separator chamber and the particles are directed towards the outer wall of the cyclone separator, - gas flow is lead out from the separator chamber through the discharge 15 connection located at the other end of the cyclone separator, and a particle that meets the surface of the guide vane near the centre portion of the cyclone separator is directed to travel at a greater angle towards the outer wall of the cyclone separator than a particle that meets the guide vane further away from the centre portion of cyclone separator. Preferably, the gas flow is brought 20 into s swirling motion towards the other end of the separator chamber by means of at least one guide vane. According to one embodiment of the invention, the angle of the first surface of the guide vane increases in the main direction of the gas flow, i.e. in the 25 direction perpendicular to the longitudinal axis of the vane. This means that while moving in its main direction, the gas first meets the first part of the first surface of the vane which is at a certain angle in relation to the main direction of the gas flow. While the gas moves along the first surface of the vane in its main direction, mainly in the direction of the central axis of the separator chamber, 30 the angle of the first surface increases either gradually or stepwise, for example, at a fold.

WO 2008/152203 PCT/F12008/050349 10 According to one embodiment of the invention, the angle of the first surface of the straightening vane decreases in the main direction of the gas flow. Typically this refers to the angle of the first surface in relation to a direction that passes directly from the inlet connection to the discharge connection. In such a case, 5 the straightening vane straightens the turbulent gas flow to be discharged from the separator chamber to make the flow to be parallel to the central axis of the discharge connection and/or that of the separator chamber. The angle of the first surface of the straightening vane may preferably also be 10 zero degrees, in which case the first surface of the vane is parallel to the main direction of the gas flow. The entire surface of the vane may be at this same angle or the angle may be variable in such a way that it is zero degrees in one part of the first surface and greater in another part of it. 15 According to one embodiment of the invention, the angle of the first surface of the guide vane in relation to the main direction of the gas flow is arranged to be variable at least on average in the direction substantially perpendicular to the main direction of the gas flow, i.e. in the radial direction, in such a way that the angle is greatest in conjunction with the central axis and decreases on average 20 towards the wall of the cyclone separator. By means of this property, the particles entering the separator chamber in conjunction with the central axis can be directed more forcefully towards the wall than those particles that are already close to the wall when entering the separator chamber. This means that the same surface angle of the vane may cover different proportions of the surface 25 area at the base portion of the vane and at the outer edge of the vane. For example, a larger proportion of the base portion of the vane is preferably at a greater angle than of the outer edge of the vane. The angle of the straightening vane may also be arranged in the same way to be on average variable in the radial direction. 30 According to one embodiment of the invention, the cyclone separator also comprises a first centre element, which is arranged substantially in conjunction with the central axis of the inlet connection and/or that of the separator chamber WO 2008/152203 PCT/F12008/050349 11 to direct the gas flow away from the central axis towards the wall of the cyclone separator. Thus the flow in the central axis of the cyclone separator can be prevented or it can be decreased by using the centre element. The first centre element can be arranged to be conical in shape, such that it expands in the 5 main direction of the gas flow towards the guide vanes. The expanding shape of the centre element directs the gas flow away from the central axis of the cyclone separator towards its outer walls, and thereby enhances the directing of the gas flow. Correspondingly, after the guide vanes, a first centre element can be arranged to be conically tapering, in order to optimize the flow conditions. 10 According to one embodiment of the invention, the cyclone separator also comprises a second centre element, which is arranged substantially in conjunction with the central axis of the discharge connection. One or more straightening vanes may be attached to or otherwise arranged in conjunction 15 with the second centre element of the discharge connection. The shape of the centre element may be arranged as tapering in the main direction of the gas flow. The tapering, for example conical form of the centre element directs the gas flow back into conjunction with the central axis and thus evens out the gas flow in the cross section of its flow. 20 Both the inlet and discharge connections may have centre elements that are separate from each other. The centre element of the inlet connection and/or that of the discharge connection may also form a unified single piece with a centre element possibly arranged in the separator chamber and/or with each other. In 25 this case, one unified centre element extends from the inlet connection through the separator chamber along its central line up to the discharge connection. According to one embodiment of the invention, the centre element is cylindrical at least in conjunction with the central axis of the separator chamber. The 30 cylindrical centre element makes it possible to prevent gas from entering into conjunction with the central axis of the separator chamber and thus to force the gas towards the walls of the separator chamber. The cylindrical centre element may be tubular, for example.

WO 2008/152203 PCT/F12008/050349 12 According to one embodiment of the invention, at least some of the guide and/or straightening vanes are arranged in conjunction with the centre element at their base portions. The vanes may be fastened to the centre element by 5 welding, for example. An advantage of the invention is that it improves the separation of the material to be separated in the cyclone separator. 10 One advantage of the invention is that makes it possible to considerably reduce or even to prevent the passing of the gas and the material to be separated contained therein through the cyclone separator at the central axis of the separator. 15 Another significant advantage of the invention is the fact that it makes it possible to reduce the pressure drop in relation to the separation efficiency. The cyclone separator according to the invention may preferably be used in a method for separating material to be separated from a gas flow. The solutions 20 presented in the dependent claims and in the context of the examples presented in the figures are also suitable for use in the said method. Typically, a cyclone separator is arranged to be used vertically, whereby the inlet connection is arranged below the discharge connection. The gas flow to be 25 purified is lead to the cyclone separator at its lower part and the purified gas flow is discharged from the cyclone separator from its upper part. It is clear that the cyclone separator is suitable also for horizontal use. In a preferred embodiment of the invention, at least one separation opening is 30 arranged to the separator chamber, through which separation opening material separated from the gas to be purified can be discharged. The separation opening(s) may have been arranged at suitable points of the wall of the separator chamber. The diameter of the separation opening is normally clearly WO 2008/152203 PCT/F12008/050349 13 smaller than the diameter of the inlet connection andlor that of the discharge connection, typically about 0,07-0,15 m. If the cyclone separator is meant to be mounted in vertical position, i.e. vertically, to the lower part of the separator chamber, to the bottom of the separator chamber a discharge chute may have 5 arranged, to which chute the separation opening is arranged. In this case, the material to be separated settles along the walls of the separator chamber to the discharge chute, wherefrom it is discharged through the discharge opening. A discharge chute can also be arranged on the bottom of a horizontal cyclone separator. 10 BRIEF DESCRIPTION OF THE FIGURES In the following, the invention is described in more detail with reference to the attached schematic drawing, wherein Figure 1 illustrates a cyclone separator according to known prior art, 15 Figure 2 illustrates a cyclone separator according to the first embodiment of the invention, Figures 3a, 4a and 5a illustrate a cross section of the tubular inlet connection of 20 a cyclone separator and a perspective view of its guide vane, Figures 3b, 4b and 5b illustrate the situations presented in Figures 3a, 4a and 5a, as seen from the direction of the arrow d, 25 Figure 6a illustrates the change in the angle of the first surface of the guide vane in the main direction of the gas flow, Figure 6b illustrates the average change in the angle of the first surface of the guide vane in the radial direction, 30 Figure 7a is a perspective view of a cyclone separator according to the second embodiment of the invention, WO 2008/152203 PCT/F12008/050349 14 Figure 7b illustrates a cyclone separator according to one embodiment of the invention, the discharge connection of which is provided with straightening vanes, 5 Figure 8 illustrates some of the vanes and a centre element, similar to that shown in Figures 7a and 7b, arranged in the inlet connection, and Figure 9 illustrates schematically the change in the angle of the vane according to an embodiment of the invention. 10 DETAILED DESCRIPTION OF THE EXAMPLES PRESENTED IN THE FIGURES Figure 1 illustrates a cyclone separator 91 according to known prior art, which comprises a gas feed channel 95 and a gas discharge channel 96 and a 15 separator chamber 92 between them, which separator chamber has a discharge channel 97 for particles. The arrow 100 shows the flow direction of the gas. A guide vane group 98 of the infeed side is arranged in conjunction with a feed opening 93, which guide vanes are intended to bring the gas to be purified into a swirling motion. A vane group 99 on the discharge side is 20 arranged in conjunction with a discharge opening 94, which vanes are intended to straighten the flow coming from the separator chamber 92. Figure 2 illustrates a cyclone separator 1 according to the first embodiment of the invention. The arrow 10 shows the main direction of the gas flow in the inlet 25 channel 5, the separator chamber 2 and the discharge channel 6. The cyclone separator I has an inlet connection 3, through which the gas to be purified is fed into the separator chamber 2. A guide vane 8a is arranged in conjunction with the inlet connection 3, the first surface 12 of which guide vane is, in this example, arranged at an angle a of approximately 45 degrees in relation to the 30 main direction 10 of the gas flow. In this example, the main direction 10 of the gas flow is substantially the same as the direction of the common central axis 13 of the inlet connection 3 and of the separator chamber 2. The purpose of the guide vane 8a is to deflect the gas flow fed into the separator chamber 2 from WO 2008/152203 PCT/F12008/050349 15 its main direction 10 in such a way that at least part of the gas flow is directed towards the wall 11 of the separator chamber 2. At the same time, the gas flow is brought into a swirling motion in the separator chamber 2. When the gas swirls near the wall 11, material to be separated, such as water droplets or 5 particles, is separated from the gas by centrifugal force. This material is discharged through a separation opening 7. The gas is discharged from the separator chamber 2 through a discharge connection 4 and then further through a discharge channel 6. 10 Figures 3a, 4a and 5a show an example of a cross section of the tubular inlet connection 3 of a cyclone separator, in the direction perpendicular to the main direction of the gas flow. In Figures 3a, 4a and 5a, the direction of the gas flow passes perpendicularly from the viewer through the plane of the paper. Figures 3a, 4a and 5a illustrate a perspective view of the guide vane 8a. Figures 3b, 4b 15 and 5b illustrate the situations presented in Figures 3a, 4a and 5a above the tubular inlet connection, as seen from the direction of the arrow d. The purpose of these examples is to explain what is meant in this application by the angle of the first surface of the guide vane 8a in relation to the main direction 10 of the gas flow. In this example, the vane 8a is uniformly plate-like and straight, and it 20 is attached at its base portion 9 to the centre element 15a arranged in conjunction with the central axis. The centre element is not shown in Figures 3b, 4b and 5b. The longitudinal axis 18 of the vane 8a is arranged to be parallel to the radius of the inlet connection 3, i.e. from the centre element 15a perpendicularly towards the wall of the inlet connection 3. In Figures 3a and 3b, 25 the first surface 12 of the vane 8a is arranged at an angle of 90 degrees in relation to the main direction 10 of the gas flow, i.e. in Figure 3a the first surface 12 is parallel to the plane of the paper. In Figures 4a and 4b, the vane 8a has been turned by 45 degrees around its longitudinal axis 18 from the position in Figures 3a and 3b, in which case the angle a of the first surface 12 is 45 30 degrees in relation to the main direction 10 of the gas flow. In Figures 5a and 5b, the vane 8a has been turned by 90 degrees around its longitudinal axis 18 from the position in Figures 3a and 3b, in which case the angle of the first surface 12 WO 2008/152203 PCT/F12008/050349 16 is zero degrees in relation to the main direction 10 of the gas flow, i.e. the first surface 12 is parallel to the direction of the gas flow. Figure 6a illustrates what is meant by the change in the angle, and in this 5 particular case, an increase in the angle, of the first surface 12a, 12b of the guide vane attached to the centre element 15, in the main direction 10 of the gas flow. While moving in its main direction 10, the gas first meets the first part 12a of the first surface of the vane which is at a certain angle, for example, 10 degrees, in relation to the main direction 10 of the gas flow. As the gas moves 10 along the first part 12a of the first surface of the vane in its main direction 10, the angle of the first surface increases at fold 19, and in particular at point 19a, in such a way that the angle of the second part 12b in relation to the main direction 10 of the gas flow is greater than that of the first part 12a. The angle of the second part 12b may, for example, be 40 degrees. 15 Figure 6b illustrates what is meant by the average change in the angle of the first surface 12a, 12b of the guide vane in the direction substantially perpendicular to the main direction of the gas flow, i.e. in the radial direction. In this example, the angle of the first part 12a in relation to the main direction 10 of 20 the gas flow is smaller than the angle of the second part 12b. Most of the base portion 12b' of the vane is at a large angle and only a small proportion 12a' at a small angle in relation to the main direction 10 of the gas flow. Seen in the direction of the longitudinal axis 18 of the vane, i.e. in the radial direction of the cyclone separator, most of the outer edge of the vane 12a" is at a small angle 25 and only a small proportion 12b" at a large angle in relation to the main direction 10 of the gas flow. In this application, this property is described by stating that the angle of the first surface 12a, 12b is, on average, greatest in conjunction with the central axis 13 and decreases, on average, towards the wall of the cyclone separator, i.e. in the radial direction, i.e. in the direction of 30 the longitudinal axis of the vane. Figure 7a is a perspective view of a cyclone separator 1 according to the second embodiment of the invention. The inlet connection 3 of the cyclone WO 2008/152203 PCT/F12008/050349 17 separator 1 is provided with guide vanes 8a. The centre element 15 is cylindrical in shape. It is arranged in conjunction with the central axis of the separator chamber 2 and extends substantially from the inlet connection 3 to the discharge connection 4. The centre element 15 prevents the flow of gas into 5 conjunction with the central axis of the separator chamber 2 and thus forces the gas flow closer to the wall 11 of the separator chamber 2. The guide vanes 8a are attached to the centre element 15a by means of their base portions 9. From the point at which their base portions are attached, the vanes 8a protrude substantially perpendicularly to the direction of the centre element 15a and that 10 of the central axis towards the wall 11 of the cyclone separator. The angle of the first surface 12 of the vanes 8a is arranged to be variable in such a way that it increases in the main direction 10 of the gas flow, in other words, in the lateral direction of the vane. The first surface 12 of the vanes 8a has two folds 19, 20, which divide the first surface into three parts 12a, 12b, 12c. The number of folds 15 may also be different, 1, 3, 4, 5 or more, for example. The change in the angle of the first surface may also be arranged, at least partly, to be continuous without any distinct folds. In this example, the angle of the first part 12a in relation to the main direction 10 of the gas flow is small, approximately 5 degrees. The angle of the second part 12b is approximately 25 degrees and 20 that of the third part 12c is approximately 45 degrees. In conjunction with the inlet connection 3, the centre element 15a is conical and arranged so that it becomes wider in the main direction 10 of the gas flow. The conical shape directs the gas flow away from the central axis towards the wall 11 of the cyclone separator. The arrow 30 marked with a broken line shows how the 25 guide vane 8a directs the gas flow towards the wall. 11. The centre element 15b is conical at the discharge connection 4 and tapers in the main direction 10 of the gas flow, which helps to direct the gas flow back into conjunction with the central axis 14 of the discharge connection 4 and thus helps to even out the gas flow in the cross section of its flow. 30 Figure 7b illustrates a cyclone separator according to one embodiment of the invention, the discharge connection of which is provided with straightening WO 2008/152203 PCT/F12008/050349 18 vanes 8b. The purpose of the vanes is to straighten the turbulent gas flow discharged from the separator chamber 2. Figure 8 illustrates some of the vanes and the centre element similar to that in 5 Figures 7a and 7b arranged in the inlet connection, seen from the direction of the wall of the inlet connection parallel to the radius towards the centre element 15, 15a and the central axis. In Figure 8, the angle of the guide vanes is arranged to be variable in a direction different from that in Figures 7a and 7b. The vanes in Figure 8 direct the gas flow counter-clockwise and the guide 10 vanes in Figures 7a and 7b clockwise. Figure 9 shows schematically the change in the angle of the vane in an embodiment of the invention. A guide vane 12 is attached to the centre element 15, to which vane a fold 12' is arranged along to the broken lines. In the portion 15 12b of the vane 12 of the fold 12', on the side of the centre element 15, the angle of the first surface of the vane is 50 degrees in relation to the main direction 10 of the gas flow. When a particle A meets the first surface of the vane near the centre element 15, the particle A is directed along the first surface of the vane 12 in the portion where the angle of the vane 12 is, on 20 average, 50 degrees for the entire length of the vane. When a particle B meets the first surface of the vane in the middle portion of the vane, the particle B is directed at first with that portion of the vane which is at an angle of 40 degrees up to the fold in the vane, whereafter it is directed with the surface of the vane which is at an angle of 50 degrees. Thus, the angle used for directing the 25 particle B is on average smaller than the angle used for directing the particle A. When a particle C meets the first surface of the vane near the outer edge of the vane, the particle C is directed along the first surface of the vane 12 in that portion where the angle of the vane 12 is, on average, 40 degrees on the entire length of the vane. The angle of the first surface of the vane used for directing 30 the particle C is thus on average smaller than the angle used for directing particles A and B. In this way, particles entering the separator chamber in conjunction with the central axis can thus be directed more forcefully towards the wall than those which are closer to the wall already when entering the -19 separator chamber. The angles in Figure 9 are naturally given by way of examples, and they can vary within the limits presented in the claims. It is not intended that the invention be limited to the embodiments presented by way of 5 examples above, but it is intended to be interpreted widely within the protection scope defined by the claims presented below. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary 10 implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 15 It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. 25047491 (GHMaters)

Claims

1. A cyclone separator for separating the material to be separated from a gas flow, which cyclone separator comprises: 5 a separator chamber, an inlet connection for feeding gas into the separator chamber, and a discharge connection for discharging gas from the separator chamber, which separator chamber, inlet connection and discharge connection have a central axis and a wall, and 10 a separation opening for discharging the separated material from the separator chamber, and at least one guide vane in the inlet connection and/or separator chamber for directing the gas flow towards the wall of the cyclone separator, which guide vane has - a first surface and a longitudinal axis substantially parallel to it, and 15 - a base portion by means of which the guide vane is arranged in conjunction with the central axis of the inlet connection and/or that of the separator chamber, from where the first surface and the longitudinal axis are arranged radially so that they protrude towards the wall of the separator chamber and/or that of the inlet connection, 20 wherein at least a portion of the first surface of the guide vane is arranged, by turning it around its longitudinal axis or in a similar way, at an angle (a) which is 1-90 degrees, preferably 5-70 degrees, very preferably 10-60 degrees in relation to the main direction of the gas flow, whereby the angle (cx) of the first surface in relation to the main direction of the gas flow is arranged to be variable at least in the direction 25 substantially perpendicular to the main direction of the gas flow, i.e. in the radial direction, in such a way that the angle (cx) is greatest in conjunction with the central axis and decreases on average towards the wall of the cyclone separator.

2. A cyclone separator according to claim 1, wherein it also comprises at least one 30 straightening vane in the discharge connection for straightening the gas flow discharged from the separator chamber, which straightening vane has a first surface and a longitudinal axis substantially parallel to it, and a base portion by means of which the straightening vane is arranged in conjunction with the central axis of the discharge connection, from where the first 35 surface and the longitudinal axis are arranged radially so that they protrude towards the wall of the discharge connection, 2504149_1 (GHMatters) -21 and at least a portion of the first surface of the straightening vane is arranged, by turning it around its longitudinal axis or in a similar way, at an angle (a) which is 0 90 degrees, preferably 5-70 degrees, very preferably 10-60 degrees in relation to the main direction of the gas flow. 5

3. A cyclone separator according to claim 2, wherein the angle (a) of the first surface is arranged to be variable.

4. A cyclone separator according to any one of claims 1-3, wherein the angle (a) of the 10 first surface of the guide vane increases in the main direction of the gas flow.

5. A cyclone separator according to any one of claims 2-4, wherein the angle (a) of the first surface of the straightening vane decreases in the main direction of the gas flow. 15

6. A cyclone separator according to claim 1, wherein a larger proportion of the first surface of the base portion of the vane is at a greater angle than of the first surface at the outer edge of the vane.

7. A cyclone separator according to any one of claims 1-6, wherein it also comprises a 20 centre element, which is arranged substantially in conjunction with the central axis of the inlet connection and/or that of the separator chamber for directing the gas flow away from the central axis towards the wall of the cyclone separator.

8. A cyclone separator according to any one of claims 1-7, wherein it also comprises a 25 centre element, which is arranged substantially in conjunction with the central axis of the discharge connection.

9. A cyclone separator according to claim 7 or 8, wherein the centre element is cylindrical at least in conjunction with the central axis of the separator chamber. 30

10. A cyclone separator according to any one of claims 7-9, wherein at least some of the guide vanes and/or straightening vanes are arranged at their base portions in conjunction with the centre element. 35

11. A method for separating material from a gas flow in a cyclone separator, whereby

2504749.1 (GHMatters) - 22 gas containing material to be separated is directed via the inlet connection of the cyclone separator to its separator chamber, and at the same time said gas is directed from the central axis of the inlet connection and/or the separator chamber of the cyclone separator towards its wall by means of at least one guide vane 5 arranged in the inlet connection and/or separator chamber, which guide vane has - a first surface and a longitudinal axis substantially parallel to - it, and - a base portion by means of which the guide vane is arranged in - conjunction with the central axis of the inlet connection and/or 10 - that of the separator chamber, from where the first surface and - the longitudinal axis are arranged radially so that they protrude - towards the wall of the cyclone separator, - the gas from which the material has been separated is discharged from the separator chamber of the cyclone separator through the discharge connection, 15 the separated material is discharged through the separation opening located in the separator chamber of the cyclone separator, wherein said gas is directed towards the wall of the cyclone separator by arranging at least a portion of the first surface of the guide vane, by turning it around its longitudinal axis or 20 in a similar way, at an angle (a) which is 1-90 degrees, preferably 5-70 degrees, very preferably 10-60 degrees in relation to the main direction of the gas flow, and the angle (cc) of the first surface in relation to the main direction of the gas flow is arranged to be variable at least on average in the direction substantially perpendicular to the main direction of the gas flow, i.e. in the radial direction, in such a way that the angle (cc) is 25 greatest in conjunction with the central axis and decreases, on average, towards the wall of the cyclone separator.

12. A method according to claim 11, wherein the flow at the central axis of the cyclone separator is prevented or it is decreased by using a centre element. 30

13. A method for enhancing the separation of particles in a cyclone separator comprising a separator chamber, whereby - gas flow containing particles is lead to the separator chamber through the inlet connection located at its first end, 35 - said gas flow containing particles is directed along the surface of at least one guide vane arranged in the inlet connection or the separator chamber, whereby 25047491 (GHMatters) -23 the gas flow is brought in motion towards the other end of the separator chamber and the particles are directed towards the outer wall of the cyclone separator, - gas flow is lead out from the separator chamber through the discharge 5 connection located at the other end of the cyclone separator, wherein a particle that meets the surface of the guide vane near the centre portion of the cyclone separator is directed to travel at a greater angle towards the outer wall of the cyclone separator than a particle that meets the guide vane further away from the 10 centre portion of cyclone separator.

14. A separator, or a method for separating, or a method for enhancing separation, substantially as herein described with reference to the accompanying drawings. 2504749_1 (GHMatter)