WO2016064269A1

WO2016064269A1 - Centrifugal separator, cartridge unit therefor

Info

Publication number: WO2016064269A1
Application number: PCT/NL2015/050727
Authority: WO
Inventors: Hendrik Arie Boele
Original assignee: Evodos B.V.
Priority date: 2014-10-21
Filing date: 2015-10-21
Publication date: 2016-04-28
Also published as: NL2013662B1; WO2016064269A8

Abstract

A centrifugal separator comprising a rotatably arranged upwardly extending first element with elongate elements connected thereto and an upwardly extending rotatably arranged second element, wherein the first element and the second element are approximately concentrically arranged with respect to each other resulting in an inner element and an outer element providing a separation chamber therebetween, wherein the outer element is removable with respect to the inner element and wherein the elongate elements extend from the first element towards the second element, further comprising a stationary feed tubefeed tube arranged centrally with respect to the first element and the second element, wherein between the supply tube and the inner element a rotatable coupling tube is arranged that is coupled to the feed tubefeed tube to form a cartridge unit that is exchangeable from the separator.

Description

Title: Centrifugal separator, cartridge unit therefor.

The invention relates to a centrifugal separator.

Centrifugal separators are commonly known and are generally used for separating particles or components from a dispersion comprising said particles, such as a slurry. A slurry can be considered as a system in which particles or droplets are mixed with a carrying fluid in a continuous phase of a different composition, e.g. a mud being a slurry comprising clay particles in water, living algae in water, contaminant particles in lubricant, water in oil, or tar sand comprising oil, or drilling muds comprising solids, etc. A slurry may comprise two or more phases, such as a suspended phase and a continuous phase. The suspended phase may be solid or liquid. The continuous phase is a fluid, viz. a gas or a liquid, usually a liquid. Thus, a slurry is a fluid carrying one or more solid and/or liquid particles. The particles may be for example solid particles suspended by the fluid or may be liquid particles suspended by a fluid.

The principle of a centrifugal separator is commonly known. The centrifugal separator creates an artificial field of gravity by using the centrifugal force. Due to the difference in specific density of the different particles in the slurry one or more particles may be separated and collected. For example, a well known separator is the Evodos®-separator described in WO 2009/005355. This separator has found a wide field of use and is being used for the separation of various types of dispersions and/or slurries. In practice, when using the separator with for example heavy and/or abrasive slurry materials, it is observed that the life time of some components of the separator may be reduced, reducing the interval time between subsequent maintenance services. Also, maintenance may be complex and time consuming. As the separator is not operational during maintenance, operators may consider a reduced maintenance interval as a drawback. So, there is a need to improve the operational time of the separator, in particular when working with heavy and/or abrasive materials. Publication WO 2006/099565 discloses a fluid-processing centrifuge having a rotor assembly that comprises a rotor housing connected to a rotor base and a spiral vane insert. The rotor housing and rotor base provide for a hollow interior within which the spiral vane insert can be inserted. The spiral vane insert includes the spiral vanes, and the rotor base includes the rotor center tube with outlet openings through which the fluid to be processed is introduced into the vane insert where it is processed to separate out the heavier particulate. The heavier particulate collects along the inside surface of the insert and the processed fluid exits from the inert. The spiral vane insert is removable for disposal once it collects its designed volume of heavier particulate sludge from the fluid processing.

It is an object of the invention to provide for a centrifugal separator that obviates at least one of the above mentioned drawbacks, while maintaining the advantages.

Thereto, the invention provides for a centrifugal separator according to claim 1.

By providing a centrifugal separator with a cartridge unit, the time that the separator is not operational due to maintenance may be reduced. By providing the cartridge unit, the cartridge unit may be removed from the separator and may be replaced by another cartridge unit. Then, the removed cartridge unit may be serviced separately, while the separator may be in operation again. As such, the service time required for maintenance may be reduced, while optimizing the operational time of the separator, even when working with abrasive and/or heavy suspension materials that give a lot of wear to the components coming in contact with the suspension material. Advantageously, components of the separator coming in contact with the slurry form part of the cartridge unit and thus may be exchanged relatively easy to increase the operational time of the separator.

Preferably, the cartridge unit comprises at least the feed tube. According to the invention, to facilitate exchange of the cartridge unit with the separator, the cartridge unit further comprises a coupling tube that is arranged between the feed tube and the inner element. The coupling tube is arranged for coupling to the feed tube and to the inner element.

Advantageously, the feed tube is stationary, so the feed tube is preferably coupled to the feed tube in a way that allows rotation e.g. by means of a bearing. Preferably, the coupling tube is rotationally coupled to the inner element, as to rotate together with the inner element, e.g. by means of bolts or other connection means. Of course, in an other embodiment, the coupling tube can be stationary as well.

Contrary to the prior art, the cartridge unit provides for inserting and removing of components of the centrifugal separator that may be required for introducing the product to be processed into the separation chamber, e.g. feed tube, and/or for exiting the processed fluids out of the separation chamber, e.g. an outlet unit. In the prior art centrifuges having an insert, the insert is there for removing the surface that collects the processed particles, i.e. a complete separation chamber.

By providing a cartridge unit, a centrifugal separator of a modular construction is provided. By providing different types of cartridges, the centrifugal separator can relatively easily be adapted for different processes. As such, the inner and outer element may form a basis or platform, whereby the cartridge provides for the modular functionality in that by using different cartridges a different separator can be provided. This may allow for a great flexibility in use of the separator. Also, manufacturing,

maintenance and/or exploration of the separator can become more cost effective. For example, during the lifetime of the centrifugal separator, the separator can be used for different types of fluid to be processed, by exchanging the cartridge unit depending on the type of fluid to be processed. This may give a cost advantage for the user of the centrifugal separator. Alternatively, by providing a modular centrifugal separator, a multitude of the same components, such as inner and outer elements, can be

manufactured and can be tailor made for a specific situation and/or customer by providing for a different type of cartridge. As such, a basis or platform for the centrifugal separator is provided which can be modularly adapted by providing a different type of cartridge unit depending on situation and/or customer. Manufacturing time and/or costs may thus be reduced and flexibility for the user may be increased.

To provide for this modular functionality, the cartridge unit may or may not comprise the feed tube. Also, the cartridge unit may or may not comprise the outlet unit. Advantageously, the cartridge unit comprises the feed tube and/or the outlet unit as these units may vary depending on the fluid to be processed and/or on other situational circumstances. Then, the modular functionality can be more optimally provided.

For example, one type of cartridge unit may be suitable for fluid- solid separation. In this embodiment, an outer ring of outlet ports from the separation chamber can be used to allow a relatively large inner diameter of the fluid cyhndrical column during separation and to allow a limited layer of solid particles per batch.

For example, another type of cartridge unit may be suitable for fluid-solid separation. In this embodiment, an inner ring of outlet ports from the separation chamber can be used providing for a fluid cylindrical column during separation having a smaller diameter, compared to the previous example. This allows for a larger processed volume, but possible lower separation efficiency.

For example, another type of cartridge may be suitable for fluid- fluid separation and/or for fluid-fluid-solid separation. In this embodiment, both the inner ring of outlet ports and the outer ring of outlet ports from the separation chamber is used during the separation.

In the above examples, typically the separation chamber provided by the inner element and the outer element is provided with an inner ring of outlet ports and an outer ring of outlet ports, typically provided in a bottom or a bottom flange of the separation chamber. By providing different types of cartridges the inner ring and/or the outer ring of outlet ports can be blocked for use during separation. As such, at least the inner and outer element provide a basis or platform for a modular centrifugal separator which can be completed by inserting a different type of cartridge unit.

The coupling tube is preferably rotationally coupled with the inner element, so that, in use, it rotates together with the inner element around the feed tube, while the feed tube is stationary. The coupling tube is coupled with the feed tube, such that it can be removed from the separator together with the feed tube as a cartridge unit. In an advantageous embodiment, the coupling tube may be coupled with the feed tube via bearings.

Further, the feed tube may comprise supply elements at an end of the feed tube. Via the supply elements the slurry can be entered into the separation chamber. The supply elements may for example be supply tubes extending in the separation chamber, or may be supply openings in a wall of the feed tube and/or the wall of the first element. By providing supply elements, in particular supply tubes, the material to be separated, i.e. the slurry, may be supplied at an effective region in the separation chamber. Advantageously, the supply tubes are removable arranged, such that they first may be removed before exchanging the cartridge unit comprising the feed tube.

In an advantageous embodiment, further a supply chamber is provided at an end of the feed tube. The supply chamber may be provided with the supply elements, such as the supply tubes or the supply openings. The supply chamber may form a chamber in which the material to be separated, i.e. the slurry, may be collected prior to releasing it in the separation chamber via the supply elements.

Advantageously, in the supply chamber the pressure is higher than in the separation chamber, in use, such that the material to be separated may be said to being "pushed" into the separation chamber or being

"sucked" into the separation chamber. To that end, the supply chamber may comprise an inner wall tapering outwardly towards the supply elements. In an embodiment, the supply chamber may thus have a conical shape that widens out from a diameter corresponding approximately to the diameter of the feed tube to a wider diameter at which the supply elements are arranged. Due to the centrifugal force in the separation chamber, when the inner and outer element are rotating, various particles of the slurry may form different cylindrical columns, depending on their specific density. The higher the specific density of the particle, the more outwardly the cylindrical column of that particle is formed in the separation chamber, i.e. the larger the radius of the column formed by said particle. Since the distance between the outer radius of the separation chamber, where the slurry is, and the outer diameter of the supply chamber is larger than the distance between the outer radius of the separation chamber and the radius of the particle column in the separation chamber, an over-pressure occurs in the supply chamber. The column formed by the particles and/or droplets may be cylindrical, but may also be conical.

Due to the over-pressure in the supply chamber, the slurry may be drawn out of the supply chamber via the supply elements into the

separation chamber. The supply chamber, in combination with the supply elements can thus be considered acting as a pump. To that end, the supply chamber may comprise an inner wall tapering outwardly towards the supply elements. In an embodiment, the supply chamber may thus have a conical shape that widens out from a diameter corresponding to the diameter of the feed tube to a wider diameter at which the supply tubes are arranged.

Advantageously, the supply chamber forms part of the cartridge unit, such that it can be removed and replaced relatively easily.

In an embodiment of the centrifugal separator, the material to be separated is supplied at one end of the separation chamber and at an opposite end of the separation chamber at least one outlet is provided.

Multiple outlets may be provided, depending on the number of different particles, or different phases, to be separated. For each separated phase an outlet may be provided at different radial distance. Also, multiple outlets may be provided for a single phase which may be approximately equally distributed over a radius to collect the separated particles. For example, in an embodiment the supply elements may be at an upper end of the separation chamber and the outlet may be at a lower end of the separation chamber. Alternatively, the supply elements may be at a lower end of the separation chamber and the outlet at the upper end of the separation chamber.

The outlets may extend into an outlet unit connected to the separator. Advantageously, the outlet unit is rotationally coupled to the separation chamber, e.g. via the inner element, or via the coupling tube. This way the separated particles may effectively be transported out of the separator and collected elsewhere. In an advantageous embodiment, a pump may be provided in the outlet housing to pump the separated particles out of the separation chamber to collect them elsewhere. The pump may be a centripetal pump of which the housing may be stationary and coupled to the feed tube and the blades may be rotatable and coupled to the inner element and/or coupling tube. Thus, a compact and effective outlet unit may be provided to remove the separated particles from the separation chamber. Preferably, the outlet unit is part of the cartridge unit as well to be removed and/or exchanged at once together with the other parts of the cartridge unit.

According to the invention, the cartridge unit comprises multiple parts of the centrifugal separator that may be subject to relatively heavy wear, e.g. due to coming in contact with abrasive material. The multiple parts may be coupled together such that they can be handled as a cartridge unit, i.e. as a single compound part of the separator. The cartridge unit can thus be relatively easily removed, exchanged and/or replaced from/to the separator, thereby reducing the downtime for maintenance of the separator and increasing the operational running time.

Further advantageous embodiments are represented in the subclaims.

The invention further relates to a method for providing

maintenance of a centrifugal separator, and to a cartridge unit for a centrifugal separator.

The invention will further be elucidated on the basis of exemplary embodiments which are represented in a drawing. The exemplary

embodiments are given by way of non-limitative illustration.

In the drawing:

Fig. 1 shows a schematic cross-sectional view of an embodiment of the centrifugal separator;

Fig. 2 shows a schematic cross-sectional view of another

embodiment of the centrifugal separator;

Fig. 3 shows a schematical perspective view of an embodiment of the centrifugal separator.

It is noted that the figures are only schematic representations of embodiments of the invention that are given by way of non-hmiting example. In the figures, the same or corresponding parts are designated with the same reference numerals.

Figure 1 shows a cross-sectional view of a centrifugal separator 1 according to an aspect of the invention. The centrifugal separator 1 comprises a rotatably arranged upwardly extending first element 2 and an upwardly extending rotatably arranged second element 3.

The first element 2 is provided with outwardly extending elongate elements 4. The elongate elements 4 extend from the first element 2 towards the second element 3. The elongate elements 4 may typically be vanes or blades. The elongate elements 4 are flexible and/or flexibly mounted to the inner element 2. Multiple elongate elements 4 are arranged around the first element 2 and connected thereto. This can for example be seen in figure 3. In the embodiment of figure 1 two blade packs 5 are arranged above each other. In an other embodiment one blade pack 5 may be provided, as in figure 3, or more than two blade packs 5 may be provided. A number of elongate elements, or blades, 4 that are arranged circumferentially arranged over the same height around the first element 2 may be considered as a blade pack 5. In the embodiment of figure 1, there are two blade packs 5, one arranged above another.

The centrifugal separator 1 can be used for separating one or more particles and/or droplets from a liquid, e.g. separating solid particles dispersed in a liquid from the liquid, or separating different dispersed liquids such oil and water. From the centrifugal separator 1 the solid particles can be collected as well as liquid particles. Typically, the solid particles attach to the elongate elements and the liquid particles are removed via outlets from the separator 1.

The first element 2 and the second element 3 are approximately concentrically arranged with respect to each other resulting in an inner element and an outer element. Here, the first element 2 and the second element 3 are concentrically arranged around a central axis A. The central axis A is here the rotation axis as well. The first element 2 is approximately centrally arranged in the second element 3. In this configuration, the first element 2 forms the inner element, and the second element 3 forms the outer element. For reasons of conciseness the inner element and the first element, being the same element here, are referred to with the same reference numeral 2. Idem, the outer element and the second element are referred to with the same reference numeral 3, forming the same element of the separator 1. Nevertheless, it may be understood that in another embodiment, the first element may be the outer element and the second element may be the inner element. The first element 2 and the second element 3 are here provided as cylindrical elements, but may have other cross-sectional shapes, such as triangular or rectangular or oval etc. The first and the second element 2, 3 extend in longitudinal direction along the central axis A.

Between the inner element 2 and the outer element 3, a separation chamber 6 is provided. The elongate elements 4 are arranged in the separation chamber 6. In the separation chamber 6, separation takes places under the influence of the centrifugal force. The separation chamber 6 is closed at a lower end 6a with a bottom flange 7 and at an upper end 6b closed with a top flange 8.

The outer element 3 is removable with respect to the inner element 2. By removing the outer element 3, the separation chamber 6 becomes accessible. The inner element 2 becomes free of the outer element 3. Also, by rotation of the inner element 2 when the outer element 3 is removed, solid particles accumulated on the vanes 4 during separation, may be launched from the vanes and may be collected for further processing. The vanes 4 can thus be cleaned. When the vanes 4 are cleaned, the outer element 3 can be placed over or around the inner element 2 again and the separator 1 can be closed for a further separation run.

The outer element 3 can be removable in axial direction, e.g. that it can be moved up or downwards. In another embodiment, the outer element 3 can be removed in radial direction with respect to the inner element 2, e.g. when the outer element 3 is provided in segments or sections. Many variants are possible.

In use, the inner element 2 and the outer element 3 are

mechanically coupled via the elongated elements 4. The vanes 4 are connected to the inner element 2 and rest against the outer element 3, so during rotation the inner element 2 and the outer element 3 are rotated with the same rotational speed. In this embodiment, the inner element 2 is driven by a drive unit, e.g. a motor, and set into rotation by the motor, due to the mechanical coupling of the outer element 3 with the inner element 2, via the vanes 4, the outer element 3 is also rotated. Alternatively, the inner element 2 and the outer element 3 may be driven by different drive units at the same rotational speed, for example via electronical or mechanical synchronization, or may be driven by the same drive unit having two output axes, one output to the inner element and one output to the outer element. When removing the outer element, the outer element may be uncoupled from the drive unit.

The separator 1 further comprises a feed tube 9. The feed tube 9 is stationary and is arranged centrally with respect to the first element 2 and the second element 3. Here, the feed tube 9 is provided as a hollow tube arranged around the central axis A, in particular a central axis of the feed tube 9 coincides with the central axis A of the separator 1.

At a lower end 9a of the feed tube 9 the slurry, i.e. the material to be separated is supplied to the feed tube 9. At an opposite end, here the upper end 9b of the feed tube 9, the slurry is supplied to the separation chamber 6. The upper end 9b of the feed tube 9 is closed with a flange 10.

The slurry is entered into the separation chamber 6 via supply elements 11. In the embodiment of figure 1, the supply elements 11 are embodied as supply tubes 11 extending into the separation chamber 6. In the embodiment of figure 2, the supply elements 11 are provided as supply openings 11 in the first element 2. In an alternative embodiment, not shown here, the supply elements 11 may be provided as stationary supply tubes 11 mounted to the stationary feed tube 9 and extending into the separation chamber 6. By providing supply tubes, erosion and/or abrasion of the openings in the inner element may be obviated as the supply tubes may protect the openings in the inner element from contact with the slurry. At the position of the stationary supply tubes 11, the inner element 2 may be interrupted, e.g. provided with a groove, such that it can rotate around the stationary supply tubes. The supply tubes 11 may be mounted into the stationary feed tube 9, for example at an upper end thereof, while the inner element 2 is, during use, rotating around it. So, bearings and/or seals may be provided to seal the passage of the supply tubes 11 through the inner element 2.

In an alternative embodiment, the supply elements 11, may be embodied as supply tubes which may rotate together with the inner element 2. The supply tubes 11 may then for example be mounted to the inner element 2.

Multiple supply tubes 11 may be provided which may extend radially outwardly into the separation chamber 6, but alternatively, the supply tubes may be inclined or may extend from a top side or a bottom side into the separation chamber. Multiple supply tubes 11 may be provided which may be evenly distributed circumferentially around the inner element 2.

The supply tubes 11 are advantageously removable connected to e.g. the inner element 2 or the feed tube 9, for example, via a screw- connection, or a click connection or a bayonet-connection. Many variants to removable mount the supply tubes are possible.

In an alternative embodiment, additionally a supply chamber 12 may be provided at an end of the feed tube 9, as shown in figure 1 as well as in figure 2. The supply chamber 12 is rotatable arranged with respect to the stationary supply tube 9. The supply tubes 11 are arranged in the supply chamber 12. In the embodiment of figure 1, the supply chamber 12 is formed by a rotatable insert 13 with inner walls 13a to which the supply tubes 11 can be mounted. It may be understood that, instead of an insert alternative embodiments may be possible to form a supply chamber. In the embodiment of figure 2, the supply chamber 12 is formed by the walls of the inner element 2 in which openings as supply elements 11 are arranged.

Alternatively, instead of openings as supply elements 11, supply tubes 11 may be mounted to the inner element 2. Further, the separator 1 comprises a coupling tube 14 arranged between the inner element 2 and the feed tube 9. The coupling tube 14 is rotatable connected with the inner element 2, such that, in use, the coupling tube 14 rotates together with the inner element 2. The coupling tube 14 is also connected to the feed tube 9, such that it can rotate around the stationary feed tube 9, but also can be handled as a single component together with the feed tube 9 to form a cartridge unit 15. The cartridge unit 15 is illustrated in the drawing by a dotted line. The cartridge unit 15 is here formed by at least the feed tube 9 and the coupling tube 14. The coupling tube 14 may for example be connected to the feed tube 9 with connection elements 25 such as bearings and/or other sealing members.

The connection elements 25, such as bearings 25, as shown in figures 1 and 2, are provided to couple the rotatable coupling tube 14 with the stationary feed tube 9, such that, in use, the coupling tube 14 may rotate around the feed tube 9. Further, the bearings 25 may be provided to center and hold the feed tube 9, and they may receive horizontal forces. In the embodiments of figure 1 and 2, an upper bearing 25a and a lower bearing 25b are provided. The upper bearing 25a may hold and center the feed tube 9 in the coupling tube 14 and/or may receive horizontal forces and/or may damp some vibration during rotations. The lower bearing 25b may mainly provide for receiving horizontal force in case of extreme swinging of the separator, e.g. due to a high rpm and/or imbalance of the separator. As such, the lower bearing 25b may provide for a safety function to hold the

separator and/or to limit extreme swinging motions.

The separator 1 may be mounted to a machine frame (not shown in the figures). Advantageously, the rotating parts of the separator are mounted to the machine frame via a top bearing through which the rotating axis of the rotating parts is centered. The top bearing is movable mounted to allow horizontal movement, limited by springs and/or bearings. During rotation, the rotating parts of the separator rotate around the rotating axis and the top bearing. Since the top bearing may move horizontally, the rotating axis may differ from the constructional center line (A) during rotation. Thus, the rotating parts of the separator may have some kind of "gyroscopic" movement around the top bearing. The top bearing is a self- adjusting bearing that may center the stationary feed tube and may limit vibrations.

The lower bearing, in the figures embodied as bearing 25b, may offer a safeguard in case of extreme swinging motions. The lower bearing limits swinging, e.g. when the separator is not in balance as when rotation without the outer element to remove the solid particles. The lower bearing then may receive horizontal forces and limit swinging motion. The stationary feed tube is stationary coupled to the machine frame, e.g. with rods and/or dampers etc., and thus can remain stationary during rotation.

In an embodiment, the supply chamber 12 and/or the supply elements 11 may be connected to the inner element 2 to rotate together with the inner element 2 during use. In the embodiment of figure 1 for example, the insert 13 of the supply chamber 12 is connected to the coupling tube 14 and as such to the inner element 2. The cartridge 15 thus comprises, in the embodiment of figure 1, the insert 13 of the supply chamber 12 as well. In the embodiment of figure 2 for example, the cartridge 15 comprises the coupling tube 14 and the feed tube 9 since the supply chamber 12 is formed by the walls of the inner element 2. In an other embodiment, the cartridge unit 15 may comprise the coupling tube and the outlet unit, depending on the situational circumstances.

Alternatively and/or additionally, the coupling tube 14 may be connected to the supply chamber 12, e.g. the coupling tube 14 may be connected with the insert 13 of the supply chamber 12. Due to rotation of the coupling tube 14, the chamber insert 13 may rotate as well, thereby providing a centrifugal force in the supply chamber 12. Advantageously, the supply chamber 12 forms part of the cartridge unit 15 and can be removed together with the coupling tube 14 and the feed tube 9. The coupling tube 14 may be fixedly connected with the insert 13 of the supply chamber 12, e.g. via bolts, or welding etc. The stationary feed tube 9 may then protrude somewhat in the supply chamber 12, but is not connected thereto. Typically, a narrow split may be present between the rotatable supply chamber 12 and the stationary feed tube 9. Since the slurry may be sucked out of the supply chamber 12, as will be described below, a sealing may be absent between the rotatable supply chamber 12 and the stationary feed tube 9.

The slurry in the chamber 12 being subject to the centrifugal force may be swung against the inner wall surface 13a of the supply chamber 12, having a radius Rl. The separation chamber 6 has an outer radius R2, and due to the specific density of particles in the slurry, one of the particles may form, during rotation, a column with radius R3. Since, during use, the difference between the radius R2 and the radius Rl is larger than the difference between the radius R2 and the radius R3, an over-pressure is created in the supply chamber 12, or, the pressure in the separation chamber 6 is lower than the pressure in the separation chamber 12. Due to this pressure difference, the slurry may be pushed into the separation chamber 6, so the supply chamber 12 may act as a pump. This may in particularly advantageous for heavy and/or viscous materials.

Advantageously, the inner wall surface 13a of the supply chamber 12 may extend outwardly, or may flare outwardly, or may taper outwardly to improve the pumping function of the supply chamber 12.

The cartridge unit 15 is, as a single component, removable and/or exchangeable and/or replaceable from the separator 1. Thus, a modular centrifugal separator can be provided using the same base components, e.g. the inner element and the outer element, and an exchangeable cartridge unit. The cartridge unit can be adapted depending on the specific situational circumstances (e.g. volume, fluid to be separated, etc.) or different types of cartridge units may be available, wherein the suitable type of cartridge is provided for the specific situation. This may significantly reduce downtime due to maintenance and/or may decrease manufacturing costs and/or operational costs. Also, this may increase the flexibility in use of the separator. For example with heavy and/or abrasive materials to be separated, the parts of the separator coming most into contact with the material to be separated may be subject to relatively heavy wear, which may require more and/or more often maintenance. By providing the cartridge unit 15, the downtime due to maintenance may be reduced, thereby the operational running time may be optimized.

Advantageously, the coupling tube 14 is coupled to the inner element 2 with removable coupling elements, e.g. a bolt-connection, or a click connection or a bayonet-connection etc. Upon removing the coupling elements, the cartridge unit 15 then may come loose from the remainder of the separator 1 and can be taken out of the separator 1.

In this embodiment, the material to be separated is supplied at the upper end 6b of the separation chamber 6 via the supply tubes. Separated particles may be removed from the separation chamber 6 at the opposite, lower end 6a, of the separation chamber 6 via outlets 16.

Since separation of components from the slurry is based on the difference in specific density of the components suspended in the slurry, multiple types of components, each type having a different specific density, suspended in the slurry, may be separated. A slurry can be considered as a system in which components, e.g. particles or droplets, are mixed with a carrying fluid in a continuous phase of a different composition. The different types of components, preferably fluid components such as droplets, having a different specific density may form different concentric columns in the separation chamber. Thus, when providing outlets at a specific radial distance from the rotation axis A, in the liquid column of the type of component to be separated, the particles can be collected with the outlets provided. Multiple outlets 16 may thus be provided at different radial positions with respect to the inner element 2, to collect different types of fluid components. Here, an outlet 16a is provided at a first radial distance to collect a first type of component, e.g. forming a column with radius R3, and an outlet 16b is provided at a second radial distance to collect a second type of component, e.g. forming a column with radius R4. Solid components may adhere to the vanes 4 and can be swung away when rotating the inner element 2 after the outer element 3 has been removed. The solid

components can then be collected outside of the separation chamber 6.

Additionally and/or alternatively, multiple outlets may be provided circumferentially at the same radial distance with respect to the inner element 2 as to allow to sufficiently collect the separated components. For example in figure 3 multiple outlets 16 are shown.

The outlets 16 may be arranged as outlet ports 17a in the bottom flange 7 of the separator 1 which may continue to an outlet channel 17b. The outlet channel 17b may be provided in an outlet unit 18 comprising an outlet housing 19. The outlet housing 19 is in an embodiment rotatable connected with the inner element 2, as to rotate together with the

separation chamber 6 in use. Alternatively, the outlet unit 18 may be stationary, and as such may be connected to the feed tube 9.

The outlet unit 18 may comprise a pump 20 provided in the outlet housing 19 and connected to the outlet channel 17b. By providing a pump 20, the separated particles may be removed more swiftly out of the separation chamber to be collected elsewhere. In an advantageous

embodiment, the pump 20 is a centripetal pump having a stationary housing 20a and rotatable vanes 20b. In an embodiment, the housing 20a of the pump 20 may be connected to the stationary feed tube 9 and the vanes 20b may be connected to the inner element 2 and/or the flange 7 to rotate together with the inner element 2. So, by providing a relatively simple configuration, an effective pumping function may be obtained. In another embodiment, the outlet channel may go directly out of the outlet unit 18, as for example shown for outlet 16b.

In an advantageous embodiment, the outlet unit 18 forms part of the cartridge unit 15 and is connected to the coupling tube and/or the feed tube. Also the outlet unit 18, e.g. the outlet channels 17b, may be subject to more wear when the separated particles may be abrasive and/or heavy. By providing the outlet unit 18 as a part of the cartridge unit 15, the downtime may further be reduced.

The outlet unit 18 may be provided as a separate part that may be fixedly connected to the coupling tube 14, e.g. via welding or bolting or screwing or any other well known connection. In the embodiments shown in figure 1 and figure 2, the outlet unit 18 is connected to the lower flange 7 via a connection element 21, here a bolt. Of course, other removable connection elements may be provided as well. Advantageously, multiple connection elements or bolts 21 are provided to connect the cartridge unit 15 to the inner element 2 and/or flange 7. By removing the bolts 21, the cartridge unit 15 can come loose from the separator 1 and may be taken out of the separator 1. The cartridge unit 15 may then be replaced by another cartridge unit, such that the separator may be operational again. The removed and/or worn cartridge unit may then be serviced at another location, e.g. at a service or repair shop, and/or at another time.

In use, the slurry is supplied via the feed tube 9. In the supply chamber 12 the pressure difference with the separation chamber is increased to due to the outwardly extending wall 13 of the supply chamber 12 and the slurry is then sucked into the separation chamber 6 via the supply tubes 11. The slurry enters the separation chamber 6 at one end, here the upper end 6b, and separated particles are removed from the separation chamber 6 at an opposite end, here the lower end 6a. During rotation, sohd particles attach to the vanes 4. After a separation run, e.g. when the vanes 4 are saturated with sohd particles, the outer element 3 can be removed from the inner element 2. When rotating the inner element 2, the vanes 4 are swung straight under influence of the centrifugal force and the solid particles may be launched from the vanes 4. The vanes 4 can thus be cleaned. After cleaning of the vanes 4, the outer element 3 can be mounted around the inner element 2 again and a next separation run can take place.

When maintenance may be required for e.g. the feed tube, outlet unit etc. due to for example wear on these components, the cartridge unit 15 can be removed from the separator 1 and can be replaced by another cartridge unit 15. For removing the cartridge unit 15, the outer element 3 is removed. Then, the supply tubes 11 are accessible. The supply tubes 11 can then be removed from the feed tube, e.g. by unscrewing them from the feed tube. Then, the cartridge unit 15 can be made loose from the separator by removing the connection elements 21, here by removing the bolts 21. When the bolts 21 are removed, the cartridge unit is uncoupled from the separator and can be taken out of the separator. The cartridge unit can then be exchanged by another cartridge unit, and can be serviced elsewhere independently from the operation of the separator. So, the downtime for maintenance may be reduced.

For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include

embodiments having combinations of all or some of the features described. It may be understood that the embodiments shown in figure 1 and figure 2 have the same or similar components, apart from where they are described as being different.

Many variants will be apparent to the person skilled in the art. All variants are understood to be comprised within the scope of the invention defined in the following claims.

Claims

1. A centrifugal separator comprising a rotatably arranged upwardly extending first element with elongate elements connected thereto and an upwardly extending rotatably arranged second element, wherein the first element and the second element are approximately concentrically arranged with respect to each other resulting in an inner element and an outer element providing a separation chamber therebetween, wherein the outer element is removable with respect to the inner element and wherein the elongate elements extend from the first element towards the second element, further comprising a stationary feed tube arranged centrally with respect to the first element and the second element, wherein between the feed tube and the inner element a rotatable coupling tube is arranged that is coupled to the feed tube to form a cartridge unit that is exchangeable from the separator.

2. The centrifugal separator according to claim 1, wherein the rotatable coupling tube is rotationally coupled to the stationary feed tube.

3. The centrifugal separator according to claim 1 or 2, further comprising supply elements extending in the separation chamber to supply slurry from the feed tube into the separation chamber.

4. The centrifugal separator according to claim 3, wherein the supply elements are provided as supply tubes that are removable arranged.

5. The centrifugal separator according to any of the preceding claims, further comprising a supply chamber, provided with the supply elements, rotatable arranged at an end of the feed tube.

6. The centrifugal separator according to claim 5, wherein the supply chamber comprises an inner wall surface tapering outwardly towards the supply tubes.

7. The centrifugal separator according to claim 5 or 6, wherein the supply chamber forms part of the cartridge unit.

8. The centrifugal separator according to any one of the preceding claims, wherein the material to be separated is supplied at one end of the separation chamber and wherein at an opposite end of the separation chamber at least one outlet is provided to remove the separated fluids.

9. The centrifugal separator according to claim 8, wherein the at least one outlet extends in an outlet unit comprising at least one pump for removing the separated fluid from the separator.

10. The centrifugal separator according to claim 7, wherein the outlet unit forms part of the cartridge unit.

11. Method for providing maintenance of a centrifugal separator comprising

- providing a centrifugal separator comprising a rotatably arranged upwardly extending first element with elongate elements connected thereto and an upwardly extending rotatably arranged second element, wherein the first element and the second element are approximately concentrically arranged with respect to each other resulting in an inner element and an outer element providing a separation chamber therebetween, wherein the outer element is removable with respect to the inner element and wherein the elongate elements extend from the first element towards the second element, further comprising a stationary feed tube arranged centrally with respect to the first element and the second element;

- providing between the feed tube and the inner element a rotatable coupling tube that is coupled to the feed tube to form a cartridge unit that is exchangeable from the separator;

- removing the outer element with respect to the inner element;

- uncoupling the cartridge unit from the inner element;

- removing the cartridge unit from the separator;

- exchanging the cartridge unit.

12. Cartridge unit for a centrifugal separator according to claim 1, wherein the cartridge unit comprises at least the feed tube and the coupling tube, preferably also comprising an outlet unit of the separator.

13. Cartridge unit according to claim 12, wherein the cartridge unit is provided with connection elements for connecting the cartridge unit to the inner element, such that in use, the couphng tube rotates with the inner element and the feed tube is stationary.