Patent Description:
A high speed centrifugal separator may be configured for separating a sludge phase from a liquid mixture. The sludge phase may have a solid matter content. The separator bowl of such a centrifugal separator may be provided with nozzles for discharging the sludge phase. The nozzles are arranged at an outer periphery of the separator bowl.

If the sludge phase contains erosive or abrasive solid matter, the separator bowl outer surface may be subjected to wear at the nozzles. Restoring a worn separator bowl is a costly operation. Accordingly, the separator bowl may be protected by exchangeable wear protection members.

<CIT> discloses a centrifugal a separator, comprising a centrifugal basket/bowl that has a basket shell provided with solids discharge nozzles. A wear protection system including wear protection elements protects the outer surface of the centrifugal basket. One wear protection element is mounted on the basket shell adjacent to each solids discharge nozzle. The wear protection element is fastened to the basket shell by means of screws and mutually corresponding groove and tongue elements between the basket shell and the wear protection element. The groove of the groove and tongue element is slanted from a groove start at an outer periphery of the basket shell at a distance from the solids discharge nozzle downwardly into the basket shell towards the solids discharge nozzle. XP055829834 discloses an example of an erosion liner.

It has been realised that the wear protection system of the centrifugal separator of <CIT> has several disadvantages such as, if the screws holding the wear protection element should be worn down, come loose, or are not mounted, the wear protection element will be thrown out of the groove, which may cause excessive damage to the centrifugal separator. Namely, the direction of the groove, slanting from the nozzle outwardly towards the outer periphery of the separator bowl, promotes propelling of the wear protection element outwardly from the separator bowl if the screws do not hold the wear protection element in place. Accordingly, the screws are an essential part of the wear protection system of <CIT>.

It would be advantageous to achieve a centrifugal separator overcoming, or at least alleviating, at least some of the above-mentioned drawbacks. In particular, it would be desirable to enable a centrifugal separator comprising wear protection members being less dependent on screws for securing the wear protection members. To better address one or more of these concerns, a centrifugal separator having the features defined in independent claim <NUM> and/or a protective member as defined in a further independent claim is provided.

According to an aspect of the invention, there is provided a centrifugal separator comprising a separator bowl delimiting therein a separation space and being configured to rotate about a rotational axis and nozzle members arranged peripherally at the separator bowl. Each nozzle member forms a nozzle outlet providing a passage from the separation space to a space outside the separator bowl, and the centrifugal separator comprises a protective member arranged downstream of each nozzle outlet at an outer periphery of the separator bowl. The nozzle member secures the protective member in relation to the separator bowl, at least in one circumferential direction of the separator bowl.

Since the nozzle member secures the protective member in relation to the separator bowl, at least in one circumferential direction of the separator bowl, screws to secure the protective member are either omitted or at least the use of fastening members, such as screws, is not the only means for securing the protective member.

The separator bowl forms a rotor of the centrifugal separator, which may be rotated at several thousand rotations per minute, rpm, during use of the centrifugal separator. Accordingly, the centrifugal separator may be a high speed centrifugal separator.

The separator bowl may be arranged inside a stationary housing of the centrifugal separator. The separator bowl may be driven to rotate about a vertical axis of rotation by a drive arrangement comprising e.g. an electric motor.

Inside the separation space, separation assisting members such as separation discs may be arranged. Accordingly, the centrifugal separator may be a disc stack centrifugal separator.

The centrifugal separator, during use thereof, is configured for separating a solid matter containing liquid feed mixture into at least a light phase and a sludge phase. The sludge phase is heavier than the light phase and is separated to a periphery of the separation space. The sludge phase is discharged from the separator bowl via the nozzle outlets into a portion of the stationary housing of the centrifugal separator.

The nozzle outlet of each nozzle member is arranged for continuous discharge of separated solid phase.

Each protective member provides wear protection of at least a portion of the outer surface of the separator bowl. As such, the protective member may have better wear resistance than the material of the body of the separator bowl. However, this is not a necessity since the protective members may be replaced when worn down. Accordingly, other and/or additional factors than wear resistance may also be considered in the choice of material, such as cost, available manufacturing methods, machining properties, etc..

The protective member may provide wear protection of the separator bowl not only directly circumferentially downstream of the nozzle outlet but may also protect part of the separator bowl above and below the nozzle outlet. Namely, the jet of separated sludge phase exiting the nozzle outlet may have a conical shape of e.g. up to <NUM> degrees from a centre axis of the nozzle outlet.

The nozzle outlet of each nozzle member is directed rearwardly in relation to a rotational direction of the separator bowl. That is, a jet of the sludge phase exiting the nozzle outlet during use of the centrifugal separator has at least one directional component extending in parallel to a tangent of the separator bowl, the directional component being directed in an opposite direction to the rotational direction of the separator bowl. Accordingly, downstream of a nozzle outlet is a position behind the nozzle outlet seen along a rotational direction of the separator bowl.

Herein, axial, radial, circumferential, and rotational directions relate to the separator bowl. An axial direction extends in parallel with a rotational axis of the separator bowl and a radial direction extends perpendicularly to the rotational axis. Circumferential and rotational directions extend around the rotational axis.

According to embodiments, the nozzle member may adjoin the protective member and/or may at least partially extends through the protective member in a radial direction of the separator bowl. In this manner, the protective member may be secured by the nozzle member in or at the separator bowl by the nozzle member, at least along a rotational direction of the separator bowl and, according to some embodiments, in a radial direction of the separator bowl.

According to embodiments, a surface of the protective member facing radially inwardly towards a body of the separator bowl is arranged at an angle (α) within a range of <NUM> - <NUM> degrees in relation to a tangent of the outer periphery of the separator bowl at the nozzle member, the angle (α) having its vertex at the nozzle member. In this manner, the protective member may be secured by the nozzle member in or at the separator bowl by the nozzle member. The angle (α) having its vertex at the nozzle member means that the vertex is positioned closer to the nozzle member than a broad end of the angle (α).

At an angle of <NUM> degrees, securing of the protective member by the nozzle member may be achieved along a rotational direction of the separator bowl.

At larger angles, the protective member may extend into the body of the separator bowl. Again, the nozzle member may secure the protective member along a rotational direction of the separator bowl. Additionally, the nozzle member may secure the protective member in a radial direction of the separator bowl. Namely, at larger angles, a related surface of the separator bowl opposite to the surface of the protective member facing towards the body of the separator bowl, comprises a directional component in the radial direction of the separator bowl. Thus, at larger angles, the nozzle member may prevent displacement of the protective member along the related surface and accordingly, along the radial direction of the separator bowl.

According to embodiments, the angle (α) may be within a range of <NUM> - <NUM> degrees in relation to the tangent of the outer periphery of the separator bowl, and the protective member may comprise a wedge-shaped body. A vertex end portion of the wedge-shaped body may be configured to be arranged at the nozzle member and an opposite wide end portion of the wedge-shaped body may be configured to be arranged at a distance from the nozzle member, In this manner, the protective member may be arranged to follow an outer contour of the body of the separator bowl and thus, may have an extension along the separator bowl suitable for protection against wear from a sludge phase exiting the separator bowl via the nozzle outlet during use of the centrifugal separator.

More specifically, in the range of ><NUM> - <NUM> degrees of the angle (α), such as <NUM> - <NUM> degrees, the separator bowl may be provided with a recess in which the protective member may be received. The wedge-shaped body of the protective member may be positioned in the recess.

Thus, with a corresponding angle of the wedge-shape of the protective member, the radially outer surface of the protective member may have an extension substantially along an outer surface of the separator bowl. Naturally, the radially outer surface of the wedge-shaped body of the protective member may be curved with the same radius as the outer surface of the separator bowl in the axial location of the nozzle member.

The vertex end portion of the wedge-shaped body being arranged at the nozzle member and the wide end portion of the wedge-shaped body being arranged at a distance from the nozzle member means that the vertex end portion is arranged closer to the nozzle member than the wide end portion.

According to embodiments, the protective member may be arranged in a slot extending from the nozzle member into the body of the separator bowl. In this manner, the protective member may be positioned in the separator bowl.

The slot forms a recess in the body of the separator bowl and may be sized such that the wedge-shaped body of the protective member fits into the slot and substantially fills the slot. According to a further aspect of the invention, there is provided a protective member for a centrifugal separator according to aspects and/or embodiments discussed herein, the protective member comprising a wedge-shaped body, a vertex end portion of the wedge-shaped body being configured to be arranged at the nozzle member, in that the outer contour of the vertex end portion has a radius adapted to be a radius of said nozzle member, and an opposite wide end portion of the wedge-shaped body being configured to be arranged at a distance from the nozzle member.

Since the vertex end portion of the wedge-shaped body is configured to be arranged at the nozzle member and the wide end portion of the wedge-shaped body is configured to be arranged at a distance from the nozzle member, the protective member is shaped such that, when mounted in the separator bowl of the centrifugal separator, the nozzle member secures the protective member in relation to the separator bowl. Thus, screws to secure the protective member can be omitted.

According to a further embodiment,, there is provided a protective member for a centrifugal separator according to aspects and/or embodiments discussed herein, the protective member comprising a sheet arranged along an outer periphery of the separator bowl.

Such a protective member in the form of a sheet may be utilised in embodiments of the centrifugal separator wherein the surface of the protective member facing towards the body of the separator bowl is arranged at an angle (α) of <NUM> degrees in relation to a tangent of an outer periphery of the separator bowl.

Further features of, and advantages with, the invention will become apparent when studying the appended claims and the following detailed description.

Various aspects and/or embodiments of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:.

Aspects and/or embodiments of the invention will now be described more fully.

<FIG> schematically illustrates a cross section through a centrifugal separator <NUM> according to embodiments. The centrifugal separator <NUM> is a high speed separator provided with nozzle outlets for a separated sludge phase from a separator bowl <NUM> of the centrifugal separator. The centrifugal separator <NUM> may be any such separator, the basic features of which will be described with reference to <FIG>.

Accordingly, the centrifugal separator <NUM> comprises a separator bowl <NUM> being configured to rotate about a rotational axis <NUM>. The separator bowl <NUM> is mounted on a spindle <NUM>. The spindle <NUM> is supported in a stationary housing <NUM> of the centrifugal separator <NUM>, e.g. via two bearings. A drive arrangement is configured to rotate the spindle <NUM> and the separator bowl <NUM> about the rotational axis <NUM>.

In the illustrated embodiments, the spindle <NUM> forms part of the drive arrangement. The drive arrangement comprises an electric motor and a rotor of the electric motor forms part of the spindle <NUM>. In alternative embodiments, the drive arrangement may instead be connected to the spindle <NUM>. Such alternative embodiments may comprise an electric motor connected via a transmission, e.g. comprising cog wheels or a belt drive, to the spindle <NUM>.

The separator bowl <NUM> delimits therein a separation space <NUM>. In the separation space <NUM> there may be arranged a separation aid configured to improve separation of liquid mixture. The separation aid, schematically indicated in the illustrated embodiments, comprises a stack of frusto-conical separation discs <NUM>. The separation discs <NUM> provide for an efficient separation of the liquid mixture into at least a light phase and a sludge phase during use of the centrifugal separator <NUM>. The stack of frusto-conical separation discs <NUM> is fitted coaxially with the rotational axis <NUM>.

The centrifugal separator <NUM> further comprises an inlet <NUM> for the liquid mixture and a light phase outlet <NUM> for the separated light phase. In the illustrated embodiments the inlet <NUM> and the light phase outlet <NUM> are arranged at an upper end of the separator bowl <NUM>. One or both of the inlet <NUM> and the light phase outlet <NUM> may alternatively be arranged at a lower end of the separator bowl <NUM>.

A number of nozzle members <NUM> for discharging the separated sludge phase from the separation space <NUM> and the separator bowl <NUM> are arranged at a periphery of the separator bowl <NUM>. The number of nozzle members <NUM> may be, e.g. <NUM> - <NUM>.

The housing <NUM> may comprise a number of individual parts and thus, may be assembled from several parts. In particular, the housing <NUM> may comprise a hood <NUM> enclosing the separator bowl <NUM>. From the nozzle members <NUM>, the sludge phase is discharged into a space <NUM> outside the separator bowl <NUM>. The space <NUM> is formed between the bowl <NUM> and the hood <NUM>. The sludge phase is lead out from the space <NUM> via a non-shown sludge outlet.

During use of the centrifugal separator <NUM> the separator bowl <NUM> is rotated at high speed, such as several thousands of rpm, and a solid matter containing liquid mixture is conducted via the inlet <NUM> to the centre of the separator bowl <NUM> and from there into the separation space <NUM>. The solid matter takes the form of small particles suspended in the liquid mixture. The liquid mixture may comprise one or more liquids. That is, in addition to the solid matter and a first liquid, the liquid mixture may comprise a further liquid of higher density than the first liquid. The liquid mixture is separated into the light phase and the sludge phase in the stack of frusto-conical separation discs <NUM>. The light phase is a liquid substantially free of any solid matter and the sludge phase is a solid matter containing liquid.

The separated light phase flows radially inwardly between the separation discs <NUM> towards the vertical axis <NUM> of rotation and out of the separator bowl <NUM> via the light phase outlet <NUM>. The separated solid matter is transported radially outwardly between the separation discs <NUM> towards a periphery of the separation space <NUM>. The solid matter flows out of the separator bowl <NUM> as a part of the sludge phase via the nozzle members <NUM> arranged at the periphery of the separator bowl <NUM>. In addition to the solid matter, the sludge phase may include one or more of the light phase and/or a separated heavy liquid phase. The nozzle members <NUM> form an open passage from the separation space <NUM> to the space <NUM> outside the bowl <NUM>.

If the solid matter has abrasive properties, the sludge phase may subject an outer surface of the separator bowl <NUM> to wear adjacent to the nozzle members <NUM>. Thus, the centrifugal separator <NUM> comprises wear protection measures, which now will be discussed with reference to <FIG>.

<FIG> and <FIG> illustrate partial views of a separator bowl <NUM>, such as a separator bowl <NUM> of the centrifugal separator <NUM> discussed above with reference to <FIG>. <FIG> illustrates a cross section through a portion of the separator bowl <NUM> along line IIb - Ilb in <FIG>.

The separator bowl <NUM> is provided with peripherally arranged nozzle members <NUM>. In <FIG> one of the nozzle members <NUM> is shown. The nozzle member <NUM> forms a nozzle outlet <NUM> providing a passage <NUM> from the separation space <NUM> to a space <NUM> outside the separator bowl <NUM>. The passage <NUM> is always open. That is, the nozzle member <NUM>, the nozzle outlet <NUM> and the passage <NUM> are arranged for continuous discharge of solid phase.

The invention is not limited to any particular kind of nozzle member. In these embodiments, the nozzle member <NUM> comprises two main portions, an inner portion <NUM> and an outer portion <NUM>. The outer portion <NUM> includes a radially outer portion of the passage <NUM> and the nozzle outlet <NUM> and may be made from a wear resistant material, such as a carbide or tungsten. The outer portion <NUM> may be exchangeable from an outside of the separator bowl <NUM> and may be fastened via e.g. a bayonet coupling to the inner portion <NUM>. Alternatively, the nozzle member may comprise only one part or more than two parts. For instance, nozzle member may comprise only one part or more than two parts. For instance, the nozzle outlet <NUM> may be provided in a separate exchangeable part, which may be fitted in the outer portion <NUM> of the nozzle member <NUM> shown in the illustrated embodiments or in a different kind of nozzle member.

A protective member <NUM> is arranged downstream of each nozzle outlet <NUM> at an outer periphery of the separator bowl <NUM>.

In <FIG>, the rotational direction of the separator bowl is indicated with a broad arrow. The nozzle outlet <NUM> of each nozzle member <NUM> is directed rearwardly in relation to the rotational direction of the separator bowl <NUM>. Downstream the nozzle outlet <NUM> is thus, behind the nozzle outlet <NUM> seen along the rotational direction of the separator bowl <NUM>. The nozzle outlet <NUM> may be directed rearwardly at a right angle to a radial direction of the separator bowl <NUM> or at an acute angle to the radial direction as shown in <FIG>. Accordingly, the jet of the sludge phase discharged through the nozzle outlet <NUM> has at least one directional component extending in parallel to a tangent of the separator bowl <NUM>.

The protective member <NUM> is arranged on the separator bowl <NUM> to protect the outer surface of the separator bowl <NUM> against wear from abrasive sludge phase discharged from the nozzle outlet <NUM>. The protective member <NUM> is exchangeable. Accordingly, if worn, the protective member <NUM> may be exchanged for an unworn protective member <NUM>. The body of the separator bowl <NUM> does not wear or at least does wear to a considerably lesser degree than if it were not provided with the protective member <NUM>.

The nozzle member <NUM> secures the protective member <NUM> in relation to the separator bowl <NUM>.

<FIG> shows the protective member <NUM> being about to be positioned in its dedicated position at the outer periphery of the separator bowl <NUM>.

Mounting of a new protective member <NUM> is performed by positioning it in its dedicated position at the outer periphery of the separator bowl <NUM> while the nozzle member <NUM>, or at least part thereof such as the outer portion <NUM>, is removed from the separator bowl <NUM>. In <FIG> the protective member <NUM> is partially positioned, still covering the opening <NUM> (indicated with a broken line) in the separator bowl <NUM>, into which the outer portion <NUM> of the nozzle member <NUM> fits. Once the protective member <NUM> is in position, the nozzle member <NUM> is mounted in the separator bowl <NUM>, such as the outer portion <NUM> of the nozzle member <NUM> being mounted in its inner portion <NUM>. The nozzle member <NUM> prevents the protective member <NUM> from coming loose from the separator bowl <NUM>.

In embodiments, wherein the nozzle member <NUM> comprises the inner portion <NUM> and the outer portion <NUM>, as in the illustrated embodiments, the outer portion <NUM> of the protective member <NUM> secures the protective member <NUM> in relation to the separator bowl <NUM>.

In some embodiments, such as the embodiments illustrated in <FIG>, there is no additional member required for securing the protective member <NUM> to the separator bowl <NUM>.

The nozzle member <NUM> adjoins the protective member <NUM>. Thus, the nozzle member <NUM> prevents the protective member <NUM> from moving beyond the nozzle member <NUM> and secures the protective member <NUM> to the separator bowl <NUM>. The nozzle member <NUM> may be arranged in adjoining abutment with the protective member <NUM> to ensure secure positioning of the protective member <NUM>.

According to some embodiments, such as those illustrated in <FIG>, a surface <NUM> of the protective member <NUM> facing radially inwardly towards a body <NUM> of the separator bowl <NUM> is arranged at an angle α within a range of <NUM> - <NUM> degrees in relation to a tangent of the outer periphery of the separator bowl <NUM> at the nozzle member <NUM>. The angle α has its vertex at the nozzle member <NUM>. Accordingly, the protective member <NUM> extends into the body <NUM> of the separator bowl <NUM>.

A related surface <NUM> of the body <NUM> of the separator bowl <NUM>, opposite to the surface <NUM> of the protective member <NUM> facing towards the body <NUM> of the separator bowl <NUM>, comprises a directional component along a radial direction of the separator bowl <NUM>. Thus, in these embodiments, the nozzle member <NUM> secures the protective member <NUM> along a rotational direction of the separator bowl <NUM> as well as along the radial direction of the separator bowl <NUM>. Put differently, the nozzle member <NUM> prevents displacement of the protective member <NUM> along the related surface <NUM> of the separator bowl <NUM>.

The protective member <NUM> is arranged in a slot <NUM> extending from the nozzle member <NUM> into the body <NUM> of the separator bowl <NUM>. The protective member <NUM> positioned in the slot <NUM> is thus, arranged in the body <NUM> of the separator bowl <NUM>.

The related surface <NUM> of the body <NUM> of the separator bowl <NUM> forms a radially inner surface of the slot <NUM>.

According to these embodiments, the protective member <NUM> comprises a wedge-shaped body <NUM>. A vertex end portion <NUM> of the wedge-shaped body <NUM> is configured to be arranged at the nozzle member <NUM> and an opposite wide end portion <NUM> of the wedge-shaped body <NUM> is configured to be arranged at a distance from the nozzle member <NUM>. The protective member <NUM> is thus, devised to widen in a direction downstream of the nozzle outlet <NUM>. The wedge-shaped body <NUM> may have a curved outer surface to generally follow the outer radius of the separator bowl <NUM>.

The wedge-shaped body <NUM> of the protective member <NUM> may comprises at least one lateral projection <NUM> and the body <NUM> of the separator bowl <NUM> may be provided with at least one groove <NUM> extending substantially perpendicularly to the slot <NUM>. The at least one lateral projection <NUM> engages with the at least one groove <NUM>. In this manner, the at least one lateral projection <NUM> engaging with the at least one groove <NUM> contributes to securing the protective member <NUM> to the separator bowl <NUM> in the slot <NUM>.

In <FIG> it is shown how the lateral projection <NUM> extending around part of the body <NUM> of the protective member <NUM> is inserted and slid into the groove <NUM> extending around the perimeter of the slot <NUM>.

The nozzle outlet <NUM> may be arranged inside the outer periphery of the separator bowl <NUM>. In this manner, the nozzle member <NUM> may be arranged, at least to a large extent, within the outer periphery of the separator bowl <NUM>. Thus, it is avoided that the nozzle member <NUM> causes noise during high speed rotation of the separator bowl <NUM>. Such noise would occur if the nozzle member <NUM> extends beyond the outer periphery of the separator bowl <NUM> to a certain extent.

<FIG> illustrate a protective member <NUM> according to embodiments. The protective member <NUM> may be a protective member <NUM> as discussed above with reference to <FIG>.

The protective member <NUM> is provided for a centrifugal separator according to aspects and/or embodiments discussed herein. The protective member <NUM> comprising a wedge-shaped body <NUM>. A vertex end portion <NUM> of the wedge-shaped body <NUM> is configured to be arranged at a nozzle member of a separator bowl of the centrifugal separator. An opposite wide end portion <NUM> of the wedge-shaped body <NUM> is configured to be arranged at a distance from the nozzle member.

More specifically, the vertex end portion <NUM> of the wedge-shaped body <NUM> has an outer contour, which is shaped such that it is configured to border to the nozzle member. In the illustrated embodiments, the outer contour has a radius R adapted to a radius of the relevant nozzle member. Accordingly, the vertex end portion <NUM> of the wedge-shaped body <NUM> may be arranged in adjoining abutment with the nozzle member.

The opposite wide end portion <NUM> of the wedge-shaped body <NUM> is configured to be arranged at a distance from the nozzle member firstly, due to the fact that it is arranged opposite to the vertex end portion <NUM>. Secondly, the opposite wide end portion <NUM> may be shaped such that it fits into a slot in the separator bowl. In the illustrated embodiments, the opposite wide end portion <NUM> has an outer contour adapted to an inner end portion of the slot in the separator bowl. For instance, the wide end portion <NUM> of the wedge-shaped body <NUM> may have a rounded outer contour perpendicular to the wedge-shape.

The wedge-shaped body <NUM> may comprise at least one lateral projection <NUM>. In this manner, the at least one projection <NUM> may engage with a corresponding groove in a body of the separator bowl. Thus, the protective member <NUM> may be devised for being held by the at least one lateral projection <NUM> in the separator bowl, as discussed above inter alia with reference to <FIG>.

The wedge-shaped body <NUM> of the protective member <NUM> may comprise a surface portion <NUM> extending perpendicularly to the at least one lateral projection <NUM>. A relief surface <NUM> may be arranged between the at least one lateral projection <NUM> and the surface portion <NUM> extending perpendicularly to the at least one lateral projection <NUM>. In this manner, manufacturing of the protective member <NUM> may be facilitated. Namely, by providing the relief surface <NUM> between the lateral projection <NUM> and the surface portion <NUM> extending perpendicularly to the lateral projection <NUM>, the surface portion <NUM> may be shaped without a transition between the lateral projection <NUM> and the surface portion <NUM> impeding such shaping.

The relief surface <NUM> forms part of a recess into the body <NUM> of the protective member <NUM> between the at least one lateral projection <NUM> and the surface portion <NUM>.

The wedge-shaped body <NUM> of the protective member <NUM> may be produced by additive manufacturing. In this manner, a complex shape of the protective member <NUM> may be produced. Moreover, the protective member <NUM> may be manufactured from wear resistant materials, which may be difficult to subject to machining.

The final tolerances of e.g. the lateral projection <NUM> and the surface portion <NUM> may be achieved after additive manufacturing, e.g. by grinding.

Alternatively, the wedge-shaped body <NUM> of the protective member <NUM> may be produced by any other suitable manufacturing method, such as casting, machining, etc..

<FIG> illustrate partial views of a separator bowl <NUM>, such as a separator bowl <NUM> of the centrifugal separator <NUM> discussed above with reference to <FIG>. <FIG> shows a front view and <FIG> shows a side view of the separator bowl <NUM> along line IVb - Ivb in <FIG>.

Again, the separator bowl <NUM> is provided with peripherally arranged nozzle members <NUM>. Each nozzle member <NUM> forms a nozzle outlet <NUM> providing a passage from the separation space inside the separation bowl <NUM> to a space outside the separator bowl <NUM>. A protective member <NUM> (marked with hatchings) is arranged downstream of each nozzle outlet <NUM> at an outer periphery of the separator bowl <NUM>.

In <FIG> an opening <NUM> in the separator bowl <NUM>, into which at least part of the nozzle member <NUM> fits is shown. A corresponding opening <NUM> for the nozzle member <NUM> is provided in the protective member <NUM>. In <FIG>, the nozzle member <NUM> is shown mounted in the separator bowl <NUM>.

According to these embodiments, the protective member <NUM> comprises a sheet <NUM> arranged along the outer periphery of the separator bowl <NUM>. The sheet <NUM> protects the outer surface of the separator bowl <NUM> against wear. The sheet <NUM> may be a sheet metal with good abrasive properties.

Accordingly, a surface <NUM> of the protective member <NUM> facing radially inwardly towards a body <NUM> of the separator bowl <NUM> is arranged at an angle of <NUM> degrees in relation to a tangent of the outer periphery of the separator bowl <NUM> at the nozzle member <NUM>.

Again, the nozzle member <NUM> secures the protective member <NUM> in relation to the separator bowl <NUM>. In these embodiments, the nozzle member <NUM> secures the protective member <NUM> in the circumferential direction of the separator bowl <NUM>, i.e. along a rotational direction of the separator bowl <NUM>. This is achieved by the nozzle member <NUM> at least partially extending through the protective member <NUM> in a radial direction of the separator bowl <NUM>.

Once the protective member <NUM> is in position, the nozzle member <NUM> is mounted in the separator bowl <NUM>, such as the outer portion <NUM> of the nozzle member <NUM> being mounted in its inner portion <NUM>.

More specifically, first the protective member <NUM> is positioned on the outer periphery of the separator bowl <NUM> and then the nozzle member <NUM>, such as an outer portion <NUM> of the nozzle member <NUM>, is mounted in the separator bowl <NUM>. The nozzle member <NUM>, when mounted in the opening <NUM> of the separator bowl <NUM> extends at least partially through the opening <NUM> provided through the sheet <NUM> of the protective member <NUM>. Thus, the nozzle member <NUM> secures the protective member <NUM> in the circumferential direction of the separator bowl <NUM>.

Again, it may be the outer portion <NUM> of the protective member <NUM> that secures the protective member <NUM> in relation to the separator bowl <NUM>.

According to some embodiments, the nozzle member may be at least partially secured in a radial direction of the separator bowl by the protective member. For instance, the nozzle member may engage with the protective member via a bayonet coupling. Since the nozzle member extends into the body of the separator bowl, radially inside the protective member, also in such embodiments, the nozzle member secures the protective member in a circumferential direction of the separator bowl.

The nozzle outlet <NUM> is arranged outside the outer periphery of the separator bowl <NUM> and radially outside the protective member <NUM>. In this manner, the nozzle outlet <NUM> is positioned for unimpeded ejection of the sludge phase through the nozzle outlet <NUM> into the space outside the separator bowl <NUM>.

The protective member <NUM> is secured in a radial direction of the separator bowl <NUM> with at least two fastening elements <NUM> at the outer periphery of the separator bowl <NUM>. In this manner, the protective member <NUM> is held in position at the outer periphery of the separator bowl <NUM> together with the nozzle member <NUM>, in radial and circumferential directions.

In these embodiments, the at least two fastening elements <NUM> comprise two rails attached to the outer periphery of the separator bowl <NUM> axially above and below the opening <NUM> for the nozzle member <NUM>. The protective member <NUM> is slid under the two rails. Thus, the securing in the radial direction of the protective member <NUM> is achieved.

The protective member <NUM> extends outside the nozzle member <NUM> in an axial direction of the separator bowl <NUM>. In this manner, a broad area of the outer surface of the separator bowl <NUM>, in the axial direction, may be protected by the protective member <NUM>. This may be advantageous if the nozzle outlet <NUM> is worn to such a degree that the jet of the sludge phase ejected through the nozzle outlet <NUM> has a wide spray angle.

<FIG> illustrates embodiments of a protective member <NUM>. The protective member <NUM> resembles in much the protective member <NUM> discussed above with reference to <FIG>.

Again, the protective member <NUM> comprises a sheet <NUM>. The sheet <NUM> of the protective member <NUM> is configured to be arranged along the outer periphery of a separator bowl.

Again, the nozzle member (not shown) secures the protective member <NUM> in the circumferential direction of the separator bowl. Again, the protective member <NUM> is secured in the radial direction of the separator bowl with at least two fastening elements at the outer periphery of the separator bowl <NUM>.

In these embodiments, the at least two fastening elements comprise a number of screws (not shown), which extended through holes <NUM> provided in the sheet <NUM>. Although in these embodiments, screws are relied upon to secure the protective member <NUM> in a radial direction of the separator bowl, the protective member <NUM> is secured in a circumferential direction by the nozzle member extending through the opening <NUM> in the sheet <NUM>.

<FIG> illustrate a separator bowl <NUM> and a protective member <NUM> according to embodiments. <FIG> illustrates a partial view of the separator bowl <NUM>, such as a separator bowl <NUM> of the centrifugal separator <NUM> discussed above with reference to <FIG>. <FIG> illustrates a cross section through a portion of the separator bowl <NUM> along line VIb - VIb in <FIG> illustrate two perspective views of the protective member <NUM>. The protective member <NUM> of these embodiments resembles in much the protective member <NUM> according to the embodiments discussed above with reference to <FIG>. Also, the manner in which the protective member <NUM> is connected to the separator bowl <NUM> resembles in much the manner discussed above with reference to <FIG>. Accordingly, in the following, mainly the differences between these embodiments and those of <FIG> will be discussed.

Again, the separator bowl <NUM> is provided with peripherally arranged nozzle members <NUM>. In <FIG> an outer portion <NUM> of the nozzle members <NUM> is shown. The nozzle member <NUM> forms a nozzle outlet <NUM> providing a passage <NUM>. A protective member <NUM> is arranged downstream of each nozzle outlet <NUM> at an outer periphery of the separator bowl <NUM>.

Again, the nozzle member <NUM> secures the protective member <NUM> in relation to the separator bowl <NUM>. There is no additional member required for securing the protective member <NUM> to the separator bowl <NUM>.

The nozzle member <NUM> extends partially trough the protective member <NUM>. An opening <NUM> is provided in the protective member <NUM> through which part of the nozzle member <NUM> extends. Thus, the nozzle member <NUM> prevents the protective member <NUM> from moving in a circumferential direction of the separator bowl <NUM>.

Moreover, the body <NUM> of the separator bowl <NUM> is provided with a slot <NUM> extending around the nozzle member <NUM>. The protective member <NUM> is positioned in the slot <NUM>.

A body <NUM> of the protective member <NUM> comprises two protrusions <NUM>, <NUM>. The slot <NUM> comprises two recesses <NUM>, <NUM>. Each of the two protrusions <NUM>, <NUM> has a form mating with a respective shape of the two recesses <NUM>, <NUM>.

The body <NUM> of the protective member <NUM>, more specifically, each of the two protrusions <NUM>, <NUM> comprises a lateral projection <NUM>. The body <NUM> of the separator bowl <NUM>, in each of the recesses <NUM>, <NUM>, is provided with a groove <NUM> extending substantially perpendicularly to the slot <NUM>. The lateral projections <NUM> engage with the grooves <NUM>. This engagement between the projections <NUM> and the grooves <NUM> contributes to securing the protective member <NUM> to the separator bowl <NUM> in the slot <NUM>.

Again, a surface <NUM> of the protective member <NUM> facing radially inwardly towards the body <NUM> of the separator bowl <NUM> is arranged at an angle α within a range of <NUM> - <NUM> degrees in relation to a tangent of the outer periphery of the separator bowl <NUM> at the nozzle member <NUM>. The angle α has its vertex at the nozzle member <NUM>, i.e. in a region of the nozzle member <NUM>. The surface <NUM> may be a surface of one of the protrusions <NUM>, <NUM>.

A related surface <NUM> of the body <NUM> of the separator bowl <NUM>, opposite to the surface <NUM> of the protective member <NUM> facing towards the body <NUM> of the separator bowl <NUM>, comprises a directional component along a radial direction of the separator bowl <NUM>. Thus, the nozzle member <NUM> secures the protective member <NUM> along a rotational direction of the separator bowl <NUM> as well as along the radial direction of the separator bowl <NUM>.

Again, the nozzle outlet <NUM> is arranged inside the outer periphery of the separator bowl <NUM>.

The protective member <NUM> extends outside the nozzle member <NUM> in an axial direction of the separator bowl <NUM>. In this manner, a broad area of the outer surface of the separator bowl <NUM>, in the axial direction, may be protected against wear by the protective member <NUM>. This may be advantageous if the nozzle outlet <NUM> is worn to such a degree that the jet of the sludge phase ejected through the nozzle outlet <NUM> has a wide spray angle.

Claim 1:
A centrifugal separator (<NUM>) comprising a separator bowl (<NUM>) delimiting therein a separation space (<NUM>) and being configured to rotate about a rotational axis (<NUM>) and
nozzle members (<NUM>) arranged peripherally at the separator bowl (<NUM>), wherein
each nozzle member (<NUM>) forms a nozzle outlet (<NUM>) providing a passage (<NUM>) from the separation space (<NUM>) to a space (<NUM>) outside the separator bowl (<NUM>), and wherein
the centrifugal separator (<NUM>) comprises a protective member (<NUM>) arranged downstream of each nozzle outlet (<NUM>) at an outer periphery of the separator bowl (<NUM>),
characterised in that
the nozzle member (<NUM>) secures the protective member (<NUM>) in relation to the separator bowl (<NUM>), at least in one circumferential direction of the separator bowl (<NUM>).