阅读说明：本技术 用于离心分离器的分离盘 (Separating disc for a centrifugal separator ) 是由 K.希尔丁 S-A.尼尔松 P.索尔维德 于 2018-04-30 设计创作，主要内容包括：本发明提供了一种用于离心分离器的分离盘(1),所述盘适于被包括在离心转子的内部的分离盘的叠堆中以用于分离流体混合物。分离盘(1)具有带有内表面(2)和外表面(3)的截顶圆锥形状和从内表面和外表面中的至少一个延伸的多个间隔部件(4)。斑点形式的间隔部件(4)用于在分离盘的叠堆中的相互邻近的分离盘之间提供间隙。分离盘(1)进一步包括至少一个伸长肋(36),其从内表面延伸至高度(h),高度(h)小于所述多个间隔部件所延伸至的高度(H)。此外,至少一个伸长肋(36)从内表面(2)上的第一位置延伸至内表面上的第二位置,其中第二位置位于比第一位置的径向距离更大的径向距离处,并且伸长肋的高度(h)与间隔部件的高度(H)之间的关系为h/H>0.7。(The invention provides a separation disc (1) for a centrifugal separator, which disc is adapted to be included in a stack of separation discs inside a centrifugal rotor for separating a fluid mixture. The separation disc (1) has a truncated conical shape with an inner surface (2) and an outer surface (3) and a plurality of spacing members (4) extending from at least one of the inner and outer surfaces. The spacing members (4) in the form of spots are intended to provide interspaces between mutually adjacent separation discs in the stack of separation discs. The separation disc (1) further comprises at least one elongated rib (36) extending from the inner surface to a height (H) which is smaller than the height (H) to which the plurality of distance members extend. Furthermore, at least one elongated rib (36) extends from a first position on the inner surface (2) to a second position on the inner surface, wherein the second position is located at a radial distance greater than the radial distance of the first position, and the relationship between the height (H) of the elongated rib and the height (H) of the spacer member is H/H > 0.7.)

1. A separation disc for a centrifugal separator, the disc being adapted to be included in a stack of separation discs inside a centrifugal rotor for separating a fluid mixture, wherein the separation disc has a truncated conical shape with an inner surface and an outer surface and a plurality of spacing members extending a height (H) from at least one of the inner surface and the outer surface, wherein

The plurality of spacing members are intended to provide interspaces between mutually adjacent separation discs in the stack of separation discs, and

Wherein the separation disc further comprises at least one elongated rib extending from the inner surface to a height (H) which is smaller than the height (H) to which the plurality of spacing members extend, and

Wherein the at least one elongated rib extends from a first location on the inner surface to a second location on the inner surface, wherein the second location is at a greater radial distance than the radial distance of the first location, and

Wherein a relationship between the height (H) of the elongated rib and the height (H) of the spacer member is H/H.gtoreq.0.7.

2. The separation disc according to claim 1, wherein the relationship between the height (H) of the elongated ribs and the height (H) of the spacing members is 0.75 ≦ H/H ≦ 0.95 or 0.80 ≦ H/H ≦ 0.90.

3. The separation disc according to claim 1 or 2, wherein the spacing members also extend from the inner surface.

4. The separation disc according to any one of the preceding claims, wherein the separation disc comprises at least four elongated ribs.

5. the separation disc according to any one of the preceding claims, wherein the at least one elongated rib is straight and extends in a radial direction.

6. The separation disc according to any one of claims 1-4, wherein the at least one elongated rib is curved.

7. The separation disc according to any one of the preceding claims, wherein the at least one elongated rib extends over more than 50% of the length of the radial extension of the inner surface of the disc.

8. The separation disc according to claim 7, wherein the at least one elongated rib extends radially along substantially the entire radial extension of the inner surface of the disc.

9. The separation disc according to any one of the preceding claims, wherein the at least one elongated rib has a width at the surface of the separation disc below 2 mm.

10. The separation disc according to any one of the preceding claims, wherein the spacing member and the at least one elongated rib are integrally formed in one piece with the material of the separation disc.

11. The separation disc according to any one of the preceding claims, wherein the at least one elongated rib is wider at the surface than at a portion at the height (h) to which the elongated rib extends, as seen in a cross-section perpendicular to the direction in which the elongated rib extends on the surface.

12. The separation disc according to any one of the preceding claims, wherein the plurality of spacing members comprises a plurality of spacing members in the form of spots.

13. The separation disc according to claim 12, wherein the spot-form spacing members have a tip-shaped cross-section.

14. A stack of separation discs adapted to be included in the interior of a centrifugal rotor for separating a liquid mixture, comprising axially aligned separation discs having a truncated conical shape with an inner surface and an outer surface,

And wherein the axially aligned separation discs comprise a plurality of discs according to any of claims 1-13 having spacing members and at least one elongated rib, the discs being arranged such that the elongated rib on a separation disc is not in contact with an adjacent separation disc.

15. A centrifugal separator for separating at least two components of a fluid mixture having different densities, the centrifugal separator comprising:

A fixed frame, a movable frame and a movable frame,

a main shaft rotatably supported by the frame,

A centrifuge rotor mounted to a first end of the main shaft for rotation therewith about a rotation axis (X), wherein the centrifuge rotor comprises a rotor housing enclosing a separation space in which a stack of separation discs is arranged to rotate coaxially with the centrifuge rotor,

A separator inlet extending into the separation space for supplying the fluid mixture to be separated,

a first separator outlet for discharging a first separated phase from the separation space,

A second separator outlet for discharging a second separated phase from the separation space;

wherein the stack of separation discs is as according to claim 14.

Technical Field

the present invention relates to the field of centrifugal separation, and more particularly to a centrifugal separator comprising separation discs.

Background

Centrifugal separators are generally used to separate liquids and/or solids from a liquid or gas mixture. During operation, the fluid mixture to be separated is introduced into a rotating bowl (bowl), and due to centrifugal forces, heavy particles or denser liquids (such as water) accumulate at the periphery of the rotating bowl, while less dense liquids accumulate closer to the central axis of rotation. This allows for example to collect the separated components by means of different outlets arranged at the periphery and close to the rotation axis, respectively.

The separation discs are stacked in the rotating drum at a mutual distance to form interspaces between themselves, thus forming surface-enlarging inserts in the drum. Metallic separation discs are used in combination with a relatively robust and large sized centrifugal separator for separating a liquid mixture, and the separation discs themselves are thus of relatively large size and exposed to both high centrifugal forces and high liquid forces. The liquid mixture to be separated in the centrifugal rotor is led through a gap in which the liquid mixture separates into phases of different densities during operation of the centrifugal separator. The interspaces are provided by spacing members arranged on the surface of the respective separation disc. There are many ways of forming such spacing means. These spacing members may be formed by attaching separate members in the form of narrow strips or small circles of sheet metal to the separation discs, typically by spot welding these members to the surface of the separation discs.

In order to maximize the separation capacity of the centrifugal separator, it is desirable to fit as many separation discs as possible into the stack within a given height in the separator. More separation discs in the stack means more interspaces in which the liquid mixture can be separated. However, since the separation discs are made thinner, the separation discs will show a loss of stiffness and irregularities in their shape may start to occur. Furthermore, the separation discs are compressed in a stack inside the centrifugal rotor to form a compact unit. The thin separation discs may thereby flex and/or due to their irregular shaping cause non-uniform-sized interspaces in the stack of separation discs. Thus, in certain parts of the interspaces (e.g. remote from the spacer member), mutually adjacent separation discs may be compressed completely against each other, leaving no interspaces at all. In other parts of the interspace, e.g. in the vicinity of the spacing members, the separation discs will not be deflected to a large extent and thus provide a sufficient height.

in WO2013020978 a disc comprising spot-shaped spacer members for reducing the risk of non-uniform sized gaps in the stack is disclosed. The disc in the present disclosure comprises spot-shaped spacing members having a spherical or cylindrical shape as seen in the direction of the height of the spot-shaped spacing members.

Furthermore, the flow of the phases in the gaps between the discs is very important. Thus, there is a need in the art for alternative designs for separation discs that facilitate the use of thin discs, which at the same time provide good flow of the phase between the discs during separation.

Disclosure of Invention

A primary object is to provide a separation disc that assists in guiding separated sludge along the surface of the disc during operation.

A further object of the invention is to provide a separation disc for a centrifugal separator which reduces the risk of non-uniform-sized interspaces in the stack.

A further object is to provide a disc which allows the use of thin separation discs in a disc stack.

Furthermore, it is an object to provide a disc stack and a centrifugal separator comprising such a separation disc.

As a first aspect of the invention a separation disc for a centrifugal separator is provided, the disc being adapted to be included in a stack of separation discs inside a centrifugal rotor for separating a fluid mixture, wherein the separation disc has a truncated conical shape with an inner surface and an outer surface and a plurality of spacing members extending a height (H) from at least one of the inner surface and the outer surface, wherein

A plurality of spacing members for providing interspaces between mutually adjacent separation discs in the stack of separation discs, an

Wherein the separation disc further comprises at least one elongated rib extending from the inner surface to a height (H) which is smaller than the height (H) to which the plurality of distance members extend, and

Wherein the at least one elongated rib extends from a first location on the inner surface to a second location on the inner surface, wherein the second location is at a greater radial distance than the radial distance of the first location, and

Wherein the relationship between the height (H) of the elongated rib and the height (H) of the spacer member is H/H > 0.7.

The separation discs may for example comprise metal or consist of a metallic material, such as stainless steel.

The separating discs may further comprise or consist of a plastic material.

The separating discs may be injection moulded.

The separation discs may further be adapted to be compressed in the stack of separation discs inside the centrifugal rotor for separating the liquid mixture.

A truncated conical shape refers to the shape of a truncated cone, i.e. the shape of a frustum with a cone, which is the shape of a cone with the narrow end or tip removed. The axis of the truncated conical shape thus defines the axial direction of the separation discs, which is the direction of the height of the corresponding conical shape or the direction of the axis through the apex of the corresponding conical shape.

Thus, the inner surface is the surface facing the axis of the truncated cone, while the outer surface is the surface facing away from the axis of the truncated cone. The spacer member may be provided only on the inner surface of the truncated cone shape, only at the outer surface of the truncated cone shape, or on both the inner and outer surfaces of the truncated cone shape.

Half of the opening angle of the frustoconical shape is generally defined as the "alpha (alpha) angle". As an example, the separation discs may have an alpha angle between 25 ° and 45 °, such as between 35 ° and 40 °.

The spacer member is the following on the surface of the disc: when two separation discs are stacked on top of each other, the spacing members space apart the two separation discs, i.e. define interspaces between the discs. The spacer member may be arranged on the disc such that the spacer member supports both the radially outer portion of the disc and the radially inner portion of the disc. In other words, the spacing members may be distributed over both the radially outer half of the surface of the disc and the radially inner half of the surface of the disc.

The height H of the spacer member is a height perpendicular to the surface.

The spacing members may extend from the surface of the separation disc to a height H of less than 0.8 mm. As an example, the spacing members may extend from the surface of the separation disc to a height of less than 0.60 (such as less than 0.50 mm, such as less than 0.40 mm, such as less than 0.30 mm, such as less than 0.25 mm, such as less than 0.20 mm).

The separation disc further comprises at least one elongated rib extending on the inner surface over a height H smaller than the height H of the spacing member.

Thus, the height of the elongated ribs is such that the elongated ribs do not form part of any spacing member, and the elongated ribs do not carry any weight in the stack of discs of separation discs, but are instead provided for the guiding means.

Thus, the elongated rib has a length greater than its width. The length may be in the radial direction. The elongate ribs may extend over the surface a distance (d) greater than a height (h) above the surface, such as greater than two times the height, such as greater than five times the height, such as greater than ten times the height.

The elongate ribs or strips have a length of more than 10 mm, such as more than 20 mm, such as more than 50mm, such as more than 100 mm.

Furthermore, the elongated rib extends radially outwardly, i.e. from a first position to a second position, wherein the second position is located radially outwardly of the first position. Thus, the separation disc may comprise a central opening and an outer periphery, and the elongated ribs may extend in a direction from the central opening towards the outer periphery.

The relation H/H is at least 0.7, which means that the height of the elongated ribs is at least 70% of the height of the spacer members. Thus, the height of the elongated ribs may be such that during operation of a centrifugal separator comprising a stack of such separation discs, the elongated ribs extend out into the ground flow between two adjacent separation discs, i.e. out of any form of Ekman layer at the surface of the separation discs.

In an embodiment of the first aspect of the invention, the relation between the height (H) of the elongated ribs and the height (H) of the spacer members is H/H ≧ 0.7. In embodiments of the first aspect of the invention, the relationship between the height (H) of the elongate ribs and the height (H) of the spacing members may be 0.75 ≦ H/H ≦ 0.95 (such as 0.80 ≦ H/H ≦ 0.90).

The thickness of the separation discs may be less than 0.60 mm (such as less than 0.50 mm, such as less than 0.45 mm, such as less than 0.40 mm, such as less than 0.35 mm, such as less than 0.30 mm).

furthermore, the separation discs may have a diameter of more than 200 mm (such as more than 300 mm, such as more than 350 mm, such as more than 400 mm, such as more than 450 mm, such as more than 500 mm, such as more than 530 mm).

The first aspect of the present invention is based on the following findings: the elongate strips do not have to carry any load in the compressed stack but may instead merely act as a guide mechanism. For example, in a compressed stack of separation discs, the separation is performed in the interspaces between two adjacent discs. The heavier phase (such as sludge) is transported along the surface of the upper disc (i.e., along the "ceiling" of the gap), while the separated less dense phase is transported along the surface of the lower disc (i.e., along the "floor" of the gap). Thus, where the elongated strips have a lower height than the spacing members and are disposed on the inner surface of the disc, these elongated strips will assist in guiding the sludge along the "ceiling" of the gap, but will not interfere with the phases being transported along the "floor" of the gap.

In an embodiment of the first aspect of the invention, the spacer member also extends from the inner surface.

Thus, both the spacing member and the elongated rib may extend from the inner surface, such as only from the inner surface.

In an embodiment of the first aspect of the invention, the separation disc comprises at least four elongated ribs.

As an example, the separation disc may comprise at least 8 (such as at least 12, such as at least 18) elongated ribs.

Furthermore, the separation disc may comprise 4-60 elongated ribs (such as 4-50, such as 8-40, such as 12-30 elongated ribs) on the inner surface.

The elongate ribs may be equally spaced around the circumference of the separation disc.

In an embodiment of the first aspect of the invention, the at least one elongated rib is straight and has an extension in the radial direction.

Thus, the radial direction is radially from the rotational axis (x) of the disc towards the outer perimeter (such as from the central opening of the separation disc towards the outer perimeter). The at least one elongated rib may extend in a straight radial direction or in a straight direction forming an angle with the radius of the separation disc. Thus, the straight elongated ribs may be arranged to guide the phases along a straight path on the surface of the separation discs. The elongate rib may have an extension primarily in a radial direction.

In an embodiment of the first aspect of the invention, the at least one elongate rib is curved. The extension of the curved rib may be primarily in the radial direction.

Thus, the at least one elongate rib may be curved. The curved elongated rib may be curved when viewed as a projection onto a plane perpendicular to the axis of rotation (X).

Thus, the ribs may extend along a curved path and form an angle with the generatrices of the separation discs at least at a radially outer circumferential portion of the separation discs. Due to the curved form of the elongated rib, the separated phases can also be guided by the elongated rib along a path that curves in a corresponding manner.

The radial length of the elongated ribs may be different on the disc, or all of the elongated ribs may have the same length. The radial length may be, for example, greater than 10% (such as greater than 25%) of the radial length of the disc (i.e., the length between the central opening and the outer perimeter).

In an embodiment of the first aspect of the invention, the at least one elongate rib extends for a length greater than 50% of the radial extension of the inner surface of the disc.

for example, the at least one elongate rib extends for a length greater than 75% of the radial extension of the inner surface of the disc.

The at least one elongated rib may extend radially along substantially the entire radial extension of the inner surface of the disc, which means that the rib may extend substantially across the entire conical portion of the separation disc and terminate in the vicinity of the radially outer circumferential edge of the separation disc.

In an embodiment of the first aspect of the invention, the at least one elongated rib has a width at the surface of the separation disc below 2 mm.

thus, the width of the at least one elongate rib may be less than 1.5 mm (such as less than 1 mm).

The elongated ribs may be in the form of narrow strips of sheet metal or separate pieces of circular stock, which are attached to the surface of the separation discs. Alternatively or additionally, the elongated ribs may also be formed integrally with the material of the separation discs.

In an embodiment of the first aspect of the invention, the spacing member and the at least one elongated rib are integrally formed in one piece with the material of the separation disc. For example, the spacing members and the elongate ribs may be integrally formed on the inner surface of the disc.

Thus, all the protrusions of the separation discs may be formed from the material of the separation discs themselves.

In an embodiment of the first aspect of the invention, at least one elongate rib is wider at the surface than at a portion at a height (h) to which the elongate rib extends, as seen in a cross-section perpendicular to the direction to which the elongate rib extends on the surface.

Thus, the elongate rib may form a ridge at the surface having a cross-section that tapers outwardly from the surface. The cross-section may be tip shaped. As an example, the cross-section of the tip shape may have a geometry that smoothly tapers from a flat base at the surface to the tip (i.e., the apex at a certain height above the base). The apex may be located directly above the centroid of the base. However, the apex may also be located at a point which is not above the centroid, so that the tip-shaped spacing member has the form of an oblique cone or an oblique pyramid. The "tip" of the cross-section of the tip shape may have a tip radius that is less than the height h. Thus, the tip may be rounded.

Furthermore, the portion at the height (h) to which the elongate rib extends may be flat, i.e. substantially parallel to the surface.

For the flow dynamics between the separation discs it may be advantageous to have elongated ribs that are wider at the surface and then become thinner as they extend from the surface. In other words, an elongated rib having such a shape may obstruct the fluid flow between the separation discs to a lesser extent, if compared to an elongated rib having a substantially constant cross-section.

In an embodiment of the first aspect of the invention, the plurality of spacing members comprises a plurality of spacing members in the form of spots.

Combining elongated ribs with spot-form spacer members can be advantageous because spot-form spacer members introduce a smaller degree of resistance to convection while still carrying the load in the compressed stack than conventional elongated spacer members. Thus, the combination of elongated bars and spacing members in the form of spots, which are small in height, causes a very low degree of obstruction to the flow between the discs while still being able to guide the separated heavy phase or particles along the surfaces of the separation discs.

The spacing members in the form of spots may extend to a width of less than 5 mm along the surface of the separation disc. The width of the base of the spot-form spacer member may refer to or correspond to the diameter of the spot-form spacer member at the surface. If the base at the surface has an irregular shape, the width of the spacing members in the form of spots may correspond to the largest extension of the base at the surface.

As an example, the base of the spacing member in the form of a spot may extend to a width of less than 2 mm along the surface of the separation disc, such as to a width of less than 1.5 mm along the surface of the separation disc, such as to a width of about 1 mm or less than 1 mm along the surface of the disc.

Thus, due to the small dimensions compared to "conventional" large-sized spacing members in the form of, for example, elongated strips, the spacing members can be provided in larger numbers without blocking or significantly impeding the flow of the fluid mixture between the discs in the stack of separating discs.

The spacer member in the form of a spot may have a spherical or cylindrical shape as seen in the direction of its height.

As an example, the spacer member in the form of a spot has a cross section in the shape of a tip.

Thus, the plurality of spot-form spacing members may comprise spot-form spacing members which are tip-shaped and taper from a base at the surface of the separation disc towards a tip extending a certain height from the surface.

The spacer member in the form of a spot may be tip-shaped at least in a cross-section of the spacer member and thus the cross-section or the spacer member as a whole tapers from a base at the surface towards a tip extending a certain height from the surface. The height of the tip-shaped spacing member is the height perpendicular to the surface.

The spacing members in the form of spots may be tip-shaped in at least one cross-section, such as a cross-section perpendicular to a radius of the disc. Thus, the spacing means in the form of spots may form small ridges extending over the surface. The ridges may for example extend in the radial direction of the separation discs, i.e. substantially in the direction of flow of the fluid mixture along the separation discs.

The spacer members in the form of spots may be tip-shaped in more than one cross-section.

The spot-form spacer member may be tip-shaped as a whole, i.e. the respective cross-section of the spot-form spacer member is tip-shaped. Thus, the spot-form and tip-shaped spacing member may, for example, have the form of a cone (i.e. be conically shaped) or a pyramid, depending on the form of the base along the surface. The base at the surface may thus have a form like a cross, a circle, an ellipse, a square, or have a rectangular shape.

As an example, the tip shaped spacer member may have the form of a cone or pyramid, i.e. have a geometry that smoothly tapers from a flat base at the surface to the tip (i.e. to the apex at a certain height above the base). The apex may be located directly above the centroid of the base. However, the apex may also be located at a point which is not above the centroid, so that the tip-shaped spacing member has the form of an oblique cone or an oblique pyramid.

Equidistant spaces in a stack comprising thin metal separation discs are achieved if spot-form and tip-shaped spacing members are introduced on the surface of the thin metal separation discs. Thus, the separation capacity of the centrifugal separator can be further increased in this way by fitting a larger number of thinner metal separation discs into the stack. The invention will in this way facilitate the use of as thin separation discs as possible in order to maximize the number of separation discs and interspaces within a given stack height. Furthermore, the pointed shape of the spacer members and the spot form result in a smaller contact area between the spacer members of a disc and an adjacent disc, thus resulting in a larger surface area of the discs in the stack available for separation. Furthermore, the small contact area reduces the risk of dirt or impurities getting stuck in the disc stack during operation of the centrifugal separator, i.e. reduces the risk of contamination.

likewise, the equidistant spaces in the middle of the separation discs also contribute to reducing the risk of dirt or impurities getting stuck in the disc stack during operation of the centrifugal separator. Furthermore, the equidistant spaces provide improved separation performance in the centrifugal separator. Since the interspaces formed between the separation discs are equidistant, the separation performance is substantially the same everywhere in the separation zone formed in the disc stack and thus closer to the theoretically calculated separation performance of the centrifugal separator concerned. However, in prior art disc stacks, where the separation discs are deformed during operation of the centrifugal separator and thus create uneven interspaces between the discs, the separation performance within the disc stack is different and thus far from the theoretically calculated separation performance of the centrifugal separator concerned.

As an example, the spacing members in the form of spots may extend from the surface of the separation disc in a direction forming an angle of less than 90 degrees with the surface. Both the spacing members in spot form having a spherical or cylindrical shape and the spacing members in spot form being tip-shaped, as seen in the direction of the height of the spacing members in spot form, may extend from the surface of the separation disc in a direction forming an angle of less than 90 degrees with the surface.

Furthermore, the spacing members in the form of spots may extend from the surface of the separation disc substantially in the axial direction of the truncated conical shape of the separation disc. Both the spot-form spacing members having a spherical or cylindrical shape and the spot-form spacing members being tip-shaped, as seen in the direction of the height of the spot-form spacing members, may extend from the surface of the separation disc substantially in the axial direction of the truncated conical shape of the separation disc.

furthermore, the tips of the spot-formed spacing members may have a tip radius that is smaller than the height to which the spot-formed spacing members extend from the surface.

As an example, the tip of the spot-form spacing member may have a tip radius that is less than half the height to which the spot-form spacing member extends from the surface (such as less than a quarter of the height, such as less than a tenth of the height). With such "sharp" tips, the spacing members in the form of spots can be more easily attached to the surface of adjacent discs in the stack of discs, and the sharp tips also reduce clogging or obstruction of the flow of the fluid mixture between the discs in the stack of separate discs.

The plurality of separation discs comprising spacing members in the form of spots may comprise spacing members having different shapes. Thus, a single disc may comprise spacing members in the form of spots having different shapes, and a plurality of discs may comprise different discs having spacing members in the form of spots having different shapes, i.e. some discs may have only spacing members in the form of spherical spots, while some discs may have only spacing members in the form of pointed shaped spots.

However, the plurality of discs comprising the spacer members in the form of spots may also comprise separating discs having spacer members in the form of spots of the same type.

In an embodiment of the first aspect of the invention, a majority of the plurality of discs comprising spacer members in the form of spots are of the same kind in terms of number, shape, diameter and thickness of the spacer members in the form of spots.

Furthermore, most of the spacing members in the form of spots may be distributed over the surface of the separation disc at a mutual distance of less than 20 mm.

By way of example, the spacing members in the form of spots may be distributed over the surface of the separation disc at a mutual distance of less than 15 mm, such as about 10 mm or less than 10 mm.

The spacing members in the form of spots may be distributed evenly over the surface, in groups, or at different mutual distances over the surface, for example to form the following areas of the disc: the density of the spacer members in the form of spots is higher compared to the density of the spacer members in the form of spots on the rest of the same surface of the disc.

The inner or outer surface of the separation discs may have more than 10 spacer members/dm²(such as higher than 25 spacer members/dm²Such as higher than 50 spacer members/dm²Such as higher than 75 spacer members/dm²Such as about 100 spacer members/dm²Or more than 100 spacer members/dm²) The surface density of the spacer members in the form of spots.

Furthermore, the inner or outer surface of the separation discs may have more than 10 spacer members/dm²(such as higher than 25 spacer members/dm²Such as higher than 50 spacer members/dm²Such as higher than 75 spacer members/dm²Such as about 100 spacer members/dm²or more than 100 spacer members/dm²) And the separation discs have a thickness of less than 0.40 mm, such as less than 0.30 mm.

However, the entire inner surfaceor the outer surfaces need not all be covered by spacer members in the form of spots. As a result, in an embodiment of the first aspect of the invention, the inner or outer surface of the separation discs comprises discs having more than 10 spacer members/dm²(such as higher than 25 spacer members/dm²Such as higher than 50 spacer members/dm²Such as higher than 75 spacer members/dm²Such as about 100 spacer members/dm²Or more than 100 spacer members/dm²) Of the spacer member in the form of spots of (1.0 dm) or more²At least one region of (a).

In an embodiment of the first aspect of the invention, the separation disc further comprises at least one through hole in the truncated surface or is formed by at least one cut-out at the outer periphery of the separation disc. Such through-holes or cut-outs may form axial lifting channels in the stack of separation discs, which axial lifting channels may facilitate the supply and distribution of a fluid mixture, such as a liquid, into the interspaces in the stack of separation discs.

As a second aspect of the invention, a stack of separation discs adapted to be included in the interior of a centrifugal rotor for separating a liquid mixture is provided, comprising axially aligned separation discs having a truncated conical shape with an inner surface and an outer surface,

And wherein the axially aligned separation discs comprise a plurality of discs according to the first aspect above having spacing members and at least one elongated rib, the discs being arranged such that the elongated rib on a separation disc is not in contact with an adjacent separation disc.

The terms and definitions used in relation to the second aspect are the same as those discussed in relation to the first aspect hereinbefore.

The stack of separation discs may be aligned on an alignment member, such as a distributor. Thus, in an embodiment of the second aspect of the invention, the stack further comprises a distributor onto which the separation discs are aligned to form the stack.

The stack of separation discs may be adapted to be compressed by a force of more than 8 tonnes.

In an embodiment of the second aspect of the invention, the plurality of separation discs with the spacing members and the at least one elongated rib according to the first aspect above, or the number thereof, may be more than 50% of the total number of separation discs in the stack of separation discs, such as more than 75% of the total number of separation discs in the stack of separation discs, such as more than 90% of the total number of separation discs in the stack of separation discs. As an example, all discs of the disc stack may be discs according to the first aspect above having a spacing member and at least one elongate rib.

In an embodiment of the second aspect of the invention, the plurality of discs having spacing members and at least one elongate rib according to the first aspect hereinbefore are arranged such that a majority of the spacing members of a disc are displaced compared to the spacing members of an adjacent disc. Furthermore, the elongated ribs of a separation disc may also be displaced compared to the elongated ribs of an adjacent separation disc.

A "shift" of a spacing member or elongated rib as compared to a spacing member or elongated rib on an adjacent disc refers to the disc being arranged such that the spacing member or elongated rib is not located at the same position as the spacing member or elongated rib on the adjacent disc. Thus, the displaced spacer member does not abut the adjacent disc at the position where the adjacent disc has the spacer member.

Thus, a disc having a spacer member and at least one elongate rib according to the first aspect hereinbefore may be arranged such that the spacer member or elongate rib of a disc is not axially aligned with a spacer member or elongate rib of an adjacent disc. Thus, the spacer members may be radially displaceable with respect to the spacer members of the adjacent disc, as seen in an axial plane through the rotation axis, and/or circumferentially displaceable with respect to the spacer members of the adjacent disc, as seen in a radial plane through the rotation axis. Likewise, the elongated rib may be radially displaceable relative to the elongated rib of the adjacent disc, as seen in an axial plane through the rotational axis, and/or circumferentially displaceable relative to the elongated rib of the adjacent disc, as seen in a radial plane through the rotational axis.

the displacement of the spacer members or the elongated ribs may be achieved by rotating the disc in the circumferential direction compared to an adjacent disc, such as by a predetermined angle in the circumferential direction. Thus, when the separation discs are stacked on top of each other to form a stack, some or each separation disc may gradually turn through an angle in the circumferential direction.

As an example, the spacing members of a disc may be displaced by a circumferential distance and/or a radial distance of between 2-15 mm (such as between 3-10 mm, such as about 5 mm) relative to the corresponding spacing members of an adjacent disc. Likewise, the elongated rib may be displaced by a circumferential distance as described hereinabove.

As an example, the spacer members of a disc may be displaced with respect to the corresponding spacer members of an adjacent disc by a circumferential distance of about half the mutual distance between the spacer members of the discs. Likewise, the elongated rib may be displaced by a circumferential distance as described hereinabove.

Furthermore, the displacement of the spacer members and/or the elongated ribs may also be achieved by: separation discs having different patterns of spacing members and/or elongated ribs are used such that when the discs are stacked on top of each other (such as onto a distributor), the spacing members of a disc are not axially aligned with the spacing members of an adjacent disc and/or the elongated ribs of a disc are not axially aligned with the elongated ribs of an adjacent disc.

As an example, all spacing members and/or all elongated ribs of a disc may be displaced compared to the spacing members and/or elongated ribs of an adjacent disc.

A stack with spacer members displaced (i.e. the spacer members are not axially aligned on top of each other) is advantageous because a stack with spacer members displaced can provide better support for the thin discs, i.e. the thin discs in the stack have more support points, than if the discs were arranged such that the spacer members were aligned on top of each other in the stack of discs. Thus, the displaced stack of spacer members facilitates the use of thin discs in the stack.

Furthermore, a stack with displaced spacer members may be advantageous, since it allows an easy manufacturing or assembling of the disc stack, i.e. even if the spacer members are not axially aligned, the spacer members allow a uniform gap between the discs in the stack. In other words, in a disc stack, the spacer members have the ability to carry the large compressive forces in the compressed stack without having to be aligned above each other. This is thus in contrast to the conventional concept of forming a stack of discs, in which conventional elongated spacing members on the discs are axially aligned on top of each other in mutually adjacent separation discs throughout the stack of separation discs, or in other words in the prior art, in which the spacing elements are arranged in axially straight lines throughout the stack of separation discs in order to carry all the compressive forces in the compressed stack.

However, the discs in the stack may also be arranged such that the spacer members and the elongate ribs are axially aligned.

Thus, in an embodiment of the second aspect of the invention, the discs having spacer members are arranged such that most or all of the spacer members of a disc are axially aligned with the spacer members of an adjacent disc.

In an embodiment of the second aspect of the invention, the disc having the spacer members and the elongate ribs according to the first aspect hereinbefore is arranged such that the elongate ribs of a disc are axially aligned with the elongate ribs of an adjacent disc.

In an embodiment of the second aspect of the invention, the disc having spacer members and elongate ribs according to the first aspect above is arranged such that the elongate ribs of the disc are axially aligned with the elongate ribs of an adjacent disc, while most or all of the spacer members of the disc are displaced compared to the spacer members of an adjacent disc.

In an embodiment of the second aspect of the invention, the stack comprises more than 100 separation discs (such as more than 150 separation discs, such as more than 200 separation discs, such as more than 250 separation discs, such as more than 300 separation discs).

In an embodiment of the second aspect of the invention, the majority of all discs in the stack are discs according to the first aspect hereinbefore having spacing members and elongate ribs.

As an example, the stack may comprise more than 100 separation discs, and more than 90% of those separation discs may be separation discs having spacing members and elongated ribs according to the first aspect above.

As an example, the stack may comprise more than 150 separation discs, and more than 90% of those separation discs (such as all separation discs) may be separation discs having spacing members and elongated ribs according to the first aspect hereinbefore.

As an example, the stack may comprise more than 200 separation discs, and more than 90% of those separation discs (such as all separation discs) may be separation discs having spacing members and elongated ribs according to the first aspect hereinbefore.

As an example, the stack may comprise more than 250 separation discs, and more than 90% of those separation discs (such as all separation discs) may be separation discs having spacing members and elongated ribs according to the first aspect hereinbefore.

As an example, the stack may comprise more than 300 separation discs, and more than 90% of those separation discs (such as all separation discs) may be separation discs having spacing members and elongated ribs according to the first aspect hereinbefore.

The separation discs according to the first aspect above in a disc stack as exemplified above having spacing members and elongated ribs may have a diameter of more than 300 mm and comprise more than 300 spot-form spacing members (such as more than 1000 spot-form spacing members, such as more than 1300 spot-form spacing members), or these separation discs may have a diameter of more than 350 mm and comprise more than 500 spot-form spacing members (such as more than 1400 spot-form spacing members, such as more than 1800 spot-form spacing members), or these separation discs may have a diameter of more than 400 mm and comprise more than 600 spot-form spacing members (such as more than 1700 spot-form spacing members, such as more than 2200 spot-form spacing members), or these separation discs may have a diameter of more than 450 mm, and comprises more than 700 spacer members in the form of spots (such as more than 1900 spacer members in the form of spots, such as more than 2800 spacer members in the form of spots), or the separation discs may have a diameter of more than 500 mm and comprise more than 900 spacer members in the form of spots (such as more than 2700 spacer members in the form of spots, such as more than 3600 spacer members in the form of spots), or the separation discs may have a diameter of more than 530 mm and comprise more than 1000 spacer members in the form of spots (such as more than 3000 spacer members in the form of spots, such as more than 4000 spacer members in the form of spots).

As a result, the stack may comprise more than 300 separation discs having a diameter of more than 500 mm, and more than 90% of those separation discs (such as all separation discs) may be separation discs according to the first aspect above having spacing members and elongated ribs and comprise more than 3000 spacing members in the form of spots (such as more than 4000 spacing members in the form of spots).

In an embodiment of the second aspect of the invention, the stack of separation discs is arranged such that the spacing members in the form of spots are the main load carrying elements in the stack of separation discs.

This means that most of the compressive force is supported by the spacer members in the form of spots in the disc stack.

In an embodiment of the second aspect of the invention, the plurality of discs having spacer members and elongated ribs according to the first aspect above are free of discs of spacer members other than the spot-form spacer members for forming gaps between discs in the stack.

Thus, a plurality of discs with spacer members and elongate ribs and also the entire stack of discs according to the first aspect hereinbefore may comprise only spacer members in the form of spots as load bearing elements.

In an embodiment of the second aspect of the invention, the stack of separation discs further comprises at least one axial lifting channel formed by at least one through hole in the truncated surface or by at least one cut-out at the outer periphery of a plurality or all of the separation discs in the stack.

As discussed in relation to the first aspect above, such axial riser channels may facilitate the supply and distribution of a fluid mixture (such as a liquid) into the interspaces in the stack of separation discs.

As a third aspect of the present invention, a centrifugal separator for separating at least two components of a fluid mixture having different densities is provided, the centrifugal separator comprising:

A fixed frame, a movable frame and a movable frame,

A main shaft rotatably supported by the frame,

A centrifuge rotor mounted to the first end of the main shaft for rotation therewith about a rotation axis (X), wherein the centrifuge rotor comprises a rotor housing enclosing a separation space in which a stack of separation discs is arranged to rotate coaxially with the centrifuge rotor,

A separator inlet extending into the separation space for supplying a fluid mixture to be separated,

A first separator outlet for discharging the first separated phase from the separation space,

A second separator outlet for discharging a second separated phase from the separation space;

Wherein the stack of separation discs is as according to the second aspect of the invention discussed hereinbefore.

the terms and definitions used in relation to the third aspect are the same as those discussed in relation to the other aspects above.

Centrifugal separators are used for the separation of fluid mixtures, such as gas mixtures or liquid mixtures. The stationary frame of the centrifugal separator is a non-rotating part and the spindle is supported by the frame by at least one bearing arrangement, such as by at least one ball bearing.

The centrifugal separator may further comprise a drive member arranged for rotating the main shaft and a centrifuge rotor mounted on the main shaft. Such drive means for rotating the main shaft and the centrifuge rotor may comprise an electric motor having a rotor and a stator. The rotor may be provided on or fixed to the main shaft such that, during operation, the rotor transmits drive torque to the main shaft, and thus to the centrifuge rotor.

Alternatively, the drive component may be provided adjacent the main shaft and rotate the main shaft and the centrifuge rotor by suitable gearing (such as belt or gear gearing).

The centrifuge rotor is contiguous with the first end of the main shaft and is thus mounted for rotation with the main shaft. During operation, the spindle thus forms a rotation axis. The first end of the main shaft may be an upper end of the main shaft. The spindle is thus able to rotate about an axis of rotation (X).

The spindle and the centrifuge rotor may be arranged to rotate at a speed above 3000 rpm, such as above 3600 rpm.

The centrifuge rotor further encloses a separation space in which the separation of the fluid mixture takes place. Thus, the centrifuge rotor forms a rotor housing for the separation space. The separation space comprises a stack of separation discs as discussed above in relation to the second aspect of the invention, and the stack is arranged centrally around the axis of rotation. Such a separation disc thus forms a surface-enlarging insert in the separation space.

The separator inlet for the fluid mixture to be separated (i.e. the feed) may be a stationary pipe arranged for supplying the feed to the separation space. The inlet may also be provided in a rotating shaft, such as a spindle.

The first separator outlet for discharging the first separated phase from the separation space may be a first liquid outlet.

The second separator outlet for discharging the second separated phase from the separation space may be a second liquid outlet. Thus, the separator may comprise two liquid outlets, wherein the second liquid outlet is arranged at a larger radius from the axis of rotation than the first liquid outlet. Thus, liquids having different densities may be separated and discharged via such first and second liquid outlets, respectively. Accordingly, the separated liquid having the lowest density may be discharged via the first separator outlet, while the separated liquid phase having the higher density may be discharged via the second separator outlet.

During operation, the sludge phase, i.e. the mixed solid and liquid particles forming the heavy phase, may be collected in the outer peripheral portion of the separation space. Thus, the second separator outlet for discharging the second separated phase from the separation space may comprise an outlet for discharging such sludge phase from the periphery of the separation space. The outlet may be in the form of a plurality of peripheral ports extending through the centrifuge rotor from the separation space to the rotor space between the centrifuge rotor and the stationary frame. The peripheral ports may be arranged to open intermittently during short periods of time, in the order of milliseconds, to enable discharge of the sludge phase from the separation space to the rotor space. The peripheral port may alternatively be in the form of a nozzle that is continuously open during operation to allow for continuous discharge of sludge.

However, the second separator outlet for discharging the second separated phase from the separation space may be a second liquid outlet, and the centrifugal separator may further comprise a third separator outlet for discharging the third separated phase from the separation space.

such a third separator outlet comprises an outlet for discharging sludge phase from the periphery of the separation space as discussed above, and may be in the form of a plurality of peripheral ports arranged to open intermittently, or in the form of nozzles that are continuously open during operation to allow for continuous discharge of sludge.

The centrifugal separator according to the third aspect of the invention is advantageous in that it allows operation at high flow rates of the feed material, i.e. the mixture to be separated.

in certain separator applications, the separated fluid during the separation process is preserved under special hygienic conditions and/or without any entrapped air and high shear forces, such as when the separated product is sensitive to such effects. Examples belonging to this category are the isolation of dairy products, beer and in biotechnological applications. For such applications, so-called gas-tight separators have been developed, in which the separator bowl or centrifuge rotor is completely filled with liquid during operation. This means that air or free liquid surface will not be present in the rotor.

In an embodiment of the first aspect of the invention, at least one of the separator inlet, the first separator outlet or the second separator outlet is mechanically hermetically sealed.

The hermetic seal reduces the risk of oxygen or air entering the separation space and contacting the liquid to be separated.

Thus, in an embodiment of the third aspect of the invention, the centrifugal separator is used for separating dairy products, such as separating milk into cream and skim milk.

In an embodiment of the third aspect of the invention, the stack of separation discs comprises at least 200, such as at least 300, separation discs having a diameter of at least 400 mm, and wherein the plurality of discs having spot-form spacing members comprises at least 2000 spot-form spacing members on each disc.

as an example, the stack of separation discs may comprise more than 300 separation discs, and more than 90% of those separation discs (such as all separation discs) may have a diameter of at least 500 mm, and may be separation discs having spacing members in the form of spots comprising at least 4000 spacing members in the form of spots on each disc.

Drawings

Fig. 1a-c show an embodiment of a separation disc. Fig. 1a is a perspective view, fig. 1b is a bottom view, i.e. showing the inner surface of the separation disc, and fig. 1c is a close-up view of the outer periphery of the inner surface.

fig. 2a-d show further embodiments of the separation disc with elongated ribs.

Figures 3a-c show embodiments of differently shaped elongated ribs.

Figures 4a-f show embodiments of the spacer member in the form of spots and different tip shapes.

Figure 5 shows the relationship between the spacer members and the elongate ribs.

Fig. 6a-d show different spot-form and tip-shaped spacer members.

Fig. 7 shows an embodiment of a disc stack.

Fig. 8a-c show an embodiment of a disc stack in which the spacing members in the form of spots of separating discs are displaced with respect to the spacing members in the form of spots of adjacent discs. Fig. 8a is a perspective view, fig. 8b is a radial cross-section, and fig. 8c is a close-up view of the inner surface.

Fig. 9a and 9b show an embodiment of a disc stack in which the spacing members in the form of spots of separating discs are axially aligned with the spacing members in the form of spots of adjacent discs. Fig. 9a is a radial cross-section and fig. 9b is a close-up view of the inner surface.

Fig. 10 shows a section of a centrifugal separator.

Detailed Description

Examples of separation discs, a stack of separation discs and a centrifugal separator according to the present disclosure will be further illustrated by the following description with reference to the drawings.

Fig. 1a-c show a schematic view of an embodiment of a separation disc. Fig. 1a is a perspective view of a separation disc 1 according to an embodiment of the present disclosure. The separation disc 1 has a truncated conical shape (i.e. a truncated conical shape) along the conical axis X1. The axis X1 is thus the direction of the axis passing through the apex of the corresponding conical shape. The conical surface forms a cone angle a with the cone axis X1. The separation disc has an inner surface 2 and an outer surface 3, the inner surface 2 and the outer surface 3 extending radially from an inner circumferential edge 6 to an outer circumferential edge 5. In this embodiment the separation disc is further provided with a number of through holes 7, the through holes 7 being located at a radial distance from both the inner and outer circumferential edges. When forming a stack with other separation discs belonging to the same kind, the through-holes 7 may thus form axial distribution channels for, for example, a liquid mixture to be separated, which promote an even distribution of the liquid mixture throughout the stack of separation discs. The separation disc further comprises a number of spot-shaped spacing members 4 extending over the inner surface of the separation disc 1. These distance members 4 provide interspaces between mutually adjacent separation discs in the stack of separation discs. Examples of spacer members in the form of spots are shown in more detail in fig. 4a-4 f. As can be seen in fig. 1a, only the inner surface 2 is provided with spacing members 4 in the form of spots, while the outer surface 3 is free of spacing members 4 in the form of spots, and also free of other spacing members. The inner surface 2 is also free of spacing members other than the spot-form spacing members 4. Thus, in a stack of separation discs 1 belonging to the same kind, the spacing members 4 in the form of spots are the only spacing members, i.e. the only members forming the interspaces and the axial distances between the discs in the stack. The spacer members in the form of spots are thus the only load bearing elements on the discs 1 when the discs are stacked axially on top of each other. This is thus a difference from conventional separation discs, in which several elongated radially extending distance members on each disc form gaps and carry the compressive forces in the stack of discs.

However, as an alternative, it will be appreciated that the outer surface 3 may be provided with spacer members 4 in the form of spots, while the inner surface 2 may be free of spacer members 4 in the form of spots, and also free of other spacer members.

Fig. 1b shows the inner surface 2 of the separation disc 1. The spacing members 4 in the form of spots extend from a base at the inner surface 2, the base having a width along the inner surface 2 of the separation disc 1 of less than 1.5 mm. Furthermore, the mutual distance d1 between the spacer members 4 in the form of spots is about 10 mm, and the entire inner surface 2 comprises about 100 spacer members/dm². The inner surface 2 further comprises six elongated ribs extending radially outwards from the inner periphery to the outer periphery of the separation disc. Thus, the inner circumference represents a first position and the outer circumference represents a second position at a radial distance greater than the radial distance of the first position. The elongated ribs 36 are smaller in height than the spacing members in the form of spots and thus do not contribute in forming the interspaces in the stack of separation discs.

At the inner circumference 6 of the separation disc 1 there are also a number of cut-outs 13 in order to facilitate stacking on e.g. a distributor.

Fig. 1c shows a close-up of the outer circumference 5 of the inner surface 2 of the separation disc 1. In this embodiment the density of the spacer members 4 in the form of spots is higher at the outer periphery than on the rest of the disc. This is achieved by: more spacer members in the form of spots are arranged in the outer peripheral zone P such that the distance d2 between the radially outermost spacer members 4 in the outer peripheral zone P is smaller than the distance d1 between the spacer members 4 outside this zone. The peripheral region P may extend, for example, 10 mm radially from the outer periphery 5. The higher density of the spacer members at the outermost periphery is advantageous, because the higher density reduces the risk that mutually adjacent discs in the disc stack touch each other at the outermost periphery where the compression and centrifugal forces are high. Mutually adjacent discs touching each other will block the gap and thus lead to a reduced efficiency of the disc stack.

Figures 2a-d show different variants of the disc as seen in figures 1 a-c. In fig. 2a the elongated ribs have a smaller length and extend on the inner surface all the way to the outer circumferential edge, but starting at a radial position such that the radially inner portion 41 of the separation disc 1 is free of elongated ribs. In fig. 2b, the elongate ribs 36 are curved. Fig. 2c shows an example of a disc with 12 elongated ribs arranged on the inner surface, each extending straight in the radial direction. However, as discussed above, the ribs may be straight, but extend in a direction that forms an angle with respect to the radial direction. Fig. 2d shows an embodiment of the separation disc 1 having shorter ribs, i.e. ribs extending a shorter distance in the radial direction, than in the previous examples. The ribs 36 extend from a first location 39, different from the inner periphery, and to a second location 40 radially inward compared to the outer periphery.

Figures 3a-c show different examples regarding the shape of the ribs 36. The ribs 36 in fig. 3a-c are not drawn to scale but merely represent a schematic representation of the shape. The ribs 36 of fig. 3a extend a distance L along the surface of the separation disc. L may be about 50-250 mm. The ribs 36 extend a height h from the surface and have an additional width w at the surface. The width w is thus the width at the base portion 37 of the rib 36. The width w may be, for example, less than 20 mm (such as about 10 mm or less than 10 mm). The height h may for example be between 0.20 and 0.40 mm. The width w at the surface is wider than the width at the outermost portion 38 of the rib 36 (i.e., at a position that is at a height h from the surface). Thus, the elongate ribs taper outwardly from the surface to the outermost portion 38. In fig. 3a, the cross-section perpendicular to the direction in which the ribs 36 extend is tip-shaped with a sharp tip. In fig. 3b, the ribs also taper from the base portion 37 to the outermost portion 38, but the outermost portion is flat with a surface that is substantially parallel to the base portion 37 (i.e., parallel to the surface of the disk). In fig. 3c, the ribs 36 also taper from the surface, but the cross-section perpendicular to the direction in which the ribs 36 extend is tip-shaped with a more smoothly rounded tip than the cross-section of the ribs 36 of fig. 3 a.

Fig. 4a-f show embodiments of different types of spacer members in the form of spots that can be used as spacer members on the separation discs of the present disclosure. Fig. 4a shows a section of a part of a separation disc 1, in which separation disc 1 spacing members 4 in the form of spots are arranged on the inner surface 2 of the disc 1 along a line extending in the radial direction. The outer surface 3 is free of any kind of spacer members. The spacing members 4 are integrally formed in the separation disc 1, i.e. in one piece with the material of the separation disc itself. The spacer member 4 is tip-shaped and tapers from a surface to a tip that extends a certain distance or height from the inner surface 2. Fig. 4b shows a cross-section similar to the disc of fig. 4a, but in this example the tip shape and the spacer members in spot form are provided only on the outer surface 3, whereas the inner surface 2 is free of spacer members in spot form.

Fig. 4c also shows a cross-section of a part of another example of a separation disc 1, in which separation disc 1 the spacing members 4 in the form of spots are arranged on the inner surface 2 of the disc 1 along a line extending in the radial direction, while the outer surface 3 is free of any kind of spacing members. In this example, the spacer member 4 is shaped as a hemisphere protruding from the inner surface 2. Fig. 4d shows a cross-section similar to the disc of fig. 4c, but in this example the spacing members are provided in the form of hemispheres and spots only on the outer surface 3, whereas the inner surface 2 is free of the spacing members in the form of spots.

Fig. 4e also shows a cross section of a part of another example of a separation disc 1, in which separation disc 1 the spacing members 4 in the form of spots are arranged on the inner surface 2 of the disc 1 along a line extending in the radial direction, while the outer surface 3 is free of any kind of spacing members. In this example, the spacer member 4 is shaped as a cylinder protruding from the inner surface 2. Fig. 4f shows a cross-section similar to the disc of fig. 4e, but in this example the cylindrical and spot-formed spacer members are provided only on the outer surface 3, while the inner surface 2 is free of spot-formed spacer members.

Fig. 5 shows the relationship in height between the elongate ribs 36 and the spacer members 4. The disc as seen in fig. 5 is similar to the disc in fig. 4a, with a spacing member 4 in the form of a spot extending a height H from the inner surface 2 and in the shape of a tip. The dimensions of the elongated ribs 36 extending a height h from the surface are also plotted in fig. 5. The relation between H and H is that H is larger than H and H/H >0.7, i.e. the elongated ribs 36 do not carry any weight in the compressed stack of separation discs 1.

fig. 6a-d show embodiments of different tip shapes and spot-form spacing members that may be used on the separation discs of the present disclosure. Fig. 6a shows a close-up view of an embodiment of the tip-shaped spacing member 4. A tip-shaped spacing member 4 extends from a base 8 on the inner surface 2. The base 8 extends to a width of less than 1.5 mm along the inner surface 2 of the separation disc 1. The tip-shaped spacing member tapers from the base 8 to a tip 9 located at a distance H from the base. Thus, the height of the tip-shaped spacing member is a distance H, in this case between 0.15 mm and 0.30 mm, whereas the thickness of the separating discs, as shown by distance z in fig. 6b, is between 0.30 mm and 0.40 mm. In the example of fig. 6a, the tip-shaped spacing member 4 extends from the base 8 in a direction y1 substantially perpendicular to the inner surface 2. The direction y1 is thus parallel to the normal N of the inner surface 2.

Fig. 6b shows an example of a tip-shaped distance member 4 extending from the surface of the separation disc in a direction forming an angle of less than 90 degrees with the surface. The spacer member 4 of fig. 6b is identical to the spacer member shown in fig. 6a, but with the following differences: the spacer member 4 of fig. 6b extends in a direction y2 forming an angle with the normal N of the inner surface. In this case, the tip-shaped spacing member 4 extends in a direction y2 forming an angle β 1 with the inner surface 2, and the angle β 1 is smaller than 90 degrees. Thus, the tip 9 extends from the base 8 in a direction y2 that forms an angle with the surface of approximately 60-70.

Fig. 6c shows a further example of a tip-shaped distance member 4 extending from the surface of the separation disc in a direction forming an angle of less than 90 degrees with the surface. The spacer member 4 of fig. 6c is identical to the spacer member shown in fig. 6b, but with the following differences: the spacer member 4 of fig. 6c extends in a direction y3 forming an angle β 2 with the inner surface that is smaller than the angle β 1 in fig. 6 b. In this example, the angle β 2 is substantially the same as the alpha angle α of the separation disc 1 (i.e. half of the opening angle of the corresponding conical shape of the separation disc). Thus, the angle α is the angle of the conical portion of the separation disc 1 with the conical axis X1. The angle alpha may be about 35 deg.. In other words, the tip-shaped spacing members 4 extend from the inner surface 2 of the separation disc 1 substantially in the axial direction of the truncated conical shape of the separation disc 1. Thus, in the formed stack of separation discs, the spacing members in the form of substantially axially extending spots may adhere better to adjacent discs in the stack, thereby further reducing the risk of non-uniformity in the size of the interspaces between the discs when the stack is compressed.

It will be appreciated that most or all of the spot-shaped spacing members 4 on the separation disc may extend in the same direction, i.e. that most or all of the spot-shaped spacing members 4 on the separation disc may extend in a direction substantially perpendicular to the surface, or that most or all of the spot-shaped spacing members 4 on the separation disc and the tip-shaped spacing members 4 may extend in a direction forming an angle with the surface, i.e. as in the examples shown in fig. 6b and 6 c.

Furthermore, the tip 9 of the spacing member in the form of a spot having a tip shape has a tip radius R_{Tip end}And is further shown in more detail in fig. 6 d. The tip radius R_{Tip end}Is small in order to obtain a tip that is as sharp as possible. As an example, the tip radius R_{Tip end}Which may be smaller than the height H, the spacer members 4 in the form of spots extend from the inner surface 2 to the height H. Furthermore, the tip radius R_{Tip end}May be less than half of height H, such as less than one tenth of height H.

Fig. 7 shows an embodiment of a disc stack 10 comprising separation discs 1 according to the present disclosure. The disc stack 10 comprises separation discs 1 arranged on a distributor 11. For the sake of clarity, fig. 7 shows only a few separation discs 1, but it will be understood that the disc stack 10 may comprise more than 200 separation discs 1, such as more than 300 separation discs. The interspaces 28 are formed between the stacked separation discs 1 due to the spacing members, i.e. the interspaces 28 are formed between the separation disc 1a and adjacent separation discs 1b and 1c below and above the separation disc 1a, respectively. The through-holes in the separation discs form axial rising channels 7a extending through the stack. Furthermore, the disc stack 10 may comprise a top disc (not shown), i.e. a disc arranged at the topmost part of the stack, which is not provided with any through holes. Such top trays are known in the art. The top disc may have a larger diameter than the other separation discs 1 in the disc stack in order to assist in guiding the separated phase away from the centrifugal separator. The top disc may further have a greater thickness than the rest of the separation discs 1 of the disc stack 10. The separation discs 1 may be provided on the distributor 11 using cut-outs 13 at the inner periphery 5 of the separation discs 10, which fit into corresponding wings 12 of the distributor.

Fig. 8a-c show an embodiment where the separation disc 1 comprises spacing members in the form of spots. The separation discs 1 are arranged in the stack 10 in the axial direction such that most of the spacing members 4a in the form of spots of the discs 1a are displaced in comparison to the spacing members 4b in the form of spots of the adjacent discs 1 b. In this embodiment, this is performed by rotating the disc 1a to a small extent in the circumferential direction compared to the adjacent disc 1b, as shown by arrow "a" in fig. 8 a-c. Thus, as seen in fig. 8a, adjacent separation discs 1a and 1b are axially aligned along the axis of rotation X2 (which is in the same direction as the conical axis X1 as seen in fig. 1 and 2), but due to the arrangement of the spot-form spacing members, the spot-form spacing members 4a of the separation disc 1a are not axially aligned above the corresponding spot-form spacing members 4b of the separation disc 1 b. As an example, the discs 1a and 1b are arranged such that the spot-form spacer members 4a of the disc 1a are displaced by a circumferential distance z3 with respect to the corresponding spot-form spacer members 4b of the disc 1 b. The distance z3 may be about half the distance of the mutual distance between the spacer members in the form of spots on the disc, such as between 2-10 mm.

In other words, the separation discs of the disc stack 1 are arranged such that the spot-formed spacing members 4a of the separation disc 1a do not abut the adjacent disc 1b at the location where the adjacent disc 1b has the spot-formed spacing members 4 b. This is also shown in fig. 8b, which fig. 8b shows a cross section of the adjacent discs 1a and 1 b. The spot-shaped spacing members 4a of the disc 1a and the spot-shaped spacing members 4b of the disc 1b may be provided at the same radial distance, but offset in the circumferential direction. Furthermore, fig. 8c shows a close-up view of the outer circumferential edge 5 of the disc 1 b. The spot-form members 4a of the adjacent discs 1a abut the separation discs 1b at positions indicated by crosses in fig. 8c, which are positions shifted in the circumferential direction as shown by the arrow "a" compared to the positions of the spot-form spacing members 4 b.

However, the separation discs 1 of the disc stack 10 may be arranged on the distributor 11 such that the majority of the spacing members of a disc are axially aligned with the 8 spacing members of an adjacent disc. This is illustrated in fig. 9a and 9b, where in fig. 9a and 9b adjacent separation discs 1a and 1b are arranged such that the spacing members 4a in the form of spots of the discs 1a are aligned with the spacing members 4b in the form of spots of the discs 1 b. Fig. 9a shows a cross section of adjacent discs 1a and 1b with the spacer members 4a and 4b aligned, while fig. 9b shows a close-up view of the outer circumferential edge 5 of the disc 1 b. In contrast to the embodiment shown in fig. 8c, the spacing members 4a in the form of spots of adjacent discs 1a actually abut the separation disc 1b at the location of the spacing members 4b in the form of spots of the discs 1b, as indicated by the crosses in fig. 9 b.

Fig. 10 shows a schematic example of a centrifugal separator 14 according to an embodiment of the present disclosure, the centrifugal separator 14 being arranged to separate a liquid mixture into at least two phases. Further, it will be understood that fig. 10 is a schematic and, thus, not drawn to scale.

The centrifugal separator 14 comprises a rotating part arranged for rotation about an axis of rotation (X2) and comprises a rotor 17 and a spindle 16. The main shaft 16 is supported in a stationary frame 15 of the centrifugal separator 14 in a bottom bearing 24 and a top bearing 23. The stationary frame 15 surrounds the rotor 17.

The rotor 17 forms within itself a separation chamber 18, in which separation chamber 18, during operation, centrifugal separation of, for example, a liquid mixture will take place. The separation chamber 18 may also be referred to as separation space 18.

the separation chamber 18 is provided with a stack 10 of frustoconical separation discs 1 in order to achieve an effective separation of the fluid to be separated in the interspaces 28 between the discs 1. The stack 10 of truncated conical separation discs 1 is an example of a surface enlarging insert. These discs 1 are fitted centrally and coaxially with the rotor 17 and further comprise through holes which form axial channels 25 for the axial flow of the liquid when the separation discs 1 are fitted in the centrifugal separator 14. The separation discs 1 are as discussed in the examples hereinbefore and comprise both spacing members and elongate ribs in the form of spots integrally formed on the inner surface of each disc.

In fig. 10, only a few discs 1 are shown in the stack 10, and in this case the stack comprises more than 200 separating discs with spacing members in the form of spots.

The rotor 17 has a liquid light phase outlet 33 and a liquid heavy phase outlet 34 extending therefrom, the liquid light phase outlet 33 for the lower density component separated from the liquid mixture and the liquid heavy phase outlet 34 for the higher density component or heavy phase separated from the liquid mixture. Outlets 33 and 34 extend through frame 15. The outlets 33, 34 may also be referred to as separator outlets 33, 34. In some applications, the separator 14 contains only a single liquid outlet, such as only the liquid outlet 33. Depending on the liquid material to be treated. The rotor 15 is further provided with a third outlet for discharging sludge that has accumulated at the periphery of the separation chamber 18. The sludge outlet is in the form of a number of peripheral ports 19, which peripheral ports 19 extend from the separation chamber 18 through the rotor housing to the surrounding space 20 outside the centrifuge rotor 17. The peripheral port 19 may be capable of being opened intermittently during a short period of time, for example in the order of milliseconds, and allows sludge to be discharged completely or partially from the separation space using a conventional intermittent discharge system as is known in the art.

The centrifugal separator 1 is further provided with a drive motor 21. The motor 21 may, for example, comprise a stationary element 22 and a rotatable element 26, which surrounds the main shaft 16 and is connected to the main shaft 16 such that it transmits a driving torque to the main shaft 16 and thus to the rotor 17 during operation. The drive motor 21 may be an electric motor. Further, the drive motor 21 may be connected to the main shaft 16 through a transmission mechanism. The transmission may be in the form of a worm gear including a pinion gear and an element connected to the main shaft 16 for receiving the drive torque. The transmission mechanism may alternatively take the form of a propeller shaft, a drive belt or the like, and the drive motor may alternatively be directly connected to the main shaft.

A central conduit 27 extends through the main shaft 16, the central conduit 27 taking the form of a hollow tubular member. In this embodiment, the central conduit 27 forms an inlet conduit for supplying the liquid mixture for centrifugal separation to the separation space 18 via an inlet 29 of the rotor 17. The inlet duct may also be referred to as the separator inlet. The introduction of the liquid material from the bottom provides a gentle acceleration of the liquid material. The main shaft 16 is further connected to a stationary inlet conduit 30 at the bottom end of the main shaft 16, so that the liquid material to be separated can be transported by the transport mechanism to the central conduit 27.

A first mechanical hermetic seal 32 is arranged at the bottom end of the main shaft 16 to seal the hollow main shaft 16 to the stationary inlet duct 30. The hermetic seal 32 is an annular seal that surrounds the bottom end of the main shaft 16 and surrounds the stationary pipe 30. Furthermore, the liquid light phase outlet 33 and the liquid heavy phase outlet 34 may also be hermetically mechanically sealed. Alternatively, a centripetal pump (such as a paring disc) may be arranged at the outlets 33 and 34 to assist in conveying the separated phases out of the separator.

During operation of the decoupler in fig. 10, the rotor 17 is rotated by torque transmitted from the drive motor 21 to the main shaft 16. Via the central duct 27 of the main shaft 16, liquid material to be separated, such as milk, is brought into the disc stack 10 via the inlet 29 and the axial lifting channel 25. In an airtight type inlet 29, the acceleration of the liquid material starts at a small radius and gradually increases as the liquid exits the inlet and enters the separation chamber 18 and the disc stack 10. Furthermore, as discussed above, the separator 14 may also have a gas-tight outlet, and the separation chamber 18 may be expected to be completely filled with liquid during operation. In principle, this means that preferably air or a free liquid surface will not be present in the rotor 17. However, it is also possible to introduce the liquid when the rotor is already running at its operating speed. The liquid material can thus be introduced continuously into the rotor 17.

The path of the liquid material to be separated through the main shaft 16 to the separation space 18 is shown by the arrow "B" in fig. 10.

Depending on the density, different phases in the liquid are separated in the interspaces 28 between the separation discs of the stack 10 fitted in the separation space 18. The heavier components of the liquid move radially outwards between the separation discs and the phase with the lowest density moves radially inwards between the separation discs and is forced through an outlet 33 arranged at the radially innermost layer in the separator. The liquid having the higher density is instead forced out through an outlet 34 located at a radial distance from the radial layer greater than the outlet 33. Thus, during separation, an intermediate phase between the liquid having the lower density and the liquid having the higher density is formed in the separation space 18. Solids or sludge accumulate at the periphery of the separation space 18 and can be emptied intermittently from the separation space by opening the sludge outlet, i.e. the peripheral port 19, whereupon sludge and a certain amount of liquid are discharged from the separation space by means of centrifugal force. The opening and closing of the peripheral port 19 is controlled by means of a sliding drum bottom 35, the sliding drum bottom 35 being movable between an open position and a closed position along a direction parallel to the rotation axis (X2).

In the embodiment of fig. 10, the material to be separated is introduced via the central conduit 27 of the main shaft 16. However, the central conduit 27 may also be used for draining, for example, liquid light phase and/or liquid heavy phase. Thus, in an embodiment, the central duct 27 comprises at least one additional duct, i.e. at least two ducts. In this way, the liquid mixture to be separated can be introduced to the rotor 17 via the central conduit 27 and, simultaneously, the liquid light phase and/or the liquid heavy phase can be discharged through such additional conduits, for example, within the central conduit 27 or extending around the central conduit 27.

The invention is not limited to the embodiments disclosed but may be varied and modified within the scope of the claims presented below. The invention is not limited to the type of separator shown in the drawings. The term "centrifugal separator" also includes centrifugal separators with a substantially horizontally oriented axis of rotation and separators having a single liquid outlet.