EP1732697B9 - Solid-wall centrifuge comprising a weir provided with a stationary deflector plate - Google Patents

Description

The invention relates to a solid bowl centrifuge according to the preamble of claim 1.

Full-bowl centrifuges are each made of EP 0 702 599 B1 and the US 5,593,377 known. These two documents disclose a solid bowl screw centrifuge with a drum having a weir provided with a passage for discharging a liquid phase separated in the centrifugal drum, the passage being associated with a throttle disc formed as a non-rotating part whose distance is variable to the passage, so that an adjustment of the liquid level in the centrifugal drum by an axial adjustment of the throttle plate is possible.

Due to the stationary throttle disk does not adversely affect the operation of the centrifugal drum, in particular, no adverse braking effect is given by the annular gap between the rotating weir and the stationary liquid disc passing liquid.

The annular gap creates a flow resistance which is greater, the smaller the axial distance between the weir and the throttle plate. As the flow resistance increases, however, a larger liquid pressure at the passage is required, which leads to an increase in the liquid level in the centrifugal drum. If the axial distance between the weir and the throttle plate is increased, falls the liquid level in the centrifugal drum to a value which is caused by the passage of the weir without such a throttle disk.

This solution has proven excellent in practice, since it is simple and inexpensive to implement by the design as not in operation with the drum rotating, stationary construction without the need for the transfer of restoring forces on co-rotating parts of the centrifuge and the advantage of excellent Possibility to control and / or regulation of the separation or clarification process in the drum offers.

The DE PS 966,080 shows a Vollmantelschneckenzentrifuge, the liquid discharge from the drum is directed radially outward, where the liquid is collected in a kind of annulus with a nearly circular cross-section. Radial outward from the drum directed liquid discharges also shows the DE PS 706 968 ,

The DE 25 15 452 A1 also shows behind the axially directed liquid discharges a co-rotating with the drum plate, which deflects the exiting liquid almost 180 ° in the opposite axial direction.

The US 20 83 899 shows a centrifuge with vertical axis of rotation without throttle disc.

The FR 20 57 600 and the FR 20 54 722 show in each case solid bowl centrifuges with axially directed to the axis of rotation liquid discharge, where exiting liquid can splash back from a wall behind the outlets back to the drum.

From the generic WO 01/85349 A1 it is known ( Fig. 3 ), the axial adjustability of a non-co-rotating throttle plate, the principle of which the EP 0 702 599 B1 corresponds to realize behind the passage openings of the drum, characterized in that the throttle disc is pivotable by means of an actuating drive about a pivot bearing on its outer periphery like a flap. through an annular groove - there called "Ringtasse", the flow conditions at the passage are to be optimized. In Fig. 1 This document is also a variant described in which a kind of cylindrical ring with a wall which is aligned parallel to the axis of rotation of the drum is disposed in the annular gap between a stationary housing wall and the centrifuge lid, wherein in this ring adjustable perforated apertures are arranged, through which the discharged liquid is injected directly radially outward.

Compared to the generic prior art, it is the object of the invention to realize a gentler discharge of the liquid phase from the weir in a simple manner.

The invention solves this problem by the subject matter of claim 1.

Thereafter, in front of the drum lid outside the centrifugal drum - within the catching chamber - a resting during operation, i. not with the drum rotating - at least partially widening away from the drum cover - widening disc arranged which has at least one inner shell, wherein the distance of the inner shell to the axis of rotation is not constant but expands or increases.

By widening is to be understood that the baffle is not a flat disc but a kind of "sleeve-like" component with an at least over part of the axial extension or the entire axial extension changing - here enlarging - inner diameter. The deflection disc thus has a defined axial extension (in extension of the axis of rotation of the drum) and an inner and an outer sheath, wherein the distance of the inner shell to the axis of rotation is not constant but expands or increases.

In this case, an annular gap is formed between the passage and an orifice plate outside the centrifugal drum or between the passage and another component, which directs the liquid radially outward and preferably wholly or partially over its axial extent away from the expanding deflection disc is surrounded, so that the direct radial ejection of the liquid phase is prevented from this annular gap. Especially here, the deflection disk has an advantageous effect, because it prevents the exiting liquid from hitting the drum again.

Preferably, the expanding baffle has an opening angle γ to a perpendicular to the axis of rotation D of the drum or parallel to the drum cover extending plane which is greater than 0 ° and smaller than 90 °. Thus, the expanding baffle on the inner shell at an angle 90 ° - γ to the axis of rotation (D) of the drum, which is greater than 0 ° and less than 90 °.

The baffle preferably has such a shape and is arranged or integrated into the arrangement such that the liquid first emerges axially outwardly of the drum until it strikes a wall or disk from which it spouts substantially radially outward, wherein it impinges on the expanding baffle, which prevents the exiting liquid directly radially on wall (s) - in particular aligned parallel to the axis of rotation walls - the catching chamber, so that the noise is reduced compared to a configuration without a deflecting disc.

The liquid initially enters axially - i. parallel to the axis of rotation of the drum - outwardly of the drum until it hits a wall from which it is directed substantially radially outwards. Here it meets the expanding baffle, which prevents the leaking fluid from getting back to the drum.

The expanding geometry of the baffle has several advantages. On the one hand, it makes it possible to significantly reduce the operating noise of the centrifuge, since the liquid is no longer injected directly from the annular gap, in particular between the throttle plate or other component and the drum lid against walls of the trap chamber but is deflected by an angle which the opening angle of the deflection disc equivalent. As a result, the liquid is no longer perpendicular to the housing walls of the catching chamber, what the noise significantly reduced. This is a great advantage in practice given the high RPM of eg 3500 RPM.

Due to the "gentler" impingement of a jet of liquid on the walls of the catching chamber foaming is also reduced in prone to foaming products.

Another advantage is a reduction in power consumption due to the initially rapid discharge from the inner region, in particular away from the centrifugal drum surface.

Preferably, the inner diameter of the baffle is larger than the outer diameter, on which the passage openings of the centrifugal drum are arranged.

Preferably, the baffle connects axially directly to the passage openings, so that leakage of liquid between the drum cover and the baffle is prevented. In a further advantageous variant, lugs or the like are provided at the passage openings - which axially overlap the deflection disk.

All other advantages of the generic state of the art described at the outset are otherwise retained.

In particular, the deflection disk has an annular, conically widening shape.

The opening angle of the inner jacket of the deflection disk is preferably between 5 and 45 °, in particular 10 to 30 °. Especially by the latter angular range can be particularly advantageous results, in particular a particularly significant noise minimization achieve.

The opening angle of the deflection disc may be constant or vary over the axial extent and / or in the circumferential direction.

It is also conceivable in particular a multi-part, in particular two-part design of the deflection plate in order to easily realize their widening shape.

Advantageous embodiments can be found in the dependent claims.

Fig. 1

einen Schnitt durch den axialen Endbereich einer erfindungsgemäßen Vollmantelzentrifuge mit einer Ablenkscheibe;

Fig. 2

eine Ausschnittsvergrößerung aus Fig. 1 mit einer vereinfachten beispielhaften Darstellung der Strömungsverhältnisse;

Fig. 3

einen Schnitt durch den axialen Endbereich einer zweiten erfindungsgemäßen Vollmantelzentrifuge;

Fig. 4

eine Ausschnittsvergrößerung aus Fig. 3 mit einer vereinfachten beispielhaften Darstellung der Strömungsverhältnisse;

Fig. 5

einen Schnitt durch den axialen Endbereich einer dritten erfindungsgemäßen Vollmantelzentrifuge nach Fig. 3 mit einer alternativen Art der Befestigung der Ablenkscheibe; und

Fig.6

einen Schnitt durch den axialen Endbereich einer dritten erfindungsgemäßen Vollmantelzentrifuge nach Fig. 3 mit einer weiteren alternativen Art der Befestigung der Ablenkscheibe.

The invention will be described in more detail below with reference to the drawing with reference to exemplary embodiments. It shows:

Fig. 1

a section through the axial end portion of a solid bowl centrifuge according to the invention with a deflection disc;

Fig. 2

an excerpt from Fig. 1 with a simplified exemplary representation of the flow conditions;

Fig. 3

a section through the axial end portion of a second solid bowl centrifuge according to the invention;

Fig. 4

an excerpt from Fig. 3 with a simplified exemplary representation of the flow conditions;

Fig. 5

a section through the axial end portion of a third Vollmantelzentrifuge invention after Fig. 3 with an alternative way of securing the baffle; and

Figure 6

a section through the axial end portion of a third Vollmantelzentrifuge invention after Fig. 3 with another alternative way of attaching the baffle.

Fig. 1 shows a Vollmantelzentrifuge trained as a solid bowl screw centrifuge with a rotatable centrifugal drum 1 with a horizontal axis of rotation. In the centrifugal drum 1, a likewise rotatable screw 2 is arranged, wherein in operation i.allg .. between the centrifugal drum 1 and the screw 2, a differential speed is maintained.

The centrifugal drum 1 is closed by an axial drum cover 3, which is provided with at least one - fixed or adjustable by means of diaphragms 13 - weir 4 for discharging a liquid phase from the centrifugal drum.

The weir 4 comprises a passage with at least one or more passage openings 5 in the drum cover 3 and with a throttle disk 6 arranged outside the centrifugal drum 3 in front of the passage openings 5, which is designed as a non-co-rotating part during operation and whose distance from the passage openings 5 is variable. Here is a collar-like projection 19 of the weir axially from the drum cover 3. This can be realized, for example, by by means of sleeves in / at the passage openings 5 or by means of a ring or a second diaphragm of a different diameter.

The changing of the axial distance between the passage openings 5 and the throttle disk 6 can be achieved, for example, by an axial movement by displacing or pivoting the throttle disk 6 in front of the passage openings 5, e.g. done by means of actuators. In that regard, the construction corresponds in principle to the generic state of the art.

Unlike in this prior art, the throttle plate 6 is associated with a ring-shaped deflection (or "deflecting") 12, which here has a particularly advantageous tapered shape, wherein the deflection plate 12 preferably covers the annular gap 8 over its entire length and expands away from the passage openings 5 away.

The opening angle γ of the inner shell 7 of the baffle 12 - see Fig. 2 - Relative to the perpendicular to the axis of rotation D of the drum or to a parallel to the drum cover extending plane E is preferably between 5 and 45 °, in particular between 10 ° and 30 °.

The opening angle γ is preferably constant over the entire radial and axial extent of the deflection disk 12. It may also change abruptly or continuously, e.g. at a crease of 15 to 20 °.

Since the flowing out of the annular gap 8 outward liquid to the deflection plate 12 and is deflected by this, it occurs substantially at an angle γ smaller than 90 ° against the walls 9, 10 of the throttle disc surrounding catch chamber 11 for liquid discharge. This results in a significant noise reduction during operation.

It is also conceivable in particular a multi-part, in particular two-part design of the baffle 12 in order to realize the widening shape of the baffle 12 constructively in a simple manner.

The optimized flow conditions are in Fig. 2 shown.

Good to see in particular the optimized discharge from the annular gap 8 while avoiding a direct leakage of the liquid phase L in the radial direction. The liquid thus no longer occurs on the wall 9 of the catching chamber, which extends substantially parallel to the axis of rotation. The noise development is thus significantly reduced, which, given the preferred - but not exclusive field of application - for drum diameters of much more than 500 mm is a clear advantage. Noise limits are more easily maintained or achieved only at higher speeds. Also, power losses are avoided if the liquid no longer hits the drum or the Lagemabe when it has leaked out of this.

In particular, the opening angle is selected such that the wall 9 is not reached directly outside of the catching chamber 11 from the exiting product jet.

A spiral housing geometry of the deflection disk 12, similar to the spiral housing of centrifugal pumps, is conceivable (not shown here).

To Fig. 3 Although the weir comprises the passage openings 5 in the drum cover 3 but no throttle disk 6. The liquid flows rather directly against another component - here an annular disk 14 in front of or on a transmission housing 18 - which is designed as non-co-rotating during operation part. The annular gap 8 ', which the deflecting disk 12 partially covers outwards here, is formed between the drum cover 3 and the further component annular disk 14.

The flow conditions are similar here to Fig. 2 optimized (see Fig. 4 ). The baffle 12 may also have a relative to the axial length of the annular gap 8 'greater extent than shown in the figures.

The attachment of the preferably made of sheet metal or sheets cheap manufactured baffle 12 can be done in various ways, so via bolts 15 or 16 in axial ( Fig. 1 and 3 ) or radial ( Fig. 5 ) Alignment which extend from surrounding walls 9, 10 or 10 to the baffle 12 or by means of a particularly advantageous stabilizing planar ring 17 between the outer jacket of the baffle 12 and the wall 9 (FIG. Fig. 6 ).

The arrangement of the fastening bolt or the fastening ring 17 in the radial direction reduces the risk of erosion thereof, since this is arranged quasi in the flow shadow of the baffle 12. The number of fastening bolts is variable and will usually be at least three. <U> reference numerals </ u> centrifugal drum 1 slug 2 drum lid 3 weir 4 passage opening 5 throttle disc 6 inner sheath 7 annular gap 8, 8 ' walls 9, 10 trap chamber 11 deflector 12 weir 13 washer 14 bolt 15, 16 ring 17 gearbox 18 approach 19

Claims (19)

1. Solid-bowl centrifuge, in particular a solid-bowl screw-type centrifuge, comprising

   a) a centrifugal drum (1) rotatable about a horizontal axis of rotation,

   b) which centrifugal drum has a weir for discharging a liquid from the centrifugal drum (1),

   c) which weir has a passage with at least one or more passage openings (5) in an axial end region or drum cover (3),

   characterized in that

   d) there is arranged in front of the drum cover (3) and outside of the centrifugal drum (1) a deflection disc (12) which is stationary during operation, widens at least in certain portions away from the drum cover (3) and has an inner jacket whose distance from the axis of rotation is not constant but widens or increases, wherein

   e) an annular gap (8, 8') is formed between the passage (4) and a throttle disc (6) outside of the centrifugal drum or between the passage (4) and another component and is preferably completely or partially surrounded over its axial extent by the widening deflection disc (12).
2. Solid-bowl centrifuge according to Claim 1, characterized in that the widening deflection disc (12) has at the inner jacket (7) an opening angle γ with respect to a plane (c) extending perpendicularly to the axis of rotation (D) of the drum or parallel to the drum cover (3), which opening angle is greater than 0° and less than 90°.
3. Solid-bowl centrifuge according to either of the preceding claims, characterized in that the deflection disc has an annular, conically widening shape.
4. Solid-bowl centrifuge according to one of the preceding claims, characterized in that the liquid first passes axially outwardly from the drum until it strikes a wall or disc from which it sprays substantially radially outwardly and strikes the widening deflection disc, which prevents the exiting liquid from directly radially striking the wall(s) (9) of the collection chamber, with the result that the generation of noise is reduced.
5. Solid-bowl centrifuge according to one of the preceding claims, characterized in that the widening deflection disc (12) has at the inner jacket (7) an angle 90°-γ to the axis of rotation (D) of the drum which is greater than 0° and less than 90°.
6. Solid-bowl centrifuge according to one of the preceding claims, characterized in that the inner smallest diameter of the deflection disc (12) is greater than the outer diameter on which the passage openings (5) are arranged.
7. Solid-bowl centrifuge according to one of the preceding claims, characterized in that the deflection disc axially directly adjoins the passage openings (5).
8. Solid-bowl centrifuge according to one of the preceding claims, characterized in that a projection (19) which protrudes axially from the drum cover and which is overlapped axially by the deflection disc (12) is formed on the passage openings (5).
9. Solid-bowl centrifuge according to one of the preceding claims, characterized in that the opening angle (γ) of the deflection disc (12) is between 5 and 45°.
10. Solid-bowl centrifuge according to Claim 9, characterized in that the opening angle (γ) of the deflection disc (12) is between 10 and 30°.
11. Solid-bowl centrifuge according to one of the preceding claims, characterized in that the opening angle (γ) of the deflection disc (12) is constant.
12. Solid-bowl centrifuge according to one of the preceding Claims 1 to 10, characterized in that the opening angle (γ) of the deflection disc (12) varies over its axial extent and/or in the circumferential direction.
13. Solid-bowl centrifuge according to Claim 11, characterized in that the opening angle (γ) of the deflection disc (12) varies continuously or abruptly, in particular increases, over the axial extent of the deflection disc (12).
14. Solid-bowl centrifuge according to one of the preceding claims, characterized by a multi-part, in particular two-part, configuration of the deflection disc (12).
15. Solid-bowl centrifuge according to one of the preceding claims, characterized in that the distance between the passage (4) and the throttle disc (6) is variable.
16. Solid-bowl centrifuge according to one of the preceding claims, characterized by a configuration as a solid-bowl screw-type centrifuge having a rotatable screw (2) arranged in the centrifugal drum (1).
17. Solid-bowl centrifuge according to one of the preceding claims, characterized in that the deflection disc (12) is fastened to a surrounding wall (9, 10) via bolts (15 or 16) in an axial orientation.
18. Solid-bowl centrifuge according to one of the preceding claims, characterized in that the deflection disc (12) is fastened to a surrounding wall (9, 10) via bolts (15 or 16) in a radial orientation.
19. Solid-bowl centrifuge according to one of the preceding claims, characterized in that the deflection disc (12) is fastened to a surrounding wall (9, 10) via a ring (17).

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