EP1998896B1 - Fully jacketed screw centrifuge with efflux orifices for partial and residual emptying of the drum - Google Patents

Description

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

Solid bowl centrifuges are known in various embodiments. When the drum is leaking, the liquid ring in the drum breaks down below a limit speed, so that the residual liquid collects at the bottom of the drum. In order to carry out a complete emptying of the residual liquid still remaining or to prevent emptying on the solid side or the liquid side, it is known to derive the residual liquid through separate drain holes, in which in the generic DE 41 30 759 A1 For example, spring-loaded valves or valves are used.

The prior art is also the DE 36 209 12 mentioned, in which it is proposed to realize the liquid discharge solely through openings in the drum shell, which are associated with cone-like adjusting members, which are each actuated by means of separate piston-cylinder units or sliders. Other constructions of the prior art disclose the DE 39 11 320 A1 and the DE 37 28 901 C1 ,

The constructions described above are relatively expensive and prone to malfunction. Their simplification is therefore the object of the invention.

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

According to the characterizing part of claim 1, the at least one or more further outflow opening (s) is associated as closure means a relative to the drum axis axially displaceable, in-line with the drum co-rotating ring, which is associated with an actuator, with which the ring in a the Outlet opening (s) opening position and this - completely - closing position is displaceable. This design is easy to build and is particularly reliable, because it dispenses with fault-prone valve technology or single slide.

At the same time, it also makes it possible to open and close all emptying or outlet openings with only one single actuating device. With CIP (Cleaning-In-Process) applications, the drum does not need to be shut down beforehand because the CIP program can be started directly after emptying while the drum is still rotating or even without reducing the speed.

When driving down an undesirable emptying is - in particular to the solid side - avoided in a simple manner. When the liquid level collapsed due to increasing speed reduction, however, in the prior art u.U. a spillover of liquid through the barrel of the drum. Fluid vibrations when stopping the drum are also avoided.

The state of the art is also the DE 102 09 025 A1 called in Fig. 4 discloses a ring axially displaceable outside of a drum opening, but which can not close the opening, since its outer circumference is greater than the outer circumference of the drum in this area, that there is always a gap between the drum and ring elements. In the invention, however, the ring completely closes the drainage openings, since the inner diameter of the preferably circumferentially closed ring and the outer diameter of the drum are coordinated accordingly.

Preferably, the actuating device is designed as a fluidic, in particular hydraulic actuator. Such an actuator builds compact, is particularly reliable and relatively easy to implement on the rotating drum.

According to a particularly simple and cost-effective variant, the outflow openings are formed as openings, in particular holes or slots in the drum shell of the drum. The latter variant lends itself to carry out particularly effective also a solid phase, as the slots one may have relatively large cross-section. The elongated holes preferably extend in the circumferential direction.

According to a further advantageous embodiment, the discharge openings are arranged axially in front of the continuously acting liquid discharge, which takes place in particular by means of a paring disc or by means of further openings in the drum lid.

It is particularly advantageous if the drain openings are formed in the drum shell of the drum so that they lie radially outside of a separation and / or Klärtellerpaketes of plates, wherein the Klärtellerpaket is connected upstream of the continuous liquid discharge. Plate packages in decanters are eg from the DE 100 65 060 A1 known.

Especially in this area, the supplemental drainage holes are particularly useful because they can be used not only for draining a residual liquid level but also for partial draining (e.g., a partial volume of 101) during full speed production or processing.

Alternatively, an arrangement of the drainage openings in the drum cover can be realized.

Thus, especially in operation with still rapidly rotating drum, a derivative of flowable solid or product, which has accumulated on the inner circumference of the drum shell in this axial region of the drum, possible.

Known to foreign invaders, self-cleaning drum separators are known, so from the DE 38 21 486 A1 or the DE 38 29 158 A1 , the ring slide for closing of Feststoffaustragsöffnungen have. In contrast, in a decanter according to the invention, additional discharge openings are now provided which do not replace the continuous solids discharge openings at the conical end of the drum, but rather supplement it, in particular in order to simplify emptying of the drum.

Further advantageous embodiments can be found in the remaining subclaims.

• Fig.1 eine Ausschnittansicht einer ersten Vollmantel-Schneckenzentrifuge in einer ersten Betriebsstellung:
• Fig.2 eine Ausschnittansicht einer zweiten Vollmantel-Schneckenzentrifuge;
• Fig. 3 die Vollmantel-Schneckenzentrifuge aus Fig. 2 in einer zweiten Betriebsstellung;
• Fig.4 eine Ausschnittansicht einer dritten Vollmantel-Schneckenzentrifuge in einer ersten Betriebsstellung: und
• Fig.5 eine bekannte Vollmantel-Schneckenzentrifuge.

The invention will be explained in more detail with reference to an embodiment. It shows:

• Fig.1 a cutaway view of a first solid bowl screw centrifuge in a first operating position:
• Fig.2 a detail view of a second solid bowl screw centrifuge;
• Fig. 3 the solid bowl screw centrifuge Fig. 2 in a second operating position;
• Figure 4 a cutaway view of a third solid bowl centrifuge in a first operating position: and
• Figure 5 a known solid bowl centrifuge.

Fig. 5 shows a solid bowl screw centrifuge with a rotatable about a horizontal axis of rotation drum 1, which has a cylindrical portion 2 and a tapered portion 3. In the drum 1, a rotatable screw 4 is arranged, wherein the design and operation is such that the drum 1 and the screw 4 during operation have a - usually relatively low - differential speed. The drum bearing bears the reference number 26.

The solid bowl screw centrifuge serves to separate at least one solid phase and one or more liquid phases into a product passed through an inlet pipe 5 and a distributor 6 into the centrifugal space 7 in the drum 1. Due to the density difference, the solid phase accumulates outside in the drum 1, from where it is continuously conveyed from the drum 1 in the direction of a solids discharge 8 at the tapering end of the drum 1 and through the solids discharge 8.

By contrast, the at least one liquid phase is continuously discharged at the opposite end of the drum by at least one liquid discharge.

This liquid discharge can in a generic drum on the type of Fig. 5 be realized according to the invention in various ways. Such constructions, the one at a decanter, which otherwise the the Fig. 5 can be used, the show Fig. 1 to 4 ,

Thus, a drum cover 14 closing the drum 1 at the cylindrical end generally has at least one weir-like passage opening 9 which forms the liquid discharge (indicated in FIG Fig. 2 and 3 ). But it is also a derivative in another form, for example by a paring disc 22 ( Fig. 1 ) possible. If several liquid phases are to be discharged, these are removed by liquid outlets at different radii of the centrifugal space 7. The liquid discharge takes place continuously.

The centrifuge of Fig. 1 has in addition or modification of the known construction of Fig. 5 further - here advantageously circumferentially distributed on the outer circumference of the drum shell - discharge openings 10, which is associated with a closure device, which makes it possible to open the drain openings during operation of the drum 1 and to close. Preferably, at least two, in particular four or more, of the discharge openings 10 are distributed around the circumference.

The fact that the discharge openings 10 are formed and distributed directly in the drum shell 15, has the advantage that they can be easily formed as breakthroughs in this component and that not a guide of drainage channels through the drum cover 14 is necessary.

The closure device for the discharge openings 10 is after Fig. 1 formed in a simple constructive design as a cylindrical ring 11 which rotates during operation with the drum 1 and which is guided axially displaceably on the drum cover 14 and / or connected to the drum cover member.

In this way, a discontinuous or only in the corresponding case of operation to be realized liquid discharge from the drum 1 can be achieved.

The discharge openings 10 are formed axially just before the drum cover 14 facing end portion of the drum shell. The drum shell has at its axial end in front of the drum cover 14 on a radially projecting collar 15 which is provided with a gradation 12. To Fig. 1 to 3 the outflow openings are advantageously formed in this area.

The ring 11 is guided here displaceably on the outer circumference of the drum cover 14.

Since the ring 11 rotates during operation with the drum 1, it is necessary to be able to move it axially in operation in a simple manner. This is preferably effected fluidically, in particular hydraulically.

To Fig. 1 For this purpose, in the drum cover 14 an exemplified, advantageous hydraulic chamber 13 is formed, in which an inner, preferably disc-like, radial projection 16 of the ring 11 extends into, so that on one side of the neck 16 an opening chamber 13a (here left of the approach) and on the other side of the approach forms a closing chamber 13b. The opening chamber has a larger radial extent than the closing chamber 13b.

The projection 16 extends radially from outside to inside into the hydraulic chamber 13. Radially inwardly, the opening chamber 13a and the closing chamber 13b are operatively connected.

In the closing chamber 13b opens a hydraulic line 17, which passes through the drum cover 14 and possibly subsequent thereto rotating parts 23 and which opens into an annular chamber 24, in whose area a transition to a supply line 18 at the non-rotating supply pipe 5 is realized.

Ribs 28 are arranged in the annular chamber 24 in order to take along the fluid, in particular water, which passes from the feed line 18, which is not rotating during operation, into the rotating annular chamber 24.

Through a nozzle-like opening 25, which leads out of the drum out of the opening chamber 13a, the hydraulic fluid is discharged from the opening chamber 13a.

In an operating position, the ring 11 rests against the step 12 and closes the drainage openings 10 (Fig.l; Fig. 2 ). In the other operating position, however, he releases them ( Fig. 3 ), so that liquid is discharged from the drum through these further drainage openings 10.

• Strömt Fluid (vorzugsweise Wasser) durch die Zuleitung 18 und tritt in die Ringkammer 24, wird es von den Rippen 28 in Umfangsrichtung mitgenommen und strömt in der Hydraulikleitung 17 nach außen bis in die Hydraulikkammer 13, wo es sich aufgrund der Rotation der Trommel in der Schließkammer 13b sammelt, so dass der Ring 11 aufgrund des auf den Ansatzes in die linke Richtung - also in die Schließstellung gedrückt wird.

The function of the hydraulic chamber 13 is as follows:

• Flows fluid (preferably water) through the supply line 18 and enters the annular chamber 24, it is entrained by the ribs 28 in the circumferential direction and flows in the hydraulic line 17 to the outside to the hydraulic chamber 13, where it due to the rotation of the drum in the Closing chamber 13b collects, so that the ring 11 is pressed due to the on the approach in the left direction - ie in the closed position.

If further water is passed into the hydraulic chamber 13, it finally passes into the opening chamber 13a. If this is filled, the force on the projection 16 to the right - ie in the open position - greater than the force in the closed position, so that the ring 11 moves to the right in the open position.

When the water supply is stopped in the open position, the water flows through the opening 25 from the opening chamber 13 a from. By contrast, water remains in the closing chamber 13b due to the rotation of the drum, which displaces the ring in the closed position.

With a high level of functional reliability, precise and fast, defined actuation is thus possible in a simple manner, which represents a major advantage over the prior art. There is also the advantage that with only one component - the ring 11 - across all drain openings 10 can be opened or closed.

A seal 27 in a groove in the step 12 seals the gap between the ring 11 and the drum in the closed position safely.

In the area facing away from the drum, the hydraulic chamber 13 is closed by a ring 19 fastened on the drum cover 14, which also allows the mounting of the ring 11. Such a ring 19 is also found in Fig. 2 and 3 , The illustrated hydraulic chamber 13 is compact and simple. It could alternatively be realized in other constructive ways, as far as it realizes the required function.

The ring 11 of Fig. 1 to 3 rotates with the drum 1, since he must be able to completely close the discharge openings 10. He also lies directly outside on the drum 1 and the drum cover 14.

There are therefore seals 29, 30 arranged on the outer circumference of the drum and the ring 19 to the inner periphery of the ring 11, so that substantially no fluid can escape through the gap between the ring and the drum or the drum cover and the ring 19.

There is also a sealing ring 31 between the drum cover 14 and the drum 1 and there is a sealing ring 32 between the ring 19 and the drum cover 14. Also between the drum cover 14 and the part 23, a sealing ring 33 is disposed around the hydraulic line 17 around. Additional seals 35, 36 can be found inside the paring disc.

To Fig. 1 the drum lid is internally conical. In this area could optionally be a separation and / or Klärtellerpaket from plates (not shown here), as it is known from DE 10065 060 is known.

In this case, the drainage openings 10 are then preferably formed in the drum shell of the drum 1 so that they lie radially outside of the separation and / or Klärtellerpaktes, the screw 4 nach- and the liquid discharge 9 is connected upstream.

In this way, the discharge openings 10 can also be used for the discharge of product and / or solid, which is located on the inner circumference of the drum shell has accumulated in this axial region of the drum. In this case, the outflow openings 10 can also be located radially outside the screw 4 (not shown here).

It is also advantageous that the drum cover is internally conical, so that on its outer peripheral contour is a very good possibility to accommodate the mechanism or here the hydraulic system for moving the ring 11.

It is also conceivable that the hydraulic chamber has an opening chamber and that one or more spring elements are provided for generating the closing force on the ring (not shown).

An alternative embodiment still shows Fig. 4 , The structure of this embodiment largely corresponds to that of Fig. 1 , In contrast to Fig. 1 However, it is provided that the discharge openings 10 are still formed in the drum cover 14.

The outer contour of the drum 1 with the drum cover 14 as a whole does not change as a result, because only the contact area or the "interface" between the drum cover 14 and the drum 1 shifts: The drum 1 ends axially here before the drain openings 10th

The discharge openings 10 are formed axially in the end facing the drum 1 of the drum cover 14. The drum cover 14 also has, at its axial end in front of the drum 1, preferably a radially projecting collar 37, which is provided with the step 12 and here outwardly aligned with the collar 15 of the drum 1. The ring 11 is in turn guided displaceably on the outer circumference of the drum cover 14 here.

At the step 12 of the ring 11 is in the closed position. This version provides the functionality of the embodiment of Fig.1 , In the production here no drain openings 10 must be incorporated into the outer circumference of the drum 1. <B> reference numerals </ b> drum 1 cylindrical section 2 Rejuvenating section 3 slug 4 supply pipe 5 distributor 6 centrifugal chamber 7 solids 8th Port 9 drain openings 10 ring 11 gradation 12 hydraulic chamber 13 opening chamber 13a closing chamber 13b drum lid 14 Federation 15 radial approach 16 hydraulic line 17 supply 18 ring 19 peeling disc 22 rotating parts 23 annular chamber 24 opening 25 drum bearing 26 poetry 27 ribs 28 Gaskets / seals 29 - 33, 35 - 36 Federation 37

Claims (19)

1. Solid-bowl screw centrifuge, having a drum (1) with a drum lid (14) which can rotate about a preferably horizontal axis of rotation and in which is arranged a rotatable screw (4), and having a continuous solids discharge (8) at one end of the drum (1) and having a continuous liquid discharge at the opposite end of the drum (1), and having at least one or more further, discontinuously acting outlet opening(s) (10) provided with a closure device, characterized in that the at least one or more further outlet opening(s) (10), as closure device, is/are assigned a ring (11), which can be axially displaced relative to the drum axis, rotates with the drum (1) in operation and is assigned an actuating device, by means of which the ring can be displaced into a position which opens up the outlet opening(s) (10) and a position which closes said opening (s), wherein the ring (11) is guided displaceably on the outer circumference of the drum lid (14).
2. Solid-bowl screw centrifuge according to claim 1, characterized in that the actuating device is designed as a fluidic actuating device.
3. Solid-bowl screw centrifuge according to claim 2, characterized in that the actuating device is designed as a hydraulic actuating device.
4. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the outlet openings (10) are formed as apertures, in particular drilled holes or slots, in the lateral surface of the drum (1).
5. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the outlet openings (10) are arranged axially before the continuously acting liquid discharge.
6. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the outlet openings (10) are formed in the lateral surface of the drum (1) in such a manner that they lie radially outside a separation and/or clarification disk set made up of disks, with the clarification disk set connected upstream of the continuous liquid discharge (9).
7. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the outlet openings (10) lie radially outside the screw (4).
8. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the outlet openings (10) are formed in that end region of the drum lateral surface which faces the drum lid (14).
9. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the drum lateral surface, at its axial end before the drum lid (14), has a radially protruding collar (15), which is provided with a step (12), and in that the outlet openings (10) are formed in the region of said step (12).
10. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that a hydraulic chamber (13) is formed on or in the drum lid (14).
11. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the drum lid is of internally conical design, and in that the hydraulic chamber (13) is formed at its outer circumference.
12. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the hydraulic chamber (13) has an opening chamber and a closure chamber (13a, 13b), which are operatively connected.
13. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the hydraulic chamber (13) has an opening chamber (13), and in that one or more spring elements are provided for the purpose of generating the closure force.
14. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that an inner, preferably disk-like radial attachment (16) of the ring (11) extends into the hydraulic chamber (13), with a hydraulic conduit (17) opening out into the hydraulic chamber (13).
15. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the hydraulic conduit (17) passes through the drum lid (14) and any adjoining parts and is operatively connected to a hydraulic conduit (18) on the non-rotating feed pipe (5).
16. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the hydraulic chamber (13), in its region remote from the drum, is closed by a ring (19) secured to the drum lid (14).
17. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the opening chamber (13a) has a nozzle-like opening (25), which leads outward from the hydraulic ring chamber (13) out of the drum in order to discharge hydraulic fluid from the hydraulic chamber.
18. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the outlet openings (10) are formed in the drum lid (14).
19. Solid-bowl screw centrifuge according to one of the preceding claims, characterized in that the drum lid (14) has a radially projecting collar (37) that is provided with the step (12).

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