EP2394030A2

EP2394030A2 - Steam strainer and method for producing a steam strainer

Info

Publication number: EP2394030A2
Application number: EP10704342A
Authority: EP
Inventors: Rüdiger BACKASCH
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2009-02-03
Filing date: 2010-01-29
Publication date: 2011-12-14
Also published as: WO2010089250A3; DE102009007240A1; WO2010089250A2

Abstract

The invention relates to a steam strainer (10) having a sieve surface (12) of a substantially cylindrical or conical design (16) and having a plurality of sieve openings (14) for the radial pass-through of steam. In order to enable a comparably low flow resistance in such a steam strainer (10), the sieve surface (12) is corrugated according to the invention. As a result of the corrugation of the sieve surface (12), the area effectively available for straining the steam is enlarged, allowing the flow resistance to be reduced. The invention further relates to a method for producing such a steam strainer (10).

Description

description

Steam sieve and method for producing a steam sieve

The present invention relates to a vapor sieve and to a process for producing a vapor sieve. Furthermore, the invention relates to the use of such a vapor sieve.

Steam sieves are required, for example, in steam turbine plants in order to expel foreign bodies in the steam exhaust ducts, which could otherwise damage the rotor blades and guide vanes of the steam turbine in question.

In a common embodiment, the vapor sieve has a sleeve-like shape with a cylindrical or conical screen surface, which is traversed by the vapor in the radial direction. Such known steam strainers are described, for example, in DE 1 184 355 and DE 1 198 833.

A disadvantage is the use of steam screens known

Design often the concomitant increase in the flow resistance of the relevant steam line passage.

To reduce this flow resistance and thus to minimize flow losses, it is possible to use a particularly large-sized steam sieve. The disadvantage here, however, especially the correspondingly increased space requirement. It should be noted that steam sieves are often provided for installation in installation environments with more or less fixed or limited space. In a steam turbine plant, for example, steam sieves are often structurally integrated in the housing of a steam valve, which serves to control a steam flow of the system.

It is an object of the present invention to provide a vapor sieve in which a comparatively low flow resistance is made possible. According to the invention this object is achieved by a vapor sieve according to claim 1 and a process for producing a vapor sieve according to claim 8 or 9. The dependent claims relate to advantageous developments of the invention, which may be provided individually or in combination. The developments of the vapor sieve can be used in an analogous manner for further development of the manufacturing process.

In the vapor sieve according to the invention, a screen surface of substantially cylindrical or conical shape and with a plurality of screen openings for the radial passage of steam is provided, wherein the screen surface is corrugated.

The corrugation or unevenness of the sieve surface has the consequence that the area effectively available for sieving the vapor is increased, for example, in particular larger than a contour circumscribed by the vapor sieve (eg cylinder or cone). In other words, the vapor sieve has a larger screen area compared to an ideal cylindrical or conical shape.

In a preferred embodiment, it is provided that the screen surface is larger by at least a factor of 1.5, preferably by at least a factor of 2, than the cylinder or conical surface circumscribed by the screen surface.

In one embodiment, it is provided that the screen surface is corrugated in the circumferential direction of the vapor sieve.

Alternatively or additionally, it may be provided that the screen surface is corrugated in the axial direction.

In one embodiment, it is provided that the screen surface is corrugated or zigzag-shaped corrugated. These special types of corrugation can in principle also be be provided in the circumferential direction and / or in the axial direction.

For manufacturing reasons, an embodiment is preferred in which substantially the entire screen surface is corrugated in a uniform manner, ie, for. B. over the entire screen surface in the circumferential direction and / or axial direction.

However, it should not be excluded that the screen surface is composed of Siebflächenabschnitten that are corrugated in different ways, ie z. B. with a circumferentially corrugated Siebflächenabschnitt and another, corrugated in the axial direction section.

In general, however, it is preferable to provide the substantially entire screen surface in a uniform manner corrugated.

In one embodiment, it is provided that the steam sieve comprises a plurality of screen plates, which are lined up in a zigzag manner in the circumferential direction of the vapor sieve annularly and connected to each other. This can be done in manufacturing technology simple way a corrugated in the circumferential direction of the screen surface (or Siebflächenabschnitt). Advantageously, this can be used without further identical screen plates, z. B. may have an identical rectangular contour (to produce, for example, a steam sieve with a cylindrical shape).

Alternatively or additionally (preferably alternatively), it may be provided that the vapor sieve comprises a plurality of sieve plate rings, which are lined up in the axial direction of the vapor sieve and connected to each other, wherein at least a portion of the sieve plate rings forms sheet metal surfaces oriented obliquely to the axial direction. In this way, a sieve surface (or screen surface section) which has been corroded in the axial direction can be produced in a simple manufacturing technology. gen. Advantageously, z. B. identical screen plate rings are used, for. B. annular metal rings with approximately V-shaped profile cross-section, wherein the "tip of the V" in the radial direction (pointing radially inward or radially outward send) is oriented.

The screen plates or screen plate rings required in the embodiments described above are preferably made of a metallic material (eg steel). The connection fertil of the screen plates or screen plate rings with each other can, for. B. may be provided as a weld, gluing, screwing etc.

In a most preferred embodiment, all screen plates or screen plate rings on the finished steam sieve are each provided with screen openings for the passage of steam. In screen plates provided with screen openings or Siebblechringen can be provided that the screen openings claim at least 40% of the respective sheet metal surface.

If the vapor sieve is composed of a plurality of vapor sieve components, which each form part of the sieve surface of the vapor sieve, as described, for example, in US Pat. B. is the case, in particular in the above-described embodiments with the screen plates or Siebblechringen, so it is generally preferred, the desired screen openings already in the manufacture of the steam sieve components of these (eg., By water jet cutting, laser cutting, milling, etc.) train. Particularly in the case of a highly corroded sieve surface on the finished steam sieve, in practice it tends to be rather difficult to subsequently form the openings.

There are many possibilities for the number, shape and orientation or arrangement of the sieve openings, of which one option which is particularly suitable in each individual case can be selected. In the method according to the invention for producing a vapor sieve, it is provided that a plurality of screen plates are lined up in a zigzag manner and connected to each other and / or that a plurality of screen plate rings are lined up in the axial direction and connected to each other, wherein at least a part of the screen plate rings obliquely to the axial direction has oriented sheet surfaces.

The vapor sieve according to the invention or a vapor sieve produced according to the invention can for example represent a component of a steam valve and / or be used in a steam turbine plant.

The invention will be further described by means of embodiments with reference to the accompanying drawings. They show:

1 is a schematic plan view of a vapor sieve according to a first embodiment,

2 is a schematic side view of a vapor sieve according to a second embodiment,

3 is a perspective view of a vapor sieve according to a third embodiment,

4 shows a radial section through the vapor sieve of FIG. 3, FIG.

5 is a perspective view of a vapor sieve according to a fourth embodiment,

Fig. 6 is an axial section through the steam sieve of

Fig. 5,

Fig. 7 is a perspective (partially sectioned) view of a vapor sieve according to a fifth embodiment, and 8 and 9 are perspective (partially sectioned) views of a z. Example, for the production of the steam screens shown in Figs. 5 to 7 usable screen plate ring, wherein Fig. 8 represents an intermediate product and Fig. 9 the finished screen plate ring.

Fig. 1 illustrates a vapor sieve 10 having a screen surface 12 of substantially cylindrical shape and having a plurality of screen openings 14 for the radial passage of steam. By the arrows in Fig. 1, such a steam passage from the outside inwards is symbolized by way of example. Deviating from this, the steam sieve 10 could also be used as a sieve in the radial direction from inside to outside.

A peculiarity of the steam sieve 10 is that the screen surface 12 does not extend in the circumferential direction exactly along the "ideal" cylindrical shape 16 shown in FIG. 1, but is corrugated in the circumferential direction to increase the effective screen area.

In the illustrated embodiment, the screen surface 12 is zigzag corrugated in the circumferential direction, whereby the screen surface 12 is larger by about a factor of 2 than the cylinder surface 16 circumscribed by the screen surface 12.

When using the steam sieve 10 in an installation environment, which provides a defined by the cylinder shape 16 space for the steam sieve 10, thus advantageously results in a reduced flow resistance and thus lower flow losses compared to a similar sized conventional steam sieve with a smooth (cylindrical) screen surface.

In the illustrated embodiment, the screen surface 12 30 outwardly directed teeth (and accordingly also 30th inwardly directed teeth). This number of teeth is of course to be understood only as an example and can be varied in practice. For many applications is low z. B. a preferably evenly distributed over the circumference te number of bulges (and corresponding indentations) of at least 20, for example in a range of 20 to 100.

Of course, the shape and dimensioning of the bulges and indentations (in relation to the diameter of the steam sieve) can be varied in practice, as long as this is accompanied by a noticeable increase in the effective sieve area. In this regard, the corrugation of the screen surface 12 could instead of zigzag also z. B. wave-shaped or otherwise (with at least partially not exactly in the circumferential direction extending surface portions) may be provided.

In the following description of further exemplary embodiments, the same reference numbers are used for equivalent components, in each case supplemented by a small letter to distinguish the embodiment. In this case, essentially only the differences from the embodiment (s) already described are discussed and, moreover, reference is hereby explicitly made to the description of previous exemplary embodiments.

Fig. 2 illustrates a steam sieve 10a having a screen surface 12a which, as in the first embodiment, is again provided with a plurality of screen openings 14a for the passage of steam and has an overall substantially cylindrical shape 16a.

In order to increase the effective screen area, however, the screen surface 12a, unlike the first exemplary embodiment, is not corrugated in the circumferential direction but in the axial direction. As in the first embodiment, this zigzag-like "folding" of the outer surface of the steam strainer 10a again results in an advantageous minimization of the flow losses when using the steam strainer.

The screen surface 12a has in the illustrated embodiment 12 radially outwardly directed teeth, plus two "half teeth" at the two ends of the vapor sieve 10a, and accordingly 13 radially inwardly directed teeth. The number, shape and dimensioning of these prongs can again be adapted to the specific application.

In the embodiments described above with reference to FIGS. 1 and 2, the screen surfaces 12 and 12a can each be formed from a workpiece or formed by a composition of a plurality of workpieces.

FIG. 3 shows a steam sieve 10 b according to a further exemplary embodiment, in which a multi-part screen surface 12 b is corrugated in the circumferential direction.

A peculiarity of the steam sieve 10b is that, to form the sieve surface 12b, a plurality of sieve plates 20b having the sieve openings 14b are lined up in a zigzag manner in the circumferential direction in a ring shape and are connected to one another.

In the exemplary embodiment illustrated, the individual screen plates 20b were each made of a metallic material (eg, steel sheet with a thickness of approximately 2 to 8 mm), wherein the screen openings 14b were already formed during this production (eg laser-cut). The screen openings 14b occupy about 50% of the respective screen plate surface and are preferably provided (as shown) as elongated, mutually parallel slots (slot width, for example, in the range of a few mm, slot length, for example, a few cm). Age- natively could also be a breadboard arrangement z. B. circular holes can be provided.

The connection of adjacent screen plates 20b is accomplished in the illustrated embodiment by a weld on the axially extending plate edges.

In addition, the steam sieve 10b at the axial end faces also comprises end rings 22b and 24b, which are also made of a metallic material and connected by welding to the screen plates 20b. As an alternative to the rings 22b and 24b shown here as open rings, one of these termination components could also be "closed" as a cover plate.

FIG. 4 is a radial sectional view of the vapor sieve 10b and again clearly shows the corrugation of the sieve surface 12b in the circumferential direction. It is clear that the simple rectangular contour of the individual screen plates 20b represents a particularly easy way of realizing the "folding" of the screen surface 12b in practice. Deviating from this, however, it is also possible to use screen plates with a different shape design, in particular non-planar plates.

5 shows a steam sieve 10c according to a further embodiment, in which a sieve surface 12c with slot-shaped sieve openings 14c is corrugated in the axial direction.

As in the embodiment according to FIGS. 3 and 4, the screen surface 12c is made up of a plurality of prefabricated components, which were already provided with the screen openings 14c during their production.

These components are a plurality of identically formed screen plate rings 30c each having a conical shape, which, for. B. made of a steel material and are connected to the finished steam sieve 10c by welding together. For the end-side termination of the construction at the axial ends, planar end rings 22c and 24c are again provided and connected to the respectively adjacent screen plate rings 30c.

Fig. 6 shows the juxtaposition of the individual screen plate rings 30c and the end rings 22c and 24c again in an axial sectional view. It can be seen that in the illustrated embodiment 16 identical screen plate rings 30c are lined up in an alternating orientation in the axial direction. At the contact points of the screen plate rings 30b with each other and to the end rings 20c and 24c towards these steam sieve components are welded together.

For the production of the screen plate rings 30c could be used as semi-finished z. For example, serve metal tube from which individual pipe sections are separated and subsequently processed further, such as by punching or other mechanical or thermomechanical methods (eg., Water jet cutting, laser cutting, etc.) z. B. slot-shaped screen openings 14c are introduced and the individual rings each conical shape is awarded.

In this way could also differ from the illustrated

Embodiment screen mesh rings are produced, which are identically dimensioned at their axial end faces (eg., Annular with identical diameter), but between them are designed to form a corrugation (as viewed in the axial direction varying diameter). An example of such a screen plate ring would be z. B. a circular ring with a V-shaped cross section (with the tip of the V radially inward or radially outward). In terms of shape, this would correspond to a combination of two screen plate rings 30c shown in FIG. When using such V-profiled screen metal rings, the number of required welds would be approximately halved. FIG. 7 shows a steam sieve 10d (partial sectional view) according to a further embodiment.

In contrast to the exemplary embodiment according to FIGS. 5 and 6, in the vapor sieve 10d conical sieve plate rings 30d are not lined up in an alternating orientation in the axial direction, but such conical sieve plate rings 30d are lined up alternately with flat sieve plate rings 30d 'in the axial direction. The surface of the flat rings 30d 'is in this case oriented in the radial direction of the vapor sieve 10d. The connection of the components 30d and 30d 'may, for. B. be realized again by a weld. In this exemplary embodiment too, a screen surface 12d which is zigzag-shaped in the axial direction results. However, unlike the examples of this type of corrugation explained above, the screen surface 12d does not have a radial plane of symmetry. The zigzag form of corrugation is here "sawtooth-shaped".

In the illustrated embodiment, screen openings 14d are introduced only in the conical screen plate rings 30d, but not in the flat screen plate rings 30d '. Due to this peculiarity, the radial passage of steam through the screen surface 12d inevitably results in a certain directional effect in the corresponding axial direction. If the steam sieve 10d, for example, flows through from the outside to the inside, then the steam flowing out on the inside of the sieve surface 12d is directed axially downwards in FIG. 7, which can be advantageous in the case of a removal of the vapor in this direction (eg B. to reduce internal turbulence).

The connection of the individual screening sheet metal rings required in the exemplary embodiments according to FIGS. 5 and 6 as well as in FIG. 7 can also be achieved by means of a suitable shaping

Plug connection be accomplished, so that if necessary can be dispensed with a welding at this point. To secure such a connector (or even to replace them), axial clamping of the stack of screen plate rings formed in the axial direction can also be provided, for example by a screw connection, by means of which the two end-side termination components (eg components 22c and 24c in FIGS Final sieve plate rings 3Od 'in Fig. 7) in the axial direction to each other to be loaded or secured.

Figs. 8 and 9 illustrate a conceivable manner of manufacturing a screen plate ring 30e (Fig. 9), e.g. B. for the steam strainers according to FIGS. 5 to 7 can be used.

Fig. 8 shows (partially cut) an intermediate product 32e of this production, namely a sheet metal circular ring 32e, the z. B. was provided by separation from a corresponding metal tube and subsequent introduction of screen openings 14e.

From this intermediate product 32e, the screen plate ring 30e shown in Fig. 9 was then produced by finishing (e.g., turning).

Claims

claims

A steam sieve having a sieve surface (12) of substantially cylindrical or conical shape (16) and having a plurality of sieve openings (14) for the radial passage of steam,

That is, the screen surface (12) is corrugated.

2. Steam sieve according to claim 1, wherein the screen surface (12) by at least a factor of 2 larger than that of the screen surface

(12) circumscribed cylindrical or conical surface (16).

3. Steam sieve according to one of the preceding claims, wherein the screen surface (12) is corrugated in the circumferential direction of the vapor sieve (10).

4. Steam sieve according to one of the preceding claims, wherein the screen surface (12) is corrugated in the axial direction of the vapor sieve (10).

5. Steam sieve according to one of the preceding claims, wherein the sieve surface (12) is wavy or zigzag kor- rugiert.

6. Steam sieve according to one of the preceding claims, comprising a plurality of screen plates (20) which zigzag in the circumferential direction of the vapor sieve anei- nested and connected to each other.

7. Steam sieve according to one of the preceding claims, comprising a plurality of screen plate rings (30) which are lined up in the axial direction of the vapor sieve (10) and connected to each other, wherein at least a portion of the screen plate rings (30) obliquely formed to the axial direction sheet metal surfaces.

8. A method for producing a vapor sieve (10) according to any one of claims 1 to 7, wherein a plurality of screen plates (20) lined up in a zigzag ring and connected to each other.

9. A method for producing a vapor sieve (10) according to any one of claims 1 to 7, wherein a plurality of Siebblechringen (30) in the axial direction and strung together, wherein at least a portion of the Siebblechringe (30) has obliquely oriented to the axial direction of sheet metal surfaces ,

10. steam valve, comprising a vapor sieve (10) according to one of claims 1 to 7.

11. Use of a vapor sieve (10) according to one of claims 1 to 7 for a steam turbine plant.