EP2161415B1 - Device and method for reducing the pressure on a dividing fugue between at least two neighbouring sections - Google Patents

Description

The present invention relates to a device, in particular a steam turbine, comprising at least a first boundary part and at least a second boundary part, wherein the boundary parts are fastened to each other to form a parting line and thereby enclose at least a portion of a first pressure chamber. Furthermore, the invention relates to a method for lowering the on a parting line, which is formed by the joining together of at least a first boundary part and at least a second boundary part of a device, in particular a steam turbine, acting pressure and to reduce the forces acting on the parting line fastening forces, wherein the Enclosing parts enclose at least a portion of a first pressure chamber.

In steam turbines, a flow channel is formed by various boundary parts or flow channel parts which are joined together. The flow channel formed is subjected to superheated steam under high pressure. Along the longitudinal axis of the flow channel pressure chambers are formed with different levels of internal pressures. Therefore, it is crucial that the connection of the various boundary parts is sufficiently dense, so that no leaks occur. This is particularly difficult because in a steam turbine steam or steam temperatures of more than 600 ° C can occur at a vapor pressure of about 250 bar.

At the connection between at least two boundary parts of the flow channel, a parting line is formed, with four boundary parts a so-called cross-sectional joint. A cross-sectional joint has both a horizontal and a vertical parting line. The formation of a cross-sectional joint is required if for manufacturing reasons or from Due to the choice of materials the first boundary parts and the second boundary parts of the flow channel separated, must be performed. The limitation parts generally have different materials with different thermal expansion coefficients and different constructions. Thus, a boundary part of a cast steel and the other boundary part may be formed as a welded construction or of a ductile iron. The flange connection on the joints, in particular the cross-part joints, must be designed for overpressure, for underpressure or usually for changing pressure conditions.

The execution of steam turbine housings with a cross-sectional joint has the advantage that the production of the blanks and the processing of the limiting parts can be made to smaller components. This opens up advantages in terms of both costs and procurement and processing capacity. However, cross-part joints have the disadvantage that, due to the limited space around the intersection of the part joints, there are only limited possibilities for secure screw connection. Thus, cross-part joints rather than other part joints, the risk of leakage and are performed for steam turbines only up to certain limited steam parameters.

It is known to equip Kreuzteilfugen with suction to absorb any occurring leakage quantities. Furthermore, it is known to weld a sealing seam on the inside of the vertical parting line. The problem here is a safe and sufficiently heat-transportable design of the weld, so that damage is avoided even in transient processes. Due to the high pressures and temperatures can lead to expansion of the corresponding boundary parts, so that it can lead to cracks and leaks at the sealing seam.

From the WO 99/00620 A1 is a steam turbine with a double-walled flange connection with an outer flange and provided with, between which a through-flow of a cooling medium space is formed.
The object of the invention is to provide a device and a method which make it possible to reduce the pressure and the forces on a parting line, in particular on a cross-sectional joint, between at least two mutually attached boundary parts of the device, in particular a steam turbine reduce if high pressures occur during operation of the device. In particular, a cross-sectional joint at boundary parts of a steam turbine is to be made accessible to a larger area of use.

This object is achieved by a device, in particular a steam turbine, having the features according to independent claim 1 and by a method having the features according to independent claim 19. Further features and details of the invention will become apparent from the dependent claims, the description and the drawings. In this case, features and details that are described in connection with the device according to the invention, in particular the steam turbine, of course, also in connection with the method according to the invention, and in each case vice versa, so that with respect to the disclosure of the individual aspects of the invention always reciprocal reference.

According to the first aspect of the invention, the object is achieved by a device, in particular a steam turbine, comprising at least a first boundary part and at least a second boundary part, wherein the boundary parts are fastened to each other to form a parting line and thereby enclose at least a portion of a first pressure chamber, in the a shielding element is provided on the sides facing the first pressure chamber sides of the limiting parts, which is arranged sealingly opposite the at least one first boundary part and the at least one second boundary part and thereby completely covers the parting line, so that between the boundary parts and the shielding element a cavity is formed, and that a conduit is guided into the cavity, which connects the cavity with a second pressure chamber, dissolved.

The core of the invention is that the region of the parting line which faces the first pressure chamber is subjected to a lower pressure than prevails in the flow channel when the device, in particular the steam turbine, is in operation. By lowering the pressure at the parting line, the forces acting on the attachment of the limiting parts, in particular the axial forces, can be reduced. The at least one first and the at least one second boundary part of the device are joined together. At the junction, a parting line, in particular a cross-sectional joint, is formed. The limitation parts are fastened to each other in particular by means of fastening screws. By shielding the parting line or the Kreuzteilfuge the pressure on the joint can be reduced and thus in particular the axial forces are reduced to the fastening screws of the flange connection between the boundary parts.

According to the invention, a shielding element is provided on the sides of the delimiting parts facing the first pressure chamber, which is sealingly arranged relative to the at least one first delimiting part and the at least one second delimiting part, thereby completely covering the parting line. By covering the parting line by the shielding a cavity is formed between the boundary parts and the shielding in the region of the parting line. In this cavity, a conduit is guided, which connects the cavity with a second, external pressure chamber. If the boundary parts form a flow channel of a steam turbine, then the area of the parting line or the cross-part joint is protected on the steam side by the shielding element, so that lower environmental parameters, ie a lower pressure and a moderately lower temperature, can be set in this shielded area. By connecting the cavity to the second pressure chamber, the pressure in the cavity can be adjusted to the pressure in the second pressure chamber.

The shielding effect is achieved in that a shielding element located inside the first pressure space formed by the delimiting parts completely covers the parting line or the cross-parting joint and seals on all sides of the joint, ie is arranged sealingly opposite at least one first and at least one second delimiting part. The pressure reduction takes place through the line which connects the cavity between the shielding, the boundary parts and the joint with a second pressure chamber located further downstream in the expansion. The second pressure chamber or the line to the second pressure chamber may, for example, be fixed to the inside of the at least one first and / or the at least one second boundary part or to a guide blade carrier of the device, in particular the steam turbine.

Such a device or such a steam turbine makes it possible to make the area of use of a joint joint, in particular a cross-part joint connection, accessible between the delimiting parts to a larger area of use.

In such a device or such a steam turbine, a reduction of the pressure in the cavity by about 15 to 20 bar compared to the pressure in the first pressure chamber of the steam turbine formed by the boundary parts can be achieved. Furthermore, a reduction of the effective internal pressure-related axial forces on the fastening screws by about 1/3 compared to conventional steam turbines is possible. The pressure reduction is accompanied by a moderate temperature reduction by throttling. This throttling comes about by the pressure reduction of any leakage mass flows from the interior into the cavity without performing technical work.

The shielding element can be designed in various ways. For example, this may have an angular or a curved profile.

The parting line may for example be formed next to a cross-parting joint as a Stoßteilfuge. Here, three boundary parts abut each other.

The at least one first and the at least one second boundary part preferably represent rotationally symmetrical or essentially rotationally symmetrical elements. Essentially rotationally symmetrical means that the elements can have cylindrical, conical or curved partial areas. Substantially rotationally symmetric elements may at certain points not rotationally symmetrical additions or sections, such as inflows, reinforcements or flanges exhibit. These rotationally symmetric or substantially rotationally symmetrical elements form the flow channel of the device or the steam turbine. It can also be provided more than two limiting parts, wherein the joints or the cross-sectional joints between the respective boundary parts are shielded according to the invention. The shielding element preferably also has a rotationally symmetrical or substantially rotationally symmetrical profile.

A device is preferred in which the line is led to the cavity through one of the limiting parts or through the shielding element. The conduit is preferably formed as a conduit and advantageously connects the cavity to a downstream flow direction, i. downstream in the expansion, lying second pressure chamber. In this case, the line, in particular the pipeline, partially or completely within and / or outside the boundary parts, that is, the first pressure chamber, are performed.

Furthermore, a device or a steam turbine is preferred in which the shielding element and the sealing of the shielding element are designed to be heat-movable. This allows different deformations of the limiting parts or the shield due to the partially prevailing high temperatures and the high pressures are compensated.

Particularly preferred is a device or a steam turbine, wherein the shielding attached to at least two circumferential receptacles on the boundary parts, in particular suspended, or that the shielding sealingly seated by at least two heat-resistant seals on the boundary parts or that the shielding at least one circumferential Receiving attached to at least one of the boundary parts, in particular suspended, and is sealingly seated by at least one heat-movable seal on the at least one other boundary part. It can thus be provided that on the inside of the first boundary parts a circumferential receptacle is provided, to which a first axial region, in particular a first free end of the shielding is sealingly secured, and that a heat-movable seal between the inside of the second boundary parts and a second axial region, in particular of the second free end, of the shielding element is provided. The attachment of the first axial region or of the first free end of the shielding element to the peripheral receptacle can be effected for example by means of screw connections or by insertion into a circumferential groove. In this case, the fixing of the shielding advantageously takes place axially and radially to the longitudinal axis of the flow channel at the peripheral receptacle. For better sealing, a sealing element may be provided in this attachment. If the shielding element is seated in a sealing manner with respect to the delimiting parts by means of at least two heat-resistant seals, the shielding element is preferably axially fixed by an axial fixation. This fixation can be done on a boundary part or a circumferential groove. In particular screw connections are particularly suitable.

Also preferred is a device in which at least one circumferential receptacle is formed by a stator part. The Stator part is sealingly fixed to at least one boundary part. Furthermore, the circumferential receptacle can be formed by an inwardly and / or axially projecting circumferential web. The shape or the configuration of the at least one circumferential receptacle can be varied.

Furthermore, it is preferred if the at least one heat-movable seal is sealingly seated on the at least one peripheral receptacle, in particular on the stator part or the surrounding web.

The heat-permeable sealing can be formed by a pressure and / or spring force-loadable piston ring, by a labyrinth or transparent seal or by at least one sealing plate. In particular, piston ring seals and labyrinth seals are very suitable for use under extreme operating conditions, ie at high pressures and temperatures. Labyrinth or see-through seals can have small games. It is also conceivable that a plurality of seals or sealing plates are provided for the heat-permeable sealing of an axial region, in particular a free end, of the shielding element.

In another preferred device, at least one of the boundary parts of the device has a groove for receiving the heat-movable seal. This creates a particularly good attachment and sealing of the shielding to the corresponding boundary parts. As a particularly sealing has proven to introduce a piston ring seal in the groove. The seal can be adjusted in the groove.

Furthermore, a device or a steam turbine is preferred in which the heat-movable seal is a split seal. A part of the split seal is after lifting the first boundary part in the vicinity of the parting line, in particular the Kreuzteilfuge, separable, so that thereafter, the remaining part of the shield can be dismantled. So can be provided as a split seal a piston ring seal in two parts and with two joints. Such a split seal can be arranged directly on the shielding element and / or on one of the delimiting parts and / or on at least one peripheral receptacle. A shock forms a separation point on the circumference of the piston ring. The joints have seals and optional entanglements.

Due to the possible expansion of individual components by the influence of heat, the line is preferably designed to be flexible and / or at least slidably mounted on the passage to the cavity. This can be avoided that the line breaks when it comes to thermal expansion of individual components. Despite the displaceability or flexibility of the line this is arranged sealed in the implementation of the cavity. If the line is designed as a pipe, this is preferably mounted displaceably, since the pipe is designed to be less flexible than a flexible line from the outset.

In a further preferred embodiment of the device, in particular the steam turbine, it is provided that the shielding element is at least divided into two, wherein the at least two parts of the shielding element are sealingly fastened to one another. It is particularly advantageous if the shielding element is divided axially. Thus, it can be provided that the segment of the shielding element, on which the heat-movable seal is arranged, is fastened to the second boundary part, and that the second segment is arranged on the first boundary part. In this embodiment, the segment with the heat-movable seal after disassembly of the first boundary part and the second segment of the shielding can be excavated together with a rotor of the steam turbine and then disassembled. In such an embodiment of the shielding a piston ring seal is particularly proven. The respective segments of the shielding element can by means of Screw and heat-resistant seals are sealingly fixed together.

The shielding element of the device preferably has at least one heating bore. Through a Anwärmbohrung a targeted mass flow of the hot steam flowing in the flow channel can be discharged into the cavity. Alternatively or additionally, heat-resistant seals may be used which have certain permeability. Such leaks having seals allow moderate leakage through the seals. Furthermore, a heating line which can be locked by means of a locking element can be led to the cavity. These measures serve to achieve an improved transient behavior of the shielded parting line or cross-sectional joint. They allow a temporary increase in the heat transfer coefficient of the shielded components, with the help of a temporary pressure increase between the shield, ie the shielding element, and the parting line or the vertical parting line of the cross-sectional joint. This is done for example by a targeted supply of a certain amount of the originally shielded superheated steam. The shielded hot steam can be temporarily supplied to the cavity via the lockable Anwärmleitung. The warming up line has at least one locking element. This locking element may for example be a slide, a regulator, a tap or a valve. But other types of locking elements are conceivable. If the shielding element heating holes or the seals have certain permeabilities, then a certain amount of superheated steam can be continuously supplied to the cavity. In order for the supplied hot steam can be held in the cavity, the line to the pressure chamber also has a locking element which can be closed if necessary, to increase the temperature and pressure in the cavity in the short term. The locking element of the conduit can also be designed as a slide, a regulator, a cock, a valve, etc.

In particular, by the locking element in the conduit to the second pressure chamber, the operating conditions within the cavity can be easily controlled. The locking element in the line allows a temporary damming of the pressure and also the temperature in the cavity and the line connection to the, usually downstream, second pressure chamber. After reaching a desired temperature level in the cavity and / or in the flange portions of the parting line, in particular the Kreuzteilfuge, or in the relevant for the unsteady operation sections of the delimiting the line to the second pressure chamber is fully opened again, so that for the stationary Operation again a lowered pressure in the cavity and thus adjusts the parting line. Through the opening of the line and the temperature level in the cavity or in the line is again adjustable.

Furthermore, a device is preferred in which at least one cooling steam line, which can be locked by means of a locking element, is guided to the hollow space via which cooling steam can be fed into the hollow space. That is, in addition to the above-mentioned improvements in terms of the pressure at the parting line or the cross-sectional joint and the axial force and the possible moderate temperature reduction by throttling can, if necessary, a further stationary temperature reduction at the parting line or the vertical parting of the cross-sectional joint can be achieved. This is necessary, for example, if admissible operating temperatures of limiting parts, of the shielding element or of screw materials are complied with or if a lowering of the component temperatures requires an increase in the strength characteristics. For this purpose, cooling steam is advantageously passed from a first, downstream with respect to the parting line, passage through the cooling steam line in the cavity between the shield and the parting line and returned through the line to a second, further downstream point. The pressure in the cavity may be due to the special piping design, in particular Pipe design, and any damming in the line, also referred to as discharge line, are set, in the limits of the pressure levels of the first and the second digit. This solution is technically sophisticated and requires a more massive design of the shield, ie the shielding. The additional benefit of the described measures for lowering the temperature can then be checked case by case. The Anwärmleitung, the cooling steam line and the discharge line have corresponding locking elements, by which a regulation of the pressure level is made possible. The locking elements may be, for example, a slide, a regulator, a tap or a valve. But other locking elements are conceivable. Furthermore, instead of or in addition to the locking elements, flow resistances, such as orifices, throttles, etc., can be used for the regulation of the pressure level within the lines, ie the line, the heating line and / or the cooling steam line.

In addition to the measures described above, can be arranged on the opposite sides of the first pressure chamber sides of the boundary parts on the parting line, in particular the Kreuzteilfuge, a suction device can be sucked through the leakage quantities. Furthermore, it can additionally be provided that a sealing seam is welded to the side of the parting line facing the first pressure chamber, in particular the vertical cross-part joint. It is important to ensure the safe and sufficiently heat-mobile design of the weld, so that damage is avoided even in transient processes.

According to the second aspect of the invention, the object is achieved by a method for lowering the pressure acting on a parting line, which is formed by the joining together of at least one first delimiting part and at least one second delimiting part of a device, in particular a steam turbine, and for reducing the pressure acting on the part Dividing joint acting fastening forces, wherein the boundary parts at least enclosing a part of a first pressure chamber, a shielding element being provided sealingly opposite the at least one first boundary part and the at least one second boundary part at the sides of the boundary parts facing the flow channel interior, thereby completely covering the parting line, so that between the boundary parts and the shielding a cavity is formed, and wherein from a second pressure chamber, a conduit is guided into the cavity, via which the pressure in the cavity is lowered to a lower level, dissolved.

The tight cover of the parting line on the inside of the boundary parts by a shielding creates a cavity. To the cavity, a conduit is guided, which is connected to a lying outside the cavity second pressure chamber. By connecting the cavity to the second pressure chamber, other operating conditions, in particular other temperatures and pressures, can be set in the cavity than in the first pressure chamber. In particular, by the pressure reduction, the burden on the parting line, in particular on the cross-part joint, reduced. It has been proven that a reduction of the pressure by 15 to 20 bar is possible. By this method of pressure reduction, the application of the parting line, in particular the cross-sectional joint, is significantly increased in steam turbines and other devices. That is, the application of a joint connection, in particular a cross-part joint connection is extended. The pressure reduction in the region of the parting line or cross-parting joint is made possible by a reliable heat-resistant shielding. By a suitably suitable design of the shielding a thrust balance for reducing the flange forces, ie, the forces acting on the fastening screws of the two boundary parts forces achieved. Due to the pressure reduction in the region of the parting line or cross-part joint, a reduction of the effective internal pressure-related axial forces by about 1/3 compared to the known devices in which no pressure reduction takes place, possible. By shielding the parting line or the cross-parting joint can be achieved a significant increase in the application of such joints.

Particularly preferred is a method in which the pressure acting on the parting line and the fastening forces acting on the parting line are lowered or reduced by a device, in particular a steam turbine, according to the first aspect of the invention.

Figur 1

einen Schnitt durch eine schematisch dargestellte erste Verbindungsmöglichkeit zweier Begrenzungselemente einer Dampfturbine;

Figur 2

einen Schnitt durch eine schematisch dargestellte zweite Verbindungsmöglichkeit zweier Begrenzungselemente einer Dampfturbine;

Figur 3

einen Schnitt durch eine schematisch dargestellte dritte Verbindungsmöglichkeit zweier Begrenzungselemente einer Dampfturbine;

Figur 4

einen Schnitt durch eine schematisch dargestellte vierte Verbindungsmöglichkeit zweier Begrenzungselemente einer Dampfturbine;

Figur 5

einen Schnitt durch eine schematisch dargestellte fünfte Verbindungsmöglichkeit zweier Begrenzungselemente einer Dampfturbine.

The invention will now be explained in more detail by means of embodiments with reference to the accompanying drawings. Show it:

FIG. 1

a section through a schematically illustrated first connection possibility of two boundary elements of a steam turbine;

FIG. 2

a section through a schematically illustrated second connection possibility of two boundary elements of a steam turbine;

FIG. 3

a section through a schematically illustrated third connection possibility of two boundary elements of a steam turbine;

FIG. 4

a section through a schematically illustrated fourth connection possibility of two boundary elements of a steam turbine;

FIG. 5

a section through a schematically illustrated fifth connection possibility of two boundary elements of a steam turbine.

The Fig. 1 to 5 show schematically different connection possibilities of two limiting elements 1, 2 of a steam turbine. On the side of the limiting elements 1, 2, which face the flow channel interior 4, is formed around the region of the parting line 3, which in particular as a cross-sectional joint is seconded, a shielding 5. In this case, the shielding element 5 completely covers the parting line 3, so that a sealed cavity 6 is formed between the two inner sides of the delimiting elements 1, 2, the parting line 3 and the shielding element 5. The shielding element 5 protects the parting line in front of the prevailing in the flow channel or in the first pressure chamber, which is at least partially formed by the two limiting elements 1, 2, prevailing conditions. In a flow channel or in a pressure chamber within a flow channel of a steam turbine in operation, temperatures of over 600 ° C and pressures of more than 250bar prevail. In order that the parting line 3 or the cross-sectional joint is not exposed to these high conditions, the shielding element 5 is sealingly attached to the boundary elements 1, 2 around the region of the parting line 3 or the cross-sectional joint. The boundary elements 1, 2 are formed as rotationally symmetric or substantially rotationally symmetrical elements or sub-elements. The shielding element 5 is sealingly attached to an axial region, in this case at a free end, on a circumferential receptacle 9 arranged on the first boundary part 1. The circumferential receptacle 9 may also be a stator of the steam turbine or a circumferential, inwardly projecting web. In this case, the shielding element 5 can be suspended from the circulated receptacle 9 at least slightly movably. A second axial region, in particular the second free end, of the shielding element 5 is arranged sealed on the inside of the second boundary part 2. To seal a heat-movable seal 10. This heat-resistant seal 10 may be, for example, a pressure and / or spring-loaded piston ring seal or labyrinth seal. The shielding element 5 has a passage in which a line 7 rests sealed. The conduit 7 connects the cavity 6 with a second, not shown, pressure chamber arranged outside the shielding element 5. Since a lower pressure level prevails in the second pressure chamber than in the flow channel interior, a pressure reduction in the cavity 6 can take place via the line 7. The line 7 is preferably at least partially flexibly formed and / or is slidably mounted in the passage to the cavity 6. The line 7 is preferably designed as a pipeline. In the passage to the cavity 6, the conduit 7 is arranged sealed by a sealing element 16. The conduit 7 is further downstream of a vane support 15, which is arranged on the circumferential receptacle 9 a, attached. The second pressure space may be provided downstream of the vane support, for example. The line 7 preferably has a locking element 13, in particular in the form of a valve. About this locking element 13, the conditions, in particular the pressure and the temperature within the cavity 6 can be controlled. In this embodiment of the steam turbine, the shielding element 5 has a Anwärmbohrung 12 through which a defined amount of superheated steam can be continuously supplied to the cavity 6. This serves to improve the transient behavior of the shielded parting line or cross-parting joint. By the continuous inflow of a certain amount of superheated steam and the achievable by closing the locking element 13 in the conduit 7 temporary pressure increase in the cavity 6, a temporary increase in the heat transfer coefficient of the cavity 6 surrounding components is possible. After reaching the desired pressure and temperature levels, the locking element 13 and thus the line 7 can be fully opened again, so that the pressure in the cavity 6 lowers again for stationary operation of the steam turbine. The two boundary parts 1, 2 have flange connections, are guided by the fastening screws 14. Alternatively or in addition to the Anwärmbohrung 12 may be provided that the heat-movable seal 10 has a certain permeability, can flow through the continuously a defined amount of superheated steam in the cavity 6. By shielding the parting line 3, the risk of leakage at the parting line 3 is reduced. Furthermore, a reduction in the force acting on the fastening screws 14 forces, in particular the axial forces achieved by the pressure reduction.

If two boundary parts 1, 2 are provided, these are connected to one another at a parting line 3. Three boundary parts form a Stoßteilfuge and four boundary parts form a Kreuzteilfuge.

Fig. 2 shows a further embodiment of the sealing of a parting line 3 and a Kreuzteilfuge between at least two boundary parts 1, 2 of a steam turbine. The difference to the embodiment according to the Fig. 1 lies in the heat-movable seal 10. In this embodiment, the heat-movable seal 10 is designed in two parts. In addition to the increased sealing function, the two-part seal 11 has advantages when mounting or dismounting the shielding element 5 on the at least one second boundary part 2. Particularly preferably, the split seal 11 is a piston ring seal in two parts and with two joints. The second pressure chamber is also in this and in the Fig. 3-5 not shown embodiments shown. The second pressure chamber is formed by the interior of the at least one first boundary part 1 and sealed lead carrier used. The second pressure chamber, in addition to the arrangement in the flow channel, can also be arranged outside the flow channel, ie outside the boundary parts 1, 2. The flange 8 of the shielding element 5 serves to close the parting line of the at least two-part shielding element 5.

The in the Fig. 3 shown variant of the sealing of a parting line 3 and a Kreuzteilfuge between at least two boundary parts 1, 2 of a steam turbine, has a different leadership of the line 7 between the cavity 6 and a second pressure chamber. The passage to the cavity 6 is not provided in the shielding member 5 but in the first restriction member 1. The line 7 is outside the flow channel, ie outside the first boundary part 1, out and is first performed in a downstream region in the flow channel interior 4 and connected there to the second pressure chamber, not shown.

The conduit 7 is sealingly secured in the passage to the cavity 6 in the at least one first boundary part 1 by sealing elements. The shielding element 5 is divided in this embodiment into two segments 5a, 5b. In this case, the shielding element 5 is divided axially. At the first Abschirmelementsegment 5a, the heat-movable seal 10, here in the form of a split seal 11, respectively. The second shielding element segment 5b is fixed to the circumferential receptacle 9 on the inside of the at least one first limiting part 1. The split seal 11 allows the first shield member segment 5a with the split seal 11, after disassembly of the first restriction member 1 and the second shield member segment 5b, to be excavated together with the rotor of the steam turbine provided in the flow passage interior 4 and disassembled accordingly. Particularly suitable as a split seal 11 is a piston ring seal. In order to prevent a possible thermal expansion of a component, in particular the first limiting part 1, the line is preferably mounted slidably in the passages or formed flexible at least one point. The Abschirmelementsegmente 5a, 5b each have a flange 8a, 8b, through which the at least two divided Abschirmelementsegmente 5a, 5b together and possibly on at least one of the boundary members 1, 2 and / or at least one circumferential groove 9, for example, a stator axially can be fixed.

Fig. 4 shows a further possible embodiment variant of the sealing of a parting line 3 and a Kreuzteilfuge between at least two boundary parts 1, 2 of a steam turbine. Instead of a Anwärmbohrung or a permeability having heat-movable seal a Anwärmleitung 17 is guided from the flow channel interior 4 in the cavity 6 in this embodiment. In this case, the Anwärmleitung 17 is not performed by the shielding 5, but by the at least one second boundary part 2 sealingly. By the Anwärmleitung 17 hot steam from the flow channel interior 4 and from the first pressure chamber into the cavity 6 to achieve a temporary pressure increase and an increase in the temperature in the cavity 6. To control the flow of hot steam, the Anwärmleitung 17, a locking element 18, in particular a valve, on. For pressure reduction, as in Fig. 3 , A conduit 7 is provided, which is guided partly outside the flow channel. With an opening of the locking element 18 of the Anwärmleitung 17 and a simultaneous closure of the locking element 13 of the line 7, the pressure and the temperature in the cavity 6 can be temporarily increased.

If a further stationary temperature reduction and pressure reduction at the parting line 3 or the Kreuzteilfuge to be achieved, for example, to comply with permissible operating temperatures of the limiting parts 1, 2 or 14 of fastening screws or to achieve an increase in the strength characteristics with a reduction in the component temperatures, cooling steam from a first downstream point through a further cooling steam line 19 into the cavity 6 between the shielding 5, the parting line 2 and the boundary parts 1, 2 are passed. Through the line 7, which ends at a second, more downstream point in the flow channel, in particular in a third pressure chamber, the supplied cooling steam can be removed again. The pressure in the cavity 6 can be adjusted by the specific design of the cooling steam line 19 and the line 7 and a damming in the line 7, in the limits of the pressure levels of the first and the second location. However, this solution is technically demanding and requires a more solid design of the shielding 5.

Claims (20)

1. Apparatus featuring at least one first delimiting part (1) and at least one second delimiting part (2), wherein the delimiting parts (1, 2) are able to be attached to each other by forming a joint (3) and in doing so enclose at least one part of a first pressure chamber, wherein on the sides facing towards the first pressure chamber of the delimiting parts (1, 2) a shielding element (5) is provided which is arranged to seal against the at least one first delimiting part (1) and the at least one second delimiting part (2) and in doing so fully covers the joint (3), so that a cavity (6) is formed between the delimiting parts (1, 2) and the shielding element (5), and that a line (7) is routed in the cavity (6) which connects the cavity (6) to a second pressure chamber,
   characterised in that
   the shielding element (5) features at least one preheating hole (12), that the seals allowing thermal expansion (10) feature leakages and/or that at least one preheating line (17) able to be locked by means of a locking element (18) is routed to the cavity (6) via which hot steam is able to be fed into the cavity (6), and that the line (7) between the second pressure chamber and the cavity (6) is able to be locked by a locking element (13).
2. Apparatus according to claim 1, characterised in that the joint (3) is a butt joint or a cross joint.
3. Apparatus according to claim 1 or 2, characterised in that the delimiting parts (1, 2) are elements embodied rotationally symmetrically or essentially rotationally symmetrically.
4. Apparatus according to one of claims 1 to 3, characterised in that the line (7) to the cavity (6) is routed through one of the delimiting parts (1, 2) or through the shielding element (5).
5. Apparatus according to one of the claims 1 to 4, characterised in that the shielding element (5) and the sealing of the shielding element (5) are embodied to allow thermal expansion.
6. Apparatus according to one of claims 1 to 5, characterised in that the shielding element (5) is attached to at least two circumferential supports (9) on the delimiting parts (1, 2), especially suspended, or that the shielding element (5) seats to form a seal through at least two seals (10) allowing thermal expansion on the delimiting parts (1, 2) or that the shielding element (5) is attached to at least one circumferential support (9) on at least one of the delimiting parts (1, 2), especially suspended, and seats to form a seal through at least one seal (10) allowing thermal expansion on the at least one other delimiting part (1, 2).
7. Apparatus according to claim 6, characterised in that the at least one circumferential support (9) is formed by a stator part.
8. Apparatus according to one of claims 6 to 7, characterised in that the least one seal (10) allowing thermal expansion seats so as to form a seal on the other least one circumferential support (9).
9. Apparatus according to one of claims 6 to 8, characterised in that the seal allowing thermal expansion (10) is formed by a compressible and/or spring-loaded piston ring, by a labyrinth or transparent seal or by at least one sealing plate.
10. Apparatus according to one of claims 6 to 9, characterised in that at least one of the delimiting parts (1, 2) features a groove to accept the seal allowing thermal expansion (10).
11. Apparatus according to one of claims 6 to 10, characterised in that the seal allowing thermal expansion (10) is a split seal (11).
12. Apparatus according to claim 11, characterised in that the split seal (11) is arranged on the shielding element (5) and/or on one of the delimiting parts (1, 2) and/or on at least one circumferential support (9).
13. Apparatus according to one of claims 1 to 12, characterised in that the line (7) is embodied flexibly and/or is supported to allow movement at least at the passage to the cavity (6).
14. Apparatus according to one of claims 1 to 13, characterised in that the shielding element (5) is at least divided into two parts, wherein the at least two parts (5a, 5b) of the shielding element (5) are able to be attached to each other to form a seal.
15. Apparatus according to one of claims 1 to 14, characterised in that, at least one cooling steam line (19) able to be locked by a locking element (20) is routed to the cavity (6), via which the cooling steam is able to be fed to the cavity (6).
16. Apparatus according to one of claims 1 to 15, characterised in that on the sides of the delimiting parts (1, 2) facing away from the first pressure chamber a suction device is arranged above the joint (3) in order to suck out leakage quantities.
17. Apparatus according to one of claims 1 to 16, characterised in that flow resistances are provided for controlling the pressure level within the line (7), the preheating line (17) and/or the cooling steam line (19).
18. Apparatus according to one of claims 1 to 17, characterised in that a sealing seam is welded to the side of the vertical joint (3) facing towards the first pressure chamber.
19. Method for decreasing the force acting on a joint (3), which is formed by the joining together of at least one first delimiting part (1) and at least one second delimiting part (2) of an apparatus and for reducing the attachment forces acting on the joint (3), wherein the delimiting parts (1, 2) enclose at least one part of a first pressure chamber, wherein a shielding element (5) is provided on the sides of the delimiting parts (1, 2) facing the first pressure chamber, which is arranged to form a seal in relation to the at least one first delimiting part (1) and the at least one second delimiting part (2) and in doing so completely covers the joint (3), so that a cavity (6) is formed between the delimiting parts (1, 2) and the shielding element (5), and that a line (7) is routed out of a second pressure chamber into the cavity (6) via which the pressure in the cavity (6) is reduced to a lower level
    characterised in that
    the shielding element (5) features at least one preheating hole (12), that the seals allowing thermal expansion (10) feature leakages and/or that at least one preheating line (17) able to be locked by means of a locking element (18) is routed to the cavity (6) via which hot steam is fed into the cavity (6), and that the line (7) between the second pressure chamber and the cavity (6) is locked by a locking element (13).
20. Method according to claim 19, characterised in that the pressure acting on the joint (3) and the attachment forces acting on the joint (3) are decreased by an apparatus, especially by a steam turbine, according to one of the previous claims 1 to 19.

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