EP1965035B1 - Minimisation of the axial gap for adjustable guide vanes and for a contour ring for hot gas expanders - Google Patents

Abstract

The flow machine (1) has a rotating blade with rotor, a housing and a fixed flow contour e.g. inlet guiding apparatus (4), contour ring (6). The flow contour is twisted by a flexible element against a housing, so that the clamping forces are acted between the rotating blade and the flow contour from the flexible element in decreasing direction of cleave.

Description

• einen Laufschaufeln umfassenden Rotor aufweist,
• einen Eintrittsleitapparat aufweist, mit einen Stellring, mit zumindest einen Abstandhalter und mit Leitschaufeln, wobei ein Verdrehen des Stellrings ein Verdrehen der Leitschaufeln bewirkt,
• ein Gehäuse und einen Konturring aufweist, welcher Strömungskanäle im Bereich der Laufschaufeln einseitig begrenzt.

The invention relates to a turbomachine, in particular Heißgasexpander, which flow machine,

• Having a rotor blades,
• an inlet guide, with a collar, with at least one spacer and vanes, wherein a rotation of the collar causes a twisting of the vanes,
• a housing and a contoured ring which limits flow channels in the region of the blades on one side.

From the EP 1 249 577 A1 , of the EP 1 643 172 A1 , of the WO 01/09488 A1 , of the US 5,203,673 A In each case, mechanisms for active gap control of a turbomachine are known in which a drive displaces a housing part bearing at least one seal in such a way that radial gaps can be reduced or increased to form blades of a conically widening flow channel of a turbomachine, so that a gap minimum can be achieved in the interest of improving the efficiency is. Similar to the active gap control discloses the DE 2 165 528 a manual adjustability of the gap, wherein instead of a linear drive for moving the housing part, an adjustable screw connection is provided.

The EP 1 620 633 B1 discloses a radial expansion hot gas expander having an adjustable inlet guide vane in which the adjustable vanes are held in a defined position by a resilient member in which the resilient member biases the vanes in the direction of the respective axis of rotation. From the JP 02 22 36 06 It is also known to reduce secondary flows of a centrifugal compressor in the region of exit from the impeller, in which an actuator displaces the wall opposite the impeller in the direction of minimizing the gap.

Turbomachines, such as gear machines, in particular hot gas expander of the type mentioned are characterized by a multi-shaft arrangement with different rotational speeds to a central drive wheel. This provides a compact unit for multi-stage compaction / expansion for a variety of media, preferably gaseous media.

Such gear machines expand the medium having an inlet temperature of up to 300 ° C or, in a preferred embodiment, an inlet temperature of over 300 ° C can have. At a media inlet temperature of more than 300 ° C one speaks of so-called hot gas expanders.

These Heißgasexpander have at least one inlet housing, in which the spiral insert is arranged. The spiral insert carries an adjustable Eintrittsleitapparat having a collar, vanes and bolts, wherein the bolts serve as a rotation axis for adjusting the vanes.

The guide vanes are therefore rotatably struck on the bolt, wherein the guide vanes are simultaneously connected via a driver with the adjusting ring. If now the adjusting ring is rotated in a desired angular amount, the drivers cause a forced adjustment of the guide vanes about the bolt, so that the adjustment of the guide vanes influencing the direction and / or the speed of the medium flow to the blade or the impeller is effected.

The spiral insert thus has two functions. On the one hand, the spiral insert carries the adjusting mechanism (adjusting ring, etc.), with the spiral insert on the other also carries the contour ring.

The spiral insert with the associated inlet guide and the contour ring is pre-assembled outside of the inlet housing and used as a unit in this.

Due to the high thermal load, in particular with hot gas expanders, however, it is observed that the different component components expand or expand differently due to the thermal effect. Due to the usually rigid connection of the spiral insert with the associated components to the inlet housing, the unit to be used must therefore be performed during assembly with a relatively large radial clearance to the inlet housing or the impeller to clamps by different thermal expansions to avoid and to ensure axial freedom of movement.

As a result, but the contouring gap between the contour ring surface and the corresponding blade edge of the impeller is sized so large that the efficiency of the hot gas expander is significantly reduced by extremely high gap losses. Efficiency losses can also occur if the gaps between the guide vanes or the bolt (as the axis of rotation of the respective vane) and the associated channel inner wall are too large.

The invention is therefore based on the object to improve a turbomachine of the type mentioned, in particular a hot gas expander, by simple means to the effect that the gap losses are reduced, so that the efficiency can be significantly increased.

According to the invention the object is achieved in that the Eintrittsleitapparat and the contour ring are clamped together by means of at least one elastic element against the housing, so that the clamping forces from the elastic element in the direction of a reduction of gaps between the blades and the contour ring act.

Due to the elastic element according to the invention, which is referred to below as the clamping system, the flow contour or an associated spiral insert is movable to the inlet housing or to the housing, wherein the spiral insert is preferably seen in the axial direction movable.

Favorable in the context of the invention, when the clamping system has central receiving bolts, the diffuser side is assigned in each case a plant, wherein the respective receiving bolt is assigned a respective stop element on the spiral insert side, each of which is fixed frictionally to the respective locating bolt, wherein the respective locating bolt an energy storage and an active element is assigned. The active element is preferably arranged on the spiral insert side, the force accumulator being arranged between the active element and the contact base.

In a preferred embodiment of the energy storage is designed as a plate spring package or cup spring ring, which is arranged around the receiving bolt around.

Appropriately, the active element is provided with pot-like holes. In the hole bottom of the pot-like bores in each case a corresponding to the receiving pin through hole is introduced, so that the active element is slidably mounted along a longitudinal axis of the receiving pin. The stop element acts as a kind of movement limiter of the active element in the direction of the spiral insert. The active element is in the tensioned state preferably on the spiral insert.

The inlet guide apparatus has a spacer which is accommodated in the spiral insert on the foot side and is oriented on the head side to a channel inner wall, wherein the clamping system presses the spacer with its head side against the channel inner wall, which at least partially has a sliding element. The Eintrittsleitapparat also has a collar and vanes. The vanes are connected via drivers with the adjusting ring, and rotatably associated with the spacer. The spacer can thus also be referred to as a guide blade bolt and serves as a rotation axis of the guide vanes. When adjusting the adjusting ring in a desired angle amount, the vanes over the drivers are forcibly taken with them and turn around the respective blade axis or around the respective spacer. Appropriately, each spacer is associated with a sliding element, so that the respective sliding elements are arranged at the location assigned to the spacer in the channel inner wall. Of course, but also a single, continuous sliding element may be provided.

In a preferred embodiment, the sliding element is used as a sliding plate in the channel inner wall sufficiently secure. The sliding element can also be designed as a sliding coating. The sliding element in its embodiment as a sliding plate is formed of a suitable material, which is preferably made of a temperature and corrosion-resistant base material, and is coated or treated accordingly. For example, the sliding elements or sliding plates made of steel or Inconel and be coated with a special layer (eg Tribaloy). The coating is preferably chosen such that a sliding friction coefficient is reduced, and at the same time a high wear resistance is present. The coating also prevents seizing and is corrosion resistant. Alternatively, a treatment by Kolsterizing ^® (corrosion-resistant surface hardening) is possible. Of course, the slider may be applied in the embodiment as a sliding coating according to the coating directly on the associated region of the channel inner wall.

The spiral insert is pre-assembled with the inlet guide outside the inlet housing and inserted into this as a unit. The spiral insert is pressed with suitable tools axially over the spacers (Leitschaufelbolzen) against the sliding plates in the inlet housing rear wall (channel inner wall), whereby then the contour ring is installed and adjusted (axial gap). Subsequently, the clamping system is used at the intended location. Subsequently, the diffuser is connected to the inlet housing, or screwed, the diffuser with its abutment flange abuts the plant foot. By connecting or screwing the diffuser with the inlet housing, the clamping system is biased. Of course, the clamping system, in particular the cup spring assembly is designed prior to assembly with respect to the required spring tension even under operating conditions. Of course, the respective components (spiral insert, inlet guide, contour ring) are designed accordingly.

The clamping system presses the spacers with their head side against the corresponding sliding element or the preferred sliding plate. With differences in the thermal expansion of the individual components, sliding in the radial direction is advantageously achieved, since the spacers are supported on the sliding elements. Next is achieved by the thermal expansion advantageous axial compression of the disc springs. By pressing or clamping the spacer against the channel inner wall also eliminates gap material, which can be caused by deformation of the inlet housing. As axial thermal expansion can thus advantageously only the blade height of the vanes find consideration for gap design. Due to the small gap at Eintrittsleitgitter (vanes), the efficiency is increased.

The Heißgasexpander also has the impeller, which is spaced with its blade edges to the contour ring, so that a contouring gap is formed. By means of the advantageous clamping system, this contouring gap can be advantageously minimized, since the temperature expansion acts directly on the spacer, which is supported on the channel inner wall or the respective sliding element, and pushes the contour ring away from the impeller in a thermally induced expansion, so that the thermal Expansion of the blades and the contour ring quasi picks up.

Overall, it is thus advantageously achieved that gap losses are reduced, as a result of which the efficiency of the turbomachine or of the geared machine or of the exemplary one Hot gas expander is increased. The gap dimensions can be performed minimally from the outset, whereby it is achieved by means of the clamping system that the thermal expansion is virtually compensated.

Advantageously, it is further achieved by means of the clamping system that excessive component stresses are prevented by thermal expansion, since the spiral insert in the radial and axial direction is free from the inlet housing.

Fig. 1

einen Querschnitt durch einen beispielhaft dargestellten Heißgasexpander, und

Fig. 2

ein elastisches Element (Spannsystem) als Einzelheit.

Further advantageous embodiments of the invention are disclosed in the subclaims and the following description of the figures. Show it:

Fig. 1

a cross section through a exemplified hot gas expander, and

Fig. 2

an elastic element (clamping system) as a detail.

In the different figures, the same are always provided with the same reference numerals, which is why these are usually described only once.

FIG. 1 shows a turbomachine or a gear machine, which is designed in the illustrated embodiment as a hot gas expander 1 with an inlet temperature of a preferably gaseous medium of up to 510 ° C. The hot gas expander 1 has at least one inlet housing 2, in which a spiral insert 3 is arranged. The spiral insert 3 is assigned an inlet guide 4 and a contour ring 6, so that a flow contour is formed. The inlet housing 2 is further associated with a diffuser 7.

The inlet guide 4 has an adjusting ring 8, at least one spacer 9 and vanes 11.

The guide vanes 11 are connected via drivers with the adjusting ring 8, so that a rotation of the adjusting ring 8 causes a corresponding adjustment of the guide vanes 11 which are rotatably mounted on the spacers 9. The spacers 9 thus serve as the axis of rotation of the guide vanes 11.

The spiral insert 3 is associated with an elastic element or a clamping system 12. The clamping system 12 rests on the one hand on the spiral insert 3 and on the other hand on the diffuser 7 or on its abutment flange 13 to the inlet housing 2.

In the in FIG. 2 In the illustrated embodiment, the clamping system 12 has a central receiving bolt 14, to which a plant foot 16 is associated with the diffuser side. The plant foot 16 rests with its contact surface 17 against a corresponding abutment surface 18 of the diffuser 7 or its abutment flange 13. On the spiral side, the receiving bolt 14 is assigned a stop element 19, which is fixed in a form-fitting manner to the receiving bolt 14 via a screw connection. Of course, the stop member 19 may also be connected to the locating bolts 14 in any other suitable manner of connection. For example, the stop element 19 could be welded to the locating bolt.

Next, the receiving bolt 14, an active element 21 and a force accumulator 22 are assigned.
The active element 21 is preferably arranged on the spiral side, and provided with pot-like holes, of which in FIG. 2 due to the selected display range, only one is recognizable, so that the active element 21 seen in the selected section is U-shaped with a base web 23 (bottom hole) and two U-legs 24 is executed. In the base web 23 (bottom of the hole), a through hole 26 corresponding to the receiving bolt 14 is inserted, so that the active element 21 is movable along a longitudinal axis (double arrow 27) of the receiving bolt 14. The U-legs 24 are oriented with their free ends 28 in the direction of the spiral insert 3, so that the active element 21 rests against the spiral insert 3 in the clamped state of the clamping system 8.
The energy accumulator 22 is disposed between the active element 21 and the Anlagefuß 16, and preferably designed as a plate spring package or as a cup spring ring.

The spacer 9 is accommodated on the foot side in the spiral insert 3, and is oriented on the head side to a channel inner wall 29 (FIG. FIG. 1 ). The clamping system 12 presses the spacer 9 with its head side 31 against the channel inner wall 29, on which at least on the contact surface of the spacer 9 sliding elements 32 are provided.

The sliding elements 32 are executed in the illustrated embodiment as sliding plates, which are formed from a suitable material and preferably coated or processed accordingly. The sliding elements 32 are sufficiently secure in the channel inner wall 29 introduced.

The hot gas expander 1 is of course associated with an impeller 33, the blades are spaced with their edges 34 in the direction of the contour ring 6, so that a contouring gap 36 is formed.

The spiral insert 3 is preassembled with the inlet guide 4 outside the inlet housing 2 to form a unit us as a unit in the inlet housing 2. The spiral insert 3 is pressed with suitable tools axially over the spacers 9 (Leitschaufelbolzen) against the sliding plates in the inlet housing rear wall (channel inner wall 11), so then the contoured ring 6 is installed and adjusted (axial gap). Subsequently, the clamping system 12 is used. By means of the diffuser 7, the inlet housing 2 is closed by the abutment flange 13 is screwed to the inlet housing 2. As a result, the clamping system 12 is tensioned, whereby the gap between the guide vanes 11 and the channel inner wall 29 as well as the contouring gap 36 can be set to a minimum amount. The spiral insert 3 is free of the inlet housing 2 in the radial and in the axial direction.

Under operating conditions, in particular at an inlet temperature of a medium, preferably a gaseous medium above 300 ° C, for example of 510 ° C, the individual components can expand due to the thermal effect. By the clamping system 12, the spacers 9 are pressed via the spiral insert 3 against the channel inner wall 29 and against the sliding elements 32, so that here a sliding in the radial direction is effected. As axial thermal expansion, only the blade height of the guide vanes must advantageously be taken into account. By pressing the spacer 9 to the channel inner wall 29 accounts for additional gap dimensions, which could be caused by a (thermal) deformation of the inlet housing 2. At the same time, the contoured ring 6 is pressed away from the blades of the impeller 33 by the pressing of the spacer 9 against the sliding elements 32.

Overall, it is achieved by means of the advantageous clamping system 12 that excessive component stresses can be prevented by thermal expansions, since the spiral insert 3, which is also carrier of the inlet guide 4, at least in the axial direction is free from the inlet housing 2. Thus, gaps between the guide vanes 11 and the channel inner wall 29 but also the contour ring gap 36 can be made minimal, since only the blade axis so the spacer 9 must be taken into account for the thermal expansion. Due to the thermal expansions, there is a radial sliding over the sliding elements 32 and an axial compression of the force accumulator 22 or of the cup spring package.

In the in FIG. 1 illustrated embodiment, the spiral insert 3 is also associated with an adjustment system 37 for radial adjustability and a suitable sealing system 38 that seals the contour ring 6 to the diffuser 7.

Claims (8)

1. Flow machine (1),
   in particular a hot gas expander,
   which flow machine has

   - a rotor (33) comprising rotor blades,

   - an intake guiding device (4) having a set collar (8), at least one spacer (9) and guide vanes (11), wherein rotating the set collar rotates the guide vanes,

   - a housing (2);

   characterized in that the flow machine has a contour ring (6), which delimits on one side flow channels in the region of the rotor blades,
   wherein the intake guiding device (4) and the contour ring are together braced against the housing (2) by means of at least one elastic element (12),
   such that the bracing forces from the elastic element (12) act so as to reduce gaps between the rotor blades and the contour ring.
2. Flow machine according to Claim 1,
   characterized in that
   the spacer (9) is arranged between the contour ring and the housing (2).
3. Flow machine according to Claim 2,
   characterized in that
   the spacer (9) forms the rotation spindle of guide vanes.
4. Flow machine according to one of the preceding claims,
   characterized in that
   the elastic element (12) is in abutment against a spiral insert (3) on one side and against a diffuser (7) on the other side.
5. Flow machine according to one of the preceding claims,
   characterized in that
   the elastic element (12) has central locating pins (14) to which in each case a contact foot (16) is assigned on the diffuser side,
   wherein in each case a stop element (19) is assigned to the respective locating pin (14) on the spiral insert side, and wherein an operating element (21) and an energy storing device (22) are assigned to the respective locating pin (14).
6. Flow machine according to Claim 5,
   characterized in that
   a through bore (26) corresponding to the locating pin (14) is incorporated in the operating element (21).
7. Flow machine according to one of the preceding claims,
   characterized in that
   the heads of the spacers (9) are pressed against a channel internal wall (29) by means of the elastic element (12), wherein at least one sliding element (32) is assigned at least to a region of this wall.
8. Flow machine according to Claim 7,
   characterized in that
   the sliding element (32) is formed as a slide plate, which preferably has a slide coating.

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