Coolable wall element with impingement plate

Abstract

A coolable wall element for a gas turbine, having a base body with a first surface subjectable to a hot gas, second surface arranged opposite of the first surface, and first seat for housing edges of an impingement plate. The wall element has an impingement plate partly inserted into the first seat located at a distance and adjacent to the second surface. A coolable wall element with extended life time is provided with the impingement plate which is removably attached to the base body having a snap-in connection with a bendable retention tab extending from the rest of the impingement plate to a free end of the retention tab, wherein the base body has a second seat for the free end of said tab, the second seat blocks the moving of the impingement plate relative to the main body when the bendable retention tab is released.

Claims

1. A coolable wall element for a gas turbine, comprising: a base body comprising a first surface subjectable to a hot gas, a second surface which is arranged opposite of the first surface and a first seat for housing opposing edges of an impingement plate, the impingement plate partly inserted into the first seat, the impingement plate located at a distance and adjacent to the second surface being removably attached onto the base body, wherein the base body comprises at each edge of two opposing edges of the second surface a step each comprising a groove, wherein the grooves comprise opposing first openings facing to each other, said grooves each comprising a second opening through which said opposing edges of the impingement plate are insertable into the corresponding grooves, wherein the impingement plate is assembled into the grooves by aligning each of the two opposing edges of the impingement plate end-to-end with the respective second opening of each groove and translating the impingement plate parallel to the grooves so that the two opposing edges progressively enter the grooves until the impingement plate reaches a final assembly position, wherein the impingement plate comprises a bendable retention tab extending from the impingement plate to a free end of said bendable retention tab, wherein the bendable retention tab is flexed from an unbiased position as the impingement plate is translated, and wherein the base body comprises a second seat for the free end of said bendable retention tab, said second seat is configured to block movement of the impingement plate, relative to the base body when the bendable retention tab is released, wherein the bendable retention tab is released when the impingement plate reaches the final assembly position.

2. The wall element according to claim 1, wherein the second seat located on the second surface comprises a pin located adjacent to the free end of the bendable retention tab prohibiting movement of said bendable retention tab relative to the base body.

3. The wall element according to claim 1, wherein the second seat comprises a pedestal and said bendable retention tab comprises at the free end thereof a hole, wherein, when the bendable retention tab is released, the pedestal extends into said hole to block of the impingement plate relative to the base body.

4. The wall element according to claim 1, wherein the free end comprises a handle.

5. The wall element according to claim 1, wherein the bendable retention tab is partly separated from a rest of the impingement plate by a slot, said slot comprising an outer end located at one of the edges of the impingement plate and an inner end opposing the outer end, wherein said inner end comprises a key hole shape.

6. A turbine blade, turbine vane, ring segment or combustor shell element comprising: a wall subjectable to the hot gas, wherein said wall is configured according to the wall element according to claim 1.

7. A method for disassembling the impingement plate from the base body of the coolable wall element according to claim 1, the method comprising: first lifting elastically or plastically the bendable retention tab, and second moving the impingement plate out of the final assembly position while keeping the bendable retention tab bent at least temporarily.

8. A method for assembling an impingement plate onto a base body of a coolable wall, comprising the base body comprising a first surface subjectable to a hot gas, a second surface which is arranged opposite of the first surface and a first scat for housing opposing edges of the impingement plate and wherein the base body comprises at each edge of two opposing edges of the second surface a step each comprising a groove as the first scat of the impingement plate, the grooves comprise opposing first openings facing to each other, said grooves each comprising a second opening through which said opposing edges of the impingement plate are insertable into the corresponding grooves, wherein the base body comprises a second seat dedicated to receive a free end of a bendable retention tab of the impingement plate, said second seat is configured to block movement of said impingement plate relative to the base body when the bendable retention tab is released, and the impingement plate comprising the bendable retention tab extending from a rest of the impingement plate to the free end of said bendable retention tab, the method comprising: aligning each of the two opposing edges of impingement plate end-to-end with the respective groove and then translating the impingement plate in a direction parallel to the grooves so that the two opposing edges enter the grooves while temporarily lifting the bendable retention tab in a direction away from the second surface and into a biased position until the impingement plate approaches a final assembly position, and releasing or bending the bendable retention tab from the biased position, such that the free end of the bendable retention tab that has been released from the biased position sits in the second seat where the free end prohibits any further movement of the impingement plate relative to the base body.

9. A coolable wall element for a gas turbine, comprising: a base body comprising a first surface, a second surface opposite the first surface, a first side, a second side opposite the first side, a third side that connects the first side and the second side, and a fourth side opposite the third side, a retention feature, a first groove that extends along the first side and the first surface, and a second groove that extends along the second side and along the second surface and parallel to the first groove, wherein open faces of the grooves face each other; an impingement plate comprising a first edge, a second edge opposite the first edge, and a retention tab configured to flex from an unbiased position to a biased position; wherein installation of the impingement plate is effected by aligning the first edge end-to-end with the first groove, simultaneously aligning the second edge end-to-end with the second groove, flexing and holding the retention tab in the biased position, and then translating the impingement plate parallel to the grooves so that the first edge progressively enters the first groove and the second edge progressively enters the second groove until the impingement plate reaches a final assembly position, and wherein in the final assembly position the retention tab is released from the biased position to the unbiased position in which the retention tab engages the retention feature to prevent movement of the impingement plate relative to the base body.

10. The coolable wall element for a gas turbine of claim 9, wherein during the installation the retention tab is held away from the unbiased position by the base body until reaching the retention feature.

11. The coolable wall element for a gas turbine of claim 9, wherein the retention feature comprises a pin configured to block movement of the retention tab associated with translation of the impingement plate along the grooves when the retention tab is in the unbiased position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows in a perspective view a base body of a coolable wall element according to a first exemplary embodiment;

(2) FIG. 2 shows a perspective view of an impingement plate according to the invention; and

(3) FIG. 3 shows a coolable wall element with an attached impingement plate.

(4) FIG. 4 shows a detail view of the wall element with the attached impingement plate of FIG. 3.

DETAILED DESCRIPTION OF INVENTION

(5) In all figures identical features will have assigned with same reference numbers.

(6) The explanation of the invention is made with the aid of a ring segment of a gas turbine. Nevertheless the coolable wall element 10 according to the invention could be applied also on other devices of a gas turbine. Other devices could be also the platform of a turbine vane which is also cooled by impingement cooling, a turbine blade attachable to a rotor of a gas turbine or an impingement cooled wall element of a combustor shell.

(7) FIG. 3 displays in a perspective view a ring segment 50 as a coolable wall element 10 comprising a base body 12 and a removable attached impingement plate 32. Hooks 52 located in the cold side of the base body 12 are used to attach the ring segment to a turbine vane carrier (not shown).

(8) FIG. 1 displays only the base body 12, which comprises a first surface 14, which is subjectable to a hot gas, when the coolable wall element is assembled in a gas turbine. Opposite of the first surface 14 the base body 12 has a second surface 16 which is dedicated to be cooled by impingement cooling air jets generated by an impingement plate (not shown). The base body 12 comprises further on the second surface 16 steps 18 which are located at opposing edges 20 of the base body 12. Said steps 18 each extend along said edges 20. Advantageously, each of the four edges 20 of the base body 12, which usually has a rectangular shape, comprises a step 18 while surrounding the second surface 16 of the base body in a closed way. All steps 18 merge at their respective ends thus forming a tub 21 as a space to be covered by the impingement plate for impingement cooling.

(9) In this example two of these steps 18, have a height measured from the level of the second surface 16 which is larger than the height of the other edges 20. In two opposing steps 18 having the larger height grooves 22 are arranged therein providing a first seat for an impingement plate. These grooves 22 have opposing first openings facing to each other. Beside these first openings each groove 22 has on a face 25 of the base body 12 a second opening 24 through which opposing edges of the impingement plate could be slid in.

(10) In one corner 27 of the base body 12 on the side of the second surface 16 a second seat 28 is located for receiving a specific part of the impingement plate, which will be explained later. The seat 28 is partly bordered by a pin 30. The second seat 28 could also be located on other positions along the groove 22.

(11) FIG. 2 shows a perspective view onto an impingement 32 sheet according to the invention. The impingement sheet 32 has a corresponding shape with regard to the coolable wall element and according to this exemplary embodiment the shape of the impingement plate 32 is mainly rectangular and mainly flat. For creating retention tap 42 monolithically attached to the rest of the impingement plate 32 a slot 34 is machined therein. Said slot 34 has an outer end 36 located at one of the edges 38 of the impingement plate 32 and an inner end 40 opposing outer end 36 wherein said inner end has a keyhole shape for reducing notch stresses. The slot 34 has a very small gap width and extends parallel to a second edge 43 of the impingement plate 32 while creating a retention tab 42. This results in said retention tab 42 having a free end 44. The free end 44 has a curved design for creating a handle. The rest of the impingement plate 32 and may be also the retention tab 42 comprises a set of impingement holes 45 arranged in a regular or irregular pattern. Cooling air could flow through the impingement holes 45 while creating impingement jets for cooling the base body, when the coolable wall element or the ring segment is assembled in a respective gas turbine which is operated.

(12) The impingement plate 32 comprises further a cam 46 extending an edge 47, said edge 47 is opposite located of second edge 43.

(13) To create said coolable wall element 10 respectively a ring segment 50 the above mentioned impingement plate 32 and its corresponding, opposing edges 39 has to be inserted into the second openings 24 of grooves 22 of the base body 12. The second edge 43 of the impingement plate 32 comprising the retention tab 42 is inserted first into the second openings 24 of the grooves 22 while lifting elastically the retention tab 42 that much, that the retention tab 42 does not block any movement. In detail, the retention tab 42 is bent that much, that its free end 44 is arranged outside the groove 22. The impingement plate 32 with its lifted retention tab 42 is moved into its final position, where the impingement plate 32 fully covers the tub 21. When the cam 46 reaches a pin 31 located at the base body 12, the impingement plate 32 has reached its final assembly position. Latest then the retention tab 42 is to release. When releasing the retention tab 42 the free end 44 moves into the second seat 28. In other words: the retention tab 42 snaps back into its unbend position. In this position, the pin 30 blocks the motion of the retention tab 42 in the direction of the grooves 22, as the combination of pin 30 and pin 31 does also. In this position the impingement plate 32 is firmly fixed but also removable attached onto the base body while creating a coolable wall element 10. For disassembling, the actions have to be performed vice versa.

(14) Other blocking constructions for the snap lock are also possible. In example instead or in addition of pin 30 the second seat 28 could comprise a pedestal 60, which could extend into a hole 62 which could be located on the free end of the retention tab.

(15) FIG. 3 displays in a perspective view a ring segment 50 comprising the base body 12 and said removable attached impingement plate 32. Hooks 52 located in the cold side of the base body 12 are used to attach the ring segment to a turbine vane carrier (not shown).