FR3083832A1 - DISCHARGE VALVE FOR TAKING FLUID CIRCULATING IN A TURBOMACHINE VEIN - Google Patents

Abstract

The present invention relates to a relief valve comprising: • a casing (1) intended to separate a vein (2) from a discharge duct (3), • a door support (18) fixable to the casing (1), • a door (38) rotatably mounted on the support (18) between an open position and a closed position, • a first seal (48) arranged to be compressed by the door (38) against the support (18) in the closed position, to prevent gas flowing in the vein (2) from reaching the exhaust duct (3) passing between the door (38) and the door support (18), and • a second gasket seal (36) compressed between the support (18) and the casing (1) to prevent gas flowing in the stream (2) from passing between the casing (1) and the support (18) to reach the exhaust duct ( 3).

Description

FIELD OF THE INVENTION

The present invention relates to a relief valve for withdrawing fluid flowing in a turbomachine stream.

STATE OF THE ART

In a double-body turbomachine, the term “intermediate casing” usually designates a casing, the hub of which is arranged between a low pressure compressor casing and a high pressure compressor casing. Such an intermediate casing has an internal surface delimiting a primary gas flow stream.

It is known to equip such a turbomachine with a discharge valve ("Variable Bleed Valve" in English, abbreviated as VBV) to take gas from such a primary stream.

Illustrated in FIG. 1 is a portion of intermediate casing C delimiting a vein V, and a known discharge valve. The discharge valve comprises a door support S fixed to the housing C, and a door P movable relative to the door support S (and therefore relative to the housing C) between a closed position and an open position. In the open position, the door P authorizes gas flowing in the vein V to reach an evacuation duct E also defined by the casing C.

A seal J is arranged between the housing C and the door P. When the door P is in the closed position, the seal J is compressed by the housing C and the door P, so as to prevent gas flowing in the passage passing between the door support S and the casing C, and thus reaching the evacuation duct E. Furthermore, in the closed position, a surface 10 of the door P delimits the primary vein V.

A rod B of variable length is rotatably mounted on the door P to move the door P in the open position and in the closed position.

The surface of the door P should be correctly aligned with the internal surface of the casing C when the door P is in the closed position and when a gas flow circulates in the primary stream during the operation of the turbomachine, so that the door minimally disrupts this flow, as shown in Figure 1.

It is known practice to implement the following two adjustments during assembly of the relief valve.

A first adjustment to be made consists in aligning the upstream end of the surface 10 of the door with the internal surface 2 of the casing C (in the present text, the terms “upstream” and “downstream” refer to a direction of circulation of gas; in other words, the gas flows from upstream to downstream). To ensure this alignment, machining of the support 2 and / or of the casing C is implemented.

A second adjustment to be made consists in adjusting the length of the link rod B so that the downstream end of the surface of the door P is also aligned with the internal surface of the casing, when the door P is in the closed position and qu 'A gas flow circulates in the primary stream during the operation of the turbomachine. For this, the length of the rod B is adjusted to a first length, so that the door protrudes slightly in the primary stream relative to the internal surface of the casing C. The seal J is then compressed by the door P and through the casing C. A fluid is then injected into the vein under operating conditions of the turbomachine. The fluid circulating in the vein V pushes on the door P, which pivots slightly with respect to the casing C, and at the same time relaxes the seal J. We then check whether this push leads to a good alignment of the surface J of the door P and of the internal surface 2 of the casing C. If this is not the case, the connecting rod B is disconnected from the rest of the device, and its length is varied and the preceding steps are repeated.

However, this second adjustment can become difficult because of casting defects in the housing C.

A first foundry fault is the presence of excess material on the housing, causing excessive compression of the seal J between the housing and the door in its closed position. Due to this excessive compression, a fluid circulating in the primary vein V can only reach the secondary duct E once the door has pivoted by a certain angle starting from its closed position. During this pivoting, the seal J gradually relaxes without allowing the passage of gas towards the secondary duct E. In other words, the excessive compression of the seal causes a certain delay between the instant at which the door leaves the closed position and the instant when the door allows the fluid to be evacuated through the evacuation duct.

A second foundry defect is the absence of sufficient material in the casing at the joint J, resulting in insufficient compression of the seal J between the casing and the door in its closed position for the seal to properly perform its function. sealing.

These defects, the type of which is not foreseeable before the foundry of the casing, are also highly variable from one turbomachine to another.

STATEMENT OF THE INVENTION

An object of the invention is to better control the clearances which exist between the casing and the door of a discharge valve for a turbomachine.

To this end, a discharge valve is proposed for withdrawing the fluid flowing in a turbomachine stream, the discharge valve comprising:

• a casing intended to separate the vein from an evacuation duct, • a door support suitable for being fixed to the casing, • a door rotatably mounted on the door support between an open position in which the door authorizes gas circulating in the vein to reach the evacuation duct, and a closed position, • a first seal arranged to be compressed by the door against the door support in the closed position, so as to prevent gas flowing in the vein of reaching the exhaust duct passing between the door and the door support, and • a second seal arranged to be compressed between the door support and the casing, so as to prevent gas flowing in the vein between the casing and the door support to reach the exhaust duct.

The relief valve according to the present invention may include the following optional features, taken alone or in combination when technically possible.

Preferably, the first seal is attached to the door, and is spaced from the door support when the door is in the open position.

Preferably, the discharge valve comprises a rod of fixed or variable length rotatably mounted on the door to move the door in the open position and in the closed position.

Preferably the door support comprises a frame defining a through window that gas circulating in the vein can pass through to reach the exhaust duct when the door is in the open position, in which the first seal has an annular shape. coming to bear against the frame all around the through window, when the door is in the closed position.

Preferably, the door support comprises a frame defining a through window that gas flowing in the vein can pass through to reach the exhaust duct when the door is in the open position, in which the second seal has a shape ring in contact with the frame.

Preferably, the door comprises:

• a first part rotatably mounted on the door support, • a second part having a surface arranged to delimit the vein when the door is in the closed position, • positioning means configured to move the second part relative to the first part while the door is in the closed position.

Preferably, the door is pivotally mounted on the door support around a first axis, and the positioning means are configured to allow rotation of the second part relative to the first part around a second axis parallel to the first axis while the door is in the closed position.

Preferably, the door is pivotally mounted on the door support around a first axis, and the positioning means are configured to allow rotation of the second part relative to the first part around a third axis perpendicular to the first axis while the door is in the closed position.

Preferably, the positioning means are configured to allow translation of the second part relative to the first part so as to bring the surface of the second part closer and further away from the vein while the door is in the closed position.

Preferably, the positioning means comprise four tapped holes formed in the first part, four screws cooperating respectively with the four tapped holes, each screw being moreover connected to the second part by a ball joint.

It is also proposed a method for adjusting the above discharge valve, the method comprising machining the door support so as to reduce the compression of the first seal by the door support and by the door in the closed position.

DESCRIPTION OF THE FIGURES

Other characteristics, objects and advantages of the invention will emerge from the description which follows, which is purely illustrative and not limiting, and which should be read with reference to the appended drawings in which:

• Figure 1 is a longitudinal sectional view of a discharge valve known from the prior art;

• Figure 2 is a longitudinal sectional view of a relief valve according to a first embodiment of the invention, in an open state;

• Figure 3 is a perspective view from above of the discharge valve according to the first embodiment of the invention, in the open state;

• Figure 4 is a longitudinal sectional view of the discharge valve according to the first embodiment of the invention, in a closed state;

• Figure 5 is a perspective view from above of the discharge valve according to the first embodiment of the invention, in the closed state;

• Figure 6 is a longitudinal sectional view of a portion of the relief valve according to the first embodiment of the invention;

• Figure 7 is a perspective view from below of a part of the discharge valve according to the first embodiment of the invention;

• Figure 8 is a longitudinal sectional view of a relief valve according to a second embodiment of the invention;

• Figure 9 is a longitudinal sectional view of a portion of the relief valve according to the second embodiment of the invention;

• Figure 10 is a cross-sectional view of part of the relief valve according to the second embodiment of the invention.

In all of the figures, similar elements bear identical references.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 2 to 7, a turbomachine comprises a casing 1 separating a vein 2 in which a fluid is intended to flow when the turbomachine is in operation (typically a gas) and an exhaust duct 3.

The casing 1 is typically the intermediate casing mentioned in the introduction.

The casing 1 comprises in particular a first wall 4 having a first surface 6 delimiting the vein, and a second surface 8 opposite the first surface delimiting the evacuation duct 3.

An evacuation orifice 10 is formed in the first wall 4, this evacuation orifice 10 opening into the first surface 6 and into the second surface 8. This evacuation orifice therefore makes it possible to put the vein 2 and the exhaust pipe 3.

The first wall 4 typically has the shape of a ferrule extending around a central axis of the turbomachine. The first surface 6 is thus turned towards the central axis of the turbomachine.

The casing 1 also comprises a second wall 12 projecting from the second surface. The second wall includes a surface 14 which also delimits the evacuation conduit 3. Holes 16 are formed in the second wall 12 so as to open into the surface 14 which delimits the evacuation conduit 3.

The turbomachine comprises at least one discharge valve having the function of withdrawing part of a flow of fluid circulating in the vein, and in particular of the debris which would be transported by this flow, and of evacuating it by the evacuation duct. Thus, thanks to this valve, this debris is extracted from the vein via the evacuation duct before this debris damages equipment of the turbomachine located downstream of the vein.

The discharge valve comprises a door support 18 suitable for being fixed on the casing, more precisely on the second wall 12 of the casing.

The door support 18 comprises a fixing part 20 to the casing 1.

Holes 22 are formed in the fixing part 20 the holes are all parallel to the same axis (typically parallel to the central axis of the turbomachine). To fix the door support to the second wall, the fixing part 20 of the support 18 is positioned against the surface 14 of the casing 1 delimiting the evacuation duct 3, and each orifice 16 of the second wall is aligned with an orifice 22 door support correspondent. Fasteners 17 are passed through the different pairs of aligned holes. These fastening elements 17 typically each comprise a screw and a nut.

When the door support 18 is fixed to the casing, the support is located in the exhaust duct, out of the vein.

The door support 18 also comprises a connecting portion 24 to a movable door. The connecting part 24 typically comprises two coaxial orifices between which a space is provided. The axis of these coaxial orifices is perpendicular to the axes of the orifices 22 of the fixing part 20.

The door support 18 also comprises a support part 26. The support part 26 comprises a frame 28 defining a through window 30.

The frame 28 has a first surface 32 and a second surface 34 opposite the first surface 32; the through window 30 opens into the first surface 32 and into the second surface 34.

When the door support 18 is fixed to the casing 1, the first surface 32 faces the second surface 8 of the casing 1.

The fixing part 20, the connecting part 24 and the support part 26 are in one piece.

The discharge valve comprises a seal 36 arranged between the casing 1 and the door support 18 fixed to the casing 1. The seal 36 is compressed between the two facing surfaces 8 and 32. This seal 36 prevents a fluid flowing in the vein 2 from reaching the sealing duct 3 passing between the casing 1 and the door support 18 fixed to the casing 1.

The seal 36 extends around the discharge orifice 10. It is fixed to one of the two facing surfaces 8 and 32.

The discharge valve also comprises a door 38 suitable for being rotatably mounted on the door support 18.

More specifically, the door 38 comprises a first part 40, called the connecting part. The connecting part 40 is adapted to cooperate with the connecting part 20 of the door support 18 so as to form a pivot connection.

The connection portion 40 of the door 38 comprises two tabs provided with two coaxial holes intended to be aligned with the coaxial holes of the connection portion of the door support 18. A hinge is formed by the connection portion 20 of the door support 18, the connecting part 40 of the door 38, and by a connecting element passed through the orifices formed in these connecting parts 20 and 40.

By pivoting, via this hinge, the door 38 relative to the door support 18 fixed to the casing 1, the door 38 can be positioned in an open position (see Figures 2 and 3) and a closed position (see Figures 4 and 5 ).

In the open position, fluid and any debris circulating in the vein can pass through the discharge port 10, then the window 30, then enter the discharge conduit 3.

The connecting part 40 of the door 38 is also able to cooperate with a connecting rod 42 to form another pivot connection with an axis parallel to the axis of the pivot connection formed by the hinge connecting the door 38 to the door support 18.

The link is part of an actuation system intended to move the door 38 in its closed position and in its open position. The actuation system also includes a cylinder and a horn. This actuation system is known in itself.

The link 42 can be of variable length. In this case, the link comprises two parts screwed to each other; by screwing or unscrewing one of the two parts relative to the other part of the link, the length of the link varies. Alternatively, the link is of fixed length.

The door 38 also has a second part 44, called the obstruction part, which is capable of being engaged in the through window 30 formed in the door support 18. More precisely, when the door 38 passes from the closed position to the open position, the blocking part 44 leaves the window, and enters it when the door 38 passes from the open position to the closed position.

The obstruction portion 44 ends with a free surface 45 intended also to delimit the vein 2, when the door 38 is in the closed position.

The connecting part 40 comprises a flange 46 extending around the obstruction part 44. The flange 46 acts as a stop which limits the engagement stroke of the obstruction part 44 in the window 30.

The collar 46 is suitable for facing the frame 28 extending around the window, when the door 38 is in the closed position.

The valve comprises a second seal 48 arranged to be interposed between the door support 18 and the door 38, when the door 38 is in the closed position, and, in this closed position, to be compressed by the door support 18 and the door 38 so as to prevent fluid from the vein 2 from reaching the evacuation duct 3 passing between the door support 18 and the door 38 itself.

More specifically, the seal 48 is arranged to be compressed, when the door 38 is in the closed position, by the frame 28 and by the flange 46 facing each other.

The seal 48 is for example fixed on the flange 46, and extends all around the obstruction portion 44.

With reference to FIGS. 8 to 10, a discharge valve according to a second embodiment includes all of the above characteristics, except that the link of variable length 42 is replaced by a link 41 of fixed length. The discharge valve according to the second embodiment also includes the following characteristics.

The door 38 comprises positioning means 50 configured to move the second part 44 relative to the first part 40 while the door 38 is in the closed position.

The positioning means 50 are configured to allow rotation of the second part 44 relative to the first part 40 about a first axis parallel to the axis of the hinge while the door 38 is in the closed position (see figure 9).

Furthermore, the positioning means 50 are configured to allow rotation of the second part 44 relative to the first part 40 about a second axis perpendicular to the axis of the hinge while the door 38 is in the closed position. (see figure 10).

In addition, the positioning means 50 are configured to allow a translation of the second part relative to the first part along a third axis so as to bring the surface of the vein closer and further apart while the door 38 is in the closed position. The third axis is perpendicular to the first axis and the second axis.

The positioning means 50 comprise four tapped holes 52 formed in the first part 40, and four screws 54 cooperating respectively with the four tapped holes 52. Each screw is connected to the second part 44 by a ball joint 56. The four screws 54 are parallel to each other.

Preferably, the tapped holes are formed in inserts provided with a self-braking, for reasons of adaptation of material torque, and in addition to brake the screws and thus prevent the disruption of the system in operation.

By screwing out the four screws 54 simultaneously, the second part can be translated relative to the first part. By unscrewing or screwing only two neighboring screws among the four screws, the second part can be rotated relative to the second part, around the first axis or the second axis depending on the screws unscrewed, as illustrated by the arrows appearing on Figures 9 and 10.

A valve according to another embodiment includes all the characteristics of the valve according to the second embodiment, except that the rod 42 of variable length is used in place of the rod of fixed length 41.

In the proposed valve, the fact of inserting this seal between the door support 18 and the door 18, rather than between the door and the casing 1 makes it possible to better control the compression of this seal.

The accuracy of the system will be better because only two parts will be taken into account in the dispersion of the dead zone.

The seal support 18 can be machined with the position of the hinge axis connecting the door 38 to the door support as a reference. The dead zone will therefore be limited to the accumulation of two tolerance intervals: the linked tolerance interval during the machining of the door support 18 + the tolerance interval linked to the machining of the hinge pin. Foundry IT is no longer taken into account. In this text, a tolerance interval is a deviation that is authorized for the realization of the same dimension on several manufactured parts.

In addition, the seal 38 makes it possible to absorb larger dispersions linked to the foundry without having an impact on the delay discussed in the introduction. It is therefore no longer necessary to machine the housing 1 very precisely.

Furthermore, the positioning means make it possible to align the surface 45 relative to the surface 6 of the casing independently of the compression ratio of the seal 48.

The system also provides the advantage of not modifying the forces transmitted in the jack which controls the opening and closing of the VBV system: the compression of the seal remains the same regardless of the setting of the door sinking in the vein. On the door, the part 44 reconstituting the vein is no longer integral with the part 40 which carries the seal, the depression of the part 44 in the vein can be more or less significant without modifying the compression of the seal.

Claims (11)

1. Relief valve for withdrawing fluid flowing in a turbomachine stream (2), the relief valve comprising: • a housing (1) intended to separate the vein (2) from an evacuation duct (3), • a door support (18) suitable for being fixed to the housing (1), • a door (38) mounted rotatable on the door support (18) between an open position in which the door (38) allows gas flowing in the stream (2) to reach the exhaust duct (3), and a closed position, the valve of discharge being characterized in that it comprises: • a first seal (48) arranged to be compressed by the door (38) against the door support (18) in the closed position, so as to prevent gas flowing in the stream (2) from reaching the duct evacuation (3) passing between the door (38) and the door support (18), and • a second seal (36) arranged to be compressed between the door support (18) and the casing ( 1), so as to prevent gas flowing in the stream (2) from passing between the casing (1) and the door support (18) to reach the discharge duct (3). 2. Relief valve according to the preceding claim, wherein the first seal (48) is fixed to the door (38), and is spaced from the door support (18) when the door (38) is in position opened. 3. Relief valve according to one of the preceding claims, comprising a rod of fixed length (41) or variable (42) rotatably mounted on the door (38) to move the door (38) in the open position and in the closed position. 4. Relief valve according to one of the preceding claims, wherein the door support (18) comprises a frame (28) defining a through window (30) that gas flowing in the vein (2) can pass through to reach the exhaust duct (3) when the door is in the open position, and in which the first seal (48) has an annular shape abutting against the frame all around the through window (30), when the door is in closed position. 5. Relief valve according to one of the preceding claims, wherein the door support (18) comprises a frame (28) defining a through window (30) that gas flowing in the vein (2) can pass through to reach the exhaust duct (3) when the door is in the open position, and in which the second seal (36) has an annular shape in contact with the frame (28). 6. Relief valve according to one of the preceding claims, in which the door (38) comprises: • a first part (40) rotatably mounted on the door support (18), • a second part (44) having a surface (45) arranged to delimit the vein (2) when the door (38) is in the closed position , • positioning means (50) configured to move the second part (44) relative to the first part (40) while the door (38) is in the closed position. 7. relief valve according to claim 6, wherein the door (38) is pivotally mounted on the door support (18) about a first axis, and the positioning means (50) are configured to allow rotation of the second part (44) relative to the first part (40) about a second axis parallel to the first axis while the door (38) is in the closed position. 8. relief valve according to one of claims 6 to 7, wherein the door (38) is pivotally mounted on the door support (18) about a first axis, and the positioning means (50) are configured to allow rotation of the second part (44) relative to the first part (40) about a third axis perpendicular to the first axis while the door (38) is in the closed position. 9. Relief valve according to one of claims 6 to 8, wherein the positioning means (50) are configured to allow a translation of the second part (44) relative to the first part (40) so as to approximate and moving the surface (45) of the second part away from the vein (2) while the door (38) is in the closed position. 10. Relief valve according to one of claims 6 to 9, wherein the positioning means (50) comprise four tapped holes formed in the first part (40), four screws cooperating with the four tapped holes respectively, each screw being also connected to the second part (44) by a ball joint. 11. A method of adjusting the relief valve according to one of the preceding claims, the method comprising machining the door support (18) so as to reduce the compression of the first seal (48) by the door support (18) and through the door (38) in the closed position.