Temporary liquid retention device at the end of a tube

Abstract

Temporary Liquid Retention Device at the End of a Tube. The invention relates to an assembly (2) comprising: a tube portion (9), terminated at one end (10) by an edge (11) which defines an opening (12), and a valve (15) with a sealing wall (16) movable between a closed position, in which the sealing wall rests against the edge and closes at least the lower part of the opening, and an open position in which the sealing wall is away from the edge and leaves the opening free. The sealing wall is preferably pivotable and fixed to the tube portion by at least one hinge (17), with a return means (21) which automatically returns it to the closed position. Figure to be published with the abbreviation: Figure 3

Description

Title of the invention: Device for the temporary retention of a liquid at the end of a tube. TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a device for the temporary retention of a liquid that may drip from the end of a tube.

[0002] More specifically, the invention relates to a valve-type shut-off device fixed to the end of a tube, which is open when fluid escapes from the tube under sufficient pressure and closed in the absence of pressure. In the closed position, this valve acts as a temporary reservoir for the liquid and prevents it from flowing back down the end of the tube.

[0003] Advantageously, it may be a device for retaining dripping oil, placed at the end of a tube through which oily air escapes.

[0004] More specifically, the invention may relate to a shut-off valve device, fixed to the end of an oiled air ejection tube opening into the secondary flow of a turbomachine, and intended to temporarily retain the oil flowing from this tube when the turbomachine is stopped.

[0005] The invention finds applications in the field of aircraft turbomachinery. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0006] In aircraft turbomachinery, it is common practice to depressurize the housings containing the bearings and other lubricated components to prevent oil from escaping. This is done by drawing some of the air from these housings and sending it to an oil separator, which separates the air from the oil it contains, in order to recover the oil and return it to the lubrication system. The air exiting the oil separator is typically discharged into the downstream section of the turbomachine's secondary flow, via an ejection tube opening upstream of the nozzle. This air then mixes with the airflow circulating in the secondary flow.

[0007] Since the oil separator's efficiency is not perfect, the air exiting the oil separator still contains a small amount of oil, which is sent via the ejection tube into the secondary flow of the turbomachine. This poses no problem as long as the turbomachine is running. Indeed, this oil is then carried away as suspended droplets by the high-speed airflow circulating in the secondary flow and conducted to the exhaust.

[0008] However, when the turbomachine stops, the airflow from the ejection tube and the secondary flow ceases. The oil still present on the walls of the ejection tube begins to flow down the walls and to the end of the tube, from where it trickles down in the form of liquid droplets. As there is no longer any gas flow in the flow secondary to carry them away, these droplets fall by gravity under the end of the ejection tube.

[0009] If a hot part of the turbomachine, such as the mixer or the exhaust cone, is located below this end, significant fumes are generated when oil droplets come into contact with this part, which remains hot long after the turbomachine has stopped. Although these fumes do not pose a safety risk, they are unacceptable because they are viewed very negatively by aircraft manufacturers and by aircraft crew members and passengers. They must therefore be avoided at all costs. Summary of the invention

[0010] The invention aims to solve this problem by proposing an oil retention device that can be used to temporarily store the oil flowing from the ejection tube when the turbomachine is stopped, thus preventing the formation of fumes.

[0011] To this end, a first aspect of the invention teaches a set comprising: • a section of tube, ending at one end with an edge that defines an opening, and • a movable shutter wall flap between a closed position, in which the shutter wall is against the edge and closes at least the lower part of the opening, and an open position in which the shutter wall is away from the edge and leaves the opening free.

[0012] This valve with a movable sealing wall thus forms a temporary retention device for the liquid flowing from the tube.

[0013] When the valve is in the open position, the gas flow can freely escape from the portion of the tube. The flow is therefore not impeded by the presence of the valve.

[0014] The valve is in the open position when the turbomachine is running. The oiled air can then escape from the tube section and mix with the airflow of the secondary flow. The oil droplets suspended in the oiled air are thus carried downstream by the airflow of the secondary flow.

[0015] When the turbomachine stops, the valve moves to the closed position. The sealing wall presses against the edge of the tube section and seals the lower part of the tube end. It thus forms a barrier that prevents the oil that has run off the walls from escaping. This oil accumulates against the sealing wall, which, together with the tube wall, forms a receptacle for storing the liquid. The valve advantageously retains and temporarily stores the liquid at the end of the tube section. The formation of fumaroles is thus prevented.

[0016] When the turbomachine is restarted, airflow is restored in the ejection tube and the secondary flow. The valve returns to the open position. The liquid oil The oil that it temporarily retained is then released. This oil is ejected out of the tube by the flow of oiled air exiting the ejection tube and blown downstream by the air flow of the secondary vein.

[0017] Advantageously, the valve's opening can be slightly delayed relative to the turbomachine's restart. This ensures that the flow rate in the discharge tube and the secondary channel is sufficient to satisfactorily remove all the liquid oil that was stored against the sealing wall when it is released upon opening the retention device.

[0018] Advantageously, in the closed position, the obturator wall preferably obturates between 1 / 3 and 2 / 3 of the opening and preferably about half of the opening.

[0019] Thus, even when the valve is closed, the sealing wall does not completely block the opening of the tube portion; only the lower part is closed. This ensures a minimum opening area even in the event of a valve failure or malfunction. The gas flow can therefore escape from the discharge tube, even if the valve has not opened when the turbomachine starts, thereby improving overall safety.

[0020] Advantageously, the assembly may further include a sealing gasket which is interposed between the sealing wall and the edge of the tube portion when the sealing wall is in the closed position. Such a gasket limits the risk of liquid leakage between the edge of the tube and the sealing wall.

[0021] Advantageously, this sealing gasket can be a curved gasket fixed along the edge of the tube section or around the periphery of the sealing wall. Preferably, it is a bead-type gasket, for example tubular or flat, which follows the edge of the tube, at least in its lower part, or the perimeter of the sealing wall. Such a gasket effectively limits the risk of leakage, while representing only a slight increase in weight.

[0022] Advantageously, the sealing wall can be pivoted about a pivot axis and fixed to the tube portion by at least one hinge. Such a configuration allows the valve to be implemented simply and reliably, without disturbing the flow escaping from the ejection tube in the open position and while minimizing disturbance of the airflow in the secondary vein.

[0023] Advantageously, to further reduce pressure losses in the secondary vein, the obturation wall preferably has a shape corresponding to that of the lower part of the end of the tube.

[0024] Advantageously, the assembly may further include a return mechanism that automatically returns the sealing wall to the closed position. The valve can thus be automatically closed as soon as the turbomachine stops, the wall a sealing device is then immediately in place to prevent problematic oil leaks.

[0025] Advantageously, this return means can be a torsion spring, centered on the pivot axis of the obturator wall, with a first arm bearing against the obturator wall and a second arm bearing against the portion of tube.

[0026] Such a return mechanism is very simple, reliable, inexpensive, lightweight, and compact. Furthermore, it allows for the automatic and very simple coupling of the valve's opening and closing with the flow of oiled air exiting the ejection tube, and thus with the operation or shutdown of the turbomachine.

[0027] Indeed, when the turbomachine is operating, the flow rate of oiled air circulating in the tube section is significant. The pressure of this air is sufficient to overcome the force of the spring exerted via its first arm against the sealing wall. The sealing wall is therefore automatically pushed into the open position by the flow of oiled air escaping from the tube section.

[0028] When the turbomachine stops, the flow of oiled air stops in the portion of the tube and the sealing wall is automatically returned to the closed position by the spring, thus preventing any oil runoff and any formation of fumes.

[0029] Advantageously, this spring can be calibrated so that the valve opens with a slight delay relative to the start-up of the turbomachine. This ensures that the airflow in the tube section and in the secondary flow is sufficient, at the moment the sealing wall pivots, to effectively blow away any released liquid.

[0030] Alternatively, the assembly may include an electric actuator that controls the movement of the sealing wall to the open or closed position.

[0031] Advantageously, the assembly may further include a cable which connects the sealing wall to the return means or to the electric actuator.

[0032] This cable transmits the force exerted by the electric actuator or the return means to the sealing wall. This makes it possible to move these devices away from the sealing wall and place them in a less obstructed or less obstructive location for airflow, for example, outside the secondary vein.

[0033] This cable can also allow the use of a tension spring as a means of return.

[0034] Advantageously, the tube portion can be a portion of an oil-lubricated air ejection tube from a turbomachine. The assembly then makes it possible to solve the fume problem mentioned above.

[0035] A second aspect of the invention relates to a turbomachine comprising an assembly as described above.

[0036] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0037] The figures are presented for illustrative purposes only and are in no way limiting of the invention.

[0038] [Fig. 1] is a schematic cross-sectional view of an example of an oiled air ejection tube of a turbomachine illustrating the technical problem to be solved.

[0039] [Fig.2] and [Fig.3] are schematic cross-sectional views of an example assembly according to the invention, the valve of which is respectively in the open position and in the closed position.

[0040] [Fig.4] and [Fig.5] are schematic perspective views, illustrating the end of the tube and the sealing wall respectively in closed position and open position.

[0041] [Fig.6] is a schematic perspective view, illustrating the end of the tube and the shutter wall in a partially open position, the movement of the shutter wall being controlled via a cable. DETAILED DESCRIPTION

[0042] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0043] In the present application, the terms "upstream" and "downstream" are defined with respect to the normal direction of gas flow (upstream to downstream) through a turbomachine.

[0044] The "turbomachine axis" is the longitudinal axis of the turbomachine corresponding to the axis of rotation of the turbomachine's rotor. A radial direction is a direction perpendicular to the turbomachine axis and intersecting this axis.

[0045] Unless otherwise specified, the adjectives "internal" and "external" are used in this application with reference to a radial direction such that the internal part of an element is, along a radial direction, closer to the axis of the turbomachine than the external part of the same element.

[0046] The terms "up", "down", "lower" and "upper" are defined in terms of the normal orientation of the turbomachine when installed in an aircraft flying horizontally and upright. This orientation corresponds to that shown in the figures.

[0047] Figure 1 schematically represents a portion of a turbomachine 1 in which an assembly 2 according to the invention could advantageously be installed. This is, for example, a turbofan engine.

[0048] The turbomachine portion 1 shown comprises an outer wall 3 ('outer fan duct' or OFD) and an inner wall 4 ('inner fan duct' or IFD) substantially cylindrical which extend inside each other.

[0049] They delimit between themselves an annular space of air flow constituting the secondary vein 5 (also called blower duct or "fan duct" in English), which extends from the blower to the exhaust nozzle 6 and in which part of the air drawn in by the blower circulates.

[0050] The other part of the air drawn in by the blower circulates in the primary vein (not shown) before also being sent into the exhaust nozzle 6.

[0051] A mixer 7, disposed at the inlet of the exhaust nozzle 6, is shaped to ensure the mixing around an exhaust cone of the gases exiting the primary vein with the airflow exiting the secondary vein 5.

[0052] As the gases exiting the primary stream have previously passed through a combustion chamber, they are very hot. Their contact gives the mixer 7 and the exhaust cone a temperature exceeding 250°C, which remains high long after the turbomachine 1 has stopped.

[0053] Conventionally, an air ejection tube 8 exiting the oil separator terminates in the downstream part of the secondary vein 5 with a portion of tube 9. The end 10 of this portion of tube 9 terminates with an edge 11 which delimits an opening 12 leading upstream of the nozzle 6.

[0054] Since the air coming out of this tube 8 still contains a small proportion of oil, it is called oiled air.

[0055] When the turbomachine 1 is in operation, oiled air exits at high speed from the portion of tube 9, then is rapidly drawn into the nozzle 6 by the airflow from the secondary vein 5. The oil droplets it contains then remain suspended in this flow and are carried downstream without running off the end 10 of the portion of tube 9.

[0056] When the turbomachine 1 stops, there is no longer any flow of oiled air in the tube 8, nor any air flow in the secondary channel 5. The layer of oil that coated the inside of the tube 8 descends by gravity and begins to flow down the portion of the tube 9 to its end 10. A liquid 13 composed of oil droplets 14 then begins to trickle through the opening 12 and falls by gravity onto the parts located below, namely, in the example shown, the mixer 7, which is still very hot. Fumes are then generated.

[0057] Examples of assembly 2 according to the invention, allowing this situation to be avoided, have been shown in figures 2 to 6.

[0058] In addition to the tube portion 9, this assembly 2 includes a valve 15 located at the end 10 of the tube portion 9.

[0059] This valve has a sealing wall 16, which is pivotable and fixed to the lower part of the end 10 of the portion of tube 9 by means of a hinge 17.

[0060] This sealing wall 16 is thus mobile between a closed position, shown in figures 3 and 4, in which it is supported against the edge 11 of the portion of tube 9 and seals the lower part of the opening 12, and an open position, shown in figures 2 and 5, in which, after pivoting downwards, it is moved away from the edge 11 and leaves the opening 12 free.

[0061] As can be seen in the enlargements of Figures 4 and 5, this sealing wall 16 preferably has a shape that corresponds substantially to the lower part of the end 10 of the tube portion 9, namely a semi-oval shape in the example shown. Thus, when the valve 15 is in the closed position, the sealing wall 16 hardly protrudes from the tube portion 9.

[0062] Furthermore, the height of the sealing wall 16 is preferably less than that of the opening 12, so as not to completely cover it when the sealing wall 16 is in the closed position and to leave the upper part of the opening 12 free for safety reasons. In the example shown, the sealing wall 16 thus covers slightly more than half of the opening 12.

[0063] In order to improve the sealing of the valve 15 when it is in the closed position, a sealing gasket 18 is preferably interposed between the sealing wall 16 and the edge 11 of the portion of tube 9. Such a gasket 18 advantageously prevents leaks, in particular at the hinge 17, when liquid 13 accumulates against the sealing wall 16 when the turbomachine 1 is stopped.

[0064] As shown, the sealing gasket 18 can be a curved gasket 19, fixed on the perimeter of the face 20 of the sealing wall 16 which is intended to rest against the edge 11. Alternatively, this curved gasket 19 can be fixed to the edge 11 of the portion of tube 9.

[0065] The assembly 2 may further include a return means 21, which automatically returns the sealing wall 16 to the closed position.

[0066] In the example of figures 2 and 3, it is a torsion spring 22, centered on the pivot axis P of the sealing wall 16. This torsion spring 22 has a first arm 23 bearing against the sealing wall 16 and a second arm 24 bearing against the portion of tube 9 at the lower part of its end 10. It thus exerts a force on the sealing wall 16 which automatically returns it to the closed position in the absence of an opposing force.

[0067] Any other equivalent return means may be used instead of the torsion spring 22. In particular, a tension spring may be used. In this case, the tension spring is, for example, positioned on top of the tube portion 9 and connected to the sealing wall 16 by a connecting cable 25.

[0068] Alternatively, the return means 21 can be replaced by an actuator, in particular an electric cylinder, whose movements are transmitted to the sealing wall by a connecting cable 25.

[0069] Such a connecting cable 25 is shown in [Fig. 6]. One or more pulleys 26 may also be provided to facilitate and secure the movements of the cable 25.

[0070] The automatic operation of assembly 2 is derived from the means described above.

[0071] As shown in [Fig. 2], when a flow of oiled air (symbolized by arrows 27) circulates in the portion of tube 9, it presses against the face 20 of the sealing wall 16 and opposes the restoring force of the torsion spring 22. If the pressure of the airflow is greater than this restoring force, it pivots the sealing wall 16 downwards. The valve 15 then ends up in the open position and the opening 12 is completely free.

[0072] The oiled airflow can freely pass through the entire section of the opening 12. It carries with it both the oil present in the oiled air in the form of suspended droplets, but also the oil in liquid form 13 potentially retained against the sealing wall 16 before the opening of the valve 15.

[0073] As shown in [Fig. 3], when the flow of oiled air ceases in the tube section 9, particularly when the turbomachine 1 stops, the force that was pressing against the face 20 of the sealing wall 16 and opposing the restoring force of the torsion spring 22 disappears. The restoring force of the spring 22 then automatically rotates the sealing wall 16 upwards, and the valve 15 moves into the closed position. The sealing wall 16 closes the lower part of the opening 12 and, together with the wall of the tube section 9, forms a temporary storage receptacle 28 in which the oil in liquid form 13 can accumulate without flowing out of the tube section 9.

Claims

Demands

1. Assembly (2) comprising a portion of tube (9) terminated at one end (10) by an edge (11) which delimits an opening (12), assembly (2) characterized in that it further comprises a valve (15) with a sealing wall (16) movable between a closed position, in which the sealing wall (16) is in contact with the edge (11) and closes at least the lower part of the opening (12), and an open position in which the sealing wall (16) is away from the edge (11) and leaves the opening (12) free.

2. Assembly (2) according to claim 1 characterized in that in the closed position, the sealing wall (16) closes between 1 / 3 and 2 / 3 of the opening (12) and preferably about half of the opening (12).

3. Assembly (2) according to any one of the preceding claims characterized in that it further comprises a sealing gasket (18) which is interposed between the sealing wall (16) and the edge (11) of the portion of tube when the sealing wall (16) is in the closed position.

4. Assembly (2) according to claim 3 characterized in that the sealing gasket (18) is a curvilinear gasket (19) fixed along the edge (11) of the portion of tube (9) or at the periphery of the sealing wall (16).

5. Assembly (2) according to any one of the preceding claims characterized in that the sealing wall (16) is pivotable about a pivot axis (P) and fixed to the portion of tube (9) by at least one hinge (17).

6. Assembly (2) according to any one of the preceding claims characterized in that it further comprises a return means (21) which automatically returns the sealing wall (16) to the closed position.

7. Assembly (2) according to claims 5 and 6 characterized in that the return means (21) is a torsion spring (22) centered on the pivot axis (P) of the sealing wall (16), with a first arm (23) bearing against the sealing wall (16) and a second arm (24) bearing against the portion of tube (9).

8. Assembly (2) according to 6 characterized in that it further comprises a cable (25) which connects the sealing wall (16) to the means of return (21).

9. Assembly (2) according to any one of the preceding claims characterized in that the portion of tube (9) is a portion of an oiled air ejection tube of a turbomachine (1).

10. Turbomachine (1) comprising an assembly (2) according to any one of the preceding claims.

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