ROTATING MACHINE COMPRISING A SEAL RING DAMPING SYSTEM

Abstract

A rotating machine having a rotor mounted to rotate in a casing and bearing at least a plurality of impellers is provided. The machine may include at least one seal ring disposed radially between the rotor and the casing and mounted to move radially in a seal support of the casing, and wherein it includes a damping system for the seal ring disposed radially between the seal ring and the seal support. The damping system is configured to damp the seal.

Claims

1. Rotating machine comprising a rotor mounted to rotate in a casing and bearing at least a plurality of impellers, the machine comprising at least one seal ring disposed radially between the rotor and the casing and mounted to move radially in a seal support of the casing, wherein it comprises a damping system for the seal ring disposed radially between the seal ring and the seal support, the damping system being configured to damp the seal.

2. Machine according to claim 1, in which the seal ring comprises a fixing part in the seal support secured to the casing and a part in the form of comb teeth extending radially towards the rotor.

3. Machine according to claim 2, in which the fixing part is held radially in an annular recess provided in the casing while being radially mobile in the recess, the damping system being disposed in the recess receiving the seal radially between the fixing part of the seal and the casing.

4. Machine according to claim 1, in which the damping system is a corrugated annular band configured to be deformed when the mechanical pressure increases.

5. Machine according to claim 1, in which the damping system is a washer comprising a plurality of braided fibres in contact between the fixing part of the seal and the seal support.

6. Machine according to claim 1, in which the damping system is a compression film encapsulated in a tight cavity of a segment containing oil.

7. Machine according to claim 1, in which the rotating machine is a multi-stage centrifugal compressor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other aims and features of embodiments of the invention will become apparent on reading the following description, given purely as a nonlimiting example, and with reference to the attached drawings in which:

[0023] FIG. 1 very schematically represents a rotating machine comprising a damping system;

[0024] FIG. 2 is a view of details of FIG. 1; and

[0025] FIGS. 3 to 5 represent three exemplary embodiments of a damping system.

DETAILED DESCRIPTION

[0026] FIG. 1 very schematically illustrates a rotating machine, referenced 10 overall and comprising a casing or a stator part 14 of the casing and a rotor 12 intended to be driven in rotation via a motor (not represented) mounted in said casing 14. The rotor 12 bears a plurality of impellers 16, of which only one is represented in FIG. 1. As illustrated, the rotor 12 is supported by a bearing 18 in the casing 14.

[0027] The rotating machine 10 can be a multistage centrifugal compressor or a gas turbine or any other rotating machine.

[0028] Seal rings 20 of labyrinth type are disposed on either side of each of the impellers. Each seal 20 is annular or semi-annular and comprises a fixing part 22 in a seal support secured to the casing 14 of the rotating machine and a part in the form of comb teeth 24 extending radially towards the rotor 12.

[0029] As illustrated in details in FIG. 2, the fixing part 22 is held radially in an annular recess 26 provided in the casing 14 while being radially mobile in said recess 26.

[0030] A damping system 28 is disposed in said recess between the casing 14 and the fixing part 22 of the labyrinth seal 20.

[0031] Generally, the damping system 28 is configured to allow a small displacement of the labyrinth seal, for example of the order of 100ths of millimetres in order to allow a mechanical damping behind the seal, at the level of its fixing on its support and thus guarantee an absorption of the energy from any disturbance coming from the gas flow, in order to stabilize the rotor and increase the efficiency of the centrifugal compressors operating under high pressure.

[0032] In other words, the damping system 28 does not allow a displacement of the labyrinth seal and thus makes it possible to avoid having the labyrinth seal come away in the event of a significant pressure generating a significant flow.

[0033] In the embodiment illustrated in FIG. 3, the damping system 28 is a corrugated annular band, for example made of steel, disposed in the recess 26 receiving the seal 20 between the fixing part 22 of the seal 20 and the casing 14 and configured to be deformed when the pressure increases and thus damp the labyrinth seal by absorbing the energy upon its deformation.

[0034] In the embodiment illustrated in FIG. 4, the damping system 28 is a washer comprising a plurality of braided fibres and disposed in the recess 26 receiving the seal 20 in contact between the fixing part 22 of the seal 20 and the casing 14 and configured to damp the labyrinth seal by absorbing the energy upon the deformation of each of the fibres. The washer is, for example, produced in a metal material, such as steel or copper. The displacement of the seal is then limited by mechanical abutments.

[0035] In the embodiment illustrated in FIG. 5, the damping system 28 is a compression film 30 encapsulated in a tight cavity 32 of a segment 34 containing oil. The displacement of the seal causes the deformation of the support. The damping is then provided by the crushing of the oil film contained in the interstice 30.

[0036] Generally, the damping system 28 makes it possible to obtain a damping of the labyrinth seal and thus modify the coefficient of the seal in terms of stiffness and of damping.

[0037] As will be understood, embodiments of the invention make it possible to place a mechanical damper behind the seal. Typically, in the known state of the art, the labyrinth seals are rigidly mounted in the casing of the compressor.

[0038] By virtue of the mechanical damping system according to embodiments of the invention, it is possible to absorb the disturbance energy coming from the gas flow and stabilize the rotor.

[0039] In addition, embodiments of the invention can be easily employed to improve the existing compressors, making it possible to reduce their cost price and servicing cost.

[0040] Finally, embodiments of the invention make it possible to produce integrated high-pressure compressors.

[0041] This written description uses examples to disclose the invention, including the preferred embodiments, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.