CS9100115A2 - Dry sealing for rotating part and rotating machine that contains such sealing - Google Patents

Abstract

Of the stationary body (8) and rotating body (4) forming the seal, one (8) is provided with an internal environmental-control circuit (9, 13). The invention applies particularly to the manufacture of turbo- machinery. <IMAGE>

Description

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WHAT

The seals of the seal 54 are sealed to form a seal.

Oblast_technik £

BACKGROUND OF THE INVENTION The present invention relates to a seal for rotating parts, and more particularly to a seal of the type referred to as a dry seal. In order to safely operate a series of rotating machines using such a seal, effective air conditioning of such a seal is required, especially for the necessary seal maintenance and to prevent deformation or destruction which may be caused by heating or cooling the seal excessively.

Various solutions are known for providing a seal on the casing through a rotary shaft. A labyrinth with a reduced clearance can be used for non-hazardous gas. In the case of hazardous gases, salt film seals or mechanical seals may be used. The circulation of the oil of the fixed and movable rings of the seal ensures air conditioning either by removing the heat generated by its squeezing or by supplying the necessary cooling to maintain the temperature of the sizing compatible with the sealing function. However, such an air-conditioning method is not possible in the case of a dry seal which is disposed of such an oil circulation. In strict conditions of use, such as dry seals operating at high speeds, high pressure, or where the surface of the rotating parts, which are in contact with the hot gas, becomes heat-forming and the inner temperature of the seal is such that it can cause component destruction and to cause such a serious failure of the turbine machine.

This danger is particularly serious in working procedures that require three sealing interfaces for safety reasons. The seal comprises three inner chambers which follow each other within the shell containing the gas to be covered up to the ambient air. Partitioning between the interior of the shell and the first chamber, between two successive chambers and between the last chamber and the air are each formed by a rotating sealing ring co-operating with the fixed sealing ring. An auxiliary gas is injected into the intermediate chamber and enters the skull escaping into the first and third chambers from which it is discharged. Heat dissipation is partly caused by gas leaks at the sealing interfaces. However, it should be noted that the gas removed from the first chamber is purified by the gas to be covered in the shell and must in certain cases be further processed.

A known solution for dissipating heat from such a seal is to increase the leakage of gas through the seal. However, this is dangerous because the leakage of gas in the casing, which allows heat to dissipate, can cause problems of utilization safety, and furthermore, too large an axial gap between the fixed and rotatable sealing rings reduces the axial stiffness of the gaseous film that circulates radially within this limit -re. Due to various mechanical and aerodynamic stresses, this can result in harmful contact between the fixed ring and the rotating ring. Such touches carry the risk of inducing a definite loss of tightness.

The problem of cooling, although substantial and often occurring, is not the only one to consider. Indeed, in some devices, the seal is placed in a very cold environment and hot gas is injected into the sealing interface. In this case, if the heat generation is not sufficient, cooling of the gas may occur, resulting in the formation of a liquid phase / condensation and consequently destruction at the seal level, the scaffold to prevent the gas from cooling down would increase its flow rate, but also here the disadvantages similar to those explained above are found. 3

In particular, it is an object of the present invention to provide a simple dry seal for a rotating part allowing a more reliable operation of the rotating machine without generating or increasing fluid leakage through the seal and without the risk of contaminating the auxiliary fluid with the fluid to be charged. £. £ £ έ: £ 1 £ L1 §. i. 2 E £ _ ii Z 2

SUMMARY OF THE INVENTION The subject of the invention is a dry seal for a rotatable portion comprising a fixed subassembly supported by a fixed portion, wherein the rotatable portion is rotated about an axis, and a rotating subassembly supported by said rotating member and interacting with said fixed subassembly to prevent fluid to rotate. between the fixed and the rotating parts, each of the two parts, i. a rigid subassembly or rotatable subassembly, itself comprising a fixed or rotatable body supported by said rigid member or rotatable member against said rotatable or fixed body of said second subassembly, and at least a first and second fixed seal ring or rotatable sealing lip supported by said axes with said fixed or rotatable body for cooperation with said first and second sealing rings, rotatable or fixed second subassemblies, such that at least one flow of said fluid to be covered is constrained, while at least one intermediate chamber comprising two main walls formed by a fixed body is formed and a rotating body and two outer walls formed by at least one of said rings, i.e. solid or rotating, which according to the invention is characterized in that at least one of said bodies, i. the fixed body or rotatable body includes an air conditioning circuit housed within the body allowing circulation of the air conditioning fluid to form an air-conditioned and air-conditioned body, thereby airing one of said sealing rings and at least partially said second rotating body or fixed body. - 4 -

According to a further feature of the invention, the seal is characterized in that said air-conditioned and air-conditioning body comprises air-conditioning vanes extending into said intermediate chamber from said main wall formed by said body, so that it climatizes the internal fluid contained in said chamber so that said fluid itself can cure. said at least one of said sealing rings and / or said second rotating body being a non-locking body. Furthermore, the seal may be characterized in that the second and third of said fixed rings and rotary rings follow each other in the longitudinal direction, which is the direction of the axis and which of the sealing direction of the seal, the inner air conditioning circuit comprising feed and return channels oriented most of the length of the seal, supply and return connections which allow these channels to be connected to the external circuit of the air-conditioning fluid and which are mounted in an attached surface that cuts the longitudinal surface of said air-conditioned body, and further comprises internal connection channels for connecting said supply channels to return channels adjacent the extreme longitudinal the area of said gasket, opposite the attachment face. Said rotatable part may be a shaft carrying said rotating body, said fixed body enclosing said rotating body and forming said air body.

The invention further relates to a rotating machine comprising a working device rotating in a housing for driving or driving it by a fluid fed in said housing, rotating a shaft extending through said housing for supporting said working means and penetrating said housing, at least one bearing for supporting said shaft, a lubricating circuit comprising feed tubes and return tubes for lubricating said bearing by means of a lubricating fluid, and at least a one-way seal surrounding said shaft with its passage through said housing to dump said fluid to be covered, said machine being characterized in that said dry seal is as described above of the type according to the first paragraph of the characteristic of the invention and the air-conditioning fluid is a lubricating fluid of the type mentioned. Further, the invention relates to a rotating machine comprising a working device rotating in a housing for driving or to be driven by a liquid fed in the housing, wherein a fluid of this fluid defines a zone of relatively high pressure and a zone of relatively low pressure, rotatable a shaft extending through said housing for supporting said working means extending through said housing, and at least one dry seal enclosing said shaft when passing said said housing to said fluid to be covered, said dry seal being a seal according to the first paragraph the characteristics of the invention, said air-conditioning fluid is formed by said fluid to be covered, said air-conditioning circuit within said air-conditioned body being fed by an external power-supply circuit comprising a withdrawal tube the liquid to be covered in said relatively high pressure region and the return tube to said relative low pressure region. The seal of the invention makes it possible to ensure tightness between the intermediate and fixed portions under the conditions of relatively single drying and to provide a reliable dry path function for creating or increasing fluid leakage through the seal and without contamination of the auxiliary fluid by the liquid to be covered. FIGS

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail in the following non-limiting embodiments, with reference to the accompanying drawings, in which: FIG. 2 is a cross-sectional view taken along line II-II of FIG. 3 is an axial sectional view of a rotary machine comprising such seals; and FIG. 4 is an axial section through a second rotating machine comprising such a seal. EE2Y

Referring to FIG. 1, the gasket of the present invention comprises a fixed sub-assembly 7, 8 supported by a part 3 fixedly disposed relative to the rotating part 1 rotating about the axis A. It further comprises a rotatable sub-assembly 4, 5 carried by said rotating part and operating with a fixed subassembly to prevent the fluid to be deflected from flowing to the other. Each of the two subassemblies, i.e., the fixed subassembly and the rotatable subassembly, comprising a corresponding solid body 8 and a rotatable body 4 carried by a corresponding rigid member 3 or a rotatable member 2 disposed against said rotatable or fixed subassembly portion. Further, the first and second fixed sealing rings 7 and 7A are provided in the case of a fixed sub-assembly and a rotary sealing ring 5 and 5A in the case of a rotary subassembly. The fixed subassembly of the present example comprises a first, second and third fixed rings 7, 7A and 7B. Each of them cooperates with a rotating associated ring 5, 5A, 5B, which is located in the second said subassembly. Such rings are arranged to at least limit the flow of fluid to be retained and form at least one intermediate chamber 14 that includes corresponding main walls 10, 17 formed by said rigid and rotatable bodies, and two extreme walls. the walls formed by one of at least one of said first rings comprising a fixed and rotatable ring, and the other by a second 7A of second rings comprising a fixed and rotatable ring. In the case of an exemplary embodiment of the seal, the shaft 1 of the rotating machine is more particularly rotatable. It is oriented in the direction of the longitudinal axis A of rotation. The fixed part is a housing 3 which forms part of the housing of the machine and forms a housing Z for sealing. 7

The rotating body consists of a ring 4 with a shoulder on one of its ends. The shaft 2 passes through its axial recess, which provides the assembly with perfect positioning. The outer surface of the ring is provided with three rotatable sealing rings 5, 5A, 53 which are driven to a pivoting motion by a pin or any other known element, and are spaced apart from each other by spacers 6, 6A and 6B. Each rotary ring cooperates with a corresponding ring 7, 7, 7 and 73 to form a gas barrier for the gas to be covered. Thus, the first, second and third barriers are formed by the pairs of rings 7 and 5, 7a and ZS3 53. The two intermediate chambers 22 and 15 are delimited. In addition to the fixed rings 7, 7 ' and 73, the annular subassembly comprises a body 8 which forms the outer envelope of the seal.

According to the invention, at least one of said fixed body b and said rotating body 4 comprises an air-conditioning circuit 9, 9A and 13, which extends within said body and permits circulation of said air conditioning fluid. Body C air-conditioned. Thereafter, at least one of said sealing rings 7, 7A, 73 is air conditioned.

According to a preferred embodiment, said closure body 8 comprises air conditioning vanes 21 (extending into said intermediate chambers 12 and 15 from said main wall 16 formed by said body), thereby air conditioning the internal fluid contained in said chambers so that said liquid then climatizes at least one of said chambers. one of said sealing rings 5A, 53 and / or the second of said fixed body 8 and the rotating body 4.

The internal air conditioning circuit comprises a supply duct 9 and a return duct 9A oriented along the majority of the distance of said seal. Further, the circuit includes an inlet connection 16 and a reversible connection 211 allowing the ducts to be connected to the external air-conditioning fluid and disposed on one connecting side δΑ, which is the extreme longitudinal side of said air-conditioned body. Further, it comprises internal connection channels for connecting said supply channels to return channels adjacent to the outer surface of the area 8B of said seal oppositely to said bonding surface. Although three sealing assemblies have been shown in FIGS. 2 and 3, it will be appreciated that all mounting shapes may be used, wherein the seal may comprise one or more sealing interconnecting elements.

FIG. 3 shows a rotating machine according to the invention comprising a working device 22 rotating in a housing 3C for driving or for driving it by a liquid fed in said housing. Further, the rotating shaft 1 extending through the housing for supporting these working devices and extending from the housing further comprises two bearings 24 and 26 for supporting the same shaft and a lubricating circuit comprising the feed tube 28a of the return tube 29 for lubrication these bearings by lubricating the fluid. Further, the machine comprises two dry seals 2G and 21 surrounding said shaft 1 in its passages through said shell to cover said fluid to be covered. In this machine, the gaskets 20 and 21 of the gasket are of the type described above, wherein the air-conditioning fluid is formed by said gassing fluid.

Alternatively, it is possible to use an air conditioning fluid which is completely independent and comes from an external source. FIG. 4 illustrates a second rotary machine comprising a working device 72 rotating in a housing 80 for driving or to be driven by a fluid to be covered in said housing, the pressure of said fluid defining relatively high pressure regions 90 and a relatively low pressure area 92. The apparatus includes a rotating shaft 51 extending through the housing of said working means and extending to the ends of said housing. It further comprises two bearings 7d and 76 for supporting the shaft. Finally, the machine comprises two dry seals 70 with a ující1 surrounding said shaft in its passages with said enclosure for introducing fluids which are thickened. In this machine, the gaskets 70 and 71 of the gasket are of the type described above, wherein said air-conditioning fluid comprises said fluid to be covered. The internal air conditioning circuit inside the air conditioner is formed for this purpose by an external supply air conditioning circuit comprising a fluid removal tube 91 to be removed in said relatively high pressure zone 90, and a tube 93 for returning it to said low pressure zone 9 2.

Claims (4)

sdvoX & t PRAHA íjŽKná 2f cC v A dry seal for a rotating part, comprising a fixed sub-assembly supported by a fixed part, by means of which the rotatable part is rotated about an axis, and a rotatable sub-assembly carried by said rotatable part; interacting with said fixed subassembly to prevent the fluid to be covered flowing between fixed and rotatable portions, each of the two parts, i.e. the fixed subassembly or the rotatable subassembly itself comprises a fixed or rotatable body carried by said fixed part or rotatable against said rotatable or a fixed body of said second subassembly, and at least a first and second fixed seal or rotatable sealing rings supported coaxially by said surrounding or said co-operating or rotatable body with said first and second sealing rings, rotatable or fixed second subassemblies, so as to be at least limiting the flow of said fluid, kt It is to be covered, at the same time as forming at least one intermediate chamber, which comprises two outer walls formed by a fixed body and a rotatable body formed by at least one of said rings, i.e. fixed or rotatable, characterized in that at least one of said bodies , ie. the fixed body (3) or the rotating body (4 Z) comprises an air conditioning circuit (9A, 9A, 11J) embedded within the body and permits circulation of the air conditioning fluid (Z8Z) to form an air-conditioned air conditioning body (WZ) which then cools one of the said sealing rings (7) , 7A, 7BZ and at least partially a second rotating body Z4Z or a fixed body. Seal according to claim 1, characterized in that said air-conditioned and air-conditioning body Z8Z comprises air-conditioning vanes Z11Z extending into said intermediate chamber Z1Z from said main wall Z1Z formed by said body, so as to air the inner fluid contained in said chamber The fluid itself itself has at least one of said sealing rings Z5A, 53Z or said second rotating body Z4Z or fixed body. 11 Seal according to claim 1, characterized in that the second and third fixed rings (7, 7A, 73) and the rotating rings (5, 5A, 5B) follow one another in the longitudinal direction, which is the direction of the axis (A) and which is the lengthwise the direction of the seal, wherein the internal air conditioning circuit comprises supply / return channels (977) oriented in the majority of the lengthwise seal, feed / 737 ε reversible; 3, 7 of the connection which allows these channels to be connected to the external circuit of the air-conditioning fluid and which are disposed in the attachment surface (8A), which extends beyond the longitudinal surface of said air-conditioned body (2), and further comprises internal connecting channels / 13 / for connecting said feed channels with return ducts close to the end longitudinal surface (83) of said seal, opposite to the attachment surface. characterized in that said supporting body (8) surrounds said rotatable body (1). 4. The rotatable sealing member is a shaft and said fixed body and comprises the aforementioned machine comprising a working device rotating in the housing to drive or to be driven by the fluid in the housing rotating. A shaft extending through said housing for supporting said working devices and penetrating said housing, and thus for supporting said shaft, a lubricating circuit comprising a supply tube (387) and a return tube (297) for lubricating said bearing with lubricating means fluid, and at least one dry seal (2 ', 2') surrounding said shaft (1) as it passes through said sheath for said liquid to be covered, characterized in that said dry seal (20) is a seal and the air-conditioning fluid is formed by said lubricating fluid. A squeezing machine comprising a working device (77) rotating in a housing (37) for driving or to be driven by a fluid to be covered in said housing, the pressure of said fluid defining a zone a relatively high pressure (90) and a relatively low pressure zone (92), a rotatable shaft (51) extending through the housing for non-sowing these working devices and passing through said housing, and at least one dry seal (70, 71) surrounding said shaft as it passes through wherein said dry seal (70, 71) is a seal according to claim 1, said air conditioning fluid being formed by said fluid to be covered, said air conditioning circuit within said air conditioned body it is powered by an external supply air conditioning circuit containing the tubes (91) for discharge the said fluid to be covered, in said relatively high pressure region (90), and the tubing for said relatively low pressure region (92).