System comprising a cooling device for a machine enclosed in a pressurized casing

FIELD OF THE INVENTION

Embodiments of the invention relate generally to a machine enclosed in a pressurized casing.

In particular, embodiments of the invention relate to a cooling device for a machine enclosed in a pressurized casing, and more particularly to removable sealing elements of a cooling device for circulation of a coolant medium through the pressurized casing.

Notably, integrated motor-compressor units are known, wherein both the electric motor and the compressor are hermetically enclosed in a cylindrical casing.

Integration of a cooling device in such a configuration requires safety precautions related to differential pressure between the cooling medium, water for example, and the pressurized gas inside the casing. Notably, the pressurized gas tends to move towards the lower-pressure cooling medium, the mixture exposing the cooling system to a potential risk of over-pressure.

DESCRIPTION OF RELATED ART

A usual integration consists in welding the cooling device to the inside of the pressurized casing.

Nevertheless, manufacturing is complicated and, considering the location of the welds, it raises issues of accessibility. Besides, welding is difficult on cast iron casing.

According to another commonly used solution, O-rings are positioned between a cooling j acket and the casing. Although it is simple, this approach requires a frequent and complicated maintenance for replacing the j oints which involves entirely disassembling the system. Moreover, a potential damage of the O’ ring during the assembly would be identified only after full assembly which involves again entirely disassembling the system. There is a need to avoid at least some of the previously mentioned drawbacks, especially by preventing a mixture between the coolant medium circuit and the pressurized gas inside the casing.

SUMMARY

According to one aspect, a system comprising a pressurized casing delimiting an enclosure for at least one machine and a cooling device is proposed.

The cooling device includes: a cooling j acket located inside the pressurized casing; at least one removable sealing element between the cooling j acket and one of a cooling medium inlet or outlet pipe located outside the pressurized casing, wherein the removable sealing element comprises inner and outer cylindrical pieces extending coaxially through the casing and a flange attached to the casing for maintaining the cylindrical pieces, the inner cylindrical piece allowing the cooling medium circulation between the cooling j acket and one of the cooling medium inlet or outlet pipe, the removable sealing element comprising a cooling medium sealing barrier including a sealing device located between the inner cylindrical piece and the cooling j acket, and a gas sealing barrier including a sealing device located between the outer cylindrical piece and the cooling j acket.

Preferably, the inner and outer cylindrical pieces are kept apart from each other so as to form a gap connected to a vent leading to the outside of the pressurized casing.

Advantageously, the removable sealing element may comprise an adaptation piece, located between the casing and the flange, and maintaining the inner and outer cylindrical pieces.

Advantageously, the vent may be located in the adaptation piece.

Preferably, the gas sealing barrier further includes a sealing device located between the outer cylindrical piece and the casing. Preferably, the gas sealing barrier further includes a sealing device located between the inner cylindrical piece and the adaptation piece, or located between the inner cylindrical piece and the flange if the removable sealing element does not include an adaptation piece. Or located between the inner cylindrical piece and the casing.

Advantageously, the cooling device comprises: a first removable sealing element for the cooling medium circulation between the cooling j acket and a cooling medium inlet pipe located outside the pressurized casing, and a second removable sealing element for the cooling medium circulation between the cooling j acket and a cooling medium outlet pipe located outside the pressurized casing.

According to one embodiment, the cooling j acket and the inner cylindrical piece are attached by complementary screw-threads so as to form a cooling medium sealing barrier between the inner cylindrical piece and the cooling j acket.

Advantageously, the cooling j acket may comprise two independent upper and lower parts, enclosing a cooling circuit and welded one another to their extremities.

According to an alternative embodiment, the cooling j acket can be made by additive manufacturing.

According to another alternative embodiment, the cooling j acket can be made by casting process.

Besides, the pressurized casing may enclose at least one of the following machines : a turbine, an electric generator, a compressor and an electric driver.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages and features of the invention will appear on examination of the detailed description of embodiments, in no way restrictive, and the appended drawings in which :

[Fig 1 ] represents an embodiment of a system compri sing a cooling device for a machine enclosed in a pressurized casing according to the invention; [Fig 2] is a detailed view of a removable sealing element according to an embodiment of the invention, comprising an adaptation piece;

[Fig 3 ] is a detailed view of a removable sealing element according to another embodiment of the invention;

[Fig 4] is a detailed view of a removable sealing element according to another embodiment of the invention, including a screw- thread sealing; and

[Fig 5 ] represents another embodiment of a system comprising a cooling device for a machine enclosed in a pressurized casing according to the invention, comprising a passage for power supply cables.

DETAILED DESCRIPTION

Embodiments herein discloses arrangements of a compressor cooling system comprising at least one removable sealing element for cooling medium circulation in a cooling device extending between the interior and the exterior of a pressurized casing.

The removable sealing element compri ses at least one cooling medium sealing barrier and one gas sealing barrier preventing the mixture between the cooling medium flowing in the cooling circuit and the gas contained on the pressurized casing.

Reference is made to figure 1 which represents an embodiment of a system 1 compri sing a pressurized casing 2 delimiting an enclosure for at least one machine 3 and a cooling device 4.

In the illustrated example, the machine 3 is a motor compressor unit. However, the pressurized casing encloses at least one of the following machines : a turbine, an electric generator, a compressor and an electric driver

The pressurized casing 2 extends about a central axis A which is coincident with an axis of rotation of the motor compressor unit.

The cooling device 4 includes a cooling j acket 5 located inside the pressurized casing 2, preferably against the inner surface of the pressurized casing 2. As an example, the illustrated cooling j acket 5 comprises two independent upper and lower parts, respectively 5 a and 5b, enclosing a cooling circuit 6. The upper and lower parts 5a and 5b are welded one another to their extremities by welds 7 and 8.

According to alternative embodiments, the cooling j acket 5 can be made by additive manufacturing or can be made by casting process.

The cooling circuit 6 may extend as a coil within the cooling j acket 5.

Besides, in the illustrated example, the cooling medium is water.

The cooling device 4 further comprises at least one removable sealing element between the cooling j acket 5 and one of a cooling medium inlet or outlet pipe located outside the pressurized casing 2.

Preferably, the cooling device 4 includes two removable sealing elements, a first removable sealing element 9a for the cooling medium circulation between the cooling j acket 5 and a cooling medium inlet pipe 10 and a second removable sealing element 9b for the cooling medium circulation between the cooling j acket 5 and a cooling medium outlet pipe 1 1 .

The cooling medium coming from the cooling medium inlet 10 may thus penetrate the pressurized casing 2 passing through the first removable sealing element 9a, may circulate inside the cooling j acket 5 and then get out the pressurized casing 2 passing through the second removable sealing element 9b towards the cooling medium outlet 1 1.

Each removable sealing element comprises inner and outer cylindrical pieces, respectively 12 and 13 , extending coaxially through the pressurized casing 2, in an opening provided for this purpose, respectively 14 and 15 for the removable sealing elements 9a and 9b .

In another embodiment, inner and outer cylindrical pieces 12 and 13 can also be merged in a single element. In this case, a vent hole between the seals is drilled.

The inner cylindrical piece 12 allows the cooling medium circulation between the cooling j acket 5 and one of the cooling medium inlet or outlet pipe 10, 1 1. Advantageously, for safety precaution, the inner and outer cylindrical pieces 12, 13 are kept apart from each other so as to form a gap 16 connected to a vent 17, vi sible in Figure 2, leading to the outside of the pressurized casing 2. In case of leaks through this vent 17, one may quickly identify if a sealing element does not operate properly.

A flange 18 is attached to the pressurized casing 2 for maintaining the cylindrical pieces 12 and 13. For example, the flange

18 may be attached by screws. An opening is provided through the flange 18 for the circulation of the cooling medium between the removable sealing element 9a, 9b and the cooling medium inlet or outlet pipe 10, 1 1.

The embodiment of removable sealing element illustrated in Figures 1 and 2 comprises an adaptation piece 19. The adaptation piece

19 is an intermediate piece located between the pressurized casing 2 and the flange 18, and maintaining the inner and outer cylindrical pieces 12, 13 in position within the pressurized casing 2. As an example, the flange 18 may be attached to the pressurized casing 2 by screws passing through the adaptation piece 19.

As illustrated, the vent 17 may be located in the adaptation piece 19.

According to an alternative embodiment shown in Figure 3 , the flange 18 may be configured to replace the adaptation piece 19. In this case, the flange 18 may comprise the vent 17. As shown in Figure 3 , the upper part diameter of the inner cylindrical piece 12 can be advantageously adapted to cooperate with the flange 18.

Besides, each removable sealing element 9a, 9b comprises a cooling medium sealing barrier including a sealing device 20 located between the inner cylindrical piece 12 and the cooling j acket 5, preventing the leaking of the cooling medium from the cooling circuit 6 to the outside of the inner cylindrical piece 12.

Each removable sealing element 9a, 9b further comprises a gas sealing barrier including a sealing device 21 located between the outer cylindrical piece 13 and the cooling j acket 5, preventing the leaking of the gas from the pressurized casing 2 to the inside of the outer cylindrical piece 13 .

In the examples illustrated in the figures, the sealing devices of the cooling medium sealing barrier and the gas sealing barrier include a gasket, preferably O-ring.

This forms a double sealing barrier preventing both cooling medium and gas to mix.

The gas sealing barrier further includes a sealing device 22, preferably located between the outer cylindrical piece 13 and the pressurized casing 2.

The cooling medium sealing barrier of each removable sealing element 9a, 9b of the illustrated embodiment also includes a sealing device 23 located between the inner cylindrical piece 12 and the adaptation piece 19 as illustrated in figure 2. The sealing device 23 can also be located between the inner cylindrical piece 12 and the flange 18 as illustrated in figure 3 , or located between the inner cylindrical piece 12 and the casing 2 (not illustrated here), if the removable sealing element 9a, 9b does not include an adaptation piece 19.

Each of the sealing devices 20 and 23 of the cooling medium sealing barrier is located at one end of the inner cylindrical piece 12, and each of the sealing devices 21 and 22 of the gas sealing barrier is located at one end of the outer cylindrical piece 13.

The inner cylindrical piece 12 may include an upper rim 24 cooperating with the adaptation piece 19 or the flange 18 if no adaptation piece 19 is provided, in order to be well positioned and well aligned within the opening 14, 15 of the casing 2.

Referring now to Figure 4 which depicts another embodiment of the cooling medium sealing barrier, the cooling j acket 5 and the inner cylindrical piece 12 are attached by complementary screw-threads so as to form the sealing device 20 of the cooling medium sealing barrier between the inner cylindrical piece 12 and the cooling j acket 5. The sealing device may be for example a gas thread or NPT thread (“National Pipe Thread”, NPT). Furthermore, the pressurized casing 2 of the system 1 may also be provided with an opening 25 for the passage of power supply cables from the machine 3 to a terminal box 26, visible in Figure 5.

In this embodiment, the cooling j acket 5 is advantageously provided with a passage 27.

In order to protect the power supply cables against the gas, an outer cylindrical piece 13 and, for example, an adaptation piece 19, may be inserted within the opening 25 of the pressurized casing 2.

Referring now to Figures 1 , 2, 3 , 4 and 5, one operating cycle of the system 1 will now be described. In operation, cooling medium from cooling medium inlet pipe 10 can penetrate the interior of the pressurized casing 2 through the inner cylindrical piece 12 of the first removable sealing element 9a and circulates through the cooling circuit 6 of the cooling j acket 5 for cooling of the motor compressor unit 3.

The first removable sealing element comprises a cooling medium sealing barrier including a sealing device 20 located between the inner cylindrical piece 12 and the cooling j acket 5. Besides, a gas sealing barrier including a sealing device 21 i s located between the outer cylindrical piece 13 , which extends coaxially of the inner cylindrical piece 12, and the cooling j acket 5.

The cooling medium sealing barrier and the gas sealing barrier of the system prevent the risk of over-pressure by preventing the mixture between gas and cooling medium.

In a similar way, cooling medium can then flow back to the exterior of the pressurized casing 2, circulating through the second removable sealing element 9b, towards the cooling medium outlet pipe 1 1.

The configuration of the removable sealing elements 9a, 9b an enable a fast and easy maintenance.