Regenerative multi-stage compressor

Abstract

A compressor of the regenerative type configured to work at pressures exceeding 50 bars includes a motor, a magnetic drive coupling connected to the motor and adapted to transmit the rotary motion to a drive shaft, which is mechanically connected to the magnetic drive coupling, and two peripheral impellers mounted on the drive shaft.

Claims

1. A compressor of a regenerative type, configured to work at pressures exceeding 50 bars, comprising: a motor (101); a magnetic drive coupling (1) connected to said motor (101) and configured to transmit a rotary motion to a drive shaft (2), said drive shaft (2) being mechanically connected to said magnetic drive coupling (1); and a plurality of impellers (3, 4), each of said impellers being mechanically connected, directly or indirectly, to said drive shaft (2), each of said impellers (3, 4) being of a peripheral type and comprising a disc (31, 41) equipped with a set of blades (32, 42) mounted on one or both sides of the disc (31, 41), wherein said drive shaft (2) is supported by bearings (23) in at least two supports (21, 22), and wherein said plurality of impellers (3, 4) is mounted on said drive shaft (2) in a space included between said at least two supports (21, 22).

2. The compressor according to claim 1 further comprising a plurality of stages (A, B), each stage comprising a shell (A10, B10) made up of two half shells (A1, A2, B1) between which one of said impellers (3, 4) is mounted, wherein each one of said impellers (3, 4) rotates in a peripheral annular duct (5) obtained in said shell (A10, B10), and wherein said annular duct (5) communicates on one side with a gas suction mouth, coils forming an angle of about 360°, and ends adjacently to a delivery mouth.

3. The compressor according to claim 2, wherein said annular duct (5) is interrupted by a removable element that separates a low-pressure side, where said suction mouth is located, from a high-pressure side, where said delivery mouth is located.

4. The compressor according to claim 2, wherein said plurality of stages (A, B) are equal to each other but are oriented so as to be offset, and wherein between said shells (A10, B10) of said impellers (3, 4) there is an annular cavity (7) serving as an internal manifold to allow said stages (A, B) to be offset.

5. The compressor according to claim 1, further comprising sealing elements (8) mounted adjacently to the impellers (3, 4) to separate a scroll (V), in which said set of blades (32, 42) of the impellers (3, 4) rotates, from an inner chamber closer to said shaft (2) than the scroll.

6. The compressor according to claim 4, wherein said shaft (2) comprises a plurality of projections (24), included between said plurality of impellers (3, 4), and one or more sealing elements (25) constrained between said shaft (2), at a level of said plurality of projections (24), and said shells (A10, B10) or, vice versa, and wherein said compressor (100) comprises one or more sealing elements provided with teeth interposed between said shaft (2) and said shells (A10, B10) to create a dynamic barrier against gas recirculation.

7. The compressor according to claim 1, further comprising pairs of gaskets or O-rings placed side by side between fixed components of the compressor, a path being defined between said pairs of gaskets or O-rings for monitoring any leakages of a first one of the gaskets or O-rings that is connected to monitoring equipment.

8. The compressor according to claim 5, wherein each of said impellers (3, 4) is provided with holes or channels (81) that place said scroll (V), in which the blades (32, 42) of the impeller (3, 4) rotate, in communication with said inner chamber.

9. The compressor according to claim 5, wherein said discs (31, 41) of the impellers (3, 4) comprise one or more holes or ducts (82) that place said inner chamber (C) in communication with said bearings (23).

10. The compressor according to claim 1, wherein said at least two supports (21, 22) of the bearings (23) are provided with holes or ducts (83, 86) configured for passage of gas and to maximize gas flow through the bearings (23).

11. The compressor according to claim 1, wherein said shaft (2) is provided with an axial hole (84) for passage of gas along said shaft (2).

12. The compressor according to claim 11, wherein said shaft (2) comprises, at an upper end (2b) of the shaft, a passage (85) that places an inside of said axial hole (84) of the shaft (2) in communication with an inside of a containment cup (10) designed to contain said coupling (1), an internal magnet (11) being housed in said passage.

13. The compressor according to claim 5, further comprising a communication duct (87) which places said inner chamber in communication with a suction chamber of each of said impellers (3, 4) and through which gas coming from said coupling (1) flows into the suction chamber and mixes with inflowing gas.

14. The compressor according to claim 1, further comprising a tangential fan (9) located at a lower end of said shaft (2) and disposed to direct gas downwards.

15. The compressor according to claim 12, wherein an external surface (110) of said internal magnet (11) comprises one or more grooves (111) configured to guide a gas flow in an area of said containment cup (10).

16. The compressor according to claim 12, wherein said containment cup (10) containing the coupling (1) is made of metal, ceramic, polymeric compounds, or carbon fiber, and is arranged to have an axis parallel to or coinciding with an axis of said shaft (2) and facing towards an inside of the compressor (100) or in an opposite direction.

Description

[0046] FIG. 1 shows a sectional view of the new multi-stage compressor (100). According to the invention, said coupling (1) can be mounted in an opposite manner with respect to what is shown in FIG. 1, where the coupling (1), in particular, is mounted in such a way that the cup (10) containing the internal magnet (11) faces towards the inside of the compressor (100). In the opposite configuration, said containment cup (10) can be mounted in such a way that it faces the opposite direction.

[0047] FIG. 2 shows a detail of part of an impeller (3, 4) and of the sealing elements.

[0048] FIG. 3 shows a detail of the shaft (2) according to a possible embodiment.

[0049] FIG. 4 shows a sectional view of an impeller (3, 4), while FIG. 4a shows a detail of the same impeller, where it is possible to observe the communication channels (31) between the scroll (V) and the inner chamber.

[0050] FIG. 5 shows a sectional view of part of the compressor (100) schematically illustrating the gas recirculation path.

[0051] FIG. 6 shows a three-dimensional view of a tangential fan (9), while FIG. 7 shows the internal magnet (11) and its external covering (110) provided with a helical groove (111).

[0052] FIG. 8 shows a detail of the manifold (231) designed to contain the lubricant in the case where lubricated bearings (23) are installed in the compressor (100).

[0053] The invention is a compressor (100) particularly suited to operate with gases, comprising a motor (101), at least one coupling (1), preferably of the magnetic type, connected to said motor (101) and suited to transmit the rotary motion to at least one drive shaft (2).

[0054] Said drive shaft (2), mechanically connected to said coupling (1), is in turn supported by bearings (23) in at least two supports (21, 22), for example in proximity to the two opposite lower (2a) and upper (2b) ends.

[0055] The compressor (100) comprises at least two impellers (3, 4), each mechanically connected, directly or indirectly, to said shaft (2), and wherein said impellers (3, 4) are mounted on said shaft (2) in the space included between said two supports (21, 22).

[0056] Each one of said impellers (3, 4) is of the peripheral type, comprising a disc (31, 41) provided with a set of blades (32, 42) mounted on one or both sides of the disc (31, 41). The new compressor (100) thus comprises at least two stages (A, B), wherein each stage (A, B) comprises a shell (A10, B10), in turn constituted by half shells (A1, A2, B1) between which one of said impellers (3, 4) is installed.

[0057] Each one of said impellers (3, 4) rotates in a peripheral annular duct (5) obtained in said shell (A10, B10), wherein said annular duct (5) communicates on one side with a gas suction mouth (visible in FIG. 1 for the first stage A and indicated by A3), coils forming an angle of approximately 360° and ends in proximity to a delivery mouth (visible in FIG. 1 for the second stage B and indicated by B3).

[0058] For example, said annular duct (5) is interrupted by a preferably removable element that separates the low-pressure side, meaning the side where said suction mouth is located, from the high-pressure side, meaning the side where said delivery mouth is located. Said at least two stages (A, B) are substantially equal to each other but are oriented in such a way that they are offset, for example and preferably by 180° .

[0059] Between said two shells (A10, B10) of said impellers (3, 4) there is an annular cavity (7) with ducts for communication with the scrolls (V) of the impellers, serving the function of an internal manifold to allow said stages (A, B) to be offset.

[0060] One or more sealing elements (8) are mounted in proximity to the impellers (3, 4), mechanically locked and provided with a labyrinth outline, which separate the scroll (V), in which said set of blades (32, 42) of the impellers (3, 4) rotates, from an inner chamber that is closer to said shaft (2).

[0061] According to a first solution shown in FIG. 3, to form a dynamic barrier against gas recirculation, on said shaft (2), between said impellers (3, 4), there is a plurality of projections (24) that rotate against one or more sealing elements (25) constrained between said shaft (2), at the level of said projections (24), and said shells (A10, B10). In an alternative solution not shown in the figures, one or more sealing elements equipped with teeth are interposed between said shaft (2) and said shells (A10, B10).

[0062] According to the invention, in order to guarantee static sealing pairs of gaskets and O rings placed side by side are installed between the elements that make up the fixed parts of the compressor (100), a path for monitoring any leakages of the first O ring suited to be connected to monitoring equipment being created between said pairs of gaskets and O rings.

[0063] The gas recirculation path, which serves the function of guaranteeing the thermal balance inside the compressor (100), is schematically shown in FIG. 5. Supposing to start from the second stage (B), meaning from said lower impeller (3) farther from the coupling (1), the gas flows from the scroll (V) into said inner chamber, flowing through one or more holes or channels (81) created in said impeller (3) and placing said scroll (V) in communication with said inner chamber.

[0064] Said discs (31, 41) of the impellers (3, 4) are provided with one or more holes or ducts (82) that place said inner chamber in communication with said bearings (23), wherein said gas flows into said bearings (23) through said holes or ducts (82).

[0065] In a possible solution, said supports (21, 22) of the bearings (23) are provided with suitable holes or ducts (83, 86) for the passage of gas, designed to maximize the gas flow through the bearings (23) themselves.

[0066] The gas then flows into the shaft (2) through an axial hole, from its lower end (2a) to its upper end (2b) closer to the coupling (1).

[0067] In said upper end (2b) of the shaft (2) or in proximity to the same there is a passage (85) that places the inside of said axial hole (84) of the shaft (2) in communication with the inside of a containment cup (10) containing said coupling (1), in which at least one internal magnet (11) is housed.

[0068] As shown in FIG. 7, the external surface (110) of said internal magnet (11) is provided with one or more grooves (111) designed to guide the gas flow in the area of said containment cup (10). Said one or more grooves (111) are preferably helical in shape.

[0069] Said cup (10) containing the coupling (1) is made of metal, ceramic, polymeric compounds, carbon fibre or other materials.

[0070] The gas then flows through the upper bearings (23) and/or through further passages (86) obtained in said upper support (22) and reaches said inner chamber of the first stage (A). Said inner chamber (C) communicates with a suction chamber (A4) via a communication duct (87) through which the gas coming from said coupling (1) enters the suction chamber (A4) itself and mixes with the inflowing gas.

[0071] The compressor (100) preferably comprises also a tangential fan (9) positioned at the lower end of said shaft (2) and serving the function of directing the gas downwards.

[0072] According to the invention, furthermore, the new compressor (100) may comprise means for generating a further air flow intended to cool the top of the compressor (100), that is, the part where the external magnet (12) of the coupling (1) is located.

[0073] According to the invention, the external casing (13) of said external magnet (12) is provided with one or more holes or openings, conveniently protected by filtering caps that let air flow therethrough.

[0074] Furthermore, said external magnet (12) can be provided with an integrated fan, for example in the upper part of the external magnet (12) itself, which generates the desired flow in the hollow space (14) between the external magnet (12) and said external casing (13).

[0075] Therefore, with reference to the above description and the attached drawings, the following claims are expressed.