TOPSIDES VARIABLE SPEED DRIVE FOR LARGE PUMPS OR COMPRESSORS

Abstract

The invention provides a topsides drive for electric centrifugal pumps or compressors, distinctive in that the drive comprises an electric motor, an electric generator, a variable stepless coupling connecting the motor to the generator, at least one housing, and penetrators through a wall of the at least one housing.

Claims

1. A topsides drive for electric centrifugal pumps or compressors, the topsides drive comprising: an electric motor; an electric generator; a variable stepless coupling connecting the motor to the generator; at least one housing; and penetrators through a wall of the at least one housing.

2. The topsides drive according to claim 1, comprising a hydraulic variable stepless coupling.

3. The topsides drive according to claim 2, comprising: at least one housing for explosion proof encapsulation of the motor, the generator and the hydraulic coupling from the surroundings; explosion proof penetrators through the at least one housing wall; and wherein the drive has effect from about 2 MW or higher, such as 3 MW or higher or 6 MW or higher.

4. The topsides drive according to claim 2, wherein: the hydraulic coupling is a turbo coupling for which the transmitted power and speed is controlled by controlling the degree of filling with hydraulic fluid; and the turbo coupling comprises a scoop tube with controlled variable position for controlling the amount of an oil as hydraulic fluid in the coupling, thereby controlling the effect and speed of the coupling.

5. The topsides drive according to claim 2, wherein the hydraulic coupling comprises closed or shrouded impellers, a bypass line and a control valve for variable speed control.

6. The topsides drive according claim 1, comprising a cooling circuit with a cooler, arranged with a cooler inside the housing or with a cooler outside the housing.

7. The topsides drive according to claim 1, wherein the housing or housings are filled with oil or inert gas or both oil and inert gas.

8. (canceled)

9. (canceled)

Description

FIGURES

[0025] The drive of the invention is illustrated with two figures, of which;

[0026] FIG. 1 illustrates a drive of the invention with a turbo coupling and a common housing, with internal cooling, and

[0027] FIG. 2 illustrates another embodiment of a drive of the invention, with a displacement type hydraulic coupling, two housings and an external cooler.

DETAILED DESCRIPTION

[0028] Reference is made to FIG. 1, illustrating a drive 1 of the invention with a turbo coupling 2 and a common housing 3, with internal cooling (not shown). The drive comprises an electric motor M and an electric generator G, coupled together via the turbo coupling 2, which is a variable stepless coupling. The housing 3 is explosion proof, so called Ex safe and may comprise equipment for pressure control and detection of explosive gas (not illustrated). The drive comprises electric penetrators 4 to the motor and electric penetrators 5 from the generator to connected pumps and compressors (not illustrated). The speed and effect of the connected generator is controlled by controlling the filling level of hydraulic oil of the turbo coupling, which is controlled with pump 7 and filler tube 6. The hydraulic coupler comprises a cooler (not illustrated) and a reservoir (not illustrated) for full control of level and temperature, for coupling the generator to the motor as a stepless coupling from 0% to approximately 100% coupling depending on the filling level of oil. At full filling, the friction between the driving impeller, connected to a motor shaft, and the driven impeller, connected to a generator shaft, is at maximum, providing maximum coupling, of approximately 100%, At steady state operation, which will be the expected operation mode almost all the time, the coupling and hence the efficiency is close to 100%, for example 98% or better. Less than 2% is lost as heat, which must be tolerated or be handled by a cooler. Also, additional equipment and additional cooling will be required, for achieving reliability for the motor and the generator. Bearings need lubrication and cooling, and separate or common coolant and coolers will typically be required, in addition to instrumentation for control and monitoring. However, the skilled person will know how to use good engineering practice to ensure a reliable motor and generator, and details on this are therefore neither illustrated nor described.

[0029] FIG. 2 illustrates another embodiment of a drive 1 of the invention, with a displacement type hydraulic coupling, two housings and an external cooler. More specifically, the drive comprises a separate motor housing 3M and a separate generator housing 3G. The hydraulic coupling comprises closed or shrouded impellers, with a driving impeller in the motor housing and a driven impeller in the generator housing. Closed or shrouded impellers means that the flowing fluid for the coupling flows through the impellers via more or less closed volumes between the impeller blades, meaning that the rotating impellers are operating in a displacement like way, since the volumes between impeller blades are in substance confined or closed. This means that the flow of oil couples the impellers, not the friction in oil between closely arranged impellers as for a turbo coupling. This also means that the variable stepless speed or coupling must be controlled in a different way, more specifically by a bypass line 8 and a control valve 9, as illustrated, or in similar ways. For all steady state operation of connected pumps and compressors, the bypass line will preferably be closed for flow, for best efficiency. However, for transient operation, the bypass line will be gradually opened or closed for flow by operating valve 9. In the illustrated embodiment, the lines between the motor impeller and the generator impeller contains a cooler 10 and an oil reservoir 11.

[0030] The topsides drive of the invention can include any feature or step as here described or illustrated, in any operative combination, each such operative combination is an embodiment of the present invention. The use of the invention can include any feature or step as here described or illustrated, in any operative combination, each such operative combination is an embodiment of the present invention. For example, the invention also comprises a pressure boosting system comprising a topsides drive of 2 MW or higher drive effect, such as 3 MW or 6 MW or higher effect, coupled to at least one of: topsides pumps and compressors and subsea pumps and compressors, the subsea pumps or compressors are preferably located nearer than 40 km from the drive but can be located further away as discussed above.