CENTRIFUGAL PRESSURE BOOSTER AND METHOD FOR MODIFYING OR CONSTRUCTING A CENTRIFUGAL PRESSURE BOOSTER

Abstract

The invention provides a centrifugal pressure booster, for pressure boosting liquids, multiphase fluid or gas, the pres sure booster comprising a liquid filled electric motor with a stator and a rotor, with a rotor stator gap between the rotor and stator, a pressure boosting part in the form of a pump or compressor operatively coupled to the rotor, and at least one housing, one fluid inlet and one fluid outlet. The pressure booster is distinctive in that it comprises a rotor stator gap coolant inlet pump, for enhancing the coolant flow through the rotor stator gap. The invention also provides a related method and use of a rotor stator gap coolant inlet pump.

Claims

1. A centrifugal pressure booster, for pressure boosting liquids, multiphase fluid or gas, the centrifugal pressure booster comprising: a liquid filled electric motor with a stator and a rotor, with a rotor stator gap between the rotor and stator; a pressure boosting part in the form of a pump or compressor operatively coupled to the rotor; and at least one housing, one fluid inlet and one fluid outlet; and wherein the centrifugal pressure booster comprises a rotor stator gap coolant inlet pump, for enhancing the coolant flow through the rotor stator gap.

2. The centrifugal pressure booster according to claim 1, wherein the centrifugal pressure booster is a subsea centrifugal pressure booster for pressure boosting liquids, multiphase fluid or gas at subsea locations, the centrifugal pressure booster further comprising at least one pressure housing and a coolant circulation pump arranged for pumping coolant through the gap and stator channels,

3. The centrifugal pressure booster according to claim 1, wherein the inlet pump is an impeller fastened to and arranged as an axial extension to laminations or a short circuiting ring of the rotor.

4. The centrifugal pressure booster according to claim 1, wherein the inlet pump comprises angled blades or vanes fastened to and arranged as an axial extension to laminations or a short circuiting ring of the rotor, or arranged on a rotor shaft adjacent the rotor stator gap.

5. The centrifugal pressure booster according to claim 1, wherein the rotor stator gap coolant inlet pump is a combined balancing ring and impeller, having outer diameter larger than the inner diameter of the rotor stator gap but smaller than the outer diameter of the rotor stator gap, the combined balancing ring and impeller has outlet for coolant directly into the rotor stator gap.

6. A method for modifying or constructing a centrifugal pressure booster, for pressure boosting liquids, multiphase fluid or gas, the centrifugal pressure booster comprising a liquid filled electric motor with a stator and a rotor, with a rotor stator gap between the rotor and stator, a pressure boosting part in the form of a pump or compressor operatively coupled to the rotor, one fluid inlet and one fluid outlet, and at least one pressure housing if the centrifugal pressure booster is for subsea operation, the method comprising: providing the centrifugal pressure booster with a rotor stator gap coolant inlet pump, for enhancing the coolant flow through the rotor stator gap.

7. The method according to claim 6, wherein a combined balancing ring and impeller is arranged as the rotor stator gap inlet pump, having outer diameter larger than the inner diameter of the rotor stator gap but smaller than the outer diameter of the rotor stator gap, the combined balancing ring and impeller being arranged having outlet directly into the rotor stator gap and preferably it is fastened to and arranged as an extension to laminations or a short-circuiting ring of the rotor, as a ring on a rotor shaft.

8. (canceled)

Description

FIGURES

[0022] FIG. 1 illustrates a subsea pressure booster of the invention, with a combined balancing device and rotor stator gap circulation impeller.

[0023] FIG. 2 is an illustration of a detail of a subsea pressure booster of the invention.

DETAILED DESCRIPTION

[0024] Reference is made to FIG. 1, illustrating, in longitudinal section, a subsea pressure booster 1 of the invention, with a combined balancing device and rotor stator gap circulation impeller 2. FIG. 2 illustrates the motor part of the subsea pressure booster of FIG. 1 in more detail. Accordingly, in the illustrated embodiment, the rotor stator gap coolant inlet pump is a combined impeller and balancing device. In some otherwise identical or similar embodiments, the rotor stator gap coolant inlet pump is not a combined impeller and balancing device. FIG. 2 illustrates the impeller 2 in detail, and it can be seen clearly that the impeller comprises a number of blades 2b. The impeller is fastened to the rotor 3 at the inlet of the rotor stator gap, as an axial extension of the rotor laminations/short circuit ring. The impeller has outer diameter just smaller than the outer diameter of the rotor stator gap, to ensure clearance at different temperatures. The outlet outer diameter of the impeller hub, not the blades, is identical to the outer diameter of the short circuiting ring and rotor laminations. Around the rotor 3 is a stator 5, between the rotor and stator is the rotor stator gap 6, which is an annular volume with smooth radial inside and outside surfaces, without vanes increasing the friction for flow. Furthermore, the figure illustrates a coolant circulation pump 7 arranged for pumping coolant through said gap and stator channels, in the form of a common circulation impeller 7 feeding both stator channel and rotor stator gap coolant flow. A common, prior art type circulation impeller 7 is illustrated, and the rotor stator gap cooling flow 8 and the stator channels cooling flow 9.

[0025] The centrifugal subsea pressure booster of the invention can include any feature or step as here illustrated or described, in any operative combination, each such combination is an embodiment of the invention. The method of the invention can include any feature or step as here illustrated or described, in any operative combination, each such combination is an embodiment of the invention. The use of the invention can include any feature or step as here illustrated or described, in any operative combination, each such combination is an embodiment of the invention.