US5562405A — Multistage axial flow pumps and compressors

Claim 1

Independent Claim 67 words

An axial flow pump for use in pumping a multiphase fluid, the pump comprising at least one stage having a rotor for imparting whirl in one direction and two stators for imparting whirl in the opposite direction to maintain entrainment of the gas phase of the fluid within the liquid phase, one stator being upstream of the rotor and the other stator being downstream of the rotor.

Claim 2

Dependent Claim 67 words

An axial flow pump for use in pumping a multiphase fluid, the pump comprising at least one stage having a rotor for imparting whirl in one direction and two stators for imparting whirl in the opposite direction to maintain entrainment of the gas phase of the fluid within the liquid phase, one stator being upstream of the rotor and the other stator being downstream of the rotor.

Claim 3

Dependent Claim 18 words

The pump of claim 1, wherein the rotor has a cylindrical hub and rotates within a cylindrical housing.

Claim 4

Dependent Claim 19 words

The pump of claim 1, wherein means for diffusion of the fluid is provided after the last pump stage.

Claim 5

Dependent Claim 42 words

The pump of claim 1, wherein said at least one stage includes two stators, one upstream and one downstream of the rotor, the rotor arranged to induce whirl in one direction and the stators arranged to induce whirl in the opposite direction.

Claim 6

Dependent Claim 20 words

The pump of claim 1, wherein the rotor is in the form of an impeller mounted on a rotatable shaft.

Claim 7

Dependent Claim 28 words

The pump of claim 1, wherein a stator is provided downstream of the rotor and has bull-nosed vanes capable of tolerating a wide range of flow incidence angles.

Claim 8

Dependent Claim 22 words

The pump of claim 1, wherein the rotor is in the form of a series of impellers mounted on a rotatable shaft.

Claim 9

Dependent Claim 17 words

The pump of claim 1, wherein the rotor has a fluid flow coefficient of less than 0.4.

Claim 10

Dependent Claim 18 words

The pump of claim 8, wherein the rotor has a fluid flow coefficient of between 0.15 and 0.25.

Claim 11

Dependent Claim 71 words

A multistage axial flow pump or compressor comprising at least one stage including a rotor for imparting whirl in one direction and an inter-stage stator for imparting whirl in the opposite direction and having a plurality of vanes defining curved arcuate passages therebetween, the cross-sectional area of each passage being substantially constant along the whole length of the curved arc of each passage whereby the stator produces little or no diffusion.

Claim 12

Dependent Claim 71 words

A multistage axial flow pump or compressor comprising at least one stage including a rotor for imparting whirl in one direction and an inter-stage stator for imparting whirl in the opposite direction and having a plurality of vanes defining curved arcuate passages therebetween, the cross-sectional area of each passage being substantially constant along the whole length of the curved arc of each passage whereby the stator produces little or no diffusion.

Claim 13

Dependent Claim 18 words

The pump of claim 10, wherein the rotor has a cylindrical hub and rotates within a cylindrical housing.

Claim 14

Dependent Claim 68 words

The pump of claim 10, wherein the stator is configured such that, at or near the design duty flow, the fluid is discharged from the stator with an absolute velocity which has substantially the same axial component as the fluid entering the stator, and has a whirl component of velocity which is substantially the same as the whirl component entering the stator, but in the opposite rotational direction.

Claim 15

Dependent Claim 19 words

The pump of claim 10, wherein means for diffusion of the fluid is provided after the last pump stage.

Claim 16

Dependent Claim 36 words

The pump of claim 10, wherein the rotor of a second pump stage is arranged to impart a whirl component in the same direction as the direction of rotation of the rotor of the first stage.

Claim 17

Dependent Claim 42 words

The pump of claim 10, wherein said at least one stage includes two stators, one upstream and one downstream of the rotor, the rotor arranged to induce whirl in one direction and the stators arranged to induce whirl in the opposite direction.

Claim 18

Dependent Claim 20 words

The pump of claim 10, wherein the rotor is in the form of an impeller mounted on a rotatable shaft.

Claim 19

Dependent Claim 22 words

The pump of claim 10, wherein the stator is mounted to the casing which defines the outer wall of the pump stage.

Claim 20

Dependent Claim 28 words

The pump of claim 10, wherein a stator is provided downstream of the rotor and has bull-nosed vanes capable of tolerating a wide range of flow incidence angles.

Claim 21

Dependent Claim 68 words

The pump of claim 10, wherein the stator is configured such that, at or near the design duty flow, the fluid is discharged from the stator with an absolute velocity which has substantially the same axial component as the fluid entering the stator, and has a whirl component of velocity which is substantially the same as the whirl component entering the stator, but in the opposite rotational direction.

Claim 22

Dependent Claim 22 words

The pump of claim 10, wherein the rotor is in the form of a series of impellers mounted on a rotatable shaft.

Claim 23

Dependent Claim 19 words

The pump of claim 10, wherein the stator is formed of a plurality of radially extending blades or vanes.

Claim 24

Dependent Claim 21 words

The pump of claim 10, wherein the stator has bull-nosed vanes capable of tolerating a wide range of flow incidence angles.

Claim 25

Dependent Claim 17 words

The pump of claim 10, wherein the rotor has a fluid flow coefficient of less than 0.4.

Claim 26

Dependent Claim 18 words

The pump of claim 23, wherein the rotor has a fluid flow coefficient of between 0.15 and 0.25.

Claim 27

Independent Claim 108 words

A method of pumping or compressing a fluid utilizing a multistage axial pump or compressor, the method including the steps of: imparting whirl to the fluid in a first rotor; and then imparting whirl to the fluid in the opposite direction in a first stator with little or not diffusion such that, at or near the design duty flow, the fluid is discharged from the stator with an absolute velocity with has substantially the same axial component as the fluid entering the stator, and has a whirl component of velocity which is substantially the same as the whirl component entering the stator, but in the opposite rotational direction.

Claim 28

Independent Claim 108 words

A method of pumping or compressing a fluid utilizing a multistage axial pump or compressor, the method including the steps of: imparting whirl to the fluid in a first rotor; and then imparting whirl to the fluid in the opposite direction in a first stator with little or not diffusion such that, at or near the design duty flow, the fluid is discharged from the stator with an absolute velocity with has substantially the same axial component as the fluid entering the stator, and has a whirl component of velocity which is substantially the same as the whirl component entering the stator, but in the opposite rotational direction.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1999-10-08	2000-04-08	2000-10-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2003-10-08	2004-04-08	2004-10-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2007-10-08	2008-04-08	2008-10-08	$7700.00	Window Closed / Lapsed

Multistage axial flow pumps and compressors

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