Subsea sensor assemblies

Patent metadata

Field	Value
Publication number	US-9671250-B2
Application number	US-201414258880-A
Country	US
Kind code	B2
Filing date	Apr 22, 2014
Priority date	Apr 22, 2014
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

Sensor assemblies, electrical penetrator assemblies and associated methods are provided for monitoring operational characteristics of subsea rotating devices such as subsea motors and pumps. Pressure-compensated proximity sensors configured to withstand subsea pressures are disposed adjacent a subsea rotating shaft for directly monitoring a position of the rotating shaft during dynamic operation thereof. A sensor tip assembly includes a sensor cap and a sensing element therein configured to produce a signal indicative of a distance between the sensor cap and the rotating shaft. A substantially incompressible fluid is disposed within a fluid reservoir within a sensor housing, and fluidly communicates with the sensor cap such that at least a portion of an internal pressure within the sensor housing is applied to interior portions of the sensor cap. The sensor housing is configured such that the internal pressure increases in response to an increase in an external pressure of the sensor housing.

First claim

That claimed is:

1. A pressure-compensated proximity sensor assembly, comprising: a proximity sensor tip assembly including a proximity sensor cap at an end thereof and a sensing element disposed at least partially within the proximity sensor cap, the sensing element configured to produce a signal indicative of a distance between a reference point on the proximity sensor tip assembly and a reference point on a target proximate the proximity sensor cap;
and a sensor housing connected to the proximity sensor cap, the sensor housing defining a fluid reservoir containing an incompressible fluid therein, the fluid reservoir in fluid communication with interior portions the proximity sensor cap such that at least a portion of an internal pressure on the incompressible fluid within the fluid reservoir is applied to the interior portions of the proximity sensor cap; and wherein the sensor housing is configured such that the internal pressure on the sensor housing and the incompressible fluid contained therein increases in response to an increase in an external pressure on the sensor housing.

2. The pressure-compensated proximity sensor assembly according to claim 1 , wherein the sensor housing includes a pliable membrane operable to flex inward toward the incompressible fluid contained within the fluid reservoir in response to the increase in the external pressure to apply at least a portion of the external pressure to the incompressible fluid.

3. The pressure-compensated proximity sensor assembly according to claim 2 , wherein the pliable membrane exhibits a greater pliability than exterior surfaces of the proximity sensor cap.

4. The pressure-compensated proximity sensor assembly according to claim 2 , wherein the pliable membrane is at least one of the following: a mechanically thinned portion of a wall of the sensor housing; and a flexible tubing member forming a portion of the wall of the sensor housing.

5. The pressure-compensated proximity sensor assembly according to claim 1 , wherein the fluid reservoir is in fluid communication with the interior portions of the proximity sensor cap by a fluid channel extending between the sensor housing and the proximity sensor cap such that an increase in the pressure applied to the incompressible fluid within the fluid reservoir induces the incompressible fluid to apply an increased pressure to the interior portions of the proximity sensor cap.

6. The pressure-compensated proximity sensor assembly according to claim 1 , wherein the sensor housing includes an extendable section operable to selectively lengthen and shorten the sensor housing to thereby accommodate for range of adjust ability in a gap between the proximity sensor cap and the target.

7. The pressure-compensated proximity sensor assembly according to claim 6 , wherein the extendable section comprises a bellows including a plurality of folds.

8. The pressure-compensated proximity sensor assembly according to claim 1 , wherein the incompressible fluid fills the sensor housing such that the internal pressure within the sensor housing is greater than the external pressure when the proximity sensor assembly is disposed in a generally one-atmosphere environment.

9. The pressure-compensated proximity sensor assembly according to claim 1 , further comprising a signal transmission medium operatively coupled to the sensing element disposed within the proximity sensor cap and extending through the sensor housing to transmit the signal indicative of the distance between the reference point on the proximity sensor tip assembly and the reference point on a target through the sensor housing to thereby measure a position of the target relative to a preselected reference position.

10. The pressure-compensated proximity sensor assembly according to claim 9 , wherein the signal transmission medium is an electrical conductor exhibiting a length sufficient to permit the electrical conductor to follow a serpentine path through the sensor housing along which the electrical conductor is spaced from a wall of the sensor housing such that said medium is not in contact with said wall of said housing.

11. The pressure-compensated proximity sensor assembly according to claim 9 , wherein the signal transmission medium is an electrical conductor and wherein the proximity sensor cap includes an eddy current coil disposed therein, wherein the eddy current coil is electrically coupled to the electrical conductor.

12. The pressure-compensated proximity sensor assembly according to claim 1 , further comprising a supplemental sensor disposed within the sensor housing and submerged within the incompressible fluid, wherein the supplemental sensor comprises at least one of the following: an acoustic sensor; a pressure sensor; temperature sensor; a gyroscope; an accelerometer; a digital compass; a hydrophone; and a microphone.

13. The pressure-compensated proximity sensor assembly according to claim 12 , wherein the supplemental sensor comprises at least one of the following: a piezoelectric sensor; a capacitive sensor and a MEMS sensor.

14. The pressure-compensated proximity sensor assembly according to claim 1 , wherein at least a portion of the sensor housing is flexible to permit the sensor housing to curve along a serpentine pathway.

Assignees

• Gen Electric

Inventors

• Campbell Lam Arthur
• Lu Dan Tho
• Haugen Svein Arild
• Abrahamsen Jens

Classifications

• E21B47/008

  Monitoring of down-hole pump systems, e.g. for the detection of "pumped-off" conditions · CPC title

• E21B47/001

  for underwater installation · CPC title

• H02K11/21

  Devices for sensing speed or position, or actuated thereby (specially adapted for machines having non-mechanical commutating devices H02K29/06, H02K29/14) · CPC title

• E21B43/01

  specially adapted for obtaining from underwater installations · CPC title

• G01B7/14 Primary

  for measuring distance or clearance between spaced objects or spaced apertures (G01B7/30 takes precedence) · CPC title