Pin for a subsea connector

Abstract

A pin for a subsea connector having an electrical conductor, an insulating sleeve around the conductor and a conductive layer provided on a portion of the outer surface of the insulating sleeve. The insulating sleeve has a recess that extends in an axial direction over a portion of the insulating sleeve. The conductive layer is provided in the recess.

Claims

1. A pin for a subsea connector, comprising: an electrical conductor, an insulating sleeve around the electrical conductor, wherein the insulating sleeve has an outer surface, a conductive layer provided on a portion of the outer surface of the insulating sleeve, wherein the pin has a front end and a rear end and extends in an axial direction between the front end and the rear end, wherein the insulating sleeve has a recess that extends in the axial direction over the portion of the insulating sleeve, wherein the conductive layer is provided in the recess, wherein the outer surface of the insulating sleeve and an outer surface of the conductive layer comprise a same diameter.

2. The pin according to claim 1, wherein the conductive layer fills the recess.

3. The pin according to claim 1, wherein the recess has a forward end, and wherein the conductive layer is a ground layer that is configured to be earthed during operation of the pin, wherein the forward end is shaped so as to control an electric field profile of the pin during operation.

4. The pin according to claim 1, wherein at a forward end of the recess, a depth of the recess is gradually reduced.

5. The pin according to claim 4, wherein the forward end of the recess is rounded with a radius that is larger than the depth of the recess.

6. The pin according to claim 5, wherein a radius end point is located outside and above the recess.

7. The pin according to claim 1, wherein the pin is a connector pin of a first connector part of a subsea connector; wherein the pin has a sealed portion that is sealed inside a second connector part of the subsea connector when the subsea connector is in a mated state; and wherein the recess and the conductive layer extend in the axial direction into the sealed portion.

8. A connector part of a subsea wet-mateable connector, wherein the connector part is configured to engage a complementary second connector part of the subsea wet-mateable connector, wherein the connector part comprises a support; a pin according to claim 1, the pin projecting forward from the support, wherein said recess and said conductive layer are provided adjacent to and forward of the support.

9. A method of manufacturing a pin of a subsea connector, comprising: providing an electrical conductor and an insulating sleeve around the electrical conductor, wherein the insulating sleeve has an outer surface, wherein the electrical conductor and the insulating sleeve comprise part of a pin that has a front end and a rear end and extends in an axial direction between the front end and the rear end, providing a recess in the outer surface of the insulating sleeve, wherein the recess extends in the axial direction over a portion of the insulating sleeve, providing a conductive layer in the recess, and wherein the outer surface of the insulating sleeve and an outer surface of the conductive layer are flush with each other.

10. The method according to claim 9, wherein providing the recess comprises machining the recess into the insulating sleeve.

11. The method according to claim 10, wherein machining the recess into the insulating sleeve is performed so as to provide a forward end of the recess with a gradually reducing depth.

12. The method according to claim 9, wherein the conductive layer is provided by thermal spraying.

13. The method according to claim 9, wherein after providing the conductive layer, the method further comprises: machining the pin to a same outer diameter over an axial portion of the pin that comprises at least a forward portion of the recess and of the conductive layer.

14. The method of claim 13, wherein the axial portion of the pin comprises a whole axial portion in which the recess and the conductive layer are provided.

15. The pin according to claim 4, wherein the forward end of the recess is rounded.

16. The method according to claim 11, wherein the forward end of the recess is rounded.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The forgoing and other features and advantages of the invention will become further apparent from the following detailed description read in conjunction with the accompanying drawings. In the drawings, like reference numerals refer to like elements.

(2) FIG. 1 is a schematic drawing showing a sectional view of a component to which a layer is applied.

(3) FIG. 2 is a schematic drawing showing a perspective view of a pin according to an embodiment.

(4) FIG. 3 is a schematic drawing showing a sectional view of an insulating sleeve with a recess according to an embodiment.

(5) FIG. 4 is a schematic drawing showing a perspective view of a pin according to an embodiment.

(6) FIG. 5 is a schematic drawing showing a sectional view of an insulating sleeve including a recess and a conductive layer according to an embodiment.

(7) FIG. 6 is a schematic drawing showing a sectional view of an insulating sleeve including a recess and a conductive layer according to an embodiment.

(8) FIG. 7 is a schematic drawing showing a sectional side view of a subsea wet-mateable connector including a pin according to an embodiment of the invention.

(9) FIG. 8 is a flow diagram illustrating an embodiment of a method according to the invention.

DETAILED DESCRIPTION

(10) In the following, embodiments illustrated in the accompanying drawings are described in more detail. It is to be understood that the following description of the embodiments is given only for the purpose of illustration is not to be taken in a limiting sense. It should be noted that the drawings are to be regarded as being schematic representations only, and elements in the drawings are not necessarily to scale with each other. Rather, the representation of the various elements is chosen such that their function and general purpose become apparent to a person skilled in the art.

(11) FIG. 1 schematically illustrates a coating according to the prior art. A piece of material 90 is provided with a coating 91. As can be seen, the coating 91 forms a step on the surface of the substrate 90. Accordingly, in applications where a seal slides over the surface of the substrate 90, such step can hinder the travel of the seal on the surface of the substrate 90. Furthermore, it is clear that such seal must be capable of accommodating different diameters, it may need to be capable of sealing against the surface of the substrate 90 and against the coating 91. This may result in a reduced sealing efficiency and in a more complex configuration of the seal. If the thickness of the coating 91 exceeds a certain size, it might not even be possible to provide sufficient sealing with a seal that needs to slide over the step. Furthermore, the shape of the forward end of the coating 91 is generally defined by the masking and cannot be changed. Accordingly, relatively high electrical stresses due to electric field gradients may occur at the forward end of such coating.

(12) FIG. 2 illustrates a pin 10 according to an embodiment of the invention. The pin 10 includes a conductor 12 that is surrounded by the insulating sleeve 11. The pin 10 extends along an axial direction from a front end 13 to a rear end 14. The insulating sleeve 11 may only cover a part of the conductor 12, the conductor 12 may for example protrude from a forward end of the insulating sleeve 11 for being connected to a forward contact portion (e.g., the contact portion 21 in FIG. 7), and/or it may protrude from a reward end of the insulating sleeve 11 for being connected to a further conductor, for example another pin or the conductor of a cable, for example by crimping. It should further be clear, that the insulating sleeve 11 is only illustrated schematically in FIG. 2 to highlight features of the present embodiment, and that the shape of the insulating sleeve 11 may be different in different applications, as for example shown in FIG. 7.

(13) In the insulating sleeve 11, a recess 15 is provided. The recess 15 has a forward end 17 and a rearward end 18. It should be clear that in some configurations, there may not be provided a rearward end 18 and the recess 15 may extend all the way to the rearward end of the insulating sleeve 11.

(14) The pin 10 may for example be the pin of a subsea wet-mateable electrical connector. In operation, the voltage, in particular an AC-voltage, may be applied to the electrical conductor 12. The insulating sleeve 11 provides electrical insulation for the conductor 12. In order to provide good electrical insulation, the insulating sleeve 11 has a thickness d, which is the difference between the outer diameter and the inner diameter of the insulating sleeve 11.

(15) The insulating sleeve 11 may be a pre-manufactured component having a through bore into which the conductor 12 is inserted. In other embodiments, the insulating sleeve 11 may be a component that is molded around the conductor 12. Other configurations are certainly conceivable.

(16) As can be seen in FIG. 2, the depth of the recess is only a fraction of the thickness of the insulating sleeve 11. This is illustrated in more detail in FIG. 3 which shows a cross section through a portion of the insulating sleeve 11 which includes the forward end 17 of the recess 15. The recess has a depth r. The depth r is significantly smaller than the thickness d, it may for example the smaller than 5%, or even smaller than 1% of the thickness d.

(17) As an example, the thickness d may be between about 5 mm and about 50 mm, whereas the depth r may be between about 0.001 mm and about 1 mm. Advantageously, the depth r is between about 100 m and about 800 m.

(18) As can be seen in FIG. 3, the forward end 17 of the recess 15 can be provided with a desired shape. In the example of FIG. 3, the forward end is rounded to provide a smooth transition from the recess 15 to the non-recessed surface of the insulating sleeve 11.

(19) The pin 10 is furthermore provided with a conductive layer 16 that is illustrated in FIG. 4. Note that in FIG. 4, the conductor 12 is not shown but may certainly be present. The conductive layer 16 is provided in the recess 15. Most of the recess 15 is covered with the conductive layer 16. Advantageously, the conductive layer 16 completely fills the recess 15. As illustrated in FIGS. 5 and 6, the conductive layer 16 is advantageously flush with the outer surface 19 of the insulating sleeve 11 in a portion forward of the forward end 17. Similarly, the conductive layer 16 may also be flush with the outer surface 19 of the insulating sleeve 11 at the rear ward end 18 of the recess 15. In other embodiments, the conductive layer 16 may also extend over the outer surface 19 of the insulating sleeve 11 at the rear ward end 18 of the recess 15, for example for providing electrical contacting to earth/ground the conductive layer 16, although such contacting can certainly also occur if the conductive layer 16 is flush at the rearward end 18.

(20) The outer surface of the insulating sleeve 11 is designated with reference numeral 19 in FIGS. 3, 5 and 6, it defines the outer perimeter of the pin forward of the recess 15 and then extends underneath the conductive layer 16.

(21) As can be seen in FIGS. 5 and 6, by providing the conductive layer 16 in the recess 15, the outer surface of the pin 10 is in a forward portion of the pin defined by the outer surface 19 of the insulating sleeve 11 and is continued by the conductive layer 16, so that there is no step. Accordingly, a seal can slide along the outer surface 19 and onto the conductive layer 16 without the need to adapt to different diameters of the pin 10. The configuration of the seal can thus be simplified. Furthermore, there is no or only little abrasion to the conductive layer 16 upon repeated mating cycles, i.e. upon a repeated sliding of the seal over the conductive layer 16. Furthermore, a degradation of the seal by the repeated sliding over a step can be prevented in such configurations. In particular, with the described embodiments, it becomes possible to provide the pin 10 with an almost constant outer diameter in the portion over which the seal slides. Reliability and robustness of a connector employing such pin may thus be improved.

(22) As outlined above, by providing the conductive layer in the recess 15, it becomes possible to adapt the shape of the conductive layer 16 at the forward end 17 to the desired application. The geometry of this so called run-out of the conductive layer 16 can be adjusted to improve the mechanical performance and the electrical performance of the conductive layer 16. With respect to mechanical performance, the geometry may be adapted so as to ensure good compatibility with respect to thermal expansion. As an example, it may be ensured that the mechanical hoop stress induced by thermal expansion does not exceed the tensile strength of the conductive layer 16. Good mechanical performance can for example be obtained with a geometry of the run-out of the conductive layer 16 as illustrated in FIG. 6.

(23) With respect to electrical performance, the conductive layer 16 is generally earthed to provide shielding of the seal in the connected state of the subsea connector against the electromagnetic field generated by the electrical power that is transported by means of the conductor 12. Since the conductive layer 16 is earthed, the field is confined to within the electrical insulating sleeve 11. At the position at which the conductive layer 16 ends, the field will leave the insulation. By adjusting the geometry of the run-out of the conductive layer 16, a graduated exit of the field through the insulation may be achieved. This may for example be achieved by providing a rounded forward end 17 of the recess 15 and thus of the conductive layer 16. Such configuration avoids high electric field gradients and thus high electrical stresses.

(24) Advantageously, the forward end of the recess 15 is shaped as illustrated in FIG. 5. The recess 15 has a rounded forward end 17. The angle at the run-out of the conductive layer 16 between the outer surface of the conductive layer 16 and the surface of the recess 15 is advantageously within a range of about 25 degrees to about 90 degrees, advantageously it is smaller than 90. As an example, it may be about 60 as illustrated in FIG. 5.

(25) By such configurations, wear resistance of the conductive layer 16 can be improved, and good mechanical properties of the conductive layer 16 over a wide thermal range can be achieved. Furthermore, by the design of the forward end 17 of the recess 15, the control of the electromagnetic field, in particular high voltage field generated by electrical power transported through the conductor 12, can be controlled.

(26) FIG. 7 illustrates a subsea wet-mateable connector 100 having a first connector part 101 and a second connector 102 according to an embodiment of the invention. The first connector part 101 comprises a pin 10, and the pin 10 can have any of the configurations described above and illustrated in FIGS. 2 to 6. The first connector part 101 has a housing 105 with a support 110, in which the pin 10 is supported. It should be noted that the basic connector components are shown only very schematically, and that the subsea wet-mateable connector 100 can be configured in accordance with any previously known wet-mateable connector.

(27) The conductor 12 extends through the conductive sleeve 11 of the pin 10 and is in electrical contact with the forward contact portion 21 of the pin 10. During the mating of the first and the second connector parts 101, 102, the pin 10 enters an opening in the second connector part 102. Upon completion of the mating procedure, the contact portion 21 of the pin 10 is in electrical contact with the socket contact 22 in the second connector part 102. Generally, a shuttle pin or a shuttle piston (not shown) will be provided inside the opening of the second connector part 102 to prevent exposure of the internal components of the second connector part 102 to the subsea environment.

(28) Upon the pin 10 entering the opening in the second connector part 102, the seal 30 will slide over the outer surface of the pin 10 in sealing engagement therewith. Ingress of seawater into the second connector part 102 during the mating procedure and in the mated state will thus be prevented. Accordingly, during the mating, the seal 30 slides along the outer surface of pin 10 and eventually slides over the conductive layer 16 that is provided in the recess 15. As outlined above, since the outer surface of insulating sleeve 11 and the outer surface of the conductive layer 16 are substantially flush, i.e. there is no step, the above outlined advantages can be achieved.

(29) In the fully mated state, the seal 30 is generally in contact with the outer surface of pin 10 in the region where the conductive layer 16 is provided. Accordingly, the seal 30 is effectively screened from the electrical stresses induced by the electrical field generated by the voltage applied to the electrical conductor 12. In some embodiments, a portion of the pin adjacent to the support 110 may be exposed to seawater in the mated state. The conductive layer 16 may in such configuration furthermore provide protection against the diffusion and permeation of seawater into the insulating sleeve 11. In other configurations, a further protection may be provided for the pin 10, such as a sliding carriage, so that the rear portion of the pin 10 is located within an oil filled volume or the like and is protected from surrounding seawater.

(30) At the rear portion of the pin 10, the pin 10 may for example be sealed towards the support 110 by means of O-ring seals 115. The conductive layer 16 may be in electrical contact with the support 110 for providing a connection to ground, or a dedicated contact may be provided for grounding the conductive layer 16.

(31) The second connector part 102 may comprise further seals that slide on the surface of the pin 10 during mating. These may similarly benefit from the advantages outlined above with respect to the embodiments described herein.

(32) The recess 15 and the conductive layer 16 may extend only over a portion of the insulating sleeve 10. In particular, a predetermined spacing between the forward contact portion 21 and the grounded conductive layer 16 is maintained. Generally, the conductive layer 16 extends from a position adjacent to the support 110 to a position that is located forward of the support 110 and that is located on a sealed portion of the pin that is sealed inside the second connector part 102 by means of the seal 30 when the connector 100 is in the mated state. Good electrical screening can thus be ensured.

(33) FIG. 8 shows a flow diagram of a method of manufacturing a pin according to an embodiment of the invention. The method may be carried out so as to obtain the pin in any of the above outlined configurations. In a first step 81, the insolating sleeve 11 is provided, either on a conductor, for example molded around a conductor, or as a separate piece. In step 82, the recess 15 is machined into the insulating sleeve 11, as shown in FIG. 2. In step 83, a layer of conductive material is provided in the recess 15 of the insulating sleeve 11. The conductive material may be applied to the insulating sleeve by methods such as thermal spraying. It is noted that with the present method, it is not necessary to provide a very precise masking of the area that is to be covered by the conductive material. Masking of the area to be provided with conductive material is thus simplified. The layer of conductive material that is applied to the insulating sleeve 11 has a thickness sufficient to completely fill the recess 15.

(34) In the next step 84, the insulating sleeve including the portion to which the layer of conductive material was applied is machined to a predetermined outer diameter. As an example, the whole insolating sleeve may be machined to a predetermined outer diameter, so that the outer diameter is constant over the whole axial extension of the insulating sleeve. In other embodiments, only a forward portion of the insulating sleeve including the forward end of the conductive layer may be machined to the desired outer diameter.

(35) By such manufacturing method and by machining the insolating sleeve with the applied layer of conductive material to the desired outer diameter, a superior quality of the resulting conductive layer 16 can be obtained, thus reducing defect initiators. Furthermore, such method provides a high degree of control over uniformity, thickness and surface finish of both the insolating sleeve and the resulting conductive layer 16. Even further, by the machining step, it may be ensured that the conductive layer is flush with the remaining exposed outer surface of the insulating sleeve, in particular that no steps occur. Also, post machining operations are simplified due to the constant outer diameter of the insulating sleeve including the conductive layer 16. As can be seen, embodiments of the method provide an improved and simplified manufacturing of the pin.

(36) While specific embodiments are disclosed herein, various changes and modifications can be made without departing from the scope of the invention. The present embodiments are to be considered in all respects as illustrative and non-restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced wherein.