Fluid Tight Electric Connector

Abstract

Tight electric connector formed of two connection members having each an insulating plug housed in a casing and projecting beyond the casing end surface, a stud embedded into said plug and projecting beyond the end surface of said plug, and an annular recess between said plug and said casing forming a space for the flow of the plug insulating material, occurring when the two connection members are pressed against each other.

Description

This invention relates to a fluid tight electric connector of a new type providing for the tight connection between two electrical circuits placed in a fluid medium, particularly in a liquid medium which may be electrically conducting.

The electric connectors proposed up to now generally comprise two complementary members coated with or consisting of an elastomer. At the surface of said elastomer are placed electric studs or contact elements. Centering devices or interpenetrating plugs of complementary shapes of the two connection members provide an accurate positioning of the corresponding contact elements of said connection members. By bringing closer to each other the two connection members of the connector, for example by screwing of a threaded ring or of a screw, there is established the electric connection between the contact elements, while a certain flow of the elastomer provide for the simultaneous contact of several studs. It happens that the elastomer flow also ensures a good sealing about each contact element or even of the whole connector. These devices are generally suitable when the connection members are of small size, the two connection members being then easily and with sufficient accuracy, positioned with respect to each other. The assembling of the two connection members is usually made by hand and the pressing forces are relatively small and may reach a maximum of a few kilograms.

In the case where the connection members to be assembled are very heavy and of a large size, e.g. of about one meter, provided with electric contact elements, the plugs or connectors of the above type are no longer satisfactory. In fact, in such a case, the clearances in the mechanical assembling reach values higher than one millimeter and do not permit a sufficiently accurate positioning of the two complementary members of the connector. It is therefore not possible to make use of interpenetrating contactors or of rigorous centering devices for positioning in front of each other the electric contact studs of each connector element. Moreover the pressing force on the connection members being very high, e.g several hundreds of kilograms, results in a flow of the elastomer which is difficult to control and it has been observed that the electric connections were not always properly established.

Repeated experiments have lead to the tentative explanation that the substantially uncontrolled flow of the elastomer was responsible, in connectors of the prior art, for the spacing of the electric contact elements and it is therefore an object of this invention to provide a new tight electric connector having well defined size characteristics so that, during the pressing of the connection members, the flow of a deformable insulating material such as an elastomer performs simultaneously the establishment of the electric connections between the contact elements, a good electrical insulation and a good sealing about each of said contact elements.

It is a main object of the invention to provide a new tight electric connector which may operate even in a liquid conducting medium.

It is another object of the invention to define the shape and size characteristics of an electric connector of the above-mentioned type which may be operated under normal conditions when the connection members to be assembled are of a large size.

It is still another object of the invention to provide an electric connector of the above-defined type which may withstand high pressing forces.

These objects are attained by the tight connector of this invention consisting of at least one pair of connection members each formed of a casing housing a plug of substantially incompressible deformable insulating material comprising a conducting stud projecting outside the plug above the free surface thereof, the electric connection being achieved by mere application on each other of the studs of the connection members in a position of closeness of the latter, by pressing against each other their respective deformable plugs, wherein the free surface of the deformable plug of each connection member protrudes from its housing above the edge thereof and wherein a recess is arranged around the plug in its housing, close to the edge thereof, leaving a space for the flow of said deformable material when the two connection members are pressed against each other, thereby ensuring the sealing and the electric insulation around each conducting stud.

The invention will be better understood from the following description of non-limitative embodiments given by way of examples and illustrated by the accompanying drawings wherein :

FIG. 1 illustrates an example of use of an electric connector according to the present invention,

FIG. 1A diagrammatically shows a distribution of the clearances during the assembling of large sized members

FIG. 2 shows one embodiment of connector according to the invention,

FIGS. 3 to 6 illustrate the operation of assembling the two members of the connector of FIG. 2,

FIG. 7 illustrates a variant of assembling the two members of the connector of FIG. 2,

FIG. 8 shows another embodiment of connector according to the invention, and

FIG. 9 is a variant of the connector of FIG. 8.

FIG. 1, to which we will refer again, shows an example of use of a connector of this invention on a submerged oil well head.

Reference 1 indicates the top block of the oil well head submerged at great depth, for example 200 or 300 meters on which operations are to be performed with the aid of a special device therefor diagrammatically shown with reference 2.

The connection of device 2 to the top of the well head 1 is, for example, carried out in a known manner, by means of a coupling 3 secured on the end of device 2.

This connection must allow the establishment of electric connections diagrammatically shown with reference 4, said electric connections being provided, for example, in order to ensure the continuity of the remote control circuits for actuation devices present on the well head or of telemetering circuits etc. . . .

It is clearly apparent that, due to the large size and consequently the high weight of the members to be assembled on the one hand and to the requirement of performance of the assembling operation through means remotely controlled from a floating installation (not shown in the figure), on the other hand, it is necessary to suffer, between the complementary parts of the connection members, assembling clearances which may be as large as 1 millimeter and sometimes more. Accordingly there is to be observed an inaccurate line up of the members to assemble or a bad parallelism of the contact surfaces, even in some cases both of these drawbacks as diagrammatically shown in FIG. 1A.

FIG. 2 illustrates an embodiment of connector according to this invention. The connector comprises two identical connection members, only one of which is shown in FIG. 2.

This element to which is given the general reference 4, comprises a casing or rigid body 5 of any external shape adapted to the conditions of use of the connector.

Inside the body 5 is a housing 6 wherein is placed a plug 7 made of a deformable insulating material such as elastomer and which projects by a height h above the outer surface of the body 5. A diameter reduction 9 of said plug 7 is provided at its upper part thus forming an annular groove or recess 10 between the plug 7 and the housing 6.

A stud or electrically conducting element 11 is partially driven in the plug 7 and projects by a height e above the plug surface. A flexible conductor 12 for the current supply is connected to stud 11 through any known means.

The size characteristics of said connection member which are necessary for a proper operation are the following:

a. the plug 7 of incompressible elastomer must not be prestressed when placed in position into the bore 6 of body 5 and the clearance between the diameter of the housing or bore 6 and the plug diameter must be from 0 to 0.1 millimeter preferably between 0 and 0.05 mm.

b. the ratio el h must be between 1/2 and 1/4 and /preferably close to 1/3.

c. the volume of the annular groove 10 must be at leaSt equal to the volume of the protruding portion of plug 7.

The selection of the elastomer is not critical, but the best results have been obtained with the use of an incompressible elastomer having a sufficient hardness i.e hardness degree in shore units in the range from 50 to 75, preferably from 60 to 65.

Moreover, as it will be apparent from the description of the operation of a connector according to this invention, the height h of the elastomer above the connector body, is chosen at least equal to one half of the maximum clearance m (FIG. 1A) acceptable between the opposed surfaces of the members to be assembled.

FIGS. 3, 4 and 5 illustrate the operation of the embodiment of the invention shown in FIG. 1.

In FIG. 3 members 4 and 4a of the connector are positioned and fixed respectively in the top block 1 of the well head and in the coupling 3. Of course the bodies 5 and 5a of the connection members might be optionally omitted and the plugs 7 and 7 a directly housed in the respective cavities of the top block 1 of the well head and of coupling 3.

As shown in FIG. 4, when the coupling 3 is brought closer to the top block 1, the end surfaces 13 and 13a of studs 11 and 11a come into contact, thereby establishing the electrical connection. The surfaces 13 and 13a are so designed as to be large enough, in spite of any misalignment of the two connector members resulting from the assembling tolerances, for ensuring a contact zone of a sufficient surface between studs 11 and 11a,giving passage to the electric current without abnormal heating.

The coupling 3 is brought closer and closer to the well head until the end surface 14 thereof comes into contact with the end surface 15 of the top block 1 of the well head, as shown in FIG. 5. The corresponding pressing of the connection members against each other results in the flow of the elastomer of plugs 7 and 7a, which is made easier by the provision of recesses or grooves 10 and 10a. The elastomer thus forms a sealing ring providing, in addition, a good electrical insulation about studs 11 and 11a.

FIG. 6 illustrates the case where, as a result of the accepted tolerances, the two end surfaces of the members to be assembled are not parallel. In such a case , even after pressing of the members against each other, it still remains a slight clearance m which is lower than 2h, h being (FIG. 2) the protrusion of projection height of the elastomer plug above the connector body. Accordingly as shown in FIG. 6, there is still achieved a sufficient flow of the elastomer for ensuring the insulation and sealing about studs 11 and 11a.

As it is apparent from the above description, a connector according to this invention may be used for establishing electrical connections between elements immersed in a liquid medium, even electrically conducting.

FIG. 7 illustrates a preferred embodiment of a connector according to the invention. At least one of the connection members, e.g. 4a in FIG. 7, is rigidly locked onto coupling 3 by means of any known device such as an elastic stop ring of the circlip type 16, whereas the body 5 of the other member 4 may slide into the bore 17 of top block 1, the protruding portion of member 4 with respect to block 1 being limited by a circlip 19, co-operating with a shoulder 20 of body 5. An elastic device 18, shown in the drawing as a spring, is interposed between the body 5 and the bottom of bore 17.

This elastic device is adapted to exert on the body 5 of element 4 a force substantially equal to the pressing force exerted for assembling members 3 and 4. Any clearance m between members 1 and 3 to be assembled is completely, balanced by the only sliding of member 4, if smaller than the sum of the protrusion height C.sub.1 of body 5a of member 4a with respect to coupling 3 (which is non-existent in the embodiment of FIG. 7) and of the protrusion height C.sub.2 of body 5 of member 4 with respect to top block 1 when the elastic device is not compressed. The operation of the connector will always be convenient as long as clearance m is lower or at most equal to C.sub.1 + C.sub.2 +2h,h being the protrusion height of elastomer plugs 7 and 7a respectively with respect to bodies 5 and 5a.

In practice, the selected height C.sub.1 is about 1 millimeter and the height h about 1 to 1.5 mm for members to be assembled having sizes of the order of one meter, on which are exerted pressing forces in the range of from about one hundred of kilograms to about one ton, the maximum acceptable clearance between surfaces 14 and 15 of members 1 and 3 being thus of about 4 mm, which limit is in fact never reached.

FIG. 8 shows another preferred embodiment of connector according to this invention.

It has been observed in practice that the flow of the elastomer takes a very prominent part. Besides, it has been established, by experience, that, when using studs of a thickness e, sticken on the surface of the plug, the obtained results are not satisfactory. Due to the high pressing forces a rapid deterioration of the elastomer plug, e.g by tear, has been observed. When using cylindrical studs partially driven in the elastomer plug such as those shown in FIG. 2, the flow of the elastomer tends to separate the studs which have to come into contact when pressing on the connection members. This phenomenon is due partly to the flow of the elastomer which under the high pressing forces applied thereon, comes to a position where it is interposed between the contact surfaces of the studs, and partly to the cylindrical shape of the studs which does not provide for an efficient anchoring thereof in the elastomer plugs, thus making possible the flow of the whole mass of elastomer surrounding the cylindrical surface of the studs.

By experience it has been observed that the stud shape illustrated in FIG. 8, comprising a conical portion with an increasing diameter towards the inside of the plug, gives the best results.

In this embodiment the plug is manufactured by direct vulcanization on the stud and the groove 10 is obtained by machining a chamfered edge on body 5. As shown in said figure the elastic device 18 may consist of a pile of so-called "Belleville" spring washers.

FIG. 9 shows an alternative embodiment of FIG. 8 with the surfaces of studs 11 and 11a establishing the electrical contact. The stud 11 has a plane contact surface and the stud 11a has a conical contact surface which can be impressed in stud 11. The stud 11 may for example be made of lead and stud 11a of an aluminum alloy well known in the art under reference AG.sub.5.

It will be understood that, while there has been given herein certain specific examples of the practice of this invention, it is not intended thereby to have this invention limited to or circumscribed by the specific details of materials, sizes, proportions or conditions herein specified in view of the fact that the invention may be modified according to individual preference or conditions without necessarily departing from the spirit and scope thereof, and consequently such modifications are properly, equitably and intended to be within the full range of equivalence of the appended claims.

Claims

What we claim as this invention is:

1. A tight electric connector comprising two connection elements, each having at least one conducting stud embedded in a plug of deformable and substantially incompressible insulating material, the conducting stud protruding from the plug free surface, the electrical connection resulting from the contacting of the conducting studs at a close position of said connection elements, each stud being provided with an individual housing for the plug in which said stud is embedded, the free surface of the deformable plug protruding from its housing above the edge thereof and having a recess arranged at the periphery of the plug close to and extending below the edge of the housing to provide for the flow of said deformable material both into the recess and about the stud as a result of the pressing of said two connection elements against each other such that a seal and electrical insulation is provided about each conducting stud.

2. Tight electric connector according to claim 1, the plug wherein is made of substantially incompressible elastomer whose hardness degree, expressed in shore units, is between 50 and 75.

3. Tight electric connector according to claim 1 wherein the plug is made of substantially incompressible elastomer whose hardness degree, expressed in shore units, is between 60 and 65.

4. Tight electric connector according to claim 1, wherein said recess is formed by a diameter reduction of said plug in the vicinity of said housing edge.

5. Tight electric connector according to claim 1, wherein said recess is formed in said housing by machining the edge of said housing about the periphery of said plug.

6. Tight electric connector according to claim 1, wherein said stud is cylindrical.

7. Tight electric connector according to claim 1, wherein the contact surfaces of the studs of each of said connection elements are plane surfaces and the studs are made conducting material.

8. Tight electric connector according to claim 1 for establishing electrical connections between two connecting parts of large size, each connection element of said connector being carried on one of the connecting parts to be assembled, wherein an elastic device is interposed between at least one of the connection elements and the connecting part carrying said element for biasing the connection element toward the other connecting part to be assembled.

9. Tight electric connector according to claim 1, wherein said plug and said stud are connected by vulcanization.

10. Tight electric connector according to claim 1 wherein the ratio of the protrusion height of the conducting stud above the plug to the protrusion height of the plug above the housing of the conducting stud has a value between 0.25 and 0.5.

11. Tight electric connector according to claim 10 wherein said ratio has a value close to 0.33.

12. Tight electric connector according to claim 1 wherein the assembling clearance between the plug and its housing in said casing is between 0 and 0.1 mm.

13. Tight electric connector according to claim 12 wherein said clearance is between 0 and 0.05 mm.

14. A tight electric connector formed of at least one pair of connector members each comprising a casing wherein is housed a plug of deformable insulating material, substantially incompressible, comprising a conducting stud protruding from the plug free surface, the stud having a conical shape with an increasing diameter towards the inside of the plug and being extended by a cylindrical portion of a diameter lower than the greater diameter of the conical portion, the electrical connection resulting from the mere application of the connection member studs on each other in a position of closeness of said members, by pressing said deformable plugs against each other, wherein the free surface of the deformable plug of each connection member protrudes from its housing above the edge thereof and wherein a recess is arranged about the plug in its housing, close to the edge thereof, in order to leave a space for the flow of said deformable material which results from the pressing of said two members against each other, thereby ensuring the sealing and electrical insulation about each conducting stud.

15. A tight electric connector formed of at least one pair of connector members each comprising a casing wherein is housed a plug of deformable insulating material, substantially incompressible, comprising a conducting stud protruding from the plug free surface, the electrical connection resulting from the mere application of the connection member studs on each other in a position of closeness of said members, by pressing said deformable plugs against each other, the contact surface of the stud of one of said connection members is conical and the contact surface of the stud of the other is flat, wherein the free surface of the deformable plug of each connection member protrudes from its housing above the edge thereof and wherein a recess is arranged about the plug in its housing, close to the edge thereof, in order to leave a space for the flow of said deformable material which results from the pressing of said two members against each other, thereby ensuring the sealing and electrical insulation about each conducting stud.

16. A tight electric connector according to claim 15 wherein said stud having a conical contact surface is made of a conducting material of a greater hardness than that of which is made the stud having a plane surface.

17. Tight electric connector formed of two connection members having each an insulating plug of deformable material housed in an individual casing and projecting beyond the casing end surface, a stud embedded into said plug and projecting beyond the end surface of said plug, and an annular recess provided in at least one of said plug and said casing proximate to and extending below the casing end surface forming a space for the flow of the plug insulating material, occurring when the two connection members are pressed against each other.