JPS5855721B2 - Termination methods for electrical cables and the grounds used therein - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for terminating electrical cables and conduits containing electrical conductors and to glands for this purpose, and more particularly (but not necessarily exclusively) to machines of the type relating to British Standard 6121. This invention relates to types of cable terminations that cannot be adequately sealed by using standard cable glands.

Conventional cable termination will be explained with reference to FIG. 11.

In the figure, there is a sealing washer 44 on the outside of the exposed inner sheath 4 of the cable, and further on the outside there is a gland member 43, further on the outside of which a tightening nut 45 is screwed.

This ground member 43 is threadedly connected to one end of a cylindrical member 40, a plug 41 is provided in the center of this cylindrical member 40, and the other end is closed with a lid disc 42. ing.

Note that the conductor 5 from which the inner coating 4 has been removed extends inside the cylindrical member 40 and further penetrates the lid disk 42.

The end of this cylindrical member 40 on the side where the lid disk 42 is located is fitted into the gland cylinder 11, and is tightly tightened from the outside with a tightening nut 46 via a sealing member 47.

An electrical device (not shown) is located on the left side of the figure, and this ground cylinder is connected to the electrical device (not shown).

A compound chamber is formed by the lid disk 42, the cylindrical member 40, the gland member 43, etc., and the plug 41 is removed and a liquid insulator 48 is temporarily poured into this compound chamber and hardened. A disadvantage of the bottom end of the type described above is that the compound chamber occupies a significant amount of space in addition to the space required for the gland.

Traditionally, if the mechanical cable gland does not have an adequate seal, the cable is bottom-ended in a compounding chamber, where the cable conductor connects to the electrical equipment to be connected. However, it is located in a remote location.

This arrangement, in which a compound chamber is provided between the main body of the electrical equipment to which the cable is connected and the gland, occupies considerably more space than the bottom end of the gland type, and in many cases the cable is not sealed. The disadvantage is that it cannot be removed from electrical equipment without destroying it.

This has the disadvantage that the seal at the end of the cable is destroyed if the parts need to be reassembled or screwed in order to restore the termination to service.

According to one aspect of the invention, an electrical cable or conduit is bottomed as follows.

(1) preparing the end of an electrical cable or conduit with individual conductors protruding forward from the end of a protective layer surrounding the cable or from the end of the conduit; (2) preparing the end of an electrical cable or conduit so that the cable or attached to a first gland member having a recess extending through the forward facing surface surrounding the passageway passing through with the end of the conduit; (3) fully filling the recess in the first gland member and connecting the cable or (4) loading a quantity of curable insulating compound in a pasty or viscous state to adhere to the conductors therein; Assemble a second gland member having a recess on the surface facing the first gland member with the first gland member. Applying pressure to the insulating compound by drawing the members together by means of a pulling means and bringing the recesses of the first and second gland members closer together; (6) the gland having the end of the cable or the end of the conduit is attached to the electrical equipment; and this mechanical connection to the electrical equipment is effected by mechanical engagement of an opening in a case of the electrical equipment or an intermediate member attached to the case with at least one said ground member; and ( 7) The conductor of the cable or the conductor contained within the conduit is electrically connected to the electrical equipment within this case.

The invention further provides a first gland member having a recess in the front surface surrounding a passageway for the cable or conduit; means for attaching the cable or conduit to the first gland member; and removable engagement with the first gland member at the rear end. a second ground member having a recess on the rear surface; and first and second
Includes a cable or conduit gland with pulling means for drawing the gland members together.

When the method of the invention is used to terminate a wire armored cable, the cable end is preferably attached to the ground by attaching the armored wire to the first gland member.

The first and second gland members may be drawn together in a variety of ways.

Therefore, both members can be directly screwed together and brought together without requiring the intervention of another member.

Another way in which the parts can be drawn together is by an additional gland member threaded into one of the parts and attached to the other part.

In another form of the invention, two additional gland members are used to draw the first and second gland members together, one attached to each of the first and second gland members, and The two additional members are drawn together by a direct threaded engagement between them or by a draw bolt or equivalent, this latter device comprising:
It is similar to what is traditionally practiced in continental Europe.

When using two separate gland members that are directly screwed together, these usually form a gland tube (which is connected to the first gland member) and a gland barrel (which is connected to the second gland member).

In order to facilitate the creation of pressure within the pasty or viscous compound, the recess of the first gland member preferably has a frusto-conical bottom; and for the same purpose, the second gland member has a frusto-conical bottom. Preferably, it has two parallel ends joined by a sloped portion.

The cable or conduit is attached to the first gland member by a standard gland (i.e. a non-flameproof gland), and the invention includes an adapter that attaches to such a gland to form a gland of the type described above.

Preferably, the second gland member projects further forward than any other gland member so that its presence can be confirmed by visual inspection, and similarly, the amount of insulating compound used is Preferably, it is provided sufficiently to protrude at the front end.

The present invention can also be used in terminating mineral insulated cables; in the case of such cables having a lead sheath, the first
It is preferred to use a composite seal according to the applicant's pending UK patent application no. 346297.

Other features of the invention will become apparent from the accompanying drawings and the following description.

To make the termination shown in Figure 1, the cable fenestration end is cut back in the conventional manner, and the outer sheath 2 is cut open to remove the appropriate lengths of sheath wire 3, interior (or inner sheath) 4, and insulation. The conductor 5 is exposed.

A gland tube 6 carrying a conventional outer seal assembly 7 is screwed onto the prepared cable end from outside with an outer retaining ring 8 as attachment means.

The armored wire is spread out to the position shown, and the first gland member 9 is inserted with its armored cone 10 under the armored wire, and these are gripped by temporarily screwing the gland body 11 into the cylinder. .

The gland tube is then removed and a suitable amount of low-temperature setting resin insulation "compound" 12 is applied, such as by hand, to completely fill the recess with the frusto-conical bottom 13 on the front face of the first gland member 9. , and to be able to endure to a reasonable degree.
Pushed into the recess.

While the curing compound is still pasty or viscous, the second gland member 14 is placed over the conductor 5 of the cable and inserted into the first gland member.

This second gland member has parallel end portions, the front end 15 having a smaller diameter than the rear end 16, and both end portions being joined by a frusto-conical intermediate portion 17.

When the gland body 11 is again screwed into the gland tube 6, the intermediate portion 11 engages with the correspondingly inclined shoulder 18 and presses the first and second gland members together, thereby causing the compound to be injected into the compound. Pressure is generated and these parts are centered to form a flame gap 19 between them using suitable means as described below.

Referring now to flame gaps and flame-retardant sealing rings discussed below, flame-retardant electrical equipment is used in coal mines, petroleum locations, chemical plants, and other locations where there is a risk of encountering an explosive atmosphere. be.

Such flame-retardant equipment is designed with the assumption that the risk of sparks or other ignition sources cannot be completely eliminated inside the equipment, and that entry of ambient atmosphere into the equipment is also avoided. It is designed with the assumption that it cannot occur.

Therefore, it is possible that a small gas explosion may occur inside this equipment, and the design is designed to withstand such an explosion without damaging the housing and without risk of igniting an explosive atmosphere outside the enclosure. has been done.

The purpose of this device is to prevent the ignition of external explosive atmospheres.
This is achieved by making it completely airtight up to the peak explosion pressure, which is what this device is designed for.

However, in many cases such a degree of sealing is impractical or undesirable (depending solely on the nature of the explosive atmosphere encountered and the volume of the gas space inside the enclosure) and British Standards As an alternative to be included, the provision of a passageway between the inside and outside of the enclosure allows the passage of air and therefore the escape of combustion products in the event of an explosion.

However, this should be long enough and long enough to ensure that such products of combustion are cooled by contact with the walls of the passageway to a temperature low enough to pose no risk of ignition. , is strong.

Passages whose dimensions accomplish this purpose are called "flame gaps" or "flame-proof channels."

An alternative to a flame gap is a gas-tight seal strong enough to withstand the specified explosion pressure within the device, and seal rings meeting this requirement are referred to as "flame-retardant" seals.

This alternative is used in the embodiments of FIGS. 5 and 6.

Then, for the main termination, connect the spigot 20 of the body using the usual method.
It can be installed by screwing into the screw hole.

It will be seen that the second gland member 14 and the insulating compound 12 are both seen at the forward end of this gland.

The termination in FIG. 2 differs from that in FIG. 1 only in that the first gland member 9 is inserted into the rear end 16 of the second gland member 14.

This reduces the risk of compound leakage between the first and second gland members causing them to stick to the shell 11.

The termination in FIG. 3 is similar to that in FIG. 2, except that the second gland member 14 itself acts as the gland barrel 11.

Although this device prevents rotation of the gland shell relative to the cable unless the seal ruptures, it can be inconvenient in certain types of installations.

In another variant embodiment shown in FIG. 4, the first and second gland members 9 and 14 are screwed together at 21.

The outer surface 22 is notched for convenient rotation or provided with two or more flats (not shown) for wrenching.

The termination in FIG. 5 is similar to that in FIG. 2, except that a flameproof seal ring 23 is inserted between the second gland member 14 and the gland body 11, and The termination of FIG. 6 differs in that the ring 23 is accommodated between the rectangular shoulders 24, so that both parts are no longer self-centripetal.

In both of these cases, the sealing ring is preferably factory-fixed to the second gland member (or shell) to prevent accidental release.

Both of these designs can be modified by replacing the ring with a ring of a suitable low temperature setting resin compound (applied in a pasty or viscous state).

Figures 7 and 8 show a 1-continent termination, which is similar to that in Figure 2, except that it does not have an outer seal and has no gland tube or trunk. (Second
Instead of 6 and 11) respectively in the figures, two gland members 25, 26 as alternative attachment means are drawn together using bolts 27 without directly screwing them together.
is used.

FIG. 9 shows a termination according to the invention used in a mineral insulated cable having a copper or aluminum armor 28 with a lead armor (or jacket) 29.

As in the previous formation, the seal is formed by a resin sealing compound 12 press-fitted between the first and second gland members 9 and 14, respectively, both of which are held together by the gland cylinder 6 and the gland cylinder 11. I am drawn to it.

However, in this case the fitting is
, 346,297 as attachment means and a lead insert 3
Attached to the cable end by a seal containing 1.

In order to compress this seal without relative rotation of the gripping surfaces, a pawl washer 32 cooperates with the first gland member 9, and the elasticity of the elastic ring 30 provides a stable sealing action and contact pressure. guarantee a range of capabilities.

FIG. 10 shows a type of termination similar to FIG. 2, except that the first gland member 9 is not attached directly to the cut-back cable end, but instead is used as a standard ( (non-flame retardant) gland 33.

For illustration purposes, EIW Grand (British Standard 6121:1
973), but many other preferred formats can be used.

Further gland members 34,35 perform the main functions of the gland tube and barrel (6 and 11 in FIG. 2) respectively.

While in most cases a fluid-tight seal between the second gland member and the surrounding gland body or other gland member is beneficial, there may be special cases where this is not desirable.

In this case, a continuous flame gap can be ensured by providing ribs, grooves or other suitable shapes in any of these elements.

For example, in FIG. 4, the outer frusto-conical surface of the second gland member is provided with a groove 36 which provides a continuous pressure equalization path from the front face of this gland to a cavity 37 where the armored wire terminates. Guarantee.

Similar equipment may be implemented for other terminations where applicable.

The embodiments of the present invention are as follows.

1. The method of claim 1 for terminating a wire armored cable, wherein the cable end is attached by attaching the armored wire to a first gland member.

2. A method according to claim 1 or embodiment 1, characterized in that the first and second gland members are drawn together by another gland member on a mass.

3. The recess of the first gland member has a frusto-conical bottom and/or the second gland member comprises two parallel parts joined by a frusto-conical inclined part. A method according to Range 1 and any one of the above embodiments.

4. A method according to claim 1 and any one of the preceding embodiments, characterized in that the cable or conduit is attached to the first gland member by a standard gland.

5. The second gland member projects further forward than any other member of the gland, and the insulating compound completely fills the second gland member and projects from the front end thereof. 1 and any one of the above embodiments.

6. Claim 2 for an armored cable, characterized in that the attachment means for attaching the cable or conduit to the first gland member includes an armored wire gripper.
Ground as described in section.

7. The ground according to claim 2 or embodiment 6, characterized in that the drawing means for drawing the first and second gland members together includes another ground member on one block. .

8. The recess of the first gland member has a frusto-conical bottom and/or the second gland member comprises two parallel parts joined by a frusto-conical inclined part 2 and any one of the embodiments 6 and 7 above.

9. The gland according to claim 2 and any one of embodiments 6 to 8 above, characterized in that the mounting means comprises a standard gland.

10. Claim 2 and any one of the embodiments 6 to 9 above, characterized in that the second gland member projects further forward than any other member of the gland. Grand as described in .

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a longitudinal sectional view of a single-person cable termination according to the present invention; Fig. 2 is a longitudinal sectional view of another type of cable termination; Fig. 3 is a more economical and technical FIG. 4 is a cutaway view of another variant termination according to the invention; FIGS. 5 and 6 respectively show other termination types; FIGS. 8 is a longitudinal cross-sectional view and an end view of a pull-bolt type gland termination according to the present invention; FIG. 9 is a longitudinal cross-sectional view of an inorganic insulating cape/'I/termination according to the present invention; and FIG. 10 is a standard gland termination. FIG. 11 is a vertical cross-sectional view of a conventional cable termination using an adapter and an adapter according to the present invention. 1...Cable, 2...Outer coating, 3
......Exterior wire, 4...Inner coating, 5
...Conductor, 6...Ground tube, 7...
...Outer seal assembly, 8...Exterior retainer ring, 9...First gland member, 10...
・・Exterior conical part, 11・・・Gland body, 12・
... compound, 13 ... truncated conical bottom, 14 ... second gland member, 15 ...
...Front end, 16...Rear end, 11...
...Frustoconical middle part, 18...Shoulder part, 19
...flame gap, 20...spigot,
22...Outer surface, 23...Flameproof seal ring, 24...Rectangular shoulder, 25, 26...
...Ground member, 27...Holt, 28
...Exterior (copper or aluminum), 29...
... Exterior (jacket), 30 ... Elastic ring, 31 ... Insert, 32 ... Pawl washer, 33 ... Standard gland.

Claims (1)

Claims: 1. A method of forming a sealed termination at the end of an electrical cable or conduit; a. provision with individual conductors protruding forward from the distal end; a port, said cable or conduit, provided with a recess to be penetrated in the forward facing surface surrounding a passage through which the pre-cte cable passes with the protective layer or the distal end of said conduit; motsu 1
Attaching to the gland member; c. Loading a quantity of curable insulating compound in a pasty or viscous state to fully fill the recess of said first gland member and adhere to said cable or conduit section and the conductor therein; 2. In order to encapsulate the insulating compound sufficiently to create pressure within the compound, a second gland member having a recess in the rearward facing surface is attached to the first gland member.
Assembling to the gland member; e. Before the insulating compound hardens, the first
and applying pressure to the insulating compound by drawing a second gland member together by a pulling means to bring the recesses of the first and second gland members closer together; to the end of the cable or the end of the conduit; is attached to an electrical device, and this mechanical connection to the electrical device is made by mechanically engaging at least one of the ground members with an opening in the case of the electrical device or with an intermediate member attached to the case. and g. the conductor of said cable or the conductor contained within said conduit is electrically connected to said electrical equipment within its case. A method of forming a sealed termination at the end of an electrical cable or conduit. 2. A first gland member having a passageway for a cable or conduit; attachment means for attaching a cable or conduit to the first gland member; and a second gland removably engaging the front end of the first gland member at its rear end. and a pulling means for drawing the first and second gland members together; the first gland member has a recess surrounding a passage on its front surface, and the second gland member has a recess on its rear surface. , and a recessed portion of the first gland member to form a compound chamber.