RO133730A2 - Metallic stuffing box for electric cables of large diameter - Google Patents

Abstract

The invention relates to a mono-block metallic stuffing box, meant to seal cables of large diameter or metallic pipes. According to the invention, the stuffing box is used to seal electric cables or pipes (7) of large diameter and it consists of a metallic body (3) of the stuffing box, which has a single end with metric external thread, which is used to mount the stuffing box on a metallic wall (8) of the switchboard, a ring-like rubber gasket (2), used to seal the stuffing box onto the metallic wall (8) of the switchboard, a hexagonal metallic metric nut (1), which is clamped onto the body (3) of the stuffing box and a toroidal rubber tube (4) with a valve (5), which is used to seal the lateral surface of the electric cables or pipes (7) to the body (3) of the stuffing box, on the exterior of the body (3) of the stuffing box there being a fixed hexagonal area for wrench blocking, needed upon mounting the stuffing box on the switchboard, and for the right placement of the rubber tube (4), inside the body (3) of the stuffing box, on the side opposite to the threaded area, there is a specially built area, the body (3) of the stuffing box having an orifice through which the valve (5) of the rubber tube (4) passes to the exterior, and in order to provide adherence of the rubber tube (5) to the body (3) of the stuffing box, when the tube is deflated, there is an adhesive surface (6), where, after mounting the stuffing box on the switchboard and installing the cable, inert gel under pressure is introduced through the valve (5), so that the rubber tube (4) tightens the electric cable or the pipe (7) onto the body (3) of the metallic stuffing box, on the lateral surface, even if the cable cross-section has not a perfect circular shape.

Description

The invention relates to a single-body metal cable gland for sealing large diameter cables or metal pipes, passing them through the wall of an enclosure. The cable gland consists of the metal body, the toroidal chamber with filling valve - emptying, the rubber gasket and the locking nut (fig. 1). The body of the cable gland is constructed in such a way as to allow the insertion of a rubber chamber with a valve. The rubber tube with the valve is the sealing element between the outer surface of the electric cable and the inner surface of the body of the cable gland. Inert rubber introduces an inert gel that inflates the toroidal chamber to its maximum contact with the outer surface of the cable or pipe. The toroidal chamber deformation allows perfect sealing regardless of the geometry of the cross section of the cable, including in the case of reinforced cables with apparent spiral.

The cable gland can have different areas of use:

transmission, distribution and use of electricity;

the car and plant construction industry;

metal operating cabinets.

The plastic or metallic cable glands are known, with tightening (collating) elements of the armed electric cables that allow the cables to pass through the wall of the electrical panels. By tightening the electrical cables, along a certain length, the sealing is ensured, but the electrical conductors in the cables can be affected [1,2]. Some cable glands can be constructively complicated, having two or even three threaded areas [3-5] or more component parts, of metal and / or plastic [6-11]. The use of a large number of components reduces the reliability of the entire construction assembly and increases the workmanship. At the same time, the price of cable glands increases.

Some cable glands used for electric cables have truncated clamping areas, sometimes even with several areas, made of metal or plastic, and rubber gaskets [2,12]. Large diameter reinforced electrical cables are particularly rigid and can damage the cable gland through the large table and section they have. The trunk areas in the cable glands can be the components of low cable gland reliability.

Other cable glands, by the construction they have, can cause a very good tightening of the armed cables. However, they do not allow their use for a wide range of diameters of the armed electric cables, for the same size of the cable gland [13-15].

Some cable glands can be very simple from a constructive point of view, as they may have one or two rubber components [16,17]. Although they are made of rubber, they cannot be used for large diameter reinforced cables, but only for ordinary electrical cables (without reinforcement).

Special cable glands have also been built, which in addition to the passage of the electric cable through a switchboard, also allow the cable to be dismantled in the electrical conductors and the fixing of the electrical conductors in the sockets [1,3-5,18].

The cable glands for reinforced electrical cables can be used for more diameters of electrical cables, up to diameters of the electrical cables approximately 30% smaller than the inside diameter of the cable gland [19]. Other cable glands have been made for a wider range of diameters, but for flexible cables with flexible conductors [20].

The metal cable gland for electric cables or large diameter pipes (fig. 1), which is the subject of the present invention, has the following advantages:

- it is simple from the constructive point of view, as compared to other types of cable glands, having only four component elements;

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02/05/2018 due to the fact that it has fewer components of low complexity, it has a low cost price compared to the existing glands on the market;

adapts well to irregular surfaces of large diameter reinforced electric cables;

a gland with a given inner diameter, can be used for a wide range of electrical cables of different diameters;

is reliable in operation;

the process of sealing the cable / pipe is executed in a very short time, on the order of the seconds, it does not require a dynamometric key nor any special technical skills;

the amount of air initially present in the toroidal chamber acts as a buffer element and allows the contact pressure between the toroidal chamber and the outer insulation of the cable to be maintained even under varying temperatures.

The metal cable gland used for large diameter electrical cables that are the subject of the present invention is formed by the metal body of the cable gland 3, which has a single end with outer thread (metric), which is used for penetrating the cable gland through the metal wall 8 of the electrical panel ( fig.2,3). On this threaded end of the metal gland a ring rubber gasket 2 is used, used to seal the gland on the metal wall of the electrical panel. For attaching the cable gland to the electrical panel, a hexagonal metal nut 1 (metric) is used which attaches to the threaded area of the body of the cable gland 3. The body of the cable gland 3 has a fixed hexagonal area on the outside, in the form of a nut useful for mounting the cable gland on the metal wall 8. of the electrical panel. Inside the body of the cable gland 3 is an area so constructed that a rubber chamber 4 with valve 5 can be inserted which is used for sealing the lateral surface of the electrical cables 7 to the body of the cable gland.

3. The body of the casing 3 has an opening through which the valve 5 of the rubber chamber 4 passes externally. Between the outer lateral surface of the rubber chamber 4 and the inner surface of the body of the casing 3 there is an adhesive surface 6 with the role of maintaining the rubber chamber. 4 when deflated. When installing the cable gland on the wall 8 of the electrical panel, the electric cable 7 is inserted through the body of the cable gland 3 and the rubber chamber 4 with the valve 5, the hexagonal metal nut is tightened 1. The valve 5 introduces inert gel under pressure (1,5- 2 bar) so that the rubber chamber 4 will seal the electric cable 7 from the body of the metal cable gland 3. After the inert gel is introduced, the valve 5 will be protected by a cap. The cable gland can be built in different sizes, M50xl2.5 M63xl, 5, M75xl, 5, M90x2, M110x2.

Compared to other types of cable glands used for large diameter electrical cables, the cable gland, according to the invention, has only four components: hexagonal metal nut 1, rubber gasket 2, body of cable gland 3 which has only one threaded end, and on the opposite side, Inside is an area so constructed that a rubber chamber 4 with valve 5 is introduced. Due to the few components, and relatively simple from a constructive point of view, the cost of the cable gland will be lower compared to other types of cable glands. In practice, it is known that the cross-section of large diameter electric cables is not always perfectly circular, sometimes there can be a difference of 5-7% between the maximum and minimum diameter of the electric cable. Also, a given size cable gland can be used for a relatively small range of electrical cable diameters. Typically, the glands that have a sealing element deformable by compression ensure the sealing of cables with diameters up to 20% smaller than the inner diameter of the gland. By using the rubber chamber 4 with inert gel under pressure, a degree of sealing up to IP 65 can be provided and for cable diameters up to 50% smaller than the inner diameter of the cable gland. Thus, less cable glands (in terms of size) can be built for a wider range of electrical cables.

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Bibliography:

1. US Patent No. 3993330 dated November 23, 1976

2. Patent US 3990661 of November 9, 1976

3. US Patent No. 4273405 of June 16, 1981

4. US Patent No. 5,155,991 of May 7, 1985

5. US Patent No. 5,310,963 of May 10, 1994

US Patent No. 4,629,825 of December 16, 1986

7. US Patent No. 4692563 of September 8, 1987

8. US Patent No. 56,21191 dated April 15, 1997

9. US Patent No. 5691505 of November 25, 1997

10. US Patent No. 6812406 B2 of November 2, 2004

11. US Patent No. 85,13543 Bl of August 20, 2013

US Patent No. 45,49037 of October 22, 1985

13. US Patent No. 5,494,755 of October 29, 1985

14. US Patent No. 5,597,477 of October 22, 1991

15. US Patent No. 80,13250 B2 of September 6, 2011

16. US Patent No. 4912287 dated March 27, 1990

17. US Patent No. 8,170,390 B2 of May 1, 2012

18. US Patent No. 5,324,2436 of July 2, 1996

19. US Patent No. 5951327 dated September 14, 1999

20. US Patent 6259029 July 10, 2001

Claims (3)

1. Metal cable gland for large diameter electric cables, typed. Pxjp ^ cee ^ that it is formed by the metal body of the cable gland (3), which has a single end with a lynx (metric), a hole on the side surface and a special construction. Inside, a ring rubber gasket (2), a hexagonal metal nut (1) (metric) and a toroidal rubber chamber (4) with a valve (5). 1. The principle of sealing between the body of the cable gland 3 and the electric cable 7, by using the toroidal rubber chamber 4 with valve 5, in which inert gel is introduced under pressure, after the installation of the large diameter cable. 2. Metal cable gland for large diameter electrical cables, characterized in that it has the principle of sealing between the body of the cable gland (3) and the electric cable (7), by using the toroidal rubber chamber (4) with valve (5), in which introduces inert gel under pressure, after installing the electric cable (7). 02/05/2018 EXPLANATORY DRAWINGS Fig.2. Cable gland assembled for large diameter electrical cables Figure 3. Longitudinal section through the cable gland after sealing a large diameter electric cable of 2018 00303 I OSIM I ^17/01/2019 I row reframed I ........... I Claimed claims, according to the notification A / 00303 / 30.07.2018, for the patent application no. A 00303 2018 from 02.05.2018 with the title Metal cable gland for large diameter electric cables 2. The component parts of the metal cable gland, which are used for large diameter electrical cables 7, and which is formed by the metal body of the cable gland 3, which has a single end with a fixed outer thread (metric), a hole on the side surface and a special interior construction, an annular rubber gasket 2, a hexagonal metal nut 1 (metric) and a toroidal rubber chamber 4 with a valve 5. 3. The construction of the body of the casing 3, which externally has a fixed hexagonal area, for locking with the key, and for the correct placement of the rubber chamber 4 inside the body of the casing 3 is a specially built area, on the opposite side of the threaded area. The body of the casing 3 has an opening through which the valve 5 of the rubber chamber 4 passes outwards, and to ensure adhesion to the body of the casing 3 of the rubber chamber 4, when the chamber is deflated, there is an adhesive surface 6. to 2018 00303 3. Metal cable gland for large diameter electrical cables, according to claims 1 and 2, characterized in that, for the purpose of sealing, the body of the cable gland (3) has on the outside a fixed hexagonal area, for key locking, and for the correct placement of the key. the rubber chamber (4) inside the body of the casing (3) is a specially constructed area, on the opposite side of the threaded area, and the body of the casing (3) has an opening through which the valve (5) of the rubber chamber (4) passes through the outside , and to ensure adhesion to the body of the rubber casing (3) of the rubber chamber (4), when the chamber is deflated, there is an adhesive surface (6).