DE3100863A1 - PIPE SEAL - Google Patents

Description

Line sealing

The invention relates to a sealing of line bushings between the pressurized space and the atmosphere, consisting consisting of electric cables, conductor connection bolts and seals or insulation, especially for electric motors with glandless ones Circulation pumps.

Seals of cable bushings for electric motors are generally known, e.g. as a stuffing box design (DE-PS 715 496, DE-AS 27 30 675, DE-GM 77 05 153). With these bushings, the insulation or sealing between two Clearing partly with insulating material, partly with O-ring seals performed.

In the case of circulating pumps without stuffing box, preferably in the use of nuclear power / verken, there is a seal between the pressurized Space and the atmosphere (see Fuel - Heat - Kraft 31 (1979), No. 4, April, Chapter 4, Page 176), the pressure differences are approx. 110 bar. The insulation thicknesses are according to the required voltages

or streams to be specified. This primarily determines the dimensions of the cable bushing and the dimensions of the conductors. the In most cases, conductors are soldered to the corresponding cable, with the insulation using heat-shrink tubing and insulating tape is made. The insulation between the bushing wall and the conductor is usually massive Insulating sleeves, e.g. made of hard rubber or ceramic, realized. In addition, elastomers - for example O-rings - used. These materials are temperature wise designed for normal operating conditions.

The disadvantage of the 'known designs is not reliably ensures that there is still a reasonably tight seal in the case of defective insulating bodies.

The object of the invention is to design a cable bushing system in such a way that the necessary insulation wall thicknesses are achieved and in case of overheating, d. H. if the isolators are destroyed, a seal between the pressurized room and the atmosphere is guaranteed despite the insulating body being destroyed. Above all under the aspect that no primary medium can escape from the reactor pressure vessel and a cable break is avoided.

The object is achieved by a seal for cable bushings of the type mentioned at the outset, with one embedded in the insulating compound between the pressurized space and the atmosphere and if the insulation is destroyed or can be permanently pressed outwards by the internal pressure onto a type of valve seat, as a valve body trained conductor connection bolt, which through its geometric shape opens the opening that is exposed by the melted insulating body locks. This creates a non-return valve effect and there is largely an escape of those under pressure Liquid prevents. Furthermore, overpressure in the cable box is avoided.

The measure according to the invention also provides that the distance between the cone and metal support is designed so that the The elasticity of the connecting cable prevents tearing and the projection area of the cable cross-section is prevented by the dimensions of the insulating body is dimensioned in such a way that overstressing of the insulating body in the cone area is excluded.

1 to 5 illustrate the seal for line bushings according to the invention with the pressurized End wall 1 between the pressurized room and atmosphere, with the conductor connection bolt 2, an insulating body 3 from Hard rubber or ceramic, an insulating body 4 made of hard rubber,

the current-carrying cable 5 from the winding, a stop ring 6 made of non-magnetic material and also with two layers Insulating tapes 7, 8 and a shrink tube 9 as well as a nut 10 for pretensioning the cable connection bolt 2 together with an O-ring 11 for sealing between the housing wall and Insulating body.

The connecting bolt 2 is designed with a slope that is like this is dimensioned that the maximum diameter with a minimum predetermined distance for the insulation to the housing wall or stop ring 6 can be realized. Instead of the incline, a straight surface - as shown in FIG. 3 - can also be implemented will. A separate ring 6 made of non-magnetic material is provided as a stop, which is attached to the support point, as shown in FIGS. 4 and 5, it can optionally be designed with a corresponding bevel or a radius. Depending on Material pairing and internal pressure, the appropriate support corner is selected between sharp-edged and angled. At the Failure of the insulation body 4 is caused by the internal pressure of the connecting bolt 2 against the ring or against the corner printed and thus achieved a self-seal through the internal pressure. The loosely inserted stop ring 6 can after

Dismantling can be exchanged in the event of destruction. In principle, the seal can also be carried out without this separate ring, the housing wall must be dimensioned accordingly.

The main advantages of the invention are self-sealing Cable entry system during normal operation and accidents, i.e. no liquid escapes into the atmosphere, an exchangeable one Seat through a separate ring, the use of elastic insulating bodies with good insulating effect, which in the event of overheating Do not impair the seal due to accidents or the possibility of exchanging conductor connections and support rings after accidents by unsoldering and re-soldering a solid conductor as well as by changing the stop ring with the corresponding insulating bodies, through short axial movements or elasticity of the electrical cables within the motor, which avoid tearing the electric cable.

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Claims (1)

Klein, Schanzlin & Becker Aktiengesellschaft Installment entitlement Γ \ Sealing for line lead-through between the pressurized room and atmosphere, consisting of electric cable, conductor connection bolts and seals or insulation, especially for electric motors in glandless circulating pumps, characterized by an embedded in the insulating compound between the pressurized room and the atmosphere and if the insulation is destroyed or permanently off Internal pressure to the outside on a type of valve seat pressable, designed as a valve body conductor connection bolt (2).