Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to a high voltage
metal-clad circuit breaker.
In particular, the invention relates to a
high voltage metal-clad circuit breaker having an elonyated
vertical metal tan]c, obturated by a top cover and filled
with a high dielectric strength gas, the active part oE
the circuit breaker of column-shape be:ing placed in said
tank and lying on the lower bottom of the tank by insulat-
ing feet.
A metal-clad circuit breaker of the mentioned
type, for example described in the U.S. Patent No. 3,895,202,
can reach a height of several meters, and the oscillations
resulting from a shock during the shipment or when an earth-
quake occurs, can generate excessive stresses and damages
of the active part located in the tank. The conventional
solutions oE clamping i.t during the shipment cannot be
applied when the tanks are sealed and filled with gas at
the factory, and they do not solve the problems abou-t earth-
quakes.
An object of the present invention is to remedy
to these disadvantages and to permit the realization of
a strong fixing device allowing a differential thermal
expansion of the constituent parts of the circuit breaker.
According to the present invention, there
is provided high voltage metal-clad circuit breaker compri-
sing an elongated vertical gas tight metal tank having
a top cover and a lower bottom and filled with a high die-
lectric strength gas, an active part of the circuit breaker
of column-shape placed in said tank and having an upper
part and a lower part, insulating feet lying on the lower
bottom of the tank and supporting the lower part of said
active part and at least two elastic s-tays secured to the
upper part of said ac-tive part and to said tank Eor exerting
a radial cornponent to maintaln the ac-tive part in position.
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Preferably, the stays radially extend between
the upper part of the active part and the cover, being regu-
.arly distributed on the active par-t circumference.
The elasticity of the stays permits a compensa-
tion of thermal expansions enough to limit the stressesexerted on the active part of the circuit breaker.
The stays number ~an be increased depending
of the intensities of forecast earthquakes, the minimal
number being two.
Preferably, the stays are constituted by an
insulating rod ensuring the insulation between the active
part of the circuit breaker and the generally grounded
metal tank, the insulating rod carrying at its ends anchor
parts one of which presents a set screw. The stay shows
an elasticity at the compre.ssion and at the traction from
a rest equilibrium position, and the adjusting device per-
mits, the mounting being carried out a-t a room temperature
of 15 to 20C, to exert no force on the active part of
the circuit breaker. When the temperature increases or
decreases the stays will be compressed or stretched but
will always ensure a force to center the column.
I-t is advantageous to hinge the stays on the
upper part of the active part for preventing any s-ticking
of the column.
Other advantages and technical data will rnore
clearly appear from the following description given as
example, without limitative manner, wherein reference is
made to the accompanying drawing, in which:
Fig. 1 is an axial sectional schematic view
of a circuit breaker according to the invention.
; F'ig. 2 is a view on an enlarged scale of a
stay according to Fig. l;
Fig. 3 is a top view, showing the two fixing
stays according to Fig. l;
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Fig. 4 is a view similar to the one on Fig.
3, showing a fastening with three stays.
On the Figures a cylindrical metal tanlc 10
is vertically disposed on a supporting frame 12. I'he -tank
is tightly obturated by a top cover 14 and is Eilled
with a high dielectric strength gas, such as the sulfur
hexafluoride under pressure.
Inside the tank 10 is coaxially disposed a
column 16 forming the active part of the circuit breaker.
The active part 16 comprises four break gaps series connec-
ted and each disposed between two successive plateaux 18
connected by insulating spacers 20. The column 16 lays
on the bottom 24 of the tank 10 by means of an insulating
base 22. Tight bushings 26, 28, connected to the lower
and upper plateaux 18 respectively, constitute the entran-
ces and
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outlet~ of the circuit breaker. It is u~ele~s to de~cribe More in
detail suoh a circuit breaker~ whi.oh ~ormg th~ subjeot of the pre-
cited U.S. Pat~n-t N 3~895~202 to whioh i-t shall be ad~an-tageou~ly
referred. It is clear that the number o:~ break gap~ can be diffe-
rent.
According to the present invention~ two stays 30~ 32 are anchored
on the one hand to the upper plateau 18 o~ the colurnn 16, and on
the other hand to the cover 14 or more exaotly to a flange 34 to
fasten the cover 14, obliquely extending in a diametral plane of
the tank 10. The stays 30~ 32 are identical and only one 30 of them
will be described in detail referring to Fig. 2 . The s-tay 30 com-
prises an insulating rod or connecting rod 36 rigidly secured at
its ends to anchor parts 38~ 40. The pcart 38 is hinged by a ball
42 on a fork-joint 44 bolted on the upper plateau 18. The opposite
anchor part 40 presen-ts a telescopic connection 46 constituted by
a sliding fastening rod 48 coaxial by extending in a housing 50 of
elastic washers 52. The fastening rod 48 carries a flange 54 inter-
posed between the elas-tic washers 52, which attract the rod 48 in
an equilibrium intermedia-te position. The elastic connection 46
permits a shortening and an elongation of the stay 30 agains-t the
elastic forc~f springs or washers 52. The fastening rod 48
threaded at its ends is secured to a support 58 by two set nuts
569 itself secured to the flange 34. 'rhe support 58 can be fas-
tened to the flange 34 by screws 59, ~ihich advan-tageously are the
screws or bolts to fasten the cover 14. Thus is avoided any punc-
ture of the tank 10 or coYer 14 or any additional fastening part
The telescopic connection 46 is accornmodated to permit a slight
rotation of the stays~ and it is useless to pro~ide for on the
side of the anchor part 40 a fastening ball similar to the ball 42
of the part 38 The stay 30 obliquely extends and it is easy to see
that it i~ capable of exerting a radial component on the plateau
18 of the column 16 upper part. The lnclination angle of the stay
30 is of course function of the fastening point 4~i on the upper
plateau 18 and of the gap between this plateau 18 and the cover l~.
According to the invention the de~ice is brought into play according
to the following manner :
The stays 30~ 32 are set before the placing of the cover 1~ and
the set nutg 56 arc clamped so a~ that at a room temperatur~ of
nearly 15 to 20C the telescopic connec-tion 46 i~ in the equili-
brium position. In this position the stay~ 30~ 32 do not exert any
force on the upper plateau 1~ and ar~ inactive. rl'he inYulation rod
36 of the stays 30~ 32 ensures the insulation be~ween the active
part 16 and the metal tank 10, and the tank can be filled with
sulfur hexafluoride under pressure-in the ~actory~ of course after
closing the cover 14 . It is understood that, when a shock or an
earthquake occurs leading for example to shift the upper part of
the column 16 towards the right on ~ig. 1, the stay 30 is com
pres~ed, whoreas the ~tay 32 is elongated. ~he elastic telescopic
connection 46 of the stays 30, 32 work against this shortening and
this elongation and exert on the plateau 18 a reaction leading to
maintain the column 16 in its middle position. The reaction depends
of the characteristics of the elastic ~ashers 52; which will be
chosen in consequence~ Any excessive displacement capable of dama-
ging the column 16 is thus avoided. It is convenient to note that
a displacement of the upper plateau 18 in a plane perpendicular to
the one of Fig. 1, induces an elongation of the stay~ 30, 32 and a
centering reaction as it is described above. It is clear that the
stays 30, ~2 exert this centering force whatever the displacement
direction of the upper plateau 18. When there is a temperature
variation the spacing between the upper plateau 1~ and the cover
14 varies because of the different thermal expansion~ of the tank
10 and the column 16. ~hen the upper plateau 18 moves apart from
the cover 14, the stays 30~ 32 are elongated by putting the elastic
connection 46 under tension. This presentation does not modify the
centering force exerted by the stay~ 30, 32 when the column 16
oscillates. Tha elongation of -the stays 30~ 32 involves a rela-tive
rotation permitted by the balls 42 and the el,;~tic connection 46.
The centering force obtained by two stays 30~ 32 i9 differen-t acc~r-
ding cas the di~placemen-t occurs in the stays plane or in a perpen-
dicular one, and it is advantageou~ to u~e a superior nwllber of
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stays, for exc~mple -three or four~ the re~llar distribu-tion being of
course respected, ~ . 4 illustrate~ ag.an exaMple.a fixin~ with
three stays disposed at an an~le o:f ~0. The etca~,numbers ~iill be
chosen depending of the intensities of predicted ~hock~ or earth-
ouakes.
The invention is not at all liMited -to the embodirrients mor0 fully
described~ but on the contrar~y it ex-tend6 to any varirlnt~ in par-
ticular to the one in whioh the ~st(?,y~ 30~ 32 would be consti-tuted
in an elastic cast solid p.3rt~ or to the one in ~:rhich the stay~ 30,
32 ~ould extend in a radial direction.
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