Field of Invention:
The present invention relates to nozzle with bidirectional flow for current
interruption in a gas circuit breaker, and more particularly to trans axial flow
insulated nozzle for a moving piston puffer type gas circuit breaker.
Background And Prior Art:
Puffer type gas ciruit breakers are employed to interrupt normal and short
circuit current generated during fault conditions in a high voltage transmission
system. In a puffer type gas circuit breaker with insulated nozzle, gas is stored in
an enclosure at a predetermined high pressure and further compressed by
cylinder piston action to a higher pressure in a compression chamber generally
termed as a puffer or blast cylinder. The compressed gas from the blast cylinder
is discharged through an insulated nozzle with a very high velocity to blow out
the high temperature arc plasma that is struck between a pair of contacts. The
arc surrounded by the envelope of high pressure gas eventually gets lengthened
and quenched to interrupt the flow of current.

Indian patent No. 217361 dt. 4/11/2008 disclosed puffer type gas circuit breaker
with movable piston and metallic blast cylinder in which the moving piston
compresses gas within a fixed metallic blast cylinder as opposed to the then
state of art circuit breakers, wherein a moving cylinder compresses the gas
against a fixed piston.
In the interrupter of the gas circuit breaker disclosed by the prior patent No.
217361 dated 4.11.2008, flow of the compressed gas from the blast cylinder
through the insulating nozzle is unidirectional and axial in nature, thereby
effecting the arc cooling and deionization process, thus limiting the current
interrupting capability of the interrupter.
Moreover, the thermal recovery process of the gas circuit breaker after current
interruption is limited due to unidirectional flow.
The trans axial flow insulated nozzle in accordance with the invention seeks to
overcome the above drawbacks of the prior art.

EP1109187 discloses the hybrid circuit breaker has at least two series-connected,
operated by a common drive or by separate drives, filled with different arc
extinguishing media extinguishing chambers (2,3).
EP1149446 is to provide three-phase encapsulated high-voltage circuit breaker
which is arranged horizontally, compact, and as low in height as possible and
requires as little mounting space as possible. To this end the tubular circuit-
breaker housing has a connecting flange on each of its face ends for horizontally
connecting a built-on housing and the control device is fixed to a mounting
flange positioned in the area of the outer jacket of the circuit-breaker housing.
EP1117114 relates to a power use circuit breaker and an electrical circuit
arrangement for an electrical power generating plant using such power use
circuit breaker.
OBJECTS OF THE INVENTION
1. It is therefore an object of the invention to provide a bidirectional (radial and
axial) passage for gas flow within the arc quenching insulating nozzle during
current interruption process.

2. Another object of the invention is to ensure flow of gas in a direction
perpendicular to the arc length (trans-axial) in addition to the already
existing axial direction.
3. A further object of the invention is to reduce the arc cross-section by
introduction of a transverse or radial compressed gas flow through the
insulating nozzle.
4. Yet another object of the invention is to improve the current interruption
ability for an insulated nozzle puffer interrupter with movable piston and
fixed metallic blast cylinder.
Summary Of The Invention:-
Accordingly there is provided an improved blast interrupter of a puffer type
gas circuit breaker interrupter, comprising a movable piston in a metallic blast
cylinder for interrupting high electric current. An insulated nozzle with bi-
directional (axial and transverse) compressed gas flow is provided to improve
the interrupting capability of the gas circuit breaker interrupter.
The transverse direction is also called radial direction in this specification.

Brief Description Of The Accompanying Drawings:
The proposed invention will be better understood from description with
reference to the accompanying drawings in which
Figure 1 represents a puffer interrupter for gas circuit breaker with moving
piston, metallic blast cylinder and insulating nozzle with unidirectional
(axial only) gas flow according to the prior art.
Figure 2 represents a puffer interrupter for gas circuit breaker with moving
piston, metallic blast cylinder and insulating nozzle with bidirectional
(axial and radial) gas flow according to the present invention.
Figure 3 represents a detailed view of both axial and radial flows of the
compressed gas with passages indicated for both flows in the
insulating nozzle for the gas circuit breaker interrupter according to
the present invention.
Description of the invention:
An exemplary embodiment of the invention as depicted in the accompanying
drawings will now be described. However, there can be several other

embodiments of the same invention, all of which are deemed covered by this
description.
As shown in the prior art interrupter for gas circuit breaker comprises in
figure 1; an insulating chamber (1); a fixed contact system (2) a moving
contact system (3); a fixed contact terminal (4); moving terminal (5); a fixed
contact support (6); a normal current contact (7); a fixed arcing contact (8);
a high voltage shield (9); a movable contact support (10); a metallic blast
cylinder (11); a movable piston (12); an insulating nozzle (13); a moving
arcing contact (14); a link to mechanism (15); and a movable contact tube
(16). The isolating gap and the corresponding volume are represented
respectively by the alphabets "A" and "B" in figure 1.
Gas is stored at a high pressure in the insulating chamber (1), and the gas is
further compressed to higher pressure inside the metallic blast chamber (11) ,
and the movable piston (12) effects the gas compression. The insulating
nozzle (13) blows the high pressure compressed gas over the high
temperature arc that is struck between the pair of fixed (8) and moving (14)
arcing contacts.
The efficiency of a_gas_circuit breaker depends upon how quickly the high
temperature arc can be extinguished or "blown out". The interrupting

capacity of a circuit breaker, given in Amperes, goes up if the blow-out is
achieved in shorter time.
In the prior art, such circuit breakers, which blow out an arc with compressed
gas, depended on unidirectional flow of the gas which was fed to the arc in
the direction of the axis of the arc. Such axial flow of the gas did not effect
reduction of the cross sectional area of the arc, which plays a vital role in the
strength of the arc. An arc can be handled more easily and extinguished
quicker, if the cross-sectional area of the arc can be reduced. The present
invention achieves a reduction of the cross-sectional area of the arc by
providing an additional trans-axial or radial gas flow. It therefore increases
the short circuit current interruption capacity of such a circuit breaker.
Figure (3) shows the detailed view of the radial and axial gas flow with
passages effecting these flows. The constituent components of the
interrupter are identical to that shown in figure (1). The improvement on the
prior art of figure 1 is characterized by additional radial flow passages (17) in
the insulating nozzle (13) to generate radial gas flow as shown in figures 2
and 3 for faster cooling of the hot ionized gas developed due to the arc
generated while opening of the interrupter during current interruption. Thus a
radial passage for compressed gas flow within the arc quenching insulating
nozzle is provided to convert the unidirectional gas flow to bidirectional flow

(axial and radial) during the current interruption process and increases the
compressed gas mass flow in the insulating nozzle (13). This additional radial
flow assists in reduction of cross section of the arc and improvement in short
circuit current interruption capacity from 25000 amps to 31000amps for the
said interrupter.

We Claim
1. A trans-axial flow insulated nozzle device for gas circuit breaker comprising a
single insulated chamber (1), a fixed contact system (2), a moving contact
system (3), a fixed contact terminal (4), a moving contact terminal (5), a fixed
contact support (6), a fixed current contact (7), a pressure propelled fixed
arcing contact (8), a moving arcing contact (14), a high voltage shield (9), a
metallic blast cylinder (11), a movable piston (12), and an insulating nozzle (13),
characterized in that an additional radial and axial flow passages are provided in
the insulating nozzle (13) to generate a transverse flow in addition to axial flow
of compressed gas which provides a trans-axial blast in the movable piston (12)
and the fixed metallic blast cylinder (11) including generating a pinching effect
on the arc struck between the pressure-propelled fixed arcing contact (8) and
the moving arc contact (14) and thereby reduces the arcing time and improve
thermal recovery characteristics during current interruption process.
2. An insulating nozzle as claimed in claim 1, wherein said radial gas flow effects
reduction in cross-section of the arc struck between the pressure-propelled fixed
arcing contact (8) and the moving arcing contact (14).
3. An insulating nozzle as claimed in claim 1, wherein the radial and axial flow
passages increase the compressed gas mass flow in the insulating nozzle (13). -

4. An. insulating nozzle as claimed in claim 1, wherein said radial gas flow
through the radial flow passages (17) enhances the short circuit current
interruption capacity from about 25000 Amperes to about 31000 Amperes.

ABSTRACT

TITLE: Trans axial flow insulated nozzle for Gas Circuit Breaker
The invention relates to a trans-axial flow insulated nozzle device for gas circuit
breaker comprising a single insulated chamber (1), a fixed contact system (2), a
moving contact system (3), a fixed contact terminal (4), a moving contact
terminal (5), a fixed contact support (6), a fixed current contact (7), a pressure
propelled fixed arcing contact (8), a moving arcing contact (14), a high voltage
shield (9), a metallic blast cylinder (11), a movable piston (12), and an insulating
nozzle (13). An additional radial and axial flow passages are provided in the
insulating nozzle (13) to generate a transverse flow in addition to axial flow of
compressed gas which provides a trans-axial blast in the movable piston (12)
and the fixed metallic blast cylinder (11) including generating a pinching effect
on the arc struck between the pressure-propelled fixed arcing contact (8) and
the moving arc contact (14) and thereby reduces the arcing time and improve
thermal recovery characteristics during current interruption process.