F O R M 2

THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)

1. Title of the invention: AN IMPROVED ARC CHUTE ASSEMBLY FOR USE IN SWITCHGEAR DEVICES

2. Applicant(s):

(a) NAME : LARSEN & TOUBRO LIMITED

(b) NATIONALITY : An Indian Company

(c) ADDRESS : L & T House, Ballard Estate, Mumbai 400 001,
State of Maharashtra, India

3. PREAMBLE TO THE DESCRIPTION

The following specification particularly describes the invention and the manner in which it is to be performed:


FIELD OF THE NVENTION

The present invention relates to an arc chute assembly. More particularly, the invention is concerned about an improved arc chute assembly for use in switchgear devices.

BACKGROUND OF THE INVENTION

EP 2278599 (A2) discloses an arc chute assembly (100) is provided for an electrical switching apparatus (2). The electrical switching apparatus (2) includes a housing (4) and separable contacts (16) enclosed by the housing (4). An arc is generated in response to the separable contacts (16) being separated. The housing (4) includes a number of arc chambers (6,8,10) each having a first side (12) and a second side (14) disposed opposite and spaced apart from the first side (12). The arc chute assembly (100) includes a plurality of first arc plates (106) extending outwardly from the first side (12) of a corresponding one of the arc chambers (6,8,10) toward the second side (14) of the corresponding one of the arc chambers, and a plurality of second arc plates (108) extending outwardly from the second side (14) of the corresponding one of the arc chambers (6,8,10) toward the first side (12) of the arc chamber. None of the arc plates (106,108) engages the opposing side of the arc chamber

US 7,705,263 discloses an arc chute assembly includes a housing having a lateral axis and a quenching portion disposed within the housing. The quenching portion includes at least two deion plates being spaced along the lateral axis of the housing and each having a cut portion wherein the cut portions are staggered along the lateral axis with respect to one another and are configured to mitigate an arc.

The disadvantages of the switchgear devices are such that with the ever-increasing cost of raw materials viz. plastics and metals, the situation has become advertent towards a product with better performance and value for money. With this in mind, it has become imperative for switchgear industry to have a product with better performance and "higher "life".

Thus, there is a need to overcome the problems of the prior art. There is a need of having a system which is effective in quenching the arc at first current zero and there is no re-ignition of arc. Also there is a need of having higher arc lengthening as it's detrimental in quenching the arc early. So, present inventors have developed an improved arc chute assembly for use in switchgear devices. The direct implementation of this invention is to have a mechanism which quenches the arc in short time.

OBJECTS OF THE INVENTION

An object of the present invention is to overcome the problems/disadvantages of the prior art.

Another object of the present invention is to provide an improved arc chute assembly for use in switchgear devices.

These and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided an improved arc chute assembly for use in switchgear devices, said assembly comprising:
plurality of deion plate means being operatively arranged in said arc chute assembly
wherein said plate means adapted to have non-uniform length and
wherein said plurality of plate means comprising non-uniform gaps therebetween.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Other features as well as the advantages of the invention will be clear from the following description.

In the appended drawings:

Figure 1 illustrates an isometric view of the filling apparatus according to an embodiment of this invention.

Figures 2 and 3 illustrate a side view of the arc chute assembly having deion plates.

The drawings illustrate one preferred embodiment presently contemplated for carrying out the invention. In the drawings: (another way of writing)

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and illustrate the best mode presently contemplated for carrying out the invention. Further functioning of the assembly has been discussed below to describe the way the assembly operates. However, such description should not be considered as any limitation of scope of the present unit. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.

According to the invention there is provided an improved arc chute assembly for use in switchgear devices. The present invention relates to switchgear devices where its application helps in effective and faster arc quenching by not allowing the spent gases to come back to arcing region (prevents re-ignition). As shown in figures 2 and 3, the deion plates (1) are arranged in such a way that these are tilted and not parallel with respect to each other and height of deion plates (1) is varying such that it creates a gas dynamic effect which in turn facilitates the motion of arc in the desired direction and doesn't allow the gases to come back and reignite (funneling or sucking out effect), thereby aiding the arc quenching process.

As shown in figure 3, it is evident that the distance between any two deion plates (1) is lesser at bottom and higher at top i.e. L2 > L1. This configuration of deion plates (1) works and improves the performance in the following way.

As shown in figures 2 and 3, deion plates (1) with their height progressively increasing (in horizontal direction) and the gap between the deion plates (1) progressively increases as we move up vertically i.e. the deion plate are arranged in a tilted fashion with respect to each other.

Because of the lesser gap at bottom and larger gap at top, gases coming from bottom side will see lesser volume in front and larger volume at the top (end side), which will facilitate the motion of gases from bottom to top due the pressure difference. The pressure difference is a result of gas expansion (as the gas moves up), which will reduce the gas pressure and temperature there. This expansion in volume, as gases move from bottom to up is termed as "funneling effect" here.

The advantages of this phenomena are as follows.
I) It Cools down the ionized gases thereby de-ionizing them.

II) It pushes the gases up, away from contact button region thereby minimizing the erosion there and aiding in dielectric strength build-up in contact button zone.

III) It prevents the spent gases to come back to the front end of deion plates (bottom here), once it has moved up, thereby reducing the losses occurring due to re-ignition.

IV) Additionally, because the gases are pushed up, partial arc is also in turn pushed up because of the force exerted by gases. As the partial arc moves up, its length and hence its voltage ( Arc Voltage) increases. The summation of all such partial arc voltage is the net arc voltage. So there is substantial rise in the net arc voltage also as the arc moves up. The higher arc voltage will in-turn help in quenching the arc faster.

V(L2) > V(L1) [V(L1) : arc voltage due to length L1]
for all such partial arcs=> ∑ V(L2) >> ∑ V(L1) [V(L2) : arc voltage due to length L2]

All of the aforementioned advantages will help in faster arc quenching thereby enhancing product's life and performance.

The present invention is used in two ways viz.
1. Increase the partial arc length between two deion plates, progressively as the arc moves up.
2. It creates a funneling effect (inverse tapering) for gases in the arc chutes zone which doesn't allow the ionized gases to come back and reignite.

WE CLAIM:

1. An improved arc chute assembly for use in switchgear devices, said assembly comprising:
plurality of deion plate means being operatively arranged in said arc chute assembly
wherein said plate means adapted to have non-uniform length and
wherein said plurality of plate means comprising non-uniform gaps therebetween.

2. Assembly as claimed in claim 1, wherein said plate means being arranged sequentially along a horizontal axis.

3. Assembly as claimed in claim 1, wherein said each plate means having a predetermined length.

4. Assembly as claimed in claim 1, wherein said plurality of plate means adapted to have progressively increasing length along a horizontal axis/direction.

5. Assembly as claimed in claim 1, wherein said plurality of plate means being substantially tilted with respect to each other.

6. Assembly as claimed in claim 1, wherein said gap between said plate means being more at about top portion of said plate means.

7. Assembly as claimed in claim 1, wherein said gap between said plate means being less at about bottom portion of said plate means.

8. Assembly as claimed in claim 1, wherein said plurality of plate means adapted to have progressively increasing gap along a vertical axis/direction.

9. An improved arc chute assembly for use in switchgear devices as herein substantially described and illustrated with the accompanying drawings.