FIELD OF INVENTION
The present invention relates to a sealing arrangement for arc fault enclosure like switchgear. More particularly, the present invention relates to an optimized architecture of switchgear for providing sealing of door assembly (1) and side sheets of bus bar chamber and cable termination chamber for restricting the flue gases to come out of the switchgear panel.
BACKGROUND OF INVENTION
A flashover in switchgear, though rare, creates so much energy to damage man and material. It may result into severe burns or death of any personnel around. For avoiding such a scenario, sealed enclosures are very important.
However, in case of a flashover, the energy is so large that it is accompanied with force. Hence, it is also required in a switchgear panel to not allow any pressure wave go beyond the periphery of the switchgear.
Many designs employing different mechanisms have been used to address this situation. Patent Number US7871137B2 2011-01-18 Switchgear enclosure door assembly (1) seal discusses one such attempt to provide a sealed enclosure.

In figure 4, when the flow of pressures air resulting for the arc fault moves around the arrow 36, it may create distortion in Door assembly (1) 16 high enough in magnitude to allow certain portions of gases to escape through motion path 38 along the gap 35. This may be potentially damaging to the operating personnel.
To help seal this gap 35, the inventors have developed a movable seal 32D (as shown in Fig.5) that seals the door assembly (1) 16 to the face frame 28 along the hinged side 30 when an arcing event occurs.
This patent application US7871137B2 assumes the following point for the effective role of their design:
In figure 4, item 32d presses on item-28, thereby closing any space 35. It must be noted that both item 32d and 28 are metallic contact and therefore subjected to distortion. Since this member will be present all along the length of the door assembly (1), then even slight waviness in the edge of 32d or on the surface of 28, will result into a pocket from where leaking is possible.
Patent US4815237A 1989-03-28 sealing arrangement for enclosure having an access door assembly (1) discusses some other feasible options to ensure sealing of door assembly (1).

Figure 6-8 discusses the motion along which sealing can be ensured. In figure 6, door assembly (1) 14 is in open position and Gasket 40 c is in normal position. The door assembly (1) is pivot about 20 and 22. In figure 7, when the door assembly (1) is rotated in anti-clockwise, the gasket member 56 comes in contact at points 62 and 64 with the door assembly (1) member 14 which creates a sealed space. When the door assembly (1) is further pushed to its proper position, in Figure 5, it results into a proper sealing.
Patent Application US4864466A 1989-09-05 Arc-proof shield for switch gear compartment (en) discussed another novel way of shielding the 3 edges of a switchgear assembly with a rectangular door assembly (1) mounted on its face. The shield is displaced by a certain distance to cover the entire edge of the rectangular door assembly (1) therefore preventing any outward flow of gases.
This patent application presents a novel approach to secure the three sides of a metallic door assembly (1) with the help of a catch mechanism. The catches are operated about two pivots 34 and 30 (refer Figure 9). Once the Pivot (say 30) is rotated by a certain degrees, item 62 and 64 gets trapped in the catch. Similar is the arrangement in the bottom side of the door assembly (1) with Picot point 34. Also, the patent employs use of two separate independent handles to operate the two pivot points (30 and 34).

The following are the weak areas in this patent application US4864466A that we have tried to address:
1) The means to secure the door assembly (1) of the enclosure through catch and trap mechanisms on the three sides of the door assembly (1), though, is a novel way to ensure a trapped door assembly (1), yet, does not guarantee the sealed enclosure. First, since the two pivots are operable through two independent pivots, there may be a slight difference in the pressure exerted by pivots on the corresponding catch. This may result into different trapping forces with which the various catches hold the door assembly (1).
2) The catch 62, 64, 66 and 68, though cover the edge of the door assembly (1) of the switchgear panel, yet, they do not form a continuous periphery loop, thereby having voids at the corners. Being corners, they are generally the weaker areas in the door assembly (1) owing to their relative mechanical weakness in terms of strength. This may result into creation of high stress zones in the corners, and because of no continuity of sealing, might result into leak.

OBJECTS OF THE INVENTION
Therefore it is an object of the invention to propose a sealing arrangement for arc fault enclosure like switchgear which is capable of preventing the injury to the personnel because of arc fault due to extremely high pressure and thermal wave generated inside the switchgear chamber.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Fig.1 - Shows a partial view of top side of the said front door assembly (1)
of the said switchgear Panel according to the invention.
Fig.2 - Shows the U-shaped gasket support angles (2) (2a, 2b) enveloped
at the top interior edge of the said front door assembly (1) of the said switchgear Panel interfacing with member (4) (part of switchgear Panel) according to the invention.
Fig.3 - Shows a partial outward view of the said L-bend (5) on the said
bus bar chamber (7) overlapping the inner L-bend (9) on said extension chamber sheet (8) of the said switchgear panel according to the invention.

Fig.4-9- Shows a switchgear enclosure according to the prior art US 7871137B2 (Fig.4,5), US 4815237A (Fig.6-8), US 4864466A (Fig.9) respectively.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
Described herein the Fig.1, 1 is the switchgear door assembly (1) assembly in accordance with the present invention is shown. Fig.l illustrates the interior view of the said door assembly (1). As shown in Fig.l, the top, bottom, left vertical and right vertical edges of the said door assembly (1) are inwardly bend to form flanges for top (3a), bottom (3b), left vertical (3c) and right vertical (3d) of the door assembly (1). Referring to Fig.l, the door assembly (1) also includes U-shaped gasket angle (2) welded on the insides of the door assembly (1), top and bottom side of the door assembly (1) assembly with one of its edge extended (2a).
In continuation to Fig.l, the extended edge (2a) of the U-shaped gasket angle (2) welded on the inside of the door assembly (1), lands longitudinally on the

grooved volume (4a) (refer Figure 2) of the member (4) on panel, member (4) which is placed in between the side sheets of the said switchgear panel.
The said U-shaped gasket support angles (2) of the door assembly (1) go inside the panel's member (4) when the door assembly (1) is closed. Also additional pair of frame designs along the edges fastens the said door assembly (1) and the said panel. Multiple gaskets (6) are provided along all the said U-shaped gasket support angles (2) to provide proper sealing in the said switchgear panel so as to restrict the arc exhaust energy within the said switch gear panel, and is also ensured by providing appropriate sealing arrangements at all the joints of the switch gear panel.
The said U-shaped gasket support angles (2) incorporated on top side of the front door assembly (1), fixtured to the said switch gear panel in the inward position which locks in with the groove (4a) flexured on the member (4) frame of the switch gear panel in the opposite side which sets the locking position with the front door assembly (1) of the switch gear panel. The said U-shaped gasket support angles (2) incorporated at bottom side of the front door assembly (1), fixtured to the switch gear panel in the inward position grasps with the member (4) embraced to the switch gear panel at the bottom tray of the frame.

The gasket (6) fills the volume between the U-shaped gasket support angles (2) and the grooves (4a) flexured on the member (4) frame of the switch gear
panel.
The gasket (6) is mounted along the periphery of the front door assembly (1) which ensures sufficient sealing when the front door assembly (1) is closed. The U-shaped gasket support angle (2) embraced on the left and right side of the front door assembly (1) of the switch gear panel provides a similar sealing when the said front door assembly (1) closes thus preventing the release of arc fault energy from the left hand side of the door assembly (1).
The switchgear panel incorporates the bus-bar chamber (7) and the extension chamber (8). Apertures (10) at the ends where chambers partition is the major concern during arc fault. The bus bar chamber (7) and the extension chamber (8) in the switchgear panel has apertures where the chambers partition which is shielded with an extra L-bend (5) on the bus bar chamber (7) which overlaps on the L-bend (9) of rear sheet (8) of the extension chamber. In Fig.3, it refers to the overlapping of the L-bend (5), extending away from the sheet metal of the said bus bar chamber (7) with the rear side sheet L-bend (9) of the said extension chamber (8) interlocks the two components to provide absolute sealing against flue gases in case of internal arc blast.

The bus bar chamber (7), in the switchgear panel incorporates the right hand side sheet (7a) and the left hand side sheet, the sheet metal of the right hand side sheet and the left hand side sheet is flexured on all the sides extending inwardly from all the outer edges. All the flexures hold the sizing's for weldnuts, screws, washers and etc. required for affixing the other chambers of the switch gear panel.
The extension chamber (8), in the switchgear panel incorporates the right hand side sheet (8a) and the left hand side sheet, the sheet metal of the right hand side sheet and the left hand side sheet of the said extension chamber is flexured on all the sides extending inwardly from all the outer edges. All the flexures hold the sizing's for weldnuts, screws, washers and etc.
One edge (11) of the right hand side sheet (7a) of the bus bar chamber is developed with an extended edge as an extra L-bend (5) which overlaps on the L- bend (9) of rear sheet (8a) of the said extension chamber (8), thus sealing the apertures (10) in between the corresponding chambers.

WE CLAIM
1. Sealing arrangement for Arc Fault enclosures like switchgear comprising and characterized in that;
a front door assembly (1) incorporating the sheet metal flexured (3a, 3b, 3c, 3d) on all the sides extending inwardly from all the outer edges;
the said sides holding allocated U-shaped gasket support angles (2, 2);
wherein the extended edge (2a) of the U-shaped gasket angle (2) at the top of the door assembly (1) welded at the frame of the door assembly (1), lands longitudinally in the grooved volume (4a) of member (4) placed in panel;
wherein a plurality of gaskets (6) are disposed along all the said U-shaped gasket support angles (2) for providing proper sealing in the said switchgear Panel for restricting the arc exhaust energy within the said switchgear panel, wherein the bus bar chamber (7) and the extension chamber (8) of the switchgear Panel has apertures (10) where the partition of the chambers is shielded with an extra L-bend (5) on the bus bar chamber (7) overlapping on the L- bend (9) of rear sheet (8a) of the extension chamber (8).

2. Sealing arrangement for arc fault enclosure as claimed in claim 1, wherein the said gasket (6) fills in the volume between the U-shaped gasket support angles (2) and the grooves flexured on the member (4) frame of the switch gear Panel.
3. Sealing arrangement for arc fault enclosure as claimed in claim 1, wherein the L-shaped (5) angles are disposed for providing robustness of the right hand side sheet and the left hand side sheet of the bus bar chamber (7) of the switch gear Panel.