Description:

FIELD OF INVENTION
The present invention relates generally to door locking arrangements for electrical equipment such as medium voltage switchgears and, more particularly, it relates to catch based boltless door locking and sealing arrangements for a switchgear panels to withstand internal arc fault events.

BACKGROUND
The most important requirement of any switchgear is its safe operation. Medium voltage switchgear being used in supply of enormous electrical energy thus it requires much higher level of safety and reliability in operation. One of the most important consideration while designing a switchgear is prevention of occurrence of internal arc fault. Internal arc fault safety features are becoming more important in user’s specification, operation, and maintenance of a switchgear installation. An internal arc faults though rare in modern switchgear however it cannot be ruled out completely due to the reason such as failure of insulation, contact ageing, pollution, mal-operation, lack of maintenance of a switchgear and foreign body presence. The impact of such incidence may be devastating if any operating personnel is in the near vicinity.

When the fault occurs, high thermal energy is released, the temperature heats up and expands the air inside the enclosure and this can exceed the explosion limit. If the overpressure is not contained, the switchgear structure will explode and expel hot gases and particles in the surrounding atmosphere.

Switchgear can be designed in numerous ways to retain the door thereon and to resist the door from being blown open or off during an arcing fault. In the prior art, such doors typically have included bolts, pivot pins, latch teeth, threaded shaft and hole, push rod etc. around the perimeter of the door to achieve a sturdy interlock to secure the door to the panel. However, it is a challenge to have a door that can be held firmly against the frame of the panel and that will resist the high internal pressures of an arc fault.

Reference is being made to US10301849, which teaches a locking system for an enclosure, including a control bracket mounted to a door of the enclosure and configured to slide in a longitudinal direction along a guide rod running through a pin bracket of the control bracket. The control bracket further includes a latching pin to secure the door of the enclosure. A handle mechanism has a push rod that causes the control bracket to slide along the longitudinal direction, also causing the latching pin to move into a position that secures the door.

There is a need for a modified version of door locking and sealing arrangement in medium voltage switchgear which can provide higher withstand and pressure holding capacity with easier latching arrangement, thereby enhancing the safety of operating personnel.

SUMMARY
The following presents a simplified summary of the invention to provide basic understanding of some aspects of the invention, neither to identify the critical elements nor to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form, as a prelude to a more detailed description of the invention presented later.

An object of the present invention is to provide a modified version of a door locking and sealing of switchgear cubicles, which provides a higher withstand and pressure holding capacity with easier latching arrangement, thereby enhancing safety for the operating personnel.

Another object of the present invention is to provide an arrangement for complete locking and sealing of door of a medium switchgear panel with one center door handle without using number of bolts.

Yet another object of the present invention is to provide a double layered door sealing by means of gaskets which limits or eliminates the possibility of emission of hot gases and particles in the surrounding atmosphere.

Yet another object of the present invention is to provide a catch based boltless door locking and sealing arrangement which can withstand higher thermal and mechanical stress during internal arc fault.

Accordingly, an object of the present invention is to provide a system that prevents circuit breaker racking and earth switch operation unless the door of the switchgear panel is completely locked.

An aspect of the present invention is to provide a door locking and sealing arrangement for a switchgear panel, the arrangement comprising:
a door (02) swingably mounted to the Panel (01) via a hinge mechanism on one side; and
a door locking arrangement, comprising:
a center door handle (10) adapted to provide locking and unlocking by rotating in opposite directions;
wherein panel catch pin frames (07) defining the door frame at three sides in outward direction to be closed by catch plates defining door located at its three sides in inward direction;
wherein the catch plates comprising catch slots (09) adapted to receive a plurality of catch pins (08) formed on the panel catch pin frames adapted to provide locking by housing catch pins (08) with the catch slots (09);
a plurality of rotationally movable lock sockets (11, 12) on at least two corners of said catch plates adapted to rotate in particular directions in order to mechanically engage said catch pins (08) on said catch slots (09) upon rotation of center door handle (10) in a particular direction;
a gasket (13) adapted to provide a double layer door sealing when the door is closed and the door handle is moved in a particular direction.

In this arrangement the catch pin, catch plate and catch slot are operated through an easier and effortless rotary means and are arranged in such a manner to give complete locking from all the required sides of the installation keeping the construction more rigid and light weighted at the same time. This arrangement also provides a double layered door sealing by means of gaskets which limits or eliminates the possibility of emission of hot gases and particles in the surrounding atmosphere. Another safety feature offered by the invention is unless the door is completely locked circuit breaker racking and earth switch operation are not possible.

Other aspects, advantages and salient features of the invention will become apparent to those skilled in the art from the detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The above and other features, aspects, and advantages of the subject matter will be better understood with regard to the following description and accompanying drawings.
Figure 1 shows the panel (01) of present invention.
Figure 2 shows the panel (01) with door (02) in open position of present invention.
Figure 3 shows the detailed view of panel (01) with door (02) in open position of present invention.
Figure 4 shows the door (02) with door top-vertical catch (03), door bottom-vertical catch (04), door top-horizontal catch (05) and door bottom-horizontal catch (06) of present invention.
Figure 5 shows the panel structure (01) with panel catch pin frame(s) (07) of present invention.
Figure 6 shows the door top-vertical catch (03), door bottom-vertical catch (04) and panel catch pin frame(s) (07) in isometric view with the direction for locking of present invention.
Figure 7 shows the door top-vertical catch (03), door bottom-vertical catch (04) and panel catch pin frame(s) (07) in front view with the direction for locking of present invention.
Figure 8 shows the door top-vertical catch (03), door bottom-vertical catch (04) and panel catch pin frame(s) (07) in front view in locked position of present invention.
Figure 9 shows the door bottom-horizontal catch (06) and panel catch pin frame(s) (07) in isometric view in locked position of present invention.
Figure 10 shows the door top-horizontal catch (05) and panel catch pin frame(s) (07) in isometric view in locked position of present invention.
Figure 11 shows door top-vertical catch (03), door bottom-vertical catch (04) with respect to the rotation of door handle (10) in door open condition of present invention.
Figure 12 shows door top-horizontal catch (05), door bottom-horizontal catch (06) with respect to the rotation of door handle (10) in door open condition of present invention.
Figure 13 shows door top-vertical catch (03), door bottom-vertical catch (04) with respect to the rotation of door handle (10) in door close condition of present invention.
Figure 14 shows door top-horizontal catch (05), door bottom-horizontal catch (06) with respect to the rotation of door handle (10) in door close condition of present invention.
Figure 15 shows the top-corner lock socket (11) position in door open condition of present invention.
Figure 16 shows the bottom-corner lock socket (12) position in door open condition of present invention.
Figure 17 shows the door handle (10) in door open condition according to one embodiment of present invention.
Figure 18 shows the top-corner lock socket (11) position in door close condition of present invention.
Figure 19 shows the bottom-corner lock socket (12) position in door close condition of present invention.
Figure 20 shows the door handle (10) in door close condition of present invention.
Figure 21 shows the gasket (13) in door (02) in exploded front view of present invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale.

DETAILED DESCRIPTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known structure and method are omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term “comprises/comprising” if used in this specification is taken to specify the presence of stated features, integers, steps or component but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

The primary aim of the present invention is to overcome the practical limitations of using conventional latching arrangements implemented in medium voltage switchgear.

The present invention relates to a modified version of door locking and sealing of switchgear cubicles, which provides a higher pressure holding capacity with easier latching arrangement, thereby enhancing safety for the operating personnel. In the present invention complete locking and sealing of door is possible with one center door handle only which makes it different and advanced from the conventional door design where number of bolts are used for door locking and sealing purpose.

Figure 1 shows the panel (01) of present invention. Figure 2 shows the panel (01) with door (02) in open position of present invention. Figure 3 shows the detailed view of panel (01) with door (02) in open position of present invention.

Figure 4 shows the door (02) with door top-vertical catch (03), door bottom-vertical catch (04), door top-horizontal catch (05) and door bottom-horizontal catch (06) of present invention. Figure 5 shows the panel structure (01) with panel catch pin frame(s) (07) of present invention. Figure 6 shows the door top-vertical catch (03), door bottom-vertical catch (04) and panel catch pin frame(s) (07) in isometric view with the direction for locking of present invention.

Figure 7 shows the door top-vertical catch (03), door bottom-vertical catch (04) and panel catch pin frame(s) (07) in front view with the direction for locking of present invention. Figure 8 shows the door top-vertical catch (03), door bottom-vertical catch (04) and panel catch pin frame(s) (07) in front view in locked position of present invention. Figure 9 shows the door bottom-horizontal catch (06) and panel catch pin frame(s) (07) in isometric view in locked position of present invention.

Figure 10 shows the door top-horizontal catch (05) and panel catch pin frame(s) (07) in isometric view in locked position of present invention. Figure 11 shows door top-vertical catch (03), door bottom-vertical catch (04) with respect to the rotation of door handle (10) in door open condition of present invention. Figure 12 shows door top-horizontal catch (05), door bottom-horizontal catch (06) with respect to the rotation of door handle (10) in door open condition of present invention. In door open condition all four catch(s) are unlocked from catch pin(s) (08). For door opening operation, rotation of door handle (10) in anticlockwise direction will be followed by rotation of top-corner lock socket (11) and bottom-corner lock socket (12).

Figure 13 shows door top-vertical catch (03), door bottom-vertical catch (04) with respect to the rotation of door handle (10) in door close condition of present invention. Figure 14 shows door top-horizontal catch (05), door bottom-horizontal catch (06) with respect to the rotation of door handle (10) in door close condition of present invention. In door close condition all four catch(s) are locked from catch pin(s) (08). For door closing operation, rotation of top-corner lock socket (11) and bottom-corner lock socket (12) will be followed by rotation of door handle (10) in clockwise direction.

Figure 15 shows the top-corner lock socket (11) position in door open condition of present invention. It rotates 36 deg. (approx.) clockwise to move the door catch from door-open to door-close position. Figure 16 shows the bottom-corner lock socket (12) position in door open condition of present invention. It rotates 36 deg. (approx.) anti-clockwise to move the door catch from door-open to door-close position. Figure 17 shows the door handle (10) in door open condition according to one embodiment of present invention. It rotates 90 deg. clockwise to move the door catch from door-open to door-close position.

Figure 18 shows the top-corner lock socket (11) position in door close condition of present invention. It rotates 36 deg. (approx.) anti clockwise to move the door catch from door-close to door-open position. Figure 19 shows the bottom-corner lock socket (12) position in door close condition of present invention. It rotates 36 deg. (approx.) clockwise to move the door catch from door-close to door-open position. Figure 20 shows the door handle (10) in door close condition of present invention. It rotates 90 deg. anti-clockwise to move the door catch from door-close to door-open position. Figure 21 shows the gasket (13) in door (02) in exploded front view of present invention.

A door locking and sealing arrangement for a switchgear panel, the arrangement comprising: a door (02) swingably mounted to the Panel (01) via a hinge mechanism on one side; and a door locking arrangement, comprising: a center door handle (10) adapted to provide locking and unlocking by rotating in opposite directions; wherein panel catch pin frames (07) defining the door frame at three sides in outward direction to be closed by catch plates defining door located at its three sides in inward direction; wherein the catch plates comprising catch slots (09) adapted to receive a plurality of catch pins (08) formed on the panel catch pin frames adapted to provide locking by housing catch pins (08) with the catch slots (09); a plurality of rotationally movable lock sockets (11, 12) on at least two corners of said catch plates adapted to rotate in particular directions in order to mechanically engage said catch pins (08) on said catch slots (09) upon rotation of center door handle (10) in a particular direction; a gasket (13) adapted to provide a double layer door sealing when the door is closed and the door handle is moved in a particular direction.

The catch plates include door top-vertical catch (03), door bottom-vertical catch (04), door top-horizontal catch (05) and door bottom-horizontal catch (06) and the lock sockets include top-corner lock socket (11) and bottom-corner lock socket (12).

The center door handle is adapted to provide locking by rotating 90 deg. Clockwise to move the door catch (i.e., door top-vertical catch (03), door bottom-vertical catch (04), door top-horizontal catch (05) and door bottom-horizontal catch (06)) from door-open to door-close position and 90 deg. anti-clockwise to move the door catch from door-close to door-open position.

The top-corner lock socket (11) is adapted to provide locking by rotating 36 deg. (approx.) clockwise to move the door catch from door-open to door-close position and bottom-corner lock socket (12) provides locking by rotating 36 deg. (approx.) anti-clockwise to move the door catch from door-open to door-close position.

The center door handle is adapted to provide locking by rotating 90 deg. anti-clockwise to move the door catch(s) from door-close to door-open position and 90 deg. clockwise to move the door catch(s) from door-open to door-close position and the top-corner lock socket is adapted to provide locking by rotating 36 deg. (approx.) anti-clockwise to move the door catch(s) from door-close to door-open position and rotation 36 deg. (approx.) clockwise to move the door catch(s) from door-open to door-close position upon rotation of center door handle in a particular direction.

In the door open condition all the catch(s) are unlocked from catch pin(s), and in the door close condition all the catch(s) are locked from catch pin(s).

A door lock and seal arrangement for a switchgear panel adapted to provide a higher withstand and pressure holding capacity with easier latching arrangement. The enclosure accommodate catch slots formed on the catch plates present on the inside edges of the door and catch pins formed on panel catch pin frames present on the perimeters of the door frame. The door top-vertical catch, door bottom-vertical catch, door top-horizontal catch and door bottom-horizontal catch are made of metallic components, for example, mild steel or stainless steel and are meant to lock with the panel catch pin frames and the slots in door top-vertical catch, door bottom-vertical catch, door top-horizontal catch and door bottom-horizontal catch are for housing the catch pins formed on panel catch pin frames. The panel catch pin frames are also metallic component. The door cooperates with the door frame structure and locking members formed at the door to engage with each other.

Special attention is given to the design of the components which will withstand severe stresses and cannot allow any damaging effect outside. This has the advantage, that the fault in the given compartment remains confined in the place of origin. This invention describes a simpler but effective arrangement. A very compact footprint, higher reliability and safety are the basic feature of the invention. The invention which has been successfully type tested qualifies as IAC classified. Tested level of protection to the operating personal in the near vicinity of the switchgear is provided.

Some of the non-limiting advantages of the present invention are:
- Fault remains confined in the place of origin because the components are designed to withstand severe stresses and disallow any damaging effect outside. Thus, can no longer be harmful to the operating personnel that might be in the near vicinity of the switchgear.
- The arrangement does not hamper the dielectric performance of the switchgear thereby providing high voltage clearance.
- Rigid structure with light weight resulting into ease of transportation and installation.
- Ease in manufacturability of components and assembly in less time.
- Compact with respect to the space constraints offered.
- Optimized in terms of material used resulting into cost effective as well as eco-friendly product.
- Flexible/adjustable arrangement for various variants offered.
- Aesthetics and ergonomics of the structure are competent with the modern-day structure.
- Effective ability to withstand & absorb higher thermal & mechanical stress generated during internal arc fault.
- Complete isolation and ingress protection.
- Access to various parts/compartments is not compromised.
- Guaranteed spare parts availability.
- Invention is type tested as per IEC 62271-200.
- Offers highest level of operational reliability through mechanical repeatability, lesser components in linkages, minimal degradation of performance with time.
, Claims:
1. A door locking and sealing arrangement for a switchgear panel, the arrangement comprising:
a door (02) swingably mounted to the panel (01) via a hinge mechanism on one side; and
a door locking arrangement, comprising:
a center door handle (10) adapted to provide locking and unlocking by rotating in opposite directions;
wherein panel catch pin frames (07) defining the door frame at three sides in outward direction to be closed by catch plates defining door located at its three sides in inward direction;
wherein the catch plates comprising catch slots (09) adapted to receive a plurality of catch pins (08) formed on the panel catch pin frames adapted to provide locking by housing catch pins (08) with the catch slots (09);
a plurality of rotationally movable lock sockets (11, 12) on at least two corners of said catch plates adapted to rotate in particular directions in order to mechanically engage said catch pins (08) on said catch slots (09) upon rotation of center door handle (10) in a particular direction;
a gasket (13) adapted to provide a double layer door sealing when the door is closed and the door handle is moved in a particular direction.

2. The arrangement as claimed in claim 1, wherein the arrangement is for a catch based boltless door.

3. The arrangement as claimed in claim 1, wherein the catch plates include a door top-vertical catch (03), a door bottom-vertical catch (04), a door top-horizontal catch (05), a door bottom-horizontal catch (06) and the lock sockets include top-corner lock socket (11) and bottom-corner lock socket (12).

4. The arrangement as claimed in claim 1, wherein lock sockets includes a top-corner lock socket (11) and a bottom-corner lock socket (12).

5. The arrangement as claimed in claim 1, wherein the center door handle is adapted to provide locking by rotating 90 deg. anti-clockwise to move the door catch (03, 04, 05, 06) from door-close to door-open position and 90 deg. clockwise to move the door catch (03, 04, 05, 06) from door-open to door-close position.

6. The arrangement as claimed in claim 4, wherein the top-corner lock socket (11) is adapted to provide locking by rotating 36 deg (approx.) anti-clockwise to move the door catch (03, 04, 05, 06) from door-close to door-open position and rotating 36 deg. (approx.) clockwise to move the door catch (03, 04, 05, 06) from door-open to door-close position.

7. The arrangement as claimed in claim 4, wherein the bottom-corner lock socket (12) is adapted to provide locking by rotation 36 deg. (approx.) clockwise to move the door catch (03, 04, 05, 06) from door-close to door-open position and 36 deg. (approx.) anti-clockwise to move the door catch (03, 04, 05, 06) from door-open to door-close position.