CLIAMS:We Claim:
1. A vent for cooling ionized gases arising from an electric device comprising:
a first layer;
a second layer; and
a middle layer sandwiched between said first layer and said second layer, wherein said middle layer is metallic.
2. The vent of claim 1, wherein one or both of said first layer and said second layer are insulating layers.
3. The vent of claim 2, wherein said insulating layers are made of molded thermoplastic material(s).
4. The vent of claim 1, wherein one or both of said first layer and said second layer have a plurality of apertures therein to allow ionized gases to pass through to said middle layer.
5. The vent of claim 1, wherein said metallic middle layer is made of mild steel.
6. The vent of claim 1, wherein said metallic middle layer comprises a plurality of perforations.
7. The vent of claim 1, wherein said plurality of perforations are sized smaller than size of apertures configured in one or more both of said first layer and said second layer.
8. The vent of claim 1, wherein said metallic middle layer helps inefficiently pulling arc in said electric device by cooling said ionized gases and trapping arcing products.
9. The vent of claim 1, wherein said electric device is a circuit breaker.
10. An electric device operatively coupled with at least one venting assembly, said assembly comprising
a first layer;
a second layer; and
a middle layer sandwiched between said first layer and said second layer, wherein said middle layer is metallic.
11. The electric device of claim 10, wherein one or both of said first layer and said second layer are insulating layers, and wherein one or both of said first layer and said second layer have a plurality of apertures therein to allow ionized gases to pass through to said middle layer.
,TagSPECI:BACKGROUND
Field
[0001] Thepresent disclosure relates generally to circuit breakers, and, more specifically, to an efficient venting means for use in a circuit breakerduring, for instance, interruption of a fault current from circuit breaker enclosure.

Description of the Related Art
[0002] The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Switchgear and switchboard are general terms that typically cover metal enclosured switching, and interrupting devices such as fuses, circuit breakers, relays, along with associated control, instrumentation and metering devices inner connectionssuch as, bus bar, and supporting structures. Low voltage switchgear and switchboards typically operate at voltages up to about 635 volts, and with continuous currents that may exceed 5000 amperes. These low voltage switchgear and switchboards are designed to withstand short-circuit currents up to about 200,000 amperes.
[0004] Low voltage switchgear equipment typically comprises an assembly composed of multiple metal enclosed sections. Each section may have several circuit breakers stacked one above another, vertically in the front of the section, with each breaker being enclosed in its own metal compartment. Each section has a vertical or section bus that supplies current to the breakers within the section via short horizontal branch buses that extend through insulated openings in the rear wall of the breaker compartments. Vertical buses in each section are supplied with current by a horizontal main bus that runs through the line-up. Rear part of the section is typically an open area for routing of cables.Low voltage switchgear and switchboards are generally designed to withstand effects of bolted (non-arcing) faults on the load terminals, and this capability is validated during short-circuit current and short-timecurrent withstand tests.
[0005] Electrical switching apparatusesare mechanical switching devices, capable of making, carrying and breaking currents under normal circuit conditions and also making, carrying for a specified time and breaking currents under specified abnormal circuit conditions such as those of overload, short circuit, or any such abnormal circuit condition. Electrical switching apparatus such as circuit breakers are employed in diverse capacities in power distribution systems. One such application is to provide protection for electrical equipment from electrical fault conditions such as current overloads, short circuits, abnormal level voltage conditions, just to name a few.
[0006] In existing implementations, when a downstream fault such as short circuit is detected,contacts of a circuit breaker are opened.During separation of contacts, an electric arc is struck in between the contacts. At the time of short circuit when the current is high, huge amount of heat energy is generated in arc chamber in the form of arc. During this arcing period, formation of relatively high-pressure gases as well as ionization of air molecules within the arc chamber takes place. High arc temperature causes metallic and other parts to melt/evaporate/burn, therefore, these gases besides being hot contain high amount of metallic particles, which are detrimental to electrical components. Moreover, they are volatile and ignitable in nature. Higher the intensity of arc energy, higher the pressure of the molten mass generated. These high-pressure conductive gases along with molten mass within the area of arc chamber are pushed in all the directions and escapes in all possible directions depending on area available to escape. The highly volatile gases produced during arcing are needed to be exhausted from the breaker in such a way that the exhaust gases should cool properly in the shortest time possible. The circuit breakersare generally provided with vents on the front side to allow these high-pressure gases to escape. The housing and the vents of circuit breakers have to withstand high amount of pressure. In compact circuit breakers it is very difficult to locate multiple vents or vent having higher thickness. Vents having inadequate strength and experiencing such high pressure may blow out completely. In conventional arc chambers two or three separate vents are used which generally occupies more space in the circuit breaker in addition to more assembly time. The ionized arc gases may also cause a phase-to-phase electrical failure between the terminals of the circuit breaker or a phase-to-ground electrical failure with any metallic enclosure within which the circuit breaker is mounted. This is particularly true for circuit breakers of small physical size with high interrupting ratings. The problem is especially acute where wiring terminals are in close proximity to the circuit breaker vents for exhausting the gases. Accordingly, there is a need for preventing these kinds of electrical breakdowns.
[0007] In another aspect the short circuit capacity of any circuit breaker is largely governed by the performance of its arc quenching chamber, wherein the purpose of the arc quenching chamber is to resolve the problem of potential damage todown stream equipment caused due short circuit currentby quenching the arc as quickly as possible. The arc quenching chamber, as disclosed in the prior art consists of a vent system comprising multiple independent vents, which when subjected to an electric arc, release the gas and extinguish the arc. However, this process may take substantial amount of time, leading toprolonged short circuit current, which causes severe stresses on the downstream equipment due to a large amount of let-through energy. This long arcing time also results in higher erosion of contact buttons, which ultimately lowers the life of the circuit breaker. Therefore the vents in circuit breaker play an important role in improving the performance of circuit breaker by enabling quick quenching of the arc. They may to that extant determine the capacity of the circuit breaker.
[0008] Existing vent systemsalso may consist of two to three separate vents used to extinguish the electric arc, which causes the assembly to occupy plenty of space inthe circuit breaker, also leading to greater assembly time, thereby reducing productivity and increasing overall cost.
[0009] There is therefore a need for a ventilation means for an electrical switching device including, but not limited to, a circuit breaker that, apart from other advantages, assists in efficiently extinguishingthe arc.
[0010] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0011] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0012] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0013] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0014] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

OBJECTS OF THE PRESENT DISCLOSURE
[0015] It is an object of the present disclosure to provide an efficient venting means.
[0016] It is an object of the present disclosure to provide an efficient venting means for electrical switching devices such as a circuit breaker.
[0017] It is an object of the present disclosure to implement a venting means that pulls ionized arc gases towards itself for efficient cooling.
[0018] It is an object of the present disclosure to ensure that arcing products are not allowed to leave the circuit breaker, thereby causing no damage to the equipment
[0019] It is an object of the present disclosure to provide a vent that is strong and sturdy while being compact and occupy less space due to its reduced thickness.
[0020] It is an object of the present disclosure to provide a vent that can quicklyextinguish the arc, enable no/minimal stress on downstream equipment.
[0021] It is an object of the present disclosure to provide a vent that, through its efficiency, increases the life of circuit breaker.
[0022] It is an object of the present disclosure to provide a vent that is stacked into a single assembly.
[0023] It is an object of the present disclosure to provide a vent thatprevents external flashover.
[0024] It is an object of the present disclosure to provide ease of assembly thereby reducing cost and increasing productivity.
[0025] It is an object of the present disclosure to provide vents that help to design a compact circuit breaker of higher rating.
[0026] It is an object of the present disclosure to provide vent arrangement that allows the high pressure gases to pass without damaging the vent therebyreducing the stresses on housing and cover and increasing their safety margin.

SUMMARY
[0027] The present disclosure provides a venting means for an electrical device including, but not limited to, a circuit breaker, that efficiently prevents damage that may becaused to the electrical device due to an electric arc during the event of an abnormal condition such as a short circuit or current overload,to name a few. Venting means, also interchangeably referred to as “vent assembly”or “vent apparatus” or “vent” hereinafter, of the present disclosure, also considerable shortens the time for extinguishing the arc, which enables no/minimal stress on downstream equipment. Vent assembly and a method of arc venting thereof, are described herein along with potential applications of the proposed vent apparatus/assembly for optimal and safe venting of the electric arc.
[0028] In an embodiment, vent of the present disclosure can include a first end layer, a second end layer, and a middle layer sandwiched in between the first end layer and the second end layer, wherein the first end layer, the second end layer, and the middle layer form a single vent structure. Such a single vent assembly/structure occupies significantly lower space when compared with earlier known venting systems, and, being a single assembly, do not require any additional space or additional of any extra component in the electronic device in which the vent is implemented. One should appreciate that although the present disclosure has been described with reference to a circuit breaker, vent of the present disclosure can be used in any other suitable and appropriate electrical device.
[0029] In another embodiment, first end layer and second end layer, also interchangeably referred to as “front layers” or “insulating layers” hereinafter, can be made of thermoplastic material. Middle layer can be made of a suitable metallic material such as mild steel and can be sandwiched between the two front layers. Middle layer can be configured to pull the arc and instantly cool the ionized gases. In another embodiment, middle metallic layer can also be interchangeably referred to as “mesh layer” or “mesh vent layer” or “perforated layer” or “perforated sheet” hereinafter. Presence of the metallic middle layer strengthens the vent, while not increasing its thickness, and therefore not occupying more space. Insulating vents on either side provide insulation to the venting system and further enhance the venting process due to presence of three vents being formed into a single vent.
[0030] In an implementation, during arc interruption, very high pressure gets generated inside the arcing chamber, which the proposed venting apparatus efficiently handles by minimizing the stresses induced on the circuit breaker housing and cover. The presently described vent arrangement simultaneously prevents external flashover as the middle metallic of layer of vent filters the metallic content of molten gases
[0031] In another implementation, the arc is pulled towards the arc chamber through a magnetic pull, wherein the middle metallic layer helps in pulling the arc more rapidly thereby reducing the duration of short circuit current. In addition the metallic middle layer assists in quickly cooling the gases reducing their pressure. Thus the gases escaping through the vent are relatively safe for the equipment outside the electric switching device. Multilayer structure of the present venting means thus ensures that there is no damage done to the vent or the switching device thereby.
[0032] In an embodiment, a highly durable vent assembly is disclosed in the present disclosure providing greater strength, with lesser thickness, occupying same or lesser space than previous allotted for a vent as in the arrangement available in the prior art. Therefore, the aforementioned features provide for ease of assembly, reduced costs and higher overall productivity.
[0033] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Embodiments of the present disclosure are illustrated by way of examples, and not by the way of any limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:
[0035] FIG. 1 illustrates front view of the proposed venting assembly/vent in accordance with an embodiment of the present invention.
[0036] FIG. 2 illustrates an exemplary arrangement of the proposed venting assembly in accordance with an embodiment of the present invention.
[0037] FIG. 3 illustrates an exemplary configuration of the proposed vent in a circuit breaker that is configured within a circuit breaker housing in accordance with an embodiment of the present invention.
[0038] FIG. 4illustrates an exemplary view of the final circuit breaker in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION
[0039] The following discussion provides many example embodiments. Although each embodiment represents a single combination of inventive elements, the embodiments herein are considered to include all possible combinations of the disclosed elements. Thus, if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly described.
[0040] The present disclosure relates to a venting apparatus, also interchangeably referred to as a vent or venting assembly hereinafter, used for a suitable electrical switching device, preferably in low voltage systems. Although, reference to the below exemplary embodiments of the disclosure are with their application in a circuit breaker, one should appreciate that no such limitations should be drawn on the type of electric switch using the proposed venting assembly.
[0041] Embodiments of the present disclosure make use of material composition to suit the specific application being spoken of. No limitations should be drawn on the material being used if it serves the purpose of the application being spoken of herein.
[0042] FIG. 1 illustrates an exemplary overall assembly of the proposed venting apparatus 100 as visible is from the front/rear view. In an embodiment, the proposed venting apparatus comprises of at least a first insulated venting layer 102, and a second insulated venting layer (not shown as being on the rear side of the proposed apparatus), both of which sandwich there between a metallic venting layer, also interchangeably referred to as “middle layer”, “metallic layer”, “perforated layer”, “mesh layer”, among other like nomenclatures, shown partially as 104. In an embodiment, the middle layer 104 is perforated with a plurality of small apertures that allow efficient pulling of the arc and hence quenching it rapidly. The complete venting apparatus 100 acts as a single vent and hence can be configured into the circuit breaker assembly as a single piece rather than as multiple layers. In another embodiment, sandwiched metallic vent layer 104 can assist in absorbing heat from metallic globules and deionizing gases, thereby helping avoid the chances of external flashover. Thus, the present vent doesn’t need any extra space and assembling it in the breaker is also simpler. This ease of assembly reduces extra component space resulted in higher productivity and lesser cost.
[0043] Illustrated in FIG. 2 is a multilayer vent assembly 200, which can be, for instance, used in an arc-quenching chamber to extinguish the electric arc. FIG. 2 illustrates a three-layered vent comprising a first layer 202, a second layer 206, and a center/middle layer 204, wherein the middle layer 204 can be a metallic layer sandwiched between the two insulating layers 202 and 206 respectively. One should appreciate that although the present embodiment has been explained with reference to a three-layered architecture, scope of the present disclosure can include any number of layers comprising at least one metallic perforated layer. The center/middle layer 204 can be of a suitable metallic material such as, but not limited to, mild steel. Insulating layers 202/206, on the other hand, in another embodiment, be made of a suitable insulating material serving the purpose of insulating the vent.
[0044] According to one embodiment, one or both of the insulating layers 202/206 can include a plurality of apertures 210 of relatively larger dimensions when compared with the apertures 208/mesh-like structure of the middle layer 204. One of the purposes of these apertures 210 is primarily to vent out gases at high pressure, which are magnetically pulled towards the metallic layer 204.Cooled ionized gases can then be vented through the venting apertures 208 of the metallic vent layer 204 and finally exhausted through the venting apertures 210 of the second insulating vent layer. According to one embodiment, aperture size 208 of the metallic vent 204 is comparatively much smaller than the apertures 210 of the insulating layer 202 and 206, wherein the center metallic layer 204 with multiple small apertures 208 provides for efficient and rapid pulling of the ionized and gases and also efficient and rapid cooling of the highly volatile ionized gases produced during arcing.
[0045] Person of ordinary skill in the art can appreciate that size and shape of an aperture of the metallic and insulating vents may vary in accordance with specific requirements as long as functions of the components serve their purpose despite the variations in size and shape of apertures. Therefore, no limitations are drawn on that aspect herewith. Further, the specific materials used to manufacture the vent layers may vary as long as the functions of the vent layers serve their desired purpose.
[0046] According to one embodiment, in a circuit breaker, during an event of abnormal condition, two contacts separate when the protection release system senses an abnormal condition and reacts to overcome it. An electric arc is struck in between the contacts. The arc is then moved towards the arc quenching mechanism, which consists of an arc chute where it splits into several series of small arcs and cools down, raising the arc voltage and thus quenching the arc. During this arcing period, dielectric strength of the air breaks down substantially to a lower value. Formation of relatively high pressure gases as well as ionization of air molecules within the arc chamber takes place. These gases are hot and contain high amount of metallic particles, which are deleterious to electrical components. Moreover, they are volatile and ignitable in nature. Therefore, these gases are to be kept separated until ionization has dissipated and the temperature of these gases has moderated. In such a scenario, the sandwiched metallic vent 204 assists in magnetically pulling the electric arc, absorbing heat from metallic globules, and de-ionizing the gases, thereby avoiding the chances of external flashover.
[0047] According to one embodiment, at the time of short circuit, huge amount of heat energy is generated in an arc chamber in the form of an electric arc. The circuit breaker arc chamber is designed in such a way that the arc is magnetically pulled in the forward direction. While the arc is pulled in the forward direction, the arc produces molten mass, and metal vapors are formed. Pressure of the molten mass depends on the intensity of arc energy. These high-pressure conductive gases along with molten mass within the area of arc chamber tend to be pushed in all directions. The high-pressure gas and molten mass tend to escape in all the possible directions depending on the area available to escape. Therefore, the circuit breaker is provided with a multilayer vent 200, where the central metallic vent layer 204 assists in pulling the arc towards it, thereby concentrating the arc in a single direction and venting it out to safety once the arc is cooled in the shortest possible time.
[0048] FIG. 3 illustrates an exemplary housing structure/arrangement/configuration/construction 300in accordance with embodiment of the present disclosure. In an embodiment, housing 300 comprises of vent assembly 302 fitted into a case 306 of circuit breaker coupled with an arc chamber having capacity to withstand high amount of pressure in order to avoid breakage of vent and creating a hazardous situation due to an electric failure. Vent assembly 302 of the present disclosure is extremely sturdy and durable, owing to the multiple layers that constitute the vent, wherein the contribution of properties owing to strength of the vent 302/200can be attributed to the metallic layer 204. The multilayer aspect of the vent 302/200 can also provide for a vent with lesser thickness, thereby providing a compact vent with a high degree of strength and sturdiness.
[0049] According to one embodiment, venting assembly 302 can be placed in an allocated slot 308 of a moulded case circuit breaker assembly 306. The circuit breaker case 306 can be provided in a protective circuit breaker housing 304, covering the circuit breaker from either side, and leaving the front end and back end open to allow the exhaust gases to enter and exit through the vent assembly 302.
[0050] One should appreciate that circuit breaker assembly may not be changed in any way in comparison to the one being used in the prior art, to accommodate the proposed vent assembly 302. Therefore, despite being multi-layered, thickness of the vent assembly 302 remains same or lesser when compared with the venting structures being used in the prior art, allowing the vent 302 to be conveniently accommodated in the slot 308 provided. Hence, use of a metallic layer 204 in the vent assembly 302 helps to strengthen the vent with lesser thickness based on available space to get better performance as desired. According to one embodiment, replacement of two or three vents with a single vent results in better utilization of space. Considering that vent 302 does not require any additional space and assembling it in the circuit breaker is also simpler, this ease of assembly reduces extra component space resulting in higher productivity and lesser cost.
[0051] It must be appreciated that as evident from FIG. 3, housing 304 can have higher thickness than the vent 302, further illustrating the significance of metallic layer 204 in the vent 302 to provide high strength with lesser thickness in order to withstand high pressure stresses generated due to arcing.
[0052] FIG. 4 illustrates an exemplary final assembly of proposed circuit breaker assembly 400, wherein the circuit breaker assembly 400 comprises of a plurality of arc chambers 406, housing 408, circuit breaker assembly cover 402, and one or more vents 404(a), 404(b), 404(c), …, 404(n), collectively referred to as vents 404 hereinafter. Any other number of rows of vents (not shown in figure) can be incorporated behind or in any other arrangement. It must be further appreciated that based on the intensity of electric application being used, the circuit breaker assembly 400 can be designed to incorporate any number of rows and columns of vents, and no limitation is drawn on the same.
[0053] According to one embodiment, housing 408, cover 402, and arc chamber(s) 406 of the circuit breaker assembly 400 can include an insulating and mouldable substance such as a polymeric substance in order to be able to withstand inherent heat produced by arcing gases, and to ensure complete insulation and safety of the circuit breaker.
[0054] Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, the feature(s) of one drawing may be combined with any or all of the features in any of the other drawings. The words “including”, “comprising”, “having”, and “with” as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed herein are not to be interpreted as the only possible embodiments. Rather, modifications and other embodiments are intended to be included within the scope of the appended claims.