Claims:1. A venting arrangement for a circuit breaker comprising:
a first baffle plate and a second baffle plate; and
at least one wire mesh and at least one perforated plate sandwiched between the first and the second baffle plates.
2. The venting arrangement of claim 1, wherein the at least one wire mesh and the at least one perforated plate are arranged alternately.
3. The venting arrangement of claim 1, wherein the venting arrangement comprises one perforated plate that is sandwiched between two wire meshes, and wherein the two wire meshes are further sandwiched between the first and the second baffle plates.
4. The venting arrangement of claim 1, wherein the venting arrangement enables reduction in ionized gas release during interruption.
5. A circuit breaker comprising a venting arrangement, said venting arrangement comprising:
a first baffle plate and a second baffle plate; and
at least one wire mesh and at least one perforated plate sandwiched between the first and the second baffle plates.
6. The circuit breaker of claim 5, wherein the at least one wire mesh and the at least one perforated plate are arranged alternately.
7. The circuit breaker of claim 5, wherein the venting arrangement comprises one perforated plate that is sandwiched between two wire meshes, and wherein the two wire meshes are further sandwiched between the first and the second baffle plates.
8. The circuit breaker of claim 5, wherein the venting arrangement enables reduction in ionized gas release during interruption.
, Description:TECHNICAL FIELD
[0001] The present disclosure relates generally to circuit breakers, and particularly to a venting arrangement for a circuit breaker.

BACKGROUND
[0002] 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] Modern process industries and power plants have an extensive electrical distribution system to provide reliable power to equipments. Nowadays, generally paralleling of transformers is done to reduce electrical losses, improve power quality, and increase reliability, which results in higher fault levels and withstand capacity (> 150 kA). Higher fault levels demand for higher interruption capacity for switching devices. During this interruption process, an arc is established between the contacts, which has to be extinguished effectively and quickly for its successful operation and protection of downstream equipments. Behavior of this arc is governed by the interaction of electric, magnetic, thermal and gas flow field. Design of venting arrangement in arc extinguishing chamber greatly influences the arc behavior. Venting arrangement in a circuit breaker has a major effect on cooling and transportation of an arc, wherein each vent pattern has its own effect on heat dissipation capability of the enclosure.
[0004] The control of exhausting gases from a circuit breaker during opening of the contacts has therefore always been a problem. This is particularly true for circuit breakers of small physical size with high interrupting ratings. But where wiring terminals are used in close proximity to the circuit breaker vents, the problem is especially acute. When an arc occurs during opening of the contacts, ionized arc gases can cause a breakdown between the terminals of the circuit breaker and any metallic enclosure within which the circuit breaker is mounted. A breakdown of this type can develop into a ground fault and, if severe enough, create a phase-to-phase fault outside of the breaker.
[0005] There is therefore a need in the art for an improved venting arrangement for modern switchgear devices for higher interruption capacity.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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 INVENTION
[0011] It is an object of the present disclosure to provide an improved venting arrangement for modern switchgear devices for higher interruption capacity.
[0012] It is an object of the present disclosure to provide a venting arrangement that is based on evaluation of the influence of pressure drop caused by a vent on the arc motion and deionization of the gases.

SUMMARY
[0013] The present disclosure relates generally to circuit breakers, and particularly to a venting arrangement for a circuit breaker.
[0014] The proposed disclosure relates to a venting arrangement for a circuit breaker comprising a first baffle plate and a second baffle plate; and at least one wire mesh and at least one perforated plate sandwiched between the first and the second baffle plates.
[0015] In an aspect, the at least one wire mesh and the at least one perforated plate can be arranged alternately. In another aspect, the venting arrangement can include one perforated plate that is sandwiched between two wire meshes, and wherein the two wire meshes are further sandwiched between the first and the second baffle plates. In another aspect, the venting arrangement enables reduction in ionized gas release during interruption.
[0016] In another aspect, the present disclosure relates to a circuit breaker that includes a venting arrangement, wherein the venting arrangement comprises a first baffle plate and a second baffle plate; and at least one wire mesh and at least one perforated plate sandwiched between the first and the second baffle plates.
[0017] 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
[0018] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0019] FIG. 1 illustrates a graph showing Deionization characteristics of a venting arrangement.
[0020] FIGs. 2A to 2C illustrate different components of the proposed venting arrangement in accordance with an embodiment of the present disclosure.
[0021] FIG. 3 illustrates a complete representation of the proposed venting arrangement in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0022] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0023] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0024] 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.
[0025] 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.
[0026] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0027] The present disclosure relates generally to circuit breakers, and particularly to a venting arrangement for a circuit breaker.
[0028] The proposed disclosure relates to a venting arrangement for a circuit breaker comprising a first baffle plate and a second baffle plate; and at least one wire mesh and at least one perforated plate sandwiched between the first and the second baffle plates.
[0029] In an aspect, the at least one wire mesh and the at least one perforated plate can be arranged alternately. In another aspect, the venting arrangement can include one perforated plate that is sandwiched between two wire meshes, and wherein the two wire meshes are further sandwiched between the first and the second baffle plates. In another aspect, the venting arrangement enables reduction in ionized gas release during interruption.
[0030] In another aspect, the present disclosure relates to a circuit breaker that includes a venting arrangement, wherein the venting arrangement comprises a first baffle plate and a second baffle plate; and at least one wire mesh and at least one perforated plate sandwiched between the first and the second baffle plates.
[0031] The proposed venting arrangement provide an arc-chute assembly that includes de-ion plates, wherein the vent and is used in circuit breaker to extinguish the arc quickly and efficiently.
[0032] As is known, vents, in switching devices, perform functions such as venting out of gases generated in arcing, filtering of metal vapors (which otherwise lead to flashover), and improving arc quenching efficiency through de-ionization of gases. A characteristic of the vent is defined by pressure loss (drop) across it, which is proportional to square of velocity through the vent and is governed by free area ratio of the vent, as is shown in FIG. 1. There are two types of pressure loss associated with vents, wherein the first one is the inertial loss due to change in velocity, and the second loss that is associated with the vent is due to friction on the hole perimeter. Loss coefficient is inversely proportional to porosity, hole Reynolds number, and hole diameter. Reynolds number corresponding to the flow can be calculated using velocity through the hole, whereas porosity is the percentage opening area of the vent. For a given hole diameter, the loss coefficient decreases when the porosity increases whereas for a given porosity, the loss coefficient decreases as the hole diameter increases. For a given porosity, when the hole diameter increases, number of holes decreases, and the total circumferential area, i.e. the equivalent wetted perimeter of the vent decreases and hence frictional loss decreases. Hence it becomes necessary to study the flow characteristics of the venting system to get desired venting through it. Flow characteristics can be derived by measuring pressure loss across the venting unit at various inlet pressures and velocities.
[0033] Pure air plasma is a mixture of 19 species (neutral, ions and electrons) of oxygen, nitrogen and combined N-O, wherein these species exists in air arc plasma with different concentration at different temperature depending on their ionization energy level. Number density and molar fraction of these species and their variation with temperature and pressure is studied to understand de-ionization phenomena. Molar fraction of ions and electrons is almost zero up to 7000 K and increases to 1 above 25000 K. It can be estimated from the graph of FIG. 1 that molar fractions of charged species are lower at low temperature and at higher pressure, hence faster heat dissipation and higher pressure inside arc chamber are desirable for de-ionization of the ionized gases coming out from the vent.
[0034] The influence of pressure drop caused by a vent on the arc motion and deionization of the gases are investigated with experimental test and numerical analysis. Experimental tests were carried out to obtain the pressure loss characteristics of different patterns of vents. Test setup was fabricated for tunnel testing and pressure drop characteristics of vents were derived at various inlet pressures. 3-Dimensional CFD simulation is performed to evaluate various parameters like exit velocity at vent, density variation and pressure characteristics of the vents.
[0035] In an aspect, with respect to FIGs. 2A-2C and FIG. 3, the proposed venting arrangement comprises a series of wire meshes 230 (also referred to as metallic grids) and perforated plates 260 that can be sandwiched between baffle plates 200, which configuration significantly reduce the ionized gas released during an interruption. In an aspect, any sequence of wire meshes 230 and perforated plates 260 can be configured based on desired pressure drop characteristics. For instance, the wire meshes 230 and the perforated plates 260 can be alternately positioned in sequence in between the baffle plates 200. In another instance, as shown in FIG. 3, the sequence can be a first baffle plate, a first wire mesh, a first perforated plate, a second wire mesh, and a second baffle plate, so as to make the venting arrangement of FIG. 3. Any other configuration is also within the scope of the present invention.
[0036] Standard arc chute designs absorb about 80% of the energy released during an interruption. The arc chutes with new design of vent i.e. grids and meshes absorb up to 90–95% of the arcing energy, considerably more than that of standard arc chutes. It is observed that the new design of vent gives very high-pressure loss, which is desirable for de-ionization of arcing gases & cooling of arc. High-pressure loss vents slows down the arc motion on de-ion plates which leads to faster cooling of the plasma column, lower exit velocities and hence effective arc quenching. Filtering of the metal vapors is more effective in this design, which reduces the flashover chances. This novel technology therefore relates to a venting arrangement that has enhanced the arc chamber performance and interruption capacity.
[0037] In an aspect, the proposed venting arrangement reduces arc flash incident energy during a bolted fault, along with reducing soot and evidence of interruption inside the equipment, which minimizes the need for cleaning and maintenance. The proposed design also minimizes the possibility of arc flashover for higher interruption capacity, along with reducing exit velocity and clearances. Furthermore, emissions during an interruption are de-ionized and cooled, making the proposed architecture more effective for higher interruption.
[0038] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0039] The present disclosure provides an improved venting arrangement for modern switchgear devices for higher interruption capacity.
[0040] The present disclosure provides a venting arrangement that is based on evaluation of the influence of pressure drop caused by a vent on the arc motion and deionization of the gases.