Patent Application
20120120558
The present disclosure relates to circuit breaker assemblies, and, more particularly, to circuit breaker assemblies including a chamber for cooling and collecting gas and debris produced during a circuit interruption.
Vents relieve pressure in circuit breakers generated by ionized gas produced during a circuit interruption and can be situated near grounded metal that is part of the circuit-breaker enclosure or near a line-side bus, which is at a different voltage than the exiting gas. Vents also guide the debris and gas along a path so that they can be exhausted safely away from the circuit breaker. Debris generated during the circuit interruption can include metal particles that can be made molten by hot ionized gas. When the debris exits the circuit breaker, it can reduce the dielectric strength of the vent path and the through-air and over-surface dielectric spacings to grounded metal or bussing just outside the vent and promote a ground strike or cross-phase. Conventional ways of reducing debris exiting the circuit breaker include covering the vent opening with a screen or a perforated plate. But these obstructions increase the internal pressure generated during the circuit interruption, which can be undesirable. Additionally, some circuit breaker vents allow the generated gas and debris to exit the circuit breaker which can scorch and/or discolor an interior of a circuit-breaker panel in which the circuit breaker is coupled, which can also be undesirable.
The present invention couples a chamber including one or more baffles to a housing of a circuit breaker near an exit of a vent channel of the circuit breaker to provide an additional volume and length of the vent channel for produced gas and debris to travel prior to being expelled into an electrical enclosure. Such an additional volume provides more time for the gas to cool and provides more space to trap some of the debris therein as the gas and the debris are being expelled from the circuit breaker into the enclosure, which results in less debris being expelled from the circuit breaker. The additional time for cooling the gas and debris results in the gas and debris exiting the chamber at a lower temperature than otherwise, which minimizes or reduces any discoloration and/or scorching of the paint on the inside walls of the enclosure that might otherwise occur.
The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings.
While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
The circuit breaker assembly 100 is a miniature circuit breaker (“MCB”) with an overall thickness of the housing 102 being about 1 inch or smaller, preferably about ¾ inch, an overall height, HCB, of the housing 102 being between about 2 inches and 3 inches, and an overall length, LCB, of the housing 102 being between about 3 inches and 4 inches. The chamber 170 has an overall thickness of about 1 inch or smaller, preferably about ¾ inch to match the thickness of the housing 102, an overall height, HBs, between about 1 inch and about 2 inches, and an overall length, LBS, of between about 1 inch and about 3 inches, although various other lengths and dimensions of the housing 102 and the chamber 170 are contemplated by the scope of the present disclosure.
The housing 102 has a front surface or load end 103a and a back surface or line end 103b. Current flows into the circuit breaker assembly 100 and into the stationary contact 117a via a stationary conductive blade 117. The moveable contact 118a is removably coupled to the stationary contact 117a. The moveable contact 118a is fixed to a moveable conductive blade 118. The moveable conductive blade 118 is moveable between an “on” position (as shown in
The moveable conductive blade 118 is coupled to a trip lever 150 via a spring 119. The moveable conductive blade 118 is pivotally coupled to a handle 155. The handle 155 has an “on” position (as shown in
A vent channel 104 originates in the housing 102 and extends towards the chamber 170. The circuit breaker assembly 100 includes a front pressure area 120 and a back pressure area 122. The front pressure area 120 is positioned proximate the movable contact 118a when it is disengaged from the stationary contact 117a. A gas pressure exerted upon the front pressure area 120 is greater than a gas pressure exerted upon the back pressure area 122, which is distal (farther away) from the front pressure area 120 relative to the source of the debris produced when the movable contact 118a separates from the stationary contact 117a.
The vent channel 104 allows gas and debris—produced as the moveable contact 118a is separated from the stationary contact 117a during an electrical fault—to flow from the high pressure area 120 in the housing 102, through the chamber 170, and towards an exhaust opening 172 in the chamber 170. The vent channel 104 and the chamber 170 form a path with a multitude of sections for the produced gas and debris to flow along. The path has a generally serpentine shape that forces the produced gas and debris to change flow directions at least two times before exiting the exhaust opening 172 in the chamber 170.
The chamber 170 is positioned adjacent to the front surface 103a of the housing 102. The chamber 170 can be directly or indirectly coupled to the front surface 103a of the housing 102 in a permanent or removable fashion. Alternatively, the chamber 170 can be formed as an integral portion of the housing 102 of the circuit breaker assembly 100. The chamber 170 includes two opposing walls 171a,b and five separate and spaced apart baffles 175a-e therein, although it is contemplated that the chamber 170 can include at least two separate and spaced apart baffles. Preferably, each baffle 175a-e is generally shaped as an elongated, substantially-straight finger, although various other shapes and dimensions are possible, such as, for example, an elongated, curved or wavy finger or a device (such as a plate, wall, or screen) to deflect, check, or regulate flow of a fluid, light, and/or sound.
The first, third, and fifth baffles 175a,c,e extend from a first one of the walls 171a and the second and fourth baffles 175b,d extend from a second one of the walls 171b in a staggered fashion. By “staggered fashion” it is meant that each one of the baffles 175a-e extends from a different point along the length, LBS, of the chamber 170. A length, LB, of each one of the baffles 175a-e is greater than half of a spacing distance between the two walls 171a-b. Preferably, the length, LB, of each baffle 175a-e is about two-thirds of the spacing distance between the two walls 171a,b. As such, a portion of the length, LB, of the first, third, and fifth baffles 175a,c,e partially overlaps with a portion of the length, LB, of the second and fourth baffles 175b,d. Thus, the exhausting gas and debris are forced to change directions due to the baffles 175a-e at least twice before exiting the exhaust opening 172. That is, the exhausting gas and debris must change directions to get around the baffles 175a-e in the chamber 170 of the circuit breaker assembly 100.
For example, gas and debris produced in the front pressure area 120 flow generally in a first direction indicated by arrow A towards the chamber 170, then change directions to flow around the first baffle 175a as indicated by arrow B, then change directions to flow around the second baffle 175b as indicated by arrow C, then change directions to flow around the third baffle 175c as indicated by arrow D, then change directions to flow around the fourth baffle 175d as indicated by arrow E, then change directions to flow around the fifth baffle 175b and towards the exhaust opening 172 as indicated by arrow F. In this example, the gas and debris are forced to change direction by about 180 degrees by each one of the baffles 175a-d.
Additionally, the gas and debris follow the path along a first side 176a-e of each baffle 175a-e in a first direction and then change directions to follow the path along a second opposing side 177a-d of the baffles 175a-d in a second direction that is opposite the first direction. Specifically, the gas and debris enter the chamber 170 in the direction of arrow A and flow along the first side 176a of the first baffle 175a, then change directions to flow between the second side 177a of the first baffle 175a and the first side 176b of the second baffle 175b, then change directions to flow between the second side 177b of the second baffle 175b and the first side 176c of the third baffle 175c, then change directions to flow between the second side 177c of the third baffle 175c and the first side 176d of the fourth baffle 175d, then change directions to flow between the second side 177d of the fourth baffle 175d and the first side 176e of the fifth baffle 175e towards the exhaust opening 172.
One or more optional filters 180 can be included in the chamber 170 of the circuit breaker assembly 100. The filters 180 can be loosely placed between the baffles 175a-e (as shown in
Referring to
As described above, the overall thickness, TCB, of the housing 102 is about 1 inch or smaller, preferably about ¾ inch, the overall height, HCB, of the housing 102 is between about 2 inches and 3 inches, and the overall length, LCB, of the housing 102 is between about 3 inches and 4 inches. As best seen in
A vent channel 204 originates in the housing 102 and extends towards the chamber 270. The circuit breaker assembly 200 includes a front pressure area 220 and a back pressure area 222. The vent channel 204 allows gas and debris—produced as a moveable contact 118a is separated from a stationary contact 117a during an electrical fault—to flow from the front pressure area 220 in the housing 102, through apertures 205 in the housing 102, into the chamber 270, and towards exhaust openings 272. The vent channel 204 and the chamber 270 include a multitude of sections that form a multitude of paths for the produced gas and debris to flow along.
For example, the gas and debris can initially flow from the front pressure area 220 into the chamber 270 via one of the multitude of apertures 205. From that point of entry into the chamber 270, the gas and debris can follow one of a multitude of paths from the various apertures 205 to the exhaust openings 272, such as, for example, the gas and debris can flow around, between, and/or under baffles 275a-e. However, at least one of the paths has a generally serpentine shape that causes the produced gas and debris to change flow directions at least two times before exiting the exhaust openings 272 in the chamber 270.
The housing 102 has a front surface or load end 103a, a back surface or line end 103b, a first side surface 105, and a second opposing side surface 106. The chamber 270 is positioned adjacent to the first side surface 105 of the housing 102. The chamber 270 can be directly or indirectly coupled to the first side surface 105 of the housing 102 in a permanent or removable fashion. Alternatively, the chamber 270 can be formed as an integral portion of the housing 102 of the circuit breaker assembly 200. The chamber 270 includes a top wall 271a, an opposing bottom wall 271b, two opposing side walls 271c,d, and a cover 271e that connects the walls 271a-d.
Protruding from a inside surface of the cover 271e are the five separate and spaced apart baffles 275a-e, although it is contemplated that the chamber 270 can include at least two separate and spaced apart baffles. Preferably, each baffle 275a-e is generally shaped as an elongated, substantially-straight finger, although various other shapes and dimensions are possible, such as, for example, an elongated, curved or wavy finger or a device (such as a plate, wall, or screen) to deflect, check, or regulate flow of a fluid, light, and/or sound.
The baffles 275a-e are positioned within the chamber 270 in a staggered fashion to cause the gas and debris to change flow directions at least two times before exiting the exhaust openings 272 in the chamber 270. By “staggered fashion” it is meant that each one of the baffles 275a-e extends from a different point along the length, LBS, of the chamber 270 although the baffles 275a-e are not physically attached to either of the top or the bottom walls 271a,b. Additionally, a portion of the length, LB, of the first, third, and fifth baffles 275a,c,e partially overlaps with a portion of the length, LB, of the second and fourth baffles 275b,d. Thus, the exhausting gas and debris are forced to change directions due to the baffles 275a-e at least twice before exiting the exhaust openings 272. That is, the exhausting gas and debris must change directions to get around the baffles 275a-e in the chamber 270 of the circuit breaker assembly 200.
One or more optional filters 280 can be included in the chamber 270 of the circuit breaker assembly 200. The filters 280 can be positioned within the vent channel 204, loosely placed between the baffles 275a-e (in a similar fashion as shown in
Referring to
The housing 102 has a front surface or load end 103a and a back surface or line end 103b. As shown in
A vent channel 304 is formed in the housing 102 and positioned to exhaust gas and debris—produced as a moveable contact 118a is separated from a stationary contact 117a during an electrical fault—through an aperture 107 in the housing 102, into the chamber 370, and towards an exhaust opening 372. The vent channel 304 and the chamber 370 include a multitude of sections that form a path for the produced gas and debris to flow along.
Gas and debris is exhausted via the vent channel 304 in the direction of arrow A towards the aperture 107, where the all of the gas and debris exiting the aperture 107 is received by the chamber 370. The chamber 370 redirects all of the gas and debris exiting the aperture 107 from the general direction of arrow A (a general horizontal direction) to the general direction of arrow B (a general vertical direction). Thus, gas and debris that would ordinarily be expelled directly out of the housing 102 in the general direction of arrow A towards an inside surface of a side wall of an enclosure of a load center containing the circuit breaker assembly 300 (e.g., side walls 502d,e of the enclosure 502 in
The directions of arrows A and B are offset by at least about 75 degrees from each other. Preferably, the direction of arrow B is about 90 degrees offset from the direction of arrow A. An optional filter (not shown) can be included in the chamber 370 to prevent at least some of the debris from being expelled through the exhaust opening 372.
Referring to
As described above, the overall thickness, TCB, of the housing 102 is about 1 inch or smaller, preferably about ¾ inch, the overall height, HCB, of the housing 102 is between about 2 inches and 3 inches, and the overall length, LCB, of the housing 102 is between about 3 inches and 4 inches. As best seen in
The housing 102 has a front surface or load end 103a, a back surface or line end 103b, a top surface 109, and a bottom surface 110. As shown in
A vent channel 404 originates in the housing 102 and extends towards the chamber 470. The circuit breaker assembly 400 includes a front pressure area 420 and a back pressure area 422. The vent channel 404 allows gas and debris—produced as a moveable contact 118a is separated from a stationary contact 117a during an electrical fault—to flow from the front pressure area 420, through an aperture 107 in the housing 102, into the chamber 470, and towards an exhaust opening 472. The vent channel 404 and the chamber 470 include a multitude of sections that form a path for the produced gas and debris to flow along. The path has a generally serpentine shape that forces the produced gas and debris to change flow directions at least two times before exiting the exhaust opening 472 in the chamber 470. The stationary contact 117a is attached to a stationary conductive blade 417. The stationary conductive blade 417 is similar to the stationary conductive blade 117 described above in reference to
For example, gas and debris produced in the front pressure area 420 flow generally in a first direction indicated by arrow A towards the chamber 470, then change directions to flow through the aperture 107 in the housing 102 as indicated by arrow B, then change directions to flow in a first direction indicated by arrow C, then change directions to flow in a second opposite direction as indicated by arrow D, then flow towards the exhaust opening 472 as indicated by arrow E. In this example, the gas and debris are forced to change direction by about 180 degrees by the chamber 470 before exiting the exhaust opening 472.
One or more optional filters 480 can be included in the chamber 470 and/or the vent channel 404 of the circuit breaker assembly 400. The filters 480 can be loosely placed and/or rigidly attached using one or more attachment means, such as, for example, glue, screws, staples, tape, etc. The optional one or more filters 480 can be positioned to filter the exhausting gas and debris to prevent at least some of the debris from exiting the exhaust openings 472.
Referring generally to
The load center 500 includes an electrical enclosure 502, two rows of circuit breaker assemblies 511a,b, and one of the exhaust plenums 520a,b for each of the rows of circuit breaker assemblies 511a,b therein. Each of the rows 511a,b includes a portion of the multitude of circuit breaker assemblies 510. For example, as shown, the first row 511a includes thirteen circuit breaker assemblies 510 and the second row 511b includes ten circuit breaker assemblies 510. Various numbers and arrangements of rows and circuit breaker assemblies are contemplated and possible with the exhaust plenums 520a,b of the present disclosure.
Each one of the circuit breaker assemblies 510 at least includes a trip mechanism (e.g., trip mechanism 108) to cause a moveable contact (e.g., moveable contact 118a) to separate from a stationary contact (e.g., stationary contact 117a) in response to detection by the circuit breaker assembly 510 of an electrical fault. Additionally, each one of the circuit breaker assemblies 510 includes a vent channel 512 (
Specifically, responsive to a circuit breaker assembly 510a detecting an electrical fault, gas and debris flows in the direction of arrow A along the vent channel 512 towards the exit opening 514 in the housing 102 of the circuit breaker assembly 510a, then substantially all of the gas and debris exiting the exit opening 514 flows into the exhaust plenum 520b in the direction of arrow B through an intake opening 522, which aligns with the exit openings 514 of each of the circuit breaker assemblies 510 in the second row 511b. Then, the exhaust plenum 520b redirects the gas and at least a portion of the debris that entered via the intake opening 522 in a generally horizontal direction to exit the exhaust plenum 520b via one or more exhaust openings 525 (
The exhaust plenum 520a,b can optionally include a removable filter 540 that abuts the one or more exhaust openings 525 such that at least a portion of the exiting debris is collected by the removable filter 540. The removable filter 540 can be made from a variety of materials, such as, for example, fiberglass.
The exhaust plenum 520b can optionally include a removable debris tray 530 positioned adjacent to or on top of a bottom 521 of the exhaust plenum 520b such that some of the exhausted debris is collected on the tray 530. For example, some heavier debris that might not be carried with the gas towards the exhaust openings 525 and captured/collected by the removable filter 540 can fall onto the removable debris tray 530. The debris tray 530 can be removed through slot 523 in the exhaust plenum 520a for inspection and or replacement.
As shown in
The exhaust plenum 520a,b is provided with a length, LEP, such that the exhaust plenum 520a,b is long enough to span the thicknesses, TCB, of each circuit breaker assembly 510 in an adjacent row of circuit breaker assemblies 510. For example, if a row of circuit breaker assemblies includes 10 circuit breaker assemblies, each having a thickness of 1 inch, then the exhaust plenum would at least be 10 inches long.
Each exhaust plenum 520a,b can include one or more gaskets 528 positioned between the housings of the circuit breaker assemblies 510 and the exhaust plenum 520a,b. The gaskets 528 aid in sealing the exhaust plenums 520a,b around the exit openings 514 of the circuit breaker assemblies 510 to better direct the flow of gas and debris from the vent channels 512 to the exhaust plenums 520a,b.
The exhaust plenum 520a,b includes a multitude of moveable or removable empty slot fillers 524. Each one of the empty slot fillers 524 is moved or pulled in the direction of arrow X to allow access to a corresponding portion of the intake opening 522 for each slot of the load center 500 that is fitted or filled with a circuit breaker assembly 510. The empty slot fillers 524 can be pulled upward into the position shown in
While the circuit breaker assemblies 100, 200, 300, 400, and 510 of the present disclosure are shown and described as a single pole circuit breaker assemblies, it is contemplated that the circuit breaker assemblies 100, 200, 300, 400, and 510 can be three-pole circuit breaker assemblies wherein three poles are assembled in a common circuit breaker housing. In such three-pole configurations, the three poles are interconnected with a common trip bar such that tripping one pole causes the other poles to trip. However, for ease of illustration, the present disclosure focuses on single-pole circuit breaker assemblies, although the disclosure can be applied to any number of poles in a circuit breaker assembly.
While the chamber 170 is described as being made of a molded plastic, it is contemplated that the baffles 175a-e can be made from, inter alia, a filter material (e.g., fiberglass) such that the baffles 175a-e not only act to direct flow of the gas and debris but also to filter at least some of the debris. For example, the baffles 175a-e can have a solid core made from plastic and fiberglass filter covers such that the baffles 175a-e cause the gas to change flow directions but also capture at least some of the debris.
While the baffles 275a-e are shown and described as not being physically attached to either of the walls 271a,b, it is contemplated that the first, third, and fifth baffles 275a,c,e can be physically attached to the bottom wall 271b and the second and fourth baffles 275b,d can be physically attached to the top wall 271a such that a portion of the length, LB, of the first, third, and fifth baffles 275a,c,e partially overlaps with a portion of the length, LB, of the second and fourth baffles 275b,d in the same, or similar, fashion as baffles 175a,c,e overlap with baffles 175b,d.
As described above, each of the above described chambers 170, 270, 370, 470, and 520a,b is coupled to one or more vent channels to form one or more paths, which increases the volume and length of the vent channel to provide an additional volume and length of the vent channel for produced gas and debris to travel prior to being expelled into an electrical enclosure. This additional volume and length provides additional time for the gas and debris to cool and collect within the chambers themselves and/or within one or more filters located therein, which minimizes or reduces any discoloration and/or scorching of the paint on the inside walls of the enclosure and reduces the amount of expelled debris.
Words of degree such as “substantially” or “about” are used herein in the sense of “at, or nearly at, given the process, control, and material limitations inherent in the stated circumstances” and are used herein to keep the unscrupulous infringer from taking advantage of unqualified or absolute values stated for exemplary embodiments.
While particular embodiments and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations may be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims.
