Arc extinguishing device and molded case circuit breaker

Abstract

The application belongs to the field of molded case circuit breakers, and particularly relates to a flying arc eliminating device and a molded case circuit breaker. The flying arc eliminating device comprises a cover body, at least one exhaust passage is arranged in the cover body, the exhaust passage has an air inlet and an air outlet, at least one arc extinguishing plate is arranged in the exhaust passage, and the exhaust passage has at least one bend between the air inlet and the air outlet. Since at least one bend is arranged in the exhaust passage, the length of the exhaust passage can be increased without being limited by the size of the flying arc eliminating device, and the effect of eliminating flying arc can be improved.

Description

Technical Field

[0001] This invention belongs to the field of molded case circuit breakers, specifically relating to an arc-extinguishing device and a molded case circuit breaker. Background Technology

[0002] The issue of arcing safety in the molded case circuit breaker industry has always been a major concern. When the short circuit protection of molded case circuit breakers on the market is interrupted, arcing sparks often fly everywhere, posing a significant safety hazard. This is because there is no arcing venting channel or the arcing venting channel is very short, resulting in large arcing sparks being generated outside the circuit breaker. In the prior art, to solve the problem of arcing, there are devices for eliminating arcing at the arcing point outside the circuit breaker, such as those disclosed in Chinese patents CN202120649600.6, CN202223464249.7, CN201620915493.6, and CN201520904965.3. These generally include a cover connected to the circuit breaker housing and several arc-extinguishing plates fixed inside the cover. The cover increases the channel for arc venting, and the arc-extinguishing plates divide and cool the arc layer by layer to extinguish it. However, in practice, due to the limitation of installation space, the length of the cover is insufficient and cannot be further increased. Therefore, the effect of extinguishing the arc needs to be improved. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide an arc-extinguishing device and a molded case circuit breaker.

[0004] The technical solution adopted by the present invention is as follows: an arc extinguishing device includes a cover, the cover having at least one exhaust channel, the exhaust channel having an air inlet and an air outlet, the exhaust channel having at least one arc extinguishing plate, and the exhaust channel having at least one bend between the air inlet and the air outlet.

[0005] The exhaust channel has at least one Venturi structural unit, which has an inlet section with a flow cross-sectional area of ​​S1, a throat section with a flow cross-sectional area of ​​S2, and a diffuser section with a flow cross-sectional area of ​​S3, wherein S1 is greater than S2 and S3 is greater than S2.

[0006] The bend is connected to a first transition channel at its front end and a second transition channel at its rear end. The cross-sectional area of ​​the flow at the rear end of the first transition channel is greater than or equal to the cross-sectional area of ​​the flow at the front end of the bend it is connected to. The cross-sectional area of ​​the flow at the front end of the second transition channel is greater than or equal to the cross-sectional area of ​​the flow at the rear end of the bend it is connected to. The first transition channel, the bend, and the second transition channel, which are connected sequentially along the fluid flow direction, constitute a Venturi structural unit. The bend is the throat segment of the Venturi structural unit.

[0007] The exhaust channel has at least two bends. Among two adjacent bends, the second transition channel connected to the bend in front simultaneously constitutes the first transition channel connected to the bend in the rear. The cross-sectional area of ​​the front end of the second transition channel is larger than the cross-sectional area of ​​the rear end of the bend it connects to.

[0008] Both the first transition channel and the second transition channel are funnel-shaped channels with a front flow cross-sectional area larger than the rear flow cross-sectional area. The flow cross-sectional area at the rear end of the first transition channel is equal to the flow cross-sectional area at the front end of the bend it connects to. The part where the first transition channel connects to the bend has a smooth inner wall. The front end of the second transition channel forms a sufficiently widened groove on one or both sides of the end of the bend.

[0009] The arc-extinguishing plate is fixed in the middle of the second transition channel, and several arc-extinguishing plates are provided between the bend at the last end and the air outlet.

[0010] The cover body is provided with at least one second mounting cavity, and a channel forming block is fixed in the second mounting cavity. A flow channel groove is opened on one or both sides of the channel forming block. The flow channel groove on the side of the channel forming block cooperates with the inner wall of the second mounting cavity or the inner wall of the second mounting cavity and the inner wall of the circuit breaker housing to form an exhaust channel. The cover body is provided with a first opening and a second opening respectively for the air inlet and air outlet of the exhaust channel. The arc extinguishing plate is fixed in the flow channel groove.

[0011] The cover is provided with a second mounting port for inserting the channel forming block into the second mounting cavity.

[0012] A molded case circuit breaker includes a circuit breaker body, the circuit breaker body including a circuit breaker housing and a contact system, an operating mechanism, an arc extinguishing system, and an overload protection system located within the circuit breaker housing. The circuit breaker housing has an arc extinguishing outlet corresponding to the arc extinguishing system's arc exit end. The circuit breaker body is characterized by further including an arc extinguishing device as described above, the air inlet of which is connected to the arc extinguishing outlet of the circuit breaker housing for collecting the gas discharged from the circuit breaker body.

[0013] The circuit breaker housing forms an arc-extinguishing outlet above the arc-extinguishing system and at the tail of the arc-extinguishing system, and the arc-extinguishing device is connected above the base and to the side of the top cover.

[0014] The beneficial effects of the present invention are as follows: Since the present invention provides at least one bend in the exhaust channel, the length of the exhaust channel can be increased without being limited by the size of the arc elimination device, thereby increasing the effect of eliminating arc. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0016] Figure 1 This is a schematic diagram of the structure of a molded case circuit breaker according to an embodiment of the present invention; Figure 2 This is an exploded view of a molded case circuit breaker according to an embodiment of the present invention; Figure 3 This is a cross-sectional view of a molded case circuit breaker according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the circuit breaker body in one embodiment of the present invention; Figure 5 This is an exploded view of the circuit breaker body in one embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the upper cover in one embodiment of the present invention; Figure 7 This is a schematic diagram of the base structure in one embodiment of the present invention; Figure 8 This is a cross-sectional view of an arc-eliminating device in one embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of the cover in one embodiment of the present invention; Figure 10 This is a schematic diagram of the structure of a channel forming block equipped with an arc extinguishing plate in one embodiment of the present invention; Figure 11 This is a side view of a channel forming block in one embodiment of the present invention; Figure 12 This is a schematic diagram of the arc-extinguishing plate in one embodiment of the present invention; In the picture, Circuit breaker body - 100, circuit breaker housing - 110, base - 111, first connecting plate - 1111, first limiting slot - 1112, limiting step - 1113, top cover - 112, second connecting plate - 1121, second limiting block - 1122, first vertical partition - 113, second vertical partition - 114, arc extinguishing outlet - 115, first wiring support - 116, second wiring support - 117, contact system - 120, moving contact - 121, stationary contact - 122, first conductive connector - 123, second conductive connector - 124, operating mechanism - 130, operating handle - 131, arc extinguishing system - 140; Arc extinguishing device-200, exhaust channel-210, air inlet-211, air outlet-212, bend-213, widened groove-214, channel forming block-220, flow channel groove-221, arc extinguishing plate slot-222, arc extinguishing plate-231, small hole-232, cover-240, second mounting cavity-241, first opening-242, second opening-243, first connecting platform-244, second connecting platform-245, partition-246, first limiting insert-247, first side plate-248, second limiting slot-249; Terminal block extension plate-300. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0018] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0019] The directional and positional terms used in this invention, such as "up," "down," "front," "back," "left," "right," "inner," "outer," "top," "bottom," and "side," are merely for reference to the accompanying drawings. Therefore, the directional and positional terms used are for illustrating and understanding this invention, and not for limiting the scope of protection of this invention.

[0020] In this invention, the terms "front" and "rear" in relation to "exhaust passage" refer to "front" and "rear" along the direction of fluid flow within the exhaust passage.

[0021] A type of molded case circuit breaker, such as Figure 1-3 As shown, it includes a circuit breaker body 100, an arc extinguishing device 200, and a terminal block extension plate 300.

[0022] like Figure 3-5 As shown, the circuit breaker body 100 includes a circuit breaker housing 110, a contact system 120, an operating mechanism 130, an arc extinguishing system 140, and an overload protection system.

[0023] The circuit breaker housing 110 includes a base 111 and a top cover 112. The base 111 has a first mounting cavity and a first mounting port at its upper end. The circuit breaker housing 110, contact system 120, operating mechanism 130, arc extinguishing system 140, and overload protection system are all installed in the first mounting cavity. The top cover 112 is connected to the first mounting port at the upper end of the base 111.

[0024] The contact system 120 includes a moving contact 121, a stationary contact 122, a first conductive connector 123 electrically connected to the moving contact 121, and a second conductive connector 124 electrically connected to the stationary contact 122. The first conductive connector 123 and the second conductive connector 124 pass through the circuit breaker housing 110, and the circuit breaker housing 110 is provided with a first wiring support 116 and a second wiring support 117 on the outside of the circuit breaker housing 110 corresponding to the first conductive connector 123 and the second conductive connector 124, respectively. Specifically, the first wiring support 116 and the second wiring support 117 are disposed at both ends of the base 111. The base 111 is provided with a first vertical partition 113 inserted between the first wiring support 116 and the first mounting port, and a second vertical partition 114 inserted between the second wiring support 117 and the first mounting port. The first conductive connector 123 and the second conductive connector 124 are installed onto the first wiring support 116 and the second wiring support 117 through the first mounting port. Then, the first vertical partition 113 and the second vertical partition 114 are inserted above the first conductive connector 123 and the second conductive connector 124 to separate the inside and outside, which facilitates installation and ensures electrical safety.

[0025] The operating mechanism 130 is connected to the moving contact 121 and is used to drive the moving contact 121 to rotate, thereby opening and closing with the stationary contact 122. The device driving the operating mechanism 130 can be a manual drive mechanism and / or an automatic drive mechanism. A common manual drive mechanism is the operating handle 131 shown in the figure, and a common automatic drive mechanism can be a drive motor triggered by a control signal.

[0026] The arc extinguishing system 140 includes an arc extinguishing cover and a plurality of arc extinguishing grids disposed inside the arc extinguishing cover. The arc extinguishing cover has an arc inlet end and an arc outlet end. The arc inlet end is disposed above the stationary contact 122, corresponding to the arc breaking path of the moving contact 121. The circuit breaker housing 110 has an arc discharge outlet 115 corresponding to the arc outlet end.

[0027] The overload protection system works in conjunction with the operating mechanism 130 to drive the operating mechanism 130 to freely trip and cause the moving contact 121 to rotate and open the circuit when a circuit fault occurs.

[0028] The arc extinguishing device 200 is connected to the circuit breaker housing 110. The arc extinguishing device 200 is provided with at least one exhaust channel 210. The exhaust channel 210 has an air inlet 211 and an air outlet 212. The air inlet 211 is connected to the arc extinguishing outlet 115 of the circuit breaker housing 110 and is used to collect the gas discharged from the circuit breaker body 100. The gas may contain arcs. The exhaust channel 210 has at least one bend 213 and is provided with at least one arc extinguishing plate 231. The air outlet 212 is connected to the outside and is used to discharge gas. The gas discharged from the circuit breaker body 100 passes through the exhaust channel 210. Since the exhaust channel 210 is provided with at least one bend 213, the length of the exhaust channel 210 is not limited to the size of the arc extinguishing device 200 and can be increased, which can greatly increase the effect of extinguishing arcs.

[0029] Furthermore, at least one upward air guiding channel unit with an upward air guiding tendency and at least one downward air guiding channel unit with a downward air guiding tendency are provided between the air inlet 211 and the air outlet 212, and at least one lateral air guiding channel unit with a leftward or rightward air guiding tendency is provided.

[0030] The air inlet 211 is connected to the upward air guiding channel unit, the air outlet 212 is connected to the downward air guiding channel unit, and the arc extinguishing plate is fixed in the middle position of the upward air guiding channel unit, the downward air guiding channel unit, or the horizontal air guiding channel unit.

[0031] Furthermore, the exhaust channel 210 has at least one Venturi structural unit, which has an inlet section with a flow cross-sectional area of ​​S1, a throat section with a flow cross-sectional area of ​​S2, and a diffuser section with a flow cross-sectional area of ​​S3, where S1 is greater than S2 and S3 is greater than S2. The Venturi structural unit is based on the Venturi effect, where the dynamic pressure (velocity head) reaches its maximum and the static pressure (resting pressure) reaches its minimum at the narrowest point of the Venturi structural unit's channel. The fluid velocity increases due to the reduction in the flow cross-sectional area. The entire flow undergoes the channel narrowing process simultaneously, thus the pressure also decreases at the same time, generating a pressure difference to improve the flow performance of the airflow in the exhaust channel.

[0032] Furthermore, the front end of the bend 213 is connected to a first transition channel and the rear end of the bend 213 is connected to a second transition channel. The cross-sectional area of ​​the rear end of the first transition channel is greater than or equal to the cross-sectional area of ​​the front end of the bend 213 to which it is connected. The cross-sectional area of ​​the front end of the second transition channel is greater than or equal to the cross-sectional area of ​​the rear end of the bend 213 to which it is connected. The first transition channel, the bend 213, and the second transition channel, which are connected sequentially along the fluid flow direction, constitute a Venturi structural unit. In this Venturi structural unit, the bend 213 constitutes a throat section with a cross-sectional area of ​​S2, and the first transition channel and the second transition channel constitute an inlet section and a diffuser section, respectively.

[0033] Furthermore, both the first and second transition channels are funnel-shaped channels with a front-end flow cross-sectional area larger than the rear-end flow cross-sectional area. The flow cross-sectional area at the rear end of the first transition channel is equal to the flow cross-sectional area at the front end of the bend 213 it connects to, and the connection between the first transition channel and the bend 213 has a smooth inner wall. This avoids creating greater resistance to the airflow.

[0034] Furthermore, the exhaust passage 210 has at least two bends 213. Among two adjacent bends 213, the second transition passage connected to the forward bend 213 simultaneously constitutes the first transition passage connected to the rearward bend 213. The cross-sectional area of ​​the front end of the second transition passage is larger than the cross-sectional area of ​​the rear end of the bend 213 it connects to. This prevents the flow area of ​​the exhaust passage 210 from becoming smaller and smaller.

[0035] Furthermore, the front end of the second transition channel forms a widened groove 214 on one or both sides of the end of the bend 213. By setting the widened groove 214, the cross-sectional area of ​​the flow at the front end of the second transition channel is suddenly increased without creating resistance to the fluid.

[0036] The arc-extinguishing plate 231 is fixed in the middle of the second transition channel, specifically between the front and rear ends of the second transition channel. An arc-extinguishing plate 231 is provided between adjacent bends 213, while several arc-extinguishing plates 231 are provided between the final bend 213 and the outlet 212. This arrangement ensures complete elimination of arcing before the gas exits from the outlet 212. Specifically, five arc-extinguishing plates 231 are provided at a certain distance between the final bend 213 and the outlet 212.

[0037] Specifically, the arc-extinguishing device 200 includes a cover 240 and a channel forming block 220, such as... Figure 9As shown, the cover 240 has at least one second mounting cavity 241 and a second mounting port at its lower end; the channel forming block 220 is adapted to the shape of the second mounting cavity 241 and fixed in the second mounting cavity 241; a flow channel groove 221 is opened on one or both sides of the channel forming block 220; the flow channel groove 221 on the side of the channel forming block 220 cooperates with the inner wall of the second mounting cavity 241 or the inner wall of the second mounting cavity 241 and the inner wall of the circuit breaker housing 110 to form an exhaust channel 210; the cover 240 has a first opening 242 and a second opening 243 corresponding to the air inlet 211 and the air outlet 212 of the exhaust channel 210, respectively. In this embodiment, the flow channel groove 221 of the channel forming block 220 is partially exposed outside the cover 240. This part is inserted into the circuit breaker housing 110 when the arc extinguishing device 200 is connected to the circuit breaker body 100, so that none of the channel forming blocks 220 are exposed outside the cover 240 and the corresponding flow channel groove 221 mates with the inner wall of the circuit breaker housing 110. The channel forming block 220 is inserted into the second mounting cavity 241 through the second mounting port. The channel forming block 220 with a suitable flow channel groove 221 can be selected as needed.

[0038] The arc-extinguishing plate 231 is fixed within the flow channel groove 221 of the channel forming block 220. Specifically, as shown... Figure 11 As shown, at least one set of arc extinguishing plate slots 222 are provided on the side walls of the flow channel groove 221 for inserting and installing the arc extinguishing plate 231. The arc extinguishing plate 231 is fixed in the flow channel groove 221 by insertion.

[0039] The structure of the arc-extinguishing plate 231 is as follows: Figure 12 As shown, there are several small holes 232 distributed thereon, which have the effect of segmenting and cooling the flying arc.

[0040] like Figure 4 As shown, the length of the base 111 is greater than the length of the top cover 112, so that the circuit breaker housing 110 forms an arc extinguishing outlet 115 above the arc extinguishing system 140 and at the tail of the arc extinguishing system 140. The arc extinguishing device 200 is connected above the base 111 and to the side of the top cover 112.

[0041] The circuit breaker body is provided with a rotatable operating handle. The operating handle has a swing path that swings to drive the operating mechanism. The operating handle has a step and a rotating handle protruding from the surface of the step to form an operating mechanism. The highest point of the step surface is displaced as the operating handle swings. The rotating handle protrudes from the step, and the top of the rotating handle is the top of the operating handle. The height H1 of the top surface of the arc-extinguishing device relative to the highest point of the movement trajectory of the step position of the operating handle is matched with the height H2 of the highest point of the top movement trajectory of the operating handle relative to the highest point of the movement trajectory of the step position of the operating handle.

[0042] Preferably, the range of H1 is 0.1*H2~3*H2, so that the top surface 2A of the arc eliminator is slightly higher than the top surface 1A of the step or the top surface of the circuit breaker body.

[0043] As the optimal choice, H1 is 1*H2. Considering the error, the range of H1 is limited to 0.95*H2~1.05*H2, so as to meet the installation requirements of the arc extinguishing device without increasing the installation space height of the circuit breaker, and to achieve product miniaturization while realizing the extension of the air passage.

[0044] In conjunction with the above structure, the height of the highest point of the exhaust channel is set higher than the top surface 1A of the step or the top surface of the circuit breaker body, so as to make full use of the height space of the arc extinguishing device to extend the exhaust channel.

[0045] The circuit breaker housing 110 is provided with an arc extinguishing outlet 115 corresponding to the position of the arc extinguishing system 140. The arc extinguishing device 200 is connected above the base 111 and to the side of the top cover 112. The outer side of the arc extinguishing device 200 protrudes from the first mounting surface on the side of the circuit breaker body 100. The first mounting surface is provided with a wiring position for connecting external lines. The bottom surface of the arc extinguishing device is higher than the wiring position, so that a wiring operation space is formed between the bottom surface of the arc extinguishing device and the first mounting surface.

[0046] Since the circuit breaker body 100 is provided with an arc extinguishing system 140 near the first mounting surface, and the arc extinguishing device 200 is provided with an arc-emission space inside, the circuit breaker body 100 is provided with an arc-discharging outlet 115 for connecting the arc extinguishing system 140 and the arc-emission space. The arc extinguishing device 200 has an insulated arc-emission device bottom surface, so that the arc-emission space is electrically isolated from the wiring operation space through the arc-emission device bottom surface.

[0047] Furthermore, the side of the arc extinguishing device away from the circuit breaker body is the outer side of the extinguishing device, and the position of the outer side of the extinguishing device in the lateral direction does not exceed the position of the outer end of the terminal extension plate; the outer end of the terminal extension plate refers to the end of it away from the circuit breaker body.

[0048] The cover 240 of the arc extinguishing device 200 is fixed to the circuit breaker housing 110 by threaded fasteners.

[0049] Specifically, the base 111 has a second wiring support 117 at one end protruding relative to the upper cover 112 to form at least two first connecting plates 1111, and the second wiring support 117 is disposed between two adjacent first connecting plates 1111; the upper cover 112 protrudes at one end near the second wiring support 117 to form at least two second connecting plates 1121, and an L-shaped opening structure arc discharge outlet 115 is formed between two adjacent second connecting plates 1121, such as... Figure 9 As shown, the cover 240 is provided with a first connecting platform 244 for fitting and connecting with the upper end face of the first connecting plate 1111, and a second connecting platform 245 for fitting and connecting with the upper end face of the second connecting plate 1121. Threaded fasteners connecting the cover 240 and the circuit breaker housing 110 are provided between the first connecting platform 244 and the first connecting plate 1111, and between the second connecting platform 245 and the second connecting plate 1121.

[0050] The base 111 is provided with at least two second wiring support seats 117 and at least three first connecting plates 1111. The outer wall of the first connecting plate 1111 between two adjacent second wiring support seats 117 is provided with a first limiting slot 1112, which is larger on the inside and smaller on the outside, arranged vertically. The cover 240 is provided with a number of second mounting cavities 241 equal to the number of second wiring support seats 117 and a number of first connecting platforms 244 equal to the number of first connecting plates 1111. The second mounting cavities 241 are located between adjacent first connecting platforms 244, and the first connecting platforms 244 between adjacent second mounting cavities 241 protrude downwards to form partitions 246. The partitions 246 are provided with first limiting blocks 247 that engage with the first limiting slots 1112 for limiting insertion. The partitions 246 can separate adjacent wiring cavities, improving electrical safety. Simultaneously, the first limiting blocks 247 engaging with the first limiting slots 1112 facilitate installation.

[0051] The cover 240 has a first side plate 248 at the outer end of the second connecting platform 245 away from the first connecting platform 244. The lower end face of the first side plate 248 is in contact with the upper end face of the upper cover 112, and the lower end face of the first side plate 248 is provided with a second limiting slot 249. The upper end face of the upper cover 112 is provided with a second limiting plug 1122 that is limited and inserted into the second limiting slot 249.

[0052] The inner wall of the first connecting plate 1111 is provided with a limiting step 1113. The channel forming block 220 is inserted between two adjacent first connecting plates 1111 and its lower end abuts against the limiting step 1113 for limiting cooperation.

[0053] The bottom of the air inlet 211 is not lower than the upper end of the second vertical partition 114. With this configuration, a wiring space for wiring the second conductive connector 124 is formed between the bottom of the channel forming block 220 and the outer wall of the second vertical partition 114, and the exhaust channel is completely separated from the wiring terminal, which effectively ensures safety.

[0054] The terminal extension plate 300 is disposed and connected to the second conductive connector 124. The outer end of the terminal extension plate 300 protrudes relative to the outer end of the arc-extinguishing device 200, which facilitates wiring. Specifically, the terminal extension plate 300 and the second conductive connector 124 are detachably bolted together, and different wiring structures can be selected for the terminal extension plate 300 as needed.

[0055] By utilizing the space above and at the tail of the arc-extinguishing system 140, and by adding a certain length next to the second conductive connector 124, an arc-extinguishing device 200 is formed. Through the placement of the bend 213 and a reasonable spatial layout, the length of the exhaust channel 210 in the arc-extinguishing device 200 can be significantly increased. Figure 3 , Figure 8 Taking the structure shown as an example, the arc extinguishing device 200 occupies 40mm of space next to the second conductive connector 124, and the upper height of the arc extinguishing device 200 is not significantly higher than the height of the operating handle 131 shown in the figure. In the limited space, by using the setting of six bends 213, the space is fully utilized, and the exhaust channel formed can be increased to 310mm, which is equivalent to the channel length being increased by more than 7 times, and the effect is very obvious.

[0056] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. An arc-extinguishing device, comprising a housing (240), wherein the housing (240) has at least one exhaust channel (210), the exhaust channel (210) having an air inlet (211) and an air outlet (212), and at least one arc-extinguishing plate is provided in the exhaust channel (210), characterized in that: The exhaust passage (210) has at least one bend (213) between the air inlet (211) and the air outlet (212). The exhaust channel (210) has at least one Venturi structural unit, which has an inlet section with a flow cross-sectional area of ​​S1, a throat section with a flow cross-sectional area of ​​S2, and a diffuser section with a flow cross-sectional area of ​​S3, wherein S1 is greater than S2 and S3 is greater than S2. The front end of the bend (213) is connected to a first transition channel and the rear end of the bend (213) is connected to a second transition channel. The cross-sectional area of ​​the flow at the rear end of the first transition channel is greater than or equal to the cross-sectional area of ​​the flow at the front end of the bend (213) to which it is connected. The cross-sectional area of ​​the flow at the front end of the second transition channel is greater than or equal to the cross-sectional area of ​​the flow at the rear end of the bend (213) to which it is connected. The first transition channel, the bend (213) and the second transition channel connected in sequence along the fluid flow direction constitute a Venturi structural unit. The bend (213) is the throat section of the Venturi structural unit. The arc-extinguishing plate is fixed in the middle of the second transition channel, and several arc-extinguishing plates (231) are provided between the bend (213) at the last end and the air outlet (212).

2. The arc-eliminating device according to claim 1, characterized in that: The exhaust passage (210) has at least two bends (213). Among two adjacent bends (213), the second transition passage connected to the bend (213) in front simultaneously constitutes the first transition passage connected to the bend (213) in the rear. The cross-sectional area of ​​the front end of the second transition passage is greater than the cross-sectional area of ​​the rear end of the bend (213) it connects to.

3. The arc-eliminating device according to claim 1, characterized in that: Both the first transition channel and the second transition channel are funnel-shaped channels with a front flow cross-sectional area larger than the rear flow cross-sectional area. The flow cross-sectional area at the rear end of the first transition channel is equal to the flow cross-sectional area at the front end of the bend (213) it connects to. The part where the first transition channel connects to the bend (213) has a smooth inner wall. The front end of the second transition channel forms a widened groove (214) on one or both sides of the end of the bend (213).

4. The arc-eliminating device according to claim 1, characterized in that: The cover (240) is provided with at least one second mounting cavity (241). A channel forming block (220) is fixed in the second mounting cavity (241). A flow channel groove (221) is provided on one or both sides of the channel forming block (220). An exhaust channel (210) is formed by the flow channel groove (221) on the side of the channel forming block (220) cooperating with the inner wall of the second mounting cavity (241) or the inner wall of the second mounting cavity (241) and the inner wall of the circuit breaker housing (110). The cover (240) is provided with a first opening (242) and a second opening (243) respectively corresponding to the air inlet (211) and air outlet (212) of the exhaust channel (210). The arc extinguishing plate (231) is fixed in the flow channel groove (221).

5. The arc-eliminating device according to claim 4, characterized in that: The cover (240) is provided with a second mounting port for inserting the channel forming block (220) into the second mounting cavity (241).

6. A molded case circuit breaker, comprising a circuit breaker body (100), the circuit breaker body (100) including a circuit breaker housing (110) and a contact system (120), an operating mechanism (130), an arc extinguishing system (140), and an overload protection system located within the circuit breaker housing (110), wherein the circuit breaker housing (110) is provided with an arc discharge outlet (115) corresponding to the arc-emitting end of the arc extinguishing system (140), characterized in that: It also includes an arc extinguishing device (200) as described in any one of claims 1-5, wherein the air inlet (211) of the arc extinguishing device (200) is connected to the arc discharge outlet (115) of the circuit breaker housing (110) for collecting the gas discharged from the circuit breaker body (100).

7. The molded case circuit breaker according to claim 6, characterized in that: The circuit breaker housing (110) forms an arc-extinguishing outlet (115) above the arc-extinguishing system (140) and at the tail of the arc-extinguishing system (140). The arc-extinguishing device (200) is connected above the base (111) and to the side of the top cover (112).

Images