Arc extinguish chamber of low-voltage circuit breaker

Abstract

The invention belongs to the technical field of circuit breakers, and relates to an arc extinguishing chamber of a low-voltage circuit breaker, which comprises a shell, an air inlet arranged at the bottom of the shell, an air outlet arranged at the top of the shell, and a plurality of arc extinguishing grid plates arranged between the air inlet and the air outlet in parallel, a first arc isolating cover and a second arc isolating cover are oppositely arranged on the inner walls of the two sides of the air inlet and are provided with inclined side walls from bottom to top and from inside to outside, so that the air inlet forms a Venturi pipeline structure with a wide lower part and a narrow upper part; the Venturi pipeline structure is used as a moving contact opening and closing receding groove. Compared with the prior art, a group of isolation hoods are oppositely arranged at the air inlet of the arc extinguish chamber, and the side walls of the isolation hoods are designed to be the inclined side walls which obliquely extend inwards, so that a Venturi pipeline which is narrow at the upper part and wide at the lower part is formed at the air inlet of the arc extinguish chamber, air flow is enabled to quickly circulate, and electric arcs are driven to quickly enter the arc extinguish chamber.

Description

Technical Field

[0001] This invention belongs to the field of circuit breaker technology and relates to an arc-extinguishing chamber for a low-voltage circuit breaker. Background Technology

[0002] Low-voltage frame circuit breakers are high-capacity low-voltage electrical devices mainly used in industrial power systems to ensure the normal connection and disconnection of circuits, as well as to automatically disconnect circuits under abnormal conditions (such as overload and short circuit).

[0003] like Figure 1 As shown, the arc-extinguishing chamber of the low-voltage circuit breaker adopts an arc-extinguishing grid structure, including a top cover 1, a pair of side plates 2, a bent plate 3 at one end of the pair of side plates, an arc-isolating cover 4 at the bottom of the pair of side plates, and arc-extinguishing plates 5 arrayed between the pair of side plates 2. The arc-extinguishing plates 5 and the bent plate 3 are metal grids, and the side plates 2 are made of insulating material. The arc-extinguishing plates 5 and the bent plate 3 are placed parallel to the side plates 2 perpendicular to them. When the circuit breaker performs opening and closing operations, the contact system generates an electric arc during the operation. Under the magnetic field and "air blowing" effect of the arc-extinguishing chamber, the electric arc enters the arc-extinguishing chamber, where the arc-extinguishing plates 5 divide and cool the arc. With the development of the electricity market, the requirements for the operating voltage of the power system are constantly increasing. The electric arc generated by extremely high voltage can easily damage electrical components.

[0004] The most direct way to dissipate the electric arc in existing arc-extinguishing chambers is to increase the number of arc-extinguishing discs 5. However, this not only occupies a large amount of space, but also cannot guarantee that the electric arc will completely enter the arc-extinguishing chamber, thus reducing the effectiveness of the arc-extinguishing discs 5. The electric arc then causes extensive damage inside the circuit breaker, easily leading to internal welding. At the same time, although a large-scale enclosed structure can reduce arc-spraying to some extent, it does not take into account the fact that the internal pressure of the circuit breaker can damage it. Summary of the Invention

[0005] The purpose of this invention is to provide an arc-extinguishing chamber for a low-voltage circuit breaker, which can quickly extinguish electric arcs and thus reduce the damage of electric arcs to the circuit breaker structure.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] An arc-extinguishing chamber includes a shell, an air inlet at the bottom of the shell, an air outlet at the top of the shell, and a plurality of arc-extinguishing grids arranged in parallel between the air inlet and the air outlet.

[0008] The air inlet is provided with a first arc-blocking cover and a second arc-blocking cover on the inner walls on both sides. The first arc-blocking cover and the second arc-blocking cover have inclined side walls from bottom to top and from inside to outside, so that the air inlet forms a Venturi tube structure that is wider at the bottom and narrower at the top. The Venturi tube effect is to increase the flow rate so that the electric arc can quickly enter the arc-extinguishing chamber and be extinguished.

[0009] The Venturi pipe structure is used as a movable contact opening and closing slot.

[0010] Further, a top cover is further arranged on the air outlet of the top of the shell, and a plurality of air holes are formed in the top cover.

[0011] Further, a plurality of porous isolation sheets are arranged in the top cover.

[0012] Further, the plurality of porous isolation sheets comprise a first porous isolation sheet and a second porous isolation sheet arranged at intervals.

[0013] Further, the shell comprises a set of oppositely arranged side plates and a set of oppositely arranged curved plates and vertical plates.

[0014] The side plates, curved plates and vertical plates form a shell through from top to bottom.

[0015] Further, a gap air hole is formed in the top cover, and a gap is arranged between the outer side of the curved plate and the circuit breaker shell, which is used as an exhaust channel and extends from the gap air hole to the movable contact working space.

[0016] Further, the arc extinguishing grid is perpendicular to the side plate, the curved plate comprises a straight plate segment and a curved plate segment, the straight plate segment is parallel to the arc extinguishing grid together with the vertical plate, and the curved plate segment is bent towards the upper end of the Venturi pipe structure and is arranged at intervals from the movable contact.

[0017] Further, one side of the first arc isolation cover and the second arc isolation cover is provided with a bent opening groove, the curved plate segment of the curved plate is embedded in the bent opening groove, a straight opening groove is formed in the side plate, and the straight plate segment is embedded in the straight opening groove to fix the curved plate between the side plates.

[0018] Further, the arc extinguishing grid comprises a straight plate type arc extinguishing grid group and an inverted U-shaped arc extinguishing grid group, the straight plate type arc extinguishing grid group is distributed on both sides of the inverted U-shaped arc extinguishing grid group, and the two ends of the inverted U-shaped arc extinguishing grid group respectively extend into the first arc isolation cover and the second arc isolation cover. The first arc isolation cover and the second arc isolation cover shield the arc extinguishing grid to maintain pressure.

[0019] Further, the two ends of the inverted U-shaped arc extinguishing grid group are lower than the movable contact. That is, it is ensured that the silver point of the movable contact is always in the first arc isolation cover and the second arc isolation cover during the opening and closing process, and is higher than the lowest point of the arc extinguishing piece 5-2 pin.

[0020] Further, rivet grooves are formed in the first arc isolation cover and the second arc isolation cover, and rivet holes are formed in the side plates, and the first arc isolation cover and the corresponding side plate and the second arc isolation cover and the corresponding side plate are connected through the rivets which are riveted in the rivet grooves through the rivet holes.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] 1) The present application forms a narrow-top wide-bottom Venturi duct at the air inlet of the arc-extinguishing chamber by oppositely arranging a set of isolation covers at the air inlet of the arc-extinguishing chamber and designing the side walls of the isolation covers as inwardly inclined and extended inclined side walls, so that the airflow is rapidly circulated and the arc is rapidly driven into the arc-extinguishing chamber.

[0023] 2) The present application shields the lower end of the arc-extinguishing grid by the isolation cover, and forms a plurality of air holes in communication with the inside of the circuit breaker near the air outlet of the arc-extinguishing chamber, on the top cover and the side plate, so that the rising airflow is not hindered, thereby playing a pressure maintaining role, stabilizing the pressure inside the circuit breaker, reducing the damage to the circuit breaker and prolonging the service life. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a schematic diagram of the inside of the arc-extinguishing chamber of the present application;

[0025] Figure 2 is a partial schematic diagram of the arc-extinguishing chamber of the present application;

[0026] Figure 3 is a schematic diagram of the arc-extinguishing chamber in a low-voltage circuit breaker of the present application;

[0027] Figure 4 is a schematic diagram of the connection of the arc-extinguishing chamber grid of the present application;

[0028] MARK DESCRIPTION IN THE DRAWINGS:

[0029] 1 - top cover, 1-1 - air hole, 1-2 - screw hole, 1-3 - top cover side hole, 1-4 - first porous isolation piece, 1-5 - second porous isolation piece, 2 - side plate, 2-1 - riveting hole, 3 - bent plate, 4 - arc isolation cover, 4-1 - first arc isolation cover, 4-2 - second arc isolation cover, 5 - arc-extinguishing grid, 5-1 - first straight plate type arc-extinguishing grid group, 5-2 - inverted U-shaped arc-extinguishing grid group, 5-3 - second straight plate type arc-extinguishing grid group, 6 - vertical plate. DETAILED DESCRIPTION

[0030] The present application will be described in detail below in conjunction with the drawings and specific embodiments. The following embodiments are implemented on the basis of the above technical solutions of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following embodiments.

[0031] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0032] Some embodiments of the present application will be described in detail with reference to the drawings, which are shown by way of illustration, and without intent to limit the application. The following examples and embodiments can be combined with each other, without conflict.

[0033] Embodiments:

[0034] An arc-extinguishing chamber for quickly extinguishing arc to reduce the damage of arc to the structure of circuit breaker, which comprises a housing, an air inlet arranged at the bottom of the housing, an air outlet arranged at the top of the housing, and a plurality of arc-extinguishing grids 5 arranged in parallel between the air inlet and the air outlet; the inner walls on both sides of the air inlet are oppositely provided with a first arc-shielding cover 4-1 and a second arc-shielding cover 4-2, the first arc-shielding cover 4-1 and the second arc-shielding cover 4-2 have inclined side walls from bottom to top and from inside to outside, so that the air inlet forms a Venturi duct structure with a wide bottom and a narrow top, the Venturi duct structure is used as a moving contact opening slot, and the Venturi effect is formed to increase the flow rate and make the arc quickly enter the arc-extinguishing chamber to be extinguished.

[0035] In some specific embodiments, the housing comprises a set of oppositely arranged side plates 2 and a set of oppositely arranged bent plates 3 and vertical plates 6; the side plates 2, the bent plates 3 and the vertical plates 6 jointly form a housing that is through from top to bottom.

[0036] In some specific embodiments, the arc-extinguishing grids 5 are perpendicular to the side plates 2, the bent plates 3 comprise straight plate segments and bent plate segments, the straight plate segments are parallel to the arc-extinguishing grids 5 together with the vertical plates 6, and the bent plate segments are bent towards the upper end of the Venturi duct structure and are arranged in a spaced manner from the moving contact.

[0037] In some specific embodiments, one side of the first arc-shielding cover 4-1 and the second arc-shielding cover 4-2 is provided with a bent opening groove, the bent plate segments of the bent plates 3 are embedded in the bent opening groove, straight opening grooves are formed on the side plates 2, and the straight plate segments are embedded in the straight opening grooves to fix the bent plates 3 between the side plates 2.

[0038] In some specific embodiments, the arc-extinguishing grids 5 comprise straight plate type arc-extinguishing grid groups and inverted U-shaped arc-extinguishing grid groups 5-2, the straight plate type arc-extinguishing grid groups are distributed on both sides of the inverted U-shaped arc-extinguishing grid groups, comprising a first straight plate type arc-extinguishing grid group 5-1 and a second straight plate type arc-extinguishing grid group 5-3, and the two ends of the inverted U-shaped arc-extinguishing grid group 5-3 respectively extend into the first arc-shielding cover 4-1 and the second arc-shielding cover 4-2. The first arc-shielding cover 4-1 and the second arc-shielding cover 4-2 shield the arc-extinguishing grids 5 to maintain pressure.

[0039] In some specific embodiments, the two ends of the inverted U-shaped arc-extinguishing grid group are lower than the moving contact. That is, it is ensured that the silver points of the moving contact are always in the first arc-shielding cover 4-1 and the second arc-shielding cover 4-2 during the opening and closing process of the moving contact, and are higher than the lowest point of the inverted U-shaped arc-extinguishing grid 5-2.

[0040] In some specific embodiments, a plurality of air holes are formed on the side plates 2, and the air holes are arranged opposite to the intervals of the arc extinguishing fins 5.

[0041] In some specific embodiments, rivet grooves are formed on the first arc separation cover 4-1 and the second arc separation cover 4-2, and a rivet hole 2-1 is formed on the side plate 2. The first arc separation cover 4-1 and the corresponding side plate 2, and the second arc separation cover 4-2 and the corresponding side plate 2 are connected by rivets which are riveted in the rivet grooves through the rivet hole 2-1.

[0042] In some specific embodiments, a top cover 1 is further arranged on the gas outlet of the top of the shell, and a plurality of gap air holes 1-1 are formed on the top cover 1 in addition to the conventional gas outlet holes. A gap is arranged between the outer side of the bending plate 3 of the arc extinguishing chamber and the shell of the circuit breaker, and the gap can be 1-3 mm. The gap serves as an exhaust channel, and extends from the gap air holes 1-1 to the working space of the movable contact. The exhaust channel is used to maintain pressure and guide the movement of the gas.

[0043] In some specific embodiments, a porous isolation sheet is arranged in the top cover 1. Preferably, the porous isolation sheet includes a first porous isolation sheet 1-4 and a second porous isolation sheet 1-5 which are arranged at intervals.

[0044] In some specific embodiments, the top cover 1 and the side plate 2 are connected by screws at the side hole 1-3 of the top cover.

[0045] In some specific embodiments, the arc extinguishing chamber is installed in the circuit breaker by four screws at the screw holes 1-2 of the top cover 1.

[0046] The above description of the embodiments is for the purpose of enabling and using the invention by those of ordinary skill in the art. Those skilled in the art can easily make various modifications to the embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art based on the disclosure of the present application without departing from the scope of the present application should be within the protection scope of the present application.

Claims

1. An arc quenching chamber, characterized in that, The shell, the air inlet arranged at the bottom of the shell, the air outlet arranged at the top of the shell, and a plurality of arc extinguishing fins (5) arranged between the air inlet and the air outlet in parallel; First arc separation cover (4-1) and second arc separation cover (4-2) are arranged on the inner walls on both sides of the air inlet, and the first arc separation cover (4-1) and the second arc separation cover (4-2) have inclined side walls from bottom to top and from inside to outside, so that the air inlet forms a venturi pipeline structure with a wide bottom and a narrow top. The venturi pipeline structure is used as a moving contact opening and closing gap.

2. The arc chute according to claim 1, characterized in that The top cover (1) is arranged on the air outlet at the top of the shell, and a plurality of air holes are formed in the top cover (1).

3. The arc chute of claim 2, wherein, A porous isolation sheet is arranged in the top cover (1).

4. The arc chute of claim 1, wherein, The shell includes a set of oppositely arranged side plates (2) and a set of oppositely arranged bent plates (3) and vertical plates (6). The side plates (2), the bent plates (3) and the vertical plates (6) form a shell that penetrates from top to bottom.

5. The arc chute of claim 4, wherein, Gap air holes (1-1) are formed in the top cover (1), and a gap is arranged between the outer side of the bent plate (3) and the circuit breaker shell, which serves as an exhaust passage extending from the gap air holes (1-1) to the moving contact working space.

6. The arc chute of claim 4, wherein, The arc extinguishing fins (5) are perpendicular to the side plates (2), the bent plate (3) includes a straight plate segment and a bent plate segment, the straight plate segment is parallel to the arc extinguishing fins (5) together with the vertical plate (6), and the bent plate segment is bent towards the upper end of the venturi pipeline structure and is arranged in a spaced manner from the moving contact.

7. The arc chute of claim 6, wherein, One side of the first arc separation cover (4-1) and the second arc separation cover (4-2) is provided with a bent slot, the bent plate segment of the bent plate (3) is embedded in the bent slot, and a straight slot is formed in the side plate (2), and the straight plate segment is embedded in the straight slot to fix the bent plate (3) between the side plates (2).

8. The arc chute of claim 4, wherein, The arc extinguishing fins (5) include a straight plate type arc extinguishing fin group and an inverted U-shaped arc extinguishing fin group, the straight plate type arc extinguishing fin group is distributed on both sides of the inverted U-shaped arc extinguishing fin group, and the two ends of the inverted U-shaped arc extinguishing fin group extend into the first arc separation cover (4-1) and the second arc separation cover (4-2) respectively.

9. The arc chute of claim 8, wherein, The two ends of the inverted U-shaped arc extinguishing fin group are lower than the moving contact.

10. The arc chute of claim 4, wherein, Riveting grooves are formed in the first arc separation cover (4-1) and the second arc separation cover (4-2), riveting holes (2-1) are formed in the side plates (2), and the first arc separation cover (4-1) and the corresponding side plate (2) and the second arc separation cover (4-2) and the corresponding side plate (2) are connected by rivets passing through the riveting holes (2-1) and riveting in the riveting grooves.

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