SWITCHING DEVICE AND ARC EXTINGUISHING CHAMBER THEREOF

Abstract

 A switching device and an arc-extinguishing chamber thereof are provided. The arc-extinguishing chamber includes a first contact, a second contact, arcing rings arranged between the first contact and the second contact and forming an arc gap, and a third contact arranged between the first contact and the second contact and axially moving. The arc-extinguishing chamber further includes a circumferential thermal expansion chamber and an axial thermal expansion chamber. The circumferential thermal expansion chamber is configured to collect circumferential arc energy. The circumferential thermal expansion chamber circumferentially surrounds the arc gap between the arcing rings. The axial thermal expansion chamber is configured to collect axial arc energy. The axial thermal expansion chamber is arranged on a side of the first contact away from the second contact. The axial thermal expansion chamber is in communication with the arc gap. The third contact, in opening movement, moves away from the first contact and towards the second contact. A part of the generated arc energy enters the axial thermal expansion chamber by means of axial air flow, and another part of the arc energy enters the circumferential thermal expansion chamber by means of air convection and radiation through the arc gap, utilizing all the arc energy, avoiding waste, and thereby improving utilization of the arc energy.

Description

[0001] The present application claims priority to Chinese Patent Application No. 202010866044.8, titled "SWITCHING DEVICE AND ARC-EXTINGUISHING CHAMBER THEREOF", filed on August 25, 2020 with the Chinese Patent Office, which is incorporated herein by reference in its entirety.

FIELD

[0002] The present disclosure relates to the technical field of switches, in particular to a switching device, and more particularly to an arc-extinguishing chamber.

BACKGROUND

[0003] When a circuit breaker is opened, an arc is generated between fractures, and the arc has an extremely high temperature. According to an energy formula of W=I2Rt, the arc carries huge energy. According to a designed arc-extinguishing chamber, an air pressure in a thermal expansion chamber is increased by the arc energy, thereby forming a pressure difference between pressure inside the thermal expansion chamber and pressure outside the thermal expansion chamber. Then, when a current crosses zero, molecules in a thermally dissociated state between the fractures are quickly taken away based on the pressure difference, thereby extinguishing the arc. The principle of extinguish an arc based on arc energy is called self-energy arc-extinguishing principle.

[0004] To turn off a SF6 circuit breaker, it is required to achieve a sufficiently high air pressure in the expansion chamber. The air pressure may be generated in various manners, including a mechanical manner and a self-energy manner. In the mechanical manner, an operating mechanism drives a piston in a pressure cylinder to move to forcibly press air into the expansion chamber to increase the pressure. For a circuit breaker, especially a circuit breaker for breaking large currents, the volume of the circuit breaker and the volume of the associated operating mechanisms are to be particularly huge if the air pressure is formed in the mechanical manner, resulting in no economic and performance practicability. Currently, based on the self-energy arc-extinguishing principle, it can greatly reduce the requirement for the mechanism manipulation work to form the air pressure in the expansion chamber.

[0005] When a conventional circuit breaker having a constant contact travel is opened, a moving contact moves along an axis. When the moving contact moves to a side of an arcing pilot ring, arcing occurs permanently between the two arcing pilot rings. The arc generally heats the thermal expansion chamber through a gap (hereinafter referred to as an arc gap) between two arcing pilot rings.

[0006] Macroscopically, an arc is equivalent to a charged conductor and generates a magnetic field. Essentially, an arc is a charged plasma and is affected by a magnetic field. Therefore, an arc tends to shrink under the influence of a magnetic field of the arc itself. A greater breaking current indicates a greater shrinkage pressure. The heating of the thermal expansion chamber by the arc is mainly thermal radiation due to the shrinkage effect of the arc, and the arc gap is not large, resulting in a low efficiency of the arc heating the expansion chamber through the arc gap.

[0007] Therefore, how to provide an arc-extinguishing chamber to improve utilization of arc energy is a problem urgently to be solved by those skilled in the art.

SUMMARY

[0008] In view of this, an arc-extinguishing chamber is provided according to the present disclosure to improve utilization of arc energy. In addition, a switching device with the arc-extinguishing chamber is further provided according to the present disclosure.

[0009] To achieve the above objects, the following technical solutions are provided according to the present disclosure.

[0010] An arc-extinguishing chamber is provided. The arc-extinguishing chamber includes a first contact, a second contact, arcing rings arranged between the first contact and the second contact and forming an arc gap, and a third contact arranged between the first contact and the second contact and axially moving. The arc-extinguishing chamber further includes a circumferential thermal expansion chamber and an axial thermal expansion chamber. The circumferential thermal expansion chamber is configured to collect circumferential arc energy. The circumferential thermal expansion chamber circumferentially surrounds the arc gap between the arcing rings. The axial thermal expansion chamber is configured to collect axial arc energy. The axial thermal expansion chamber is arranged on a side of the first contact away from the second contact. The axial thermal expansion chamber is in communication with the arc gap. The third contact, in opening movement, moves away from the first contact and towards the second contact.

[0011] In an embodiment, the arc-extinguishing chamber further includes a pressure cylinder. The pressure cylinder (6) is configured to supply high-pressure air to the circumferential thermal expansion chamber. The pressure cylinder is in communication with the circumferential thermal expansion chamber.

[0012] In an embodiment, the arcing rings include a first arcing ring close to the first contact and a second arcing ring close to the second contact. The arc gap is formed between the first arcing ring and the second arcing ring. After the third contact moves away from the first contact, the axial thermal expansion chamber is communicated with the arc gap via a space inside the first contact.

[0013] In an embodiment, the axial thermal expansion chamber is symmetrically arranged along a center line of the third contact.

[0014] In an embodiment, the axial thermal expansion chamber is of metal structure, and an inner surface of the axial thermal expansion chamber is covered with a high-temperature resistant material.

[0015] In an embodiment, the axial thermal expansion chamber is arranged with a pressure relief port at an end of the axial thermal expansion chamber away from the first contact. The pressure relief port is arranged with a pressure relief valve for controlling the pressure relief port to be opened or closed. The pressure relief valve is controlled open the pressure relief port in a case that a pressure in the axial thermal expansion chamber reaches a preset value.

[0016] In an embodiment, the axial thermal expansion chamber is arranged with a guiding plate on an end surface of the axial thermal expansion chamber away from the third contact. The guiding plate is gradually expanded from a free end of the guiding plate to an end of the guiding plate connected to the axial thermal expansion chamber. The free end of the guiding plate faces the third contact.

[0017] A switching device is provided. The switching device includes the arc-extinguishing chambers described according to any one of the above embodiments.

[0018] With the arc-extinguishing chamber according to the present disclosure, a part of the generated arc energy enters the axial thermal expansion chamber by means of axial air flow, and another part of the arc energy enters the circumferential thermal expansion chamber by means of air convection and radiation through the arc gap. Based on the above structure, a thermal expansion chamber is arranged in each of possible flow directions of the arc, utilizing all the arc energy, avoiding waste, and thereby improving utilization of the arc energy.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate technical solutions in embodiments of the present disclosure or in the conventional technology, drawings to be used in the description of the embodiments or the conventional technology are briefly described below. Apparently, the drawings in the following description show only some embodiments of the present disclosure, and other drawings may be obtained by those skilled in the art from the drawings without any creative work.

[0020] Figure 1 is a schematic structural diagram of an arc-extinguishing chamber according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0021] An arc-extinguishing chamber is provided according to the present disclosure to improve utilization of arc energy. In addition, a switching device including the arc-extinguishing chamber is further provided according to the present disclosure.

[0022] Hereinafter, technical solutions in the embodiments of the present disclosure are described clearly and completely in conjunction with the drawings in the embodiments of the present disclosure. It is apparent that the described embodiments are only some embodiments of the present disclosure, rather than all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without any creative work fall within the protection scope of the present disclosure.

[0023] As shown in Figure 1, an arc-extinguishing chamber, that is, at least one arcing system, is provided according to the present disclosure. The arcing system includes a first contact 2, a second contact 7, arcing rings, a third contact 8, a circumferential thermal expansion chamber 5, and an axial thermal expansion chamber 3. The arcing rings are arranged between the first contact 2 and the second contact 7, and form an arc gap B. The third contact 8 is arranged between the first contact 2 and the second contact 7, and axially moves. The third contact 8, at a position corresponding to closing, contacts the first contact 2 and the second contact 7, and the third contact 8, at positions corresponding to opening, moves away from the first contact 2 and towards the second contact 7. In this process, after the third contact 8 moves away from the first contact 2, an arc is generated between the third contact 8 and the first contact 2. A part of generated arc energy enters the axial thermal expansion chamber 3 by means of axial air flow, and another part of the arc energy enters the circumferential thermal expansion chamber 5 by means of air convection and radiation through the arc gap B. Based on the above structure, a thermal expansion chamber is arranged in each of possible flow directions of the arc, utilizing all the arc energy, avoiding waste, and thereby improving utilization of the arc energy.

[0024] In an embodiment, the arc-extinguishing chamber further includes a pressure cylinder 6. The pressure cylinder 6 is configured to supply high-pressure air to the circumferential thermal expansion chamber 5. The pressure cylinder 6 is in communication with the circumferential thermal expansion chamber 5. Specifically, the pressure cylinder 6 is in communication with the circumferential thermal expansion chamber 5 via several passages. A piston in the pressure cylinder 6 moves to compress the air in the pressure cylinder 6 to increase the pressure in the pressure cylinder 6, so that high-pressure air is pressed into the circumferential thermal expansion chamber 5 via the passages. The pressure cylinder is configured to perform the following two functions. For a first function, before the third contact 8 moves away from the first contact 2 (that is, before generating an arc), the air in the pressure cylinder 6 is pressed into the circumferential thermal expansion chamber 5 to increase a base air pressure in the circumferential thermal expansion chamber 55, so that the air is heated and boosted from a high pressure. For a second function, in a case of breaking a small current, the arc energy is not enough to establish sufficient pressure in the circumferential thermal expansion chamber 5, thus it is required to establish a pressure by using the pressure cylinder 6. The pressure cylinder 6 according to the present disclosure includes two bottom surfaces 10 and an annular insulating cylinder arranged between the two bottom surfaces.

[0025] In a case of breaking a large current, an axial air flow of the arc enters the axial thermal expansion chamber 3 to heat the air to boost the pressure of the air, and molecules in a thermally dissociated state between the fractures are taken away by the air in the axial thermal expansion chamber 3 when the current crosses zero. In a case of breaking a small current, air is injected into the circumferential thermal expansion chamber 5 by using the pressure cylinder 6 to increase the pressure in the circumferential thermal expansion chamber 5 due to unobvious heating effect of the arc, and molecules in a thermally dissociated state between the fractures are taken away by the air in the circumferential thermal expansion chamber 5 when the current crosses zero. In summary, the two thermal expansion chambers perform functions respectively, thereby breaking various currents with the arc-extinguishing chamber.

[0026] In an embodiment, the arcing rings includes a first arcing ring 1 close to the first contact 2 and a second arcing ring 9 close to the second contact 7. The arc gap B is formed between the first arcing ring 1 and the second arcing ring 9. The axial thermal expansion chamber 3 is communicated with the arc gap B via a moving space of the third contact 8. Specifically, each of the first contact 2, the second contact 7 and the arcing rings has an annular structure. The third contact 8 axially moves along an inner ring of the annular structure. When the third contact 8 moves to a position between the first arcing ring 1 and the second arcing ring 9, the generated air with arc energy enters the axial thermal expansion chamber 3 through the arc gap B and a space left by the third contact 8. A communication manner in which the axial thermal expansion chamber 3 is communicated with the arc gap B is disclosed herein. In practice, the communication manner may be configured according to actual requirements. Alternatively, the axial thermal expansion chamber 3 may be in communication with the arc gap B through a pipeline.

[0027] The axial thermal expansion chamber 3 is symmetrically arranged along a center line of the third contact 8, facilitating processing, installation, and collection of the axial arc energy. In practice, different arrangements may be performed according to different requirements.

[0028] The axial thermal expansion chamber 3 may be made of metal material or high-strength insulating material. Due to the high temperature of the airflow entering the axial thermal expansion chamber 3, a first inner wall 3a, a second inner wall 3b and a third inner wall 3c of the axial thermal expansion chamber 3 are preferably covered with an ablation resistant insulating material. The covering may be performed in a coating manner to reduce thermal damage to the material. The insulating material may be polytetrafluoroethylene.

[0029] In an embodiment, the axial thermal expansion chamber 3 according to the present disclosure is arranged with a pressure relief port at an end of the axial thermal expansion chamber 3 away from the first contact 2. The pressure relief port is arranged with a pressure relief valve 4 for controlling the pressure relief port to be opened or closed. In a case that a pressure in the axial thermal expansion chamber 3 reaches a preset value, the pressure relief valve 4 is controlled to open the pressure relief port. Specifically, the pressure relief valve 4 does not act in a case that the arc-extinguishing chamber is in normal operation. In a case that the arc-extinguishing chamber fails to extinguish the arc due to failure of a component of the arc-extinguishing chamber, an axial air flow generated by the arc energy continuously enters the axial thermal expansion chamber 3, thus the air pressure in the axial thermal expansion chamber 3 is increased, resulting in an risk of permanent mechanical damage to the arc-extinguishing chamber. When the air pressure in the axial thermal expansion chamber 3 reaches a preset value, the pressure relief valve 4 acts to release the air pressure in the axial thermal expansion chamber 3, thereby avoiding mechanical damage to the arc-extinguishing chamber.

[0030] The axial thermal expansion chamber 3 according to the present disclosure is arranged with a guiding plate on an end surface of the axial thermal expansion chamber 3 away from the third contact 8, so that the axial air flow into the axial thermal expansion chamber 3 quickly diffuses to an edge of the axial thermal expansion chamber 3. The guiding plate is gradually expanded from a free end of the guiding plate to an end of the guiding plate connected to the axial thermal expansion chamber 3, and the free end of the guiding plate faces the third contact 8. That is, a conical protrusion is arranged in a center of an end of the axial thermal expansion chamber 3. In practice, the conical protrusion may be integrated with the pressure relief valve 4, that is, the conical protrusion is a part of the pressure relief valve 4, realizing quick installation and thereby improving assembly efficiency.

[0031] A sum of volumes of the circumferential thermal expansion chamber 5 and the axial thermal expansion chamber 3 in the present disclosure is equivalent to a volume of a single thermal expansion chamber of an arc-extinguishing chamber interrupting a same current as a current of the circumferential thermal expansion chamber 5 and the axial thermal expansion chamber 3, so as to collect more arc energy with the same volume of the thermal expansion chamber. The dimensions of the circumferential thermal expansion chamber 5 and axial thermal expansion chamber 3 may be determined according to the actual requirements, which fall within the protection scope of the present disclosure.

[0032] In addition, a switching device, including the arc-extinguishing chamber according to the above embodiments, is further provided according to the present disclosure. Therefore, the above technical effects can be achieved with the switching device including the arc-extinguishing chamber, which are not repeated herein.

[0033] The embodiments in this specification are described in a progressive way. Each of the embodiments emphasizes the differences from others, and the same or similar parts of the embodiments can be referred to each other.

[0034] Based on the above description of the disclosed embodiments, those skilled in the art can implement or carry out the present disclosure. It is apparent for those skilled in the art to make various modifications to these embodiments. The general principle defined herein may be applied to other embodiments without departing from the content or scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the embodiments illustrated herein, but should be defined by the widest scope consistent with the principle and novel features disclosed herein.

Claims

1. An arc-extinguishing chamber, comprising a first contact (2), a second contact (7), arcing rings arranged between the first contact (2) and the second contact (7) and forming an arc gap, and a third contact (8) arranged between the first contact (2) and the second contact (7) and axially moving, wherein the arc-extinguishing chamber further comprises:

a circumferential thermal expansion chamber (5), configured to collect circumferential arc energy, wherein the circumferential thermal expansion chamber (5) circumferentially surrounds the arc gap between the arcing rings; and

an axial thermal expansion chamber (3), configured to collect axial arc energy, wherein the axial thermal expansion chamber (3) is arranged on a side of the first contact (2) away from the second contact (7), the axial thermal expansion chamber (3) is in communication with the arc gap, and the third contact (8), in opening movement, moves away from the first contact (2) and towards the second contact (7).

2. The arc-extinguishing chamber according to claim 1, further comprising:
a pressure cylinder (6), configured to supply high-pressure air to the circumferential thermal expansion chamber (5), wherein the pressure cylinder (6) is in communication with the circumferential thermal expansion chamber (5).

3. The arc-extinguishing chamber according to claim 1, wherein
the arcing rings comprise a first arcing ring (1) close to the first contact (2) and a second arcing ring (9) close to the second contact (7), the arc gap is formed between the first arcing ring (1) and the second arcing ring (9), and after the third contact (8) moves away from the first contact (2), the axial thermal expansion chamber (3) is communicated with the arc gap via a space inside the first contact (2).

4. The arc-extinguishing chamber according to claim 1, wherein
the axial thermal expansion chamber (3) is symmetrically arranged along a center line of the third contact (8).

5. The arc-extinguishing chamber according to claim 1, wherein
the axial thermal expansion chamber (3) is of metal structure, and an inner surface of the axial thermal expansion chamber (3) is covered with a high-temperature resistant material.

6. The arc-extinguishing chamber according to claim 1, wherein
the axial thermal expansion chamber (3) is arranged with a pressure relief port at an end of the axial thermal expansion chamber (3) away from the first contact (2), the pressure relief port is arranged with a pressure relief valve (4) for controlling the pressure relief port to be opened or closed, and the pressure relief valve (4) is controlled to open the pressure relief port in a case that a pressure in the axial thermal expansion chamber (3) reaches a preset value.

7. The arc-extinguishing chamber according to any one of claims 1 to 6, wherein
the axial thermal expansion chamber (3) is arranged with a guiding plate on an end surface of the axial thermal expansion chamber (3) away from the third contact (8), the guiding plate is gradually expanded from a free end of the guiding plate to an end of the guiding plate connected to the axial thermal expansion chamber, and the free end of the guiding plate faces the third contact (8).

8. A switching device, comprising the arc-extinguishing chamber according to any one of claims 1 to 7.

Drawing