Direct-current change-over switch on-off device

Abstract

The utility model relates to the technical field of high-voltage or large-current switches with arc extinguishing or anti-arc devices, in particular to an on-off device of a direct-current change-over switch. The direct-current change-over switch on-off device comprises a sealing device, the sealing device comprises a cylindrical shell used for being installed on the end face of the end, away from an arc extinguish chamber, of a supporting column, the shell is provided with a sealing matching structure used for being matched with the supporting column in a sealing mode, and an annular permanent magnet is arranged in the shell. Pole shoe rings are arranged on the two sides of the permanent magnet, magnetic liquid is arranged on the inner walls of the pole shoe rings, the inner diameter of the permanent magnet is larger than that of the pole shoe rings, a limiting part with a center hole is arranged at one end of the shell, an end cover with a center hole is arranged at the other end of the shell, and the annular magnet and the pole shoe rings in the shell are clamped and fixed through the end cover and the limiting part. The sealing performance, especially the dynamic sealing performance, of the insulating pull rod of the device is good, and the air leakage phenomenon can be effectively prevented.

Description

TECHNICAL FIELD

[0001] The utility model relates to high pressure or large current switch technical field with arc extinguishing or arc reversal device, especially a kind of DC transfer switch breaking device. BACKGROUND

[0002] High voltage circuit breaker mainly plays control and protection in electrical system, and sulfur hexafluoride circuit breaker has excellent insulation performance and arc extinguishing performance due to the electronegativity of its insulating medium, and plays an important role in power system. The DC transfer switch breaking device includes a support, an insulating pull rod coaxially arranged inside the support, one end of the insulating pull rod extending out of the support, the insulating pull rod and the support being slidably connected through a sealing structure, the end of the insulating pull rod extending out of the support being connected to an operating mechanism, and a three-way box being connected to the end of the support away from the operating mechanism and connected to an arc extinguishing chamber through the three-way box.

[0003] Since the sulfur hexafluoride circuit breaker is filled with sulfur hexafluoride gas inside to achieve insulation and arc extinguishing, the circuit breaker has high air tightness requirements. The insulation performance of sulfur hexafluoride gas mainly depends on its density, and a decrease in density will lead to a decrease in insulation performance and arc extinguishing ability. In addition, the decrease in density is mainly caused by gas leakage, and the leakage of gas is often accompanied by the penetration of external moisture, which will increase the water content of sulfur hexafluoride gas and cause the problem of micro-water exceeding the standard, seriously affecting the insulation and arc extinguishing function of the circuit breaker and unable to ensure safe and stable operation.

[0004] At present, the main sealing measure is to use a sealing ring to achieve sealing at the connection, but under the condition of excessive stress, the sealing ring is prone to aging, damage and deformation, resulting in a decrease in air tightness and easy gas leakage. When the circuit breaker is working, the insulating pull rod reciprocates, and due to the poor dynamic sealing effect of the mechanical seal of the sealing ring, gas leakage is prone to occur, thereby causing a fault of the high voltage circuit breaker. UTILITY MODEL CONTENTS

[0005] The utility model aims to provide a DC transfer switch breaking device to solve the problem of poor dynamic sealing performance and serious gas leakage of the current sulfur hexafluoride circuit breaker.

[0006] The utility model adopts the following technical solutions:

[0007] The application discloses a DC transfer switch breaking device, which comprises a sealing device, the sealing device comprises a cylindrical shell used for being mounted on an end face of a support far away from an arc-extinguishing chamber, a sealing cooperation structure used for sealing cooperation with the support is arranged on the shell, an annular permanent magnet is arranged in the shell, pole shoe rings are arranged on both sides of the permanent magnet, a magnetic liquid is arranged on inner walls of the pole shoe rings, an inner diameter of the permanent magnet is larger than an inner diameter of the pole shoe rings, a limiting part with a central opening is arranged on one end of the shell, an end cover with a central opening is arranged on the other end of the shell, and the end cover and the limiting part clamp and fix the annular magnet and the pole shoe rings in the shell.

[0008] Further, a ring-shaped groove is formed in the inner wall of the pole shoe ring.

[0009] Further, a sealing ring is arranged on the outer wall of the shell, and the sealing cooperation structure is formed by the sealing ring on the outer wall of the shell.

[0010] Further, a sealing ring is arranged between the pole shoe ring and the shell.

[0011] Further, a flange plate used for connecting the support is arranged on the end of the shell far away from the end cover, and bolt holes corresponding to the support are formed in the flange plate.

[0012] Further, a sleeve is arranged on the side of the pole shoe ring far away from the permanent magnet.

[0013] Further, a partition plate is arranged between the sleeve and the pole shoe ring.

[0014] Beneficial effects: The DC transfer switch breaking device is an improved invention. The DC transfer switch breaking device comprises a sealing device, the sealing device comprises a cylindrical shell used for being mounted on an end face of a support far away from an arc-extinguishing chamber, a sealing cooperation structure used for sealing cooperation with the support is arranged on the shell, a limiting sealing part is arranged, an annular permanent magnet is arranged in the shell, pole shoe rings are arranged on both sides of the permanent magnet, a magnetic liquid is arranged on inner walls of the pole shoe rings, an inner diameter of the permanent magnet is larger than an inner diameter of the pole shoe rings, when in operation, the permanent magnet, the pole shoe rings and an insulating pull rod form an annular magnetic field loop, the magnetic liquid is fixed on the inner side of the pole shoe rings under the action of the magnetic field, and the sealing effect is achieved, a limiting part with a central opening is arranged on one end of the shell, an end cover with a central opening is arranged on the other end of the shell, the end cover and the limiting part clamp and fix the annular magnet and the pole shoe rings in the shell, the device is convenient to adjust and disassemble, the sealing performance, especially the dynamic sealing performance, of the insulating pull rod of the device is good, and the device can effectively prevent the occurrence of air leakage. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a structural schematic view of an embodiment of the DC transfer switch breaking device of the application.

[0016] Figure 2 It is a structural schematic view of an embodiment of the DC transfer switch breaking device of the application. Figure 1Partial enlarged view of the sealing device;

[0017] Figure 3 For Figure 1 Schematic view of the installation of the sealing part.

[0018] In the figure: 1, permanent magnet; 2, shell; 3, insulated pull rod; 4, sleeve; 5, pole shoe ring; 6, spacer; 7, magnetic liquid; 8, arc extinguishing chamber; 9, three-way box; 10, support; 11, sealing device; 12, sealing ring; 13, end cover. DETAILED DESCRIPTION

[0019] The features and performance of the utility model are further described in detail below in combination with examples.

[0020] The air tightness of the DC transfer switch breaking device determines the reliability of the DC transfer switch. The utility model discloses the concept of using a magnetic liquid sealing device to replace the sealing ring to ensure the good dynamic sealing performance.

[0021] Based on the above inventive concept, as Figure 1 , 2, 3, in a basic embodiment, the DC transfer switch breaking device of the utility model comprises a sealing device 11, the sealing device 11 comprises a cylindrical shell 2 for being installed at the end face of the support 10 away from the arc extinguishing chamber 8, a sealing cooperation structure for sealing cooperation with the support 10 is arranged on the shell, a limiting sealing part is installed, an annular permanent magnet 1 is arranged in the shell 2, pole shoe rings 5 are arranged on the two sides of the permanent magnet 1, magnetic liquid 7 is arranged on the inner wall of the pole shoe ring 5, the inner diameter of the permanent magnet 1 is greater than the inner diameter of the pole shoe ring 5, when operating, the permanent magnet 1, the pole shoe ring 5 and the insulated pull rod 3 form an annular magnetic field loop, the magnetic liquid 7 is firmly fixed between the pole shoe ring 5 and the insulated pull rod 3 under the action of the magnetic field, plays a sealing role, one end of the shell 2 is provided with a limiting part with a central opening, the other end of the shell 2 is provided with an end cover 13 with a central opening, the end cover 13 and the limiting part clamp and fix the annular magnet and the pole shoe ring 5 in the shell 2, which is convenient for adjusting and dismounting, the sealing performance of the device, especially the dynamic sealing performance of the insulated pull rod 3, is good, which can effectively prevent the occurrence of air leakage and ensure the sealing performance of the arc extinguishing chamber 8 and the three-way box 9. Whether the insulated pull rod reciprocates when the DC transfer switch operates or the DC transfer switch does not operate, the magnetic liquid sealing device 11 can realize its good sealing performance. Compared with the traditional sealing method, the magnetic liquid sealing has the advantages of zero leakage, simple structure, high reliability, long service life, no pollution, convenient use, anti-eccentric vibration, mechanism self-adaptation and the like.

[0022] In the test of the magnetic liquid dynamic and static sealing, the gas tightness is evaluated by a helium mass spectrometer leak detector. Under normal conditions, the leakage of the gas is less than 10-11 (Pa*m3 ) can be identified as zero leakage, while the magnetic liquid 7 is located between the pole shoe ring 5 and the insulating pull rod 3, the viscosity coefficient of the magnetic liquid 7 is small, the viscous friction during reciprocating motion is small, and the magnetic liquid 7 can stably operate.

[0023] The magnetic liquid 7 has multiple names, such as magnetic fluid, magnetic liquid, ferromagnetic fluid, and ferromagnetic liquid. The magnetic liquid 7 is composed of a base solution, a surface-coated active agent, and ferromagnetic particles. The magnetic liquid 7 is a colloidal solution formed by dispersing a large number of ferromagnetic or ferrimagnetic substances in a base liquid, thereby forming a highly stable colloidal solution. The size of the magnetic particles is mostly around 10 nm, and the main component is Fe3O4 particles. The attractive force between the particles is relatively small, but the van der Waals force between them is relatively large, which requires surface-coated active agents to prevent particle aggregation and deposition. The surface active agent is crucial to the stability of the magnetic liquid, and it can affect the success of the preparation of the magnetic liquid 7. The surface active agent is adsorbed on the surface of the magnetic particles, like a spring, maintaining a certain distance between adjacent magnetic particles, thereby avoiding the growth of magnetic particles and the formation of flocculation and deposition, and facilitating the obtaining of small and uniform magnetic particles. The selection of the base liquid should meet the conditions of low evaporation rate, low viscosity, and high chemical stability. Common base liquids include organic oil-based, water-based, ester-based, fluorine ether oil-based, and silicone oil-based.

[0024] The magnetic liquid seal utilizes the characteristics of the magnetic liquid 7 responding to the magnetic field. The magnetic liquid 7 is input into the gap of the magnetic circuit formed by the permanent magnet 1, the pole shoe ring 5 with good magnetic conductivity, and the insulating pull rod 3, forming an "o" type ring. When there is a pressure difference between the inner and outer cavities, the magnetic liquid 7 will resist the pressure difference under the action of the magnetic force, thereby re-establishing the balance.

[0025] In a preferred embodiment, a ring-shaped groove is opened on the inner wall of the pole shoe ring 5. In the rotating magnetic field circuit formed by the permanent magnet 1, the pole shoe ring 5, and the insulating pull rod 3, the magnetic field distribution is more dispersed at the gap between the pole shoe ring 5 and the insulating pull rod 3, and the magnetic force acting on the magnetic liquid 7 is smaller, so the magnetic liquid 7 is more dispersed and not conducive to sealing. After the ring-shaped groove is opened, the rotating magnetic field circuit concentrates the magnetic field along the pole shoe ring 5 at the tip of the ring-shaped groove, ensuring the stability of the seal.

[0026] In another embodiment, the inner wall of the pole shoe ring 5 is not provided with a ring-shaped groove. By enhancing the magnetic force of the permanent magnet 1, a stable and sufficient annular magnetic field is formed by the permanent magnet 1 and the pole shoe ring 5, firmly fixing the magnetic liquid 7 on the inner wall of the pole shoe ring 5, isolating the exchange of gas between the inside and outside, and achieving good sealing performance. Although the distribution of the magnetic liquid 7 is dispersed or concentrated at both ends of the inner wall of the pole shoe ring 5, the sealing function can still be achieved and the device can operate normally.

[0027] In a preferred embodiment, the outer wall of the housing 2 is provided with a sealing ring 12, and the sealing fitting structure is formed by the sealing ring 12 on the outer wall of the housing 2, which can prevent the insulation gas inside the support column 10 from leaking out through the gap between the support column 10 and the housing 2, thereby enhancing the air tightness of the DC switching switch breaking device, ensuring the insulation gas density of the arc extinguishing chamber 8, ensuring good arc extinguishing effect, ensuring the safe operation of the DC switching switch, and enhancing the static sealing performance of the DC switching switch breaking device.

[0028] In other embodiments, the outer wall of the housing 2 is not provided with a sealing ring 12, and by improving the machining precision of the housing 2 and the support column 10, the gap between the housing 2 and the support column 10 is reduced, thereby ensuring good static sealing performance, although the production and processing cost is increased, but the sealing performance can be guaranteed, and normal work can be ensured.

[0029] In a preferred embodiment, a sealing ring 12 is arranged between the pole shoe ring 5 and the housing 2, and a groove for installing the sealing ring 12 is formed on the outer wall of the pole shoe ring 5. By installing the sealing ring, the static sealing performance of the magnetic liquid sealing device 11 is enhanced, and the internal insulation gas is prevented from leaking out through the gap between the pole shoe ring 5 and the housing 2.

[0030] In other embodiments, the pole shoe ring 5 and the housing 2 can also not be provided with a sealing ring, and by improving the machining precision of the pole shoe ring 5 and the housing 2, the gas leakage can be reduced, thereby ensuring good static sealing performance, although the production and processing cost is increased, but the sealing performance can be guaranteed, and normal work can be ensured.

[0031] In a preferred embodiment, the housing 2 is provided with a flange plate at the end away from the end cover 13 for connecting the support column, and the flange plate is provided with bolt holes corresponding to the support column 10. The sealing device 11 is fixed on the support column 10 by bolts, which is simple and fast to assemble, convenient to maintain and replace, and has low difficulty. In other embodiments, welding fixation can also be used, and the sealing device 11 is fixedly connected to the end away from the end cover 13, which can also achieve similar effects and ensure normal work.

[0032] In a preferred embodiment, the pole shoe ring 5 is provided with a sleeve 4 away from the permanent magnet 1, and the sleeve 4 is used to limit the insulation pull rod 3, thereby preventing the insulation pull rod 3 from jumping radially during reciprocating motion and affecting the insulation effect. At the same time, arranging the magnetic liquid sealing device in the axial direction of the insulation pull rod 3 needs to consider the problem of sealing failure. According to relevant documents, the main factors affecting the linear straight sealing of the magnetic liquid 7 are: during the reciprocating motion of the shaft, the loss of the magnetic liquid 7 increases due to the continuous escape of the magnetic liquid 7, and when the sealing ring is disconnected, the sealing leakage occurs, which leads to sealing failure.

[0033] In other embodiments, the sleeve 4 is not provided, although it will result in an increase in the loss of reciprocating motion, reduced service life, and increased maintenance frequency of the magnetic liquid sealing device, but does not affect the core components of the magnetic liquid seal, and the magnetic liquid sealing device 11 can normally realize the sealing function and can normally work.

[0034] In a preferred embodiment, a spacer 6 is provided between the sleeve 4 and the pole shoe ring 5. By providing the spacer 6, the magnetic liquid 7 can be prevented from adhering to the sleeve 4 and penetrating into the gap of the sleeve 4 due to the action of the tension force, resulting in a loss of the magnetic liquid 7, thereby reducing the maintenance frequency of the magnetic liquid sealing device 11. At the same time, the spacer 6 provides a certain cavity for the pole shoe ring 5 and the sleeve 4, allowing more magnetic liquid 7 to be injected, thereby reducing the maintenance frequency of the sealing device 11.

[0035] In other embodiments, the spacer 6 is not provided, and the sleeve 4 is directly installed on the side of the pole shoe ring 5. Although part of the magnetic liquid 7 can penetrate into the inside of the sleeve 4, a sleeve made of a magnetic material can be used to form another annular magnetic field loop, which can enhance the fixation of the magnetic liquid 7 and reduce the loss of the magnetic liquid 7, thereby achieving normal sealing performance.

[0036] When the DC transfer switch opening device is not in action, the insulating pull rod 3 passes through the sealing device 11, and the gap between the insulating pull rod 3 and the sealing device 11 is filled with the magnetic liquid 7. Through the annular magnetic field, the magnetic liquid 7 can withstand the pressure from the sulfur hexafluoride gas inside the support 10, so that the sulfur hexafluoride gas cannot penetrate outward. There is no wear between the sealing device 11 and the insulating pull rod 3, so that the sealing life of the sealing device 11 is much longer than that of ordinary sealing structures, and the reliability is higher.

[0037] When the DC transfer switch opening device is in action, the insulating pull rod 3 starts to reciprocate, the magnetic liquid 7 is firmly adsorbed at the tip of the pole shoe ring 5, forms a stable "O" ring current, and completely seals the gap between the pole shoe ring 5 and the insulating pull rod 3, so that the internal and external gases are isolated, ensuring the density of the internal insulating gas, so that it can be stably and safely operated.

[0038] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. The patent protection scope of the present application is subject to the claims, and any equivalent structural changes made by referring to the content of the specification and drawings should also be included in the protection scope of the present application.

Claims

1. A DC transfer switch opening device comprising a sealing device, characterized in that The sealing device comprises a cylindrical shell for mounting on the end face of the post away from the arc-extinguishing chamber, a sealing structure is arranged on the shell for sealing cooperation with the post, an annular permanent magnet is arranged inside the shell, pole shoe rings are arranged on both sides of the permanent magnet, a magnetic liquid is arranged on the inner wall of the pole shoe rings, the inner diameter of the permanent magnet is larger than the inner diameter of the pole shoe rings, a limiting part with a central opening is arranged on one end of the shell, an end cover with a central opening is arranged on the other end of the shell, and the end cover and the limiting part clamp and fix the annular magnet and the pole shoe rings in the shell.

2. The DC transfer switch disconnect device of claim 1, wherein, An annular groove is arranged on the inner wall of the pole shoe ring.

3. A DC transfer switch disconnect device according to claim 1 or 2, characterized in that A sealing ring is arranged on the outer wall of the shell, and the sealing structure is composed of the sealing ring on the outer wall of the shell.

4. A DC transfer switch disconnect device according to claim 1 or 2, characterized in that A sealing ring is arranged between the pole shoe ring and the shell.

5. A DC transfer switch disconnect device according to claim 1 or 2, characterized in that, A flange plate for connecting the post is arranged on the end of the shell away from the end cover, and bolt holes corresponding to the post are arranged on the flange plate.

6. The DC transfer switch disconnect device of claim 1 or 2, wherein, A sleeve is arranged on the side of the pole shoe ring away from the permanent magnet.

7. The DC transfer switch disconnect device of claim 6, wherein, A partition is arranged between the sleeve and the pole shoe ring.

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