JP2008123761A - Gas-blast circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas-blast circuit breaker excellent in compactification and reliability, capable of, even if a gas pressure in a puffer cylinder is raised by incorporating thermal energy of an arc, surely preventing a gas leak except from a nozzle hole, to thereby realize the further miniaturization and exhibit the excellent breaking performance. <P>SOLUTION: An outer surface of a nozzle 6 and an inner surface of a movable side main contact 4 have a construction to fit to each other. The inner surface of the movable side main contact 4 has a groove 13 formed along a circumferential direction of the nozzle 6 at a fitting surface 12 included in the fitting construction. The groove 13 is fitted with an O-ring 14. A width of the groove 13 is adjusted to compress the O-ring 14 between about 60 to 90% in volume. The O-ring 14 is resilient, thereby providing the gas-tight with the O-ring 14 fitted into the groove 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas circuit breaker having a nozzle for blowing a gas in a puffer cylinder to an arc contact, and in particular, a gas barrier with an improved nozzle mounting structure to prevent gas leakage from other than the nozzle hole. It is about a vessel.

  In recent years, gas-insulated switchgear using SF6 gas as arc-extinguishing gas has become the mainstream in the field of electric power switches that energize a large current. Among them, the puffer type gas circuit breaker is most often used because the gas circuit breaker is required to cut off a large current such as a short circuit current of the system. Here, the basic structure of the puffer-type gas circuit breaker will be specifically described with reference to FIG. FIG. 10 shows a typical configuration of the arc extinguishing chamber of the puffer type gas circuit breaker.

  The arc extinguishing chamber of the puffer-type gas circuit breaker includes a fixed side contact 31 and a movable side contact 32. These contact points 31 and 32 are opposed to each other in a container (not shown) in which SF6 gas is sealed through an insulating cylinder 9 so as to be able to contact and separate. Among these, the fixed contact 31 includes the fixed arc contact 7 and the fixed main contact 8, and the movable contact 32 includes the movable arc contact 5 and the movable main contact 4.

  An operation rod 33 is attached to the movable contact 32. In addition to the movable side arc contact 5 and the movable side main contact 4, the puffer cylinder 2 and the nozzle 6 are fixed to the operation rod 33 to form a movable part. The movable portion is integrally driven by an opening / closing operation mechanism portion (not shown). The movable side main contact 4, the movable side arc contact 5 and the nozzle 6 are coaxially connected to the tip of the puffer cylinder 2 from the inside in the order of the movable side main contact 4, the nozzle 6 and the movable side arc contact 5. It is attached to the shape. Further, the puffer piston 1 is provided at the movable contact 32. The puffer piston 1 is slidably inserted into the puffer cylinder 2, and a puffer chamber 3 is formed by these members.

  In the puffer type gas circuit breaker having the above configuration, the arc contacts 5 and 7 and the main contacts 4 and 8 are in contact with each other in a closed state. During the opening operation, the arc extinguishing chamber movable side is driven by an operating device (not shown) in the opening operation direction indicated by the arrow in FIG. At the beginning of the opening operation, first, the main contacts 4 and 8 are separated from each other, and all currents are transferred to the arc contacts 5 and 7 side. Thereafter, when the arc contacts 5 and 7 are opened, an arc 10 is generated here. At this time, SF6 gas in the puffer chamber 3 is compressed by the puffer piston 1, and the nozzle 6 guides it and blows it to the arc 10, thereby extinguishing the arc 10 and interrupting the current.

  By the way, when interrupting a large current with the above-described puffer type gas circuit breaker, it is necessary to open the arc contacts 5 and 7 at high speed while blowing SF6 gas of high pressure. Therefore, a large output opening / closing operation mechanism is indispensable. Further, in order to spray a large amount of SF6 gas onto the arc 10, the puffer cylinder 2 needs to have a large cross-sectional area. As a result, the size of the arc extinguishing chamber and the entire circuit breaker must be increased. The large output opening / closing mechanism and the breaker having a large size are costly, resulting in an economical disadvantage.

  An attempt to solve these problems is a gas circuit breaker using arc energy generated between the arc contacts 5 and 7. This is because the thermal energy of the arc 10 passes through the movable arc contact 5 and the communication hole 34 and is taken into the puffer chamber 3 again, and the SF6 gas in the puffer chamber 3 is heated using this thermal energy. The gas pressure is increased and SF6 gas is strongly blown to the arc 10 through the nozzle 6 so that a large current is surely interrupted (the arrow A in FIG. 11 indicates the arc 10 from the puffer chamber 3 to the arc 10). It shows a gas flow sprayed with SF6 gas).

  In the gas circuit breaker adopting this method, the amount of gas to be heated is small, that is, the one with a small capacity of the puffer cylinder 2 can raise the gas pressure more effectively. This is also advantageous in reducing the size of the device. Further, since the area of the puffer cylinder 2 is small, there is an advantage that the reaction force generated during the opening operation can be suppressed to a low level and the output of the opening / closing operation mechanism unit can be reduced.

As described above, the gas circuit breaker using the thermal energy of the arc 10 for increasing the gas pressure in the puffer chamber 3 is excellent in miniaturization and has been rapidly spread in recent years. Therefore, the improvement of the gas circuit breaker of this system, such as a nozzle manufacturing process, has been actively performed (for example, Patent Documents 1 and 2).
JP-A-9-223441 JP 2003-297198 A

  However, the following problems have been pointed out in the above prior art. That is, in the gas circuit breaker of the type in which the thermal energy of the arc 10 is taken into the puffer chamber 3, the pressure in the puffer chamber 3 increases as the size of the gas circuit breaker is further reduced. Will go. As a result, SF6 gas may leak from the portion of the nozzle 6 other than the gas spray hole.

  FIG. 11 shows the gas leakage path in this case. As shown in FIG. 11, the fitting surface 12 between the nozzle 6 and the movable main contact 4 is a portion where the gas pressure is highest, and gas may leak from here (illustrated by an arrow B in FIG. 11). . When such a gas leak occurs, the pressure loss increases, and a desired pressure cannot be obtained, which is a problem.

  Further, the gas leaking from the fitting surface 12 suddenly goes out from the narrow space in the puffer chamber 3 to the wide space, so that it is transmitted to drift on the outer surface of the nozzle 6 and reaches the fixed contact 31. At this time, the leaked gas is heated in the puffer chamber 3 by the arc 10, so that it has a high temperature of several hundred degrees or more, and its dielectric strength is lower than that of the normal temperature gas. Therefore, the recovery voltage after the current interruption cannot be withstood, and there is a possibility that the dielectric breakdown between the electrodes may occur through the creeping surface of the nozzle 6. As a result, there was an insulation breakdown between the main contacts 4 and 8, which could lead to a major accident, and improvement was urgently required.

  The present invention has been proposed in order to solve the above problems, and its purpose is to prevent gas leakage from other than the nozzle hole even if the gas pressure in the puffer cylinder is increased by taking in the thermal energy of the arc. An object of the present invention is to provide a gas circuit breaker excellent in compactness and reliability that can cope with further miniaturization and exhibit excellent shut-off performance by reliably preventing it.

  To achieve the above object, the present invention provides a fixed side contact comprising a fixed side arc contact and a fixed side main contact, a movable side arc contact and a movable side main contact in a container sealed with an arc extinguishing gas. The movable side contact is arranged so as to be in contact with and away from the movable side contact, and a puffer chamber comprising a puffer cylinder and a puffer piston slidable in the puffer cylinder is formed on the movable side contact, and the puffer cylinder is formed. A cylindrical nozzle is attached to the tip and outside the movable main contact, and the arc extinguishing gas in the puffer cylinder is compressed by the puffer piston during the opening operation, and the nozzle fixes the arc extinguishing gas to the fixed side. And a gas circuit breaker configured to spray an arc generated between the arc contacts on the movable side and a fitting structure in which the outer surface of the nozzle and the inner surface of the movable side main contact are fitted to each other. Taken up, to at least one of the outer and inner surfaces of the movable main contact of the nozzle with grooves provided in the circumferential direction of the nozzle, it is characterized by fitting the airtight member having elasticity in the groove.

  According to the present invention, the outer surface of the nozzle and the inner surface of the movable-side main contactor have a fitting structure, a groove is provided in the fitting portion, and an airtight member is fitted in the groove, thereby generating a high pressure generated in the puffer cylinder. Since SF6 gas can be prevented from leaking from the fitting part and causing pressure loss, a puffer cylinder with a smaller diameter can be realized and higher arc extinguishing performance can be achieved. A gas circuit breaker excellent in properties can be provided.

  Hereinafter, typical embodiments of the present invention will be specifically described with reference to FIGS. In addition, since all the basic structures of the following embodiment are the same as that of the conventional gas circuit breaker shown in FIG. 10, the same code | symbol is attached | subjected about the same member and description is abbreviate | omitted.

(1) First Embodiment [Configuration]
As shown in FIG. 1, in the first embodiment, the outer surface of the nozzle 6 and the inner surface of the movable side main contact 4 have a fitting structure that fits each other. A groove 13 is provided along the circumferential direction of the nozzle 6 on the inner surface side of the movable main contact 4 on the fitting surface 12 included in this fitting structure. The feature of the first embodiment is that the O-ring 14 is fitted in the groove 13. The width dimension of the groove 13 is adjusted so that the O-ring 14 is compressed between about 60% and 90% by volume. Further, the O-ring 14 has elasticity so that gas tightness is maintained while being fitted in the groove 13.

[Function and effect]
The operational effects of the first embodiment having the above-described configuration are as follows. That is, since the O-ring 14 that maintains airtightness is present on the fitting surface 12 between the nozzle 6 and the movable main contact 4, gas in the puffer chamber 3 does not leak from the fitting surface 12. . Therefore, the gas pressure in the puffer chamber 3 can be prevented from decreasing, and the nozzle 6 can effectively blow high-pressure gas onto the arc 10. As a result, it is possible to further reduce the size and improve the blocking performance.

(2) Second Embodiment [Configuration]
A second embodiment is shown in FIG. That is, the groove 13 shown in FIG. 2 is slightly deeper than the groove 13 shown in FIG. A Teflon ring 15 made of Teflon is attached between the inner periphery of the O-ring 14 and the fitting surface 12 along the inner periphery of the O-ring 14. As shown in FIG. 3, the Teflon ring 15 is made of a band-shaped member.

[Function and effect]
In the second embodiment, the following functions and effects can be obtained in addition to the functions and effects described above. That is, by attaching the Teflon ring 15 having excellent heat resistance to the inner peripheral portion of the O-ring 14, the gas in the puffer chamber 3 heated to a high temperature by the arc 10 is not directly applied to the O-ring 14. Therefore, the O-ring 14 is not exposed to high-temperature gas, and it is possible to extend the life by suppressing thermal degradation.

(3) Third Embodiment [Configuration]
The third embodiment shown in FIG. 4 has a structural feature in that wave plate springs 21 are installed in the circumferential direction instead of the O-ring 14. That is, in the second embodiment, gas sealing is performed by the O-ring 14 and the Teflon ring 15, but in the third embodiment, gas sealing is performed by the corrugated leaf spring 21 and the Teflon ring 15. As shown in FIG. 5, the corrugated spring 21 is configured so as to exert a pressing force on the inside by being crushed in the thickness direction, and the Teflon ring 15 is pressed sufficiently strongly against the fitting surface 12 so as to be gas tight. Is secured.

[Function and effect]
In the third embodiment as described above, in addition to the function and effect of the second embodiment, the corrugated leaf spring 21 has higher heat resistance than the O-ring 14, so there is no fear of thermal degradation. It has unique effects such as increased durability.

(4) Fourth Embodiment [Configuration]
As shown in FIG. 6, in the fourth embodiment, the fitting surface 12 between the nozzle 6 and the movable main contact 4 is provided with a portion 16 having a small nozzle outer diameter and a portion 17 having a large nozzle outer diameter, and a step 35. It is characterized by having formed.

[Function and effect]
In the fourth embodiment described above, by providing the fitting surface 12 with the step 35, the gas pressure from the puffer chamber 3 is not directly applied to the fitting surface 12, and gas leakage can be reliably prevented. . In addition, since it is not necessary to provide the O-ring 14, the number of parts can be reduced, and the manufacturing cost can be reduced.

(5) Fifth Embodiment [Configuration]
In the fifth embodiment shown in FIG. 7, a screw 18 is formed on the fitting surface 12, and the outer surface of the nozzle 6 and the inner surface of the movable main contact 4 are fixed with the screw 18. Strictly speaking, the extremely narrow gaps are spirally connected to each other by the screw 18, but the hot gas from the puffer chamber 3 acts on this portion for several tens of milliseconds at most. It is unlikely that gas will escape through the gaps in the screws 18 in such a short time, and in effect it may be considered as an airtight structure.

[Function and effect]
In the fifth embodiment in which the nozzle 6 and the movable main contact 5 are fastened by the screw 18, the work efficiency of assembly is good by the amount fastened by the screw, and the number of parts is small, which is advantageous in terms of cost. There is a merit such as.

(6) Sixth Embodiment [Configuration]
As shown in FIG. 8, in the sixth embodiment, the fitting surface 12 is divided into two in the axial direction, and the outer diameter is approximately equal to the outer diameter of the nozzle 6 at the puffer cylinder 2 side, that is, at the base end portion of the nozzle 6. A metal base 19 having the following is attached. The metal base 19 is assembled by press-fitting both the outer diameter and the inner diameter of the movable main contact 4 so as to be an interference fit. The metal base is made of a metal member having a lower hardness than the movable main contact 4.

[Function and effect]
Conventionally, since an excessive force is applied to the nozzle 6 which is an insulator, the assembly method called press-fitting has been avoided, but it is also possible to assemble by press-fitting in order to prevent the gas leakage pointed out in the above problems. However, when the nozzle 6 is press-fitted and assembled, depending on the nature and amount of the filler in the nozzle material, the amount of elastic deformation is small and the nozzle may be damaged without being able to withstand the press-fitting.

  Therefore, in the sixth embodiment, the fitting surface 12 of the nozzle 6 is divided into two parts in the axial direction, and a metal base 19 is provided as a member that is press-fitted to the movable main contact 4 side. The workability at the time of press-fitting with the movable main contact 4 is improved. In addition, since the metal base member is manufactured from a metal material, there is an advantage that accuracy in processing the parts can be easily obtained. Furthermore, since the metal base 19 is lower in hardness than the movable main contact 4, it can be prevented from being rubbed with the movable main contact 4 during press-fitting to generate foreign matter or galling. It is possible to ensure time safety.

(7) Seventh Embodiment [Configuration]
The seventh embodiment shown in FIG. 9 is not the metal base 19 used in the sixth embodiment as a base member having an outer diameter substantially equal to the outer diameter of the nozzle 6 attached to the proximal end portion of the nozzle 6. It is characterized by comprising a Teflon base 20 without additives.

[Function and effect]
If the metal base 19 is made of light aluminum, if the aluminum is exposed to the hot gas from the puffer chamber 3, the melting point of the aluminum is extremely easy because it has a low melting point and is easily mixed into the gas. There is a risk of significantly reducing insulation. However, if the metal base 19 is made of an iron or copper material having a high melting point, the heat resistance is excellent, but the weight increases. Since the metal base 19 is included in the movable portion, a slight increase in weight causes problems such as a decrease in opening / closing speed and insufficient operating force.

  In order to avoid such a problem, in the seventh embodiment, the Teflon base 20 is lightweight and does not generate a substance that degrades the insulating performance of the SF6 gas even when exposed to hot gas. A base member is configured. Since the Teflon in this case is pure Teflon containing no additive and has sufficient elasticity, the workability at the time of press-fitting with the movable main contactor 4 is improved as in the sixth embodiment. ing.

(8) Other Embodiments The present invention is not limited to the above-described embodiment, and the material, dimensions, and the like of each member can be changed as appropriate. For example, in the sixth and seventh embodiments, the fitting surface 12 is divided into two in the axial direction and the base member is attached to the base end portion of the nozzle 6. However, the nozzle 6 is usually made of a Teflon material. Therefore, some degree of elastic deformation is possible, and the nozzle 6 and the movable main contact 4 can be directly pressed and assembled without providing a base member.

The figure which shows the structure of 1st Embodiment which concerns on this invention. The figure which shows the structure of 2nd Embodiment which concerns on this invention. The principal part perspective view of 2nd Embodiment. The figure which shows the structure of 3rd Embodiment which concerns on this invention. AA sectional drawing of FIG. The figure which shows the structure of 4th Embodiment which concerns on this invention. The figure which shows the structure of 5th Embodiment which concerns on this invention. The figure which shows the structure of the 6th Embodiment which concerns on this invention. The figure which shows the structure of the 7th Embodiment which concerns on this invention. The general block diagram of the arc-extinguishing chamber of the conventional puffer type gas circuit breaker. The block diagram for demonstrating the problem in the conventional structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Puffer piston 2 ... Puffer cylinder 3 ... Puffer chamber 4 ... Movable side main contact 5 ... Movable side arc contact 6 ... Nozzle 7 ... Fixed side arc contact 8 ... Fixed side main contact 9 ... Insulating cylinder 10 ... Arc 12 ... Fitting surface 13 ... Groove 14 ... O-ring 15 ... Teflon ring 16 ... Part 17 with a smaller nozzle outer diameter ... Part 18 with a larger nozzle outer diameter ... Screw 19 ... Metal base 20 ... Teflon base 21 ... Wave Leaf spring 31 ... fixed side contact 32 ... movable side contact 33 ... operating rod 34 ... communication hole arrow B ... gas outflow path

Claims (9)

A fixed side contact consisting of a fixed side arc contact and a fixed side main contact and a movable side contact consisting of a movable side arc contact and a movable side main contact can be freely connected and separated in a container sealed with an arc extinguishing gas. A puffer chamber composed of a puffer cylinder and a puffer piston that is slidable in the puffer cylinder is formed at the movable contact, and is arranged at the tip of the puffer cylinder and outside the movable main contactor. A cylindrical nozzle is attached, and the arc extinguishing gas in the puffer cylinder is compressed by the puffer piston during the opening operation, and the nozzle generates the arc extinguishing gas between the arc contacts on the fixed side and the movable side. In the gas circuit breaker configured to spray,
The outer surface of the nozzle and the inner surface of the movable side main contact take a fitting structure that fits each other,
At least one of the outer surface of the nozzle and the inner surface of the movable side main contact is provided with a groove in the circumferential direction of the nozzle,
A gas circuit breaker characterized in that an airtight member having elasticity is fitted in the groove. The airtight member is composed of an O-ring,
The gas circuit breaker according to claim 1, wherein a band-shaped ring mainly composed of tetrafluoroethylene resin is provided inside the O-ring.   The gas circuit breaker according to claim 2, wherein a metal corrugated spring is used in place of the O-ring. A fixed side contact consisting of a fixed side arc contact and a fixed side main contact and a movable side contact consisting of a movable side arc contact and a movable side main contact can be freely connected and separated in a container sealed with an arc extinguishing gas. A puffer chamber composed of a puffer cylinder and a puffer piston that is slidable in the puffer cylinder is formed at the movable contact, and is arranged at the tip of the puffer cylinder and outside the movable main contactor. A cylindrical nozzle is attached, and the arc extinguishing gas in the puffer cylinder is compressed by the puffer piston during the opening operation, and the nozzle generates the arc extinguishing gas between the arc contacts on the fixed side and the movable side. In the gas circuit breaker configured to spray,
The outer surface of the nozzle and the inner surface of the movable side main contact take a fitting structure that fits each other,
A gas circuit breaker comprising a step portion having a large diameter portion and a small diameter portion on an outer surface of the nozzle and the inner surface of the movable side main contactor having the fitting structure. A fixed side contact consisting of a fixed side arc contact and a fixed side main contact and a movable side contact consisting of a movable side arc contact and a movable side main contact can be freely connected and separated in a container sealed with an arc extinguishing gas. A puffer chamber composed of a puffer cylinder and a puffer piston that is slidable in the puffer cylinder is formed at the movable contact, and is arranged at the tip of the puffer cylinder and outside the movable main contactor. A cylindrical nozzle is attached, and the arc extinguishing gas in the puffer cylinder is compressed by the puffer piston during the opening operation, and the nozzle generates the arc extinguishing gas between the arc contacts on the fixed side and the movable side. In the gas circuit breaker configured to spray,
A gas circuit breaker, wherein the nozzle outer surface and the movable main contact inner surface are attached with screws. A fixed side contact consisting of a fixed side arc contact and a fixed side main contact and a movable side contact consisting of a movable side arc contact and a movable side main contact can be freely connected and separated in a container sealed with an arc extinguishing gas. A puffer chamber composed of a puffer cylinder and a puffer piston that is slidable in the puffer cylinder is formed at the movable contact, and is arranged at the tip of the puffer cylinder and outside the movable main contactor. A cylindrical nozzle is attached, and the arc extinguishing gas in the puffer cylinder is compressed by the puffer piston during the opening operation, and the nozzle generates the arc extinguishing gas between the arc contacts on the fixed side and the movable side. In the gas circuit breaker configured to spray,
A gas circuit breaker characterized in that an outer diameter of the nozzle and an inner diameter of the movable main contactor are set to be an interference fit, and both are press-fitted and assembled. A fixed side contact consisting of a fixed side arc contact and a fixed side main contact and a movable side contact consisting of a movable side arc contact and a movable side main contact can be freely connected and separated in a container sealed with an arc extinguishing gas. A puffer chamber composed of a puffer cylinder and a puffer piston that is slidable in the puffer cylinder is formed at the movable contact, and is arranged at the tip of the puffer cylinder and outside the movable main contactor. A cylindrical nozzle is attached, and the arc extinguishing gas in the puffer cylinder is compressed by the puffer piston during the opening operation, and the nozzle generates the arc extinguishing gas between the arc contacts on the fixed side and the movable side. In the gas circuit breaker configured to spray,
A base member having an outer diameter substantially equal to the outer diameter of the nozzle is attached to the base end of the nozzle,
A gas circuit breaker characterized in that an outer diameter of the base member and an inner diameter of the movable main contactor are set to be an interference fit, and both are press-fitted and assembled.   The gas circuit breaker according to claim 7, wherein a metal material having a hardness lower than that of the movable main contact is used as the base.   The gas circuit breaker according to claim 7, wherein tetrafluoroethylene resin containing no filler is used as the base.

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