Vacuum interrupter with vacuum device shield

Abstract

The vacuum interrupter includes a nominally cylindrical insulator having a first insulating portion and a second insulating portion with a gap defined between them, and a nominally cylindrical vapor shield having a first ring with a plurality of spaced bobbles and a second ring with a plurality of spaced bobbles. A gap ring, including a series of spaced notches facing the vapor shield, is positioned within the gap. The bobbles in the first and second rings are configured such that the bobbles in the second ring pass through the notches in the gap ring and the bobbles in the first ring rest on the gap ring.

Description

Technical Field

[0001] The present disclosure generally relates to a vacuum interrupter including a vapor shield.

Background Art

[0002] A power supply network is often referred to as a power system and usually includes a plurality of power plants each having a generator such as a gas turbine, a nuclear reactor, a coal-fired generator, a hydroelectric dam, etc. The power plants supply power at various medium voltages, which is then boosted to a high-voltage alternating current signal by a transformer and connected to a high-voltage transmission line. This high-voltage transmission line usually supplies power to a substation located within the area, where the voltage is stepped down to a medium voltage for distribution. The substation supplies medium-voltage power to a three-phase feeder line including three single-phase feeder lines that carry the same current but are 120 degrees out of phase. Three-phase and single-phase lateral lines branch from feeder lines that supply medium voltage to various distribution transformers. In the distribution transformers, the voltage is stepped down to a low voltage and supplied to loads such as homes and businesses.

[0003] A power supply network of the type mentioned above usually includes switching devices, breakers, reclosing devices, current interrupters, etc. that control the flow of power through the network. A vacuum interrupter is a switch designed to withstand relatively high power and has a specific application for many of these types of devices. A vacuum interrupter includes opposing contacts disposed within a vacuum enclosure, one of which is a fixed contact and the other is a movable contact. When the vacuum interrupter is opened by moving the movable contact away from the fixed contact to interrupt the flow of current through the interrupter, a plasma arc that rapidly extinguishes in a vacuum occurs between the contacts at the next zero current crossing, at which time metal vapor is released from the contacts. The contacts separated in a vacuum provide an insulation withstand voltage that exceeds the voltage of the power system and prevent the flow of current. The vacuum interrupter housing is an insulator that supports the contact structure and is usually ceramic, providing insulation withstand voltage.

[0004] After the vacuum interrupter's opening cycle, the metal vapor released by the arc forms a conductive metal film on the inner surface of the insulating housing, creating a conductive path around the contact, thus preventing the vacuum interrupter from functioning properly. Therefore, in many vacuum interrupter designs, an annular vapor shield is provided at a central position between the contact and the insulating housing, i.e., not extending along the entire length of the insulating housing, and the upper and lower ends of this shield may be bent toward the contact so that the metal vapor is collected on the shield rather than inside the insulating housing. [Overview of the Initiative]

[0005] The following description discloses and describes a vacuum interrupter comprising a nominally cylindrical insulator having a first insulating portion and a second insulating portion with a gap defined between them, and a nominally cylindrical vapor shield having a first ring with a plurality of spaced bobbles and a second ring with a plurality of spaced bobbles. A gap ring having a series of spaced notches facing the vapor shield is positioned within the gap. The bobbles in the first and second rings are configured such that the bobbles in the second ring pass through the notches in the gap ring and the bobbles in the first ring rest on the gap ring.

[0006] Further features of this disclosure will become apparent from the following description and the attached claims, in conjunction with the attached drawings. [Brief explanation of the drawing]

[0007] [Figure 1] This is a cutaway perspective view of a portion of a vacuum interrupter showing a known vapor shield. [Figure 2] This is a cutaway perspective view of a portion of a vacuum interrupter, showing another known vapor shield. [Figure 3]This is a partial cutaway perspective view of a vacuum interrupter showing a vapor shield including a ring with a notched opening and aligned upper and lower bobbles. [Figure 4] Figure 3 is a plan view of a ring with a notched section separated from the vacuum interrupter shown. [Figure 5] This is a partially cutaway perspective view of a vacuum interrupter showing a vapor shield that includes a ring with a notched opening and more upper bobbles than lower bobbles. [Figure 6] This is a partial cutaway perspective view of a vacuum interrupter that includes a vapor shield having a ring with a notched opening and radially offset upper and lower bobbles. [Modes for carrying out the invention]

[0008] The following description of embodiments of the present disclosure is directed toward a vacuum interrupter comprising divided insulating portions, a single-piece vapor shield, and a ring having a notched section positioned between the insulating portions, wherein a bobble in the lower shield portion passes through the notched section and a bobble in the upper shield portion rests on the ring, but this is merely illustrative and is not intended to limit the present disclosure or its applications or uses.

[0009] Figure 1 is a cutaway perspective view of a portion of a vacuum interrupter 10, including an upper nominal cylindrical ceramic insulator 12 and a lower nominal cylindrical ceramic insulator 14, with a gap 16 defined between them, and a vacuum chamber 18 provided within the insulators 12 and 14, with a fixed contact and a movable contact (not shown) provided within the chamber 18. These and other parts of the vacuum interrupter 10 are not shown for clarity, but their positions and operations will be well understood by those skilled in the art. The vacuum interrupter 10 also includes a cylindrical vapor shield 20 positioned within the chamber 18, facing the inner surfaces of the insulators 12 and 14, which functions to capture metallic vapors released when the contacts separate and the vacuum interrupter 10 opens, preventing the formation of a metallic film on the insulators 12 and 14 and the formation of conductive paths around the separated contacts. In this known design, the vapor shield 20 includes an upper cylindrical portion 22 and a lower cylindrical portion 24 brazed or welded to each other along a seam 26, the lower portion 24 including a flange ring 28 positioned within the gap 16. The vapor shield 20 may be manufactured from any suitable material such as copper or steel. The upper portion 22 includes a bobble 30 that seats in a recess (not shown) of the upper insulator 12 to provide axial positioning of the upper portion 22 with respect to the central axis of the vacuum interrupter 10 and the insulator 12, and the lower portion 24 includes a bobble 32 that seats in a recess (not shown) of the lower insulator 14 to provide axial positioning of the lower portion 24 with respect to the central axis of the vacuum interrupter 10 and the insulator 14. As used herein, a bobble is a feature formed on the shield that has a larger pitch circle diameter (PCD) than the shield body and functions to radially position the shield with respect to the upper portion 22 and the lower portion 24.

[0010] Figure 2 is a cutaway perspective view of a portion of the vacuum interrupter 40, with the same reference numerals used for elements similar to those in the vacuum interrupter 10. In this known design, the vapor shield 20 is replaced by a vapor shield 42, which includes a single-piece cylindrical tube 44 formed on the inner surfaces of the upper insulator 12 and the lower insulator 14. An L-shaped annular ring 46 is brazed or welded to the tube 44 and positioned within the gap 16. The shield 42 is axially positioned relative to the insulators during assembly using an external fixture (not shown).

[0011] By improving the design of the steam shield, it is possible to make the shield a single component and eliminate the need for external fixtures for axial alignment of the steam shield. Figure 3 is a cutaway perspective view of a portion of the vacuum interrupter 50, with the same reference numerals used for elements similar to those in the vacuum interrupter 10. In this configuration, the vapor shield 20 is replaced by a vapor shield 52 which includes an upper ring 54 with spaced bobbles 56 and a lower ring 58 with spaced bobbles 60, with each bobble 56 in the upper ring 54 axially aligned with the bobbles 60 in the lower ring 58. The vacuum interrupter 50 also includes a ring 62 which is located within a gap 16 and has spaced notched notches 64 facing the vapor shield 52. Figure 4 is a plan view of the ring 62 separated from the vacuum interrupter 50. The spacing and number of the notched notches 64 correspond to the spacing and number of the bobbles 56 in the upper ring 54 and the spacing and number of the bobbles 60 in the lower ring 58. During the assembly of the vacuum interrupter 50, the ring 62 is positioned and fixed within the gap 16, and the vapor shield 52 is slid into the chamber 18, so that the bobbles 56 and 60 are aligned with the notched notches 64. After the bobble 60 of the lower ring 58 has passed through the notched notch 64, but before the bobble 56 of the upper ring 54 has passed through the notched notch 64, the vapor shield 52 is rotated by a certain angle so that the bobbles 56 and 60 are axially aligned with the recesses (not shown) of the upper and lower cylindrical insulators 12 and 14. The shield 52 is placed in contact with the portion of the ring 62 where the bobble 56 does not have a notched notch 64, and is further inserted into the chamber 18 until the bobbles 56 and 60 are seated in the recesses. The vapor shield 52 is then brazed or welded to the ring 62.

[0012] The terms upper ring and lower ring are used herein to mean that the bobble 56 in ring 54 and the bobble 60 in ring 58 are positioned on an axial plane. However, in certain embodiments, the bobble 60 in the lower or second ring may be offset from each other axially, and not all may be in the same axial plane. The intention is that in these embodiments, the bobble 60 is still defined as a ring of bobbles. Furthermore, in this non-limiting embodiment, there may be four equally spaced notches 64 and bobbles 56 and 60, and the vapor shield 52 may be rotated by 45 degrees. However, other numbers of notches and bobbles, such as any number between 3 and 10, may also be appropriate.

[0013] Figure 5 is a cutaway perspective view of a portion of the vacuum interrupter 70, with the same reference numerals used for elements similar to those in the vacuum interrupter 50. In this configuration, the vapor shield 50 includes an upper ring 54 with spaced bobbles 56 and a lower ring 58 with spaced bobbles 60, but the upper ring 54 is replaced by a vapor shield 72 which has more or additional bobbles 74 than the bobbles 60 and notched notches 64 in the lower ring 58. In other words, the vapor shield 72 still includes axially aligned bobbles 56 and 60, but the additional bobbles 74 do not have corresponding bobbles or notched notches 64 in the lower ring 58. Thus, because the additional bobbles 74 are placed on the ring 62, there is no need to rotate the shield 72 after the bobbles 60 of the lower ring 58 have passed through the notched notches 64. Appropriate recesses (not shown) are provided at appropriate locations on the insulators 12 and 14, and the bobbles 56, 60 and 74 are placed within these recesses.

[0014] Figure 6 is a cutaway perspective view of a portion of the vacuum interrupter 80, where elements similar to those of the vacuum interrupter 50 are given the same reference numerals. In this configuration, the vapor shield 50 includes an upper ring 54 with spaced bobbles 56 and a lower ring 58 with spaced bobbles 60, but the bobbles 56 and 60 are not axially aligned with each other and are replaced by a vapor shield 82 defined herein as being radially offset. Thus, since the bobbles 56 rest on the ring 62, it is not necessary to rotate the shield 82 after the bobbles 60 of the lower ring 58 pass through the cutaway notch 64. Appropriate recesses (not shown) are provided at appropriate locations on the insulators 12 and 14, and the bobbles 56 and 60 are placed within the recesses.

[0015] The above description discloses and illustrates only exemplary embodiments of the present disclosure. Those skilled in the art will readily recognize from such description and from the accompanying drawings and claims that various changes, modifications, and variations can be made without departing from the spirit and scope of the present disclosure as defined in the following claims.

Claims

1. It is a vacuum interrupter, A nominally cylindrical insulator comprising a first insulating portion and a second insulating portion, wherein a gap is defined between the first insulating portion and the second insulating portion, A nominal cylindrical vapor shield comprising a first ring having multiple spaced bobbles and a second ring having multiple spaced bobbles, A vacuum interrupter comprising: a gap ring disposed within the gap and including a series of spaced notches facing the vapor shield, wherein a plurality of bobbles in first and second rings having bobbles are configured such that the bobbles in the second ring pass through the notches in the gap ring and the bobbles in the first ring rest on the gap ring.

2. The vacuum interrupter according to claim 1, wherein each bobble in the first ring having the bobble is located in a recess in the first insulating portion, and each bobble in the second ring having the bobble is located in a recess in the second insulating portion.

3. The vacuum interrupter according to claim 1, wherein each bobble in a first ring having the bobble is axially aligned with the bobble in a second ring having the bobble, and the vapor shield is assembled by inserting the vapor shield into the insulator such that the bobble of the second ring passes through the notched notch in the gap ring, and rotating the vapor shield before the bobble in the first ring passes through the notched notch in the gap ring.

4. The vacuum interrupter according to claim 1, wherein each bobble in the second ring having the bobble is axially aligned with the bobble in the first ring having the bobble, and the first ring having the bobble contains more bobble than the second ring having the bobble.

5. The vacuum interrupter according to claim 1, wherein each bobble in the first and second rings having the bobble is radially offset from one another.

6. The vacuum interrupter according to claim 1, wherein all of the bobbles in the second ring having the bobbles are arranged on an axial plane.

7. The vacuum interrupter according to claim 1, wherein the gap ring is brazed or welded to the vapor shield.

8. The vacuum interrupter according to claim 1, wherein the number of notches and bobbles in the second ring is in the range of 3 to 10.

9. The vacuum interrupter according to claim 8, wherein the number of bobbles in the notched notch and the second ring is four.

10. The vacuum interrupter according to claim 1, wherein the vapor shield is a single-component vapor shield.

11. It is a vacuum interrupter, A nominally cylindrical insulator comprising a first insulating portion and a second insulating portion, wherein a gap is defined between the first insulating portion and the second insulating portion, A nominally cylindrical vapor shield comprising a first ring having multiple spaced bobbles and a second ring having multiple spaced bobbles, wherein each bobble in the first and second rings is radially offset from one another, and the vapor shield, A vacuum interrupter comprising: a gap ring disposed within the gap and including a series of spaced notches facing the vapor shield, wherein the number of bobbles in the second ring is equal to the number of notches in the gap ring.

12. The vacuum interrupter according to claim 11, wherein each bobble in the first ring having the bobble is located in a recess in the first insulating portion, and each bobble in the second ring having the bobble is located in a recess in the second insulating portion.

13. The vacuum interrupter according to claim 11, wherein the gap ring is brazed or welded to the vapor shield.

14. The vacuum interrupter according to claim 11, wherein the number of notches and bobbles in the second ring is in the range of 3 to 10.

15. The vacuum interrupter according to claim 14, wherein the number of notches and bobbles in the second ring is four.

16. The vacuum interrupter according to claim 11, wherein the vapor shield is a single-component vapor shield.

17. It is a vacuum interrupter, A nominally cylindrical insulator comprising a first insulating portion and a second insulating portion, wherein a gap is defined between the first insulating portion and the second insulating portion, A nominal cylindrical vapor shield of a single component, comprising a first ring having multiple spaced bobbles and a second ring having multiple spaced bobbles, A vacuum interrupter comprising: a gap ring disposed within the gap and including a series of spaced notches facing the vapor shield, wherein each bobble in the first ring having bobbles is disposed in a recess in the first insulating portion, and each bobble in the second ring having bobbles is disposed in a recess in the second insulating portion.

18. The vacuum interrupter according to claim 17, wherein each bobble in a first ring having the bobble is axially aligned with the bobble in a second ring having the bobble, and the vapor shield is assembled by inserting the vapor shield into the insulator such that the second ring having the bobble passes through the notched notch in the gap ring, and rotating the vapor shield before the bobble in the first ring passes through the notched notch in the gap ring.

19. The vacuum interrupter according to claim 17, wherein each bobble in the second ring having the plurality of bobbles is axially aligned with the bobbles in the first ring having the plurality of bobbles, and the first ring having the plurality of bobbles contains more bobbles than the second ring having the plurality of bobbles.

20. The vacuum interrupter according to claim 17, wherein each bobble in the first and second rings having the bobble is radially offset from one another.

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