Overpressure relief device for switchgear

Abstract

To provide an overpressure safety valve for a pressure barrier plate in a switching device.SOLUTION: Safety valve for a pressure barrier plate (7) of a gas-insulated switchgear, comprising a longitudinal sleeve (2) extending along an axis and having a first end and a second end (25), and a pin (1) extending in the sleeve between a first end (11) and a second end (13), the pin (1) comprising: Wherein the first end portion (11) of the pin carries a first end cap (10), the second end portion (13) of the pin comprises a pin (1) carrying a second end cap (3), a first compression spring (4) in a first section within the sleeve, and a second compression spring (5) in a second section within the sleeve, wherein the first spring (4) and the second spring (5) respectively push the second end cap and the first end cap towards opposite directions along the axis.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an overpressure safety valve for a pressure barrier plate in a switchgear device. [Background technology]

[0002] In switchgear, barrier plates are typically mounted between two metal flanges (one flange and one opposing flange). In this configuration, they can withstand the design pressure. During assembly and transportation, barrier plates mounted on one flange without an opposing flange can be used. This significantly reduces the pressure resistance. In this transportation configuration, the maximum allowable pressure is defined by the design. If excessive pressure is applied for any reason, which is not a normal process but can occur due to some kind of malfunction, the barrier plates may be damaged.

[0003] Prior art solutions utilize an additional flange ring to hold the plate so that it can maintain its full design pressure. This flange ring has a significant negative impact on the layout and cost of the switchgear. In fact, this additional ring is attached to a flange, and the barrier plate is held between the flange and the additional ring. A second flange is then placed on top. Such an additional ring is expensive and directly impacts the dimensions in the substation layout.

[0004] Therefore, there is a need for a new method and a new device for ensuring the gas-tightness and / or mechanical resistance of a pressure barrier plate of a switchgear during transportation of said switchgear. Summary of the Invention

[0005] The present invention first relates to a safety valve for a pressure barrier plate of gas-insulated switchgear, comprising: a longitudinal sleeve extending along an axis (AA') and having a first end and a second end; a pin extending within the sleeve between the first and second ends, the first end of the pin carrying a first end cap and the second end of the pin carrying a second end cap; a first compression spring in a first compartment within the sleeve; and compression means, such as a second compression spring or an O-ring, in a second compartment within the sleeve, wherein the first spring and the compression means respectively press the second end cap and the first end cap in opposite directions along the axis (AA').

[0006] The present invention is safer than conventional solutions at similar cost.

[0007] The present invention is non-destructive (components cannot be damaged by overpressure events and components cannot be damaged in the transportation process of gas-insulated switchgear) and does not require additional work on different components after overpressure has been applied.

[0008] The present invention prevents potential damage to components due to mishandling.

[0009] The safety valve according to the invention may comprise an inner wall of the sleeve, perpendicular to said axis (AA') and separating the inner volumes of the sleeve in said first and second compartments.

[0010] In the safety valve according to the present invention, the first end cap comprises: a first portion having a first diameter (D1) equal to the inner diameter of the first end of the sleeve, and a second portion having a second diameter (D2) greater than D1; The first portion of the first end cap may be fitted to the first end of the sleeve, and / or may further comprise a throat for receiving an O-ring or sealing gasket compressed between the first portion of the cap and the inner wall of the sleeve.

[0011] In the safety valve according to the present invention, the first end cap and / or the second end cap may extend outside the sleeve.

[0012] The invention also relates to a pressure barrier plate comprising at least one safety valve according to the invention.

[0013] The present invention also relates to a gas-insulated switchgear including a pressure barrier plate according to the present invention, wherein the bottom of the safety valve faces a first flange defining a first insulating gas compartment, and the inner housing of the first flange is defined by an inner lip and is capable of receiving the bottom edge of the barrier plate.

[0014] In the gas-insulated switchgear according to the present invention, the top of the safety valve can face a second flange defining a second insulating gas compartment, and the safety valve is isolated on both sides by the flanges. The inner housing of the second flange is defined by an inner lip and can receive the upper end of the barrier plate.

[0015] The present invention also relates to a method for transporting a gas-insulated switchgear according to the invention as described above and elsewhere in this application, comprising: removing the second flange; transporting the gas-insulated switchgear from one location to another, the safety valve acting as an overpressure safety valve for the first insulating gas compartment; reattaching the second flange to the gas-insulated switchgear; The present invention relates to a method, including:

[0016] In the method according to the present invention, Under a certain predetermined pressure in the first insulating gas compartment, the first compression spring may remain in its initial state and a sealing gasket will remain in place between the first end cap and the sleeve; and / or above the predetermined pressure in the first insulating gas compartment, the first compression spring can compress and the compression means, e.g., the second compression spring or the O-ring, can expand, causing the pin to move with its first end cap, insulating gas in the gas compartment to flow to the outside atmosphere, and pressure in the gas compartment to decrease. The compression means, e.g., the second compression spring or the O-ring, is not required for the valve to function, but instead ensures electrical connection between the first part and the second flange when the opposing flanges are attached.

[0017] In the method according to the invention, when the pressure in the first insulating gas compartment decreases, the compression means, for example a second compression spring or an O-ring, can compress and the first compression spring can expand to push the second end cap towards the gas compartment, thereby returning the second end cap to its original position.

[0018] After reinstalling the second flange on the gas-insulated switchgear, the valve is shut off, preventing unwanted gas release from one compartment to another. [Brief explanation of the drawings]

[0019] [Figure 1] 1 shows an embodiment of a safety valve according to the invention in a conveying configuration; [Figure 2] 1 shows an embodiment of a safety valve according to the present invention in an operating configuration; DETAILED DESCRIPTION OF THE INVENTION

[0020] The safety valve according to the invention is shown in FIG. 1 in a conveying configuration.

[0021] The safety valve comprises a longitudinal sleeve 2 extending along an axis AA'. An axial pin 1 extends inside the sleeve along the axis AA' between a first end 23 (see also Figure 2), or upper end, of the sleeve and a second end 25, or lower end, of the sleeve.

[0022] The first end 11, or upper end, of the pin forms or is terminated by a first cap 10 (the cap 10 and the pin body 1 can form a single piece). The cap has a first portion with a first diameter D1, whereby the first portion fits into the first end 23 of the sleeve 2 (e.g., D1 equals the inner diameter of the first end 23), and a second portion with a second diameter D2 greater than D1. The first portion further comprises a throat for receiving an O-ring or sealing gasket 6, which is compressed between the first portion of the cap 10 and the inner wall 21 of the sleeve. The second portion of the cap 10 extends outside the sleeve 2. Alternatively, sealing can be achieved by an axial sealing member.

[0023] The second end 13, or lower end, of the pin forms or is terminated by a second cap 3, e.g., a nut, which may have a single outer diameter D3 (e.g., D3 equal to the inner diameter of the sleeve 2) to fit into the second end 25 of the sleeve 2. In the delivery configuration of Figure 1, part of the cap 3 may extend outside the sleeve 2.

[0024] The inner wall 27 of the sleeve, perpendicular to its axis (AA'), divides the internal volume of the sleeve into two compartments 28, 29, each housing a spring 4 (so-called counter spring), 5 (so-called contact spring), preferably a compression spring; in a variant, an O-ring, or more generally a compression means, can be used instead of the contact spring 5. The contact function can be optional, depending on the need for and / or need for earthing of the valve. A pin 1 passes through a hole 26 in said wall 27.

[0025] The sleeve with its housing and springs 4, 5 resides within a bore in an insulating barrier plate 7 (or bulkhead or supporting insulator) between an insulating gas compartment 20 and the external atmosphere 24 (usually air) within a pressure vessel 8. An inner housing 81 of the flange defined by an internal lip 82 receives the bottom end 71 of the barrier plate 7.

[0026] The spring 4 is in compression between the wall 27 and the second cap 3 which is pressed by the pressure of the gas in said gas compartment 20 .

[0027] Compression means, for example a spring 5 , are in compression between the wall 27 and the first cap 10 .

[0028] 1, the valve acts as an overpressure relief valve for the gas compartment 20. Under a certain predetermined pressure in the compartment 20 (pressure difference across the barrier plate 7), the spring 4 remains in its initial state, thus ensuring that the sealing gasket 6 remains properly in place between the cap 10 and the sleeve 2.

[0029] When the predetermined pressure in the gas compartment 20 is exceeded, the opposing spring 4 is compressed and the spring 5 expands, causing the pin together with its first cap 10 and gasket 6 to move upwards and eventually lose contact with the sleeve 2.

[0030] At this point, the insulating gas within the gas compartment 20 flows to the external atmosphere 24, causing the pressure in the gas compartment 20 to decrease.

[0031] Then, when the pressure in the gas compartment 20 drops below a predetermined pressure, the spring 5 can be compressed again and the spring 4 can be expanded again, pushing the second cap 3 towards the gas compartment 20, thereby returning the first cap 10 and gasket 6 to their original positions, i.e., the gas compartment 20 is again sealed from the external atmosphere 24.

[0032] 2 (operating configuration), the same insulating barrier plate 7 provides insulation between an insulating gas compartment 20 in pressure vessel 8 and another insulating gas compartment 22 in pressure vessel 9 (assembled with pressure vessel 8). A portion or lip 91 of flange 9 blocks first end 11 of pin 1. A side housing 93 of said flange 9, defined by an internal lip 92, receives upper end 73 of barrier plate 7.

[0033] The valve is therefore blocked or prevented from moving on either side by flanges 8, 9 of each pressure vessel, or more precisely by lips 81, 91, in the embodiment shown in Figures 1 and 2. A separation or partition is therefore formed between the two insulating gas compartments 20, 22.

[0034] According to the invention, the valve is blocked by two flanges 8, 9 and only functions when only one (bottom) flange 8 is applied, as described above in the conveying arrangement.

[0035] The valve according to the invention therefore relieves overpressure in the conveying configuration (Fig. 1) whilst remaining tight in the mounted configuration between two flanges 8, 9 (Fig. 2).

[0036] Several valves according to the invention can be used on the same barrier plate 7 . [Explanation of symbols]

[0037] 1 Axial Pin 2 longitudinal sleeves 3 Second cap / Second end cap 4 Opposing spring / first compression spring 5 Contact spring / secondary compression spring 6 Sealing gasket 7. Insulation barrier plate / pressure barrier plate 8 Pressure vessel / first flange 9 Pressure vessel / second flange 10 First cap / first end cap 11 first end 13 Second end 20 Insulating gas compartment / first insulating gas compartment 21 Inner wall 22 Insulating gas compartment / second insulating gas compartment 23 First end 24 External atmosphere 25 Second end 26 holes 27 Inner wall 28 Sections / First Section 29th section / Second section 71 Bottom end 73 Upper end 81 Inner housing / lip 82 Inner lip 91 Lip / inner housing 92 Inner lip 93 Side housing D1 First diameter D2 Second diameter D3 Single outer diameter AA' axis

Claims

1. A safety valve for a pressure barrier plate (7) of gas-insulated switchgear, comprising: a longitudinal sleeve (2) extending along an axis (AA') and having a first end (23) and a second end (25); and a pin (1) extending within the sleeve (2) between a first end (11) and a second end (13), the first end (11) of the pin (1) carrying a first end cap (10), and the second end (13) of the pin (1) carrying a second end cap (11). a pin (1) carrying two end caps (3), a first compression spring (4) in a first section (28) in said sleeve (2), and a second compression spring (5) in a second section (29) in said sleeve (2), said first spring (4) and said second spring (5) respectively pushing said second end cap (3) and said first end cap (10) in opposite directions along said axis (AA').

2. 2. The safety valve according to claim 1, wherein an inner wall (27) of the sleeve (2) is perpendicular to the axis (AA') and separates the internal volume of the sleeve (2) into the first compartment (28) and the second compartment (29).

3. 3. The safety valve according to claim 1, wherein the first end cap (10) has at least a first portion having a first diameter (D1) to fit into the first end (23) of the sleeve (2).

4. 4. The safety valve of claim 3, wherein the first end cap (10) has a second diameter (D2) greater than D1.

5. 5. The safety valve of claim 3 or 4, wherein the first portion of the first end cap (10) further comprises a throat for receiving an O-ring or sealing gasket (6) compressed between the first portion of the cap (10) and the inner wall (21) of the sleeve (2).

6. 5. A safety valve according to any one of claims 1 to 4, wherein the first end cap (10) and / or the second end cap (3) can extend outside the sleeve (2).

7. A pressure barrier plate (7) comprising at least one safety valve according to any one of claims 1 to 6.

8. 8. Gas-insulated switchgear comprising a pressure barrier plate (7) according to claim 7, wherein the bottom of the safety valve faces a first flange (8) that defines a first insulating gas compartment (20).

9. 9. Gas-insulated switchgear according to claim 8, wherein the inner housing (81) of the first flange (8) is defined by an inner lip (82) and receives the bottom end (71) of the barrier plate (7).

10. 10. The gas-insulated switchgear according to claim 8 or 9, wherein a top of the safety valve faces a second flange (9) that defines a second insulating gas compartment (22), and the safety valve is blocked on both sides by the flanges (8, 9).

11. 11. Gas-insulated switchgear according to claim 10, wherein the inner housing (91) of the second flange (9) is defined by an inner lip (92) and receives the upper end (73) of the barrier plate (7).

12. A method for transporting a gas-insulated switchgear according to claim 10 or 11, comprising the steps of: Removing the second flange (9); transporting the gas-insulated switchgear from one location to another, the safety valve acting as an overpressure safety valve for the first insulating gas compartment (20); Reattaching the second flange (9) to the gas-insulated switchgear; A method comprising:

13. Under a certain predetermined pressure in the first insulating gas compartment (20), the first compression spring (4) remains in its initial state and the sealing gasket (6) remains in a predetermined position between the first end cap (10) and the sleeve (2); When the predetermined pressure in the first insulating gas compartment (20) is exceeded, the first compression spring (4) is compressed and the second compression spring (5) expands, causing the pin (1) to move with its first end cap (10), and the insulating gas in the gas compartment (20) flows to the external atmosphere (24), causing the pressure in the gas compartment (20) to decrease. The method of claim 12.

14. 14. The method of claim 13, wherein when the pressure in the gas compartment (20) decreases, the second compression spring (5) is compressed and the first compression spring (4) expands to push the second end cap (3) towards the gas compartment (20), thereby returning the first end cap (10) to its original position.

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