JPH11345717A - Automatic restoration type bursting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic restoration type bursting device for an oil filled transformer capable of reducing shocks at the time of operation, reducing requirement for shock resistance even when the size of the device is increased and suppressing the increase of weight. SOLUTION: The pressure of a casing 321 connected to a tank for an oil filled transformer is raised due to short-circuit between winding layers or the like. When the pressure rise is detected by a pressure detector 351, a trigger valve 352 is opened and an expansion room 329 is opened to atmosphere, a valve member 328 is depressed by the pressure of oil in the casing 321 to contract the room 329. Then the valve member 328 is separated from a valve seat 323 and allows oil in the casing 321 to flow out to ease pressure rise. When a ratio differential relay or the like is driven and the oil filled transformer is separated from an electric route, the pressure is dropped, the trigger valve 352 is closed and the room 329 tries to be restored and expanded by the elastic force of a bellows 327. The speed of restoration, i.e., the moving speed of the valve member 328, is controlled by the flow rate of oil passing a nozzle 326 to prevent the generation of shocks due to a water hammer phenomenon or collision with the valve seat 323.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an automatic reset type pressure relief device used for an oil-filled electric device such as an oil-filled transformer.

[0002]

2. Description of the Related Art In oil-immersed transformers and the like, an automatic reset type pressure-release device, which is a type of pressure-release device, is mounted to alleviate abnormal internal pressure caused by interlayer short-circuit between coils. An automatic return type pressure relief device is used to prevent unnecessary oil leakage during operation. As a conventional automatic return type pressure release device, for example, Japanese Patent Application Laid-Open No. 54-125
No. 435 and Japanese Utility Model Application Laid-Open No. 61-188327 disclose a pressure relief device. These devices do not have a means for adjusting the operating speed of the valve member at the time of opening and closing to mitigate the shock at the time of operation, and there is a water hammer phenomenon due to sudden opening and closing and a collision of the valve member with the valve seat. Impact occurs. Hereinafter, FIGS.
A conventional automatic return type pressure release device will be described with reference to FIG. 7 is an attached state diagram showing a state where the pressure relief device is attached, FIG. 8 is a configuration diagram of the pressure relief device, and FIG. 9 is an explanatory diagram for explaining the operation.

[0003] In these figures, an oil-immersed transformer includes a transformer main body 11 having a cylindrical mounting flange portion 11a provided on an upper portion, and a conservator 1 also mounted on an upper portion.
2. It has a pressure relief device 13 that is mounted in communication with the mounting flange 11a. The pressure relief device 13 is connected to the transformer main body 11.
Is of an automatic reset type, which automatically returns when the internal pressure of the sensor drops. The detailed operation will be described later.

As shown in FIG. 8, a detailed configuration of the pressure relief device 13 is provided with a cylindrical valve seat 16 facing the mounting flange 11a.
Is fixed to the mounting flange 11a. A short fence-shaped support plate 17 is welded to a lower end portion inside the valve seat portion 16.

[0005] The valve member 18 has a circular deep dish shape,
The rod 19 is mounted so as to cover the support plate 6 and is attached to the center of the inside of the rod 19 through the support plate 17 from below the support plate 17. The rod 19 is welded to the valve member 18 with the coil spring 20 compressed between the enlarged end and the support plate 17. Then, the valve seat 16, the support plate 17, the valve member 18, the rod 1
9. The pressure release device 13 is constituted by integrating the coil spring 20. Then, the valve seat portion 16 is attached to the mounting flange portion 11.
a to the transformer main body 1
It is attached to 1.

Next, the operation will be described. Normally, the valve member 18 is pressed against the valve seat 16 by the restoring force of the coil spring 20, and the space between the valve seat 16 and the valve member 18 is oil-tightly sealed. When the internal pressure of the transformer main body 11 rises and exceeds a predetermined value due to an internal accident such as an interlayer short circuit of the oil-filled transformer, the force that the valve member 18 receives from the oil in the transformer main body 11 exceeds the force of the coil spring 20. As a result, the valve member 18 moves upward and separates from the valve seat portion 16 to be in the state shown in FIG. Then, oil is ejected from the gap between the valve seat portion 16 and the valve member 18 as shown by an arrow A, thereby alleviating a rise in pressure in the transformer main body 11.

When another electrical protection device, for example, a ratio differential relay is operated to disconnect the oil-immersed transformer from the electric circuit, the pressure in the transformer main body 11 is reduced and the oil squirt is stopped. The valve member 18 returns to the original position by the restoring force of the above, and seals the valve seat portion 16. That is, when the accident is settled, the operation automatically returns to prevent the extra oil from flowing out of the conservator 12 having a high liquid level.

[0008] Since the conventional automatic return type pressure relief device 13 is configured as described above, when the pressure in the tank of the oil-filled transformer returns to the original state, the oil from the pressure relief device 13 is released. Is stopped to prevent extra oil from flowing out of the conservator 12. Therefore, it is not necessary to provide a pressure relief tube extending to a position higher than the conservator 12, unlike a pressure relief device of a pressure relief plate destruction type.

[0009]

However, if the pressure of the oil in the transformer body 11 rises sharply, the valve member 18
, A large rising force is applied, and the valve member 18 is rapidly opened. Also, when the pressure of the transformer main body 11 returns to the original state and the valve member 18 returns, the valve member 18 moves at a high speed and collides with the valve seat portion 16, and the outflow of oil is stopped suddenly. For this reason, a large impact occurs due to the water hammer phenomenon caused by the collision of the valve member 18 with the valve seat portion 16 and the outflow of oil being suddenly stopped.

For this reason, it is necessary to take measures against impact during operation, and the pressure relief device must be made strong and large. Accordingly, the weight and price increase. In addition, an increase in the weight of the pressure relief device may require measures against earthquakes. In particular, in the case of large-sized oil-filled electrical equipment, a large-diameter electrical equipment is required, and the above-mentioned increase in weight and measures against earthquakes become problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide an automatic reset type pressure-reducing device for an oil-filled electric device capable of suppressing an increase in weight even if the impact during operation is small and large. And

[0012]

In order to achieve the above object, in the automatic reset type pressure relief device according to the present invention, a storage chamber provided in communication with a tank of oil-filled electric equipment and in which oil flows in from the tank is provided. Having a casing, a valve member housed in the housing chamber and arranged opposite to the valve seat, a fixed member fixed to the casing, and capable of expanding and contracting in the opposite direction and having one end fixed to the fixed member and the other end fixed to the fixed member. A telescopic member fixed to the valve member to form an oil-tight telescopic chamber with the fixing member and the valve member; a return device for extending the telescopic member in the opposite direction; A valve device having a throttle communication hole that communicates in a state of being throttled to have
When the pressure in the storage chamber exceeds a predetermined value, the expansion chamber is opened to open to the atmospheric pressure and the oil flows out, and when the pressure in the storage chamber falls below the predetermined value, the expansion chamber is closed and the oil flows out of the expansion chamber. A trigger device for stopping, wherein when the trigger device releases the telescopic chamber to atmospheric pressure, the differential pressure between the housing chamber and the telescopic chamber causes the valve member to overcome the force of the return device and to be separated from the valve seat to open the chamber. The trigger device is closed, the trigger device closes, the outflow of oil from the telescopic chamber stops, and the return device expands the telescopic member while sucking oil from the storage chamber into the telescopic chamber through the throttle communication hole. Is brought into contact with the valve seat to stop the release of oil from the storage chamber. When the trigger device operates to open the telescopic chamber to the atmospheric pressure, the pressure in the storage chamber becomes higher, so that the valve member receives a force to overcome the force of the return device and try to reduce the telescopic chamber. The member separates from the valve seat. At this time, by adjusting the flow rate of the oil flowing out of the expansion / contraction chamber, it is possible to eliminate the possibility that the speed of the valve member becomes excessive and a large impact is generated. When the trigger device closes and the oil stops flowing out of the telescopic chamber, the return device extends the telescopic member while sucking oil from the storage chamber into the telescopic chamber through the throttle communication hole, and moves the valve member to the valve seat. And close the valve device. Adjusts the flow rate of oil that flows into the telescopic chamber through the throttle communication hole to control the speed at which the telescopic chamber expands and recovers, causing a water hammer phenomenon due to sudden closure and impact due to collision of the valve member with the valve seat. Suppress.

The elastic member is a bellows formed in a cylindrical shape and elastically deformable in the axial direction so as to be able to expand and contract, and the return device utilizes at least the restoring force due to the elastic deformation of the bellows. It is characterized by the following.
As described above, if the restoring force due to the elastic deformation of the bellows is used, the configuration of the return device is simplified without the need for a return spring or the like.

Further, the throttle communication hole has a flow rate adjusting device for adjusting the flow rate of oil passing therethrough. If the flow rate of the oil is adjusted by the flow rate adjusting device, the extension / return speed of the expansion / contraction chamber, that is, the closing speed by the valve member can be adjusted, and the impact due to the water hammer phenomenon and the collision of the valve member with the valve seat can be appropriately suppressed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 It is effective to adjust the moving speed of the valve member as a means for reducing the impact during the opening / closing operation of the automatic reset type pressure relief device. Hereinafter, specific means will be described. 1 to 4 show an embodiment of the present invention. 1A and 1B show the configuration of an automatic return type pressure relief device, in which FIG. 1A is an overall configuration diagram, FIG. 1B is a detailed view of a portion B in FIG. 1A, and FIG. FIG. 3 is a plan view, FIG. 3 is an operation explanatory view for explaining the operation, and FIG. 4 is an attached state diagram showing a state attached to the transformer main body.

As shown in FIG. 4, a cylindrical mounting flange portion 11 a is provided on the upper side of the transformer main body 11 so as to protrude rightward in the horizontal direction. A pressure relief device 31 of the shape is attached. The closing valve 30 prevents the oil from flowing out of the transformer main body 11 when the pressure releasing device 31 described below is attached or detached. The pressure relief device 31 includes an on-off valve 32, a throttle valve 34, and a trigger device 35 as shown in FIG.
The opening / closing valve 32 has a main oil drain pipe 36 and a trigger device 35.
Is connected to an auxiliary oil drain pipe 37 so that oil discharged when the pressure relief device 31 operates is not scattered.

The on-off valve 32 is configured as follows. The casing 321 is attached in communication with the shutoff valve 30, and has a box shape as shown in the plan view of FIG. On the lower surface of the casing 321, a cylindrical discharge cylinder 322 is oil-tightly welded by projecting an annular valve seat 323 integrally provided at a distal end thereof into the casing 321.

An annular bellows mounting seat 325 is welded to the lower side of the top plate of the casing 321. As shown in detail in FIG. 1B, the bellows mounting seat 325 is provided with one through hole 325a in the radial direction thereof, and has a cross-sectional area of the flow passage so as to have a predetermined flow resistance against oil. The nozzle 326 for adjusting the flow rate in the form of a thick-walled pipe, which has been selected, is tightly fitted. The nozzle 326 is bell-mouthed to stabilize the oil flow.

One end of a cylindrical bellows 327 made of a steel plate is oil-tightly welded to the bellows mounting seat 325. Also, a disc-shaped valve member 328 is welded to the other end of the bellows 327, and the top plate of the casing 321 also serving as a fixing member, the bellows mounting seat 325, the bellows 327, and the valve member 328 are made oil-tight. The expansion / contraction chamber 329 is formed. The bellows 327 is attached in a slightly compressed state, and the valve member 328 is pressed against the valve seat 323 by the elastic force to be restored to seal the oil so that oil does not leak.

A guide pipe 330 is welded to a top plate of the casing 321 which is a fixed side in the expansion / contraction chamber 329, and a guide cylinder 331 is welded to the valve member 328 so as to be fitted and slid. It guides when the valve member 328 moves up and down. The top plate of the casing 321, the bellows mounting seat 325, and the bellows 327 constitute a valve member operating device 324. In addition, the nozzle 32
6, an oil flow suppression plate 332 is provided on the side of the stop valve 30 so that oil does not flow directly from the stop valve 30 to the nozzle 326.

A pressure-compensating throttle valve 34 for adjusting the flow rate of oil in communication with the expansion / contraction chamber 329 and a trigger valve 352 of a trigger device 35 for opening and closing the flow path are connected in series. The trigger device 35 detects the oil pressure in the casing 321 by a semiconductor strain gauge type pressure detector 351 attached to the casing 321, and sends a signal when the pressure exceeds a predetermined value to open the trigger valve 352.

The surface area on the lower surface side of the valve member 328 is S
1, the area of a portion surrounded by the valve seat 323 and at the atmospheric pressure is S2, the area of the valve member 328 inside the telescopic chamber 329 is S3, the restoring force when the bellows 327 is compressed is f1, and the valve member is f1. The weight of the oil inside the casing 321 is set to P2 (strictly speaking, the weight of the guide cylinder 331 and the like is added in addition to the weight f2, but these are omitted).
1. When the telescopic chamber 329 is opened to the atmospheric pressure, the valve member 32
The force F that tries to move 8 upward is represented by the following equation (1). F = (S1-S2) P1-f1-f2 (1)

Accordingly, when the pressure in the casing 321 increases and the trigger device 35 operates to open the telescopic chamber 329 to the atmospheric pressure, the force (S1-S2) P1 due to the pressure in the casing 321 at that time is increased. F, which exceeds the sum of the restoring force f1 of the bellows 327 and the own weight f2 of the valve member 328, moves the valve member 328 upward.

The pressure relief device 31 configured as described above
The on-off valve 32 and the trigger valve 352 are always closed, communicate with the transformer main body 11 through the opened closing valve 30, and the insulating oil flows from the transformer main body 11 into the casing 321 to fill the casing 321. (See FIG. 4). The drain cylinder 322, the main oil drain pipe 36, and the sub oil drain pipe 37 are open to the atmosphere.

Next, the operation will be described. When the pressure of the oil in the transformer main body 11 rises and exceeds a predetermined value due to a coil short-circuit or the like, the pressure detector 351 issues a signal to open the trigger valve 352. Since the expansion and contraction chamber 329 is opened to the atmospheric pressure and becomes lower than the pressure P1 in the casing 321, the force received by the valve member 328 due to the pressure in the casing 321 increases as in the above equation (1), and the elastic force of the bellows 327. And bellows 3 overcoming the weight of valve member 328
27 moves upward while compressing the oil, and the oil is discharged from the auxiliary oil drain pipe 37 with the movement. Note that the bellows 327 and the valve member 328 are a return device in the present invention.

At this time, the moving speed of the valve member 328, that is, the opening speed of the on-off valve 32, is determined by the discharging speed of the oil discharged through the auxiliary oil discharging pipe 37. The oil flow rate is adjusted by a pressure-compensated throttle valve 34. At this time, the oil in the casing 321 flows into the telescopic chamber 329 while being throttled by the nozzle 326.
The pressure difference from the pressure 29 is almost equal to P1. Since the flow rate of the oil flowing into the expansion / contraction chamber 329 is smaller than the flow rate of the oil discharged through the throttle valve 34, the opening / closing speed of the valve member 328 is mainly determined by adjusting the throttle of the throttle valve 34. Is done. Then, as the valve member 328 is separated from the valve seat 323, oil flows out to the discharge cylinder 322 as indicated by an arrow C in FIG.

When the ratio differential relay or the like operates and the internal accident of the transformer body 11 subsides, the cause of the increase in the oil pressure disappears, and the pressure in the casing 321 returns to the original state. The pressure detector 351 detects that the pressure in the casing 321 has fallen below a predetermined value, and closes the trigger valve 352. Then, the pressure in the expansion / contraction chamber 329 is reduced to the casing 32.
Since the pressure becomes equal to 1, the valve member 328 moves downward due to the restoring force of the bellows 327 and the weight of the valve member 328.

At this time, the moving speed of the valve member 328 is determined by the speed of sucking oil from the nozzle 326 into the telescopic chamber 329. Therefore, the closing speed of the on-off valve 32 can be adjusted according to the degree of restriction by the nozzle 326. In this embodiment, the nozzles 326 having different flow path cross-sectional areas may be used if necessary.
I choose to use.

That is, it is possible to easily adjust and control the opening speed of the on-off valve 32 mainly by the throttle valve 34 and the closing speed by the nozzle 326. Further, the occurrence of a water hammer phenomenon due to abrupt opening and closing and an impact due to a collision between the valve member and the valve seat are prevented. Such a soft operation makes the oil-immersed transformer large, for example, the discharge cylinder 3
Even when a large-diameter on-off valve 32 having a diameter of 300 mm or more is required, the mechanical strength does not need to be so large, and an increase in weight can be suppressed.

Embodiment 2 FIG. The present invention is not limited to the configuration described above, and various modifications are possible without impairing the object of the present invention. For example, in the above embodiment, the telescopic chamber 329 includes the casing 321 and the valve member 3.
5 and a bellows 327, but as shown in the configuration diagram of FIG. 5, a disc-shaped plate member 63 is provided separately in place of the valve member 328, and a disc-shaped valve member 628 is attached to the plate member 63. The pressure relief device 61 may be configured at 62. If the valve member 628 is separately provided in this manner, the valve member 628 can be made smaller, and the processing of the contact surface with the valve seat 323 becomes easier.

Incidentally, the valve member may be rotated so as to abut on the valve seat. Further, the bellows 327 may be made of rubber or synthetic resin, and the flow rate adjusting device such as the nozzle 326 and the throttle valve 34 may be of another type. Further, a pilot valve that opens and closes using the pressure in the casing 321 as a pilot pressure can be used as the trigger device.

Further, as shown in the mounting state diagram of FIG. 6, the pressure relief device 3 is located at a lower position below the transformer main body 11.
It is also possible to mount the pressure-releasing device 31 at such a low position, so that the pressure relief device 31 can be easily inspected and maintained. When the pressure relief device 31 is removed, the closing valve 30 is closed to prevent the oil from flowing out. In addition, it can be used not only for an oil-filled transformer but also for an oil-filled reactor, a condenser, and other oil-filled electrical equipment.

[0033]

Since the present invention is configured as described above, the following effects can be obtained. That is, the automatic return type pressure relief device of the present invention is provided in communication with the tank of the oil-filled electric equipment and has a casing having a storage chamber into which oil flows from the tank, and is disposed in the storage chamber and opposed to the valve seat. A valve member, a fixed member fixed to the casing, and an expandable and contractible one-way, one end is fixed to the fixed member, and the other end is fixed to the valve member. A telescopic member that forms the telescopic chamber, a return device that extends the telescopic member in the opposite direction, and a throttle communication hole that communicates with the telescopic chamber and the storage chamber squeezed so as to have a predetermined flow path resistance. The valve device has a valve device, which opens when the pressure in the storage chamber exceeds a predetermined value, opens the telescopic chamber to atmospheric pressure and allows oil to flow out, and closes when the pressure in the storage chamber becomes equal to or lower than the predetermined value and closes the telescopic chamber. Trigger device to stop oil spill,
When the trigger device releases the telescopic chamber to atmospheric pressure, the differential pressure between the storage chamber and the telescopic chamber causes the valve member to overcome the force of the return device and separate from the valve seat to release oil from the storage chamber. The trigger device closes to stop the oil from flowing out of the telescopic chamber, and the return device extends the telescopic member while sucking oil from the storage chamber into the telescopic chamber through the throttle communication hole, thereby causing the valve member to contact the valve seat. Since the release of oil from the storage chamber is stopped by contact, the pressure of the storage chamber becomes higher when the trigger device operates to open the telescopic chamber to atmospheric pressure,
A force acting on the valve member to reduce the expansion chamber overcoming the force of the return device acts, and the valve member is separated from the valve seat. At this time, by adjusting the flow rate of the oil flowing out of the expansion / contraction chamber, it is possible to eliminate the possibility that the speed of the valve member becomes excessive and a large impact is generated. When the trigger device closes and the oil stops flowing out of the telescopic chamber, the return device extends the telescopic member while sucking oil from the storage chamber into the telescopic chamber through the throttle communication hole, and moves the valve member to the valve seat. And close the valve device.
The flow rate of oil flowing into the telescopic chamber through the throttle communication hole is adjusted to control the speed at which the telescopic chamber expands and returns, and water hammer due to sudden closing and impact due to collision of the valve member with the valve seat. Suppress. Therefore, the mechanical strength does not need to be so large, the increase in weight can be suppressed, and the earthquake resistance can be improved.

The expansion and contraction member is a bellows formed in a cylindrical shape and elastically deformable in the axial direction so as to be able to expand and contract, and the return device utilizes at least the restoring force due to the elastic deformation of the bellows. Since the present invention is characterized in that a restoring spring or the like can be omitted by using the restoring force due to the elastic deformation of the bellows, the structure of the restoring device is simplified.

Further, since the throttle communication hole has a flow rate adjusting device for adjusting the flow rate of the oil passing therethrough, the flow rate of the oil is adjusted by the flow rate adjusting device, whereby the expansion and contraction of the telescopic chamber can be extended. The return speed, that is, the closing speed by the valve member can be adjusted, and the impact due to the water hammer phenomenon and the collision of the valve member with the valve seat can be more appropriately suppressed.

[Brief description of the drawings]

1A and 1B show an automatic return type pressure relief device according to an embodiment of the present invention. FIG. 1A is an overall configuration diagram, and FIG. 1B is a detailed view of a portion B in FIG. is there.

FIG. 2 is a plan view of the on-off valve portion of FIG.

FIG. 3 is an operation explanatory diagram illustrating an operation of the pressure relief device of FIG. 1;

FIG. 4 is a mounting state diagram of the pressure relief device of FIG. 1;

FIG. 5 is a configuration diagram of an automatic return type pressure release device showing another embodiment of the present invention.

FIG. 6 is an attachment state diagram showing another attachment example.

FIG. 7 is a mounting state diagram showing a mounting state of a conventional automatic return type pressure release device.

FIG. 8 is a configuration diagram of a conventional pressure relief device.

FIG. 9 is an explanatory diagram for explaining an operation of a conventional pressure relief device.

[Explanation of symbols]

11 transformer body, 31 pressure relief device, 32 on-off valve, 3
Reference Signs List 21 casing, 323 valve seat, 324 valve member operating device, 325a through hole, 326 nozzle, 327 bellows, 328 valve member, 34 throttle device, 35 trigger device, 351 pressure detector, 352 trigger valve, 61
Pressure relief device, 62 on-off valve, 64 plate material, 628 valve member.

Claims (3)

[Claims] 1. A casing provided in communication with a tank of an oil-filled electric machine and having a storage chamber into which oil flows from the tank, a valve member stored in the storage chamber and opposed to a valve seat, and the casing. A fixed member fixed to the first member and one end fixed to the fixed member, and the other end fixed to the valve member. A telescopic member that forms a telescopic chamber, a return device that extends the telescopic member in the opposite direction, and a throttle communication hole that communicates the telescopic chamber and the housing chamber in a state where they are squeezed so as to have a predetermined flow path resistance. And a valve device having a portion, and when the pressure in the storage chamber exceeds a predetermined value, the valve apparatus is opened to open the telescopic chamber to the atmospheric pressure to allow oil to flow out, and the pressure in the storage chamber becomes equal to or lower than the predetermined value. When closed above the telescopic room A trigger device for stopping the outflow of the oil, and when the trigger device releases the telescopic chamber to atmospheric pressure, the differential pressure between the housing chamber and the telescopic chamber causes the valve member to force the return device. The oil is released from the valve seat to release the oil from the storage chamber, the trigger device is closed to stop the oil from flowing out of the expansion and contraction chamber, and the return device is used to release the oil through the throttle communication hole. An automatic return type pressure relief device that extends the expandable member while sucking oil from the storage chamber into the expansion and contraction chamber and causes the valve member to abut against the valve seat to stop releasing oil from the storage chamber. 2. The expansion / contraction member is a bellows formed in a cylindrical shape and elastically deformable in the axial direction so as to be able to expand and contract, and the return device utilizes at least a restoring force due to the elastic deformation of the bellows. 2. The automatic return type pressure relief device according to claim 1, wherein 3. The automatic return type pressure relief device according to claim 1, wherein the throttle communication hole has a flow rate adjusting device for adjusting a flow rate of oil passing therethrough.