JP4328162B2 - Pressure relief device for electrical equipment - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a pressure relief device for electrical equipment used to release the pressure when the pressure in a tank of electrical equipment such as an oil-filled transformer and a gas-insulated transformer rises excessively.

  In electrical equipment such as oil-filled transformers and gas-insulated transformers, when a short circuit accident or the like occurs in the tank, an abnormal pressure rise occurs in the tank due to a rapid temperature rise. If the pressure rise is left unattended, the tank may be destroyed, so a pressure relief device is connected to the tank and the pressure relief device is released when the pressure in the tank exceeds the limit value. By performing the operation, the pressure in the tank is released.

  This type of pressure relief device has a pressure relief hole on the rear end side as shown in Patent Document 1, for example, and the rear end portion is directly or via a connecting pipe in a tank of an electric device. A pressure release cylinder to be connected, a valve plate provided so as to open and close the pressure release hole from the inside of the pressure release cylinder, and urged toward the side where the pressure release hole is opened by the internal pressure when the internal pressure of the tank rises, A movable shaft coupled to the valve plate and displaced in the axial direction of the pressure release cylinder in accordance with the displacement of the valve plate; and a pressure release spring that biases the valve plate toward the side closing the pressure release hole. When the internal pressure exceeds the limit value, the valve plate is displaced toward the side where the pressure release hole is opened against the urging force of the pressure release spring so as to perform the pressure release operation.

  In addition, the conventional pressure relief device includes a pressure relief membrane attached so as to close the tip of the pressure relief cylinder, and a movable shaft that is displaced toward the tip of the pressure relief cylinder together with the valve plate during the pressure relief operation. When the sharp tip hits the pressure release membrane, the pressure release membrane was destroyed.

  Furthermore, this type of pressure relief device includes a microswitch in the pressure relief cylinder, and a switch drive mechanism that drives the microswitch during the pressure relief operation to turn it on. When the microswitch is turned on, The pressure release operation detection signal indicating that the pressure release operation has been performed is obtained.

  In an electrical device equipped with this type of pressure relief device, when the pressure in the tank rises, the pressure in the tank opens the pressure relief hole in the pressure relief cylinder against the biasing force of the pressure relief spring. The tip of the movable shaft, which is displaced with the valve plate at the same time, breaks the pressure relief membrane and opens the tip of the pressure relief cylinder, so that the pressure in the tank is released through the pressure relief cylinder. .

  At this time, since the microswitch is turned on, a pressure release operation detection signal indicating that the pressure release operation has been performed by the on operation of the microswitch can be obtained. The pressure release operation detection signal obtained from the microswitch is used for generating an alarm or tripping a circuit breaker.

  The valve plate is returned to the position where the pressure release hole is closed by the urging force of the pressure release spring when the pressure in the tank drops below the limit value due to the pressure release operation. With this returning operation, the driving of the microswitch is released, so that the microswitch returns to the off state and stops outputting the pressure release operation detection signal.

Thus, in the conventional pressure relief device, the microswitch stops outputting the detection signal when the pressure relief operation is finished and the valve plate returns to the position where the pressure relief hole is closed. Since the pressure film is destroyed, it is possible to leave a trace that the pressure release operation has been performed by the destruction of the pressure release film.
Japanese Utility Model Publication No. 49-71722

  In the conventional pressure release device, the pressure release operation detection signal generated by the microswitch disappears when the pressure release operation is completed and the valve plate returns to the position where the pressure release hole is closed. In order to leave a trace of what was done, it was necessary to provide a pressure relief membrane that was destroyed during the pressure relief operation. Further, in the conventional pressure relief device, since a micro switch having no waterproof property is used as a switch for obtaining a pressure relief operation detection signal, a mechanism for sealing the pressure relief membrane attachment portion is provided, and the inside of the pressure relief cylinder is provided. It was necessary to shield from the outside. For this reason, the structure of the pressure relief device becomes complicated and the price of the device cannot be avoided.

  Also, in the conventional pressure relief device, the switch that obtains the pressure relief operation detection signal was not waterproof, so the contact part deteriorated when moisture entered the pressure relief cylinder due to the deterioration of the seal part of the pressure relief membrane. However, the detection operation may not be performed.

  An object of the present invention is to maintain a state in which a pressure release operation detection signal is generated even after the pressure release operation is completed and the valve plate returns to the position where the pressure release hole is closed. Thus, an object of the present invention is to provide a pressure relief device for an electrical apparatus that can reduce the cost by omitting the pressure relief membrane.

  Another object of the present invention is for an electrical apparatus that uses a pressure relief operation detection switch having a waterproof structure as a switch for detecting a pressure relief operation so that the switch is not deteriorated due to moisture and has improved reliability. The object is to provide a pressure relief device.

  The present invention provides a pressure relief cylinder having a pressure relief hole on the rear end side, the rear end part being connected to a tank of an electrical device directly or via a connecting pipe, and a pressure relief from the inside of the pressure relief cylinder. A valve plate which is provided to open and close the hole and is urged toward the side where the pressure release hole is opened by the internal pressure when the internal pressure of the tank rises, and a pressure release cylinder connected to the valve plate and displaced with the valve plate A movable shaft that can be displaced in the axial direction and a pressure release spring that urges the valve plate toward the side that closes the pressure release hole. When the pressure in the tank exceeds the limit value, the valve plate is attached to the pressure release spring. The present invention relates to a pressure relief device for electrical equipment that performs a pressure relief operation by displacing the pressure relief hole to a side that opens against a force.

  In the present invention, the contact portion enclosed in the case and the operation portion which is provided so as to be able to be displaced between the non-detection position and the detection position and causes the contact portion to perform a detection operation when the detection position is reached. A pressure release operation detection switch having a waterproof structure attached to the pressure release cylinder with at least the operating portion positioned in the pressure release cylinder, and between the first position and the second position in the pressure release cylinder Is rotated so as to operate the operation part of the pressure release operation detection switch, and when the first position is reached, the operation part of the pressure release operation detection switch reaches the detection position. An operation lever provided to return the operation unit to the non-detection position in the process of rotating from the first position to the second position, and a lever urging for urging the operation lever to rotate to the first position When the spring and valve plate are in the state before releasing the pressure, Combined and provided operating lever holding piece attached to the movable shaft in order to retain the second position against the operating lever to the urging force of the lever biasing spring.

  The operation lever, lever urging spring, and operation lever holding piece constitute a limit switch operation mechanism that operates the pressure release operation detection switch.

  The operation lever holding piece can engage with the operation lever in the second position when the valve plate is in the position to close the pressure release hole, but can engage with the operation lever in the first position. It is provided so that it is engaged with the operating lever when it is in a state before the pressure release operation is performed, and it is movable when the valve plate is displaced to the side that opens the pressure release hole and performs the pressure release operation. The operation lever holding piece is configured to be detached from the operation lever as the shaft is displaced.

  With the above configuration, when the pressure release operation is performed, the operation lever holding piece is detached from the operation lever for operating the pressure release operation detection switch, and the operation lever is rotated to the first position side to release the operation lever. The pressure operation detection switch performs the detection operation. Thereby, the pressure release operation detection signal can be obtained from the pressure release operation detection switch. Once the pressure release operation is performed and the operation lever reaches the first position, the operation lever holding piece cannot be engaged with the operation lever. Therefore, the pressure release operation detection switch remains in the detection position. The pressure release operation detection signal is continuously generated even after the valve plate returns to the position where the pressure release hole is closed.

  Thus, in the present invention, even after the pressure release operation is completed and the valve plate is restored, the operation portion of the pressure release operation detection switch is held at the detection position, and the pressure release operation detection switch detects the pressure release operation detection signal. Therefore, it is possible to leave a trace that the pressure release operation has been performed without providing a pressure release film that is destroyed during the pressure release operation. Therefore, the pressure release membrane can be omitted, and the structure can be simplified and the cost can be reduced.

  In the present invention, since the pressure release operation detection switch having a waterproof structure is used as a switch for detecting the pressure release operation, it is possible to prevent a problem that the switch deteriorates due to moisture and a detection signal cannot be obtained. , Can increase the reliability. As the pressure release operation detection switch, for example, a limit switch having a waterproof structure can be used. In general, limit switches are configured to withstand use in a variety of environments, so waterproof limit switches are readily available.

  In a preferred aspect of the present invention, the detection switch container is attached to the outside of the peripheral wall portion of the pressure release cylinder, and the pressure release operation detection switch is attached in a state where the case is accommodated in the detection switch container. In this case, the operation portion of the pressure release operation detection switch is introduced into the pressure release cylinder through a through hole formed in the peripheral wall portion of the pressure release cylinder.

  In the case of such a configuration, it is not necessary to provide a space for accommodating the pressure release operation detection switch in the pressure release cylinder. Therefore, the diameter of the pressure release cylinder can be reduced to reduce the size of the pressure release device. .

  In a preferred embodiment of the present invention, the distal end side of the pressure release cylinder is opened to the atmosphere without being closed by a pressure release membrane or the like.

  With this configuration, since the pressure release film is not provided, it is possible to reduce costs by reducing the number of components and the structure.

In a preferred aspect of the present invention, the pressure release cylinder is arranged with its tip end side facing downward, and a vent pipe that communicates the inside of the pressure release cylinder with the outside air is connected to the upper part of the pressure release cylinder. An insect screen for preventing insects from entering and forming a nest in the ventilation pipe is attached to the opening of the ventilation pipe.

As described above, when the vent pipe is attached, the air flows into the pressure relief cylinder from the opening at the lower end in the pressure relief cylinder and rises in the pressure relief cylinder and then flows out from the vent pipe to the outside. Since it can be generated, the inside of the pressure release cylinder can be dried to prevent dew condensation in the pressure release cylinder.

  In order to prevent deterioration of the operation mechanism that operates the pressure release operation detection switch, it is preferable that the operation lever, the lever urging spring, and the operation lever holding piece are made of a rust-proof material such as stainless steel.

  As described above, according to the present invention, when the pressure release operation is performed, the operation lever holding piece is removed from the operation lever that operates the pressure release operation detection switch for detecting the pressure release operation. After the detection operation is performed by the operation detection switch and the pressure release operation is performed once, the operation lever holding piece does not engage the operation lever even if the valve plate returns to the position to close the pressure release hole. Thus, since the pressure release operation detection switch is held in the state during the detection operation, the pressure release operation detection signal can be obtained from the pressure release operation detection switch even after the pressure release operation is completed. Therefore, it is possible to leave a trace of the pressure release operation without providing a pressure release film that is destroyed during the pressure release operation, simplifying the structure by omitting the pressure release film, and reducing the cost. Can be planned.

  Further, according to the present invention, since the pressure release operation detection switch having a waterproof structure is used as a switch for detecting the pressure release operation, there arises a problem that the switch deteriorates due to moisture and a detection signal cannot be obtained. It can prevent and increase reliability.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 1 and 2 show the configuration of an embodiment of the present invention. FIG. 1 is a cross-sectional view showing the overall configuration of the pressure release device according to the embodiment. FIG. 2 shows a pressure release operation detection switch. It is sectional drawing of the principal part which shows the state which detected the pressure release operation | movement.

  In FIG. 1, reference numeral 1 denotes a pressure relief cylinder which is formed in a cylindrical shape and has a pressure relief hole 2 on the rear end side. The illustrated pressure release cylinder 1 includes a pressure release cylinder main body 101 formed in a cylindrical shape by a metal such as iron, a flange plate 102 welded to a rear end portion of the pressure release cylinder main body 101, and a pressure release cylinder main body 101. It consists of a flange portion 103 attached by welding to a portion near the tip portion, and a circular shape that is smaller than the inner diameter of the pressure release cylinder body 101 and shares the central axis with the pressure release cylinder body 101 at the center of the flange plate 102. The pressure release hole 2 is formed. An annular valve packing 3 is attached around the opening of the pressure release hole 2 on the pressure release cylinder 1 side.

  The pressure release cylinder 1 has an upper end connected to a flange plate 102 on the rear end (upper end in the illustrated example) side of a tank (not shown) of an electric device such as an oil-filled transformer or a gas-insulated transformer. By fastening to the flange 301 at the lower end of the connection pipe 4 with fastening means comprising a bolt 5 and a nut 6, the connection pipe 4 is connected to the tank of the electrical equipment. The flange portion 103 provided near the distal end portion (lower end in the illustrated example) of the pressure release cylinder 1 is an insulating oil or oil discharged from the electrical equipment tank through the connection pipe 4 and the pressure release cylinder 1 during the pressure release operation. This is used to connect the oil guide pipe to the pressure release cylinder 1 when an oil guide pipe for guiding the gas to a predetermined disposal place is provided.

  A plurality of support members 104 are welded at intervals in the circumferential direction of the pressure release cylinder main body on the inner peripheral side of the portion to which the flange portion 103 of the pressure release cylinder main body 101 is attached, and these support members 104, 104, A disc-shaped first movable shaft support plate 7 is attached to each other with screws 8. The first movable shaft support plate 7 is made of a metal disk having an outer diameter smaller than the inner diameter of the pressure release cylinder main body 101, and the outer peripheral portion of the first movable shaft support plate 7 and the pressure release cylinder. Through the gap g between the inner periphery of the main body 101, the tip end portion (lower end in the illustrated example) of the pressure release cylinder 1 is opened to the outside air.

  A through-hole 107 is formed through the peripheral wall portion near the rear end of the pressure-release cylinder main body 101, and a vent pipe 108 is connected to an opening to the outside of the through-hole 107. The illustrated vent pipe 108 is made of an L-shaped metal pipe, one end of which is aligned with the through hole 107 and abuts the periphery of the opening of the through hole 107, and the other end is released. It arrange | positions in the state which faced the front-end | tip part side (lower side in the example of illustration) of the cylinder 1, and is connected to the peripheral part of the through-hole 107 by welding. An insect screen 109 is attached to the opening on the other end of the vent pipe 108 to prevent insects from entering the vent pipe and forming a nest. Since the air pipe 108 is made of a relatively thin pipe, if insects enter the air pipe 108 to form a nest, the air flow path inside the air pipe may be blocked. If this is done, the risk of such a situation occurring can be eliminated.

  A second movable shaft support plate 11 is disposed on a flange plate 102 on the rear end side of the pressure release cylinder 1 via a spacer 10. The movable shaft support plate 11 is made of a disc having an outer diameter smaller than the inner diameter of the connection pipe 4, and penetrates the support plate 11 and the spacer 10 and is bolted into the flange plate 102. Thus, the support plate 11 is fastened to the flange plate 102.

  A hole 7a is provided at the center of the first movable shaft support plate 7, and a bearing bush 13 is attached to the hole. A hole 11a sharing the central axis with the bush 13 and the pressure relief cylinder 1 is formed at the center of the second movable shaft support plate 11, and the hole 11a is formed on the surface of the support plate 11 opposite to the pressure relief cylinder 1. An annular spring receiving plate 14 having a hole with the same diameter as the center is welded in a state aligned with the hole 11a. A movable shaft 15 is provided by slidably penetrating the hole 11a of the second movable shaft support plate 11 and the hole at the center of the spring receiving plate 14. A small diameter portion 15a having a smaller outer diameter than the other portions is formed in a portion near the tip of the movable shaft 15, and the small diameter portion 15a is slidably fitted to the bush 13. The length of the small diameter portion 15a is set slightly longer than the stroke of the valve plate described later. A step portion 15b is formed between the small-diameter portion 15a of the movable shaft 15 and another portion, and the step portion 15b abuts against the bush 13 so that the movable shaft 15 is moved toward the distal end portion of the pressure release cylinder 1. The displacement is regulated.

  A valve plate 16 is fixed to a portion located in the pressure release cylinder 1 near the rear end of the movable shaft 15. The valve plate 16 is made of a disk having a diameter larger than that of the pressure release hole 2, and abuts against the annular valve packing 3 attached to the periphery of the pressure release hole 2 as shown by a solid line in the figure. Displacement between the closed position where the pressure hole 2 is closed and the open position where the pressure release hole 2 is opened away from the valve packing 3 as shown by the chain line in the figure. The hole 2 is opened and closed from the inside of the pressure release cylinder 1.

  One end of a guide rod 17 extending in parallel with the movable shaft 15 is attached at a position off the center of the valve plate 16, and this guide rod 17 is a guide hole provided through the second movable shaft support plate 11. 11c is slidably fitted. The guide plate 17 and the guide hole 11c are fitted to prevent the valve plate 16 and the movable shaft 15 from rotating. Therefore, the valve plate 16 and the movable shaft 15 are displaced only in the axial direction of the pressure release cylinder 1.

  A pressure in a tank of an electric device (not shown) is applied to the valve plate 16 through the connection pipe 4, and the valve plate 16 is urged to open the pressure release hole 2 by the application of this pressure. A pressure release spring 18 that urges the valve plate 16 toward the closing side of the pressure release hole 2 is fitted to the rear end portion of the movable shaft 15 protruding from the second movable shaft support plate 11. The pressure release spring is composed of a compression spring, and one end thereof is in contact with a spring receiving plate 14 welded to the second movable shaft support plate 11. An annular spring retainer plate 19 is fitted to a portion protruding from the pressure release spring 18 at the rear end portion of the movable shaft 15, and a nut screwed into a male screw portion 15 c formed at the rear end portion of the movable shaft 15. 20 and 21 are in contact with the spring retainer plate 19. By adjusting the position of the spring pressing plate 19 by the nuts 20 and 21, the urging force of the pressure release spring 18 is adjusted. The biasing force applied to the valve plate 16 from the pressure release spring 18 is set to be approximately equal to the force applied to the valve plate 16 from the tank side of the electrical device when the pressure in the tank of the electrical device reaches the limit value. When the pressure in the tank of the electric device exceeds the limit value, the valve plate 16 is displaced toward the side that opens the pressure release hole 2 against the urging force of the pressure release spring 18.

  In the illustrated pressure relief device, when the valve plate 16 is in the closed position, the distal end of the small diameter portion 15a of the movable shaft 15 with the stepped portion 15b on the distal end side of the movable shaft 15 separated from the bush 13 by a predetermined distance. Of the small diameter portion 15a so that the stepped portion 15b contacts the bush 13 and restricts the displacement of the valve plate 16 when the valve plate 16 reaches the open position. Is set.

  The detection switch container 22 is attached to the outside of the peripheral wall portion of the portion near the rear end of the pressure release cylinder main body 101 by welding. A through-hole 110 that allows the inside of the container 22 and the inside of the pressure relief cylinder 1 to communicate with each other is formed in the peripheral wall near the rear end of the pressure relief cylinder body 101. An operation lever mounting plate 23 is disposed at a position corresponding to the container 22 inside the peripheral wall of the portion near the rear end of the pressure release cylinder main body 101, and the attachment plate 23 is connected to the pressure release cylinder main body by a plurality of screws 24. 101 is fixed to the peripheral wall portion. The operation lever mounting plate 23 is formed with a hole 23a that is aligned with the through hole 110, and a stopper 25 that extends toward the movable shaft 15 is fixed around the opening of the hole 23a.

  In the container 22, a pressure release operation detection switch 30 having waterproofness is accommodated. The pressure release operation detection switch 30 is a switch having a contact portion enclosed in a case 31 and a linear displacement type movable element 32 provided with an operation portion 32a made of a roller at the tip. The operation portion 32 a of the pressure release operation detection switch 30 can be displaced between the non-detection position and the detection position together with the movable element 32, and the movable element 32 is not moved by a return spring housed in the case 31. It is biased toward the detection position. In the illustrated pressure release operation detection switch, when the operating force is not applied to the operating portion 32a, the operating portion 32a and the mover 32 are in the non-detection position (position shown in FIG. 1), and the operating portion 32a is When an operation force is applied to push the case 31, the operation portion 32 a is linearly displaced toward the case 31 along the central axis of the mover 32 together with the mover 32 to reach the detection position. It has become. The contact part of the pressure release operation detection switch 30 is composed of a break contact and a make contact. When the operation part 32a is in the non-detection position, the break contact is in the on state, and when the operation part 32a reaches the detection position. The make contact is turned on to perform the detection operation.

  For example, it is appropriate to use a waterproof limit switch as the pressure release operation detection switch. The pressure release operation detection switch 30 has a through hole 110 in which the movable element 32 is provided in the peripheral wall portion of the pressure release cylinder, with the central axis (displacement direction) of the movable element 32 orthogonal to the central axis of the movable shaft 15. It is arranged in a state where the operation portion 32a is introduced into the pressure release cylinder 1 and positioned in the pressure release cylinder 1, and is fixed in the container 22 by appropriate means.

  The opening of the detection switch container 22 is closed by a cover plate 35 fastened to the flange of the opening of the container by a screw 34. One end of a wiring duct 36 for guiding a lead wire led out from the contact point of the pressure release operation detection switch 30 to an external circuit is connected to the lid plate 35 of the container 22.

  A support shaft 40 extending in a direction perpendicular to the axial direction of the movable element 32 of the pressure release operation detection switch is attached to the end of the operation lever mounting plate 23 located on the rear end side of the pressure release cylinder 1. By fitting an annular shaft holding portion 41 a formed at the rear end portion of the operation lever 41 to the support shaft 40, the operation lever 41 is rotatably supported by the mounting plate 23.

  The operation lever 41 is at least the first position shown in FIG. 2 in the pressure release cylinder 1 (the position where the operation lever 41 approaches the pressure release operation detection switch and comes into contact with the stopper 25), and the operation lever 41 shown in FIG. It is supported so as to rotate between a second position (a position at a predetermined distance from the stopper 25), and the operation portion 32a of the pressure release operation detection switch 30 is operated during the rotation process. Is. In the present embodiment, the operation lever 41 is moved from the second position shown in FIG. 1 toward the first position shown in FIG. When the operation portion 32a at the front end is pushed to displace the operation portion 32a toward the detection position and the operation lever 41 reaches the first position where it comes into contact with the stopper 25 as shown in FIG. The operation part 32a of the pressure operation detection switch 30 reaches the detection position. Further, when the operation lever 41 is rotated from the first position shown in FIG. 2 toward the second position shown in FIG. 1, the operation portion 32 a of the pressure release operation detection switch 30 is incorporated in the switch 30. The operating portion 32a is returned to the non-detection position until the operation lever 41 reaches the second position shown in FIG. Yes.

  In order to urge the operation lever 41 to rotate toward the first position, a lever urging spring 42 made of a tension spring is provided between the operation lever mounting plate 23 and the tip of the operation lever 41. Yes. At the tip of the operation lever 41, a ring-shaped member 41b for engaging an operation tool when the operation lever is displaced toward the second position against the biasing force of the lever biasing spring 42. Is attached.

  An operation lever holding piece 43 is attached to the movable shaft 15 in order to hold the operation lever 41 in the second position shown in FIG. The operating lever holding piece 43 is made of an L-shaped plate. When the valve plate 16 is in a state before the pressure release operation, the tip of the operating lever is engaged with the tip of the operating lever 41 and the operation is performed. The lever 41 is held at the second position against the biasing force of the lever biasing spring 42.

  In the illustrated example, one end of the operation lever holding piece 43 is fixed to the sleeve 44 slidably fitted to the movable shaft 15, and the position of the operation lever holding piece 43 is adjusted by adjusting the axial position of the sleeve 44. It can be adjusted as appropriate. A long hole 44a extending in the axial direction of the movable shaft 15 is formed in the sleeve 44, and screws 45, 45 fixed to the movable shaft 15 are loosely fitted in the long hole 44a. Nuts 46 and 46 are screwed onto the screws 45 and 45, respectively, and by tightening the nuts 46 and 46, the sleeve 44 can be fixed at an appropriate position.

  The position of the operating lever holding piece 43 is such that when the valve plate 16 is in a position to close the pressure release hole 2, the tip 43a can be engaged with the operating lever 41 in the second position. The lever is adjusted to a position where it cannot be engaged with the operation lever.

  In the illustrated pressure release device, a switch operating mechanism that operates the pressure release operation detection switch 30 by an operation lever mounting plate 23, an operation lever 41, an operation lever holding piece 43, a sleeve 44 and a lever biasing spring 42. Is configured. In order to prevent the operating mechanism from deteriorating due to moisture that has entered the pressure release cylinder 1, the operating lever 41, the operating lever holding piece 43, the sleeve 44, and the lever biasing spring 42 are made of rust-proof material such as stainless steel. It is formed with the metal which has. Further, the movable shaft 15, the valve plate 16 and the pressure release spring 18 are also formed of a material having rust prevention property or a material subjected to rust prevention treatment. Furthermore, the anti-rust treatment is also applied to the pressure release cylinder 1 and the like.

  In the above-described pressure relief device, prior to use, the tip 43a of the operation lever holding piece 43 is engaged with the tip of the control lever 41 as shown in FIG. In this state, when an accident occurs in the tank of the electric device and the pressure in the tank rises abnormally, the valve plate 16 is displaced toward the open position indicated by a chain line in FIG. At this time, the movable shaft 15 is displaced downward in the drawing together with the valve plate 16, and the operation lever holding piece 43 attached to the movable shaft 15 is also displaced downward, so that the operation lever holding piece 43 is disengaged from the operation lever 41 and the operation lever. 41 is rotated toward the pressure release operation detection switch 30 (toward the first position) by the biasing force of the lever biasing spring 42. As a result, the operation part 32a of the pressure release operation detection switch is caused to reach the detection position, and thus the pressure release operation detection switch performs a detection operation and generates a pressure release operation detection signal by closing the make contact.

  Thereafter, when the pressure in the tank of the electric device decreases, the valve plate 16 automatically returns to the closed position shown by the solid line in FIG. 1 by the urging force of the pressure release spring 18. 2 cannot be engaged with the operation lever 41 at the first position shown in FIG. 2, so that even if the valve plate 16 returns to the closed position, the operation lever 41 is held at the first position and the pressure release operation is detected. The switch operating portion 32a is held at the detection position. Therefore, the pressure release operation detection switch 30 is held in a state in which the pressure release operation detection signal is generated until the inspection and repair of the electrical equipment is completed and the operation lever holding piece 43 is engaged with the tip of the operation lever 41. . Therefore, for example, by providing a lamp that is lit when the pressure release operation detection switch 30 generates a detection signal, on the outside of the pressure release cylinder 1 or on a control panel of an electrical device, the pressure release film is not provided. However, it can be notified that the pressure release operation has been performed.

  After the electric device returns to the normal state, the operation lever 41 is rotated to the second position side, and the tip of the operation lever holding piece 43 is engaged with the tip of the operation lever 41, thereby operating the pressure release operation detection switch. The part 32a is returned to the non-detection position to prepare for the next pressure release operation.

  In the above embodiment, since the rotation of the movable shaft 15 is prevented by fitting the guide rod 17 and the guide hole 11c, the operation lever 41, the operation lever holding piece 43, and the like when the pressure release operation is performed. Can be prevented from shifting in the circumferential direction of the pressure release cylinder. Therefore, it is possible to easily perform the operation of engaging the operation lever 41 with the operation lever holding piece 43 after the electric device returns to the normal state. Further, it is possible to prevent the displacement of the movable shaft 15 from being caused by vibrations of the electrical equipment and the like so that the operation lever holding piece 43 is detached from the operation lever 41 and the pressure release operation detection switch performs the detection operation at the normal time.

  The means for preventing the rotation of the movable shaft 15 is not limited to the above example. For example, a key provided on the inner periphery of the hole 11a of the movable shaft support plate 11 is fitted in a key groove provided on the movable shaft 15. The movable shaft 15 may be prevented from rotating by combining them.

  Thus, in the present invention, since the pressure release operation detection signal can be obtained from the pressure release operation detection switch 30 even after the pressure release operation is completed, there is no need to provide a pressure release film that is destroyed during the pressure release operation. However, it is possible to leave a trace that the pressure release operation has been performed, and, as in the above-described embodiment, the pressure release film can be omitted to simplify the structure and reduce the cost.

  If the pressure release membrane is omitted, moisture may enter the pressure release cylinder 1 and condensation may occur in the valve plate 16 and the like in the pressure release cylinder. If the vent pipe 108 is connected, an air flow can be constantly generated through the pressure release cylinder 1 to keep the inside of the pressure release cylinder 1 in a dry state, thereby preventing condensation from occurring in the pressure release cylinder 1. be able to.

  In the above description, the pressure release cylinder 1 is connected to the tank of the electrical device via the connection pipe 4, but when the connection portion for connecting the pressure release cylinder 1 is integrally provided to the tank of the electrical device. The pressure release cylinder 1 may be directly connected to the connection portion.

  When the pressure release operation detection switch 30 is arranged in the container attached to the outside of the pressure release cylinder 1 as in the above embodiment, the diameter of the pressure release cylinder 1 is reduced to make the pressure release device compact. However, the present invention is not limited to such a configuration, and the case where the pressure release operation detection switch is disposed in the pressure release cylinder 1 is also included in the scope of the present invention.

It is the longitudinal cross-sectional view which showed the structure of one Embodiment of this invention. It is sectional drawing of the principal part which showed the state which the operating lever holding piece removed from the operating lever in embodiment of FIG.

DESCRIPTION OF SYMBOLS 1 Release cylinder 2 Release hole 3 Valve packing 15 Movable shaft 16 Valve plate 18 Release spring 22 Detection switch container 30 Release operation detection switch 31 Case of release operation detection switch 32 Operation part 41 of release operation detection switch Operation lever 43 Operation lever holding piece

Claims (4)

A pressure release cylinder having a pressure release hole on the rear end side and the rear end portion being connected to a tank of an electric device directly or via a connecting pipe, and opening and closing the pressure release hole from the inside of the pressure release cylinder A valve plate urged toward the side that opens the pressure release hole by the internal pressure when the internal pressure of the tank rises, and the pressure release cylinder coupled to the valve plate along with the displacement of the valve plate A movable shaft that is displaced in the axial direction, and a pressure release spring that biases the valve plate toward the side where the pressure release hole is closed, and the valve plate is moved when the pressure in the tank exceeds a limit value. In a pressure relief device for an electrical device that performs a pressure relief operation by displacing the pressure relief hole to the side that opens the pressure relief hole against the biasing force of the pressure relief spring,
A contact portion enclosed in a case, and an operation portion provided so as to be able to be displaced between a non-detection position and a detection position and causing the contact portion to perform a detection operation when the detection position is reached. A pressure release operation detection switch of a waterproof structure attached to the pressure release cylinder in a state where the operation portion is positioned in the pressure release cylinder;
When the pressure relief cylinder is supported so as to rotate between the first position and the second position and operate the operation portion of the pressure release operation detection switch, and reaches the first position. The operation part of the pressure release operation detection switch is provided to reach the detection position and return the operation part to the non-detection position in the process of rotating from the first position to the second position. Operating lever,
A lever urging spring that urges the operation lever to rotate to the first position;
To engage the operating lever when the valve plate is in a state before performing the pressure releasing operation and hold the operating lever in the second position against the biasing force of the lever biasing spring. And an operation lever holding piece attached to the movable shaft.
The operation lever holding piece can be engaged with the operation lever in the second position when the valve plate is in a position to close the pressure release hole, but the operation lever in the first position has It is provided so that it cannot be engaged, and is engaged with the operation lever when it is in a state before the pressure release operation is performed,
The operation lever holding piece is configured to be disengaged from the operation lever in accordance with the displacement of the movable shaft when the valve plate is displaced to the side of opening the pressure release hole to perform the pressure release operation.
A pressure relief device for electrical equipment. Outside the detection switch container peripheral wall portion of the discharge圧筒is Ri attached taken,
The pressure release operation detection switch is attached in a state where the case is accommodated in the detection switch container ,
2. The pressure relief device for an electric device according to claim 1, wherein the operation portion of the pressure relief operation detection switch is introduced into the pressure relief tube through a through hole formed in a peripheral wall portion of the pressure relief tube. apparatus.   The pressure relief device for an electric device according to claim 1 or 2, wherein a distal end side of the pressure relief cylinder is open to the atmosphere. The pressure relief cylinder is arranged with the tip side facing downward, and a vent pipe that communicates the inside of the pressure relief cylinder with outside air is connected to an upper part of the pressure relief cylinder,
Wherein the opening of the vent pipe, pressure-release device for electrical equipment according to claim 3, insect screen for preventing the insects from entering the圧筒release through the vent tube is attached.

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