Arc resistant louvre blade assembly applied to ventilation system of electrical enclosure

Abstract

The invention relates to an electrical system and an apparatus for use therewith. Further, the present invention provides a louvre blade assembly applied to a ventilation system of an electrical enclosure, where the louvre blade assembly includes a fixed frame. The fixed frame is attached to a ventilation hole in a wall of a ventilation input area. The louvre blade assembly further includes one or more louvre blades wherein each end of each louvre blade is attached to a connector that connects the fixed frame to a guide of the louvre blade assembly. The louvre blade assembly also includes a spring system attached to a top side of the frame. The louvre blade assembly also includes a locking mechanism disposed at an uppermost louvre blade of the one or more louvre blades.

Description

Technical Field

[0001] The present invention relates to electrical systems and the equipment used therein. Specifically, the present invention relates to an arc-resistant window leaf assembly that is used to improve safety and redirect debris, flames, plasma, and / or gases generated by the shock wave of an arc fault explosion in a variable frequency drive of an AC motor. Background Art

[0002] Medium voltage drives (also known as VFDs or variable frequency drives) are adjustable speed drives used to control the torque and speed of medium voltage AC motors. These drives are widely used in large industrial facilities such as wastewater treatment plants, petrochemicals, oil and gas, mining, food and pharmaceuticals, and general manufacturing.

[0003] The so-called medium voltage is a voltage up to approximately 15 kV. In this case, most medium voltage drives can be classified as voltage source inverter (VSI) type drives, which output an adjustable three-phase AC voltage.

[0004] It should be noted that medium voltage drives commonly found in large industrial facilities contain multiple interconnected power components that operate in coordination. Therefore, the risks associated with operating and maintaining such complex electrical equipment should not be overlooked.

[0005] Among the main risks posed by such equipment, arc fault explosion or arc flash is one of the most harmful risks to workers because this phenomenon releases a large amount of energy and generates high temperatures. Specifically, an arc fault explosion is a dangerous situation caused by an arc, which is caused by a phase-to-ground short circuit fault or an inter-phase short circuit fault. Arc fault explosion events release a large amount of energy in the form of thermal energy, toxic fumes, pressure and sound waves, blinding light, and explosions that can cause serious harm to the operator. In addition, the behavior of an arc in a three-phase system is considered chaotic because it involves rapid and irregular changes in the arc geometry due to convection, plasma jets, and electromagnetic forces.

[0006] Therefore, it is now more necessary to develop arc-resistant technologies in order to reduce the risk of injury caused by electrical equipment and protect personnel and equipment from the effects of arc fault explosion events that occur in electrical control panels (electrical panels) including medium voltage drives.

[0007] For example, in the case of overvoltage or fire occurring in the housing or cabinet of an electrical control panel with a medium voltage drive due to an electrical fault, there are some prior art documents that employ safety ventilation arrangements. However, there are still some deficiencies in such arrangements.

[0008] An exemplary system incorporating arc-resistant technology in an electrical module housing is discussed in the document US10,297,986B2. The document discloses an arc-resistant electrical enclosure that includes a barrier system that allows forced air cooling of the internal area during normal operation of the enclosure while preventing the flow of hot gases, plasma, and flames to the outside of the electrical enclosure in the event of an arc event or other event. The proposed barrier system includes a louver device and a cover device that work together to block the flow of gases, plasma, and flames to the outside of the cabinet in the event of an arc event. As described in the document, the louver device and the cover device (flame barrier layer) need to work together to withstand the debris and flames generated by an arc fault explosion. The drawback of the document is that the triggering of the mechanism is direct, that is, the shock wave and the increase in pressure generated by the explosion directly impact the louvers, and there is no auxiliary means for activating the system. Thus, since the explosion time is about 10 ms, when the louvers change from the open state to the closed state, the flames and debris will pass through due to the inertia of the louvers. In addition, the reference uses an additional protective measure formed by an aluminum honeycomb section that includes a coating located in front of the louvers to prevent flames from passing through.

[0009] In addition, the document US 9,6097,69B2 discloses a system that includes an enclosure having a ventilation opening and an isolation assembly. The isolation assembly includes a deformable portion and a blocking portion. The blocking portion is capable of substantially blocking the ventilation opening with a blocking surface. Thus, the arc-resistant mechanism employed in the document provides a metal plate that will plastically deform during an arc fault explosion event and block the ventilation opening of the electrical enclosure.

[0010] Finally, the document EP 2918154B1 illustrates an embodiment of an intake louver 300 for a power supply enclosure having an arc fault path in Figure 3. However, this arc-resistant mechanism is directly triggered by an arc explosion event from inside the electrical enclosure, which cannot appropriately prevent the escape of flames and debris. Summary of the Invention

[0011] The present invention stems from the industrial need to develop electrical control cabinets with arc-resistant features for medium voltage drives. Specifically, the present invention discloses a ventilation system that cools the electrical components inside the control cabinet during normal operation and, in the event of an arc fault explosion, closes its ventilation input due to the effect of the explosion itself, thereby providing a higher level of safety for nearby people and equipment. Thus, an object of the present invention is to provide a louver assembly that will automatically close using the overpressure and shock wave generated by an arc fault explosion.

[0012] In this sense, in one embodiment, the present invention provides a sash assembly for a ventilation system of an electrical enclosure, wherein the sash assembly includes a fixed frame. The fixed frame is attached to a ventilation hole in the wall of the ventilation input area. The sash assembly further includes one or more sashes, wherein each end of each sash is attached to a connector that connects the fixed frame to a guide of the sash assembly. The sash assembly further includes a spring system attached to the top side of the frame. The sash assembly further includes a locking mechanism disposed at the uppermost sash of the one or more sashes.

[0013] In addition, the present invention also provides a ventilation system for an electrical enclosure, wherein the ventilation system includes an arc-resistant sash assembly according to an embodiment of the present invention.

[0014] Furthermore, the present invention provides an electrical enclosure that includes an arc-resistant sash assembly according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In the drawings:

[0016] Figure 1 A perspective view of an exemplary electrical enclosure according to an embodiment of the present invention, the exemplary electrical enclosure including electrical equipment and a ventilation system therein;

[0017] Figure 2 A side view of the ventilation system within the electrical enclosure according to an embodiment of the present invention;

[0018] Figure 3A A perspective view of the sash assembly in an open state according to an embodiment of the present invention;

[0019] Figure 3B A side view of the sash assembly in an open state according to an embodiment of the present invention;

[0020] Figure 4A A perspective view of the sash assembly in a closed state according to an embodiment of the present invention;

[0021] Figure 4B A side view of the sash assembly in a closed state according to an embodiment of the present invention;

[0022] Figure 5A A perspective view of the sash assembly with a horizontal baffle in an open state according to an embodiment of the present invention;

[0023] Figure 5B A side view of the sash assembly with a horizontal baffle in an open state according to an embodiment of the present invention;

[0024] Figure 6A A perspective view of a window leaf assembly with a horizontal baffle in a closed state according to an embodiment of the present invention;

[0025] Figure 6B A side view of a window leaf assembly with a horizontal baffle in a closed state according to an embodiment of the present invention;

[0026] Figure 7A A perspective view of a window leaf assembly with an inclined baffle in an open state according to an embodiment of the present invention;

[0027] Figure 7B A side view of a window leaf assembly with an inclined baffle in an open state according to an embodiment of the present invention;

[0028] Figure 8A A perspective view of a window leaf assembly with an inclined baffle in a closed state according to an embodiment of the present invention;

[0029] Figure 8B A side view of a window leaf assembly with an inclined baffle in a closed state according to an embodiment of the present invention;

[0030] Figure 9A A cross-sectional view of a spring system and a locking mechanism in an open state according to an embodiment of the present invention;

[0031] Figure 9B A cross-sectional view of a spring system and a locking mechanism in a closed state according to an embodiment of the present invention. Detailed Description

[0032] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent that embodiments may be practiced without these specific details. The embodiments are disclosed in sections according to the following overview:

[0033] As used herein, an electrical "enclosure" (or "cabinet") shall be construed as the structure of an electrical control cabinet that includes a medium voltage drive and houses a plurality of interconnected power components operating in concert.

[0034] Additionally, expressions such as "flame", "fire", "smoke", "gas", "shock wave", "expansion wave", "fragment", etc. are generally used to refer to the products or consequences of an arc fault explosion and should be interpreted in a broad rather than a specific manner.

[0035] Typically, the electrical systems operating within these electrical enclosures are exposed to a high-risk phenomenon commonly known as arc flash or arc fault. There are several situations that can trigger an arc flash: for example, poor contact, degraded insulation, equipment defects, human error (improper design and installation, inadequate maintenance), and so on.

[0036] In an enclosed configuration, such as within such an enclosure, when an arc flash event occurs, the energy in the form of a shock wave caused by the explosion tends to propagate through the interior of the panel until it reaches the openings in the device, which are typically the openings in the ventilation system.

[0037] Therefore, the present invention proposes an arc-resistant louver assembly positioned in the ventilation system of an electrical enclosure, wherein, under normal operating conditions, the arc-resistant louver assembly contributes to the forced ventilation process driven by the fan of the ventilation system, thereby dissipating heat and cooling the internal components of the enclosure, and in the event of an arc flash (explosion), the louver assembly closes using the energy of the explosion itself, in the form of a shock wave caused by the melting of metal. In addition to closing the louvers to cover the ventilation input of the ventilation system, the debris and gases generated by the explosion are redirected to a safe area (ventilation output) through the design of the louver assembly, rather than moving towards some critical components or even the operator.

[0038] In this sense, Figure 1 Figure 100 shows an electrical enclosure according to an embodiment of the present invention.

[0039] Included in Figure 1 The ventilation system in the electrical enclosure 100 is shown in Figure 2 as an exemplary embodiment, wherein such a system is arranged in the upper region of the enclosure. The ventilation system plays a very important role in an electrical control cabinet because electrical components operating in a confined space environment require a suitable mechanism to continuously remove the heat they generate.

[0040] Figure 2 The ventilation system of Figure 2 includes a louver assembly 10, which is attached to the ventilation hole in the wall of the enclosure 100 and is arranged within the ventilation input area 20, through which air flows in the input direction 25 to cool the system under normal operating conditions. The ventilation system further includes a radiator 30 for absorbing excessive heat, a canalization 40, and a fan 50. Under normal operating conditions, air flows through the fan 50 in the output direction 55 to the ventilation output 60. Further, as can be exemplarily seen in

[0041] Now referring to Figure 3A and Figure 3B which disclose Figure 2 the window leaf assembly 10 in an open state of an exemplary embodiment of [[ID=]]. The window leaf assembly 10 includes a fixed frame 6 and one or more window leaves 1, the fixed frame 6 being attached to a ventilation hole in a wall of a ventilation input area 20. Each end of each window leaf 1 is attached to a connector 9, the connector 9 connecting the fixed frame 6 to a guide 2 of the window leaf assembly 10, wherein the guide 2 is axially movable to allow the one or more window leaves 1 to rotate together simultaneously when changing from an open state to a closed state during an arc fault event.

[0042] The window leaf assembly 10 further includes a spring system 3 attached to the top side of the frame 6 and a locking mechanism 7 disposed at the uppermost window leaf 1 among the one or more window leaves 1. The spring system 3 and the locking mechanism 7 are configured together to fix and hold the window leaf 1 in a closed state when an arc fault event occurs, as Figure 4A and Figure 4B shown in.

[0043] As shown in Figures 3A to 8B and more particularly as shown in Figure 9A and Figure 9B the spring system 3 includes a pin 3b placed within a spring 3a, the pin 3b being connected at its upper portion to a first formed plate 3c having a folded profile and at its lower portion to a second formed plate 3d such that the pin 3b passes through concentric holes in the plates 3c, 3d. The plates 3c, 3d form a U-shaped profile for fixing the pin 3b, and the spring 3a is accommodated between the first formed plate 3c and the second formed plate 3d. Preferably, there is a washer between the spring 3a and the second formed plate 3d. At the lower portion of the pin 3b, the pin is provided with a protrusion having a rounded end, the protrusion being configured to pass through a hole in the second formed plate 3d and a hole in the locking mechanism 7. When the window leaf 1 moves from an open state to a closed state, the spring movement will be activated, the spring 3a will rebound, and then when the rounded end of the pin 3b reaches a groove or hole release portion in the locking mechanism 7 before the protrusion passes through a hole in the distal portion of the locking mechanism 7, the spring 3a will return to its extended configuration, thereby locking the entire assembly and preventing the window leaf 1 from being opened again due to gravity or any other force that may be caused by an arc fault explosion.

[0044] In addition, Figure 3A , Figure 3B , Figure 4A and Figure 4BThe window leaf assembly 10 disclosed in [reference] further includes a rod 5 that is connected to one of the guides 2 at each end. The rod 5 acts as a driving device as it is configured to trigger the upward movement of the guides 2 so as to change the configuration of the window leaf assembly 10 from an open state to a closed state. The rod 5 is also configured to be manually triggered or triggered by any suitable device capable of contacting the rod 5, thereby forcing the entire structure to move upward.

[0045] Figures 5A to 8B A different embodiment of the window leaf assembly 10 is presented, which includes a baffle 4 located below one or more window leaves 1 and the rod 5. The baffle 4 is configured to act as a driving device working together with the rod 5 to close the window leaf 1, thereby preventing flames and debris from escaping through the ventilation input and causing serious damage to nearby people and equipment. Due to the load caused by the shock wave force generated by the arc fault explosion and originating from the area 70 (exemplarily shown in [reference]), the baffle 4 will deform and rotate around a weakened line 8 serving as the axis of rotation, which is located substantially away from the center of the baffle 4 and in the area near the edge. In other words, the baffle 4 is arranged to transfer the movement to the rod 5, thereby acting as a driver using the shock wave energy of the arc fault explosion. Additionally, the baffle 4 is also a mechanism for redirecting the flow of the expansion wave occurring inside the housing to another area of the system (e.g., the ventilation output 60). Furthermore, when redirecting the flow of the expansion wave, the baffle 4 also serves as an additional protection tool as the flames and debris will first impact the bottom part of the baffle 4 before hitting the window leaf 1. This greatly reduces the amount of debris that may escape through the window leaf 1. Figure 2 In addition, the baffle 4 also works together with the spring system 3 and the locking mechanism 7 as additional reinforcement to fix and hold the window leaf 1 in the closed state during an arc fault event.

[0046] Specifically,

[0047] Specifically, Figure 5A and Figure 5B The window leaf assembly 10 with a horizontal baffle 4 is shown when the window leaf 1 is in the open state. Thus, Figure 6A and Figure 6B The window leaf assembly 10 with a horizontal baffle 4 in a deformed configuration is presented when the window leaf 1 is in the closed state.

[0048] In an alternative embodiment of the present invention for Figures 5A - 6B In an alternative embodiment of the present invention, Figure 7A and Figure 7B The window leaf assembly 10 with an inclined baffle 4 is shown when the window leaf 1 is in the open state, while Figure 8A and Figure 8BShows a window leaf assembly 10 with an inclined baffle 4 in a deformed configuration when the window leaf 1 is in the closed state. For example, the inclined baffle 4 will be used in cases where a specific ventilation direction is required or an increased heat insulation distance is needed.

[0049] According to the present invention, Figure 5B and Figure 7B the opening angle α of the baffle can vary between about 0 degrees and about 180 degrees (when the baffle 4 is parallel to the horizontal plane) relative to the vertical axis to any angle between about 0 degrees and about 180 degrees, while Figure 6B and Figure 8B the closing angle β of the baffle is sufficient to safely close the window leaf.

[0050] From Figure 6A 、 Figure 6B 、 Figure 8A and Figure 8B the closing state embodiments, it can be inferred that when the baffle 4 plastically deforms, the baffle 4 also fixes the rod 5 in place. Therefore, both the baffle 4 and the spring system 3 are features that ensure that one or more window leaves 1 do not return to the open state due to gravity, and the window leaf returning to the open state due to gravity may cause fire or debris leakage.

[0051] In addition, although the foregoing embodiments are described by way of example assuming that the ventilation system is constructed in the upper region of the electrical enclosure 100, the present invention also provides that the window leaf assembly 10 with the baffle 4 can be installed in the lower region of the electrical enclosure 100. In this embodiment, the entire assembly will be placed upside down in an inverted position, where the baffle 4 is positioned above the rod 5 and the window leaf 1 to serve as a shield against shock waves from the upstream region of the enclosure 100. Therefore, the operating principle and technical features are consistent with the above. In summary, the window leaf assembly of the present invention can be installed in any side interface of the electrical enclosure in a conventional or inverted position.

[0052] Furthermore, the components of the above window leaf assembly can be made of any material, including metal alloys, polymers, ceramics, combinations thereof, or any other material suitable for working at high temperatures and withstanding shock waves.

[0053] When using metal alloys, any surface treatment or coating suitable for working at high temperatures can be used, such as electroplating, galvanizing, etc.

[0054] Although the subject matter has been described in language specific to structural features and / or method acts, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the above specific features or acts. On the contrary, the above specific features and acts are disclosed as example forms of implementing the claims.

Claims

1. A window leaf assembly, the window leaf assembly being applied to a ventilation system of an electrical enclosure, the window leaf assembly comprising: a fixed frame, the fixed frame being attached to a ventilation hole in a wall of a ventilation input area; one or more window leaves, wherein each end of each window leaf is attached to a connecting member, the connecting member connecting the fixed frame to a guide member of the window leaf assembly; a spring system, the spring system being attached to the top side of the frame; a locking mechanism, the locking mechanism being arranged at the uppermost window leaf of the one or more window leaves; and a baffle, the baffle being arranged to transfer motion to a rod, the rod being connected to one of the guide members at each end; the baffle being located below the one or more window leaves and the rod, wherein the baffle is configured to act as a driving device when using an arc fault explosion energy shock wave, the driving device working with the rod to close the window leaf.

2. The window leaf assembly according to claim 1, wherein, the guide member is axially movable to allow the one or more window leaves to rotate simultaneously together when changing from an open state to a closed state.

3. The window leaf assembly according to claim 1, wherein, the spring system includes a pin placed inside a spring, the pin being connected at its upper part to a first formed plate having a folded profile and at its lower part to a second formed plate such that the pin passes through concentric holes of the first formed plate and the second formed plate.

4. The window leaf assembly according to claim 3, wherein, the first formed plate and the second formed plate form a U-shaped profile for fixing the pin, and the spring is accommodated between the first formed plate and the second formed plate.

5. The window leaf assembly according to claim 3, wherein, the lower part of the pin is provided with a protrusion having a rounded end, the protrusion being configured to pass through a hole of the second formed plate and the locking mechanism.

6. The window leaf assembly according to claim 3, wherein, when the window leaf moves from the open state to the closed state, the movement of the spring will be activated and the spring will rebound, and then when the rounded end of the pin reaches a groove in the locking mechanism before the protrusion passes through the hole in the distal part of the locking mechanism, the spring will return to its extended configuration.

7. The window leaf assembly according to claim 1, wherein, the rod is configured to trigger the upward movement of the guide member so as to change the configuration of the window leaf assembly from an open state to a closed state.

8. The window leaf assembly according to claim 1, wherein, the spring system, the locking mechanism and the baffle acting together are configured to fix and hold the window leaf in a closed state.

9. The window leaf assembly according to claim 1, wherein, the baffle is configured to deform in response to a shock wave force from a downstream area and rotate around a weakening line, the weakening line being located in a region substantially away from the center of the baffle and near the edge.

10. The window leaf assembly according to claim 1, wherein, When the product of the arc-fault explosion impacts the bottom portion of the baffle, the baffle redirects the flow of the expansion wave occurring inside the electrical enclosure to another area of the ventilation system.

11. The sash assembly according to claim 1, wherein, the baffle is a horizontal baffle or an inclined baffle.

12. The sash assembly according to claim 11, wherein, the opening angle of the baffle can be changed between about 0 degrees and about 180 degrees relative to the vertical axis, and the closing angle of the baffle is sufficient to safely close the sash.

13. The sash assembly according to claim 1, wherein, when the baffle plastically deforms, the baffle fixes the rod in place.

14. The sash assembly according to claim 1, wherein, the sash assembly is further configured to be installed in any side interface of the electrical enclosure in a conventional or inverted position.

15. The sash assembly according to claim 1, wherein, the sash assembly, the spring system and the baffle can be made of any material, including metal alloys, polymers, ceramics, combinations thereof, or any other material suitable for working at high temperatures and withstanding shock waves.

16. A ventilation system for use in an electrical enclosure, wherein, the ventilation system includes the sash assembly according to claim 1.

17. An electrical enclosure, the electrical enclosure including the sash assembly according to claim 1.

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