Fusion tube with cooling capability for drop-out fuse

Abstract

The invention relates to a drop-out fuse tube with cooling capacity, and provides a drop-out fuse tube with cooling capacity based on the phenomena that a fuse wire is abnormally fused and the burnout fault of the fuse tube is increased during July and August every year when the air temperature is high, the electrical load is large and the load of a distribution transformer rises quickly in previous statistics. By arranging the rib with a unique structure on the surface of the fuse tube, the convection heat exchange area of the fuse tube is increased, the flow generated by natural convection is guided, and the convection heat exchange capability of the fuse tube is enhanced, so that the internal temperature of the fuse tube is reduced, the abnormal fusing of the fuse wire in the fuse tube and the burning of the fuse tube are prevented, and the reliability and the safety of the drop-out fuse are improved.

Description

Technical Field

[0001] The invention relates to the technical field of power systems, and in particular to a fusion tube for a drop-out fuse with cooling capability. Background Art

[0002] The safe operation of the power system is inseparable from overload protection equipment, among which drop-out fuses play a vital role. The core advantage of this device is that it can quickly cut off the circuit when the current exceeds the preset value, effectively ensuring the safety of equipment and lines. At the same time, because it has an obvious disconnection point, it can create a safe working environment for the maintenance section lines and equipment. Therefore, the reliability of drop-out fuses is of great significance to the power transmission safety of the power system. It can be clearly seen from previous statistics that in July and August each year, the temperature is high, the power load is large, and the distribution transformer load rises rapidly, and the fuse fuse failure is concentrated and frequent. This shows that there is an abnormal fuse fuse. One of the reasons is that with the increase of ambient temperature, the temperature rise of the fuse in the fuse tube is obvious, resulting in long-term overheating and melting of the fuse. In addition, when the fuse tube is working normally and takes protective action, a large amount of high-temperature gas is generated, which requires the fuse tube to be not only flame retardant, but also to prevent the fuse tube from burning. The fuse tube is in a high temperature state, which is prone to burnout fuse failure.

[0003] The analysis of the abnormal melting failure of the fuse in the fuse tube found that the main reason is: the fuse tube of the common drop-out fuse uses a light tube, which has poor heat exchange capacity, causing the temperature inside the fuse tube to be seriously higher than the ambient temperature. The high temperature environment is not conducive to the normal operation of the fuse. The fuse often melts when the current does not exceed the rated current, causing various losses and waste of resources. Therefore, in order to solve this common problem, it is necessary to design a fuse tube for drop-out fuses with cooling capacity. Summary of the invention

[0004] The present invention is based on the principle of increasing the heat transfer area of ​​the outer surface of the fuse tube and guiding the natural convection flow to enhance the heat transfer. A fin with a unique structure is arranged on the surface of the fuse tube to enhance the convection heat transfer capacity of the fuse tube, reduce the internal temperature of the fuse tube, and make the fuse work at a lower temperature, so as to prevent the fuse from melting when the current does not exceed the rated current due to the accumulation of heat in the fuse tube, solve the common problem of the fuse tube being easily burned, and improve the reliability of the power system.

[0005] The technical solution of the present invention is as follows: the melting tube is equipped with fins for expanding the outer surface area of ​​the melting tube and guiding the natural convection flow direction. The airflow generated by natural convection takes away the heat through the outer surface of the melting tube and the surface of the fin. The fins are provided with convex corrugations and concave corrugations to further enhance the heat transfer. The through hole intersecting the outer surface of the melting tube is an elliptical inner hole. The inner hole major axis of the elliptical inner hole is along the gravity direction, and the inner hole minor axis is parallel to the ground. The outer edge shape of the fin is an ellipse, and the major axis of the ellipse is also along the gravity direction, and the minor axis is also parallel to the ground. Such a structure can ensure that the large surface of the fin is perpendicular to the horizontal plane, which is conducive to generating strong natural convection on the large surface of the fin and enhancing convective heat transfer.

[0006] The major axis of the elliptical inner hole is d / cos( α ),here d is the outer diameter of the melt tube, and the short axis length of the inner hole is d , α is the angle between the axis of the melting tube and the horizontal plane, and the major axis of the ellipse is d / cos( α )of β times, the minor axis is (1+(β-1)cos(α))× d ,here β The value range is 1.2-1.8. α The value of is the angle between the axis of the insulator and the horizontal plane after installation.

[0007] The crest line of the convex corrugation on fin 2 is 0.5 (1 + β )× d / cos(α)+ a is the major axis, 0.5 (2 + β )× d + a On an ellipse with the minor axis, the trough line of the concave ripple is at 0.5 (1 + β )× d / cos( α )- a is the major axis, 0.5 (2+ β )× d - a For an ellipse with a minor axis, the length of the peak line is d / cos( α ), the length of the trough line is d / cos( α ), a is the width of the convex corrugation and the concave corrugation. The intersection line of the convex corrugation and the tangent plane passing through the minor axis of the ellipse and perpendicular to the major axis of the ellipse can be a variety of lines, such as an arc. The intersection line of the concave corrugation 4 and the tangent plane passing through the minor axis of the ellipse and perpendicular to the major axis of the ellipse can be a variety of lines, such as an arc. The amplitude of the convex corrugation 3 and the concave corrugation 4 is h , with a value of 0.6a ~0.8 a Such a structure increases the disturbance of natural convection flow and improves the convection heat transfer coefficient of the fin surface by 1.15 to 1.2 times.

[0008] The elliptical inner hole has a ring boss to locate the spacing between adjacent fins p f , p f At 0.2 d ~0.5 d The value is between 1.5 mm and 2.5 mm, and the thickness of the fin is 1.5 mm to 2.5 mm. This ensures that the fin has a higher fin efficiency, improves the effectiveness of fin area heat transfer, and increases the heat transfer surface area of ​​the outer melting tube by more than 3 times. The fin material is selected to be easy to connect with the melting tube, and the connection method can be adhesive technology, etc., which ensures a higher fin fin efficiency and reduces the contact thermal resistance between the fin and the melting tube. .

[0009] The beneficial effects of the present invention are as follows: a rib with a unique structure is arranged on the surface of the fuse tube to increase the convection heat exchange area of ​​the fuse tube, guide the flow generated by natural convection, enhance the convection heat exchange capacity of the fuse tube, reduce the internal temperature of the fuse tube, prevent the fuse in the fuse tube from abnormally melting and burning, thereby improving the reliability and safety of the drop-out fuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings provide a schematic diagram of the structure of such a melting tube, wherein: Figure 1 The overall structure of a drop-out fuse equipped with a cooling-capacity fuse tube; Figure 2 Melt tube structure with cooling capability; Figure 3 Fin structure; Figure 4 Concave and convex corrugation arrangement; Figure 5 yes Figure 4 The I-I section shows the dimensions of the convex-concave corrugated structure. DETAILED DESCRIPTION

[0011] An embodiment of the present invention relates to a drop-out fuse equipped with a cooling-capable fuse tube. After manufacturing the fin 2 according to the fin structure of the present invention, the fin 2 and the fuse tube 1 are connected through a certain process to form the drop-out fuse tube with cooling capacity described in the present invention.

[0012] The melting tube 1 is provided with fins 2 for expanding the outer surface area of ​​the melting tube 1 and guiding the natural convection flow direction. The airflow generated by natural convection takes away the heat through the outer surface of the melting tube 1 and the surface of the fin 2. The fin 2 is provided with convex corrugations 3 and concave corrugations 4 to further enhance the heat transfer. The through hole intersecting the outer surface of the melting tube 1 is an elliptical inner hole 5. The inner hole major axis 6 of the elliptical inner hole 5 is along the direction of gravity, and the inner hole minor axis 7 is parallel to the ground. The outer edge shape of the fin 2 is an ellipse 8. The major axis 9 of the ellipse 8 is also along the direction of gravity, and the minor axis 10 is also parallel to the ground.

[0013] The major axis 6 of the elliptical inner hole 5 is d / cos( α ),here d is the outer diameter of the melting tube, and the length of the inner hole short axis 7 is also d , α is the angle between the axis of the melting tube and the horizontal plane, and the major axis 9 of the ellipse 8 is d / cos( α )of β times, the minor axis 10 is (1+(β-1)cos(α))× d ,here β The value range is 1.2-1.8. α The value of is the angle between the axis of the insulator 11 and the horizontal plane after installation.

[0014] The peak line 12 of the convex ripple 3 is at 0.51 + β × d / cos(α)+ a For the long axis, 0.52 + β × d + a On the ellipse with the minor axis, the trough line 13 of the concave corrugation 4 is at 0.51 + β × d / cos( α )- a For the long axis, 0.52+ β × d - a On the ellipse with the minor axis, the length of the peak line 12 is d / cos( α ), the length of the trough line 13 is d / cos( α ), a It is the width 14 of the convex corrugation 3 and the concave corrugation 4.

[0015] The convex corrugation 3 is tangent to a plane passing through the minor axis of the ellipse and perpendicular to the major axis of the ellipse to form a convex corrugation intersection line 15, which is an arc shape. The concave corrugation 4 is tangent to a plane passing through the minor axis of the ellipse and perpendicular to the major axis of the ellipse to form a concave corrugation intersection line 16, which is an arc shape. The amplitudes of the convex corrugation 3 and the concave corrugation 4 are h ,h The value is 0.6 a ~0.8 a , a It is the width 14 of the convex corrugation 3 and the concave corrugation 4.

[0016] The elliptical inner hole 5 of the fin 2 has a ring boss 17 to locate the spacing between adjacent fins 2 p f 18, p f At 0.2 d ~0.5 d The thickness of the fin 2 is 1.5 mm to 2.5 mm.

[0017] The following are the specific implementation details: According to the material of the melting tube, the material of the fin 2 is selected, and the connection method of the melting tube 1 and the fin 2 is selected, which can be a gluing process.

[0018] Draw the fin 2 drawing according to the dimensions determined by the above technical content description.

[0019] The fin 2 is processed according to the designed fin 2 drawing, which includes the formulation of manufacturing process and the design and processing of tooling equipment.

[0020] Design the assembly process and tooling equipment of the melting tube 1 and the fin 2, pass the fin 2 onto the melting tube 1, and position the fin around the boss.

[0021] The melting tube 1 and the fin 2 are connected by a suitable bonding process to form the melting tube of the present invention.

[0022] The manufacturing process of the fin 2 and the assembly process of the melting tube 1 and the fin 2 use existing materials in the prior art, and the techniques such as cutting and pressing during production and gluing during assembly are all existing techniques, so they will not be described in detail in the embodiments.

Claims

1. A melting tube with cooling capability for a drop-out fuse, characterized in that: The molten tube (1) is provided with fins (2) for expanding the outer surface area of ​​the molten tube (1) and guiding the flow direction of natural convection. The airflow generated by natural convection passes through the outer surface of the molten tube (1) and the surface of the fin (2) to take away heat. The fin (2) is provided with convex corrugations (3) and concave corrugations (4) to further enhance heat transfer. The through hole intersecting the outer surface of the molten tube (1) is an elliptical inner hole (5). The inner hole major axis (6) of the elliptical inner hole (5) is along the direction of gravity, and the inner hole minor axis (7) is parallel to the ground. The outer edge shape of the fin (2) is an ellipse (8). The major axis (9) of the ellipse (8) is also along the direction of gravity, and the minor axis (10) is also parallel to the ground.

2. A fusion tube with cooling capability for a drop-out fuse according to claim 1, characterized in that: The major axis (6) of the elliptical inner hole (5) is d / cos( α ),here d is the outer diameter of the melting tube, and the length of the inner hole short axis (7) is also d , α is the angle between the axis of the melting tube and the horizontal plane, and the major axis (9) of the ellipse (8) is d / cos( α )of β times, the minor axis (10) is (1+(β-1)cos(α))× d ,here β The value range is 1.2 ～ 1.8, α The value of is the angle between the axis of the insulator (11) and the horizontal plane after installation.

3. A melting tube with cooling capability for a drop-out type fuse according to claim 2, characterized in that: The peak line (12) of the convex ripple (3) is 0.5 (1 + β )× d / cos(α)+ a is the major axis, 0.5 (2 + β )× d + a On the ellipse with the minor axis as the minor axis, the trough connecting line (13) of the concave corrugation (4) is at 0.5 (1 + β )× d / cos( α )- a is the major axis, 0.5 (2+ β )× d - a For an ellipse with a minor axis, the length of the peak connecting line (12) is d / cos( α ), the length of the trough line (13) is d / cos( α ), a is the width (14) of the convex corrugation (3) and the concave corrugation (4).

4. A melting tube with cooling capability for a drop-out type fuse according to claim 2, characterized in that: The intersection line (15) of the convex corrugation (3) and the convex corrugation tangent to the plane passing through the minor axis of the ellipse and perpendicular to the major axis of the ellipse is in the shape of an arc, and the intersection line (16) of the concave corrugation (4) and the concave corrugation tangent to the plane passing through the minor axis of the ellipse and perpendicular to the major axis of the ellipse is in the shape of an arc. The amplitudes of the convex corrugation (3) and the concave corrugation (4) are h , h The value is 0.6 a～ 0.8 a , a is the width (14) of the convex corrugation (3) and the concave corrugation (4).

5. A cooling-capable fuse tube for a drop-out fuse according to claim 2, characterized in that: the elliptical inner hole (5) of the fin (2) has a ring boss (17) to locate the spacing between adjacent fins (2) p f (18), p f At 0.2 d～ 0.5 d Take a value between.

6. A cooling-capable fuse tube for a drop-out fuse according to claim 5, characterized in that: the thickness of the fin (2) is 1.5 mm ～ 2.5 mm.

7. A cooling-capable fuse tube for a drop-out fuse according to claim 1, wherein the fin (2) is made of a material that is easily connected to the fuse tube, and the connection is made by gluing.

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