Fuse and surge protector

Abstract

The utility model relates to the field of surge protector equipment, in particular to a fuse and a surge protector. The fuse provided by the utility model is used for backup protection of a surge protector body and comprises a fusing piece and a heating piece, the fusing piece is used for being connected with the surge protector body in series, the heating piece is matched with the fusing piece, and the heating piece is used for heating the surge protector body when power frequency current passes through a lightning protection circuit where the surge protector body is located. And the fuse element is fused by electrifying and generating heat, so that the lightning protection circuit is disconnected. The impact current resistance of the fuse can be improved.

Description

Technical Field

[0001] The utility model relates to the field of surge protector equipment, in particular to a fuse and a surge protector. Background Art

[0002] The function of the surge protector body is to protect the line it is connected to. The surge protector body is used in electrical circuits or communication lines. Its principle is to realize the conduction and shunting of the impact current through the internal varistor, so as to avoid the impact current from damaging the equipment on the electrical circuit or communication line. The varistor may deteriorate after long-term use. In the traditional solution, a thermal trip component is provided in the surge protector body used in the electrical circuit. When the varistor deteriorates and the surge protector body is subjected to a continuous small current impact, the thermal trip component can disconnect the connection between the line and the ground wire by fusing, thereby achieving the purpose of thermal tripping; when the varistor of the surge protector deteriorates to a certain extent and the power frequency current flowing through the surge protector is large, the thermal trip component of the surge protector cannot trip before being damaged by heat for the large power frequency current. Therefore, the surge protector body is protected by connecting it in series with the fuse. Specifically, when the power frequency current flows through the fuse, the circuit in the fuse is disconnected, thereby avoiding the heat generated by the power frequency circuit causing the surge protector body to burn.

[0003] The defect of the above scheme is that the surge protector body is connected in series with the fuse. When the industrial frequency current flows through, the resistance of the varistor of the surge protector body is still large after deterioration to a certain extent, so the current flowing through the fuse is small. To make the fuse blow, a model with a smaller rated current is required. When the impact current flows through the surge protector body, it will inevitably flow through the fuse, which may cause the circuit in the fuse with a smaller rated current to be disconnected. Therefore, the fuse in the above scheme has poor impact current resistance. Utility Model Content

[0004] On the one hand, the utility model provides a fuse that can improve the ability of the fuse to withstand impact current;

[0005] On the other hand, the utility model provides a surge protector.

[0006] The fuse provided by the utility model is used for backup protection of a surge protector body, and comprises a fuse and a heating element. The fuse is used to be connected in series with the surge protector body, and the heating element cooperates with the fuse. When the lightning protection circuit where the surge protector body is located passes through the industrial frequency current, the heating element is energized to generate heat to melt the fuse, so that the lightning protection circuit is disconnected.

[0007] Furthermore, the fuse element includes a fuse part, and the heating element includes an electrode end, the electrode end cooperates with the fuse part, and the electrode end is used to generate an electric arc to melt the fuse part.

[0008] Furthermore, the fuse includes a fusible wire for forming the fuse element, and also includes an ignition electrode for forming the heating element, the fusible wire has a first connection end and a second connection end, and a low melting point block for forming the fuse part is provided on the fusible wire located between the first connection end and the second connection end, and the ignition electrode includes a first electrode and a second electrode, and the ends of the first electrode and the second electrode are respectively located on both sides of the low melting point block to form the electrode end.

[0009] Furthermore, the fuse also includes a tube body and two fuse caps, the tube body is provided with a cavity with openings at both ends, the fuse wire and the ignition electrode are located in the cavity, the two fuse caps are respectively arranged at the two openings and are sleeved with the tube body, and the first connection end and the second connection end of the fuse wire are respectively connected to the corresponding fuse caps.

[0010] Furthermore, the low melting point block has a connecting hole, and the ends of the first electrode and the second electrode both correspond to the connecting hole.

[0011] Furthermore, the inner wall of the communicating hole forms a tip structure.

[0012] The surge protector provided by the utility model comprises the fuse as described in any one of the above items.

[0013] Furthermore, the surge protector also includes a surge protector body and a control circuit. The surge protector body and the fuse are connected in series to the lightning protection circuit. The heating element is arranged on the control circuit. The control circuit can draw power from the lightning protection circuit.

[0014] Furthermore, a current transformer is provided between the lightning protection circuit and the control circuit, the current transformer includes a primary side and a secondary side, the primary side is connected in series to the lightning protection circuit, and the secondary side is connected in series to the control circuit.

[0015] Furthermore, along the direction from the power supply line to the ground, the current transformer, the surge protector body and the fuse are sequentially arranged on the lightning protection circuit.

[0016] Beneficial Effects

[0017] The fuse in this solution is connected in series with the lightning protection circuit where the surge protector body is located, and the heating element can draw power from the lightning protection circuit. When the power frequency current flows through the lightning protection circuit where the surge protector body is located, the heating element generates heat and melts the fuse. Compared with the traditional solution in which the surge protector body is connected in series with the fuse, when the power frequency current flows through, the current flowing through the fuse is small due to the large resistance of the varistor of the surge protector body. To make the fuse melt, a model with a smaller rated current is required. When the impact current flows through the surge protector body, it will inevitably flow through the fuse, which may cause the circuit in the fuse with a smaller rated current to be disconnected. Therefore, the fuse has poor impact current resistance. In this solution, only the fuse is connected in series with the circuit where the surge protector body is located. The heating element can be made of a material with a higher heating temperature under the same current conditions. Since the heating element can provide a higher melting temperature, a fuse with a higher rated temperature can be selected, thereby avoiding the impact current from disconnecting the circuit in the fuse, and improving the impact current resistance of the fuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 It is an overall schematic diagram of the fuse provided in the first and second embodiments of the present utility model;

[0020] Figure 2 It is a structural schematic diagram of the fuse part provided in the first and second embodiments of the present utility model;

[0021] Figure 3 This is a circuit diagram provided by Embodiment 1 and Embodiment 2 of the present utility model.

[0022] Figure numbers: 1-fuse; 2-heating element; 3-tube body; 4-fusible core cap; 5-fuse wire; 6-low melting point block; 7-connecting piece; 8-lightning protection circuit; 9-first electrode; 10-second electrode; 11-tip structure; 12-connecting hole; 13-current transformer; 14-surge protector body; 15-control circuit. DETAILED DESCRIPTION

[0023] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0024] Embodiment 1

[0025] like Figures 1 to 3 As shown, a fuse is used for backup protection of a surge protector body 14, including a fuse 1 and a heater 2. The fuse 1 is used to be connected in series with the surge protector body 14, and the heater 2 cooperates with the fuse 1. The heater 2 is used to generate heat to melt the fuse 1 when the lightning protection circuit 8 where the surge protector body 14 is located passes the industrial frequency current, so that the lightning protection circuit 8 is disconnected.

[0026] The function of the surge protector body 14 is to protect the line it is connected to. The surge protector body 14 is used in the power supply circuit or communication line. Its principle is to realize the conduction and shunting of the impact current through the internal varistor, so as to avoid the impact current from damaging the equipment on the power supply circuit or communication line. The varistor may deteriorate after long-term use. In the traditional solution, a thermal trip component is provided in the surge protector body 14 used in the power supply circuit. When the varistor deteriorates and the surge protector body 14 is subjected to a continuous small current impact, the thermal trip component can disconnect the connection between the line and the ground wire by fusing, thereby achieving the purpose of thermal tripping; and for the power frequency current, the surge protector body 14 is protected by connecting it in series with the fuse. Specifically, when the power frequency current flows through the fuse, the circuit in the fuse is disconnected, thereby avoiding the heat generated by the power frequency circuit causing the surge protector body 14 to burn. The defect of the above scheme is that the surge protector body 14 is connected in series with the fuse. When the power frequency current flows through it, the current flowing through the fuse is small due to the large resistance of the varistor of the surge protector body 14. In order to make the fuse blow, a model with a smaller rated current is required. When the impact current flows through the surge protector body 14, it will inevitably flow through the fuse, which may cause the circuit in the fuse with a smaller rated current to be disconnected. Therefore, the fuse in the above scheme has poor impact current resistance. Compared with the above scheme, the fuse 1 in this scheme is arranged in series on the lightning protection circuit 8 where the surge protector body 14 is located, and the heating element 2 can draw power from the lightning protection circuit 8. When the power frequency current flows through the lightning protection circuit 8 where the surge protector body 14 is located, the heating element 2 generates heat and melts the fuse 1. Compared with the traditional scheme, the power frequency current directly flows to the fuse through the surge protector body 14, and the fuse element 5 in the fuse melts due to self-heating. In the fuse of this scheme, only the fuse 1 is connected in series on the circuit where the surge protector body 14 is located. The heating element 2 can be made of a material with a higher heating temperature under the same current conditions. Since the heating element 2 can provide a higher melting temperature, a fuse 1 with a higher rated temperature can be selected to avoid the impact current from disconnecting the circuit in the fuse.

[0027] In an optional embodiment, the fuse 1 includes a fuse part, and the heating element 2 includes an electrode end, which cooperates with the fuse part and is used to generate an arc to melt the fuse part.

[0028] The first connection end and the second connection end of the fuse 1 are respectively connected to the lightning protection circuit 8, and the fuse part is located between the first connection end and the second connection end. When the fuse part blows, the part between the first connection end and the second connection end of the fuse 1 can be disconnected, so that the lightning protection circuit 8 is disconnected.

[0029] The electrode end of the heating element 2 generates an arc, and the arc acts on the fuse part to disconnect the fuse element 1.

[0030] Alternatively, the heating element 2 includes an electric heating wire, which cooperates with the fuse part. When the electric heating wire is energized, it generates heat to fuse the fuse part.

[0031] In an optional embodiment, the fuse includes a fusible wire 5 for forming a fuse element 1, and also includes an ignition electrode for forming a heating element 2, the fusible wire 5 has a first connection end and a second connection end, and a low melting point block 6 for forming a fuse part is provided on the fusible wire 5 between the first connection end and the second connection end, and the ignition electrode includes a first electrode 9 and a second electrode 10, and the ends of the first electrode 9 and the second electrode 10 are respectively located on both sides of the low melting point block 6 for forming an electrode end.

[0032] The two ends of the fuse 5 along the length direction are respectively the first connection end and the second connection end. Preferably, the fuse 5 is a thin sheet structure, and a low melting point block 6 is embedded in the thin sheet structure. The first electrode 9 and the second electrode 10 are respectively connected to the control circuit 15. The first electrode 9 and the second electrode 10 are respectively located on the upper and lower sides of the fuse 5. The end of the first electrode 9 and the end of the second electrode 10 form electrode ends relative to each other. Specifically, a gap is formed between the end of the first electrode 9 and the end of the second electrode 10, and the low melting point block 6 is located in the gap. When the control circuit 15 where the first electrode 9 and the second electrode 10 are located is energized, an arc appears in the gap between the first electrode 9 and the second electrode 10, and the arc melts the low melting point block 6, and its heat continues to melt the fuse 5.

[0033] In an optional embodiment, the fuse also includes a tube body 3 and two fuse caps 4. The tube body 3 is provided with a cavity with openings at both ends. The fuse 5 and the ignition electrode are located in the cavity. The two fuse caps 4 are respectively arranged at the two openings and are sleeved with the tube body 3. The first connection end and the second connection end of the fuse 5 are respectively connected to the corresponding fuse cap 4.

[0034] The function of the tube body 3 is to support and protect the conductive sheet and the electric heating wire in the second tube cavity. The tube body 3 is made of ceramic or glass, and the two ends of the tube body 3 are respectively sleeved with fuse caps 4, which block the two end openings of the cavity, and fix the conductive sheet through the connecting piece 7. Specifically, a connecting piece 7 is provided on the inner wall of each fuse cap 4, one end of the connecting piece 7 is welded to the fuse cap 4, and the other end is welded to the fuse 5. The two ends of the fuse 5 correspond to the connecting piece 7, so that the fuse 5 is fixed in the cavity.

[0035] The first electrode 9 and the second electrode 10 pass through the tube body 3 respectively and are fixed to the wall of the tube body 3. The fuse cap 4 and the connecting piece 7 are made of conductive materials. When the impulse current passes through the fuse, it passes through the fuse cap 4 and the connecting piece 7 at one end, passes through the fuse wire 5, and finally passes through the connecting piece 7 and the fuse cap 4 at the other end.

[0036] Alternatively, the first electrode 9 and the second electrode 10 pass through the fuse cap 4 respectively, and the first electrode 9 and the second electrode 10 are insulated and fixed to the fuse cap 4 .

[0037] In an optional embodiment, the low melting point block 6 has a connecting hole 12 , and the ends of the first electrode 9 and the second electrode 10 both correspond to the connecting hole 12 .

[0038] The low melting point block 6 is embedded in the fuse 5, and the connecting hole 12 on the low melting point block 6 penetrates the low melting point block and the fuse 5. The end of the first electrode 9 and the end of the second electrode 10 are opposite to the connecting hole 12. When a voltage is generated between the first electrode 9 and the second electrode 10, the arc between the first electrode 9 and the second electrode 10 passes through the connecting hole 12.

[0039] In an optional embodiment, the inner wall of the communicating hole 12 forms a tip structure 11 .

[0040] The connecting hole 12 is a circular hole, and the inner wall of the hole is formed by two annular surfaces. There is an angle between the two annular surfaces, and the inner wall of the hole forms a tip structure 11 facing the axial direction. When the arc between the first electrode 9 and the second electrode 10 passes through the connecting hole 12, the thickness of the end of the tip structure 11 close to the arc is smaller along the axial direction, so heat is easily accumulated, thereby facilitating melting.

[0041] Embodiment 2

[0042] The surge protector provided by the utility model comprises any fuse as described above.

[0043] In an optional embodiment, the surge protector also includes a surge protector body 14 and a control circuit 15. The surge protector body 14 and the fuse 1 are connected in series to the lightning protection circuit 8. The heating element 2 is arranged on the control circuit 15. The control circuit 15 can draw power from the lightning protection circuit 8.

[0044] The fuse in the present scheme is arranged in series on the lightning protection circuit 8, and the surge protector body 14 is also connected in series on the lightning protection circuit 8. An electric element is provided on the control circuit 15, and the electric element can control whether the control circuit 15 is energized according to the current electrical parameters of the lightning protection circuit 8. When the industrial frequency current flows through the lightning protection circuit 8, the electric element energizes the control circuit 15 according to the preset conditions. The power source is the lightning protection circuit 8. After the control circuit 15 is energized, the heating element 2 transfers heat to the fuse 1 by electric arc or heat generation.

[0045] In an optional implementation, a current transformer 13 is provided between the lightning protection circuit 8 and the control circuit 15 . The current transformer 13 includes a primary side and a secondary side. The primary side is connected in series to the lightning protection circuit 8 , and the secondary side is connected in series to the control circuit 15 .

[0046] When a large overcurrent appears on the lightning protection circuit 8 where the surge protector body 14 is located, the secondary side of the through-core current transformer 13 outputs a control current, and a voltage is generated between the first electrode 9 and the second electrode 10 on the control circuit 15. When the voltage exceeds the threshold, an arc is generated between the first electrode 9 and the second electrode 10. The arc heats the low-melting-point block 6 to melt it, and then blows the fuse 5. Since the fuse 5 is connected in series to the lightning protection circuit 8, the lightning protection circuit 8 is disconnected. At this time, the power frequency current on the lightning protection circuit 8 is disconnected, and no voltage is generated on the secondary side of the current transformer 13, and the arc between the first electrode 9 and the second electrode 10 disappears.

[0047] In an optional implementation, along the direction from the power line to the ground, the current transformer 13, the surge protector body 14 and the fuse 1 are sequentially arranged on the lightning protection circuit 8.

[0048] It should be noted that any of the above embodiments is illustrative of the present invention rather than limiting the present invention, and that those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets should not be constructed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of multiple such elements. The present invention may be implemented by means of hardware comprising several different elements and by means of appropriately programmed computers. In a unit claim that lists several devices, several of these devices may be embodied by the same hardware item. The use of the words primary, secondary, previous, and next, etc. does not indicate any order. These words may be interpreted as names.

[0049] The above implementation modes are only suitable for illustrating the present invention, but not for limiting the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The scope of patent protection of the present invention should be limited by the claims.

Claims

1. A fuse for backup protection of a surge protector body (14), characterized in that: The invention comprises a fuse (1) and a heating element (2), wherein the fuse (1) is connected in series with a surge protector body (14), and the heating element (2) cooperates with the fuse (1), and the heating element (2) is used to generate heat to melt the fuse (1) when a power frequency current passes through a lightning protection circuit (8) where the surge protector body (14) is located, so as to disconnect the lightning protection circuit (8); The fuse (1) comprises a fuse part, and the heating element (2) comprises an electrode end, the electrode end cooperates with the fuse part, and the electrode end is used to generate an electric arc to melt the fuse part; The fuse comprises a fusible wire (5) for forming the fusible element (1), and also comprises an ignition electrode for forming the heating element (2), the fusible wire (5) having a first connection end and a second connection end, a low melting point block (6) for forming the fusible part is provided on the fusible wire (5) between the first connection end and the second connection end, and the ignition electrode comprises a first electrode (9) and a second electrode (10), the ends of the first electrode (9) and the second electrode (10) are respectively located on both sides of the low melting point block (6) for forming the electrode end.

2. The fuse according to claim 1, characterized in that: The fuse further comprises a tube body (3) and two fusible core caps (4); a cavity with openings at two ends is provided in the tube body (3); the fusible wire (5) and the ignition electrode are located in the cavity; the two fusible core caps (4) are respectively arranged at the two openings and are sleeved with the tube body (3); the first connection end and the second connection end of the fusible wire (5) are respectively connected to the corresponding fusible core caps (4).

3. The fuse according to claim 1, characterized in that: The low melting point block (6) has a connecting hole (12), and the ends of the first electrode (9) and the second electrode (10) both correspond to the connecting hole (12).

4. The fuse according to claim 3, characterized in that: The inner wall of the communicating hole (12) forms a tip structure (11).

5. A surge protector, characterized in that: Comprising the fuse as claimed in claim 1.

6. The surge protector according to claim 5, characterized in that: The surge protector further comprises a surge protector body (14) and a control circuit (15); the surge protector body (14) and the fuse (1) are connected in series to a lightning protection circuit (8); the heating element (2) is arranged on the control circuit (15); and the control circuit (15) can draw power from the lightning protection circuit (8).

7. The surge protector according to claim 6, characterized in that: A current transformer (13) is provided between the lightning protection circuit (8) and the control circuit (15), the current transformer (13) comprising a primary side and a secondary side, the primary side being connected in series to the lightning protection circuit (8), and the secondary side being connected in series to the control circuit (15).

8. The surge protector according to claim 7, characterized in that: In a direction from the power supply line to the ground, the current transformer (13), the surge protector body (14) and the fuse (1) are arranged in sequence on the lightning protection circuit (8).

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