A resistance tube for a load which prevents overheating and is easy to identify a failure

Abstract

The application relates to the technical field of resistance tubes, in particular to a resistance tube for load which is resistant to overheating and easy to identify faults, which comprises a metal outer tube and a resistance wire arranged in the metal outer tube, the metal outer tube is filled with insulating powder, so that the resistance wire is separated from the inner wall of the metal outer tube, the end of the metal outer tube is provided with a PTC resistance and an outgoing terminal, one end of the PTC resistance is connected with the resistance wire, the other end of the PTC resistance is connected with the outgoing terminal, the outgoing terminal extends out of the metal outer tube, and the PTC resistance and the inner wall of the metal outer tube are mutually insulated; an induction coil is arranged on the outgoing terminal outside the port of the metal outer tube, the induction coil is connected with an indicating lamp; an annular expansion body is sleeved outside the PTC resistance, a deformation part is arranged on the section of the metal outer tube corresponding to the expansion body, so that the expansion body is expanded outward to push up the deformation part to form a bulge after the expansion body is heated to a preset temperature, and the expansion body and the deformation part are mutually insulated. The position of the faulty resistance tube can be quickly located, and the faulty resistance tube can be replaced.

Description

Technical Field

[0001] This invention relates to the field of resistance tube technology, and more specifically to a load resistance tube that is resistant to overheating and easy to identify faults. Background Technology

[0002] With the development of power electronics, the requirements for equipment integration and load performance are becoming increasingly stringent. As a key component of the load, the stability and safety of resistors are of paramount importance. During use, resistors often overheat and burn out, potentially damaging other components and causing safety accidents. Furthermore, when multiple resistors are used in parallel in a load, locating the faulty resistor after a failure is difficult, significantly complicating maintenance.

[0003] The inventors then developed an induction coil fitted around the lead-out terminals at the port of a metal outer tube. The induction coil is connected to an indicator light (this technology is not yet publicly disclosed). When a resistor malfunctions, the resistance wire burns out, no current flows through the lead-out terminals, the induction coil has no induced current, and the indicator light goes out. This allows for quick identification of whether the resistor is functioning correctly. When multiple parallel resistors malfunction, the faulty resistor can be quickly located and replaced. However, the inventors further discovered that while this innovation solves some current problems, it also has areas for improvement: after prolonged use, the indicator light is prone to damage, and may go out even when no fault is present, leading to accidental shutdowns for maintenance. Furthermore, power must be continuously supplied to measure the faulty resistance; this method cannot detect the faulty resistance after the equipment is powered off, causing inconvenience.

[0004] In addition, the inventors connected a PTC resistor to the resistance wire. When the resistance tube is used at normal temperature, the resistance value of the PTC resistor is within the normal range. When the resistor malfunctions (such as a short circuit) and the temperature becomes too high, the resistance value of the PTC resistor increases. The higher the temperature, the greater the resistance value, which increases the overall resistance of the resistance tube, reduces the power, and consequently reduces heat generation, thus avoiding malfunctions caused by overheating. However, the inventors further discovered that under high load operation, it is impossible to detect the resistor temperature in time. If the temperature exceeds the maximum tolerance value of the PTC, overheating and subsequent malfunctions are still unavoidable. Summary of the Invention

[0005] To address the aforementioned technical problems in the existing technology, the present invention provides a load resistor tube that is resistant to overheating and easy to identify faults.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A load resistor tube that is protected against overheating and facilitates fault identification is provided, comprising a metal outer tube and a resistance wire inserted inside the metal outer tube. The metal outer tube is filled with insulating powder, thereby separating the resistance wire from the inner wall of the metal outer tube. The tube is characterized by having a PTC resistor and a lead-out terminal at its end. One end of the PTC resistor is connected to the resistance wire, and the other end is connected to the lead-out terminal, which extends out of the metal outer tube. The PTC resistor is insulated from the inner wall of the metal outer tube. An induction coil, fitted around the lead-out terminal, is located at the port of the metal outer tube, and an indicator light is connected to the induction coil.

[0008] The PTC resistor is surrounded by an annular expansion body. The corresponding segment of the expansion body in the metal outer tube is provided with a deformation part, so that the expansion body expands and pushes outward to form a bulge after being heated to a preset temperature. The expansion body and the deformation part are insulated from each other.

[0009] Specifically, the deformed part is a thin-walled section with reduced thickness, or a soft section made of soft material.

[0010] Specifically, limit rings are provided on the outer sides of the PTC resistor near both ends. The limit rings limit the expansion body in the axial direction of the outer metal tube to guide the expansion body to expand radially.

[0011] Specifically, the expansion body is a metal body that expands when heated; or the expansion body includes an elastic bladder and a heated gas located within the elastic bladder.

[0012] Specifically, the deformed part is curved.

[0013] Specifically, the insulating powder is magnesium oxide powder.

[0014] Specifically, the port of the metal outer tube is equipped with a light-transmitting insulating post, and the induction coil and indicator light are wrapped inside the insulating post, which blocks the port of the metal outer tube.

[0015] Specifically, the insulating pillars are made of hot-melt epoxy resin that has been cooled and molded.

[0016] Specifically, the segments of the leads located inside the metal outer tube are also surrounded by the insulating powder, or surrounded by epoxy resin.

[0017] Specifically, the resistance wire is arranged in a spiral or wavy pattern inside the outer metal tube.

[0018] The beneficial effects of this invention are:

[0019] The present invention provides a load resistor tube that is resistant to overheating and easy to identify faults, compared with the prior art:

[0020] 1. When the resistor tube is used at normal temperature, the resistance value of the PTC resistor is within the normal range. When the resistor malfunctions (such as a short circuit) and the temperature becomes too high, the resistance value of the PTC resistor increases. The higher the temperature, the greater the resistance value, which increases the overall resistance value of the resistor tube, reduces the power, and consequently reduces the heat generation, thus avoiding failures caused by excessive temperature.

[0021] 2. When the resistor is working normally, current flows through the leads, and the external induction coil generates an induced current through electromagnetic induction, which lights up the indicator light. When the resistor malfunctions, the resistance wire burns out, no current flows through the leads, the induction coil has no induced current, and the indicator light goes out. This allows for quick determination of whether the resistor is working properly. In case of a fault, the location of the faulty resistor can be quickly determined and replaced.

[0022] 3. An annular expansion body is fitted around the outside of the PTC resistor. When the expansion body is heated to the preset temperature, it expands and pushes outward to form a bulge. Even if the indicator light is damaged or the load has just been de-energized, the resistor temperature can be indirectly detected by visual observation or visual inspection to check for bulges or their size. If the bulge is too large when the load is under high power conditions, the power can be cut off in time to avoid overload. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a load resistor tube that is protected against overheating and is easy to identify faults, as shown in the embodiment.

[0024] Figure 2 for Figure 1 A magnified view of a portion of the image.

[0025] Figure 3 for Figure 1 A schematic diagram of a structure with an added limiting ring.

[0026] Figure 4 for Figure 2 A schematic diagram showing the deformation part being changed to a curved shape.

[0027] Figure label:

[0028] 1. Metal outer tube, 11. Deformation part, 2. Resistance wire, 3. Insulating powder, 4. PTC resistor, 5. Lead-out terminal, 6. Induction coil, 7. Insulating column, 8. Expansion body, 9. Limiting ring, 10. Detailed Implementation

[0029] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0030] This embodiment provides a load resistor that is protected against overheating and allows for easy fault identification, such as... Figures 1 to 4As shown, the device includes a metal outer tube 1 and a resistance wire 2 inserted inside the metal outer tube 1. The metal outer tube 1 is an aluminum tube, and it is filled with insulating powder 3, which is magnesium oxide powder, thus separating the resistance wire 2 from the inner wall of the metal outer tube 1. A PTC resistor 4 and a lead-out terminal 5 are located at the end of the metal outer tube 1. One end of the PTC resistor 4 is connected to the resistance wire 2, and the other end is connected to the lead-out terminal 5, which extends out of the metal outer tube 1. An insulating layer is provided on the outside of the PTC resistor 4 to insulate it from the inner wall of the metal outer tube 1. An induction coil 6 is fitted around the lead-out terminal 5 at the port of the metal outer tube 1, and an indicator light 7 is connected to the induction coil 6. The ends of the resistor and the lead-out terminal 5 are fixed to the PTC resistor 4 by welding.

[0031] Specifically, the port of the metal outer tube 1 is provided with a light-transmitting insulating post 8, which is made of hot-melt epoxy resin and cooled and molded. The induction coil 6 and the indicator light 7 are wrapped inside the insulating post 8, and the insulating post 8 blocks the port of the metal outer tube 1. The insulating post 8 is flush with the outer wall of the metal outer tube 1.

[0032] In this embodiment, the segment of the lead-out terminal 5 located inside the metal outer tube 1 is also surrounded by the insulating powder 3, or surrounded by epoxy resin.

[0033] In practice, the resistance wire 2 is arranged spirally or in a wavy shape inside the metal outer tube 1.

[0034] In this embodiment, the outer metal tube 1 is a straight tube, but it can actually be replaced with a U-shaped tube.

[0035] When the resistor tube is used at normal temperature, the resistance of PTC resistor 4 is within the normal range. When the resistor malfunctions (such as a short circuit) and the temperature becomes too high, the resistance of PTC resistor 4 increases. The higher the temperature, the greater the resistance, which increases the overall resistance of the resistor tube, reduces the power, and consequently reduces the heat generation, thus avoiding accidents caused by excessive temperature.

[0036] When the resistor is working normally, alternating current flows through terminal 5. The external induction coil 6 generates an induced current through electromagnetic induction, illuminating indicator light 7. The principle is that when alternating current flows through the terminal, a changing magnetic field is generated in the adjacent closed induction coil 6, thus producing current. When the resistor malfunctions, the resistance wire 2 burns out, no current flows through terminal 5, and therefore no induced current is generated in induction coil 6, turning off indicator light 7. This allows for quick identification of whether the resistor is functioning correctly, and in case of a fault, the location of the faulty resistor can be quickly determined for replacement.

[0037] The PTC resistor 4 is surrounded by an annular expansion body 9. The segment of the metal outer tube 1 corresponding to the expansion body 9 is provided with a deformation part 11 so that the expansion body 9 expands outward and pushes the deformation part to form a bulge after being heated to a preset temperature. The expansion body 9 and the deformation part 11 are insulated from each other.

[0038] In this embodiment, the deformable part 11 is a thin-walled section with reduced thickness. In practice, it can be replaced with a soft section made of soft material so that it can be squeezed and deformed outwards to arch up.

[0039] In this embodiment, limit rings 10 are respectively provided on the outer side of the PTC resistor 4 near both ends. The limit rings 10 limit the expansion body in the axial direction of the metal outer tube 1 to guide the expansion body 9 to expand radially.

[0040] In this embodiment, the expansion body 9 is a thermally expanding metal body, such as mercury, gold, silver, copper, or aluminum, preferably an aluminum ring. By setting the deformation portion 11 to a preset thickness, the metal body will thermally deform outward after being heated to a certain temperature. Alternatively, the expansion body 9 may include a high-temperature resistant elastic bladder and a thermally expanding gas located within the elastic bladder. The heat generated by the PTC resistor heats the expanding gas through the elastic bladder, causing the elastic bladder to expand and support the deformation portion. The thickness of the elastic bladder and the density of the thermally expanding gas can be determined through a limited number of tests, ensuring that the elastic bladder deforms only at a certain temperature and does not deform within the temperature range. When the PTC resistor 4 overheats severely, the expansion body 9, which is fitted onto the outer wall, expands due to heat, squeezing a portion of the outer wall of the metal outer tube 1 to cause it to bulge. During equipment shutdown and inspection, it is possible to quickly identify which resistor tube is severely overheated, thereby quickly locating the problematic resistor tube.

[0041] The manufacturing method of the above resistor tube includes the following steps:

[0042] 1. Spray metal electrodes onto both sides of the cylindrical PTC resistor 4;

[0043] 2. Solder the lead terminal 5 to one end of the PTC resistor 4 and the resistance wire 2 to the other end; install a thermal expansion element on the outside of the PTC resistor 4;

[0044] 3. Insert the welded resistance wire 2 and PTC resistor 4 into the metal outer tube 1, then fill it with magnesium oxide powder, and finally compact the magnesium oxide powder by shrinking the tube.

[0045] 4. Install an LED indicator 7 on the induction coil 6;

[0046] 5. The induction coil 6 with indicator light 7 is encapsulated and fixed with transparent epoxy resin to form an insulating column 8;

[0047] 6. Install the insulating post 8 outside the lead-out terminals 5 at both ends of the metal outer tube 1, replacing the original ceramic end cap of the resistor.

[0048] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0049] All standard parts used in this invention can be purchased from the market, and irregular parts can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art, and the circuit connection adopts conventional connection methods in the prior art, which will not be described in detail here.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A load resistor tube that is resistant to overheating and facilitates fault identification, comprising a metal outer tube and a resistance wire inserted within the metal outer tube, wherein the metal outer tube is filled with insulating powder to separate the resistance wire from the inner wall of the metal outer tube, characterized in that: The end of the metal outer tube is equipped with a PTC resistor and a lead-out terminal. One end of the PTC resistor is connected to a resistance wire, and the other end of the PTC resistor is connected to the lead-out terminal, which extends out of the metal outer tube. The PTC resistor is insulated from the inner wall of the metal outer tube. An induction coil is installed at the port of the metal outer tube, which is fitted around the lead-out terminal. An indicator light is connected to the induction coil. The PTC resistor is surrounded by an annular expansion body. The corresponding segment of the expansion body in the metal outer tube is provided with a deformation part, so that the expansion body expands outward and pushes the deformation part to form a bulge after being heated to a preset temperature. The expansion body and the deformation part are insulated from each other.

2. A load resistor tube that is protected against overheating and easily identifiable for faults according to claim 1, characterized in that: The deformed section is either a thin-walled segment with reduced thickness or a soft segment made of soft material.

3. A load resistor tube that is protected against overheating and easily identifiable for faults according to claim 1, characterized in that: Limiting rings are provided on the outer side of the PTC resistor near both ends. The limiting rings limit the expansion body in the axial direction of the outer metal tube to guide the expansion body to expand radially.

4. A load resistor tube that is protected against overheating and easily identifiable for faults according to claim 1, characterized in that: The expansion body is a metal body that expands when heated; or the expansion body includes an elastic bladder and a heated gas located within the elastic bladder.

5. A load resistor tube that is protected against overheating and easily identifiable for faults according to claim 1, characterized in that: The deformed part is curved.

6. A load resistor tube that is protected against overheating and easily identifiable for faults according to claim 1, characterized in that: The insulating powder is magnesium oxide powder.

7. A load resistor tube that is protected against overheating and easily identifies faults according to claim 1, characterized in that: The port of the metal outer tube is equipped with a light-transmitting insulating post, and the induction coil and indicator light are wrapped inside the insulating post, which blocks the port of the metal outer tube.

8. A load resistor tube that is protected against overheating and easily identifiable for faults according to claim 7, characterized in that: The insulating pillars are formed by cooling hot-melt epoxy resin.

9. A load resistor tube that is protected against overheating and easily identifiable for faults according to claim 1, characterized in that: The segments of the leads located inside the metal outer tube are also surrounded by the insulating powder, or surrounded by epoxy resin.

10. A load resistor tube that is protected against overheating and easily identifiable for faults according to claim 1, characterized in that: The resistance wire is arranged in a spiral or wavy pattern inside a metal outer tube.

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