Pipe-insertable heating wire

Abstract

To provide a pipe-insertable heating wire, and more particularly, a pipe-insertable heating wire that is inserted into the inside of a pipe to prevent freezing of a water supply pipe or a drainage pipe.SOLUTION: A pipe-insertable heating wire comprises: a pair of conductors having a wire shape made of an alloy mixed with nickel and chromium-iron, or an alloy mixed with nickel and copper, arranged side by side in the longitudinal direction while maintaining a gap from each other, and having a power consumption of 8 to 12 W / m per 1 m in a serial heating method to generate heat at less than 60°C based on an external temperature of 25±2°C; an inner jacket covering the outer side of each of the conductors; a ground cable having tensile strength and arranged side by side in the longitudinal direction while maintaining a gap from the conductors; and an outer jacket that is covered on the outside while maintaining the gap between the conductors and the ground cable.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a pipe insertion type heating wire, and more particularly to a pipe insertion type heating wire that is inserted inside a water supply pipe or a drainage pipe to prevent the pipe from freezing. [Background technology]

[0002] In winter, fluid flowing inside water supply or drainage pipes, such as fire extinguishing pipes, freezes, and the volume increases when it freezes, causing the pipes to be unable to withstand the increased volume of fluid and often to break.

[0003] In order to prevent such freeze damage to the pipeline, many freeze damage prevention devices have been proposed that generate heat by inserting a heating wire directly into the pipeline to prevent the fluid from freezing.

[0004] For example, in Korean Patent Publication No. 10-2015-0018740 (Heat Wire System for Preventing Freezing Damage), as shown in Figure 1, a PTC (Positive Temperature Coefficient) heating cable 13 is installed on the outer surface of a pipe 30 either in close contact with the pipe in the longitudinal direction or wound in a spiral shape, and is finished by being covered with a heat insulating material 40 on the outside.

[0005] Therefore, the PTC heating cable 13 generates heat due to the supplied power, and the temperature of the fluid inside the piping 30 is raised above the freezing temperature, thereby preventing freezing.

[0006] Such PTC heating cables 13 generally use self-regulating heating cables, and the method of generating heat using such self-regulating heating cables is not a metal heating wire but a plastic semiconductor containing carbon, and is a self-regulating heating method that utilizes the characteristics of PTC (Positive Temperature Coefficient).

[0007] In other words, the conductive carbon particles are configured as an infinite parallel circuit, and the amount of heat generated automatically changes in proportion to the ambient temperature. During initial operation, until the proper balance with the external temperature is maintained, the device operates while consuming 2 to 2.5 times more power (32 to 35 W / m) than the power required to maintain the proper temperature (16 W / m). Once the proper balance is maintained, the device operates constantly at 16 W / m.

[0008] This results in a very large power consumption at the beginning of operation, and because it is self-regulating, unnecessary power consumption occurs. In addition, since a high temperature is maintained due to the high power consumption at the beginning, the polymer outer shell that protects the outside of the heating element easily deteriorates, resulting in a very short service life.

[0009] Furthermore, when repairing or replacing the PTC heating cable 13, all finishing materials, including the outer insulation 40, must be removed and then reinstalled, which is a major disadvantage from a maintenance perspective. In addition, since this method indirectly heats the pipe, it also has the disadvantage of reducing thermal efficiency accordingly.

[0010] In particular, since the device is installed outside the piping and is wrapped in the heat insulating material 40, it has the problem of being extremely vulnerable to fire.

[0011] Furthermore, because they are very expensive, they are often not installed on the entire pipe, but only in localized areas where freezing is likely to occur, so they are not very effective in preventing freezing damage to pipes installed over long distances.

[0012] As described above, due to the many problems that arise when installing a PTC heating cable outside a pipe, a method of inserting a heating wire inside the pipe is used. For example, in Korean Patent Publication No. 10-2014-0052515 (Pipe Freeze Damage Prevention Device), as shown in FIG. 2, a heating wire 130 is inserted and installed inside the length of a pipe 102 through which a fluid flows, and both ends of the heating wire 130 are pulled out to the outside of the pipe 102 through a connecting valve 120, and power is supplied through the pulled out parts to prevent freezing and freeze damage.

[0013] However, when such a heating wire 130 is used, if a PTC heating cable is used, it is very expensive, so installation costs are high, and since the tensile strength is very low, when it is installed inside a long-distance pipe, it is prone to damage such as poor cutting, and frequent maintenance is required. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Korean Patent Publication No. 10-2015-0018740 (Heat Wire System to Prevent Freezing Damage) [Patent Document 2] Korean Patent Publication No. 10-2014-0052515 (Pipe freeze damage prevention device) Summary of the Invention [Problem to be solved by the invention]

[0015] In order to solve these problems, the present invention aims to provide a conduit insertion type heating wire that can be inserted into a conduit to prevent ice formation by forming a primary coating of heat-resistant and chemical-resistant Teflon (registered trademark) on the outside of a conductor made of a nickel-chromium-iron alloy or a nickel-copper alloy along the length, applying a wire to increase grounding and tensile strength, and forming an outer jacket with a coating material that is heat-resistant PVC or a mixture of heat-resistant PVC and silicone. [Means for solving the problem]

[0016] In order to achieve the above object, the pipe insertion type heating wire of the present invention comprises: A pair of conductors in the form of wires made of a nickel-chromium-iron alloy or a nickel-copper alloy, arranged in parallel in the length direction while maintaining a gap between them, with a power consumption of 8 to 12 W / m per meter in a serial heating method, and generating heat at less than 60°C based on an ambient temperature of 25±2°C; an inner jacket covering the outside of each of the conductors; a grounding cable having a tensile force and arranged longitudinally alongside the conductor while maintaining a spacing therebetween; and an outer jacket that is placed over the conductor and the grounding cable while maintaining a distance between the conductor and the grounding cable. [Effects of the Invention]

[0017] According to the present invention configured as above, a heating wire including a conductor made of a nickel-chromium-iron alloy or a nickel-copper alloy is inserted and laid inside the conduit along the length using a serial heating method, which has the advantages of being able to be used semi-permanently while having very low power consumption of about 8 to 12 W / m, being heat resistant, and having very low risk of fire. In addition, the grounding cable (grounding wire) has a very high tensile strength but is inexpensive, allowing for stable installation inside long-distance conduits. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram showing the structure of a conventional freeze damage prevention hot wire system. [Figure 2] FIG. 1 is a diagram showing a state in which a heating wire is inserted and laid inside a pipe according to the prior art. [Figure 3] 1 is a diagram showing the structure of a pipe insertion type heating wire according to the present invention; [Figure 4] 1 is a cross-sectional structural view of the present invention. [Figure 5] 10 is a photograph showing the heating temperature of a heating wire when the conductor length is 10 m. [Figure 6] 10 is a photograph showing the heating temperature of a heating wire when the conductor length is 30 m. DETAILED DESCRIPTION OF THE INVENTION

[0019] Accordingly, the scope of the invention should be defined not by the illustrated embodiments, but by the claims that follow.

[0020] The above-mentioned objects, features and advantages will be described in detail below with reference to the accompanying drawings, so that a person having ordinary skill in the art to which the present invention pertains can easily implement the technical idea of ​​the present invention.

[0021] In describing the present invention, if it is determined that a detailed description of known techniques related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0023] However, the embodiments of the present invention exemplified below can be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below in detail.

[0024] The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

[0025] FIG. 3 shows the structure of a conduit-insertion type heating wire according to the present invention, which is broadly composed of a pair of conductors 131, 131', inner jackets 132, 132', a pair of grounding cables 133, 133', and an outer jacket .

[0026] The pair of conductors 131, 131' generate heat due to their resistance components, and are formed in the form of wires made of an alloy of nickel and chromium-iron or an alloy of nickel and copper along the length of the conductors 131, 131', and the pair of conductors 131, 131' are arranged side by side with a gap in the longitudinal direction.

[0027] Here, the length of the conductors 131, 131' may be the length of the section where water is heated inside the water supply pipeline or drainage pipeline to prevent the water supply pipeline or drainage pipeline from freezing, for example, 10 m, 30 m, 50 m, 60 m, 80 m, etc.

[0028] The power consumption per meter of such conductors 131, 131' is determined by the ratio of nickel and chromium-iron or nickel and copper along the length, but the power consumption of 8 to 12 W / m in the serial heating method allows for constant heat generation, so unnecessary power consumption does not occur.

[0029] That is, regardless of changes in the outside air temperature, heat is generated with a constant power consumption of 8W / m to 12W / m during initial operation and regular operation.

[0030] The inner jackets 132, 132' are formed by coating or extruding Teflon on the outside of the conductors 131, 131'. Teflon is heat-resistant, chemical-resistant, and flexible, and insulates the conductors 131, 131'. Since it has heat resistance of 105°C or more, it does not break down at 105°C, the maximum instantaneous allowable temperature of the heating wire, and stable insulation is possible.

[0031] A pair of ground cables 133, 133' are arranged in the longitudinal direction with a gap between them, parallel to the pair of conductors 131, 131'. These ground cables 133, 133' are formed by arranging various strands of tin-plated copper wires side by side to form an assembly, and these ground cables 133, 133' not only function as grounding cables, but also act as tension cables since they have tensile force.

[0032] In particular, inside a vertically installed pipe, the heating wire must be laid as close to the center as possible, so when laid over a long distance inside a pipe of several tens of meters, the heating wire can be prevented from breaking due to the tensile force of the grounding cables 133, 133'.

[0033] Furthermore, when a heating wire is laid long distance inside a horizontally placed pipe, the heating wire hangs down and may melt or deform the pipe if it comes into contact with the inner surface of the PVC pipe. However, by applying a tensile force using the grounding cables 133, 133', this problem can be solved by preventing the heating wire from coming into contact with the inner surface of the pipe.

[0034] The outer jacket 134 is made of heat-resistant PVC and is extruded together with the conductors 131, 131' and ground cables 133, 133' on which the inner jacket 132 is formed, thereby maintaining the spacing between the conductors 131, 131' and the ground cables 133, 133' and covering the outside of them to protect them.

[0035] To prevent such an outer jacket 134 from hardening easily due to heat generation and to make it flexible so that it can be easily installed inside curved piping, silicone and heat-resistant PVC can be mixed and extruded.

[0036] Furthermore, double insulation is provided by the inner jackets 132, 132' and the outer jacket 134, so that the cable can be safely installed inside the pipe.

[0037] In addition, by adjusting the content of nickel and chromium-iron or nickel and copper that make up the conductors 131 and 131', the conductors have a heat output of 8 to 12 W / m, and generate heat at less than 60°C based on an ambient temperature of 25±2°C, so they do not cause damage such as melting or deforming the PVC pipes.In addition, by adjusting the content of nickel and chromium-iron or nickel and copper, the heat output can be adjusted, making it possible to customize production to suit the installation conditions.

[0038] Table 1 below shows the nickel and chromium-iron or nickel and copper content, the number of conductor strands that make up one conductor, and the resistance value of each conductor strand when the length of each conductor 131, 131' is 10 m, 30 m, 50 m, 60 m, or 80 m, so that the pair of conductors 131, 131' has a heat value of 8 to 12 W / m and the heating wire generates heat at less than 60°C based on an outside air temperature of 25±2°C.

[0039] [Table 1]

[0040] Here, ferrochromium is an alloy of chromium and iron, and contains 30 to 50% by weight of iron.

[0041] Furthermore, the number of strands of a conductor is the number of strands that make up one conductor 131 or 131', 1P is the resistance value of one conductor 131 or 131', and 2P is the sum of the resistance values ​​of the pair of conductors 131, 131'.

[0042] The ranges of the component ratio, number of strands, and resistance value of a conductor with a length of 10 m include (cover) the component ratio, number of strands, and resistance value of a conductor with a length of 5 to 19 m. The component ratio, number of strands, and resistance value ranges of a 30 m conductor include lengths of 20 to 39 m, a 50 m conductor include lengths of 40 to 55 m, a 60 m conductor include lengths of 56 to 75 m, and an 80 m conductor include lengths of 76 to 80 m or more.

[0043] That is, by adjusting the component ratio of the conductor and the number of strands of the conductor within the above ranges, it is possible to obtain an appropriate resistance value within the above-mentioned range of conductor length.

[0044] In addition, when the diameter of the pipe is large or in extreme regions where the outside air temperature is very low, the heat generation must be increased to approximately 14 to 16 W / m. In such cases, however, the PVC outer jacket 134 may deteriorate due to the heat generation temperature, so the outer jacket 134 may be made of Teflon (registered trademark) instead of PVC.

[0045] The heat resistance temperature of Teflon (registered trademark) is 300°C or higher, so even if the amount of heat generated is increased, deterioration does not occur.

[0046] FIG. 5 shows that when the length of the conductor 131 is 10 m and the outside air temperature is 24.9°C, the heating temperature of the heating wire in which the conductor 131 is covered with the inner jacket 132 and the outer jacket 134 is 55°C.

[0047] This satisfies the heating condition of the heating wire of the present invention, that is, heat generation at an outside air temperature of 25±2°C or less than 60°C.

[0048] Furthermore, FIG. 6 shows that when the length of the conductor 131 is 30 m and the outside air temperature is 26.1°C, the heating temperature of the heating wire in which the conductor 131 is covered with the inner jacket 132 and the outer jacket 134 is 57.6°C, which also satisfies the heating condition of the heating wire of the present invention, that is, to generate heat at less than 60°C based on an outside air temperature of 25±2°C.

[0049] While the specific parts of the present invention have been described in detail above, it will be apparent to those skilled in the art that these specific techniques are merely preferred embodiments and do not limit the scope of the present invention.

[0050] Therefore, the true scope of the invention is to be defined by the appended claims and their equivalents.

[0051] In this application, the Teflon (registered trademark) used to form the inner jackets 132, 132' is a perfluoro-based fluororesin, particularly a perfluoro-alkyl or perfluoro-alkoxy fluororesin. More specifically, it includes polytetrafluoroethylene [PTFE] (tetrafluoroethylene resin), perfluoroalkoxyalkane [PFA] (tetrafluoroethylene-perfluoroalkylvinylether copolymer resin), perfluoroethylenepropene copolymer [FEP] (tetrafluoroethylene-hexafluoropropylene copolymer resin), etc. (www.jfia.gr.jp / kinds.html)

[0052] In addition, the heat-resistant PVC used to form the outer jacket 134 in this application is specifically CPVC (chlorinated polyvinyl chloride), with a chlorine content increased from 57% of regular PVC to 60-70%, resulting in a heat-resistant temperature of approximately 110°C, a 10-40°C improvement. (https: / / www.durastream.com / ja / product-comparison / pvc / )

[0053] Heat-resistant PVC can be blended with a heat-resistant, non-migratory plasticizer such as a polyester-based (especially adipic acid-based or phthalic acid-based; for example, number-average molecular weight 2000 to 4000) plasticizer (see, for example, https: / / www.dic-global.com / ja / products / modifier / pvc_plasticizer / ). When using a polymer blend of heat-resistant PVC and silicone, for example, silicone rubber is used in an amount of 1 to 30% by weight. The content can be 1 to 20% by weight or 1 to 10% by weight. [Explanation of symbols]

[0054] 130 Heating Wire 131, 131' conductor 132, 132' inner jacket 133, 133' Ground Cable 134 outer jacket

Claims

1. A pipe-insertion type heating wire is inserted and laid lengthwise inside a pipe through which a fluid flows, and both ends of the wire are drawn out to the outside of the pipe and supplied with power for generating heat, a pair of conductors in the form of wires made of an alloy of 73 to 83 weight percent nickel and 17 to 27 weight percent chromium-iron, arranged in parallel in the length direction while maintaining a gap between them, having a power consumption of 8 to 12 W / m per meter in a serial heating method, and generating heat at less than 60°C based on an ambient temperature of 25±2°C; an inner jacket covering the outside of each of the conductors; a grounding cable having a tensile force and arranged longitudinally alongside the conductor while maintaining a spacing therebetween; and an outer jacket that is placed over the conductor from the outside while maintaining a distance between the conductor and the grounding cable.

2. A pipe-insertion type heating wire is inserted and laid lengthwise inside a pipe through which a fluid flows, and both ends of the wire are drawn out to the outside of the pipe and supplied with power for generating heat, a pair of conductors in the form of wires made of an alloy of 15 to 30% by weight of nickel and 70 to 85% by weight of copper, arranged in parallel in the length direction while maintaining a gap between them, having a power consumption of 8 to 12 W / m per meter in a serial heating method, and generating heat at less than 60°C based on an ambient temperature of 25±2°C; an inner jacket covering the outside of each of the conductors; a grounding cable having a tensile force and arranged longitudinally alongside the conductor while maintaining a spacing therebetween; and an outer jacket that covers the outside of the conductor while maintaining a gap between the conductor and the grounding cable.

3. A pipe-insertion type heating wire is inserted and laid lengthwise inside a pipe through which a fluid flows, and both ends of the wire are drawn out to the outside of the pipe and supplied with power for generating heat, a pair of conductors in the form of wires made of an alloy of 3 to 15% by weight of nickel and 85 to 97% by weight of copper, arranged in parallel in the length direction while maintaining a gap between them, having a power consumption of 8 to 12 W / m per meter in a serial heating method, and generating heat at less than 60°C based on an ambient temperature of 25±2°C; an inner jacket disposed over the outside of each of the conductors; a grounding cable having a tensile force and arranged longitudinally alongside the conductor while maintaining a spacing therebetween; and an outer jacket that covers the outside of the conductor while maintaining a gap between the conductor and the grounding cable.

4. A pipe-insertion type heating wire is inserted and laid lengthwise inside a pipe through which a fluid flows, and both ends of the wire are drawn out to the outside of the pipe and supplied with power for generating heat, a pair of conductors in the form of wires made of an alloy of 5 to 15% by weight of nickel and 85 to 95% by weight of copper, arranged in parallel in the length direction while maintaining a gap between them, having a power consumption of 8 to 12 W / m per meter in a serial heating method, and generating heat at less than 60°C based on an ambient temperature of 25±2°C; an inner jacket covering the outside of each of the conductors; a grounding cable having a tensile force and arranged longitudinally alongside the conductor while maintaining a spacing therebetween; and an outer jacket that covers the outside of the conductor while maintaining a gap between the conductor and the grounding cable.

5. A pipe-insertion type heating wire is inserted and laid lengthwise inside a pipe through which a fluid flows, and both ends of the wire are drawn out to the outside of the pipe and supplied with power for generating heat, a pair of conductors in the form of wires made of an alloy of 1 to 7% by weight of nickel and 93 to 99% by weight of copper, arranged in parallel in the length direction while maintaining a gap between them, having a power consumption of 8 to 12 W / m per meter in a serial heating method, and generating heat at less than 60°C based on an ambient temperature of 25±2°C; an inner jacket covering the outside of each of the conductors; a grounding cable having a tensile force and arranged longitudinally alongside the conductor while maintaining a spacing therebetween; and an outer jacket that is placed over the conductor from the outside while maintaining a distance between the conductor and the grounding cable.

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