Heater, electrostatic precipitator, and method for manufacturing heater

Abstract

To provide a heater which can reliably inhibit or prevent inflow of air into a pipe, in which a heating wire is disposed, and to provide an electric dust collector and a manufacturing method of the heater.SOLUTION: A heater includes: a heating wire 2; a pipe 3 in which the heating wire 2 is disposed; a housing part 4 which is installed at an end of the pipe 3 so as to enclose an outer periphery part of the pipe 3 and filled with an epoxy resin 15; and a terminal part 5 provided at the opposite side of the pipe 3 side in the housing part 4 and connected with the heating wire 2 which may be connected with an external power source.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a heater, an electrostatic precipitator, and a method for manufacturing the heater. [Background technology]

[0002] An electrostatic precipitator is equipped with a dust collecting electrode and a discharge electrode, and a corona discharge is generated by applying a high DC voltage between the collecting electrode and the discharge electrode. The corona discharge charges dust particles contained in the gas flowing through the electrostatic precipitator, and the charged dust particles are collected on the collecting electrode by the action of Coulomb force acting on the dust particles in the electric field between the collecting electrode and the discharge electrode.

[0003] Electrostatic precipitators are classified into dry electrostatic precipitators and wet electrostatic precipitators. Dry electrostatic precipitators knock off dust collected on the dust collecting electrodes by impact force such as hammering, while wet electrostatic precipitators wash off the dust collected on the dust collecting electrodes using a cleaning liquid such as water or collection liquid. Wet electrostatic precipitators have the advantage that the surface of the dust collecting electrodes is wetted with the cleaning liquid, which prevents dust from re-scattering and makes it difficult for highly hygroscopic dust to adhere to the dust collecting electrodes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 55-44435 Summary of the Invention [Problem to be solved by the invention]

[0005] The discharge electrode is connected to an external high-voltage power source via an electric conductor. The electric conductor is, for example, a metal part, and is insulated from the structure of the electrostatic precipitator by the insulator and is supported by the insulator. In a wet-type electrostatic precipitator, the insulator is placed in a protective tube (insulator cover) installed inside the insulator chamber. The protective tube is heated by an insulator heater installed on the outer surface side, thereby drying the insulator inside. Drying the insulator prevents damage to the insulator due to creeping discharge caused by moisture condensation, etc.

[0006] If the humidity rises inside the insulator room where the insulator heater is installed due to a water leak or other reason, there is a risk that highly humid air will flow into the main body of the insulator heater from the terminals of the heater. The heater is filled with a heating wire and insulating filler, but if highly humid air flows in, it will reduce the insulation resistance of the heater, making it impossible to turn on the heater.

[0007] In order to prevent damage to the insulators, operating conditions are set such that application of voltage (charging) to the discharge electrode is permitted only when the temperature conditions of the protective tube are met. When this is the case, if the insulation resistance of the insulator heater decreases, the electric dust collector cannot be operated.

[0008] In addition, in a dry electrostatic precipitator, since the humidity is lower than in a wet electrostatic precipitator, a protective tube is not provided, but an insulator heater is installed around the insulator to keep the insulator dry. Also, in the case of a dry electrostatic precipitator, it is necessary to prevent high humidity air from entering the main body of the insulator heater.

[0009] The above-mentioned Patent Document 1 discloses an invention relating to a sealing method for a pipe heater. The end of the pipe is filled with a heat-resistant insulator such as silicon varnish, glass seal, silicon rubber, or epoxy resin. However, if the insulation shrinks or deforms in the longitudinal or radial direction of the pipe due to deterioration of the insulation, a gap without insulation is formed, and there is a risk that high-humidity air will flow into the inside of the pipe.

[0010] The present disclosure has been made in consideration of the above circumstances, and aims to provide a heater, an electric dust collector, and a method for manufacturing a heater that can reliably suppress or prevent the inflow of air into a pipe in which an electric heating wire is arranged. [Means for solving the problem]

[0011] In order to solve the above problems, the heater, the electrostatic precipitator, and the method for manufacturing the heater according to the present disclosure employ the following measures. That is, the heater according to the present disclosure comprises a heating wire, a pipe with the heating wire arranged inside, a housing portion installed at the end of the pipe so as to surround the outer periphery of the pipe and filled with a synthetic resin material, and a terminal portion provided on the opposite side of the housing portion from the pipe, connected to the heating wire and capable of being connected to an external power source.

[0012] The electric dust collector according to the present disclosure includes the above-mentioned heater, a discharge electrode constituting an electric dust collecting section, and an insulator supporting an electric conductor connected to the discharge electrode and having the heater installed along its outer circumferential surface.

[0013] A method of manufacturing a heater according to the present disclosure includes the steps of connecting a terminal portion to an end of a heating wire, placing the heating wire inside a pipe, installing a accommodating portion at the end of the pipe so as to surround the outer periphery of the pipe, filling the inside of the accommodating portion with a synthetic resin material, and providing the terminal portion on the side of the accommodating portion opposite the pipe. Effect of the Invention

[0014] According to the present disclosure, it is possible to reliably suppress or prevent the inflow of air into the inside of a pipe in which a heating wire is arranged. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view showing an insulator, a thermal insulation exterior plate, a protective tube, a thermal insulation material, and an insulator protection heater according to an embodiment of the present disclosure, with a portion cut away to show the inside. FIG. [Diagram 2] FIG. 1 is a plan view showing an insulator protection heater according to an embodiment of the present disclosure. [Diagram 3] 1 is a front view showing an insulator protection heater according to an embodiment of the present disclosure; [Figure 4] FIG. 2 is a side view showing an end portion of an insulator protection heater according to an embodiment of the present disclosure. [Diagram 5] FIG. 13 is a perspective view showing an insulator and an insulator protection heater according to a modified example of an embodiment of the present disclosure, partially cut away to show the inside. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, a heater for protecting an insulator according to an embodiment of the present disclosure will be described with reference to the drawings. An insulator protection heater 1 (hereinafter referred to as "heater 1") according to this embodiment is a device that heats the periphery of an insulator 20 of a wet electrostatic precipitator, as shown in FIG.

[0017] A wet electrostatic precipitator is equipped with a dust collecting electrode and a discharge electrode. A corona discharge occurs when a high DC voltage is applied between the collecting electrode and the discharge electrode. The corona discharge charges dust particles contained in the gas flowing through the electrostatic precipitator, and the charged dust particles are collected on the collecting electrode by the action of Coulomb force acting on the dust particles in the electric field between the collecting electrode and the discharge electrode.

[0018] The wet electrostatic precipitator includes a cleaning unit that uses a cleaning liquid such as water or a collecting liquid to wash away dust collected on the dust collecting electrode. The cleaning unit supplies the cleaning liquid to the dust collecting electrode during cleaning.

[0019] The insulator 20 insulates an electric conductor 24 connected to the discharge electrode from other structures of the wet electrostatic precipitator, and supports the electric conductor 24. The discharge electrode is connected to an external high-voltage power supply via the electric conductor 24.

[0020] In a wet electrostatic precipitator, if a non-conformity such as a hole is created in the insulator chamber occurs, high humidity air may flow from the internal space 30 of the electrostatic precipitator into the area around the insulator 20, and if moisture condenses on the surface of the insulator 20, a creeping discharge may occur, which may damage the insulator 20. To prevent damage to the insulator 20, the wet electrostatic precipitator is provided with a heat-insulating exterior plate 12, a protective tube 13, a heat-insulating material 14, and a heater 1 that protect the insulator 20.

[0021] 1, the insulator 20 is provided on its outer periphery with a heat-insulating exterior plate 12, a protective tube 13, a heat-insulating material 14, a heater 1, etc. The insulator 20, the heat-insulating exterior plate 12, the protective tube 13, the heat-insulating material 14, and the heater 1 are installed on a ceiling material 32 provided inside the wet electrostatic precipitator, for example.

[0022] The heat-insulating exterior plate 12 has, for example, a cylindrical shape, and houses the protective tube 13 inside the cylinder. A heat-insulating material 14 is provided between the inner surface of the heat-insulating exterior plate 12 and the outer surface of the protective tube 13. The heat-insulating material 14 is provided along the outer circumferential surface of the protective tube 13 so as to surround the outer circumferential surface of the protective tube 13.

[0023] The protective cylinder 13 is an example of a cylinder portion, and has, for example, a cylindrical shape, and is housed inside the heat-insulating exterior plate 12. The protective cylinder 13 houses an insulator 20 inside. The heater 1 is installed on the outer circumferential surface of the protective cylinder 13.

[0024] The insulator 20 is, for example, cylindrical and has a truncated cone shape. An electric conductor 24 connected to a discharge electrode is suspended inside the insulator 20 in parallel to the axial direction of the insulator 20. The electric conductor 24 is supported by the insulator 20 via a support 22 placed on the upper part of the insulator 20.

[0025] The heater 1 includes a pipe 3 with a built-in heating wire 2, for example, as shown in Fig. 4, and is provided along the outer circumferential surface of a protective tube 13 that is placed inside a cylinder of a thermal insulation exterior plate 12. The inside of the protective tube 13 is heated by the heater 1, so that the insulator 20 placed inside is brought into a dry state. By drying the insulator 20, damage to the insulator 20 due to creeping discharge caused by moisture condensation on the surface of the insulator 20 is prevented.

[0026] As shown in FIGS. 2 to 4, the heater 1 includes, for example, a heating wire 2 (see FIG. 4), a pipe 3, a housing portion 4, a terminal portion 5, and the like.

[0027] The heating wire 2 is, for example, a nichrome wire in a coil shape, and is disposed inside the pipe 3 along the longitudinal direction of the pipe 3. The heating wire 2 generates heat when electricity is applied thereto.

[0028] The pipe 3 is a hollow member, for example, with a circular cross section cut perpendicular to its axis. The pipe 3 is made of, for example, steel. The pipe 3 has a heating wire 2 and an insulating material (not shown) installed inside. The heating wire 2 is protected by the pipe 3. The insulating material is, for example, magnesium oxide, and is a heat-resistant material that insulates the electricity flowing through the heating wire 2 and transfers the heat generated by the heating wire 2 to the pipe 3.

[0029] The pipes 3 are arranged along the circumferential direction on the outer circumferential surface of the protective tube 13. Terminal parts 5 are provided on both ends of the pipes 3. One pipe 3 is provided so as to occupy approximately half of the outer circumferential surface of the protective tube 13, and the two pipes 3 are provided so as to be symmetrical when the protective tube 13 is viewed from above (when viewed in plan).

[0030] The pipe 3 has a first bent portion 3a in the middle and a second bent portion 3b in the vicinity of the storage portion 4 and the terminal portion 5. At the first bent portion 3a, the pipe 3 is bent to have a semicircular shape. At the second bent portion 3b, the pipe 3 arranged along the circumferential direction of the outer circumferential surface of the protective tube 13 is bent to extend parallel to the radial direction of the protective tube 13. By bending the pipe 3 into the above-mentioned shape, the terminal portions 5 at both ends are located close to each other.

[0031] A tightening band (not shown) is provided on the outside of the pipe 3 opposite the protective tube 13 side along the circumferential direction of the protective tube 13. The pipe 3 is fixed to the protective tube 13 by clamping the pipe 3 between the tightening band and the outer circumferential surface of the protective tube 13.

[0032] An accommodation section 4 is provided at the end of the pipe 3. The accommodation section 4 is provided at the end of the pipe 3 so as to surround the outer periphery of the pipe 3. As shown in Fig. 4, the accommodation section 4 has, for example, a hollow tubular section 6, a first end plate 7 provided at the end of the tubular section 6 on the pipe 3 side, and a second end plate 8 provided at the end of the tubular section 6 on the opposite side to the pipe 3 side. The accommodation section 4 suppresses or prevents the inflow of air or fluid into the inside of the pipe 3.

[0033] The tubular portion 6 is made of, for example, steel, and is a cylindrical member. The wall thickness of the tubular portion 6 is, for example, 1 mm, and the length in the axial direction is 20 mm. When the outer diameter of the pipe 3 is, for example, 12 mm, the inner diameter of the tubular portion 6 is approximately 20 mm. The tubular portion 6 is fixed to the pipe 3 via a first end plate 7 so that the axis of the tubular portion 6 coincides with the axis of the pipe 3. The first end plate 7 is connected to the pipe 3 and the tubular portion 6 by, for example, brazing. Unlike welding, brazing eliminates the risk of damage due to excessive melting of the pipe 3 and the tubular portion 6.

[0034] A through hole is formed in the first end plate 7, and the pipe 3 passes through the center of the first end plate 7. Therefore, the pipe 3 is inserted into the inside of the housing part 4 at one end of the housing part 4. The first end plate 7 is made of steel, for example.

[0035] A through hole is formed in the second end plate 8, and a terminal rod 9 constituting the terminal portion 5 passes through the center of the second end plate 8. The second end plate 8 is made of an insulating material and ensures electrical insulation to prevent creeping discharge between the pipe 3 and the terminal portion 5. The second end plate 8 is made of ceramics such as alumina or steatite.

[0036] The inside of the storage section 4 is filled with a synthetic resin material. The synthetic resin material is, for example, epoxy resin 15. The epoxy resin 15 can prevent high-humidity air from flowing into the inside of the pipe 3. In addition, since the outer peripheral surface of the end of the pipe 3 is covered by the storage section 4, the epoxy resin 15 is filled between the inner surface of the tubular section 6 in the storage section 4 and the outer peripheral surface of the pipe 3. Therefore, unlike the case where the epoxy resin 15 is filled only inside the end of the pipe 3, there is less risk of voids being generated due to deterioration of the epoxy resin 15, and it is possible to reliably prevent high-humidity air from flowing into the inside of the pipe 3.

[0037] Silicone resin 16 is provided on the second end plate 8 side inside the storage unit 4. The second end plate 8 is arranged so as to be in contact with the silicon resin 16. The silicon resin 16 can prevent fluid from flowing into the storage unit 4 and the pipe 3.

[0038] The terminal portion 5 has a terminal rod 9 and is connected to the heating wire 2. The terminal portion 5 is provided closer to the end than the pipe 3. The terminal portion 5 can be connected to an external power source, and electricity is supplied to the heating wire 2 via the terminal portion 5.

[0039] Next, a method for manufacturing the heater 1 will be described. First, a pipe 3 having a straight shape is prepared or manufactured. Then, the heating wire 2 is passed through the inside of the pipe 3. Before the heating wire 2 is passed through the pipe 3, it is preferable that a terminal rod 9 constituting a terminal portion 5 is connected to an end of the heating wire 2. After the heating wire 2 is placed in the pipe 3, the inside of the pipe 3 is filled with an insulating material such as magnesium oxide.

[0040] Next, the pipe 3 is subjected to cold forging, which is a plastic processing at room temperature, for example, to reduce the outer diameter and inner diameter of the pipe 3. This allows the air inside the pipe 3 to be discharged to the outside, and the packing density of the insulating material such as magnesium oxide filled in the pipe 3 can be increased.

[0041] Then, the pipe 3 is bent to form the pipe 3 into a shape that fits the outer circumferential surface of the protective tube 13. By the bending, for example, a structure having the above-mentioned first bent portion 3a and second bent portion 3b is formed.

[0042] Thereafter, terminal processing is performed on the end of the pipe 3. First, a first end plate 7 is attached by brazing to the end of the pipe 3 on which the heating wire 2 and insulating material are installed. Then, the cylindrical portion 6 is fixed to the first end plate 7 by welding. After that, epoxy resin 15 is filled inside the cylindrical portion 6 and dried. Furthermore, silicone resin 16 is filled on the end side of the cylindrical portion 6 and dried. After the silicone resin 16 has dried, a second end plate 8 is brought into contact with the end of the cylindrical portion 6 and screwed with a nut 17 to form the terminal portion 5.

[0043] As described above, according to this embodiment, the end of the pipe 3 of the heater 1 is sealed by the housing 4. The housing 4, which is larger than the outer diameter of the pipe 3, is installed so as to cover the outer circumferential surface of the pipe 3, and the inside of the housing 4 is filled with a synthetic resin material (e.g., epoxy resin 15). In addition, since the epoxy resin 15 is sealed by the silicon resin 16, the second end plate 8, etc., the end of the pipe 3 is highly sealed. This makes it possible to suppress or prevent the inflow of high-humidity air from the end of the pipe 3. As a result, it is possible to prevent a decrease in the insulation resistance of the heater 1 due to the inflow of high-humidity air, and it is difficult to cause a problem that the heater 1 cannot be powered on and the insulator 20 cannot be dried. In addition, when the operating condition is set such that the application of a voltage (charging) to the discharge electrode is permitted only when the temperature condition of the protective tube 13 is satisfied, the temperature does not decrease due to the power not being turned on to the heater 1, and therefore the problem of being unable to operate the electrostatic precipitator does not occur.

[0044] The insulator protection heater according to the present disclosure is not limited to heating the periphery of the insulator 20 of a wet electrostatic precipitator, but can also be applied to heating the periphery of the insulator 20 of a dry electrostatic precipitator.

[0045] FIG. 5 shows the arrangement of the insulator 20 and heater 1 in a dry electrostatic precipitator. Unlike the case of a wet electrostatic precipitator, the insulator 20 is not surrounded by the heat-insulating exterior plate 12, protective tube 13, or heat-insulating material 14. In the dry electrostatic precipitator, the heater 1 and the reflector 18 are disposed around the insulator 20. The configurations of the insulator 20 and the heater 1 are similar to those in the above-described embodiment, and detailed description will be omitted. The reflector 18 is disposed around the heater 1 on the outside opposite to the insulator 20 side so as to surround the heater 1. This allows the heater 1 to efficiently heat the insulator 20.

[0046] 5, the heater 1 is installed at a substantially constant distance from the outer peripheral surface of the insulator 20 and is provided along the outer peripheral surface of the insulator 20. The outer peripheral surface of the insulator 20 is heated by the heater 1, so that the insulator 20 is brought into a dry state. By drying the insulator 20, damage to the insulator 20 due to creeping discharge caused by moisture condensation on the surface of the insulator 20 is prevented.

[0047] The heater 1 according to the present disclosure is not limited to cases where a heater 1 is newly manufactured, but can also be applied to cases where an end of a heater that has already been installed along the outer circumferential surface of the protective cylinder 13 of an electrostatic dust collector or in the circumferential direction away from the outer circumferential surface of the insulator 20 is replaced and modified. As shown in Fig. 2, since the accommodating portion 4 and the terminal portion 5 in the heater 1 according to the present disclosure are compact, the length of the straight portion from the second bent portion 3b to the terminal portion 5 can be the same as the length of the straight portion of a conventional heater.

[0048] The heater, the electrostatic precipitator, and the method for manufacturing the heater according to the above-described embodiments can be understood, for example, as follows. The heater (1) of the present disclosure comprises an electric heating wire (2), a pipe (3) with the electric heating wire disposed therein, a storage section (4) disposed at the end of the pipe so as to surround the outer periphery of the pipe and filled with a synthetic resin material (15), and a terminal section (5) provided on the opposite side of the storage section from the pipe, connected to the electric heating wire and connectable to an external power source.

[0049] According to this configuration, the heating wire is disposed inside the pipe and is protected by the pipe, and a storage section is provided at the end of the pipe, which suppresses or prevents the inflow of air or fluid into the inside of the pipe. The inside of the storage section is filled with a synthetic resin material, for example, epoxy resin. Since the outer periphery of the end of the pipe is surrounded by the storage section and the storage section is filled with the synthetic resin material, unlike the case where the synthetic resin material is filled only inside the end of the pipe, it is possible to reliably prevent the inflow of high humidity air into the inside of the pipe. The terminal section is connected to the heating wire and is provided on the opposite side of the storage section from the pipe side. Since the terminal section can be connected to an external power source, electricity is supplied to the heating wire via the terminal section.

[0050] In the heater according to the present disclosure, the housing may have a hollow tubular portion (6), and the pipe may be inserted into the tubular portion at one end thereof.

[0051] According to this configuration, the pipe is inserted into the hollow cylindrical part at one end thereof, whereby a synthetic resin material is filled between the inner surface of the cylindrical part in the housing part and the outer peripheral surface of the pipe, reliably preventing high humidity air from flowing into the pipe.

[0052] In the heater according to the present disclosure, the inside of the housing may be filled with epoxy resin (15) as the synthetic resin material, and silicone resin (16) may be provided at the end of the housing opposite to the pipe side.

[0053] According to this configuration, the silicone resin is placed at the end of the container opposite to the end on the pipe side, and the silicone resin can prevent fluid from flowing into the container or the pipe. Also, the inside of the container is filled with epoxy resin as a synthetic resin material, and the epoxy resin can prevent high humidity air from flowing into the pipe.

[0054] The electric dust collector according to the present disclosure includes the above-mentioned heater, a discharge electrode constituting an electric dust collecting section, and an insulator (20) that supports an electric conductor (24) connected to the discharge electrode and on which the heater is installed along its outer peripheral surface.

[0055] According to this configuration, the insulator supports the electric conductor, and the electric conductor is connected to the discharge electrode that constitutes the electric dust collecting unit. The insulator is heated by a heater installed along the outer circumferential surface of the insulator, thereby bringing the insulator into a dry state.

[0056] A method of manufacturing a heater according to the present disclosure includes the steps of connecting a terminal portion to an end of a heating wire, placing the heating wire inside a pipe, installing a accommodating portion at the end of the pipe so as to surround the outer periphery of the pipe, filling the inside of the accommodating portion with a synthetic resin material, and providing the terminal portion on the side of the accommodating portion opposite the pipe.

[0057] According to this configuration, the heating wire is disposed inside the pipe and is protected by the pipe, and a storage section is provided at the end of the pipe, which suppresses or prevents the inflow of air or fluid into the inside of the pipe. The inside of the storage section is filled with a synthetic resin material, for example, epoxy resin. Since the outer periphery of the end of the pipe is surrounded by the storage section and the storage section is filled with the synthetic resin material, unlike the case where the synthetic resin material is filled only inside the end of the pipe, it is possible to reliably prevent the inflow of high humidity air into the inside of the pipe. The terminal section is connected to the heating wire and is provided on the opposite side of the storage section from the pipe side. Since the terminal section can be connected to an external power source, electricity is supplied to the heating wire via the terminal section. [Explanation of symbols]

[0058] 1: Heater for protecting insulators (heater) 2: Heating wire 3: Pipe 3a: First bend 3b: Second bend 4: Storage section 5:Terminal section 6: Cylindrical part 7: 1st end plate 8: 2nd end plate 9: Terminal bar 12: Heat insulation exterior plate 13:Protective tube (cylindrical part) 14: Heat insulation material 15: Epoxy resin 16: Silicone resin 17: Nut 18:Reflector 20: Insulator 22: Support part 24: Electrical conductor 30: Interior space 32: Ceiling material

Claims

1. Heating wire and A pipe having the heating wire disposed therein; a housing portion having a hollow tubular portion, the housing portion being disposed at an end of the pipe so as to surround an outer periphery of the pipe, the housing portion being filled with a synthetic resin material; a terminal portion having a terminal rod, being provided on the opposite side of the housing portion from the pipe side, being connectable to an external power source, the terminal rod being connected to the heating wire; an end plate through which the terminal rod passes and which is provided in contact with an end of the cylindrical portion; a nut that is screwed onto the terminal rod to bring the end plate into contact with the end of the cylindrical portion; A heater comprising:

2. A heater as described in claim 1, wherein the pipe is inserted inside the tubular portion at one end of the tubular portion.

3. The inside of the container is filled with epoxy resin as the synthetic resin material, 3. The heater according to claim 1, wherein a silicone resin is provided at an end of the housing portion opposite to the pipe side.

4. A heater according to any one of claims 1 to 3; A discharge electrode constituting an electric dust collecting unit; an insulator supporting an electric conductor connected to the discharge electrode and having the heater disposed along an outer circumferential surface thereof; An electrostatic precipitator comprising:

5. A step of connecting a terminal portion having a terminal rod to an end of the heating wire; disposing the heating wire inside a pipe; A step of installing a container having a hollow cylindrical portion at an end of the pipe so as to surround an outer periphery of the pipe; filling the inside of the cylindrical portion of the storage portion with a synthetic resin material; providing the terminal portion on a side opposite to the pipe side in the housing portion; a step of inserting the terminal rod through an end plate and screwing a nut onto the terminal rod to bring the end plate into contact with an end of the cylindrical portion by the nut; A method for manufacturing a heater comprising:

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