Rope type high-voltage electric heater

Abstract

The utility model relates to the technical field of electric heaters, in particular to a rope type high-voltage electric heater. Comprising a pressure vessel cylinder; the rope type electric heating core is coaxially inserted into the pressure container cylinder; wherein the rope type electric heating core comprises a heating cable and a central cylinder; the heating cable is spirally and uniformly wound on the outer surface of the central cylinder; the heating cable comprises a tubular heating element, a magnesium oxide powder layer and a metal shell. The tubular heating element is coaxially inserted into the metal shell, and the magnesium oxide powder layers are filled in the tubular heating element and between the tubular heating element and the metal shell. The utility model fills up the application blank of high-temperature and high-voltage heating occasions, and is particularly suitable for heating application of gas and fused salt.

Description

Technical Field

[0001] The utility model relates to the technical field of electric heaters, in particular to a rope-type high-voltage electric heater. Background Art

[0002] Generally, fluid heating adopts the traditional circulating electric heater method. The heating element adopts the form of electric heating tube, which is a spiral resistance wire embedded in magnesium oxide powder. In high-temperature and high-voltage heating situations, on the one hand, due to the uneven electric field formed between the spiral heating wire and the metal shell (including the elbow of the electric heating tube, the connection between the heating wire and the lead rod, etc.), the insulating material is easy to break down. On the other hand, the electric heating tube adopts a multi-branch series connection to meet the needs of high voltage input, resulting in many contacts and indirectly causing the equipment to malfunction. In addition, since the electric heating tube adopts the method of filling vibrating powder with magnesium oxide and the process of re-shrinking the tube, it is easy to cause the eccentricity of the heating wire in the tube, which also affects the high voltage withstand test. Utility Model Content

[0003] The utility model aims to provide a rope-type high-voltage electric heater, which fills the application gap of high-temperature and high-voltage heating occasions and is particularly suitable for heating applications of gas and molten salt.

[0004] In order to solve the above technical problems, the utility model provides a rope-type high-voltage electric heater, comprising:

[0005] Pressure vessel cylinder;

[0006] A rope-type electric heating core is coaxially plugged into the pressure vessel barrel;

[0007] The rope-type electric heating core comprises: a heating cable and a central tube; the heating cable is spirally and evenly wound on the outer surface of the central tube;

[0008] The heating cable comprises: a tubular heating element, a magnesium oxide powder layer and a metal shell; the tubular heating element is coaxially inserted into the metal shell, and the magnesium oxide powder layer is filled in the tubular heating element and between the tubular heating element and the metal shell.

[0009] Preferably, the rope-type electric heating core also includes a lead-out cable, and the two lead-out cables are respectively arranged at the head and tail ends of the heating cable, and the two lead-out cables are respectively used to lead out to the outside of the pressure vessel tube, and are respectively arranged close to the inlet and outlet ends of the pressure vessel tube.

[0010] Preferably, the lead-out cable and the heating cable have the same structure, and the heating cable is made of a high-resistivity alloy material, and the lead-out cable is made of a low-resistivity material.

[0011] Preferably, the tubular heating element in the heating cable is made of copper-nickel alloy, nickel-chromium alloy or iron-chromium alloy, and the tubular heating element in the lead-out cable is made of copper or stainless steel.

[0012] Preferably, a plurality of the heating cables spirally wound on the central tube are arranged so as to be distributed in multiple layers along the radial direction of the central tube; and the minimum bending radius of the heating cable is not less than 1 m.

[0013] Preferably, the outer surface of the heating cable further includes a layer of sparsely wound stainless steel spacer wires to prevent mutual contact between the heating cables wound around the central tube.

[0014] Preferably, it further comprises a power junction box arranged outside the pressure vessel tube, and the connection terminals of the two power junction boxes are respectively connected to the lead-out cables.

[0015] Preferably, it also includes a temperature sensor, which is installed on the heating cable.

[0016] Preferably, it also includes a heat dissipation area, which is located between the pressure vessel tube and the power junction box.

[0017] Preferably, the surface heating power of the heating cable decreases from the inlet end to the outlet end of the pressure vessel barrel.

[0018] Compared with the prior art, the utility model has the following beneficial effects:

[0019] 1. The heating element of the utility model is different from the traditional electric heating tube. It adopts a structure similar to MI mineral cable. One power point can be designed to have a large power and a small number of loops. Unlike electric heating tubes, many are connected in series to meet the needs of high voltage input. There are fewer fault points than electric heating tubes: we choose conductors different from MI cables. The conductors in MI cables are usually solid metal round rods. We use tubular conductors with magnesium oxide powder inside and outside to form a coaxial uniform electric field. At the same time, the processing technology of MI cable is to pre-thread the magnesium oxide tube. Through annealing and drawing, the concentricity of the conductor and the outer shell is better than the powder shrinking tube process. Compared with traditional electric heating tubes, the dielectric strength has been further improved.

[0020] 2. The utility model provides a rope-type high-voltage electric heater, which fills the application gap in high-temperature and high-voltage heating occasions, and is particularly suitable for heating applications of high-temperature gas and high-temperature molten salt.

[0021] 3. The heating cable designed in the utility model adopts a variable power design. Under the condition of the same output power, the volume of the electric heater of the utility model, for example, a 5MW device, is 1 / 2 of the volume of a traditional electric heater. That is, for devices of the same size, the power of the electric heater of the utility model is twice that of a traditional electric heater, which greatly reduces the volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a three-dimensional diagram of a rope-type high-voltage electric heater of the utility model.

[0023] Figure 2 It is a cross-sectional view of a rope-type high-voltage electric heater of the utility model.

[0024] Figure 3 It is a three-dimensional diagram of the rope-type electric heating core in the utility model.

[0025] Figure 4 It is a stereoscopic diagram of the heating cable in the utility model.

[0026] In the figure: 1-pressure vessel cylinder, 11-inlet end, 12-outlet end, 2-rope type electric heating core, 21-heating cable, 211-tubular heating element, 212-magnesium oxide powder layer, 213-metal shell, 214-stainless steel spacer wire, 22-center cylinder, 23-lead-out cable. DETAILED DESCRIPTION

[0027] The utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the utility model will become clearer. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model.

[0028] Embodiment 1:

[0029] like Figures 1 to 4 As shown, the embodiment of the utility model provides a rope-type high-voltage electric heater, comprising: a pressure vessel tube 1; a rope-type electric heating core 2, coaxially plugged into the pressure vessel tube 1; wherein the rope-type electric heating core 2 comprises: a heating cable 21 and a central tube 22; the heating cable 21 is spirally and evenly coiled on the outer surface of the central tube 22; the pressure vessel tube 1 and the central tube 22 are both composed of conical tubes distributed at both ends and a cylindrical tube in the middle;

[0030] The heating cable 21 comprises: a tubular heating element 211, a magnesium oxide powder layer 212 and a metal shell 213; that is, the heating cable 21 adopts a structure similar to that of a mineral cable; the tubular heating element 211 is coaxially inserted into the metal shell 213, and the tubular heating element 211 and the space between the tubular heating element 211 and the metal shell 213 are filled with the magnesium oxide powder layer 212; by adopting a tubular structure for the heating element and the metal shell 213, the surface load of the heating element is further reduced, and at the same time, the tubular heating element 211 and the tubular metal shell 213 form a uniform electric field; a lower power density of the heating element is achieved, resulting in a lower temperature and a longer life.

[0031] The rope-type electric heating core 2 also includes a lead-out cable 23 , and two lead-out cables 23 are respectively arranged at the head and tail ends of the heating cable 21 , and the two lead-out cables 23 are respectively used to lead out to the outside of the pressure vessel tube 1 , and are respectively arranged close to the inlet and outlet ends of the pressure vessel tube 1 .

[0032] The lead-out cable 23 and the heating cable 21 have the same structure, and the heating cable 21 is made of a high-resistivity alloy material, while the lead-out cable 23 is made of a low-resistivity material.

[0033] The tubular heating element 211 in the heating cable 21 is made of copper-nickel alloy, nickel-chromium alloy or iron-chromium alloy, and the tubular heating element 211 in the lead-out cable 23 is made of copper or stainless steel.

[0034] There are multiple spirally wound heating cables 21 arranged on the central tube 22, so that they are distributed in multiple layers along the radial direction of the central tube 22; the minimum bending radius of the heating cable 21 is not less than 1m. Since the device is used in high voltage occasions, there is a clear limit on the bending radius of the heating cable 21, and the minimum bending radius is generally not less than 1m. Therefore, in order to meet the needs of fluid diversion and the requirements of the supporting structure of the heating cable 21, a central tube 22 with a diameter greater than 1m is placed in the center of the rope-type electric heating core 2.

[0035] In order to prevent the heating cables 21 from contacting each other when winding the central tube 22, before the heating cables 21 are wound, a sparse layer of stainless steel spacer wire 214 for preventing cable contact is pre-wound on the surface of the heating cables 21, that is, the outer surface of the heating cable 21 also includes a sparse layer of stainless steel spacer wire 214 to prevent the heating cables 21 wound on the central tube 22 from contacting each other.

[0036] It also includes a power connection box arranged outside the pressure vessel tube 1, and the connection terminals of the two power connection boxes are respectively connected to the lead-out cables 23.

[0037] It also includes a temperature sensor, which is installed on the heating cable 21.

[0038] It also includes a heat dissipation area, which is located between the pressure vessel tube 1 and the power connection box.

[0039] The surface heating power of the heating cable 21 decreases from the inlet end 11 to the outlet end 12 of the pressure vessel barrel 1 .

[0040] Embodiment 2:

[0041] like Figures 1 to 4 As shown, based on the above embodiment 1, the tubular heating element 211 generally adopts alloy materials, such as copper-nickel alloy, nickel-chromium alloy or iron-chromium alloy, etc. The tubular heating element 211 in the heating cable 21 and the tubular lead-out element in the lead-out cable 23 are made of different materials. The heating element and the lead-out element are welded before being drawn in advance. The lead-out element generally adopts low resistivity material, such as copper or stainless steel, etc.

[0042] The fluid entering from the inlet of the pressure vessel sweeps across all the heating cables 21, and has a high heat transfer coefficient, which greatly reduces the surface temperature of the heating cables 21 and prolongs the service life of the entire equipment.

[0043] Embodiment 3:

[0044] like Figures 1 to 4 As shown, on the basis of the above-mentioned embodiment 2, it also includes a power connection box arranged outside the pressure vessel tube 1, and the connection terminals of the two power connection boxes are respectively connected to the lead-out cables 23, and at the same time, it is designed to be an explosion-proof structure according to the use occasion. It also includes a temperature sensor, which is installed on the heating cable 21. It also includes a heat dissipation area, which is located between the pressure vessel tube 1 and the power connection box.

[0045] The surface heating power of the heating cable 21 decreases from the inlet to the outlet of the pressure vessel. The change in power can be achieved by setting different heating materials, different tubular thicknesses, etc.

[0046] The utility model also includes the following main technical parameters:

[0047] 1. The working voltage can reach 8.6KV;

[0048] 2. Working temperature: 650℃;

[0049] 3. Heating cable 21 diameter: 30mm;

[0050] 4. Minimum bending radius of heating cable 21: 1m.

[0051] The heating cable 21 is designed for variable power use. Under the condition of the same output power, the volume of the electric heater is 1 / 2 of the volume of the traditional electric heater. That is, for equipment of the same size, the power of the electric heater is twice that of the traditional electric heater, which greatly reduces the volume.

[0052] The above description is only a description of the preferred embodiment of the utility model, and is not any limitation on the scope of the utility model. Any changes and modifications made by ordinary technicians in the field of the utility model based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A rope-type high-voltage electric heater, characterized in that: include: Pressure vessel barrel (1); A rope-type electric heating core (2) is coaxially inserted into the pressure vessel tube (1); The rope-type electric heating core (2) comprises: a heating cable (21) and a central tube (22); the heating cable (21) is spirally and evenly wound on the outer surface of the central tube (22); The heating cable (21) comprises: a tubular heating element (211), a magnesium oxide powder layer (212) and a metal shell (213); the tubular heating element (211) is coaxially inserted into the metal shell (213), and the magnesium oxide powder layer (212) is filled inside the tubular heating element (211) and between the tubular heating element (211) and the metal shell (213).

2. A rope-type high-voltage electric heater as claimed in claim 1, characterized in that: The rope-type electric heating core (2) also includes a lead-out cable (23), wherein the two lead-out cables (23) are respectively arranged at the head and tail ends of the heating cable (21), and the two lead-out cables (23) are respectively used to be led out to the outside of the pressure vessel tube (1), and are respectively arranged close to the inlet and outlet ends of the pressure vessel tube (1).

3. A rope-type high-voltage electric heater as claimed in claim 2, characterized in that: The lead-out cable (23) and the heating cable (21) have the same structure, and the heating cable (21) is made of a high-resistivity alloy material, while the lead-out cable (23) is made of a low-resistivity material.

4. A rope-type high-voltage electric heater as claimed in claim 3, characterized in that: The tubular heating element (211) in the heating cable (21) is made of copper-nickel alloy, nickel-chromium alloy or iron-chromium alloy, and the tubular heating element (211) in the lead-out cable (23) is made of copper or stainless steel.

5. A rope-type high-voltage electric heater as claimed in claim 1, characterized in that: A plurality of the heating cables (21) spirally wound on the central tube (22) are arranged so as to be distributed in multiple layers along the radial direction of the central tube (22); the minimum bending radius of the heating cables (21) is not less than 1 m.

6. A rope-type high-voltage electric heater as claimed in claim 1, characterized in that: The outer surface of the heating cable (21) also includes a layer of sparsely wound stainless steel spacer wires (214) to prevent mutual contact between the heating cables (21) wound around the central tube (22).

7. A rope-type high-voltage electric heater as claimed in claim 2, characterized in that: It also comprises a power connection box arranged outside the pressure vessel tube (1), and the connection terminals of the two power connection boxes are respectively connected to the lead-out cables (23).

8. A rope-type high-voltage electric heater as claimed in claim 1, characterized in that: It also includes a temperature sensor, which is installed on the heating cable (21).

9. A rope-type high-voltage electric heater as claimed in claim 7, characterized in that: It also includes a heat dissipation area, which is located between the pressure vessel tube (1) and the power connection box.

10. A rope-type high-voltage electric heater according to any one of claims 1 to 9, characterized in that: The surface heating power of the heating cable (21) decreases from the inlet end (11) to the outlet end (12) of the pressure vessel barrel (1).

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