An electric heating device

Abstract

This invention discloses an electric heating device, comprising: a housing, the interior of which is formed into a cavity for holding a medium to be heated; a sleeve, the sleeve having a first end and a second end, the first end of the sleeve being fixedly installed to the housing, and the inner cavity of the sleeve communicating with the cavity of the housing; an electric heating tube, one end of which is located outside the sleeve, and the other end of which passes through the sleeve and is located inside the cavity of the housing; a pressure cap, the end of the electric heating tube located outside the sleeve being detachably connected to the sleeve via the pressure cap; and a sealing module, the sealing module including a first sealing structure and / or a second sealing structure. The electric heating device provided by this invention ensures reliable sealing of the entire device while maintaining a detachable connection between the electric heating tube and the sleeve for convenient on-site maintenance and replacement.

Description

Technical Field

[0001] This invention relates to the field of solar thermal power generation and energy storage technology, and in particular to an electric heating device. Background Technology

[0002] In recent years, with the rapid development of the social economy, people's demand for energy has been increasing. In order to reduce the use of fossil fuels and reduce dependence on fossil fuels, new energy sources such as solar power and wind power have received widespread attention. However, solar and wind power have uncontrollable intermittency, randomness and volatility, which makes their power output extremely unstable and will have a great impact on the power grid. In order to ensure the safety and stability of the power grid, the excess power generated by solar power and wind power systems must be discarded, resulting in a serious problem of power curtailment. At the same time, due to the current low electricity consumption at night and high electricity consumption during the day, a large peak-valley difference will be caused, which will also cause a large amount of power loss.

[0003] To reduce energy waste, utilizing off-peak electricity and surplus electricity from solar and wind power systems to drive electric heating devices to heat the thermal storage medium, converting electrical energy into heat energy for efficient storage and releasing heat when needed, is an effective means of improving energy utilization.

[0004] Currently, electric heating devices are commonly used to heat molten salt for energy storage. Since electric heating devices are often used in high-temperature environments, they require a certain level of sealing. In the current technology, electric heaters usually require welding to assemble resistance heating elements and other related components. Although this method ensures sealing, it can cause inconvenience in maintenance when the electric heating tube needs to be disassembled. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an electric heating device in which the electric heating tube is detachably connected to the sleeve via a pressure cap, facilitating on-site inspection and replacement of the electric heating tube. This avoids the problems of traditional welding connections between the electric heating tube and the shell affecting the overall quality of the electric heating device and preventing online maintenance and repair. Furthermore, by having the pressure cap contact the first sealing structure and apply a compressive force to the first sealing structure, a sealing fit is formed between the first sealing structure and the end face or inner wall of the second end of the sleeve under the action of the compressive force. This ensures the detachable connection between the electric heating tube and the sleeve for convenient on-site inspection and replacement while also guaranteeing the airtightness of the entire electric heating device.

[0006] A first aspect of the present invention provides an electric heating device comprising:

[0007] A housing, the interior of which is formed into a cavity for holding the medium to be heated;

[0008] A sleeve, comprising a first end and a second end, wherein the first end of the sleeve is fixedly installed to the housing, and the inner cavity of the sleeve is in communication with the cavity of the housing;

[0009] An electric heating element, one end of which is located outside the sleeve, and the other end of which passes through the sleeve and is located inside the cavity of the housing;

[0010] A pressure cap is provided, wherein one end of the electric heating element located outside the sleeve is detachably connected to the sleeve via the pressure cap;

[0011] A sealing module, comprising a first sealing structure and / or a second sealing structure; the first sealing structure is disposed on the outer surface of the electric heating tube, the pressure cap contacts the first sealing structure and applies a compressive force to the first sealing structure, and under the action of the compressive force, a sealing fit is formed between the first sealing structure and the end face or inner wall of the second end of the sleeve; when the sealing module includes a second sealing structure, a sealing medium is filled between the inner wall of the second end of the sleeve and the electric heating tube, the sealing medium being able to switch between a first physical form and a second physical form, the sealing medium being able to form the second sealing structure in the first physical form, and the sealing medium being able to release the second sealing structure in the second physical form, wherein the sealing medium and the medium to be heated are of the same kind of substance or different kinds of substance.

[0012] In one embodiment of the present invention, the gland has a first stepped surface;

[0013] The first sealing structure includes a sealing sleeve, which is disposed outside the electric heating tube;

[0014] Under the pressure, the two axial end faces of the sealing sleeve contact the first stepped surface and the second end of the sleeve respectively to form a sealing fit; or,

[0015] Under the pressure, the axial end face of the sealing sleeve facing the first step surface contacts the first step surface to form a sealing fit, and the outer wall of the sealing sleeve contacts the inner wall of the sleeve to form a sealing fit.

[0016] In one embodiment of the present invention, the sealing sleeve is sleeved outside the electric heating tube; the axial end face of the sealing sleeve facing the first step surface contacts the first step surface to form a sealing fit;

[0017] The sealing sleeve has a tapered outer wall that gradually expands outward from bottom to top at one end facing the sleeve and / or the sleeve has a tapered inner wall that gradually expands outward from bottom to top.

[0018] In one embodiment of the present invention, the taper of the outer tapered wall is 0.02 to 1°, and the taper of the inner tapered wall is 0.02 to 1°;

[0019] The sealing sleeve has a tapered outer wall that gradually expands outward from bottom to top at one end facing the sleeve, and the sleeve has a tapered inner wall that gradually expands outward from bottom to top. The taper of the outer wall is equal to the taper of the inner wall, and a sealing fit is formed between the outer wall and the inner wall under the action of the extrusion force.

[0020] In one embodiment of the present invention, the sealing sleeve is wrapped around the electric heating tube, and under the action of the extrusion force, the two axial end faces of the sealing sleeve respectively contact the first step surface and the second end of the sleeve to form a sealing fit.

[0021] In one embodiment of the present invention, the second end of the sleeve is provided with a sealing packing, the gland contacts the sealing packing and applies a compressive force to the sealing packing, and the sealing packing is compressed under the action of the compressive force to form the first sealing structure.

[0022] In one embodiment of the present invention, the pressure cap, the sleeve, and the electric heating tube are arranged coaxially.

[0023] In one embodiment of the present invention, the electric heating device further includes a temperature control module disposed outside the sleeve, the temperature control module being configured to change the physical state of the sealing medium filled between the inner wall of the sleeve and the electric heating tube.

[0024] In one embodiment of the present invention, the sealing module further includes a sealing gasket disposed between the gland and the sleeve.

[0025] In one embodiment of the invention, the gland further has a second stepped surface for cooperating with the sleeve to press the sealing gasket.

[0026] In one embodiment of the present invention, the gland and the sleeve are threaded together.

[0027] In one embodiment of the present invention, the outer wall of the pressure cap is provided with a disassembly notch.

[0028] In one embodiment of the present invention, the medium to be heated and / or the sealing medium is molten salt.

[0029] In one embodiment of the present invention, a retaining ring is provided inside the sleeve or on the outer wall of the electric heating tube. The inner ring of the retaining ring is in a sealing fit with the outer wall of the electric heating tube, and the outer ring of the retaining ring is in a sealing fit with the inner wall of the sleeve. The retaining ring is used to block the communication between the cavity of the housing and the inner cavity of the sleeve. The sealing medium is filled in the sleeve and is located in the region between the retaining ring and the second end of the sleeve.

[0030] In one embodiment of the present invention, the first physical state is solid, and the second physical state is one of liquid, molten or gas.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. In the electric heating device provided in this embodiment of the invention, the electric heating tube is detachably connected to the sleeve via a pressure cap, making the disassembly and assembly of the electric heating tube more convenient and facilitating on-site inspection and replacement of the electric heating tube. This avoids the problems of traditional direct welding connection between the electric heating tube and the shell affecting the overall quality of the electric heating device and making online maintenance and repair impossible. Furthermore, in the electric heating device provided in this embodiment of the invention, the pressure cap contacts the first sealing structure and applies a compressive force to the first sealing structure. Under the action of the compressive force, a tight sealing fit is formed between the first sealing structure and the end face or inner wall of the second end of the sleeve. This ensures that the detachable connection between the electric heating tube and the sleeve facilitates on-site inspection and replacement while ensuring the reliable sealing of the entire electric heating device.

[0033] 2. The electric heating device provided in this embodiment of the invention further includes a second sealing structure. A temperature control module controls the sealing medium to switch between a first physical state and a second physical state. The sealing medium can form the second sealing structure in the first physical state, and the sealing medium can release the second sealing structure in the second physical state. The sealing medium and the medium to be heated are of the same or different types of substances. For example, when both the sealing medium and the medium to be heated are molten salts, and the electric heating device is in operation, the molten salt has a higher freezing point, and solidifies at a low temperature to achieve self-sealing. The sealing effect is such that when the electric heating tube needs to be replaced, the temperature control module makes the molten salt between the inner wall of the first end of the sleeve and the electric heating tube melt, which facilitates the disassembly and assembly of the entire electric heating device. In another embodiment, when the electric heating device is working, the temperature of the area between the inner wall of the first end of the sleeve and the electric heating tube gradually decreases in the direction of approaching the pressure cap. The molten sealing medium between the inner wall of the first end of the sleeve and the electric heating tube can solidify due to the temperature drop, and thus cooperate with the electric heating tube and the sleeve to achieve self-sealing, improving the safety performance in the working state.

[0034] 3. In the electric heating device provided in the embodiments of the present invention, the first sealing structure achieves the sealing effect by the extrusion force provided by the pressure cap. Therefore, even if the first sealing structure is worn, leakage can be avoided by tightening the pressure cap and adjusting the extrusion force provided by the pressure cap, making the maintenance and repair of the molten salt electric heating device more convenient.

[0035] 4. In the electric heating device provided in the embodiments of the present invention, a sealing gasket is used between the pressure cap and the sealing sleeve to further improve the sealing performance of the electric heating device.

[0036] 5. In the electric heating device provided in the embodiments of the present invention, a disassembly notch is provided on the outside of the pressure cap to facilitate the adjustment of the tightness of the pressure cap.

[0037] 6. In order to reduce energy waste, the electric heating device provided in this embodiment of the invention uses either the surplus electricity or off-peak electricity from a solar power generation system or a wind power generation system to power the electric heating tube. The surplus electricity or off-peak electricity from the solar power generation system or the wind power generation system drives the electric heating tube to heat the heat storage medium, so that electrical energy is converted into heat energy for efficient storage and released when needed. This is an effective means to improve energy utilization.

[0038] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the electric heating device provided in an embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram of a first sealing structure provided in an embodiment of the present invention.

[0041] Figure 3 This is a schematic diagram of another first sealing structure provided in an embodiment of the present invention.

[0042] In the diagram: 10, sleeve; 20, gland; 201, first step surface; 202, second step surface; 30, electric heating tube; 31, lead-out rod; 40, housing; 50, sealing sleeve; 61, cavity one; 62, cavity two; 70, junction box housing; 80, temperature control module; 91, molten salt pipeline; 92, molten salt tank; 93, molten salt valve; 94, retaining ring. Detailed Implementation

[0043] The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and modifications without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0044] In existing electric heaters, the connection between the heating element and the shell is generally achieved by welding. This makes the potting process of the heating element more complex, affecting the overall quality of the electric heater. At the same time, it makes it impossible to perform online maintenance and repair of the electric heater, which is not conducive to the large-scale application of electric heaters in the field of energy storage.

[0045] To address the aforementioned technical problems, this invention provides an electric heating device with a detachable connection between the electric heating tube and the sleeve, which is simple, convenient, and enables online maintenance and repair of the electric heating device. When the electric heating devices are detachably connected, to ensure that the electric heating devices still achieve sealing performance comparable to or even better than welded connections, the electric heating device provided by this invention ensures the overall sealing performance of the electric heating device through a first sealing structure and a second sealing structure, thereby improving the overall quality of the electric heating device. Specifically, by having a pressure cap contact the first sealing structure and apply extrusion pressure to the first sealing structure, a sealing fit is formed between the first sealing structure and the end face or inner wall of the second end of the sleeve, thus forming a first seal. The sealing medium filling the space between the inner wall of the second end of the sleeve and the electric heating tube transforms into a solid state, achieving self-sealing and forming a second seal.

[0046] Furthermore, in recent years, with the rapid development of the social economy, people's demand for energy has been increasing. In order to reduce the use of fossil fuels and decrease dependence on them, new energy sources such as solar power and wind power have received widespread attention. However, solar and wind power have uncontrollable intermittency, randomness, and volatility, resulting in extremely unstable power output, which can cause significant impacts on the power grid. To ensure the safety and stability of the power grid, excess electricity generated by solar and wind power systems must be discarded, resulting in a serious problem of power curtailment. At the same time, due to the current low electricity consumption at night and high electricity consumption during the day, a large peak-valley difference occurs, also causing significant power losses. To reduce energy waste, the electric heating device provided in this embodiment of the invention uses either the curtailed electricity or off-peak electricity from solar or wind power systems to power the electric heating tube. The curtailed electricity or off-peak electricity from solar or wind power systems drives the electric heating tube to heat the heat storage medium, converting electrical energy into heat energy for efficient storage and releasing heat when needed. This is an effective means to improve energy utilization.

[0047] The present invention will now be described in detail with reference to specific embodiments.

[0048] Example 1

[0049] Reference Figure 1 As shown, this embodiment provides an electric heating device, including:

[0050] The housing 40 has an interior cavity for holding the medium to be heated;

[0051] The sleeve 10 includes a first end and a second end. The first end of the sleeve 10 is fixedly installed with the housing 40, and the inner cavity of the sleeve 10 is in communication with the cavity of the housing 40.

[0052] An electric heating element 30 has one end located outside the sleeve 10 and the other end passing through the sleeve 10 and located inside the cavity of the housing 40.

[0053] The end of the electric heating element 30 located outside the sleeve 10 is detachably connected to the sleeve 10 via the pressure cap 20;

[0054] The sealing module includes a first sealing structure and / or a second sealing structure. The first sealing structure is disposed on the outer surface of the electric heating tube 30. The pressure cap 20 contacts the first sealing structure and applies a compressive force to the first sealing structure. Under the action of the compressive force, a sealing fit is formed between the first sealing structure and the inner wall of the sleeve 10. When the sealing module includes a second sealing structure, a sealing medium is filled between the inner wall of the second end of the sleeve 10 and the electric heating tube 30. The sealing medium can switch between a first physical state and a second physical state. The sealing medium can form a second sealing structure in the first physical state and can release the second sealing structure in the second physical state. The sealing medium and the medium to be heated are of the same kind or different kinds of substances. It should be noted that in this embodiment, when the sealing module includes a second sealing structure, the first physical state of the sealing medium is solid, and the second physical state is one of liquid, molten, or gas. Specifically, the sealing medium has at least two physical states, including solid and liquid, solid and molten, or solid and gas (e.g., sublimation). The sealing medium can be changed between the two physical states by changing the temperature. In addition, it should be noted that the change of the sealing medium to different physical states is not limited to changing the physical state by changing the temperature. Furthermore, in practical applications, a small amount of the sealing medium may overflow outside the sleeve 10, such as overflowing into the gap where the first sealing structure and the gland 20 meet, or into the gap where the first sealing structure and the second end of the sleeve 10 meet. Therefore, although the sealing medium is initially filled between the inner wall of the sleeve 10 and the electric heating tube 30, the second sealing structure may eventually be formed outside the sleeve 10, inside the sleeve 10, or both inside and outside the sleeve 10.

[0055] When the sealing medium and the medium to be heated are the same type of substance, since the inner cavity of the sleeve 10 and the cavity of the shell 40 are interconnected, the medium to be heated located in the cavity of the shell 40 can directly enter the inner cavity of the sleeve 10 and transform into a solid state to form a second sealing structure. At this time, the medium to be heated needs to be able to switch between the first physical form and the second physical form. The medium to be heated can form the second sealing structure in the first physical form and can release the second sealing structure in the second physical form. When the sealing medium and the medium to be heated are different types of substances or the sealing module does not include a second sealing structure, there is no restriction on the physical form required for the medium to be heated.

[0056] Reference Figure 2 As shown, the pressure cap 20 has a first stepped surface 201 inside;

[0057] The first sealing structure includes a sealing sleeve 50, which surrounds the electric heating tube and is coaxially arranged with the electric heating tube 30. Under the action of extrusion pressure, the axial end face of the sealing sleeve 50 facing the first step surface 201 contacts the first step surface 201 to form a sealing fit, and the outer wall of the sealing sleeve 50 contacts the inner wall of the sleeve 10 to form a sealing fit.

[0058] The sealing sleeve 50 has a tapered outer wall that gradually expands outward from bottom to top at one end facing the sleeve 10, and the sleeve 10 has a tapered inner wall that matches the tapered inner wall. Under the action of extrusion pressure, a sealing fit is formed between the tapered outer wall and the tapered inner wall.

[0059] In another embodiment, a tapered outer wall may be provided only on the sealing sleeve 50, and a sealing fit may be formed between the tapered outer wall and the inner wall of the sleeve 10 under the action of extrusion pressure. Alternatively, a tapered inner wall may be provided only inside the sleeve 10, and a sealing fit may be formed between the outer wall of the sealing sleeve 50 and the tapered inner wall under the action of extrusion pressure.

[0060] Preferably, the taper of both the outer and inner walls of the tapered structure is 0.02 to 1°.

[0061] When both the tapered outer wall and the tapered inner wall are present, a sealing fit is formed between them under the action of extrusion pressure. Through the fit between the tapered inner wall and the tapered outer wall, when the gland 20 extrudes the sealing sleeve 50 and the sleeve 10, the sleeve 10 and the gland 20 exert an upward force on the electric heating tube 30 through the sealing sleeve 50. At the same time, the sealing sleeve 50 deforms under the force, and the increased contact area increases the friction, which helps to form a sealing fit between the sealing sleeve 50 and the sleeve 10, and between the gland 20 and the sleeve 10, to fix the electric heating tube 30. When the gland 20 is removed, the sealing sleeve 50 and the sleeve 10 are no longer subjected to the extrusion force of the gland 20, and the electric heating tube 30 can be removed at this time.

[0062] In one embodiment, the sealing sleeve 50 can be fixedly installed outside the electric heating tube 30; the sealing sleeve 50 can also be tightly press-fitted with the electric heating tube 30, and the sealing sleeve can slide along the axial direction of the electric heating tube. It should be noted that the connection relationship between the sealing sleeve 50 and the electric heating tube 30 is not limited to the above selection. Any connection method that can ensure that the medium to be heated will not pass through the joint surface between the sealing sleeve 50 and the electric heating tube 30 can be applied to the present invention.

[0063] In this embodiment, the heating medium can be molten salt.

[0064] In this embodiment, both the heating medium and the sealing medium can be molten salt.

[0065] The electric heating device in this embodiment also includes a temperature control module 80 disposed outside the sleeve 10. The temperature control module 80 is configured to change the physical state of the sealing medium filled between the inner wall of the second end of the sleeve 10 and the electric heating tube 30. By controlling the temperature of the sleeve 10, the physical state of the sealing medium filled between the inner wall of the second end of the sleeve 10 and the electric heating tube 30 is controlled (e.g., changes between solid or molten / liquid / gas state). When the electric heating device is in operation, the sealing medium filled between the inner wall of the second end of the sleeve 10 and the electric heating tube 30 changes to a solid state to achieve a self-sealing effect. When the electric heating device is not in operation and the electric heating tube 30 needs to be inspected online, the sealing medium filled between the inner wall of the second end of the sleeve 10 and the electric heating tube 30 changes to a molten, liquid, or gas state to facilitate the disassembly of the electric heating tube 30. The temperature control module has heating and / or cooling functions. In practical applications, whether the temperature control module has heating, cooling, or both functions depends on the physical properties of the sealing medium and the actual application environment. For example, when the electric heating device is working, the temperature at the location of the sealing medium is higher than its freezing point, which is insufficient to cause the sealing medium to solidify. In this case, the temperature control module 80 needs to have a cooling function to lower the temperature at the location of the sealing medium and cause it to solidify. When the electric heating device is under maintenance, the temperature at the location of the sealing medium is lower than its freezing point, which is insufficient to cause it to molten, liquid, or gaseous. In this case, the temperature control module 80 needs to have a heating function to cause the sealing medium to change from solid to liquid, molten, or gaseous.

[0066] The temperature control module 80 can be detachably installed on the outside of the sleeve 10, or it can be fixedly installed on the outside of the sleeve 10.

[0067] In one embodiment, the temperature control module 80 can be a heating mechanism such as an electric heating wire or an electric heating tube, but this is not limited in this invention.

[0068] Additionally, it should be noted that the electric heating device provided by the present invention may include only the first sealing structure or the second sealing structure, or may include both the first sealing structure and the second sealing structure simultaneously.

[0069] When the sealing medium is molten salt, the gap between the sleeve 10 and the electric heating tube 30 forms cavity 61, and the cavity inside the shell 40 that stores molten salt is cavity 62. When the electric heating device is in operation, cavity 61 is filled with molten salt. The molten salt in cavity 61 near the second end of the sleeve 10 solidifies and cooperates with the electric heating tube 30 and the sleeve 10 to achieve self-sealing, thereby improving the safety performance in operation.

[0070] On the one hand, when the electric heating device is under maintenance or the electric heating tube 30 is replaced, the melting of the molten salt in cavity 61 can be achieved by heating with the temperature control module 80. On the other hand, when the electric heating device is working, the temperature of the area between the inner wall of the first end of the sleeve 10 and the electric heating tube 30 gradually decreases in the direction of approaching the pressure cap 20 (because the distance from the heating area of ​​the electric heating tube 30 is getting further and further), and the temperature can drop below the solidification point of the molten salt. Therefore, the molten salt in the molten state between the inner wall of the first end of the sleeve 10 and the electric heating tube 30 can solidify due to the temperature drop, and can then cooperate with the electric heating tube 30 and the sleeve 10 to achieve self-sealing, improving the safety performance in the working state. Therefore, in this case, the temperature control module 80 only needs to have a heating function to achieve the purpose of melting solid molten salt.

[0071] In one embodiment, the sealing module further includes a sealing gasket disposed between the gland 20 and the sleeve 10, thereby achieving a further sealing effect.

[0072] Furthermore, the gland 20 also has a second stepped surface 202 for engaging with the sleeve 10 to press the sealing gasket.

[0073] In one embodiment, the gland 20 is threadedly connected to the sleeve 10.

[0074] The end of the pressure cap 20 near the housing 40 is provided with an internal thread, and the outer wall of the sleeve 10 near the second end is provided with an external thread. The pressure cap 20 is sleeved on the outside of the electric heating tube 30. Through the cooperation of the internal thread and the external thread, the pressure cap 20 is tightened until the first step surface 201 of the pressure cap 20 forms a sealing fit with the upper end surface of the sealing sleeve 50, and the tapered outer wall of the sealing sleeve 50 forms a sealing fit with the tapered inner wall of the sleeve 10.

[0075] In one embodiment, the outer wall of the pressure cap 20 is provided with a disassembly notch, which can be used to tighten or loosen the pressure cap 20.

[0076] In one embodiment, the electric heating tube 30 has a lead-out rod 31 at one end outside the sleeve 10. The lead-out rod 31 is disposed inside a junction box, which includes a junction box housing 70. In this embodiment, the electric heating tube 30 is powered by either surplus electricity from a solar power system or wind power system, or off-peak electricity. This allows the surplus or off-peak electricity to be converted into heat energy for efficient storage and released as needed, which is an effective means of improving energy utilization.

[0077] In one embodiment, the electric heating device includes a plurality of sleeves 10, each sleeve 10 corresponding to an electric heating tube 30. In one embodiment, the sealing sleeves 50 can be centrally symmetrically distributed about the central axis of the electric heating tube 30. When the axial end face of the sealing sleeve 50 facing the first step surface 201 contacts the first step surface 201 to form a tight seal, the central axis of the sealing sleeve 50 coincides with the central axis of the sleeve 10, avoiding the problem of the electric heating tube 30 breaking due to uneven force. In addition, the sealing sleeve 50 in this embodiment is made of insulating material, further ensuring the safety of the entire electric heating device.

[0078] Preferably, in this invention, the pressure cap 20, the sleeve 10, and the electric heating tube 30 are arranged coaxially.

[0079] The electric heating device in this embodiment also includes a molten salt pipe 91. One end of the molten salt pipe 91 is connected to the cavity of the shell 40, and the other end is connected to the molten salt tank 92. A molten salt valve 93 is provided on the molten salt pipe 91.

[0080] In this embodiment, a retaining ring 94 is also provided inside the sleeve 10 or on the outer wall of the electric heating tube 30. The inner ring of the retaining ring 94 is in a sealing fit with the outer wall of the electric heating tube 30, and the outer ring of the retaining ring 94 is in a sealing fit with the inner wall of the sleeve 10. The retaining ring 94 is used to block the communication between the cavity of the housing 40 and the inner cavity of the sleeve 10. The sealing medium is filled in the sleeve 10 and is located in the region between the retaining ring 94 and the second end of the sleeve 10. By providing the retaining ring 94, a guide can be provided for the installation of the electric heating tube 30 in the sleeve 10. At the same time, it can also prevent the heating medium from mixing with the sealing medium.

[0081] Example 2

[0082] The electric heating device provided in this embodiment differs from the electric heating device in the embodiment in that the first sealing structure in the electric heating device provided in this embodiment includes a sealing sleeve 50, and the two axial end faces of the sealing sleeve 50 are in contact and sealed with the first step surface 201 and the second end of the sleeve 10, respectively.

[0083] Reference Figure 3As shown, the sealing sleeve 50 in this embodiment is a straight cylindrical structure and is an integrally formed structure. The sealing sleeve 50 is fixedly installed outside the electric heating tube 30. The two axial ends of the sealing sleeve 50 are the first limiting surface and the second limiting surface, respectively. The electric heating tube 30 extends into the sleeve 10. The pressure cap 20 is tightened, and the pressure cap 20 generates a squeezing force on the first sealing structure. Under the action of the squeezing force, the first step surface 201 of the pressure cap 20 contacts the first limiting surface to form a sealing fit, and the second limiting surface contacts the second end of the sleeve 10 to form a sealing fit.

[0084] Alternatively, the sealing sleeve 50 in this embodiment can also be made of sealing packing. The sealing packing is provided on the end face of the second end of the sleeve 10. The first step surface 201 of the pressure cap 20 contacts the sealing packing and applies extrusion pressure to the sealing packing. The sealing packing is compressed under the extrusion pressure to form the sealing sleeve 50. The sealing packing can be graphite packing, PTFE packing, etc., and the specific selection of the sealing packing is not limited in this invention. When the sealing sleeve 50 is made of sealing packing, the sealing sleeve 50 does not need to be fixed to the outside of the electric heating tube 30. The sealing effect is achieved through the extrusion of the first step surface 201 of the pressure cap 20, the cooperation of the outer wall of the electric heating tube 30, and the end face of the second end of the sleeve 10.

[0085] The specific embodiments of this application have been described above. It should be understood that this application is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the substantive content of this application. Unless otherwise specified, the embodiments and features described in the embodiments of this application can be arbitrarily combined with each other.

Claims

1. An electric heating device, characterized in that include: A housing, the interior of which is formed into a cavity for holding the medium to be heated; A sleeve, comprising a first end and a second end, wherein the first end of the sleeve is fixedly installed to the housing, and the inner cavity of the sleeve is in communication with the cavity of the housing; An electric heating element, one end of which is located outside the sleeve, and the other end of which passes through the sleeve and is located inside the cavity of the housing; A pressure cap is provided, wherein one end of the electric heating element located outside the sleeve is detachably connected to the sleeve via the pressure cap; A sealing module, comprising a first sealing structure and / or a second sealing structure; the first sealing structure is disposed on the outer surface of the electric heating tube, the pressure cap contacts the first sealing structure and applies a compressive force to the first sealing structure, and under the action of the compressive force, a sealing fit is formed between the first sealing structure and the end face or inner wall of the second end of the sleeve; when the sealing module includes a second sealing structure, a sealing medium is filled between the inner wall of the second end of the sleeve and the electric heating tube, the sealing medium being able to switch between a first physical form and a second physical form, the sealing medium being able to form the second sealing structure in the first physical form, and the sealing medium being able to release the second sealing structure in the second physical form, wherein the sealing medium and the medium to be heated are of the same kind of substance or different kinds of substance.

2. The electric heating device according to claim 1, characterized in that The gland has a first stepped surface; The first sealing structure includes a sealing sleeve, which is disposed outside the electric heating tube; Under the pressure, the two axial end faces of the sealing sleeve contact the first stepped surface and the second end of the sleeve to form a sealing fit. or, Under the pressure, the axial end face of the sealing sleeve facing the first step surface contacts the first step surface to form a sealing fit, and the outer wall of the sealing sleeve contacts the inner wall of the sleeve to form a sealing fit.

3. The electric heating device according to claim 2, characterized in that The sealing sleeve is fitted over the electric heating tube; the axial end face of the sealing sleeve facing the first step surface contacts the first step surface to form a sealing fit; The sealing sleeve has a tapered outer wall that gradually expands outward from bottom to top at one end facing the sleeve and / or the sleeve has a tapered inner wall that gradually expands outward from bottom to top.

4. The electric heating device according to claim 3, characterized in that The taper of the outer wall of the tapered structure is 0.02 to 1°, and the taper of the inner wall of the tapered structure is 0.02 to 1°. The sealing sleeve has a tapered outer wall that gradually expands outward from bottom to top at one end facing the sleeve, and the sleeve has a tapered inner wall that gradually expands outward from bottom to top. The taper of the outer wall is equal to the taper of the inner wall, and a sealing fit is formed between the outer wall and the inner wall under the action of the extrusion force.

5. The electric heating device according to claim 2, wherein The sealing sleeve surrounds the electric heating tube, and under the action of the extrusion force, the two axial end faces of the sealing sleeve contact the first step surface and the second end of the sleeve respectively to form a sealing fit.

6. The electric heating device of claim 1, wherein, The second end of the sleeve is provided with a sealing packing. The gland contacts the sealing packing and applies extrusion pressure to the sealing packing. The sealing packing is compressed under the extrusion pressure to form the first sealing structure.

7. The electric heating device of claim 1, wherein The pressure cap, the sleeve, and the electric heating tube are arranged coaxially.

8. The electric heating device of claim 1, wherein, The electric heating device also includes a temperature control module disposed outside the sleeve, the temperature control module being configured to change the physical state of the sealing medium filled between the inner wall of the sleeve and the electric heating tube.

9. The electric heating device of claim 1, wherein, The sealing module also includes a sealing gasket disposed between the gland and the sleeve.

10. The electric heating device according to claim 9, characterized in that The gland also has a second stepped surface for engaging with the sleeve to press the sealing gasket.

11. An electric heating device according to any of claims 1-10, characterised in that The gland and the sleeve are threaded together.

12. The electrically heated apparatus of claim 11, wherein, The outer wall of the pressure cap has a disassembly notch.

13. The electrically heated apparatus of claim 1, wherein, The medium to be heated and / or the sealing medium is molten salt.

14. The electric heating device of claim 1, wherein, A retaining ring is provided inside the sleeve or on the outer wall of the electric heating tube. The inner ring of the retaining ring is sealed to the outer wall of the electric heating tube, and the outer ring of the retaining ring is sealed to the inner wall of the sleeve. The retaining ring is used to block the communication between the cavity of the shell and the inner cavity of the sleeve. The sealing medium is filled in the sleeve and is located in the region between the retaining ring and the second end of the sleeve.

15. The electrically heated apparatus of claim 1 wherein, The first physical state is solid, and the second physical state is one of liquid, molten or gas.

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