An electric heater

Abstract

The application relates to the technical field of heater devices, and particularly discloses an electric heater which comprises a metal sheet, a quartz tube and a metal cotton net, the metal sheet is arranged in an arc shape, the metal sheet comprises a containing portion and an opening portion, the opening portion is arranged opposite to a to-be-heated object, the quartz tube is arranged in the containing portion, an electric heating wire is arranged in the quartz tube, the electric heating wire is used for converting electric energy into heat energy, the metal cotton net is arranged between the metal sheet and the quartz tube, and the metal cotton net is used for absorbing thermal stress through elastic deformation to avoid rigid extrusion between the metal sheet and the quartz tube. The application has the effect of improving the problem that in the existing electric heater, thermal stress is generated between the quartz tube and a metal fixing component due to the difference in thermal expansion coefficients, and the quartz tube is prone to breakage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heater devices, and particularly to an electric heater. BACKGROUND

[0002] As a device for converting electrical energy into heat energy, the electric heater is widely used in industrial heating, household heating, automobile defrosting and other fields. Among them, the electric heater with quartz tube as the core heating element has become one of the market mainstream choices due to its high thermal efficiency, fast heating speed, excellent high-temperature resistance and other characteristics. In the prior art, the quartz tube is usually fixed on the heater shell or metal substrate by metal supports, buckles or bolts. The electric heating wire inside the quartz tube generates heat after being electrified, and the target object is heated through infrared radiation or heat conduction of the quartz tube.

[0003] However, as a brittle material, the quartz tube has a significant difference in thermal expansion coefficient with the metal fixing part. During the start and stop of the electric heater, the quartz tube and the metal fixing part will expand and contract out of sync due to temperature changes, resulting in a large thermal stress between them, which causes the quartz tube to break. SUMMARY

[0004] In order to improve the problem that the quartz tube and the metal fixing part in the existing electric heater generate thermal stress due to the difference in thermal expansion coefficient, causing the quartz tube to be easily broken, the present application provides an electric heater.

[0005] The electric heater provided by the present application adopts the following technical scheme:

[0006] An electric heater comprises:

[0007] A metal sheet is arranged in an arc shape and comprises a receiving portion and an opening portion, wherein the opening portion is arranged opposite to a target object to be heated;

[0008] A quartz tube is arranged in the receiving portion, and an electric heating wire is arranged in the quartz tube, wherein the electric heating wire is used to convert electrical energy into heat energy;

[0009] A metal cotton mesh is arranged between the metal sheet and the quartz tube, and the metal cotton mesh is used to absorb thermal stress through elastic deformation to avoid rigid extrusion between the metal sheet and the quartz tube.

[0010] The metal sheet arranged in an arc shape can support and fix the quartz tube, the opening part can guide the output direction of heat to improve the heating efficiency, the quartz tube serves as a carrier of the electric heating wire, the electric heating wire can convert electric energy into heat energy, and the heat is transmitted through infrared radiation or heat conduction of the quartz tube, the metal cotton net is arranged between the metal sheet and the quartz tube, and the metal cotton net can absorb thermal stress generated by the difference in thermal expansion coefficients of the metal sheet and the quartz tube through elastic deformation, so that rigid extrusion between the metal sheet and the quartz tube is avoided, and the problem that the quartz tube is easily broken due to thermal stress generated by the difference in thermal expansion coefficients between the quartz tube and the metal fixing part in the existing electric heater is solved.

[0011] Preferably, the metal cotton net comprises a frame and metal wires, the frame is fixedly connected with the metal sheet, and the metal wires are wound on the frame to form a three-dimensional porous cotton-like structure.

[0012] Through the above technical scheme, the frame can be a carrier of the metal wires and limit the position of the metal wires, the metal wires are wound on the frame to form a three-dimensional porous cotton-like structure, the flexibility of the metal wires and the compressibility of the porous structure are utilized to enhance the elastic deformation capacity, and the three-dimensional porous cotton-like structure formed by the metal wires can adapt to the surface profile of the quartz tube and the metal sheet, increase the contact area, and make the stress distribution more uniform.

[0013] Preferably, the frame is formed by welding a plurality of metal strips, the plurality of metal strips are all nickel-based alloy strips, the diameters of the plurality of metal strips are 0.07mm-0.09mm, the metal wires are nickel-based soft alloy wires, the diameters of the metal wires are 0.05mm-0.10mm, and the metal wires are wound on the frame.

[0014] Through the above technical scheme, the nickel-based alloy has high temperature resistance, so that the frame and the metal wires can withstand the high temperature environment of the quartz tube during work, the frame not only provides stable support for the metal wires, but also can absorb part of the thermal stress through slight deformation, the metal wires are formed by cross winding, the contact area with the quartz tube is increased, the thermal stress is more uniformly dispersed, the difference in thermal expansion and contraction between the metal sheet and the quartz tube is adapted, and the risk of rupture of the quartz tube caused by rigid extrusion is avoided.

[0015] Preferably, the surface of the frame is sandblasted and roughened.

[0016] By adopting the technical scheme, the sand blasting process forms rough texture on the surface of the frame, increases the micro concave-convex degree of the surface, the rough surface can significantly increase the friction between the metal wire and the frame, prevents the metal wire from slipping or loosening in the process of long-term vibration or thermal expansion and cold contraction, ensures the morphological stability of the three-dimensional porous cotton-like structure, the concave-convex surface changes the contact between the metal wire and the frame from "line contact" to "point-surface combination", disperses the local stress of the winding point, and avoids the breakage of the metal wire due to excessive stress on a single point.

[0017] Preferably, the metal wire is wound around the frame in a random spiral manner, and the winding density is 3-5 turns per square centimeter, so as to retain 75%-80% of the porosity.

[0018] By adopting the technical scheme, the irregular spiral path winding forms a disordered three-dimensional network structure of the metal wire on the frame, and the winding density of 3-5 turns per square centimeter ensures that the metal wire sufficiently covers the frame while avoiding excessive density to increase rigidity, so that the metal cotton net can absorb stress through the bending deformation of the metal wire and provide support through the compression of the pores when being pressed, and avoids the protection failure caused by being too soft.

[0019] Preferably, the metal sheet, the quartz tube and the metal cotton net are provided with a plurality of metal sheets, the metal cotton net extends to both sides, and the part of the metal cotton net extending to both sides is used for elastically hooking with the adjacent metal cotton net, so as to strengthen the connection strength of the plurality of metal sheets.

[0020] By adopting the technical scheme, the part of the metal cotton net extending to both sides forms a non-rigid hooking with the adjacent metal cotton net through the flexibility of the metal cotton net, such as winding, lap joint or micro hook structure, realizes the elastic splicing of the plurality of metal cotton nets, and thus the connection strength of the plurality of metal sheets is improved, the hooking structure disperses the relative displacement stress of the adjacent metal sheets through the elastic tension of the metal wire, avoids the breakage of single-point connection, a plurality of hooking structures cooperates to absorb the local vibration or deformation by the overall structure, and the impact resistance of the system is improved.

[0021] Preferably, the two sides of the metal sheet are respectively provided with an arc-shaped part and a protruding part, the arc-shaped part is used for accommodating the protruding part of the adjacent metal sheet, and the protruding part is used for being inserted into the arc-shaped part of the adjacent metal sheet.

[0022] By adopting the technical scheme, the concave-convex matching between the metal sheets realizes the physical embedding of the adjacent metal sheets, forms a mechanical interlocking similar to a mortise and tenon structure, and limits the position of the quartz tube.

[0023] Preferably, the connector is used for electrically connecting with the electric heating wire, the connector is provided with a plurality of connectors, and the plurality of connectors are used for sequentially connecting the plurality of electric heating wires in series.

[0024] By adopting the technical scheme, the connector is a physical interface of the heating wire, and mechanical fixation and current conduction between the heating wires are realized through the conductive contact; the plurality of connectors form a single path circuit in a series connection mode, so that the current flows through each heating wire in turn, and finally the heating of the electric heater is realized.

[0025] Preferably, the skin is used to wrap the plurality of metal sheets to limit the relative position of the plurality of metal sheets.

[0026] By adopting the technical scheme, the skin can wrap the plurality of metal sheets to limit the position of the metal sheets, avoid the sliding or falling of the metal sheets, and the skin can also play a heat insulation role to a certain extent.

[0027] Preferably, the junction box is fixedly connected with the skin, and the junction box is used to be electrically connected with the power supply and the connector to provide electric energy for the heating wire.

[0028] By adopting the technical scheme, the junction box is a transfer interface of the external power supply and the connector, can input the current into the connector, so that the heating wire can obtain electric energy and heat up.

[0029] In summary, the present application has at least one of the following beneficial technical effects:

[0030] 1. The arc-shaped metal sheet can support and fix the quartz tube, the opening part can guide the output direction of heat to improve the heating efficiency, the quartz tube serves as a carrier of the heating wire and contains the heating wire, the heating wire can convert electric energy into heat energy, and the heat is transferred through infrared radiation or heat conduction of the quartz tube, the metal cotton net is arranged between the metal sheet and the quartz tube, and the thermal stress generated by the difference in thermal expansion coefficients between the metal sheet and the quartz tube is absorbed through elastic deformation of the metal cotton net, so that the rigid extrusion between the metal sheet and the quartz tube is avoided, and the problem that the quartz tube is easily broken due to the thermal stress generated by the difference in thermal expansion coefficients between the quartz tube and the metal fixing part in the existing electric heater is solved.

[0031] 2. The frame can be a carrier of the metal wire and limit the position of the metal wire, the metal wire is wound on the frame to form a three-dimensional porous cotton-like structure, the flexibility of the metal wire and the compressibility of the porous structure are utilized to enhance the overall elastic deformation capacity, and the three-dimensional porous cotton-like structure formed by the metal wire can adapt to the surface profile of the quartz tube and the metal sheet, increase the contact area, and make the stress distribution more uniform.

[0032] 3. The nickel-based alloy has high temperature resistance, so that the frame and the wire can withstand the high temperature environment of the quartz tube during operation. The frame not only provides stable support for the wire, but also can assist in absorbing part of the thermal stress through slight deformation. The wire is formed by the cross winding of the wire, which increases the contact area with the quartz tube and makes the thermal stress more uniform. It can adapt to the difference between the metal sheet and the quartz tube in thermal expansion and contraction, and avoid the risk of rupture of the quartz tube caused by rigid extrusion. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a structural schematic diagram of an electric heater in the embodiment of the present application;

[0034] Figure 2 is a structural schematic diagram of a metal sheet in the embodiment of the present application;

[0035] Figure 3 is a connection structure schematic diagram of a metal sheet and a metal cotton net in the embodiment of the present application;

[0036] Figure 4 is a structural schematic diagram of a metal cotton net in the embodiment of the present application;

[0037] Figure 5 is a structural schematic diagram of a frame in the embodiment of the present application;

[0038] Figure 6 is a structural schematic diagram of the actual installation of a quartz tube in the embodiment of the present application.

[0039] Reference signs: 1, metal sheet; 11, containing part; 12, opening part; 13, arc-shaped part; 14, protruding part; 2, quartz tube; 3, electric heating wire; 4, metal cotton net; 41, frame; 42, wire; 5, connector; 6, skin; 7, junction box. DETAILED DESCRIPTION

[0040] The following will be described in detail in combination with the accompanying Figures 1-6 The present application is further described in detail.

[0041] The embodiment of the present application discloses an electric heater. Referring to Figure 1 and Figure 2 , the electric heater comprises a metal sheet 1, a quartz tube 2, a metal cotton net 4, a skin 6 and a junction box 7.

[0042] As shown in Figure 1 and Figure 2 , the metal sheet 1 is arc-shaped, the metal sheet 1 comprises a containing part 11 and an opening part 12, the opening part 12 is arranged opposite to the object to be heated, the arc-shaped metal sheet 1 can support and fix the quartz tube 2, the opening part 12 can guide the output direction of heat towards the object to be heated, thereby improving the heating efficiency.

[0043] In the embodiment of the present application, the metal sheet 1 is provided with a plurality of arc-shaped portions 13 and protruding portions 14 on both sides of each metal sheet 1, the arc-shaped portion 13 is used to accommodate the protruding portion 14 of the adjacent metal sheet 1, the protruding portion 14 is used to be inserted into the arc-shaped portion 13 of the adjacent metal sheet 1, the concave-convex matching between the metal sheets 1 realizes the physical fitting of the adjacent metal sheets 1, forms a mechanical interlocking similar to the mortise and tenon structure, and limits the position of the quartz tube 2.

[0044] As shown in Figure 3 , the quartz tube 2 is arranged in the accommodating portion 11, the quartz tube 2 is provided with an electric heating wire 3, the electric heating wire 3 is used to convert electrical energy into heat energy, the quartz tube 2 serves as a carrier to accommodate the electric heating wire 3, the electric heating wire 3 can convert electrical energy into heat energy, and the heat is transmitted through infrared radiation or heat conduction of the quartz tube 2; for example, the quartz tube 2 is provided with a plurality of quartz tubes 2, each quartz tube 2 is arranged in the accommodating portion 11 of the corresponding metal sheet 1, and a gap is arranged between each quartz tube 2 and the corresponding metal sheet 1.

[0045] As shown in Figure 3 and Figure 4 , the metal cotton net 4 is provided with a plurality of metal cotton nets 4, each metal cotton net 4 is arranged between the corresponding metal sheet 1 and the corresponding quartz tube 2, the metal cotton net 4 absorbs the thermal stress generated by the difference in thermal expansion coefficient between the metal sheet 1 and the quartz tube 2 through elastic deformation of itself, so as to avoid rigid extrusion between the corresponding metal sheet 1 and the corresponding quartz tube 2, and improve the problem that in the existing electric heater, the quartz tube 2 and the metal fixed part generate thermal stress due to the difference in thermal expansion coefficient, which causes the quartz tube 2 to be easily broken.

[0046] In the embodiment of the present application, the metal cotton net 4 includes a frame 41 and metal wires 42, the frame 41 is extended and bent, and finally fixedly connected with the side wall of the corresponding metal sheet 1, and the metal wires 42 are wound on the frame 41 to form a three-dimensional porous cotton-like structure; the frame 41 can provide a carrier for the metal wires 42 and limit the position of the metal wires 42, the metal wires 42 are wound on the frame 41 to form a three-dimensional porous cotton-like structure, the flexibility of the metal wires 42 and the compressibility of the porous structure are utilized to enhance the overall elastic deformation capability, and the three-dimensional porous cotton-like structure formed by the metal wires 42 can adapt to the surface profile of the quartz tube 2 and the metal sheet 1, increase the contact area, and make the stress distribution more uniform.

[0047] For example, please refer to Figure 5In the embodiment of the present application, the frame 41 is formed by welding a plurality of metal strips, each of which is a nickel-based alloy strip with a diameter of 0.07mm-0.09mm, and the metal wire 42 is a nickel-based soft alloy wire with a diameter of 0.05mm-0.10mm, which is wound around the frame 41. The nickel-based alloy has high temperature resistance, so that the frame 41 and the metal wire 42 can withstand the high temperature environment during the operation of the quartz tube 2. The frame 41 not only provides stable support for the metal wire 42, but also helps to absorb part of the thermal stress through slight deformation. The metal wire 42 is formed by crossing and winding the metal wire 42, which increases the contact area with the quartz tube 2 and makes the thermal stress more evenly distributed, so as to adapt to the difference in thermal expansion and contraction between the metal sheet 1 and the quartz tube 2 and avoid the risk of rupture of the quartz tube 2 caused by rigid extrusion.

[0048] For example, in the embodiment of the present application, the surface of the frame 41 is sandblasted to form a rough texture on the surface of the frame 41, which increases the micro concave-convex degree of the surface. The rough surface can significantly increase the friction between the metal wire 42 and the frame 41, prevent the metal wire 42 from slipping or loosening during long-term vibration or thermal expansion and contraction, ensure the stability of the three-dimensional porous cotton-like structure, and change the linear contact between the metal wire 42 and the frame 41 to point-surface contact, so as to disperse the local stress of the winding point and avoid the breakage of the metal wire 42 due to excessive stress on a single point.

[0049] For example, in the embodiment of the present application, the metal wire 42 is wound around the frame 41 in a random spiral manner with a winding density of 3-5 turns per square centimeter to retain 75%-80% porosity. The irregular spiral path winding forms a disordered three-dimensional network structure of the metal wire 42 on the frame 41. The winding density of 3-5 turns per square centimeter ensures that the metal wire 42 covers the frame 41 sufficiently while avoiding excessive density to increase rigidity, so that the metal cotton net 4 can absorb stress through the bending deformation of the metal wire 42 and provide support through the compression of the pores when under pressure, thereby avoiding the failure of protection caused by excessive softness.

[0050] It should be noted that, for a better understanding of the present application, reference can be made to Figure 3 and Figure 6In the embodiment of the present application, each metal cotton net 4 extends to both sides, and the portions of the metal cotton net 4 extending to both sides are used to elastically hook with the adjacent metal cotton net 4 to strengthen the connection strength of the plurality of metal sheets 1; the portions of the metal cotton net 4 extending to both sides form a non-rigid hooking with the adjacent metal cotton net 4 through the flexibility of the metal cotton net 4, and the plurality of metal cotton nets 4 are elastically spliced through a structure including but not limited to winding, overlapping or micro-hooking, so as to improve the connection strength of the plurality of metal sheets 1, the hooking structure disperses the relative displacement stress of the adjacent metal sheets 1 through the elastic tension of the metal wire 42, avoids the fracture of single-point connection, and the multiple groups of hooking cooperates to absorb the local vibration or deformation by the overall structure, thereby improving the impact resistance of the system; and the plurality of metal cotton nets 4 after being connected can play a role in blocking the flow of heat between the metal sheets 1 and the quartz tube 2 to a certain extent, thereby reducing the heat loss and improving the heating efficiency.

[0051] As shown in Figure 1 , the connector 5 is used for electrical connection with the heating wire 3, and a plurality of connectors 5 are provided, and the plurality of connectors 5 are used to sequentially connect the plurality of heating wires 3 in series; the connector 5 serves as a physical interface of the heating wire 3, and realizes mechanical fixation and current conduction between the heating wires 3 through conductive contacts; the plurality of connectors 5 form a single-path circuit in a sequential series connection mode, so that the current flows through each heating wire 3 in sequence, and finally realizes the heating of the electric heater; for example, the connector 5 includes but is not limited to a 560B-BULK direct plug-in connector or an MSTB-3030433 plug-in connector.

[0052] As shown in Figure 1 , the skin 6 covers the side of the plurality of metal sheets 1 away from the object to be heated, and the skin 6 can wrap the plurality of metal sheets 1, limit the position of the metal sheets 1, avoid the sliding or falling of the metal sheets 1, and also play a role in heat insulation to a certain extent; the skin 6 includes but is not limited to a silica gel cloth, a fluororubber cloth or a composite cloth composed of multiple layers of silica gel / fluorine rubber cloth, glass fiber cloth, stainless steel wire mesh, thermal insulation cotton and the like; for example, the skin 6 is sealed by a structure or component including but not limited to a bolt or a clamp.

[0053] As shown in Figure 1 , the junction box 7 is fixedly connected with the skin 6, and the junction box 7 is electrically connected with the power supply and the connector 5 through the wire to provide electric energy for the heating wire 3; the junction box 7 serves as a transfer interface of the external power supply and the connector 5, and can input the current into the connector 5, so that the heating wire 3 can obtain electric energy and make the heating wire 3 heat; for example, the junction box 7 includes but is not limited to an XLCF 8.25-09-B1 connector or an HBR2-1 connector.

[0054] The above are all preferred embodiments of the present application, and do not limit the protection scope of the present application, so that: all equivalent changes made according to the structure, shape, principle of the present application should be covered in the protection scope of the present application.

Claims

1. An electric heater, characterized by, The utility model relates to a metal sheet (1) is arranged in arc shape, including accommodating part (11) and opening part (12), opening part (12) is arranged opposite with the object to be heated, quartz tube (2) is arranged in accommodating part (11), the electric heating wire (3) is arranged in quartz tube (2), and the electric heating wire (3) is used to convert electric energy into heat energy, metal cotton net (4) is arranged between metal sheet (1) and quartz tube (2), and metal cotton net (4) is used to absorb thermal stress through elastic deformation to avoid rigid extrusion between metal sheet (1) and quartz tube (2), metal cotton net (4) includes frame (41) and metal wire (42), frame (41) is fixedly connected with metal sheet (1), and metal wire (42) is wound on frame (41) to form three-dimensional porous cotton-like structure, frame (41) is formed by welding several metal strips, several metal strips are all nickel-based alloy strips, the diameter of several metal strips is 0.07mm~0.09mm, metal wire (42) is nickel-based soft alloy wire, the diameter of metal wire (42) is 0.05mm~0.10mm, and metal wire (42) is wound on frame (41), metal wire (42) is wound on frame (41), and winding density is 3 turns every square centimeter~5 turns every square centimeter to keep 75%~80% porosity. The surface of the frame (41) is sandblasted and roughened. The metal sheet (1), the quartz tube (2) and the metal cotton net (4) are all provided with a plurality of metal cotton nets (4) extending to both sides, and the portions of the metal cotton nets (4) extending to both sides are used to elastically hook with adjacent metal cotton nets (4) to strengthen the connection strength of the plurality of metal sheets (1). The metal sheet (1) is provided with an arc-shaped portion (13) and a protruding portion (14) on both sides, respectively, the arc-shaped portion (13) is used to accommodate the protruding portion (14) of the adjacent metal sheet (1), and the protruding portion (14) is used to be inserted into the arc-shaped portion (13) of the adjacent metal sheet (1). The utility model also includes a connector (5) for electrically connecting with the electric heating wire (3), the connector (5) is provided with a plurality of connectors (5) for sequentially connecting a plurality of electric heating wires (3) in series. The utility model also includes a skin (6) for wrapping a plurality of metal sheets (1) to limit the relative position of the plurality of metal sheets (1). The utility model also includes a junction box (7) fixedly connected with the skin (6), the junction box (7) is used for electrically connecting with a power supply and the connector (5) to provide electric energy for the electric heating wire (3).

2. The electric heater of claim 1, wherein: ​ 3. The electric heater of claim 1, wherein: ​ 4. The electric heater of claim 3, wherein: ​ 5. The electric heater of claim 1, wherein: ​ 6. The electric heater of claim 5, wherein: ​ 7. The electric heater of claim 6, wherein: ​

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