Novel twisted electric heating tube

Abstract

A novel twisted electric heating tube comprises an electric heating outer tube and a resistance wire, wherein the cross section of the electric heating outer tube is of a non-circular structure, and the resistance wire is installed in the electric heating outer tube. At least one resistance wire arranged in the length direction of the electric heating outer tube is connected into the electric heating outer tube in a penetrating mode, and a leading-out rod used for communicating the resistance wire with an external circuit is installed at the end of the electric heating outer tube. The electric heating outer pipe is stressed, twisted and formed in the axial direction after being assembled; compared with the prior art, the electric heating outer pipe is twisted, so that the fluid flowing through the spiral flow channel on the surface of the electric heating pipe and the pipe wall generates continuous disturbance, the fluid can enter a turbulent flow state even under the condition of a low Reynolds number, and the fluid flows along the outer wall of the twisted pipe body in the longitudinal direction. Complex strong disturbance with the main characteristics of rotation and mixing is generated, the turbulence degree of fluid is enhanced, the heat exchange effect is greatly improved, the average temperature of the surface of the electric heating pipe is reduced, and generation of scale is slowed down.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of electric heating tube, specifically relates to a novel twist electric heating tube. BACKGROUND

[0002] Electric heating tube is a kind of electric appliance element that converts electric energy into heat energy, electric heating tube takes metal tube as shell, along the center axis of pipe inside evenly distributed spiral electric heating alloy wire, and its interstice is filled with compaction magnesium oxide sand with good insulating and heat conducting performance, the both ends of pipe mouth are sealed with waterproof material, this kind of metal armoring electric heating element can heat air, metal mould and various liquids, common electric heating tube has fin electric heating tube, teflon electric heating tube, quartz electric heating tube and so on, because its price is cheap, convenient to use, easy to install, pollution-free, is widely used in various heating occasions.

[0003] Because the electric heating tube for heating water on the market is single in structure, low in heat transfer efficiency, and easy to scale on the surface of electric heating tube after being used for a period of time, heat efficiency is reduced, electric heating tube is corroded quickly, which affects the service life of electric heating tube.

[0004] Chinese patent number CN201922198676.7 discloses an infrared radiation electric heating tube, which comprises an electric heating sheet, the electric heating sheet is twisted into a spiral shape, and electrode sheets are integrally formed at the two ends of the electric heating sheet, and insulating ceramic sleeves are arranged on the electrode sheets.

[0005] The electric heating sheet inside the electric heating tube disclosed in the above is in spiral shape, the overall appearance structure of the electric heating tube does not change, heating is carried out under the action of the spiral-shaped electric heating sheet, but the above-mentioned infrared radiation heating tube can only be used for heating air. UTILITY MODEL CONTENTS

[0006] The utility model discloses in order to overcome the defects in the prior art, provide a new twist electric heating tube with high heat exchange efficiency, reduce the average temperature of pipe surface and slow down the production of scale.

[0007] In order to realize the above-mentioned utility model purposes, the utility model adopts the following technical scheme: a new twist electric heating tube, including the electric heating outer tube of cross section is non-round structure and the electric resistance wire installed in the electric heating outer tube, the electric heating outer tube is inserted with at least one electric resistance wire along the length direction of electric heating outer tube, and the electric heating outer tube end installs the lead-out rod for being connected with the external circuit of electric resistance wire, the electric heating outer tube is twisted into shape along the axial direction after assembly.

[0008] As a preferred scheme of the utility model, the cross section of the electric heating outer tube is flat tube or oval structure.

[0009] As a preferred scheme of the utility model, the ratio of long axis and short axis of the pipe cross section of the electric heating outer tube is 1.5~10.

[0010] As a preferred scheme of the utility model, the electric heating outer tube is in helical structure along the axial direction of the electric heating outer tube.

[0011] As a preferred scheme of the utility model, the ratio of the pitch of the electric heating outer tube to the long axis is 2-15.

[0012] As a preferred scheme of the utility model, the cross-sectional area of any section of the electric heating outer tube is the same.

[0013] As a preferred scheme of the utility model, a plurality of resistance wires are arranged in the electric heating outer tube, and the electric heating outer tube is filled with an insulating heat-conducting layer to ensure that the plurality of resistance wires do not interfere with each other.

[0014] As a preferred scheme of the utility model, the ratio of the pitch of the electric heating outer tube to the long axis is linearly or nonlinearly distributed along the length direction of the electric heating outer tube.

[0015] As a preferred scheme of the utility model, the end of the electric heating outer tube is provided with a sealing structure for sealing the pipe opening of the electric heating outer tube, and the lead-out rod is arranged through the sealing structure.

[0016] Compared with the prior art, the utility model has the beneficial effects that: by twisting the electric heating outer tube, continuous disturbance is generated between the fluid flowing through the helical flow channel on the surface of the electric heating tube and the tube wall, so that the fluid can enter the turbulent flow state even at a lower Reynolds number, and the fluid generates complex strong disturbance mainly characterized by rotation and mixing while flowing longitudinally along the outer wall of the twisted tube body, the turbulent flow degree of the fluid is enhanced, the heat exchange effect is greatly improved, the average temperature of the surface of the electric heating tube is reduced, and the generation of scale is slowed down. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is the schematic view of the utility model;

[0018] Figure 2 It is the sectional view of the utility model;

[0019] Figure 3 It is the cross-sectional schematic view of the utility model;

[0020] Figure 4 It is the use schematic view of the electric heating tube;

[0021] Figure 5 It is the velocity nephogram of water flowing through the outer wall of the round tube electric heating tube;

[0022] Figure 6 It is the velocity nephogram of water flowing through the outer wall of the twisted electric heating tube of the utility model;

[0023] Figure 7is the outlet temperature distribution nephogram of water flowing through the twisted electric heating pipe of the utility model;

[0024] Figure 8 is the outlet temperature distribution nephogram of water flowing through the twisted electric heating pipe of the utility model;

[0025] Figure 9 is the surface temperature distribution nephogram of the twisted electric heating pipe of the utility model;

[0026] Figure 10 is the surface temperature distribution nephogram of the twisted electric heating pipe of the utility model;

[0027] The drawing reference: lead bar 1, sealing structure 2, insulating heat conduction layer 3, electric heating outer tube 4, resistance wire 5, water pipe 6, spiral flow channel 7. DETAILED DESCRIPTION

[0028] The utility model embodiment is explained in detail below with reference to the drawings.

[0029] As Figures 1-10 shown, a novel twisted electric heating pipe, including electric heating outer tube 4 and install in electric heating outer tube 4's resistance wire 5, electric heating outer tube 4 is inserted with at least one resistance wire 5 along the length direction of electric heating outer tube 4, and the end of electric heating outer tube 4 is installed with the lead bar 1 for being connected with the external circuit of resistance wire 5, electric heating outer tube 4 is stressed and twisted along the axial direction of electric heating outer tube 4, and the radial cross-sectional area of twisted electric heating outer tube 4 is same.

[0030] The number of resistance wire 5 of electric heating outer tube 4 is set according to actual needs, and the number of lead bar 1 is also set according to the number of resistance wire 5, the lead bar 1 is used to be connected with the external circuit, and the resistance wire 5 is connected with the external circuit under the action of lead bar 1, so that the resistance wire 5 generates heat under the condition of being electrified.

[0031] Electric heating outer tube 4 is hollow structure, at least one resistance wire 5 is installed in electric heating outer tube 4, the hollow structure of electric heating outer tube 4 facilitates the installation of resistance wire 5 in electric heating outer tube 4, the length of resistance wire 5 is less than the length of electric heating outer tube 4, and both ends of resistance wire 5 are located in electric heating outer tube 4, to ensure that all the heat generated by resistance wire 5 is located in electric heating outer tube 4.

[0032] Electric heating outer tube 4 is inserted with several resistance wires 5, and electric heating outer tube 4 is filled with insulating heat conduction layer 3 to ensure that several resistance wires 5 do not interfere with each other.

[0033] The insulating heat conduction layer 3 is magnesium oxide powder, which can realize the external wrapping of resistance wire 5 under the action of magnesium oxide powder, so as to ensure that resistance wire 5 is always in a relatively stable state, and magnesium oxide powder prevents the connection between adjacent resistance wires 5 under the insulation effect, to ensure the separate heating effect of multiple resistance wires 5.

[0034] Meanwhile, the magnesium oxide powder transmits the heat generated by the resistance wire 5 to the electric heating outer tube 4 under the action of heat conduction, and the filled magnesium oxide powder realizes uniform heating of the electric heating outer tube 4.

[0035] The electric heating outer tube 4 is provided with a plurality of lead-out rods 1 corresponding to the number of the resistance wires 5 at the end thereof, and the lead-out rods 1 can be arranged at one end of the electric heating outer tube 4 or at opposite ends of the electric heating outer tube 4, and can be arranged according to the electric heating outer tube 4 of different structures. When the electric heating outer tube 4 needs to be powered at one end, the lead-out rods 1 are arranged at one end of the electric heating outer tube 4, and the number of the lead-out rods 1 corresponds to the number of the resistance wires 5.

[0036] The electric heating outer tube 4 is provided with the lead-out rods 1 connected with the resistance wires 5 at both ends thereof, and the lead-out rods 1 at both ends of the electric heating outer tube 4 are respectively connected to opposite ends of the resistance wires 5, so that both ends of the resistance wires 5 are in a powered state, and the electric heating outer tube 4 is provided with the lead-out rods 1 corresponding to the number of the resistance wires 5 at both ends thereof.

[0037] The electric heating outer tube 4 is provided with a sealing structure 2 for sealing the pipe opening of the electric heating outer tube 4 at the end thereof, and the lead-out rods 1 pass through the sealing structure 2, and the sealing structure 2 is silica gel for sealing the pipe opening of the electric heating outer tube 4.

[0038] The electric heating outer tube 4 has a non-circular structure in cross section, and the electric heating outer tube 4 has a spiral structure along the length direction of the electric heating outer tube 4.

[0039] In actual use, the electric heating outer tube 4 is initially in a non-circular structure, and then the resistance wires 5, the insulating and heat-conducting layer 3, the lead-out rods 1 and the sealing structure 2 are installed on the electric heating outer tube 4, and then the electric heating outer tube 4 is twisted and formed. According to the power requirement, the number of the resistance wires 5 in the electric heating outer tube 4 can be one, two or even more, and the length-to-short-axis ratio and the pitch of the electric heating outer tube 4 are adjusted according to the actual situation.

[0040] The electric heating outer tube 4 is twisted and formed in the axial direction after assembly, so that the resistance wires 5, the insulating and heat-conducting layer 3, the lead-out rods 1 and the sealing structure 2 are twisted synchronously in the twisting process of the electric heating outer tube 4.

[0041] Preferably, the cross-sectional shape of the electric heating outer tube 4 can be a flat tube or an elliptical structure, and the length-to-short-axis ratio A / B of the pipe cross section of the electric heating outer tube 4 is 1.5-10.

[0042] The electric heating outer tube 4 has a spiral structure along the axial direction of the electric heating outer tube 4, and the pitch-to-long-axis ratio S / A of the electric heating outer tube 4 is 2-15.

[0043] In use, the new twisted electric heating tube is usually installed in the water pipe 6, and the flow channel between the water pipe 6 and the new twisted electric heating tube forms a pipe channel, and the pipe channel forms a spiral flow channel 7 under the action of the outer wall of the new twisted electric heating tube.

[0044] As shown in Figures 5-8 , under the conditions of the same power, electric heating tube cross-sectional area, electric heating tube length, inlet mass flow, inlet water temperature, flow passage cross-sectional area, and flow passage length, the flow velocity and heat exchange effect of water flowing through the outer wall of the round tube electric heating tube and the twisted electric heating tube are simulated. The flow channel of the twisted electric heating tube is helical, and the fluid flows longitudinally while generating complex strong disturbances mainly characterized by rotation and mixing, thereby enhancing the turbulence degree of the fluid, that is, the fluid can enter the turbulent state even at a lower Reynolds number.

[0045] As shown in Figure 5 and Figure 6 , at a lower Reynolds number, compared with the round tube electric heating tube, the flow velocity of water flowing through the outer wall of the twisted electric heating tube changes more sharply, and a transverse secondary flow is generated. Therefore, the structural design of the twisted flat tube enhances the turbulence degree of the fluid. The longitudinal mixing of the fluid helps to fully exchange heat, thereby enhancing the heat exchange effect.

[0046] As shown in Figure 7 and Figure 8 , the distribution cloud diagrams of the outlet temperature of water flowing through the round tube and the twisted electric heating tube are shown, and it can be obviously seen that the outlet temperature distribution of the twisted flat tube is higher. According to statistics, the average outlet temperature of the twisted flat tube is 20.7% higher than that of the round tube.

[0047] As shown in Figure 9 and Figure 10 , the round tube electric heating tube and the twisted electric heating tube with the same power, heat exchange area, power density, and heating section length are designed, and simulation is carried out under the same fluid conditions, and the pipe surface temperature distribution cloud diagram is obtained, in which the average temperature of the surface of the twisted flat tube is 24.2% lower than that of the round tube. The lower the temperature, the less likely the scale is to be generated, and the enhanced turbulence effect of the twisted electric heating tube can play a scouring role, so that the scale is not easy to adhere.

[0048] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application; therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

[0049] Although the present application uses the terms: lead rod 1, sealing structure 2, insulating and heat-conducting layer 3, electric heating outer tube 4, resistance wire 5, water pipe 6, spiral flow channel 7, etc. more frequently in the description, it does not exclude the possibility of using other terms. The use of these terms is only for the convenience of describing and explaining the essence of the present application; any interpretation of them as an additional limitation is contrary to the spirit of the present application.

Claims

1. A new type of twisted electrothermal tube, characterized in that, The electric heating outer tube (4) has a non-circular cross-section, and the electric resistance wire (5) is installed in the electric heating outer tube (4); at least one electric resistance wire (5) is arranged along the length direction of the electric heating outer tube (4) and is connected to the external circuit through the lead-out rod (1) installed at the end of the electric heating outer tube (4); and the electric heating outer tube (4) is twisted and formed along the axial direction after assembly.

2. A new type of twisted electrothermal tube according to claim 1, characterized in that, The cross-section of the electric heating outer tube (4) is a flat tube or an elliptical structure.

3. A new type of twisted electrothermal tube according to claim 2, characterized in that, The ratio of the long axis to the short axis of the pipe cross-section of the electric heating outer tube (4) is 1.5-10.

4. A new type of twisted electrothermal tube according to claim 1, characterized in that, The electric heating outer tube (4) has a spiral structure along the axial direction of the electric heating outer tube (4).

5. A new type of twisted electrothermal tube according to claim 4, characterized in that, The ratio of the pitch to the long axis of the electric heating outer tube (4) is 2-15.

6. A new type of twisted electrothermal tube according to claim 4, characterized in that, The ratio of the pitch to the long axis of the electric heating outer tube (4) is linearly or nonlinearly distributed along the length direction of the electric heating outer tube (4).

7. A new type of twisted electrothermal tube according to claim 1, characterized in that, The cross-sectional area of any section of the electric heating outer tube (4) is the same.

8. A new type of twisted electrothermal tube according to claim 1, characterized in that, The electric heating outer tube (4) is filled with several electric resistance wires (5), and the electric heating outer tube (4) is filled with an insulating and heat-conducting layer (3) to ensure that the several electric resistance wires (5) do not interfere with each other.

9. A new type of twisted electrothermal tube according to claim 1, characterized in that, The end of the electric heating outer tube (4) is provided with a sealing structure (2) for sealing the pipe opening of the electric heating outer tube (4), and the lead-out rod (1) passes through the sealing structure (2).

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