High performance single-ended heating element for steam generator
By employing multiple single-ended heating tubes and a magnesium core and magnesium powder structure in the steam generator, the power density and temperature gradient of the heating wire are reduced, solving the problem of heating wire damage caused by high power density and extending its service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHENJIANG DONGFANG ELECTRIC HEATING TECH
- Filing Date
- 2025-04-10
- Publication Date
- 2026-06-02
Smart Images
Figure CN224319540U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of heaters, and in particular to a heating element for a steam generator. Background Technology
[0002] Steam generators are primarily used in applications such as floor scrubbers to quickly heat water and produce steam. The steam generator housing contains a heating chamber, with an inlet and an outlet on the housing that communicate with the heating chamber. The heating element is located within the heating chamber. (See attached image.) Figures 1-3 The common heating element structure shown is a double-ended heating tube folded in half and welded to the flange. The heating element is placed inside the heating chamber. The front section of the heating tube is at the same end as the water inlet, and the rear section of the heating tube is at the other end of the heating element, which is the same as the air outlet.
[0003] Due to the requirement for a small steam generator and the limited space within the heating chamber, the length of the heating tube is restricted, resulting in a high electrical density on the tube surface. During operation, the front section of the heating element is wetted by water, while the rear section, especially the tail end, is in a dry-burning state, sometimes reaching temperatures exceeding 1000℃. Under prolonged use, the heating wire at the tail end of the tube, subjected to high temperatures and constant thermal shocks, becomes unsustainable due to the material's own limitations, potentially causing the heating element to fail prematurely. Utility Model Content
[0004] Purpose of the utility model: In view of the above problems, the purpose of this utility model is to provide a heating element for a steam generator that, under the conditions of equal length and power of the heating tube, reduces the electric power density on the surface of the tube and the electric power density on the surface of the heating wire inside the tube, thereby reducing the temperature of the heating wire and improving its service life.
[0005] Technical solution: A high-performance single-end heating element for a steam generator, comprising more than one single-end heating tube, wherein two lead-out rods are arranged inside the outer tube of the single-end heating tube, the front ends of the lead-out rods extending from the front end of the outer tube, the front end of the outer tube being fixed to a flange, and the front ends of the lead-out rods being located outside the flange.
[0006] Furthermore, the heating wire is sleeved on the magnesium core inside the outer tube; based on the existing heating cavity size inside the steam generator shell, the outer diameter of the outer tube can be set to D1 as 6.6-10mm, and the heating body has more than one single-end heating tube, which increases the tube surface area and reduces the surface electric power density. The outer diameter of the heating wire D2 is 3.5-6.5mm, and the distance between the outer diameter of the heating wire D2 and the inner diameter of the outer tube is no more than 2mm. The temperature gradient between the heating wire and the tube surface is smaller, and the heat can be better dissipated to the tube surface, resulting in better heat dissipation.
[0007] Ideally, the outer diameter D1 of the outer tube is 8 mm and the outer diameter D2 of the heating wire is 5 mm.
[0008] Furthermore, magnesium powder is filled between the magnesium core and the outer tube, and the magnesium powder, together with the magnesium core, has a better thermal conductivity.
[0009] Furthermore, based on the existing heating chamber dimensions inside the steam generator housing, the effective heating length of the outer tube can be set to 30–150 mm.
[0010] Furthermore, each of the single-ended heating tubes is connected in series or in parallel with the front end of the lead-out rod.
[0011] Furthermore, each of the single-ended heating tubes is arranged in parallel horizontally, and the outer tubes of adjacent single-ended heating tubes are welded together for fixation.
[0012] Furthermore, the front end of the outer tube is welded and fixed to the flange.
[0013] Furthermore, the outer tube is a stainless steel tube; the positive electrode lead-out rod and the negative electrode lead-out rod are stainless steel rods or nickel rods.
[0014] Furthermore, the heating wire is a nickel-chromium wire; the magnesium core is a magnesium oxide core; and the density of the magnesium core is not less than 3.3 g / cm³. 3 .
[0015] Beneficial effects: The advantages of this utility model are: under the premise of the existing steam generator shell structure, a heating element with a single-end heating tube is designed to replace the heating element with a double-end heating tube. It mainly adopts more than one single-end heating tube and increases the outer diameter of the single-end heating tube, so as to achieve the same power of the heating element and reduce the electric power density on the tube surface and the electric power density on the surface of the heating wire, thereby reducing the temperature of the heating wire. The maximum temperature of the heating element tube surface has been successfully reduced from more than 1000℃ to 800℃, which greatly improves the performance and service life of the heating element. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of an existing heating element with double-ended heating tubes;
[0017] Figure 2 for Figure 1 Top view;
[0018] Figure 3 for Figure 2 The left view;
[0019] Figure 4 This is a schematic diagram of the structure of the heating element of this utility model;
[0020] Figure 5 for Figure 4 Top view;
[0021] Figure 6 for Figure 5The left view;
[0022] Figure 7 This is a schematic diagram of a four-wire connection between two single-ended heating tubes;
[0023] Figure 8 This is a schematic diagram showing the series connection between two single-ended heating tubes;
[0024] Figure 9 This is a schematic diagram of two single-ended heating tubes connected in parallel. Detailed Implementation
[0025] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.
[0026] A high-performance single-end heating element for a steam generator, as shown in the attached image. Figures 4-6 As shown, it includes a single-end heating tube 1 and a flange 2. There is more than one single-end heating tube 1, such as the two single-end heating tubes 1 shown in the attached figure. The front end of the single-end heating tube 1 is fixed to the flange 2.
[0027] The single-ended heating tube 1 includes an outer tube 11, lead-out rods 12, heating wire 13, magnesium core 14, and magnesium powder 15. Two lead-out rods 12 are arranged within the magnesium core 14, with their front ends extending from the front end of the magnesium core 14. The heating wire 13 is wrapped around the outer circumference of the magnesium core 14 along its length. The tail end of the outer tube 11 is closed. The lead-out rods 12, heating wire 13, and magnesium core 14 are placed together inside the outer tube 11 from its front end, with the front end of the lead-out rods 12 extending from the front end of the outer tube 11. The space between the magnesium core 14 and the outer tube 11 is filled with magnesium powder 15 and compacted by tube shrinking, after which the front end of the outer tube 11 is closed. The single-ended heating tube 1 is fixed to the flange 2 via the front end of the outer tube 11. If fixed using welding methods such as nickel welding, silver welding, laser welding, or argon arc welding, the front end of the lead-out rods 12 is located on the outer side 21 of the flange 2.
[0028] Two single-ended heating tubes 1 are arranged horizontally in parallel. The two single-ended heating tubes do not necessarily need to be fixed together, or adjacent single-ended heating tubes 1 can be further fixed together by an outer tube 11, such as by nickel soldering, silver soldering, or laser welding. The two single-ended heating tubes 1 are connected by the front end of the lead-out rod 12 as shown in the attached figure. Figure 7 The four-wire connection shown, or as attached Figure 8 The series connections shown in (a) and (b), or as shown in the appendix Figure 9 The parallel connection is shown.
[0029] The outer tube 11 is made of stainless steel and its surface can be treated with nickel plating or other methods. The lead-out rod 12 is made of stainless steel or nickel. The heating wire 13 is made of nickel-chromium wire or similar high-temperature resistant heating wire. The magnesium core 14 is made of magnesium oxide, pressed under high pressure, with a density of not less than 3.3 g / cm³. 3 .
[0030] The heating element of this invention is used to replace the existing heating element with double-ended heating tubes. It is installed in the same steam generator housing. The goal is to achieve the same power output and reduce the electric power density on the tube surface and the electric power density on the heating wire surface. Due to the limitation of the heating cavity inside the steam generator housing, the heating tubes must maintain the same length.
[0031] Existing heating elements with double-ended heating tubes typically use an outer tube with an outer diameter of 6.6 mm and a heating wire with an outer diameter of 3 mm. The distance between the outer diameter of the heating wire and the inner diameter of the outer tube is generally more than 1.2 mm. The heating tube is filled with only magnesium powder and compacted, resulting in a density of only 3.0 g / cm³. 3 The heating element designed in this utility model for replacement uses two single-end heating tubes 1. The outer diameter D1 of the outer tube 11 is 6.6-10mm, the outer diameter D2 of the heating wire 13 is 3.5-6.5mm, the distance between the outer diameter D2 of the heating wire 13 and the inner diameter of the outer tube 11 is no more than 2mm, and the effective heating length of the outer tube 11 is 30-150mm.
[0032] The heating element of this invention primarily utilizes more than one single-ended heating tube. The outer diameter D1 of each single-ended heating tube is increased, for example, to 8mm. Using two single-ended heating tubes arranged in parallel increases the surface area of the heating element by approximately 24% and reduces the surface electrical density by approximately 13%, thus lowering the heating wire temperature. The heating wire outer diameter D2 reaches 5mm, providing better internal heat dissipation space, further reducing its temperature. The distance between the heating wire outer diameter D2 and the inner diameter of the outer tube in each single-ended heating tube is no more than 2mm, resulting in a smaller temperature gradient between the heating wire and the tube surface. This allows for better heat dissipation to the tube surface, leading to improved heat dissipation and a lower heating wire temperature. The magnesium core used in the single-ended heating tube has a density of no less than 3.3g / cm³. 3 In contrast, magnesium cores have better thermal conductivity, thus reducing the temperature of the heating wire. Overall, under the same power conditions, the maximum surface temperature of the heating element was successfully reduced from over 1000℃ to 800℃, significantly improving the performance and lifespan of the heating element.
Claims
1. A high-performance single-end heating element for a steam generator, characterized in that: It includes more than one single-ended heating tube (1), and two lead-out rods (12) are arranged inside the outer tube (11) of the single-ended heating tube (1). The front end of the lead-out rod (12) is led out from the front end of the outer tube (11). The front end of the outer tube (11) is fixed to the flange (2), and the front end of the lead-out rod (12) is located outside (21) of the flange (2).
2. The high-performance single-end heating element of a steam generator according to claim 1, characterized in that: The heating wire (13) is sleeved on the magnesium core (14) inside the outer tube (11); the outer diameter D1 of the outer tube (11) is 6.6 to 10 mm, the outer diameter D2 of the heating wire (13) is 3.5 to 6.5 mm, and the distance between the outer diameter D2 of the heating wire (13) and the inner diameter of the outer tube (11) is no more than 2 mm.
3. The high-performance single-end heating element of a steam generator according to claim 2, characterized in that: The outer diameter D1 of the outer tube (11) is 8 mm, and the outer diameter D2 of the heating wire (13) is 5 mm.
4. The high-performance single-end heating element of a steam generator according to claim 2, characterized in that: Magnesium powder (15) is filled between the magnesium core (14) and the outer tube (11).
5. The high-performance single-end heating element of a steam generator according to claim 1, characterized in that: The effective heating length of the outer tube (11) is 30-150 mm.
6. The high-performance single-end heating element of a steam generator according to claim 1, characterized in that: Each of the single-ended heating tubes (1) is connected in series or in parallel with the front end of the lead-out rod (12).
7. The high-performance single-end heating element of a steam generator according to claim 1, characterized in that: Each of the single-ended heating tubes (1) is arranged in parallel horizontally, and the outer tubes (11) are welded together to fix adjacent single-ended heating tubes (1).
8. The high-performance single-end heating element of a steam generator according to claim 1, characterized in that: The front end of the outer tube (11) is welded and fixed to the flange (2).
9. The high-performance single-end heating element of a steam generator according to claim 1, characterized in that: The outer tube (11) is a stainless steel tube; the lead-out rod (12) is a stainless steel rod or a nickel rod.
10. A high-performance single-end heating element for a steam generator according to claim 2, characterized in that: The heating wire (13) is a nickel-chromium wire; the magnesium core (14) is a magnesium oxide core; the density of the magnesium core (14) is not less than 3.3 g / cm³. 3 .