Dual-insulation high-efficiency safety electric water heater

Abstract

The invention relates to a dual-insulation high-efficiency safety electric water heater, belonging to the household apparatus. It comprises a water storage inner container inside the case; a bended electric heating tube inside the inner container; and a control circuit connecting the electric heating tube. Wherein, said electric heating tube is inserted in the heat conductive insulation sheath whose inner space matches the shape of electric heating tube; said heat conductive insulation sheath is through the metallic mounting end cap to be inserted into the metallic support tube whose shape matches the shape of said sheath; the end of said metallic support tube is sealed and welded with the metallic mounting end cap; and the outer screw of mounting end cap is sealed and screwed with the inner screw of the mounting hole of inner container. Compared to present technique, the invention can avoid change the former structure of water heater with lower cost, and it can form dual insulation outside the electric heating tube and at the connection with the inner container to avoid the electric leakage.

Description

technical field [0001] The invention relates to an electric water heater, in particular to an electric water heater whose safety is ensured by improving an insulating structure, and belongs to the technical field of household appliances. Background technique [0002] Electric water heaters are easy to use and significantly improve the quality of life, so they are widely used. The existing electric water heater is mainly composed of a control circuit on the housing, a water storage liner arranged in the shell, and an electric heating device installed in the liner. In order to facilitate installation and reduce its own power density, U-shaped electric heaters are commonly used in existing electric water heaters. [0003] In order to prevent leakage and ensure safe use, in addition to taking measures such as shell grounding and adding anti-electricity drainage tubes, designers mainly focus on the root cause of leakage-electric heating and propose various safety measures for se...

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Problems solved by technology

Yet, through in-depth and meticulous research, the applicant finds that the double insulation structure of the existing electric heater all has deficiencies.

[0004] For example, the utility model patent with the application number CN94218994.9 discloses a structure that fills between the heating element and the shell as an additional insulating heat transfer medium, so that the heater has a double insulation function. The inner tank will occupy a large space, and from the technical point of view, it is difficult to ensure that the filling is dense due to the inability to reduce the diameter, and if the filling material contains air, it is easy to cause the tube wall to burst during use

The double-insulated electric heater disclosed in CN97224405.0 covers a layer of continuous and uniform inorganic adhesive film on the outer surface of the ordinary metal electric heating tube, and then encapsulates it in the metal jacket without gaps, thereby forming a gap between the live parts and the outer metal sheath. Double leakage protection, this patent overcomes the shortcomings of the previous patent, but it is obviously only suitable for straight tubes, which is difficult to realize on U-shaped electric heating tubes, and because the thermal expansion coefficient of the inorganic adhesive film is quite different from that of metal tubes, it is easy to use after use. Cracks and loss of insulation

[0005] The double insulation structures disclosed in CN99234598.7 and CN99234808.0 Chinese patents are all composed of metal tubes and glass tubes coated with electric heating film.

[0006] Experiments have shown that the above-mentioned existing electric heating devices with double insulation structure cannot meet the upcoming GB4706. Realized on the heating device, so as to meet the requirements of reinforced insulation while still maintaining good heating performance

[0007] In addition, the above improvements have not proposed substantial improvements in the insulation connection between the electric heating device and the inner tank of the water heater, so even if a double insulation structure is adopted, there is still a weak link of leakage

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