Vacuum heat collecting tube

Abstract

The invention proposes a vacuum heat collecting tube; a water heating system is high in utilization rate and high in working reliability; multiple heat absorbing plates (4) are all arranged in an inner glass pipe (1); a closed end of a U-shaped water pipe (5) is arranged in the inner glass pipe (1); two opening ends of the U-shaped water pipe (5) are arranged outside the inner glass pipe (1); the U-shaped water pipe (5) is connected with the multiple heat absorbing plates (4); blanking caps (6) are arranged at the opening ends of the inner glass pipe (1); the heat absorbing plates (4) are metal plates; and a preparation method of the heat absorbing plates comprises the following steps: (1) metal plates are cleaned and dried; (2) the metal plates are annealed by 60-65 seconds at a temperature of 800-850 DEG C; and blue oxide layers are formed on the surfaces of the metal plates; and (3) tin oxide coating layers with thicknesses of 80-90 nm are sprayed on the surfaces of the metal pipes by using a metal atomization spraying deposition process.

Description

technical field [0001] The invention relates to the technical field of solar water heaters, in particular to a vacuum heat collecting tube for solar water heaters. Background technique [0002] Solar energy is a green energy in today's society. People can save more energy by using solar energy, so we should make good use of solar energy and play its due role. Solar water heaters are favored by people because of their use of solar energy, no pollution, convenient use, and low investment costs for long-term use, and they have been well developed. Among them, the vacuum heat collecting tube is one of the important parts of the solar water heater, and its thermal efficiency directly affects the performance of the solar water heater. [0003] Vacuum heat collecting tubes of the prior art such as figure 1 As shown, it includes an inner glass tube 101 and an outer glass tube 102; the outer wall of the inner glass tube 101 is coated with a heat-absorbing coating; the outer glass t...

AI Technical Summary

Problems solved by technology

The vacuum heat collecting tube with the above structure has the following disadvantages: due to the large amount of water stored in the inner glass tube, the temperature of the water in the tube rises slowly, and the hot water in the tube cannot be taken out completely, resulting in a low utilization rate of the hot water system; Water, if it is damaged during operation, the entire solar system will stop working, thus making its work less reliable

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