Vacuum heat collecting tube

Abstract

The invention relates to the solar energy technical field, mainly related to a vacuum tube collector, comprising a metal pipe with the surface coated with a solar energy absorption coating layer, wherein a glass pipe is arranged outside the metal pipe; a vacuum layer is arranged between the glass pipe and the metal pipe, and getter can be put in the vacuum layer between the glass pipe and the metal pipe to maintain the vacuum degree; at least one end of the glass pipe is provided with a corrugated metal pipe, one end of the corrugated metal pipe is directly connected and sealed with the glass pipe, and the other end of the corrugated metal pipe is connected with the metal pipe; the joint between the corrugated metal pipe and the metal pipe and the corrugated metal pipe with the glass pipe are both provided with a shield to better protect the connecting joints. The corrugated pipe is made of material with the linear expansion coefficient between the 3 multiplied by 10<-6> / degrees to 5 multiplied by 10<-6> / degrees. The expansion coefficient is close to that of glass, thereby the corrugated pipe can be directly connected and sealed with the glass pipe arranged outside rather than connected through Kovar, thus reducing the number of the joints, improving the reliability of the pipes and better ensuring the vacuum degree.

Description

technical field [0001] The invention relates to the field of solar heat collecting tubes, and mainly relates to the field of solar heat collecting tubes with bellows. Background technique [0002] At present, domestic glass-metal straight-through solar vacuum heat collection tubes generally use metal tubes covered with solar absorbing coatings, metal tubes with glass tubes, and vacuum pumped between the glass tubes and metal tubes. In order to compensate the expansion of the glass tube smaller than the metal tube after the temperature rises, the bellows are often used to compensate for the expansion difference, and the bellows and the glass are connected by a Kovar alloy transition. [0003] The patent No. ZL 200620075347.3, which was retrieved and published on July 25, 2006, is called the patent of external expansion tank type solar vacuum heat collection tube. The heat collection tube includes a metal tube covered with a solar absorbing coating on the surface, and the meta...

AI Technical Summary

Problems solved by technology

This kind of heat collecting tube has two main disadvantages: one is that the glass tube and the corrugated tube that is also set outside the metal tube are sealed by Kovar alloy fusion, which increases the difficulty of operation; the other is the connection seam formed by the corrugated tube + Kovar alloy structure increased, increasing the difficulty of maintaining a vacuum

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