Patent ID: 8302596

Claim:
A matched glass-to-metal connecting device for a vacuum tube collector for a solar energy collecting apparatus, the matched glass-to-metal connecting device comprising: a glass envelope consisting of a glass having a composition, in percent by weight on the basis of oxide content, consisting essentially of: B 2 O 3 19, Al 2 O 3 8, Na 2 O 2, K 2 O 2 3, BaO 3, LiF 1, SiO 2 balance to 100%; and a metal sleeve directly bonded to the glass envelope, wherein the metal sleeve has a thermal expansion coefficient of 4.89×10 −6 K −1 in the temperature range of 25° C. to 350° C. and the glass envelope has a thermal expansion coefficient that deviates from the metal sleeve's thermal expansion coefficient by no more than 4% in the temperature range of 25° C. to 350° C.; and an absorber tube positioned within the glass envelope extending through the glass-to-metal joint.