Method for the production of a glass-metal attachment

Method for the production of a glass-metal attachment for a solar receiver, the solar receiver comprising a glass tube having a diameter Dt with a thickness et and a metal ring with a diameter Da and a thickness ea, and wherein the glass tube comprises two ends, the method comprising the steps of:

• modifying the thickness et of the first end of the glass tube to a modified thickness em, the modified thickness em being greater than the thickness et of the first end of the tube, and
• attaching the metal ring with the first end of the glass tube.
• wherein the step of modifying the thickness em of the first end of the glass tube to a modified thickness em comprises the steps of:
• a) arranging the glass tube rotating about its longitudinal axis X-X′,
• b) heating a first end of the glass tube, wherein the heating of said first end is maintained until the metal ring is attached with the first end of the glass tube,
• c) positioning the first end of the glass tube along the longitudinal direction X-X′ between a first roller.Hand a second roller, wherein the first roller preferably comprises a first end having a diameter D1 and a length L1 and a second end having a diameter D2 and a length L2, the diameter D1 of the first endbeing smaller than the diameter D2 of the second end, with a step (e) being formed between both, and the second roller is a cylinder having a diameter D3 and a length L3 configured for being arranged separated from the first roller in its initial position.
• d) moving the second roller in the transverse direction Y-Y′, wherein Y-Y′ is substantially perpendicular to the longitudinal direction X-X′, until the first roller and the second roller come into contact,
• e) moving either the pair of rollers, or else the glass tube, and/or both along direction X-X′, such that the first end of the glass tube comes into contact with the pair of rollers and continues to move in direction X-X′ with the thickness er of the first end of the glass tube being modified until achieving the modified thickness em, the thickness em being greater than the thickness er of the glass tube, and wherein the step of attaching the metal ring (with the first end of the glass tube ( comprises the steps of:
• f) positioning at the first end of the glass tube diameter calibration means configured for modifying the diameter of the first end of the glass tube, and
• g) attaching the metal ring with the first end of the glass tube.