The invention relates to a sealed mechanical connection between glass and metal for receiver tubes used in solar plants of the type using a heat-transfer fluid, which uses a mechanical force in order to establish the seal between the inner metal tubes and the outer glass tubes, between which tubes a high vacuum is established in order to prevent heat losses. According to the invention, a flexible, deformable metal joint is used for the above-mentioned seal, which joint, when duly compressed, adapts to the corresponding surfaces of the tubes to be sealed, thereby establishing the seal between the respective tubes. In addition, the invention can include a continuous system for maintaining the necessary vacuum between both types of tubes.