Method for the interior metal-coating of glass tubes, especially for solar collectors

A method for the interior metal-coating of a glass tube, with the metal-coated surface being a cylindrical shell, with the following features:

• 2.1 the interior surface of the glass tube is wetted with a sensitizer solution;
• 2.2 optionally, any excess of sensitizer solution is removed from the interior space of the glass tube;
• 2.3 the interior surface of the glass tube is wetted with a mirror-coating solution;
• 2.4 optionally, any excess of mirror-coating solution is removed from the interior space of the glass tube;
• 2.5 the glass tube is brought to the horizontal position;
• 2.6 the two ends of the glass tube are closed off;
• 2.7 an etching solution for the partial removal of mirror-coating solution is introduced into the interior space of the glass tube in such a quantity that the interior space is filled only partly;
• 2.8 the etching solution is removed again from the interior space of the glass tube after a certain dwell time.

A method for the interior metal-coating of a glass tube, with the metal-coated surface being a cylindrical shell, having the following features:

• 4.1 the interior surface of the glass tube is wetted with a sensitizer solution;
• 4.2 optionally. any excess of sensitizer solution is removed from the interior space of the glass tube;
• 4.3 it is introduced into the part of the interior surface of the glass tube of a cylindrical shell which screens off the part of the glass tube which is not to be metal-coated;
• 4.4 the interior of the glass tube is filled with a mirror-coating solution;
• 4.5 optionally, any excess of mirror-coating solution is removed from the interior space of the glass tube.