| 摘要 |
PURPOSE:To improve the manufacturing yield of the double vacuum tube type solar heat collecting tube by a method wherein the double tube is constituted by arranging an inner tube, closed at one end thereof and provided with a black film for absorbing the solar heat, into a glass straight tube, closed at one end thereof by lid member equipped with a small diametral air discharging tube, while the air discharging tube is cut under keeping the seal thereof after the air in the outer tube is discharged and the pressure thereof is reduced. CONSTITUTION:The outer tube 2 is formed by securing the bottom piece forming lid member 7, having the small diametral glass tube 6 for discharging air, to one end of the glass straight tube 2 for the outer so as to keep air tightness. The inner tube 10 is formed by forming the bottom section thereof at one end thereof by a grinding work while the black film for absorbing the solar heat is formed around the outer surface thereof. The inner tube 10 is arranged in the outer tube 2 and secured thereto to make the double tube. Next, the pressure of the air between the inner and outer tube 2, 10 is reduced through the air discharging tube 6. Subsequently, the air discharging tube 6 is cut by an electrical heat chip-off work at a position near the base thereof under keeping the seal. According to this method, the double vacuum tube may be manufactured simply without necessitating a skill therefor and the manufacturing yield thereof may be improved. |
