Abstract: The present invention relates to a device for fixing a tubular element in a cavity, which device is made up of hoops made of an elastically flexible material disposed in cross-sectional planes of said cavity, and means for retaining said element, said device being characterized in that, along the longitudinal axis of said cavity, said hoops are secured together by a flexible longitudinal support and are interconnected by a flexible membrane.

Abstract: The present invention relates to a device for fixing a tubular element in a cavity, which device is made up of hoops made of an elastically flexible material disposed in cross-sectional planes of said cavity, and means for retaining said element, said device being characterized in that, along the longitudinal axis of said cavity, said hoops are secured together by a flexible longitudinal support and are interconnected by a flexible membrane.

Abstract: The present invention provides a method of installing a tubular element in a cavity. The method comprises the following steps: preparing a unit comprising said tubular element and a layer of a fixing compound which covers the entire outer periphery of said tubular element, at least over a fraction of its length; positioning said unit along the inside wall of said cavity; and applying activation treatment to said compound in such a manner as to fix said tubular element to said inside wall. The unit is preferably placed on the bottom of the cavity.

Abstract: A method of installing a tubular member in an inaccessible cavity includes a step of cleaning the internal wall of the cavity, a step of bringing the tubular member into contact with retaining members, and a step of fixing the tubular member by pressing it against the wall of the cavity. The method comprises three successive phases. A first phase comprises the step of cleaning the internal wall of the cavity and a step of topographically surveying the internal wall of the cavity. A second phase comprises a step of determining a position on the internal wall for retaining members for retaining the tubular member and a step of installing on the internal wall retaining members for retaining the tubular member and fixing members for fixing the retaining members to the wall.

Abstract: In the fiber-drawing method, a first preform is lowered along a fiber-drawing axis through a fiber-drawing oven so as to be heated and drawn down into an optical fiber, and a second preform is lowered along the fiber-drawing axis through the fiber-drawing oven so as to be heated and drawn down in turn after the first preform has been withdrawn. While the first preform is being drawn down into a fiber, the second preform is heated in a preheating oven disposed adjacent to the fiber-drawing oven so as to raise the second preform to a temperature which is slightly below the fiber-drawing temperature, and the preheated second preform is transferred quickly onto the fiber-drawing axis after the first preform has been withdrawn therefrom. This method contributes to increasing the capacity for producing optical fibers.

Abstract: The invention relates to a method of assembling two optical fiber preforms together end-to-end, the method comprising the following operations: the two cylindrical preforms are placed in alignment along a common longitudinal axis; the preforms are rotated about the common longitudinal axis; the facing ends of said preforms are heated by a heater; and the preforms are moved towards each other parallel to the common axis to press them against each other so as to form intimate contact between the ends after cooling. According to the invention, the heating is performed by causing the preforms or heater to move in a radial direction orthogonal to the common longitudinal axis in such a manner as to heat the peripheries and then the cores of said preforms.