Methods of and system for clean air delivery to lightguide fiber drawing apparatus

A delivery system for providing air having a predetermined cleanliness to a drawing apparatus in which lightguide fiber is drawn from a preform which is suspended with a longitudinal axis thereof being oriented vertically, said system including:

• enclosure means for partially surrounding at least a portion of the preform, a portion of a length of the drawn fiber and portions of the drawing apparatus to substantially isolate the portions of the preform, the fiber and the drawing apparatus from ambient air, said enclosure means including a plurality of unit sections which are stacked to provide an enclosure means having a predetermined height with each unit section having an opening at each of its ends to permit passage of the fiber therethrough and an opening in a sidewall thereof;
• means defining a flow passage being associated with each said unit section and having a first end, which communicates with air that is ambient to the drawing apparatus for providing an intake for ambient air, and having a second end for providing an exit that communicates with the associated unit section, said opening in the sidewall of each said unit section being opposite to said exit of the associated flow passage;
• moving means for causing ambient air to be drawn into each said intake, flowed through each of said flow passages, and directed into said enclosure means transversely past the preform and the fiber and through said openings in said sidewalls of said unit sections;
• and
• filter means mounted in each said flow passage for removing contaminants to cause the air that is directed past the preform and the fiber to have a predetermined cleanliness.

A method of providing air having a predetermined cleanliness to drawing apparatus in which lightguide fiber is drawn from a preform, said method including the steps of:

• providing a flow passage having a first end which communicates with air that is ambient to the drawing apparatus and having a second end which is adjacent to the preform and the fiber, said flow passage being arranged to direct air transversely of the fiber and the preform;
• surrounding a portion of the preform and of the fiber with an enclosure which communicates with the second end of the flow passage and which has an opening that is opposite to the second end of the flow passage;
• and
• causing ambient air to be drawn into the first end of the flow passage, moved through the flow passage into the enclosure and directed in a substantially laminar flow transversely past the portions of the fiber and preform which are surrounded by the enclosure, and then through the opening;
• while
• filtering the air which is moved through the flow passage to remove contaminants and to cause the air that is directed past the fiber and the preform to have a predetermined cleanliness.

A method of providing air having a predetermined cleanliness to drawing apparatus in which lightguide fiber is drawn from a preform which is suspended with a longitudinal axis thereof being oriented vertically, said method including the steps of:

• surrounding a portion of the preform and of the fiber with an enclosure, the enclosure including a unit section having a predetermined height and openings at ends to permit passage of the drawn fiber, and an opening in a sidewall thereof, and said step of surrounding includes stacking a plurality of the unit sections along the longitudinal axis of the preform and a path along which the fiber is drawn,
• providing a flow passage for each of the unit sections, each flow passage having a first end which communicates with air that is ambient to the drawing apparatus and having a second end, which communicates with an associated unit section and which is generally opposite to the opening in the sidewall of the associated unit section, said flow passage being arranged to direct air transversely of the fiber and the preform;
• causing ambient air to be drawn into the first end of each flow passage, moved through the flow passages, and directed into the unit sections of the enclosure transversely past the portions of the fiber and preform which are surrounded by the enclosure, and then through the openings in the sidewalls of the unit sections;
• while
• filtering the air which is moved through the flow passages to remove contaminants and to cause the air that is directed past the fiber and the preform to have a predetermined cleanliness.