| 摘要 |
A method and apparatus for controlling an outside diameter of a preform bait tube (8) during a glass layer deposition process. The apparatus includes a gas source (20) in communication with an interior of the preform bait tube. A temperature monitor (35) measures a temperature of a hot zone of the preform bait tube and generates a temperature output signal indicative of the measured temperature. A diameter monitor (34) measures the diameter of the hot zone of the preform bait tube and generates a diameter output signal indicative of the measured diameter. A pressure measuring unit (33) measures the pressure in the interior of the preform bait tube and generates a pressure output signal indicative of the measured pressure. A control means (36) receives the temperature output signal, the diameter output signal, and the pressure output signal, and determines a total flow rate by adding together (1) a baseline flow rate associated the measured temperature, and (2) a flow rate adjustment based on the measured diameter and the measured pressure. The control means controls the gas source to output a gas at a flow rate equal to the total flow rate. <IMAGE> |
