| 摘要 |
1456268 Silica tube manufacture QUARTZ & SILICE 12 Feb 1974 [8 March 1973] 06279/74 Heading C1M A silica tube is heated and externally coated with fused silica grains and is stretched and subjected to internal pressure whereby a tube of desired dimensions is produced. The coating, stretching and pressurization may be effected simultaneously and may be repeated at a series of stations down a production line. The heating may be by means of a plasma torch or gas burners, the pressure may be obtained by inflating the tube internally or applying a vacuum externally. Prior to treatment a preformed tube may be joined to the tube already undergoing treatment. In Fig. 3 pressure is developed in the heated tube 2 by gas blown in through plug 20a and clack valve 22a and retained by plug 20 and valve 22, the plugs being held in place by the magnetic fields from coils 21a and 21. In Fig. 8 the preform is joined to the tube at station 50, the tube is coated and inflated by external vacuum at station 52 and again at station 54 with no deposition with stretching at stations 53 and 55. Means for transporting the tube and rotating it during treatment are disclosed.
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