Glass drawing machines

Glass capillary columns were invented shortly after GC but did not see wide routine use, as the original glass columns were difficult and expensive to make, requiring an elaborate glass drawing machine, beyond... 

A Shimadzu GDM-1 glass-drawing machine was modified in our laboratory in approximate accord with the work of Schenning, van d Ven, and Venema (11). 

Soda-lime and borosilicate glass capillary columns can be made in the laboratory using a glass drawing machine. The glass tube is fed into an electrically heated softening furnace at a controlled speed and drawn out at the lower end by a pair of motor-driven rollers. Capillary columns of different dimensions are drawn by maintaining a fixed differential between the feed rate of the stock tube to the furnace and the... 

It took some time for the pioneers in the use of glass WCOT columns to convince others that these were sufficiently robust for routine employment in the laboratory. There was never any doubt as to the resolution attainable or about the inertness of the surface, the latter being of particular importance to lipid analysts concerned with any potential isomerization of polyunsaturated fatty acids. Interest was heightened when glass drawing machines for capillary production became available commercially at reasonable cost. 

FIG. 97. Plan of a sheet glass tank for the FourcauU system using 9 drawing machines. 

The simplest setup of a drawing machine is a drawing pin (with one yarn wrap around it) and a hotplate (the yarn loosely touches the surface) between two rolls (see Figure 17.12a). The pin is heated to about the glass transition temperature, while the hotplate is held at a temperature safely below the melting temperature. The speed ratio of the two rolls is the adjusted draw ratio (for example, 5.4x). The yarn necks on the pin and completes a natural draw (for example 3x). The remaining factor (1.8x) is the draw ratio over the hotplate. One lets the as-spun yarn decide how and where it wants to draw, which is not necessarily the optimum situation. 

Fig. 7.4. Drawing equipment for the contact-free production of clear silica glass tubes, where 1 is the silica glass ingot (preform), 2 the drawn tube, 3 the furnace (graphite resistance-heated), 4 the drawing machine, 5 the supporting assembly and 6 the onion...

Figure 25 Fully automatic inspection machine with vision system for inspection of vials filled with lyophilized product. 1, Inspection of cap, crimp, and shoulder and neck area 2, feed-in 3, inspection for heel cracks 4, inspection for particulates on the bottom of the cake or glass cracks on the bottom 5, inspection for particulates on the cake surface 6, inspection of side wall for glass cracks, product splashes, and melt-backs 7, inspection of side wall for glass cracks, product splashes, fill levels, melt-backs 8, exit of good product 9, exit of rejected vials class A 10, exit of rejected vials class B 11, inspection of neck and shoulder area. (Drawing and equipment, Seidenader Maschinenbau GmbH, D-85551 Kirchheim/Miinchen, and Seidenader Equipment Inc., Florham Park, NJ 07932.)...

FIG. 1.2. Tube drawing by machine. Tlie Danner Process. The molten glass from the continuous furnace flows on to the hollow rotating mandrel and is drawn off as a Uibe. 

FIG. 1.3. (Right) Tube drawing by machine. Tlie Velio Pi ocess. The molten glass flows into the rotating "sink", here shown in section, and emerges as a tube. Tlie tube is drawn away by rollers or tracks similar to those in Fig. 1.2. 

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