Valves Bodenstein

A slightly modified, very rugged version of the Bodenstein valve has been developed by Kistiakowsky and described by Vaughn... 

For preparatory work, the rather expensive Bodenstein valves may frequently be replaced by a combination of fusing of connections (closure) and break-seal valves (opening), if it is sufficient to open or close a connection only once. 

We can discuss here only a few of the numerous recommendations on how to introduce small quantities of gas into a vacuum, while retaining precise control over the flow. In many cases it is sufficient to file fine grooves in the plug of a glass stopcock, starting at the bore. In these cases, stopcocks with inclined bores (offset arms) should be used as much as possible. The Bodenstein valve is also usable for fine control, although the adjustment is not exactly reproducible. A metal needle valve is the best means of control. 

Fig. 182. Preparation of thionyl imide. ft) Bodenstein valve G) needle valve condensation trap m ) manometer r) reaction vessel Sj, Sg) flowmeters ...

The stopcocks must be greased with fluorocarbon lubricant because of the corrosive effect of Cl30g, unless one prefers to use the glass valves su ested by Bodenstein. 

---