Ace Glass 8766-12 Firestone Rapid Purge Valve with Hose Connection

A rapid, efficient and foolproof purge valve for 100% replacement of air in reaction vessels with any desired gas (N₂, H₂, Ar, CI₂, etc.). No mercury used, no reducing valve needed on gas source, no high vacuum source necessary. No need to watch manometers, hand control gas flow, or install warning systems to prevent accidents. Expensive gases are conserved because once purging is complete, the flow can be cut almost to zero. This valve is so inexpensive, it is possible to run all reactions under nitrogen as easily as not. For manifold using 8766 valve, see 8765.

How It Works:

Connect reaction vessel, house vacuum, and purge gas to valve via 10 mm O.D. connections. On vacuum cycle, Fig. A, air is removed from the reaction vessel while the stop valve is closing. When filling is complete, Fig. B, the stop valve reopens to prevent pressure buildup. Thus, a simple half turn of the stopcock alternates the reaction system from vacuum to gas flow as fast as desired. In small systems, a complete cycle takes as little as one to two seconds. With only 1/2 atmosphere house vacuum, ten cycles removes all but .510 atmospheres of air. About 70 cycles gets you down to the last molecule of oxygen. After purging, the system is kept under slight positive pressure indefinitely, with a slow bubbling of the gas to prevent diffusion of air past the joints. If the reaction evolves a gas, no pressure builds up, and it may even be collected and measured while maintaining a controlled atmosphere. Proper selection of the liquid for the seal allows purging with any gas that does not react with glass. Liquid not supplied.