in some way we must replace the T.E.G on the tray after a certain period. however it is not effcient to do this by stoppimg the process. instead we replace T.E.G CONTINUOSLY.new dry T.E.G is pumped to the tray while the water-entriched T.E.G. flow out the tray meanwhile the gas flows through the tray and partically dried. why do we say "partically"? Because one tray is not enough to dry the gas completely. the solution to this problem is to imstall several trays. if we look at the illustration we see that there are seven trays. the gas flowing upward will progressively lose its water. this system is very efficient but it has some disadvantage.