Patent ID: 7073403
Filing Date: 2006-07-11
Classification: G08B

Abstract:
1. A system for the monitoring of a gaseous atmosphere to detect a particular chemical compound in said atmosphere and to confirm the presence or absence of that compound, said system comprising: a monitor and alarm system that is arranged to cyclically and continuously monitor said gaseous atmosphere by drawing a sample from said gaseous atmosphere and to immediately thereafter analyze said sample to detect and to report the presence of said compound; a confirmation sampler, said confirmation sampler having at least two sorbent-containing sampling tubes and including a four-port, two-position valve and four check valves arranged in association with said sampling tubes to direct flow of the gas being sampled through a first one of said sampling tubes and then to exhaust and to direct a stream of hot purge gas through the second one of said sampling tubes and then to an analytical instrument when said two-position valve is in a first position, and to direct a stream of hot purge gas through the first of said sampling tubes and then to an analytical instrument, and to direct flow of the gas being sampled through the second one of said sampling tubes and then to exhaust when said two-position valve is in its second position; means for drawing a gaseous sample alternately through the first of said sampling tubes and then through the second of said sampling tubes; means for purging contaminants sorbed on packing contained in said sampling tubes after said gaseous sample has been drawn through the tubes; means to synchronize the cyclic operation of said monitor and said confirmation sampler so that during that time interval during which the monitor is sampling, so also is one of said tubes of the confirmation sampler; means responsive to a report of said chemical compound generated by the monitor, said responsive means arranged to cause said confirmation sampler to retain and not to purge that sampling tube employed during the cycle of said monitor that generated said report.