Patent ID: 7198753

Claim:
A monitoring system, comprising: a first chemical vessel containing a first chemical mixture; a second chemical vessel containing a second chemical mixture; a sensor configured to selectively receive a first sample flow of said first chemical mixture from said first chemical vessel and to selectively receive a second sample flow of said second chemical mixture from said second chemical vessel, wherein said sensor is configured to measure a first sample attribute of said first sample flow and a second sample attribute of said second sample flow; a supply distribution system configured to selectively transport said first sample flow and said second sample flow to said sensor; a purge fluid supply, wherein said supply distribution system is further configured to selectively transport a purge fluid flow from said purge fluid supply to said sensor; a drain configured to receive fluids; and a return distribution system wherein said return distribution system is configured to transport purge fluids from said sensor to said drain, and wherein said return distribution system is configured to selectively transport said first sample flow from said sensor to said first chemical vessel or to said drain, and wherein said return distribution system is configured to selectively transport said second sample flow from said sensor to said second chemical vessel or to said drain.