SD flowpath selectors select one of 4 to 16 dead-ended streams. This example illustrates a method for sampling non-pressurized containers which eliminates any possible effect from pressure differences among the containers, providing accurate and repeatable results.
In step 1, a vacuum pump moves sample from the container selected by the SD valve to a 6 port sampling valve. In step 2, the 3 port valve blocks the vacuum flow through the sampling valve to allow the sample within the loop to equilibrate at atmospheric pressure. Then in step 3, the 6 port valve is switched, injecting the sample.
All three valves can be automated with air or electric actuators for unattended operation.
Click below to change the valve position. (Currently shown in Step 1 position)
1: Sample pulled from selected container into the sample loop of the injector
2: Vacuum blocked, loop contents equilibrate
3: Contents of the sample loop injected onto the column
