Patent ID: 7651866

Claim:
A purge and trap concentrator, comprising: a sample processing system operating according to a system cycle of a sequence of processing steps including at least a purge step, a desorption step and a bake step, the sample processing system comprising: a sparger having a sample inlet adapted to receive a chemical sample; a trap in fluid communication with the sparger through a two-position valve; a valve manifold comprising a vent valve in fluid communication with a vent the sparger and the trap, and a purge valve in fluid communication with a purge gas inlet adapted to receive a purge gas and the sparger; a sample outlet in fluid communication with the two-position valve; and a heated valve in fluid communication with the sparger, the purge valve, and the trap; wherein the valve manifold and the two-position valve control the distribution of gas flow through the sample processing system in different flow paths as a function of electrical inputs; an electronic flow controller in fluid communication with the purge gas inlet at an inlet to the flow controller, and in fluid communication with a purge gas inlet of the valve manifold at an outlet from the flow controller, wherein the flow controller is configured to control the flow of purge gas delivered to the sample processing system, and wherein the flow controller provides an electrically adjustable rate of flow of the purge gas to the valve manifold in the sample processing system as a function of an electrical input wherein the electronic flow controller allows the rate of flow of the purge gas to be changed for specific modes of operation of the sample processing system; and a digital controller providing the system cycle and providing the electrical inputs to at least the flow controller, the valve manifold and the two-position valve, the electrical inputs varying as a function of the system cycle to automatically change the flow path of the purge gas between system cycle steps and to automatically increase the rate of flow of purge gas during the bake step relative to the rate of flow of purge gas during the purge step.