Method and apparatus for concentrating a VOC sample
AssigneeTeledyne Tekmar Company
InventorDavid M. Neal
Life of this patent
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Abstract
A system for concentrating a volatile organic compound (VOC) sample uses in one embodiment a bypass line and a valve coupled thereto to regulate an amount of carrier gas flowing through a carrier gas line. A flow splitter fluidly couples the bypass line to the carrier gas line, and connects to the output of a cryofocuser. The valve opens at the onset of transferring the VOC sample from a concentrator trap such as a sorbent trap to the cryofocuser, thereby resulting in an increased amount of carrier gas flow between the concentrator trap and the cryofocuser for more efficient desorbing of the concentrator trap. The valve is closed when the focused VOC sample is flushed out of the cryofocuser for delivery to a gas chromatograph, preferably delivering the entire VOC sample to the GC.
Claims11
A sample concentrator, comprising:
- a focusing trap having an inlet and outlet, and being operable between a focusing absorb mode and a focusing desorb mode;
- a focusing trap feed line connected in series to the inlet of the focusing trap;
- an instrument feed line connected in series to the outlet of the focusing trap;
- a bypass line fluidly coupled to the instrument feed line;
- a bypass valve fluidly interposed between the bypass line and a vent, for regulating flow rate through the bypass line;
- a concentrator trap having a concentrator absorb mode and a concentrator desorb mode, the concentrator trap being selectively in fluid communication with the focusing trap through the focusing trap feed line;
- at least one trap controller operably coupled to the focusing trap and the concentrator trap for operating the focusing and concentrator traps between their respective absorb and desorb modes;
- and
- a valve controller operably coupled to the bypass valve for operating the bypass valve to impede flow through the bypass valve during the focusing desorb mode, the valve controller being further configured to encourage flow through the bypass valve when the concentrator trap is in the concentrator desorb mode and is in fluid communication with the focusing trap.
Dependencies are inferred from the claim text.