Sample and carrier gas pre-heat system for gas chromatograph

摘要

A novel gas chromatograph includes suitably located backpressure restrictors. In a preferred embodiment, each backpressure restrictor consists of capillary tubing with a pressure drop across it controlled to be less than or slightly greater than 0.528. One embodiment places the backpressure restrictor upstream of an initial stream switching valve and downstream of sample pre-heat coil. Another embodiment places the backpressure restrictor downstream of the gas chromatograph's measurement element and its carrier pre-heat coil. In each case, only a controlled and predictable flow rate is achieved, both regulating the flow rate through the system and back pressuring fluid to remain in the respective pre-heat coils to achieve ideal temperature.