Abstract: In a gas chromatography apparatus, a carrier gas is flowed from a carrier gas supply toward an analytical column at a carrier gas pressure. A sample is added to the carrier gas to form a sample gas. The sample gas is flowed through the analytical column to a gas detector that includes a sample gas outlet communicating with a gas buffer vessel. The carrier gas pressure is controlled relative to a buffer pressure of the gas buffer vessel.

Abstract: In a gas chromatography apparatus, a carrier gas is flowed from a carrier gas supply toward an analytical column at a carrier gas pressure. A sample is added to the carrier gas to form a sample gas. The sample gas is flowed through the analytical column to a gas detector that includes a sample gas outlet communicating with a gas buffer vessel. The carrier gas pressure is controlled relative to a buffer pressure of the gas buffer vessel.

Abstract: The pressure of a carrier gas entering a gas chromatography (GC) column is controlled by increasing or decreasing the gas pressure over a pressure change cycle by which a desired gas pressure is obtained while avoiding pressure pulses in the column. The pressure change cycle may follow a function that dictates the rate of pressure change. A gas flow controller that controls the gas pressure at the inlet or head of the column may be operated to implement the pressure change cycle. The gas flow controller may be controlled by an electronic controller.

Abstract: An example of a gas detection system includes a gas chromatograph oven, a gas detector, a sample gas moving device, and a flow detector. An example of a method for detecting gas includes flowing a sample gas from the oven, determining whether the flow rate equals or is less than a minimum, and determining whether the concentration of a first gas of the sample gas, such as a combustible gas, equals or exceeds a maximum. If either the flow rate or the concentration indicates an error condition or is out of bounds, an alarm response is initiated. The alarm response may include shutting off the flow of the first gas to the oven, and flowing a second gas, such as a safe gas, to the oven.