High temperature gas sampling apparatus and method

A process for sampling a high temperature gas mixture with an elongated probe having a first passageway extending from a sampling orifice at one end of the probe through the probe and a second passageway communicating with a rearwardly inclined circumferential slot in communication with said sampling orifice in the first passageway in the probe wherein a cooled sample of the high temperature gas mixture withdrawn through the probe has a chemical composition very close to the chemical composition of the high temperature gas mixture and any condensible constituents form spheroids, said process comprising inserting the end of the probe with the sampling orifice into the gas mixture to be sampled, drawing a gas sample into the probe through the sampling orifice, expanding relatively cool diluent fluid under relatively high pressure at or above sonic velocity through the rearwardly inclined circumferential slot, and directing the expanded diluent fluid into the passageway as a conical shaped curtain of diluent fluid with the apex of the cone directed in the direction of the flow of the gas sample as the gas sample is drawn through the orifice into the probe to expand the diluent fluid and mix it with the high temperature gas mixture being extracted through the probe to rapidly cool the gas mixture thereby minimizing changes in the chemical composition of the high temperature gas mixture sample and forming spheroids of any condensable constituents.

A process for sampling a heated gas with an elongated probe having a first passageway extending along the center of the probe from a sampling orifice at one end of the probe, a second passageway concentric with the first passageway and communicating with an annular orifice in the first passageway, a third passageway concentric with the first passageway and extending over an exposed length of the probe and a fourth passageway concentric with the third passageway and communicating with the third passageway at the end of the probe adjacent the sampling orifice, wherein a cooled sample of the high temperature gas mixture retains a chemical composition very close to the chemical composition of the high temperature gas mixture, said process comprising inserting the end of the probe with the sampling orifice into the high temperature gas mixture to be sampled, extracting a gas sample through the sampling orifice, injecting relatively cool diluent fluid under relatively high pressure at or above sonic velocity through the annular orifice at an angle directed away from the sampling orifice and into the first passageway as the gas sample is drawn through the probe to expand within the first passageway, mix with the gas sample and very rapidly cool the gas sample to prevent any change in the chemical composition of the gas as it is cooled and flowing a cooling fluid through the third and fourth passageways to prevent the probe from melting or being damaged by the high temperature gas mixture.