Thermometric apparatus and method for determining the concentration of a vapor in a gas stream

摘要

A sensor for sensing the concentration of a vapor of a volatile liquid in a gas is disclosed. The sensor has a dry-transducer temperature sensor and a wet-transducer temperature sensor. The wet transducer-temperature sensor is covered by a non-woven, non-flaking, liquid-permeable material to allow the liquid to pass from a source to about the wet-transducer temperature sensor and vaporize when the gas is not saturated with the vapor. The vaporization of the volatile liquid causes the temperature at the wet-transducer temperature sensor to have a steady-state temperature lower than the reference temperature measured by the dry-transducer temperature sensor. The difference in the temperature measured by the two temperature sensors being determinable to determine the concentration of the vapor in the gas. In an embodiment, the non-woven, non-flaking, liquid-permeable material is a porous membrane. In another embodiment, it is a gel.