Probe for measuring steam quality

Abstract

A probe for insertion into a steam flow which provides a quality measurement of the steam in that particular flow. Steam quality is determined by transmitting light across a portion of the steam flow, making a measurement of the light's intensity after traversing the steam flow, and comparing that intensity to light intensity which was measured through a dry steam flow. Light provided by a Helium-Neon laser is directed through a diverging lens which distributes the emitted light across a predetermined area. Such distributed light is directed through a light beam splitter which directs a portion of the light beam through a series of optic fibers. Such optic fibers transmit light through an isolation window, and across a steam flow specimen channel where it is reflected by a mirror. The reflected light from the mirror traverses the optic fibers in the opposite direction to light emitted from the laser. At least a portion of such oppositely directed light impinges on a photodetector which indicates the light's intensity passing through the steam channel and such integrity is compared to the light intensity which penetrates the steam channel flow specimen for completely dry steam. Fiber optics are used for transmitting the light over extended distances and in skewed, crooked directions. Conduits are provided for transporting non-condensible purging substances to the mirror's reflective surface and to the surfaces of the window barrier so as to prevent steam condensation thereon and avoid fallacious steam quality readings resulting therefrom.