Abstract: A multi-function fluid flow monitoring apparatus capable of measuring fluid flow-related variables of fluid in a channel on the basis of signals from any one or more of a plurality of different types of flow sensors. Such different types of flow sensors may include, for example, a bubbler-type pressure sensor, a submerged pressure transducer, an ultrasonic transducer, and/or a velocity sensor forming part of an area-velocity sensor system, each of which sensors may be selectively connected to the apparatus as needed to accommodate various monitoring conditions. The apparatus is further capable of monitoring various conditions of fluid in the channel, such as pH level, ORP, temperature, solution conductivity, dissolved oxygen, and the like.

Abstract: A fiber optic system and method in which the transmission of light through a fiber optic core of a fiber optic element is stabilized and optimized by eliminating the destabilizing effect of light independently propagated along the clad of the fiber optic element. The propagation of light along the clad may be essentially eliminated by a field stop member disposed between a light-receiving end of the fiber optic element and an LED light source, whereby light from the LED is entirely shielded from the clad. The field stop member is particularly effective when used in a fiber optic sensor, wherein the effect of clad light on transmission of light through the core is particularly destabilizing. Alternative structures for mitigating or eliminating the destabilizing effect of clad light are also provided in the form of alterations of the clad structure, or by providing a clad light stop diaphragm at the light-emitting end of the fiber optic element.