Abstract: A flow valve with an integral pressure-independent fluid flow controller for controlling the flow of fluid and corresponding methods for controlling fluid flow are provided. The flow valve comprises a valve body, one or more valve blades arranged on the valve body for controlling fluid flow in a duct section, an actuator for modulating the one or more valve blades, a flow sensor or sensors for sensing fluid flow, a tuning calculation module adapted for determining or monitoring a pressure drop across the valve body and for calculating tuning constants based on the pressure drop, and a controller for controlling the actuator based on a difference between a fluid flow setpoint and the sensed fluid flow in accordance with the tuning constants. The pressure drop may be determined from an algorithm based on blade position and sensed fluid flow, or may be directly measured.

Abstract: A probe for use in monitoring intake air volume in an air handling system operates in a turbulent stream found at locations near an intake for outside air. The probe has a very large transverse peripheral profile and includes a front face having a very large impact area so as to substantially disturb the turbulent stream and effect a substantial change the direction of flow of the turbulent stream, enabling accurate measurement of differential pressures to determine intake air volume with greater precision.