Abstract: The invention provides an apparatus for adjusting the flow of a fluid within a conduit, comprising a slide plate with a flat body and a fixed plate with a flat body. The slide plate and fixed plate have openings on their bodies. At a fully closed position, the openings of the slide plate do not substantially overlap with the openings of the fixed plate. By rotation of an actuator shaft and drive pin disposed thereon, the slide plate may move relative to the fixed plate, whereby the openings of the slide plate begin overlapping with the opening of the fixed plate, thereby allowing flow of fluid through the openings. Sequentially or independently from the movement of the slide plate, rotation of the actuator shaft may cause the fixed plate to rotate relative to the walls of the conduit, whereby flow of fluid may pass through the opening between the conduit and fixed plate assembly.

Abstract: An apparatus for sampling room air-conditions comprising a sensor well having a discharge opening into which sensor well is placed a sensor, a fan for passing room-air past the sensor, a discharge plenum outside of the sensor well for receiving room-air discharged from the sensor well discharge opening and diffusers for discharging received room-air in directions away from the room-air sensor well. A method for sampling room-air conditions wherein the room-air is passed by a sensor, dispensed in directions to envelop the room-air to be sensed and prevented from contacting or mixing with the room-air to be sensed by the sensor with air not passing the sensor.

Abstract: An air flow sensing device comprised of rotatable spaced dampers, shafts to rotate the dampers, a counter-weight attached to a shaft biasing the dampers to a closed position with respect to air flow and pressure sensor means to determine the velocity of the air passing between and around the dampers when the dampers are in a closed position.