Nozzle pitot averaging primary

A nozzle pitot primary device for measuring air or gas flow within a system of air or gas fluid moving within a conduit comprising:

• fluid constricting means in the form of a nozzle having an external wall that defines a fluid flow opening therein for allowing a fluid such as air or gas to pass therethrough and further including an inlet end and an exiting end and wherein the external wall of said nozzle is flared inwardly from said inlet end towards said exiting end such that fluid is constricted as it passes therethrough, said nozzle being adapted to be positioned with respect to said conduit such that fluid passing through said conduit is constrained to move through said nozzle;
• pitot means operatively associated with said nozzle and positioned in the path of the fluid passing therethrough for effectively sensing the differential velocity pressure of the fluid passing through said nozzle, said pitot means including an array of averaging static and total pressure pitots disposed in a loop type configuration about said nozzle with pitots of said array having sensing ends that generally lie in a transverse plane across said nozzle;
• said total pressure pitots including a plurality of openings spaced and disposed along the loop configuration with the openings being oriented to face the flow within said nozzle;
• said static pitots including a plurality of openings spaced and disposed along said loop configuration but which are oriented such that they face a direction generally perpendicular to the direction of flow within said nozzle;
• said loop configuration extending around the central axis of said nozzle and spaced inwardly of the adjacent external wall structure and wherein openings of both said static and total pressure pitots lie along the same loop configuration;
• said total pressure pitots including a central point located along the central axis of said nozzle, a plurality of communicatively connected manifold extensions extending radially from said central point to the sensing ends of the respective total pressure pitots, and a total pressure line communicatively connected to at least one of said total pressure manifold extensions and leading therefrom for channeling a total pressure signal to appropriate instrumentation;
• said static pressure pitots including a central point located along the central axis of said nozzle, a plurality of communicatively connected manifold extensions extending radially from said central point to respective sensing ends of said static pressure pitots;
• and a static pressure line communicatively connected to at least one of said static pressure manifold extensions and leading therefrom for channeling a static pressure signal to appropriate instrumentation;
• and wherein said nozzle is shaped to provide flow constricting means for directing the system of fluid therethrough in such a manner that the resulting velocity profile of the moving fluid is relatively uniform across a substantial portion of the cross-sectional area of the fluid flow opening within said nozzle, thereby enabling a relatively accurate determination of fluid flow to be made.