Powered capture hood

摘要

A powered capture hood assembly to measure volumetric airflow in heating and cooling systems and for ventilation fans. The capture hood assembly has a hood for capturing or providing airflow, a formed nozzle structure attached thereto for conditioning the airflow and a blower apparatus with an adjustable fan attached to the opposite end of the nozzle structure. Subsequent the positioning of the hood over a supply duct, for example, a fan speed controller is utilized to adjust the fan in the tubular blower member to provide a zero or null pressure reading between the venturi portion of the nozzle structure and the local ambient room pressure. A pressure gauge is utilized to measure the pressure differential between a pressure reference tap of the formed nozzle structure and the pressure tap of the blower apparatus to determine volumetric airflow.

主权项

1. A powered capture hood assembly to measure volumetric airflow comprising:
a) a hood structure for providing or capturing airflow; b) a formed nozzle structure having opposing first and second ends, said first end having means for connecting to said hood structure, said nozzle structure having a generally centrally disposed restricted area forming a venturi in said formed nozzle structure, said formed nozzle structure having a supply sensor and tap and a return sensor and tap; c) an airflow conditioning assembly disposed in said second end of said nozzle structure; d) a blower apparatus having an adjustable fan therein, said blower apparatus constructed for mounting to said second end of said nozzle structure, said blower apparatus having a pressure sensor and tap for sensing air flow; e) means to adjust the fan speed of said blower apparatus; and f) means to measure the pressure in said blower apparatus, said venturi portion of said nozzle structure and at said second end of said formed nozzle structure.