Features and Benefits:
- Optimize Fan Performance. The FAN-Evaluator provides the accurate fan inlet and outlet airflow information needed to optimize equipment and process performance.
- Lo-Tchebycheff Sensor Location. A high concentration of total and static pressure sensors positioned according to the log-Tchebycheff rule sense the multiple and varying flow components that constitute the airstream’s velocity profile. The log-Tchebycheff’s perimeter weighted sensor pattern is utilized to minimize the positive error (measurements greater than actual) caused by the failure to account for slower velocities at the duct wall when using traditional equal area sensor locations. Spacing of total pressure sensors is per ASHRAE 1993 Fundamentals Handbook. Since the static pressure across the station is relatively uniform, a lesser number of static pressure sensors are utilized to minimize unrecovered pressure drop.
- Fechheimer Pitot Flow Measurement. The FAN-Evaluator operates on the Fechheimer Pitot derivative of the multi-point, self-averaging Pitot principle to measure the total and static pressure components of airflow. Total pressure sensing ports with patented (U.S. Patent No. 4,559,835) chamfered entrances, and Fechheimer pairs of offset static pressure sensing ports combine to minimize the effect of directional airflow. When located downstream of honeycomb airflow processing cell, the Fechheimer Pitot method is extremely effective at accurately measuring airflow in limited straight duct runs.
- Airflow Processing. To assure extremely high levels of measuring accuracy (2% of actual flow or better) under extreme conditions caused by turbulent, rotating, and multi-directional airflows normally present near fan inlets or discharge ducts and directly downstream from duct elbows, transitions, etc., the FAN-E uses open, parallel cell, honeycomb panels to “process” the air into straightened flow just prior to the total pressure measurement plane. These honeycomb panels sharply reduce the need for long, straight runs of duct before and after the station to obtain accurate flow measurement.
- Patent No. 3,748,901.
- Negligible Airflow Resistance. The FAN-Evaluator airflow measuring station is designed to function while producing a minimum of resistance to airflow, due to the unique honeycomb air straightener-equalizer section having a free area of 96.6%.
- Configurations. Rectangular, Circular, and Custom.
- Accuracy. 2-3% of actual flow.
- Operating Temperatures. Continuous operation to 800ºF.
- Connection Fittings. 1/2″ FPT, Type 316 stainless steel.
- Static and Total Pressure Sensing Manifolds. Type 316 stainless steel, welded construction.
- Airflow Straightener. 1″ hexagonal, parallel cell straightener, 3″ deep, 24 ga. (0.24″) thick carbon steel.
- Casing and Flanges. 3/16″ carbon steel, continuous welded seams. Casing depth is 12″.
- Special Construction Options. Sensing Manifold Cleanouts, Inlet Bell Mouth, Multi-point Temperature Measurement, Alternate Materials of Construction, Integral Control Damper.
