Airflow Measuring Stations
NJK Precision has developed an airflow measuring station technology that includes 21 patented claims. The result is an airflow measuring station that is not subject to the same inaccuracy, placement restrictions, low flow limitations, pressure drop issues, and size restrictions that are inherent in other airflow measurement methods.
This airflow measuring station provides a unique, robust, and patented method of measuring airflow, even in the most challenging HVAC applications.
NJK Precision's air flow measurement station utilizes its patented dual chambered airfoil design to dynamically normalize turbulent airflows inherent within the ductwork.
The sampled air flow is measured through a single Mass Air Flow "Thin Film" sensing probe using advanced Thermal Dispersion Technology. Thin Film resistors have been in use for many years in high accuracy applications in laboratories and the automotive industry.
The NJK Precision Air Monitor Station samples the air flow from the outer edge of the ductwork. The sampled air is drawn through the single NJK Precision sensor tube where its internal diameter and length allow for 7.5 diameters of straight air flow to assist in evening out any remaining turbulence in the air being measured.
Superior Installation Options
The taming of the turbulent airflow results in more accurate measurements, which means the NJK Precision Airflow Measuring Station can be placed in more physically restrictive situations. While some products already accurately measure airflow at less than the ASHRAE Standard 111 recommendation for equivalent duct diameters away from an elbow, branch, transition, or fan, the NJK Precision Airflow Measuring Station sets a new, smaller equivalent duct diameter standard for station placement.
For example, instead of requiring that an air measuring station be located three equivalent duct diameters downstream from a 90° elbow, the NJK Precision Airflow Measuring Station can be placed just one equivalent duct diameter downstream of the elbow.
The NJK Precision Airflow Measuring Stations are built to order. Measuring stations are shipped unassembled to reduce shipping costs and to prevent damage. Field assembly is fast and simple. The Flow Measuring Module is already factory mounted onto a Flow Frame section. The sections are connected together with slip fit, field adjustable corner pieces that are tightened by a screw. Because field-provided dimensions are not always exact, each frame is built 0.5” smaller than the requested duct dimension.
More Precise Measurements
Each NJK Precision Flow Sensor Probe is calibrated and scaled for accuracy ratings from the maximum flow all the way through the minimum flow on a primary NIST Certified Air Flow Testing Stand that has a 0.19% uncertainty@ 95% confidence.
The station can measure airflow amounts with velocities as low as 50 feet per minute (FPM). This provides greater precision and can be used for applications like ventilation, building pressurization control, and critical applications by a building automation system.
NIST-traceable calibration over multiple flow points (25 to 37) from full flow down to the lowest measurable flow.