FAD (Free Air Delivery) Meter

FAD (Free Air Delivery) Meter
Compressors are the most crucial part and the largest energy consuming component of any compressed air network. Without reliable measurement of the output of compressors, any initiative to optimise the compressed air system is likely to result in only minimal impact.

Various studies show that the biggest loss of energy takes place at the point of generation. Nearly 60% of the energy consumed by a compressor is lost in the form of heat and friction losses. Improper maintenance, under-loaded operations and environmental factors add to further loss of generation efficiency. In such a scenario it becomes even more vital to monitor the output of compressors on a online basis.

Forbes Marshall’s FAD (Free Air Delivery) Meter is the most accurate and most efficient way of monitoring and measuring a compressor’s output and efficiency.
Based on the Vortex Flow Measurement principle, the FAD Meter has the unique feature of being the only flow metering solution with inbuilt online Pressure and Temperature compensation.
FAD Meter v/s Orifice Flowmeters FAD Meter v/s Thermal Massmeters Features & Technical Specifications Downloads
S. No.
Forbes Marshall FAD Meter
Orifice Flowmeters
1. Working Principle - based on the development of a Karman vortex-shedding street in the wake of a body built into the pipeline.

The periodic shedding of eddies occurs first from one side and then from the other side of a bluff body (vortex-shedding body) installed perpendicular to the pipe axis. Vortex shedding generates a so-called "Karman vortex street" with alternating pressure conditions whose frequency is proportional to the flow velocity.
With an orifice plate, the fluid flow is measured through the difference in pressure from the upstream side to the downstream side of a partially obstructed pipe. The plate obstructing the flow offers a precisely measured obstruction that narrows the pipe and forces the flowing fluid to constrict
2. Accuracy: ±1% of measured value Accuracy: ±3% of measured value
3. Pressure & Temperature Compensation: Inbuilt and Online compensation Pressure & Temperature Compensation: Pressure compensation not available. Additional pressure & temperature transmitters and flow computer required, further reducing accuracy
4. Pressure Drop: Very negligible. Usually < 0.05 bar. Hence reduced energy consumption Pressure & Temperature Compensation: Very significant. Usually > 0.2 bar. Hence greater energy consumption
5. Reliability: Resistant to damage, wear and tear. No erosion of precision of readings Reliability: Any wear and tear causes drop in accuracy of readings.
6. Sensor located behind bluff body – safe from dirt and particulate matter carried in air Susceptible to damage from dirt and particulate matter from wear and tear