Forced or induced draught fans associated with air cooled heat exchangers are known universally as “fin fans.” They may be fitted in large banks to cool process fluids or be an integral part of a gas compression skid. Drive arrangements will vary and may include either belt drive or a gearbox, but all will normally be electric motor driven, sometimes by variable frequency drives. Fin fans, if monitored at all, have historically been covered by any of the following monitoring method:
- Transmitters: - to send a simple 4-20 mA signal to a DCS for Transmitters indication and trending
- Scanning Systems: - to provide dynamic vibration data updated Scanning System
The distributed nature of the product reduces installation costs which otherwise often exceed half of the project budget. Each fin fan is fitted with two accelerometers, one each on the motor and driveshaft. Two SKF Multilog DMx modules and their IS power supply are located centrally to the four heat exchanger fans. Twin RS-485 communications links may be used. The first data path is to the DCS for status indication and motor control.
By monitoring these Fin Fans an enhanced information in achieved as the Scalar values and alarms based on the vibration of discrete components – shaft, belts, gears, bearings are available on the dashboards – not just a “high vibration” alert.
Additional wireless Temperature sensors can also be installed in the shaft present after the FinFans’s in order to change the speed of the FinFan based on the effective cooling being done by them in order to enhance the process efficiency further more.