Drive belt tensioning system for air-cooled heat exchangers

An air-cooled heat exchanger comprising:

• a frame assembly;
• a plenum supported by the frame assembly;
• an engine, wherein the engine includes a drive shaft;
• a fan assembly configured to move air through the plenum, wherein the fan assembly comprises a fan connected to a fan shaft;
• and
• a drive assembly connected between the engine and the fan assembly, wherein the drive assembly comprises:
• a fan shaft sheave connected to the fan shaft, wherein the fan shaft sheave has a width;
• a driver sheave connected to the drive shaft;
• an idler pulley;
• an idler shaft connected to the idler pulley;
• one or more idler shaft bearings that support the idler shaft;
• an idler bearing track;
• an idler bearing shuttle configured to receive the idler bearing track and configured for linear movement along a longitudinal axis of the idler bearing track, wherein the one or more idler shaft bearings, idler shaft and idler pulley are attached to the idler bearing shuttle;
• a drive belt in contact with the fan shaft sheave, the driver sheave and the idler pulley, wherein the drive belt follows a drive belt path that does not extend beyond the width of the fan shaft sheave;
• and
• an idler bearing adjustment mechanism configured to adjust the position of the idler pulley relative to the fan shaft.