Air Cooled Heat Exchangers

Air Cooled Heat Exchangers operational performance, and reliability are crucial to minimizing capital cost and operating expenditure.

Star’s Mechanical Repair Services:

  • Adjust fan pitch
  • Limit tip clearance
  • Fan replacement
  • Install new high efficiency fans
  • Motor replacement
  • Gear reducer replacement
  • Bearing replacement
  • Sheave/Sprocket/Pulley replacement
  • Belt replacement
  • Align belts and drives

Routine maintenance

The reliability and thermal performance of any ACHE depends on how well its mechanical components are maintained. The components of ACHEs are fairly common; typically each bay has one, two, or three electric-motor-driven fans. Most have a speed reducer consisting of either a belt drive (e.g., V-belt or cog belt) or right-angle gear drive. A belt-drive system has four bearings that need to be lubricated — two motor bearings and two fan bearings for each fan. These are typically tubed to a common location somewhere on the drive assembly so they can be lubricated while the exchanger is running. Manufacturers usually recommend that you grease the bearings once a month if the coolers are in continuous operation. Right-angle gear drives should be lubricated according to the manufacturer’s recommendations. Check belt tension on a regular basis, usually every six weeks at a minimum for ACHEs that are in continuous service. Check belts for wear, and sprockets for tooth wear or cracking. Inspect fans at least annually by following these procedures (4):

  1. Visually inspect each blade and the hub, looking for cracking, rubbing, or excessive wear.
  2. Check all bolting hardware for proper torque, especially the blade-clamping bolts.
  3. Check blades for proper pitch as per the ACHE specification sheet. 
  4. Check the blade tracking to be sure that all blades are riding in the same plane in the fan ring.
  5. Check blade tip clearances to be sure that they are all within recommended limits.