Philadelphia Gear

Air Preheater Drives

The air preheater system is designed to use the heat contained in boiler exhaust gases that would otherwise be lost out of the power plant boiler smokestacks. In the preheater, this waste heat is captured before it enters the stack and is used to heat the incoming cold air, elevating its temperature by as much as 400° F.

Whether the gear drive is used in a horizontal or vertical air preheater system, its function is still the same. However, the characteristics of these gear drives can be quite different.

Primary features of horizontal (HR) air preheater drives:

  • Horizontally offset, triple reduction, parallel shaft gearing configuration
  • Double helical gearing supported by rolling element bearings
  • Splash lubrication of rotating elements
  • Special features include a double extended high-speed shaft to accommodate an auxiliary or back-up drive used for emergency operation when the primary drive ceases to function

Air preheater drives are equipped with backstops to ensure no reverse rotation. Temperature sensors for measuring lube oil temperatures are designed for the application.

Primary features of vertical air preheater (AP) drives:

  • Vertically offset, bevel helical, triple reduction gear configuration
  • Bevel gearing (1st reduction) and single helical gearing (2nd and 3rd reductions) supported by rolling element bearings
  • Pressure lubrication of rotating elements by a shaft-driven oil pump
  • Special features include multiple bevel input shafts to accommodate optional auxiliary or backup drives

Air preheater drives are equipped with backstops to ensure no reverse rotation. Temperature sensors for measuring lube oil temperatures are designed for the application.

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