Type K Drives on Fly Ash Hopper Rotary Gates Save Vast Sums of Money and Time

Type K Series AH damper drives
Type K drive on rotary gate.
A power generating facility in the mid-West just took for granted that purchasing and replacing 40-50 pneumatic cylinders PER YEAR to operate fly ash hopper rotary gates (valves) was normal. The maintenance department just chalked up the expenditure to “normal maintenance” due to this very tough application.

The application requires the pneumatic conveyors, operating under the precipitators, collect the flyash and push into collection bins using compressed air. In this application, pneumatic cylinders stroke full open, and closed, every 90-120 seconds, 24 hours a day, 7 days a week. That works out to around a grueling 720 cycles per day in a dirty, hot, and abrasive environment.

Fly ash is a term used for by-products of combustion and flue gases. Nearly half of this fly ash is reused for purposes such as dry wall production and cement mixes. Because of it's abrasive qualities and high temperatures, fly ash is a difficult material to handle reliably. It's handling takes a particularly tough toll on the valves and drives that control it's movement.

A decision was made to replace the air cylinders with Rotork Type K Series AH damper drives after a visit from a local sales engineer. Along with the new drives, high-cycle “no-play” linkage kits (that eliminate hysteresis) were retro-fitted to the existing ash hopper equipment.

After five years in service, there have been no failures.  Not a single work order has been issued, no spare parts have been required, no seal kits installed and no units have been removed for servicing for any reason. Eliminating the cost of 50 air cylinders a year was quite significant, but even greater was the savings from the time and labor eliminated from their annual replacement.

For more information on this application, or on any damper drive application, visit Power Specialties at http://www.powerspecialties.com or call (816) 353-6550.