DuPont™ Vespel® CR-6100 Wear Rings
Switching to Vespel® CR-6100 may seem like a small change, but it can offer big results. After making this change with Boulden Company, a fertilizer plant in Canada eliminated pump seizures, was able to run at full capacity with one pump, could save their second pump for 100% spare capacity and saved over $30,000 in one year, which paid for the upgrade in just months.
How Does A Boiler Feedwater Pump Work?
A boiler feed water pump is a pump that is specifically designed to pump feed water into a steam boiler. The water may be supplied by an outside source or be returning, recycled condensate that is produced via the condensation of steam generated by the boiler. Most boiler feedwater pumps are either centrifugal pumps or positive displacement pumps.
Because of the steam pressure that develops within the boiler, the boiler feed water pump must generate extremely high pressure in order to force water into the system. For boiler feedwater pumps that run constantly, a minimum flow device is usually provided to prevent overpressuring during low flow, retuning the minimum flow to the boiler’s tank or deaerator.
Building a Better Boiler Feed Pump with Vespel® CR-6100:
A fertilizer plant in Canada installed 2 boiler feed pumps. They were originally sized to run with one pump with a 100% capacity spare in stand-by. Soon after start-up, however, the pumps experienced problems:
- Seizure at the wear rings. In order to run reliably, the clearance at the wear rings was increased from 0.016” (0.40 mm) to 0.020” (0.50 mm)
- Increased wear ring clearance lead to reduced output capacity and the need to run both pumps in parallel
- Running both pumps created a risk of reduced boiler capacity whenever a pump was shut down and resulted in large energy losses
What they did:
- Upgraded case rings, throttle bushing, and center-stage bushing to Vespel® CR-6100
- Reduced the clearance at the wear components to 0.008” (0.20 mm)
- Verified concentricity of the rotor and quality of all fits through good repair procedures
Results of adding Vespel® CR-6100:
- Pump seizures were eliminated
- The plant could run at full capacity with 1 pump, regaining 100% spare capacity and superior plant availability
- Changing from 2-pump operation to 1-pump operation saved over $30,000/year in power, paying for the upgrade in a matter of months