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One of the biggest headaches for pump operators is Pump cavitation. Pump cavitation can cause significant damage to a pump’s components, reducing output, and ultimately requiring pump overhaul. One of the easiest ways to reduce pump cavitation is to switch to wear rings made from composite materials like Vespel® CR-6100 or Boulden B-Series.

What Causes Pump Cavitation?

Consider a typical case: a water pump with bronze wear rings that is experiencing cavitation damage. If it is a new installation, the most likely cause is a design issue and discussions with the EPC contractor and OEM are in order. More commonly, however, pumps cavitate due to marginal field conditions or because of worn internal components. If the cavitation is due to marginal field conditions, the pump operational range may be limited. The pump might cavitate only during higher flow rates, when it is running in parallel with another pump, or when the suction vessel level is reduced. This implies an insufficient NPSH margin—the difference between the Net Positive Suction Head Available (NPSHA) and Required (NPSHR)—for the full range of service requirements. If cavitation is due to worn internal components, the pump will begin cavitating after some time in service. This is a common problem when pumps use bronze or cast iron wear rings. Bronze is widely used in water pumps because it is inexpensive and relatively non-seizing. Unfortunately, bronze also tends to wear quite rapidly. When wear ring clearance increases, NPSHR increases, efficiency drops, and cavitation becomes more likely.

Composite Wear Ring Insert
Vespel® CR-6100 wear ring for a cooling water pump

How Vespel® CR-6100 & B-Series Wear Rings Reduce Pump Cavitation

Composite wear rings create a non-metallic interface at the close-clearance wear parts in the pump, essentially eliminating the risk of pump seizure, and allowing the internal clearance to be reduced.  Reducing wear ring clearance reduces the pump NPSHR, thereby increasing the NPSH margin in the field, and helping to avoid cavitation. Furthermore, low friction composite materials like Vespel® CR-6100 and B-Series resist wear, allowing the pump to maintain tight internal clearances for many years, increasing the time in service for your pump! Tight clearances also increase pump efficiency, reducing the cost of operation. To achieve these benefits, convert your stationary wear rings to Vespel® CR-6100 or B-Series, the rotating wear ring will remain metal, and the clearance between the rings will be reduced. It is a simple change that can be completed at your next overhaul. Boulden has the material you need in stock and can deliver raw material or machined parts with very short lead times. Visit our Vespel® CR-6100 or B-Series composite material pages for wear ring options or call us at 800-523-0569 and we will gladly assist you with your questions. Boulden is your trusted source for state-of-the-art composite centrifugal pump wear rings that help to reduce pump cavitation.

Benefits of DuPont™ Vespel® CR-6100 & B-Series to Reduce Pump Cavitation

Beyond helping reduce cavitation, using composite materials with reduced clearance makes your pumps run better:

  • Improved efficiency
  • Reduced vibration
  • Reduced risk of pump seizure
  • Easier assembly, alignment, and operation
  • Potential to survive dry running

Vespel® CR-6100

Vespel® CR-6100 is a composite material that can be used for a broad range of applications. Made from long carbon fibers and from Teflon® PFA resin, Vespel® CR-6100 resists temperatures as low as -238 F and as high as 500 F (-200 C to 260 C). It is also chemically compatible with almost all fluids. Vespel® CR-6100 parts are easy to machine and install, offering a simple, cost-effective solution for reducing pump cavitation.

B-Series Composite Materials

The B-Series is a group of materials developed and manufactured by Boulden to extend these benefits to as many of your pumps as possible. There are currently three B-Series composite materials options including B-835B-920, and B-1050. Contact Boulden and we will help determine which material is right for your application.

Reduce Pump Cavitation with Vespel® CR-6100 & B-Series Composite Materials

Longer pump life, less cavitation, decreased costs and improved efficiency are just a few of the benefits you will experience when you replace existing parts with Vespel® CR-6100 and B-Series composite materials. If you have specific questions regarding our composite wear ring options, get in touch with our sales team and we will gladly answer any questions you have regarding your specific requirements. Or sign up for our newsletter to stay up to date on Boulden’s newest offerings.

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