These pumps prevent equipment from corroding, provide lower costs and increase efficiency.
by John A. Kozel (Sims Pump Valve Company, Inc.)
August 19, 2015

Improved Efficiency

In 2015, tremendous effort has been put forth to reduce energy consumption. The Department of Energy (DOE) and the Hydraulic Institute have been working together to reduce the energy consumption of pumps, motors and pump systems. Engineered composites can contribute to this effort. By re-engineering the pump/impeller design, they can significantly reduce energy consumption—in some cases by 20 percent.

Damage from corrosion, erosion and cavitation can quickly destroy metallic pumps and pump parts.Image 3. Damage from corrosion, erosion and cavitation can quickly destroy metallic pumps and pump parts.

Equipment Longevity

In addition to improved efficiency, engineered composite impellers offer many advantages over traditional products cast from metal. They do not corrode, are lightweight, can run with tighter clearances, are designed for high efficiency, and are not subject to casting defects or imperfections. Many of these impellers and casing rings have been used successfully since 1955 in the Marine, Navy, wastewater, industrial and chemical markets. Structural composite impellers have often outlasted and outperformed products manufactured from bronze, stainless steel, duplex steel, monel and even titanium.

Reduced Wear

The new alternative composite solutions for impellers and rings are ideal for new, repair or retrofit applications. Engineered impellers and rings are lightweight and do not corrode.

This composite pump was re-engineered into a two-stage structural composite pump with single-suction impellers.Image 4. This composite pump was re-engineered into a two-stage structural composite pump with single-suction impellers. It is approximately 11 percent more efficient than the original metallic pump (before corroding).

Wear of other pump parts—including the pump casing—is greatly reduced because of the engineered impeller's balance, light weight, self-lubrication, sealing, and resistance to corrosion, erosion and cavitation. This means far less expense for replacement of parts and downtime. Reducing or eliminating corrosion, erosion and cavitation can increase efficiency and reduce costs substantially.

Maximized Performance

Because of new technologies, structural composite impellers are computer-engineered and precision-machined. The impeller vane geometry can be engineered using computational fluid dynamics (CFD) techniques and programmed to maximize efficiency and performance. Problems such as recirculation, radial thrust and cavitation can be minimized or eliminated by using structural composite impellers instead of the traditional metallic ones. Impeller vane shapes can easily be modified to provide the best vane shape for specific applications and performance requests.

This vertical in-line structural graphite composite pump replaced the type 316 stainless steel pumps onboard the Navy Military Sea Lift Command Vessel.Image 5. This vertical in-line structural graphite composite pump replaced the type 316 stainless steel pumps onboard the Navy Military Sea Lift Command Vessel.

Corrosion, erosion, cavitation, rotor imbalance and leakage between the wear rings, casing rings and interstage bushings are major contributors to the loss of pump efficiency. Damage from corrosion, erosion and cavitation quickly destroys the metallic pump parts. Because of the self-lubricating characteristics of many engineered composites and because composites do not wear or corrode, the performance curve will actually increase over a period of time. A 1,000-hour performance test was completed on a U.S. Navy Standard Fire Pump manufactured from titanium with one company's engineered structural composite impeller and casing rings. The result showed a 2.5 percent increase in the head-capacity (H-Q) at the end of the test.

One of the many advantages of using composite pumps is that the casing volute geometries and the impeller geometries can be designed and engineered specifically for the required operating point in the plant or vessel. With premium efficiency engineered structural composite pumps, strength can be added and removed based on need.

Premium efficiency composite pumps are designed and engineered to keep their overall sizes at a minimum so that they can easily fit into confined spaces. These types of pumps are also engineered to minimize piping modifications while maintaining or exceeding pump performance. These engineered composite equipment upgrades help pump users increase the efficiency and longevity of their pumping systems.

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