Frequently Asked Questions

Q: If I have a viscous liquid (over 150 cSt), which type of pump is better?
Answer: Positive displacement (PD) pumps are more efficient than centrifugal pumps, and in particular, Blackmer’s sliding vane pump technology provides excellent results with high viscosity fluids.

Q: What is LCC?
Answer: Life Cycle Costs, which include initial cost, energy cost over time, and long term costs associated with maintenance and down time.

Q: Why does my pump consume more energy than it did when I first installed it?
Answer: Loss of efficiency over time is common with standard positive displacement pumps. Degradation occurs when the parts wear and clearances increase, resulting in a loss of pumping capacity. However, sliding vane pumps have self-adjusting vanes, which continue to maintain near-normal efficiency and capacity throughout the life of the vanes.

Q: Any idea why I am noticing excessive pump vibration, pressure and heat?
Answer: Undersized pipes (or oversized pumps) are a very common cause of unstable hydraulics, cavitation vibration and over-amping.

Q: I’m concerned about down time for pump maintenance. Which pump is going to reduce off line maintenance time?
Answer: Sliding vane pumps have self-adjusting vanes, which minimize energy-robbing slippage and maintain efficiency by reducing capacity loss. Vane replacement is comparatively simple compared to centrifugal and gear pump rebuilding.

Q: Which pump is more efficient with increasing pressure or viscosity?
Answer: Efficiency in positive displacement pumps increases with increased pressure and viscosity.

Q: What are the various types of Positive Displacement (PD) pumps?
Answer: There are many kinds of PD pumps, both rotary and reciprocating. The most common rotary include Sliding Vane, Gear, Lobe and Screw pumps. The most common reciprocating positive displacement design is Air-Operated Diaphragm pump.

Q: What are the various types of Kinetic (Dynamic) pumps?
Answer: The most common type of Kinetic (Dynamic) pump is Centrifugal which includes many different designs. Also included are Regenerative Turbine and Special Effect pumps.

Q: Why is my pump losing efficiency and flow since installation?
Answer: Gear, lobe and centrifugal pumps all suffer from internal wear, resulting in clearance degradation and inefficient performance.

Q: Of all Positive Displacement (PD) pumps, which is most energy efficient?
Answer: Of the leading Positive Displacement pump technologies, sliding vane pumps are generally the most energy efficient.

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