Embedded processor runs this VFD pump

In conjunction with a VFD and software, there's a relatively new pumping system that the manufacturer, Goulds Pumps, claims will save enormous bucks. The software is proprietary and resides on the controller microprocessor chip. It enables the pump to monitor and react to any system fluctuation.

Designing a heavier-duty pump does not directly translate to a longer-life pump. The primary culprits in pump failures are seals and bearings. Failures happen at those critical spots because of excessive vibration, excessive loads, and poor lubrication. These failures are caused primarily by the following factors:

• Dry running (usually because of closed suction valves)
• Continuous operation below minimum flow
• Cavitation due to insufficient net positive suction head available
• Heat buildup and subsequent liquid vaporization due to a closed discharge valve.

The Goulds system, which the company calls PumpSmart, detects these hazards prior to the upset condition occurring and prevents the pump from operating during these transient conditions. The pump will react by stopping, slowing down, alarming, or any combination of these actions, depending on how a plant wants to program the unit.

The pump continuously monitors the system, detects when the transient condition passes, and then resumes normal operation. The pump runs at a slower speed, at or close to best efficiency and at a reduced impeller diameter. The initial capital costs benefit from the following:

• Flow control valve piping and wiring (plant air, power, and communications lines) costs disappear (costs to run and maintain plant air can also be avoided for pneumatic valves).
• External flowmeter piping and wiring (power and communication lines) costs are eliminated.
• The controller replaces the starter so the installation cost of the starter is replaced by the cost to install the microprocessed system.

The biggest dollar savings over the life cycle of this scheme, the manufacturer said, is that realized by reduced energy use. That's because VFD controller and software match pump operation to the system head requirements, which eliminates the need for energy consuming control valves.