Pumps are at the heart of most industrial processes, and the second most common machine in the world. Because they are so common, pumps are often overlooked as a potential source of improved productivity, or a cause of excess costs if not operated properly. Plant managers, maintenance engineers and production supervisors should adhere to best practices and understand the operational do’s and don’ts for employing pumps properly in manufacturing and industrial applications. This white paper provides an overview of how to operate pumps properly and the performance parameters that need to be monitored in a preventive or predictive monitoring program. It also describes continuous monitoring systems, with several case studies on how they can be applied to improve system performance and reduce maintenance costs.
According to the U.S. Department of Energy’s 2002 Industrial Electric Motor Systems Market Opportunities Assessment, process pumps account for 25 percent of total motor system energy in manufacturing today. That makes the pump the second most common electronic machine after the motor. Though the performance of process pumps has improved with enhancements to design, materials, and the emerging use of digital technology to monitor performance, the basic structure has changed little in decades.
A centrifugal pump is a rotating machine comprised of six main parts that work together to keep the pump operating properly. They include an impeller, a pump casing, bearings, a bearing frame, a shaft, and a mechanical seal. The operating principle of the pump is to convert mechanical energy to pressure. In operation, a rotating impeller accelerates a liquid and as the area of the pump casing expands the velocity of the fluid is converted to pressure. As a result pressurized fluid exits the pump discharge.
Pump monitoring and maintenance
In the ideal world, all pumps would be properly sized to run constantly at their best efficiency points. In the real world of an industrial plant, this is impractical because processes are fluid both literally and figuratively.
Formulations change and production rates vary, but typically the hundreds if not thousands of pumps supporting process do not change with them. The solution to maintaining reliable pump operations is a robust maintenance program that combines monitoring basic machine health data in addition to pump operating conditions.
There are four areas that should be incorporated in a pump maintenance program.
- Pump performance monitoring and pump system analysis
- Vibration monitoring
- Bearing temperature
- Visual inspections
Individually, each of these is important indicators; collectively, they provide a complete pictureas to the actual condition of the pump.