Pumps are used for a wide range of applications to transfer fluids through mechanical action. According to the basic operating principle, pumps can be classified as either dynamic pumps or positive displacement pumps. Dynamic pumps are further classified into centrifugal pumps and special-effect pumps. Positive displacement pumps are further classified into rotary pumps and reciprocating pumps.
Centrifugal pumps account for the major share of electricity consumption in the industrial sector. Some of the centrifugal pumps used by the industry include:
- Mono-block pumps
- Endsuction pumps
- Split-case pumps
- multistage pumps.
Efficiency of pumps can be significantly improved by following these basic guidelines
Management and control
- Operate pumps close to the best operating point as specified by the OEMs
- Use pumps with the highest efficiency to meet the base load when multiple pumps are in operation
- Install variable frequency drive (VFD) for fluctuating loads instead of throttling
- Use on-line monitoring for centralized large system and periodical measurement for decentralized smaller pumps
- Use multiple smaller pumps in parallel operation in place of single pump of higher capacity
- Manage and control the loading of pumps near the best operating point of respective characteristic curve in case of multiple pumps in operation
- Manage the piping network of the pumping system and the control operating parameters, such as flow rate, pressure, and temperature to meet process requirements
- Replace worn-out pumps with energy efficient pumps
- Maintain a minimum Net Positive Suction Head (NPSH) of pumps as prescribed by the manufacturer
Measurement and recording
- Key operating parameters such as the total differential head, flow rate, and electricity consumption to evaluate the efficiency of pumps on monthly basis
Maintenance and inspection
- Check the condition of gland sealing on daily basis and undertake maintenance to avoid leakages
- Inspect the pump for vibration and noise level on quarterly basis
- Inspect and ensure proper tension of belts for belt driven pumps
- Undertake periodical maintenance including overhauling of the pumps according to the instructions provided by the OEM
- Ensure dynamic balancing of pump assembly after each overhauling
- Calibrate instruments and gauges as per the recommendations of the suppliers to ensure reliability and maintain accuracy of data
Other recommendations
- Use a booster for small loads requiring higher pressures
- Select correct capacity of pump with energy efficient systems, such as IE3 motor or permanent magnet synchronous motor, variable frequency drives (VFDs), etc., to avoid energy wastage
- Install suction valve of proper size as recommended by OEM
- Ensure pump efficiency close to the design values provided by the OEM
- Replace rewound motors in pumps with IE3 motors