5 Reasons Your Pump Might Be Running Inefficiently
A pump’s performance curve, which is included in the documentation provided by the manufacturer, allows you to measure your pump’s performance, including energy, flow and pressure that it should be providing under a specific set of circumstances. If your pump is running, but not operating at peak efficiency, the excessive energy required will cost you money – sometimes more than the initial cost of the pump! So, what could cause your pump to run inefficiently?
1. Oversized pump
It is essential to select the right sized pump for the application – yet many engineers choose pumps that generate more flow and head than the application requires. Over time the pumped fluid will cause the casing and impeller to deteriorate and the worn pump will eventually operate within an acceptable performance range. However, the pump discharge must be throttled until the wear occurs, which is waste of energy. If an engineer were to choose a smaller pump, which has a protective coating to minimise the effects of corrosion and erosion, they would be able to save on this loss of energy.
Many issues can also occur if the pump remains the same but the design point changes, such as increased energy costs and cavitation.
2. Motor wired incorrectly
If the motor is wired incorrectly, the motor can cause the pump shaft to rotate counter to its required direction – indicated on the pump’s bearing frame. While the pump will still run, it will run at a fraction of the flow and head indicated by the performance curve. If you find that your pump is not generating the rate of flow expected, check that the shaft is rotating in the right direction.
3. Degraded bearings or contaminated lubricant
If a bearing is failing it causes a drag on the motor, requiring more current to rotate at the designed speed – thus costing more energy to get the correct flow. So although your pump may generate the specified flow and pressure, more energy is required to rotate the shaft.
Washing down industrial pumps can also cause bearing lubricant to become contaminated – eventually degrading the bearing. Protecting bearings from degrading and bearing lubricants from moisture is critical in maintaining the reliability and efficiency of your pump.
4. Eroded or corroded impeller and casing
The shape of the impeller and its casing are critical for the correct functioning of the pump, affecting its ability to impart energy to the fluid. Erosion, corrosion and instances where solids in the fluid flow at high speed can change the shape of the impeller and/or its casing – affecting the efficiency of the pump over time. Although pumps are designed with an allowance for corrosion, anything beyond these limits can affect the efficiency of the equipment. If possible, choose pumps which are made of corrosion and erosion resistant materials, contain enclosed impellers and wear rings, or which offer hard casing, protective materials for the impeller, or rubber linings to prevent erosion.
Clogged filters or strainers, blockages in the pipe, or poor piping design can lead to cavitation – which is usually indicated by a popping sound. Pump cavitation can lead to excess energy use and severe issues for your pump system, such as damage to the impeller and/or the pump housing and decreased flow and/or pressure. The excessive vibration can also lead to early seal and bearing failure if left untreated. Check for clogged filters or strainers or blockages in the pipe, or if the pump is running too far right on the pump curve (suction cavitation) or too far left (discharge cavitation).
If you’d like more information, please call our toll-free number 1-800- 367-4180. We have experts on hand to help you choose, install, and maintain a variety of equipment.