Plant & Works Engineering February/March 2023

Focus on: Pumps & Valves Process, Controls & Plant February/March 2023 www.pwemag.co.uk Plant & Works Engineering | 25 The savings can be determined by the affinity laws: Q= Flow, H= Head, P = Power and n = Rotational Speed When building a new pumping system, most Pumps are selected with a “safety factor” for potential future uprates or to allow for wear in the pump or fouling of the system. Often there are many different parties involved in specifying and building a system and the safety factor can grow exponentially. This results in the pump delivering much higher flows than required. There may also be the need to vary the flow due to process conditions or varying heating and cooling needs within buildings. Traditionally, throttling is used to regulate flow in a pumping system. While throttling reduces the flow, the motor is still running at full speed and works even harder as it must work against a restriction. By reducing the speed of the motor, the variable speed drive ensures no more energy than necessary is used to achieve the required flow. A centrifugal pump running at half speed consumes only one-eighth of the energy compared to one running at full speed. Utilising an Electrical Variable Speed Drive is the simplest and most economical way of controlling the pump and matching it to the pump system. When specifying a new pump, ask for a high efficiency motor to be fitted. If you are replacing or rewinding a motor, then evaluate the cost of fitting a High Efficiency motor remembering to factor in the running savings which will pay back any increase in cost. Invest in carrying out an energy audit. Review your utility bills and understand the energy you are using. Carry out an audit if: • Your energy bills are high • You have continuously operating pumps • You have many pumps in the system • You have processes with varying flows • You have throttled pumps • You have pumps which are on bypass • You have noisy valves or pipework • You have critical systems which have been subject to breakdowns The purpose of an energy audit is to reduce operating costs by reducing energy consumption and the government has estimated that most companies can reduce their energy consumption by 10% to 20%. Energy audits conducted by BPMA members have shown that savings from 30% to 50% are not unusual. When deciding whether or not to carry out an energy audit a good starting point is to assume that you will save at least 10% of your current energy consumption. By reviewing utility bills, you can get an indication of the savings to be made and the investment that you should be prepared to put into the auditing process. Across most industrial sites, some two-thirds of the total energy consumption is used to power electric motors. Furthermore, the overall cost associated with operating these essential pieces of equipment throughout their entire life span can be broken down as follows; 5% accounts for the initial purchase/installation costs, 10% for ongoing maintenance and a massive 85% for the energy used to run them. Clearly, any reduction in the energy consumed by electric motors is important, and with modern designs that reduction can be as much as 30%. It is also evident that many pumps and motors are constantly operated at full power, irrespective of process needs, and so across the installed base there is the potential for significant energy savings; savings which can in turn drop to the bottom line and increase the profitability of any business. For further information please visit: www.bpma.org.uk For more informa琀on call 0121 601 6691 , scan code for the training guide or email: training@bpma.org.uk Pump Repair & Maintenance Course Independent Pump Training from 2 day course 6 th & 7 th Dec 2022 Classroom & hands on training Held at BPMA o ces West Bromwich B70 6PY