January 2020

30 n VARIABLE-SPEED DRIVES January 2020 www.drivesncontrols.com Master and slave drives ensure that hospital water supply is reliable T he multi-storey Rambam Academic Hospital, located in Haifa, is the largest hospital in northern Israel and provides emergency and medical care to patients through a range of operating theatres and medical facilities. Its water system previously relied on two 22kW pumps which also supplied an emergency water tank when the mains water supply failed or was interrupted by power cuts. In an upgrade to the water system, two more Lowara pumps were installed to control and manage the supply, achieving energy savings at the same time. All four of the 22kW pumps are now controlled by VSDs, and they are allowing the hospital to manage its water system more flexibly and effectively. “When demand is low, it reduces the number of pumps required but ensures a consistent flow at all times,” explains Avi Even of Solcon Industries, which supplied the new Optidrive Eco drives made by the Welsh drives manufacturer, Invertek. “The individual pumps don’t have to be working at full capacity all the time, thus reducing the energy costs, water usage and wear-and-tear on them which, in turn, cuts maintenance costs and downtime.” The IP55-protected 22kW Optidrive Ecodrives incorporate a technology called Optiflow that provides flexible pump control. It allows several drives to work together to ensure optimised flow rates. The first drive acts as the master, with the other three acting as slaves. The master controls the speeds and run times of the slaves. The system is controlled intelligently based on demand using a PID function built into the VSDs. This ensures that the system is never under stress mechanically, thus reducing wear-and-tear and downtime. The pump output pressures are monitored continuously and sent to the master drive, which sets the on and off condition and the speeds of all the drives intelligently, using its PID and Optiflow functions. If one of the drives or pumps is out of service, operation is transferred automatically to another, ensuring that the system should never shut down completely. The drives can also detect and clear any pump blockages, thus providing protection against dry running or burst pipes. “The system means the hospital can rely on the constant and reliable water supply to all parts of the building,” Even concludes. “This ensures that medical staff and patients can be assured of a consistent water supply at all times.” n An Israeli hospital is using UK-built drives to maintain a constant and reliable supply of water. Four VSD-controlled pumps are operating in a master-and-slave configuration designed to save energy and ensure a continuous supply of vital water to all areas. The Rambam Hospital pump room now houses four inverter- controlled pumps which work together to ensure a reliable supply of water throughout the building