Innovation
Introduced in August 2008, the Retroflo RPC_2000 Pump Control System was designed to control pump stations as a whole, rather than just the individual components within them. Through continuous dynamic monitoring of the characteristics through a range of wet well levels and pump speeds, the system uses the full range of pumping data available to optimize performance. It can be retrofitted to existing stations or installed in new stations.
The RPC_2000 reduces a pump station's energy costs and enhances the effectiveness of variable speed operations. Keeping pumps at optimum operating conditions equates to a minimum 12 percent decrease in power usage during normal operation.
Retroflo's patented technology ensures that the required pass forward flows are maintained by using pre-blockage detection, intelligent flushing cycles and periodic efficiency testing to dramatically reduce blockages and optimize pump performance.
Blockages are a common, costly problem at wastewater pumping stations due to the gradual buildup of debris on pump impellers. This is particularly true at stations operating variable speed drives installed for energy conservation purposes.
The capability of a pump for handling solids is greatest when operating close to its maximum speed. Consequently, when VSDs are used to control sewage pumps through a range of speeds, the pumps pick up debris that affects performance and efficiency and inevitably leads to complete pump blockage. More regular interventions are required to clear blockages. Maintenance costs increase and operator confidence is reduced.
Retroflo's RPC_2000 uses its patented pre-blockage detection function to detect debris buildup and remedy the problem before it becomes a blockage.
The buildup of solids around the pump volute increases the risk of pump blockages and is another common problem at pumping stations. RPC_2000's intelligent flushing cycle uses historical operating data to predict the incoming flow rate, allowing the well to fill to a preset level before initiating a rapid well-emptying sequence. The benefits include dilution of settled solids in the well and the rapid emptying of the well, ensuring self-cleansing velocities are generated in the rising main.
End User Testimony
During the first 12 month period from installation of the Retroflo system at Northumbrian Water's Skinningrove Sewage Pumping Station, in excess of 1,000 successful pre-blockage detection routines were implemented, all of which returned the pumps to optimum performance. No operator/maintenance intervention was required to remove pump blockages.
The introduction of the Retroflo pump control system has not just maintained consents through reduction of blockages but also dramatically reduced energy costs for the station. By initiating pump reversal cycles on detection of partial blockages and returning the pump to optimum operating conditions, the improved pump performance equates to a 12 percent decrease in power during normal operation.
"Northumbrian Water (NWL) has over 800 pumping stations, many inherited from local authorities, and we undertook a process of identifying what work needed to be done through asset surveys," said Bob Dixon, product manager of Northumbrian Water. "The biggest issues identified were blockages. Prior to installing the Retroflo system in our Red Row Pumping station, we had hoped for a reduction in blockages. Actually, we have virtually eliminated blockages."
Pumps & Systems, December 2009