Yorkshire Water is one of the principal water and waste water treatment companies in the UK and had a problem with a lime dosing application at the Ruswarp Water Treatment Works near Whitby,
Lime dosing is a classical Verderflex® application with many installations in the water industry and the following is a very successful installation by Verder UK’s sales team, which addressed the problems of an abrasive variable viscosity product causing excessive pump downtime and continuously high maintenance costs.
Originally, classical solenoid driven diaphragm pumps were being
used to dose Kalic® Liquid Lime, a viscous, alkali solution added to the water supply to maintain a neutral pH value. The problem occurred when these pumps had to operate at low flow rates.
Staff were constantly called out after the pumps became clogged with the viscous product and failed. As a solution, Verder recommended the replacement of these units with Verderflex® peristaltic pumps.
Pumps in this range can self-prime to a depth of 9.5m and are engineered to prevent clogging. They can handle highly viscous liquids and offer precise flow control, making them ideal for dosing applications such as this. They are also easy to maintain, as the hose is the only part of the pump that comes into contact with the product.
Five Verderflex® pumps have subsequently been installed at
the site by Verder UK, under the instruction of the consulting
engineers Earth Tech/Morrison. These include two VF15’s for pre
Kalic and two VF10’s for post Kalic dosing. A VF25 re-circulates
the solution to storage tanks. The new pumps are controlled by the
site’s PLC and utilise the existing inverters to give variable speed and flow as required. This system has replaced the twin controls for speed and stroke adjustment that were fitted with the diaphragm pumps.
The installation was carried out without interrupting the water
supply and no call outs have been experienced, dramatically reducing
both downtime and maintenance costs.