The New Braunfels, Texas plant of the Canyon Regional Water Authority is keen on sourcing an alternative to its progressive cavity (PC) pump to increase the accuracy of pH control. The potable water plant currently controls pH by dosing lime slurry using a PC pump, which runs for approximately 12-16 hours a day at a rate of 900 litres/hour.
Watson-Marlow has supplied a Bredel APEX35 hose pump to the New Braunfels CRWA plant so that engineers can see the benefits of using a hose pump to handle the lime slurry. First of all, insufficient flow consistency of the PC pump is prone to causing fluctuations in the pH control, which means variations in water quality. Installation of the APEX35 hose pump with its stable and consistent flow means that these problems have already been eliminated.
Another practical advantage of this new hose pump at the site is reduction in maintenance. The abrasive nature of the lime slurry means that maintenance is required on the PC pump every three months and takes up to five hours to complete. Furthermore, this often requires expensive consumables such as stators, rotors or linings. In contrast, the APEX35 pump has required no maintenance in its first six months of operation at CRWA, and when maintenance is finally required, it will take no more than 30 minutes, with the only consumable part being a single hose element.
The success of the CRWA APEX pump trial was replicated at the plant of Addenda Corporation, which is in the process of comparing its existing hose pump to a new Bredel APEX35. Here the task involves the accurate transfer of a very abrasive, high solids, lead-based slurry between process stages. The existing hose pump and the APEX35 are being run under exactly the same process conditions, with flow at approximately 2500 litre/hour.
The company’s existing pump requires hose replacement every 8-9 months; a very acceptable and cost effective uptime period. The APEX35 pumps' hose replacement significantly is not expected before 14 months running is complete. This is thanks largely to the APEX design, which is optimised for medium pressure applications and long lasting hose elements, and increase it pump uptime arrives as a consequence of selecting the right pump for the application.
When handling abrasive substances, a major advantage of APEX hose pumps is that they have no costly wearing components like seals, valves, membranes, stators, rotors or glands to maintain. Self-priming, dry running, and with no internal valves, hose pump technology also helps users improve their processes by eliminating troublesome ancillary items like anti-siphon valves, back-pressure valves, degassing valves or run-dry protection.
Consequently, APEX hose pumps are perfectly suited for transfer and metering abrasive, corrosive, viscous, shear-sensitive, gaseous, crystallising fluids, or even fluids with a combination of these properties.
Another important factor in being able to reduce maintenance costs at Addenda is that the APEX35 requires 18% less hose compressions for the same volume transferred by the existing hose pump (which needs around 1500 strokes for each 1000 litres). What’s more, the direct coupled technology and self-supporting rotor on the APEX35 help maximise gearbox and bearing life to further add to the package of savings for the plant.