PUMPS
Metso says that the performance of the HR slurry pumps at India’ s Jindal SAW has far exceeded the owner’ s expectations
eliminate wear problems caused by the highsilica slurry. The other option was to replace all the pumps with another make, which would have been a huge cost for JSL.”
“ Following our recommendations of changing the metal casing with rubber casing, resulted in enhanced life of the pump, saving JSL considerable amount of money. We see product development as a vital part of the work in which a supplier focuses on ways to help customers increase the uptime of their processes and extend the wear life of critical components. And it is especially valuable if your supplying partner can consider and present various options that enable customers to choose the one best suited to reach their desired targets.”
Metso says the performance of the HR slurry pumps has far exceeded the owner’ s expectations.“ Because details matter, the solution selected provided JSL with increased uptime, much longer component life and cut more than 50 % in operational costs over the lifetime of their pumps. A bond of trust was established during the process, thanks to our proactive ability to offer the plant a range of effective options and solutions. As proof of this trust, JSL has decided to rely on expertise, advanced technology and innovative solutions for future expansion projects.”
However, KSB company GIW Industries points out that the only way to achieve these benefits is to ensure you’ re operating your series of pumps properly. This is particularly true during startup.“ Although your maintenance manual will serve as a guide on the best way to start up your specific pump, you should keep some special considerations in mind when operating an entire line of pumps.” When you’ re operating multiple pumps in a series, GIW advises consideration of the following factors: n Pressure and flow rate— Longer, multi-pump pipelines produce higher pressure at the last stage due to a lack of pressure drop along the line from fluid flow. When this is the case, pumps should be started one at a time, starting with the first pump in the line and moving to the subsequent pumps as the flow rate increases. n Variable speed drive— If you have a variable speed drive, you can start your pumps together at once. It’ s important to start pumps at reduced speeds to keep pressures low as their discharge valves open and the system normalises. n Discharge valve— If you don’ t have valves on your discharge side, their absence can lead to a significant power draw during startup. Account for this in your drive equipment, which must be able to handle the magnitude and duration of the power surge during each startup.
“ Ignoring any of these factors can lead to a host of problems, ranging from damaging pressure surges to electrical failures, cavitation, and high wear on your pump parts and system equipment. Not only are these issues costly and time-consuming to correct but they can also pose risks to those working nearby. That’ s why it’ s vital to have the right equipment in your series and employ the right startup procedures for your unique system and application. Often, this means turning to professionals who can take a closer look at your specific setup. If you’ re plagued with startup or wear issues, an analysis of the transient startup behaviour, pump and drive train assessment, water hammer analysis, or pump analysis may be in order.” Once you’ ve verified the appropriate procedures for your slurry line, GIW advises using this customised checklist along with the basic startup steps to increase the efficiencies of your entire system: n Make sure the suction piping is clear of debris n Ensure the suction valve is fully open n Once the pump reaches full rotational speed, open the discharge valve slowly n Monitor the startup strainer to make sure the inlet pressure is adequate“ With a little knowledge— and some expert guidance— you can start up multiple pumps in a series quickly, simply, and safely.”
Another important topic addressed by GIW in a recent article is cavitation.“ From a technical standpoint, cavitation occurs when the absolute pressure at the eye of the impeller reaches the vapor pressure. At this pressure, bubbles or‘ cavities’ form in the liquid. As the bubbles move from the low-pressure area near the impeller toward the high-pressure area surrounding the pump discharge, they implode. These little implosions of collapsing bubbles cause loud popping noises, which operators can hear
GIW advice on multiple pumps and cavitation
Whether you’ re moving tailings a long distance or working in a demanding mill circuit application, chances are good you’ ll be relying on more than one pump to get the job done. Installing a series of slurry pumps can eradicate high flow and high head issues, and it also allows you to operate at a lower speed, thus, reducing wear on the entire system.
Longer, multi-pump pipelines produce higher pressure at the last stage due to a lack of pressure drop along the line from fluid flow. When this is the case, GIW advises that pumps should be started one at a time
44 International Mining | JUNE 2018