Kidney loop filtration on final drive


Recently a customer approached us with concerns of high particle counts in their final drive sos oil sampling. These guys are running 789 Cat dump trucks and high particle count is a sure fire way to severely limit life of these final drives.

With carbon running as high as xxx in some tests a solution was required urgently to remove this. Like most businesses in the mining industry at the moment cost was a major factor. Not only cost of a failed final drive but also implementation of a suitable filtration system and ongoing costs associated with that.

Using the KISS (keep it simple stupid) method we installed a simple kidney loop filtration system. When using a kidney loop type system, which only filters a small amount of the total flow but uses a high efficiency filter to remove as many contaminants in the most efficient way. We were trying to get the micron count down as low as we could so we went for a 1 micron, 99% efficient filter. (it will remove 99% off particles larger than 1 micron). See blog post here [insert link to blog on microns] for a detailed micron explanation.

We had some concerns about removing too much from the oil using such an efficient filter. Lubricant companies were contacted and although met with some scepticism about how it might work we pushed ahead and installed the system.

Once plumbed in we played the waiting game while the truck cycled through 2 service intervals. SOS tests were sent off after 500 hours and the results that came back were very pleasing to fleet management!

Particle analysis indicators had dropped to their best levels ever.

  • >14 micron down from 1262 ppm to 8 ppm
  • >6 micron down from 37538 ppm to 882 ppm
  • >4 micron down from 72652 ppm to 27513 ppm
  • Iron down from 32 ppm to 2 ppm
  • Copper down from 4 ppm to <1

While we like to remove everything that can cause damage to critical components. We don’t want to remove additives in the oil that are there for a purpose. Fluid characteristics remain stable and not out of tolerances.

As anyone that has done oil sampling before knows that you don’t get too many samples back that don’t have any recommendations, the first service interval reported a clean bill of health and no recommendations, just keep doing what you are doing.

In terms of return on investment, total system cost (not including labour) was under $500. Less than 4 hours to install the system.

Component life roi is hard to put a number on, previous condition, associated component failures are all factors. In terms of the sampling results we believe we are on the right track to give us every chance of increased availability, component hours and lower costs. Which is what every maintenance schedule strives for.

Sometimes it doesn’t take a high tech solution to solve problems. Management had quotes of over $5000 to solve the same problem and although those systems may well have done the same job sometimes overkill can be a killer. Know your end goal and focus on solving that first, dont complicate it and execute it.

{UPDATE}

The managers of the fleet have now rolled out this filtration system to 4 more of their fleet after the outstanding success with the initial trial. The sampling results on all of the trucks are returning very similar results as the first truck.