Keeping particulate filters clean

Diesel particulate filters (DPFs) are designed to clean themselves through a two-step regeneration process but when significant amounts of ash have collected, an alert light on the cab dashboard should tell the operator to stop for service.

This may occur beyond the 3,000- or 5,000-hour EPA minimum.

During the cleaning, the filter should be thoroughly inspected to determine whether it can be cleaned or has become defective and needs to be scrapped. The cleaning process begins by subjecting the DPF to pin-gauging and air-flow testing. This determines how plugged the filter has become.

At this stage, It will then either undergo thermal or pneumatic cleaning, or both. After cleaning is complete, the filter should be retested with the pin-gauging technique to measure the cleaning results.

Eliminate contaminants and extend machine life. Particle contamination is as equally destructive to a fleet of machines as moisture contamination.

Corrective action usually involves an expensive, messy, time-consuming cleanup process that doesn’t even guarantee success. But there’s an alternative: a portable oil-filtration system that  will trap the smallest of particles and clean the oil at a fraction of the cost.

Use portable oil-filtration systems:

• To salvage contaminated oil
• To clean the machine after catastrophic failure (flush first)
• To evacuate oil from a system
• To clean a system contaminated by attachments
• To extend the life of hydraulic oil

Not all oil can be cleaned. When a system has severe moisture contamination, a portable filtration system will alert the operator when the water-saturation level has hit 75 per cent and the oil must be replaced.

The thick and thin of oil viscosity

When oil viscosity test results are abnormal, chances are something else is wrong in the system or engine.

Factors can include:

• Fluid dilution of water, fuel, or coolant, or the addition of incorrect oil
• Contamination from soot, sludge, or additives
• Operating temperature colder or warmer than typical or recommended operating conditions
• Oxidation when oxygen from water, air, or contaminants attaches to the oil, thickens, and forms deposits (sludge)
• Oil moving through a pump or motor system, or exposed to high heat, causing the molecular units to break or cut (shear), lowering the viscosity, and thinning the oil

Be sure to perform frequent oil sampling relative to machine-usage hours and oil type to see if abnormal viscosity, is alerting you to a problem. 

Information for this article provided by Hitachi.