Book Bits

From "Filtration Technology":

Fuel Contamination Particulates

Diesel fuel contaminants include abrasive dust, water droplets and organic materials such as lint and rust. Field dust, particles of grass and leaves, etc., are an added contamination factor in agriculture and earth moving environments. 98% by weight of common dust is composed of silica or quartz, which is very abrasive. Abrasive particles can cause damage as indicated in the sections on transfer pumps and fuel injection systems.

The most damaging particles for most injection systems are in the 7 to 15 micrometer particle size, even though the critical clearances are between one and three micrometers. The reason for this is that while the edges of the metering ports and grooves appear sharp, they are actually bellmouthed. Particles of quartz that are 10 to 12 micrometers in size can get trapped in these areas and as the operating pressure drives them into the clearance spaces they break down and are ground smaller. (One 10-micrometer cube-shaped particle contains the equivalent of 1000 one-micrometer particles.)

Click here for more information about Filtration Technology.

Today's Tip

• In a humid environment, condensate can form in rolling element bearings and cause corrosion, leading to a reduction of the bearing life. With careful choice of the grease lubricant the effect of the condensed moisture can be reduced. Greases thickened with sodium soap will absorb (emulsify) large quantities of water, but may, however, soften it to such an extent that the grease flows out of the bearing. Lithium soap greases do not emulsify water, but with suitable additives can provide good protection against corrosion. There are also a number of greases available which have synthetic thickeners that offer excellent protection against corrosion, prolonging the bearing life. (Tip submitted by Derek Peasley, FAG Europe. Thanks Derek!)

Each tip published will earn the sender $10. Click here to submit your tip.

Q & A

"I am seeing steam coming out of my reservoir breather. Should this be a cause for alarm?"

Steam coming from a reservoir is typically a sign of a problem. You should first confirm whether it is a vapor or steam by placing a mirror over the breather. Fogging of the mirror generally confirms steam. This could be due to exceptionally high operating temperatures and a sudden ingress of water into the fluid.

Another problem to be concerned about is foam coming out of the vent. This is a serious condition, suggesting key properties of the oil have changed sharply. There are many causes of foam formation relating to contamination, defoamant additive, oil degradation, oil level and mixed lubricants.

Copyright © 2001, Noria Corporation. All rights reserved. Please do not reprint or host on your website without explicit permission. However, if you found this newsletter helpful, we grant you permission, and strongly encourage you, to e-mail it to a business associate or a friend. Thank you. The presence of advertising in Lube-Tips does not constitute an endorsement of the products or services in such ads. Further, because results will vary widely based on a number of factors, Noria Corporation cannot warrant the results, the accuracy or the completeness of any material published herein.

Lube-Tips is published by Noria Corporation. Oil Analysis and Lubrication Experts