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In This Issue:

• Up Front: Double-check of Lube Specification Saves the Day

• Book Bits: How Water Affects Lubricant Additives

• Today's Tip: Antifreeze Caution for Diesel Engine Owners

• Q & A: Antiscuff in Moderation
  

Up Front

Double-check of Lube Specification Saves the Day

An important component of the safety systems at the Ontario Power Generation facility in Pickering, Canada is the standby generator. While preparing a plan to flush and refill the power turbine, it was discovered that the Procurement Department had inserted a "No Purchase" comment in the CMMS system associated with the ISO VG 32 turbine oil usually used, recommending instead that a different, less expensive product be used.

After researching the two products, it was found that the original product was formulated from a Group II basestock, while the less expensive product was a Group I. The Group I basestock oil has a higher cloud point (indicating a less refined product with greater wax content). In the past, usage of this product had caused equipment problems in cold-start situations. Cold oil in the coolers had a tendency to cause large pressure drops across the filters, resulting in low oil pressure trips of the emergency shut-down system. This is why the Group II was used in this application.

Fortunately, the Procurement Departments error was identified before the inferior product was introduced to the equipment, and therefore no damage occurred.

A quick call to the Procurement Department reminded them that price differences shouldn't be used as the primary criteria for selecting lubricants.

Submitted by Khalid Malik, Technical Engineer/Officer, Ontario Power Generation. Thanks Khalid!)

Each Up Front story published will earn the sender $50. To submit a case study, experience or lesson learned click here or e-mail info@noria.com.

Book Bits

How Water Affects Additives

From "Fluid Contamination Control":

Water in tribological fluids (other than water-based fluids) leads to a multitude of problems in terms of system damage and failure. Perhaps the worst threat of water contamination in storage is its reaction with additives and the damaging reaction products.

Moisture causes a filter-clogging slime to form in fluids containing tricresyl phosphate (TCP), an antiwear additive used in tribological fluids where an alkali is present. If ZDDP (zinc dialkyl dithiophosphate) is used as the antiwear additive instead of TCP, many deteriorating mechanisms could exist; suffice to state here that ZDDP can decompose to form hydrogen sulfide and, in the presence of moisture, transform into a highly corrosive acid (sulfuric acid). Even in fluids of the corrosion-prevention type, moisture causes an egg-white type slime. According to T.N. Dean, when moisture is present, corrosion-preventive additives can exhaust themselves by "wrapping up" the moisture in additive and water dispersion.

Click here for more information about "Fluid Contamination Control".

Today's Tip

• When changing pillow block bearings with a cylindrical OD on the outer race, be sure to clean the grease channel located in the housing prior to installation of the new bearing. The grease in the channel tends to attract dust and dirt over time. When the bearing is changed, this dirt can become displaced into the grease channel as the new bearing is tipped into the housing. The dirt can either pass through the application hole in the outer bearing race or plug off the hole, resulting in damage to the new bearing. (Tip submitted by Greg Neuenfeldt, Dow Corning. Thanks Greg!)

• Editors Note: Regarding last week's tip about using spin-on filters as air breather filters on reservoirs and gearboxes:

  If you plan to use automotive spin-on filters for breathers, drill holes in the base of the filter outside of the gasket area. Automotive filters have a built-in anti-drainback valve that won't let air out unless these holes are drilled.

  Normal industrial filters, like those used in hydraulic applications and filter carts, etc., don't require holes to be drilled.

Each tip published will earn the sender $25. Click here to submit your tip.

Q & A

Antiscuff in Moderation

"Why aren't all lubricants formulated with anti-wear additives?"

Lubricating oils should be carefully selected for specific applications and not haphazardly applied. The dominant wear mechanism and environmental contaminants and hazards that are expected or known to occur in a piece of equipment should be known and countered by an effectively designed lubricant formulation including base oil type, viscosity, and additive package.

Heavily loaded components should be protected first by viscosity if possible, and antiwear or mild to heavy extreme pressure properties as needed. These additive packages all protect equipment from rapid mechanical wear at the cost of inducing some amount of chemical wear, relative to the aggressiveness (strength) of the antiscuff package. In lighter load situations, an over-aggressive lubricant can shorten equipment life through corrosive attack without providing any useful benefit.

Note that some synthetic basestocks (such as diesters) have some limited natural antiwear properties without causing surface degradation, and that some lubricity agents found in compounded oils are nonchemically reactive.

Adam Davis, Technical Consultant, Noria Corporation