DAILY TIPS

Water contamination can be harmful to engine and engine oils.
Some common problems that occur are:

• Causes corrosion/rust
• Can impair the lubricant film
• Forms sludge
• Adversely effects additives

When calcium is detected in an engine crankcase oil, the
detergent additive (calcium sulfonate) is the most common
reason.

Some elastomers that are compatible with phosphate esters
include:

• Ethylene propylene (EPM, EPDM, EPR)
• Polyamide (Nylon)
• Polyethylene

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Today we are going to look at another excerpt from Heinz Bloch's new book "Practical Lubrication for Industrial Facilities." This passage is about water contamination:

"For corrosion to occur, water must be present. Free water, in particular, will settle on machinery surfaces and will displace any protective surface oil film, finally corroding the surface. Emulsified water and dissolved water may vaporize due to frictional heat generated as the lube oil passes through bearings. Very often, though, the water vapors recondense in colder pockets of the lube oil systems. Once recondensed, the free water continues to work away at rusting or corroding the system.

"Larger particles generated by corrosion slough off the base metal surface and tend to grind down in the various components making up the lube system, i.e. pumps, bearings, control valves, and piping. The mixing of corrosion products with free and emulsified water in the system results in sludge formation which, in turn, can cause catastrophic machinery failures. Suffice it to relate just one of many examples of water-related damage to major machinery.

"When a steam turbine at a medium-sized U.S. refinery failed catastrophically, the initial problem was attributed to coupling distress and severe unbalance vibration. When the coupling bolts sheared, the steam turbine was instantly unloaded and the resulting over-speed condition activated a solenoid dump valve. Although the oil-pressurized side of the trip piston was thus rapidly depressurized, the piston stem refused to move and the turbine rotor sped up and disintegrated. The root cause of the failure to trip was found to be water contamination of the turbine control oil. Corrosion products had lodged in the trip cylinder and, although enveloped in control oil, the compression spring pushing on the trip piston had been weakened by the presence of water."

DAILY TIPS

When selecting lubricants, keep in mind advantages and
disadvantages of synthetic lubricants:

Possible Advantages:

• Increased oxidative life
• Improved lubricity
• Fire-resistance
• Thermal resistance
• Extended drain intervals

Possible Disadvantages:

• High purchase cost
• High disposal cost
• Seal or coating incompatibility
• Possible mineral oil incompatibility
• Potential toxicity

Changes in an oil's TBN (Total Base Number) can be caused by
several things:

• High sulfur fuel
• Fuel dilution
• Poor combustion
• Excessive blow-by
• Soot contamination
• Oxidation
• Extended drains
• Wrong oil
• Glycol dilution

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Here's an excerpt from Darren Nowicki's Practicing Oil
Analysis '99 Conference presentation entitled "Controlling Contamination in Hydraulic and Lubricating Fluids." This passage is about filter construction:

FILTER CONSTRUCTION

"Filters can be classified into two general categories: component protection and wear control filters. Component protection filters provide specific protection of critical components and are positioned directly upstream of the component. These are often non-bypass type filters with elements that can withstand high differential pressures without loss of integrity.

"Wear control filters are designed to control clearance size particles to reduce wear and maintain the specified fluid cleanliness level. These filters typically contain bypass valves and are located in the pressure or return line where they would see the majority of system flow. Pressure line filters have the advantage of providing both wear control and protection of components downstream of the filter. Return line filters remove ingressed and wear-generated particles thereby protecting the system from contamination, but being down-stream of critical components are not typically used as component protection filters. They do however protect the system pump from material that would otherwise be carried to the reservoir and into the suction side of the pump.

"Additional filter types include off-line filters which are used to supplement the efforts of existing in-line filters, particularly when the system flow rate is not sufficient for effective wear control. Also, air breather filters that remove particulates from the air in conjunction with wear control and/or component protection filters are an effective way to reduce ingression from external sources."