Page 218 - Boiler_Operators_Handbook,_Second_Edition

Maintenance 203

barrel of the grease guns and tip will help to ensure the protect oil in storage and en route from storage to the
proper lubricant is utilized. equipment. Many modern oils can absorb moisture and
Another problem I see regularly is a failure to clean must be kept sealed until they are put to use. If your
the grease fitting before attaching the grease gun. Use equipment contains an oil heater then the oil will prob-
of a lint free rag to wipe off the fitting is recommended ably absorb moisture right out of the air, contaminating
but it will not always remove the paint and other mate- itself if it isn’t kept in sealed containers.
rials that manage to find their way onto grease fittings Oil, unlike grease, can be cleaned and rehabilitated
over time. If I had my way every grease fitting in the while still in the machine. In addition to oil strainers and
plant would be protected by a plastic cap that prevents filters a lubricating system can contain water separators,
anything getting on that fitting between lubrications. magnetic separators, heaters and coolers to maintain the
I would also still require the fitting be cleaned before oil at its optimum operating temperature, and settling
attaching the grease gun. What if someone steps on the tanks to allow removal of solids and contaminants. The
plastic cap or hits it with something and you find it off? expensive oil is maintained by these systems to reduce
If I had my way the grease fitting would be replaced the cost of regular replacements but it requires attention
before installing a new cap. to maintenance of the oil systems.
Eliminating contamination of the bearing with If there isn’t an oil maintenance system you may
contaminated grease in the tip of the grease gun is also also have the option of an oil maintenance service, a
important. Always carry an additional lint free rag or company that will pick up and refine your used oil and
small bucket to collect a small amount of grease from the give you credit toward the purchase of new oil. Regular
gun before attaching it to the fitting. A quick shot into testing of the oil in those systems is essential to ensur-
the rag or bucket will eliminate any dust or other debris ing proper system operation and maintenance of the
that was picked up by the grease in the tip of the grease lubricating quality. Normally the testing of oil (tribol-
gun. ogy) is performed by outside laboratories that have
Sound like a lot more work? Perhaps you feel you all the required equipment. The oil is tested for water,
aren’t ready to go to all that trouble. The truth is that acidity, lubricating properties and microscopically. The
grease lubrication requirements are so infrequent that examination by a skilled technician with a microscope
people I’ve convinced to establish a good grease lubrica- can identify all the particles in the oil to reveal impend-
tion program find they’re doing half the work because ing bearing failure or problems with gears or other parts
they were lubricating their equipment too frequently. If of a machine.
you have a policy of greasing everything once a month, Maintenance of oil lubricated equipment requires
or more frequently, that’s probably the case. more attention than grease lubricated ones because the
Oil, like grease, varies in its application and you oil is exposed to the air in the plant. Grease systems are
must be certain you are using the proper oil for the basically sealed so air doesn’t contaminate them, that’s
equipment. A simple mistake involving oil can destroy a why some grease lubricated bearings can go 40,000
piece of equipment because one oil mixed with another hours, which is close to five years, without re-greasing.
can produce an incompatible mixture that loses all its When equipment starts and stops it breathes because the
lubricating properties. When that happens the mixture oil and air heat up then cool off to change volume so air
tends to split into a light fraction that is too thin to sup- has to bleed out then is drawn in. The grease changes
port the load and a sludge that settles to the bottom of volume but it’s normally such a small change that those
the sump or plugs up the pump and filters. seals expand and contract with it to prevent leakage of
Every piece of oil lubricated equipment should be contaminants in or grease out.
marked to clearly indicate which oil is to be used in it. Systems with oil temperature control will also
Refrigeration oils are addressed in Chapter 5. With all breath with changes in load because the temperature of
the changes in lubricants I wish someone would come some of the oil increases and decreases depending on the
up with some standard color coding (like those for re- load. Therefore equipment that is subjected to frequent
frigerants) to make it a little more difficult to use the stops and starts or varying loads requires more frequent
wrong lubricant. checks of the oil than those that operate continuously.
Preventing contamination of the oil in your equip- That’s why you will frequently see an accumulation of
ment by adding contaminated oil is very easy. Oil in- oil around an oil sump vent, it’s condensed vapors that
teracts with its environment more readily than grease were pushed out of the vent filter as the system breathes.
so you should always take every possible measure to If you, or your boss, object to the accumulation