Lubezine Magazine Vol. 9 April - June 2014 | Page 21

Global additive use to hit
4.5 Million tons by 2017

See story

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FACTBOX: GEOTHERMAL ENERGY

Africa’s estimated geothermal potential along the Great Rift Valley.
SOURCE: Geothermal Power (T) Limited

• Cleanliness: it is necessary to find source of
particulates, e.g. make up oils, dust or ash
entering system, wear, etc.
The most common viscosities used in
turbines are the ISO viscosity grades 32, 46,
and 68.

Hydraulic Oils
The primary purpose of hydraulic fluid is to
transmit power. To accomplish this effectively, the fluid must be incompressible and
flow readily through the system. The fluid
must also have sufficient viscosity to seal and
lubricate the components of the hydraulic
system. Hydraulic oil has many of the same
requirements as lubricating oil used in the
unit bearings, and, in many cases, the same
oil can be used.
February-April 2014 | LUBEZINE MAGAZINE

Greases
Grease for the slow moving, highly loaded,
bronze bushings such as those found on
wicket gates, radial gates, and butterfly valves
should be adhesive, water resistant, able to
withstand high bearing pressures, and of
a consistency that can be pumped at the
lowest temperature encountered. Usually,
grease with extreme pressure or an anti-wear
capability is specified. Because the grease is
lubricating a bronze bearing, it should not be
corrosive to copper.

Gear Oil
Gears vary greatly in design and in their
requirements for lubrication. Factors such as
speed, load, and temperature, must be considered when choosing gear oil. Enclosed gears

usually use a mineral oil with rust, oxidation,
and foam inhibitors and, where loads are
severe, extreme pressure additives.
Worm gears don’t generally require
Extreme pressure additives but lubrication
can be improved by lubricity additives.
For open gears, a highly adhesive lubricant
is required. It must be able to resist being
thrown off by centrifugal force or being
scraped off by the action of the gear teeth.
Most open gear lubricants are heavy oils,
many times asphalt based, or soft greases.
Depending on the service conditions, oxidation inhibitors or extreme pressure additives may be added. Because these lubricants
are very adhesive, they also attract dust and
dirt. These contaminants can act as abrasives
if the gears are not periodically cleaned.

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