1. HYDRAULIC OILS

2. What are hydraulic oils???
 They are the medium by which power is
transferred in hydraulic machinery
.
 A liquid such as oil or water that is used
to generate power in a hydraulic system.
 Examples of equipment that might use
hydraulic oils include and backhoes,
brakes, power steering systems,

3. transmissions, aircraft flight control
systems, elevators and industrial
machinery.
 Hydraulic systems like the ones
mentioned above will work most
efficiently if the hydraulic fluid used has
low compressibility.

4. Characteristics and properties
 Low temperature sensitivity of
viscosity;
 Thermal and chemical stability;
 Low compressibility;
 Good lubrication (anti-wear and anti-
stick properties, low coefficient of
friction);

5.  Hydrolytic stability (ability to retain
properties in the high humidity
environment);
 Low pour point (the lowest
temperature, at which the oil may
flow);
 Water emulsifying ability;
 Filterability;
 Rust and oxidation protection
properties;

6.  Low flash point(the lowest temperature,
at which the oil vapors are ignitable);
 Resistance to cavitations;
 Low foaming;
 Compatibility with sealant materials.

7. FUNCTIONS
 The primary function of a hydraulic fluid
is to convey power.
 Protection of the hydraulic machine
components.
 Heat transfer
 Sealing medium
 Lubricant

8. COMPOSITION
Base Stock
 The original hydraulic fluid, dating back
to the time of ancient Egypt, was water.
Beginning in the 1920s, mineral oil
began to be used more than water as a
base stock due to its inherent lubrication
properties and ability to be used at
temperatures above the bp of water.
Today most hydraulic fluids are based
on mineral oil base stocks.

9.  Natural oils such as rapeseed used as
base stocks for fluids where
biodegradability and renewable sources
are considered important.
 Other base stocks are used for specialty
applications, such as for fire resistance
and extreme temperature applications.
Some examples include: glycol, esters,
organophosphate ester, polyalphaolefin,
propylene glycol, and silicone oils.

10. Biodegradable hydraulic
fluids
 Environmentally sensitive applications may
benefit from using biodegradable hydraulic
fluids based upon rapeseed, vegetable oil
when there is the risk of an oil spill from a
ruptured oil line. Typically these oils are
available as ISO 32, ISO 46, and ISO 68
specification oils. Guide for Assessing
Biodegradability of Hydraulic Fluids
Standard Classification of Hydraulic Fluids
for Environmental Impact are relevant.

11. Contamination
 Special, stringent care is required when
handling aircraft hydraulic fluid as it is
critical to flight safety that it stay free
from contamination. It is also necessary
to strictly adhere to authorized
references when servicing or repairing
any aircraft system. Samples from
aircraft hydraulic systems are taken
during heavy aircraft maintenance
checks to check contamination.

12.  Because industrial hydraulic systems
operate at hundreds to thousands of PSI
and temperatures reaching hundreds of
degrees Celsius, severe injuries and
death can result from component
failures and care must always be taken
when performing maintenance on
hydraulic systems.
 Fire resistance is a property available
with specialized fluids.
Safety

13. ADVANTAGES
 Higher efficiency
 Better performance
 Environment friendly
 Can be used at very extreme
temperatures
 Also works as lubricant while
transmitting power

14.  Higher heat transfer capability than
water
 Also acts as a sealing medium
 No wear as the working parts are not in
contact.

15. DISADVANTAGES
 A constant high pressure is required to
be maintained.
 Leakage may occur.
 Aeration may occur through the pump
causing noisy operation, power lag,
knocking etc.

16. Thank you