Introduction to Hydraulics
In this presentation you will:
 identify the fundamental parts of a hydraulic system and safety
issues relating to hydraulics
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Introduction to Hydraulics
In this presentation you will see what
hydraulic systems are.
You will explore some of the safety
issues associated with hydraulic
systems and the fluids used in
them.
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Introduction to Hydraulics
Components of Hydraulic Systems
All industrial hydraulic systems will have:
 A fluid, usually oil.
 A tank, or reservoir, to hold a
supply of the fluid.
 A pump to cause the fluid to flow.
 An electric motor, or engine,
to drive the pump.
 Hoses or tubing to carry the fluid.
 Valves to control fluid flow,
direction and pressure.
 One or more actuators, usually cylinders or hydraulic motors,
to do the work where mechanical movement occurs.
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Introduction to Hydraulics
Question 1
Two engineers are discussing the components required to make an
industrial hydraulic system. Engineer A says a reservoir is needed to
hold a supply of fluid. Engineer B says a motor driven pump is needed
to cause the fluid to flow. Who is correct?
A) Only engineer A
B) Only engineer B
C) Both engineer A and B
D) Neither engineer A or B
Introduction to Hydraulics
Compression of Fluids
Two cylinders are shown. One
cylinder contains a gas and the
other contains a liquid.
If a downward force is applied to
the piston in the gas cylinder, the
piston will move down and
compress the gas.
If a downward force is applied to
the piston in the liquid cylinder, the
piston will not move.
Hydraulic cylinders use liquid,
which is incompressible.
Closed cylinder
containing air
(gas)
Closed cylinder
containing
hydraulic fluid
(liquid)
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Introduction to Hydraulics
Hydraulic Fluids
The primary purpose of hydraulic fluid is to transmit force from one place to
another.
However, hydraulic fluids are also
required to:
 Lubricate contact surfaces within the
system.
 Provide sealing of components, where
tight clearances are involved.
 Remove heat generated within the system.
 Protect system components against rust, oxidation and corrosion.
 Prevent foaming when subjected to turbulence.
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Introduction to Hydraulics
When selecting a hydraulic fluid for an application, consideration must be
given to the pressure, temperature and materials of the system.
Improper selection can lead to:

Inadequate system
performance.

Premature failure of
components.

The potential for fire.

Environmental pollution in the
event of loss of containment.
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Introduction to Hydraulics
The main types of hydraulic fluid are:
Petroleum based fluids:
Most common type of fluid.
Synthetic fire resistant fluids:
Used where fire hazards or environmental
pollution are a concern.
Water based fire resistant fluids:
Used where fire hazards or environmental
pollution are a concern.
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Introduction to Hydraulics
Hydraulic Fluid Safety
Generally, hydraulic fluid:
 Can cause skin and eye irritation.
 Can cause medical problems. If
ingested; seek medical attention
immediately.
 May cause medical problems,
if repeatedly inhaled.
 May be corrosive.
 Must be disposed of according to
Environmental regulations.
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Introduction to Hydraulics
Question 2
Which of the following is NOT a function of hydraulic fluid?
A) To cool system components
B) To lubricate system components
C) To protect against corrosion
D) To expand and seal components
Introduction to Hydraulics
Hydraulic Systems Safety
Here are some general safety procedures for working on hydraulic systems:
 Always wear eye protection and appropriate clothing.
 Never service the system while the pump is running (unless bleeding
the system).
 Do not remove cylinders until the working units are resting on the floor or
ground, on safety stands or on blocks.
 Before disconnecting oil lines, relieve all hydraulic pressure and
discharge the accumulator.
 Ensure that all line connections are tight and the lines are not damaged.
Escaping oil under pressure is a fire hazard and can penetrate the skin
causing serious injury.
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Introduction to Hydraulics
Question 3
Which of the following tasks can be worked on, while the hydraulic
pump is running?
A) Removing cylinders
B) Bleeding the system
C) Disconnecting lines
D) Servicing the system
Introduction to Hydraulics
Summary
You should now be aware of:
 The fundamental parts of
hydraulic systems
 Hydraulic fluid
 How to work safely with
hydraulic systems
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