Hydraulic System basic working principle.

1. Hydraulic Syatem Basic By Vipin Kumar

2. Context
1
2
3
4
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Hydraulic System Definition
Pascal Law
Hydraulic System Symbols
Basic of Hydraulic Pumps & Motors
Basic of Directional Valves
5 Hydraulic Pump
6
7
8
9
10
Hydraulic Motor
Major Valves Setup
Close Loop VS Open Loop
Basic Hazard
Q&A

3. Hydraulic: DEFINITION
Hydraulic: A hydraulic system is a drive technology where a pressurized fluid is used to
perform the work, e.g. an electric motor to an actuator, such as a hydraulic cylinder.
P = F / A
P = Pressure
F = Force
A = Area
Hydraulic systems are based on Pascal's law which states that any pressure applied to a fluid inside a closed system
will transmit that pressure equally everywhere and in all directions.

4. A B
Pascal Law
4
Any force applied to a confined fluid is transmitted uniformly in all directions throughout the
fluid regardless of the shape of the container.
P = F / A
P = Pressure
F = Force
A = Area
F1 = P1A1
P1 = F1/A1
P1 = 10N / 2m2
5N/m2
F2 = P2A2
P2 = F2/A2 = F1/A2
F2 = F1/A1 * A2
5N/m2 * 20m2 = 100N
W1 = W2
F1H1 = F2H2
W = Work
H =Height W1 = W2
F1H1 = F2H2
H2 = (10N*10mtr) / 100N
1mtr

5. Sample CKT

6. Basic Symbol Used
Normal working line
Pilot line
Drain line
Enclosure outline
Direction of flow
Flexible working line
Joining lines
Crossing lines
Line

7. Basic Symbol Used
eservoir
Connecting lines
above fluid level
Connecting lines
below fluid level
Sealed
Open

8. Basic Symbol Used
ther Elements
Basic filter/strainer
Filter-separator
Manual Automatic
Separator
Cooler
Liquid Gaseous
Heater
Temp. controlled
M
Electric Motor

9. Basic Symbol Used
asuring Equipment
Pressure
Temperature
Float switch
Flow meter, rate
Flow meter, totalizing
Pressure Switch

10. Fixed displacement
Variable displacement, non-
compensated, unidirectional
Variable displacement, non-
compensated, bidirectional
Pump
Variable displacement,
pressure-compensated,
unidirectional
Variable displacement,
pressure-compensated,
bidirectional
Basic Symbol Used

11. Motor
Fixed displacement,
unidirectional
Fixed displacement,
bidirectional
Variable displacement,
unidirectional
Variable displacement,
bidirectional
Basic Symbol Used

12. Valves
Basic Symbol Used
Orifice
Check valve
Directional valve
Relief Valve
Sequencing Valve
Pressure Reducing/Regulating Valve
Flow control with bypass, pressure
compensated
Flow control with bypass, pressure and
temperature compensated
Unloading
Valve
Counterbalance
Valve

13. ectional Valves
Basic Symbol Used
Normally closed,
two-way, two port
Normally closed, two-way,
two position, two port
Normally closed, four way,
three position, four port
Normally open, two-way,
two position, two port
 Tandem Center -
P line connected to T line
A B
T
P
 Float Center –
P line block, A&B to T line
A B
T
P
 Close Center –
P,T,A&B line block
A B
T
P
 Open Center –
P,T,A&B line connected
A B
T
P

14. Controls
Basic Symbol Used
Liquid pilot
Gas pilot
Servo
Pilot or solenoid
Pilot and solenoid
activated, spring return
Push Button
Lever
Pedal
Cam
Solenoid

15. Cylinders
Basic Symbol Used
Single acting Double acting
Single acting, spring
return
Double acting,
single cushion
Double acting,
Double cushion
Telescoping
Ram
Pressure intensifier
Double acting, double
adjustable cushion
Double acting,
double rod

16. Hydraulic Pump
Pump
› Compensating Pump
A pressure compensated pump is a pump that can reduce its output displacement (flow) when the
system pressure rises to a specified pressure setting.
• Variable Displacement Compensated Vane Pump
• Variable Displacement Compensated Piston Pump
› Non - Compensating Pump
A non-compensated pressure pump has no pressure controls built in.
For this reason, the hydraulic system must contain a relief valve to
limit the maximum system pressure..
• Fixed Displacement Non Compensated Gear Pump

17. Hydraulic Motor
Motors
A hydraulic motor is a mechanical actuator that converts hydraulic pressure and flow into torque and
angular displacement (rotation).
• Vane Motor
• Gear Motor
• Gerotor Motor
• Axial Plunger Motor
• Radial Piston Motor
Major Component
• Drive Port – A & B
• Drain Port
• Break Line

18. Basic Valves Setup
unter Balance

19. Basic Valves Setup
eter in/out
Meter IN CKT Meter OUT CKT

20. Hydraulic CKT
en VS Close Loop

21. Hydraulic CKT
losed Loop

22. Hazards Of Hydraulic System
Hazard
 Heat
• Hydraulic systems can become quite hot when working hard.
Precaution - Use caution and wear gloves and safety glasses around working hydraulic
systems.
 Flammability
• Hydraulic oil will burn when exposed to a flame. This is especially true if the fluid is a thin
film or if it sprays out as a jet from a leakage point.
Precaution - Use caution and wear gloves and safety glasses around working hydraulic
systems.
 High Pressure lose & Fitting Failures
• While rare, it is possible for a hose or fitting to fail under pressure.
Precaution – To avoid failures replace hose as soon as there are any sign of fatigue,
cracking, blistering or hose slipping from crimped fitting. Don’t work on pressurized line.

23. Thank
You
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