2. Fluid Power System
• The pressure fluids to move one place to another.
– Hydraulic System (Hydour-Water in Greek word )
(High accuracy)
Examples: Space, defense, machine tool
applications, agriculture and automobiles.
– Pneumatic System (Pneuma- Air in Greek word)
(Less accuracy)
Examples: pneumatic hammers, drills, hoists, cranes.
3. 1. Fluid power system and
2. Hydraulic System
3. Oil Hydraulic System
4. SERVICE PRPERTIES OF HYDRAULIC FLUIDS
1)Viscosity
-To affect the running fluid
Depends on,
-Temperature
-Thickness
- Pressure
Density = Viscosity Temperature +++
Viscosity ---
Pressure +++
Viscosity ---
So we chose fluid is to reduced the above failures
5. 2) Viscosity Index
-Temperature Changes to
Change the Viscosity
-Integer (0 to 100)
To choose the High viscosity
index fluid.
6. 3) Oxidation stability
Chemical
Oil + AIR(OXYGEN) Oxidation
Reaction
Oxidation Inhibitors Or Additives …
Ex: Silicon Polymers, Nitrogen Components etc.
4) De-emulsibility
-Reduce the Forming
in hydraulic fluid
-Separate the forming and
hydraulic fluid
7. 5) Lubricity
-Lubricate the all engine parts during function of
system.
-avoid friction loss by using high lubricity having
fluid will choose,
6) Rust Prevention
-Rust is an iron oxide, usually red oxide formed by
the redox reaction of iron and oxygen in the presence
of water or air moisture
Ex: Sprayer Paints etc.
8. 7) Toxicity
-Poison character or Silly Character.
- This behaviour defiantly affect the human being..
8) Cloud point
-Cloud point refers to the temperature below which wax
in oil .
9) Flash and Fire Point
At the flash point, the vapor may cease to burn when
the ignition source is removed. The flash point is not to be confused with the
auto ignition temperature (which does not require an ignition source) or with
the fire point (the temperature at which the vapor continues to burn after
being ignited).
9. HYDRAULIC ACCUMULATOR
A hydraulic accumulator is a pressure storage reservoir in
which a non-compressible hydraulic fluid is held under pressure by an
external source. The external source can be a spring, a raised weight, or
a compressed gas.
10. Usage of Accumulator
1. Leakage compensation
2. Shock absorber
3. Secondary power sources
4. Emergency power sources
5. Thermal expansion compensator
6. Temporary storage receiver etc.
Leakage compensation
11. SHOCK ABSORBER
A shock absorber (in reality, a shock "damper") is a mechanical
or hydraulic device designed to absorb and damp shock impulses.
SECONDARY POWER SOURCE
Supply to extra fluid to hydraulic system.
EMERGENCY SOURCE
During Emergency time to supply hydraulic
fluid from accumulator. If any fault in pump.
20. PRESSURE INTENSIFIER
Pascal's law - pressure applied anywhere to a body of fluid
causes a force to be transmitted equally in all directions; the force acts at
right angles to any surface in contact with the fluid; "the hydraulic press is
an application of Pascal's law" Pascal's law of fluid pressures.
PASCAL'S LAW
21. A hydraulic intensifier is a device which is used to increase the
intensity of pressure of any hydraulic fluid or water, with the help of the
hydraulic energy available from a huge quantity of water or hydraulic fluid at
a low pressure.
These devices are very important in the case of hydraulic machines,
mainly hydraulic presses, which require water or hydraulic fluid at very high
pressure which cannot be obtained from the main supply directly.
There are three main parts in the hydraulic intensifiers to be noted. They are
1. Fixed ram,
2. Hollow inverted sliding cylinder,
3. Fixed inverted cylinder.
Application :
Moulding Machine, Riveting machine, Spot Welding Machine and
Hydraulic Presses.
22. Fluid Power Pumps
Pump:
-Important system in hydraulic system
-Motor helps to convert electrical energy into mechanical energy
-Pump helps to convert mechanical energy into fluid flow energy.
Classification of pumps:
1. Gear pump External Gear Pump
2. Vane pump
3. Radial pump Internal Gear Pump
External Gear Pump:
1. Mostly Used in hydraulic system.
2. Equal two meshing gear fixed inside of casing.
Merits:
1)Simple in construction
2) Comfortable for all area
3)High pressure (Apporx. 150bar)
4) Low cost.
23. Internal Gear Pump:
Here Spur and internal gear meshing with help of crescent seal and
casing
Merits:
1)Simple in construction 2) Comfortable for all area 3) Low cost.
Demerits:
1) Less pressure (70bar) 2) Less Capacity
Vane Pump:
Here Casing, Shaft, rotor and eccentricity.
Merits:
Oil Leakage less and High Volumetric efficiency 95% and medium cost.
Demerits:
1) Less pressure 2) Less Capacity
24. Radial Gear Pump
1. Fixed pintle, cylinder block and reaction ring.
Merits:
1) Smooth Operation 2) Pump Output high
3) high volumetric efficiency (98%) 4) High Pressure (Above 500bar)
Demerits :
1) Difficult Construction and High cost.
