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Hydraulic system consists of following componentsPower sources units:1) Tank or reservoir Pressurized tanks, Vented tanks, Oil
cooler2) Filters Suction filter, return line, Pressure
line filters3) Hydraulic Piping Hose , Pipe, Fittings, Pressure
gauge, Temperature gauge
4) Positive displacement Pumps Internal/external gear Pump
Screw,lobe,Vane ,Plunger pump, Piston pump
Power Control Units:5) Flow control valves Regulating type, Control type6) Check valves NRV,Pilot operated check valves3) Pressure control valves Pressure Relief valves , Unloading valves,
Sequence valves, Pressure-reducing valves , Counterbalance valves, Safety Valve4)Direction control valves Poppet, Spool , Rotary valves,
One,two,three way,
DRIVE units: 7) Actuators Linear, Rotary, 1,2CYLINDERS,
Telescopic cylinder, Hydraulic motors
Auxiallry Power source units:1)Accumulators Weight loaded, Spring loaded, Gas
charged
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Hydraulic Systems
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Basic Components in Hydraulic Systems
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1.RESERVOIR
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Hydraulic Tank Function
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How Reservoirs Work
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Hydraulic Tank Function
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2. Filters
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Hydraulic oil contamination
Particles In Hydraulic Oil
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Contaminant Types And Causes
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Abrasion Classes
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A hydraulic hose is a high-pressure, synthetic rubber, thermoplastic or Teflon reinforced hose that carries fluid to transmit force within hydraulic machinery
3.Hydraulic hose
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4. Hydraulic steel PIPES
It also carries fluid to transmit force within hydraulic machinery
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PUMPS• Positive displacement
pump (Gear Pump): a specific amount of fluid passes through the pump for each rotation
• Centrifugal pump (Vane Pump): no specific amount of fluid flow per rotation; flow depends on speed of blades
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Positive displacement vs Centrifugal pump Curve
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PISTON PUM PS
PLUNGER PUM PS
DIAPHRAGM PUM PS
REC IPRO C A T ING PUM PS
G EAR PUM PS
LOBE PUM PS
SCREW PUM PS
CAM PUM PS
VANE PUM PS
RO T A RY PUM PS
PO S IT IV E D IS PL A C E M ENT PUM PS C ENT RIF UG A L PUM PS
PUM PS
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• Displacement relates to how the output of the pump reacts to system loads– Non-positive-displacement pumps produce flow variations due to internal slippage.
– Positive-displacement pumps produce a constant output per cycle
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• A non-positive-displacement pump has large internal clearances– Allows fluid slippage in the pump– Results in varying flow output as system load varies
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Key Feature of a V-Displacement Pump
• Fixed Displacement Pump –A fixed volume of fluids
will be provided in each revolution
Variable Displacement Pump _The volume of
supplying fluids may be change based on demands
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Vane Pumps
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Internal Gear Pump
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Internal Gear Pump
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Internal Gear Pump
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• Operation of a lobe pump
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• A typical screw pump
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Operation Principle of Piston Pumps
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A rotor-gear pump is a variation of the internal-gear pump.
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Rotor-gear Pumps
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Hydraulic oil cooler
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If the pump is the heart of a hydraulic system then the valve is the brain.Valves are used to perform a large variety of governing and controlling functions.
Valves
Function:• pressure control valves• flow control valves• check valves (non-return
valves)• directional control valves
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Form:
a) Sphericalb) c) d) e) Conicalf) Plateg) Spool valve
Poppet valve
Aspects of classification
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Flow valvesBasics:The velocity of hydraulic cylinders can be influenced by the flow rate.This can be done by an adjustable pump or by a flow rate control valve.The flow rate is changed by changing an orifice surface area or by changing the pressure difference on a resistance or dividing the flow rate.Advantages of flow valves are: simplicity safe operation good dynamic behaviour precision
Disadvantage: the relatively high energy losses
Types: Restrictor valves (throttle valves) Flow control valves Flow dividing valves
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Flow Control Valves
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Control Valves Regulating Valves
Restrictor Orifice One Way Two Way
Flow Control Valve
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Restrictors & Orifices valves
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(a) In flow control
(b) out flow control
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Check Valves
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Pilot-operated check valves:
Pilot pressure to open check valve
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SHUTTLE VALVE
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1. Relief valves
2. Unloading valves
3. Sequence valves
4. Pressure-reducing valves
5. Counterbalance valves
6. Safety Valve
Types of Pressure Control Valves
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Pressure relief valve
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1- Direct Acting Relief Valve(PRV)
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Fs > Fp
Fs < Fp
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Pressure relief valve
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Normal flow, no over load
Pressure relief valve
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2- Pilot-Operated Relief Valve
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2- Pilot-Operated Relief Valve
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2- Pilot-Operated Relief Valve
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Unloading valves
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Sequence valves
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Sequence valves
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Pressurereducing valves
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Pressure-reducing valves
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Counterbalance valves
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Counterbalance valves
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Directional Control Devices• Typical spool valve
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Solenoid Operated Spool Valves
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ACTUATORS
Hydraulic actuators convert the fluid power from the pump into mechanical work.
A hydraulic cylinder is a linear actuator.
A hydraulic motor is a rotary actuator.
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Telescopic Cylinder
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HYDRAULIC MOTORS
The function of hydraulic motors is the opposite of hydraulic pumps:
Pump It draws in oil and displaces it, converting
mechanical force into fluid force. MotorOil under pressure is forced in and spilled out,
converting fluid force into mechanical force.
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GEAR MOTORS
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