Introduction to fluid power systems
Fluid power system: components, advantages and applications. Transmission of power at static and dynamic states. Pascal’s law and its applications. Fluids for hydraulic system: types, properties, and selection. Additives, effect of temperature and pressure on hydraulic fluid. Seals, sealing materials, compatibility of seal with fluids. Types of pipes, hoses, and quick acting couplings. Pressure drop in hoses/pipes. Fluid conditioning through filters, strainers; sources of contamination and contamination control; heat exchangers.
Pumps and actuators
Pumps:Classification of pumps, Pumping theory of positive displacement pumps, construction and working of Gear pumps, Vane pumps, Piston pumps, fixed and variable displacement pumps, Pump performance characteristics, pump selection factors, problems on pumps. Accumulators: Types, selection/ design procedure, applications of accumulators. Types of Intensifiers, Pressure switches /sensor, Temperature switches/sensor, Level sensor.
Actuators:Classification cylinder and hydraulic motors, Hydraulic cylinders, single and double acting cylinder, mounting arrangements, cushioning, special types of cylinders, problems on cylinders. Construction and working of rotary actuators such as gear, vane, piston motors, and Hydraulic Motor. Theoretical torque, power,flowrate, and hydraulic motor performance; numerical problems. Symbolic representation of hydraulic actuators (cylinders and motors).
Components and hydraulic circuit design
Components:Classification of control valves, Directional Control Valves-symbolic representation, constructional features of poppet, sliding spool, rotary type valves solenoid and pilot operated DCV, shuttle valve, and check valves. Pressure control valves - types, direct operated types and pilot operated types. Flow Control Valves -compensated and non-compensated FCV, needle valve, temperature compensated, pressure compensated, pressure and temperature compensated FCV, symbolic representation.
Hydraulic Circuit Design:Control of single and Double -acting hydraulic cylinder, regenerative circuit, pump unloading circuit, double pump hydraulic system, counter balance valve application,hydrauliccylinder sequencing circuits, cylinder synchronizing circuit using different methods, hydraulic circuit for force multiplication;speedcontrol of hydraulic cylinder- metering in, metering out and bleed off circuits.Pilot pressure operated circuits.Hydraulic circuit examples withaccumulator.
Pneumatic power systems
Introduction to Pneumatic systems:
Pneumatic power system, advantages, limitations, applications, Choice of working medium. Characteristics of compressed air and air compressors. Structure of pneumatic control System, fluid conditioners-dryers and FRL unit.
Pneumatic Actuators: Linear cylinder –types of cylinders, working, end position cushioning, seals, mounting arrangements, and applications. Rotary cylinders- types, construction and application, symbols.
Pneumatic Control Valves: DCV such as poppet, spool, suspended seat type slide valve, pressure control valves, flow control valves, types and construction, use of memory valve, Quick exhaust valve, time delay valve, shuttle valve, twin pressure valve, symbols.
Pneumatic control circuits
Simple Pneumatic Control:
Direct and indirect actuation pneumatic cylinders, speed control of cylinders - supply air throttling and exhaust air throttling.
Signal Processing Elements:
Use of Logic gates - OR and AND gates in pneumatic applications. Practical examples involving the use of logic gates.
Multi- Cylinder Application:
Coordinated and sequential motion control, motion and control diagrams. Signal elimination methods, Cascading methodprinciple, Practical application examples (up to two cylinders) using cascading method (using reversing valves).
Electro- Pneumatic Control:
Principles - signal input and output, pilot assisted solenoid control of directional control valves, use of relay and contactors. Control circuitry for simple signal cylinder application.
COURSE OUTCOMES:
After studying this course, students will be able to:
CO1 Identify and analyse the functional requirements of a fluid power transmission system for a given application.
CO2 Visualize how a hydraulic/pneumatic circuit will work to accomplish the function.
CO3 Design an appropriate hydraulic or pneumatic circuit or combination circuit like electrohydraulics, electro-pneumatics for a given application.
CO4 Select and size the different components of the circuit.
CO5 Develop a comprehensive circuit diagramby integrating the components selected for the given application.
TEXT BOOKS:
1. Anthony Esposito, “Fluid Power with applications”, Pearson edition,2000 .
2. Majumdar S.R., “Oil Hydraulics”,TalaMcGRawHllL, 2002 .
3. Majumdar S.R., “Pneumatic systems - Principles and Maintenance”,Tata McGraw-Hill, New Delhi, 2005
REFERENCE BOOKS:
1. John Pippenger, Tyler Hicks, “Industrial Hydraulics”, McGraw Hill International Edition, 1980.
2. Andrew Par, Hydraulics and pneumatics, Jaico Publishing House, 2005.
3. FESTO, Fundamentals of Pneumatics, Vol I,IIandIII.
4. Herbert E. Merritt, “Hydraulic Control Systems”, John Wiley and Sons, Inc.
5. Thomson, Introduction to Fluid power, PrentcieHaIl, 2004
6. John Watton, “Fundamentals of fluid power control”, Cambridge University press, 2012.
Scheme of Examination:
Learning Assignment:
The faculty will allocate one or more of the following experiments from group A and B to group of students( containing not more than fourstudents in a group):
Group A: Experiments on hydraulic trainer:
a. Speed control circuit using metering in and metering out technique
b. Regenerative and sequencing circuits.
c. Extend-Retract and Stop system of a linear actuator
d.Rapid Traverse and Feed circuit.
Group B: Experimentson pneumatic trainer:
a. Automatic reciprocating circuit
b. Speed control circuit
c. Pneumatic circuit involving shuttle valve/ quick exhaust valve
d. Electro pneumatic valves and circuit
Students should build up the above circuits on computer using software and simulate the flow of fluid during the operation. Afterwards, they themselves can physically connect the circuit on the hydraulic/pneumatic trainer and run the circuit. Record of experiments shall be submitted in the form of journal. Due credit must be given for this assignment (5 Marks).
List of Open Source Software/learning website:
1. Simulink
2. SimHydraulics