Title
: Hydraulic System.
Objective
:
1. To assemble, test and tr ouble shoots (if necessary) and a nd describes the operation of hydraulic cylinder in tensi on, retraction and st opped positions. 2. To familiarizes the student with the a pplications of a 4/3-way valve 3. 3. To show how to use a piloted non-return valve
Introduction
:
Hydraulics is the science of transmitting f orce and motion thr ough the medium of a confined liquid. Electr o-hydraulic system is the c ombination of electrical and hydraulic system. The range of a pplications f or electr o-hydraulic systems is diverse, and includes manufacturing systems, materials test machines, sus pension systems, mining machinery, fatigue testing, flight simulation, paper machines, shi ps and electr omagnetic marine engineering, injecti on moulding machines, r obotics, and steel and aluminium mill equi pment. Hydraulic pumps, mot ors, and cylinders can be c ombined int o hydraulic drive systems. One or more hydraulic pumps, coupled t o one or more hydraulic motors, constitute a hydraulic transmissi on.
In a hydraulic device, power is transmitted by pushing on a c onfined liquid. The transfer of energy takes place because a quantity of liquid is subject t o pressure. By a pplying a downward f orce on the small piston, the jack can be made t o lift a heavy mass on the large piston. The liquid fills the entire v olume between the tw o pistons, and because it is
incompressible, s ome liquid must move int o the large piston chamber when the small piston is pushed downward. Hydraulic systems operate according t o Pascals law. The law of Blaise Pascal says: 'The pressure, in a static hydraulic fluid in a cl osed system is everywhere the same'. However, when the vel ocity of the fl ow is c onstant one may a pply Pascals Law as well.
Hydraulic systems are als o common in aircraft, where their high power-to-weight ratio and precise contr ol makes them an ideal ch oice f or actuation of flight surfaces. A electr o
hydraulic motor is a mechanical actuat or that converts hydraulic pressure and fl ow into torque and angular dis placement (r otation). The hydraulic m otor is the r otary counter part of the hydraulic cylinder c onceptually, a hydraulic motor should be interchangeable with a hydraulic pump because it perf orms the opposite function - much as the c onceptual DC electric motor is interchangeable with a DC electrical generat or. However, most hydraulic pumps cannot be used as hydraulic m otors because they cann ot be back driven. Als o, a
hydraulic motor is usually designed f or the working pressure at b oth sides of the motor.
Material and
equipme nt:
Electr o hydraulic system
FIRUGE : Electr o hydraulic system
Procedures
:
The followi
procedures are i cluded: 1. The hydraulic system is turned ON 2. The work ing pr inciple of the hydraulic system is studied and understood 3. The hydraulic circuit of the system is drawn 4. Af ter the exper imental this electro-hydraulic system with new design has been constructing and performance enhancement of the system has been recorded. 5.
One application of the hydraulic system is proposed
Hydraulic Circui :
Motor
4/3 way solenoid operated with spr i ng return control valve
Pressure
Valve
R elief
Tank
Potenti al
Application:
The hydraulic system can be used as:
Heavy duty drilling machine
Screw fasteners.
Load lifters.
Machine squeezer.
Gigantic door opener / lifter such air plane hangar door.
Opening / closing sliding door.
Manufacturing line a pplication such as Extrusi on Machine and Stamping Machine.
The range of a pplications f or electr o-hydraulic systems is alm ost same with hydraulic system,
but the main pur poses electr o hydraulic system c ompare to conventional system is t o give operator easily t o operate. Since electr o hydraulic use s olenoids t o generate the
electr omagnetic f or valve activation, operator not need manually ( pull the lever or push the butt on) activate the valve. This can save time, energy and can give this electr o hydraulic system more efficient and practical to use.
The typical application of this electr o hydraulic system are include in manufacturing systems,
materials test machines, active sus pension systems, mining machinery, fatigue testing, flight simulation, paper machines, shi ps and electr omagnetic marine engineering, injecti on molding machines, r obotics, and steel & aluminum mill equi pment. The Hydraulic systems are als o common in aircrafts, where their high power-t o-weight ratio and precise contr ol makes them an ideal choice f or use in flight traject ory c ontr ol.
Discussion:
The hydraulic system lab is g ood t o study. Student can know ab out the system, a pplication,
circuit diagram and the advantage of the hydraulic system. As f or the discussi on there are some matters that have t o be c onsidering that will hel p to impr ove the lab. Firstly, the hydraulic system have s ome working fluid leaking, this can be av oided by using pressure sealant. Second, the system is a l ot of mess and need f or maintenance that c ould help avoiding the a pparatus t o perf orm better and not br oken.
5.0
RECOMMENDATIONS (improveme nt):
Since the difference between c onventional system and electr o hydraulic system are n ot much only on activation part, so the weaknesses of this system als o alm ost same with c onventi onal
system. Theref ore the ways t o impr ove this system are quite same with the hydraulic system.
Weaknesses of hydraulic y
Working fluid leak fr om the
Impr ovement y
Use high pressure sealant
y
Use heat sink t o dissipated heat
system (messy) y
Hydraulic system over heating (can effect sealant bonding)
y
Need
period maintenance
y
Noisy
y
Need
system
DC power output to connect
with solenoid (not portable)
fr om the working fluid y
Use hydraulic system wisely
y
Use low noise motor
y
Use internal DC power output such as battery.
Conclusion:
As a conclusion the electr o hydraulic system is n ot new. This lab c ould assist us m ore to understand the principal of electr o hydraulic system. The application of electr o hydraulic system might able t o give extra skill t o the student in hydraulic area that is useful f or future need. There are continuing impr ovement need t o be made t o maintain the effectiveness and the perf ormance of the system. As c onclusion, the lab beneficial t o student and the lab was success.
REFERENCES:
1. http://en.wikipedia.org/wiki/Hydraulic_m otor 2. http://en.wikipedia.org/wiki/Electr ohydraulic_manual_transmission 3. http://materialhandling.globalspec.com/LearnMore/Flow_ Transfer_C ontr ol/Valve_Actuators_P ositi oners/Hydraulic_Electr ohydraulic_Valve_Actuators
