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Controlling Cylinders
In this presentation you will:
identify how to control the speed and position of hydraulic
cylinders
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Controlling Cylinders
Next >
In this presentation you will explore
some of the ways in which cylinders
are controlled.
Needle
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Controlling Cylinders
CylinderControl - Two Positions
The pump provides a constant
supply of pressurised fluid.
Next >
A basic hydraulic circuit is
shown.
When the lever is pushed forward, pressurised fluid is applied
to the left side
of the cylinder - the piston extends.
When the lever is pulled back, pressurised fluid is applied to
the right side of
the cylinder - the piston retracts to its home position.
The cylinder is controlled by
a two position spool valvethat has a lever actuator.
Because the valve has only two positions, the piston has only
two
positions - in or out.
Mechanical
control
Tank
Pump
Spool
valve
Hydraulic cylinderPiston
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Controlling Cylinders
1
A two position spool valve can stop a piston in any position. Is
this
true or false?
AnswerTrue or False.
Question
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Controlling Cylinders
CylinderControl - Stop in Any Position
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A hydraulic system may have a
requirement for a cylinder to stop in
any position within its working range.
A typical application is a hydraulic lift.
The operator must be able to stop
the lift at any height, between its
operating limits, with safe control.
A three position spool valve canbe used to perform this
function.
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Controlling Cylinders
Stop in Any Position - Hydraulic Circuit
The pump supplies a constant
supply of pressurised fluid.
Next >
A basic hydraulic circuit is
shown.
When the lever is pushed forward, pressurised fluid is applied
to the left side
of the cylinder. The piston extends.
When the lever is pulled back, pressurised fluid is applied to
the right side of
the cylinder. The piston retracts to its home position.
The cylinder is controlled by
a three position spool valvethat has a lever actuator.
When the lever is set to off, fluid flow to and from the
cylinder is
halted, piston movement stops and the piston is locked in
position.
Mechanical
controlTank
Pump
Spool
valve
Hydraulic cylinder
Piston
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Controlling Cylinders
2
How many positions must a spool valve have, to stop a piston in
any
position?
Question
A) 0
B) 1
C) 2
D) 3
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Controlling Cylinders
On/Off valve starts or stops fluid flow.
Flow Control Valves to Adjust Speed
Valves control the flow of the fluid in
a hydraulic system. Controlling the
rate of fluid flow in a cylinder will
control the speed of the piston.
Depending on the type of valve used, the
fluid can be stopped and started or the
speed increased or decreased. The
larger the gap the larger the fluid flow.
Next >
Adjustable Needle
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Controlling Cylinders
3
A flow control valve such as a needle valve could be used to
control
the speed of the fluid in a hydraulic system. Is this statement
true?
Answer Yes or No.
Question
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Controlling Cylinders
Summary
You should now be aware of how to control cylinder:
End >
Speed
Position
