1. In this presentation you will:
identify how to control the speed and position of hydraulic cylinders

2. In this presentation you will explore some of the ways in which cylinders are controlled.
Needle
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3. Cylinder Control - Two Positions
Mechanical control
Tank
Pump
Spool valve
Hydraulic cylinder
Piston
A basic hydraulic circuit is shown.
The cylinder is controlled by a two position spool valve that has a lever actuator.
The pump provides a constant supply of pressurised fluid.
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.
Because the valve has only two positions, the piston has only two positions - in or out.
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4. Question 1
A two position spool valve can stop a piston in any position. Is this true or false?
Answer True or False.

5. Cylinder Control - Stop in Any Position
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 can be used to perform this function.
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6. Stop in Any Position - Hydraulic Circuit
Mechanical control
Tank
Pump
Spool valve
Hydraulic cylinder
Piston
A basic hydraulic circuit is shown.
The cylinder is controlled by a three position spool valve that has a lever actuator.
The pump supplies a constant supply of pressurised fluid.
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.
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.
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7. Question 2
How many positions must a spool valve have, to stop a piston in any position?
A) 0
B) 1
C) 2
D) 3

8. 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.
Adjustable Needle
On/Off valve starts or stops fluid flow.
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.
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9. Question 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.

10. Summary You should now be aware of how to control cylinder: Position
Speed
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