Military Production MinistryTraining Sector
HYDRAULIC AND PNEUMATIC SYSTEMDirectional Control Valves
January
2013
Eng. Ahmed Saeed Eladlyhttp//:ASEladly.webs.com
Hydraulic SystemDIRECTIONAL CONTROL VALVES
Actuators Section
Power Control
Slide2Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
Control Section
Power Supply Section
Hydraulic D.C.VDIRECTIONAL CONTROL VALVES
Slide3Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Hydraulic SystemDIRECTIONAL CONTROL VALVES
Slide4Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
Hydraulic SystemDIRECTIONAL CONTROL VALVES
Slide5Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
Hydraulic SystemDIRECTIONAL CONTROL VALVES
Slide6Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
No. of Positions
2/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
2
2=
No. of Ports
Slide7Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
No. of Positions
3/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
3
2=
No. of Ports
Slide8Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
3/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide9Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
3/2 D.C.V with slide principle( closed position)
3/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide10Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
3/2 D.C.V with slide principle( Opened position)
3/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide11Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
3/2 D.C.V with slide principle( closed position)
3/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide12Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
3/2 D.C.V with slide principle( opened position)
3/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide13Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
3/2 D.C.V with Poppet principle( closed position)
3/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide14Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
3/2 D.C.V with Poppet principle( Opened position)
Spool valve advantagesDIRECTIONAL CONTROL VALVES
The main advantage of spool valves is that fluid entering the valve from any working port does not affect spool movement. The poppet in a poppet valve can have pressure on one side and only a light spring on the other. This can result in premature movement of the poppet when pressure enters a port. In a spool valve, pressure always is applied to two equal opposing areas or the edge of a land. Thus pressure forces
Slide15Eng. Ahmed Saeed Eladly
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two equal opposing areas or the edge of a land. Thus pressure forces that could move the spool are cancelled or non-existent. This means that a spool valve can be shifted manually, electrically, mechanically, pneumatically, or hydraulically with the same force regardless of the operating pressure. Low-force solenoids can be used because the most they need to overcome is mechanical friction and light springs
Spool valve disadvantagesDIRECTIONAL CONTROL VALVES
Many spool valves are designed with metal-to-metal sliding fits. As a result, some fluid may bypass these seals. If this happens, an actuator may not hold its position if outside forces are applied. It also means wasted energy and resulting heat. (Many pneumatic valves use some sort of resilient seal in the body and/or on the spool to eliminate air leaks.) To reduce bypass, spool valves have land overlap, so as they
Slide16Eng. Ahmed Saeed Eladly
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leaks.) To reduce bypass, spool valves have land overlap, so as they start shifting to open a flow path, there is a delay before fluid starts flowing. The delay only lasts for milliseconds and does not cause a problem -- unless the cycle is very fast and/or there are several valve shifts per cycle.
Spool valve disadvantagesDIRECTIONAL CONTROL VALVES
Another time delay occurs when a spool shifts to the end of its stroke. There is often more movement than required for the flow needed. When the spool shifts back to center or to the opposite flow path, it consumes more time to travel the extra distance. This slows the cycle, especially when several valves are involved. Stroke limiters that control maximum spool movement can eliminate this delay, but are seldom
Slide17Eng. Ahmed Saeed Eladly
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maximum spool movement can eliminate this delay, but are seldom seen in actual practice. The common fix for these problems is to speed up traverse time by installing a larger pump. However, faster actuator movement can add shock and heat due to higher energy input.
4/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
No. of Positions
4
2=
No. of Ports
Slide18Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
4/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide19Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
4/2 D.C.V with two pistons principle
4/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide20Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
4/2 D.C.V with two pistons principle
4/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide21Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
4/2 D.C.V with three pistons principle
4/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide22Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
4/2 D.C.V with three pistons principle
4/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
No. of Positions
4
3=
No. of Ports
Slide23Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
4/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide24Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
4/3 D.C.V
4/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide25Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
4/3 D.C.V
4/2 Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide26Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
4/3 D.C.V
Methods of ActuationDIRECTIONAL CONTROL VALVES
Slide27Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
Methods of ActuationDIRECTIONAL CONTROL VALVES
Slide28Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Methods of ActuationDIRECTIONAL CONTROL VALVES
Slide29Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Methods of ActuationDIRECTIONAL CONTROL VALVES
Slide30Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Methods of ActuationDIRECTIONAL CONTROL VALVES
Slide31Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
Methods of ActuationDIRECTIONAL CONTROL VALVES
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Slide32Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Methods of ActuationDIRECTIONAL CONTROL VALVES
Slide33Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Methods of ActuationDIRECTIONAL CONTROL VALVES
Slide34Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
Methods of ActuationDIRECTIONAL CONTROL VALVES
Slide35Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Festo Hydraulic Manual
Methods of ActuationDIRECTIONAL CONTROL VALVES
Slide36Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Valve PositionsDIRECTIONAL CONTROL VALVES
Normal Position
Primary Position
Slide37Eng. Ahmed Saeed Eladly
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Ref: Festo Hydraulic Manual
Primary Position
Operational Position
Port LettersDIRECTIONAL CONTROL VALVES
P : PressureT : TankA : First output portB : Second output port
Slide38Eng. Ahmed Saeed Eladly
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Ref: Festo Hydraulic Manual
B : Second output port
Port LettersDIRECTIONAL CONTROL VALVES
Slide39Eng. Ahmed Saeed Eladly
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Overlap PositionDIRECTIONAL CONTROL VALVES
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Overlap PositionDIRECTIONAL CONTROL VALVES
Slide48Eng. Ahmed Saeed Eladly
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Mounting valvesDIRECTIONAL CONTROL VALVES
Slide49Eng. Ahmed Saeed Eladly
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Mounting valvesDIRECTIONAL CONTROL VALVES
Slide50Eng. Ahmed Saeed Eladly
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Mounting valvesDIRECTIONAL CONTROL VALVES
Slide51Eng. Ahmed Saeed Eladly
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Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide52Eng. Ahmed Saeed Eladly
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Ref: Rexroth Hydraulic Manual, Volume 1
Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide53Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Rexroth Hydraulic Manual, Volume 1
Directional Control ValveDIRECTIONAL CONTROL VALVES
Slide54Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com
Ref: Rexroth Hydraulic Manual, Volume 1
ActivityDIRECTIONAL CONTROL VALVES
Interpret the given hydraulic valve symbols
Slide55Eng. Ahmed Saeed Eladly
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ActivityDIRECTIONAL CONTROL VALVES
Design a hydraulic circuit to control the forklift
Slide56Eng. Ahmed Saeed Eladly
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THE ENDDIRECTIONAL CONTROL VALVES
Slide57Eng. Ahmed Saeed Eladly
http//:ASEladly.webs.com