1. Fluid Power Control

2. Module:05 ~ Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Module:05 ~ Hydraulic CIRCUITS & ANALYSIS
Single / Double Acting Cylinder Control,
Regenerative Circuit,
Pump Unloading Circuit
Double Pump Hydraulic System
Automatic Sequencing Of Two Cylinders.
Cylinder Synchronization Circuit
Speed Control Of A Hydraulic Motor
Circuit To Lift And Hold Heavy Load

3. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Hydraulic CIRCUITS & ANALYSIS
Single / Double acting cylinder control

4. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Regenerative circuit
To speed up while extending.
Retraction is same as a regular
double acting cylinder.
When DCV shifted to left envelope
flow from pump end regenerates
with pump flow to provide flow as:
QT = QP + QR,
With right envelope in action,
pump flow bypasses the DCV
Vp, ext = QP / AR
Vp, ret = QP / (AP -AR )
Load carrying capacity decreases:
Fload, ext = p AR
Fload, ret = p (AP - AR)
..\Fluid Power Simulator\Hydraulix\ct\Regenerative.ct

5. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Regenerative circuit : Drilling Machine Application
Operations Needed:
Rapid Spindle Advance
Slow Feed when drill starts
Retraction of Spindle
..\Fluid Power Simulator\Hydraulix\ct\Regenerative.ct

6. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Hydraulic CIRCUITS & ANALYSIS
Pump Unloading Circuit
Operation Features:
Unloading Valve opens as piston reaches the end of any strokes.
Check valve keeps high pressure oil in the pilot line of the Unloading Valve.
When valve shifts from left to right envelope, pilot line pressure reduces and ULV
resets itself.
..\Fluid Power Simulator\Hydraulix\ct\unloading.ct

7. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Pump Unloading Circuit
Operation Features:
Check valve is to protect Low pr pump.
Purpose of Relief valve is to protect high pr pump at the end of punching.
This circuit eliminates requirement of very expensive High Flow High Pressure pump.

8. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Pump Unloading Circuit
Unloading Circuit with ACCUMULATOR

9. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Unloading Valve
Application of unloading valve in a punching press
(High-Low circuit)

10. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Automatic Sequencing of Two Cylinders
Precaution:
Be aware of a premature second operation when clamping piston stalls or is stopped for any reason.
For personnel safety or to avoid product damage due to incomplete strokes, use limit switches, limit valves, or electronic controls
It may be assured by using directional control valves for each operation sequence.

11. Automatic Sequencing of Two
FLUID POWER
Automatic Sequencing of Two
Cylinders

12. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Cylinder Synchronization Circuit
Why do we need Synchronization of cylinders?
Features:
Cylinders connected in PARALLEL.
Cylinders are to be identical
Loads on the cylinders are also to be identical.

13. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Cylinder Synchronization Circuit
Cylinders connected in
SERIES.
Features:

14. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Speed Control of a Hydraulic Cylinder
To control the Extension Speed…
Meter-In Circuit

15. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Speed Control of a Hydraulic Cylinder
Meter-Out Circuit

16. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Meter-In ~vs~ Meter-Out

17. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Speed Control of a Hydraulic Cylinder
Can you make a Hydraulic Circuit in which the external load is assisting the piston movement, by one sequential valve & a check valve in parallel to it?

18. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Speed Control of a Hydraulic Motor

19. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Circuit To
Lift and Hold Heavy Load

20. Direction Control Valves:~ Check valves
FLUID POWER
Hydraulic ACTUATORS
Direction Control Valves:~ Check valves
A check valve is a two-way valve because it contains two ports. allows flow in one direction, but blocks the flow in the opposite direction.

21. Direction Control Valves:~ Check valves
FLUID POWER
Hydraulic ACTUATORS
Direction Control Valves:~ Check valves

22. Direction Control Valves:~ Check valves
FLUID POWER
Hydraulic ACTUATORS
Direction Control Valves:~ Check valves
Direction Sensitive Flow Rate
Application: Different actuator speeds can be achieved in both the directions.

23. DCV:~ Pilot operated Check valves
FLUID POWER
Hydraulic ACTUATORS
DCV:~ Pilot operated Check valves

24. Hydraulic VALVES A P L I C T O N
FLUID POWER
DCV:~ Pilot operated Check valves A P L I C T O N
In practice the leakage in control valve will allow the cylinder to creep.
Check valve would not have any leakage in closed position
Can’t we use a simple check valve to the schematic?

25. Hydraulic CIRCUITS & ANALYSIS
FLUID POWER
Circuit to lift and hold heavy load