Fluid Power Control

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

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

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

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

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

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.

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

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

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.

Automatic Sequencing of Two FLUID POWER Automatic Sequencing of Two Cylinders

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.

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

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

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

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

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?

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

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

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.

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

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.

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

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?

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