Fluid Power Control

Module:03 ~ Hydraulic SYSTEM COMPONENTS FLUID POWER Module:03 ~ Hydraulic SYSTEM COMPONENTS Sources of Hydraulic Power Construction and working of pumps – Variable displacement pumps Actuators: Hydraulic cylinders, performing linear motion Hydraulic motors, performing continuous rotary motion Hydraulic rotary actuators, performing limited angular Control Components: Pressure Control Valve Direction control valve Flow control valves

FLUID POWER Control Components: Flow Control Valve

Control Components: FCV Functions of Flow-Control Valves: FLUID POWER Control Components: FCV Functions of Flow-Control Valves: Regulate the speed of linear and rotary actuators. Regulate the power available to the sub-circuits by controlling the flow to them. Proportionally divide or regulate the pump flow to various branches of the circuit

FLUID POWER Control Components: FCV Operation Principle:

Control Components: FCV Factors that determine flow rate: FLUID POWER Control Components: FCV Factors that determine flow rate: Cross-sectional area of orifice. Shape of the orifice (round, square or triangular). Length of the restriction. Pressure difference across the orifice (Δp). Viscosity of the fluid.

Control Components: FCV Operation Principle: FLUID POWER 4 LPM 6 LPM

Control Components: FCV Operation Principle: FLUID POWER 4 LPM 6 LPM

1. Non-pressure compensated 2. Pressure compensated FLUID POWER Control Components: FCV CLASSIFICATION: 1. Non-pressure compensated 2. Pressure compensated

Control Components: FCV Non-pressure compensated Needle Valve: FLUID POWER Non-pressure compensated Needle Valve:

FLUID POWER Control Components: FCV

Pressure Compensated FCV Control Components: FLUID POWER FCV Pressure Compensated Pressure Compensated FCV

Meter – in Circuit Control Components: FCV SPEED CONTROLLING CIRCUIT: FLUID POWER Control Components: FCV SPEED CONTROLLING CIRCUIT: Meter – in Circuit

Meter – out Circuit Control Components: FCV SPEED CONTROLLING CIRCUIT: FLUID POWER Control Components: FCV SPEED CONTROLLING CIRCUIT: Meter – out Circuit

Bleed – off Circuit Control Components: FCV SPEED CONTROLLING CIRCUIT: FLUID POWER Control Components: FCV SPEED CONTROLLING CIRCUIT: Bleed – off Circuit

Control Components: FCV Problem: 1 FLUID POWER Control Components: FCV SPEED CONTROLLING CIRCUIT: Problem: 1 A 55-mm diameter sharp-edged orifice is placed in a pipeline to measure the flow rate. If the measured pressure drop is 300 kPa and the fluid specific gravity is 0.90, find the flow rate in units of m3/s. Q in LPM, C = Flow coefficient = 0.80 for the sharp-edge orifice, = 0.6 for a square-edged orifice, A in mm2, Pressure drop in kPa

Control Components: FCV SPEED CONTROLLING CIRCUIT: FLUID POWER Problem: 2 The system shown in figure has a hydraulic cylinder with a suspended load W. The cylinder piston and rod diameters are 50.8 and 25.4 mm, respectively. The pressure-relief valve setting is 5150 kPa. Determine the pressure p2 for a constant cylinder speed: (a) W = 8890 N (b) W = 0 ( load is removed) (c) Determine the cylinder speeds for parts (a) and (b) if the flow-control valve has a capacity coefficient of . The fluid is hydraulic oil with a specific gravity of 0.90. ANS: 12700 kPa, 6880 kPa , 0.938 m/s , 0.691 m/s

Control Components: FCV SPEED CONTROLLING CIRCUIT: FLUID POWER Problem: 3 The system shown in figure has a hydraulic cylinder with a suspended load W. The cylinder piston and rod diameters are 50.8 and 25.4 mm, respectively. The pressure-relief valve setting is 5150 kPa. Determine the pressure p2 for a constant cylinder speed: (a) W = 8890 N (b) W = 0 ( load is removed) (c) Determine the cylinder speeds for parts (a) and (b) if the flow-control valve has a capacity coefficient of . The fluid is hydraulic oil with a specific gravity of 0.90. ANS: 12700 kPa, 6880 kPa , 0.938 m/s , 0.691 m/s