NMU Hydraulics & Pneumatics Control Lecture 1 PDF

MEC273 HYDRAULICS & PNEUMATICS CONTROL Mohamed M. Tawfik Associate Professor, Faculty of Engineering, New Mansoura University, Egypt PhD, Cranfield University, UK LECTURE #1 1  RECOMMENDED REFERENCE M...

MEC273 HYDRAULICS & PNEUMATICS CONTROL Mohamed M. Tawfik Associate Professor, Faculty of Engineering, New Mansoura University, Egypt PhD, Cranfield University, UK LECTURE #1 1  RECOMMENDED REFERENCE Md. Abdus Salam, “Fundamentals of Pneumatics and Hydraulics”, 2022 Available FREE on EKB ►Springer ►e-books  COURSE TOPICS ▪ Introduction to Fluidic Control Systems ▪ Hydraulic Circuit Design ▪ Hydraulic System Basics ▪ Electrohydraulic Systems ▪ Hydraulic Pumps ▪ Case Studies and Industrial Applications ▪ Hydraulic Valves (Part 1) ▪ Introduction to Pneumatic Systems ▪ Hydraulic Valves (Part 2) ▪ Pneumatic System Components ▪ Hydraulic Actuators and Motors ▪ Electro-pneumatic Circuits and Control EVALUATION SYSTEM Final= 40 Marks Midterm= 20 Marks Total Evaluation Marks 100 Mini-Project= 20 Marks Quizzes= 20 Marks  EVALUATION SYSTEM Mini-Project=Suggested Topics Group Project Title Task Size 1.Hydraulic or Design and build a robotic arm using hydraulic or pneumatic actuators. Implement basic AI 2-3 Pneumatic Robot Arm algorithms (e.g., PID control, trajectory planning) to control the arm's movements. students 2.Hydraulic or Design and implement a control system for a specific aerospace manufacturing machine 3-4 Pneumatic Control (e.g., a drilling machine, a riveting machine). Explore the use of AI algorithms (e.g., students System for a Machine reinforcement learning, adaptive control) to optimize the control system's performance.. 3. Hydraulic or Design and build a system that can harvest energy from a hydraulic or pneumatic source. 3-4 Pneumatic Energy Explore the use of AI algorithms (e.g., energy optimization, predictive maintenance) to students Harvesting System improve the system's efficiency and reliability. 4.Hydraulic or Design and build a small-scale autonomous vehicle using hydraulic or pneumatic actuators. 4-5 Pneumatic Implement AI algorithms (e.g., computer vision, path planning, obstacle avoidance) to enable students Autonomous Vehicle the vehicle's autonomous operation.  TIMELINE EVALUATION CRITERIA Week# Announcing Total Mark = 20 1 Topics Forming 2 Groups Criterion Mark Registration 3 Form Starts Prototype Quality 4 4 Project Report Preparing Clarity & organization (4) 8 5 Writing quality (4) Projects Oral Presentation 6 Team collaboration (4) Clarity & organization (4) 8 Delivery of 7 Final Output 8 Evaluating Projects 9 10 Results INTRODUCTION am I studying this course ©Mohamed Tawfik 8 Faculty of Eng., New Mansoura University  AIRCRAFT SYSTEMS Landing gears Flight controls Door mechanisms PROPULSION SYSTEMS Engine starting systems Thrust reversers MANUFACTURING PROCESSES Hydraulic & Pneumatic systems are used They offer high power- to-weight ratios ©Mohamed Tawfik9 Faculty of Eng., New Mansoura University  Physical Principles & Fundamentals FLUID POWER PRINCIPLES ENERGY IN FLUID DIMENSIONS SYSTEMS & UNITS (Potential, Kinetic, Pressure) (Pressure, Flow, Power) FLUID PROPERTIES FLUID STATICS FLUID DYNAMICS (Density, Viscosity, (Pressure, Pascal’s Law, (Continuity, Bernoulli) Compressibility) Boyle’s Law) ©Mohamed Tawfik 10 Faculty of Eng., New Mansoura University  Physical Principles & Fundamentals Specific Specific Mass Density Weight Weight Gravity (m) (ρ) (W) (γ) ( SG ) kg γ = W/ V γ = m.g/ V SG = ρf / ρwater ρ=m/V W = m.g = ρ.g ≃ ρf/1000 kg/m3 N N/m3 — FLUID PROPERTIES (Density, Viscosity, Compressibility) ©Mohamed Tawfik 11 Faculty of Eng., New Mansoura University  Physical Principles & Fundamentals Viscosity Compressibility Dynamic ( μ ) Kinematic ( υ ) Compressible Incompressible IF Shear stress in fluid F/A μ the change in density with pressure μ= = υ= Velocity profile slope v/y ρ Significant Negligible N/m2.s m2/s =Pa.s ©Mohamed Tawfik 12 Faculty of Eng., New Mansoura University  Physical Principles & Fundamentals It states that: “Pressure exerted anywhere in a confined Pressure incompressible fluid is transmitted equally in Pascal’s Law all directions throughout the fluid such that the pressure variations remain the same.” p = F/A p1 = p2 F1/A1 = F2/A2 Pa p1 p2 F1 A2 A1 A2 = FLUID STATICS F2 A1 (Pressure, Pascal’s Law, Boyle’s Law) ©Mohamed Tawfik 13 Faculty of Eng., New Mansoura University  Physical Principles & Fundamentals It states that: It states that: “At a fixed temperature, the volume “Pressure exerted anywhere in a of gas is inversely proportional to confined incompressible fluid is Boyle’s Law the pressure exerted by the gas.” transmitted equally in all directions Pascal’s Law throughout the fluid such that the pressure variations remain the same.” p1 V1 = p2 V2 p1 = p2 p1 p2 A1 A2 ©Mohamed Tawfik 14 Faculty of Eng., New Mansoura University  Physical Principles & Fundamentals Continuity Eq. It represents the MASS CONSERVATION LAW Inflow D1 v1 v2 D2 Outflow 𝑚ሶ 1 = 𝑚ሶ 2 kg/s kg/s FLUID DYNAMICS 𝜌𝑉1ሶ = 𝜌𝑉ሶ2 (Continuity, Bernoulli) 𝜌𝐴1 𝑣1 = 𝜌𝐴2 𝑣2 ©Mohamed Tawfik 15 Faculty of Eng., New Mansoura University  Physical Principles & Fundamentals Bernoulli Eq. It represents the ENERGY CONSERVATION LAW p1 p2 Energy Forms Inflow v1 Z1 v2 Outflow Flow Potential Z2 ◄Reference Plane (Datum) Kinetic FLUID DYNAMICS (Continuity, Bernoulli) ©Mohamed Tawfik 16 Faculty of Eng., New Mansoura University  Physical Principles & Fundamentals Bernoulli Eq. It represents the ENERGY CONSERVATION LAW p1 p2 Energy Forms Inflow v1 Flow Z1 v2 Outflow Control Volume p p Force (F= p.A) Z2 p p ◄Reference Plane (Datum) 𝑥 Flow Energy = 9. 𝑥 =Volume (V) Flow Energy =𝑝. 𝐴. 𝑥 ∴ Flow Energy = 𝑝𝑉 ►NOTE: to get the Power within fluid power system, it is Flow Energy per unit time (J/s=W), i.e., Power = 𝑝𝑉ሶ ©Mohamed Tawfik 17 Faculty of Eng., New Mansoura University  Physical Principles & Fundamentals Bernoulli Eq. It represents the ENERGY CONSERVATION LAW p1 p2 Energy Forms Inflow v1 Flow (Pressure) v2 Outflow Z1 𝑝𝑉 Z2 Potential Kinetic ◄Reference Plane (Datum) 𝑚𝑔𝑍 0.5𝑚𝑣 2 The SUM (𝐸 ) is ALWAYS constant ©Mohamed Tawfik 18 Faculty of Eng., New Mansoura University  Physical Principles & Fundamentals Bernoulli Eq. It represents the ENERGY CONSERVATION LAW p1 p2 Energy Forms Inflow v1 The SUM (𝐸 ) is ALWAYS constant v2 Outflow Z1 𝐸 = 𝑝𝑉 + 0.5𝑚𝑣 2 + 𝑚𝑔𝑍 Z2 ◄Reference 𝑉 = 𝑚Τ𝜌 Plane (Datum) 𝑚𝑝 𝑚 𝑣2 𝐸= + + 𝑚 𝑔 𝑍 =Const. Joule 𝜌 2 ▼ ÷ 𝑚𝑔 𝑝 𝑣2 Flow Kinetic Potential 𝐸= + + 𝑍 =Const. m (Pressure) 0.5𝑚𝑣 2 𝑚𝑔𝑍 𝜌𝑔 2𝑔 𝑝𝑉 ©Mohamed Tawfik 19 Faculty of Eng., New Mansoura University  Physical Principles & Fundamentals Bernoulli Eq. It represents the ENERGY CONSERVATION LAW p1 Inflow v1 p2 The SUM (𝐸 ) is ALWAYS constant v2 Outflow Z1 Z2 𝑝 𝑣2 𝐸= + + 𝑍 =Const. m 𝜌𝑔 2𝑔 ◄Reference Plane (Datum) 𝑝1 𝑣12 𝑝2 𝑣22 + + 𝑍1 = + + 𝑍2 𝜌𝑔 2𝑔 𝜌𝑔 2𝑔 ▼ Bernoulli Equation in Flow Kinetic Potential 0.5𝑚𝑣 2 𝑚𝑔𝑍 the HEAD Form 𝑝𝑉 ©Mohamed Tawfik 20 Faculty of Eng., New Mansoura University HYDRAULIC vs. PNEUMATIC SYSTEMS  HYDRAULIC SYSTEMS PNEUMATIC SYSTEMS Incompressible liquids (usually oil) ◄ Working Fluid ► Compressible gases (usually air) ▲High (usually 1k-5k psi≈70-340 bar) ◄ Working Pressure ► ▼Low (usually 30-100 psi≈2-7 bar) ▲Higher efficiency over longer distances ◄ Power Transmission Efficiency ► ▼Lower efficiency over longer distances ▲Higher precision control ◄ Precision ► ▼Lower precision control ▲More sensitive (due to viscosity change) ◄ Temperature Sensitivity ► ▼Less sensitive ▲Higher initial & maintenance cost ◄ Cost ► ▼Lower initial & maintenance cost Complex, regular fluid change & filter replacement ◄ Maintenance ► Simpler, mainly filter changes Heavy machinery, aircraft control surfaces ◄ Typical Applications ► Assembly lines, pneumatic tools, robotics Hazard of fire risk due to flammable oils & high-pressure ◄ Safety ► Safer due to avoiding flammable fluids & low-pressure ©Mohamed Tawfik 22 Faculty of Eng., New Mansoura University APPLICATIONS IN AEROSPACE ENGINEERING 1. Flight Control Systems (Hydraulic) Image source: North Atlantic Industries ©Mohamed Tawfik 24 Faculty of Eng., New Mansoura University 2. Landing Gear System (Hydraulic) Image source: Armstrong, D. et al. (2013) - DOI ©Mohamed Tawfik 25 Faculty of Eng., New Mansoura University 3. Engine Starting Systems (Pneumatic) Image source: Aeronautics-Guide ©Mohamed Tawfik 26 Faculty of Eng., New Mansoura University MEC273 HYDRAULICS & PNEUMATICS CONTROL Mohamed M. Tawfik Associate Professor, Faculty of Engineering, New Mansoura University, Egypt PhD, Cranfield University, UK LECTURE #2 ©Mohamed Tawfik Faculty of Eng., New Mansoura University HYDRAULIC SYSTEM COMPONENTS ©Mohamed Tawfik Faculty of Eng., New Mansoura University  Hydraulic System Components Accumulator Hydraulic Power Unit (HPU) Motor Check Filter Valve Pump Directional Control Valve Actuator / Ram Reservoir / Sump / Tank 3 ©Mohamed Tawfik Faculty of Eng., New Mansoura University Hydraulic System Components ©Mohamed Tawfik 4 Faculty of Eng., New Mansoura University  Hydraulic System Components 1. Reservoir / Sump / Tank Breathing Vent Key Function(s) (Breather Cap) Filler Cap ▪ Hydraulic fluid storage ▪ Air Separation Shell ▪ Heat Dissipation Level ▪ Fluid Compensation Baffles ▪ Contaminant Sedimentation ▪ Reducing Turbulence (by Baffles) Drain Plug Symbol ► ©Mohamed Tawfik 5 Faculty of Eng., New Mansoura University  Hydraulic System Components 1. Reservoir / Sump / Tank Types Vented Pressurized Flexible Element Hybrid Type It is a reservoir that is open to It is a reservoir that maintains It is a reservoir that a flexible It is a reservoir that combines the atmosphere through a a positive pressure inside the bag or bladder housed in a features of both vented and vent (air breather). reservoir using compressed rigid outer container. The pressurized reservoirs. air, gas (e.g. N2). element expands & Pressurized Gas contracts with the Flexible Pressure fluid volume Control Changes. It is the most common type in It is used in mobile equipment It is common in aerospace & It is used where a balance industrial applications & some industrial applications some mobile applications between compact design & fluid cleanliness is needed. ©Mohamed Tawfik 6 Faculty of Eng., New Mansoura University  Hydraulic System Components 1. Reservoir / Sump / Tank Types Pressurized ≠ Flexible Element Pressurized Gas (From external pressure source) Pressurized Gas Enclosed Gas in the bladder (Compressed Air/N2) (with variable pressure) Typical Piston NO EXTERNAL Flexible Element to keep constant pressure expands/contracts pressure with change source based on fluid level in fluid level It typically need to be mounted in a specific orientation, usually upright ︽ ©Mohamed Tawfik 7 Faculty of Eng., New Mansoura University  Hydraulic System Components 1. Reservoir / Sump / Tank Types Pressurized ≠ Flexible Element Maintains a constant pressure on the Pressure may vary slightly as the flexible Operating principle► fluid regardless of fluid level. element expands or contracts. Intentionally pressurized. Not intentionally pressurized. Pressure source ► The system HAS external pressure source The system HAS NO external pressure source More complex, with pressure regulation Complexity ► systems and often safety relief valves Simpler design with fewer components Often uses a piston to separate the The flexible element forms a barrier Fluid-air interface► hydraulic fluid from the pressurizing gas between the fluid and the gas Uses a rigid tank with a gas-filled space The flexible bag/bladder itself expands Volume change response ► to accommodate volume changes. or contracts to handle volume changes. ©Mohamed Tawfik 8 Faculty of Eng., New Mansoura University  Hydraulic System Components 1. Reservoir / Sump / Tank Types Vented Pressurized Flexible Element PROS CONS Common PROS Common CONS 1. Simplicity 1. Contamination risk 1. Reduced cavitation risk (keeps +ve pressure on pump inlet) 1. ▲Complexity (require +components, pressure regulators) 2. Easy inspection 2. Fluid oxidation (at ▲T) 2. Better cleanliness (less disposed to contamination) 2. ▲Initial cost (expensive to manufacture than vented ones) 3. Easy air separation 3. Moisture ingress (▲RH%) 3. Better air separation (avoids fluid aeration) 3. ▲Maintenance cost (regular pressure checks & gas refills) 4. ▼Maintenance cost 4. Limited applications, 4. Compact design 4. ▲Safety concerns (overpressure hazard) 5. Good heat dissipation (can’t be used in 5. ▲Weight (heavier due to construction for pressure control) underwater/aerospace applications) 6. Energy inefficiency (require power usage to control pressure) PROS CONS PROS CONS 1. Orientation flexibility 1. Higher complexity 1. Simpler design 1. Orientation limitations 2. Constant +ve pressure 2. Increased cost 2. Lower cost 2. No constant +ve pressure 3. Pump cavitation prevention 3. Safety concerns 3. ▼ Weight 3. Capacity constraints (↓fluid) 4. Efficient air separation (due 4. Regular maintenance & 4. Reduced contamination 4. Degradation/punctures risk to increased pressure) pressure checks & gas refills 5. Auto-fluid volume adjust (@ harsh environment) 5. ▲Weight ©Mohamed Tawfik 9 Faculty of Eng., New Mansoura University  Hydraulic System Components 1. Reservoir / Sump / Tank Types Applications Vented Pressurized Flexible Element Stationary Cranes Aircraft Hydraulic Systems Automotive Systems (power steering/braking) Under-water/Marine Agricultural Equipment Medical Equipment Equipment Manufacturing Equipment Military Vehicles CNC Precise Machines ©Mohamed Tawfik 10 Faculty of Eng., New Mansoura University  Hydraulic System Components 1. Reservoir / Sump / Tank Vented Pressurized Flexible Element Orientation Stable, consistent orientation Can handle varying orientations Specific orientation required Orientation Operating Operating Conditions Clean environments Dusty or contaminated environments Moderately challenging environments Conditions Fluid Volume Fluid Volume Needs Large volumes used Compact, possible volume limitations Adaptive to changes, may have less capacity Needs Pump Inlet Pump Inlet Conditions Atmospheric pressure Positive pressure provided Slight positive pressure maintained Conditions System System Complexity Simple design, few components Complex, additional components needed Moderately complex Complexity Maintenance Maintenance Requirement Easy to maintain and clean Regular pressure checks, possible gas refills Periodic inspection of flexible element Requirement Initial Cost Lowest Highest Moderate Initial Cost Weight Weight Consideration Can be heavy for large volumes Heavy due to pressure-resistant construction Often lightest option Consideration Air Separation Air Separation Capability Limited Good Moderate Capability Temperature Temperature Sensitivity Least affected Affected by gas expansion/contraction May be sensitive to extreme temperatures Sensitivity Contamination Contamination Risk Highest risk Low risk Low risk Risk System Changes System Changes Adaptability Limited Can adapt through pressure adjustment Good adaptability to volume fluctuations Adaptability ©Mohamed Tawfik 11 Faculty of Eng., New Mansoura University Hydraulic System Components ©Mohamed Tawfik 12 Faculty of Eng., New Mansoura University  Hydraulic System Components 2. Filter Key Function(s) ▪ Removal of contaminant (such as: dirt, metal shavings, dust,..) ▪ Protection of sensitive components (such as: pumps, valves & actuators) ▪ Fluid life extension (i.e. reducing the frequency of fluid changes) ▪ Efficient system operation (since contaminants can ▲wear & ▼performance) ▪ Preventive maintenance (as filters act as an early-warning system for excessive wear in the system, indicating the potential source of wear by examining particles caught in them) Symbol ► ©Mohamed Tawfik 13 Faculty of Eng., New Mansoura University Hydraulic System Components ©Mohamed Tawfik 14 Faculty of Eng., New Mansoura University  Hydraulic System Components 3. Check Valve Key Function(s) ▪ Backflow prevention (avoiding reverse pressure in the circuit) ▪ Pump protection (avoiding cavitation and backpressure) ▪ Circuit isolation (by isolating different parts of the circuit, ensuring that pressure changes in a part don't affect others) Symbol ► Without a Spring With a Spring ©Mohamed Tawfik 15 Faculty of Eng., New Mansoura University  Hydraulic System Components 3. Check Valve Flow Direction Without a Spring Flow Direction With a Spring Flow Direction ` Flow Direction ©Mohamed Tawfik 16 Faculty of Eng., New Mansoura University  Hydraulic System Components 3. Check Valve Flow Direction Without a Spring Flow Direction With a Spring ©Mohamed Tawfik 17 Faculty of Eng., New Mansoura University  Hydraulic System Components 3. Check Valve Without a Spring With a Spring PROS CONS PROS CONS 1. ▼Pressure drop (No resistance to overcome). 1. May not seal as effectively at low pressures 1. Better sealing even with low back pressure 1. ▲Pressure drop (to overcome spring force) 2. Simpler design (Fewer parts = ▼ cost) 2. Sensitive to orientation (gravity affects) 2. Faster response time 2. More complex (more parts = ▲ cost) 3. Less likely to to mechanical failure 3. Slower response time (relies on back pressure) 3. Less sensitive to orientation 3. Potential for spring fatigue over time 4. Can handle high flow rates with ▼restriction 4. Chatter potential in pulsating flow conditions 4. Reduced chatter (spring dampens oscillations) 4. ▲More maintenance due to moving parts Applications Water Treatment Plants Aircraft Hydraulic Systems (▼Pressure drop is critical for efficient pumping operations) (Rapid response/closure is crucial for safety-critical operations) Agricultural Irrigation Systems Hydraulic Presses (Simple design is less prone to clogging with debris or deposits) (Ensures rapid & consistent closure, critical for press cycle times) ©Mohamed Tawfik 18 Faculty of Eng., New Mansoura University Hydraulic System Components ©Mohamed Tawfik 19 Faculty of Eng., New Mansoura University MEC273 HYDRAULICS & PNEUMATICS CONTROL Mohamed M. Tawfik Associate Professor, Faculty of Engineering, New Mansoura University, Egypt PhD, Cranfield University, UK LECTURE #3 ©Mohamed Tawfik Faculty of Eng., New Mansoura University HYDRAULIC SYSTEM COMPONENTS ©Mohamed Tawfik Faculty of Eng., New Mansoura University  Hydraulic System Components Accumulator Hydraulic Power Unit (HPU) Motor Check Filter Valve Pump Directional Control Valve Actuator / Ram Reservoir / Sump / Tank 3 ©Mohamed Tawfik Faculty of Eng., New Mansoura University Hydraulic System Components ©Mohamed Tawfik 4 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Key Function(s) Types ▪ Pressurization of Fluid Positive Displacement Dynamic Pumps ▪ Generation of Flow Pumps (Non-positive displacement) Symbol ► ©Mohamed Tawfik 5 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Types Positive Displacement Dynamic Pumps Pumps (Non-positive displacement) Operating Principle Operating They displace a fixed amount of fluid per revolution of pump shaft. Principle They use rotating impellers to move fluids by centrifugal force. (Flow) Operating They pressurize the fluid by increasing the fluid velocity initially at They pressurize the fluid by trapping a certain fluid amount and Principle the impeller exit, then the fluid is slowed down in the diffuser forcing it to the discharge. (Pressure) (casing), converting its kinetic energy into pressure energy. ©Mohamed Tawfik 6 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Types Positive Displacement Dynamic Pumps Pumps (Non-positive displacement) ▪ Can generate high pressure (70-350 bar & up to 700 bar). ▪ Can handle large flow rates (0.1-300,000 m3/h). Key ▪ Produce constant flow rate (regardless the pressure). ▪ Flow rate varies with discharge pressure. Characteristics ▪ Efficiency relatively constant over a wide range of viscosities. ▪ Efficiency is lower with highly viscous fluids. Reciprocating Rotary Radial Flow Axial Flow Typical Applications Hydraulic systems Food industries Water supply systems HVAC systems ©Mohamed Tawfik 7 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Positive Displacement Pumps Reciprocating Rotary Reciprocating Radial Axial Gear Pump Vane Pump Piston Pump Piston Pump Piston Pump Linear piston motion Pistons ⟂ Drive shaft Pistons // Drive shaft ©Mohamed Tawfik 8 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Reciprocating Piston Pump Linear piston motion Piston (Plunger) Outlet (Delivery) Valve Chamber Inlet (Suction) Valve ©Mohamed Tawfik 9 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Reciprocating Piston Pump Linear piston motion ©Mohamed Tawfik 10 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Reciprocating Piston Pump Linear piston motion ©Mohamed Tawfik 11 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Reciprocating Piston Pump Linear piston motion PROS CONS 1. Extremely high-pressure capability (1000+ bar) 1. Large size and weight 2. Excellent for handling viscous fluids 2. Significant pulsating flow 3. Good suction lift capabilities 3. Lower operating speeds 4. Simple design (for single-acting types) 4. Higher maintenance requirements Applications Oil and gas industry (well pumps) High-pressure cleaning equipment ©Mohamed Tawfik 12 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Positive Displacement Pumps Reciprocating Rotary Reciprocating Radial Axial Gear Pump Vane Pump Piston Pump Piston Pump Piston Pump Linear piston motion Pistons ⟂ Drive shaft Pistons // Drive shaft ©Mohamed Tawfik 13 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Radial PROS Piston Pump 1. High-pressure ability (up to >700 bar) Pistons ⟂ Drive shaft 2.at high pressures 3. Durability Outlet (Delivery) Valve 4. ▼Noise levels CONS 1. Heavier than axial piston pumps 2. Larger than axial piston pumps 3. Limited speed range 4. ▲Cost for lower pressure applications Inlet (Suction) Valve Applications Piston (Plunger) Machine tools High-pressure units (ex. Waterjet cutter) (ex. Hydraulic press) Shaft ©Mohamed Tawfik 14 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Positive Displacement Pumps Reciprocating Rotary Reciprocating Radial Axial Gear Pump Vane Pump Piston Pump Piston Pump Piston Pump Linear piston motion Pistons ⟂ Drive shaft Pistons // Drive shaft ©Mohamed Tawfik 15 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump PROS Axial 1. High-pressure ability (up to >350 bar) Outlet (Delivery) Piston Pump 2. ▲Efficiency Pistons // Drive shaft 3.Compact design Chamber Inlet (Suction) 4. Smooth operation Swash Plate CONS 1. More complex than other pump types 2. Can be noisy at high speeds Shaft 3. Higher initial cost Applications Aerospace hydraulics Automotive & Marine (ex. Automatic transmission) Piston (Plunger) ©Mohamed Tawfik 16 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Positive Displacement Pumps Reciprocating Rotary Reciprocating Radial Axial Gear Pump Vane Pump Piston Pump Piston Pump Piston Pump Linear piston motion Pistons ⟂ Drive shaft Pistons // Drive shaft ©Mohamed Tawfik 17 Faculty of Eng., New Mansoura University MEC273 HYDRAULICS & PNEUMATICS CONTROL Mohamed M. Tawfik Associate Professor, Faculty of Engineering, New Mansoura University, Egypt PhD, Cranfield University, UK LECTURE #4 ©Mohamed Tawfik Faculty of Eng., New Mansoura University HYDRAULIC SYSTEM COMPONENTS ©Mohamed Tawfik Faculty of Eng., New Mansoura University  Hydraulic System Components Accumulator Hydraulic Power Unit (HPU) Motor Check Filter Valve Pump Directional Control Valve Actuator / Ram Reservoir / Sump / Tank 3 ©Mohamed Tawfik Faculty of Eng., New Mansoura University Hydraulic System Components ©Mohamed Tawfik 4 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Positive Displacement Pumps Reciprocating Rotary Reciprocating Radial Axial Gear Pump Vane Pump Piston Pump Piston Pump Piston Pump Linear piston motion Pistons ⟂ Drive shaft Pistons // Drive shaft ©Mohamed Tawfik 5 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Gear Pump PROS 1. Simple & robust design Drive Gear 2. Lower initial & maintenance cost 3. High-pressure (100-300 bar) 4. Handles high-viscosity fluids well CONS 1. Relatively noisy operation 2. Higher internal leakage Inlet (Suction) Outlet (Delivery) 3. Limited pressure range in some designs 4. Can be affected by particulates Applications Lubricating oil Asphalt, bitumen Idler Gear transfer pumping ©Mohamed Tawfik 6 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Positive Displacement Pumps Reciprocating Rotary Reciprocating Radial Axial Gear Pump Vane Pump Piston Pump Piston Pump Piston Pump Linear piston motion Pistons ⟂ Drive shaft Pistons // Drive shaft ©Mohamed Tawfik 7 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Vane Pump PROS Sliding Vanes 1. Quieter operation 2. Lower internal leakage 3. More precise flow control Inlet (Suction) 4. Good for low-viscosity fluids CONS 1. More complex design 2. More maintenance required 3. Higher initial & maintenance cost 4. Lower pressure range (70 – 200 bar) Applications Rotor Outlet (Delivery) Power steering systems Precise CNC machines ©Mohamed Tawfik 8 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Positive Displacement Pumps Reciprocating Rotary Reciprocating Radial Axial Gear Pump Vane Pump Piston Pump Piston Pump Piston Pump Linear piston motion Pistons ⟂ Drive shaft Pistons // Drive shaft ©Mohamed Tawfik 9 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Fixed Displacement Pumps Variable Displacement Pumps These pumps displace a fixed amount of fluid per revolution These pumps displace a variable (adjustable) of pump shaft, regardless the system pressure. amount of fluid per cycle, based on system pressure Each cycle of the pump traps a fixed fluid volume They can modify their displacement by mechanical or and then forces it through the discharge. hydraulic means based on flow requirements. ©Mohamed Tawfik 10 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Fixed Displacement Pumps Variable Displacement Pumps FIXED for every cycle ◄Flow Rate► FLEXIBLE based on requirements NO flow control ◄Flow Control► Flow & pressure are CONTROLLABLE LESS efficient ◄Efficiency► MORE efficient Good for HIGH-PRESSURE systems ◄Usage► For VARIABLE PRESSURE systems ©Mohamed Tawfik 11 Faculty of Eng., New Mansoura University  Hydraulic System Components All can work as Fixed Displacement Pumps. 4. Pump Some can work as Variable Displacement Pumps. Positive Displacement Pumps Reciprocating Rotary Reciprocating Radial Axial Gear Pump Vane Pump Piston Pump Piston Pump Piston Pump Linear piston motion Pistons ⟂ Drive shaft Pistons // Drive shaft OFF ON ON OFF ON Fixed Displacement Available Variable Available Variable Fixed Displacement Available Variable ONLY Displacement Option Displacement Option ONLY Displacement Option ©Mohamed Tawfik 12 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Pump Control Systems ` ` Hydraulic Motor ` ` Out Flow = M Scenario 1 Driving Scenario 2 Pump M Motor STALL Out Flow = ZERO ◄Reservoir► M STALL: is the case where an overload affects the hydraulic element (pump/cylinder) causing it to slow-down or completely stop. ©Mohamed Tawfik 13 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Pump Control Systems Scenario 3 ` ` The flow rate is maintained Constant ` ` The PUMP is SAFE Out Flow = BUT M What about Power Consumption/Efficiency ? Scenario 1 Relief Valve ` Scenario 2 ` ` ` STALL ` STALL Out Flow = Out Flow = ZERO M M ©Mohamed Tawfik 14 Faculty of Eng., New Mansoura University  Hydraulic System Components 4. Pump Pump Control Systems Aim Pump Control Systems aim to regulate pump operation to meet changing system demands while ensuring efficient and safe operation Control Strategies Fixed Displacement (FD) Pumps Variable Displacement (VD) Pumps The control systems rely on pressure relief valves to maintain The control systems rely on adjusting the displacement based desired pressure levels. They can also use pressure on real-time demand, using load-sensing systems, pressure compensators and flow regulators. compensators and flow regulators. Pump Control Systems Key Components ◄ Pressure Compensator Flow Regulator ► ◄ Load-Sensing Control Relief Valve ► ©Mohamed Tawfik 15 Faculty of Eng., New Mansoura University