MSY 1 Fluid Power Application Physical Properties Hydraulics & Pneumatics KMD 3133

2 Objectives Understand; 1.Function -hydraulic fluid. 2.Term-fluid. 3.Distinguish-liquid,gas. 4.Define -weight, density and specific gravity. MSY

Objectives (cont…) 6.Pressure, head, and force. 7.Differentiate-gage pressure,absolute pressures. 8.Calculate-force,pressure. 8.Pascal’s law 3 MSY

4 Characteristics -crucial effect, application, performance,life. Characteristics -crucial effect, application, performance,life. Efficient-clean, high-quality Efficient-clean, high-quality Modern Hydraulic-complex,carefully Modern Hydraulic-complex,carefully Special additives-desired characteristics. Special additives-desired characteristics. INTRODUCTION HYDRAULICS FLUID

MSY 5 Hydraulics Fluid Introduction (4)four primary functions; 1.Transmitting power. 2.Lubricating moving parts. 3.Seal clearances between mating parts. 4.Dissipate heat.

Transmitting power MSY 6 Pump & Turbine

Lubricating moving parts MSY 7 Engine

EFFICIENCY OF FLUID 8 MSY

9 Properties Ensure-practical,safety,cost 1.Good Lubricity 2.Ideal viscosity 3.Chemical & environmental stability 4.Compatibility with system materials 5.High degree of incompressibility 6.Fire resistance MSY

Properties (cont…) 7.Good heat-transfer capability 8.Low density 9.Foam resistance 10.Non-toxicity 11.Low volatility 12.Inexpensive 13.Ready available 10 MSY

11 Properties In reality - no ideal In reality - no ideal Designers -closest to being ideal Designers -closest to being ideal Change periodically –viscosity & acidity increase Change periodically –viscosity & acidity increase MSY

Quality indicator 1.Viscosity. 2.Water content. 3.Foreign particle contamination level. 12 MSY

13 Fluids – Liquids Fluid-gases,liquids Fluid-gases,liquids Liquids – definite volume Liquids – definite volume Shape-container. Shape-container. MSY

14 Fluids – Liquids Incompressible Incompressible Change-small,ignored Change-small,ignored MSY

15 Fluids – Gases Gases –compressible. Gases –compressible. Volume-vessel containing them. Volume-vessel containing them. MSY

16 Fluids – Gases Volume-influence, pressure Volume-influence, pressure Increase -volume to decrease. Increase -volume to decrease. Air-commonin, expensive and readily available. Air-commonin, expensive and readily available. MSY

17 Fluids – Gases Advantages; 1.Fire resistant 2.Not messy 3.Can be exhausted back into the atmosphere. MSY

Disadvantages 1.Compressibility – not suitable for accurate positioning, rigid holding 2.Due to compressibility – tends to be sluggish. 3.Corrosive -O 2 and H Added to lubricant 5.Limited pressures -250 psi,explosion,compress create energy 18 MSY