fluidpowerpoint_Chaptersp.1_lecture.pptx

chap 1

1. CHAPTER 1 INTRODUCTION TO FLUID POWER 1

2. 2 1. What is fluid power Contents 2. History of fluid power 3. Advantages of fluid power 4. Applications of fluid power 5. Components of a fluid power system 6. The fluid power industry

3. 1 What is fluid power? It is a technology that deals with Generation Control Transmission of power using pressurized fluids. It is the muscle of industry. Examples of application : Fluid power steers and brakes automobiles, launches spacecraft,harvests crops, mines coal, drives machine tools, controls airplanes, processes food, etc. 3

4. Fluid power – called hydraulics –fluid is liquid. Pneumatics when fluid is a gas. Liquids used- petroleum oils, synthetic oils and water First used was water; deficiencies-freezes, poor lubricant, corrodes metals. Pneumatics uses air because of abundance, can be exhausted back to the atmosphere. Two different types of fluid systems: fluid transport and fluid power Fluid transport-pumping system for water, cross country gas lines etc. Fluid power system-performs work; fluid cylinders 4

5. or motors. Cylinders and motors are also called actuators . Liquids easily transmit power – used for high pressure systems- high accuracy and precision. Because of compressibility effect, pneumatic systems limited to low pressure system. 5

6. 2 History of fluid power Fluid power is as old as civilization: water was used for centuries to produce power by means of water wheels, and air used to turn wind mills and propel ships. Limited use: because of low pressure fluid requiring large volume of fluid. Fluid power actually began in 1650 with the discovery of Pascal’s law: Pressure is transmitted undiminished in a confined body of fluid . Pascal’s experiment on a jug completely full of wine. 6

7. In 1750, Bernoulli developed his law of conservation energy for a fluid flowing in a pipeline. Pascal’ and Bernoulli’s law applied during the industrial revolution of 1850 to industry. Why not before? No electricity to power the machines of industry Fluid power (1870)was used to drive hydraulic equipments such as cranes, presses, winches, extruding machines, hydraulic jacks, shearing machines, etc. In these systems, the pressure was developed by steam engine driven pumps and distributed by pipes. There were central fluid power generating stations from which pressurized fluid was pumped to factories. 7

8. The early systems had a number of deficiencies such as the type of fluid, sealing problems etc. Then, late in the nineteenth century, electricity was found superior to fluid power and it replaced fluid power. Rebirth started in 1906-application on defense machines (to replace electrical systems for elevating and controlling military weapons) . For this application, the fluid power used hydraulic oil than water and significant improvement in sealing problems. 8

9. Today, fluid power is used extensively in every branch of industry. For example, automobiles, tractors, airplanes, boats, robots, machine tools etc. In the automobile: Hydraulic brake systems Automotive transmissions Power steering Power brakes Air conditioning Lubrication Water coolant Gasoline pumping systems 9

10. What is the role of modern technology? To improve the performance of fluid power using modern technology such as : 1. Electro-hydraulic systems, 2. Microprocessor 3. Improved materials for component construction Research and Development (R&D) is the key factor ! 10

11. 3 Advantages of fluid power Three basic methods of transmitting power: electrical , mechanical and fluid power . For example, longest distance of transmission; electricity followed by fluid and then mechanical. Most applications actually use a combination of the three methods to obtain the most efficient overall system Fluid power’s success and widespread use is its versatility and manageability: Not hindered by geometry as mechanical. Power can be transmitted in almost limitless quantities (unlike electrical systems) 11

12. Automation in industry best by fluid power because of advantages: Ease and accuracy of control : use of simple levers, and push buttons to stop, speed up or slow down, and position forces with preciseness to 1/5000 th -cm Multiplication of force : Can multiply forces simply and efficiently(no usage of gears, pulleys, and levers). eg . Construction machineries Constant force or torque : Only fluid powers capable of providing force or torque regardless of speed changes. E.g. Robots grabbing with a constant force. 12

13. Simplicity, safety, economy : Minimum use of moving parts (compared to mechanical and electrical). Maximizes safety, compactness, and reliability. fig-chp1\fig1.1.pptx System is fluid linked, no need for linkages, universal joints, bearings, reduction gears and so forth. Little input torque required to produce the steering control. 13

14. Drawbacks of fluid power In hydraulic systems, hydraulic oils are messy, leakage is impossible to eliminate completely, lines can burst resulting in injuries to people due to high speed oil jets and flying pieces of metals. Also, produce loud voice. Most hydraulic oils can cause fires. In pneumatic systems air tanks and accumulators are potentially explosive if pressure is not kept below design pressures. 14

15. 4. Applications of fluid power 15

16. Examples: 1. Sky trams : Tram travelling on a stationary cable, oil pump driven by a gasoline engine. The hydraulic motor drives friction drive wheels. On steep inclines, high driving torque is required for ascent and high braking torque for descent. 2. Harvesting corn : Hydraulic motor driven elevator conveyor system sends harvested, husked ears of corn to a wagon trailer. 3. Brush drives : fluid power is used as a brush drive for cleaning roads, floors, and so forth. 4. Industrial lift trucks : The fig-chp1\fig1.2a.pptx hydraulic system includes tilt and hoist cylinders. and fig-chp1\fig1.2b.ppt 16

17. 5. Excavators : A total of four hydraulic cylinders are used to drive the three pin-connected members called the boom , stick , and bucket . As much as 4 m 3 and a lifting capacity of about 20000kg is achievable fig-chp1\fig1.3.pptx . 6. Robotic dextrous arm : Robotic arm and fingers that can use human tools such as hammers, electric drills, and can even pick up an egg shell . fig-chp1\fig1.4.pptx 17

18. 5 Components of fluid power Hydraulic System: There are six basic components A tank (reservoir) to hold the oil A pump to force the oil through the system A power source to drive the pump (electric, others) Valves to control oil direction, pressure, and flow 5. An actuator to convert the oil pressure into force (cylinders) or torque (motors). Piping, which carries the oil from one location to another. fig-chp1\fig1.5.pptx and fig-chp1\fig1.6.pptx 18

19. Pneumatic Systems Again six basic components An air tank for storing compressed air A compressor to compress the air Power source for the compressor (electric, others) Valves to control air direction, pressure, and flow rate. Actuators, similar in operation to hydraulic actuators Piping to carry the pressurized air from one location to another 19

20. 6. The fluid power industry The fluid power industry is huge and truly a global industry. Annual sales world wide has exceeded $35 billion. Over half of all US industrial products have fluid power systems or components as part of their basic design. About 75% sales are hydraulic while the remaining 25% are pneumatic. 20