Technology & Engineering
Hydraulics
Hydraulics is a branch of engineering that focuses on the mechanical properties of liquids, particularly water and oil. It involves the use of fluid power to generate, control, and transmit energy, typically through the use of pumps, valves, and actuators. Hydraulics is widely used in various applications, including construction equipment, manufacturing machinery, and aerospace systems.
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7 Key excerpts on "Hydraulics"
- Frank R. Spellman(Author)
- 2013(Publication Date)
- CRC Press(Publisher)
9.1 WHAT IS WATER Hydraulics? The word “Hydraulics” is derived from the Greek words hydro (“water”) and aulis (“pipe”). Originally, the term referred only to the study of water at rest and in motion (flow-ing through pipes or channels). Today, it is taken to mean the flow of any liquid in a system. What is a liquid? In terms of Hydraulics, a liquid can be either oil or water. In fluid power systems used in modern industrial equipment, the hydraulic liquid of choice is oil. Some common examples of hydraulic fluid power systems include automobile braking and power steering systems, hydraulic elevators, and hydraulic jacks or lifts. Probably the most familiar hydraulic fluid power systems in water/ wastewater operations are those in dump trucks, front-end loaders, graders, and earth-moving and excavation equip-ment. In this text, we are concerned with liquid water. Many find the study of water Hydraulics difficult and puz-zling (especially the licensure examination questions), but we know it is not mysterious or incomprehensible. It is the function or output of practical applications of the basic prin-ciples of water physics. Because water/wastewater treatment is based on the principles of water Hydraulics, concise, real-world training is necessary for operators who must operate the plant and for those sitting for state licensure/certification examinations. 9.2 BASIC CONCEPTS Air pressure (at sea level) = 14.7 pounds per square inch (psi) This relationship is important because our study of Hydraulics begins with air. A blanket of air many miles thick surrounds the Earth. The weight of this blanket on a given square inch of the Earth’s surface will vary according to the thickness of the atmospheric blanket above that point. As shown above, at sea level the pressure exerted is 14.7 pounds per square inch (psi). On a mountain top, air pressure decreases because the blanket is not as thick.
eBook - PDFSpellman's Standard Handbook for Wastewater Operators
Volume II, Intermediate Level, Second Edition
- Frank R. Spellman(Author)
- 2010(Publication Date)
- CRC Press(Publisher)
When studying “modern” water Hydraulics, it is important to remember that the science of water Hydraulics is the direct result of two immediate and enduring problems: “the acquisition of freshwater and access to a continuous strip of land with a suitable gradient between the source and the destination” (Magnusson, 2001, p. 36). 48 Spellman’s Standard Handbook for Wastewater Operators: Volume II, Intermediate Level 2 .1 WHAT IS WATER Hydraulics? The word “hydraulic” is derived from the Greek words hydro (“water”) and aulis (“pipe”). Originally, Hydraulics referred only to the study of water at rest and in motion (the flow of water in pipes or chan-nels). Today, it is taken to mean the flow of any liquid in a system. What is a liquid? In terms of Hydraulics, a liquid can be either oil or water. In the fluid power systems used in modern industrial equipment, the hydraulic liquid of choice is oil. Some common examples of hydraulic fluid power systems include automobile braking and power steering systems, hydraulic elevators, and hydraulic jacks or lifts. Probably the most familiar hydraulic fluid power systems in water/wastewater operations are those used on dump trucks, front-end loaders, graders, and earth-moving and excavation equipment. In this text, though, we are concerned with liquid water. Many find the study of water Hydraulics difficult and puzzling (espe-cially the licensure examination questions), but it is not all that mys-terious in that it involves practical applications of the basic principles of water physics. Because water/wastewater treatment is based on the principles of water Hydraulics, concise, real-world training is necessary for operators who must operate the plant and for those sitting for state licensure/certification examinations. 2 .2 BASIC CONCEPTS Air Pressure (at sea level) = 14.7 pounds per square inch (psi) The relationship shown above is important because our study of Hydraulics begins with air.
eBook - PDF- Sparrow Consulting(Author)
- 2021(Publication Date)
- Future Managers(Publisher)
Hydraulic systems can perform major functions with very small input energy required. According to Pascal’s law, you can use hydraulic fluid, which is almost incompressible, to transfer energy from one point to another. The following are the major components used in a hydraulic system: • Hydraulic fluid • Reservoirs • Pumps • Valves • Actuators. Some of the more important reasons you use a hydraulic system to transfer energy are as follows: • It provides a very good power amplification. • It evenly distributes power in any direction. • It is mechanically safe and easy to control and can be compact. The theory behind hydraulic systems includes the following: • Fluidity: This refers to a fluid that can flow easily and will take the shape of its containing vessel. • Pascal’ law: The pressure of any fluid (liquid or gas) applies a force that is equal in all directions against the sides of the container it is in. • Bernoulli’s theorem: Without energy added to a fluid or system, any increase in velocity will have a decrease in pressure and/or density. • System pressures: The pressure in the fluid at any part of the hydraulic system will depend on the lowest resistance to the outlet or escape of fluid from that part of the system to the lower part. eLink Visit this link to learn more about hydraulic systems: bit.ly/HydraulicCircuit Definitions Incompressible – cannot be compressed Reservoir – container to hold or store fluids 165 N4 Mechanotechnics|Hands-On! 7.1 Basic principles of fluid statics Fluid mechanics is the study of forces and the flow of water. It can be divided into two categories: • Fluid statics: The study of fluids at rest (zero velocity) and the effect of force • Fluid dynamics: The study of fluids in motion, which considers forces and flow principles. The basic principles of static fluid include pressure distribution and the effect it has on surfaces. The pressure distribution is caused only by the weight of the fluid.
eBook - PDFHydraulics and Fluid Mechanics
Proceedings of the First Australasian Conference Held at the University of Western Australia, 6th to 13th December 1962
- Richard Silvester(Author)
- 2014(Publication Date)
- Pergamon(Publisher)
At the time of my first efforts in this direction, the term mechanics of fluids had only recently been introduced into the States by my superior, Boris A. Bakhmeteff, and a considerable amount of missionary work had to be done before American hydraulicians began to recognize the advantages to be gained by the combination of analytical and experimental me-thods. Those of the Freeman scholars who had studied with members of the Ludwig Prandtl school in Germany, and in particular those who came under Theodor von Karman's influence later in America, were most effective in this regard. Today the methods of fluid mechanics are embodied in essentially every science in any way involving fluid motion, from astronomy to zoology, and in its modern applications the subject encompasses such a vast field that Hydraulics, which once played a parental role, is now very small in comparison with the far more responsible offspring that it helped to beget. I thus adhere to the term Hydraulics to indicate the specific branch of fluid mechanics that is of primary interest to most of the participants in this conference. Note, if you please, that I also distinguish between Hydraulics as an engineering science ON THE ART OF ADVANCING THE SCIENCE OF Hydraulics 3 and hydraulic engineering as its field of application. We are here concerned with the art of advancing the science rather than the art of utilizing it. I believe that those who organized the conference program thought that I might give some useful advice with regard not only to teaching and research but particularly to the planning of further conferences. They may have felt, perhaps, that certain similarities exist between our situation in America 30 years ago and that here today. I grant that we have had, in the intervening years, a number of successes and failures which might well be considered by any organization before proceeding very far with its own plans.
eBook - PDFFluid Power Circuits and Controls
Fundamentals and Applications
- John S. Cundiff(Author)
- 2001(Publication Date)
- CRC Press(Publisher)
15 2 Fluid Power Basics 2.1 Introduction Fluid power systems are designed using all the principles learned in fluid mechanics. It is appropriate to briefly review these principles before proceed-ing with our study of the applications. It is required that a student who reads this treatment of fluid power have had an undergraduate course in fluid mechanics. One of the underlying pos-tulates of fluid mechanics is that, for a particular position within a fluid at rest, the pressure is the same in all directions. This follows directly from Pas-cal’s Law. A second postulate states that fluids can support shear forces only when in motion. These two postulates define the characteristics of the fluid media used to transmit power and control motion. Traditional concepts such as static pressure, viscosity, momentum, continuity, Bernoulli’s equation, and head loss are used to analyze the problems encountered in fluid power sys-tems. The reader should continuously keep in mind that the fundamental concepts are being applied. New methodology is used, but no new concepts are introduced. Dimensions and units provide the engineer with a convenient method to track the progress of, and report the results of, analyses. Today, there is a tran-sition occurring in the U.S. from English to metric systems of units. While the scientific community universally embraces the metric system, trade contin-ues to occur in the English system of units in some places. Engineering stu-dents must be competent working in both U.S. Customary units and the metric SI (from the Le Système International d’Unités ), which is also known as the International System . Perhaps the main difficulty encountered by young engineers is handling mass versus force. For example, in the U.S. Customary system, it is custom-ary to weigh objects and report the magnitude of force generated by the object in the Earth’s gravitational field. On the other hand, the SI system of measurements relies on determination of mass directly.
eBook - PDF- Frank Yeaple(Author)
- 1995(Publication Date)
- CRC Press(Publisher)
10 Hydraulic and Electrohydraulic Applications Hydraulic power is unique in that the fluid medium, a liquid, is pumped under high pressure to perform work remotely at any location connectable by pipe or high-pres-sure hose. The force and power reside in the flowing fluid and can be applied directly, which is what makes Hydraulics indispensable in certain applications. Electrical power, by contrast, needs conductive windings at every work point to convert current flow into force and motion. There is no way, short of extremely high currents, that electrical actuators can produce the force per unit volume easily obtain-able in a high-pressure hydraulic actuator. THE WORKING DEVICES Hydraulic actuators and drives include cylinders, motors, and combination pump-mo-tor drives. Theory and design of the individual devices are covered in Chapters 3-8. Applications chosen here fall into these general categories: vehicles and transports, materials handling, earthmoving equipment, in-plant machinery, robotics, aerospace, marine, geothermal, hydronic heating, and extreme-pressure Hydraulics. At the end of the chapter are brief discussions of a variety of other interesting applications. POWER, FORCE, VELOCITY, POSITION Whatever the application, each of the actuators and drives may be broadly categorized by its primary purpose in that application: controlling power, creating force or torque, creating rotation or linear motion, or establishing position. Much development effort has gone into the control of power-type hydrostatic drives, particularly the closed-circuit configuration, and attention usually is focused on the pumps in these systems. The pump (and its pressure, flow, or load compensator) determines the basic characteristics of the drive; the motor is merely the output device, selected to match the load speed and torque requirements to the flow and pressure ca-pabilities of the pump. Power transmission eff iciency and smoothness are the main 275
- George E. Totten, Victor J. De Negri(Authors)
- 2011(Publication Date)
- CRC Press(Publisher)
1.2 HYDROMECHANICAL PRINCIPLES Essentially, a hydraulic system consists of mechanical parts operating together with a hydraulic fluid. Hence, its behavior is described by the classic laws of both mechanics and fluid mechanics. Although it is not the focus of this text, it is important to remember that several hydraulic compo-nents comprise electromechanical converters, such as solenoids, linear motors and torque motors and/or electro-electronic systems like sensors, power amplifiers and controllers. Therefore, the prin-ciples of electricity, electronics and electro-magnetism are also required for their modeling. 1.2.1 H YDROSTATICS : P ASCAL ’ S P RINCIPLE Fluids (gases or liquids) are compressible, which means that their mass density varies with the pressure to which they are submitted. Consequently, an abrupt local pressure variation will be propagated through the fluid with a velocity equal to the fluid sound velocity until the equilibrium has been re-established. This means that the fluid will have a dynamic behavior alternating between the two equilibrium states. When a fluid is treated as incompressible it is assumed that a local pressure perturbation is instantaneously transmitted throughout the fluid. This means that considering a fluid as being com-pressible or incompressible is dependent on the observer’s viewpoint and its validation depends on the use of the system and the particular design or analysis that is being carried out. Pascal’s principle states that “a change in the pressure of an enclosed incompressible fluid is conveyed undiminished to every part of the fluid and to the surfaces of its container” [1,7]. Hence, when a fluid is in a state of equilibrium, that is, in a steady state, the whole system is under the same internal pressure. The practical use of Pascal’s principle can be exemplified by the hydrostatic press principle whose objective is to amplify the force.
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