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Part I Fundamental Principles

The first part of this book is dedicated to the description of the fundamental laws, concepts, and conventions that are necessary to comprehend the functioning of hydraulic circuits and hydraulic components.

Chapter 1 contains a brief introduction of the hydraulic control technology and an explanation of the symbology used to illustrate hydraulic circuits.

Chapter 2 gives an overview of the properties of hydraulic fluids and how their properties can affect the operation of a component or a circuit. It also illustrates the detrimental effects of fluid cavitation, aeration, and contamination.

Chapter 3 recalls fundamental concepts derived from fluid mechanics, which are useful to describe the operation of fluid power components.

Subsequently, Chapter 4 is dedicated to the orifice, which is one of the most important conceptual elements of hydraulic control circuits. Orifices can have multiple functions and variable orifices can be used to describe the operation of many hydraulic components. The orifice equation will be repeatedly used throughout the manuscript.

Although the focus of the book is on the steady‐state operation of hydraulic machines and circuits, Chapter 5 introduces the reader to the basic analysis of transient operation of hydraulic circuits.

Objectives

Part I aims to familiarize the reader with the fundamental concepts and equations that will be used for the analysis of hydraulic circuits and hydraulic components. A reader already familiar with these concepts is still recommended to peruse the chapters of Part I, to be clear with the symbology and conventions used throughout the manuscript. After a thorough understanding of the contents presented in Part I, including the worked examples as well as the completion of the problems at the end of each chapter, the reader will be able to

1 Interpret circuits drawn with symbols of the ISO standard of representation.

2 Discuss the most common hydraulic fluids and describe the most important fluid properties affecting the operation of a hydraulic system.

3 Describe the concept of fluid cavitation or aeration and determine the effect on the fluid properties.

4 Describe the detrimental effects of solid contaminants in a hydraulic system.

5 Identify sources of energy loss, as turbulent or laminar hydraulic resistance.

6 Analyze flow forces in hydraulic components resulting from variation of fluid momentum.

7 Analyze the steady‐state operation of a flow network, based on the pressure law and flow law.

8 Derive the orifice equation starting from the fundamental Bernoulli equation.

9 Recognize the function of a specific orifice in a hydraulic network.

10 Discuss the concept of hydraulic resistance, hydraulic capacitance, and hydraulic inductance and their effects on the transient response of basic hydraulic systems.

11 Apply the concept of hydraulic resistance, hydraulic capacitance, and hydraulic inductance for basic analyses of hydraulic transients.