Learning Objectives
Upon completing this chapter, you should be able to:
1. Explain the primary functions of a hydraulic fluid.
2. Define the term fluid.
3. Distinguish between a liquid and a gas.
4. Appreciate the properties desired of a hydraulic fluid.
5. Define the terms specific weight, density, and specific gravity.
6. Understand the terms pressure, head, and force.
7. Differentiate between gage pressures and absolute pressures.
8. Calculate the force created by a pressure. .
9. Understand the terms kinematic viscosity and absolute viscosity.
10. Convert viscosity from one set of units to another set of units.
11. Explain the difference between viscosity and viscosity index.
2.1 INTRODUCTION
The single most important material in a hydraulic system is the working fluid itself. Hydraulic fluid characteristics have a crucial effect on equipment performance and life. It is important to use a clean, high-quality fluid in order to achieve efficient hydraulic system operation.
Most modern hydraulic fluids are complex compounds that have been carefulh prepared to meet their demanding tasks. In addition to having a base fluid hvdi tube
fluids contain special additives to provide desired characteristics ' K