Print this page Fluid Power (Part 1) – Hydraulic Principles
A. Bhatia, B.E.
Course Outline
Most modern machinery today uses fluid power principles to do work so as to make our lives easier. Think about your car's brakes and how, by stepping on the brake pedal, you apply stopping pressure on the brakes on all four wheels. The ease with which we drive and steer our cars today is because of fluid power. You see fluid power at automobile service centers lifting the cars so that mechanics can work underneath them, and many elevators are hydraulically-operated using the same technique. There are numerous such applications that rely on fluid power that are obviously very adaptable, but how do they actually work!
This 3-hr course provides a broad based understanding of the most important hydraulic concepts and introduces both Pascal's Law and Bernoulli's Principle. This course material is based entirely on the NAVEDTRA NONRESIDENT TRAINING COURSE 14105 titled “Fluid Power” wherein, the reader will be introduced to three chapters’ ----
Chapter -1: Introduction to Fluid Power
Chapter -2: Forces in Liquid
Chapter -3: Hydraulic Fluids
This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.
At the conclusion of this course, the student will:
- Understand the need for fluid power; advantages and application of fluid power with respect to type of production;
- Learn the behavior of liquids at rest and the factors affecting transmission of forces through liquids;
- Describe the fluid properties such as density, viscosity, flow rates, velocity, temperature, pressure, head and their relationships;
- Learn Pascal’s law and describe pressure and force in fluid power systems;
- Learn the behavior of liquids in motion and the factors involved in flow;
- Learn hydraulic principles – calculation of required pressure, required flow and required power;
- Understand the Bernoulli’s principle and learn how to calculate the fluid velocity or flow rate in a specified fluid system using the continuity equation;
- Understand the relationship of force, pressure and head;
- Understand the operation of basic hydraulic components and their application in hydraulic jacks and hydraulic brakes;
- Learn the quality of fluids acceptable for hydraulic systems;
- Learn about the general types of fluids – relative merits and demerits; and
- Learn the safety precautions when handling potentially hazardous fluids.
Intended Audience
This course is applicable to mechanical engineers, process engineers, automotive engineers, machine designers, constructors, mechanics, operators and others involved in design and operation of industrial machinery.
Benefit to Attendees
Attendee of this course will get to know more about the basic laws that apply to fluid power. The course will be extremely helpful to the amateur engineers who desire to build on their design experience and the skilled professionals who have learnt the trade informally on the job.
Course Introduction
Nearly all industrial processes require objects to be moved, manipulated or subjected to some sort of force. This is frequently accomplished by means of electrical, mechanical or fluid systems:
- Mechanical - clutches, gears, levers, etc.;
- Electrical - motors, switchgear, generators, etc.;
- Hydraulic - valves, pumps, motors, cylinders, etc.;
- Pneumatic - valves, compressors, etc.
Fluid Power is the controlled transmission of energy by oil or air - hydraulics or pneumatics. Hydraulic systems operate with pressurized liquids, pneumatics with compressed air. The course introduces three chapters’ from NAVEDTRA NONRESIDENT TRAINING COURSE 14105 titled “Fluid Power”:
Chapter -1: Introduction to Fluid Power
Chapter -2: Forces in Liquid
Chapter -3: Hydraulic Fluids
Course Content
This course is in the following PDF document:
Fluid Power (Part 1) – Hydraulic Principles
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Course Summary
Fluid power systems generate, transmit, and control applications of power by using pressurized and moving fluids within an enclosed circuit. The reason fluids can transmit energy when contained is best stated by Pascal's Law of fluid power which says: Pressure in a confined body of fluid acts equally in all directions and at right angles to the containing surfaces.
Work is the measure of a force traversing through a distance. (Work = Force X Distance.). Work usually is expressed in foot-pounds and, as the formula states; it is the product of force in pounds times distance in feet. When a cylinder lifts a 20,000-lb load a distance of 10 ft, the cylinder performs 200,000 ft-lb of work. This action could happen in three seconds, three minutes, or three hours without changing the amount of work.
When work is done in a certain time, it is called power. [Power = (Force X Distance) / Time]. Power is the rate of doing work. A common measure of power is horsepower; one horsepower is defined as the weight in pounds (force) to lift one foot (distance) in one second (time). One horsepower is equivalent to 550 lbs. one foot in one second or 33,000 ft-lb per minute.
The modern day applications of hydraulics and pneumatics are extremely diverse. The applications include:
- Automotive - suspensions, brakes, steering;
- Aerospace - rudders, ailerons, aircraft servicing, flight simulators;
- Mining equipment - diggers, graders, tippers, fork lifts, excavators cranes;
- Marine - drives and controls of ships;
- Off-shore - oil-rig and sub-sea inspection equipment;
- Civil engineering - dams and bridges;
- Theatre and leisure - stage controls, fairground and leisure park rides;
- Medical - hospital beds and operating tables.
Fluid power ensures safety, guarantees quality and reliability.
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
