Concept of Hydraulics & It's Application

Concept of Hydraulic Systems:

Hydraulics is a branch of science concerned with the practical applications of fluids, primarily liquids, in motion. It is related to fluid mechanics, which in large part provides its theoretical foundation.

Hydraulic systems, like pneumatic systems, are based on Pascal's law which states that any pressure applied to a fluid inside a closed system will transmit that pressure equally everywhere and in all directions. A hydraulic system uses an incompressible liquid as its fluid, rather than a compressible gas.

The popularity of hydraulic machinery is due to the substantial amount of power that can be transferred through small tubes and flexible hoses, the high power density and a wide array of actuators that can make use of this power, and the huge multiplication of forces that can be achieved by applying pressures over relatively large areas.

History:

-In 1648, Blaise Pascal (the unit of pressure’s namesake) realized that fluids exerted an equal force in every direction.

-In 1738, a Swiss mathematician called Daniel Bernoulli put this theory into practice. He used pressurized water in mills and pumps.

-Then in 1975, an Englishman called Joseph Bramah patented the first hydraulic press.

Principle:

Liquids in motion or under pressure did useful work for humanity for many centuries before French scientist-philosopher Blaise Pascal and Swiss physicist Daniel Bernoulli formulated the laws on which modern hydraulic power technology is based.

1. Pascal's Law:

Pascal’s principle, also called Pascal’s law, in fluid (gas or liquid) mechanics, states that in a fluid at rest in a closed container, a pressure change in one part is transmitted without loss to every portion of the fluid and to the walls of the container. The principle was first enunciated by the French scientist Blaise Pascal.

2. Bernoulli’s theorem:

The total mechanical energy of the moving fluid comprising the gravitational potential energy of elevation, the energy associated with the fluid pressure, and the kinetic energy of the fluid motion, remains constant.

Components of Hydraulic System:

Hydraulic systems typically include the following components:

1. Fluid - oil that moves throughout the system (typically petroleum)

2. Accumulator - stores energy with pressurized gas

3. Reservoir/receiver - holds excess fluid

4. Fluid filter - removes contaminants from the fluid

5. Pump/compressor - pumps the fluid through the system (can be manual or electric)

6. Pistons - create different pressure zones throughout the system

7. Motor - the power source for the pump

8. Control valves - controls the direction and flow rate of the fluid

9. Piping/tubing - allows the pressurized fluid to travel from one place to another

10. Actuator/cylinder - receives the fluid and converts the energy to do work

How does the hydraulic system work:

-In the hydraulic system, the force applied on fluid at one point gets transmitted through the connected components and enables some other point required for working.

-The fluid which may be water, petrol, or other liquid when pressurized acts on every part of the vessel creating power which is capable of lifting heavy loads.

-The reservoir is used to reserve the hydraulic fluid; it is well connected to the parts of machinery which need the power to be transmitted to them for working.

-While a hydraulic pump is used to transmit the hydraulic fluid to other parts of the system

-accumulator accumulates the energy created using pressurized fluids

-Actuator comprises of the cylinder, brakes, hydraulic motor, and hydrostatic transmission

-Generally speaking, the pressurized fluid creates power which is transmitted to different parts of the container vessel repeatedly which helps in doing repetitive tasks. At the construction site where the material is to be lifted again and again, the hydraulic system is put to use. The machine operator uses his hands to operate the machine.

Benefits of Hydraulic Systems:

1. Hydraulic systems are self-lubricating

2. Good power-to-weight ratio

3. Relatively small components

4. Easy and flexible transfer of energy with hydraulic pipes

5. Possibility to remove the actuation from hydraulic power generation due to easy transfer of hydraulic energy

6. The hydraulic systems can be controlled either manually or with modern electronics.

Disadvantages of Hydraulic System:

1. The cleanness of transmission fluids

2. The temperature dependant characteristics of fluids

3. Long-distance power transmission causes power losses in the system

4. The components and hydraulic fluids require maintenance at regular intervals

Applications of Hydraulic System:

1. Industrial Application: Some of the examples of industrial hydraulics are textile industry machinery, presses, loaders, crushers, plastic processing machinery, automated production lines, machine tool industry, steel making, and primary metal extraction applications

2. Marine Application: some of the examples of usage of hydraulics in the marine industry are steering gears, engine room maintenance including pumps and jacks, bow and stern thrusters, mooring drums, hatch covers, winches, etc.

3. Mining Application: Hydraulic fracturing is an advanced mining technology that is used for the extraction of unused gases and oils from beneath the earth’s surface. In this process, a high-pressure mixture of water, chemical additives, and sand is passed in the cracks to extract the required minerals.

4. Automobile Application: Some of the common applications of hydraulics in the automobile industry include power steering, windshields, brake, and shock absorbers.

5. Mobile Application: Some of the examples of mobile hydraulics are irrigation systems, tractors, material handling equipment, rail equipment, rail equipment, tunnel boring equipment, and building and construction equipment like excavators, cranes, earth moving equipment, and backhoe.

6. Aerospace Application: Rockets, airplanes, spaceships, etc. utilize a hydraulic system for retraction and extension of landing gears, adjusting wings, opening/closing doors, steering, and brakes.

Used of Hydraulic System:

1. Hydraulic Lifts and Fluid Power

2. Hydraulic Braking

3. Hydraulic Systems and Airplanes

4. Compressing Substances Using Fluid

Thanks for reading.

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