Potencia Fluida

1. INTRODUCTION

Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids. At a very basic level hydraulics is the liquid version of pneumatics. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. In fluid power, hydraulics is used for the generation, control, and transmission of power by the use of pressurized liquids. Hydraulic topics range through some part of science and most of engineering modules, and cover concepts such as pipe flow, dam design, fluidics and fluid control circuitry, pumps, turbines,hydropower, computational fluid dynamics, flow measurement, river channel behavior and erosion.

Ancient and medieval era

Early uses of water power date back to Mesopotamia and ancient Egypt, where irrigation has been used since the 6th millennium BC and water clocks had been used since the early 2nd millennium BC. Other early examples of water power include the Qanat system in ancient Persia and the Turpan water system in ancient China.

Greek / Hellenistic age

The Greeks constructed sophisticated water and hydraulic power systems. An example is the construction by Eupalinos, under a public contract, of a watering channel for Samos, the Tunnel of Eupalinos. An early example of the usage of hydraulic wheel, probably the earliest in Europe, is the Perachora wheel (3rd century BC).[2]

Notable is the construction of the first hydraulic automata by Ctesibius (flourished c. 270 BC) and Hero of Alexandria (c. 10 – 80 AD). Hero describes a number of working machines using hydraulic power, such as the force pump, which is known from many Roman sites as having been used for raising water and in fire engines.

China

In ancient China there was Sunshu Ao (6th century BC), Ximen Bao (5th century BC), Du Shi (circa 31 AD), Zhang Heng (78 - 139 AD), and Ma Jun (200 - 265 AD), while medieval China had Su Song (1020 - 1101 AD) and Shen Kuo (1031–1095). Du Shi employed a waterwheel to power the bellows of a blast furnace producing cast iron. Zhang Heng was the first to employ hydraulics to provide motive power in rotating an armillary sphere for astronomical observation.

Sri Lanka

In ancient Sri Lanka, hydraulics were widely used in the ancient kingdoms of Anuradhapura and Polonnaruwa.[3] The discovery of the principle of the valve tower, or valve pit, for regulating the escape of water is credited to ingenuity more than 2,000 years ago.[4] By the first century AD, several large-scale irrigation works had been completed.[5] Macro- and micro-hydraulics to provide for domestic horticultural and agricultural needs, surface drainage and erosion control, ornamental and recreational water courses and retaining structures and also cooling systems were in place in Sigiriya, Sri Lanka. The coral on the massive rock at the site includes cisterns for collecting water.

Innovations in Ancient Rome

In Ancient Rome many different hydraulic applications were developed, including public water supplies, innumerable aqueducts, power using watermills and hydraulic mining. They were among the first to make use of the siphon to carry water across valleys, and usedhushing on a large scale to prospect for and then extract metal ores. They used lead widely in plumbing systems for domestic and public supply, such as feeding thermae.

Hydraulic mining was used in the gold-fields of northern Spain, which was conquered by Augustus in 25 BC. The alluvial gold-mine ofLas Medulas was one of the largest of their mines. It was worked by at least 7 long aqueducts, and the water streams were used to erode the soft deposits, and then wash the tailings for the valuable gold content.

Modern era (c. 1600 – 1870)

Benedetto Castelli

In 1619 Benedetto Castelli (1576 - 1578–1643), a student of Galileo Galilei, published the book Della Misura dell'Acque Correnti or "On the Measurement of Running Waters", one of the foundations of modern hydrodynamics. He served as a chief consultant to the Pope on hydraulic projects, i.e., management of rivers in the Papal States, beginning in 1626.[6]

Blaise Pascal

Blaise Pascal (1623–1662) studied fluid hydrodynamics and hydrostatics, centered on the principles of hydraulic fluids. His inventions include the hydraulic press, which multiplied a smaller force acting on a smaller area into the application of a larger force totaled over a larger area, transmitted through the same pressure (or same change of pressure) at both locations. Pascal's law or principle states that for an incompressible fluid at rest, the difference in pressure is proportional to the difference in height and this difference remains the same whether or not the overall pressure of the fluid is changed by applying an external force. This implies that by increasing the pressure at any point in a confined fluid, there is an equal increase at every other point in the container, i.e., any change in pressure applied at any point of the fluid is transmitted undiminished throughout the fluids.

Jean Louis Marie Poiseuille

A French physician, Poiseuille researched the flow of blood through the body and discovered an important law governing the rate of flow with the diameter of the tube in which flow occurred.

2. Hydraulics

Hydraulic drills are a type of heavy equipment that can be used in a number of different construction, excavation, and drilling operations. Designed to bore through just about any type of substance, the hydraulic drill is commonly used in various types of excavating projects as well as drilling for oil or natural gas, or even as part of the process of scientific research of the earth. While drills of this type can be utilized in several different situations, the basic design remains the same.

There are actually two different types of these drills. One is the manual or hand-held hydraulic drill. This design makes it relatively simple to drill into the earth and collect soil samples. The samples can be used for geological analysis, or even for soil analysis before planting crops. These simple drills usually are equipped with an electric motor, a simple pump, and a tank to collect the samples.

An industrial hydraulic drill is usually mounted on some type of heavy machinery. Cranes may include a drill of this type when the idea is to loosen large amounts of soil for excavation. A hydraulic drill may be mounted onto the framing of an oil rig, making it easy to lower the drill into position and begin the process of boring into the ground in search of an oil deposit. Since drills of this type are capable of boring through just about any type of material, these heavy-duty designs can handle layers of rock and clay with the same ease that it can work through dirt.

Coolant is a common feature with hydraulic rock drills. This is necessary to prevent the drill from overheating during use. In some cases, water or some type of treated coolant is released in a slow but steady flow as the drill moves deeper into the ground. The liquid can aid in softening a layer of hard packed dirt, or even aid in making it easier to move through a layer of clay. This action helps to minimize the chances of the drill itself overheating and locking up during use.

As with any type of hydraulic equipment, a hydraulic drill must receive regular maintenance in order to operate at peak efficiency. Generally, the drill should be cleaned thoroughly after large projects, and inspected for any wear or tear on the shaft end of the drill. Any components that appear to be damaged or somewhat worn should be replaced before the next use. Simple maintenance and parts replacement will make it possible for the drill to remain in constant use for a number of years, which in turn helps to keep operational costs to a minimum.

A rock drill is a drilling device designed specifically for penetrating rock, for use in activities like digging wells, preparing foundations, and mineral exploration. A number of companies manufacture rock drills, often offering a lineup of several models to meet various needs. This equipment tends to be expensive and special training is required to use it. Drills can be leased, and operators can be hired by companies that do not have a full time need for a rock drill and operator.

Drilling through rock presents a challenge because the substrate is very hard. Ordinary drills can be damaged quickly. Rock drills feature especially hard bits made with materials like industrial diamonds, along with lubrication and cooling systems to limit stress caused by friction. The drill can also use an air blower to clear out the drilling hole as the drill penetrates, limiting damage to the drill caused by rock dust and other particulate materials.

Rock drills can be attached to drilling rigs for jobs when it's necessary to drill very deeply. They can also be manually controlled by an operator, in the form of a pneumatic rock drill with a throttle. In both cases, people must wear appropriate eye, ear, and facial protection when working around the drill. These drills are noisy, and inhaling rock dust or getting it in the eyes can be very uncomfortable. Drilling teams and personnel in the area usually wear facial screens and ear plugs to limit injuries associated with their work.

With rock drills for purchase, people may be able to rent or test several models before making a purchase decision. Drilling needs are highly variable, and since this equipment is expensive, companies usually want to make sure their customers are fully satisfied. In the case of leased drills, people can pay hourly or by the day, depending on the job, and can also request an operator to run the rock drill or

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