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Fluid Power Systems. Chapter 10. Advantages of Fluid Power Systems. Almost unlimited power can be produced and maintained Easy and complete control (smooth, quick control of energy transfer) A natural springiness that cushions and reduces shock in the system
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Fluid Power Systems Chapter 10
Advantages of Fluid Power Systems • Almost unlimited power can be produced and maintained • Easy and complete control (smooth, quick control of energy transfer) • A natural springiness that cushions and reduces shock in the system • Components can be at a distance with quick power transfer and little power loss
Fluids Exert Pressure • Pressure is a force acting upon an area • Pressure is caused by the amount (weight) of liquid in a container (the column) • The more liquid present the more weight (psi)
How Fluids Act • Water seeks its own level • Fluids flow from high pressure to low pressure • Flow continues until pressure is equal or balanced • Balance happens when the fluid is level
Blaise Pascal • Pressure applied on a liquid in a container -- the pressure was distributed equally in all directions • This pressure is multiplied by increasing the action surface area (sq. in.) (Look at the example on Page 248.)
Liquids Compared to Gasses • Liquids compress so little they are considered not to compress • Gasses compress – this becomes the source of pressure in pneumatic systems • Robert Boyle – If temperature remains constant, increasing the pressure on a gas will reduce its volume. (2 x pressure = ½ volume of gas)
Look at Components Pages 232 – 245. Begin with the Symbols.
Pipelines Ryan Way and Jeremy Ledford
Private Treatment • Sewage is piped out of your home. • P-traps are used to block the gases from coming back up from the Septic tank.
Septic Tanks • Sewage from home runs into a septic tank. • Made of concrete or steel, solids sink to the bottom (D), scum layer (B) flows out
Drain Fields • Water from septic tanks flows out into perforated pipes buried with gravel, called drain fields.
Urban Wastewater Systems • Sewage is normally gravity powered. • Pipes from houses run into a sewer main (usually 3 – 5 ft. dia.). • The main line flows to larger and larger pipes until it reaches a wastewater treatment plant
Lift Stations • The land layout will not always work for a gravity powered sewer system. • In this case a grinder pump or lift station will move the water up or over a hill.
Treatment of Sewage • Once at the plant, the sewage goes through three stages of treatment. • 1.) Primary treatment: it acts the same way as a septic tank, the solids sink to the bottom and they are collected for disposal.
Treatment cont… • Secondary treatment: large aerated tanks use help from bacteria to eliminate as many of the organic materials and nutrients as possible.
Treatment cont… • Tertiary Treatment: chemicals are used to eliminate phosphorus and nitrogen from the water. Any remaining bacteria is killed with chlorine. Water is then discharged. • (My hometown plant also used ultra-violet rays on the water before discharging it.)
Water Towers • Simply, a large elevated tank. • They provide pressure. A typical tower runs between 50 and 100 PSI (major household appliances require at least 20 to 30 PSI).
Water Towers cont… • Usually located on high ground, water towers can hold up to 1 million to 3 million gal. of water! • They are sized to hold around a day’s worth of water for the community served by the tower.
Water Towers cont… • Drinking water from wells, rivers, or reservoirs is treated to remove sediment and bacteria. • The water is pressurized and sent to the primary feeder pipes.
Natural Gas • First the gas is cleaned and separated. Oils and hydrocarbons (butane, ethane, and propane) are removed. • The gas is then pressurized to reduce the volume and achieve the necessary pressure to move it through the piping.
Natural Gas • Compressor substations are used to account for the frictional pressure loss. They are usually every 50 to 100 miles. • The gas will then be diverted to a “city gate” where it is sold to the local gas company which in turn sell it to their customers.
Activity • Problem: How many liters of water will the 3 inch PVC pipe hold? • Volume: Π(radius)^2 X height of cylinder • Volume: Base X Height X Depth • Since one liter is 1000 cubic centimeters, and there are 2.54 centimeters to one inch, conversion can be done simply with a calculator. • To find liters, divide cubic inches by 61
Answer • Π(1.5)^2 X 14.25 • 7.068583471 X 14.25 • 100.7273145 cubic inches • Π(1.25)^2 X .5 • 4.908738521 X .5 • 2.454369261 cubic inches • 1.25 X 1.25 X 1.0 • 1.5625 cubic inches
Answer • 104.7441838 cubic inches • 104.7441838 / 61 to find liters • 1.717117767 liters