Fluid Power SystemsFluid Power Systems

Chapter 10Chapter 10

Advantages of Fluid Power Advantages of Fluid Power SystemsSystems

Almost unlimited power can be produced Almost unlimited power can be produced and maintainedand maintained

Easy and complete control (smooth, quick Easy and complete control (smooth, quick control of energy transfer)control of energy transfer)

A natural springiness that cushions and A natural springiness that cushions and reduces shock in the systemreduces shock in the system

Components can be at a distance with Components can be at a distance with quick power transfer and little power lossquick power transfer and little power loss

Fluids Exert PressureFluids Exert Pressure

Pressure is a force acting upon an areaPressure is a force acting upon an area Pressure is caused by the amount (weight) Pressure is caused by the amount (weight)

of liquid in a container (the column)of liquid in a container (the column) The more liquid present the more weight The more liquid present the more weight

(psi)(psi)

How Fluids ActHow Fluids Act

Water seeks its own levelWater seeks its own level Fluids flow from high pressure to low Fluids flow from high pressure to low

pressurepressure Flow continues until pressure is equal or Flow continues until pressure is equal or

balancedbalanced Balance happens when the fluid is levelBalance happens when the fluid is level

Blaise PascalBlaise Pascal

Pressure applied on a liquid in a container Pressure applied on a liquid in a container -- the pressure was distributed equally in -- the pressure was distributed equally in all directionsall directions

This pressure is multiplied by increasing This pressure is multiplied by increasing the action surface area (sq. in.) (Look at the action surface area (sq. in.) (Look at the example on Page 248.)the example on Page 248.)

Liquids Compared to GassesLiquids Compared to Gasses

Liquids compress so little they are Liquids compress so little they are considered not to compress considered not to compress

Gasses compress – this becomes the Gasses compress – this becomes the source of pressure in pneumatic systemssource of pressure in pneumatic systems

Robert Boyle – If temperature remains Robert Boyle – If temperature remains constant, increasing the pressure on a gas constant, increasing the pressure on a gas will reduce its volume. (2 x pressure = ½ will reduce its volume. (2 x pressure = ½ volume of gas)volume of gas)

Look at ComponentsLook at Components

Pages 232 – 245.Pages 232 – 245.

Begin with the Symbols.Begin with the Symbols.

PipelinesPipelinesRyan Way and Jeremy LedfordRyan Way and Jeremy Ledford

Private TreatmentPrivate Treatment

Sewage is piped out Sewage is piped out of your home. of your home.

P-traps are used to P-traps are used to block the gases from block the gases from coming back up from coming back up from the Septic tank.the Septic tank.

Septic TanksSeptic Tanks

Sewage from home Sewage from home runs into a septic runs into a septic tank.tank.

Made of concrete or Made of concrete or steel, solids sink to steel, solids sink to the bottom (D), scum the bottom (D), scum layer (B) flows outlayer (B) flows out

Drain FieldsDrain Fields

Water from septic Water from septic tanks flows out into tanks flows out into perforated pipes perforated pipes buried with gravel, buried with gravel, called drain fields.called drain fields.

Urban Wastewater SystemsUrban Wastewater Systems

Sewage is normally gravity powered.Sewage is normally gravity powered. Pipes from houses run into a sewer main Pipes from houses run into a sewer main

(usually 3 – 5 ft. dia.).(usually 3 – 5 ft. dia.). The main line flows to larger and larger The main line flows to larger and larger

pipes until it reaches a wastewater pipes until it reaches a wastewater treatment planttreatment plant

Lift StationsLift Stations

The land layout will The land layout will not always work for a not always work for a gravity powered gravity powered sewer system.sewer system.

In this case a grinder In this case a grinder pump or lift station will pump or lift station will move the water up or move the water up or over a hill.over a hill.

Treatment of SewageTreatment of Sewage

Once at the plant, the Once at the plant, the sewage goes through sewage goes through three stages of three stages of treatment.treatment.

1.) 1.) Primary treatment:Primary treatment: it acts the same way it acts the same way as a septic tank, the as a septic tank, the solids sink to the solids sink to the bottom and they are bottom and they are collected for disposal.collected for disposal.

Treatment cont…Treatment cont…

Secondary treatment:Secondary treatment: large aerated tanks large aerated tanks use help from use help from bacteria to eliminate bacteria to eliminate as many of the as many of the organic materials and organic materials and nutrients as possible.nutrients as possible.

Treatment cont…Treatment cont…

Tertiary Treatment:Tertiary Treatment: chemicals are used to chemicals are used to eliminate phosphorus and eliminate phosphorus and nitrogen from the water. nitrogen from the water. Any remaining bacteria is Any remaining bacteria is killed with chlorine. Water killed with chlorine. Water is then discharged.is then discharged.

(My hometown plant also (My hometown plant also used ultra-violet rays on used ultra-violet rays on the water before the water before discharging it.)discharging it.)

Water TowersWater Towers

Simply, a large Simply, a large elevated tank.elevated tank.

They provide They provide pressure. A typical pressure. A typical tower runs between tower runs between 50 and 100 PSI 50 and 100 PSI (major household (major household appliances require at appliances require at least 20 to 30 PSI).least 20 to 30 PSI).

Water Towers cont…Water Towers cont…

Usually located on Usually located on high ground, water high ground, water towers can hold up to towers can hold up to 1 million to 3 million 1 million to 3 million gal. of water!gal. of water!

They are sized to hold They are sized to hold around a day’s worth around a day’s worth of water for the of water for the community served by community served by the tower.the tower.

Water Towers cont…Water Towers cont…

Drinking water from Drinking water from wells, rivers, or wells, rivers, or reservoirs is treated reservoirs is treated to remove sediment to remove sediment and bacteria.and bacteria.

The water is The water is pressurized and sent pressurized and sent to the primary feeder to the primary feeder pipes. pipes.

Natural GasNatural Gas

First the gas is cleaned and separated. First the gas is cleaned and separated. Oils and hydrocarbons (butane, ethane, Oils and hydrocarbons (butane, ethane, and propane) are removed.and propane) are removed.

The gas is then pressurized to reduce the The gas is then pressurized to reduce the volume and achieve the necessary volume and achieve the necessary pressure to move it through the piping.pressure to move it through the piping.

Natural GasNatural Gas

Compressor substations are used to Compressor substations are used to account for the frictional pressure loss. account for the frictional pressure loss. They are usually every 50 to 100 miles.They are usually every 50 to 100 miles.

The gas will then be diverted to a “city The gas will then be diverted to a “city gate” where it is sold to the local gas gate” where it is sold to the local gas company which in turn sell it to their company which in turn sell it to their customers.customers.

ActivityActivity

Problem: How many liters of water will the 3 inch Problem: How many liters of water will the 3 inch PVC pipe hold?PVC pipe hold?

Volume: Volume: ΠΠ(radius)^2 X height of cylinder(radius)^2 X height of cylinder Volume: Base X Height X DepthVolume: Base X Height X Depth

Since one liter is 1000 cubic centimeters, and Since one liter is 1000 cubic centimeters, and there are 2.54 centimeters to one inch, there are 2.54 centimeters to one inch, conversion can be done simply with a calculator.conversion can be done simply with a calculator.

To find liters, divide cubic inches by 61To find liters, divide cubic inches by 61

AnswerAnswer

ΠΠ(1.5)^2 X 14.25 (1.5)^2 X 14.25 7.068583471 X 14.257.068583471 X 14.25 100.7273145100.7273145 cubic inches cubic inches ΠΠ(1.25)^2 X .5(1.25)^2 X .5 4.908738521 X .5 4.908738521 X .5 2.4543692612.454369261 cubic inches cubic inches 1.25 X 1.25 X 1.0 1.25 X 1.25 X 1.0 1.56251.5625 cubic inches cubic inches

AnswerAnswer

104.7441838 cubic inches104.7441838 cubic inches 104.7441838 / 61 to find liters104.7441838 / 61 to find liters 1.7171177671.717117767 liters liters