Force Transmission through a FluidForce Transmission through a Fluid

Unit TwoUnit Two

Force Transmission through a Solids, Force Transmission through a Solids, Liquids, and GasesLiquids, and Gases

Solids transmit force in only one direction Solids transmit force in only one direction but fluids transmit force in ALL directions.but fluids transmit force in ALL directions.

Force Transmission through Force Transmission through Solids, Liquids, and Solids, Liquids, and Gases(Continued)Gases(Continued)

Whereas liquids are relatively incompressible, Whereas liquids are relatively incompressible, gases will compress.gases will compress.

Force Transmission through a Force Transmission through a Solids, Liquids, and Solids, Liquids, and Gases(Continued)Gases(Continued)

Gases compress until their pressure is equal to the Gases compress until their pressure is equal to the force applied.force applied.

Fluids take the shape of their containerFluids take the shape of their container

The fact that fluids will take any shape gives them the The fact that fluids will take any shape gives them the property of unlimited conductive geometry.property of unlimited conductive geometry.

Pascal’s LawPascal’s Law

“Pressure set up in a fluid is transmitted equally and at right angles to all containing surfaces”

Applying PressureApplying Pressure

Pressure = Force/Area

An object at rest on the ground will develop An object at rest on the ground will develop pressure between itself and the point, or area, pressure between itself and the point, or area, where it meets the ground.where it meets the ground.

Area of a CircleArea of a Circle

The The area area of a circle is equal to the of a circle is equal to the diameterdiameter squared multiplied squared multiplied by by .7854.7854

Fluid pressure to Mechanical Fluid pressure to Mechanical ForceForce

A fluid under pressure is converted into another energy A fluid under pressure is converted into another energy form at the point of operation.form at the point of operation.

Fluid Fluid PowerPower Cylinders Cylinders

The actuator is where pressurized fluid is converted The actuator is where pressurized fluid is converted into mechanical force for performing work.into mechanical force for performing work.

How Cylinders WorkHow Cylinders Work

By allowing the fluid to contact a movable area, usually a piston, By allowing the fluid to contact a movable area, usually a piston, cylinders use the piston and rod to move a resistive object.cylinders use the piston and rod to move a resistive object.

Mechanical Force MultiplicationMechanical Force Multiplication

Actuators multiply force by applying pressurized fluid Actuators multiply force by applying pressurized fluid against a movable area that acts like a “lever.”against a movable area that acts like a “lever.”

Force = Pressure x AreaForce = Pressure x Area

Intensifier and Intensifier Intensifier and Intensifier OperationOperation

In operation, a intensifier is very much like a transformer. It In operation, a intensifier is very much like a transformer. It “steps” up pressure but reduces movement because of a difference “steps” up pressure but reduces movement because of a difference in volume.in volume.

How Intensifiers WorkHow Intensifiers Work

In practical operation, the intensifier is used for momentary In practical operation, the intensifier is used for momentary need of high pressure.need of high pressure.

Movement SacrificedMovement Sacrificed

You generally do not get something for nothing so when You generally do not get something for nothing so when Force is increased, something must decrease and that Force is increased, something must decrease and that will usually be movement.will usually be movement.

Pressure ScalesPressure Scales

For measuring pressure we have two different scales. One, For measuring pressure we have two different scales. One, PSIA, takes into account the weight of the atmosphere.PSIA, takes into account the weight of the atmosphere.

Measuring Atmospheric Measuring Atmospheric PressurePressure

The idea of the barometer is based on the observation of a liquid The idea of the barometer is based on the observation of a liquid with a specific weight being held back by the atmosphere. Every with a specific weight being held back by the atmosphere. Every

cubic inch of mercury exerts a weight of .491 pounds per inch.cubic inch of mercury exerts a weight of .491 pounds per inch.

Absolute Pressure ScaleAbsolute Pressure Scale

Since the weight of atmosphere is based on altitude at sea level, any Since the weight of atmosphere is based on altitude at sea level, any increase in land height will have a corresponding decrease in increase in land height will have a corresponding decrease in atmospheric pressure.atmospheric pressure.

Vacuum Pressure ScaleVacuum Pressure Scale

Vacuum is any pressure below “atmospheric” Vacuum is any pressure below “atmospheric” conditions.conditions.

How Vacuum is MeasuredHow Vacuum is Measured

Vacuum is measured on a gauge calibrated in inches of mercury so Vacuum is measured on a gauge calibrated in inches of mercury so it matches the barometer scale.it matches the barometer scale.

Pressure Gages and DesignPressure Gages and Design

Plunger designPlunger design Bourdon tube designBourdon tube design