Fluid Mechanics and Syringe Mechanisms Notes

Force Multiplier

• A small force applied to a narrow piston is transmitted through a plastic tube to a wider piston.
• Pressure remains constant, but acts over a larger area, increasing the force while reducing the distance moved.
• This system is called a force multiplier.

Pascal's Principle

• Any pressure applied to a fluid in a closed system is transmitted equally in all directions throughout the fluid.

Force Production by a Piston

• The force produced by a piston depends on:
  • Area of the piston surface (in $mm^2$).
  • Pressure applied to push it (in $N/mm^2$).

Mechanical Advantage (MA)

• $Mechanical \, advantage(MA) = \frac{Load \, or \, Output \, force}{Effort \, or \, Input \, force}$
• $MA = \frac{Pressure \times area \, of \, output \, piston}{Pressure \times area \, of \, input \, piston}$
• $MA = \frac{Area \, of \, output \, piston}{Area \, of \, input \, piston}$ (since pressure is the same)

Force Calculation

• $Force = pressure \times area$
• Force acting on the narrow piston is the input (effort).
• Force acting on the wider piston is the output (load).
• Increasing pressure or area on the slave cylinder increases the force produced.

Syringe Mechanisms: Force Transfer

• Pneumatic systems use compressed air to lift a force.
• Hydraulic systems use liquid (oil) under pressure.
• Air can be compressed, but liquids cannot.
• Involves moving pistons in cylinders to create linear movement.
• The syringe providing the pressure is called the input cylinder.
• The syringe providing the movement is called the output cylinder.