Hydraulic systems (1)

  • Term Paper on Hydraulic System

  • Presented by: Gopal Carpenter

  • Student ID: 12-543-008

Definition of Hydraulics

  • Derived from Greek words:

    • Hydor: water

    • Aulos: pipe

Necessity of Hydraulics

  1. To lift or load implements

  2. To set the draft during tillage operations

Pascal's Law

  • Pressure exerted at any point on a confined liquid is transmitted undiminished in all directions.

Basic Principle

  • Pressure applied to piston "A" is transferred equally to piston "B", keeping PSI consistent throughout the system.

Important Properties of Liquids

  • Shapelessness: Liquids take the shape of their container.

  • Incompressibility: Liquids return to original volume once force is removed.

  • Transmission of Force: Force is transmitted equally in every direction in a pressurized vessel.

Components of Hydraulics

  1. Reservoir

  2. Hydraulic pump

  3. Hydraulic cylinder

  4. Hydraulic piston

  5. Control valve

  6. Relief valve

  7. Lifting arms

Hydraulic Circuit

  • An interconnected set of discrete components that transport liquid.

Hydraulic Pumps

  • Function: Pressurize and move fluid within the system.

Types of Hydraulic Pumps

  1. Gear Pump

  2. Piston Pump

  3. Vane Pump

Gear Pumps

  • Fixed or constant displacement; effective at 1500 psi and below; fewer moving parts; cost-effective.

Piston Pumps

  • Effective at 2000 psi or more; consist of multiple pistons; complex with more moving parts.

  • Types include:

    1. Axial piston pump

    2. Radial piston pump

Vane Pumps

  • Effective at 1500 psi and below; include:

    1. Sliding vane

    2. Swinging vane

    3. Rolling vane

Hydraulic Cylinders

  • Convert hydraulic power into linear mechanical force.

  • Types:

    1. Ram cylinder

    2. Single acting

    3. Telescopic

    4. Spring return

    5. Double acting

Ram Cylinders

  • Simplest type; single fluid chamber; force applied in one direction; used in elevators and jacks.

Single Acting Cylinders

  • Similar to ram cylinders; includes a piston; leakage flows back to tank.

Telescopic Cylinders

  • Multiple rod segments; provides longer stroke; commonly used in compact spaces.

Spring Return Cylinders

  • Applied pressure extends the rod; spring retracts when pressure is released.

Double Acting Cylinders

  • Function under pressure at both ends; extension and retraction forces vary.

  • Tandem Cylinder: Two pistons with a shared rod for greater force without increasing bore size.

Control Valves

  • Direct fluid flow, regulate pressure, and control volume.

  • Types:

    1. Pressure valves

    2. Directional valves

    3. Volume/Flow control valves

Accumulators

  • Types include:

    • Piston

    • Bladder

    • Direct contact

Hydraulic Oil

  • Functions include:

    1. Compression

    2. Lubrication

    3. Sealing

    4. Cooling

Fluid Properties

  • Includes viscosity, thermal properties, specific gravity, lubricating ability, rust protection, fire resistance.

Filters for Hydraulic Lines

  • Essential for maintaining hydraulic system integrity.

Types of Hydraulic Systems

  1. Open center system

  2. Closed center system

Open-Center System

  • Pump continuously runs; oil flows through in neutral position.

Closed-Center System

  • Stops pumping during neutral; oil remains at full pressure.

Basic Hydraulic System Operation

  • Components include: Pump, Pressure Relief Valve, Reservoir, Directional Control Valve, Cylinder.

Thank You