Hydraulic Schematics

Function of a Hydraulic Schematic

• A hydraulic schematic illustrates how components in a fluid power circuit are connected, helping to understand circuit functionality and operation.
• Can be represented as pictorial diagrams (actual pictures) but are time-consuming to create and harder to use.
• Schematic diagrams provide a visual shorthand using symbols to represent different components, making them easier and quicker to draw.

Components of Hydraulic Schematic Diagrams

• Common elements represented in a schematic:
  • Tank/Reservoir: Holds hydraulic fluid.
  • Filter: Removes contaminants from the fluid.
  • Pump: Moves fluid through the system.
  • Electric Motor: Powers the pump or other components.
  • Pressure Relief Valve: Protects systems from excessive pressure.
  • Pressure Gauge: Measures fluid pressure.
  • Flow Control Valve: Regulates the flow rate of the fluid.
  • Directional Control Valve: Directs fluid flow within the circuit.
  • Double Acting Cylinder: Provides linear motion in two directions.

Flow Direction in Hydraulics

• The solid triangle symbol commonly indicates flow direction in hydraulic schematics.
• It can also represent a partial circuit where all components leading to the supply don’t need to be depicted.

Standards for Schematic Symbols

• Common standards for hydraulic schematic symbols include:
  • National Fluid Power Association (NFPA)
  • American National Standards Institute (ANSI)
  • International Organization for Standardization (ISO)
• ISO is easier to remember due to its Greek origin meaning 'equal'.
• The U.S. frequently uses NFPA and ANSI standards, while most other countries favor ISO.

Hydraulic Quick Connect Fitting

• Function:

  • Enables fast and easy assembly/disassembly of hydraulic circuits.
  • Common in applications requiring frequent disconnection of hoses.

• Structure:

  • Consists of a male fitting and a female fitting that snap together without needing special tools.
  • Each fitting includes a check valve to prevent oil leakage upon disconnection.

• Schematic Symbol: Representative symbol includes directed connection lines between male and female fittings.

Tee in Hydraulic Circuits

• Function:

  • Connects two different circuits to a single supply line using a fitting known as a 'T'.

• Schematic Symbol:

  • Depicted as a 'T', showing branching connections in the hydraulic circuit.
  • Can be configured with various combinations of male and female fittings.

Pressure Gauge in Hydraulics

• Function:

  • Often uses the Bordon tube gauge, which bends under pressure, moving a pointer along a scale.
  • Provides dual scale readings (US customary and SI units) for ease of use.

• Schematic Symbol: Depicted with a specific symbol representing pressure measurement components in the circuit.