Hydraulic and Pneumatic Components: Functions and Types

Hydraulic Pumps: Boosting Suction and Discharge

• Constant High-Pressure Flow: A moving part (piston) is housed inside a casing.
• External-Tooth Gear Pump: Reverse rotation occurs at the entrance. There is a negative pressure difference that allows the transfer of the deposit to the inlet of the pump.
• Internal-Tooth Gear Pump: Features external teeth on the driving gear and internal teeth on the driven gear, along with a crescent-shaped plate.
• Lobe Pump: Similar to an external-tooth gear pump but designed for constant flow (unbalanced).
• Unbalanced Vane Pump: The rotor rotates within the volumetric ring and is located eccentrically.
• Balanced Vane Pump: The rotor and the ring are concentrically arranged, creating two zones of aspiration and discharge.

Pneumatic Compressors: Increasing Air Pressure

A compressor is a machine designed to increase the air pressure at the outlet.

• Piston Compressor:
  • Single-stage: Up to 5 bar
  • Two-stage: 5 to 10 bar
• Diaphragm Compressor: Diaphragm movement is triggered by a motor, obtaining eccentricity, and transmitted through a piston rod.
• Multicellular Compressor: The rotor rotates, driven by the motor shaft's eccentricity, and is located inside a housing.
• Screw Compressor: Up to 25 bar
• Roots Compressor: 1 to 2 bar

Hydraulic System Components

Filters

Eliminate solid particles and moisture.

Accumulators

Function as energy accumulators, anti-pulsation devices, anti-shock ram devices, leak compensators, and emergency auxiliary force providers.

• Counter-Accumulator: Stores fluid at a relatively constant pressure whether full or empty. A disadvantage is that they can generate overpressure.
• Spring-Loaded Accumulator: The fluid pressure is determined by the compression of the spring.

Tanks

Its function is to contain or store hydraulic fluid.

Valves

Direct and regulate fluid pressure and flow.

• Seat Valves: Present a challenge where the drive, in one of the valve's positions, must overcome the force exerted by the spring and the pressure.
• Slide Valves: Consist of a body containing a moving part and a series of internal passages.
• Slide and Cursor Valves: Communication between different connections is mediated by the action of a cursor (less wear).
• Rotational Valves: The rotor rotates 180 degrees for loading or unloading oil.

Directional Valve Centers

• Closed-Center: All ports are closed.
• Tandem-Center: In the central position, the working ports are blocked, so the system cannot be moved manually.
• Semi-Central: Connects the working lines with the tank line. The stem can be moved manually.
• Open-Center: All ports are connected.

Other Valve Types

• Gate Valves: The size of the hole is modified by rotating the valve stem, which moves a gate or wedge in the flow path.
• Globe Valves: The flow rotates 90° and passes through an opening where a plug or sphere is seated.
• Needle Valves