Basic Hydraulics Module 1

Basic Hydraulics Module 1

• This module covers basic hydraulics, safety, and components.
• Hydraulics uses pressurized fluid to transmit power.
• Safety is crucial, including appropriate PPE, lifting techniques, and oil disposal procedures.

Table of Contents

• The document has an organized table of contents, listing each section and its page number.
• Key topics covered in the module are safety, introduction, hydraulic symbols, basic hydraulic systems, hydraulic fluid, hydraulic tanks, filters, and pumps, and more.

Safety in Hydraulics

• Hydraulics operates at high pressures, requiring careful handling.
• Common safety risks include flying debris, dermatitis, cancer risk from fluid contact, burns, and crushing injuries.
• Safe practices include PPE (personal protective equipment), appropriate lifting techniques, and house-keeping measures.

Introduction to Hydraulics

• Hydraulics is the transmission of force and movement using pressurized fluid.
• Three methods for transmitting power are mechanical, electrical, and fluid power.
• Fluid power, coupled with both mechanical and electrical, is a key topic covered in the module.

Basic Hydraulic Symbols

• Hydraulic symbols provide clear representations of how each hydraulic component functions.
• A schematic, a road map or representation of a hydraulic system is useful for identifying potential problems or causes of a potential failure.

Basic Hydraulic System Components

• Components include: reservoir/tank, pump, filter, valves, hydraulic lines, prime mover, and actuators.

Categories in a Hydraulic System

• Control Devices: Control the direction of the hydraulic fluid flow from the pump to the actuator.
• Output Devices: Convert hydraulic power to mechanical power (linear or rotary motion).

Hydraulic Fluid

• Hydraulic fluid is the lifeblood of a hydraulic system.
• Important properties include (but are not limited to): compressibility, shear, viscosity, temperature, and compatibility. Water is generally not a suitable alternative as a hydraulic fluid because it corrodes parts and it has a lower temperature operating range than hydraulic oil.

Hydraulic Tank (Reservoir) Functions

• Fluid storage: Providing a consistent supply of fluid to circulate.
• Cooling: Allows heat to be dissipated.
• Separation of air and contaminants: Facilitates the separation of contaminants from the fluid.
• Fluid Level Control: Ensures sufficient fluid for the system's requirements.

Hydraulic Tank Characteristics

• Storage: Keeps fluid in a cool, dry area.
• Ventilation: Allows air to enter and exit.
• Baffles: Guide the fluid flow to prevent contamination.
• Components: Sight glass, drain plug, breather, and filters aid in the operation or maintenance of the tank.

Filtration

• Filters are crucial for reducing contaminants.
• Contaminants can enter the system during assembly or operation.
• Types of contaminants include metals, polymers, and fibers.

Filter Parameters

• Filters are rated by their maximum pressure and flow capabilities.
• Microns measurement represents the smallest size of particle that can be filtered.
• Beta rating is the ratio comparing the count of particles of a given size before and after filtration (i.e. efficiency).

Types of Filters (including suction and return)

• Suction filters are located at the inlet of a pump to prevent contaminants.
• Return filters are placed in the return line to catch contaminants before they re-enter the system.

Pumps

• Pumps are used to move hydraulic fluid.
• Types of pumps include positive displacement (gear, vane, piston) and non-positive displacement.
• Important characteristics of pumps include flow rate, mode of displacement, and resistance.
• Factors that can destroy a pump include aeration (air entering the suction line), cavitation (forming air bubbles in the liquid inside the pump).

Flow

• Understanding laminar (smooth, orderly) and turbulent (irregular) flow is important
• Flow is affected by pump RPM, restrictions in the system and other factors.

Prime Mover

• Electric motor (efficient, no emissions, easy maintenance)
• Diesel engine (uses chemical energy, high power in a narrow range, complex construction.)

Power Rating

• Drive unit power is typically calculated using flow rate and efficiency factors

Hydraulic lines

• Hydraulic lines transport fluid from the reservoir to the pump and then to the actuators.
• Materials include steel pipes, or hoses and fittings.
• Important considerations in selecting lines include temperature, working pressure, components, materials and environmental conditions.

Accumulators

• Accumulators store pressurized fluid that can be used to help with energy storage, emergency operation, shock absorption, or compensate for volume changes.
• Types of accumulators include bladder, diaphragm, piston, spring, and loaded weight, which are useful in varying applications.
• Cautions on accumulator use may concern pressure, positioning and the use of appropriate tools.

Pressure Control Valves

• Pressure relief valves and pressure-reducing valves safeguard the system from excessive pressure.
• Pressure relief valves maintain a consistent pressure and pressure reducing valves regulate flow and pressure from higher pressure to lower pressure points.

Flow Control Valves

• Flow control devices regulate the flow rate, such as throttle valves, sequence valves, compensators, and other specific flow control devices.

Actuators

• Actuators receive the hydraulic power and convert it into mechanical force (e.g., linear or rotational motion)
• Types include cylinders (single acting and double acting—including those with variable damping and telescopic cylinders) and hydraulic motors (using various mechanisms for converting fluid power into rotational power).

Hydraulic Motors

• Hydraulic motors convert hydraulic energy into rotational mechanical energy.
• Types include gear, vane, and piston.

Pascal's Law

• Pressure applied to a confined fluid is transmitted equally throughout.
• This principle is used to multiply forces.

Hydraulic System Maintenance

• A 9-step general maintenance process is recommended.
• Specific maintenance tips are also given.