What is Hydraulics? Working Principle and Usage Areas

What is Hydraulics? Working Principle and Usage Areas

What is Hydraulics? Working Principle and Usage Areas

what is hydraulics, hydraulic systems, hydraulic working principle, hydraulic usage areas, hydraulic energy, hydraulic applications.

Introduction: Introducing the Power of Hydraulics

In today's modern world, it is vital to keep great powers in check and execute precise movements. The hidden hero that appears in many areas from construction machinery to airplanes, from factory automation systems to elevators: Hydraulic Systems. So, what is this hydraulics that we often hear about, and where is it used in our daily lives?

In this comprehensive guide, we will examine in detail the basic working principle of hydraulics, its advantages and surprising applications.

1. What is Hydraulics? Basic Definition and Scientific Basis

Hydraulics is derived from the Greek word "hydro," which means "water." In its simplest definition, hydraulics is the branch of engineering that studies the behavior of fluids (usually oil) under pressure and converts this pressure into force and motion.

Working Principle of Hydraulics: Pascal's Law

The scientific rule that underpins hydraulic systems is Pascal's Law. This law states:

The pressure applied to a stationary liquid in a closed container is transmitted to every point of the liquid and to the walls of the container of the same size and in all directions.

Thanks to this principle, the low force applied to a small piston surface in hydraulic systems is converted into an increased force by multiplying it on a larger piston surface.

Force Gain Formula:

: Input Force

: Output Force

: Input Area

: Output Area

This formula explains why hydraulic systems are so powerful.

2. How Does a Hydraulic System Work? Main Components

A hydraulic system consists of a number of components to transfer power and perform work:

Component	Mission
Hydraulic Pump	It converts mechanical energy into hydraulic energy (oil flow and pressure). It is the heart of the system.
Actuator (Cylinder/Motor)	It converts hydraulic energy back into mechanical energy (linear or rotational motion). It is the part that does the work.
Valves (Control Elements)	It controls the direction, pressure, and flow rate of the fluid. It is the brain of the system.
Tank (Reservoir)	It stores, cools and separates the working fluid (oil) from contaminants.
Filters	It cleans the hydraulic oil, extending the life of the system.
Pipes and Hoses	It transports oil under pressure between components.

3. Advantages of Hydraulic Systems: Why Are They Preferred?

Hydraulic systems excel in many areas compared to pneumatic (air power) and electric systems:

High Power Density: Capable of generating enormous forces, even in small sizes.

Precision Control: Excellent precision control over speed and force through valves.

Easy Reversibility: Ability to quickly and easily change the direction of movement with directional control valves.

Durability: It is more resistant to overloads and has a long life.

Wear Protection: The oil also lubricates moving parts, minimizing wear.

4. Hydraulic Usage Areas: Where Do We Encounter It?

Hydraulic systems are used in any industry where power and control are required. Here are the most common hydraulic uses:

Heavy Industry and Construction

Construction Machinery: Operating the moving arms, buckets, and outriggers of excavators, cranes, bulldozers, and loaders.

Hydraulic Presses: Sheet metal forming, molding, and joining large parts.

Forklifts: Lifting and lowering loads.

Manufacturing and Automation

CNC Machines: Tool change mechanisms and part clamping systems.

Robotics: Motion actuators of industrial robots with high payload capacity.

Transportation and Aviation

Aircraft: Opening and closing of landing gear, control of ailerons (flaps and ailerons), and braking systems.

Ships: Rudder control systems, hatch covers, and cranes.

Daily Applications

Vehicle Brakes: Hydraulic brake systems in cars (transmit force to the wheels with pressure).

Elevators: Elevator systems, especially in freight elevators and low-rise buildings.

Hydraulics, the Power Source of the Modern World

In summary, hydraulic systems are a pillar of modern industry, thanks to their ability to take a small force and convert it into a colossal force and control it with precision. The answer to the question of what is hydraulics is not just an engineering term, but also means the perfect combination of power and control.

If you work in a field that requires higher efficiency, more powerful machinery, and more precise control, hydraulic technology will continue to play a key role in your future.

 

Hydraulic Oil Selection: The Key to Extending the Life of Your System

 

Hydraulic oil selection, hydraulic oil viscosity, hydraulic oil duties, ISO VG, hydraulic oil standards.

Introduction: Hydraulic Oil is the Lifeblood of the System

In our previous article, we answered the question of what hydraulics are and examined the power and working principle of the systems. However, even the best-designed hydraulic system cannot work efficiently without the right hydraulic oil. Hydraulic oil doesn't just transmit power; it also takes care of vital tasks such as lubrication, sealing, and cooling.

So, how to choose the right hydraulic oil for your system among hundreds of different types of oils? What are the costs of making the wrong choice?

In this guide, we will explore the primary tasks of hydraulic oil, viscosity, which is the most important criterion, and the critical steps to consider when choosing the right oil.

1. The Four Basic Functions of Hydraulic Oil

Hydraulic oil, beyond being a simple fluid, serves four main roles within the system:

Power Transmission (Main Task): Moves cylinders and motors, transferring pressure from one point of the system to another.

Lubrication and Wear Prevention: Pumps form a film layer between moving metal parts, such as motors and valve seats, reducing friction and wear.

Cooling: Absorbs heat generated during operation and transports it to the tank, preventing the system from overheating.

Sealing: It minimizes internal leaks (loss of efficiency) by filling gaps at critical points.

Attention to Criterion 2: Viscosity (Fluidity Resistance)

Arguably the most important criterion in hydraulic oil selection is viscosity. Viscosity is the resistance of a fluid to flow.

Too High Viscosity: Oil thickens, pump strains, energy loss increases, and the system runs slowly.

Very Low Viscosity: Oil becomes thinner, lubricating film ruptures, internal leaks increase (efficiency decreases), and wear accelerates.

2.1. Viscosity Classification (ISO VG)

Viscosity is usually specified by ISO VG (International Organization for Standardization Viscosity Class). For example:

ISO VG 32: Oil with an average viscosity (cSt) at 40°C.

ISO VG 46: Oil with an average viscosity (cSt) at 40°C.

Rule: The ISO VG class recommended by the machine manufacturer (OEM) (e.g. VG 46) must be strictly observed!

3. Other Factors to Consider in Oil Selection

Viscosity alone is not enough. An excellent hydraulic oil must have properties that are suitable for the operating conditions:

1. Viscosity Index (VI)

Definition: It shows how resistant viscosity is to temperature changes.

Importance: High VI value oils should be preferred for machines operating in environments that are very cold or very hot outside. High VI prevents the oil from becoming too thick in winter and too thin in summer.

1. Additives (Performance Enhancers)

Commercial hydraulic oils contain various chemical additives to ensure the desired performance:

Oxidation Inhibitors: Slows down the degradation of oil due to contact with heat and air.

Rust and Corrosion Inhibitors: Protects metal surfaces from the damaging effects of water and moisture.

Antifoamers: Prevent oil from mixing with air and foaming, leading to compressibility and cavitation.

EP (Extreme Pressure) Additives: Essential, especially for systems operating under very high loads and pressures.

4. Steps to Choosing the Right Hydraulic Oil

Step	What Needs to Be Done	Importance
1. Manufacturer's Instruction	Check the ISO VG grade and specifications in the machine manufacturer's (OEM) handbook.	It is the most basic and mandatory step.
2. Operating Temperature	Evaluate the maximum/minimum temperature of the environment and oil in which the system operates.	VI (Viscosity Index) decides.
3. Pressure Conditions	If the working pressure is too high, turn to oils that contain special EP (Extreme Pressure) additives.	It prevents metal-to-metal contact under high load.
4. Cleaning and Filtration	Opt for a high-quality, clean-guaranteed oil.	Particulates are the number one cause of system failures.

Protect Your Investment

The right hydraulic oil selection not only ensures that your machine's performance remains at its peak but also prevents costly pump and valve failures, significantly reducing maintenance costs. Remember, hydraulic oil is not an expense but an investment in the longevity of your system.

 

Hydraulic Failures and Solutions: Keep Your System Running

Hydraulic failures, hydraulic system troubleshooting, pump failure causes, cavitation, hydraulic heating.

Introduction: Understanding Failures Means Preventing Them

While hydraulic systems are incredibly powerful and reliable, they are inherently vulnerable to failures because they operate with high pressure and precision. When a system stops, there are costly outages. For a successful business, it is vital to recognize and respond quickly to basic hydraulic failures.

In this guide, you will learn about the most common types of failures in hydraulic systems, their causes, and permanent solutions.

1. The Most Common Types of Hydraulic Failures

The vast majority of problems in hydraulic systems can be divided into three main categories:

1. Overheating (Thermal Load)

It is when the hydraulic system reaches temperatures higher than the normal operating temperature (usually between 45°C and 60°C).

Symptoms: Excessive temperature when touching the oil tank, hardening and leakage of sealing elements (seals), darkening of the color of the oil.

Key Causes:

Internal Leaks: The escape of high-pressure oil into low-pressure zones due to wear on valves and pumps, which generates heat through friction.

Incorrect Viscosity: Using oil that is too thick (high viscosity) puts excessive strain on the pump.

Lack of Cooling: Clogged or inadequate operation of the coolants.

1. Cavitation (Cavity Formation)

Cavitation is the formation of bubbles by the air or steam in the oil as a result of an excessive decrease in pressure at the inlet (suction line) of hydraulic pumps. When these bubbles move into the high-pressure zone, they implode rapidly.

Symptoms: Loud, grinding or gravel noise coming from the pump (distinguishable from many malfunction sounds), micro-level cavities (erosion) in the pump housing and rotors.

Key Causes:

Clogged Suction Line: The  pump is unable to suck in enough oil due to clogged filters or restrictive hoses.

Low Tank Level: Causes the pump to draw air.

Excessively High Viscosity: Oil thickening in cold weather and difficulty flowing in the suction line.

1. Contamination (Pollution)

Oil contamination is the main cause of 70% to 80% of all hydraulic failures. Pollution can be particulate (solid pollutants) or fluid (water, air).

Symptoms: Slow or erratic system operation, stuck (jamming) valves, premature wear on the pump.

Key Causes:

Ingress from External Environment: Dust and moisture entering through cylinder seals or vent covers.

Internal Production: Formation of metal particles as a result of abrasion.

Unauthorized Oils: Using the wrong type or low-quality oil.

2. Quick Fixes for Common Failures

Problem	Possible Cause	Solution Steps
System Overheating	Oil level low, coolant clogged, internal leak.	Clean the coolant, check the oil level, switch to the manufacturer's recommended viscosity.
Pump Running Noisy	Cavitation (air suction), coupling misalignment, low oil level.	Check the intake filter, make sure there is no air leak, top up the oil level.
The Cylinder Moves Slowly	Dirty or stuck valve, low pressure.	Improve oil cleanliness (filtration), check or replace valves.
No Pressure Builds Up	The pump is excessively worn, the relief valve is leaking, or it is incorrectly adjusted.	Check the pump status, check the adjustment and sealing of the relief valve.

3. Preventive Maintenance: Stop Breakdowns Before They Happen

Better than solving malfunctions is not to experience them at all. An effective preventive maintenance program maximizes system life:

Regular Oil Analysis: Periodically check the oil for wear particles, water content, and viscosity variations.

Filter Replacement: Replace filters as often as the manufacturer determines to prevent the buildup of contaminants.

Leak Check: Detect visible leaks and cracks early on all hose and seal connections.

Temperature Monitoring: Continuously monitor the operating temperature at critical points and respond promptly to sudden spikes.

Maintenance is Essential for Continuity

Getting maximum efficiency from your hydraulic systems and minimizing downtime is possible with the right oil selection (our previous topic) and a meticulous maintenance routine. It should be noted that most failures in hydraulic systems are caused by contaminants and neglected maintenance.