What Are the Basics of Hydraulic Systems?

The global hydraulics market reached a value of $37.4 billion in 2020.

Hydraulic systems are widely used for various purposes and can vary significantly in their design. But what is a hydraulic system? And how do they work? 

To find out, keep reading.

What Is a Hydraulic System?

Pascal’s law states that a change in pressure in an enclosed fluid is transmitted undiminished to all points in the fluid. This is the main principle behind hydraulic systems.

A system can apply a small amount of pressure and generate a much larger force. For example, if 10 pounds of force are exerted against an area of 1 square inch, it will create ten psi of internal pressure. If this is acting against an area of 10 square inches, it will generate 100 pounds of force.

Hydraulic System Components

A basic hydraulic system will have the following components:

  • Single Cylinder
  • Pump
  • Reservoir
  • Relief valve
  • 3-way directional control valve
  • Connectors
  • Lines

When the cylinder position returns using mechanical force, the control valve will be in neutral. This allows the fluid to flow through the valve and into the reservoir. When the valve shifts, the oil will travel to the piston side of the cylinder, making it move and causing the rod to extend.

If the valve is returned to neutral the oil will be trapped in the cylinder, which will stop it from moving. Pump flow then returns to the reservoir, and the valve shifts to the opposite direction causing the oil to travel back through and into the reservoir.

The system pressure can be pre-set, and the relief valve stops the pressure from exceeding this amount.

Hydraulic System Examples

The above description covers a fundamental hydraulic system. However, many different types are used in various industries, covering many applications.

Hydraulic Lifts

Hydraulic lifts are perfect for lifting and moving people or objects vertically. Mezzanine lifts and scissor lifts are two common examples, and hydraulic lifts are also used in shipping, construction, and waste removal.

Hydraulic Brakes

Braking systems in vehicles need to be very effective and reliable. Hydraulic brakes are an efficient way of providing braking force without the driver needing to apply too much pressure.

Hydraulic Steering

Hydraulic steering makes controlling vehicles easy and comfortable. The driver can steer with minimal effort, and the system absorbs some of the shocks that come from the road.

Hydraulic Jacks

Floor jacks and bottle jacks are ideal for lifting vehicles with ease. In addition, the hydraulic system can lift a vehicle off the ground without assistance.


A lot of equipment in the construction industry makes use of hydraulic systems. A typical example is hydraulic cranes, which can be fixed, or truck mounted.


Aircraft use hydraulic systems in several parts. This can include:

  • Doors
  • Brakes
  • Landing gears
  • Steering
  • Wings

Hydraulic systems are perfect for aircraft as they are easy to maintain and work well in all conditions.

Reliable Hydraulic Systems

If you need a hydraulic crane, or any parts/maintenance, the team at Kor Pak has you covered. Click here to contact us today and find out how we can help you.


Posted in Industrial Brakes and Clutches.