Oct 5, 2022 | News

A hydraulic system is made up of several complicated pieces of machinery that work together to complete a goal. Generally, that goal is to move something like a piston or fluids, but there are several different goals a hydraulic system can achieve. This article will cover the most basic hydraulic components involved in a hydraulic system and briefly describe what they do.

Hydraulic Hoses

Hydraulic hoses are the bridge that fluid flows through in a hydraulic system. It can connect to pumps, valves, hydraulic cylinders, and several other components.

These hoses are more durable than your average garden hose, as they typically move more intense fluids, like oil, for the system to work. Despite their hardiness, you need to be careful when installing them. All hydraulic hoses have a minimum bend radius; as the name suggests, this is how far a hose can be bent without damaging the inner tube or reinforcement layer. Because fluids constantly try to find the path of least resistance, they’re applying pressure to the hose’s inner sealings, trying to find a way out. By bending it too far and compromising the structural integrity of the inner tube and reinforcement layer, the liquid pressure pushes too intensely into the bend, potentially resulting in a leak or a burst.

The Liquid, Itself

You can’t have a hydraulic system without liquid! While water can be used as a hydraulic fluid, there are several reasons why it’s not.

  • Boiling Point – Hydraulic systems can run pretty hot, and the heat level only rises if placed outside in the sun. If the water boils, your hydraulic system will stop working quickly.
  • Freezing Point – In the same vein as boiling, you need your liquids to be liquid. If it’s freezing outside and your water turns to ice, your system isn’t going to work.
  • Metal Corrosion – Most systems have metal in them, the gear pumps, hydraulic cylinders, or wherever. Water naturally corrodes metal reasonably quickly, reducing the system’s lifespan considerably.

There are situations where water can work, but they’re limited. Oil doesn’t boil or freeze as easily as water. Rather than corrode, the oil lubricates metals. That’s why oils are most commonly used as hydraulic fluids.

Reservoir Tank

The primary purpose of the reservoir tank is to hold fluids for the pump to draw from, but it has several other jobs. Hydraulic fluid will be lost over time, so the reservoir has to carry an excess so the system can keep running without constant refilling. It also helps cool the fluids, and some systems partially clean it of contaminants.

Hydraulic Pump

Hydraulic pumps pump hydraulic oil where it needs to go. It converts the mechanical energy into hydraulic energy to complete a goal. More specifically, hydraulic energy is a combination of pressure from the condensed fluid and flow power given by the pump propelling it.


Actuators, also known as hydraulic cylinders, take the hydraulic energy and convert it back into mechanical energy. It takes the compressed hydraulic liquid’s physical power and uses it to move itself mechanically. Take a dump truck, for example. In a dump truck, hydraulic fluids are pushed by the pump into the actuators, giving them the energy they need to extend and drop the truck’s payload mechanically.

There are three different kinds of actuators:

  • Linear Actuators – These are the truck actuators we mentioned. These actuators move only in a straight line: up and down, or left and right.
  •  Rotary Actuators – Rather than moving in a straight line, these actuators rotate 360 degrees.
  • Semi-Rotary Actuators – Similar to rotary actuators, except they don’t spin in complete rotations. Rotary actuators will turn quickly in one direction, but the semi-rotary variant will rotate left, then switch to right and back.


We all know what a valve is. We use them every day when we clean our hands in the bathroom. Hydraulic valves control the direction of the fluid, but in the case of a hydraulic system, there are a few different choices of control valves.

  • Pressure Control Valve – This valve utilizes a pressure transmitter (PT) which detects how intense the liquid pressure is. The PT electronically sends this information to the valve to inform it when it needs to close or open.
  • Flow Control Valve – This is very similar to the pressure control valve; only this valve uses a flow transmitter (FT). Much like the previous PT, the FT measures the flow of liquid. It then informs the valve when to open and close.
  • Directional Control Valve – This valve is the most unique of the three. It allows operators to dictate where the fluid will go. As we mentioned before, with the hydraulic hoses, liquids will follow the path of least resistance. Without the directional control valve, the liquid will go in the most convenient direction the pump pushes.


While the reservoir might do some cleaning, the filters keep the grime out. Oil is not the cleanest fluid in the world. It ages, and it sloshes around metal all the time. It can get dirty. The filters stop this contamination from harming the system by catching most of it.

Power Source

Finally, the power source is one of the most essential pieces of this puzzle. This is going to be your hydraulic motor. You put oil in it, turn it on, and it powers your system like any other engine. However, you do have one more option open to you. You can install a hydraulic power pack, also called a hydraulic power unit. This is a one-piece unit comprised of a motor, fluid reservoir, and a pump.


PIRTEK is the industry leader in hydraulic and industrial hose services. Our professionally trained experts work with hydraulic hose issues every day. If you’re having trouble with your hydraulic hoses, call your local PIRTEK location, or visit our website for more details.


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Danny Stewart

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