Application of Pascal’s law in the hydraulic excavators

Pascals law in hydraulic excavators 1

Pascal’s law describes an important phenomenon that is widely used in real life in a variety of activities to reduce energy wastage. The most common systems where it finds the maximum use is in hydraulic systems no matter for what purpose you are using a hydraulic system in your daily life. Such a piece of common machinery that finds use in day-to-day life is an excavator which is a machine that helps in digging the ground for excavation purposes or construction sites besides other uses. Excavators are powered by hydraulic systems that help in lifting heavy loads. The explanation and wide application of Pascal’s law in hydraulic excavators are explained in this article along with all other hydraulic systems.

Pascal Law for Hydraulic

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What is Pascal’s Law?

Given by the scientist Blaise Pascal, Pascal’s law is an important principle in fluid mechanics that states that a pressure change at any point in a confined incompressible fluid is spread along with the fluid in such a way that the same change occurs everywhere. The formula for Pascal’s Law is our simple formula that is used to calculate pressure over any surface. It is as follows:

P = F/A, where P= pressure applied on the piston being considered,

F = force on piston being considered, 

A = area of the piston is considered

Explanation of Pascal’s Law

When applied to a hydraulic system, the simple explanation of Pascal’s Law is as follows. The law indicates how the pressure exerted over one piston is increased several times and transmitted through the hydraulic fluid to exert a multifold force on the other piston that helps to lift heavy loads.

What is an excavator? How does an excavator work?

As the name implies, an excavator is used in excavation activities and sites to dig through Earth. However, its biggest application is found in construction sites, lifting heavy goods to load containers and other mechanical jobs. The excavator is powered by hydraulic systems and a diesel engine t=which has high horsepower. The hydraulic systems that power the excavator’s arms use Pascal’s law to impart force sufficient enough to move the arms of the excavator. 

How does an excavator work

Hitachi Construction Machinery

Pascal’s Law and its Applications in Hydraulic Systems

Pascal’s Law has enormous applications in hydraulic systems and is not limited to the following:

Video: Application of Pascal’s law

Hydraulic Lifts and Pascal’s Law

A hydraulic lift finds enormous use in lifting heavy objects that work on the principle of Pascal’s law and uses hydraulic fluid. A narrow cylinder fitted with an airtight piston (A) is connected to a second cylinder greater in an area with another airtight piston (B) over it. Both the cylinders are filled with hydraulic fluid which is incompressible by the force or pressure applied on the two pistons. The Pascal law applies to such a system which can be used to calculate the pressure that needs to be applied to piston A to lift the platform over piston B. This process is widely used in vehicle lifting in workshops and other heavy goods in warehouses.

Hydraulic Lifts and Pascals Law
Brainly. in

The simple explanation is that the pressure remains the same on both the pistons depending on the area of the piston. It is easier to apply higher pressure on the smaller area piston than applying more pressure to the larger area piston. Thus, on applying higher pressure on the smaller piston, the same higher pressure gets exerted on the other side of the cylinder (on the larger piston) and it helps in lifting heavier loads kept on the larger piston.

Explanation of Pascals Law


Hydraulic Pump and Pascal’s Law

Hydraulic pump is yet another fascinating machine that converts mechanical energy into hydraulic energy working on the principles of Pascal’s law. Just like a hydraulic lift, this pump also consists of a narrow and thick cylinder filled with hydraulic fluid or oil. Air is pumped into the system through the narrow cylinder that creates a force strong enough to lift heavy objects joined with the thick cylinder.

Pascals law in hydraulic excavators

Hydraulic Brake and Pascal’s Law

Every time you see a vehicle halting, Pascal’s law is behind the scenes. The hydraulic braking system is used widely in all vehicles which work on Pascal’s principle. Hydraulic fluid filled in the container transmits the force from the brake pedal to the wheels that halt the car. The frictional force is behind the braking effect and is a very common and important use of this Pascal’s law. In fact, it is used in all vehicles starting from cars, buses, to heavy lorries as well.

Hydraulic Brake and Pascals Law


Application of Pascal’s law in an excavator

An excavator is a piece of giant machinery used mainly in construction sites and work. Its main function is to dig into the ground and remove ground material to create space for building works. It is powered by diesel most of the time and works fully on the principles of hydraulic systems. It can be used over large spaces and even can rotate 360-degrees on its own. A typical hydraulic excavator is composed of the following main parts but is not limited to:

  • Hydraulic Arm – containing a boom, arm, bucket, and cylinders
  • Counterweight
  • Engine 
  • Pumps for hydraulics
  • Undercarriage 

The excavator’s arms are lifted using high-efficiency engines and hydraulics that require diesel fuel. Both the arm and the excavator’s bucket are regulated and coordinated by three separate hydraulic cylinders. The various regulations and coordination movements lead to the free movement of the arm whether it is expanding or retracting. 

The Hydraulic systems used in the excavator’s controls are fully dependent on calculations and principles of Pascal’s law and work quite similar to the hydraulic lift, brake, or pump described above. 

hydraulic excavators Machine



Excavators are not only a common sighting in the urban era but also are a piece of indispensable machinery in rescuing and evacuation operations like removal of heavy trees and trunks in storm-hit areas. Excavators are partially fueled by hydraulic systems that help them to lift heavy loads be it for any purpose. Pascal’s Law of fluid mechanics is highly praised for all these innovations that make our daily life easier. We have given a brief explanation on the application of pascal’s law in a hydraulic excavator, this will help you to know these principles better.

Feature Image Source: Rock to Road

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