Fluid Power

In the high school, we all came across the Pascal's Law. It says that when pressure is applied on an enclosed incompressible fluid, it gets transmitted equally in all directions.

 

Now, this leaves us with two very important points:

1. INCOMPRESSIBLE

2. FLUID

 

I'll take the 2nd one first. What is a fluid? To get the most simplistic answer I'd say, "Any thing that has the ability to flow is fluid". This most simple definition covers liquid as well as gases under the head "Fluid".

 

Now the first one. If an enclosed fluid is subjected to a force which tends to compress it, there are two possibilities. One is that the fluid's volume will decrease causing compression or if it does not compress under force, its pressure (force per unit area) will increase.

 

In modern industry, hydraulics play a key role. Enclosed systems using incompressible fluid are becoming more and more popular due to their versatility, reliability, compactness and accuracy. In older times, hydraulic systems used water as their prime fluid. A classic example of such system was the Tower Bridge of London which had steam engines to pump the river water into the lifting mechanisms of bascules. Modern hydraulic systems use hydraulic oils. In places where load is not an issue, pneumatic systems are used. These systems use compressed air for their operation.

 

I have seen systems using water, natural oil and now-a-days we normally use synthetic oil. Water was the most inexpensive fluid very easily available. The two most problamatic areas were:

1. It caused rusting of equipments

2. Getting contamination free water was tedious

 

Natural oil also had its own problems. Its quality rapidly deteriorated due to severe pressure and heat. This opened up the path for synthetic oils which are specifically designed for hydraulic systems.