Hydraulic systems such as jacks work by Pascal’s Law which states that whenever pressure is increased at any point within confined fluid, there is an equal increase in pressure throughout the container. All that means is that where pressure is applied to one point, it is then transferred to another point through some non-compressible fluid, thus if you have 2 pistons, one on each side, connected by a tube half filled with water and you press down on 1, the other will rise. Of course machines that use hydraulic systems are a bit more complex than that, but I hope you get the idea.
Hydraulic systems must not have any air bubbles in them because an air bubble can be compressed thus disrupting the way the system works or even causing complete failure. A vehicle braking system generally works by employing a hydraulic system and it is quite common to have to bleed the brake pipes after working on the braking system to ensure there are no air bubbles in brake lines. This is why it is important that proper hydraulic fluid is used as this has been specially formulated and is non-compressible so will ensure that the hydraulic system works to its optimum.
One of the earliest hydraulic pumps was recorded in the 3rd century BC where a force pump was built using a piston to push water through a pipe outside the bilges of a ship. Modern shipping still make use of bilge pumps but they are a bit more advanced these days. Hydraulic pumps are used extensively in many modern machines from aircraft to cranes to heavy plant machinery such as diggers. They are of course much more complex than the originals and operate under high pressure. The first hydraulic press was invented in 1795 by Englishman Joseph Bramah. This press has been adapted and developed into many modern machines including a car crush. The main advantage of hydraulic presses over mechanical presses is their ability to compress materials to the smallest volume possible.
Cranes and other All Lifting equipment have become essential pieces of equipment in several different industries these days. The hydraulic systems allow these machines to lift the heavy loads with ease and this is the main reason they are so popular in industries such as construction and in shipping. Keeping the hydraulic systems in good working order is very important both from a safety point of view and for efficiency. As mentioned earlier, air in the hydraulics is not a good thing to have and using the correct hydraulic fluid will help to keep the system working properly and protect it from overheating and wear and tear. There is a full range of hydraulic fluids available on the market which has been specifically developed for particular hydraulic systems.
Hydraulic systems of all sorts have advanced and continue to be developed to improve the efficiency of the machinery. So, the next time you need to change a wheel on your car with a bottle jack or see a crane mounted on a skyscraper or an earthmover working on a new road or even a forklift truck working in a warehouse, think about how these machines work and the wonders of hydraulics.