There are two types of hydraulic pumps: hydrostatic and hydrodynamic. They are used in hydraulic electric drives as well as in other machines. A pump is an engine that transforms mechanical energy into fluid power or fluid pressure. Inlet pressure multiplied by flow capacity should be able to overcome the outlet load. When automatic pumps operate, a number of forces cause a vacuum in the inlet and this pushes liquid into the system. Hydrostatic pumps can be fixed displacement or variable displacement while hydrodynamic ones have many shapes like this one. For example you have never seen hydrodynamic pumps but it is normal thing when we deal with hydrostatic ones. All categories of hydrostatic pumps work based on Pascal’s law.
Pascal’s law:
A change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points in the fluid.
Pressure exerted on a fluid in an enclosed container is transmitted equally and undiminished to all parts of the container and acts at right angle to the enclosing walls.
Alternate definition: The pressure applied to any part of the enclosed liquid will be transmitted equally in all directions through the liquid.
History of the hydraulic pump
The usage of hydraulic power dates back thousands of years to when the ancient Egyptians used water-based systems in their farming techniques. However, it was only much later that the principles governing hydrodynamics were discovered and made public.
1648: French physicist Blaise Pascal noticed that pressing a confined fluid produced force equal in all directions which could be utilized.
1738: Daniel Bernoulli, after almost a century, implemented Pascal’s research to pressurize water in pumps and mills using Bernoulli’s principle.
1795: Joseph Bramah invented his patented hydraulic press, which was the first of its kind in England and became one of the foundation blocks for the industrial revolution. All types of manufacturing equipment use hydraulic presses such as printing machines, cranes, cutting and stamping devices.
Hydraulic cylinders were first used on cranes about seventy five years ago but are now used for hydroelectric power generation. It is also preferred as it is used in controlling aircraft surfaces and even small water vessels. Many applications of this technology are spread across wide areas.
Hydraulic push, pull or lift can offer up to ten times the force than an electric motor can produce. A better way to use hydraulics is to maintain control and precision at all times while using hydraulic equipment.A more modern assistance, combining science and mathematics with the help of today’s advanced computer technology has brought hydraulic cylinder “smart”.
Next we should: understand the main components of the hydraulic pump
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