Audel Pumps & Hydraulics
Chapter One
Basic Fluid Principles
Pumps are devices that expend energy to raise, transport, or compress
fluids. The earliest pumps were made for raising water. These
are known today as Persian and Roman waterwheels and the more
sophisticated Archimedes screw.
Mining operations of the Middle Ages led to development of the
suction or piston pump. There are many types of suction pumps.
They were described by Georgius Agricola in his De re Metallica
written in 1556 A.D. Asuction pump works by atmospheric pressure.
That means when the piston is raised, it creates a partial vacuum.
The outside atmospheric pressure then forces water into the cylinder.
From there, it is permitted to escape by way of an outlet valve.
Atmospheric pressure alone can force water to a maximum height
of about 34 feet (10 meters). So, the force pump was developed to
drain deeper mines. The downward stroke of the force pump forces
water out through a side valve. The height raised depends on the
force applied to the piston.
Fluid is employed in a closed system as a medium to cause motion,
either linear or rotary. Because of improvements in seals, materials,
and machining techniques, the use of f ... read full excerpt from Audel Pumps & Hydraulics, All New 6th Edition ebook
