Centrifugal Pumps Industry Information
Centrifugal pumps are simple devices consisting of
only a few parts that are designed to move liquids. All centrifugal pump
manufacturers use an impeller and a stationary volute, also referred
to as the casing or diffuser, that houses the impeller. Centrifugal pumps
use these components to create the necessary force to move the liquid
through the pump and out of the discharge outlet. The impeller moves
the liquid away from the eye to the vane tips of the impeller, where
the high pressure is located, and from the outer edge of the casing.
The purpose of the volute is to take the velocity (or kinetic energy)
of the liquid and change it to pressure force through the increasing
size of its spiral shape. As the size of the volute increases, it acts
progressively to reduce the speed and increase the pressure of the liquid.
The process of centrifugal pumping works by converting mechanical energy into
kinetic energy, changing the pressure force. Mechanical force powers the shaft
to move the impeller. The impeller then uses vanes to impart kinetic energy or
velocity to the liquid inside the casing. This initial movement of the liquid,
called priming, purges the air from the casing. The liquid enters the centrifugal
pumps at the eye of the impeller. A partial vacuum, or low pressure point, at
the eye of the impeller is created both by the purging of the air and by the
liquid leaving the eye of the impeller.
Centrifugal pump manufacturers design products that are ideal devices for moving
fluids from one place to another. These centrifugal pumps deliver fluid at a
uniform pressure without pulsations or shocks. They are able to handle liquids
with high quantities of solids. Since centrifugal pumps have a simple construction,
they have a relatively low cost, as well as low maintenance costs. However, centrifugal
pumps cannot operate at high heads, are subject to air binding and usually requiring
priming. Centrifugal pumps operate efficiently in a narrow range of conditions
and do not handle highly viscous fluid well.
Centrifugal pumps are typically used to pump water, but they are also used for
moving oil and gas. Centrifugal pump manufacturers make the most commonly used
pump in the chemical industry. Other industries in which they find use include
refineries, nuclear power plants and the hydrocarbon and petrochemical industries.
Some centrifugal pumps are designed especially to handle corrosive liquids and
slurries and solids, which are often present in corrosive environments. For private
use, typical applications include well systems and low flow irrigation. Specifically
designed centrifugal pumps are utilized to move what is considered "trash
water," such as sewage.