|
Information Page Links:
Featured Centrifugal Pump Manufacturers
About Centrifugal Pumps
Centrifugal Pump Terms
Centrifugal Pump Associations
Centrifugal Pump Resources
Trade Shows
Featured Centrifugal Pump Articles
More Articles
|
|
About Centrifugal Pumps
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.
Featured
Articles
http://www.idcon.com/pdf-doc/centrifugalpumps.pdf
http://www.warrenpumps.com/resources/headvscapacity.pdf
Types of Centrifugal Pumps
- have a vertical shaft with a bottom suction, and the totally submerged
propeller is mounted near the bottom of the shaft and enclosed in
a
bowl. Axial flow pumps, used mainly for clear water service and wet
well installations, develop pressure by the lifting or propelling
action
of the impeller vanes on the liquid.
- are
made of corrosive-resistant materials.
- are directly connected to a power unit but do not have any less gearing
or shafting.
- are self-priming and capable
of handling clear water and water containing small particulate matter
up to .25” in
diameter. Some dewatering pumps are completely submersible and can
operate from any position,
including upside down.
- are a type of radial flow pump in which the fluid enters the impeller
from both sides. Due to the extending of the shaft into the suction
passage, double suction pumps are limited to pumping clear liquids.
- are mounted on the surface and use
an "ejector" (venturi)
mechanism to enhance suction ability. In a "deep well jet pump," the
ejector is down in the well to assist the pump in overcoming the limitations
of suction.
- are designed with wide unblocked passageways and are an intermediate
pump between radial and axial flow pumps. Mixed flow pumps develop
the
pressure partially with centrifugal force and partially with the lift
of the impeller vanes on the liquid.
- ,
which can be either horizontal or vertical, consist of two or more
pumps of similar capacity that discharge into each other in a series.
Progressively
the pumps develop a total head, the sum of the heads that each pump
has developed. A common shaft with several impellers, each with its
own volute, is rotated by a power supply, building up pressure in
stages.
- take in liquid through the center of the impeller and move it out along
the impeller blades at a 90-degree angle to the pump shaft. Radial
flow
pumps develop the pressure only with centrifugal force.
- are designed to permit uninterrupted water flow by automatically removing
air from the suction line and replenishing itself with water from
the
pump.
- have smaller openings and cannot handle as great of an amount of solids
or large solids as trash pumps can. There is no industry standard
dividing
semi-trash pumps from trash pumps, so both may be referred to simply
as trash pumps.
- are a type of radial flow pump in which the fluid enters the impeller
from one side, and the shaft does not reach into the suction passage.
Single-end suction pumps are used in applications where there are
large
solids, such as rags and trash, that would normally clog the pump.
- are designed to run inside the water source being pumped, eliminating
the suction lift limitations common with other types of pumps. Suction
pumps are ideal for private use, such as in well systems or irrigation.
- are used
to pump water or other fluids from low-laying surfaces.
- are heavy-duty centrifugal pumps that are designed to pump hundreds
or even thousands of gallons of water per minute, which contains
large
solids, such as twigs, sand, mud, soft solids and trash. Trash pumps
have deeper impeller vanes, incorporated with a larger volute discharge
opening, and are used in such applications as construction and agricultural
sites.
- turn the shaft and impeller at two different rpm levels with a two-speed
motor, allowing for optional pump capacity.
- are designed to have only the casing and the impeller submerged in
the pumpage for priming and the support bearings for the rotating
element
in a dry environment. Vertical cantilever pumps have no throttle or
bumper bushings or any rings at the impeller or submerged below the
maximum normal water level, and they are used in applications, such
as a sump or tank, in which it is necessary not to have a bearing
in
the pumpage.
- are used for deep-well pumping, as their motors are at ground level
and their pumps at or near the surface of the water.
- are inefficiently designed pumps
in which the impeller is recessed into the volute. However, vortex
pumps are practical in applications
that
require pumping of excessive solids.
- use
an electric motor to move water.
- extract
water from wells.
|
|
